An ionic test can be misleading as you can have zero ionics and still have 100% surface contamination with non-ionic. If you want to know what is there then you will need to do a lab based investigation as suggested. On a pragmatic basis you can do a wire bond and then do a pull test. Alternatively even more pragmatically you might just try some over volts through the wire. Any trapped organics will vaporise and blow the wire off or the wire will melt. There is reasonable correlation between surface junk and pull results, at least to start. The over volts is a crude yes no but have seen known percent over volts used as an inline test on power devices. Mike Fenner Indium Corporation of Europe T: + 44 1908 580 400 F: + 44 1908 580 411 M: + 44 7810 526 317 W: www.indium.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Andrew Hoggan Sent: Tuesday, August 07, 2001 6:04 PM To: [log in to unmask] Subject: Re: [TN] Contamination Concern after Strip Well Bill, I'll happily stand correction, but I think it's difficult to confirm gold cleanliness. With copper you can try a spot of etch or flux on the copper area, if there's mask residue then the chemical won't touch the copper, normally you'll notice the difference between oxidised copper and the fresh etched. With gold you couldn't get away with that. If you can get your board into a SEM-EDX chamber you could look for organic residue on the gold surface. Best regards, Andrew Hoggan BBA Associates Ltd www.bba-associates.com -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Bill Christoffel Sent: 07 August 2001 14:04 To: [log in to unmask] Subject: [TN] Contamination Concern after Strip Input Needed ! We currently use a board that is designed for gold ball bonding (COB) and have specified electroplated gold as the top metal layer. This board also uses a Tayio solder mask material that is flood coated over the top, including the gold pads then photo imaged/etched. to expose specific gold pads for wire bonding. My concern is that the solder mask may be leaving some type of contamination on the bonding pads. If so, I'm looking for recommendations on how to verify cleanliness, other than ionically (which we do) and how to remove any contamination. Thanks, Bill C. --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------