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Article: Fine lines in high yield (Part LXXIX) problems with residual, excess copper in print/etch and tent/etch processes (Part B). (Tech Talk).
- Article from:
- CircuiTree
- Article date:
- April 1, 2002
- Author:
CopyrightCOPYRIGHT 2002 BNP Media. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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This column is the second of a series on the subject of excess copper, and deals with defect causes related to lamination, exposure and phototooling.
Lamination Problems Leading to Excess Copper
Excessive lamination temperature can cause thermal cure of some resists and cause difficulties in developing cleanly. Excess copper could be massive with higher levels near the leading edge of the panel. Check laminator roll temperature and board exit temperature.
If panels are stacked immediately after lamination, they remain hot for a long time, which will aggravate a thermal curing problem due to excessive lamination temperature.
If resist ...