I am surprised to hear the exposure step has a correction to the degree you've implied. This is interesting to me. Would you consider sharing your finding with the net. I am interesting in what step you have found to be the best. You can express you data in % relative to the other 
steps in lieu of to the population tested. This way you don't have to share your internal yields with the world,  I would like to run a correlative study of my own. We use Dynachem HG and GA resist. What do you use?

Our studies have concluded that the major cause of short and opens are directly related to the method and frequency by the which the printers clean there phototool ( A/W ). In other words we only have problems when we find operators not wiping down there film. Another key finding is the cleanliness of the room. 

Ed Cosper

----------
From:  indal[SMTP:[log in to unmask]]
Sent:  Friday, April 11, 1997 11:29 PM
To:  [log in to unmask]
Subject:  OPENS AND SHORTS



During PCB fabrication opens and shorts are major defects observed at ET. we conducted a DOE on a specific partnumber and found that every step change at primary imaging has a great degree of corrilation to Opens and Shorts. However the photoresist manufacturer specs are very wide 5 to 8 SST or 12 to 18 RST.Why are we finding a huge quality difference inside the specification ? How are you taking care of the above? 
PLEASE COMMENT AT [log in to unmask]

***************************************************************************
* 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]      *
***************************************************************************


***************************************************************************
* 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]      *
***************************************************************************