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Date: | Wed, 24 Jan 96 8:50:35 EST |
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Rick,
The best method to eliminate shorts is to perform "root causes analysis". In
other words identify where the short occurred. There are three primary tools
used today: CAM Design Analysis, Automatic Optical Inspection, and Electrical
Test. These may be obvious but are the best tools today to ensure high yields.
A Design Analysis program can verify netlists and summarize design spacing
values. An optical inspection systems can optically compare the bare board
against the orignal design and highlight in-process defects. This tool can be
used throughout the process to inspect: the master phototool, the working photo-
tool, the developed resist image, and the post etch panel. As the final
gateway, electrical test is used to prevent any board with a short being sent
to a customer. Using these tools can help eliminate defects only if corrective
action is taken to eliminate the cause of the defect.
George Murray
Gerber Systems
Rick wrote:
> I have been tasked to eliminate the defect of shorts on PWB's. Other than the
> obvious etch defects, what are some causes of shorts that other companies have
> seen ? Could the raw material be part of the problem ? Could the defect be
> "buried via" related ? I would appreciate any inputs or thoughts on the
> subject.
>
> Thanks in advance,
>
> Rick Haynes
> Process Engineer
> Texas Instruments
> e-mail [log in to unmask]
> phone 512/250-7823
>
>
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