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US 6,602,799 B2Granted
Method of forming a uniform ultra-thin gate oxide layer
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChi-Chun Chen, Wen Chang, Michael Chang, Shih-Chang Chen
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Abstract
A method of forming a highly uniform ultra-thin insulating gate oxide layer on a silicon wafer is presented where an oxide layer non-uniformity introduced at a processing temperature is compensated during a cooling step during which oxygen is added to give additional oxide layer growth thereby producing a substantially uniform oxide layer.
Claims19
A method of forming a uniform oxide layer on at least one substrate comprising the steps of:
- heating at least one substrate to a process temperature;
- passing a water vapor and oxygen gas mixture over the at least one substrate at the process temperature to form an oxide layer on the at least one substrate;
- annealing the oxide layer at an annealing temperature;
- cooling the oxide layer to a pre-determined lower temperature;
- and,
- adding an oxygen containing ambient comprising a concentration of oxygen within a range of about 0.01 percent to about 2% percent by volume during at least a portion of the cooling step to improve the oxide layer thickness uniformity.
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A method of forming a uniform ultra-thin oxide layer on at least one semiconductor process wafer comprising the steps of:
- providing at least one semiconductor process wafer within a furnace;
- heating the at least one semiconductor process wafer to a process temperature;
- passing a water vapor and oxygen gas mixture over the at least one semiconductor process wafer at the process temperature to form an oxide layer on the at least one semiconductor process wafer;
- annealing the oxide layer to form an oxide layer temperature profile;
- changing the oxide layer temperature profile such that the oxide layer temperature profile is substantially reversed whereby relatively lower temperature portions of the oxide layer become relatively higher temperature portions of the oxide layer and relatively higher temperature portions of the oxide layer become relatively lower temperature portions of the oxide layer;
- and,
- adding an oxygen containing ambient for a period of time whereby additional oxide growth takes place preferentially on the relatively higher temperature portions of the oxide layer such that the oxide layer thickness uniformity is improved.
4 more elements
Dependencies are inferred from the claim text.