# US 12,183,809 B2 · Manufacturing method of semiconductor device

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- Number: US 12,183,809 B2
- Document ID: US12183809B2
- Status: Granted
- Kind: B2
- Application number: 17/673,819
- Filed: 2022-02-17
- Published: 2023-07-20
- Granted: 2024-12-31
- Earliest claimed: 2022-01-20
- Assignees: United Microelectronics Corp.
- Applicants: United Microelectronics Corp.
- Inventors: Wei-Lun Huang; Chia-Ling Wang; Chia-Wen Lu; Ta-Wei Chiu; Ping-Hung Chiang
- Web page: https://patentgrep.com/patent/US12183809B2

## CPC

- H10D 30/0289: {using recessing of the gate electrodes, e.g. to form trench gate electrodes}
- H10D 30/608: {having non-planar bodies, e.g. having recessed gate electrodes}
- H10D 62/116: {adjoining the input or output regions of field-effect devices, e.g. adjoining source or drain regions}
- H10D 64/01: Manufacture or treatment
- H10D 64/027: {by etching at gate locations}
- H10D 84/0144: {Manufacturing their gate insulating layers}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 64/514: {characterised by the insulating layers}
- H10D 84/013: {Manufacturing their source or drain regions, e.g. silicided source or drain regions}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A manufacturing method of a semiconductor device includes the following steps. A first recess and a second recess are formed in a first region and a second region of a semiconductor substrate, respectively. A bottom surface of the first recess is lower than a bottom surface of the second recess in a vertical direction. A first gate oxide layer and a second gate oxide layer are formed concurrently. At least a portion of the first gate oxide layer is formed in the first recess, and at least a portion of the second gate oxide layer is formed in the second recess. A removing process is performed for removing a part of the second gate oxide layer. A thickness of the second gate oxide layer is less than a thickness of the first gate oxide layer after the removing process.

## Claims

### Claim 1

A manufacturing method of a semiconductor device, comprising:
forming a first recess in a first region of a semiconductor substrate;
forming a second recess in a second region of the semiconductor substrate, wherein a bottom surface of the first recess is lower than a bottom surface of the second recess in a vertical direction, and the first recess and the second recess are formed concurrently;
forming a first gate oxide layer and a second gate oxide layer concurrently, wherein at least a portion of the first gate oxide layer is formed in the first recess, and at least a portion of the second gate oxide layer is formed in the second recess;
performing a removing process for removing a part of the second gate oxide layer, wherein a thickness of the second gate oxide layer is less than a thickness of the first gate oxide layer after the removing process;
forming a pad oxide layer on the semiconductor substrate before the first recess and the second recess are formed, wherein a first portion of the pad oxide layer is formed on the first region of the semiconductor substrate, a second portion of the pad oxide layer is formed on the second region of the semiconductor substrate, and a third portion of the pad oxide layer is formed on a third region of the semiconductor substrate; and
removing the third portion of the pad oxide layer after the first gate oxide layer and the second gate oxide layer are formed and before the removing process.

### Claim 2 (depends on 1)

The manufacturing method of the semiconductor device according to claim 1, wherein a bottom surface of the first gate oxide layer is lower than a bottom surface of the second gate oxide layer in the vertical direction.

### Claim 3 (depends on 1)

The manufacturing method of the semiconductor device according to claim 1, wherein a top surface of the second gate oxide layer is higher than a top surface of the first gate oxide layer in the vertical direction before the removing process.

### Claim 4 (depends on 1)

The manufacturing method of the semiconductor device according to claim 1, wherein the first portion and the second portion of the pad oxide layer are removed by the removing process.

### Claim 5 (depends on 1)

The manufacturing method of the semiconductor device according to claim 1, further comprising:
forming a third gate oxide layer on the third region of the semiconductor substrate after the third portion of the pad oxide layer is removed and before the removing process.

### Claim 6 (depends on 5)

The manufacturing method of the semiconductor device according to claim 5, wherein a thickness of the third gate oxide layer is less than the thickness of the second gate oxide layer before and after the removing process.

### Claim 7 (depends on 5)

The manufacturing method of the semiconductor device according to claim 5, wherein a bottom surface of the third gate oxide layer is higher than a bottom surface of the first gate oxide layer and a bottom surface of the second gate oxide layer in the vertical direction.

### Claim 8 (depends on 5)

The manufacturing method of the semiconductor device according to claim 5, further comprising:
forming a patterned mask layer on the semiconductor substrate before the removing process, wherein the first gate oxide layer and the third gate oxide layer are covered by the patterned mask layer during the removing process.

### Claim 9 (depends on 1)

The manufacturing method of the semiconductor device according to claim 1, further comprising:
forming a third recess in first region of the semiconductor substrate; and
forming a fourth recess in the third region of the semiconductor substrate, wherein the third recess and the fourth recess are formed concurrently before the pad oxide layer is formed, the third portion of the pad oxide layer is formed in the fourth recess, and the first portion of the pad oxide layer is partly formed in the third recess and partly formed outside the third recess.

### Claim 10 (depends on 9)

The manufacturing method of the semiconductor device according to claim 9, wherein the first portion of the pad oxide layer located in the third recess is lower than the second portion of the pad oxide layer in the vertical direction.

### Claim 11 (depends on 9)

The manufacturing method of the semiconductor device according to claim 9, wherein the first portion of the pad oxide layer located in the third recess is removed by a process of forming the first recess, and the second portion of the pad oxide layer is removed by a process of forming the second recess.

### Claim 12 (depends on 1)

The manufacturing method of the semiconductor device according to claim 1, further comprising:
forming a first isolation structure in the first region of the semiconductor substrate; and
forming a second isolation structure in the second region of the semiconductor substrate, wherein the first isolation structure comprises a protruding part extending downwards, and the protruding part is lower than a bottom surface of the second isolation structure in the vertical direction.

### Claim 13 (depends on 12)

The manufacturing method of the semiconductor device according to claim 12, wherein the first isolation structure is directly connected with the first gate oxide layer, and the second isolation structure is directly connected with the second gate oxide layer.

### Claim 14 (depends on 12)

The manufacturing method of the semiconductor device according to claim 12, wherein a part of the first isolation structure and a part of the second isolation structure are removed by the removing process.

### Claim 15 (depends on 12)

The manufacturing method of the semiconductor device according to claim 12, further comprising:
forming a patterned mask layer on the semiconductor substrate before the removing process, wherein the first gate oxide layer, a part of the first isolation structure, and a part of the second isolation structure are covered by the patterned mask layer during the removing process.

### Claim 16 (depends on 1)

The manufacturing method of the semiconductor device according to claim 1, wherein a portion of the second gate oxide layer is formed outside the second recess and removed by the removing process.

### Claim 17 (depends on 1)

The manufacturing method of the semiconductor device according to claim 1, wherein the removing process comprises a dry etching step and a wet etching step performed after the dry etching step.