AVS 45th International Symposium
    Manufacturing Science and Technology Group Monday Sessions
       Session MS-MoA

Paper MS-MoA7
Precise Control of Gas Ratio in Process Chamber

Monday, November 2, 1998, 4:00 pm, Room 317

Session: Contamination Free Manufacturing
Presenter: Y. Shirai, Tohoku University, Japan
Authors: Y. Shirai, Tohoku University, Japan
O. Nakamura, Tohoku University, Japan
N. Ikeda, Fujikin Inc., Japan
R. Dohi, Fujikin Inc., Japan
T. Ohmi, Tohoku University, Japan
Correspondent: Click to Email
In 300mm wafer generation, many kinds of single wafer processing will be necessary to establish higher process uniformity on a wafer. For achieving low cost production, it is necessary high-rate processing such as wafer/min including load-unload time. Process gas distribution system is one of the most critical issues for process uniformity and high-rate processing. Especially, high quality and uniformity of film formation process strongly depends on initial gas distribution in a process chamber. We have developed advanced integrated gas system and studied process gas ratio in process chamber using FT-IR method. We have prepared two types of integrated gas distribution system. One is the conventional system consists of MFC and air operate valve, the other is the advanced system consists of new pressure flow controller with electric valve. This new pressure flow controller built on the principle that the flow rate is directly proportional to the upstream pressure if the upstream pressure is more than two times of downstream pressure. We have introduced three kinds of process gases into a process chamber. The conventional system shows over shoot phenomena. The process gas concentration increase more than two times of the steady state. In addition, it takes more than 20 seconds to be steady state of gas ratio and chamber pressure after the valve operation. On the other hand, the advanced system does not show over shoot phenomena. The steady state of gas ratio and chamber pressure can be obtained within 2 seconds after the valve operation.