June 23-26, 1997 - Detroit, Mich.,
USA 
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June 23-26, 1997 - Detroit, Mich.,
USA
Note: This is a preliminary program as of March 28, 1997. Papers on the technical program and order of presentation are subject to change.
Session A
General Session I
June 23 (Monday Afternoon)
Session Organizer & Chairman: Harry J. Litsch, CEF-SE, H.J.
Litsch Consultants, Inc., Bethlehem, PA
1 p.m.--Plating Development with Pourbaix Diagrams
Gene Calvert, & Dr. Burt Shah, Boeing
Commercial Airplane Group, Wichita, KS
Pourbaix Diagrams have long been a method used to explore
the thermodynamics of metal. They graphically show regions where the
different metals tend to corrode or are stable. This is based on pH
and redox potentials. In the past, these diagrams were presented in a
static form that required many interpretations. Today, this
technology has been married to the power of computers. With this
marriage, these diagrams can be tailored to a specific application
and become a very powerful tool for understanding electrochemistry.
An acid chloride zinc-nickel alloy bath was refined with the use of
this tool. These refinements include a tremendous increase in
covering power, adhesion to stainless steel without a prior strike,
and greater stability of the bath.
1:30 p.m.--Nuts & Bolts of Understanding Balance Sheets
Edward Kittridge, Hawkins International,
Harvey, IL
The understanding of the basics of financial balance sheets and how
the various aspects impact on businesses will be covered. Also to be
discussed are facts that one needs to know when dealing with a banker
and/or investor.
2 p.m.--Study on the Chemical Polishing Stain-less Steel
Professor Fang Jing Li , Wu Yong, Han Ke
Ping Gul Technologies Singapore PTE LTD, Singapore
Influences of the solution components and operating conditions on the
polishing effect during chemical polishing of stainless steel were
studied quantitatively with reflective and gravimetric methods. The
optimum polishing technology for stainless steel was obtained with a
near mirror-bright surface.
2:30 p.m.--Pulsed Electrodeposition of Rough Copper Coatings
Professor Sergei S. Kruglikov, Dr. Sci., Dr.
Michael M. Yarlykov & Lyudmila M. Velesevich,Mendeleyev
University of Chemical Technology, Moscow, Russia
Copper was deposited from sulfate solutions by alternating
high- and low-polarization pulses. In the former, cathode
polarization was so high that very fast growth of microprotrusions
and the formation of new microdendrites took place as the result of
strong antileveling. In the latter, metal microdistribution was
uniform, microdendrites thickened and attained the necessary
mechanical strength. True surface area and, correspondingly,
plastic-to-metal bond strength can be increased many times by
depositing a thin microrough metal layer (e.g., copper) on the metal
substrate. The deposit's morphology and adhesion properties were
shown to depend mainly on the ratio of the quantities of copper
deposited during high- and low-polarization pulses.
3 p.m.--Decorative Metallization on Plastics
Dr. Brent Lee & Youguang Liu, Vacuum
Plating Technology Corporation, San Jose, CA
Increasing demands for a quality metallic finish over
plastic products create a great opportunity for the vacuum coating
industry. Over the years, the plastics industry has made many
improvements. As a result, plastic products are now light in weight,
strong, easy to mold into a desired shape, non-corrosive, and, most
of all, low cost factors make plastic the material of choice.
Al-though improved, many plastic products still maintain a cheap
appearance. A major disadvantage of plastic products is that they
deteriorate under ultraviolet light. High quality metal films coated
over the plastic can overcome these draw-backs. A method for plasma
synthesis of metallic film deposit on a plastic surface will be
de-scribed. Cathodic Arc Plasma deposition, a branch of PVD
technology, provides an efficient and economical way of producing
metal plasma for deposition. In contrast to gaseous plasmas, the
metal plasma ion sources are not produced by gaseous ionization, but
by micro-explosions at the surface of the solid source material by
cathode arcs in a vacuum chamber. The metal plasma deposition
technique provides a means for pre-forming surface modification and
material synthesis with a range of features and properties that could
be valuable in many ways. For plastic substrates, care must be taken
to block the heat generated by the vacuum arc source.
Production-sized equipment is designed and built to apply metallic
coatings to large substrate areas. Advantages are as follows:
One-step coating process; super-strong adhesion; various types of
metal sources to produce a variety of colors; and can coat complex
shapes and large area substrates.
3:30 p.m.--Evaluation of Phosphatability of Steels by an Impedance
Technique
Jeong-Real Park, Pohang Iron and Steel
Company, Ltd., Chonnam, Republic of Korea
In this work, a phosphated steel surface has been examined by
electrochemical impedance spectroscopy at its varying open-circuit
potential with time in a neutral salt solution rather than by highly
cathodic or anodic polarizations. Its impedance data have been
analyzed by comparing with the results of bare surface to yield the
surface coverage ratio of the phosphate coating and the charge
transfer resistance through the inter-face. The ratio has been proved
to be in good agreement with the observations by other methods so
suggested to be substituted for conventional evaluations. The
resistance has accounted well for the corrosion degradation of the
interface.
4 p.m.--A Proposed Investigation into Aerosol Formation at the
Surface of Open Tanks
Dennis R. Hanlon & Adam Chmielewski, KCH
Services, Inc., Forest City, NC
Recent advances in laser spectroscopy allow researchers to
gather data that was unobtainable and gain a detailed understanding
of aerosol formation at plating tank surfaces. The focus of this
paper will be to characterize emissions and investigate improved
control devices for chromium solutions from open plating tanks using
this technology.
Session B
Alloy Plating
June 23 (Monday Afternoon)
Session Organizer & Chairman: Myron Browning, CEF, Matrix
Technologies, West Hills, CA
1 p.m.--High Speed Ni-W Alloy Electroforming
Professor Chein Llo Huang, Soochow
University, Shin-lin, Taipei, Taiwan
Our earlier work showed that the internal stress of nickel
or nickel-tungsten electroforms in-creased with increasing current
density. There-fore, low current density is necessary to have a
low-stress electroform. In this work, optimum organic additives with
reduction group were added to the Ni-W electroforming bath to reduce
the hydrogen content in the deposit at higher current densities,
resulting in a lower internal stress at higher current density. A
high-speed electroforming of Ni-W alloy was obtained.
1:30 p.m.--Electrodeposition of Fe-Ni-P Alloys for Wear
Resistance
Professor Hetong Guo, Shulan Liu & Hui
Liang, Tianjin University, Tianjin , Peoples Republic of
China
Fe-Ni-P alloy coatings in which the Fe content is more than 90% can
be deposited by adding NiCl2 and NaH2PO2 in an ordinary ferrous
chloride bath. It was shown by experiments that the codeposition of
Fe with ZP met some difficulties, but indicated deposition of P was
easily carried out after a certain amount of Ni salt was added to the
bath. These kinds of coatings have the properties of higher hardness,
lower residual internal stress, and better wear resistance, when
compared with general iron coatings.
2 p.m.--The Preparation of Ni-S Alloy by Electroplating Method
Professor Ruifang Zhuang & Ligong Jing,
Nanjing University, Nanjing, Peoples Republic of China
Ni-S alloy containing from 17-23 (wt%) of sulfur was obtained in a
weak acidic bath containing Na2S2O3 by electroplating method. The
sulfur content and structure of the Ni-S alloy films were studied by
SEM observation, X-ray diffraction and XPS. The results showed that
films containing about 17-23 (wt%) sulfur consisted of a mixture of
microcrystalline and amorphous alloy. Hydrogen overpotentials at Ni-S
cathodes have been measured in 1N NaOH solution.
2:30 p.m.--Ecologically Safe Brightener Composition for Tin-Based
Alloy Plating
Professor Andrei N. Popov, Mendeleyev
University of Chemical Technology of Russia, Moscow,
Russia
A new brightener composition for tin-based alloy plating is
considered. It is compared to the latest inventions of the same type
from point of view of ecology. The brightener is used without
formaldehyde. An optimum bath's composition for POS-1 alloy plating
and its computer model will be presented. The computer model of
brightener bath realizes a 3D-simulation of the Electrodeposition.
The scaled presentation of deposits' grain is based on the
experimental data obtained with the aid of an electron microscope.
Session C
General Session II
June 24 (Tuesday Morning)
Session Organizer: Harry J. Litsch, CEF-SE, H.J. Litsch Consultants,
Inc., Bethlehem, PA Session Chairman: Dr. Earl Winters, Consult-ant,
Quakertown, PA
8 a.m.--Preliminary Evaluation of Electroplated Aluminum on Steel
Substrates
Keith Cramer & J. Peter Ault, P.E.,
Ocean City Research Corporation, Ocean City, NJ
A non-aqueous electroplating procedure for the deposition of an
aluminum coating has recently been commercialized in the United
States, The corrosion resistance and some mechanical properties of
aluminum-plated steel test specimens have been evaluated. Testing has
included natural marine atmospheric exposure, salt fog exposure,
fastener torque/tension, and paint coating adhesion. The performance
of the aluminum coating material during these tests will be
discussed. When applicable, the performance of the aluminum- plated
panels will be compared to other coating materials that have been
proposed as substitutes for cadmium plating.
8:30 a.m.--Electrochemical Surface Treatment of Stainless
Steels
Dr. Rustem A. Kaidrikov & Professor
Boris L. Juravlev, Kazan State Technological University, Kazan,
Russian Federation
It is known that the electrochemical treatment of stainless steels by
using solutions containing Pt or Pd ions provides the best corrosion
resistance. Corrosion resistance of stainless steels depends on the
content of Pt or Pd on the surface of the steel. In this paper, a new
electrochemical regime is suggested that allows a decrease in the
solution concentration of the alloyed ions (Pt and Pd) at constant
corrosion resistance. For example, 18Cr10Ni stainless steel was
electrochemically treated in a solution containing 5.85 g/L NaCl +
0.05 - 1.0 g/L PdCl2 and corrosion tested in 30% H2SO4.
9 a.m.--On the Kinetics of Chromium Electroreduction from Cr(III)
Electrolyte
Professor V. N. Kudryavtsev, E. G. Vinkurov
& V. V. Kuzentsov, Mendeleyev University of Chemical Technology
of Russia, Moscow, Russia, & S. R. Schachamayer, Eaton
Corporation, Milwaukee, WI
The aim of the present work was to understand why electrodeposition
of chromium from the usual trivalent chromium baths ceases altogether
after a certain time of electrolysis, but lasts in-definitely from a
newly developed bath. Kinetics of Cr+3 ions discharged from a Cr(III)
plating bath was studied by potentiostatic method. Limiting stages
for the reduction of Cr+3 to Cr+2 and to metal chromium have been
determined. In both cases, reaction rates for Cr+3 discharge are
expressed by kinetic equations of mixed control (i.e., electron
transfer and diffusion of Cr+3 ions are limiting stages).
The effect of the new bath pH on the rates of different reactions was
investigated. At certain potential that corresponds to diffusion,
c.d. of metal chromium stops and all the cathodic cur-rent is spent
for hydrogen ion discharge, leading to the formation of chromium
hydroxide. This potential changes from -1.32 to -1.28 V when the pH
of the solution is increased from 1.4 to 1.8. This effect is ascribed
to an increasing rate of OH- ions formation resulting from water
molecules cathodic reduction. The results will be compared with ones
received at studying a typical Cr(III) bath.
9:30 a.m.--Acceleration Mechanism of Thiourea for Electroless
Nickel Deposition
Professor Fang Jing Li, Gul Technologies
Singapore PTE LTD, Singapore
The influence of thiourea on the reduction rate of nickel
and hydrogen were determined. The results indicated that thiourea can
accelerate the reduction rate of Ni++ and H+ simultaneously, and
decrease the activation energy. The anodic and cathodic polarization
curves showed that thiourea does not affect the cathode process and
only accelerates the anodic oxidation rate of H2PO s . The results of
XPS and AES showed that the element composition of the Ni-P deposit
(A.C. %) were Ni (75.8%), P (22.7%), O (0.1%), and S (0.4%),
respectively.
10 a.m.--Abrasive Wear Resistance & Microhardness as a
Function of Heat Treatment
Jim Harrison & Dr. Jean Rasmussen,
Research & Development, Pioneer Metal Finishing, Green Bay,
WI
The microhardness and abrasive wear resistance of EN-plated parts
improves when heat-treated at high temperature. The temperature
itself and the treatment time are two important parameters
determining the end result. A three-dimensional correlation between
heat-treatment conditions and the technical quality of EN-plated
parts are not linear. This paper contains results from abrasive wear
testing and microhardness of heat-treated EN-plated panels. The
experimental design is based on statistical planning using Taguchi
orthogonal arrays.
10:30 a.m.--The Effect of Phosphorus Distribution in Copper Anodes
Upon Anode Sludging & Current Efficiency in Acid Copper
Plating
Richard W. Strachan, CEF-SE, The
International Metals & Chemicals Group, Shelby, NC
Phosphorus distribution has been measured in copper anodes of various
sizes and shapes manufactured by producers from around the world.
Scanning electron microscopy reveals phosphorus segregation in all
anodes, reflecting solidification and anode fabrication processes.
Laboratory electroplating tests have been performed on these anodes
to measure anode sludging and current efficiency. There appears to be
little correlation between anode performance in plating tests and
phosphorus distribution. This seems likely to be the result of the
fine scale of the phosphorus variations relative to the
phosphorus-copper film formation on the surface of the anode during
the plating process. The acceleration mechanism of thiourea from the
above results can attribute to the adsorption and interaction of
thiourea and H2POs on the active metal surface. As the results show,
the cleavage of the P-H bond of H2POs was accelerated and the
electrons were easily transported to the metal surface through atomic
S of thiourea and atomic H. Therefore, the reductions of Ni++ , H+ ,
and H2PO s on the metal surface were accelerated simultaneously.
11 a.m.--Utilizing Lead Assessor Training to Facilitate ISO 9000
Certification
Fred Mueller, CEF, Pottstown Plating Works,
Inc., Pottstown, PA & William Stokes, Hood &
Co.
Many surface finishers have customers who have obtained International
Standards Organization (ISO) certification. Lead Assessor training is
a key function for a member of the quality department of an
ISO-dedicated facility in obtaining and maintaining ISO
certification. Pottstown Plating Works customers have key people in
their organizations trained or in training as Lead Assessors. Surface
finishers can benefit by opening their facilities to peer review that
is part of the training required to become a Lead Assessor. Finishers
and their customers can assist each other by helping the finisher's
quality department conform to ISO standards. This paper presents a
case study of the cooperation in an ISO-audit/ peer review of
Pottstown Plating Works, Inc., by William C. Stokes of Hood & Co.
Session D
Electronics Finishing I
June 24 (Tuesday Morning)
Session Organizers: Linda Mayer, Lucent Technologies, Inc., Murray
Hill, NJ, & James M. Meade, Fidelity Chemical Products, Newark,
NJ Session Chairman: Linda Mayer
8 a.m.--Critical Evaluations of Lead-Free Solder Alloys &
Performance Comparisons
T. T. Hitch, K. Palif & A. N. Prabhu,
David Sarnoff Research Center, Princeton, NJ
The David Sarnoff Research Center has conducted extensive evaluations
on lead-free solders during the last three years. The approach was to
review many of the potential lead-free solders and to select those
for which were calculated a higher weighted sum of desirable property
values. By this means, we initially selected six solders. Solder
pastes were prepared of those alloys, along with crucible melts.
Experimental evaluations included solder wettability as a function of
temperature and flux activity, fatigue resistance (thermal and
isothermal), and melting point determinations.
The principle solder alloys studied experimentally included the
following: 96.5Sn-3.6Ag, 92Sn-3.5Ag- 4.5Bi, 90Sn-7.5Bi-2.0Ag-0.5Cu, a
Sn-AgCu alloy, 42Sn-58Bi, and 99.5Sn-0.5Cu. Throughout the work,
63Sn-37Pb was used as a control. (All comparisons are in wt. pct.)
The work also included limited experiments on three Zn-containing
alloys: 91Sn-9Zn, 66.5Sn-31.5Bi-3Zn, and 95.5Sn-3.5Ag-1Zn. This paper
discusses the methodology for solder alloy selection, solder
preparation processes, test selection, results, and conclusions.
8:30 a.m.--Throwing & Covering Power Evaluations of a Tin
Electroplating Chemistry by Hydrodynamically Controlled Rotating
Cylinder Throwing Power Electrodes and Hull Cells
Y. Zhang, F. Humiec, K. Murski, I. Kadija
& J. A. Abys, Lucent Technologies, Murray Hill, NJ
Throwing power and covering power are important properties of an
electroplating chemistry. Throwing power has been determined by
theoretical calculations and empirical methods. Equipment such as the
Haring-Blum cell is available to evaluate throwing power for
different plating solutions. It has some limitations, however, which
mostly result because of low agitation rates and irreproducible
hydrodynamic conditions.
Hydrodynamically controlled rotating cylinder throwing power
electrodes (RCTPE) and Hull cells (HCHC) were developed recently to
overcome the limitations mentioned above. Both provide a wide range
of agitation and reproducible hydrodynamic conditions. Utility of
RCTPE and HCHC is demonstrated by applying them to an electroplating
tin chemistry. Results will be presented in detail in comparison with
conventional approaches.
9 a.m.--Uncertainty Estimation in Layer Thickness Analysis by XRF
& Optical Cross Section
Glenn E. Staudt, AMP Inc., Harrisburg, PA
Understanding of uncertainty is requisite for proper interpretation
of results from coating thickness analysis. This has practical
consequences for process control, product disposition, and
measurement correlation. Traditional assessments typically exclude
major sources of uncertainty, however. Consequently, detailed
theoretical development is undertaken for two common methods: X-ray
fluorescence and optical observation of cross sections. Many sources
contribute to uncertainty of x-ray results, but the effect of
calibration predominates under many practical circumstances. The
uncertainty of optical measurement of thin coatings is dominated by
the inherent precision of optical observation. These theoretical
treatments are confirmed by empirical results.
9:30 a.m.--Control of Electroforming Solutions by Stripping
Voltammetry
P. Bratin, G. Chalyt & M. Pavlov, ECI
Technology, East Rutherford, NJ
One of the key parameters in controlling mechanical
properties of an electroformed deposit is the concentration of
organic additives. High current density and operation temperature
cause the rapid breakdown of additives, which requires their
continuous replenishment. The additives employed for electroforming
are usually natural multi-component products (derivatives of gelatin,
cellulose, etc.) that undergo multiple transformations during the
plating process. It is hardly feasible to determine separately the
absolute concentration of each individual component. Be-sides, such
information will have no practical use because the replenishment is
done with pre-mixed additives.
The alternative way is to measure the effective concentration of
additives in the production solution through their effect on the
plating process. CVS (Cyclic Voltammetry Stripping) is a well-known
analytical technique for control of additives in PCB plating. This
paper will discuss a new application of CVS technique for the
monitoring of organic additives in electroforming solutions. Results
of analysis of both synthetic and production solutions will be shown.
Application of CVS for the kinetic study of additive break-down will
be discussed.
10 a.m.--Low-boron Electroless Nickel Plated Through-hole Process
for Printed & Flexible Circuit Application: Advancements in
Quality, Productivity & Reliability
Frank Cane, Dr. Saad Doss & Hiroyuki
Ikeda, Fidelity Chemical Products Corporation, Newark,
NJ
Low-boron electroless nickel can be used to provide through
metallization amenable to the electrolytic copper process. The Ni-B
deposit has physical and electrical properties characteristic of
conventional electroless copper processes with the absence of
environmentally hazardous formaldehyde. Practical application of
low-boron electroless nickel through-hole metallization has been
demonstrated in the fabrication of both rigid and flexible circuits
compared to conventional electroless copper and direct metallization
processes. It has been confirmed that the low-boron electroless
nickel through-hole metallization process exhibits improved
electrical resistivity, surface-to-hole electrolytic plating ratio,
thermal stability, and reliability in comparison to the carbon-based
direct metallization process.
10:30 a.m.--Electroless Copper Metallization on Ceramic Circuit
Substrates
Xia Chuan Yi, Senior Engineer, The 13th
Research Institute of the Ministry of Electronics Industry, HeBei,
Peoples Republic of China
Electroless copper metallization technology for ceramic
circuit substrates that has advantages for both thick and thin film
processes has been developed. The etching behavior of ceramic
substrates was studied by SEM. The adhesion strength, sheet
resistance, thermal conductivity, and loss at microwave frequencies
were determined. Furthermore, temperature cycling, aging, and other
reliability tests were performed. The results of the tests and
application show that, by using this technology, copper circuit
patterns with strong adhesion can be fabricated onto alumina ceramic
substrates, with excellent mechanical, electrical, thermal
performance, and good reliability, which opens a new way for
metallization technology of microwave and hybrid IC substrates
Session E
Light Metals Finishing I
June 24 (Tuesday Morning)
Session Organizers: Patrick Scalera, Parker+Amchem, Madison Heights,
MI & Charles Grubbs, CEF, METALAST International, Minden, NV
Session Chairman: Charles Grubbs, CEF
8 a.m.--Using Casting for Surface Treatment (CAST) on an Al-Mg
Alloy
Anne Deacon Juhl, M. Sci. & Per
Møller, PhD, Technical University of Denmark, Lyngby,
Denmark
The term cast is used to see the correlation in casting
condition and anodizing behavior on an Al-Mg alloy. The sand-cast
Al-Mg alloy is anodized, and afterward the microstructure and oxide
is examined to see how this alloy is behaving in relation to a
sand-cast aluminum-silicon alloy. Also, the voltage-time response is
compared for the two alloys. The corrosion resistance of these oxide
layers is investigated by atomic spectrophotometry to see which one
gives the best result.
8:30 a.m.--Aluminum Wire Enameling: A New Surface Preparation
J. S.. Safrany, Pechiney, Voreppe, France,
& G. Golombler & B. Loreau, Aluminum Pechiney, Paris,
France
In many applications where the weight is an important
factor, aluminum has proved to be a good solution. In the electrical
industry, for example, aluminum has successfully replaced cop-per in
many cases. In addition, new surface treatments have helped to
penetrate some markets, such as enameled wire for electrical
windings. This paper will present a new surface preparation for
aluminum wire. This high-speed and easy-to-use process simultaneously
removes wiredrawing soils from the wire and prepares the surface for
enameling. It allows for excellent bonding of enamels, better than
with conventional cleaning processes.
9 a.m.--Metal Quality and Finishing
Richard W. Mahn, Novamax Technologies
(U.S.), Inc., Atlanta, GA
Metal quality prior to finishing of any aluminum product
cannot be over stressed. This is a constantly growing problem as
costs have been pushed downward, production rates have been pushed
upward, and more sources exist for metal in a free world environment.
This competition has created difficulty in obtaining high-quality,
consistent and uniform metal. This paper will discuss the principal
quality needs of the various types of fabricated products requiring
some kind of finishing, whether sheets, extrusions, or cast parts,
and whether anodized, painted or plated. The success of the finish is
directly dependent upon the quality of the metal surface to be
treated. While proper surface pretreatment is crucial, it highlights
the actual superficial and/or internal structural characteristics of
the base metal. The significance of this result on the final
appearance of whatever finish is used cannot be stated too often or
too vigorously.
9:30 a.m.--Solution Agitation in Sulfuric Acid Anodizing
Donald G. W. Ytterberg, Swiss Lenox, Inc.,
Arvada, CO
For 29 years, we have used mechanical mixers to provide
solution agitation for Type II and Type III anodizing tanks. In 1996
we installed new Type II and Type III anodizing systems. Stainless
steel heat exchangers have replaced lead cooling coils, aluminum
cathodes have replaced lead plate, and eductor agitation systems have
been installed to provide solution agitation. Simultaneously,
constant voltage anodizing has been replaced by constant current
anodizing using a proprietary process. This paper explains the steps
needed to design and install a solution agitation system with
consideration given to anodizing with high current density.
10 a.m.--Additives and Type III Anodizing-- Fact or Fiction?
Dr. Jean Rasmussen, Director/Research &
Development, Pioneer Metal Finishing, Green Bay, WI
Heat production during anodizing is closely replated to
the coating quality. The functionality of anodizing additives are
endothermic reactions, which adds an extra heat-removing mechanism to
the total process complexity. The use of additives is always
correlated with some other functional changes of the anodizing
conditions; very often both process temperature and the content of
sulfuric acid are changed. Therefore, it is natural to ask: Are
quality improvements really caused by the additives? This
presentation contains results from anodizing under various
temperatures and concentrations of sulfuric acid, with and without
additive. It will be shown that some of the quality improvements
claimed to be caused by the additive, can be obtained by just
changing temeprature and sulfuric acid concentration.
10:30 a.m.--New Electrolytic Two-Step Coloring Process
Chris Hanthorn, Novamax Technologies (U.S.),
Inc., Atlanta, GA
The process of two-step electrolytic coloring has long
been commercially popular because of its durability, economics and
ease of operation. The process has distinct cost advantages over
integral coloring processes and has superior outdoor durability over
organic dyeing or over-dyeing processes. The two-step electrolytic
process, how-ever, has been limited in the range of colors it can
offer. Traditionally, the only stable colors have been in the
champagne to black range. Today's technological advances have enabled
the offering of a rainbow of colors in a wide range of finishes. The
main advantage of these new colors is their durability. These new
finishes will not fade, peel, chalk, or corrode as organic dyes and
paints often do.
This paper will discuss the new two-step coloring process and compare
it to the traditional two-step electrolytic processes in terms of
ease of operation and performance characteristics. The advantages
over organic dyeing, enabling these new colors to be used outdoors,
will be highlighted.
Session F
Light Metals Finishing II
June 24 (Tuesday Afternoon)
1 p.m.--Seal Performance Standards & Specifications for Anodized
Aluminum
Anthony Ita, Henkel Novamax Technologies
(US), Inc., Atlanta, GA
Several specifications and performance standards are
utilized to evaluate seal quality in the aluminum anodizing industry.
This article reviews existing test protocols and performance mandates
designed to predict field reliability. A Relevance Index Analysis
criteria is presented as a comprehensive and effective quality
assurance program for consistent field performance.
1:30 p.m.--Microbump Formation on Aluminum Substrate
Takeshi Kobayashi, Hideto Watanabe &
Hideo Honma, Kanto Gakuin University, Kanagawa, Japan
Fabrication of nickel bumps on an aluminum electrode with
direct electroless nickel plating process has been investigated.
Electroless nickel deposition with hypophosphite as a reducing agent
is not started on the aluminum substrate (does not have a catalytic
action). Accordingly, nickel is initially deposited on the aluminum
using nickel displacement plating for the initiation of electroless
nickel plating. Activation of the aluminum surface is also an
indispensable process to initiate the electroless nickel plating.
Uniform bumps on the aluminum can be obtained by electroless nickel
plating after being activated with DMAB. Furthermore, nickel bumps
can be obtained without photoresist.
2 p.m.--Non-Chromium Conversion Coating Technologies for Aluminum
Alloys
Shawn E. Dolan, Lawrence R. Carlson, CEF,
Parker+Amchem, Henkel Corporation, Madison Heights, MI
This paper will present new conversion coating
technologies for treating aluminum alloys for both bare and painted
surfaces. Examples of commercial applications in various industries,
such as aluminum wheels, aerospace, extrusions, and marine
applications, will be discussed.
2:30 p.m.--Chemical Recovery Systems for the Aluminum Anodizer
Paul Pajunen, P. Eng, ECO-TEC, Inc.,
Pickering, Ontario, Canada
Although anodizing wastes are relatively simple to treat,
many plants use recovery equipment to reduce costs. Two recovery
techniques that are commonly used regenerate the etch and purify the
anodizing acid. This is due, in part, to the large amount of solid
waste (aluminum hydroxide sludge) that etching and anodizing
generates. Recycling this waste reduces chemical costs and,
frequently, improves product quality.
Regeneration of caustic soda etchants can dramatically reduce an
anodizing plants' solid waste by more than 80% while lowering caustic
soda usage by more than 70%. The alumina crystals that are removed
can be put to a variety of uses as an alumina substitute. Sulfuric
acid anodizing acids are considered spent and need to be discarded
when they reach a certain level of aluminum contamination, even
though they may still contain unused free acid. Recovery of this free
acid has been practiced for a number of years in a variety of
applications. A popular method of acid recovery employs a process
called acid sorption. This presentation will review the etch
regeneration and acid sorption processes; outline critical design
features; and provide field performance data and operation
experiences.
3 p.m.--Nickel is Class
Ralph V. Dixon, MacDermid, Inc., East
Berlin, PA
There is a new demand for high-quality nickel and chromium
finishes on aluminum, brought about by the cast automotive wheel and
motor-cycle industries. Satisfying these demands is not as easy as
one might imagine. We will explore the requirements, problems, and
some of the corrective measures required to produce these class
finishes.
3:30 p.m.--Aluminum New Developments: Anodizing Methods - Hard
Anodizing and Integral Color --Electrocoloring
Dr. Xavier Albert Ventura, Integral Centre
of Barcelona Spain, Barcelona, Spain
Some statistics of aluminum consumption will be given for
conventional anodizing. Sulfuric acid, oxalic acid, chromic acid,
integral and hard anodizing, modulated current anodizing for
thyristor controlled rectifiers, electrocoloring topics of sealing
hot and cold, electrophoretic and dip painting will all be discussed.
Some novel applications, such as solid-type lubrication, pre-coated
finishings and functional uses for electronics (in which Spain and
the European Community are fairly advanced) will be introduced.
Finally, applications of an alpha-alumina coating will be reviewed.
Session G
Electronics Finishing II
June 24 (Tuesday Afternoon)
Session Organizers: Linda Mayer, Lucent Technologies, Inc.,
Murray Hill, NJ & James M. Meade, Fidelity Chemical Products,
Newark, NJ
Session Chairman: Chwan-Tsann Wang, Lucent Technologies, Inc.,
Holmdel, NJ
1 p.m.--Surface Finish Requirements for Advanced Bonding
Techniques
James P. Langan, Langan Associates, Red
Bank, NJ
The high I/O interconnections required by recent
innovations in component technology are causing electronic
manufacturers to re-evaluate existing assembly techniques. As 0.4 and
0.3 mm pitch pads become customary, the presently preferred MO of
applying solder paste to hold components in place prior to reflow
soldering may no longer be yield or cost-effective. Prevalent
practices for attaching components to hybrid circuits
(thermocompression, thermosonic, ultrasonic, and eutectic bonding)
could yield the answer for attachment of ultra-fine pitch components
to printed circuits.
Surface finishes currently employed or being investigated for these
bonding procedures are tin, silver, nickel/gold, and
nickel/palladium. This paper details advantages/disadvantages of
electroless and electroplating processes and attempts to clarify the
pragmatism of selective finishes to maximize applicability when
several attachment techniques are required to obtain high first-pass
yields.
1:30 p.m.--Study of a Very Stable Alloy-Ratio Deposit from
Different Current Density Areas in Palladium-Nickel Electrolytic
Deposition
Kazuyoshi Okuno, Okuno Chemical Industries
Company, Inc., Osaka, Japan
2 p.m.--Applications of Electroless & Electrolytic Palladium
in PWB Manufacturing
Bruce Stacy, I. V. Kadija, L. J. Mayer, C.
Pan, J. A. Abys & H. K. Straschil, Lucent Technologies, Murray
Hill, NJ
The emerging demand for surface-mounted components and the
increasing cost of environmental compliance encourages the PWB
industry to evaluate new surface finishes. The requirements include:
uniform thickness distribution, solder-ability, bondability, non-lead
bearing, environ-mentally acceptable and economically favorable.
Palladium meets all these requirements and more. Palladium plating
processes are production proven in connector and semiconductor
packaging applications. This paper will describe how palladium can
simplify and improve the manufacture of printed wiring boards.
Characteristics of both electrolytic and electroless palladium
processes and their deposit properties will be presented. Emphasis
will be placed on solderability and wire bonding results before and
after accelerated age testing.
2:30 p.m.--Surface Evaluation of the Silver Finishes via
Sequential Electrochemical Reduction Analysis
P. Bratin, M. Pavlov & G. Chalyt, ECI
Technology, East Rutherford, NJ
Currently, tin/lead and gold coatings are the main metal
finishes employed in the manufacturing of the printed circuit boards,
providing protection of the substrate from oxidation and successful
wire bonding. With the industry trend to miniaturize the
interconnections, both printed circuit board fabricators and
assemblers are searching for the lower cost alternatives. One of the
commercially available alternatives to these finishes is an immersion
silver coating coupled with an extremely thin organic film. Because
the silver can be tarnished in the production environment, the
monitoring of the surface conditions is one of the major concerns for
soldering and wire bonding. Sequential Electrochemical Reduction
Analysis (SERA) was developed for the solderability assessment of
tin/lead coatings, and later has been extended to the identification
of the oxides and other reducible species, as well as the measurement
of their thicknesses. This paper will discuss the new application of
the SERA technique to assess the surface conditions of the silver
finish. The tarnishing products of the silver formed under ambient
and artificially created conditions will be analyzed. The protective
effect of an anti-tarnishing film will be evaluated. The influence of
the elevated temperatures (reflow) on the stability of the organic
inhibitor and the formation of the tarnishing film will be shown.
3 p.m.--Ductile Nickel/Palladium Multilayer Surface Finishes
Designed for Leadframe Packaging
Dr. Chonglun Fan, V. Kadija, J. A. Abys
& J. J. Maisano, Lucent Technologies , Murray Hill, NJ
Electrolytic palladium surface finishes have been
continuously improved for leadframe applications. Today, these
finishes can be employed at costs comparable to tin-lead surface
finish with extra advantages, such as superior functional performance
and considerable environmental impact reduction. In our developmental
efforts, we have optimized the palladium multilayer surface finishes
in both functional and environmental aspects by introducing a ductile
nickel underplate. Functionally, the solderability of the leadframes
are dramatically increased compared with using typical nickel plate.
High solder coverage and wetting speed are maintained on crack-free
surface finishes after trim-and-form operations and steam or thermal
aging. Environmentally, the need for activated fluxes is eliminated
in assembly. This significantly reduces the solvent and rinsing
requirements and minimizes contamination. In this paper, we will
introduce our recently obtained solderability and wire bonding
results on the palladium pre-plated leadframes and com-pare them with
the leadframes plated with typical nickel coating.
Session H
Waste Treatment & Recovery I
June 24 (Tuesday Afternoon)
Session Organizer & Chairman: Thomas Baker, Kinetico,
Newbury, OH
1 p.m.--Zero Discharge in the Metal Plating Industry Using an
Improved Ion Exchange Process
Juzer Jangbarwala, Hydromatix, Inc., Chino,
CA
A recent pollution prevention assessment of California's
metal plating industry showed that businesses are implementing or
researching technologies to "close the loop" on their rinsewater
systems and to achieve zero water discharge to the sewer. According
to this assessment, ion exchange technology is one of the preferred
technologies to achieve "closed loop" conditions. Unfortunately, the
traditional ion exchange process does not economically achieve "zero
water discharge" because the regeneration of the spent resin beds
produces a significant quantity of hazardous aqueous waste. This
aqueous waste is typically treated and discharged to the sewer. The
rinsewater recycling system discussed in this paper combines various
aspects of ion exchange and evaporation to achieve zero water
discharge. Although ion exchange and evaporation are not new
technologies, the ion exchange regeneration process has been improved
by reusing portions of the regenerants. The reuse of regenerants
drastically reduces the volume of generated aqueous wastes.
1:30 p.m.--Automated Waste Treatment
Stephen Koelzer, K & K Products,
Sunnyvale, CA
Physical and chemical changes invariably follow
established laws. Just as with plating, changing (mixed aqueous)
wastes states has empirically graduated into science from art.
Precipitation/ adsorption of cations/anions can be effected by the
same reactant. Therefore, separation by differential crystallization,
speciation of crystal forms (by manipulating valence states) and
less-than- equilibrium discharges are achievable within the same
tank. Crucial to processing is endpoint detection. Instrumentation is
used to efficiently control/automate treatment/purification,
recycling, reclamation. Results are facile solids settling/
filtration/dewatering, minimized POTW loading and toxicity reduction.
Applications are cited from photochemical machining, aluminum,
printed circuit board, nickel and cyanide waste streams processing.
Wastes may now follow a simple programming decision tree as
fundamental methods and techniques have become integrated.
2 p.m.--Technical & Economic Aspects of Electrochemical
Regeneration of Zinc Chromating Solutions
Professor Sergei S. Kruglikov, Dr. Sci.,
Mendeleyev University of Chemical Technology, Moscow, Russia, &
Dr. Vasili V. Okulov, AVTOVAZ, Togliatti, Russia
All chloride-free chromate solutions can be re-generated
electrochemically. Dissolved zinc is completely recovered, trivalent
chromium is re-oxidized to chromate and acidity (pH) of the solution
is restored. Batch operation is possible, but continuous process is
preferable because it allows the maintenance of constant solution
composition and properties of the chromate films. The regeneration
unit occupies 0.5 to 1 m 2 of floor space or is placed directly
inside the chromating tank close to one of its walls as a compact
(10-15-cm thick) electrochemical module. Savings were more than
$10,000 p.a. for one 500-gal plating tank with a black zinc
chromating solution. (Evaluation was based only on the cost
reductions resulting from the elimination of making up fresh
solutions every five weeks.)
2:30 p.m.--Water Recycling at Hughes Missile Systems Company
Paul W. Fecsik, Hughes Missile Systems
Company, Tucson, AZ
This paper discusses a plant-site water recycling system
in use that services a large number of customers with varying water
quality needs-- PWB shop, general finishing shop, prototype shops,
and maintenance area (scrubber systems, air handling systems).
Approximately 90% of the water is continuously recycled. Elements of
the system include an industrial waste treatment plant (IWTP) that
produces a reclaimed water product suitable for most areas of the
plant, a deionization area to supply higher purity water, and local
metal removal and deionization systems within process shops for
chrome and nickel removal with deionization for in-process recycling
(cop-per, tin and lead systems planned for 1997).
3 p.m.--Electrolytic Capture & Recycle of Ni & Zn from
Plating Waste
Professor David H. Swenson, Bruce
Hart,Michelle Vogtmann, Professor Albert Plausch, Professor George W.
Eastland, Jr., Kevin Wiese & Tom Vivian, Saginaw Valley State
University, University Center, MI; & Kevin T. Jungquist, Tawas
Plating & Powder Coating Company
Saginaw Valley University, in collaboration with Tawas
Plating and Powder Coating Company, has recently initiated a project
funded by the Michigan Department of Environmental Quality on methods
for electrolytic capture of Ni and Zn wastes from plating solutions.
A split cell design was previously found to be optimal for capture of
Ni, and preliminary studies suggest that a single cell for Zn capture
may provide optimum capture. Because market price for scrap Ni and Zn
is relatively poor, we are investigating the economics of dissolution
of the metals to their sulfate forms for reincorporation into the
plating baths.
3:30 p.m.--Chemical Conservation/Waste Minimization
Paul G. Page, P.E., TOLTEST, Inc., Plymouth,
MI
Many facilities in the electroplating and surface
finishing industry have implemented techniques to reduce rinse water
consumption and wastewater discharge. These techniques include spray
rinsing and counterflow rinsing. These methods do not reduce chemical
losses resulting from drag out, concentration of wastewater
contaminants, chemical usage for wastewater treatment, and wastes
generated from wastewater treatment, however. Chemical conversion and
waste minimization can be achieved through in-line modifications of
electroplating and other surface finishing operations. The cost
savings resulting from reduced chemical usage and waste disposal can
offset the capital costs of installing these modifications within 1
to 2 years. Finally, a means of being environmentally conscious can
be a way to save money.
4 p.m.--Legislation for the European Community on Waste
Characteristics: Lixiviation Tests for Electroplating Muds
Dr. Xavier Albert Ventura, Integral Centre
of Barcelona Spain, Barcelona, Spain
Industrial waste is subject to two categories of test for
lixiviation of extraction: Dynamic and static tests. The first one is
adequate to predict waste behavior at long-term deposition sites,
taking into consideration that study of the lixiviation speed of its
components is determined by the chemical properties, which includes
factors determining the contaminating agents' solubility and by the
transport properties that affect the ions' diffusion in the solid, as
well as the hydro-dynamic system. This study is centered on the
static lixiviation tests, given the fact that this is the most usual
mechanism for the different legal frames to characterize and identify
an industrial waste as a dangerous and toxic waste (RTP). These type
of extraction tests essentially consist in putting the waste in
contact with an extractor fluid in a high relation liquid/solid
(waste) by means of a vigorous agitation during a defined time at
room temperature.
Session I
Electronics Finishing III
June 25 (Wednesday Morning)
Session Organizers: Linda Mayer, Lucent Technologies, Inc.,
Murray Hill, NJ, & James M. Meade, Fidelity Chemical Products,
Newark, NJ
Session Chairman: James M. Meade
8 a.m.--The Trend Toward Pd/Ni Contacts in High Density
Interconnects
Lawson Williams, Ranoda Electronics, Inc.,
Miami, FL
Quality is the number-one requirement for high-density
interconnects, but competitive cost reduction is the second most
important factor. Explosive growth in demand for high density
connections in personal computers, disk drives, and communication
products is moving connector suppliers to shift from hard gold
plating to state-of-the-art palladium-nickel contact faces with a
low-cost gold flash. For high density interconnects with contact
pitches as close as 1 mm for use in surface mount products, the
benefits of palladium-nickel contacts can be superior to hard gold.
Fully 85% of Ranoda's products now use Pd/Ni contacts. This paper
reports on the three trends: The use of Pd/ Ni for high-density
interconnects in low-cost, high-end products; concurrent team efforts
among connector specifiers, connector suppliers, and material
suppliers; and the development efforts toward even lower-cost
materials, including cobalt.
8:30 a.m.--Extended Thermal Aging of Precious Metal Finishes Used
in Automotive Connectors
Gerald R. English & Therese R. Souza,
Handy & Harmon, North Attleboro, MA The contact
resistance of cobalt-hardened gold, nickel-hardened gold,
gold-flashed palladium, and gold-flashed palladium-nickel before and
after thermal aging at 135 o C was measured. Con-tact resistance
readings were taken at 0, 1,000, 2,000, and 3,000 hr at loads ranging
from 0.49 to 2.94 Newtons (50 to 300 gf). The total precious metal
thickness was less than one micron. The porosity of the samples was
measured with standard porosity testing techniques. The surface
chemistry was examined before and after aging. Additionally, Auger
electron analysis was conducted after sputtering 25 nm into the
surface on samples that were aged 3,000 hr. This paper will discuss
causes of observed changes in contact resistance.
9 a.m.--Palladium-Nickel Electrodeposits-- Properties &
Selection
Michael Toben, LeaRonal, Inc., Hauppauge,
NY
Palladium-nickel alloy electrodeposits comprising between
70 and 85% palladium are becoming increasingly accepted as viable
connector finishes. Within this range of alloy compositions, notable
differences in the metallurgical and functional properties of the
deposit exist. The current work describes the influence of alloy
composition on deposit grain structure, wear resistance, internal
stress and ductility as a means to assist the user in selecting the
best composition to satisfy a particular end-use requirement. A
historical review of electrodeposited palladium and palladium alloys
in the electronics industry is also presented.
9:30 a.m.--New Pd/Ni Plating Bath: Chemically Benign &
Environmentally Friendly
Irina Boguslavsky, J. A. Abys, H. Straschil,
J. J. Maisano & V. Eckert, Lucent Technologies, Murray Hill,
NJ
Most conventional Pd and Pd/Ni plating chemistries contain
ingredients that make them very corrosive towards base metals and
stainless steel components. Typically, they also operate at high pH,
which causes strong chemical odor and requires frequent pH
adjustment. This can make the Pd plating process costly and
environmentally hostile. A new Pd/Ni plating chemistry was designed
with the objective of reducing the bath corrosiveness towards
stainless steel and copper alloys, decrease chemical odor and ph
adjustment. Characterization of the bath is presented in the paper.
The effect of the bath components and plating conditions on Pd/Ni
alloy composition and material properties is described. The bath
plates Pd/Ni deposits with excellent appearance, ductility, corrosion
and wear resistance. The chemistry causes negligible corrosion of
stain-less steel and copper; it has practically no chemical odor and
requires minimum pH adjustment. The material properties of the Pd/Ni
deposits plated from this bath are demonstrated as well.
10 a.m.--Switch-mode Power Supplies & Their Application in the
Electroplating Industry
Peter Cambria, Rapid Power Technologies,
Inc., Brookfield, CT
High power switch mode power supplies have been available
for more than 15 years, but their primary use was for the
semi-conductor testing industry. Only recently--within the past four
years--have manufacturers begun selling them as an alternative to
other power supplies in the electroplating market. The advantages of
this type of unit are many, including: Smaller size, less weight,
extremely low ripple, and precise regulation.
There are drawbacks, however, to taking equipment primarily designed
to be used in clean, air-conditioned rooms and putting it in a
plating atmosphere. The second generation of switch mode power
supplies, totally sealed and designed specifically for the corrosive
atmosphere of a plating shop, is now available, with many
state-of-the-art features.
Session J
WORKSHOP
Environmental Technology In Latin America
June 25 (Wednesday Morning)
Session Chairman & Workshop Leader: Peter A. Gallerani, CEF,
Integrated Tech., Inc., Danville, VT
8 a.m.--Opportunities in the Metal Finishing Markets of Brazil
& Mexico.
Brazil and Mexico are major centers of the metal finishing industry,
accounting for more than 8 billion of annual output -- even excluding
the automotive sector. Metal finishing industries in these countries
are in rapid transition as they face fierce world-wide competition,
falling tariff barriers and pressures from new health, safety, and
environmental regulations. These challenges are driving demand for
new equipment, processes, services, and investment. This workshop
will assist U. S. suppliers to participate in these markets by
providing information about available opportunities and practical
advice. The workshop will include representatives from the metal
finishing industries of Latin America, as well as experienced U. S.
practitioners, who will share their knowledge and outline strategies
for penetrating these major markets.
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Session K
Corrosion in Electronics
June 25 (Wednesday Afternoon)
Session Organizer & Chairman: Dr. I-yuan Wei, AMP, Inc.,
Harrisburg, PA
This session is dedicated to the honor of Richard E. Baker, CEF-SE,
of Baker Consultants, Winter Springs, FL. Mr. Baker's career of more
than 40 years in the telecommunications industry focused on the study
of corrosion in electronics. He is a technical specialist for
educational development for the AESF and has been one of the
Society's key instructors, organizers of technical conferences, and
author/reviewer of educational materials for more than 17 years. He
received the AESF Order of Past Presidents' Award in 1989.
1 p.m.--Corrosion in Electronics--A Historical Perspective
Richard G. Baker, CEF-SE, Baker Consultants,
Inc., Winter Springs, FL
Over the years, electronic devices and equipment have been
shown to be susceptible to the deleterious effects of a wide variety
of atmospheric contaminants. This paper will give the results of
number of investigations associated with those corrosion- related
failure mechanisms that the author has found electronic devices to be
susceptible. It is hoped that these may serve to alert the finisher
to the types of corrosion-related problems he or she may not have
considered. The effects of a number of environmental contaminants on
the unexpected premature corrosion induced failures in electronic
equipment and/or devices will be discussed from a historical
perspective. The remedial actions necessary to prevent such failures
are also addressed.
1:30 p.m.--Properties of Electroless Nickel Deposits: Specifying
& Measuring Problems
Dr. Jack Horner, Milford, MI, & Brad
Durkin, MacDermid
In specifying EN deposits, it should be recognized that
the properties of the deposits can vary widely with the phosphorus
content, along with other less well-known factors. It also should be
recognized that the measurement of these proper-ties is subject to
wide variations, some known and some less well-known. This paper
discusses some of the experiences of the authors in the use of some
of these test methods. Among the test methods discussed are
microhardness, corrosion resistance and the resistance to the salt
spray (fog) test, ductility, tensile strength, bend tests, and
internal stress tests. Those who specify, produce, or use electroless
nickel deposits should find this of interest.
2 p.m.--Corrosion of Joints Used in Electronics
Dr. Richard Haynes, Richard Haynes
Consult-ants, Princeton, NJ
Plating and surface finishing technologies are essential
to the electromagnetic compliance industries (EMC). One of the most
common failure modes in electronic products is corrosion of the
joints between conductive materials. Galvanic corrosion of these
joints can cause electromagnetic interference (EMI), electrostatic
discharge (ESD), electrical overstress (EOS), and increase
susceptibility of electronic products to externally generated
electronic noise. This paper reviews the conductive materials and
surface finishes commonly used in making joints and the technical
principles used in the proper choice of materials, discusses design
guidelines for joints that should be used in electronic products, and
summarizes implications regarding the selection of conductive
materials and surface finishes that could increase the life of the
electronic products. New developments are needed in plating materials
and surface finishes in present and future electronic products.
2:30 p.m.--Practical Aspects of Porosity Testing of Electronic
Contacts
Robert A. Michelson, AMP, Incorporated,
Harrisburg PA
Numerical values of pore counts are not as significant as
determining the root causes of the porosity and applying the
knowledge to improve the manufacturing process. This paper will deal
with the porosity testing process and how to apply failure analysis
to determine the root cause of the porosity. Comparisons between
different porosity test methods and the need to have well-trained
porosity test technicians will be discussed.
3 p.m.--Corrosion Control for Metallized MCMs & Hybrid
Circuits
Donald W. Baudrand, Consultant for
MacDermid, Inc., Waterbury, CT
Corrosion is defined and described for electronic devices.
The results of corrosion, including oxidation, loss of contact
resistance, current leak-age, shorts, and diffusion changes in hybrid
circuits are discussed. Diffusion of metals resulting in nickel,
copper, or silver in the surface layer which corrode or change the
surface characteristics is discussed. Diffusion barriers and
corrosion protection methods are suggested.
3:30 p.m.--Enhanced Solderability of PWB Substrates with Improved
Organic Solderability Preservatives (OSP)
Michael Carano, Electrochemicals, Inc.,
Maple Plain, MN
A critical success factor in achieving sufficient
solderability of surface mount and through de-vices is the ability to
preserve the solderability of the surface finish. OSPs have been
known to provide excellent protection against the oxidation of the
base metal. There are concerns from assemblers and bare board
fabricators, however, that these coatings are not capable of
maintaining sufficient solderability of the base metal on multiple
thermal pass assembling operations such as required by mixed
technology boards. Other concerns relate to the consistency of the
applied coating during normal processing, as well as the actual
thickness of the OSP. Compatibility with no clean fluxes is also a
major requirement. This paper will address these and other concerns,
including the electrical testing considerations, reliability, shelf
life/solderability retention under aging conditions, and
compatibility with the soldering operation and soldering materials.
Session L
Research
June 25 (Wednesday Afternoon)
Session Organizer & Chairman: Dr. James H. Lindsay, Jr.,
General Motors Research Laboratories, Warren, MI
1 p.m.--Electroplating of Thin Films of Zn-Ni- SiO 2 Composites
onto Steel to Prevent Corrosion & Hydrogen Embrittlement
Professor Branko N. Popov, M.
Ramasu-bramanian & R. E. White, University of South Carolina,
Columbia, SC, & K. S. Chen, Sandia National Laboratories,
Albuquerque, NM
It was found that Zn-Ni-SiO2 composites in-crease the
corrosion resistance by enhancing the kinetic limitations on hydrogen
discharge reaction on deposited composite layers. The hydrogen
permeation rates were evaluated as a function of: (a) alloy
composition; (b) deposition parameters; and (c) concentration of
inert SiO2 particles in the electrolyte. The optimum experimental
conditions for the deposition of Zn-Ni-SiO2 alloy, which provides
good corrosion and hydrogen permeation resistance, will be reported.
1:30 p.m.--Electroless Deposition of Copper on Polyimide
Substrate: Mathematical Model Development & Experimental
Validation
Professor Branko N. Popov, M.
Ramasubramanian, R. E. White & K. S. Chen, University of South
Carolina, Columbia, SC
The technology of electroless copper deposition on a
palladium- catalyzed polymer matrix is being studied. This polymeric
matrix, which has the palladium catalyst dispersed in it, promotes
better adhesion between the metal coating and substrate when compared
to the conventional PdCl 2 /SnCl 2 activation process. The objective
of this effort is to develop a mathematical model for the electroless
copper deposition on these palladium- catalyzed polyimide substrates.
The solution chemistry of the electroless copper bath is studied as a
function of the pH. The mathematical model takes into account (a) the
solution concentration profile in the diffusion layer; (b) mixed
potential theory; (c) mass transfer to the polyimide
substrate-electrolyte interface; and (d) chemical reactions occurring
at the substrate surface. The results obtained from the experiments
carried out for electroless copper deposition under various operating
conditions will be reported. The effect of experimental parameters
such as pH of the electrolyte, catalytic activity of the substrate,
bath temperature, and concentration ratio of the reducing agent and
copper ion concentration on the rate of the metal deposition, will be
discussed.
2 p.m.--A Model of Copper Electrodeposition from Cyanide
Electrolyte, Part II--Current Distribution on a Disk Electrode (AESF
Project #91)
David A. Dudek & Professor Peter S.
Fedkiw, Department of Chemical Engineering, North Carolina University
Raleigh, NC
In previous work, we developed a theoretical model of
copper deposition from cyanide electrolyte on a planar electrode to
provide quantitative framework for investigating the deposition
mechanism. We now extend this model to the disk electrode, which has
an inherently non-uniform current distribution. In this paper, we
present results from the model that describes mass transport by
diffusion and migration of all complexes formed by cuprous and
cyanide (CuCN aq , Cu(CN)2 - , Cu(CN)3--, and Cu(CN)4--- ). The
results investigate the effects of varying solution composition (pH
and stoichiometric con-centrations of CuCN, NaCN, Na2CO3 ) and
electrochemical constants (exchange current density, transfer
coefficients) on current distribution, electrode potential, and
species concentrations at the electrode surface. This work is part of
a larger program that aims to find bath formulations with-out cyanide
that yield current distributions of similar uniformity to that
obtained in cyanide plating baths.
2:30 p.m.--Leveling Performance of Bright D-C or
Pulse-Electrodeposited Coatings as a Criterion of the Property
Estimation (AESF Research Project 97)
Dr. Mois Aroyo & N. Tzonev, Technical
University, Department of Chemistry, Sofia, Bulgaria
In its essence, the current work is based on the thesis
that those d-c or pulse plating parameters and hydrodynamic
conditions at which a maximum value of leveling power is obtained can
unambiguously define the regime of electrodeposition of high quality
metal coatings. In order to sustain this argument, we examine the
role of a number of factors for the crystallization mechanism and
leveling performance of electrodeposited metal coatings: Pulse
frequency, cathodic polarization, diffusion and adsorption of
brightener species.
The leveling performance of nickel coatings, which have been d-c or
pulse-deposited from Watts and sulfamate electrolytes containing
brighteners and a hydrodynamically active agent, are given. The
leveling power dependence on pulse frequency has been established
under different hydrodynamical conditions of rotation and/ or
vibration of the disk electrode. Theoretical modeling considerations
regarding the adsorption- diffusion mechanism of leveling in
low-frequency pulse plating with brightener additives are given, too.
The electrochemical porosity measurements performed for these
deposits have proven the existing correlation between leveling
performance and coating properties.
3 p.m.--Codeposition of Copper & Tin from Sulfate Solutions
Involving Surface-Active Substances
Dr. Professor Arvydas Survila, Dr. Zenius
Mochus & Dr. Ona Galdikiene (now deceased), Institute of
Chemistry, Vilnius, Lithuania
The sequence of partial electrochemical processes was
established in solutions involving Cu (II), Sn (II), Laprol 2402-C
(co-polymer of ethene and propene oxides) and other surface-active
substances. While increasing the cathodic polarization, the
electroreduction of copper, tin, and evaluation of hydrogen proceeds.
Laprol 2402-C acts as an inhibitor because of its adsorption in the
certain range of potentials where the deep minimum on voltammograms
arises. The so-called "reverse peaks" are observed with reverse
potential scan as a result of the variations of phase composition of
the deposits with electrode potential. Adsorption phenomena are
responsible for current oscillations taking part in the region where
the transition from active to passive steady state is possible.
3:30 p.m.--Process Optimization & Pollution Prevention via
OP2EP-Advisor
J.P. Gong, K.Q. Luo & Prof. Yinlun
Huang, Wayne State University, Detroit, MI
Process optimization is a necessary step in effective
pollution prevention (P2) in a plating plant. The optimization
requires a comprehensive evaluation of process design and operational
strategies. In the current work, a computer-aided tool, namely
OP2EP-Advisor, is developed. This Windows®- based tool integrates
various process models and engineers' experience, and is capable of
identifying the bottleneck of waste reduction and providing valuable
decisions on production optimization and P2. The practicality of the
tool is demonstrated by optimizing a cleaning/rinsing system. The
optimization leads to a significant reduction of chemical and water
usage and an improvement of cleaning and rinsing efficiency, thereby
effectively minimizing wastes.
4 p.m.--Computational Evaluation of Influence on Major Factors of
Process of an Electrodeposition on Distribution of a Current in a
Loading of a Drum
Illia Andreev & Ganna Megevich, Kazan
State Technological University, Russia
This paper is a consideration of methods and outcomes of
calculations of distribution of a current on the cathode of a mesh
with mutually perpendicular electrodes.
Session M
Zinc & Cadmium Processes
June 26 (Thursday Morning)
Session Organizer & Chairman: Douglas Lay, CEF, Taskem, Inc.,
Cleveland, OH
8 a.m.--Elimination of Solution Growth in Chloride Zinc
Solutions
Richard Painter, Pavco, Inc., Cleveland,
OH
Solution growth is a perennial problem with chloride zinc
electrolytes. The surfactants used in chloride zinc plating affect
surface tension so that the volume of rinse water dragged into the
bath is more than the volume of bath dragged out. The excess solution
is typically decanted and waste-treated. The economic pressure on
platers has resulted in several strategies to eliminate solution
growth. This paper will look at the use of evaporators, higher
solution temperatures, and inert anodes in order to abate solution
growth. The cost advantages of stopping solution growth will be
discussed.
8:30 a.m.--Change in Surface Color of the Chromated Film Under
High Humidity Environment
Yon-Kyun Song, Hyung-Joon Kim, Pohang Iron
and Steel Company, Kyungbuk, Korea
Chromate conversion coatings are widely used for
enhancement of corrosion resistance. The color of the chromated film
on galvanized steel sheet depends on the solution composition. One of
the common colors is blue. The color of the chromated film on
electrogalvanized sheet is changed from blue to black in a high
humidity environment. Even though the quality of chromated films is
not deteriorated by color changes, the end user complained about its
appearance. In this study, to help identify the cause of the color
changes from blue to black, the chemical state of the chromium and
zinc were investigated by using the electrical analysis tools (SEM,
SAM, XPS and XRD). A new chromating solution was developed to reduce
the color change of the chromated film in a high humidity
environment.
9 a.m.--The Role of Lubricant for Lubricant-Coated Steel Sheet
Chan-Sup Park & Joon-Hyung Jo, Pohang
Iron and Steel Company, Pohang, Korea
Lubricating resin (mainly composed of resin co-polymer,
hardener, lubricant, and colloidal silica, etc.) for zinc-coated
steel sheet was developed for the application at in-line. Adding the
lubricant to the resin is important to control the quality of the
lubricant-coated steel sheet. Its quality was characterized with
respect to kinds, melting temperature, amount and mixing ration of
lubricant. Pretreatment, baking temperature and kinds of resin were
also taken into account to evaluate the quality properties.
9:30 a.m.--A New Alkaline Zinc-Nickel Electrolyte
Victor G. Roev & R. A. Kaidrikov, Kazan
State Technological University, Kazan, Russian Federation
For many years, electrodeposited zinc coatings have found
extensive used for the corrosion protection of steel. The processes
for plating from zincate electrolytes are very useful in the
auto-mobile industry. On the other hand, the alkaline zinc-nickel
(12-13% Ni) alloy plating is attractive in order to obtain the best
quality of coatings with the best corrosion resistance. In this work,
some results relating to the study of a new zinc-nickel (12-13% Ni)
zincate-type electrolyte will be described. Results show that Zn-Ni
alloy coatings have an almost constant thickness over intricate
shapes combined with an almost constant nickel content. Research and
performance data will be presented.
10 a.m.--Corrosion of Zn in Chromating Solution: The Composition
Model of Diffusion Layer
Professor R. Sarmaitis, Dr. V. Dikinis, Dr.
V. Rezaite Institute of Chemistry, Vilnius, Lithuania
The concentration profiles of the components of the
chromating solution were calculated on the basis of mass transfer
model, taking into account the dynamic chemical equilibriums. The
data of the composition model of the diffusion layer alongside the
analysis of the solubility of the series of Cr (III), Zn (II) and Cu
(II) compounds allowed the determination of the composition of
conversion coatings formed on the surface of Zn in the chromating
solutions. The presented data led to the conclusion that anions of
inorganic and organic acids facilitate the Zn corrosion in chromating
solution as a result of the easy contact of the solution components
with the surface and contributing to the reduction of Cr(IV) to Cr
(III).
Session N
Chemical Milling
June 26 (Thursday Morning)
Session Organizer & Chairman: Thomas Foulds, Boeing
Commercial Airplane Group, Seattle, WA
8 a.m.--Thiosulfate--An Unwelcome Member in the Aluminum Chemical
Milling Bath
T. D. Brown & L. E. Bruce, McDonnell
Douglas, Long Beach, CA
A major problem of the 104,400-gal type 1 aluminum
chemical milling tank was surface roughness with etch rate decline.
The tank, DC-05, was installed in 1988 when aerospace was entering a
major retrenchment. Preliminary investigation revealed that the root
cause of the problem was that DC-05 was not operating at peak
capacity. Ten-thousand gallons of sulfur concentrate was added during
the year which, with the initial charge, equaled 20 tons of sulfur in
the bath, with short-term improvements. By 1989, analyses of the bath
showed that the N 1 (caustic concentration) and N 2 (aluminum
concentration) were in range, but the sulfur concentration was
surprisingly low. Once again, the tank produced rough surfaces and a
slow etch rate. We began to question adding more sulfur concentrate.
Laboratory testing found that the best cure was to discard a portion
of the bath and replace with water. The 1991 lab report, LR-15233,
determined the relationship of the chemical milling bath condition
and sodium thiosulfate. DC-05 was drained and refurbished in the
spring of 1996 and the rate/ surface problem appeared again on etched
production parts within a few months. Analyses showed excess
thiosulfate present. This paper will follow the investigations,
testing, findings, and solutions to returning tank DC-05 to proper
operating conditions. We found that while sulfur is good for a
chemical milling bath, when it converts to thiosulfate, the surface
roughness will increase and the etch rate will approach zero.
8:30 a.m.--Effect of Sulfur Components on Surface Roughness from
Aluminum Chemical Mill Etch Tanks
Thomas Foulds, Boeing Commercial Airplane
Group, Renton, WA
In 1996 Boeing replaced a 1950s era aluminum chemical
milling shop with a new one in Auburn, WA. At the original Plant 2
location, etch tanks lasted three weeks before dumping because of a
low etch rate or because the tank began producing rough 7075 alloy
fillets. Chem-mill etch tanks normally work this way. The larger
tanks at Auburn lasted a little longer, but failed for different
reasons. They had to be dumped because of end-grain pitting or a very
rough surface on the flat portion of a 2024 alloy pocket. This paper
relates the different failure mode to the effect of sulfur compounds
(sulfite, sulfate, thiosulfate and polysulfides) formed in the etch
tank from sodium sulfide. Sodium sulfide is a standard Type II etch
solution ingredient.
9 a.m.--Chemical Milling Bath Caustic Recycling & Aluminum
By-Product Recovery Using Diffusion Dialysis
Mark Jaffari, Malek, Inc., San Diego, CA
This paper describes the successful application of
diffusion dialysis to enhance efficient caustic regeneration and
high- quality aluminum by-product recovery. Advantages of this
approach over traditional methods include more precise chemical
milling bath control and lower energy requirements, as well as
production of a more valuable aluminum by-product.
9:30 a.m.--Comparison of Chemical Maintenance Methods for
Nitric/HF Milling Solutions
Dr. Thomas Hanlon, United Technologies
Research Center, East Hartford, CT & Peter Johnson, Sikorsky
Aircraft, Stratford, CT
Chemistry control methods for nitric/hydrofluoric milling
solutions are compared. Standard methods add acids weekly, based on
analyses. This necessitates periodic decanting to maintain titanium
below 32 gL. Production interruptions and inherent EH&S risks of
transferring large acid volumes are disadvantageous. Feed and bleed
is another control method. Advantages are level maintenance of
acid/metal concentrations and steady, low-volume waste flow. Third
control method treats a side stream using ion exchange, partially
removing metal while discarding proportionally lower acid volumes.
The advertised result is constant chemistry with no process
stop-pages. In practice, more frequent solution analyses/ additions
and periodic decanting are required.
10 a.m.--Quality Improvement of the Chemical Milling Process
Bruce Griffin, McDonnell Douglas, St. Louis,
MO
The chemical milling process is used extensively in the
manufacture of aluminum, titanium, and steel components for the
aerospace industry. The process is employed to reduce airframe weight
by selective and controlled metal dissolution from airframe
components. When chemically milled parts are assembled, however,
part-to-part interference frequently occurs. This situation suggests
that current standards for part quality are not sufficient.
Quality control techniques currently used in the chemical milling
process are based on the concept of zero defects. Process output that
falls within a specified engineering tolerance is acceptable and is
shipped to the customer. Components or parts that are acceptable by
the zero defects philosophy may actually require rework. As a result,
the parts cause a loss to the customer. This study identified
chem-mill undercut ratio as the process characteristic with the
greatest effect on chem-mill part quality.
This study demonstrates application of quality engineering techniques
to the chemical milling process for improvement of the quality of
chemically milled parts. Quality engineering tools demonstrated
include Pareto, Cause and Effect Diagrams, Taguchi/Design of
Experiment Techniques, Regression Analysis of experiment data, and
Tauchi Loss Function.
10:30 a.m.--Comparison of Water-based Maskants to Solvent-based
Maskants with Recovery
Jim Wichman, AC Products, Placenta, CA
Traditional chemical milling maskants require significant
usage of toluene, xylene and perchloroethylene, etc., for their
application to aircraft fuselage skins and structural components.
They must be used in conjunction with a solvent recovery system to
comply with current and future air quality regulations. Water-based
chemical milling maskants provide compliance to air quality
regulations without the use of a solvent recovery system. This paper
discusses the advantages and disadvantages for each method of
compliance.