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October 2000

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Subject:
From:
Per Viklund <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 5 Oct 2000 10:03:58 +0200
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Hello Tech-Netters

I have a question regarding manufacturing output for solder paste stencil to
Ceramic BGAs with non collapsing balls.

For large BGA's (300+ pins) with non collapsing balls, there are a few
issues with soldering onto normal circuitboards.
The component is large and the board is seldom perfectly flat.
Therefore, you may end up with some balls not fully contacting the
solderpaste with a bad joint as result.

I've learned that one method to solve this is to have a thicker layer of
solderpaste to this component and that the
manufacturers can add thickness  selectively to the solder paste stencil.
In this case, HOW should one best describe this in the CAD output?
Would the manufacturer prefere a separate film with a filled area
representing the component or are there other means that are better?

Kind regards

Per Viklund

Dansk Data Elektronik AS / DDE Sverige AB / DDE USA Inc.
mailto:[log in to unmask]
http://www.dde-eda.com

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