FLOW BALANCING IN GAS DISTRIBUTION NETWORKS

摘要

Flow distribution networks that supply process gas to two or more stations in a multi-station deposition chamber. Each flow distribution network includes an inlet and flow distribution lines for carrying process gas to the stations. The flow distribution lines include a branch point downstream from the inlet and two or more branches downstream from the branch point. Each branch supplies a station. The flow distribution network also includes highly variable flow elements in each branch. Restrictive components are placed downstream from the variable control elements in each branch. These restrictive components are nominally identical and designed to shift the bulk of the pressure drop away from the variable flow components to improve flow balancing while not unduly increasing inlet pressure. In some cases, the load shifting allows the more variable flow components to operate in the unchoked flow regime.

主权项

1. A flow distribution network for supplying a process gas to two or more destinations, the flow distribution network comprising:
an inlet for receiving the process gas; a network of flow distribution lines for carrying the process gas comprising a branch point downstream from the inlet and two or more branches downstream from the branch point, wherein each branch has an outlet for supplying process gas to a corresponding destination; a variable flow element in each branch having a Cv value that varies by at least about 2% from element to element across the branches; and a restrictive component downstream from the variable flow element in each branch, wherein the restrictive components are nominally identical, wherein the flow of the process gas produces a system pressure drop, from the inlet to the outlets, across the flow distribution network is at least as great as the pressure at the outlets.