Hello Robert:

I assume you are talking about preclean for electroplating. 
I think the best way to check the performance of the cleaning solution is to run some test coupons to get weight loss. You could prepared test coupons same as your production and let some test coupons go through the whole preclean stage and the others only hit acid cleaning. Then set your SPC limit accordingly based on the performance. The titration you do is  to check the acid content and we assume the surfactant is properly mixed well by the ratio.  But that can be off sometime.  

The amount of copper need to be removed is really determined by the upstream process. The thickness and fine structure of the PTH and film you are using. The bottom line is to keep integrity of the PTH and microrough the surface but not micropolish. 
----------
From: 	Robert Peterson[SMTP:[log in to unmask]]
Sent: 	Monday, March 10, 1997 11:47 AM
To: 	[log in to unmask]
Subject: 	FAB:Preclean parameters


I am trying to determine reasonable parameters in my pre plate cleaning 
operation.
The first thing I need is a way to check the performance of the cleaning 
solution.  We recently had a bath go bad early but it met all the tests we 
were doing.  We check with a titration method recommended by the vendor as 
well as a specific gravity check.
The other thing I would like to know is what is a reasonable amount of copper 
to remove during a micro-etch process.  Also what would be the maximum that 
would be expected to be removed.  We currently run between 25 and 50 
microinches per minute with a two minute cycle.

Any suggestions would be greatly appreciated.

Bob Peterson 

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