Hi Jac,
I am just wondering how your selective stripping is working?Probably you are
using selective masking ( photoresist) to protect the areas destignated for
reflow.What kind of photoresist are you using and what about overlaping
between tin-lead stripped pattern and solder mask pattern?
In the past we made trials and we faced the following problems:
1) leaking of tin-lead stripping solution along lines.This resulted non
clear boundary between the sections that were destignated for reflow and
those destignated to be covered by solder mask.
2) as result of the previous,we got exposed copper ar the boundary of the
"reflow side" and tin-lead on the "solder mask" side.
Regards

Edward Szpruch
Eltek , Manager of Process Engineering
P.O.Box 159 ; 49101 Petah Tikva Israel
Tel  ++972 3 9395050 , Fax  ++972 3 9309581
e-mail   [log in to unmask]

> -----Original Message-----
> From: Jac Kroeker [SMTP:[log in to unmask]]
> Sent: ג ספטמבר 14 1999 22:08
> To:   [log in to unmask]
> Subject:      Re: [TN] Surface finishing -Reply
> 
> Hi Ron and Phil;
> We do a selective tin lead strip. This allows us to put solder mask on
> bare
> copper, eliminating the problem of the wrinkling mask. Plating the
> tin/lead
> also increases the control of the amount of tin/lead remaining on the
> pads.
> Result - almost flat smd pads.
> Jac Kroeker
> 
> At 08:57 AM 09/14/1999 -0700, you wrote:
> >Hi Phil,
> >I remember the days at Burroughs with the tin lead plate and
> >IR fuse. The only draw back to tin lead plate and fuse, is
> >that you are putting solder mask over the fused solder,
> >which has a tendancy to wrinkle and possibly flake off during
> >or after any subsequent soldering operation.
> >Ron Hayashi
> >
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