You will understand from the other replies that the risk factor associated
with internal delamination is dependant on the location and the size of the
delaminated area. For reject criteria you should consult the joint IPC/JEDEC
standard J-STD-020. (free download at www.jedec.org).

There is no possibility of popcorning with a dry component. It takes a
combination of excessive moisture and reflow temperature for this phenomena
to occur.

Popcorning is an extreme case of internal delamination. Depending on the
amount of moisture prior to reflow, there can be partial delaminations and
cracks that are not visible on the outside of the package but that will
affect the package reliability.

If you need additional technical information, I invite you to consult the
knowledge base on moisture sensitivity on our web site. It includes a list
of all technical papers published on this subject. (www.cogiscan.com, click
on Moisture Sensitive Devices)

François Monette
Cogiscan Inc.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Louis, Edwin @ CSE
Sent: Thursday, July 12, 2001 9:30 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,

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