# US 2017/0285487 A1 · Lithographic apparatus and a method of operating the apparatus

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2017/0285487 A1
- Document ID: US20170285487A1
- Status: Published application
- Kind: A1
- Application number: 15/623,091
- Filed: 2017-06-14
- Published: 2017-10-05
- Earliest claimed: 2009-05-01
- Assignees: ASML Netherlands B.V.
- Applicants: Asml Netherlands B.V.
- Inventors: Ivo Adam Johannes THOMAS; Siebe LANDHEER; Arnout Johannes MEESTER; Marcio Alexandre Cano MIRANDA; Gheorghe TANASA
- Web page: https://patentgrep.com/patent/US20170285487A1

## CPC

- 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)}
- G03B 27/52: Details
- G03F 7/70891: {Temperature}
- 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)
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)

## Abstract

A lithographic apparatus comprising a projection system, and a liquid confinement structure configured to at least partly confine immersion liquid to an immersion space defined by the projection system, the liquid confinement structure and a substrate and/or substrate table is disclosed wherein a measure is taken to reduce the effect of droplets and/or a liquid film on the last element of the projection system.

## Claims

### Claim 1

A lithographic apparatus comprising:
a projection system;
a liquid confinement structure configured at least partly to confine immersion liquid to an immersion space defined by the projection system, the liquid confinement structure and a substrate and/or substrate table; and
a member adjacent an optically active part of a final element of the projection system, wherein, in normal use, the member is between immersion liquid and the optically active part.

### Claim 2 (depends on 1)

The lithographic apparatus of claim 1, wherein the member is configured to reduce a temperature variation in the optically active part due to a thermal load caused by evaporation of immersion liquid.

### Claim 3 (depends on 2)

The lithographic apparatus of claim 2, wherein evaporation of immersion liquid is evaporation of droplets of immersion liquid and/or evaporation of immersion liquid in the immersion space.

### Claim 4 (depends on 1)

The lithographic apparatus of claim 1, wherein the member is configured to spread a heat load applied to a localized area of the member by immersion liquid on it onto an area of the optically active part greater than the localized area.

### Claim 5 (depends on 4)

The lithographic apparatus of claim 4, wherein the spreading is achieved by thermal conduction.

### Claim 6 (depends on 4)

The lithographic apparatus of claim 4, wherein the spreading is achieved by increasing the area in which any liquid from a droplet is in contact with the member.

### Claim 7 (depends on 6)

The lithographic apparatus of claim 6, wherein the increasing is by capillary action.

### Claim 8 (depends on 1)

The lithographic apparatus of claim 1, wherein the member is comprised of a material having a higher co-efficient of thermal conductivity than the material of the optically active part.

### Claim 9 (depends on 1)

The lithographic apparatus of claim 1, wherein the member is comprised of a metal.

### Claim 10 (depends on 1)

The lithographic apparatus of claim 1, wherein, in use, a meniscus of immersion liquid extends between the liquid confinement structure and the member.

### Claim 11 (depends on 1)

The lithographic apparatus of claim 1, wherein the member is sealed to the final element at one end.

### Claim 12 (depends on 1)

The lithographic apparatus of claim 1, wherein the member is comprised of a material different to the material of the final element.

### Claim 13 (depends on 1)

The lithographic apparatus of claim 1, wherein the member is a coating.

### Claim 14 (depends on 1)

The lithographic apparatus of claim 1, wherein the member is spaced from the final element at least at a central portion.

### Claim 15 (depends on 1)

The lithographic apparatus of claim 1, wherein the member is in direct physical contact with the final element.

### Claim 16 (depends on 1)

The lithographic apparatus of claim 1, wherein the immersion liquid which is on the opposite side of the member to the optically active part is a droplet of immersion liquid which is separated from the immersion liquid in the immersion space.