There may be a medical explanation, he may have relation genetically with Caesar Claudius...he stammered Inge On 14 December 2012 19:39, Graham Collins <[log in to unmask]> wrote: > Wait a minute here! If Doug is Emperor, why does he say "it depends" so > much??? For royalty all pronouncements are supposed to be absolute truths! > > Imposter, I say. > > regards, > > Graham Collins > Senior Process Engineer > Sunsel Systems > (902) 444-7867 ext 211 > > > On 12/14/2012 12:33 PM, Steven Creswick wrote: > >> Is "Mountain Dew" related to moonshine in its effects upon the human body? >> >> -----Original Message----- >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D. >> Sent: Friday, December 14, 2012 11:28 AM >> To: [log in to unmask] >> Subject: Re: [TN] Component issue - epoxy die attach >> >> Well, maybe not a Coke, but I have seen the masses arriving at the Technet >> expos and forums toting cases of Mountain Dew in order to pay appropriate >> tribute to Emperor Pauls. >> >> -----Original Message----- >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls >> Sent: Friday, December 14, 2012 10:09 AM >> To: [log in to unmask] >> Subject: Re: [TN] Component issue - epoxy die attach >> >> Well, I have been Emporer now for 8 years and have yet to get a burger and >> coke out of it. >> >> Doug Pauls >> >> >> >> From: Steven Creswick <[log in to unmask]> >> To: <[log in to unmask]> >> Date: 12/14/2012 10:07 AM >> Subject: Re: [TN] Component issue - epoxy die attach >> Sent by: TechNet <[log in to unmask]> >> >> >> >> Emperor Doug, >> >> >> Wow! TechNet is so wonderful! >> >> >> Not only can you get all kinds of information and opinions on just about >> everything under the sun, but you can get titles too!! >> >> >> How much more do I need to get a burger & coke? >> >> >> Steve C >> >> >> From: [log in to unmask] [mailto:dopauls@**rockwellcollins.com<[log in to unmask]> >> ] >> Sent: Friday, December 14, 2012 9:12 AM >> To: TechNet E-Mail Forum; Steven Creswick >> Subject: Re: [TN] Component issue - epoxy die attach >> >> >> Steve, >> Hell, take the Title and have some fun with it. >> >> At IPC, I decided that General Chairman, Cleaning and Coating Committees >> was >> too boring a title. So I bestowed the Title of Emporer on myself. >> Debbie Obitz became Vice Empress. >> Graham Naisbitt is the head of the Jedi Council John Perry and Kris >> Roberson >> are now Grand Moffs. >> We have a few System Lords running around. >> >> We definitely have more fun than the other General Committees. >> >> So have fun. Maybe Inge can be the Marquis of Micro. Mr. Stadem can be >> Duke of DRAMS........ >> >> Doug Pauls >> >> >> >> From: Steven Creswick <[log in to unmask]> >> To: <[log in to unmask]> >> Date: 12/14/2012 04:53 AM >> Subject: Re: [TN] Component issue - epoxy die attach >> Sent by: TechNet <[log in to unmask]> >> >> _____ >> >> >> >> >> Inge, >> >> >> >> Not so sure I desire / deserve that title. >> >> >> >> I would submit it to you instead. >> >> >> >> >> >> Howard, you have asked a few questions for which there likely are no >> perfect >> answers except, "it all depends". >> >> >> >> "Back in the day", I was familiar with some commercial 'hermetic' parts >> that >> I would not recommend anyone use. >> >> >> >> I agree with Inge that processes have improved [and most of the really bad >> suppliers no longer exist], but I view RGA results as a planned goal >> related >> to adhesive processing, overall component cleanliness, and pre-seal >> processing conditions. The RGA results are only as good as your process >> leading up to the sealing operation. Once the package is sealed, it is a >> done deal. You cannot screen out for RGA on a piece by piece basis, as >> you >> can with electrical test. Die attach, wire pull and electrical test >> results >> should be almost transparent across the spectrum from COM, MIL, to Space. >> The only difference is that one normally imposses greater requirements, >> and >> increased testing frequency on MIL/Space than on the COM product. And for >> reference, with the exception of radiation hardness, Implantable Medical >> devices were as tight, or tighter than Mil/Space >> >> >> >> Now then, many manufacturers that make both Commercial and Mil product >> will >> often share a great deal of processes, but sometimes Production, is >> Production.. If a Mil pre-seal bake was 24-36 hrs, a corresponding Com >> bake >> may have only been 8-12 hrs. Pre-seal bake and vacuum bake ovens attached >> to the sealing chambers are limited in size, so one would not generally >> allow a Com grade part to unnecessarily take up resources. Maybe 8-12 hrs >> is not quite good enough to meet Mil specs. that's why it is processed as >> a >> Com part. >> >> >> >> Sorry we are not giving you a clean answer to your questions. >> >> >> >> Inge's wealth of documents will be helpful in your education, however. >> >> >> >> >> >> >> >> Still time for me to bundle up and check out the meteor shower!!! >> >> >> >> Best wishes, >> >> >> >> Steve Creswick >> >> >> >> From: Inge Hernefjord [ <mailto:[log in to unmask]**> >> mailto:[log in to unmask]] >> Sent: Friday, December 14, 2012 3:08 AM >> To: TechNet E-Mail Forum; Steven Creswick >> Subject: Re: [TN] Component issue - epoxy die attach >> >> >> >> Howard, >> >> I'm afraid we do bombard you with facts so will be choked. Therefore, I'll >> take it slowly. >> >> 1. Steve is King of Micro, listen to him >> 2. Nothing wrong with upgrading commercial to MIL or SPACE. JAN, QL, >> etc >> too expensive, will disappear. Semi processing been so good today, that >> there is nearly no difference between commercial and MIL production. >> 3. I send offline to you an article, that is a good one to start with. No >> meaning to complicate the question. Suitable drink for this paper: 4 cl >> Isle of Jura >> 4. Epoxy hysteria was initially because its outgassing caused trouble for >> all optics in SPACE parts. Agree with the King, well processed epoxies do >> no >> harm. >> >> >> >> Inge >> >> On 14 December 2012 03:14, Steven Creswick <[log in to unmask]> >> wrote: >> >> Joyce - Agree, but so do the Ni & Au platings. >> >> If the package had a hole so large that the helium was absorbed enmass in >> the adhesive, it should have failed hermeticity due to the presence of He >> - >> or gross leak testing. >> >> I hope that he can at least trust that the hermeticity test was done >> properly. You are right though, if that is not done correctly, all is >> lost. >> >> Without being privy to the manufactures methods, it appears as though one >> is >> attempting to make a silk purse from sow's ear. >> >> It is my opinion that meeting RGA requirements is not a 'will test later' >> kind of requirement - unless you plan to do 100% [destructive] testing. >> Meeting RGA requirements is something that one needs to plan for, and >> process accordingly, from the beginning. >> >> >> >> Steve Creswick >> Sr Associate - Balanced Enterprise Solutions >> <http://www.linkedin.com/in/**stevencreswick<http://www.linkedin.com/in/stevencreswick> >> > >> http://www.linkedin.com/in/**stevencreswick<http://www.linkedin.com/in/stevencreswick> >> >> >> >> >> >> -----Original Message----- >> >> From: Joyce Koo [ <mailto:[log in to unmask]> mailto:[log in to unmask]] >> Sent: Thursday, December 13, 2012 9:02 PM >> To: [log in to unmask]; [log in to unmask] >> Subject: Re: [TN] Component issue - epoxy die attach >> >> Steven, epoxy absorb He. If he did He leak test, pass hermidicity means >> nothing. My 2 cents. >> -------------------------- >> Sent using BlackBerry >> >> >> ----- Original Message ----- >> From: Steven Creswick [ <mailto:[log in to unmask]**COM<[log in to unmask]> >> > >> mailto:[log in to unmask]**COM <[log in to unmask]>] >> Sent: Thursday, December 13, 2012 08:58 PM >> To: [log in to unmask] <[log in to unmask]> >> Subject: Re: [TN] Component issue - epoxy die attach >> >> Howard, >> >> Sorry, this will be a bit long. >> >> I am glad you stated that the packages passed hermeticity testing. That >> would have been the first item to check. >> >> I assume this is TO-5 or smaller style package. The smaller volume >> packages >> can be problematic if there is a leak during puncture of the package >> because >> the available tested volume is so small compared to a potential leak. >> >> Different labs used to test for RGA in different manners, with different >> style equipment. >> >> On one style of test equipment, the sample package would be placed into >> the >> evacuated test chamber and punctured/broken. The sample gas would then >> flow >> into the chamber and subsequently be taken into the mass spec. >> >> Other equipment relied upon placing the package up against the sampling >> port, sealing it via an o-ring [of sorts]. Once fixed against the >> evacuated >> sampling port, a needle would protrude through the center of the o-ring >> and >> puncture the package lid, allowing the test gas to enter the mass spec. >> >> Both methods have pro and cons. The chamber method is most convenient for >> all-ceramic style packages where there is no metal lid to puncture. A >> problem with it is that the entire exterior of the package must be >> thoroughly cleaned, but can still carry ad/absorbed species into the test >> chamber. Plated surfaces also can contain a great deal of trapped >> hydrogen >> put down during plating. Some systems would see Hydrogen, and log it as >> H2O. >> >> With the puncture method, if the lid is too robust, the act of puncturing >> could displace the sample from the seal and allow atmosphere to be >> introduced, thereby squirreling up the data. Most hybrids had >> 0.010-0.020" >> thick lids and what WE often did was to take a small end mill [~0.050" >> dia] >> and mill a small recess in the lid, leaving only about 0.005" of metal >> thickness. The lab would than center this in the seal. Generally, this >> gave us more consistent data. >> >> Variance of data - either approach is prone to variation if everything is >> not absolutely perfectly cleaned and performed. You did not say how many >> samples you ran at each lab. Hopefully, you ran 4-6 at each. As a >> minimum, >> 3, so you could throw out the low and high, and keep the middle. I am >> sorry, but to test 1 or 2 is almost fruitless due to variance. >> >> To the adhesive - Two major potential issues come to mind. >> >> First - if you take a great adhesive and improperly process it, you end up >> with garbage. The 84-1LMI is a very good adhesive which has been used by >> many firms in Space, Mil, and Implantable medical applications. It can >> meet >> the requirements of Mil Std 883, TM 5011 when properly processed. That is >> a >> very good material to use - if properly processed!! Depending upon the >> date >> of assembly, it was THE material to use. [I am not in any way associated >> with Ablestik/Henkel, but I have indeed used this material on many >> hybrids, >> including many space applications, one of which is still in the Saturnian >> system] >> >> Second - No matter how well you process the adhesive, if the pre-seal >> conditioning [pre-seal bakes, vac bakes, package [and lid] cleanliness >> [and >> bakes] is not adequate, one will end up trapping trash inside a hermetic >> package. >> >> Yes the limit is 5000PPM. The real issue is [if the RGA testing is >> accurate] what other ionics and corruption do you have inside the package >> to >> combine with the water?? >> >> Whether adhesive is allowed or dis-allowed is generally addressed by the >> detail specification for the device. I do indeed know of quite a few >> Space >> level parts that have adhesive inside.... properly processed adhesives... >> >> No one can really give you a definitive answer, at arms length, such as >> this, but here are my free two bits ... >> >> >> I would have to go back and review my dew point knowledge, but I strongly >> suspect the 28000 PPM is bogus [unless device assembly is really sloppy - >> see below]. You should be able to achieve well under 2000 PPM without too >> much grief if it is a TO-5 or smaller package [properly processed]. >> >> My fear is that you are buying a commercial grade device, that was >> assembled >> and processed as a commercial grade device, having no RGA requirements. >> Therefore, the adhesives were likely not processed in a manner which would >> give you good RGA results. To make a poor analogy, it is like you are >> buying a standard 75W incandescent bulb and banging it around as though it >> were a Rough Service bulb. Yes, some will survive the abuse, but most >> will >> have the filament destroyed almost immediately because they were not >> constructed in a manner which would offer a much greater likelihood that >> they would pass testing. That may be the situation you are in. Sorry. >> >> Hopefully Inge is eyes-open and he can add a few comments as well. >> >> >> Steve Creswick >> Sr Associate - Balanced Enterprise Solutions >> <http://www.linkedin.com/in/**stevencreswick<http://www.linkedin.com/in/stevencreswick> >> > >> http://www.linkedin.com/in/**stevencreswick<http://www.linkedin.com/in/stevencreswick> >> >> >> >> >> -----Original Message----- >> From: TechNet [ <mailto:[log in to unmask]> mailto:[log in to unmask]] On >> Behalf >> Of Watson, Howard A >> Sent: Thursday, December 13, 2012 6:24 PM >> To: [log in to unmask] >> Subject: [TN] Component issue - epoxy die attach >> >> 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. 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