At 10:08 AM 10/21/2009, Paul Reid wrote: >Hi Ian, > >Yes. > >We have seen adhesive failure between glass bundles (not individual >fibers) and C-stage epoxy. It is rare but it happens. not so rare with some reason systems esp if related CE (that will remain nameless to keep it collegial here). :-) >If the >delamination is between the B-stage and the C-stage we usually blame the >B-stage. On occasion we get adhesive delamination between the C-stage >and the copper foil particularly with reverse bearing foils. > > > >Sincerely, >Paul Reid > >Program Coordinator >PWB Interconnect Solutions Inc. >235 Stafford Rd., West, Unit 103 >Nepean, Ontario >Canada, K2H 9C1 >613 596 4244 ext. 229 >Skype paul_reid_pwb >[log in to unmask] <mailto:[log in to unmask]> > > >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of Ian Hanna >Sent: October 21, 2009 11:44 AM >To: [log in to unmask] >Subject: Re: [TN] delamination signatures > >Hi Paul -- there could be adhesive failure, or delamination, in c-stage >no? Ian > >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of Paul Reid >Sent: Wednesday, October 21, 2009 9:53 AM >To: [log in to unmask] >Subject: Re: [TN] delamination signatures > >Hi Chris, > >I think that the signatures of material damage should be taken as an >indicator not an absolute for determining root cause. > >I cannot bring myself to call cracks in areas that were never laminated, >adhesive delamination. I can thank my colleague Jason Furlong who, years >ago, said to me "If that area was never laminated how can you call the >crack delamination?" As it stands now I can't call cracks in the middle >of the B or C stage adhesive delamination. For me if the crack does not >follow an internal interface it is "cohesive failure" not adhesive >delamination. > >If we can agree that adhesive failures tend to be a breakdown of an >internal interface, cohesive failure a breakdown of the epoxy system and >crazing a separation between the individual glass fibers and the epoxy >system then these symptoms may give indication of where to look for root >cause. At least this interpretation of failure signature could direct >you to look into areas that would contribute to those types of failures. > >Consider the alternative. If each delamination signature does not narrow >the area of investigation for root cause then one could naively start >with material shelf life and storage, move to lamination (cycle, times, >pressures, platen planarity, heat distribution, etc), go on to drilling >(feeds, speeds, and hit count etc) and proceed through the other 97 >steps of PCB fabrication, (not forgetting oxide coating, cleaning, >rinsing etc.). If that investigation is not fruitful then move on to >design and methods engineering variables like grid size, % resin etc. >You might find out in the end you were using a DICY cured laminate in a >lead/free HDI application and the material damage was cohesive failure. > >There may be hundreds of root causes of material degradation I can think >of at least a hundred. I say - Let the cross section talk to you and >narrow your investigation based on observation and experience. > >Don't forget... when in doubt bake! It doesn't much help but it does >give one reason to hope. > >Sincerely, >Paul Reid > >Program Coordinator >PWB Interconnect Solutions Inc. >235 Stafford Rd., West, Unit 103 >Nepean, Ontario >Canada, K2H 9C1 >613 596 4244 ext. 229 >Skype paul_reid_pwb >[log in to unmask] <mailto:[log in to unmask]> > > >-----Original Message----- >From: TechNet [mailto:[log in to unmask]] On Behalf Of Chris Mahanna >Sent: October 19, 2009 9:24 PM >To: [log in to unmask] >Subject: [TN] delamination signatures > >Hello TN, > >I'm wondering how certain one can be about the root cause of delam. >simply by reading its signature. Our experience is similar to Paul >Reid's (post attached below). One obvious question: what about when it >is both co and adhesive failure? >Are there other features to the signature that are important in >determining primary root cause? > >Chris > >------------------------------------------------------------------------ >------------------ > >My sense is that moisture induced delamination presents as adhesive >delamination that is horizontal cracks that resemble blisters and are >located at a laminated interface (b-stage to c-stage or copper, or along >bundles of glass). It may be that the vapor pressure exerted by trapped >moisture induces a mechanical failure at laminated interfaces. > >Material degradation induced delamination more often presents as >cohesive failure that may exhibit cracks with vertical sections, often >bifurcating and spanning across b-stage and c-stage material, even >through glass bundles, and tend to propagate with sharper angles. This >failure mode appears to be more a chemical degradation of the epoxy >system. > >Sincerely, > >Paul Reid > > >--------------------------------------------------- >Technet Mail List provided as a service by IPC using LISTSERV 15.0 >To unsubscribe, send a message to [log in to unmask] with following text >in >the BODY (NOT the subject field): SIGNOFF Technet >To temporarily halt or (re-start) delivery of Technet send e-mail to >[log in to unmask]: SET Technet NOMAIL or (MAIL) >To receive ONE mailing per day of all the posts: send e-mail to >[log in to unmask]: SET Technet Digest >Search the archives of previous posts at: >http://listserv.ipc.org/archives >Please visit IPC web site >http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 >ext.2815 >----------------------------------------------------- > >--------------------------------------------------- >Technet Mail List provided as a service by IPC using LISTSERV 15.0 >To unsubscribe, send a message to [log in to unmask] with following text >in >the BODY (NOT the subject field): SIGNOFF Technet >To temporarily halt or (re-start) delivery of Technet send e-mail to >[log in to unmask]: SET Technet NOMAIL or (MAIL) >To receive ONE mailing per day of all the posts: send e-mail to >[log in to unmask]: SET Technet Digest >Search the archives of previous posts at: >http://listserv.ipc.org/archives >Please visit IPC web site >http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 >ext.2815 >----------------------------------------------------- > >--------------------------------------------------- >Technet Mail List provided as a service by IPC using LISTSERV 15.0 >To unsubscribe, send a message to [log in to unmask] with following text >in >the BODY (NOT the subject field): SIGNOFF Technet >To temporarily halt or (re-start) delivery of Technet send e-mail to >[log in to unmask]: SET Technet NOMAIL or (MAIL) >To receive ONE mailing per day of all the posts: send e-mail to >[log in to unmask]: SET Technet Digest >Search the archives of previous posts at: >http://listserv.ipc.org/archives >Please visit IPC web site >http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 >ext.2815 >----------------------------------------------------- > >--------------------------------------------------- >Technet Mail List provided as a service by IPC using LISTSERV 15.0 >To unsubscribe, send a message to [log in to unmask] with following text in >the BODY (NOT the subject field): SIGNOFF Technet >To temporarily halt or (re-start) delivery of Technet send e-mail to >[log in to unmask]: SET Technet NOMAIL or (MAIL) >To receive ONE mailing per day of all the posts: send e-mail to >[log in to unmask]: SET Technet Digest >Search the archives of previous posts at: http://listserv.ipc.org/archives >Please visit IPC web site >http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional >information, or contact Keach Sasamori at [log in to unmask] or >847-615-7100 ext.2815 >----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------