Patent ID: 7723700
Filing Date: 2010-05-25
Classification: C23C,H01J,Y10T

Abstract:
1. A vapor delivery system for delivering a controlled flow of vapor sublimated from a solid material to a vacuum chamber, comprising the combination of a heated vaporizer for the solid material operable at sub atmospheric pressure and a vapor delivery passage from the vaporizer to the vacuum chamber, the vapor delivery passage including a throttle valve followed by a vapor conduit a pressure gauge that is responsive to sub atmospheric pressure being located between the throttle valve and the vapor conduit, a closed loop temperature control system for maintaining the surfaces of the vapor delivery passage that are exposed to the sublimed vapor, including such surfaces of the throttle valve, the pressure gauge and the vapor conduit at a temperature above the condensation temperature of the solid material, and a closed-loop pressure control system to vary the conductance of the throttle valve to control the sub atmospheric pressure of the vapor downstream of the throttle valve in response to the output of the pressure gauge, so that the flow of vapor to the vacuum chamber is a function of the pressure of the vapor in the region of the passage between the throttling valve and the vapor conduit.