Dennis,
I agree with Steve's comment on the maximum layer counts for the
specified thicknesses. However, it goes several steps further.
The key to having more than the noted layer count is the PCB facility
you use or plan to use and the H/W they have to facilitate such
non-standard recipes.
1. Not all shops can process cores around .004 to .006 mil range.
Even if they claim to do so, they will have a high scrap rate
processing the thin core material. In-turn, this cost is passed
onto the customer. The chemistries are not the limitations, but
the mechanics.
2. You may end up using .5oz Cu on all layers, which may not work
into your Voltage requirements (2.5, 3.3, 5 VDC).n
3. The capital equipment needed at Lamination may not be available.
You need proper temperature, pressure and vacuum controls
to ensure minimal mis-registration. If using 1-ply constructions,
you may be faced with resin starvation, in turn showing up as
delamination in your PCA processes.
Again, I'm only touching the surface of what needs to be looked at.
There are numerous variables that play into how many layers can be
achieved with standard thicknesses.
Try to deviate outside the normal .028, .062, .093, .125 mil finished
thicknesses. Nothing says you can not use .070, .075, etc. Again,
this issue is based on what standards you are designing to, ISA, PCI,
VXI, etc.
The key is the PCB facilities you end up using.
Call me should you have further questions.
John Gulley
Inet Technologies Inc
972-578-3928
______________________________ Reply Separator _________________________________
Subject: <no subject>
Author: Dennis Ward <[log in to unmask]> at Internet
Date: 11/4/98 1:28 PM
Good afternoon,
Quick question. What is the maximum amount of layers an
.062" thick boad can contain? What about .093" thick?
Thanks
Dennis Ward
Net to Net Technologies
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