As once noted from a quartet of famous resources "Let it B".
Dewey

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Theodore J Tontis
Sent: Friday, November 22, 2013 9:11 AM
To: [log in to unmask]
Subject: [TN] PCB stack up question

I have a 6 layer stack up specified on my gerbers as:

0.0004 mil solder mask
0.0014 mil top layer 1oz copper
0.0086 mil 2 X 2116 prepreg
0.0014 mil inner 1 1oz copper
0.0140 mil core
0.0014 mil inner 2 1oz copper
0.0086 mil 2 X 2116 prepreg
0.0014 mil inner 3 1oz copper
0.0140 mil core
0.0014 mil inner 4 1oz copper
0.0086 mil 2 X 2116 prepreg
0.0014 mil bottom layer 1oz copper
0.0004 mil solder mask

0.0620 mil total stack up +/- 0.006

Our CM's vendor is requesting I change either
A: adjust the 14mil core to 12mil to meet 62±6mil finished thickness.
B: relax the finished thickness to 65±6mil..
C: control the board thickness with 62±6mil exclude the solder mask thickness.

Their stack up is as follows:

0.0005 mil solder mask
0.0020 mil top layer 1oz copper
0.0091 mil 2 X 2116 prepreg
0.0012 mil inner 1 1oz copper
0.0142 mil core
0.0012 mil inner 2 1oz copper
0.0085 mil 2 X 2116 prepreg
0.0012 mil inner 3 1oz copper
0.0142 mil core
0.0012 mil inner 4 1oz copper
0.0091 mil 2 X 2116 prepreg
0.0020 mil bottom layer 1oz copper
0.0005 mil solder mask

0.0649 mil total stack up +/- 0.006

I got my stack up from a local vendor I've worked with in the past.
Our CM has measured some of their bare boards at 0.070 and 0.071 mil thick.

Which stack up is correct or am I missing something important?


Ted T.


Theodore J. Tontis CID
Senior Manufacturing Engineer
[cid:[log in to unmask]]<http://www.eaton.com/>
11131 Adams Road
Franksville, WI 53126
Office 262-835-1552
Cell 262-510-3145
Fax 262-835-1544


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