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TechNet E-Mail Forum <[log in to unmask]>, Inge <[log in to unmask]>
Date:
Fri, 29 May 2009 17:50:08 +0200
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Steve, I'll send a snapshot on my cat in a few minutes, to show you how 
interested she was....I feel utterly insulted..
Inge


----- Original Message ----- 
From: "Inge" <[log in to unmask]>
To: "TechNet E-Mail Forum" <[log in to unmask]>; "Steve Gregory" 
<[log in to unmask]>
Sent: Friday, May 29, 2009 5:39 PM
Subject: Re: [TN] Looking for opinions on separation/delamination between 
copper land and dielectric material.


> Steve, do you recommend this if the cat is a Maine Coon ?
> I showed the tube to my cat, but she just jawned and looked bored. 
> Apparently, this was beyond her dignity. I tried to yoddle myself, but she 
> looked down with pain and trotted away.
> Inge
>
>
> ----- Original Message ----- 
> From: "Steve Gregory" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Friday, May 29, 2009 4:57 PM
> Subject: Re: [TN] Looking for opinions on separation/delamination between 
> copper land and dielectric material.
>
>
> Okay Inge, here's some light entertainment.
>
> As engineers, I know many of you have struggled with the complex
> problems of trying to teach your cats how to yodel.
>
> So, thanks to the wonderful technology of the internet and two engineers
> named Paul and TJ, here is a short video called: "An Engineers Guide to
> Cat Yodeling" which hopefully solve your dilemma:
>
> http://www.youtube.com/watch?v=aEjKk5Kt3rs&feature=channel
>
> Enjoy B^)
>
> Steve
>
> ---------------------------------
> On May 29, 2009 Inge wrote:
>
> Looking forward to the TN Friday light entertainments....have nothing
> myself at the moment
>
> Inge
>
>
>
>
>
>
> ----- Original Message -----
> From: "Werner Engelmaier /*" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Friday, May 29, 2009 2:43 PM
> Subject: Re: [TN] Looking for opinions on separation/delamination
> between copper land and dielectric material.
>
>
>> Ni hao charming,
>> That separation can occur during cooling from solder reflow [if too
>> fast=thermal shock] or in your T-shock test [would have been good to
>> give details.
>> Your TSSOP leads are likely Alloy42 [=very stiff] and are very stubby
>> [=very stiff] with SAC-solder  [=very stiff].
>> In T-shock it is NOT any CTE-mismatch that causes your problem [even
>> though it does not help, and may cause reliability problems with the
>> product], but the thermal gradients resulting from T-shock and causing
>
>> component/PCB warpage.
>>
>> How to improve on that? EASY, do not do T-shock in production [slow
>> cooling rate after reflow to 1.5C/sec or less] and in testing go less
>> severe or no T-shock at all.
>>
>> Werner
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: Charming Chan <[log in to unmask]>
>> To: [log in to unmask]
>> Sent: Fri, 29 May 2009 4:45 am
>> Subject: [TN] Looking for opinions on separation/delamination between
>> copper land and dielectric material.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> Hello All,
>>
>> Our guys ran a thermal shock test to verify solder joint reliability
>> of a TSSOP component. The micro-section shows that there is a minor
>> crack at the toe side of the solder joint and a
>> separation(delamination) between the copper land and the dielectric
>> material.
>>
>> My question is,
>>
>> Where did the separation/delamination occur? PCB fab house, PCB
>> assembly house, or thermal shock test?
>>
>> If the separation/delamination occurred at pcb fab house, then, what's
>
>> the possible root cause gonna be?
>>
>> If the separation/delamination occurred at thermal shock test or pcb
>> assembly house, then, is it caused by CTE mismatch between pcb base
>> material, solder alloy, and gull-wing footprint? How to improve on
> that?
>>
>> Brain storm, and any input is appreciated.
>> I will get the micro-section picture posted once I get it. Thank you
> all.
>>
>> Best Regards
>> Charming Chan
>>
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