Louis,

Here is my 2 cents.

Popconing is caused by the evaporation of moisture inside the Plastic mold
compound, die attach paste (and BT substrate for BGA package). By baking the
PEMs (at 100-125C, 8-24 hrs) to dry out the moisture from the plastic
material, there wouldn't be any popconning. For the internal delamination,
die top delamination parts should be rejected. If the delamination is
between the die and the Leadframe (Substrate in the case of BGAs), 10%
should be tolerable. Pls note that the delamination between die and the
Leadframe/substrate will reduce the thermal dissipation capability on the
PEMs.

Hope this help.

TL

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Louis, Edwin @ CSE
Sent: Thursday, July 12, 2001 6:30 AM
To: [log in to unmask]
Subject: [TN] PEMs


If one receives PEMs from the manufacturer which are supposedly dry and
handled correctly but are found to have internal delamination
by acoustic spectroscopy, whether this is an automatic sentence of
popcorning when the devices are put through convection reflow. Is there air
inside the part that can cause popcorning of a dry part when no outward
signs of delamination or popcorning is visible.Also,

----------------------------------------------------------------------------
-----
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
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 delivery of Technet send the following message: SET
Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases >
E-mail 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 1.8d
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 delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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
---------------------------------------------------------------------------------