TECHNET Archives

December 2012

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Guy Ramsey <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Guy Ramsey <[log in to unmask]>
Date:
Fri, 14 Dec 2012 14:40:50 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (512 lines)
This is why very few engineers and scientists are politicians.

See what happened when they asked Einstein to "rule" Israel. 
http://www.youtube.com/watch?v=Dtk_gChLchw&feature=related




-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Graham Collins
Sent: Friday, December 14, 2012 1:40 PM
To: [log in to unmask]
Subject: Re: [TN] Component issue - epoxy die attach

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. Any use of this information by anyone other 
> than the intended recipient is prohibited. If you have received this 
> transmission in error, please immediately reply to the sender and 
> delete this information from your system. Use, dissemination, 
> distribution, or reproduction of this transmission by unintended 
> recipients is not authorized and may be unlawful.
>
>
> ______________________________________________________________________
> 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 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 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 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] 
______________________________________________________________________

ATOM RSS1 RSS2