I have also seen the problem with decreased solder mask adhesion to the board. Our board vendor had to switch solder masks and print two passes of it to effectively cover the board (I have no idea why two passes were required). The results were good except for the matte finish of the new mask, which we are afraid will ultimately pick up more contaminants than the very shiny finish of the original mask. Does anyone have any specific recommendations for a solder mask that is compatible with white tin processing and has a smooth surface finish? Our actual goal is lowest SIR and highest reliability over the long term (10+ years). The environment is a medical laboratory so it is very benign and we specify class 2 performance. This is an FR-4 board, 4-layer, 0.062" thick, 1 oz. copper per layer, SMOBC: no rocket science here. Regards, Seth Goodman Goodman Associates, LLC tel 608.833.9933 fax 608.833.9966 -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Neil Atkinson Sent: Tuesday, August 21, 2001 3:08 AM To: [log in to unmask] Subject: Re: [TN] White Tin I agree. The question was 'as an alternative to HASL". As an alternative to HASL immersion tin can be very good with all the benefits mentioned earlier. One problem to watch out for is compatibility with solder resist - it can attack some resists causing problems - use a robust resist and you should see few problems. Like the man said - try it and see what you think. It's the old horses for courses - immersion gold might be the right finish for your application but I would definitely try immersion tin first. Neil Neil Atkinson --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------