| 摘要 |
PURPOSE:To contrive the improvement of workability and quality, by providing a conductance variable device between a reserve chamber and pressure reduction device of electron exposure. CONSTITUTION:The conductance variable device 4 provided between the reserve chamber 1 and vacuum pump 3 has an exhaust hole with diameter 0.3-0.5mm. on a sluice valve. Exhaust through the hole 5 at the exhaust start reduces the exhaust speed with the pressure drop in the chamber 1 slowed down for extremely less influence by adiabatic expansion owing to high conductance. After reaching some pressure value, the variable device 4 is displaced to make the pump 3 display full exhaustion capacity. Then, the reserve chamber 1 can be provided with a fixed vacuum degree relatively rapidly to give the gas less influence by adiabatic expansion with very small decrease of temperature. The use of an exhaust speed variable type for the pump 3 is likewise available. In this constitution, a cassette 2 with an exposed matter built-in settled in the reserve chamber 1 recovers to a fixed temperature in a short time for the acceleration of work with no strain by the temperature recovery during exposure. |
