JP2006010645A - Detector and stage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect the position and inclination of a stage that is moved precisely. <P>SOLUTION: A transmission type detector 22 comprises: a transparent body angle lattice 30 that is extended and formed in the travel direction of a first stage 14; a transparent substrate 32 for retaining the transparent body angle lattice 30 vertically; an emission section 34 for emitting a plurality of parallel light toward the transparent body angle lattice 30; and a light reception section 36 for receiving a plurality of parallel light transmitted through the transparent body angle lattice 30. Nine photodiodes are arranged at the light reception section 36, and detect the light reception intensity distribution of the plurality of parallel light transmitted through the transparent body angle lattice 30. Then, the position and inclination angle of the light reception section 34 to the transparent body angle lattice 30 at the fixed side can be detected from a change in the intensity distribution detected by the light reception section 36. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a detection apparatus and a stage apparatus, and more particularly to a detection apparatus and a stage apparatus that detect the state of a stage that is movable with high accuracy.

  In response to the high integration and low price of semiconductor devices that are the foundation of IT technology, there is an increasing demand for high productivity, high accuracy, high speed, and the like for semiconductor exposure apparatuses that manufacture semiconductor devices. A stage, which is a key component of a semiconductor exposure apparatus, requires a high-speed multi-degree-of-freedom stage apparatus having an accuracy of around 10 nm and a moving range of several hundred mm. Therefore, it is necessary to precisely measure the multi-degree-of-freedom position and orientation of the stage and feed back the result to control the positioning of the stage.

  As a position measuring method of a conventional positioning device, an optical linear encoder, a laser length measuring device, an autocollimator, or the like has been generally used. These are basically based on the one-dimensional length or posture measurement, and the position or posture is measured by a combination of a plurality of axes.

  Laser interferometers used for high-accuracy measurement measure the position of the stage (positioning object) using laser light, so measurement is based on air fluctuations in the device where the stage is placed. There was a problem that the accuracy of the value of was lowered. In addition, in a laser interferometer, optical components can be placed only outside (around) the stage, and it is necessary to mount a metal pipe serving as a laser optical path in each direction in order to prevent air fluctuations. Therefore, there is a problem that the entire stage apparatus becomes large and the configuration becomes complicated.

  Further, when the stage rotates about the Z axis, there is a problem that the reflected light from the stage is detached from the light receiving portion of the interferometer, and the position in the XY directions cannot be detected. As a detection device that solves such a problem, there is a detection device that irradiates a reference grating (angle grating) with laser light and detects reflected light reflected by the reference grating with a two-dimensional angle sensor in the XY directions. (For example, refer to Patent Document 1).

  FIG. 1 is a schematic diagram of a detection apparatus having a reference grating and a two-dimensional angle sensor. As shown in FIG. 1, the conventional detection apparatus 300 detects the position in the XY directions based on the output change of one two-dimensional angle sensor 290.

  Here, the two-dimensional angle sensor 290 detects the inclination of the surface of the reference grating, whereby the change in the normal direction of the surface of the reference grating can be seen, and the two-dimensional angle sensor 290 can detect the change in the XY direction. A tilt or normal change in (two directions) can be detected. The reference grating 320 is a collection of peaks and valleys that change with a known function in two orthogonal directions (X direction and Y direction) on a plane. The shape of the reference grating 320 includes a sine wave. Is used.

  Next, the two-dimensional angle sensor 290 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a diagram showing a two-dimensional angle sensor. The two-dimensional angle sensor 290 is a geometric optical sensor based on an autocollimation method.

As shown in FIG. 2, one laser beam 310 emitted from the laser light source 301 passes through the polarization beam splitter 302 and the quarter wavelength plate 303 and enters the surface of the reference grating 320. The laser beam 312 reflected by the surface of the reference grating 320 is reflected by the polarization beam splitter 302, and the laser beam 312 enters the autocollimator 305. The autocollimator 305 includes an objective lens 306 and a detector 307 that detects a spot position.
Japanese Patent No. 2960013

  However, in the above autocollimation method, a standard plate (generally a cross line) at the focal point of the objective lens 306 is imaged at infinity, and parallel light reflected by a plane mirror at the tip of the objective lens 306 is converted into a standard plate surface. In order to read the displacement at a minute angle of the plane mirror from the displacement in the plane of the imaged cross line, an expensive and complicated part such as the autocollimator 305 is required. There was a problem that the cost would be high.

  In addition, since high-resolution position detection is performed, the geometrical optical principle may not be established due to light interference and diffraction as the period between the reference grating 320 and the multi-spot becomes shorter. There was a problem that was difficult. Also, detection is performed for five degrees of freedom, ie, two-dimensional displacement (displacement in the X direction and Y direction) and three posture changes (rotation direction with respect to the X axis, rotation direction with respect to the Y axis, and rotation direction with respect to the Z axis). In order to do so, three two-dimensional angle sensors 300 are required, and there is a problem that adjustment between the sensors is difficult.

  Further, in the stage apparatus, for example, the pair of linear motors provided on both sides of the stage are driven and controlled while detecting the position when the stage is moved. It is necessary to accurately detect the movement amount and inclination of the linear motor by making 300 a more compact configuration.

  As a detection device other than the above, there is a linear scale that optically detects the number of slits by an optical sensor that moves with respect to a slit plate that is formed to extend in the moving direction of the stage, thereby detecting the position of the stage. Although this linear scale can detect the amount of displacement in the moving direction, it cannot detect other directions (for example, the vertical direction or the tilt angle around each axis of the stage).

  Therefore, in the conventional stage apparatus, a pair of linear scales are arranged on both sides of the stage, and the yawing angle of the stage is calculated from the difference between detection signals detected by the pair of linear scales. Then, the movement of the stage is controlled without detecting the tilt angle in the other direction of the stage.

  Therefore, in the conventional stage apparatus, since the linear motor is driven and controlled based on the position (movement amount) in the movement direction obtained from the linear scale, the state when moving the stage is not accurately grasped, When the stage was tilted, it was impossible to accurately detect in which direction and how much it was tilted.

  The present invention has been made in view of the above points, and it is possible to easily detect the displacement and the tilt angle of the stage and improve the detection accuracy by using a reference grid having a shape that is easy to manufacture. It is an object of the present invention to provide a detection device and a stage device that can perform the same.

  In order to solve the above problems, the present invention has the following features.

  The invention according to claim 1 is provided with a reference grating having a detection surface in which concave and convex curved surfaces having a predetermined radius of curvature are alternately formed in a two-dimensional direction on the surface, and movable relative to the reference grating. A light emitting unit that emits a plurality of parallel lights from a vertical direction of the reference grating toward the detection surface, and the plurality of parallel light beams that are provided so as to move integrally with the light emitting unit and that have passed through the reference grating. And a light receiving unit having a plurality of light receiving elements for receiving light.

  According to a second aspect of the present invention, there is provided a reference grating having a detection surface in which concave and convex surfaces having a predetermined radius of curvature are alternately formed in a two-dimensional direction on the surface, and a reflection formed on the back surface of the reference grating. A surface, a light emitting unit that is movable with respect to the reference grating and emits a plurality of parallel lights from a vertical direction of the reference grating toward the detection surface, and moves integrally with the light emitting unit And a light receiving unit having a plurality of light receiving elements that receive a plurality of parallel lights reflected from the reflecting surface.

  According to a third aspect of the present invention, there is provided a reference grating having a detection surface in which concave and convex surfaces having a predetermined radius of curvature are alternately formed in a two-dimensional direction on a surface, and a reflection surface formed on the detection surface; A light emitting unit that is movable with respect to the reference grating and emits a plurality of parallel lights from a vertical direction of the reference grating toward the detection surface, and is provided so as to move integrally with the light emitting unit. And a light receiving section having a plurality of light receiving elements for receiving a plurality of parallel lights reflected from the reflecting surface.

  According to a fourth aspect of the present invention, the light emitting unit includes a light source and a spectroscopic unit that splits light from the light source into a plurality of parallel lights.

  The invention according to claim 5 is characterized in that the spectroscopic means has an incident surface in which concave curved surfaces having a predetermined radius of curvature and convex curved surfaces are alternately formed in a two-dimensional direction.

  The invention according to claim 6 is characterized in that the light receiving section has a larger number of light receiving elements than the plurality of parallel lights, and at least one light receiving element is arranged for one light. To do.

  According to the seventh aspect of the present invention, a detection signal corresponding to the light intensity of the plurality of parallel lights received by the light receiving element is input, and the light emitting unit relative to the reference grating is changed from a change in each light intensity distribution. It has the calculating means which calculates a movement amount, It is characterized by the above-mentioned.

  According to an eighth aspect of the present invention, the calculating means is configured to make the light emitting unit and the light receiving unit relative to the detection surface based on a change in light intensity distribution of the plurality of parallel lights received by the plurality of light receiving elements. The tilt angle is calculated.

  The invention according to claim 9 is characterized in that the reference lattice is oriented at 180 degrees with respect to the transparent substrate, the first reference lattice provided on the front side of the transparent substrate, and the first reference lattice. And a second reference grating provided on the back side of the transparent substrate.

  According to a tenth aspect of the present invention, there is provided a base, a stage movably provided with respect to the base, a driving means for applying a driving force to the stage, and the movement of the stage. And a control means for controlling the drive means so that the stage moves at a predetermined speed in accordance with a detection result of the detection apparatus.

  The invention according to claim 11 is characterized in that the driving means is a pair of linear motors, and the control means drives the pair of linear motors in translation.

  A twelfth aspect of the invention is characterized in that the detection device according to any one of the first to ninth aspects is provided in the vicinity of the linear motor.

  According to the present invention, since the reference grating is arranged between one light emitting unit and the light receiving unit, the configuration can be simplified and compact, and the light emitting unit with respect to the reference grating, With respect to the relative position of the light receiving unit, it is possible to accurately detect the two directions corresponding to the detection surface of the reference grating and the inclination angle in each direction with respect to the reference grating from the change in the received light intensity distribution of a plurality of parallel lights. In addition, since the light emitting unit and the light receiving unit are configured to face the reflecting surface of the reference grating and receive a plurality of parallel lights reflected from the reflecting surface, the configuration can be simplified and made compact, and The relative positions of the light emitting unit and the light receiving unit with respect to the reference grating can be accurately detected in two directions corresponding to the detection surface of the reference grating and the inclination angle in each direction with respect to the reference grating from the change in the received light intensity distribution of a plurality of parallel lights. .

  Further, in the stage apparatus using the detection apparatus of the present invention, the stage is moved by a light emitting unit that emits a plurality of parallel lights and a light receiving unit that receives a plurality of parallel lights transmitted or reflected by the reference grating. It is possible to accurately detect the position of the stage in two directions corresponding to the detection surface of the stage, simultaneously detect the tilt angle of the stage in each direction, and control the stage to correct the tilt of the stage. become.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a conceptual diagram showing the main components of a stage apparatus to which the first embodiment of the detection apparatus according to the present invention is applied. In this embodiment, for convenience in explaining the configuration and operating principle of a transmission type detection device 22 to be described later, the direction in which light is applied to the transparent body angle grating 30 is hereinafter referred to as the Z direction. Will be described with the left-right direction as the Z direction.
As shown in FIG. 3, the stage apparatus 10 is provided with a base 12, a first stage 14 provided so as to be movable with respect to the base 12, and mounted on the first stage 14 so as to be movable in the left-right direction. The second stage 16, a pair of linear motors (drive means) 18, 20 that translate and drive both ends of the first stage 14, a transmission type detection device 22 disposed in the vicinity of the linear motor 18, and the second stage 16 The linear motor 24 to drive and the linear scale 26 arrange | positioned in parallel with the linear motor 24 are provided.

  The transmission type detection device 22 constitutes a main part of the present invention, and has a moving position of the first stage 14 as a main detection target as will be described later, and a motion error factor for directions other than the moving direction (X direction). The vertical direction (Y direction) and the angles θx, θy, θz around each axis can be detected simultaneously.

  The detection signals detected by the transmission type detection device 22 and the X linear scale 26 are coordinate-converted by a coordinate converter 27 and input to the control device 28. The control device 28 has calculation means (control program) that calculates control amounts that are set in advance and are supplied to the linear motors 18, 20, and 24 based on calculation formulas. Output to amplifiers 29a-29c. The drive signals amplified by the servo amplifiers 29a to 29c are supplied to the linear motors 18, 20, and 24, and the linear motors 18, 20, and 24 are driven.

  Further, the transmission type detection device 22 can detect the displacement of the first stage 14 in the X and Y directions and the tilt angle in the θz direction, as will be described later. Therefore, in the control device 28, the linear motors 18 and 20 can be translated and translated with high accuracy so that the first stage 14 does not tilt based on the detection data in each direction detected by the transmission type detection device 22. .

Here, the configuration of the transmission type detection device 22 used as the transmission type surface encoder will be described with reference to FIG.
As shown in FIG. 4, the transmission-type detection device 22 holds the transparent body angle grating (reference grating) 30 extending in the moving direction of the first stage 14 and the transparent body angle grating 30 in a vertical state. It has a transparent substrate 32, a light emitting section 34 that emits a plurality of parallel lights toward the transparent body angle grating 30, and a light receiving section 36 that receives the plurality of parallel lights that have passed through the transparent body angle grating 30.

  The transparent substrate 32 is made of a transparent glass plate or the like, and is fixed to the base 12 on the fixed side in a vertical state. A transparent angle grating 30 is fixed to the surface of the transparent substrate 32. Since the transparent body angle grating 30 and the transparent substrate 32 are formed of a transparent material, the transparent body angle grating 30 and the transparent substrate 32 have a property of transmitting light emitted from the light emitting unit 34.

  In addition, as shown in FIG. 5 in an enlarged manner, the transparent angle grating 30 has a three-dimensional concave curved surface and a convex curved surface alternately formed in a two-dimensional direction on the right side of a sinusoidal contour having a predetermined radius of curvature on the surface. The detection surface 30a thus formed is formed. With respect to the uneven shape of the detection surface 30a, for example, a fine concave curved surface and a convex curved surface can be formed uniformly and with high accuracy by pressing a mold.

  The light emitting unit 34 is provided so as to face the vertical direction of the surface of the transparent body angle grating 30. Further, the light receiving unit 36 is provided so as to face the vertical direction of the back surface of the transparent body angle grating 30. The light emitting unit 34 and the light receiving unit 36 are integrally supported by a bracket (not shown) fixed to the first stage 14 on the movable side, and through the transparent body angle grating 30 and the transparent substrate 32. Are held to face each other.

  Therefore, when the light emitting unit 34 and the light receiving unit 36 are driven in the Y direction together with the first stage 14, the light emitting unit 34 and the light receiving unit 36 move with respect to the transparent body angle grating 30 and the transparent substrate 32. At this time, a plurality of parallel lights emitted from the light emitting unit 34 are refracted and transmitted by the concave curved surface and the convex curved surface of the detection surface 30 a and received by the light receiving unit 36. As will be described later, the light receiving unit 36 is provided with a plurality of light receiving elements that receive a plurality of parallel lights from the light emitting unit 34 at predetermined intervals. Then, the refractive index changes depending on the position where the light from the light emitting unit 34 passes through the concave and convex curved surfaces of the detection surface 30 a, and the change in the received light intensity distribution of each light at the light receiving unit 36 causes the transparent angle grating 30 to It is possible to determine the amount of movement of the light emitting unit 34 and the light receiving unit 36.

FIG. 6 is a diagram showing the configuration of the transmission type detection device 22 in FIG. 4 as viewed from the X direction.
As shown in FIG. 6, the light emitting unit 34 divides the light from the light source 34 a made of, for example, a laser diode into a plurality of (for example, n = 9) parallel lights, and the light is emitted to the emission surface of the light source 34 a. A square spectroscopic plate 38 having a grid pattern as a spectroscopic means is attached.

FIG. 7 is an enlarged view showing an example of the grid pattern of the spectral plate 38. As shown in FIG. 7, the spectroscopic plate 38 has nine minute openings 38 </ b> A to 38 </ b> I formed in a lattice shape at a predetermined interval L _F on a two-dimensional plane in the X direction and the Y direction. The spectroscopic plate 38 is for splitting the light 40 emitted from the light source 34a into nine lights 42 _{1 to} 42 ₉ through the minute openings 38A to 38I.

  In FIG. 7, the configuration in which the spectroscopic plate 38 is provided with nine micro openings 38 </ b> A to 38 </ b> I has been described as an example. However, the number and interval of the micro openings can be arbitrarily set, for example, It is also possible to arrange 10 × 10 minute openings in the X direction and the Y direction. Accordingly, the number of light beams split by the spectroscopic plate 38 (in other words, the number of spots irradiated on the light receiving unit 36) can be set to an arbitrary number by selecting the number of micro apertures.

The minute openings 38A to 38I are formed to have the same size as the arrangement pitch F of the concave curved surface and the convex curved surface formed on the detection surface 30a. Further, since the nine lights 42 _{1 to} 42 ₉ that have passed through the minute openings 38A to 38I of the spectroscopic plate 38 become parallel light and are irradiated onto the detection surface 30a of the transparent body angle grating 30, the transparent body angle grating 30 is used. Multi-spots are generated at equal intervals with the arrangement pitch F of (or an interval that is an integral multiple of the arrangement pitch F by diffraction when passing through the openings 38A to 38I).

The nine lights 42 _{1 to} 42 _{9 that} have passed through the transparent angle grating 30 are condensed on the light receiving surface 36 a of the light receiving unit 36 by the objective lens 44 disposed immediately before the light receiving unit 36.

As shown in FIG. 8, photodiodes 51 to 59 that receive _nine lights 42 _{1 to} 42 ₉ transmitted through the transparent angle grating 30 are provided on the light receiving surface 36 a of the light receiving unit 36.

Next, the light receiving unit 36 will be described with reference to FIG. Circle shown by a broken line in FIG. 8 shows a multi-spot light ₄₂ 1-42 ₉ reaching the respective photodiodes 51-59. Photodiode 51 to 59 provided on the light receiving surface 36a of the light receiving portion 36 outputs a detection signal corresponding to the received light intensity of the light ₄₂ 1-42 _9. Of the photodiodes 51 to 59, the photodiodes 51, 53, 57, 59 arranged at the four corners of the light receiving surface 36a are made of a two-part PD combining a pair of light receiving elements, and are arranged at the center of the light receiving surface 36a. The diode 55 is composed of a quadrant PD in which four light receiving elements are combined.

2 divided PD51 arranged in the upper left of the light receiving surface 36a is a light receiving element (51a, 51b) formed in a triangular shape is a pair to detect the light intensity of the light 42 ₁ is disposed on the upper right corner two split PD53 detects the light intensity of the light 42 ₃ light receiving elements (53a, 53b) which is formed in a triangular shape becomes a pair, bisected PD57 arranged in the lower left corner is formed in a triangular shape light-receiving elements (57a, 57 b) detects the light intensity of the light 42 ₇ becomes a pair, the light receiving element divided into two PD59 arranged in the corners of the lower right, which is formed in a triangular shape (59a, 59b ) detects the light intensity of the light 42 ₉ become a pair.

Further, the four-divided PD 55 arranged at the center of the light receiving surface 36a is arranged in parallel so that four light receiving elements 55a to 55d are arranged in two rows in the X direction and the Y direction, and the four light receiving elements 55a. detecting the light intensity of the light 42 ₅ irradiated to the center by ～55D. Further, it disposed in the middle of the four sides of the light receiving surface 36a, the photodiode 52, 54, 56, 58 respectively light _{42 2,} 42 _4, 42 6, 42 for detecting the light intensity of _8. In this embodiment, the change in the intensity distribution of the light 42 _{1-42 9} detected by the light receiving unit 36 having the above-described nine photodiodes 51-59 performs position and inclination angle of the detection of the first stage 14.

Next, a simulation result of the transmission type detection device 22 will be described.
In the model using the transparent body angle grating 30, the surface shape of the detection surface 30a of the transparent body angle grating 30 is a concave curved surface and a convex curved surface in which sine waves are superimposed two-dimensionally as shown in Expression (1). .

Here, the pitches P _x and P _y of the transparent body angular grating shape are on the order of several hundred μm or less, and the amplitudes Ax and Ay are on the order of several hundred nm or less. When light is incident on this, it acts like a diffraction grating. Fulfill. Therefore, here, in setting up the model of the detection device 22, light is treated as a wave, and analysis is performed by calculating the amplitude and phase. That is, what is used here is not a geometric optics model but a wave optics model.

  As shown in FIG. 9, it is assumed that light enters the position (x, y) substantially perpendicularly from the vertical direction of the transparent body angle grating 30. At this time, when the light travels from the surface Σ1 to the surface Σ2, the light travels by the distance 2A-h (x, y), and then travels through the transparent angle grating 30 by the distance h (x, y) and travels through the transparent angle grating 30. To Penetrate. Assuming that the refractive index of the transparent angle grating 30 is n and the refractive index outside the transparent angle grating 30 is 1, the optical path length L when this light travels from the surface Σ1 to the surface Σ2 is expressed by the equation (2). Is done.

Since there is an optical path length of L when proceeding from the plane Σ1 to the plane Σ2, the phase is delayed by kL multiplied by the wave number k (= 2π / λ, λ: wavelength of light). Therefore, the phase function G (x, y) of the transparent body angle grating 30 can be expressed as the following equation (3).

When displacement in the X direction and Y direction and rotation about the Z axis occur in the transparent body angle lattice 30, Expression (4) can be expressed as the following Expression (5).

The above is the simulation result of the model of the transparent body angle lattice 30.

Next, the optical system of the transmission type detection device 22 using the transparent body angle grating 30 will be described.
As shown in FIG. 6, in the optical system of the transmission type detection device 22, the parallel lights 42 _{1 to} 42 ₉ emitted from the laser light source (LD) 34 a are applied to the lattice-shaped spectroscopic plate 38 having minute openings 38 </ b> A to 38 </ b> I. Incident. The lights diffracted by the minute apertures 38A to 38I of the spectroscopic plate 38 interfere with each other, and parallel light 42 _{1 to} 42 ₉ (multi-beam) having peaks at the same interval as the aperture interval of the grid pattern on the transparent body angle grating 30. Is generated. The parallel lights 42 _{1 to} 42 ₉ are transmitted through the transparent angle grating 30 and then collected by the objective lens 44 onto the light receiving surface 36 a of the light receiving unit 36.

  In order to obtain the intensity distribution on the light receiving surface 36a of the light receiving unit 36 of this optical system, here, the optical system is divided into elements, and functions that affect the amplitude term and phase term of the light wave of each element are used. , Based on them, we took a method of calculating in order of ua, ua ', ..., ud. The optical system includes a light emitting unit 34, a spectral plate 38, a transparent angle grating 30, an objective lens 44, and a light wave propagation space between elements.

  These functions are described below in order. The light emitting section 34 emits parallel light ua having an intensity of Gaussian distribution. That is, since the waves have the same phase in the same plane, the phase term is ignored, and the value obtained by taking the Gaussian route as the amplitude term is defined as the following equation (6).

The spectroscopic plate 38 transmits light incident on the micro openings 38A to 38I of the grid pattern, but blocks other light. Therefore, the transmission function g (x, y) can be expressed by the following equation (7).

The transparent body angle grating 30 is as described above.
Since the objective lens 44 has a function of converting a plane wave into a spherical wave, the phase function L (x, y) is expressed by the equation (8).

The propagation of light in space can be considered by the Fresnel diffraction equation. The light emitted from the surface Σ1 propagates to the surface Σ2 separated by the distance z. At this time, the formula of Fresnel diffraction can be expressed by the following formula (9).

Here, u ₀ (x ₀ , y ₀ ) is the wavefront at the plane Σ1, u (x, y) is the wavefront at the plane Σ2, i is the imaginary unit, and λ is the wavelength of light.

Equation (9) is a convolution integral and can be transformed into a form using Fourier transform as shown in Equation (10) below. Here, F [v (x, y)] represents the Fourier transform of v (x, y), and F ⁻¹ [ω (x, y)] represents the inverse Fourier transform of ω (x, y).

Based on the above, this model is summarized and the intensity distribution I (x, y) of the light receiving surface 36a of the light receiving unit 36 is obtained as follows.

Here, when the intensity distribution I (x, y) of the light receiving surface 36a of the light receiving unit 36 was simulated, the following results were obtained.

  FIG. 10 shows the result of calculating the intensity distribution I (x, y) according to the equation (11). The simulation conditions at this time are shown in Table 1. The calculation area was cut at regular intervals, and the mesh size at this time was 3 μm × 3 μm, and 1024 × 1024 points were taken on the XY plane.

As can be seen from this result, it can be seen that a large number of peaks are arranged at a constant period. As shown in FIG. 6, when light passes through the grid pattern (see FIG. 7) of the spectroscopic plate 38 and the transparent angle grating 30, the light is diffracted and interferes on the objective lens 44. This is because they are generated together.

First, the intensity change of each spot irradiated with the parallel lights 42 _{1 to} 42 ₉ when the displacement in the X direction occurs will be described.
A simulation of how the intensity distribution shown in FIG. 10 changes when the light 42 _{1 to} 42 ₉ from the light emitting unit 34 provided on the movable side with respect to the fixed-side transparent angle grating 30 is displaced in the X direction. The intensity distribution changed as shown in FIGS. 11 (A) to 11 (E). As can be seen from FIGS. 11A to 11E, the peak height distribution in the X direction changes. It can also be seen that the distribution in the Y direction has not changed.

Next, the intensity change of each spot when Y displacement occurs will be described.
When the light intensity distribution shown in FIG. 10 changes when the lights 42 _{1 to} 42 ₉ from the light emitting portion 34 are displaced in the Y direction with respect to the transparent body angle grating 30, the intensity distribution is shown in FIG. 12 (A) to (E). As shown in FIGS. 12A to 12E, it can be seen that the height distribution of the peak in the Y direction changes as in the case of displacement in the X direction. It can also be seen that the distribution in the X direction has not changed.

Next, the intensity change of each spot when the rotation in the _θZ direction occurs will be described.
Was examined on whether the simulation intensity distribution of light 42 _{1-42 9} shown in the Figure 10 when rotated to the theta _Z direction from the light emitting portion 34 is how the changes with respect to the transparent body angle grating 30, FIG. 13 ( It changed as shown in A) to (E). However, in this case, since almost no change in the spot is observed, FIGS. 14A to 14E are enlarged views of a part of the spots in FIGS. 13A to 13E. As shown in FIGS. 14A to 14E, when rotation in the θz direction occurs, the entire spot rotates in the same θ _Z direction with the peak at the center of the spot (here, the strongest peak) as an axis. I understand that

Here, a position detection method using the quadrant PD 55 will be described.
X direction with respect to the transparent body angle grating 30, the Y-direction of the displacement, the spot intensity of the light 42 _{1-42 9} was found to be the X direction, respectively, the height of the peak only in the Y direction changes. Utilizing this principle, these displacements can be detected by using the 4-part PD 55 shown in FIG. The detection principle and simulation results are shown below.

  As described above, the quadrant PD 55 is a combination of the four light receiving elements 55a to 55d in two rows in the X and Y directions, and is substantially the same as when four photodiodes are provided.

In FIG. 15, when the sensor outputs in the X and Y directions are S _X and S _Y , the outputs of the light receiving elements 55a to 55d are defined as follows using I _{1 to} I ₄ shown in FIG.

FIG. 16 shows a detection result by simulation of X displacement when the above-described 4-division PD 55 is used, and FIG. 17 shows a detection result by simulation of Y displacement when the 4-division PD 55 is used. 16 and 17, the X displacement is indicated by a solid line, and the Y displacement is indicated by a one-dot chain line. As shown in FIGS. 16 and 17, it can be seen that the displacement can be detected in a shape close to a sine wave.

  Furthermore, as shown in FIG. 18, by using two probes, the rotation in the θz direction can also be obtained from the relative positional relationship between the X and Y displacements.

Here, a position / posture detection method using a multi-element PD will be described.
Unlike the detection method using the above-described quadrant PD 55, it is possible to detect more degrees of freedom by detecting the behavior of each spot peak using a multi-element PD. On the light receiving surface 36a (see FIG. 8) of the light receiving unit 36, a large number of peaks are arranged in a constant cycle in the XY direction. Among the many peaks, photodiodes 51 to 54 and 56 to 59 as shown in FIG. 19 are arranged for the central nine peaks. In this light receiving portion 36, one photodiode 52, 54, 56, 58 is disposed on four sides of the light receiving surface 36a, and squares are cut into two corners 51, 53, 57 at four corners of the light receiving surface 36a. , 59 are arranged. A method for detecting the three degrees of freedom of the position / orientation using the light receiving unit 36 composed of the multi-element type PD will be described in the order of the XY position detection method and the θz detection method.

First, a method for detecting the XY position will be described.
20A to 20E show a method for detecting the displacement in the X direction of the first embodiment as an example. When displacement occurs in the X direction, as shown in FIGS. 20A to 20E, the height distribution of the spot peaks on the photodiodes 51 to 54 and 56 to 59 changes only in the X direction. Therefore, by using the sensor output in the X direction of the light receiving unit 36 as S _X , and using the detected intensity values I _X1 and I _X2 of the photodiodes 54 and 56 arranged at the intermediate positions of the two sides in the X direction of the light receiving surface 36a, Obtained from calculation of equation (14). Similarly, in the Y direction, the sensor output of the light receiving unit 36 is S _Y , and the intensity detection values I _Y1 and I _Y2 of the photodiodes 52 and 58 arranged at the intermediate positions of the two sides in the Y direction of the light receiving surface 36a are used. Obtained from calculation in (15).

Next, a detection method in the θz direction around the Z axis will be described.
When θz rotation occurs, the whole spot of light 42 _{1-42 9} rotates by the same θz as an axis the peak of spot center. Therefore, θz can be detected by detecting a change in the intensity of the spot using eight light receiving elements of two divided PDs 51, 53, 57, 59 arranged at the four corners of the light receiving surface 36a. FIGS. 21A to 21C show the detection principle of the XY position detection method of the first embodiment. The outputs of the eight light receiving elements 51a, 51b, 53a, 53b, 57a, 57b, 59a, 59b of the two-divided PDs 51, 53, 57, 59 are I _θz1 , I _θz2 , I _θz3 , I _θz4 , I _θz5 , I _θz6. , I _θz7 , I _θz8 , the output S _θz of the light receiving unit 36 in the θz direction can be obtained from the following equation (16).

FIG. 22 shows the detection result of the X direction displacement of the first embodiment, FIG. 23 shows the detection result of the Y direction displacement of the first embodiment, and FIG. 24 shows the detection result of the θz direction of the first embodiment. As shown in FIG. 22, since the S _X with respect to X-direction displacement, S _{[theta] Y,} S _.theta.Z changes by a curve similar to a sine wave, it can be seen that detect X-direction displacement. Thus, the X-direction displacement can be detected by the photodiodes 54 and 56.

Further, as shown in FIG. 23, it can be seen that the displacement in the Y direction can be detected because S _Y , S _θX , and S _θZ are displaced in a curve close to a sine wave with respect to the displacement in the Y direction. In this way, the Y-direction displacement can be detected by the photodiodes 52 and 58.

Further, as shown in FIG. 24, since the S _.theta.Z is displaced by a curve similar to a sine wave with respect to the rotation around the Z-axis, it can be seen that detect θz direction. Thus, the displacement in the θz direction can be detected from the output S _θz obtained from the outputs of the two-divided PDs 51, 53, 57, and 59. Therefore, since the X, Y direction and θz direction can be detected by the sensor output of the light receiving unit 36, the X, Y of the first stage 14 is used by using the transmission type detecting device 22 for attaching the transparent body angle grating 30 in the vertical state. It becomes possible to detect the tilt angle in the Y direction displacement, the pitching direction, and the rolling direction. Therefore, in the control device 28 (see FIG. 3) to which the detection signal from the transmission type detection device 22 is input, the X and Y directions and the θx and θz directions obtained from the light receiving unit 36 in the process of moving the first stage 14. Based on this detection signal, the linear motors 18 and 20 can be driven and controlled so that the first stage 14 suppresses the pitching operation and the rolling operation.

Note that S _θX and S _θY shown in FIGS. 22 to 24 have small outputs as detection signals, so that the output is increased by adopting a configuration in which the transparent angle grating 30 is fixed to the back surface of the substrate 32. It can be used as a detection signal. As shown in FIG. 25, in the transmission type detection device 22, a pair of transparent body angle gratings 30 are fixed back to back on the front surface and the back surface of the substrate 32, that is, a first reference provided on the front side of the substrate 32. The position of each of the X direction and the Y direction excluding the Z direction, and each of the positions by each of the grating 30 and the second reference grating 30 provided on the back side of the substrate 32 so as to be 180 degrees with the first reference grating 30. It becomes possible to obtain detection signals of the angles θx, θy, and θz around the axis.

A configuration of a reflection type detection device 70 used as a reflection type surface encoder will be described with reference to FIG.
As shown in FIG. 26, the reflection-type detection device 70 holds the transparent body angle grating (reference grating) 30 formed in the moving direction of the first stage 14 and the transparent body angle grating 30 in a vertical state. A substrate 74 on which a reflection surface (mirror) 74a is formed, and an optical sensor unit 76 that emits a plurality of parallel lights toward the transparent body angle grating 30 and receives the reflection light from the reflection surface 74a. The optical sensor unit 76 includes a light emitting unit (not shown) that emits a plurality of parallel lights, and a light receiving unit (not shown) that receives a plurality of reflected lights that are transmitted through the transparent angle grating 30 and reflected by the reflecting surface 74a. ).

  In the reflection type detection device 70, the optical sensor unit 76 is provided on the side facing the detection surface 30a of the transparent body angle grating 30, so that the transparent body angle grating 30 is more linear than the first embodiment described above. Accordingly, it is possible to detect the angles θx, θy, and θz about the X direction, the Y direction, and each axis at a position close to the linear motor 18 correspondingly.

Here, the principle of the state detection of the reflection type detection device 70 will be described.
FIG. 27 shows a model of the transparent body angle grating 30 attached to the reflecting surface 74a. The shape of the detection surface 30a of the transparent angle grating 30 is a two-dimensionally superimposed sine wave as shown in the equation (17) as in the first embodiment.

Here, the pitches P _x and P _y of the surface shape of the transparent angle grating 30 are on the order of several hundred μm or less, and the amplitudes A _x and A _y are on the order of several hundred nm or less. Play a role like this. Therefore, here, in the same manner as in the first embodiment described above, in setting up the model of the reflection type detection device 70, light was treated as a wave, and analysis was performed by calculating the amplitude and phase. That is, what is used here is not a geometric optics model but a wave optics model.

  In the following description, it is assumed that light enters the position (x, y) from the vertical direction of the transparent body angle grating 30 as shown in FIG. At this time, when traveling from the surface Σ to the reflecting surface 74a of the substrate 74, the light travels by the distance 2A-h (x, y), and then enters the transparent body angle grating 30, and only by the distance h (x, y). move on. Then, the light reflected by the reflecting surface 74a follows the same optical path again and proceeds to the surface Σ.

  FIG. 28 shows a virtual model in which light is transmitted as it is where it is reflected by the reflecting surface 74a. At this time, when the refractive index of the transparent body angle grating 30 is n and the refractive index outside the transparent body angle grating 30 is 1, this light is incident from the surface Σ and travels again to the surface Σ (Σ ′ in FIG. 28). The optical path length L is expressed as shown in Equation (18).

When the light travels from the plane Σ to the plane Σ again, there is an optical path length of L, so that the phase is delayed by kL multiplied by the wave number k (= 2π / λ, λ: wavelength of light). Therefore, the phase function Gr (x, y) of the transparent body angle grating 30 can be expressed as the following equation (19).

When displacement in the X direction and Y direction and rotation about the X, Y, and Z axes occur in the transparent body angle lattice 30, Expression (20) can be expressed as the following Expression (21).

The above is the model of the transparent body angle lattice 30 attached to the reflecting surface 74a.

  FIG. 29 shows an optical system of the reflection type detection device 70 of the second embodiment. In FIG. 29, the same parts as those in the first embodiment are denoted by the same reference numerals.

  Since the optical sensor unit 76 includes the light emitting unit 34 and the light receiving unit 36, it is possible to reduce the size of the entire apparatus as compared with the case where the light emitting unit 34 and the light receiving unit 36 are provided separately. The parallel light 40 emitted from the laser light source (LD) 34a of the light emitting unit 34 is incident on a spectroscopic plate 38 having a grid pattern in which minute openings are arranged two-dimensionally at a constant period.

In the spectroscopic plate 38, the lights diffracted by the micro openings 38 </ b> A to 38 </ b> I of the grid pattern interfere with each other and pass through the deflecting beam splitter (PBS) 78 and the quarter wavelength plate 80. Then, on the transparent body angle lattice 30, nine parallel lights 42 _{1 to} 42 ₉ having peaks at the same interval as the opening interval of the grid pattern are generated.

  Further, after passing through the transparent body angle grating 30 and reflected by the reflecting surface 74 a and again through the transparent body angle grating 30, it is reflected by the deflection beam splitter 78 in the direction of 90 degrees, and is received by the light receiving unit 36 by the objective lens 44. It is condensed on the surface 36a.

  Similar to the method described in the first embodiment, the intensity distribution I (x, y) on the light receiving surface 36a of the light receiving unit 36 is obtained by combining this model and is as follows.

FIG. 30 shows the result of calculating the intensity distribution I (x, y) according to the equation (22). The simulation conditions at this time are as shown in Table 2.

As can be seen from the results shown in FIG. 30, it can be seen that a large number of peaks are arranged at a constant period. This is because when the light passes through the grid pattern and the transparent body angle grating 30, the light is diffracted and interferes and is generated on the objective lens 44.

Here, the intensity change of each spot irradiated with the parallel lights 42 _{1 to} 42 ₉ when X displacement occurs will be described.
Results of examination by simulation of how the intensity distribution shown in FIG. 30 changes when the optical sensor unit 76 provided on the movable side is displaced in the X direction with respect to the transparent body angle grating 30 attached to the fixed side. Are shown in FIGS. 31 (A) to (E). As can be seen from FIGS. 31A to 31E, the peak height distribution in the X direction changes. Further, it can be seen from FIG. 31 that the distribution in the Y direction has not changed.

Next, each spot change irradiated with the parallel lights 42 _{1 to} 42 ₉ when the Y displacement occurs will be described.
When the optical sensor unit 76 is displaced in the Y direction with respect to the transparent body angle grating 30, how the intensity distribution in FIG. 30 changes is examined by simulation, as shown in FIGS. 32 (A) to (E). Results were obtained. As shown in FIGS. 32A to 32E, it can be seen that the height distribution of the peak in the Y direction changes as in the case of displacement in the X direction. It can also be seen that the distribution in the X direction has not changed.

Next, the intensity change of each spot when rotation in the θx direction around the X axis occurs will be described.
Examination of how the intensity distribution in FIG. 30 changes when the rotation in the θx direction occurs with respect to the transparent body angle grating 30 yields the results shown in FIGS. 33 (A) to (E). It was. As shown in FIGS. 33 (A) to (E), since the change in the spot is small and difficult to understand, the peaks at the centers of the spots in FIGS. 33 (A) to (E) are shown in FIGS. The enlarged view of is shown. 34A to 34E show that the spot peak moves in the Y direction.

Next, the intensity change of each spot when the θ _Y rotation occurs will be described.
It was examined by simulation how the intensity distribution shown in FIG. 30 changes when θ _Y rotation occurs in the transparent angle grating 30. FIGS. 35A to 35E show the intensity change of each spot when θ _Y rotation occurs. Here, in FIGS. 35A to 35E, since the spot intensity change is hardly seen, the peaks at the centers of the spots in FIGS. 35A to 35E are shown in FIGS. The enlarged view of is shown. 36A to 36E show that the peak moves in the X direction.

Next, the intensity change of each spot when rotation in the θz direction around the Z axis occurs will be described.
When the intensity distribution in FIG. 30 changes when the rotation in the θz direction with respect to the transparent body angle lattice 30 is examined by simulation, the results shown in FIGS. 37A to 37E are obtained. It was. As shown in FIGS. 37 (A) to (E), since almost no change in the spot is observed, FIGS. 38 (A) to (E) show some of the spots in FIGS. 37 (A) to (E). An enlarged view is shown. It can be seen that when the rotation in the θz direction occurs, the entire spot rotates by the same angle θz with the peak at the center of the spot (here, the strongest peak) as an axis.

Here, a position detection method using the quadrant PD 55 will be described.
It was found that, with respect to the displacement of the transparent body angle grating 30 in the X direction and the Y direction, the peak intensity changes only in the X direction and the Y direction, respectively. By utilizing this, it is possible to detect these displacements using the same 4-division PD 55 shown in FIG. The detection principle of the quadrant PD 55 is the same as that described above, and is omitted here.

  FIG. 39 shows the detection result of the X displacement simulation of the second embodiment, and FIG. 40 shows the detection result of the Y displacement simulation of the second embodiment. As shown in FIGS. 39 and 40, it can be seen that the X and Y displacements can be detected with a shape close to a sine wave as in the case of the first embodiment.

  Furthermore, on the same principle as the transmission scale shown in FIG. 18 described above, the rotation of θz can be obtained from the relative positional relationship between the two probes shown in FIGS. 39 and 40 using the two probes.

Further, [theta] x by detecting the amount of movement of the spot relative to the transparent body angle grating 30, it is possible to detect the theta _Y.

Next, a position / posture detection method using a multi-element PD will be described.
The 4 Unlike the detection method using a split PD55, can be detected more flexibility by detecting a peak every single behavior of the spot of the light 42 _{1-42 9} by the photodiode 51 to 59 become. On the light receiving surface 36a of the light receiving unit 36, detection is made so that a large number of peaks are arranged in a constant cycle in the XY direction. Among the many peaks, the photodiodes 51 to 59 are arranged on the light receiving surface 36a as shown in FIG. This is a four-part PD 55 disposed in the center in addition to the photodiodes 51 to 54 and 56 to 59 shown in FIG.

Next, a method for detecting the five degrees of freedom of the position / orientation using the light receiving unit 36 will be described. However, the detection method of the XY position and the detection method of θz are the same as those in the above-described first embodiment. here, the description is omitted, [theta] x, describes method for detecting the rotation of the theta _Y direction.

Emitting portion 34 is θx relative to the transparent body angle grating 30, theta when rotated in the _Y-direction, each spot of the transparent body angle detection surface each light ₄₂ 1 is irradiated to 30a of the grid 30 to 42 ₉ are each X, Y Move in the direction.

Therefore, by detecting the amount of movement of the spot in the X and Y directions by using the four-divided PD55 located in the same way as normal autocollimation method in the center of the light receiving surface 36a, [theta] x, the rotation of the theta _Y direction detected it can. 41A to 41C show the principle of detection of rotation in the _θY direction of the second embodiment as an example. 41 (A) to 41 (C), if the outputs of the _{quadrant PD 55} are I _{θxy 1} , I _{θxy 2} , I _{θxy 3} , and I _{θxy 4} , the sensor θ _Y output S _θY and θx output S _θX are expressed by the following equations (23), It is calculated from (24).

FIG. 42 shows the detection result of the displacement in the X direction according to the second embodiment. FIG. 43 shows the detection result of the Y direction displacement of the second embodiment. 42 and 43, it can be seen that the X, Y displacement can be detected with a shape close to a sine wave. FIG. 44 shows the detection result of θx of the second embodiment, and FIG. 45 shows the detection result of θ _Y of the second embodiment. FIG. 46 shows the detection result in the θz direction of the second embodiment.

Thus, in the reflective type sensing device 70 consists of a change in detected intensity distribution by the photodiode 51 to 59 X, Y-direction and [theta] x, theta _Y, can also be detected rotational movement of θz direction.

The configuration of the reflection type detection device 90 using the reflection surface angle grating will be described with reference to FIG.
As shown in FIG. 47, the reflection-type detection device 90 holds the reflection surface angle grating (reference grating) 92 extending in the moving direction of the first stage 14 and the reflection surface angle grating 92 in a vertical state. A substrate 94 and an optical sensor unit 76 that emits a plurality of parallel lights toward the reflecting surface angle grating 92 and receives the reflected lights are provided. The reflection surface angle grating 92 has a reflection film that reflects light on the surface of the detection surface 92a. The optical sensor unit 76 includes a light emitting unit (not shown) that emits a plurality of parallel lights, and a light receiving unit (not shown) that receives a plurality of reflected lights reflected by the detection surface 92a of the reflecting surface angle grating 92. Have.

  In the reflection type detection device 90, the optical sensor unit 76 is provided on the side facing the detection surface 92a of the reflection surface angle grating 92. Therefore, the reflection surface angle grating 92 is more linear than the one in the first embodiment. Accordingly, it is possible to detect the angles θx, θy, and θz about the X direction, the Y direction, and each axis at a position close to the linear motor 18 correspondingly.

  Here, the principle of the state detection of the reflection type detection device 90 will be described.

  FIG. 48 shows a model of the reflecting surface angle grating 92. The shape of the reflecting surface angle grating 92 is a two-dimensionally superimposed sine wave as shown in the equation (25), as in the first and second embodiments.

Here, the pitches P _x and P _y of the surface shape of the reflecting surface angle grating 92 are on the order of several hundred μm or less, and the amplitudes A _x and A _y are on the order of several hundred nm or less. Play a role like this. Therefore, in order to build an encoder model, light was treated as a wave and analyzed by calculating the amplitude and phase. That is, what is used here is not a geometric optics model but a wave optics model.

  As shown in the figure, it is assumed that light is incident on the position (x, y) substantially vertically from above the reflecting surface angle grating 92. At this time, the light travels from the surface Σ by a distance 2A-h (x, y), and is then reflected by the reflective film formed on the detection surface 82a of the reflective surface angular grating 92. Further, the optical path length L when the light enters from the surface Σ and travels again to the surface Σ (Σ ′ in FIG. 2) is expressed by Expression (26).

When traveling from the plane Σ to the plane Σ again, there is an optical path length of L, so that the phase is delayed by kL multiplied by the wave number k (= 2π / λ, λ: wavelength of light). Therefore, the phase function Gr (x, y) of the reflecting surface angle grating 92 can be expressed as the following equation (27).

When displacement in the X direction and Y direction and rotation about the X, Y, and Z axes occur in the reflecting surface angle grating 92, Expression (28) can be expressed as Expression (29) below.

The above is the model of the reflecting surface angle grating 92.

Next, a reflection type detection device 90 using the reflection surface angle grating 92 will be described.
FIG. 49 shows the optical system of the reflective surface encoder of the third embodiment. In FIG. 49, the same parts as those in the second embodiment are denoted by the same reference numerals.

  As shown in FIG. 49, since the optical sensor unit 76 has a configuration having the light emitting unit 34 and the light receiving unit 36, the entire apparatus is reduced in size compared to the case where the light emitting unit 34 and the light receiving unit 36 are provided separately. It becomes possible to do. The parallel light 40 emitted from the laser light source (LD) 34a of the light emitting unit 34 is incident on a spectroscopic plate 38 having a grid pattern in which minute openings are arranged two-dimensionally at a constant period.

In the spectroscopic plate 38, the lights diffracted by the micro openings 38 </ b> A to 38 </ b> I of the grid pattern interfere with each other and pass through the deflecting beam splitter (PBS) 78 and the quarter wavelength plate 80. Then, on the transparent body angle lattice 30, nine parallel lights 42 _{1 to} 42 ₉ having peaks at the same interval as the opening interval of the grid pattern are generated.

  Further, the light is reflected by the reflection film on the detection surface 92 a of the reflection surface angle grating 92, reflected by the deflecting beam splitter 78 in the direction of 90 degrees, and collected by the objective lens 44 on the light receiving surface 36 a of the light receiving unit 36.

  Similar to the method described in the first embodiment, the intensity distribution I (x, y) on the light receiving surface 36a of the light receiving unit 36 is obtained by combining this model and is as follows.

Next, the simulation result of Example 3 will be described.
FIG. 50 shows the result of calculating the intensity distribution I (x, y) according to the above equation (30). The simulation conditions at this time are as shown in Table 3.

As can be seen from the simulation results shown in FIG. 50, it can be seen that a large number of peaks are arranged at a constant period. This is because when light is reflected by the grid pattern of the spectroscopic plate 38 and the reflection surface angle grating 92, the light is diffracted by them and interferes and is generated on the objective lens 44.

Next, the intensity change of each spot irradiated with the parallel lights 42 _{1 to} 42 ₉ when X displacement occurs will be described.
It was examined by simulation how the intensity distribution shown in FIG. 50 changes when the optical sensor unit 76 provided on the movable side with respect to the fixed-side reflecting surface angle grating 92 is displaced in the X direction. 51A to 51E show changes in the intensity of each spot when X displacement occurs. As can be seen from FIGS. 51A to 51E, the peak height distribution in the X direction changes. In addition, it can be seen from FIGS. 51A to 51E that the distribution in the Y direction does not change.

Next, the intensity change of each spot when Y displacement occurs will be described.
It was examined by simulation how the intensity distribution shown in FIG. 50 changes when the optical sensor unit 76 is displaced in the Y direction with respect to the reflecting surface angle grating 92. 52A to 52E show the intensity change of each spot when the Y displacement occurs. 52A to 52E, it can be seen that the peak height distribution in the Y direction changes as in the case of displacement in the X direction. 52A to 52E show that the X-direction distribution is not changed.

Next, the intensity change of each spot when the θx rotation occurs will be described.
When the optical sensor unit 76 is rotated in the θx direction with respect to the reflection surface angle grating 92, the simulation examined how the intensity distribution shown in FIG. 50 changes. 53A to 53E show changes in intensity of each spot when the θx rotation occurs. In FIGS. 53 (A) to 53 (E), almost no change in the spot is observed, and therefore, enlarged views of the peaks at the centers of the spots in FIGS. 53 (A) to (E) are shown in FIGS. Show. 54A to 54E show that the peak moves in the Y direction.

Next, the intensity change of each spot when the _θY rotation occurs will be described.
When the optical sensor unit 76 is rotated in the _θY direction with respect to the reflection surface angle grating 92, the simulation examined how the intensity distribution shown in FIG. 50 changes. FIGS. 55A to 55E show the intensity change of each spot when the _θY rotation occurs. In FIGS. 55 (A) to (E), since almost no change is observed in each spot, the peaks at the centers of the spots in FIGS. 55 (A) to (E) are enlarged in FIGS. 56 (A) to (E). The figure is shown. 56A to 56E show that the peak moves in the X direction.

Next, the intensity change of each spot when the θz rotation occurs will be described.
When the optical sensor unit 76 is rotated in the θz direction with respect to the reflecting surface angle grating 92, how the intensity distribution in FIG. 57A to 57E show intensity changes when θz rotation occurs. Here, in FIGS. 57 (A) to (E), almost no change in the intensity of the spot is seen, and therefore some of the spots in FIGS. 57 (A) to (E) are shown in FIGS. An enlarged view is shown. 57A to 57E, it can be seen that when the rotation in the θz direction occurs, the entire spot rotates by the same θz around the peak at the center of the spot.

Next, a position detection method using the quadrant PD 55 will be described.
It was found that the peak intensity of the spot intensity changes only in the X direction and the Y direction with respect to the displacement in the X direction and the Y direction of the reflecting surface angle grating 92, respectively. By utilizing this, it is possible to detect these displacements using the same 4-division PD 55 shown in FIG. Since the detection principle by the four-divided PD 55 is the same as that of the first embodiment, the description thereof is omitted here.

Subsequently, a simulation result of Example 3 will be described below.
FIG. 59 shows the detection result of the X displacement of the third embodiment, and FIG. 60 shows the detection result of the Y displacement of the third embodiment. It can be seen from FIGS. 59 and 60 that the X and Y displacement can be detected with a shape close to a sine wave.

Further, using the two probes shown in FIGS. 59 and 60 based on the same principle as the transmission scale shown in FIG. 18 described above, θz can be calculated from the relative positional relationship between the reflecting surface angle grating 82 and the optical sensor unit 76. Rotation can also be determined. Can also be detected [theta] x, the theta _Y by detecting the amount of movement of the spot.

Next, a position / posture detection method using the light receiving unit 36 having a multi-element PD will be described.
More degrees of freedom can be detected by detecting the behavior of each spot peak using the light receiving unit 36 shown in FIG. 8 in the same manner as described in the second embodiment. Since the detection principle is the same as that of the second embodiment described above, a description thereof will be omitted.

Next, a simulation result of the light receiving unit 36 having a multi-element type PD will be described.
FIG. 61 shows the X displacement detection result of Example 3, and FIG. 62 shows the Y displacement detection result of Example 3. As shown in FIGS. 61 and 62, it can be seen that the X and Y displacement can be detected with a shape close to a sine wave. FIG. 63 shows the detection result of θx of Example 3, and FIG. 64 shows the detection result of θ _Y of Example 3. FIG. 65 shows the detection result of θz in Example 3.

Thus, in the reflective type sensing device 90 consists of a change in detected intensity distribution by the photodiode 51 to 59 X, Y-direction and [theta] x, theta _Y, can also be detected rotational movement of θz direction.

  FIG. 66 is a diagram showing an optical sensor unit 100 according to a fourth embodiment used in a reflection type detection device. In FIG. 66, the same parts as those of the optical sensor unit 76 of the second embodiment shown in FIG.

  As shown in FIG. 66, the optical sensor unit 100 includes a light emitting unit 34 and a light receiving unit 36, and the parallel light 40 emitted from the laser light source (LD) 34a of the light emitting unit 34 functions as a spectroscopic unit. Is incident on the incident surface 102a of the transparent angle grating 102.

  The incident surface 102a of the transparent body angle grating 102 is configured in the same shape as the detection surface 30a of the transparent body angle grating 30 described above. In other words, the incident surface 102a has a three-dimensional concave curved surface and convex curved surface alternately formed in a two-dimensional direction on the right side of the contour of a sinusoidal shape having a predetermined radius of curvature. The concave / convex shape of the incident surface 102a is such that fine concave curved surfaces and convex curved surfaces are formed uniformly and with high accuracy in the same manner as the transparent body angle grating 30 described above.

  The light emitting unit 34 is provided so as to face the incident surface 102a of the transparent body angle grating 102 from the vertical direction. Since the parallel light 40 emitted from the light emitting unit 34 is irradiated on the entire incident surface 102a, the concave curved surface and the convex curved surface of the incident surface 102a function as a fine lens, so that the light diffused on the concave curved surface and the convex curved surface The light converged at is split into a plurality of overlapping light. At this time, the number and pitch of the dispersed light can be selectively set according to the curvature radius of the concave curved surface and the convex curved surface.

  Therefore, by using the transparent body angle grating 102 as the spectroscopic means instead of the above-described spectroscopic plate 38, it becomes possible to perform spectroscopic analysis more precisely than the spectroscopic plate 38.

The light split by the transparent angle grating 102 passes through a deflecting beam splitter (PBS) 78 and a quarter-wave plate 80. Then, on the transparent body angle grating 30, parallel lights 42 _{1 to} 42 _n having peaks at predetermined intervals are generated.

  Further, after passing through the transparent body angle grating 30 and reflected by the reflecting surface 74 a and again through the transparent body angle grating 30, it is reflected by the deflection beam splitter 78 in the direction of 90 degrees, and is received by the light receiving unit 36 by the objective lens 44. It is condensed on the surface 36a.

  Here, a simulation result when the transparent body angle grating 102 is used as the spectroscopic means will be described.

  In the detection device as a surface encoder that combines a transparent body angle grating 102 having an incident surface 102a having a shape in which a fine sine wave is developed two-dimensionally and a two-dimensional angle sensor, the transparent device has the same shape as the sine wave angle grating 30. By using the body angle grating 102, an optical system with high beam efficiency can be realized, and similarly, a multi-degree-of-freedom position detection can be performed as a relative displacement between the transparent body angle grating 30 and the transparent body angle grating 102.

  When the effectiveness of the dual sine wave grating surface encoder using the transparent angle gratings 30 and 102 was simulated under the following conditions (see Table 4), the results shown in FIGS. 67 to 71 were obtained.

67A to 67D are graphs showing experimental data of multi-spots generated by the transparent body angle grating 102. FIG. 67A is a graph showing the intensity of the multi-spot with respect to the X direction, FIG. 67B is a graph showing the intensity of the multi-spot with respect to the Y direction, and FIG. FIG. 67D is a graph showing the intensity of a part of the multi-spot with respect to the Y direction in an enlarged manner.

  As shown in FIGS. 67 (A) to 67 (D), the multi-spot generated by the transparent body angle grating 102 can obtain a plurality of spots having periodic peaks in the X direction and the Y direction, and the X direction. In addition, it can be seen that the central strength in the Y direction is maximized.

  Here, for convenience of explanation, a detection simulation result in the case where a quadrant PD is used as the light receiving element of the light receiving unit 36 will be described.

FIG. 68 is a graph showing the result of analyzing the intensity distribution of the light receiving spot received on the 4-split PD. As shown in FIG. 68, it can be seen that parallel lights 42 _{1 to} 42 _n whose intensity peaks at a predetermined interval are detected on the quadrant PD.

  69 (A) to 69 (D) are graphs showing changes in multi-spots when the transparent body angle grating 30 is relatively displaced (Y = 0) in the X direction. In the displacement state shown in FIG. 69 (B) from the stopped state in FIG. 69 (A), the left side (−side from X = 0) of the multi-spot peak distribution decreases and the right side (+ side from X = 0). It can be seen that the transparent body angle grating 30 is displaced to the right side (X side from X = 0) by the peak value protruding. In addition, in the displacement state shown in FIG. 69D from the stopped state in FIG. 69C, the right side (−side from X = 0) of the multi-spot peak distribution decreases and the left side (from X = 0 to the + side). It can be seen that the transparent angle grating 30 is displaced to the left (X side minus X = 0) due to the peak value of.

  FIGS. 70A to 70D are graphs showing changes in multi-spots when the transparent body angle grating 102 is relatively displaced (X = 0) in the Y direction. In the displacement state shown in FIG. 70B from the stop state of FIG. 70A, the front side (−side from Y = 0) of the multi-spot peak distribution is reduced and the back side (+ side from Y = 0). It can be seen that the transparent body angle grating 30 is displaced to the rear side (+ side from Y = 0) by protruding the peak value. Further, in the displacement state shown in FIG. 70D from the stopped state in FIG. 70C, the rear side (+ side from Y = 0) of the multi-spot peak distribution decreases and the front side (from Y = 0 to −). It can be seen that the transparent body angle grating 30 is displaced to the front side (Y side from Y = 0) by the peak value on the side) protruding.

  FIG. 71 shows the experimental results simulating the output change with respect to the X-direction displacement of the 4-part PD. FIG. 72 shows the experimental results simulating the output change with respect to the Y-direction displacement of the 4-part PD.

  As shown in FIG. 71, it can be seen that when the relative displacement of the X direction displacement occurs, the output in the Y direction does not change, but the output in the X direction changes in a sine wave form. In addition, as shown in FIG. 72, it can be seen that when the relative displacement of the Y direction displacement occurs, the output in the X direction does not change, but the output in the Y direction changes in a sine wave form.

  Thus, by using the transparent body angle grating 102 as the spectroscopic means, it is possible to detect the relative displacement of the X direction displacement and the relative displacement of the Y direction displacement from the output change of the light receiving unit 36. Was verified.

  Further, by using a multi-element type PD (see FIG. 8 described above) or a CCD element as the light receiving element of the light receiving unit 36, an inclination posture by rotation around each axis such as pitching, rolling, yawing, etc. in addition to the XY position. Can also be measured.

  In the above embodiment, the detection device for detecting the position of the stage has been described as an example. However, the present invention is not limited to this, and it is a matter of course that the moving position of other movable bodies and the state (tilt) associated with the movement can be detected. is there.

  In addition, as a detection device, for example, it can be applied to a rotary encoder as well as a linear encoder, and as a device other than a stage device, it can also be applied to a hard disk device or a digital video disk device. it can.

  The present invention can also be applied to an input device of a personal computer such as a mouse or an input device of a computer game device.

  In addition, it can be applied to logistics-related object information (for example, package location information) and product two-dimensional barcode detection devices, so it can be applied to high-density optical tags equivalent to IC tags. is there.

It is the schematic of the conventional detection apparatus which has a reference | standard grating | lattice and a two-dimensional angle sensor. It is the figure which showed the structural example of the two-dimensional angle sensor. It is a conceptual diagram which shows the main components of the stage apparatus to which Example 1 of the detection apparatus according to the present invention is applied. 2 is a perspective view showing a configuration of a transmission type detection device 22. FIG. 4 is an enlarged perspective view showing a state in which a plurality of lights are irradiated on a detection surface of a transparent body angle grating 30. FIG. It is the block diagram which looked at the structure of the transmissive | pervious detection apparatus 22 from the X direction. It is a figure which expands and shows an example of the grid pattern of the spectroscopic plate. It is a figure which expands and shows the light-receiving surface 36a in which the photodiodes 51-59 are arrange | positioned. It is a figure which shows the model in which light injects into the transparent body angle grating | lattice 30 in position (x, y). 6 is a graph showing a simulation result of intensity distribution I (x, y) of Example 1. 6 is a graph showing a simulation result of a change in intensity distribution when a light emitting unit is rotated in the X direction with respect to a transparent body angle grating. 6 is a graph showing a simulation result of a change in intensity distribution when a light emitting unit is rotated in the Y direction with respect to a transparent body angle grating. 6 is a graph showing a simulation result of a change in intensity distribution when the light emitting unit is rotated in the _θZ direction with respect to the transparent body angle grating. It is a graph which expands and shows a part of spot of Drawing 13 (A)-(E). It is a figure which expands and shows 4 division | segmentation PD55. It is a graph which shows the detection result by the simulation of X displacement at the time of using 4 division | segmentation PD55. It is a graph which shows the detection result by the simulation of Y displacement at the time of using 4 division | segmentation PD55. It is a figure for demonstrating the method of also calculating | requiring the rotation of (theta) z direction from the relative positional relationship of a X, Y displacement. FIG. 6 is a diagram illustrating an arrangement of photodiodes 51 to 54 and 56 to 59 of the light receiving unit 36. It is a figure which shows the method of detecting the displacement of the X direction of Example 1. FIG. It is a figure which shows the detection principle of the detection method of the XY position of Example 1. FIG. 6 is a graph showing the detection result of the displacement in the X direction in Example 1; 3 is a graph showing a detection result of displacement in the Y direction in Example 1. 6 is a graph illustrating a detection result in the θz direction according to the first embodiment. 7 is a diagram of an optical system showing a modification of Example 1. FIG. It is a perspective view which shows the structure of the reflection type detection apparatus 70 of Example 2. FIG. It is a figure which shows the model of the transparent body angle lattice 30 affixed on the reflective surface 74a of Example 2. FIG. It is a figure which shows the model hypothesized so that the light of Example 2 may be transmitted as it is where it is reflected by the reflecting surface 74a. It is a figure which shows the optical system of the reflection type detection apparatus 70 of Example 2. FIG. 6 is a graph showing a simulation result of intensity distribution I (x, y) of Example 2. It is a graph which shows the simulation result of the change of intensity distribution when displaced to the X direction with respect to the transparent body angle lattice. It is a graph which shows the simulation result of the change of intensity distribution when displaced to the Y direction to transparent body angle lattice 30. 6 is a graph showing a simulation result of a change in intensity distribution when rotation in the θx direction occurs with respect to the transparent body angle grating 30. It is a graph which expands and shows the peak of the center of the spot of FIG. 33 (A)-(E). It is a graph which shows the intensity | strength change of each spot when (theta) _Y rotation of Example 2 arises. It is a graph which expands and shows the peak of the center of the spot of FIG. 35 (A)-(E). It is a graph which shows an intensity | strength change when rotation arises in the (theta) z direction of Example 2. FIG. It is a graph which expands and shows a part of spot of FIG. 37 (A)-(E). 6 is a graph showing a detection result of a simulation of X displacement in Example 2. 6 is a graph showing a detection result of simulation of Y displacement in Example 2. It is a figure which shows the detection principle of the rotation of (theta) _Y direction of Example 2. FIG. 6 is a graph showing the detection result of the displacement in the X direction in Example 2. 10 is a graph showing a detection result of displacement in the Y direction in Example 2. 6 is a graph illustrating a detection result of θx in Example 2. 6 is a graph showing the detection result of θ _Y in Example 2. 6 is a graph showing a detection result in the θz direction of Example 2. It is a perspective view which shows the structure of the reflection type detection apparatus 90 using the reflective surface angle grating | lattice of Example 3. FIG. 6 is a diagram illustrating a model of a reflecting surface angle grating 92 according to Embodiment 3. FIG. 6 is a diagram illustrating an optical system of a reflective surface encoder according to Embodiment 3. FIG. 10 is a graph showing a simulation result of an intensity distribution I (x, y) of Example 3. It is a graph which shows the intensity | strength change of each spot when X displacement of Example 3 arises. It is a graph which shows the intensity | strength change of each spot when Y displacement of Example 3 arises. It is a graph which shows the intensity | strength change of each spot when the θx rotation of Example 3 arises. It is a graph which expands and shows the peak of the center of the spot of FIG. 53 (A)-(E). It is a graph which shows the intensity | strength change of each spot when (theta) _Y rotation of Example 3 arises. It is a graph which shows the enlarged view of the peak of the center of each spot of FIG. 55 (A)-(E). It is a graph which shows an intensity | strength change when the θz rotation of Example 3 arises. It is a graph which expands and shows a part of spot of FIG. 57 (A)-(E). 10 is a graph showing the detection result of X displacement in Example 3. 10 is a graph showing a detection result of Y displacement in Example 3. 10 is a graph showing the detection result of X displacement in Example 3. 10 is a graph showing a detection result of Y displacement in Example 3. 10 is a graph showing the detection result of θx in Example 3. 10 is a graph illustrating a detection result of θ _Y in Example 3. 10 is a graph showing the detection result of θz in Example 3. It is a figure which shows the optical sensor unit 100 of Example 4 used for a reflection type detection apparatus. 10 is a graph showing experimental data of multi-spots generated by the transparent body angle grating 102 of Example 4. 10 is a graph showing the result of analyzing the intensity distribution of a light receiving spot received on a 4-split PD of Example 4. It is a graph which shows the change of the multi spot when the transparent body angle grating | lattice 30 of Example 4 carries out relative displacement (Y = 0) to a X direction. It is a graph which shows the change of the multi spot when the transparent body angle grating | lattice 30 of Example 4 carries out relative displacement (X = 0) in the Y direction. It is the experimental result which simulated the output change with respect to the X direction displacement of 4-part dividing PD of Example 4. FIG. It is the experimental result which simulated the output change with respect to the Y direction displacement of 4 division PD of Example 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Stage apparatus 12 Base 14 1st stage 16 2nd stage 18, 20, 24 Linear motor 22 Transmission type detection apparatus 28 Control apparatus 30,102 Transparent body angle grating 32 Transparent substrate 34 Light emission part 34a Laser light source (LD)
36 Photodetector 38 Spectral Plates 51-59 Photodiode 70 Reflective Detection Device 74 Substrate 76, 100 Optical Sensor Unit 78 Deflection Beam Splitter (PBS)
90 Reflective detector 92 Reflector angle grating

Claims (12)

A reference grating having a detection surface in which concave and convex curved surfaces having a predetermined radius of curvature are alternately formed in a two-dimensional direction on the surface;
A light emitting unit that is movable with respect to the reference grating and emits a plurality of parallel lights from a vertical direction of the reference grating toward the detection surface;
A light receiving unit that is provided so as to move integrally with the light emitting unit, and that has a plurality of light receiving elements that receive the plurality of parallel lights transmitted through the reference grating;
A detection device comprising: A reference grating having a detection surface in which concave and convex curved surfaces having a predetermined radius of curvature are alternately formed in a two-dimensional direction on the surface;
A reflective surface formed on the back surface of the reference grating;
A light emitting unit that is movable with respect to the reference grating and emits a plurality of parallel lights from a vertical direction of the reference grating toward the detection surface;
A light receiving unit that is provided so as to move integrally with the light emitting unit, and that has a plurality of light receiving elements that receive a plurality of parallel lights reflected from the reflecting surface;
A detection device comprising: A reference grating having a detection surface in which concave and convex curved surfaces having a predetermined radius of curvature are alternately formed in a two-dimensional direction on the surface;
A reflective surface formed on the detection surface;
A light emitting unit that is movable with respect to the reference grating and emits a plurality of parallel lights from a vertical direction of the reference grating toward the detection surface;
A light receiving unit that is provided so as to move integrally with the light emitting unit, and that has a plurality of light receiving elements that receive a plurality of parallel lights reflected from the reflecting surface;
A detection device comprising: The light emitting unit
A light source;
A spectroscopic means for splitting light from the light source into a plurality of parallel lights;
The detection device according to claim 1, comprising:   The detection device according to claim 4, wherein the spectroscopic unit has an incident surface in which concave curved surfaces and convex curved surfaces having a predetermined radius of curvature are alternately formed in a two-dimensional direction.   6. The light receiving unit according to claim 1, wherein the light receiving unit has a larger number of light receiving elements than the plurality of parallel lights, and at least one light receiving element is arranged for one light. A detecting device according to any one of the above.   A calculation means for inputting a detection signal corresponding to the light intensity of the plurality of parallel lights received by the light receiving element and calculating a relative movement amount of the light emitting unit with respect to the reference grating from a change in each light intensity distribution. The detection apparatus according to claim 1, wherein the detection apparatus is provided.   The calculation means calculates a relative inclination angle of the light emitting unit and the light receiving unit with respect to the detection surface based on a change in light intensity distribution of the plurality of parallel lights received by the plurality of light receiving elements. The detection device according to claim 7. The reference grid is
A transparent substrate;
A first reference grating provided on the front side of the transparent substrate;
A second reference grating provided on the back side of the transparent substrate so as to be oriented at 180 degrees with the first reference grating;
The detection apparatus according to claim 1, further comprising: Base and
A stage movably provided with respect to the base;
Driving means for applying a driving force to the stage;
The detection apparatus according to any one of claims 1 to 9, which detects movement of the stage;
Control means for controlling the drive means so that the stage moves at a predetermined speed according to the detection result of the detection device;
A stage apparatus comprising: The drive means is a pair of linear motors,
The stage device according to claim 10, wherein the control unit drives the pair of linear motors in translation.   The stage device according to claim 10, wherein the detection device according to any one of claims 1 to 9 is provided in the vicinity of the linear motor.