Pete I must have skipped over the original message. I thought it was looking for a book. Repeat what you want to bond to and I bounce back some ideas. Carey -----Original Message----- From: Pete Nemcik <[log in to unmask]> To: [log in to unmask] <[log in to unmask]> Date: Tuesday, March 07, 2000 5:49 AM Subject: Re: [TN] Surface prep before soldermask Many thanks, Brian, and apologies to everybody. I meant to send the original to Brian only. I always realize my screw-up right AFTER I hit the send button!!! Pete > -----Original Message----- > From: Brian Ellis [SMTP:[log in to unmask]] > Sent: Tuesday, March 07, 2000 4:38 AM > To: [log in to unmask] > Subject: Re: [TN] Surface prep before soldermask > > Pete > > Lest I be accused of spamming, I'll send you the title by a private > e-mail. Although I > have no experience of the problem, I could well imagine that it may be > difficult to > weld a gold or aluminium wire onto an implanted carborundum particle > from a brushing > process :-) However, as the particles are much smaller than the weld > diameter, it may > be that you would not notice the reduction of pull strength. However, > as the > carborundum is less malleable than the gold plating, it may be that > there would be a > mechanical effect whereby the pressure on the metal-to-metal parts > would be reduced > while that of the metal-to-inclusion would increase, but this is off > the top of my > head. I don't think that the substrate material would have a > significant effect. > > Brian > > Pete Nemcik wrote: > > > Hi Brian > > Can you share with me the title of your book? I am very interested. > > Also, would this abrasive implanted contamination affect wire > bonding? I > > would imagine that the effect of these particles imbedded into the > gold > > would interfere with proper bonding of the wire (especially if the > > substrate is Teflon filled with ceramic filler). > > Thanks in advance > > Pete > > > -----Original Message----- > > > From: Brian Ellis [SMTP:[log in to unmask]] > > > Sent: Tuesday, February 29, 2000 5:54 AM > > > To: [log in to unmask] > > > Subject: Re: [TN] Surface prep before soldermask > > > > > > Adeodato > > > > > > It is about a hundred years since I did this, so what I say is > > > certainly > > > out of date! Our preferred method was to clean the board with a > good > > > hot > > > (55°C) agitated DI water wash with 10% IPA, followed by a single > DI > > > rinse at 85°C, followed by a 30°C dilute sodium persulfate (not > > > ammonium) etch to remove c. 2 um of copper followed by 3 DI > rinses. > > > Oxide-free drying was done by successive pure IPA (to remove the > gross > > > water) and toluene displacement, followed by placing in a walk-in > oven > > > with filtered air at 30°C for 5 hours minimum.. This produced a > > > residual > > > ionic contamination of < 0,3 ug/cm2 eq. NaCl, where the then > > > MIL-P-55110 > > > suggested a max of about 1,3-1,5 ug/cm2 eq. NaCl depending on your > > > interpretation. Solderability was excellent. We did this with both > dry > > > film and liquid screened masks. Do NOT use abrasives or brushing > of > > > any > > > sort: you smear epoxy onto the copper and implant abrasives into > the > > > copper, causing a certain dewetting (see my book for full > details). > > > > > > Brian > > > > > > > > > Adeodato Vigano wrote: > > > > > > > TechNet,I would like to hear the Forum's opinions about > > > pre-cleaning > > > > before soldermask (both Dry Film and LPI), in particular about > the > > > > methods based on chemical rather than mechanical action.We are > > > > evaluating an "oxide replacement" chemistry versus different > > > microetch > > > > chem-clean systems. The microetch would be our preference > because > > > > running thick panels through our oxide replacement equipment may > > > > result in damage to the line, of course we are getting good > results > > > > from the oxide replacement chemistry but we are not getting > > > consistent > > > > results from the chem-cleaning process.Also I would like to know > > > what > > > > other PCB manufacturers are doing when they are not using > mechanical > > > > scrubbing methods.Any suggestions regarding chemistry and/or > process > > > > parameters would be greatly appreciated.Thanks in > advanceadeodato > > > > viganocompunetics, inc. - pcb divisionphone: 412.858.6115fax: > > > > 412.858.8060email: [log in to unmask] > > > > > > ############################################################## > > > TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for > > > additional > > > information. > > > If you need assistance - contact Keach Sasamori at [log in to unmask] > or > > > 847-509-9700 ext.5315 > > > ############################################################## > > > > ############################################################## > > TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for > additional > > information. > > If you need assistance - contact Keach Sasamori at [log in to unmask] or > > 847-509-9700 ext.5315 > > ############################################################## > > ############################################################## > TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for > additional > information. > If you need assistance - contact Keach Sasamori at [log in to unmask] or > 847-509-9700 ext.5315 > ############################################################## ############################################################## TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ############################################################## ############################################################## TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################