Metal finishing Q&As since 1989
-----
Rough gold plated features
Q. I work for MEMS company in Richmond, CA. I am trying to plate gold features on wafers for the company that I work for. I am plating gold on gold. My plating solution is of the sulfite classification, TG25E-RTU from Technic, Inc. Recently I am having problems with my plated features being rough. The parameters that I used were a 17mA current for a plating area of 6.9cm^2. I plate for about 30 minutes to get approximately 5um features. I plate on wafers that are patterned with photoresist. My features before were very smooth and soft. The bath is brand new too from the maker. Could someone tell me why I am getting the rough features? Thanks.
KaoSio Saechao- Richmond, California, USA
2005
A. Rough deposits are due to suspended impurities in solution, check filters, replace cartridges if required.
Peethambaram Parthasarathy- Surface Chem Finishers, Bangalore, India
2005
A. Kao Sio,
To plate gold over gold up to 500 microns with out roughness
(provided all plating parameters are maintained) there are products available in the market. Engold HSD (High Speed deposition) manufactured by Metalore earlier known as Engelhard will give you 5 microns thickness in 8 minutes.
Regards
T.K. Mohan
plating process supplier - Mumbai, India
2005
April 19, 2012
A. Hi kaosio,
1. Please check your pre treatment process if it is still good to clean the base material being process
2. Please check the rinses you use if is contaminated (e.g., pH and conductivity)
3. please check your filtration system
4. To make sure to eliminate the rough gold problems, add acid cleaning into your pretreatment before plating (for labscale purposes).
Hope these will help you to solve your problem.
regards,
- philippines
Q. Hi there.
My production line too is facing the rough gold defect. Can a better filter system or change of chemicals improve the condition? It is preferable if any reference is provided. Thank you.
WC Chong
circuit manufacturing - Penang, Malaysia
February 3, 2012
A. Hello all.
I, too encountered roughness issues, as we plate 30 mA for 4 hours. I also checked the normal things ,filtration and specifically bath parameters. I am not familiar with your chemistry but I will relate to you my situation. Upon examination under a microscope, the roughness I saw were actually nodules, which grew larger as plating progressed. This gold solution is an old Technic bath, E-56. The brighteners I discovered were Arsenic-based and they break down over time, more-so as plating times increased.
I added brightener more frequently in smaller doses and noticed as the gold concentration decreased the incidence and size of the nodules decreased to a point of no existence.
Hope this helps.
Regards
- Toronto, Ont, Canada
February 7, 2012
Q, A, or Comment on THIS thread -or- Start a NEW Thread