Surface position detecting apparatus and method

Claim 2

A surface position detecting apparatus, which projects an image of a predetermined measurement pattern obliquely onto a surface of a plate object to be detected, which converges reflected light from the detected surface to re-image the image of said measurement pattern, and which then performs position detection of the detected surface relative to a predetermined reference plane in accordance with a re-imaged position of the image of said measurement pattern, comprising: a light source; an irradiation optical system for irradiating light from said light source obliquely onto said reference plane; a pattern plate having said measurement pattern, said pattern plate being located on a predetermined first plane so that the image of said measurement pattern is formed on said reference plane by said irradiation optical system; a converging optical system for, in a state where the detected surface of said object to be detected is substantially coincident with said reference plane, converging light irradiated from said irradiation optical system and then reflected by the detected surface to re-image the image of said measurement pattern on a predetermined second plane; and detecting device for detecting said re-imaged position of the image of the measurement pattern on said second plane; wherein the image of said measurement pattern comprises a linear image extending in a predetermined direction; and wherein said pattern plate is disposed such that an angle α between a direction in which the line image of said measurement pattern on the detected surface is displaced when the detected surface is moved along a direction perpendicular to said reference plane, and a longitudinal direction of the line image of said measurement pattern is in the range of from greater than 0° to less than 90°.

Claim 3

A surface position detecting apparatus according to claim 1, wherein said angle α is in the range of 10° to 80°.

Claim 4

A surface position detecting apparatus according to claim 1, wherein said first plane and said reference plane satisfy the Scheimpflug condition with respect to a principal plane of said irradiation optical system and wherein said reference plane and second plane satisfy the Scheimpflug condition with respect to a principal plane of said converging optical system.

Claim 5

A surface position detecting apparatus according to claim 1, wherein said pattern plate is optically transparent and wherein said measurement pattern of said pattern plate is formed such that light-transmitting portions and light-shielding portions extending in a predetermined direction are alternately arranged.

Claim 6

A surface position detecting apparatus according to claim 1, wherein said pattern plate is not optically transparent and wherein said measurement pattern of said pattern plate is formed such that slits extending in a predetermined direction are arranged in parallel and at a constant pitch.

Claim 7

A surface position detecting apparatus according to claim 1, wherein said pattern plate is a phase-type reflection diffraction grating.

Claim 8

A surface position detecting apparatus according to claim 1, wherein said pattern plate is an amplitude-type reflection pattern plate and wherein said measurement pattern of said pattern plate is formed such that reflecting portions and non-reflecting portions extending in a predetermined direction are alternately arranged.

Claim 9

A surface position detecting apparatus according to claim 1, wherein said measurement pattern of the pattern plate is so formed as to illuminate only desired measurement points on said reference plane.

Claim 10

A surface position detecting apparatus according to claim 1, wherein said pattern plate is arranged as rotatable about a predetermined axis perpendicular to said first plane.

Claim 11

A surface position detecting apparatus according to claim 1, wherein said detecting device comprises a photoelectric detector, a light-receiving surface of which is located on said second plane, for producing a detection signal changing depending upon the re-imaged position of the image of the measurement pattern on said second plane.

Claim 12

A surface position detecting apparatus according to claim 1, wherein said detecting device comprises two-dimensional scanning image pickup device, an image pickup surface of which is located on said second plane.

Claim 13

A surface position detecting apparatus according to claim 11, wherein said two-dimensional scanning image pickup unit is a two-dimensional charge-coupled image pickup device.

Claim 14

A surface position detecting apparatus according to claim 11, wherein an angle between a scanning direction on said image pickup surface of said two-dimensional scanning image pickup unit and the longitudinal direction of the linear image of said measurement pattern re-imaged on said second plane is set in the range of from greater than 0° to less than 90°.

Claim 15

A surface position detecting apparatus according to claim 11, comprising: signal reading unit for reading image pickup signals of pixels within a predetermined region in said image pickup surface of said two-dimensional scanning image pickup unit; and adding unit for adding the image pickup signals from said signal reading unit as shifting the image pickup signals from each other in accordance with an angle between said longitudinal direction of the linear image and a displacement direction of the linear image of said measurement pattern re-imaged on said second plane when a surface position of the detected surface is changed.

Claim 16

A surface position detecting apparatus according to claim 1, wherein said detecting device comprises: a deflecting optical system disposed on said second plane, for deflecting a direction of an optical axis of said converging optical system; a relay optical system for forming on a predetermined third plane a further conjugate image of the image of the measurement pattern re-imaged on said second plane, using a beam deflected by said deflecting optical system; and a photoelectric detector a light-receiving surface of which is disposed on said third plane, for producing a detection signal changing according to a position of said conjugate image.

Claim 17

A surface position detecting apparatus according to claim 1, wherein said detecting device comprises: a deflecting optical system disposed on said second plane, for deflecting a direction of an optical axis of said converging optical system; a relay optical system for forming on a predetermined third plane a further conjugate image of the image of the measurement pattern re-imaged on said second plane, using a beam deflected by said deflecting optical system; and two-dimensional scanning image pickup unit an image pickup surface of which is located on said third plane.

Claim 18

A surface position detecting apparatus according to claim 16, wherein said two-dimensional scanning image pickup unit is a two-dimensional charge-coupled image pickup device.

Claim 19

A surface position detecting apparatus according to claim 16, wherein an angle between a scanning direction on said image pickup surface of said two-dimensional scanning image pickup unit and a longitudinal direction of the conjugate image on said third plane is in the range of from greater than 0° to less than 90°.

Claim 20

A surface position detecting apparatus according to claim 16, comprising: signal reading unit for reading image pickup signals of pixels within a predetermined region in said image pickup surface of said two-dimensional scanning image pickup unit; and adding means for adding image pickup signals from said signal reading unit as shifting the image pickup signals from each other in accordance with an angle between a longitudinal direction of said conjugate image and a displacement direction of the conjugate image on said third plane when a surface position of the detected surface is changed.

Claim 21

A surface position detecting apparatus according to claim 1, wherein if the detected object is a wafer, on a surface as the detected surface of which a pattern is formed, an angle between a direction of said pattern and a longitudinal direction of the image of the measurement pattern formed on the surface of wafer is in the range of from greater than 0° to less than 90°.

Claim 22

A surface position detecting apparatus according to claim 20, wherein a direction in which the linear image of said measurement pattern is displaced when the surface of said wafer moves along a direction perpendicular to said reference plane, is arranged as parallel or perpendicular to a direction of the pattern on the surface of said wafer.

Claim 23

A surface position detecting method, in which an image of a predetermined measurement pattern is obliquely projected through an irradiation optical system onto a surface of a plate object to be detected, and in which position detection of the detected surface is performed relative to a predetermined reference plane in accordance with a re-imaged position of the image of said measurement pattern re-imaged by converging reflected light from the detected surface: wherein the image of said measurement pattern comprises a linear image extending in a predetermined direction; and wherein an angle Φ between a direction in which the linear image of said measurement pattern on the detected surface is displaced when the detected surface moves along a direction perpendicular to said reference plane, and a longitudinal direction of the linear image of said measurement pattern, is in the range of from greater than 0° to less than 90°.

Claim 24

A surface position detecting method, in which an image of a predetermined measurement pattern is obliquely projected through an irradiation optical system onto a surface of a plate object to be detected, and in which position detection of the detected surface is performed relative to a predetermined reference plane in accordance with a re-imaged position of the image of said measurement pattern re-imaged by converging reflected light from the detected surface: wherein the image of said measurement pattern comprises a linear image extending in a predetermined direction; and wherein an angle Φ between a direction in which the linear image of said measurement pattern on the detected surface is displaced when the detected surface moves along a direction perpendicular to said reference plane, and a longitudinal direction of the linear image of said measurement pattern, is in the range of from greater than 0° to less than 90°.

Claim 25

A surface position detecting method according to claim 22, wherein if the detected object is a wafer, on a surface as the detected surface of which a pattern is formed, an angle between the direction of said pattern and the longitudinal direction of the linear image of the measurement pattern formed on the surface of wafer is in the range of from greater than 0° to less than 90°.

Claim 26

A surface position detecting method according to claim 23, wherein a direction in which the linear image of said measurement pattern on the surface is displaced when the surface of said wafer moves along a direction perpendicular to said reference plane is arranged as parallel or perpendicular to the direction of the pattern on the surface of said wafer.

Claim 27

A projection type exposure apparatus comprising: a projection optical system for projecting a pattern formed on a mask, onto a photosensitive substrate; support unit for supporting the substrate, said support unit being arranged to adjust a position of the substrate in a direction parallel to a first optical axis of said projection optical system, a position of the substrate in two directions normal to said first optical axis and perpendicular to each other, and an inclination of the substrate relative to a plane which is perpendicular to said first optical axis; a surface position detecting device for detecting a position of a surface of the substrate supported by said support unit; and control unit for controlling said support unit such that the surface of the substrate supported by said support unit is substantially coincident with a focus plane of said projection optical system, based on a result of detection by said surface position detecting device; wherein said surface position detecting device, which projects an image of a predetermined measurement pattern obliquely onto the substrate surface, which converges reflected light from the substrate surface to re-image the image of said measurement pattern, and which then performs position detection of the substrate surface relative to said focus plane of said projection optical system in accordance with a re-imaged position of the image of said measurement pattern, includes: a light source; an irradiation optical system for irradiating light from said light source obliquely onto said focus plane; a pattern plate having said measurement pattern, said pattern plate being located on a predetermined first plane so that the image of said measurement pattern is formed on said focus plane by said irradiation optical system; a converging optical system for, in a state where the detected substrate surface is substantially coincident with said reference plane, converging light irradiated from said irradiation optical system and then reflected by the detected substrate surface to re-image the image of said measurement pattern on a predetermined second plane; and detecting device for detecting said re-imaged position of the image of the measurement pattern on said second plane; wherein the image of said measurement pattern comprises a linear image extending in a predetermined direction; and wherein said pattern plate is disposed such that an angle α between a direction in which the line image of said measurement pattern on the detected substrate surface is displaced when the detected substrate surface is moved along said first optical axis of said projection optical system, and a longitudinal direction of the line image of said measurement pattern is in the range of from greater than 0° to less than 90°.

Claim 28

A projection type exposure apparatus comprising: a projection optical system for projecting a pattern formed on a mask, onto a photosensitive substrate; support unit for supporting the substrate, said support unit being arranged to adjust a position of the substrate in a direction parallel to a first optical axis of said projection optical system, a position of the substrate in two directions normal to said first optical axis and perpendicular to each other, and an inclination of the substrate relative to a plane which is perpendicular to said first optical axis; a surface position detecting device for detecting a position of a surface of the substrate supported by said support unit; and control unit for controlling said support unit such that the surface of the substrate supported by said support unit is substantially coincident with a focus plane of said projection optical system, based on a result of detection by said surface position detecting device; wherein said surface position detecting device, which projects an image of a predetermined measurement pattern obliquely onto the substrate surface, which converges reflected light from the substrate surface to re-image the image of said measurement pattern, and which then performs position detection of the substrate surface relative to said focus plane of said projection optical system in accordance with a re-imaged position of the image of said measurement pattern, includes: a light source; an irradiation optical system for irradiating light from said light source obliquely onto said focus plane; a pattern plate having said measurement pattern, said pattern plate being located on a predetermined first plane so that the image of said measurement pattern is formed on said focus plane by said irradiation optical system; a converging optical system for, in a state where the detected substrate surface is substantially coincident with said reference plane, converging light irradiated from said irradiation optical system and then reflected by the detected substrate surface to re-image the image of said measurement pattern on a predetermined second plane; and detecting device for detecting said re-imaged position of the image of the measurement pattern on said second plane; wherein the image of said measurement pattern comprises a linear image extending in a predetermined direction; and wherein said pattern plate is disposed such that an angle α between a direction in which the line image of said measurement pattern on the detected substrate surface is displaced when the detected substrate surface is moved along said first optical axis of said projection optical system, and a longitudinal direction of the line image of said measurement pattern is in the range of from greater than 0° to less than 90°.

Claim 29

A projection type exposure apparatus according to claim 25, wherein said angle α is in the range of 10° to 80°.

Claim 30

A projection type exposure apparatus according to claim 25, wherein said first plane and said reference plane satisfy the Scheimpflug condition with respect to a principal plane of said irradiation optical system and wherein said reference plane and second plane satisfy the Scheimpflug condition with respect to a principal plane of said converging optical system.

Claim 31

A projection type exposure apparatus according to claim 25, wherein said pattern plate is optically transparent and wherein said measurement pattern of said pattern plate is formed such that light-transmitting portions and light-shielding portions extending in a predetermined direction are alternately arranged.

Claim 32

A projection type exposure apparatus according to claim 25, wherein said pattern plate is not optically transparent and wherein said measurement pattern of said pattern plate is formed such that slits extending in a predetermined direction are arranged in parallel and at a constant pitch.

Claim 33

A projection type exposure apparatus according to claim 25, wherein said pattern plate is a phase-type reflection diffraction grating.

Claim 34

A projection type exposure apparatus according to claim 25, wherein said pattern plate is an amplitude-type reflection pattern plate and wherein said measurement pattern of said pattern plate is formed such that reflecting portions and non-reflecting portions extending in a predetermined direction are alternately arranged.

Claim 35

A projection type exposure apparatus according to claim 25, wherein said measurement pattern of the pattern plate is so formed as to illuminate only desired measurement points on said focus plane.

Claim 36

A projection type exposure apparatus according to claim 25, wherein said pattern plate is arranged as rotatable about a predetermined axis perpendicular to said first plane.

Claim 37

A projection type exposure apparatus according to claim 25, wherein said detecting device comprises a photoelectric detector, a light-receiving surface of which is located on said second plane, for producing a detection signal changing depending upon the re-imaged position of the image of the measurement pattern on said second plane.

Claim 38

A projection type exposure apparatus according to claim 25, wherein said detecting device comprises two-dimensional scanning image pickup unit, an image pickup surface of which is located on said second plane.

Claim 39

A projection type exposure apparatus according to claim 35, wherein said two-dimensional scanning image pickup unit is a two-dimensional charge-coupled image pickup device.

Claim 40

A projection type exposure apparatus according to claim 35, wherein an angle between a scanning direction on said image pickup surface of said two-dimensional scanning image pickup unit and the longitudinal direction of the linear image of said measurement pattern re-imaged on said second plane is set in the range of from greater than 0° to less than 90°.

Claim 41

A projection type exposure apparatus according to claim 35, comprising: signal reading unit for reading image pickup signals of pixels within a predetermined region in said image pickup surface of said two-dimensional scanning image pickup unit; and adding unit for adding the image pickup signals from said signal reading unit as shifting the image pickup signals from each other in accordance with an angle between said longitudinal direction of the linear image and a displacement direction of the linear image of said measurement pattern re-imaged on said second plane when a surface position of the detected substrate surface is changed.

Claim 42

A projection type exposure apparatus according to claim 25, wherein said detecting unit comprises: a deflecting optical system disposed on said second plane, for deflecting a direction of an optical axis of said converging optical system; a relay optical system for forming on a predetermined third plane a further conjugate image of the image of the measurement pattern re-imaged on said second plane, using a beam deflected by said deflecting optical system; and a photoelectric detector a light-receiving surface of which is disposed on said third plane, for producing a detection signal changing according to a position of said conjugate image.

Claim 43

A projection type exposure apparatus according to claim 25, wherein said detecting device comprises: a deflecting optical system disposed on said second plane, for deflecting a direction of an optical axis of said converging optical system; a relay optical system for forming on a predetermined third plane a further conjugate image of the image of the measurement pattern re-imaged on said second plane, using a beam deflected by said deflecting optical system; and two-dimensional scanning image pickup unit an image pickup surface of which is located on said third plane.

Claim 44

A projection type exposure apparatus according to claim 40, wherein said two-dimensional scanning image pickup unit is a two-dimensional charge-coupled image pickup device.

Claim 45

A projection type exposure apparatus according to claim 40, wherein an angle between a scanning direction on said image pickup surface of said two-dimensional scanning image pickup unit and a longitudinal direction of the conjugate image on said third plane is in the range of from greater than 0° to less than 90°.

Claim 46

A projection type exposure apparatus according to claim 40, comprising: signal reading unit for reading image pickup signals of pixels within a predetermined region in said image pickup surface of said two-dimensional scanning image pickup unit; and adding unit for adding image pickup signals from said signal reading unit as shifting the image pickup signals from each other in accordance with an angle between a longitudinal direction of said conjugate image and a displacement direction of the conjugate image on said third plane when a surface position of the detected substrate surface is changed.

Claim 47

A projection type exposure apparatus according to claim 25, wherein if the substrate is a wafer, on a surface as the detected surface of which a pattern is formed, an angle between a direction of said pattern and a longitudinal direction of the image of the measurement pattern formed on the surface of wafer is in the range of from greater than 0° to less than 90°.

Claim 48

A projection type exposure apparatus according to claim 44, wherein a direction in which the linear image of said measurement pattern is displaced when the surface of said wafer moves along said first optical axis, is arranged as parallel or perpendicular to a direction of the pattern on the surface of said wafer.

Claim 49

A surface position detecting apparatus comprising: an irradiation optical system for irradiating light obliquely onto a reference plane; a pattern plate having a measurement pattern and located on a predetermined first plane to form the image of said measurement pattern on said reference plane by said irradiation optical system; a converging optical system for converging light irradiated from said irradiation optical system and then reflected by a surface of a plate object to be detected to re-image the image of said measurement pattern on a predetermined second plane; and detecting device for detecting said re-imaged position of the image of the measurement pattern on said second plane, wherein the image of the measurement pattern comprises a linear image extending in a predetermined direction and wherein an angle between a direction in which the linear image is displaced when the surface is moved perpendicular to a reference plane and a longitudinal direction of the linear image is in the range of from greater than 0 to less than 90 degrees.

Claim 50

A surface position detecting apparatus comprising: an irradiation optical system for irradiating light obliquely onto a reference plane; a pattern plate having a measurement pattern and located on a predetermined first plane to form the image of said measurement pattern on said reference plane by said irradiation optical system; a converging optical system for converging light irradiated from said irradiation optical system and then reflected by a surface of a plate object to be detected to re-image the image of said measurement pattern on a predetermined second plane; and detecting device for detecting said re-imaged position of the image of the measurement pattern on said second plane, wherein the image of the measurement pattern comprises a linear image extending in a predetermined direction and wherein an angle between a direction in which the linear image is displaced when the surface is moved perpendicular to a reference plane and a longitudinal direction of the linear image is in the range of from greater than 0 to less than 90 degrees.

Claim 51

A projection type exposure apparatus comprising: a projection optical system for projecting a pattern formed on a mask, onto a photosensitive substrate; support unit for supporting the substrate, said support unit being arranged to adjust a position of the substrate in a direction parallel to a first optical axis of said projection optical system, a position of the substrate in two directions normal to said first optical axis and perpendicular to each other, and an inclination of the substrate relative to a plane which is perpendicular to said first optical axis; a surface position detecting device for detecting a position of a surface of the substrate supported by said support unit; and control unit for controlling said support unit such that the surface of the substrate supported by said support unit is substantially coincident with a focus plane of said projection optical system, based on a result of detection by said surface position detecting device; wherein said surface position detecting device comprises an irradiation optical system for irradiating light obliquely onto a reference plane; a pattern plate having a measurement pattern and located on a predetermined first plane to form the image of said measurement pattern on said reference plane by said irradiation optical system; a converging optical system for converging light irradiated from said irradiation optical system and then reflected by a surface of a plate object to be detected to re-image the image of said measurement patter on a predetermined second plane; and detecting device for detecting said re-imaged position of the image of the measurement pattern on said second plane, wherein the image of the measurement pattern comprises a linear image extending in a predetermined direction and wherein an angle between a direction in which the linear image is displaced when the surface is moved perpendicular to a reference plane and a longitudinal direction of the linear image is in the range of from greater than 0 to less than 90 degrees.

Claim 52

A projection type exposure apparatus comprising: a projection optical system for projecting a pattern formed on a mask, onto a photosensitive substrate; support unit for supporting the substrate, said support unit being arranged to adjust a position of the substrate in a direction parallel to a first optical axis of said projection optical system, a position of the substrate in two directions normal to said first optical axis and perpendicular to each other, and an inclination of the substrate relative to a plane which is perpendicular to said first optical axis; a surface position detecting device for detecting a position of a surface of the substrate supported by said support unit; and control unit for controlling said support unit such that the surface of the substrate supported by said support unit is substantially coincident with a focus plane of said projection optical system, based on a result of detection by said surface position detecting device; wherein said surface position detecting device comprises an irradiation optical system for irradiating light obliquely onto a reference plane; a pattern plate having a measurement pattern and located on a predetermined first plane to form the image of said measurement pattern on said reference plane by said irradiation optical system; a converging optical system for converging light irradiated from said irradiation optical system and then reflected by a surface of a plate object to be detected to re-image the image of said measurement patter on a predetermined second plane; and detecting device for detecting said re-imaged position of the image of the measurement pattern on said second plane, wherein the image of the measurement pattern comprises a linear image extending in a predetermined direction and wherein an angle between a direction in which the linear image is displaced when the surface is moved perpendicular to a reference plane and a longitudinal direction of the linear image is in the range of from greater than 0 to less than 90 degrees.