Method of manufacturing a shallow trench isolation structure
AssigneeOki Electric Industry Co., Ltd.
InventorTaikan Iinuma
Life of this patent
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Abstract
A semiconductor device is improved in reliability by suppressing the electric-field concentration at a top edge of a trench or the leak current at a bottom edge thereof. A first thermal oxide film is formed by carrying out low-temperature wet oxidation at a silicon substrate heating temperature of approximately 950° C., extending from over a bottom surface of the trench formed in a main surface of a silicon substrate to an intermediate point on a sidewall of the trench. Thereafter, a second thermal oxide film is formed by carrying out high-temperature dry oxidation at a silicon substrate heating temperature of approximately 1100° C., extending from the intermediate point to over the main surface of the silicon substrate outside the trench.
Claims15
A method for manufacturing a semiconductor device comprising:
- a step of forming a groove for forming a device isolation part extending from a main surface of a semiconductor substrate to an intermediate depth of the semiconductor substrate;
- a step of forming by wet oxidation a first thermal oxide film extending from over a bottom surface of the groove to an intermediate point on a sidewall of the groove, the intermediate point being at a depth within a range of 100 nm to 200 nm from the main surface of the semiconductor substrate;
- and
- a step of forming by dry oxidation a second thermal oxide film extending from the intermediate point on the sidewall of the groove to over the main surface of the semiconductor substrate.
A method of manufacturing a semiconductor device comprising:
- forming a groove in a surface of a semiconductor substrate;
- forming a first thermal oxide on a bottom of the groove and extending up to an intermediate point on a sidewall of the groove, by wet oxidation;
- forming a second thermal oxide on the surface of the semiconductor substrate and extending down to the intermediate point on the sidewall of the groove, by dry oxidation;
- and
- forming an insulating film to entirely bury the groove, after said forming a first thermal oxide and said forming a second thermal oxide.
Dependencies are inferred from the claim text.