Appeal No. 1998-1224
Application No. 08/465,077
etch rate of the solution decrease “to less than 0.01
mil/min when the desired etch is complete.” We shall
refer to this rate as the terminal etch rate of the
solution. Claim 25, the sole independent claim on
appeal, is representative:
25. A method for etching a curved copper film to
produce a patterned film with fine-line elements
etched to a tolerance of about + 0.25 mil on all
lines, the patterned film being a frequency
selective surface suitable for use in a radome,
comprising the steps of:
(a) patterning a photolithographic mask
deposited on the copper film to expose line widths
approximately 1 mil narrower than the desired final
width; and
(b) etching the exposed copper to create
fine- line elements in the film to a tolerance of
about + 0.25 mil on all lines by immersing the
masked film in a quiescent, dilute cupric chloride
etching solution having at least about 125 gm/1NaC1
sufficient to eliminate any migration or
electrolytic effects, the etch rate of the solution
declining to less than 0.01 mil/min when the desired
etch is complete.
All of the claims on appeal stand rejected under the
first paragraph of 35 U.S.C. § 112 for lack of an
adequate written description in the specification of
appellant’s invention as claimed.
After having considered the entire record in light
2
Page: Previous 1 2 3 4 5 6 7 Next
Last modified: November 3, 2007