Hi,
Many years ago(+/- 6 years) we designed 14 layers into a 1.6 thick pcb using
1 ounce copper on the internal layers, sadly the manufacturing houses
experienced "copper spreading" on the internal layers. The explanation
provided was that squeezing 14 layers into 1.6mm pcb was causing the
internal layer copper to spread sideways. We were than advised to consider
0.5 ounce(17u) copper. We changed to 0.5 ounce and NEVER had a problem
since. Using that as an argument I would than assume using 2 ounce copper
could have made that pcb almost impossible to manufacture, than again it
also depends on the number of layers.
regards
Billy Bharath

-----Original Message-----
From: Sanchez-Benavides Erika
[mailto:[log in to unmask]]
Sent: Wednesday, April 06, 2005 2:12 PM
To: [log in to unmask]
Subject: [DC] PCB TECHNOLOGY (2 oz copper)


Hello all,
One of our PCB suppliers came out with a PCB design that have 2 ounces
of copper on all layers. Until now we have worked with PCB that have 2
ounces of copper only on the exterior layers, and only one ounce of
copper on the interior layers.

We do not have experience working with PCBs with 2 ounces of copper on
all the layers.
Would you mind helping us to gain more knowledge regarding these PCBs?
Are there any risks associated with this design: thermal events,
concerns, things that we should be aware of?

Thanks in advance,

..........................................................

Kind regards
Erika E. Sanchez
PCB Designer
Siemens VDO
Internet: http://www.siemensvdo.com

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