John Perry, dispatch the fleet to Halifax. Bombard from orbit. In most cases, I am simply looking for clarity before making an edict. Failed to do that once and ended up destroying the entire star system. So, I check first. Doug Pauls From: Graham Collins <[log in to unmask]> To: <[log in to unmask]> Date: 12/14/2012 12:41 PM Subject: Re: [TN] Component issue - epoxy die attach Sent by: TechNet <[log in to unmask]> 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:[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 > > > > > > -----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]> > mailto:[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 > > > > > -----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. 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] > ______________________________________________________________________ > > --------------------------------------------------------------------- > This transmission (including any attachments) may contain confidential > information, privileged material (including material protected by the > solicitor-client or other applicable privileges), or constitute non-public > information. 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