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November 1998

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Subject:
From:
Paul Gould <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Wed, 11 Nov 1998 11:41:52 -0000
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text/plain
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text/plain (73 lines)
Francis,

I have seen this resist lift problem myself. You need a robust film
for gold plating at least 2mils thick, not the standard primary
imaging film.

You mentioned over exposing the film which is the last thing you want
to do. We found this made matters worse.  The release of hydrogen at
the cathode affects the resist by polymerising it further. It becomes
brittle, loses adhesion and lifts. We found the best result was to
underexpose and plate straight away. Even exposure to daylight should
be avoided after developing the film.

If you are pattern plating with copper then you will need to change to
panel plate and apply the resist for the gold pattern only. This does
increase the etch factor but prevents track spreading because the
copper plating cycle weakens the resist.

Hope this helps
Paul Gould
Teknacron Circuits Ltd
UK
www.teknacron.com



-----Original Message-----
From: Francis Lai <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: 06 November 1998 22:45
Subject: [TN] Problem in Gold Plating


>I work in gold plating. We are using electrolytic gold plating.
>
>It is pattern plating. However the gold leaks underneath the dry
film.
>
>As a result the pattern is fatter after the dry film is removed.
>
>We develop the pattern dry film and thenn hardenn the dry film by
>
>exposing under UV light again. But still it leaks underneath the dry
>
>film. Could any one help ?
>
>WE also want to set up a pulse plating bath ourselves. Could any
>
>one give us some information onn how to start ?
>
>Thanks in advance!!!!!!!!
>
>my e-mail : [log in to unmask] ( Please do not send graphics,
this
>                                        is text base)
>
>Thanks again
>
>Francis
>

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