EFFECTIVE LIGHT SOURCE SHAPE DATABASE GENERATION METHOD, OPTICAL IMAGE CALCULATION METHOD, RECORDING MEDIUM, EXPOSURE METHOD, AND DEVICE FABRICATION METHOD

• US 20090231562A1
• Filed: 02/11/2009
• Published: 09/17/2009
• Est. Priority Date: 02/13/2008
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Yoshii, Hiroto, Mikami, Koji, Tsujita, Kouichirou
• Granted Patent: US 8,582,083 B2
• Time in Patent Office: Days
• US Class Current: 355/53
• CPC Class Codes: G03F 7/70091 Illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane; On-axis or off-axis settings, e.g. annular, dipole or quadrupole settings; Partial coherence control, i.e. sigma or numerical aperture [NA]
• CPC Class Codes: G03F 7/70108 Off-axis setting using a light-guiding element, e.g. diffractive optical elements [DOEs] or light guides
• CPC Class Codes: 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

Abstract

The present invention provides a method of generating a database of effective light source shapes including a generation step of generating an initial database representing an effective light source shapes corresponding to a plurality of conditions settable for an illumination optical system, a measurement step of setting an arbitrary condition for the illumination optical system, and measuring an effective light source shape, a calculation step of calculating a difference amount between an effective light source shape when each of the plurality of conditions is set for the illumination optical system and the effective light source shape included in the initial database, and a correction step of correcting the effective light source shapes included in the initial database using the difference amounts and compiling the corrected effective light source shapes into an actual database.

Claims

1. In an exposure apparatus including an illumination optical system which illuminates an original with light from a light source, and a projection optical system which projects a pattern of the original onto a substrate, a method of generating a database of effective light source shapes formed in the illumination optical system, the method comprising:

a generation step of calculating effective light source shapes while changing a plurality of conditions settable for the illumination optical system, and generating an initial database representing the effective light source shapes corresponding to the plurality of conditions;

a measurement step of setting an arbitrary condition of the plurality of conditions for the illumination optical system, and measuring an effective light source shape;

a calculation step of calculating, based on the effective light source shape measured in the measurement step, and an effective light source shape corresponding to the arbitrary condition included in the initial database generated in the generation step, a difference amount between an effective light source shape when each of the plurality of conditions is set for the illumination optical system and the effective light source shape included in the initial database; and

a correction step of correcting the effective light source shapes included in the initial database using the difference amounts calculated in the calculation step, and compiling the corrected effective light source shapes into an actual database.

2. The method according to claim 1, wherein in the calculation step, the difference amount is calculated as an orthogonal function.

3. The method according to claim 1, wherein in the measurement step, at least two conditions of the plurality of conditions are set for the illumination optical system, and effective light source shapes corresponding to said at least two conditions are measured.

4. Of a first exposure apparatus and a second exposure apparatus each including an illumination optical system which illuminates an original with light from a light source, and a projection optical system which projects a pattern of the original onto a substrate, a method of generating a database of effective light source shapes formed in the illumination optical system of the second exposure apparatus, the method comprising:

an obtaining step of obtaining, as an initial database, a database representing effective light source shapes corresponding to a plurality of conditions settable for the illumination optical system of the first exposure apparatus;

a measurement step of setting, for the illumination optical system of the second exposure apparatus, an arbitrary condition of the plurality of conditions settable for the illumination optical system of the second exposure apparatus, and measuring an effective light source shape;

a calculation step of calculating, based on the effective light source shape measured in the measurement step, and an effective light source shape corresponding to the arbitrary condition included in the initial database obtained in the obtaining step, a difference amount between an effective light source shape when each of the plurality of conditions is set for the illumination optical system of the second exposure apparatus and the effective light source shape included in the initial database; and

a correction step of correcting the effective light source shapes included in the initial database using the difference amounts calculated in the calculation step, and compiling the corrected effective light source shapes into an actual database.

5. A method of calculating an optical image formed on an image plane of a projection optical system in an exposure apparatus including an illumination optical system which illuminates an original with light from a light source, and the projection optical system which projects a pattern of the original onto the substrate, the method comprising:

a database generation step of generating a database of effective light source shapes formed in the illumination optical system; and

a calculation step of receiving, as input information, the effective light source shapes included in the database generated in the database generation step, the pattern of the original, and information concerning the projection optical system, and calculating an optical image formed on the image plane of the projection optical system based on the input information,

the database generation step including;

a generation step of calculating effective light source shapes while changing a plurality of conditions settable for the illumination optical system, and generating an initial database representing the effective light source shapes corresponding to the plurality of conditions,

a measurement step of setting an arbitrary condition of the plurality of conditions for the illumination optical system, and measuring an effective light source shape,

a calculation step of calculating, based on the effective light source shape measured in the measurement step, and an effective light source shape corresponding to the arbitrary condition included in the initial database generated in the generation step, a difference amount between an effective light source shape when each of the plurality of conditions is set for the illumination optical system and the effective light source shape included in the initial database, and

a correction step of correcting the effective light source shapes included in the initial database using the difference amounts calculated in the calculation step, and compiling the corrected effective light source shapes into an actual database.

6. A recording medium recording a program for making a computer calculate an optical image formed on an image plane of a projection optical in an exposure apparatus including an illumination optical system which illuminates an original with light from a light source, and the projection optical system which projects a pattern of the original onto the substrate, the program making the computer execute:

a database generation step of generating a database of effective light source shapes formed in the illumination optical system; and

a calculation step of receiving, as input information, the effective light source shapes included in the database generated in the database generation step, the pattern of the original, and information concerning the projection optical system, and calculating an optical image formed on the image plane of the projection optical system based on the input information,

wherein the database generation step includes;

a generation step of calculating effective light source shapes while changing a plurality of conditions settable for the illumination optical system, and generating an initial database representing the effective light source shapes corresponding to the plurality of conditions,

a measurement step of setting an arbitrary condition of the plurality of conditions for the illumination optical system, and measuring an effective light source shape,

a calculation step of calculating, based on the effective light source shape measured in the measurement step, and an effective light source shape corresponding to the arbitrary condition included in the initial database generated in the generation step, a difference amount between an effective light source shape when each of the plurality of conditions is set for the illumination optical system and the effective light source shape included in the initial database, and

a correction step of correcting the effective light source shapes included in the initial database using the difference amounts calculated in the calculation step, and compiling the corrected effective light source shapes into an actual database.

7. An exposure method for an exposure apparatus including an illumination optical system which illuminates an original with light from a light source, and a projection optical system which projects a pattern of the original onto a substrate, the method comprising:

a database generation step of generating a database of effective light source shapes formed in the illumination optical system;

a calculation step of receiving, as input information, the effective light source shapes included in the database generated in the database generation step, the pattern of the original, and information concerning the projection optical system, and calculating an optical image formed on an image plane of the projection optical system based on the input information;

a setting step of setting an exposure condition of the exposure apparatus based on evaluation of the optical image calculated in the calculation step;

an illumination step of illuminating the original under the exposure condition set in the setting step; and

a projection step of projecting an image of the pattern of the original illuminated in the illumination step onto the substrate via the projection optical system,

wherein the database generation step includes;

a generation step of calculating effective light source shapes while changing a plurality of conditions settable for the illumination optical system, and generating an initial database representing the effective light source shapes corresponding to the plurality of conditions,

a measurement step of setting an arbitrary condition of the plurality of conditions for the illumination optical system, and measuring an effective light source shape,

a calculation step of calculating, based on the effective light source shape measured in the measurement step, and an effective light source shape corresponding to the arbitrary condition included in the initial database generated in the generation step, a difference amount between an effective light source shape when each of the plurality of conditions is set for the illumination optical system and the effective light source shape included in the initial database, and

a correction step of correcting the effective light source shapes included in the initial database using the difference amounts calculated in the calculation step, and compiling the corrected effective light source shapes into an actual database.

8. A device fabrication method comprising steps of:

exposing a substrate using an exposure method according to claim 7; and

performing a development process for the substrate exposed.