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September 2012

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Subject:
From:
Paul Edwards <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Paul Edwards <[log in to unmask]>
Date:
Wed, 26 Sep 2012 08:48:31 -0700
Content-Type:
text/plain
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text/plain (148 lines)
I would have thought that a re-balling would have increased the IML thickness due to the increase in thermal cycles... But since the diffusion rater in Ni is small I can see that that may not be an issue...

I guess technically speaking I am interested in the effects on that layer of solder that is leftover from the solder ball removal/cleaning process that ends up being the solder substrate for the paste or ball of the ball attachment process...

Paul

Paul Edwards
Process/Quality Engineering
Surface Art Engineering


-----Original Message-----
From: Vladimir Igoshev [mailto:[log in to unmask]] 
Sent: Wednesday, September 26, 2012 8:38 AM
To: TechNet E-Mail Forum; Paul Edwards
Subject: Re: [TN] Leaded Paste and Lead Free BGAs - Do they mix?

Hi Paul,

We had several of them for analysis over years and it's never been an issue. Intermetallics at the UBM interface is always thinner compared to the board side and reballing doesn't noticeably change that.
Regards,

Vladimir

SENTEC Testing Laboratory Inc.
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca

-----Original Message-----
From: Paul Edwards <[log in to unmask]>
Sender: TechNet <[log in to unmask]>
Date: Wed, 26 Sep 2012 08:26:15 
To: <[log in to unmask]>
Reply-To: TechNet E-Mail Forum <[log in to unmask]>,
        Paul Edwards
	<[log in to unmask]>
Subject: Re: [TN] Leaded Paste and Lead Free BGAs - Do they mix?

Also,

Does anyone have any papers or studies on the effects of the re-balling process on the inter-metallic layer at the BGA package pad and the ball?

Paul

Paul Edwards
Process/Quality Engineering
Surface Art Engineering


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Paul Edwards
Sent: Wednesday, September 26, 2012 8:19 AM
To: [log in to unmask]
Subject: Re: [TN] Leaded Paste and Lead Free BGAs - Do they mix?

Yup...I agree...

But when legal steps in, you can't squeeze blood out of a turnip...

Paul

Paul Edwards
Process/Quality Engineering
Surface Art Engineering


-----Original Message-----
From: Stadem, Richard D. [mailto:[log in to unmask]] 
Sent: Wednesday, September 26, 2012 8:13 AM
To: TechNet E-Mail Forum; Paul Edwards
Subject: RE: [TN] Leaded Paste and Lead Free BGAs - Do they mix?

The reliability issues associated with re-balling are pretty much confirmed to be a non-issue if performed properly. There are many good papers on that subject.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Paul Edwards
Sent: Wednesday, September 26, 2012 10:09 AM
To: [log in to unmask]
Subject: Re: [TN] Leaded Paste and Lead Free BGAs - Do they mix?

Bob,

Have run into the same situation...

In our case the customer was unable to get the product with leaded balls...
They did not want spend the time and cost to have a special run of chip manufactures and were too concerned with the cost and undefined reliability issues associated with re-balling...

Paul 

Paul Edwards
Process/Quality Engineering
Surface Art Engineering

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Robert Kondner
Sent: Tuesday, September 25, 2012 5:26 PM
To: [log in to unmask]
Subject: [TN] Leaded Paste and Lead Free BGAs - Do they mix?

Hi,

 

I have a customer using leaded paste with lead free BGAs. I think they want to have the balls NOT collapse for better optical inspection.

 

Sounds like a really bad idea to me but I have no explanation where I can say as why.

 

Can anyone make suggestions either way?

 

Thanks,

Bob K.



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