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December 2000

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Subject:
From:
Hann Pang <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 5 Dec 2000 12:14:39 -0600
Content-Type:
text/plain
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text/plain (93 lines)
Hi Hans,
In the process of  mounting flip chips or chip scale packages to PCBs,
there's a need to fill the gap between the  chip and the board with an
adhesive to minimise the CTE mismatch between the board and the die.  this
is known as underfilling.  and the reason i'm asking is because reliability
of the solder joints is compromised when there is a lot of outgassing from
the board  into the adhesive material while curing.  If there was
pretreating of the boards in an oven, this problem would be greatly
reduced.  thanks

Hann






Hans Hinners <[log in to unmask]> on 12/05/2000 12:00:15 PM


To:   "'TechNet E-Mail Forum.'" <[log in to unmask]>
      Hann Pang/US-Corporate/3M/US@3M-Corporate
cc:
Subject:  RE: [TN] Query: industry standard for pretreating PWB/PCB before
      underfilling?



Hann,

Help me out here.  By underfill do you mean an application of an RTV or is
it some other process?

Hans

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Hans M. Hinners
Process Engineer
Toppan Electronics, Inc.
770 Miramar Road
San Diego, CA 92126
(858) 695 - 2222 ext. 241
(858) 695 - 6823 fax
[log in to unmask]


-----Original Message-----
From: Hann Pang [mailto:[log in to unmask]]
Sent: Tuesday, December 05, 2000 9:27 AM
To: [log in to unmask]
Subject: [TN] Query: industry standard for pretreating PWB/PCB before
underfilling?


Hi
Can someone help me with the question??  Thank you very much.

I'm posting the above question as a technical marketer for 3M.  We're
currently working on underfills and the question is posed in consideration
of the outgassing of the PCBs.
If there is'nt a standard, then the next question is; typically, what are
the pretreating conditions if there is any pretreating at all?

Thanks and regards,

Hann Pang
Technical Markerter

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