Good Afternoon, I am appending the following for a fellow engineer in my dept. that does not have the capability to append directly. I will forward any and all responses to Mr. Ayotte - Thx. In Advance...Jay Edwards ------------- With respect to the attached ATT response; what I am wondering is: - what are the voltage applications for the products that ATT uses single sheet prepregs in? - is this true for signal/signal, signal/power and power/power applications? - what are the reliability requirements for the products this is being used in (0.1 ppm/KPOH or 10 ppm/KPOH or higher)? - is this consumer products, games and toys or mainframe? - what prepreg thickness/thinness does ATT use? Any and all information is greatly appreciated. Thanks in advance Stephen Ayotte, IBM MD Quality Engineer ************************************************************************ Received: from gagme.wwa.com by vnet.IBM.COM (IBM VM SMTP V2R3) with TCP; Wed, 24 May 95 13:11:24 EDT Received: from ipc by gagme.wwa.com with uucp º(Smail3.1.28.1 #8) id m0sEJSm-000FHYC; Wed, 24 May 95 11:39 CDT Received: by ipchq.com (Smail3.1.28.1 #2) ºid m0sEItM-0000GmC; Wed, 24 May 95 11:02 CDT Old-Return-Path: <miso!attme.att.com!rgrrh> Message-Id: <[log in to unmask]> Date: 24 May 95 10:18:06 -0400 To: [log in to unmask], [log in to unmask] From: [log in to unmask] (R_R_HOLMES) Original-Date: Wed May 24 10:18:06 EDT 1995 Phone: (804) 226-5114 Subject: Re: single ply dielectric and "green" laminate Original-To: compuserve.com!100430.2627 Original-To: [log in to unmask] In-Reply-To: your message of May 22 18:28:11 EDT 95 Content-Type: Text Resent-Message-ID: <"6GyxY3.0.wvD.VYrml"@ipc> Resent-From: [log in to unmask] X-Mailing-List: <[log in to unmask]> archive/latest/535 X-Loop: [log in to unmask] Precedence: list Resent-Sender: [log in to unmask] AT&T has been using single ply B-stage for several years and is in the process of converting all product to single sheet. We have seen no reliability problems, and believe that a single ply is as reliable as two plies. We are in the process of converting all products to single sheet (5 mil, 6 mil, 8 mil 10 mil). We also make PCMCIA cards with 2.8 mil single sheet glass. The only real risk with single sheet glass is the possibility that a dielectric void could bridge layer to layer through the glass cloth. With modern PWB processes this is a limited risk. In addition, in some cases, a tight weave single sheet glass provides a tighter barrier than two sheets of an open weave. The only field problem that I remember actually occured with two sheets of an open weave (1080 glass). In conclusion, AT&T believes that single sheet constructions are very reliable and we are using them in most of our products. º------------- Begin Original Message ------------- Message-Version: 2 From: compuserve.com!100430.2627 Date: May 22 18:28:11 EDT 95 Received: from attme by attme.cnet.att.com; Tue, 23 May 1995 12:03 EDT Received: from att!wwa.com!ipc!ipchq.com by ig2.att.att.com id AA23053; Tue, 23 May 95 11:07:54 EDT Received: by gw2.att.com; Tue May 23 11:08:31 EST 1995 Received: from ipc by gagme.wwa.com with uucp Received: (Smail3.1.28.1 #8) id m0sDvZG-000FHuC; Tue, 23 May 95 10:08 CDT Received: by ipchq.com (Smail3.1.28.1 #2) Received: id m0sDuxN-0000GqC; Tue, 23 May 95 09:29 CDT End-of-Header: Email-Version: 2 Subject: single ply dielectric and "green" laminate Resent-Date: 22 May 95 18:28:11 EDT Old-Return-Path: <miso!compuserve.com!100430.2627> To: [log in to unmask] Message-ID: <[log in to unmask]> Resent-Message-Id: <"uIUpG3.0.d59.p4Vml"@ipc> Resent-From: [log in to unmask] X-Mailing-List: <[log in to unmask]> archive/latest/533 X-Loop: [log in to unmask] Precedence: list Resent-Sender: [log in to unmask] End-of-Protocol: Content-Type: text Content-Length: 545 To what extent has the PCB industry changed to single ply for pre-preg as opposed to core which has been available in single ply for a long time. What are the fears about single ply pre-preg? Are 2 plies really better than 1 thickone? What are the attitudes towards so called "green laminate"? Is it simply a case of eliminating bromine, is it vital to meet UL V- 0 if the alternative could have such an impact on the environment? These questions were prompted by a major user of PCBs in Europe. George Wheadon Nelco UK .. º /NO SUBJECT F