Subject: | |
From: | |
Date: | Mon, 27 Jan 97 12:24:35 PST8 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Brett / All,
One possible cause for Dish-Downs is a mouse bite or pinhole in the
rubber of the Resist Laminator roll . A small vacancy in the rubber
will look like a bubble on the laminated panel surface. If a circuit
falls on the bubble etchant will under cut and cause a dish down.
Typically , rollers with this condition are damaged when 2 panels
are overlapped in the cleaning cycle and Sulfuric acid is trapped
between them . The acid is squeezed out and deposited on the rollers
during resist lamination. Sulfuric acid will eat a hole in silicon of
the rollers leaving a small holes.
Mike Covel
HMSC ,Tucson
______________________________ Reply Separator _________________________________
Subject: FAB-Dish downs in copper circuits
Author: [log in to unmask] at CCGATE
Date: 1/27/97 8:58 AM
Good Morning,
Recently a customer had a field failure in which and internal circuit
trace
burned through. After a failure analysis was done, a cross-section determined
that at the point of failure there was a dish-down or vertical thinning of
the trace.
This defect was not picked up at innerlayer inspection as the primary
focus
is on shorts, breaks and mouse-bites. The customer would like to know if
there
is any industry data showing the possible frequency of such a defect.
How do I give a cause/corrective action for a defect Im not sure I can
consistantly
detect?
Thank you for your help.
Brett Austin
Nationwide Circuits Inc
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To unsubscribe from this list at any time, send a message to: *
* [log in to unmask] with <subject: unsubscribe> and no text. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
***************************************************************************
|
|
|