Semiconductor device and process for producing the same

• US 20030181020A1
• Filed: 03/21/2003
• Published: 09/25/2003
• Est. Priority Date: 02/18/1997
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Technology Corporation (Renesas Electronics Corporation)
• Inventors: Suzuki, Norio, Yoshida, Yasuko, Miura, Hideo, Kobayashi, Masamichi, Ikeda, Shuji, Ishitsuka, Norio, Yamamoto, Hirohiko, Shimizu, Hirofumi, Matsuda, Yasushi, Nozoe, Toshio, Horibe, Shinichi, Fukuda, Kazushi, Takamatsu, Akira
• Granted Patent: US 6,881,646 B2
• Time in Patent Office: Days
• US Class Current: 438/424
• CPC Class Codes: H01L 21/76232 of trenches having a shape other than rectangular or V-shape, e.g. rounded corners, oblique or rounded trench walls H01L21/76229 takes precedence
• CPC Class Codes: H01L 21/76235 trench shape altered by a local oxidation of silicon process step, e.g. trench corner rounding by LOCOS
• CPC Class Codes: H01L 29/78 with field effect produced by an insulated gate H01L29/7725, H01L29/775, H01L29/778 take precedence

Abstract

A process of producing a semiconductor device having a highly reliable groove isolation structure with a desired radius of curvature formed at the groove upper edge and without formation of any step. The device is produced by reducing the stress generation around the groove upper edge of an element isolation groove on a semiconductor substrate, thereby optimizing the shape of an element isolation groove and making the device finer and improving the device electric characteristics.

Claims

1. A process for producing a semiconductor device, which comprises the following steps:

a step of forming a first oxide film on a circuit forming side of a semiconductor substrate by a first oxidizing process of the semiconductor substrate,

a step of forming an anti-oxidation film on the first oxide film,

a step of forming a photoresist film on the anti-oxidation film,

a step of removing a portion of the photoresist film,

a step of removing portions of the anti-oxidation film and the first oxide film,

a step of trenching a groove on the semiconductor substrate in a portion of the semiconductor substrate from which the first oxide film is removed,

a step of removing another portion of the photoresist film on the anti-oxidation film,

a step of forming a space by recessing the first oxide film to an extent of 5 nm to 40 nm from an element isolation region,

a step of forming a second silicon oxide film in the space and on an inside wall of the groove by a second oxidizing process of the semiconductor substrate,

a step of embedding an element isolation film on the second oxide film in the groove,

a step of removing the anti-oxidation film and the first oxide film on the semiconductor substrate, and

a step of forming a gate dielectric film and a gate electrode on a portion of the semiconductor substrate from which the first oxide film is removed.

2. A process according to claim 1, wherein the antioxidation film is a silicon nitride film.

3. A process for producing a semiconductor device, which comprises the following steps:

a step of forming a first oxide film on a semiconductor substrate by a first oxidizing process of the semiconductor substrate,

a step of forming a silicon nitride film on the first oxide film,

a step of forming a photoresist film on an anti-oxidation film,

a step of removing a portion of the photoresist film,

a step of removing the anti-oxidation film and the first oxide film at the removed portion of the photoresist film,

a step of trenching a groove on the semiconductor substrate in an element isolation region in a portion of the semiconductor substrate from which the first oxide film is removed,

a step of removing another portion of the photoresist film on the silicon nitride film,

a step of forming a recessed space under the silicon nitride film by etching the first oxide film from the region where the groove is formed,

a step of forming a second oxide film in the recessed space by thermally oxidizing the semiconductor substrate to a degree not greater than an amount of oxidation that develops upward warping deformation of the silicon nitride film,

a step of embedding a third oxide film in the groove, a step of removing the silicon nitride film and the first oxide film on the semiconductor substrate, and a step of forming a gate dielectric film and a gate electrode on the semiconductor substrate.

4. A process for producing a semiconductor device, which comprises the following steps:

a step of forming a pad oxide film on a circuit forming side of a semiconductor substrate,

a step of forming an anti-oxidation film on the pad oxide film,

a step of forming a photoresist film on the anti-oxidation film,

a step of removing a portion of the photoresist film,

a step of removing portions of the anti-oxidation film and the pad oxide film,

a step of trenching a groove on the semiconductor substrate in a portion of the semiconductor substrate from which the pad oxide film has been removed while masking an element region,

a step of removing another portion of the photoresist film on the anti-oxidation film,

a step of forming a space to an extent of 5 to 40 nm on the semiconductor surface around the groove by etching the pad oxide film from the side wall of the groove,

a step of forming a second silicon oxide film in the recessed space until the recessed space and a surface in the groove are fully covered by the second oxide film,

a step of embedding an element isolation film in the groove having the second oxide film,

a step of removing the anti-oxidation film and the pad oxide film on the semiconductor substrate,

a step of forming a gate dielectric film on the surface of the semiconductor substrate in the element isolation region, and

a step of forming a gate electrode on the gate dielectric film.