DOES THE NEW REVISION OF IPC-A-600 PENDING RELEASE BY SEPTEMBER ACCEPT EXPOSE COPPER AND TO WHAT EXTEND ? AUGUSTINE 8/21 ------------------------------------------------------------------------- To : [log in to unmask],[log in to unmask] Cc : From : [log in to unmask] (R_R_HOLMES) Date : Sunday, March 5, 1995 04:31:39 HKT AT&T allows exposed Cu on PWB's, and do not consider it a reliability threat. This issue has been a topic of some discussion with Bellcore who controls specifications for domestic tele-communications equipment. They now accept the fact that exposed Cu is not a reliability threat. One of the best papers on the subject was written by two Bellcore scientists: "THE SURFACE COMPOSITION OF COPPER WITH INDOOR EXPOSURES RANGING FROM 3 TO 49 YEARS ; Rudolf Schubert and Susan M. D'Egidio; Corrosion Science, Vol 30 No 10 pp999-1008, 1990 Thia paper discusses the use of Ager spectrocopy to investigate surface films on copper bus bars that had been installed as early as 1939. They found films of 10 to 100 nanometers. These films differ chemically and in thickness from fils formed in accelerated atmosphere corrosion chambers. I hope this reference is of use. R. R. Holmes AT&T ------------- Begin Original Message ------------- Message-Version: 2 From: maxtor.com!Simon_Li Date: Tue Feb 21 22:32:15 MST 95 Received: from attme by attme.cnet.att.com; Wed, 22 Feb 1995 11:40 EST Received: from att!wwa.com!ipc!ipchq.com by ig2.att.att.com id AA25763; Wed, 22 Feb 95 11:39:25 EST Received: by gw1.att.com; Wed Feb 22 11:31:54 EST 1995 Received: from ipc by gagme.wwa.com with uucp Received: (Smail3.1.28.1 #8) id m0rhK1G-000FEhC; Wed, 22 Feb 95 10:34 CST Received: by ipchq.com (Smail3.1.28.1 #2) Received: id m0rhJRW-0000GiC; Wed, 22 Feb 95 09:57 CST End-of-Header: Email-Version: 2 Subject: copper expose Resent-Date: Tue, 21 Feb 95 22:32:15 MST Old-Return-Path: <gagme!maxtor.com!Simon_Li> Message-ID: <[log in to unmask]> To: [log in to unmask] X-Incognito-Sn: 368 X-Incognito-Format: VERSION=1.60g ENCRYPTED=NO Resent-Message-Id: <"uk8RW1.0.Au7.jxrIl"@ipc> Resent-From: [log in to unmask] X-Mailing-List: <[log in to unmask]> archive/latest/221 X-Loop: [log in to unmask] Precedence: list Resent-Sender: [log in to unmask] Original-Content-Type: text/plain; charset="us-ascii" UA-Message-ID: <[log in to unmask]> End-of-Protocol: Content-Type: text Content-Length: 138 Did anyone have any idea where I could find any article or reference about the copper expose on the PCB (GOOD OR BAD) ? thanks