Subject: | |
From: | |
Date: | Thu, 20 Mar 97 16:06:49 PST |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Hi Patty,
I do not have a solution for your problem, but here are some questions
that may help lead you to a solution.
From your description, you have core materials on the outer layers?
Are the 2 / 9 cores of the same core thickness and manufacturing lot?
Were the 2 / 9 cores imaged and etched at the same time as the
remaining cores?
You may have a problem with your tooling system in the inner layer
imaging operation. (a brief description of your system may help)
Are you sure that this is a "shift" and not a "shrinkage" of the 2 / 9
images? If there is a shrinkage, you will need to compensate the 2 /
9 CAD data. If there is an image shrinkage of the 2 / 9 layers, the
"shift" should be symmetrical around the center of the panel.
Good Luck,
Joe Brunetto
Process Engineer
Zycon Corporation
______________________________ Reply Separator _________________________________
Subject: FAB(Shifting Layers)
Author: [log in to unmask] at corp
Date: 3/20/97 12:47 PM
We are experincing a reaccuring problem with our lamination process on 10
layer projects with the following stackup:
1. 1 oz copper on all 5 FR4 5 mil sheets;
2. 3 sheets of PGFK1080 2.5mil prepreg in each gap (total of 7.5mils each
gap);
3. Grain of prepreg is in the same direction;
4. finished thickness 69 mils;
5. layers 2-4 & 7-9 are signal layers;
6. layers 5&6 are ground/VCC planes.
Problem: We are consistently seeing layers 2 and 9 shift 3-4 mils more than
the other layers (3:4, 5:6, & 7:8). Layers 3:4, 5:6, & 7:8 all align well
with each other and the outermost sheets are shifted to the right by this 3-4
mils. Once layers 1 and 10 are imaged onto the drilled panel, they also line
up well with the innermost layers (3:4, 5:6, & 7:8). We are losing panels due
to annualar rings less than 2 mils on layers 2 & 9 (Mil-P-55110).
We would appreciate any suggestions from those who have seen similar
occurances.
Patty Causey / Marty W. Sheppard
Process Engineering Section
email address: [log in to unmask] /
[log in to unmask]
Phone: (912) 926-9473(9632)
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]> *
* with <subject: subscribe/unsubscribe> and no text in the body. *
***************************************************************************
* 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 subscribe/unsubscribe send a message <to: [log in to unmask]> *
* with <subject: subscribe/unsubscribe> and no text in the body. *
***************************************************************************
* 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] *
***************************************************************************
|
|
|