Morning All!

I submitted a question to Altera via their email support center about x-ray
inspection possibly
damaging a EPM7256EEFI100-7 device. The device is a EEPROM made using an
advanced
CMOS process.

Here is our exchange so far:

>Request No: 10515187 Status: Close-Pending
>Date Opened (PDT): 9/26/2005 07:24
>AM Date Closed (PDT):
>Inquiry Type: Product Question
>Device Family:   Device:
>Title: X-ray inspection of devices
>
>Description: I am doing x-ray inspection of a EPM7256AEFI100-7 device
after board assembly.
>The PCB has a 1.27mm thick copper core in the center of it, so it requires
that a high kv x-ray must
>be done in order to see the solder connections of the device. The x-ray
source power is around
>120-130kv. Will this x-ray power level damage the device?
>
>Thank-you,
>
>-Stephen Gregory-
>Process Engineer
>LaBarge Inc.
>
>
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>
>Updates  1 - 2 of 2  Add an Update / Previous / Next
>
>Date Created (PDT) 9/27/2005 07:44 PM
>
>To Customer:
>
>Hi Stephen,
>
>Typically assembly uses 90KV using 10 to 20mA with a few second for
inspection of IC package. Our
>recommendation will be a pro-rated 130KV with 7mA to 13mA for a few
second. Note that Prolong exposure
>under X-ray will definitely damage the device. I hope it's helpful to you.
>
>Best Regards,
>Daniel Cao

My question is; doesn't the figure of 90KV at 10-20mA seem pretty low?

My current Glenbrook RTX-113 operates at 35-52KV at 20-50mA, and higher-end
Glenbrook systems will
pump 70-90KV at 90-100mA. Right now, I'm using a Fein Focus Tiger 160 for
x-ray inspection of some copper
cored assemblies that we're building because I have to, that's the only way
we can inspect the BGA's. The
copper core in the PCB won't allow x-ray of the BGA's unless you use a
system that can penetrate the core.

But if these devices can be damaged at such a low voltage (if indeed
Daniel's figures are correct), shouldn't
Altera issue some sort of warning to their customers about x-ray damaging
the devices? After all, there will
be a lot of customers using x-ray for inspection.

Kind regards,

-Steve Gregory-
Senior Process Engineer
LaBarge Incorporated
Tulsa, Oklahoma
(918) 459-2285
(918) 459-2350 FAX
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