Bill, My experience with the type ovens you describe have shown them to do an excellent job of exhausting outgassed material and precluding redeposit on a board or substrate surface. If it is outgassing, I would tend to believe that you would see a difference in wire bond pull strengths as well. Especially when comparing before/after accelerated bakes. Is this the case? Please forgive me, but are you absolutely sure the same lot and even same syringe/application of epoxy was used on both board types? Bruce Misner > ---------- > From: Bill Christoffel[SMTP:[log in to unmask]] > Reply To: TechNet E-Mail Forum. > Sent: Thursday, September 06, 2001 9:03 AM > To: [log in to unmask] > Subject: [TN] Outgassing of LPI's and Legend Inks > > Technetters, > > We are experiencing what appears to be the result of some type of > outgassing of white legend ink. > Details: Board design uses a white legend ink as an overcoat. > Subsequent processing includes die attach (COB) using electrically > conductive epoxy. Testing shows that the die attach epoxy strength (die > shear) is greatly reduced on boards that use the white legend ink. I do > not believe this to be a surface contaminant issue since the epoxy > failure mode is cohesive. Epoxy cure temperature is 150C in a air > circulating oven with a high exhaust rate. Questions - Is outgassing > of legend inks and LPI's a probable cause? Is any information > available regarding this ? > > Bill C. > > -------------------------------------------------------------------------- > ------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8d > 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 delivery of Technet send the following message: SET > Technet NOMAIL > Search previous postings at: www.ipc.org > On-Line Resources & Databases > > E-mail Archives > Please visit IPC web site (http://www.ipc.org/html/forum.htm) for > additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > -------------------------------------------------------------------------- > ------- > --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------