Patent ID: 7108751

Claim:
A gas injection system in a plasma processing device comprising: a gas injection assembly body configured to receive a process gas from at least one mass flow controller; a consumable gas inject plate coupled to said gas injection assembly body, said consumable gas inject plate comprising at least one orifice to distribute said process gas to said plasma processing device; a pressure sensor coupled to said gas injection assembly body and configured to measure a gas injection pressure within a gas injection plenum formed by said gas injection assembly body and said consumable gas inject plate; and a controller coupled to said pressure sensor and configured to determine a degree of consumption of said consumable gas inject plate from a change in said gas injection pressure, wherein said controller determines a response time for the change in said gas injection pressure and compares the response time with a first time delay in a first time trace corresponding to when said at least one orifice of said consumable gas inject plate corresponds to a non-eroded state.