First off, regarding any reaction that generates or used chlorine gas it requires a thorough understanding of the operation and chemistry of the system. Only personnel with proper equipment and that definitely includes very good ventilation with a fume scrubber on the ventilation system, and more importantly a good understanding should attempt to do this as the reaction basically involves the addition to the solution of chlorine gas or creation of chlorine gas in the solution and you do not want this nasty chemical in your breathing area Chlorine gas really can kill you, and if it does not get you when you breath it can cause chemical pneumonia. A good chlorine detection and alarm system should also be installed. I would suggest you talk to your etcher machine supplier, or if you are just contemplating this talk to Marshal Gurian at ASI 602-276-7361 (who makes etching systems)as they have a lot of experience. Over the years there have been a number of units to add the HCl and sodium chlorate starting with Vis-U-Etch or the Chemcut colormetric solution color monitoring system. ORP overcomes a problem that all the colormetric systems had at one time or another of salts plugging the line to the colormetric cell but even with it some maintenance is required as the chemistry is corrosive, it does not know which copper you want to keep (the system wiring) and that which you want to remove ( the excess copper on the board). I have used both chlorine gas and chlorate/HCL and for ease of operation the chlorate is IMO easier to operate. Opening the chlorine gas cylinders requires a vacuum which means you need an injector large enough to generate a good vacuum. Here are some literature references you might want to look at. Steady State Etching of Copper-Cupric Chloride, Sodium Chloride Baths, L.Missel and F.D.Murphy, Metal Finishing, December 1969 p47-52,58. Steady State Regenerative Etching: A Technology Review, Marshal Gurian, ASI, Electronic Packaging and Production July 1978, p32-36. Etchant Fountain of Youth? Circuits Manufacturing, November 1976, p 72-73. I also think I heard that chlorine gas cylinders must now be in a enclosure that completely contains and neutralizes all gas if their is any accidental releases and you may want to ask about whether this is a requirement. [log in to unmask] The opinions expressed here are those of Ted Edwards and may or may not reflect the opinion of my employer. ---------- From: Ted Stern To: [log in to unmask] Subject: FAB: Cupric chloride regeneration with sodium chlorate Date: Wednesday, January 22, 1997 1:07PM I was wondering if any of you fabricators out there would provide me with information on the following: a. method of regerating CuCl2 final etch with sodium chlorate, including sodium chlorate concentration, HCl additions, rate of additions, equipment used; b. method of automated control (ie. ORP control versus colormetric control); and c. opinions on the ease of use (or lack thereof) of sodium chlorate versus chlorine gas; Thanks for you help! Ted Stern 612-479-6525 [log in to unmask] *************************************************************************** * 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. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * 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. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************