Hi Howard - Steve and Inge have provided you some good stuff so I can only offer one additional detail. The reason for the 5000 ppm limit is that is the' line in the sand' where you will get condensation inside a hermetically sealed package as you go thru temperature swings. There are a bunch of very fun mathematic equations which can be used to show that below 5000 ppm you won't get condensation as you go thru the dew point. With a reading of 5600, you may want to evaluate "are you good enough" in terms of would water cause you issues in your product use environment. Good Luck. Dave Hillman Rockwell Collins [log in to unmask] From: "Watson, Howard A" <[log in to unmask]> To: <[log in to unmask]> Date: 12/13/2012 05:25 PM Subject: [TN] Component issue - epoxy die attach Sent by: TechNet <[log in to unmask]> Hello 'netters, I debated posting this, as it seems to me to be an obscure problem, but then, I'm always amazed at your knowledge base. I have a JFET 2N6550 component to be used for space application. Unfortunately, it is not manufactured at JANS space quality, so we buy the commercial grade, plus an option 2 screening, which upscreens the part to "like" JANTXV. I think this is called re-branding. Then, we send it to a lab for further upscreening to JANS. The problem is that the parts are failing the moisture test of the residual gas analysis (RGA). I found out that epoxy is used for the die attach, and likely the epoxy is outgasing during subsequent baking as part of the testing. My first question is who knows of a standard for die attach of this component type stating that epoxy is forbidden for military and space use? The epoxy used by the manufacturer is Ablestik p/n 84-1LMI; Material # 1119570. I just found out today that they do have the capability of eutectic die attach, and I'm pursing this option, expecting a huge expense and lead time. Secondly, I had two independent labs perform the RGA. The first lab had results averaging ~28,000 PPM. The second lab results averaged ~5600 PPM. The standard is no more than 5000 PPM. They both performed the testing to the same MIL-STD-750. I can't understand the wide range of results, but my second question is who knows of any studies related to the negative effects of excessive (>5000 PPM) moisture inside hermetically sealed devices used in space? By the way, they all passed the seal tests. Perhaps some of you are knowledgeable in this area. Thanks in advance for your help. Howard Watson ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________