JPH04207012A - Position detector - Google Patents

Abstract

PURPOSE:To accurately detect the relative position between the first and second objects with high accuracy by providing a linear grating on the surface of the first object and detecting diffracted light of prescribed order produced through the linear grating with a reference member provided on the second object side. CONSTITUTION:A linear grating perpendicularly deflects an incident luminous flux from a pickup box body 16 toward the second object 2 in the vicinity of alignment marks 5 and 6 on the surface of the first object 1 and a reference member 101 is provided with a photoelectric conversion means 102 and physical optic elements 3a and 4a which detect the incident position of the luminous flux on the surface of a wafer stage 17. The relative positional relation between a light projecting means and the first object 1 is detected by means of the grating 100 and member 101. The first and second detecting sections can receive luminous fluxes 7 and 8 with one sensor 22 and can find the positional deviation DELTAsigmabetween the objects 1 and 2. When the pickup box body 16 and member 101 are moved by the deviation DELTAsigma, the positional deviation in phase approaches a real value 0.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a position detection device, and is used, for example, in a proximity-type exposure device for manufacturing semiconductor devices, to detect a position detection device such as a mask or reticle (hereinafter referred to as “mask”). A position detection device suitable for performing relative positioning (alignment) between a mask and a wafer when exposing and transferring a fine electronic circuit pattern formed on one object surface onto a second object surface such as a wafer. It is related to.

(Prior Art) Conventionally, in exposure apparatuses for semiconductor manufacturing, relative alignment between a mask and a wafer has been an important element for improving performance. Particularly in alignment in recent exposure apparatuses, alignment accuracy of, for example, submicron or less is required due to the high integration of semiconductor devices.

In many alignment devices, so-called alignment throat turns for alignment are provided on the mask and the eight faces of the sea urchin, and position information obtained from these is used to align both. As an alignment method at this time, for example, the amount of deviation between both alignment patterns is detected by performing image processing, or alignment method as proposed in U.S. Pat. Using a zone plate as a pattern, irradiating the zone plate with a light beam,
At this time, this is done by detecting the position of the focal point of the light beam emitted from the zone plate on a predetermined surface.

In general, alignment methods using zone plates are
Compared to a method using a simple alignment pattern, this method has the advantage of being able to perform alignment with relatively high precision without being affected by defects in the alignment pattern.

In addition, the present applicant has previously proposed in Japanese Patent Application No. 63-226003 a position detection device that detects relative positional misalignment between a first object as a mask and a second object as a wafer. In the same issue, there are two
A physical optical element as an alignment mark having a lens action is provided, a light beam is irradiated onto the physical optical element from a light projecting means including a laser, and the diffracted light sequentially diffracted by the physical optical element is detected (detection means). It guides light. The amount of relative positional deviation between the first object and the second object is detected by determining the relative distance between the two light spots on the sensor surface.

At this time, the light projecting means is housed in a single housing along with a detection means for receiving light sequentially diffracted by two sets of physical optical elements provided on the object surface to facilitate position detection.

, (Problem to be solved by the invention) In general, if the precision of the incident position of the projected light flux (beam) from the light projecting means onto the alignment mark (physical optical element) is insufficient, the S/N of the signal obtained by the detection means will decrease. The ratio decreases and offset occurs. For this reason, high mechanical precision and high assembly precision are required.

The intensity distribution of the projected beam is generally divided into two axes of symmetry, 1. , I, and is set to be approximately a plane wave when reaching the alignment mark. For example, assume that the beam radius at which the intensity in the X direction and the X direction decreases to e-2 is wX, w. In FIG. 6, 13 is a laser, 14 is a collimator lens, and L is a light beam.

At this time, if the beam diameters WX and W are set to be large enough to cover the alignment mark, the intensity distribution of the light beam incident on the alignment mark will change even if the relative positioning accuracy between the projection beam and the alignment mark is relaxed. It becomes difficult. This makes it difficult to change the distance between the center of gravity positions of the two spots on the sensor, and improves the stability of that surface. However, the effective use of the projection beam becomes poor, resulting in problems such as a decrease in signal strength and an increase in noise components.

Conversely, if the projection beam diameter is made smaller, the aforementioned S/N ratio will improve, or the intensity distribution on the alignment mark surface will become uneven, so if the relative position between the projection beam and the alignment mark changes, the alignment mark on the mask will change. The intensity distribution of the image formed by the sensor changes, and the distance between the centers of gravity of the two light spots on the sensor, which is formed by enlarging this image, changes and the accuracy deteriorates.

Therefore, the projection beam (light projection means) and alignment mark (
By improving the positioning accuracy of the first object or the second object and setting the optimum projection beam diameter, it is possible to achieve high alignment accuracy.

However, if an attempt is made to improve the accuracy of the incident position of the projection beam onto the alignment mark surface using only a mechanical system, the problem arises that the system becomes more complex and larger, making it difficult to maintain long-term stability.

The present invention alleviates mechanical accuracy, assembly accuracy, etc. by highly accurately determining the incident position of a projection beam from a light projection means with respect to a physical optical element, which is an alignment mark provided on a first object or a second object, using a simple method. It is an object of the present invention to provide a position detection device that can perform subsequent relative position detection of a first object and a second object with high precision.

(Means for Solving the Problems) When the position detection device of the present invention performs relative position detection with a first object and a second object facing each other, it is possible to A physical optical element is formed on each of the physical optical elements, and the diffracted light generated when light is incident on the physical optical element A on one of the object surfaces from the light projection means is incident on the physical optical element B on the other object surface. When detecting the relative position of the first object and the second object by detecting the position of the light beam of the diffraction pattern generated on a predetermined surface by the physical optical element B using the detection means, A physical optical element B that has an optical action equivalent to that of the physical optical element B on the object plane or on an object plane that is substantially integrally configured with the other object.
B and a photoelectric conversion means capable of detecting the incident position of the light beam from the light projection means, and the light projection means and the physical optical element A are connected by using the photoelectric conversion means and the physical optical element BB. The feature is that the position can be set.

In particular, the photoelectric conversion means and the physical optical element BB are formed so that their relative positional relationship has a known predetermined value.

That is, in the present invention, the photoelectric conversion means and the physical optical element BB are provided on the other object surface so as to have a predetermined known positional relationship, and the incident position of the light beam from the light projecting means on the other object surface is determined by photoelectric conversion. This is determined by the conversion means, and from this the positional information of the light projecting means and the physical optical element BB is obtained. and physical optical element B
The present invention is characterized in that the position of the light projecting means is set using B, and then the positional deviation between the first object and the second object is detected.

(Example) Fig. 1 is an explanatory diagram showing the principles and structural requirements for position detection related to the position detection device of the present invention, and Figs. 2, 3 (A) and (B) are 2A and 2B are perspective views of essential parts of a first embodiment of the present invention based on the configuration shown in FIG. 1, respectively; FIG.

First, a method for detecting the relative positions of the first object and the second object will be explained. In the figure, 1 is the first object, 2 is the second object,
1 to 3 show the case of detecting the amount of relative positional deviation between the first object 1 and the second object 2. FIG. 5 is the first object 1
3 is an alignment mark provided on the second object 2 for obtaining the first signal. Similarly, 6 is an alignment mark provided on the first object 1, and 4 is an alignment mark provided on the second object 2, for obtaining the second signal light.

A linear grating 100 is provided near the alignment marks 5 and 6 on the surface of the first object 1, and deflects an incident light beam from a pickup casing 16, which will be described later, perpendicularly toward the second object 2. .

101 is a reference member, and a wafer stage 17
A physical optical element 3a is fixedly installed on a surface, and has a photoelectric conversion means 102 for detecting the incident position of a light beam as described later, and a physical optical element 3a having the same optical function as the alignment marks 3 and 4.

4a is provided. The linear grating 100 and the reference member 101 form the pickup housing 1 as described later.
The relative positional relationship between the light projecting means in 6 and the first object 1 is detected.

Each alignment mark 3, 4, 5.6 has the function of a physical optical element with or without a one-dimensional or two-dimensional lens effect, and is provided at four locations in the pattern area. 9 is a wafer scribe line, and 10 is a mask scribe line. Ll is the incident light flux.

7.8 is the first and second alignments described above.
A second signal beam is shown. 11 and 12 are first and second detection units for detecting the first and second signal beams, respectively. Second
For convenience of explanation, the optical distance from the object 2 to the first or second detection unit 11 or 12 will be described. The distance between the object 1 and the second object 2 is g, the focal lengths of the alignment marks 5 and 6 are fal and fa2, respectively, the relative positional deviation between the first object 1 and the second object 2 is Δσ, and the first ．． Second detection unit 1
Let S1 and S2 be the amount of displacement from the coincident state of the first and second signal beam centers of gravity of 1°12, respectively. Note that the alignment light flux incident on the first object 1 is assumed to be a plane wave for convenience, and the signs are as shown in the figure.

The displacement amount 51 and S2 of the center of gravity of the signal beam are the focal points F, , F2 of the alignment marks 5 and 6 and the alignment mark 3,
A straight line Ll connecting the optical axis centers of No. 4.

It is approximately determined geometrically as the intersection between F2 and the light-receiving surfaces of the detection units 11 and 12. Therefore, as is clear from FIG. 1, the amount of displacement S, S2 of the center of gravity of each signal beam with respect to the relative positional deviation between the first object 1 and the second object 2 is the optical imaging magnification of the alignment marks 3 and 4. By reversing the signs, the directions are opposite.

Also, quantitatively, it can be expressed as L-fa+"g S1=-□Δ0 : fl.-g L"-f a2"g S2=-□Δσ f -2-g, and the sliding magnification is β+ =5+/Δσ, β2 =S
It is defined as 2/Δσ. Therefore, if the shift magnification is set to have an opposite sign, the light fluxes 7 and 8 will be
change in opposite directions on the light-receiving surfaces of the detection units 11 and 12, specifically, over distances St and S, respectively.

In the upper part of FIG. 1, the light beam incident on the alignment marker 5 is made into a condensed light beam, and the light beam is irradiated onto the alignment mark 3 before reaching the condensing point F1. I'm making an image. The focal length f of the alignment mark 3 at this time is determined to satisfy the lens formula %. Similarly, in the lower part of FIG. 1, the alignment mark 6 changes the incident light flux into a light flux that diverges from the point F2 on the incident side, and this is imaged on the second detection unit 12 via the alignment mark 4. .

The focal length fb2 of the alignment mark 4 at this time is determined to satisfy. Under the above configuration conditions, the imaging magnification for the condensed images of alignment mark 3 and alignment mark 5 is clearly positive as shown in the figure, and the second object 2
The directions of the deviation amount Δσ and the light spot displacement amount S1 of the first detection unit 11 are opposite, and the deviation magnification β1 defined earlier becomes negative. Similarly, the imaging magnification of the alignment mark 4 with respect to the point image (virtual image) of the alignment mark 6 is negative, and the deviation amount Δσ of the second object 2 and the direction of the light spot displacement amount S2 on the second detection unit 12 are in the same direction. Then, the shift magnification β2 is positive.

Therefore, the first object 1 and the second object 2. With respect to the relative deviation amount Δσ, the signal beam deviation amounts S, , S2 of the system of alignment marks 5, 3 and the system of alignment mark 6.4 are in opposite directions.

That is, considering the state in which the first object 1 is fixed spatially and the second object 2 is displaced toward the bottom of the drawing in the arrangement shown in FIG. The interval between the spots widens, and conversely, when the spots are moved upward in the drawing, they appear to be sandwiched between them.

Next, FIGS. 2 and 3 (A) showing the peripheral parts of the apparatus when the present invention is applied to a proximity type semiconductor manufacturing apparatus,
Each component of (B) will be explained.

In the figure, 13 is a light source, 14 is a collimator lens (or beam diameter conversion lens), 15 is a projection light beam bending mirror, 16 is a pickup housing, 17 is a wafer stage, 2
3 is a signal processing device, 19 is a wafer stage drive control unit including a length measuring device, and E is the exposure beam width. light source 13,
The collimator lens 14 constitutes a part of the light projecting means.

In addition, in order to correspond to changes in the position of the alignment mark corresponding to each process, a drive control unit is provided inside the pickup housing 16, which has a movable mechanism and includes a length measuring device (not shown) for positioning the mechanism. Ill.

Further, 1 is a first object, for example, a square. 2 is a second object, for example a wafer to be aligned with the mask 1;

Each alignment mark 5, 6 and 3.4 consists of a crete lens, such as a one-dimensional or two-dimensional Fresnel zone plate, respectively, on one side of the mask and on one side of the wafer 2.
It is provided on the scribe lines 10 and 9 on the surface.

Reference numeral 7 denotes a first light beam, and 8 a second light beam. These light beams (signal light beams) 7 and 8 are collimated into a predetermined beam diameter by the lens system 14 out of the light beam L1 emitted from the light source 13.
The optical path is bent by the mirror 15 and the alignment mark 5 (
6) and 3(4) are shown.

In this example, a semiconductor laser (LD) is shown as the type of light source, but there are also light sources that emit a coherent light beam such as an H-Ne laser and an Ar laser, and light sources that emit a non-coherent light beam such as a light emitting diode. A light source that
A light source with intermediate characteristics such as L D ) may also be used.

In addition, the first detection section 11 and the second detection section 12 are one sensor (photoelectric conversion element) 22 in this figure, which is composed of, for example, a one-dimensional CCD or the like that receives the light beams 7 and 8.

Here, the projected light beam L1 enters the alignment marks 5 and 6 on the mask 1 surface at a predetermined angle, and then is transmitted and diffracted,
Further, the light is reflected and diffracted by the alignment mark 3.4 on the wafer 2 surface, is focused by the light receiving lens 21, and is incident on the light receiving surface of the sensor 22. In addition, in FIG. 3(A), the light receiving lens 2
1 is omitted. Then, the signal processing device 23 that receives the signal from the sensor 22 detects the center of gravity position within the sensor 22 surface of the alignment light flux that has entered the sensor 22 surface,
The signal processing device 2 uses the output signal from the sensor 22.
In step 3, positional deviation detection between the mask 1 and the wafer 2 is performed.

Here, the center of gravity of the light beam is the point in the cross section of the light beam where the integral value becomes 0 vector when the product of the position vector of each point of the cross section circle from that point multiplied by the light intensity of that point is integrated over the entire cross section. However, as another example, the position of the point where the light intensity is at its peak may be used.

Next, a specific numerical example of this embodiment will be explained.

The alignment marks 3, 4, 5.6 consist of Fresnel zone plates (or grating lenses) each having a different value of focal length.

The dimensions of these marks are scribe lines 9 and 1, respectively.
Practically appropriate sizes are 50 to 300 μm in the 0 direction and 20 to 100 μm in the scribe line width direction (X direction).

In this embodiment, each of the projected light beams 7 enters the mask 1 at an incident angle of about 17.5 degrees, and the projected component onto the mask 1 surface is perpendicular to the scribe line direction (X direction).

The projected light beams L1 incident on the mask 1 at these predetermined angles are converged or diverged by the lens action of the grating lenses 5 and 6, and the chief ray from the mask 1 is at a predetermined angle with respect to the normal line of the mask 1. The light is emitted so that

The light beams 7 and 8 transmitted and diffracted through the alignment marks 5 and 6 have a convergence point and a divergence origin at predetermined points vertically below and above the surface 2, respectively. The focal lengths of alignment marks 5 and 6 at this time are 214.723 μm and 15 μm, respectively.
It is 6.57 μm. Further, the distance between the mask 1 and the wafer 2 is 30 μm. The first signal beam 7 is transmitted and diffracted by the alignment mark 5, and the first signal beam 7 is transmitted and diffracted by the alignment mark 3 on the wafer 2 surface.
The light is subjected to the action of a concave lens and is focused on one point on the surface of the sensor 22. At this time, the amount of change in the incident position of the light beam onto the surface of the sensor 22 corresponds to the amount of positional deviation of the alignment mark 5°3 in the X direction, that is, the amount of axial deviation, and the amount is expanded. It becomes incident. As a result, the sensor 22 detects a change in the position of the center of gravity of the incident light beam.

Further, the second signal light beam 8 is transmitted and diffracted by the alignment mark 6, and is reflected and diffracted by the alignment mark 4 on the wafer 2 surface so as to move in a direction that matches the spot position of the first signal light beam at the imaging point. The light is focused on one point on the 2922-plane. Like the light beam 7, the amount of variation in the incident position of the light beam 8 corresponds to the amount of axis deviation, and is in an enlarged state. Also luminous flux 7
．． The appropriate diffraction direction of No. 8 is about 7° to 13° on the incident light side.

At this time, if the position of the light-receiving surface of the sensor 22 where the light beams 7 and 8 are focused is set at 18.657 mm from the wafer surface or at an equivalent position through the light-receiving lens 21, each shift magnification (=sensor robot spacing The direction can be set in the opposite direction by multiplying the absolute value of change/mask, wafer shift amount) by 100 times, and the combination becomes 200 times. This allows mask 1 and wafer 2 to
When the light beam shifts by o, oos μm in the X direction, the interval between the barycenters of the two light beams, that is, the spot interval changes by 1 μm.

By detecting this spot interval, a positional deviation between the mask 1 and the wafer 2 is detected. At this time, the spot diameter on the sensor 22 surface is 20 times the effective diameter of the alignment mark as a lens.
If it is about 0 μm and a 0.8 μm band semiconductor laser is used as a light source, it can be set to about 200 μm, and it is possible to determine this using a normal processing technique. In addition, it is appropriate to set the spacing between the two spots to about 2 mm in the matched state, for example.

Next, the reference member 10 shown in FIGS. 3(A) and 3(B)
1 will be explained.

In this embodiment, the reference member 101 is fixed to a part of the surface of a wafer stage 17 that is substantially integral with the wafer, which is the second object 2.

FIG. 4 is a schematic diagram of the main parts of the reference member 101 in this embodiment.

As shown in the figure, a reference member 101 includes a photoelectric conversion means 102 consisting of four pixels (elements) 102a to 102d, such as a pin photodiode or a CCD, and an alignment mark consisting of a physical optical element on the second surface of the second object described above. It has physical optical elements 3a and 4b which have optical functions substantially equivalent to those of physical optical elements 3 and 4.

Then, as shown in FIG. 3(A), the reference member 10
After the second object 2 (wafer) is placed on the wafer stage 17 and the second object 2 (wafer) is chucked onto the wafer stage 17, they are integrally set so that their relative positions do not change.

Further, the photoelectric conversion means 102 and the physical optical elements 3a and 4a are manufactured by a normal semiconductor process, and their relative positions are known within, for example, about 0.1 μm due to the accuracy of a photomask created with an electron beam and a reduction projection exposure device. It has become.

Now, from the center of the physical optical elements 3a, 4a, the photoelectric conversion means 1
Let the distance to the center of 02 be (x, y). Further, the photoelectric conversion efficiency of the four pixels 102a to 102d of the photoelectric conversion element 102 can be made uniform or corrected by ordinary means, and can be considered to be uniform here.

Next, a method of detecting the relative position between the light projecting means and the first object 1, which is a feature of this embodiment, will be explained.

First, the pickup casing 16 is moved, and the projected light beam from the pickup casing 16 is projected onto the linear grating 1 provided on the mask 1 surface.
00, and the position pressure of the pickup casing 16 at this time! Record (x,y)pa. At this time, the linear grating 100 is approximately set to have a wide area that can sufficiently cover the projected light beam, taking into consideration the absolute positioning accuracy of the pickup housing 16. FIG. 5 is a schematic diagram showing this situation.

In addition, the pitch of the linear grating 100 is set according to the incident angle and wavelength of the projected light beam so that the diffracted light beam is vertically emitted from the first object 1 to the second object 2 side in order to eliminate the influence of positioning errors in two directions of the stage 17. are doing.

Next, the wafer stage 17 is moved so that the diffracted light beam from the linear grating 100 is incident approximately onto the photoelectric conversion means 102 on the surface of the reference member 101. Here, the output signals from the pixels 102a to 102d of the photoelectric conversion means 102 are respectively A.

B, C, D and A + B) - (C + D) = O and (A +
D)-(C+B)=0 or A+C)-(B+D)=
The reference member 101 is set by moving the wafer stage 17 so that the position becomes O. The coordinates of the wafer stage 17 at this time are (X.

y), , o'.

From this, the positional relationship between the photoelectric conversion means 102 and the pickup housing 16 is specified. And pickup housing 1
In order to align the alignment marks 3a and 4a with the diffracted light from the linear grating 100 of the projected light beam from 6, the wafer stage 17 on which the reference member 101 is placed is
Move by ')ro'-(ma, y) while referring to the length measuring device 19. The positional coordinates of the physical optical elements 3a and 4a of the reference member 101 at this time are (X, y)ro.

As described above, the position coordinates (X
, y) Po and the center position coordinates (x.

y) Ro's reincarnation is completed.

Next, referring to the length measuring device provided in the pickup housing 16, the pickup housing 16 is moved so that the center of the projected light beam is moved approximately to the center of the alignment mark 5.6. At this time, the wafer stage 17 on which the reference member 101 is placed also moves the same amount as the pickup housing 16 at this time.
amount and move in the same direction.

Here, the amount of positional deviation Δσ is determined based on the principle of detecting the amount of relative positional deviation between the first object 1 and the second object 2 described above. Subsequently, the pickup housing 16 and the reference member 101 are moved by Δσ. At this time, the amount of relative positional deviation between the alignment mark 5.6 and the physical optical elements 3a, 4a approaches the true value of 0. The relative positional deviation detection and the integral movement of the pickup casing 16 and the reference member 101 are repeated again and converged, thereby completing the alignment of the alignment mark 5.6 and the physical optical elements 3a, 4g. At the same time, the pickup housing 16 and the physical optical element 3a.

4a has been completed, it means that the alignment between the alignment mark 5.6 and the projection light beam has been completed.

After installing the pickup housing 16 in this manner, align the wafer stage 1 with the alignment marks 3 and 4 on the second object positioned approximately below the alignment mark 5.6.
Move 7.

Hereinafter, in this embodiment, the first object 1 and the second object 2 are aligned based on the above-mentioned relative positional deviation detection principle.

In this embodiment, the photoelectric conversion means 102 has been described as having four pixels for convenience, but of course, when it is necessary to perform detection in only one direction, a structure of two pixels arranged in the detection direction may be used. Alternatively, the center of gravity position of the projected light beam may be determined by processing such as center of gravity calculation using a two-dimensional area sensor composed of a large number of pixels used in ordinary TV cameras as the photoelectric conversion means 102, or direct light spot position information may be used. For example, a PSD (position sensing device), etc., which can output , may be used.

In this embodiment, the projected light beam from the pickup housing 16 is assumed to be obliquely incident light at an angle of 17.5°, and the angle at which the beam is transmitted through and diffracted through the alignment marks 5 and 6 of the first object 1 is used as a characteristic for perpendicular output to the first object. However, as is clear from the detection principle, these can be set arbitrarily in terms of design. For example, as a special example of this, a system may be used in which the projected light beam is perpendicularly incident on the first object 1. In this case, the linear grating 100 provided on one surface of the mask has an infinite pitch, that is, a plain pattern. In other words, the linear grating 100 can be made unnecessary.

Furthermore, for convenience, the linear grating 100 and the alignment marks 5 and 6 are provided on the first object surface 1 in the explanation, but as is clear from the procedure for setting the pickup housing 16, the linear grating 100 and the alignment marks 5 and 6 are provided on the first object surface 1 at the beginning. After determining the position (x, y)-o of the reference member 101, the first object 1 is replaced with a different object to be aligned (i.e., a normal photomask), and the same process is performed as follows. The positioning of both may be performed in a procedure.

(Effects of the Invention) According to the present invention, a linear grating as described above is provided on the first object plane, and diffracted light of a predetermined order generated from the linear grating is transferred to the second object plane.
By detecting with a reference member provided on the object side, the positional relationship between the light projecting means and the first object or the positional relationship between the light projecting means and the second object is detected.
Since the positional relationship with the object can be appropriately set, it is possible to achieve a position detection device that can perform later relative position detection between the first object and the second object with high precision.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the principle of position detection by the position detection device of the present invention, and FIGS. 2, 3 (A), and (B) are outlines of essential parts of an embodiment of the present invention based on FIG. 1. Figures 4 and 5 are detailed explanatory diagrams of the present invention, and Figure 6 is a schematic diagram of a luminous flux emitted from a conventional laser. In the figure, 1 is the first object, 2 is the second object, 3 and 4° 5.6 are alignment marks, 100 is a linear grating, 101 is a reference member, Ll and L2 are light fluxes, and 7 and 8 are signal light fluxes, respectively. , 11 is a first detection section, 12 is a second detection section, 13 is a light source, 14 is a collimator lens, 15 is a mirror, 22
is a sensor. Figure 2 Figure 3 (A) Figure 4 Figure 5

Claims (3)

[Claims] (1) When performing relative position detection with a first object and a second object facing each other, physical optical elements are formed on the first object surface and the second object surface, respectively, and one of the physical optical elements is formed on the first object surface and the second object surface. Diffraction light generated when light is incident on the physical optical element A on the object plane from the light projecting means is made incident on the physical optical element B on the other object plane,
When detecting the relative positions of the first object and the second object by detecting the light flux position of the diffraction pattern generated on a predetermined surface by the physical optical element B, the other object surface is detected. A physical optical element BB having an optical action equivalent to the physical optical element B on the object surface that is substantially integrally formed with the upper or the other object, and an incident position of the light beam from the light projecting means. A photoelectric conversion means capable of detecting is provided, and the position of the light projecting means and the physical optical element A is set using the photoelectric conversion means and the physical optical element BB. Position detection device. (2) A linear grating is provided on the one object surface, and after the light beam from the light projecting means is deflected via the linear grating, it is made to enter the photoelectric conversion means. Item 1. Position detection device according to item 1. (3) The position detection device according to claim 2, wherein the photoelectric conversion means and the physical optical element BB are formed so that a relative positional relationship has a known predetermined value.