Patent ID: 7566422
Filing Date: 2009-07-28
Classification: G05D

Abstract:
1. An exposure apparatus for exposing a substrate to light, the apparatus comprising: a vacuum container in which the substrate is exposed to light; an exhaust gas line, connected to the vacuum container, for exhausting a gas from the vacuum container; a first vacuum pump connected to the exhaust gas line and configured to exhaust a gas from the vacuum container via the exhaust gas line; a static pressure bearing contained in the vacuum container; a suction chuck contained in the vacuum container and configured to hold a substrate; a second vacuum pump configured to generate vacuum by which the substrate is held to the suction chuck; a first tank connected to the first vacuum pump and configured to store helium gas at a first pressure; a first gas supply line for supplying helium gas from the first tank into the vacuum container; a second tank connected to the first vacuum pump and configured to store helium gas at a second pressure higher than the first pressure; a second gas supply line for supplying helium gas from the second tank to the static pressure bearing; a pipe connecting the first tank and the second tank; a pressure sensor configured to measure a pressure in the first tank; and a control valve provided on the pipe and configured to be opened to supply helium gas from the second tank to the first tank if the pressure measured by the pressure sensor is below the first pressure.