TECHNET Archives

December 2008

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:
"Stadem, Richard D." <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Stadem, Richard D.
Date:
Tue, 23 Dec 2008 08:14:58 -0600
Content-Type:
text/plain
Parts/Attachments:
text/plain (115 lines)
I don't know how well they work, but Kester and others make a reflowable
underfill. 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
Sent: Monday, December 22, 2008 5:34 PM
To: [log in to unmask]
Subject: Re: [TN] Underfill, inhibition due to leftover activators in
the flux residue

Phil,
Add Indium as an underfill supplier. 

Bev
RIM

----- Original Message -----
From: TechNet <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Sent: Mon Dec 22 18:02:18 2008
Subject: [TN] Underfill, inhibition due to leftover activators in the
flux residue

I have made quite a few test samples and discovered that a certain
underfill material will exhibit inhibited cure when it comes in contact
with solderpaste flux residues at the center of a very dense BGA
component.
The rest of the underfill beneath the BGA will harden like normal.
We don't clean nor plan on starting to clean our assemblies.
DVT testing does not show any defects due to underfill adhesion.


Background:
We used a four up ABAB panel which goes through SMT twice.
BGAs only passing through the oven once consistently show the problem.
Two passes through the reflow oven (ABAB flip) and the problem goes
away.
This means that  half of our test samples still have soft material in
the pocket at the center where the power ground pins are located.
We measure peak temperature in this area and have found that raising the
peak temperature helps quite a bit but does not eliminate the inhibition
entirely.
The manufacturers of the paste and the underfill acknowledge the issue
but do not have a solution.

Has anyone else run into similar compatibility issues with a paste and
underfill?

In the event that we cannot work out the root cause, and decide to make
a change, I am trying to come up with a list of all the manufacturers of
underfill.

So far I have found 8 major underfill manufacturers but would appreciate
knowing about more if there are any.

3M
Ablestik
Epotek
Henkel
Hysol
SP&S
Sunstar
Zymet

Thanks in advance,

Phil

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 To
unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or
(re-start) delivery of Technet send e-mail to [log in to unmask]: SET
Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the
posts: send e-mail to [log in to unmask]: SET Technet Digest Search the
archives of previous posts at: http://listserv.ipc.org/archives Please
visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for
additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------------------------
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.

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 To
unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or
(re-start) delivery of Technet send e-mail to [log in to unmask]: SET
Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the
posts: send e-mail to [log in to unmask]: SET Technet Digest Search the
archives of previous posts at: http://listserv.ipc.org/archives Please
visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for
additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2