We need some expert assistance using the IPC-4101 specification for
fabricating bare boards. The group seems to have very knowledgeable fabricators
and designers. Please take some time and help a new member to the group help us
fabricate board more reliably.
   We recently had problems with bare boards coming in too thick (.070 - .072).
I would like to know what the minimum and maximum thickness the card should be
using the following specification. (Specification used "MATERIAL: GFN 0620 C1/C1
A2A per MIL - P - 13949F"). To ensure we receive boards that are .062 +/- .005
how should the specification read and why. (Others have suggested GFN 0590 C1/C1
A2A).

Current specification used:
       GFN 0620 C1/C1 A2A spec is as follows:
   0.0000  GFN = FR4 material with no color added.
   0.0620  0602 = .062 thick base material without copper
   0.0030  C1/C1 = 1oz. copper each side
   0.0000  A2A = Quality issues not effecting thickness
   0.0030  60/40 Tin Lead
   0.0020  Solder masking (LPI)
   ----------
   0.0700 Total thickness Max.


   We would like to start using IPC-4101 specification in our fabrication
control drawings. To accomplish the preferred result of .067 +/- .005 here are
the specification we derived from the 4101. Please your recommendations on how
we can get yields with our preferred PCB thickness (IPC-4101 K21 0620 C1/C1 KA),
(IPC-4101 L21 0590 C1/C1 AA) or other.

Maximum dimension specified:
   IPC-4101 K21 0620 C1/C1 KA  spec is as follows:
   0.0000  K21 = FR4 material with no color added.
   0.0620  0620 = .062 thick base material with copper
   0.0000  C1/C1 = 1oz. copper each side
   0.0000  A2A = Quality issues not effecting thickness
   0.0030  60/40 Tin Lead
   0.0020  Solder masking (LPI)
   ----------
   0.0670 Total thickness Max.

   IPC-4101 L21 0590 C1/C1 AA spec is as follows:
   0.0000  L21 = FR4 material with no color added.
   0.0590  0590 = .059 thick base material without copper
   0.0030  C1/C1 = 1oz. copper each side
   0.0000  A2A = Quality issues not effecting thickness
   0.0030  60/40 Tin Lead
   0.0020  Solder masking (LPI)
   ----------
   0.0670 Total thickness Max.

   How do you build multi-layer cards using IPC-4101 specification. Our intent
is to build boards with the same thickness as the double sided by using the
IPC-4101 specification with one ounce copper on external layers and one or half
ounce internal layers. We have difficulty extracted this information from the
IPC-4101 document. Please enlighten me with your expert knowledge by sending
build-up of the specification similar to the specification s shown above. Thanks
in advance for your much needed help.


   Thanks,
   Tom
   Document Services Manager / CAD Manager
   Inter-Tel Integrated Systems, Inc.
   7300 W. Boston Street
   Chandler AZ. 85226

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