At 06:52 PM 6/11/97 -0500, you wrote:
>I would like to take an informal survey of BGA pad design styles.
>
>
>1.   Are you using soldermask defined pads or pads that are clear of 
>mask? (by soldermask defined pads I mean, the copper land is larger 
>than the soldermask opening allowing the soldermask to define the BGA 
>attachment site)
>WE DO NOT USE SOLDERMASK DEFINED PADS.

>2. If you use Soldermask defined pads do you allow the soldermask to 
>fall off the pad (misregistration)?   If not how much registration do 
>you allow for to keep the soldermask on the pad?
>
>3.  Do you experience problems with mask lifting during rework?
>YES WE DO HAVE MASK LIFTING.  SOME OF IT IS IN AREAS WHERE WE MASK AREAS
LESS THAN .005".  WE ARE CONSIDERING REMOVING MASK UNDER OUR BGA PARTS.

>
>Thanks for the help..looking forward to the discussion.
>
>
>
>Douglas Jeffery
>Electrotek,Inc.
>
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