Hi, All

We got a PCB shop to fabricate our new designed board. All issues are solved
except the solder mask. The SM appeared to be milky white after went through
electroless Ni immersion Au process. Usually delamination would occurred and
SM materials looks kind of soft. We suspect SM materials (coat Brothers)
giving problem, so we try another SM materials (Taiyo Ink). Trial run with
full Cu panel without pattern yield positive result. However when real etch
panel is tested, the same issue occurred.

After I went through their process flow and found something strange. The
electroless Ni took 40 - 60 minutes to achieve 130 u" and 20 -30 minutes for
Immersion Au. The bath is having 16g/l Ni and operate at 89 deg. C.

At this stage , we think the long exposure time that cause the SM failure.
I have a question that I would like to know is whether there is something
wrong with the bath and what is the typical time to achieve the same Ni/Au
thickness.

could someone shed some light over this issue. Any comments is truly
welcome.

Chong Chee-leong
Agilent Technologies

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