Where the
world gathers for metal finishing
Q&As since 1989


-----

Converting lead frames from Gold to Silver plating

1999

Dear Sir,

We are glad to introduce ourselves to you. We are a Romanian company producing CMOS integrated IC's and optoelectronic devices-LED technology (LED diodes and LED displays). Our company began the activity at the end of the year 1982 based on a S.G.S. Italy license for assembling of IC's in PDIP and ceramic packages (8-40 leads).

For the deposition of Gold (Au) on the pad of lead frames we have an equipment type Carousel MK II, Mode 2 "with pulse plater" produced by S.G. Owen ltd, Northampton England.

The actual process of deposition is selective gold plating of lead frames.

The basic material of lead frames is Kovar (Fe-53%, Ni-29%, Co-17%, Mn-0,50%, 5 max; C-0,06% max, Si-0,20% max, Al-0,10% max, Mg-0,1% max, Zr-0,10% max, Ti 0,16% max)
or Fe-Ni-Alloy42 (Fe-Balance, Ni-41%, Co-0,50% max, Mn 0,80% max, C-0,05% max, Si-0,30%max, Al-0,10% max, S-0,025% max, P-0,025% max, Cr-0,10% max)

For the selective gold plating the parameters of the process are:

1. Current density optimum/6A/dm2
2. Voltage 5,4 V
3. Solution pH 5,75
4. Solution temperature 72 C
5. Shaking continuous
6. Filtering with filtering
7. Pulse plating 3 ms "ON"//1 ms "OF".
8. Potassium gold cyanide 8 g/lt.

Now, due to economical reason we wish to change the process and to adapt the equipment to Silver plating deposition (basic material: Kovar, Alloy42 or Copper). For this reason, we kindly, ask you to assist us and recommend the adequate chemicals and the conditions of the new process and eventually some changes for the equipment.

We thank you in advance for your assistance and we are waiting your soonest answer.

MICROELECTRONICA S.A.
- Ilfov, Romania