Steve,

In a CRC you can find a table of resistance of copper wire listed by
diameter. It is expressed per unit length (feet, inches or meters), so
the units are mass(diameter) and length.  I would expect that
ohms/meter^2 is correct.

I have been successfully calcualting the mass of the trace (width and
thickness)and matching the wire diameter mass then multiplying by the
length of the trace.

I have been able to predict the total resistance of traces pretty well.
You usually have to graph out the resistance of the wire diameter and
find your crossection area on the curve but it will get you close.

Doug Jeffery
Electrotek, Inc.

You wrote:
>
>Greetings All,
>
>I am looking for the formula to predict DC-Etch readings prior to
oxide.
> I know IPC-MF-150F lists the resistivity of 1 oz. As .162
>Ohm-gram/meter^2, however the only formulas I have seen for
determining
>the resistance of a conductor incorporate Rho (resistivity constant)
as
>Ohm-meter.  Any and all help is greatly appreciated.
>
>Steve Stone
>Process Engineer
>Altron, Inc.
>978-933-1735
>[log in to unmask]
>
>##############################################################
>TechNet Mail List provided as a free service by IPC using LISTSERV
1.8c
>##############################################################
>To subscribe/unsubscribe, send a message to [log in to unmask] with
following text in the body:
>To subscribe:   SUBSCRIBE TECHNET <your full name>
>To unsubscribe:   SIGNOFF TECHNET
>##############################################################
>Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
additional information.
>For the technical support contact Dmitriy Sklyar at [log in to unmask] or
847-509-9700 ext.311
>##############################################################
>

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
##############################################################