Good Morning Yu-Shan, Thank you for taking the time to reply. I am not allowed to go into great detail, but generally, I am selectively etching copper versus another metal. I am using immersion due to practical constraints. I was using a commercial etchant intended for spray etch, and it was at best slow, smelly and frustrating. The smell (though I actually like the smell of ammonia) is easily dealt with in a fume hood, though it is a shared hood with production, and quite "crowded". For these reasons, I believe a two-part chemistry may be preferred for our initial work. Again, thank you for your help, it will come in quite valuable as we scale up our experiments to a more 'realistic' process. Sincerely, Jonathan Meigs AlliedSignal Oak-Mitsui (518)686-8019 -----Original Message----- From: Yu-Shan Han [mailto:[log in to unmask]] Sent: Wednesday, May 26, 1999 6:40 PM To: [log in to unmask] Subject: Re: [TN] Ammoniacal Etchant Recipe Hello again, I'm not sure about the purpose of your experiment. If the purpose is to test the adhesion of photo resist, immersion won't tell you much. If you want to study the etch rate, this works. You might be able to get the relationship curve of etch rate versus Cu++ concentration in the etchant over time. Just remember the curve shapes like a bell. The etch rate is very slow in fresh etchant. As the Cu++ builds up, the etch rate picks up. After certain point etch rate goes down due to high Cu++. That's where you want to replenish. Let me know if you need more information. Yu-Shan Han Lead One Technology, Inc. (206)368-8429 -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Meigs, Jonathan Sent: Wednesday, May 26, 1999 11:53 AM To: [log in to unmask] Subject: Re: [TN] Ammoniacal Etchant Recipe Thanks for the replies, and the reminder to be specific. I would much prefer to immerse the samples for etching (they are about 3" by 5"). If necessary, I could build a small spray etcher, I suppose, but maintaining temperature of a small volume of etchant recirculating after spray might be a challenge. Any recommendations are most welcome, and again thank you for the advice. ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################