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 ************************************************************************** * * TechNet mail list is provided as a service by IPC using SmartList v3.05 * ************************************************************************** * * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ************************************************************************** * *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************