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Reply To: | TechNet E-Mail Forum. |
Date: | Mon, 12 Jun 2000 11:20:32 +0100 |
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> ----------
> From: Geoff Layhe
> Sent: 12 June 2000 09:47
> To: [log in to unmask]
> Subject: RE: [TN] Wrinkles in copper foil
>
> Jan,
> Just a few quick thoughts on wrinkled copper.
>
> It can be due to different expansion rates of the material on either side
> of the copper, i.e. the laminate and the separator plates. If this is your
> problem it will usually be worse on high layer count boards, in the middle
> of a stack and on larger panel sizes.
> Try different separator plates, aluminium may work better than steel, use
> a release film in contact with the copper, or release coated aluminium
> separators this will allow the copper to expand and contract easier.
>
> Have you tried a lower pressure?
>
> Is your copper foil tooled? if so does the wrinkling occur around the
> tooling holes? Maybe the tooling holes are not quite in the the right
> position or are too tight on the copper and the copper has to be
> "stretched" on them.
>
> Hope the ideas help
>
> Geoff Layhe
> www.lamar-uk.co.uk.
> ----------
> From: Jan Thuesen[SMTP:[log in to unmask]]
> Reply To: [log in to unmask]
> Sent: 09 June 2000 10:33
> To: [log in to unmask]
> Subject: [TN] Wrinkles in copper foil
>
> Dear Technetters,
> we have been seeing increasingly problems with wrinkles in
> outerlayer copper foil on certain jobs.
> The wrinkles are coming from the press-lamination of multilayers.
>
> We have tried different things to minimize the problem like
> optimising heat up and cool down time and temperature, different types of
> presspads, awareness at lay up, adding copper areas to the underlying
> layers, different prepregstyles amo.
>
> If any of you have some additional inputs to the cause of the
> problems, we will be very interested in hearing from you.
>
> With best regards
>
> Jan Thuesen
>
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