Generally, it is best to have a dedicated plating cell for panel
plating. Keep anode-to-cathode distance as great as possible (12 inches
is good), have very good agitation. Plenty anodes, but you will find an
A:C area ratio of close to 1:1 or 1.5:1 (as opposed to the standard of
2:1) will work best to prevent copper buildup in solution. I believe a
high acid/low Cu solution is preferred (it's been awhile). Additional
theiving around the part will most likely be necessary but much can be
done with shields in the solution. A standard part size is helpful.
Your will find that all of the mechanical means of controlling surface
thickness have far greater effect than the chemistry.
For horizontal electro-plating, contact Schering in State College. I
believe they are the experts for that.
Regarding the tent and etch part, starting with half ounce Cu would of
course make good sense. Cleanliness during resist coat/lamination and
registration for imaging are essential, read critical. A well-tuned-in
etching process makes good sense, too. If the pads are so small, there
are alternative processes to dry film tenting - such as electrodeposited
resist. An ED resist completely coats the walls of the plated vias. A
positive-acting ED resist means that it develops off where it sees UV
light and does not where it does not - such as in the vias. I have seen
grossly misregistered parts, such that the pad is only across half the
hole, yet the plating in the hole remained completely intact after
etching - because it was protected by an ED resist.
And, yes, 5/5 should be quite doable and so should 2/2, but not without
well-tuned processes and a clean operation.
Patty
[log in to unmask]
----------
From: Joel Fillion
To: [log in to unmask]
Subject: Re: [TN] Plating
Date: Wednesday, July 22, 1998 11:51AM
Hello Dick,
It is definitely possible. However, it is extremely important to
properly
control plating parameters that effect plating distribution. Also,
depending on how well you control the process, you may have to use
excessive border around the panel to isolate the circuits from your high
current density area (robbers).
Good Luck
At 11:13 AM 7/22/98 EDT, you wrote:
>Technetters
>
> Is it possible to produce 5/5 technology with a panel plate tent and
etch
> process ? Also, what are the strengths and weaknesses of horizontal
plating
>processes ? Can anyone provide me with info on horizontal electro
plating ?
> Thanks for your help
>
>Dick Desrosiers
>
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