Phil,
Plasma cleaning of finished boards is rather problematic : as I understood
your reply,the plasma cleaning sequence should be set strong enough to
remove thin layer of residues from PISM developing solution ( if it is
present ) but without effecting PISM on the rest of the board.
We made some trials in the past and I might say,this is very tricky way,
since PISM on the board under plasma condition was prone to some extend of
discolloration.
The main issue is, of course, possitive detection of such contamination.
We made cleanless tests ( by Omegameter) without clear results, since this
test is detecting ionic contamination and not organic. At the end we
sacrified some boards for wave soldering ( we do not possibility to print
solder paste).
Bill,good luck
Edward
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: Crepeau, Phil [SMTP:[log in to unmask]]
> Sent: в аевеси 07 2001 16:30
> To: [log in to unmask]
> Subject: Re: [TN] Contamination Concern after Strip
>
> hi,
>
> you might look into plasma etching. if your board fabricator uses this
> process for hole cleaning, they may be able to do this for you.
> cleanliness could be determined by running some wire bond tests on the
> panel before you start the real wire bonding.
>
> phil
>
> -----Original Message-----
> From: Bill Christoffel [mailto:[log in to unmask]]
> Sent: Tuesday, August 07, 2001 6:04 AM
> To: [log in to unmask]
> Subject: [TN] Contamination Concern after Strip
>
>
> Input Needed !
>
> We currently use a board that is designed for gold ball bonding (COB)
> and have specified electroplated gold as the top metal layer. This
> board also uses a Tayio solder mask material that is flood coated over
> the top, including the gold pads then photo imaged/etched. to expose
> specific gold pads for wire bonding. My concern is that the solder
> mask may be leaving some type of contamination on the bonding pads. If
> so, I'm looking for recommendations on how to verify cleanliness, other
> than ionically (which we do) and how to remove any contamination.
>
>
> Thanks,
>
> Bill C.
>
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