# US 10,483,082 B2 · Evaluation method, correction method, recording medium and electron beam lithography system

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- Number: US 10,483,082 B2
- Document ID: US10483082B2
- Status: Granted
- Kind: B2
- Application number: 15/978,747
- Filed: 2018-05-14
- Published: 2018-09-20
- Granted: 2019-11-19
- Earliest claimed: 2015-11-26
- Assignees: NuFlare Technology, Inc.
- Applicants: NuFlare Technology, Inc.
- Inventors: Rieko Nishimura
- Web page: https://patentgrep.com/patent/US10483082B2

## CPC

- H01J 37/222: {Image processing arrangements associated with the tube}
- H01J 37/09: Diaphragms; Shields associated with electron or ion-optical arrangements; Compensation of disturbing fields
- H01J 37/304: Controlling tubes by information coming from the objects {or from the beam}, e.g. correction signals
- H01J 37/3177: {Multi-beam, e.g. fly's eye, comb probe}
- H01J 2237/0435: Multi-aperture
- H01J 2237/0453: multiple apertures
- H01J 2237/30433: System calibration
- H01J 2237/30455: Correction during exposure
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

An evaluation method according to an embodiment is to evaluate a precision of an aperture formed with multiple openings, and includes steps of forming a first evaluation pattern based on evaluation data using multiple electron beams generated by electron beam that has passed through the aperture, dividing the aperture into multiple regions, each of the regions including the multiple openings and defining the multiple divided regions, forming a second evaluation pattern based on evaluation data using the electron beam that has passed through a first divided region among the multiple divided regions, comparing the first evaluation pattern with the second evaluation pattern, and evaluating the precision of the aperture based on the comparison result between the first evaluation pattern and the second evaluation pattern.

## Claims

### Claim 1

An evaluation method to evaluate a precision of an aperture formed with multiple openings, the method comprising:
forming a first evaluation pattern based on first evaluation data using multiple electron beams generated by an electron beam that has passed through the aperture;
dividing the aperture into multiple regions, each of the regions including a subset of the multiple openings that is less than all the multiple openings in the aperture, and defining the multiple divided regions;
forming a second evaluation pattern based on second evaluation data using a third evaluation pattern formed by multiple electron beams that have passed through a first divided region among the multiple divided regions;
comparing the first evaluation pattern with the second evaluation pattern; and
evaluating the precision of the aperture based on the comparison result between the first evaluation pattern and the second evaluation pattern.

### Claim 2 (depends on 1)

The evaluation method according to claim 1, wherein in forming the second evaluation pattern, the second evaluation pattern is formed for each of the divided regions.

### Claim 3 (depends on 1)

The evaluation method according to claim 1, wherein:
the first and second evaluation patterns each include a marking formed by each of the multiple electron beam; and
in comparing the first evaluation pattern with the second evaluation pattern, a size of the marking in the first evaluation pattern is compared with a size of the marking in the second evaluation pattern corresponding to the marking in the first evaluation pattern.

### Claim 4 (depends on 1)

The evaluation method according to claim 1, wherein in forming the second evaluation pattern:
the second evaluation pattern is formed for each of the divided regions; and
in comparing the first evaluation pattern with the second evaluation pattern, the first evaluation pattern is compared with each of the second evaluation patterns formed for each of the divided regions.

### Claim 5 (depends on 1)

The evaluation method according to claim 1, wherein in evaluating the precision of the aperture, the precision of the aperture is evaluated based on a deviation between a size of a marking in the first evaluation pattern and a size of a marking in the second evaluation pattern corresponding to the marking in the first evaluation pattern.

### Claim 6 (depends on 1)

The evaluation method according to claim 1, wherein in comparing the first evaluation pattern with the second evaluation pattern, the first evaluation pattern and the second evaluation pattern are compared with each other for each of the divided regions.

### Claim 7 (depends on 6)

The evaluation method according to claim 6, wherein in evaluating the precision of the aperture, the precision of the aperture is evaluated based on a number of the divided regions having the evaluation that is equal to or smaller than a threshold.

### Claim 8

A recording medium storing a program causing a controller for an electron beam lithography system including an aperture formed with multiple openings to execute:
forming a first evaluation pattern based on first evaluation data using multiple electron beams generated by an electron beam that has passed through the aperture;
dividing the aperture into multiple regions, each of the multiple regions including a subset of the multiple openings that is less than all the multiple openings in the aperture, and defining the multiple divided regions;
forming a second evaluation pattern based on second evaluation data using a third evaluation pattern formed by multiple electron beams that have passed through a first divided region among the multiple divided regions;
comparing the first evaluation pattern with the second evaluation pattern; and
evaluating a precision of the aperture based on a comparison result between the first evaluation pattern and the second evaluation pattern.

### Claim 9

An electron beam lithography system comprising an aperture formed with multiple openings, and forming a pattern on a sample, the system comprising:
a memory storing a program; and
a controller executing the program stored in the memory,
wherein the program is to execute:
forming a first evaluation pattern based on first evaluation data using multiple electron beams generated by an electron beam that has passed through the aperture;
dividing the aperture into multiple regions, each of the multiple regions including a subset of the multiple openings that is less than all the multiple openings in the aperture, and defining the multiple divided regions;
forming a second evaluation pattern based on second evaluation data using a third evaluation pattern formed by multiple electron beams that have passed through a first divided region among the multiple divided regions;
comparing the first evaluation pattern with the second evaluation pattern; and
evaluating the precision of the aperture based on the comparison result between the first evaluation pattern and the second evaluation pattern.