Patent ID: 6029717
Filing Date: 2000-02-29
Classification: B01J,B01L,B67D,C23C,F17C,G01F,G05D,H01J

Abstract:
A canister for direct liquid injection of high purity chemicals to semiconductor fabrication process tools, comprising:a cylindrical stainless steel container comprising an inlet and an outlet, wherein the container is formed by welding stainless steel electropolished end caps to seamless stainless steel electropolished tubing whereby the end caps form a top and bottom of the container, wherein the inlet and outlet are disposed in the top of the container, wherein a draw tube is in communication with the outlet and the draw tube extends to near the bottom of the container, wherein the container has a height-to-diameter ratio of between about 3:1 to about 6:1 and wherein a level sensor is disposed in the container and has a refill trigger point and a cable for communicating a refill signal from the level sensor to a refill indicator circuit when the volume of the high purity chemical is less than about 40% of the container volume.