# US 11,443,956 B2 · Method for manufacturing semiconductor device

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- Number: US 11,443,956 B2
- Document ID: US11443956B2
- Status: Granted
- Kind: B2
- Application number: 17/165,199
- Filed: 2021-02-02
- Published: 2021-08-12
- Granted: 2022-09-13
- Earliest claimed: 2020-02-06
- Assignees: Sumitomo Electric Industries, Ltd.
- Applicants: Sumitomo Electric Industries, Ltd.
- Inventors: Tadashi Watanabe
- Web page: https://patentgrep.com/patent/US11443956B2

## CPC

- H10P 50/73: {using masks for insulating materials}
- H10D 30/015: {of FETs having heterojunction interface channels or heterojunction gate electrodes, e.g. HEMT}
- H10D 64/01: Manufacture or treatment
- H10D 64/01324: {characterised by the sectional shape, e.g. T or inverted-T}
- H10D 64/01334: {by defining the insulator using a sidewall spacer mask, a transformation under a mask or a plating at a sidewall}
- H10D 64/111: {Field plates}
- H10D 64/258: {characterised by the relative positions of the source or drain electrodes with respect to the gate electrode}
- H10D 84/0135: {Manufacturing their gate conductors}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10P 76/202: {for lift-off processes}
- H10P 76/2041: {Photolithographic processes}
- H10D 30/475: {having wider bandgap layer formed on top of lower bandgap active layer, e.g. undoped barrier HEMTs such as i-AlGaN/GaN HEMTs}
- H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN}
- H10D 64/411: {for FETs}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method for manufacturing a semiconductor device includes steps of forming a protective film on a semiconductor substrate, forming a resist film on the protective film such that the resist film includes a region where the resist film becomes thicker from a drain electrode to a source electrode, forming a first opening in the resist film by irradiating the resist film in the region with an electron beam and developing the resist film, forming a second opening that exposes an upper surface of the semiconductor substrate by removing the protective film using the resist film in which the first opening is formed as a mask, forming a third opening in the resist film by further developing the resist film after forming the second opening, the third opening being formed by expanding the first opening toward the drain electrode, and forming a gate electrode in the second and the third openings.

## Claims

### Claim 1

A method for manufacturing a semiconductor device having a source electrode, a drain electrode, and a gate electrode provided between the source electrode and the drain electrode, the method comprising steps of:
forming a protective film on a semiconductor substrate;
forming a resist film on the protective film such that the resist film includes a region where the resist film becomes thicker from the drain electrode to the source electrode, the region being provided between the source electrode and the drain electrode;
forming a first opening in the resist film by irradiating the resist film in the region with an electron beam and developing the resist film;
forming a second opening that exposes an upper surface of the semiconductor substrate by removing the protective film using the resist film in which the first opening is formed as a mask;
forming a third opening in the resist film by further developing the resist film after forming the second opening, the third opening being formed by expanding the first opening toward the drain electrode; and
forming the gate electrode in the second opening and the third opening.

### Claim 2 (depends on 1)

The method for manufacturing the semiconductor device according to claim 1, wherein
the step of forming the resist film includes setting thicknesses of the source electrode and the drain electrode to be larger than a thickness of the protective film, and forming the resist film so that the resist film covers the source electrode and the drain electrode to form the region.

### Claim 3 (depends on 2)

The method for manufacturing the semiconductor device according to claim 2, wherein
a distance between the region and the source electrode is shorter than a distance between the region and the drain electrode.

### Claim 4 (depends on 2)

The method for manufacturing the semiconductor device according to claim 2, wherein
in the step of forming the resist film, a thickness of the source electrode is set to be larger than that of the drain electrode.