# US 9,437,637 B2 · Semiconductor device manufacturing method and resist pattern forming method

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- Number: US 9,437,637 B2
- Document ID: US9437637B2
- Status: Granted
- Kind: B2
- Application number: 14/681,350
- Filed: 2015-04-08
- Published: 2015-10-22
- Granted: 2016-09-06
- Earliest claimed: 2014-04-16
- Assignees: Canon Kabushiki Kaisha
- Applicants: Canon Kabushiki Kaisha
- Inventors: Atsushi Kanome; Nobutaka Ukigaya; Koji Hara; Satoshi Yoshizaki; Masahiko Kondo
- Web page: https://patentgrep.com/patent/US9437637B2

## CPC

- H10F 39/807: {Pixel isolation structures}
- G03F 7/0035: {Multiple processes, e.g. applying a further resist layer on an already in a previously step, processed pattern or textured surface}
- G03F 7/40: Treatment after imagewise removal, e.g. baking
- H10F 39/014: {of CMOS image sensors}
- H10F 39/18: Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
- H10F 39/8033: {Photosensitive area}
- H10P 30/204: {into Group IV semiconductors}
- H10P 30/21: {of electrically active species}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method for manufacturing a semiconductor device comprising, forming a first photoresist pattern by exposing and then developing a first photoresist film formed on a substrate, irradiating the first photoresist pattern with UV light to cure its surface, forming a second photoresist film so as to cover the substrate and the first photoresist pattern, forming a second photoresist pattern and performing ion implantation in the substrate using the second photoresist pattern. The second photoresist pattern is not subjected to UV irradiation after the second photoresist film has been developed and before the ion implantation is performed, or is irradiated with the UV light, after the second photoresist film has been developed and before the ion implantation is performed, under a reduced condition relative to that for the first photoresist pattern.

## Claims

### Claim 1

A method for manufacturing a semiconductor device comprising:
a first step of forming a first photoresist film on a substrate;
a second step of forming a first photoresist pattern by exposing and then developing the first photoresist film;
a third step of irradiating the first photoresist pattern with ultraviolet light to cure a surface of the first photoresist pattern;
a fourth step of forming a second photoresist film so as to cover the substrate and the first photoresist pattern;
a fifth step of forming a second photoresist pattern at least a part of which is provided on the first photoresist pattern by exposing and then developing the second photoresist film; and
a sixth step of performing ion implantation in the substrate using the second photoresist pattern,
wherein the second photoresist pattern is:
(i) not subjected to ultraviolet irradiation after the second photoresist film has been developed and before the ion implantation is performed, or
(ii) irradiated with the ultraviolet light, after the second photoresist film has been developed and before the ion implantation is performed, under a condition that at least one of an ultraviolet light irradiation amount, an ultraviolet light irradiation time, and an atmospheric temperature at the time of ultraviolet irradiation is reduced relative to that in the third step, and
wherein, in the fifth step, a mask having an opening a diameter of which is smaller than that of an opening of a mask that is used in the second step is used.

### Claim 2

A method for manufacturing a semiconductor device comprising:
a first step of forming a first photoresist film on a substrate;
a second step of forming a first photoresist pattern by exposing and then developing the first photoresist film;
a third step of irradiating the first photoresist pattern with ultraviolet light to cure a surface of the first photoresist pattern;
a fourth step of forming a second photoresist film so as to cover the substrate and the first photoresist pattern;
a fifth step of forming a second photoresist pattern at least a part of which is provided on the first photoresist pattern by exposing and then developing the second photoresist film; and
a sixth step of performing ion implantation in the substrate using the second photoresist pattern,
wherein the second photoresist pattern is:
(i) not subjected to ultraviolet irradiation after the second photoresist film has been developed and before the ion implantation is performed, or
(ii) irradiated with the ultraviolet light, after the second photoresist film has been developed and before the ion implantation is performed, under a condition that at least one of an ultraviolet light irradiation amount, an ultraviolet light irradiation time, and an atmospheric temperature at the time of ultraviolet irradiation is reduced relative to that in the third step,
wherein an opening that passes through the first photoresist pattern and the second photoresist pattern is formed in the second photoresist pattern in the first to fifth steps, and
wherein a side face of the opening is formed only by the second photoresist pattern, among the first photoresist pattern and the second photoresist pattern.

### Claim 3

A method for manufacturing a semiconductor device comprising:
a first step of forming a first photoresist film on a substrate;
a second step of forming a first photoresist pattern by exposing and then developing the first photoresist film;
a third step of irradiating the first photoresist pattern with ultraviolet light to cure a surface of the first photoresist pattern;
a fourth step of forming a second photoresist film so as to cover the substrate and the first photoresist pattern;
a fifth step of forming a second photoresist pattern at least a part of which is provided on the first photoresist pattern by exposing and then developing the second photoresist film; and
a sixth step of performing ion implantation in the substrate using the second photoresist pattern,
wherein the second photoresist pattern is:
(i) not subjected to ultraviolet irradiation after the second photoresist film has been developed and before the ion implantation is performed, or
(ii) irradiated with the ultraviolet light, after the second photoresist film has been developed and before the ion implantation is performed, under a condition that at least one of an ultraviolet light irradiation amount, an ultraviolet light irradiation time, and an atmospheric temperature at the time of ultraviolet irradiation is reduced relative to that in the third step,
wherein, in the sixth step, a photoelectric conversion region is formed in an active region surrounded by an element isolation portion formed in the substrate, and
wherein the second photoresist pattern has, in the active region, an end that forms a part of a side face of an opening for forming the photoelectric conversion region.

### Claim 4 (depends on 3)

The method according to claim 3,
wherein, in the sixth step, a plurality of photoelectric conversion regions are formed in the same active region surrounded by the element isolation portion, and
wherein the second photoresist pattern has, in the active region, ends that form parts of side faces of a plurality of openings for forming the plurality of photoelectric conversion regions in the same active region.

### Claim 5 (depends on 4)

The method according to claim 4, wherein the second photoresist pattern includes parts that include, on face and rear sections thereof, ends forming a part of the respective side faces of the plurality of openings.

### Claim 6 (depends on 3)

The method according to claim 3, wherein the end is formed perpendicular to the substrate.

### Claim 7 (depends on 3)

The method according to claim 3, wherein the first photoresist pattern is used for forming a gate electrode of a transfer MOS transistor for transferring an electrical charge from the photoelectric conversion region.

### Claim 8

A method for forming a resist pattern comprising:
a first step of forming a first photoresist film on a substrate;
a second step of forming a first photoresist pattern by exposing and then developing the first photoresist film;
a third step of irradiating the first photoresist pattern with ultraviolet light to cure a surface of the first photoresist pattern;
a fourth step of forming a second photoresist film so as to cover the substrate and the first photoresist pattern;
a fifth step of forming a second photoresist pattern at least a part of which is provided on the first photoresist pattern by exposing and then developing the second photoresist film; and
a sixth step of irradiating the second photoresist pattern with ultraviolet light to cure a surface of the second photoresist pattern,
wherein, in the sixth step, at least one of an ultraviolet light irradiation amount, an ultraviolet light irradiation time, and an atmospheric temperature at the time of ultraviolet irradiation is reduced relative to that in the third step.

### Claim 9

A method for forming a resist pattern comprising:
a first step of forming a first photoresist film on a substrate;
a second step of forming a first photoresist pattern by exposing and then developing the first photoresist film;
a third step of irradiating the first photoresist pattern with ultraviolet light to cure a surface of the first photoresist pattern;
a fourth step of forming a second photoresist film so as to cover the substrate and the first photoresist pattern; and
a fifth step of forming a second photoresist pattern at least a part of which is provided on the first photoresist pattern by exposing and then developing the second photoresist film,
wherein, in the fifth step, a mask having an opening a diameter of which is smaller than that of an opening of a mask that is used in the second step is used.

### Claim 10 (depends on 9)

The method according to claim 9,
wherein an opening that passes through the first photoresist pattern and the second photoresist pattern is formed in the second photoresist pattern in the first to fifth steps, and
wherein a side face of the opening is formed by the first photoresist pattern and the second photoresist pattern.