I believe that the copper is still on the board at this point which will block
the light from either side.   Light through the board applies for secondary
imaging resist, but not primary imaging.
Ken Bridges - Morton

>>> Hodgson, Pete <[log in to unmask]> 09/09/96 08:22am >>>

I would suggest that it is not so much a lamination issue as it is an   
exposure issue.  Keep in mind that with double-sided material, light may   
penetrate the laminate and in essence, expose your panel from both
sides    if you are not using a UV-block enhanced laminate.  In a
multilayer,    there are typically power and ground planes which would
block any light    from coming through the panel, thus lessening your
actual exposure of the    laminate.  We found this an especially
perplexing problem a couple years    ago when we were first working
with LPI Solder Mask.


 ----------
From:  TechNet-request[SMTP:[log in to unmask]]
Sent:  Monday, September 09, 1996 6:10 PM
To:  technet
Subject:  Disscussion on seepage /resist lifting problem in 4/4mil and   
5/5 miljobs..



    with respect to above mentioned problem i wud like to clarify that    the
said defect is being noticed only in ML boards.The said problem is not
noticed to such an extent in DOUBLE SIDED RIGID boards for the same
complexity of the Product. Therefore we suspect strongly the ML   
lamination process as a POTENTIAL CAUSE.Could any one throw some
light on this

   


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