Ed, I would have to agree with your statement regarding exposure steps and opens/shorts. It has been my experience as well that cleanliness in the imaging room is the most critical part of the process, in terms of opens and shorts. Variation within the recommended exposure range should have little or no effect on defects. An extremely high or low step (say, two or more steps above or below the normal range) could cause problems. Too low of an exposure would not fully polymerize the resist, which could then lift in later processes. Too high could make the resist brittle, causing cracks, or allowing the resist to flake off. I would not be concerned with a variation within the typical three step range (usually 8 to 10 resist, or 9 to 11 copper, although this varies from film to film). I would also be interested in seeing the data from this study relating exposure changes to defects. Mark Dowding Regional Technical Specialist Morton Products Insulectro *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************