The smaller grain size will definitely do both for you.  Small grain copper 
etches faster, the side walls of the traces are cleaner and the etch factor is 
lower.  Looking at the traces under the scope you should see the difference with
no difficulty.  The smaller grains are also closer so there is less porosity and
higher flexibility.  

Good Luck and have fun.

Chuck Brummer 
Acuson


______________________________ Reply Separator _________________________________
Subject: Cu Foil Grain size
Author:  [log in to unmask] at ccUnix
Date:    7/22/97 12:53 AM



Hi,

Does anyone know how would the grain size of the matt surface of the Cu 
foil (say 1/2 oz)
affect the etching performance, peel strength and any other properties of 
the PCB?

The reason is we have a Cu foil supplied from Japan with very fine grain 
nodules < 1um.
Then another from Korea with larger grain at the matte surface (1 - 2um) 
under the SEM.

Smooth side for this Korean foil is also rougher.

I read one article from the Japan supplier that the smaller the grain the 
faster the etching rate, thus easier and better etching especially for 
fine-lines.
Any Comment?

Richard


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