Subject: | |
From: | |
Reply To: | TechNet E-Mail Forum. |
Date: | Tue, 1 Oct 2002 20:18:59 -0400 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Hi Eric,
can you point us to the mechanical specs of the components you have problems
with? One picture (drawing) is worth a thousand words.
Or post some pictures of the failed assemblies somewhere, for us to see. You
can contact Steve Gregory for that.
Salutations,
Ioan
-----Original Message-----
From: Eric Castonguay
To: [log in to unmask]
Sent: 10/1/02 6:05 PM
Subject: [TN] Dual footprint on Stacked Memories
Technet,
we are using a very special component on our pcb designs that has dual
footprint (fine pitch and BGA arrays). This component is made of two
TSOP66
stacked in tower and have mixed terminals: gull wing leads and BGA
balls.
So, both TSOP are assembled together with an interposer PCB in order to
make a stack. Bottom TSOP is weld to motherboard and high-temperature
solder (lead-free paste) is used to weld TSOP leads to the interposer
pcb.
BGA solder balls are SN96/AG4 and also interfaced with motherboard.
First, is anybody out there ever used this type of lead-free package
before? Any success?
We had many issues so far at our CM with these stacked memories: open
contacts (microfractures, missing solder, poor wettability) and
misaligned
components. We think it is mainly because non-eutectic balls doesn't
reflow
with standard temperature profile (60 sec. at 183 deg. C with peak at
220
deg. C). Hence creating poor joints.
Regards,
Eric Castonguay
Hyperchip
------------------------------------------------------------------------
---------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
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/html/forum.htm for
additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
------------------------------------------------------------------------
---------
---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
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/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
|
|