Steve, You bring up a topic I spent many years of my life working on. I was the former product manager for Dynachem/Morton/Shipley in charge of solder mask products (I am no longer employed by them). I was part of the development team that developed and commercialized the Dynamask Dry Film Solder Mask Products. You didn't mention which version of Dynamask you had or how thick the product is. There are two versions of the product; Dynamask KM and Dynamask 5000. Dynamask KM is available in two thickness; 3 mil and 4 mil. Dynamask 5000 is available in (I believe this is still true) 2 mil, 3 mil and 4 mil. Let me give you a little background on why you are seeing less chemical resistance. When the original version of this product was designed there were no true class III (under IPC SM 840 B) dry film solder masks. The main problem was related to thermal cycling. The current dry film product offerings (this was back in the late 80's) could not make it to 100 cycles required under SM 840 B. If you were to examine the products that were on the market after thermal stress (multiple soldering operations; surface mount and through hole) you would find micro cracking. This cracking became worse with each thermal excursion. This was a problem for both board manufactures and end users as technically, the available dry film products at the time could not be used in high reliability environments. At the time dry film solder masks were the predominant photoimageable solder masks as liquid photoimageable masks were just gaining market acceptance and were still expensive. Decisions had to be made in which path we were going to pursue in order to gain class III approval with the next generation dry film product (Dynamask KM). It was decided to go with a more flexible material that would be more compatible with the laminate expansion during thermal stress. The trade off was less chemical resistance. Several studies were conducted to determine if this would be a major issue in the environment the product was expected to perform in. We found common cleaners available on the market would be compatible with the product AS LONG AS YOU FOLLOWED CONCENTRATION, TEMPERATURE AND DWELL TIMES recommended by the various manufactures. With N0-Clean fluxes becoming the standard at the time this appeared to be a reasonable trade off. Yes the product from Dupont was more robust in some processes. The Dynamask product outperformed the Dupont product in some processes as well. The problem was when there was failure with Dynamask, it usually was something like you described. The other competitive product's failures were often more subtle. Dynamask 5000 was developed to give more chemical resistance while maintaining the class III capabilities. The product did show measurable improvements in cleaning systems that used to give us problems. However, the product could still fail if pushed to it's limits of chemical resistance. Now to your current problem. The Zyzen product was one that I used to get a lot of phone calls about. Usually we could correct the problem by checking the concentration, temp and dwell time. And yes, most of the time we had failures it was in a batch system. Temperature is more inconsistent is many batch cleaning systems that are out there. You can re-mask as someone else suggested. My experience is most current available liquid photoimageable soldermasks are compatible with Dynamask. I have used Shipley liquid photoimageable soldermask many times but have found Taiyo and Enthone to work well also. Keep in mind there are many different versions of "Taiyo" and "Enthone" and you will need to run your own compatibility testing. Also check with your board supplier to insure they are properly curing Dynamask. Both KM and 5000 need a significant UV cure in addition to a final thermal bake. UV energy in the range of 3000-5000mj cm is required. Thermal curing is 300 F for 60 min. Have your vendor check their UV curing unit out. Bulbs with more that 1000 hours use put our more IR than UV but will still look OK on many radiometers. Old bulbs have caused many failures over the years. Also the reflectors need to be cleaned when the bulbs are changed. Also have them check out their thermal curing ovens. Most use batch ovens that can have major temperature fluctuations. A thermal profile should tell them if the boards are seeing proper cure temp in all parts of the oven. Sorry for the long response but I felt a little background info my help. Regards, Bob Metcalf 949-709-2544 -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Stephen Gregory Sent: Tuesday, May 17, 2005 9:28 AM To: [log in to unmask] Subject: [TN] Bubbly, flaking, soldermask... Hi All... Boy, I hope your day is going better than mine... One of my inspectors called me to to look at an assembly she had. I came to her station and started looking at the assembly, and just about cried (not really). I observed something that I've seen before... The solder mask is losing adhesion from all copper features, traces, vias, everything copper. This starts occuring after about 2-3 wash cycles in our batch cleaner. Take a look at; "Mask Bubble, Mask Bubble 2, 3, and 4", at: http://www.stevezeva.homestead.com I've seen this before and thought we had the problem taken care of. It's caused by the chemistry we use to clean RMA flux residues, not being compatible with certain dryfilm solder masks. We use Kyzen Aquanox 4512P in the manufacturers recommended concentration, and we see this problem everytime a Dynachem Dynamask (now Shipley) dry film is used. We used to use Aquanox XJN and had the same problem. On our PO's we have a note that when dry film solder mask is called out on the fab drawing, use Dupont Vacrel series dry films, as we know that we have absolutely no problem with Vacrel. The last time I had this problem and posted about it, there were a few responses that I shouldn't be having these problems, that the Dynachem Dynamask dry films are very robust. But I swear, everytime I see the mask bubbling and flaking like you see in the images I've posted, it turns out that a Dynachem dry film was used. Can I be the only one that has these probelms? Kind regards, -Steve Gregory- Senior Process Engineer LaBarge Incorporated Tulsa, Oklahoma (918) 459-2285 (918) 459-2350 FAX __________________________________________________________________ This message may contain information that is privileged and confidential to LaBarge, Inc. It is for use only by the individual or entity named above. If you are not the intended recipient, you may not copy, use or deliver this message to anyone. 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