======== Original Message ======== Sender: [log in to unmask] Received: from simon.ipc.org (IPC.ORG [168.113.24.64]) by arl-img-7.compuserve.com (8.6.10/5.950515) id XAA24848; Wed, 10 Jul 1996 23:11:52 -0400 Received: from ipc.org by simon.ipc.org via SMTP (940816.SGI.8.6.9/940406.SGI) id WAA05952; Wed, 10 Jul 1996 22:09:36 -0700 Resent-Date: Wed, 10 Jul 1996 22:09:36 -0700 Received: by ipc.org (Smail3.1.28.1 #2) id m0ueBc2-0000DKC; Wed, 10 Jul 96 21:36 CDT Resent-Sender: [log in to unmask] Old-Return-Path: <[log in to unmask]> Date: 10 Jul 96 22:42:08 EDT From: "Hans M. Rohr" <[log in to unmask]> To: "INTERNET:[log in to unmask]" <[log in to unmask]> Subject: Re: Ammoniacal Etching Speed Message-ID: <[log in to unmask]> Resent-Message-ID: <"B2yPI.0.MAG.VY6vn"@ipc> Resent-From: [log in to unmask] X-Mailing-List: <[log in to unmask]> archive/latest/5074 X-Loop: [log in to unmask] Precedence: list Resent-Sender: [log in to unmask] Does anyone have information or data on what chemical control limits are required (specific gravity, pH, temperature, etc.) to maintain a constant etcher conveyer speed for a given copper plating thickness such as 1 oz base and 1 mil electroplated Cu? We have done a lot of testing and tried a lot of control schemes. Nothing seems to work reliably. We still etch one piece, measure the line width, adjust the conveyor speed accordingly and then run the lot. Hans Rohr. *************************************************************************** * 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. * *************************************************************************** ======== Fwd by: Tony King / N ======== Hans, It may not be the chemical concentrations so much, but the controller used to maintain the chemistry. Not all controllers are created, the low end units use a float/sink mechanism, while the better units measure the baume and use high-tech electronics for automated chemical addition. The high end units maintain a much tighter range which makes etching more uniform before and after additions. MacDermid offers a very good higher end controller which I have used very successfully for years called the MACTROL. Another approach to consider is the first piece system you presently have. Based on your average lot size and first piece inspection turn time, match up the copper weights and process the first piece for the next lot part way through the preceding lot so that when your first lot is done your second lot is ready to process, and so on. This would minimize the amount of dead time by keeping the etcher filled with product. The more an etcher is worked the better it performs. This system will not prevent the need to adjust conveyor speed, but does minimize problems. The etcher is a dynamic system with many interdependent elements which will reach equalibrium if properly maintained and worked. The standard parameters I use are 23.5 baume, 8.0 to 8.5 pH and a temperature of 125 F. The single most important control in maintaining the etcher, proper ventilation due to the impact on pH and chloride concentration !! Call me if you would like to talk. Tony King Elexsys International 603-886-0066 *************************************************************************** * 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. * ***************************************************************************