ORIFICE SET INSTALLED AT BACKSIDE GAS LINE

摘要

PURPOSE: An orifice set installed at a backside gas line is provided to increase the distance of passage of the backside gas through the orifice set by differentiating the number and arrangement of the holes formed at the orifice. CONSTITUTION: The orifice set has the first orifice(150) and the second orifice alternately deposited. The first orifice has a body(152), and a wall(154) surrounding the periphery of the body(152) with a predetermined height. Four holes(156) are equidistantly formed at the periphery of the body(152). As with the first orifice(150), the second orifice has a body, and a wall surrounding the periphery of the body with a predetermined height. A hole is formed only at the center of the body. The holes(156) of the first orifice(150) and the hole of the second orifice are not overlapped with each other.