Gas flow control system with interlock
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChih-Pen Yen, Jeng-Yann Tsay, Jeng-Chiang Chuang, Cheng-Fang Lin, Yung-Mao Hsu
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Abstract
A system for controlling the flow of gases into a reaction chamber used in processing semiconductor devices includes a safety interlock feature that prevents inadvertent mixing of incompatible, reactive gases. The interlock feature is implemented in an interlock control circuit which operates a valve system for individually controlling the flow of separate gases into the chamber. The interlock circuit includes a series of relay switches and timers arranged to create a time delay between the initiation of flow of gases from separate sources into the chamber.
Claims20
A system for controlling the introduction of chemically reactive gases into a processing chamber used to manufacture semiconductor devices, comprising:
- a first valve system for controlling the flow of a first reactive gas into said chamber;
- a second valve system for controlling the flow of a second reactive gas into said chamber;
- and,
- a cross interlock circuit coupled with and controlling said first and second valve systems for preventing simultaneous flow of said first and second gases into said chamber.
A system for controlling the introduction of chemically reactive gases into a processing chamber used to manufacture semiconductor devices, comprising:
- a first valve system for controlling the flow of a first reactive gas into said chamber;
- a second valve system for controlling the flow of a second reactive gas into said chamber;
- and
- a cross interlock circuit coupled with and controlling said first and second valve systems for preventing simultaneous flow of said first and second gases into said chamber, said interlock circuit including
- a) a first actuatable relay circuit for controlling the operation of said first valve system,
- b) a second actuatable relay circuit for controlling the operation of said second valve system,
- c) a first time delay controller for delaying the operation of said first valve system for a preselected period of time after said first relay circuit has been actuated, whereby to assure that the flow of said first gas into said chamber has stopped before said second gas begins to flow into said chamber, and,
- d) a second time delay controller for delaying the operation of said second valve system for a preselected period of time after said second relay circuit has been actuated,
- whereby to assure that the flow of said second gas into said chamber has stopped before said first gas begins to flow into said chamber, said first and second time delay controllers cooperating to prevent undesired mixing of said first and second gases.
A method for controlling the introduction of chemically reactive gases into a processing chamber used to manufacture semiconductor devices, comprising the steps of:
- (A) producing a first control signal for opening a first valve system allowing the flow of a first reactive gas into said chamber;
- (B) producing a second control signal for opening a second valve system allowing the flow of a second reactive gas into said chamber;
- (C) delaying the opening of said first valve system for a first predetermined length of time after said first signal is produced in step (A);
- (D) delaying the opening of said second valve system for a second predetermined length of time after said second signal is produced in step (B),
- the delays of steps (C) and (D), preventing potentially hazardous mixing of said first and second gases.
Dependencies are inferred from the claim text.