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May 2013

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From:
Ed Popielarski <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Ed Popielarski <[log in to unmask]>
Date:
Wed, 1 May 2013 14:44:36 +0000
Content-Type:
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text/plain (217 lines)
I concur completely with Dave.

I can "prove" it otherwise, by photomicrograph of one at the edge of the device and a CT of another.  I'll request Steve G. to post these as well.

FYI, what caused these is the devices are custom and aged quite nicely by the previous CM that failed to store them properly. The solution was to "prep" the parts remaining by coating with W/S tacky flux, reflow, wash, then place. Worked great!



Ed Popielarski
Engineering Manager


                               970 NE 21st Ct.
                              Oak Harbor, Wa. 98277

                              Ph: 360-675-1322
                              Fx: 206-624-0965
                              Cl: 949-581-6601

https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&spn=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
Sent: Wednesday, May 01, 2013 6:01 AM
To: [log in to unmask]
Subject: Re: [TN] Pic of head-in-pillow for the site

Hi George - that specific BGA was quite large so optical inspection access to see the outer row was pretty minimal which is why we used Xray assessment. I have had the same success as Ed in finding HOP defects - Xray won't find them all but it can do a fair job most of the time especially if you have any form of CT capability or oblique angle viewing. 
We used cross sectioning to confirm what we had found using Xray assessment. I'll sent the photo to Steve for posting. And we are in agreement on the inspection methodology - we use xray assessment only when optical inspection isn't value added or we suspect that our BGA  process control protocols have been compromised.

Dave



From:   "Wenger, George M. [Contractor]" <[log in to unmask]>
To:     <[log in to unmask]>
Date:   04/30/2013 08:20 PM
Subject:        Re: [TN] Pic of head-in-pillow for the site
Sent by:        TechNet <[log in to unmask]>



Hi Dave,

I'm really not a Doubting Thomas and I do believe you (because I know you) that the x-ray is of a HOP defect but I think it would be helpful to say how you know for sure that the x-ray shows a HOP defect.  I assume you know it is a HOP defect because you looked at it optically (i.e., with a mirror or fiber scope) and saw it was a HOP defect or you cross sectioned it an confirmed it was a HOP defect.  Do you have an optical image or photomicrograph of a cross section of the defect shown in the x-ray image?

The problem we've had with x-raying large high I/O count BGAs is that time consuming to scan all of the balls at a high enough magnification to find the balls that appear different from normal solder joints and once we identify the non-normal looking balls we not sure if the defect is a HOP or a non-soldered interconnection due to a solder paste stencil misprint or insufficient print.  When the defects are on outer rows we can usually tell by optical inspection what kind of defect it is. 

Regards,
George
George M. Wenger
Failure Signature & Characterization Lab LLC
609 Cokesbury Road, High Bridge, NJ 08829
(908) 638-8771 Home (732) 309-8964 Mobile
E-mail: [log in to unmask]
[log in to unmask]

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
Sent: Tuesday, April 30, 2013 5:10 PM
To: [log in to unmask]
Subject: Re: [TN] Pic of head-in-pillow for the site

Yes, the corner ball has the HOP.

Dave



From:   "Steve Gregory" <[log in to unmask]>
To:     <[log in to unmask]>
Cc:     <[log in to unmask]>
Date:   04/30/2013 04:08 PM
Subject:        RE: [TN] Pic of head-in-pillow for the site



Hi Dave!
 
Have your picture posted, it?s here:
 
http://stevezeva.homestead.com/HOP_iso1.jpg
 
It?s the corner ball, right?
 
Steve Gregory
 
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Tuesday, April 30, 2013 12:43 PM
To: Steve Gregory
Subject: Re: [TN] Pic of head-in-pillow for the site
 
Steve - please post this HOP too - same type of thing as Ed's but another example for everyone benefit: 



Dave 



From:        Steve Gregory <[log in to unmask]> 
To:        <[log in to unmask]> 
Date:        04/30/2013 10:56 AM 
Subject:        Re: [TN] Pic of head-in-pillow for the site 
Sent by:        TechNet <[log in to unmask]> 




 

Hi Ed!



Nice image! Got it posted, it's here:



http://stevezeva.homestead.com/Head-in-pillow_X-Ray.JPG



What about the void off to the right? Is there any concern about that?



Steve Gregory

Process Engineer

Kimco Design and Manufacturing

652 N. Five Mile Road

Boise, ID 83713

(208) 322-0500 Ext. 3133



From: Ed Popielarski [mailto:[log in to unmask]] 
Sent: Tuesday, April 30, 2013 8:58 AM
To: Steve Gregory
Subject: Pic of head-in-pillow for the site



Hi Steve,



I have a good X-Ray picture of a head-in-pillow that Leland would find
helpful. If you don't mind posting it for him?



Ed Popielarski

Engineering Manager





                              970 NE 21st Ct.

                             Oak Harbor, Wa. 98277



                             Ph: 360-675-1322

                             Fx: 206-624-0965

                             Cl: 949-581-6601



https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&spn
=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A
<https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&sp
n=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A> 




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