Apparatus for detecting an in-focus position of a substrate surface having a movable light intercepting member and a thickness detector
AssigneeNikon Corporation
InventorYasuo Yonezawa
Life of this patent
Estimating the term…
Abstract
A position detecting apparatus detects a matching state of a position of a surface of a light-transmissive object with respect to a fiducial object plane of an objective optical system. Light transmitted through one-half of a pupil plane of the objective optical system is reflected by a front surface of the object through an opposite half of the pupil plane to a photoelectric detector. Light reflected from a rear surface of the object through the opposite half of the pupil plane is intercepted and prevented from reaching the detector.
Claims16
A position detecting apparatus for detecting a matching state of a position of a light-transmissive object with respect to a fiducial object plane of an objective optical system, said apparatus comprising:
- an illumination system for projecting light to said object through a first part of said objective optical system at one side of a plane including an optical axis of said objective optical system;
- a detector for photoelectrically detecting light reflected from a front surface of said object through a second part of said objective optical system at an opposite side of said plane;
- and
- a light intercepting member movable along the optical axis of said objective optical system on a light path between said objective optical system and said detector, for preventing light reflected from a rear surface of said object, through said second part, from reaching said detector.
A position detecting apparatus for detecting a matching state of a position of a surface of an object with respect to a fiducial object plane of an objective optical system, said apparatus comprising:
- a projection system for projecting a predetermined pattern on a front surface of said object through a first part of said objective optical system at one side of a plane including an optical axis of said objective optical system;
- a detector for photoelectrically detecting an image of said pattern reflected from said front surface of said object through a second part of said objective optical system at an opposite side of said plane;
- a light intercepting member, disposed on a light path between said objective optical system and said detector, for preventing light reflected from a rear surface of said object through said second part, from reaching said detector;
- and
- an auxiliary optical system, disposed on a light path between said objective optical system and said detector, for varying a magnification of said pattern image formed on a light receiving surface of said detector.
A position detecting apparatus for detecting a matching state of a position of a surface of an object with respect to a fiducial object plane of an objective optical system, said apparatus comprising:
- a projection system for projecting a predetermined pattern on said surface of said object through a first part of said objective optical system at one side of a plane including an optical axis of said objective optical system;
- a detector for photoelectrically detecting an image of said pattern reflected from said surface of said object through a second part of said objective optical system at an opposite side of said plane;
- and
- an auxiliary optical system, disposed on a light path between said objective optical system and said detector, for varying a magnification of said pattern image formed on a light receiving surface of said detector.
A position detecting apparatus for detecting a matching state of a position of a light-transmissive object with respect to a fiducial object plane of an objective optical system, said apparatus comprising:
- an illumination system for projecting light to said object through a first part of said objective optical system at one side of a plane including an optical axis of said objective optical system;
- a detector for photoelectrically detecting light reflected from a front surface of said object through a second part of said objective optical system at an opposite side of said plane;
- and
- a light intercepting member disposed on a light path between said objective optical system and said detector for preventing light reflected from a rear surface of said object, through said second part, from reaching said detector;
- wherein said light intercepting member is disposed between a first position conjugate to said front surface of said object when said front surface of said object is located flush with said fiducial object plane of said objective optical system and a second position conjugate to said rear surface of said object when said front surface of said object is located flush with said fiducial object plane of said objective optical system, and
- said light intercepting member has a shielding portion for shielding only one side of said plane including the optical axis of said objective optical system.
A position detecting apparatus for detecting a matching state of a position of a light-transmissive object with respect to a fiducial object plane of an objective optical system, said apparatus comprising:
- an illumination system for projecting light to said object through a first part of said objective optical system at one side of a plane including an optical axis of said objective optical system;
- a detector for photoelectrically detecting light reflected from a front surface of said object through a second part of said objective optical system at an opposite side of said plane;
- a light intercepting member disposed on a light path between said objective optical system and said detector for preventing light reflected from a rear surface of said object, through said second part, from reaching said detector;
- and
- a relay optical system for converging, on a light receiving surface of said detector, said reflected light from said front surface of said object which is converged on a predetermined position through said objective optical system;
- wherein said light intercepting member is disposed between a first position conjugate to said front surface of said object when said front surface of said object is located flush with said fiducial object plane of said objective optical system and a second position conjugate to said rear surface of said object when said front surface of said object is located flush with said fiducial object plane of said objective optical system, and
- said light intercepting member has a shielding portion for shielding only one side of said plane including the optical axis of said objective optical system.
Dependencies are inferred from the claim text.