Hi Steve,

The symmetry looks okay.
However, my opinion, there's either trouble or cost or both in the copper
weights and possible core/pre-preg stacks.

Looks like getting the copper weights is the challenge.

If impedance is a key factor then there may be fun in getting equal resin
contents.

Assuming the 0.8mil is resist then:
1- 1.5oz
   8.5mil Pre-preg.
2- 1oz
   3 mil core, double copper
   needs all the support it can get, hopefully between 2 planes! Okay for
copper so far
3- 1oz
   12mil pre-preg, made of say a 2116/7628
4- 0.5oz
   12 mil core -
   could possibly be a sandwich of 2 single sided cores and a pre-preg to
ease availability of cores with right copper
5- 1oz
   4mil pre-preg
6- 0.5oz
   6mil core - double copper
Etc. repeated symmetrically


Best Regards

David Greig
______________________________
GigaDyne Ltd
Buchan House
Carnegie Campus
Dunfermline KY11 8PL
United Kingdom
t: +44 (0)1383 624 975
______________________________

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Stephen Gregory
Sent: 25 February 2005 18:54
To: [log in to unmask]
Subject: [TN] Manufacturability of PCB Stack-up...

Happy Friday All!

I've posted a drawing of a PCB layer stack-up at:

http://www.stevezeva.homestead.com/files/Stackup.jpg

I'd like to verify its manufacturability.  The reason for the verification
is that there are dielectric thicknesses that vary quite a bit from layer to
layer.

Can anybody comment on this?

Kind regards,

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