Appeal No. 1998-2342 Page 5
Application No. 08/505,739
accomplish the movement. The apparatus also contains a sensor connected to the target and a
controller having a programmed processor connected to the output of the sensor. The program must
accomplish two tasks. It must determine spacing as a function of target consumption and it must
generate an output signal. The function is one which will change the spacing so as to produce a film of a
given film thickness uniformity across the surface of a substrate. We interpret the phrase “a given film
thickness uniformity” similarly to “maintaining thickness uniformity” above. Therefore, the program must
be capable of producing films with a degree of thickness uniformity on the order of +/- 5 percent. As
the claim is not limited to a semiconductor wafer manufacturing apparatus, levels above +/- 5 percent
may be encompassed.
Claim 20 is drawn to a sputtering method including a step of deriving target-to-substrate
spacing as a function of target erosion. The claim requires that this function be derived through
experimentation. The experiments involve measuring film thickness deviations over the surface of the
sputtered film at different sputtering distances. After the formula is derived from the thickness deviation
measurements, the sputtering process is conducted while changing the target-to-substrate spacing using
the empirically derived function.
With these claim limitations in mind, we turn to the prior art rejections.
Claims 1, 14, and 20 are subjected to two rejections. The subject matter of these claims stand
rejected as anticipated over Tepman and as obvious over Tepman and Sasaki in view of
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