That is not resin recession. That is "true" etchback if also using a glass etch. Resin recession is resin that was once attached to the hole wall and pulled away during a thermal cycle. As pointed out earlier, it is sometimes mistakenly called hole wall pullaway which is an entirely different defect. At one time I thought it was caused by the sectioning technique or exotherm potting compounds, but was never able to verify. gary mccauley -----Original Message----- From: Rick Howieson [mailto:[log in to unmask]] Sent: Wednesday, December 05, 2001 9:55 AM To: [log in to unmask] Subject: Re: [TN] RESIN RECESSION Earl, Are you asking what causes resin recession? If so, it scares me the fellow from BOEING couldn't figure it out. It occurrs in the board fab process during the removal of resin smear after drill. There are two ways I'm familiar with. One using permanganate (chemical), two using plasma. If left in too long the resin is removed back into laminate potentially causing dielectric spacing problems. Rick -- --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------