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Subject:
From:
Douglas Pauls <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Fri, 14 Dec 2012 14:26:00 -0600
Content-Type:
text/plain
Parts/Attachments:
text/plain (596 lines)
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
>
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