Appeal No. 2001-0570
Application No. 09/049,591
controlling the grain size and density of HSG. Accordingly, reasons the examiner, it
would have been obvious “to experiment and select the reaction temperature, the flow
rate and the time to achieve the maximum grain size of HSG (rugged polysilicon) of
about 300 angstroms, since it has been held that where the general conditions of a
claim are disclosed in the prior art discovering the optimum ranges involves only routine
skill in the art...” [answer-page 4].
By definition, 30 nm = 300 angstroms. Accordingly, Tatsumi’s disclosure of 300
angstroms as a possible grain size is a disclosure of 30 nm. Appellants agree,
admitting that Tatsumi discloses possible grain sizes down to 30 nm [brief-page 3], but
submit that at lines 22-24 of column 7, Tatsumi notes that this is the limit where grains
become too close together and surface roughness decreases.. Thus, appellants argue
that Tatsumi’s disclosure appears to say that the limitations recited in instant claim 1
are not achievable by Tatsumi’s method of rugged polysilicon formation. We disagree.
It is true that Tatsumi is suggesting that a thickness of 30 nm is about the
smallest that can be achieved by his invention, and claim 1 calls for a “maximum”
thickness of “less than about 30 nm.” However, since the instant claim calls for a
“maximum thickness of less than about 30 nm” and the reference discloses a situation
where 30 nm is “possible,” the prior art does teach a thickness within the range claimed.
For example, the claimed “maximum thickness of less than about 30 nm” might include
5
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 Next
Last modified: November 3, 2007