Interesting you should mention pad geometry as I am currently on a break from a seminar given by a guy who recommends pad geometry of 0805 or less to be the same size as the minimum area of the metal area on the chip component.  He recommends the pad geometry to be 80% of the metal area of the component  if it is larger than a 0805.  See Murata catalog for details.   Has anyone tried this and with what success?
Tom Burek
Product Engineer


 -----Original Message-----
From: [log in to unmask] [SMTP:MIME :[log in to unmask]]
Sent: Thursday, September 09, 1999 9:28 AM
To: [log in to unmask]
Subject: [TN] Subj:  0402 Technology

 << File: ENVELOPE.TXT >>
 --------------------------------------------------------------------------  --
Hello TechNet:

I have some questions regarding 0402 technology.

1.  Has anyone optimized 0402 pad geometry?
2.  Has anyone optimized 0402 stencil aperture openings?
3.  What tombstoning issues, and other defects, have you experienced and
what preventative measures have you incorporated into the process to
eliminate tombstoning?
4.  What were predominant equipment issues related to the implementation
of
0402 technology:
        A.  Preventative maintainance schedule changes???
        B.  Calibration issues???
        C.  Operator training???
        D.  Feeder issues/identification???
5.  What are your inspection methods???
        A.  Manual
        B.  Automatic

Since we are all, for the most part being driven to smaller, lighter,
cheaper, faster, with more power we will soon encounter this technology
and
other technologies as densities increase.  Would appreciate any and all
help.  With the brain trust on this forum it is the best place to start.

If you have experience in any or all of these areas answer on the TechNet 

so
everyone can benefit.  We have done some very minor work, mainly under
scopes, with 0402 technology.  We had small, small, run product and did
hand
assembly about four years ago.

Thanks To All In Advance

Ron Hollandsworth
Operations Task Leader
ITT

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with
following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################