Any conclusion on the issue of reliability of graphite deposition across the interlayer interface? Has the IPC taken/developed or is studying this for inclusion in the IPC 600 specification of acceptability? It does not appear to be an uncommon occurrence no matter whether the multilayer is made from epoxy or PTFE to see random interconnects where the graphite colloid is completely across the interface, and under normal examination magnifications it looks like resin smear. Anybody accepting this defect or calling it not a defect???? Any inputs would be appreciated, THANKS Ted.A.Edwards @CAS.honeywell.com ---------- From: [log in to unmask] To: [log in to unmask] Subject: RE: Gelatinous residue on High Tg Material Date: Friday, June 28, 1996 1:04PM This gelatinous residue, that you discribe, appears to be the same substance we have encountered from the new direct plating process which utilize graphite. We have performed evaluations of the effects on performance and long term reliability issues but have not yet made any conculsions. My suggestion is that you ask your supplier if they are using one of the new direct metalization processes being introduced into the market place, instead of the old electroylsis process. ---------- From: [log in to unmask] To: [log in to unmask] Subject: Gelatinous residue on High Tg Material Date: Thursday, June 27, 1996 7:34PM Has anyone noticed a thin layer of gelatinous residue between the copper plating and the laminate during X-section inspection? What we are seeing appears to be isolated occurances of hole wall separation when viewed at 100-200X. Closer examination at 500-1000X reveals a thin layer of gelatinous residue (approx. 100-200 Microinches thick) on the back side of the plating. So far I have only observed the problem on the B-stage material which happens to be a high Tg (170 degree) FR4 material. We are using KMnO4 desmear. The residue differs from normal holewal pull away as follows: 1. There are small inclusions that are coated with electroless copper and have a dark center extending .0001-.0003 inches into the electroplated copper. Similar to a glass fiber inclusion. 2. The contour of the laminate face and the contour of the electroplated copper do not match in the area exhibiting hole wall pull away. There is a layer of gelatinous residue on the backside of the plating that produces different contours and separates from the laminate. 3. The gelatinous material has an irridesent appearance. 4. When polarized light is used the gelatinous materila looks like the base laminate. If the material were polishing debris the material would be white and have a crystalline appearance. I know of at least one other company who have seen similar problems with a high Tg FR4. Are there others? If any one else observes a similar problem please let me know. Thanks Wendell Conner *************************************************************************** * 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. * ***************************************************************************