Hello all,
     I have a problem in etching copper with ferric
chloride. The copper(20um) is deposited on a glass
epoxy substrate. Shipley 1813 resist was used to
define the patter and as etching mask, feature size
~60um. The copper substrate was etched in ferric
chloride solution @50C, under microscope it is shown
that some of the pattern was over-etched while others
are untouched.

     The photoresist is around 3um thick(S1813),
exposure dosage ~40mJ/cm2, soft bake for 8 mins@95C,
developed for 100sec, and post develop bake for 30mins
before being put into etchant.

     Any suggestions and help are appreciated. Thanks.

leidong



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