# US 7,746,445 B2 · Lithographic apparatus, device manufacturing method and a substrate

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- Number: US 7,746,445 B2
- Document ID: US7746445B2
- Status: Granted
- Kind: B2
- Application number: 11/642,912
- Filed: 2006-12-21
- Published: 2007-05-10
- Granted: 2010-06-29
- Earliest claimed: 2003-07-28
- Assignees: ASML Netherlands B.V.
- Inventors: Marcel Mathijs Theodore Marie Dierichs; Johannes Catharinus Hubertus Mulkens; Bob Streefkerk
- Web page: https://patentgrep.com/patent/US7746445B2

## CPC

- G03F 7/70958: {Optical materials or coatings, e.g. with particular transmittance, reflectance or anti-reflection properties}
- G03F 7/70341: {Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply (chemical composition of immersion liquids G03F7/2041)}
- 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)

## Abstract

A substrate is provided with a coating of material which is substantially transparent to the wavelength of the projection beam. The coating may be thicker than the wavelength of the projection beam and have a refractive index of the coating such that the wavelength of the projection beam is shortened as it passes through it. This allows the imaging of smaller features on the substrate. Alternatively, the coating may be used with a liquid supply system and act to keep bubbles away from a radiation sensitive layer of the substrate.

## Claims

### Claim 1

A lithographic apparatus, comprising:
a lithographic projection apparatus arranged to transfer a pattern to a radiation-sensitive layer of a substrate using a beam of radiation having an exposure wavelength;
a coater arranged to at least partially coat the substrate with a layer of non-radiation-sensitive coating material which is at least partially transparent to radiation of the exposure wavelength, wherein the layer of non-radiation-sensitive coating material is positioned before the layer of radiation-sensitive material in the path of the beam of radiation, and wherein, in use, the coater applies the layer of non-radiation-sensitive coating material to a thickness which is greater than the exposure wavelength; and
a liquid supply system configured to provide a liquid to a space between a projection system of the lithographic projection apparatus and the non-radiation sensitive layer of the substrate to be in contact with the non-radiation sensitive layer.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the coater is further arranged to at least partially coat the substrate with a protective material to protect the layer of radiation-sensitive material prior to coating the substrate with the non-radiation-sensitive coating material.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein the protective material is or becomes substantially solid.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the coater is further arranged to at least partially cover the non-radiation-sensitive coating material with an evaporation prevention material configured to prevent the non-radiation-sensitive coating material from evaporating.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the coating material has a refractive index in the range of from 1.0 to 1.9.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the coating material is substantially water.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein the thickness is at least 5 μm.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein the non-radiation sensitive material has a first refractive index, the liquid has a second refractive index, and the first refractive index is within 0.2 of the second refractive index.

### Claim 9 (depends on 1)

The apparatus of claim 1, wherein the non-radiation sensitive material is substantially insoluble in and unreactive with the liquid.

### Claim 10 (depends on 1)

The apparatus of claim 1, wherein the coater is configured to coat the non-radiation sensitive material to a thickness effective to substantially reduce the effect of bubbles in the liquid, of particles in the liquid, or both, on the quality of the patterned beam impinging on the radiation sensitive layer.

### Claim 11 (depends on 1)

The apparatus of claim 1, wherein the non-radiation sensitive material is a material different than that of the liquid.

### Claim 12 (depends on 1)

The apparatus of claim 1, wherein the layer of non-radiation sensitive material is or becomes a substantially solid or gel.

### Claim 13

A lithographic apparatus, comprising:
a lithographic projection apparatus arranged to transfer a pattern to a radiation-sensitive layer of a substrate using a beam of radiation and configured to provide a liquid to a space between a projection system of the lithographic projection apparatus and a layer of non-radiation sensitive coating material of the substrate to be in contact with the layer of non-radiation sensitive coating material; and
a coater arranged to at least partially coat the substrate with the layer of non-radiation-sensitive coating material which is at least partially transparent to radiation of the exposure wavelength, wherein the layer of non-radiation-sensitive coating material is positioned before the layer of radiation-sensitive material in the path of the beam of radiation, and wherein, in use, the coater applies the layer of non-radiation sensitive material to a thickness effective to substantially reduce the effect of bubbles in the liquid, of particles in the liquid, or both, on the quality of the beam impinging on the radiation sensitive layer.

### Claim 14 (depends on 13)

The apparatus of claim 13, wherein the coater is further arranged to at least partially coat the substrate with a protective material to protect the layer of radiation-sensitive material prior to coating the substrate with the non-radiation-sensitive coating material.

### Claim 15 (depends on 13)

The apparatus of claim 13, wherein the coater is further arranged to at least partially cover the non-radiation-sensitive coating material with an evaporation prevention material configured to prevent the non-radiation-sensitive coating material from evaporating.

### Claim 16 (depends on 13)

The apparatus of claim 13, wherein the coating material is substantially water.

### Claim 17

A lithographic apparatus, comprising:
a lithographic projection apparatus arranged to transfer a pattern to a radiation-sensitive layer of a substrate using a beam of radiation having an exposure wavelength; and
a coater arranged to at least partially coat the substrate with a layer of non-radiation-sensitive coating material which is at least partially transparent to radiation of the exposure wavelength, wherein the layer of non-radiation-sensitive coating material is positioned before the layer of radiation-sensitive material in the path of the beam of radiation, and wherein, in use, the coater applies the layer of non-radiation-sensitive coating material to a thickness which is greater than the exposure wavelength before the substrate is moved to the pattern transfer location and the layer of non-radiation-sensitive coating material has a free top surface during such movement.

### Claim 18 (depends on 17)

The apparatus of claim 17, wherein the layer of non-radiation sensitive material is or becomes a substantially solid or gel.

### Claim 19 (depends on 17)

The apparatus of claim 17, wherein the coater is further arranged to at least partially cover the non-radiation-sensitive coating material with an evaporation prevention material configured to prevent the non-radiation-sensitive coating material from evaporating.

### Claim 20

A substrate for use in a lithographic projection apparatus, the substrate being at least partly covered by a radiation sensitive layer, the radiation sensitive layer being at least partly covered with non-radiation sensitive material which is at least partly transparent to said radiation and being of a different material than an immersion liquid through which a patterned beam of said radiation of the lithographic projection apparatus is projected onto a target portion of said substrate, wherein the non-radiation sensitive material has a thickness and the radiation has a wavelength and the thickness is greater than said wavelength.

### Claim 21 (depends on 20)

The substrate of claim 20, wherein said non-radiation sensitive material has a thickness of at least 5 μm.

### Claim 22 (depends on 21)

The substrate of claim 21, wherein said non-radiation sensitive material has a thickness of one of at least 10 μm and at least 20 μm.

### Claim 23 (depends on 20)

The substrate of claim 20, wherein said non-radiation sensitive material has a first refractive index and said immersion liquid has a second refractive index, and said first refractive index is within 0.2 of said second refractive index.

### Claim 24 (depends on 23)

The substrate of claim 23, wherein said first refractive index is one of within 0.1 of and substantially the same as said second refractive index.

### Claim 25 (depends on 20)

The substrate of claim 20, wherein said non-radiation sensitive material has a refractive index in the range of 1.0 to 1.7.

### Claim 26 (depends on 20)

The substrate of claim 20, wherein a further protective material is present between said radiation sensitive layer and said non-radiation sensitive layer.

### Claim 27 (depends on 20)

The substrate of claim 20, wherein said non-radiation sensitive material is substantially insoluble in and unreactive with said immersion liquid.

### Claim 28 (depends on 20)

The substrate of claim 20, wherein the non-radiation sensitive layer is of a thickness effective to substantially reduce the effect of at least one of bubbles and particles in said immersion liquid on the quality of a patterned beam impinging on the radiation sensitive layer.