公开(公告)号：JPH021512A

公开(公告)日：1990-01-05

申请号：JP3674089

申请日：1989-02-16

Applicant: CANON KK

Inventor： OWADA MITSUTOSHI ,  MATSUGI MASAKAZU ,  SUDA SHIGEYUKI ,  YOSHII MINORU ,  NIWA YUKICHI ,  NOSE TETSUSHI ,  SAITO KENJI

IPC: G01B11/14 ,  G03F9/00 ,  H01L21/027 ,  H01L21/30

Abstract: PURPOSE:To obtain a gap between a first object and a second object shaped like a plate by placing both the objects so as to be opposed to each other, deflecting a luminous flux which is projected by both of both the objects, and thereafter, detecting an incident position of the luminous flux on the surface of a light receiving means. CONSTITUTION:A luminous flux 1 from a semiconductor laser LD is made incident vertically on a point A on the surface of a first Fresnel zone plate 4 on the surface of a mask 2. A diffracted light is deflected, namely, reflected at point B (C) on the surface of a wafer 3. Reflected light 31 thereof is reflected light when the wafer 3 is positioned in a position P1 of an interval dO to the mask 2. Also, the reflected light 32 is an incident light when the wafer 3 is displaced by a distance dG from the position P1 and positioned in a position P2. Subsequently, the reflected light from the wafer 3 is made incident on a point D on the surface of the second FZP 5 on the surface of the first object 2. A diffracted light 61 which is diffracted at an angle theta2 from the FZP 5 is guided onto the surface of a photodetecting means 8 through a condensing lens 7. By detecting a position of the center of gravity of the incident luminous flux 61 in such a case, an interval between the mask 2 and the wafer 3 is calculated and obtained.

公开(公告)号：JPH01233305A

公开(公告)日：1989-09-19

申请号：JP6000788

申请日：1988-03-14

Applicant: CANON KK

Inventor： SAITO KENJI ,  MATSUGI MASAKAZU ,  NIWA YUKICHI ,  NOSE TETSUSHI ,  YOSHII MINORU ,  SUDA SHIGEYUKI

IPC: G01B11/00 ,  G03F9/00 ,  H01L21/027 ,  H01L21/30

Abstract: PURPOSE:To detect a difference between the quantities of light on prescribed surfaces with high precision and thereby to enable the highly precise implementation of alignment, by providing physico-optical elements on the surfaces of a first substance and a second substance respectively and by using these physico-optical elements. CONSTITUTION:A light flux from a light source 10 is turned to be a parallel light flux by a light-projecting lens 11, and a first physico-optical element 3a formed of a phase-type zone plate or the like and provided in a first substance 1 is thereby irradiated. The optical element 3a has a focusing function and focuses an emission on a point Q at a distance b1a therefrom. A light flux diverging from the point Q is made to fall on a second physico-optical element 4a provided in a second substance 2 which is disposed at a position located at a distance a2a from the point Q. The second physico-optical element 4a has the focusing function like the first physico-optical element 3a, and it focuses an emission on a detecting surface 9 of a detector 8. When there is a relative positional difference between the substances 1 and 2 on the occasion, a difference between barycenters of quantities of light takes place in accordance with the amount of the positional difference. By detecting this difference and adjusting it, the highly precise implementation of alignment is enabled.

公开(公告)号：JPH01150804A

公开(公告)日：1989-06-13

申请号：JP31029587

申请日：1987-12-07

Applicant: CANON KK

Inventor： SEKINE MASAYOSHI ,  YOSHII MINORU ,  MATSUGI MASAKAZU ,  NOSE TETSUSHI

IPC: G01J9/02 ,  G01B9/02 ,  G01B11/24 ,  G01D3/028 ,  G01J3/28 ,  G01M11/02

Abstract: PURPOSE:To efficiently eliminate a noise component multiplexed to an image of an interference fringe by executing the sampling in the direction being different from the sampling direction to be analyzed by using a space in which a long-term signal strength variation is arranged in a stripe shape and appears, as an object, based on information to be measured. CONSTITUTION:Information of a surface shape state of an object 3 to be measured is converted to an image of an interference fringe by a shearing interferometer 2, and inputted to a frame memory 6. This image is divided 36, a correlation of the sampling direction and space frequency band width is derived, and with regard to an area in which said relation is the strongest, a sampling direction 35 in which the band width becomes the narrowest is derived. In such a way, interference fringe image information of the area 36 is inputted to a variable memory space 9, and in this area, a two-dimensional high speed Fourier-transformation is applied, and a two-dimensional spectral space is derived. Also, a cut-off frequency is determined with respect to the sampling direction 35, and a frequency component being higher than said frequency is eliminated or attenuated. Subsequently, when the two-dimensional spectral space is brought to reverse Fourier transformation and an interference fringe is obtained, the noise is eliminated from this interference fringe.

公开(公告)号：JPS6461602A

公开(公告)日：1989-03-08

申请号：JP21878787

申请日：1987-08-31

Applicant: CANON KK

Inventor： MATSUGI MASAKAZU ,  HASEGAWA MASANORI ,  YOSHII MINORU

IPC: G01B11/24

Abstract: PURPOSE:To measure the shape of any surface with high accuracy by using different interference system devices selectively to measure the surface shape of a stationary body such as a plane and a sphere and the surface shape of a dynamic body such as an aspherical body and a vibrating body. CONSTITUTION:When the body 8 to be measured is a sphere or stationary body, a 1st shutter 14 is closed and a 2nd shutter 6 is open to take a measurement. Light from a light source 1 is split by a half-mirror 5 into reflected luminous flux and transmitted luminous flux; and the transmitted luminous flux is passed through a TS lens 7 and is made incident on the body 8 to be measured as a spherical wave and the reflected light becomes information light having a spherical aberration and is made incident again on the half-mirror 5. The reflected luminous flux, on the other hand, is made incident on and reflected by a plane mirror 4, incident on the half-mirror 5 again, and incident on an area sensor 16. The reflected light from the plane mirror 4 and information light are made to interfere with each other on the sensor 16 and form interference fringes, and a piezoelectric element displaces the plane mirror 4 in the optical-axis direction to measure the surface shape of the body 8 to be measured. The TS lens 7 is not necessary for the plane body 8 to be measured and a strobe light source is used to measure the dynamic body.

公开(公告)号：JPS63277926A

公开(公告)日：1988-11-15

申请号：JP11226687

申请日：1987-05-11

Applicant: CANON KK

Inventor： YOSHII MINORU ,  KURODA AKIRA ,  NOSE TETSUSHI ,  NIWA YUKICHI

IPC: G01B11/00 ,  G01D5/38 ,  H01L21/027 ,  H01L21/30 ,  H01L21/68

Abstract: PURPOSE:To improve the resolution and accuracy of length measurement by increasing the number of times of diffraction by a length measurement reference grating and constituting an optical system so that the quantity of light of a sensor varies plural numbers of times in the one-pitch movement of the reference grating. CONSTITUTION:Coherent light incident on the diffraction grating GS is diffracted as (+ or -)1st order light beams. When the diffraction grating GS moves by one pitch in an X direction, the (+)1st order diffracted light advances in phase by one wavelength and the (-)1st order diffracted light lags by one wavelength. Those refracted light beams are returned by corner cubes CP1 and CP2 and when it is diffracted again by the grating GS, said (+)1st order diffracted light further advances by one wavelength and the (-1)1st order diffracted light lags by one wavelength. When the diffraction grating moves by one pitch, the interference light has a light-shade change four number of times eventually. Then the outputs of photodetectors PD1 and PD2 are counted to measure the quantity of relative movement of the diffraction grating GS.

公开(公告)号：JPS63277925A

公开(公告)日：1988-11-15

申请号：JP11226587

申请日：1987-05-11

Applicant: CANON KK

Inventor： YOSHII MINORU ,  NOSE TETSUSHI ,  NIWA YUKICHI ,  KURODA AKIRA

IPC: G01B11/00 ,  G01D5/38 ,  H01L21/027 ,  H01L21/30 ,  H01L21/68

Abstract: PURPOSE:To make an optical system simple and compact by splitting coherent light from a light source into two by using a birefringent prism and making them incident on a diffraction grating which moves relatively. CONSTITUTION:The light emitted by the light source LD is made into a plane wave and then made incident vertically on the birefringent prism like a Wollaston prism WP. The light beams which are split by the Wollaston prism WP are diffracted by the diffraction grating GS which moves relatively and incident on photodetectors PD1 and PD2 through a lambda/4 plate QW, a polarization beam splitter BS, and polarizing plates PP1 and PP2. The outputs of the photodetectors PD1 and PD2 are counted to measure the quantity of relative movement of the diffraction grating GS.

公开(公告)号：JPS63277924A

公开(公告)日：1988-11-15

申请号：JP11226487

申请日：1987-05-11

Applicant: CANON KK

Inventor： KURODA AKIRA ,  YOSHII MINORU ,  NOSE TETSUSHI ,  NIWA YUKICHI

IPC: G01B11/00 ,  G01D5/38 ,  H01L21/027 ,  H01L21/30 ,  H01L21/68

Abstract: PURPOSE:To eliminate the need for assembly adjustments, to obtain tolerance to disturbance, and to constitute a small-sized, lightweight length measuring instrument with high accuracy by integrating principal parts except a diffraction grating as a reference scale on one substrate. CONSTITUTION:A length measurement optical system consists of a light source LD, a collimator lens CL, beam splitter HM1 and HM2, phase difference plates EP1 and EP2, corner cube prisms CC1 and CC2, a polarization beam splitter BS, photodetectors PD1 and PD2, an objective LN, an optical position detector PS, etc., which are integrated on one substrate. Light emitted by the light source LD passes through the length measurement optical system and diffraction grating GS and is detected by the photodetectors PD1 and PD2. The outputs of the photodetectors PD1 and PD2 are counted to measure the quantity of relative movement between the length measuring head MH and diffraction grating GS.

公开(公告)号：JPS63179224A

公开(公告)日：1988-07-23

申请号：JP1087287

申请日：1987-01-20

Applicant: CANON KK

Inventor： OKADA YOSHIMICHI ,  YOSHII MINORU ,  NIWA YUKICHI

IPC: G01B11/24 ,  G01B11/245 ,  G01J9/04 ,  G01N21/21

Abstract: PURPOSE:To measure the surface shape of a body to be measured, the uniformity of a medium, etc., with high accuracy by utilizing an optical heterodyne interference system, and moving the body to be measured and a light wave to be detected relatively and obtaining a beat signal to be detected. CONSTITUTION:Luminous flux emitted by a light source 2 is passed through a lambda/2 plate 3 and split by a polarization beam splitter (PBS) 4 into transmitted light and reflected light. Here, a 1st light wave which is diffracted by an acoustooptic (AO) element 6 and a 2nd light wave which is diffracted by an AO element 5 are superimposed by a PBS 15, passed through an image formation optical system 16 and a lambda/4 plate 17, and polarized reversely circularly to form interference fringes. The 1st and 2nd light waves are split by a PBS 18 into two, one light beam is image-formed on a detector 19, and the other is image-formed on a detector 20; and the respective detectors detect beat signals, which become a reference signal and a signal to be detected. Here, the reference signal of one measurement point obtained by the detector 19 is recorded 21 and the phase difference from the signal to be detected which is obtained by the detector 20 when a stage 24 is moved according to the reference signal is found.

公开(公告)号：JPS63127217A

公开(公告)日：1988-05-31

申请号：JP27298086

申请日：1986-11-18

Applicant: CANON KK

Inventor： BABA TAKESHI ,  YOSHII MINORU ,  NIWA YUKICHI

IPC: G02B7/36 ,  H04N5/232

Abstract: PURPOSE:To execute focusing at a high speed and with high accuracy to any object, irrespective of the brightness and the contrast, by calculating a non-focusing quantity from a ratio of detected high frequency components at the time of a different image forming state. CONSTITUTION:The intensity p(epsilon) of a high frequency component of an image of an object is detected through an image pickup element 2, a gate 3, a BPF 4, a detecting circuit 5, an A/D converter 6, etc., and stored in a register of a microprocessor 10, and the processor 10 calculates a high frequency component intensity ratio p(epsilon1)/p(epsilon2) based on an equation I which depends on only an image forming state of a different image forming state. Simultaneously, the processor 10 determines a difference DELTA of blur circle diameters epsilon1, epsilon2 of an optical system based on an equation II from a lens position and an F-number in each coupling state from a photographing optical system. Subsequently, from the equation I, II, the circle diameters epsilon1, epsilon2 are derived and a non-focusing quantity delta is calculated, based on an equation III, and while evaluating the non-focusing quantity delta, the focusing adjustment is executed at a high speed and with high accuracy to any object, irrespective of the brightness and the contrast. In the equation, M(kx, ky) denotes a known MTF function of the photographing optical system.

公开(公告)号：JPS62267713A

公开(公告)日：1987-11-20

申请号：JP11054486

申请日：1986-05-16

Applicant: CANON KK

Inventor： YOSHII MINORU ,  BABA TAKESHI ,  NIWA YUKICHI

IPC: H04N5/232 ,  G02B7/28 ,  G02B7/36 ,  G03B3/00 ,  G03B13/36

Abstract: PURPOSE:To prevent malfunctions in the lens driving direction in a state of severe out-of-focus, by judging the driving direction of a lens by using the degree of focusing of the outside of a distance measuring area. CONSTITUTION:A microcomputer 7 detects the degree of focusing PF in a distance measuring area in accordance with the output of a peak detecting circuit 61 and decides whether or not the degree of focusing PF is smaller than a prescribed lower-limit threshold q2. In a largely out-of-focus state, the computer 7 detects the degree of focusing PE of the outside of the distance measuring area in accordance with the output of another peak detecting circuit 62 and compares the detected values PF and PE with each other. When PE>PF, the microcomputer 7 moves a lens 1 in its extension direction through a driving circuit 8 and actuator 9. In cases other than PE>PF, the lens 1 is moved in its drawing-in direction. In the other state, the microcomputer 7 performs direction discrimination and drive by utilizing slight vibration of the lens.