Appeal No. 2001-1512 Page 2
Application No. 09/273,541
BACKGROUND
Appellant’s invention is directed to a method of assessing
substrate temperature controllability in a substrate processing
apparatus. An inert cooling gas such as helium (He) is supplied
to a gap between the substrate and an electrostatic chucking
stage, which functions as a heat transfer gas and maintains the
substrate temperature constant during processing (specification,
page 2). In contrast with the conventional method of controlling
the cooling gas pressure by opening and closing a bypass valve,
Appellant’s invention controls the pressure by a flow rate based
on the difference between a measured pressure and a set value
(specification, page 7). The flow rate value corresponds to the
extend the cooling gas leaks out from the gap between the
substrate and the chucking stage (specification, page 13) and
indicates unsatisfactory state of chucking when the amount of
leakage is high (specification, page 14).
The only independent claim is reproduced as follows:
4. A method of assessing a substrate condition of a
substrate, comprising the steps of:
delivering a heat transfer gas to a control device
including an exhaust valve and a pressure control valve;
supplying a set pressure value to the pressure control
valve;
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