We cleaned the boards with IPA which should have removed any flux residue
from the HASL process.  The cleaning had no effect on the adhesive bonding
to the PCB.

Interestingly enough we are seeing good adhesion and very poor adhesion on
the same PCB.  The PCB is about 8"x8" and has 120 part glued down.  The
parts are SOIC-8, SOT23, and 1206 resistors and caps.  The problem is seen
with every part type.

Our thought right now is that the solder mask (SR1010G) is not fully cured.
 However the PCB fabricator insists this is not the problem because
non-cured mask would be evident by mask defects during HASL process.

What is polyglycol and where does it come from?

Cory


At 05:19 PM 7/2/99 EDT, you wrote:
>In a message dated 07/02/1999 12:31:46 PM US Eastern Standard Time,
>[log in to unmask] writes:
>
>> We have investigated the PCB fabricators process, the adhesive
>>  curing process and the adhesive.  Does anyone have any advice?
>
>And what were the results?  You describe a problem adhering to the mask.  The
>SR1010 series is fairly porous and may absorb LOTS of stuff from the HASL
>process.  My guess is that you have residual polyglycol residues on the
>surface and absorbed into the near surface.  This changes the nature of the
>mask.  Polyglycols are frequently used as surfactant agents and are
>"slippery".
>
>Doug Pauls
>CSL
>
>