# US 6,741,732 B2 · Exposure method and device manufacturing method using this exposure method

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- Number: US 6,741,732 B2
- Document ID: US6741732B2
- Status: Granted
- Kind: B2
- Application number: 09/166,595
- Filed: 1998-10-06
- Published: 2004-04-15
- Granted: 2004-05-25
- Earliest claimed: 1997-10-09
- Assignees: Canon Kabushiki Kaisha
- Inventors: Yoshikiyo Yui
- Web page: https://patentgrep.com/patent/US6741732B2

## CPC

- G03F 7/70508: {Data handling in all parts of the microlithographic apparatus, e.g. handling pattern data for addressable masks or data transfer to or from different components within the exposure apparatus}
- G03F 7/70358: {Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging}
- G03F 7/7045: {Hybrid exposures, i.e. multiple exposures of the same area using different types of exposure apparatus, e.g. combining projection, proximity, direct write, interferometric, UV, x-ray or particle beam}
- G03F 7/70633: {Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching}
- H01J 2237/31757: hybrid, i.e. charged particles and light, X-rays, plasma
- 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)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

In an exposure method of drawing and exposing a second pattern with a scanner so as to match a first pattern formed on a sample upon exposure with a reduction projection exposure apparatus, a matrix is set on the sample. A distortion correction map representing an offset of a point corresponding to each matrix point on the first pattern from an ideal position is formed. The blocks of the matrix, small for a large offset and large for a small offset, are set when drawing the second pattern while correcting drawing information of the second pattern on the basis of offset information represented by the correction map. The block size of the distortion correction map is not uniformly reduced. A small block size is set for a large distortion, and a large block size is set for a small distortion, thereby reducing the data amount. A necessary and sufficient block size is set for distortion correction to minimize the number of times of arithmetic operation for correction processing without increasing the memory size, thereby achieving high-speed processing.

## Claims

### Claim 1

An exposure method of exposing a second pattern with a second exposure apparatus so as to match a first pattern formed on a sample upon exposure with a first exposure apparatus, said method comprising the steps of:
setting a matrix on the sample;
measuring or calculating an offset of a point corresponding to each matrix point on the first pattern from an ideal position;
forming a distortion correction map representing the measured or calculated offset, wherein a block pitch of a first portion is larger than a block pitch of a second portion on the matrix, an offset in the first portion is smaller than an offset of the second portion, the block pitches are selected based on a required overlay accuracy between the first pattern and the second pattern; and
exposing the second pattern on the basis of the distortion correction map,
wherein the overlay accuracy is an accuracy of relative position between the first pattern and the second pattern.

### Claim 2 (depends on 1)

The method according to claim 1, further comprising the step of exposing the first pattern after the second pattern.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the block pitch of the second portion is 20 μm to 250 μm.

### Claim 4 (depends on 2)

A device manufacturing method comprising:
an exposure step of exposing a sample by using the exposure method of claim 2; and
a development step of developing the sample.

### Claim 5 (depends on 1)

The method according to claim 1, further comprising the step of exposing the first pattern prior to the second pattern.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the block pitch of the second portion is 20 μm to 250 μm.

### Claim 7 (depends on 6)

A device manufacturing method comprising:
an exposure step of exposing a sample by using the exposure method of claim 6; and
a development step of developing the sample.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the second exposure apparatus is an electron beam exposure apparatus.

### Claim 9 (depends on 1)

A device manufacturing method comprising:
an exposure step of exposing a sample using the exposure method of claim 1; and
a development step of developing the sample.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the forming step includes performing coarse setting for the block pitch by thinning the offset data of the matrix points.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the forming step includes performing fine setting for the block pitch by adding the offset data of the matrix points.

### Claim 12 (depends on 1)

An exposure apparatus comprising:
a controller for performing exposure by using the method of claim 1.

### Claim 13 (depends on 1)

The method according to claim 1, wherein the sample includes a plurality of chip portions, and, in the center of each chip portion, the block pitch is larger than the block pitch of the other portions.

### Claim 14 (depends on 1)

The method according to claim 1, wherein the first apparatus is a reduction projection exposure apparatus.

### Claim 15 (depends on 1)

The method according to claim 1, further comprising the step of correcting drawing information of the second pattern on the basis of offset information represented by the distortion correction map,
wherein the second pattern is exposed on the basis of the corrected drawing information.

### Claim 16 (depends on 1)

The method according to claim 1, wherein the measuring or calculating step performs processing which measures the offset by observing an actual element pattern.

### Claim 17 (depends on 1)

The method according to claim 1, wherein the measuring or calculating step performs processing which measures the offset by observing marks, which are formed on the sample, for exposure distortion measurement.

### Claim 18 (depends on 1)

The method according to claim 1, wherein the measuring or calculating step calculates the offset based on data about the lens distortion of the first exposure apparatus measured in advance.

### Claim 19

An exposure method of exposing a second pattern with a second exposure apparatus so as to match a first pattern formed on a sample upon exposure with a first exposure apparatus, said method comprising the steps of:
setting a matrix on the sample;
measuring or calculating an offset of a point corresponding to each matrix point on the first pattern from an ideal position, wherein a block pitch of a first portion is larger than a block pitch of a second portion on the matrix, an offset in the first position is smaller than an offset of the second position, the block pitches are selected based on a required overlay accuracy between the first pattern and the second pattern; and
exposing the second pattern on the basis of the measured or calculated offset,
wherein the overlay accuracy is a relative position accuracy between the first pattern and the second pattern.

### Claim 20

An exposure apparatus comprising:
a controller for performing exposure by using an exposure method of exposing a second pattern with a second exposure apparatus so as to match a first pattern formed on a sample upon exposure with a first exposure apparatus;
wherein the method comprises the steps of:
setting a matrix on the sample;
measuring or calculating an offset of a point corresponding to each matrix point on the first pattern from an ideal position, wherein a block pitch of a first portion is larger than a block pitch of a second portion on the matrix, an offset of the first portion is smaller than an offset of the second portion, the block pitches are selected based on a required overlay accuracy between the first pattern and the second pattern; and
exposing the second pattern on the basis of a measured or calculated offset,
wherein said overlay accuracy is a relative position accuracy between the first pattern and the second pattern.