# US 11,079,682 B1 · Methods for extreme ultraviolet (EUV) resist patterning development

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- Number: US 11,079,682 B1
- Document ID: US11079682B1
- Status: Granted
- Kind: B1
- Application number: 17/097,921
- Filed: 2020-11-13
- Granted: 2021-08-03
- Earliest claimed: 2020-11-13
- Assignees: Tokyo Electron Limited
- Applicants: Tokyo Electron Limited
- Inventors: Yun Han; Peter Ventzek; Alok Ranjan
- Web page: https://patentgrep.com/patent/US11079682B1

## CPC

- G03F 7/0043: {Chalcogenides; Silicon, germanium, arsenic or derivatives thereof; Metals, oxides or alloys thereof (G03F7/0044 takes precedence)}
- G03F 7/70033: {by plasma extreme ultraviolet [EUV] sources}
- G03F 7/2014: {Contact or film exposure of light sensitive plates such as lithographic plates or circuit boards, e.g. in a vacuum frame}
- G03F 7/36: Imagewise removal not covered by groups G03F7/30 - G03F7/34, e.g. using gas streams, using plasma
- G03F 7/38: Treatment before imagewise removal, e.g. prebaking {(G03F7/265 takes precedence)}
- H10P 14/6319: {Formation by plasma treatments, e.g. plasma oxidation of the substrate}
- H10P 14/69392: {the material containing hafnium, e.g. HfO2}
- H10P 50/283: {by chemical means}
- H10P 50/287: {by chemical means}
- H10P 76/2041: {Photolithographic processes}
- H10P 76/4085: {characterised by the processes involved to create the masks}
- H01J 37/32082: {Radio frequency generated discharge (H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence)}
- 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
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

Methods are provided herein for patterning extreme ultraviolet (EUV) (or lower wavelength) photoresists, such metal-oxide photoresists. A patterning layer comprising a metal-oxide photoresist is formed on one or more underlying layers provided on a substrate, and portions of the patterning layer not covered by a mask overlying the patterning layer are exposed to EUV or lower wavelengths light. A cyclic dry process is subsequently performed to remove portions of the patterning layer exposed to the EUV or lower wavelength light (i.e., the exposed portions) and develop the metal-oxide photoresist pattern. The cyclic dry process generally includes a plurality of deposition and etch steps, wherein the deposition step selectively deposits a protective layer onto unexposed portions of the patterning layer by exposing the substrate to a first plasma, and the etch step selectively etches the exposed portions of the patterning layer by exposing the substrate to a second plasma.

## Claims

### Claim 1

A method for patterning a substrate, the method comprising:
forming a patterning layer and one or more underlying layers on the substrate, wherein the patterning layer comprises a metal-oxide photoresist;
performing an extreme ultraviolet (EUV) or lower wavelength lithography step, in which portions of the patterning layer not covered by an overlying mask are exposed to EUV or lower wavelength light; and
performing a cyclic, dry process to remove the portions of the patterning layer exposed to the EUV or lower wavelength light and develop a metal-oxide photoresist pattern.

### Claim 2 (depends on 1)

The method of claim 1, wherein the cyclic, dry process comprises:
selectively depositing a protective layer onto unexposed portions of the patterning layer by exposing the substrate to a first plasma, wherein the unexposed portions of the patterning layer are covered by the overlying mask and not exposed to the EUV or lower wavelength light;
selectively etching exposed portions of the patterning layer by exposing the substrate to a second plasma, wherein the exposed portions of the patterning layer are not covered by the overlying mask and are exposed to the EUV or lower wavelength light; and
repeating the selectively depositing and the selectively etching until the exposed portions of the patterning layer are completely removed.

### Claim 3 (depends on 2)

The method of claim 2, wherein the first plasma comprises a hydrocarbon or fluorocarbon based precursor gas.

### Claim 4 (depends on 2)

The method of claim 2, wherein the second plasma comprises a hydrogen or halogen containing precursor gas and an inert gas.

### Claim 5 (depends on 4)

The method of claim 4, wherein each time the selectively etching step is performed, the hydrogen or halogen containing precursor gas converts a surface of the exposed portions of the patterning layer into a volatile material, and ions of the inert gas bombard a surface of the substrate to remove the volatile material from the exposed portions.

### Claim 6 (depends on 5)

The method of claim 5, wherein each time the selectively depositing step is performed, a new protective layer is deposited onto the unexposed portions of the patterning layer.

### Claim 7

A method for patterning a substrate, the method comprising:
forming a patterning layer and one or more underlying layers on the substrate, wherein the patterning layer comprises a metal-oxide photoresist;
exposing portions of the patterning layer, which are not covered by a mask overlying the patterning layer, to extreme ultraviolet (EUV) or lower wavelength light;
selectively depositing a protective layer onto unexposed portions of the patterning layer by exposing the substrate to a first plasma, wherein the unexposed portions of the patterning layer are covered by the mask and not exposed to the EUV or lower wavelength light;
selectively etching exposed portions of the patterning layer by exposing the substrate to a second plasma; and
repeating the selectively depositing and the selectively etching until the exposed portions of the patterning layer are completely removed.

### Claim 8 (depends on 7)

The method of claim 7, wherein the patterning layer comprises a metal-oxide material, which includes clusters of metal-oxide structures having chemically bound organic ligands, and wherein exposing the portions of the patterning layer not covered by the patterned mask layer to EUV or lower wavelength light separates the organic ligands from the metal-oxide structures, while leaving the unexposed portions of the patterning layer unchanged.

### Claim 9 (depends on 8)

The method of claim 8, wherein after exposing the portions of the patterning layer not covered by the patterned mask layer to EUV or lower wavelength light and before selectively depositing the protective layer onto the unexposed portions of the patterning layer, the method further comprises performing a bake process to release the organic ligands from the exposed portions of the patterning layer.

### Claim 10 (depends on 7)

The method of claim 7, wherein the first plasma comprises a hydrocarbon or fluorocarbon based precursor gas.

### Claim 11 (depends on 10)

The method of claim 10, wherein the first plasma comprises CH4, C4F8, C4F6 or CH3F.

### Claim 12 (depends on 7)

The method of claim 7, wherein the second plasma comprises a hydrogen or halogen containing precursor gas.

### Claim 13 (depends on 12)

The method of claim 12, wherein the second plasma comprises CH4, CF4, CHF3 or BCl3.

### Claim 14 (depends on 12)

The method of claim 12, wherein the second plasma further comprises an inert gas.

### Claim 15 (depends on 8)

The method of claim 8, wherein the second plasma further comprises argon (Ar).

### Claim 16 (depends on 12)

The method of claim 12, wherein the hydrogen or halogen containing precursor gas converts a surface of the exposed portions of the patterning layer into a volatile material, and wherein inert gas ions bombard the surface of the exposed portions to remove the volatile material.

### Claim 17 (depends on 7)

The method of claim 7, wherein the selectively depositing a protective layer onto unexposed portions of the patterning layer and the selectively etching exposed portions of the patterning layer are performed simultaneously within a plasma processing chamber using the same plasma precursor gases to generate the first plasma and the second plasma.

### Claim 18 (depends on 17)

The method of claim 17, wherein the first plasma and the second plasma each comprise a hydrocarbon precursor and an inert gas.

### Claim 19 (depends on 7)

The method of claim 7, wherein the selectively depositing a protective layer onto unexposed portions of the patterning layer and the selectively etching exposed portions of the patterning layer are segregated within a plasma processing chamber, so that different plasma precursor gases are used to generate the first plasma and the second plasma.

### Claim 20 (depends on 19)

The method of claim 19, wherein the first plasma comprises a hydrocarbon precursor, and wherein the second plasma comprises a halocarbon precursor and an inert gas.