Evaluation method, storage medium, exposure apparatus, exposure method, and method of manufacturing article

Patent metadata

Field	Value
Publication number	US-9996916-B2
Application number	US-201615227355-A
Country	US
Kind code	B2
Filing date	Aug 3, 2016
Priority date	Aug 10, 2015
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

The present invention provides an evaluation method of evaluating optical characteristics of a projection optical system by obtaining, by a prediction formula, a predicted value for a fluctuation amount of the optical characteristics relative to an exposure period of a substrate via the projection optical system, the method comprising determining the prediction formula by using a dedicated pattern in which a plurality of marks are arranged in a matrix on an object plane of the projection optical system, wherein the determining includes selecting, from the plurality of marks, at least two marks located in an illuminated region to be formed on the object plane when exposing the substrate, and obtaining the prediction formula based on positions of images of the at least two marks formed on an image plane of the projection optical system.

First claim

What is claimed is:

1. An evaluation method of evaluating optical characteristics of a projection optical system, by using a prediction formula for predicting a fluctuation amount of the optical characteristics relative to an exposure period of a substrate via the projection optical system, the method comprising:
determining the prediction formula by using a dedicated pattern in which a plurality of marks are arranged in a matrix on an object plane of the projection optical system,
wherein the determining includes
selecting, based on information on an illuminated region on the object plane determined in accordance with a size of a shot region on the substrate, at least two marks from marks to be located in the illuminated region among the plurality of marks, and
obtaining the prediction formula based on positions of images of the at least two marks formed on an image plane of the projection optical system.

2. The method according to claim 1 , wherein in the determining, the prediction formula is determined by using an original where the dedicated pattern has been formed.

3. The method according to claim 1 , wherein in the obtaining, a coefficient included in the predication formula is obtained based on an actually measured value of the optical characteristics obtained from the positions of the images of the at least two marks.

4. The method according to claim 1 , wherein in the dedicated pattern, not less than 100 marks are located in a maximum illuminable region on the object plane.

5. The method according to claim 1 , wherein in the dedicated pattern, the marks are located, in a longitudinal direction and a shorter side direction, respectively, in a maximum illuminable region on the object plane, at a pitch shorter than one-tenth of a dimension of the region.

6. The method according to claim 1 , wherein in the selecting, based on information on conditions for locations and number of marks to be selected in the illuminated region for respective items of the optical characteristics, the at least two marks to be used for item of the optical characteristics to be evaluated are selected.

7. The method according to claim 6 , wherein the items of the optical characteristics include at least one of a projection magnification, a distortion, a focus, curvature of field, and a difference between a longitudinal magnification and a lateral magnification.

8. The method according to claim 1 , wherein the determining includes obtaining information on the size of the shot region to be exposed and determining the illuminated region based on the obtained size of the shot region.

9. A non-transitory computer-readable storage medium storing a program for causing a computer to execute each step of an evaluation method of evaluating optical characteristics of a projection optical system, by using a prediction formula for predicting a fluctuation amount of the optical characteristics relative to an exposure period of a substrate via the projection optical system, the method comprising:
determining the prediction formula by using a dedicated pattern in which a plurality of marks are arranged in a matrix on an object plane of the projection optical system,
wherein the determining includes
selecting, based on information on an illuminated region on the object plane determined in accordance with a size of a shot region on the substrate, at least two marks from marks to be located in the illuminated region among the plurality of marks, and
obtaining the prediction formula based on positions of images of the at least two marks formed on an image plane of the projection optical system.

10. An exposure apparatus which exposes a substrate, the apparatus comprising:
a projection optical system configured to project a pattern of the original onto the substrate;
a change unit configured to change optical characteristics of the projection optical system; and
a control unit configured to determine, by using a dedicated pattern where a plurality of marks are arranged in a matrix on an object plane of the projection optical system, a prediction formula for predicting a fluctuation amount of the optical characteristics relative to an exposure period, and control the change unit based on the predicted fluctuation amount by the prediction formula,
wherein the control unit
selects, based on information on an illuminated region on the object plane determined in accordance with a size of a shot region on the substrate, at least two marks from marks to be located in the illuminated region among the plurality of marks, and
obtains the prediction formula based on positions of images of the at least two marks formed on an image plane of the projection optical system.

11. An exposure method of exposing a substrate via a projection optical system, the method comprising:
determining, by using a dedicated pattern where a plurality of marks are arranged in a matrix on an object plane of the projection optical system, a prediction formula for predicting a fluctuation amount of optical characteristics of the projection optical system relative to an exposure period; and
exposing the substrate via the projection optical system by adjusting the optical characteristics of the projection optical system based on the predicted fluctuation amount by the prediction formula,
wherein the determining includes
selecting, based on information on an illuminated region on the object plane determined in accordance with a size of a shot region on the substrate, at least two marks from marks to be located in the illuminated region among the plurality of marks, and
obtaining the prediction formula based on positions of images of the at least two marks formed on an image plane of the projection optical system.

12. A method of manufacturing an article, the method comprising:
exposing a substrate using an exposure method of exposing a substrate via a projection optical system;
developing the exposed substrate; and
processing the developed substrate to manufacture the article,
wherein the exposure method includes:
determining, by using a dedicated pattern where a plurality of marks are arranged in a matrix on an object plane of the projection optical system, a prediction formula for predicting a fluctuation amount of optical characteristics of the projection optical system relative to an exposure period; and
exposing the substrate via the projection optical system by adjusting the optical characteristics of the projection optical system based on the predicted fluctuation amount by the prediction formula,
wherein the determining includes
selecting, based on information on an illuminated region on the object plane determined in accordance with a size of a shot region on the substrate, at least two marks from marks to be located in the illuminated region among the plurality of marks, and
obtaining the prediction formula based on positions of images of the at least two marks formed on an image plane of the projection optical system.

13. The method according to claim 1 , wherein the illuminated region is determined so as to illuminate a region in which a circuit pattern of an original to be transferred onto the shot region is arranged.

14. The method according to claim 1 , wherein the at least two marks to be selected in the selecting are changed in accordance with a size of the illuminated region.

Assignees

• Canon Kk

Inventors

• Hoshino Tomohiro
• Sasaki Ryo

Classifications

• G03F7/70591 Primary

  Testing optical components · CPC title

• G03F7/706

  Aberration measurement · CPC title

• G06T2207/10056

  Microscopic image · CPC title

• G06T2207/30208

  Marker matrix · CPC title

• G03F7/70666

  Aerial image, i.e. measuring the image of the patterned exposure light at the image plane of the projection system · CPC title