28 Dec
2006
28 Dec
'06
7:16 p.m.
Grant Stockly wrote:
At 05:26 PM 12/28/2006, you wrote:
Most modern boards that use BGA's (ball grid arrays) are X-ray'ed to
check for assembly defects. There must be some reasonable tolerance to
X-rays by today's current technology chips. I'm currently working with
Sony on a video project and have had our prototype board exposed
5 times already (testing various versions of a BGA chip). Anyone know
what the exposure might be from the BGA inspection stations? Anyone
heard of a limit to how many times a board can be exposed before I get
worried?
Bob
X-rays can damage ICs. While searching for
information
on possible risks to electronics from x-ray security
screening, I encountered a second-hand reference to a
study to determine the safest X-ray wavelengths and
exposure for nondestructive testing of
high-reliability
ICs. X-rays can inject faults into the silicon
lattice,
which degrade the quality of the transistors. I think
the
exposure that can be tolerated is affected by geometry
(e.g., transistor size), so it might not be as much of
an
issue for older electronics as it is for newer stuff.
Anybody know more?