# US 12,181,797 B2 · Extreme ultraviolet mask with alloy based absorbers

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- Number: US 12,181,797 B2
- Document ID: US12181797B2
- Status: Granted
- Kind: B2
- Application number: 17/483,302
- Filed: 2021-09-23
- Published: 2022-12-01
- Granted: 2024-12-31
- Earliest claimed: 2021-05-28
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Co., Ltd.
- Inventors: Pei-Cheng Hsu; Ping-Hsun Lin; Ta-Cheng Lien; Hsin-Chang Lee
- Web page: https://patentgrep.com/patent/US12181797B2

## CPC

- G03F 1/24: Reflection masks; Preparation thereof
- G03F 1/54: Absorbers, e.g. of opaque materials
- G03F 1/58: having two or more different absorber layers, e.g. stacked multilayer absorbers
- G03F 1/80: Etching
- G03F 7/0042: {with inorganic or organometallic light-sensitive compounds not otherwise provided for, e.g. inorganic resists (G03F7/075 takes precedence)}
- H10P 76/405: {characterised by their composition, e.g. multilayer masks}
- H10P 76/4085: {characterised by the processes involved to create the masks}
- 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

An extreme ultraviolet mask including a substrate, a reflective multilayer stack on the substrate and a multi-layer patterned absorber layer on the reflective multilayer stack is provided. Disclosed embodiments include an absorber layer that includes an alloy comprising ruthenium (Ru), chromium (Cr), platinum (Pt), gold (Au), iridium (Ir), titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), tungsten (W) or palladium (Pd), and at least one alloying element. The at least one alloying element includes ruthenium (Ru), chromium (Cr), tantalum (Ta), platinum (Pt), gold (Au), iridium (Ir), titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), hafnium (Hf), boron (B), nitrogen (N), silicon (Si), zirconium (Zr) or vanadium (V). Other embodiments include a multi-layer patterned absorber structure with layers that include an alloy and an alloying element, where at least two of the layers of the multi-layer structure have different compositions.

## Claims

### Claim 1

A method of using an EUV mask, the method comprising:
exposing the EUV mask to an incident radiation, the EUV mask including:
a substrate;
a reflective multilayer stack on the substrate; and
a patterned absorber layer on the reflective multilayer stack, wherein the patterned absorber layer comprises a tantalum (Ta)-based alloy including Ta and at least one alloying element selected from titanium (Ti), chromium (Cr), iron (Fe), ruthenium (Ru), cobalt (Co), molybdenum (Mo), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), gold (Au), tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V), or a nitride, oxide, oxynitride, boride or carbide of the Ta-based alloy thereof; and
absorbing a portion of the incident radiation in the patterned absorber layer; and
directing a portion of the incident radiation that is not absorbed in the patterned absorber layer to a material to be patterned.

### Claim 2 (depends on 1)

The method of claim 1, wherein the Ta-based alloy of the patterned absorber layer further comprises at least one interstitial element selected from nitrogen (N), oxygen (O), boron (B), carbon (C), and combinations thereof.

### Claim 3 (depends on 1)

The method of claim 1, wherein the patterned absorber layer further includes:
a capping layer on the reflective multilayer stack;
a patterned buffer layer on the capping layer, wherein the patterned absorber layer is in contact with the patterned buffer layer; and
a hard mask layer on the patterned absorber layer, wherein the patterned absorber layer is in contact with the hard mask layer and the hard mask layer includes a hard mask material selected from SiN, TaBO, TaO, SiO, SiON, SiOB, CrON and CrN.

### Claim 4

A method of using an EUV mask, the method comprising:
exposing the EUV mask to an incident radiation, the EUV mask including:
a substrate;
a reflective multilayer stack on the substrate; and
a patterned absorber layer on the reflective multilayer stack, wherein the patterned absorber layer includes a first layer of absorber material and a second layer of absorber material different from the first layer of absorber material, the first layer of the absorber material and the second layer of absorber material each comprising an alloy including one or more of niobium (Nb), rhodium (Rh) or tungsten (W) and at least one alloying element selected from tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V), the absorber material of the first layer having an index of refraction smaller than 0.95 and an extinction coefficient greater than 0.01;
absorbing a portion of the incident radiation in the patterned absorber layer; and
directing a portion of the incident radiation that is not absorbed in the patterned absorber layer to a material to be patterned.

### Claim 5 (depends on 4)

The method of claim 4, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the EUV mask includes the absorber material of the first layer comprising an alloy including one or more of niobium (Nb), rhodium (Rh) or tungsten (W), and at least two alloying elements selected from tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V).

### Claim 6 (depends on 5)

The method of claim 5, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the EUV mask includes the absorber material of the second layer comprising an alloy including niobium (Nb), rhodium (Rh) or tungsten (W), and at least two alloying elements selected from tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V).

### Claim 7 (depends on 6)

The method of claim 6, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the EUV mask includes a third layer of absorber material, the absorber material of the third layer comprising an alloy including one or more of niobium (Nb), rhodium (Rh) or tungsten (W), and at least two alloying elements selected from tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V).

### Claim 8 (depends on 7)

The method of claim 7, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the EUV mask includes a fourth layer of absorber material, the absorber material of the fourth layer comprising an alloy including one or more of niobium (Nb), rhodium (Rh) or tungsten (W), and at least two alloying elements selected from tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V).

### Claim 9 (depends on 4)

The method of claim 4, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the EUV mask includes an absorber material of a third layer of the patterned absorber layer different in composition than the first layer and the second layer of the patterned absorber layer, the third layer comprising an alloy including niobium (Nb) and rhodium (Rh), and an alloying element of zirconium (Zr).

### Claim 10 (depends on 5)

The method of claim 5, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the EUV mask includes an absorber material of the first layer that includes at least one interstitial element selected from nitrogen (N), oxygen (O), boron (B), carbon (C), and combinations thereof.

### Claim 11 (depends on 5)

The method of claim 5, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the EUV mask includes an absorber material of the first layer that includes an alloy comprising tungsten (W), and at least one alloying element selected from titanium (Ti), niobium (Nb), rhodium (Rh), molybdenum (Mo), iridium (Ir), or zirconium (Zr).

### Claim 12 (depends on 6)

The method of claim 6, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the EUV mask includes:
a capping layer on the reflective multilayer stack;
a patterned buffer layer on the capping layer, wherein the patterned absorber layer is in contact with the patterned buffer layer; and
a hard mask layer on the patterned absorber layer, wherein the patterned absorber layer is in contact with the hard mask layer and the hard mask layer includes a hard mask material selected from SiN, TaBO, TaO, SiO, SiON and SiOB.

### Claim 13 (depends on 4)

The method of claim 4, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the EUV mask includes:
a capping layer on the reflective multilayer stack;
a patterned buffer layer on the capping layer, wherein the patterned absorber layer is in contact with the patterned buffer layer; and
a hard mask layer on the patterned absorber layer, wherein the patterned absorber layer is in contact with the hard mask layer and the hard mask layer includes a hard mask material selected from CrON and CrN.

### Claim 14

A method of using an EUV mask, the method comprising:
exposing the EUV mask to an incident radiation, the EUV mask including:
a substrate;
a reflective multilayer stack on the substrate;
a buffer layer on the reflective multilayer stack;
a first layer of absorber material on the buffer layer, wherein the absorber material of the first layer comprises an alloy including one or more of niobium (Nb), rhodium (Rh) or tungsten (W), and at least one alloying element selected from tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V); and
a second layer of absorber material on the first layer of absorber material, wherein the absorber material of the second layer is different from the absorber material of the first layer and the absorber material of the second layer comprising an alloy including one or more of niobium (Nb), rhodium (Rh) or tungsten (W), and at least one alloying element selected from tungsten (W), niobium (Nb), rhodium (Rh), hafnium (Hf), zirconium (Zr) and vanadium (V);
absorbing a portion of the incident radiation in the first layer of absorber material;
absorbing a portion of the incident radiation in the second layer of absorber material; and
directing a portion of the incident radiation that is not absorbed in the first layer of absorber material and the second layer of absorber material to a material to be patterned.

### Claim 15 (depends on 14)

The method of claim 14, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation the EUV mask, wherein the EUV mask includes a first layer of absorber material including a plurality of openings therein.

### Claim 16 (depends on 15)

The method of claim 15, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the EUV mask includes a second layer of absorber material including a plurality of openings therein.

### Claim 17 (depends on 14)

The method of claim 14, wherein the exposing the EUV mask to an incident radiation includes exposing to the incident radiation, the EUV mask, wherein the first layer of absorbent material is amorphous and the second layer of absorbent material is amorphous.

### Claim 18 (depends on 1)

The method of claim 1, wherein the Ta-based alloy in the patterned absorber layer comprises tantalum chromium (TaCr), tantalum hafnium (TaHf), tantalum iridium (TaIr), tantalum nickel (TaNi), tantalum ruthenium (TaRu), tantalum cobalt (TaCo), tantalum gold (TaAu), tantalum molybdenum (TaMo), tantalum tungsten (TaW), tantalum iron (TaFe), tantalum rhodium (TaRh), tantalum vanadium (TaV), tantalum niobium (TaNb), tantalum palladium (TaPd), tantalum zirconium (TaZr), tantalum titanium (TaTi), or tantalum platinum (TaPt).

### Claim 19 (depends on 1)

The method of claim 1, wherein the patterned absorber layer comprises TaCrN, TaHfN, TaIrN, TaNiN, TaRuN, TaCON, TaAuN, TaMoON, TaWN, TaFeN, TaRhN, TaVN, TaNbN, TaPdN, TaZrN, TaTiN, or TaPtN.

### Claim 20 (depends on 1)

The method of claim 1, wherein the patterned absorber layer comprises TaCrON, TaHfON, TalrON, TaNiON, TaRuON, TaCoON, TaAuON, TaMOON, TaWON, TaFeON, TaRhON, TaVON, TaNbON, TaPdON, TaZrON, TaTiON, TaPtON.