Positioning method and apparatus

• US 5,521,036 A
• Filed: 03/23/1995
• Issued: 05/28/1996
• Est. Priority Date: 07/27/1992
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Iwamoto, Yoshichika, Magome, Nobutaka, Okamoto, Hiroki, Tateno, Hiroki
• Primary Examiner(s): ROSASCO, STEPHEN D
• Application Number:
  US08/409,921
• Time in Patent Office: 432 Days
• Field of Search: 430/5, 430/22, 430/312, 430/322, 356/400, 356/401, 250/548
• US Class Current: 430/22
• CPC Class Codes: G03F 9/7026 Focusing

Abstract

A positioning method involving the following steps is disclosed. Measured are coordinates positions of at least three preselected exposure areas on a static coordinate system among a plurality of exposure areas two-dimensionally formed in accordance with predetermined array coordinates on a photosensitive substrate. Calculative array coordinates of the plurality of exposure areas on the static coordinate system are calculated by using a plurality of first parameters calculated by statistically calculating the plurality of measured coordinate positions. Then, the photosensitive substrate is positioned in an exposure position while being moved in accordance with the calculative array coordinates thus calculated. Specific marks formed on a mask are thus exposed on each of a plurality of predetermined positions on the photosensitive substrate. Measured further are coordinate positions of latent images of at least three specific marks on the static coordinate system among images (latent images) of a plurality of specific marks exposed. The plurality of these measured coordinate positions are statistically calculated, thereby calculating a plurality of second parameters used for obtaining coordinate positions of each of the plurality of specific marks (latent images) on the static coordinate system. Next, each of the plurality of exposure areas on the photosensitive substrate is aligned with an exposure position in accordance with a deviation between the parameter representing an array offset among the plurality of first parameters and the parameter representing an array offset among the plurality of second parameters. Besides, particularly the specific marks of the mask are exposed within a non-exposure domain (where no base pattern is formed) in the vicinity of the outer periphery of the photosensitive substrate.

Claims

1. An apparatus for exposing patterns formed on a mask on each of a plurality of exposure areas of a photosensitive substrate, said apparatus comprising:

a stage for two-dimensionally moving said photosensitive substrate while holding said substrate;

a first measuring means for measuring respective positions when aligning some of said plurality of exposure areas with a predetermined fiducial position within a static coordinate system for defining moving positions of said stage, said first measuring means including a mark detection system for detecting alignment marks of said exposure areas;

a calculating means for determining parameters in a predetermined calculation formula used for calculating respective array coordinate values of said plurality of exposure areas by statistically calculating said plurality of positions measured by said first measuring means, said calculating means calculating array coordinate values of at least one predetermined specific area on said photosensitive substrate on the basis of said calculation formula including said determined parameters;

a means for exposing specific marks formed on said mask on said specific area by moving said stage in accordance with said calculated array coordinate values;

a second measuring means for measuring positions when aligning at least said one specific area with a predetermined fiducial position within said static coordinate system, said second measuring means including a latent image detection system for detecting latent images of said specific marks exposed; and

a means for correcting a positional relationship of said mask pattern versus each of the plurality of exposure areas on said photosensitive substrate on the basis of at least one of deviations between said positioned measured by said second measuring means and said positions calculated by said calculation means.

2. A method of transferring the pattern of a mask to a plurality of areas on a substrate, comprising:

the first step of measuring the coordinates positions of some of said plurality of areas on a stationary coordinates system prescribing the moved position of said substrate, and statistically calculating said plurality of coordinates positions to thereby calculate the parameter of a first function corresponding to the arrangement of said plurality of areas;

the second step of calculating the coordinates position of each of a plurality of particular areas on said substrate on said stationary coordinates system by the use of the first function including said calculated parameter, and moving said substrate on the basis of said calculated coordinates position to thereby form the latent image of a particular mark of said mask on each of said plurality of particular areas; and

the third step of measuring the coordinates position of each of said plurality of latent images on said stationary coordinates system, and transferring the pattern of said mask to each of said plurality of areas by the utilization of said plurality of coordinates positions.

3. A method according to claim 2, wherein said third step includes the step of statistically calculating said plurality of coordinates positions to thereby calculate the parameter of a second function corresponding to the arrangement of said plurality of particular areas, and wherein the parameter of said second function is utilized for the transfer of the pattern of said mask to each of said plurality of areas.

4. A method according to claim 3, further comprising:

the step of correcting the parameter of said first function on the basis of the parameter of said second function, and calculating the coordinates position of each of said plurality of areas on said stationary coordinates system by the use of the first function including said corrected parameter; and

the step of moving said substrate on the basis of said calculated coordinates positions.

5. A method of exposing the image of the pattern of a mask onto a substrate by the use of a projection optical system, comprising:

the first step of disposing a mask having a particular mark on the object plane side of said projection optical system;

the second step of positioning said substrate at each of a plurality of positions in the direction of the optical axis of said projection optical system, and forming the latent image of said particular mark on said substrate;

the third step of applying illumination light to each of the plurality of latent images formed on said substrate, detecting the intensity of light generated from said latent images, and determining the best focus position of said projection optical system on the basis of said detected intensity of light; and

the fourth step of positioning said substrate at said best focus position and exposing the image of the pattern of said mask onto said substrate.

6. A method according to claim 5, wherein said second step includes the sub-step of moving said substrate in a direction perpendicular to the optical axis of said projection optical system each time the latent image of said particular mark is formed on said substrate.

7. A method according to claim 5, wherein at said second step, the latent image of said particular mark is formed in other area on said substrate than the area on which the image of the pattern of said mask is exposed.

8. A method according to claim 5, wherein said particular mark is a diffraction grating mark and at said second step, a position in the direction of said optical axis at which the intensity of diffracted light generated from said diffraction grating mark becomes maximum or minimum is determined as the best focus position.

9. A method of measuring the focus position of a projection optical system, comprising:

the step of disposing a first substrate having a particular mark on the object plane side of said projection optical system;

the step of positioning a photosensitive second substrate at each of a plurality of positions in the direction of the optical axis of said projection optical system, and forming the latent image of said particular mark on said second substrate; and

the step of applying illumination light to each of the plurality of latent images formed on said second substrate, and determining the focus position of said projection optical system on the basis of the intensity of light generated from said latent images.

10. A method for performing an alignment of an image of a pattern on a mask with each of a plurality of areas, on a photosensitive substrate, which is exposed by the pattern image, the method comprising:

measuring at least three positions within said plurality of areas and performing a statistic treatment of those measured positions, so that parameters in a first model formula corresponding to an arrangement of said plurality of areas are obtained;

calculating, based on the first model formula, a position of each of a plurality of special areas on said photosensitive substrate and relatively moving the mask and the photosensitive substrate in response to the calculated positions to expose each of said plurality of special areas by an image of a mark on the mask, so that a latent image of the mark is formed at each of the plurality of special areas;

measuring a position of each of the plurality of latent images and performing a statistic treatment of the measured positions, so that parameters in a second model formula corresponding to an arrangement of the plurality of latent images are obtained, the parameters corresponding to deviations between the calculated positions and the measured positions in the special areas; and

performing an alignment of the pattern image with each of the plurality of areas based on the parameters in the second model formula.

11. A method according to claim 10, further comprising:

calculating a position of each of said plurality of areas based on parameters in said first and second model formulas and relatively moving said mask and said photosensitive substrate according to the calculated positions, so that an alignment of a pattern image of said mask with each of the plurality of areas is performed.

12. A method according to claim 10, further comprising:

setting the plurality of special areas at a peripheral area other than said plurality of areas on said photosensitive substrate.

13. A method for performing an alignment of an image of a pattern on a mask with each of a plurality of areas, on a photosensitive substrate, which is exposed by the pattern image, the method comprising:

measuring at least three positions within said plurality of areas and performing a statistic treatment of the measured positions, so that parameters in a first model formula corresponding to an arrangement of said plurality of areas are obtained;

calculating, based on the first model formula, a position of each of a plurality of special areas on said photosensitive substrate and relatively moving the mask and the photosensitive substrate in response to the calculated positions, so that a latent image of the mark on the mask is formed at each of said plurality of special areas;

measuring a position of each of the plurality of latent images and performing a statistic treatment of the measured positions, so that parameters in a second model formula corresponding to an arrangement of the plurality of latent images are obtained; and

correcting parameters in said first model formula according to parameters in said second model formula and performing an alignment of said pattern image with each of the plurality of areas based on the corrected parameters.

14. A method according to claim 13, further comprising:

calculating a position of each of said plurality of areas based on said corrected parameters, and relatively moving said mask and said photosensitive substrate according to the calculated positions, so that an alignment of the pattern image of the mask with each of said plurality of areas is performed.

15. A method for performing an alignment of an image of a pattern on a mask with each of a plurality of areas, on a photosensitive substrate, which is exposed by the pattern image, the method comprising:

measuring at least three positions within the plurality of areas and performing a statistic treatment of the measured positions, so that parameters in a model formula corresponding to an arrangement of the plurality of areas are obtained;

calculating a position of at least one special area on the photosensitive substrate based on the model formula and relatively moving the mask and the photosensitive substrate in response to the calculated position, so that a latent image of a mark on the mask is formed at least at one special area;

measuring a position of the latent image formed at least at said one special area to correct the parameters based on the measured position; and

performing an alignment of the pattern image with each of the plurality of areas based on the corrected parameters.

16. A method according to claim 15, further comprising:

calculating a position of each of the plurality of areas based on the corrected parameters and relatively moving said mask and said photosensitive substrate according to the calculated positions, so that an alignment of said pattern image of the mask with each of the plurality of areas is carried out.

17. A method for performing an alignment of an image of a pattern on a mask with each of a plurality of areas, on a photosensitive substrate, which is exposed by the pattern image, the method comprising:

measuring at least three positions within the plurality of areas and performing a statistic treatment of the measured positions, so that a position of at least one special area which is different from the plurality of areas is calculated;

relatively moving the mask and the photosensitive substrate according to the calculated position of said at least one special area, so that a latent image of a mark on the mask is formed at said at least one special area; and

measuring a position of the latent image formed at said at least one special area and performing an alignment of the pattern image with each of the plurality of areas based on a deviation between the measured position and the calculated position.