Method and apparatus for controlling the thickness of a gate oxide in a semiconductor manufacturing process
AssigneeAdvanced Micro Devices, Inc.
InventorDonald L. Wollesen
Life of this patent
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Abstract
A method and apparatus for controlling the growth of an oxide, such as a gate oxide, in a semiconductor device manufacturing process takes into consideration the ambient atmospheric pressure in order to reduce the variance in gate oxide thicknesses between wafer lots. The pressure in the oxide diffusion tube is maintained at a constant pressure near the ambient atmospheric pressure during the oxide diffusion process. Alternatively, the furnace time is changed from lot to lot as a function of changes in the ambient atmospheric pressure in order to maintain the gate oxide thickness at a constant value between wafer lots.
Claims8
A method of controlling growth of an oxide in a semiconductor device manufacturing process, comprising the steps of:
- positioning at least one object on which oxide is to be grown within an oxide diffusion tube;
- maintaining a constant pressure of gas within the oxide diffusion tube, the pressure being approximately ambient atmospheric pressure, regardless of changes to ambient pressure outside the oxide diffusion tube;
- and
- growing the oxide on the object until a thickness of the oxide is achieved;
- wherein the step of maintaining a constant pressure includes determining a lowest atmospheric pressure as a function of the altitude of the oxide diffusion tube and a lowest expected barometric pressure at that altitude, and producing a negative pressure relative to atmospheric pressure.
A method of controlling growth of an oxide in a semiconductor device manufacturing process, comprising the steps of:
- positioning at least one object on which oxide is to be grown within an oxide diffusion tube;
- maintaining a constant pressure of gas within the oxide diffusion tube, the pressure being approximately ambient atmospheric pressure;
- and
- growing the oxide on the object until a thickness of the oxide is achieved;
- wherein the step of maintaining a constant pressure includes determining a lowest atmospheric pressure as a function of the altitude of the oxide diffusion tube and a lowest expected barometric pressure at that altitude, and producing a negative pressure relative to atmospheric pressure.
Dependencies are inferred from the claim text.