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US 5,424,552 AGranted
Projection exposing apparatus
AssigneeNikon Corporation
InventorsToshihiko Tsuji, Tetsuo Taniguchi, Yuji Imai, Mizutani Hideo
Life of this patent
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Abstract
A projection exposing apparatus for detecting a state of focus at two or more places in exposure region of a projection optical system by a focus state detection device. In accordance with the result of the detection of the focus state at the two or more places, the image forming characteristics of the projection optical system are measured by an image forming characteristics measuring device. A first pattern extending in the sagittal direction and a second pattern extending in the meridional direction are formed so that the focus state is measured by light beams transmitted these patterns and therefore the astigmatism, eccentricity or the spherical aberration is obtained so as to be corrected.
Claims32
A projection exposing apparatus for projecting and exposing a pattern formed on a pattern surface of a mask to the surface of photosensitive substrate through a projection optical system, said projection exposing apparatus comprising:
- first illumination means for irradiating said mask with exposing light;
- stage means for holding said photosensitive substrate and capable of moving said photosensitive substrate in a direction of the optical axis of said projection optical system and in a direction perpendicular to said direction of said optical axis of said projection optical axis;
- a reference member disposed on said stage means and adapted to be arranged on the basis of a position conjugate to the surface of said mask pattern with respect to said projection optical system;
- two or more light transmissible patterns formed on the surface of said reference member;
- second illumination means for irradiating said light transmissible pattern from said stage means side with said exposing light or light having a wavelength substantially same as that of said exposing light and causing light transmitted through a plurality of said light transmissible patterns to be incident on said mask through said projection optical system;
- photoelectric detection means for receiving light emitted from said second illumination means, reflected by said mask, and again transmitted through said two or more light transmissible patterns through said projection optical system so as to transmit a photoelectric signal which corresponds to each quantity of received light;
- focus state detection means for detecting a focus state at each position of said two or more light transmissible pattern in response to said photoelectric signal transmitted from said photoelectric detection means when said stage means is moved in said direction of said optical axis of said projection optical system;
- and
- image forming characteristic measuring means for measuring image forming characteristics of said projection optical system in accordance with each result of the detections of the focus state detected by said focus state detection means.
6 more elements
A projection exposing apparatus for projecting and exposing a pattern formed on a pattern surface of a mask to the surface of a photosensitive substrate through a projection optical system, said projection exposing apparatus comprising:
- first illumination means for irradiating said mask with exposing light;
- stage means for holding said photosensitive substrate and capable of moving said photosensitive substrate in a direction of the optical axis of said projection optical system and in a direction perpendicular to said direction of said optical axis of said projection optical system;
- a reference member disposed on said stage means and adapted to be arranged on the basis of a position conjugate to the surface of said mask pattern with respect to said projection optical system;
- a light transmissible pattern formed on the surface of said reference member and having a first lattice pattern having a periodicity in a sagittal direction and a second lattice pattern having a periodicity in a meridional direction in an exposure region of said projection optical system;
- second illumination means for irradiating said light transmissible pattern from said stage means side and causing light transmitted through said light transmissible pattern to be incident on said mask through said projection optical system;
- photoelectric detection means for receiving light emitted from said second illumination means and reflected by said mask through said projection optical system and said light transmissible pattern;
- focus state detection means for detecting a focus state in response to a photoelectric signal transmitted from said photoelectric detection means when said stage means is moved in said direction of said optical axis of said projection optical system;
- and
- image forming characteristic measuring means for detecting said focus state by said focus state detection means in accordance with illumination light which passes through said first lattice pattern and detects said focus state by said focus state detection means in accordance with illumination light which passes through said second lattice pattern so as to measure image forming characteristics of said projection optical system in accordance with results of detections of said two focus states.
6 more elements
A projection exposing apparatus for projecting and exposing a pattern formed on a pattern surface of a mask to the surface of a photosensitive substrate through a projection optical system, said projection exposing apparatus comprising:
- first illumination means for irradiating said mask with exposing light;
- stage means for holding said photosensitive substrate and capable of moving said photosensitive substrate in a direction of the optical axis of said projection optical system and in a direction perpendicular to said direction of said optical axis;
- a reference member disposed on said stage means and adapted to be arranged on the basis of a position conjugate to the surface of said mask pattern with respect to said projection optical system;
- a light transmissible pattern formed on the surface of said reference member;
- second illumination means for irradiating said light transmissible pattern from said stage means side and causing light transmitted through said light transmissible pattern to be incident on said mask through said projection optical system;
- photoelectric detection means for receiving light emitted from said second illumination means and reflected by said mask through said projection optical system and said light transmissible pattern;
- focus state detection means for detecting a focus state in response to a photoelectric signal transmitted from said photoelectric detection means when said stage means is moved in said direction of said optical axis of said projection optical system;
- and
- image forming characteristic measuring means for detecting said focus state by said focus state detection means at two or more positions in an exposure region of said projection optical system so as to measure the curvature of field of said projection optical system in accordance with the results of the detections of the focus state at said two or more positions.
6 more elements
A projection exposing apparatus for projecting and exposing a pattern formed on a mask to the surface of a photosensitive substrate with exposing light through a projection optical system, said projection exposing apparatus comprising:
- stage means for holding said photosensitive substrate and capable of moving said photosensitive substrate in a direction of the optical axis of said projection optical system and in a direction perpendicular to said direction of said optical axis;
- a reference member disposed on said stage means and adapted on the basis of a position conjugate to the surface of said mask pattern with respect to said projection optical system;
- a light transmissible pattern formed on the surface of said reference member;
- illumination means for irradiating said light transmissible pattern from said stage means side and causing light transmitted through said light transmissible pattern to be incident on said mask through said projection optical system;
- photoelectric detection means for receiving light emitted from said illumination means and reflected by said mask through said projection optical system and said light transmissible pattern;
- focus state detection means for detecting a focus state in response to a first detection signal transmitted from said photoelectric detection means when said stage means is moved in said direction of said optical axis of said projection optical system;
- focal point detection means for detecting a focal point in response to a second detection signal for changing in according to a position of said photosensitive substrate in said direction of said optical axis of said projection optical system;
- focusing means for positioning said stage means in said direction of said optical axis of said projection optical system so that said second detection signal has a predetermined false in-focus level;
- and
- calibration means for adjusting an offset of said second detection signal or the false in-focus level on the basis of said first detection signal obtained when said stage means is moved in said direction of said optical axis of said projection optical system.
7 more elements
A projection exposing apparatus for projecting and exposing a pattern formed on a mask to the surface of a photosensitive substrate with exposing light through a projection optical system, said projection exposing apparatus comprising:
- stage means for holding said photosensitive substrate and capable of moving said photosensitive substrate in a direction of the optical axis of said projection optical system and in a direction perpendicular to said direction of said optical axis;
- a reference member disposed on said stage means and adapted on the basis of a position conjugate to the surface of said mask pattern with respect to said projection optical system;
- a light transmissible pattern formed on the surface of said reference member;
- illumination means for irradiating said light transmissible pattern from said stage means side and causing light transmitted through said light transmissible pattern to be incident on said mask through said projection optical system;
- photoelectric detection means for receiving light emitted from said illumination means and reflected by said mask through said projection optical system and said light transmissible pattern, and outputting photoelectric signal according to the position of said stage in said direction of said optical axis;
- and
- aberration quantity detection means for obtaining the aberration quantity of said projection optical system in accordance with information about the waveform of said photoelectric signal.
4 more elements
Dependencies are inferred from the claim text.