JP2002231616A - Instrument and method for measuring position aligner and method of exposure, and method of manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an instrument and method for position determination with which the throughput of position measurement can be improved, by shortening the time required for the measurement of positional information, without lowering measurement accuracy, and to provide an aligner and method for exposure and a method of manufacturing device. SOLUTION: Relation between a deviated amount Δ of a wafer W in the Z-axis direction from the focal point of alignment sensors (13-39) and a positional deviated amount ΔX of an alignment mark AM in the X-Y plane, corresponding to a deviated amount ΔZ is prestored in a storage device 40. At the measuring of the positional information on the mark AM, the deviated amount ΔZ of the wafer W in the Z-axis direction from the focal point of the alignment sensors (13-39) is detected, and the positional information on the mark AM is found, by correcting the positional information of the mark AM measured by means of the sensors (13-39), based on the detected deviated amount ΔZ and the relation stored in the storage device 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position measuring apparatus and a position measuring method for measuring position information of a mark formed on an object such as a substrate or a reticle in a process of manufacturing a device such as a semiconductor element or a liquid crystal display element. An exposure apparatus and method for performing alignment (alignment) between a substrate and a reticle based on position information measured using a measurement apparatus and method, and transferring an image of a predetermined pattern formed on the reticle onto the substrate, and an exposure apparatus and method. The present invention relates to a device manufacturing method for manufacturing a device using an exposure method.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, liquid crystal display devices, and the like, an image of a fine pattern formed on a photomask or a reticle (hereinafter, these are collectively referred to as a reticle) by using an exposure apparatus is used for forming a photoresist or the like. Transfer onto a semiconductor wafer or a glass plate coated with a photosensitive agent is repeatedly performed. Especially in the manufacture of semiconductor devices,
A step-and-repeat type reduction projection type exposure apparatus (so-called stepper) is often used as the exposure apparatus. When transferring the image of the pattern, it is necessary to precisely match the position of the substrate with the position of the pattern image formed on the reticle to be transferred. In particular, in the production of a semiconductor device, the pattern must be accurately overlapped several times to several tens of times, but the pattern formed in recent years is fine, and a semiconductor device having desired performance is produced. For this reason, it is required to improve the accuracy of alignment. Marks for measuring the positions of the substrate and the reticle are formed, and the exposure apparatus includes a position measuring device that measures the position information of the reticle or the substrate by measuring the position information of these marks.

[0003] Among the position measuring devices, a reticle position measuring device for measuring reticle position information generally uses exposure light for exposing a substrate as a light source. The measurement method of this reticle position measurement device includes, for example, VRA
(Visual Reticle Alignment) method. In the VRA method, an optical image obtained by irradiating exposure light on a mark formed on a reticle is converted into an image signal by an image pickup device such as a CCD (Charge Coupled Device) before the substrate is transferred onto a stage, The image processing of the image signal is performed to measure the position information of the mark.

[0004] Among the position measuring devices, the substrate position measuring device that measures the positional information of the substrate changes the surface state (roughness) of the substrate to be measured in the process of manufacturing a semiconductor element or a liquid crystal display element. Therefore, it is difficult to accurately measure the position information of the substrate using a single type of device,
Generally, different types of apparatuses are used according to the surface condition of the substrate. The main ones of these devices are LS
A (Laser Step Alignment) method, FIA (Field Imag)
e Alignment) method, LIA (Laser Interferometric A)
lignment) method.

The following is a brief description of these types of substrate position measuring devices. That is, the LSA type substrate position measuring device is a substrate position measuring device that irradiates a mark formed on a substrate with a laser beam and measures the position information of the mark by using diffracted / scattered light. Is widely used for semiconductor wafers in various manufacturing processes. The FIA type substrate position measuring device illuminates a mark using a light source having a wide wavelength band such as a halogen lamp, converts an image of the resulting mark into an image signal, and performs image processing to measure the position. This is a substrate position measurement device that performs measurement of an asymmetric mark formed on an aluminum layer or a substrate surface. The LIA-type substrate position measuring device irradiates laser beams having slightly different wavelengths from two directions onto diffraction grating marks formed on the substrate surface, and causes the resulting two diffracted lights to interfere with each other. This is a substrate position measurement device that measures mark position information from the phase of the mark.
The LIA type substrate position measuring device is effective when used for a substrate having a low step mark or a large substrate surface roughness.

Further, as the position measuring device, there is provided a T position measuring device for measuring position information of a mark on a substrate via a projection optical system.
The TL (through-the-lens) method, the off-axis method of directly measuring the position information of the mark on the substrate without passing through the projection optical system, and the observation of the substrate and the reticle simultaneously via the projection optical system, T that measures the relative positional relationship of
There is a TR (through the reticle) method. When aligning the reticle with the substrate using these position measuring devices, the exposure device uses a mark formed on the substrate in advance and a plurality of defined regions (shot regions) set on the substrate. The positional relationship is stored, and a baseline amount, which is the distance between the measurement center of the position measurement device and the center (center of exposure) of the projected image of the reticle pattern, is obtained. Then, the position measuring device measures the amount of deviation of the mark from the measurement center, and moves the substrate by a distance obtained by correcting the amount of deviation with the baseline amount, so that a plurality of divided areas (shot areas) set on the substrate are obtained. After the center of the shot is accurately aligned with the center of exposure, the shot area is exposed by exposure light.

[0007] Among the above-mentioned position measuring devices, the LIA type position measuring device and the LSA type position measuring device are TTL for measuring the position of a mark on a substrate via a projection optical system.
Is often used as a position measuring device of the TIA method or the TTR method, and the position measuring device of the FIA method is often used as a position measuring device of an off-axis method. Therefore, the LIA-type position measurement device and the LSA-type position measurement device mainly use a laser beam of a single wavelength to avoid chromatic aberration of the projection optical system. However, since a photoresist having a thickness of about 0.5 μm to 2 μm is usually applied on the substrate, interference fringes are generated in the photoresist when a single-wavelength laser beam is used. May be wrong.

When the position measuring device of the FIA system is mounted as an off-axis system, the light irradiated to the mark does not pass through the projection optical system, so that it is not necessary to consider the chromatic aberration in the projection optical system. Light sources with a wide bandwidth can be used. When a light source having a wide wavelength bandwidth is used, an interference effect generated when a laser beam having a single wavelength is used can be reduced, and position information of a mark can be detected with high accuracy. Since the FIA type position measuring device has a wide wavelength bandwidth of illumination light, the imaging optical system of the position measuring device is designed to correct chromatic aberration with respect to the illumination light.

[0009]

Considering the case where the FIA type position measuring device is mounted as an off-axis type, the image forming optical system of the position measuring device is designed so that chromatic aberration is removed as described above. Although the design and adjustment have been made, aberrations other than chromatic aberration (for example, coma and astigmatism) remain. Further, the imaging optical system of the position measuring device usually constitutes a telecentric optical system. Therefore, when the mark formed on the substrate is displaced from the focal position of the position measuring device, the position of the mark in the substrate surface is laterally shifted according to the deviation amount of the mark from the focal position in the direction perpendicular to the substrate. Measurement is performed, a measurement error occurs. Conventionally, after detecting the amount of deviation from the focus position of the position measuring device in advance so that this lateral deviation does not occur, the position of the substrate in the substrate vertical direction is adjusted based on the detection result, and then the mark in the substrate surface is I was measuring location information.

In recent years, not only in the manufacture of semiconductor elements, but also in the manufacture of various devices, it has been required to set the number of processes per unit time, that is, the throughput high, and this demand is increasing year by year. Increasing the throughput means reducing the time required for processing one substrate. Therefore, it is necessary to reduce unnecessary processing as much as possible in processing the substrate.

As described above, conventionally, when measuring the position information of a mark formed on a substrate using a position measuring device, the amount of deviation of the mark from the focal position of the position measuring device is detected once. After the detection, the substrate position in the direction perpendicular to the substrate surface is adjusted to measure the position information of the mark in the substrate surface. Therefore, there is a problem that the throughput is not improved. In particular, in the manufacture of a semiconductor device, a plurality of shot regions are formed on one substrate, and a mark is formed for each of the shot regions. Therefore, the number of marks to be measured by the position measurement device is large, and the throughput is reduced accordingly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and can reduce the time required for measuring position information without deteriorating the measurement accuracy, thereby improving the throughput. , Exposure apparatus and method,
Another object of the present invention is to provide a device manufacturing method.

[0013]

In order to solve the above-mentioned problems, a position measuring apparatus according to a first aspect of the present invention provides a position measuring device for a mark (AM, AM _X , AM _Y ) formed on an object (W). The position information in the two-dimensional plane (XY plane) is converted into position measurement optical systems (13, 1) including objective optical systems (18, 19).
4, 15, 16, 17, 18, 19, 20, 21, 2,
2, 23, 24, 25, 26, 27) and a position measuring means (28) for measuring through the objective optical system (18, 1).
9) and the position measurement optical system (13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24, 2
5, 26, 27), and the two-dimensional plane (X
A focus detection optical system (16, 17, 18, 19, 19) having a focus position in a direction (Z-axis direction) perpendicular to the Y plane
20, 21, 22, 23, 30, 31, 32, 33, 3
4, 35, 36, 37, 38), and the matching state between the in-focus position and the object (W) is determined by the focus detection optical system (16, 17, 18, 19, 20, 21, 22, 22). 23,
30, 31, 32, 33, 34, 35, 36, 37, 3
8) a focus detection means (39) for detecting the change in the alignment state and a change in the position information; and a storage means (40) for storing the relationship between the change in the alignment state and the change in the position information. The mark (AM, AM) based on the obtained relationship and the measurement value measured by the position measurement means (28).
AM _X, is characterized by obtaining the position information within said two-dimensional plane (XY plane) of the AM _Y). According to the present invention, the relationship between the change in the state of alignment between the focus position of the focus detection optical system and the object and the change in the position information of the mark in the two-dimensional plane according to this change is stored in the storage means in advance. In addition, when measuring the position information of the mark, by the position measuring means based on the change of the matching state between the detected focus position of the focus detection optical system and the object and the relationship stored in the storage means, The position information of the mark in the two-dimensional plane is obtained by correcting the measured position information. Therefore, even if the object is shifted from the in-focus position of the focus detection optical system, or the position measurement optical system is left with aberrations such as coma and astigmatism, and the position information is measured in a state where the mark is laterally shifted, Since the position information in which the lateral displacement has been corrected can be obtained, the position information of the mark in the two-dimensional plane can be measured without lowering the measurement accuracy. Further, the position measuring device according to the second aspect of the present invention is the position measuring device according to the first aspect, wherein the storage means (4
0) is the vertical direction (Z-axis direction) including the focus position
And storing the position information when the object (W) is present at each of a plurality of vertical positions within the predetermined range in association with the change in the vertical position and the change in the position information. . According to the present invention, since the storage device stores the change in the vertical position of the object and the change in the position information in a predetermined range of the vertical method including the focus position of the focus detection optical system in association with each other, the focus detection optical system is used. Even if the absolute value of the shift amount in the Z-axis direction and the absolute value of the shift amount in the -Z-axis direction with respect to the focusing position of the system are equal, the absolute value of the shift amount of the position information in the two-dimensional plane is different (this phenomenon is mainly This is a phenomenon caused by aberrations), and the position information can be measured without lowering the accuracy of the position information. Further, the position measuring device according to a third aspect of the present invention is the position measuring device according to the first aspect or the second aspect, wherein the object (W) is placed in the vertical direction (Z-axis direction) with the object (W) mounted thereon. A movable stage (7), and a detecting means (12) for detecting a change in a value measured by the position measuring means (28) accompanying the movement of the stage (7) in the vertical direction (Z-axis direction). Has,
The storage means (40) stores a detection result by the detection means (12). According to the present invention, since the change in the measurement value of the position measurement means is stored in the storage means while the stage on which the object is mounted is moved in the vertical direction, the focus position of the focus detection optical system can be shortened in a short time. , And the relationship between the change in the vertical position of the object with respect to and the change in the position information of the mark in the two-dimensional plane can be continuously obtained. The position measuring device according to a fourth aspect of the present invention is the position measuring device according to the third aspect, wherein the position measuring means (28) is mounted on the stage (7) when the detecting means (12) performs detection. It is characterized by measuring the position information of the reference mark (8) provided in. According to the present invention, at the time of detection by the detecting means, the reference mark provided on the stage is measured to change the vertical position of the object with respect to the focus position of the focus detection optical system and to determine the position information of the mark in the two-dimensional plane. Since the relationship with the change is obtained, the amount of lateral displacement in a two-dimensional plane caused by the deviation from the focus position of the focus detection optical system and the aberration remaining in the position measurement optical system is determined by a mark formed on the object. Can be obtained without being affected by the shape of. A position measuring device according to a fifth aspect of the present invention is the position measuring device according to the third aspect, wherein the position measuring means (28) is mounted on the stage (7) upon detection by the detecting means (12). It is characterized by measuring the position information of the mounting has been that the object (W) is formed on the mark _{(AM, AM X, AM Y} ) to. According to the present invention, at the time of detection by the detection means, the mark formed on the object is measured, and the change in the vertical position of the object with respect to the focus position of the focus detection optical system and the change in the position information of the mark in the two-dimensional plane are measured. And the amount of lateral displacement in a two-dimensional plane caused by the deviation from the focus position of the focus detection optical system and the aberration remaining in the position measurement optical system, It can be obtained including the amount of lateral displacement generated according to the shape. Therefore, when the shape of the mark formed on the object is a shape that is likely to cause a lateral displacement in the measurement of the position information, the lateral displacement can be obtained including the influence due to the shape of the mark. It is very suitable when the position information of the mark is obtained by using. Further, the position measuring device according to a sixth aspect of the present invention is the position measuring device according to the fifth aspect, wherein the object (W) is a substrate having a plurality of substrates subjected to a predetermined process and having a set of lot units. And the detection means (12) performs the detection on at least the first substrate of the lot. According to the present invention, a relationship between a change in a vertical position of an object with respect to a focus position of a focus detection optical system and a change in position information of a mark in a two-dimensional plane is determined for a plurality of substrates in lot units. At the time, detection is performed on the first substrate of the lot or several substrates at the beginning of the lot, and for the remaining substrates in the lot, the position of the mark measured based on the detection result of the detected substrate The information is corrected. Therefore, the processing for obtaining the relationship between the change in the vertical position of the object with respect to the focus position of the focus detection optical system and the change in the position information of the mark in the two-dimensional plane is not performed on these remaining substrates. Measurement time can be reduced. A position measuring device according to a seventh aspect of the present invention is the position measuring device according to the sixth aspect, wherein a plurality of the marks (AM, AM _X , AM _Y ) are formed on the substrate (W). The detecting means (12) is adapted to detect the plurality of marks (AM, A
M _X, found for the AM _Y), detecting a change in said measurement value due to the movement in the vertical direction (Z axis direction) of the stage (7), said storage means (40), said mark ( A
M, AM _X , AM _Y ), and stores the average value of the change in the measured value in association with the movement in the vertical direction (Z-axis direction). According to the present invention, when detection is performed on the first substrate of a lot or on several substrates at the beginning of a lot, a change in a measurement value accompanying movement of the stage in the vertical direction is obtained for each of a plurality of marks, and an average thereof is obtained. The value is stored in the storage means, and for the remaining substrates in the lot, the position information of the mark measured based on the average value stored in the storage means is corrected. Substrates that have been subjected to substantially the same processing are provided in the same lot, the surface condition of each substrate is substantially the same, and the situation in which the lateral shift amount of each mark is completely different even within the substrate does not often occur. However, if the correction is performed based only on the measurement result obtained from one substrate, high reliability may not be obtained, for example, when the surface state of the substrate that is accidentally measured is poor. Therefore, it is preferable to obtain the average value for each mark to improve the reliability and reduce the time required for measuring the position information without lowering the measurement accuracy. Also,
The position measuring device according to the eighth aspect of the present invention provides an object (W)
In a position measuring device for measuring position information of a mark (AM, AM _X , AM _Y ) formed on a two-dimensional plane (XY plane), a direction perpendicular to the two-dimensional plane (XY plane) ( Focus detection optical system (16, 17, 18, 19, 20, 21, 2, 2) having a focus position in the Z-axis direction)
2, 23, 30, 31, 32, 33, 34, 35, 3,
6, 37, 38) focus detection means (39) for detecting the state of alignment between the in-focus position and the object (W)
A position measuring means (28) for measuring position information of the mark (AM, AM _X , AM _Y ) in the two-dimensional plane (XY plane); A stage (7) that moves in a two-dimensional plane (XY plane) and in the vertical direction (Z-axis direction); and a stage (7) based on the alignment state detected by the focus detection means (39). Control means for controlling the stage (7) and the position measuring means (28) so as to perform the measuring operation by the position measuring means (28) without moving the stage (7) (direction). 12). According to the present invention, even when an object is vertically displaced from the focus position of the focus detection optical system, measurement is performed in a state where the object is displaced from the focus position without moving the stage. The control means controls the stage and the position measuring means to perform the operation. Therefore, since the control for arranging the object at the focal position of the focus detection optical system for each mark is omitted, the time required for measuring the position information can be extremely reduced, and as a result, the throughput can be improved. In addition, the ninth aspect of the present invention
The position measuring device according to the aspect of the present invention is the position measuring device according to the eighth aspect, further comprising a storage unit (40) that stores a relationship between the change in the matching state and the change in the position information,
The two-dimensional plane (XY) of the mark (AM, AM _X , AM _Y ) based on the relationship stored in the storage means (40) and the measurement value measured by the position measurement means (28). It is characterized in that position information within a plane is obtained. According to the present invention, the relationship between the change in the state of alignment between the focus position of the focus detection optical system and the object and the change in the position information of the mark in the two-dimensional plane according to this change is stored in the storage means in advance. In addition, even when the object is not located at the in-focus position of the focus detection optical system, position information of the mark in the two-dimensional plane is measured by the position measurement unit, and the position information is stored in the storage unit. Correction is based on the relationship. Therefore, since the control for arranging the object at the focal position of the focus detection optical system for each mark is omitted, the time required for measuring the position information can be extremely reduced, and the position of the mark can be reduced without lowering the measurement accuracy. Information can be measured. Further, the exposure apparatus of the present invention,
Based on the above the marks obtained by any of the position measuring device of the ninth aspect of the first aspect _{(AM, AM X, AM Y} ) position information of the mark (AM, AM _X, A
M _Y ) having positioning means (11, 12) for positioning the substrate on which the positioning means (11, 12) are formed.
The method is characterized in that a predetermined pattern (PA) is transferred onto the substrate (W) positioned in 12). According to the present invention, the measurement result of the position information is obtained in a short time without lowering the measurement accuracy by the position measurement device. Based on the measurement result, the substrate is aligned and a predetermined pattern is formed on the substrate. Since the transfer is performed, the alignment can be performed with high accuracy, and the throughput can be improved. Further, the position measurement method according to the first aspect of the present invention provides a mark (AM, AM _X ,
AM _Y ) is a position measurement method for measuring position information in a two-dimensional plane (XY plane), wherein the mark (AM,
AM _X , AM _Y ) in the two-dimensional plane (XY plane) is converted into position measurement optical systems (13, 14, 15, 16, 17, 18, 1) including objective optical systems (18, 19).
9, 20, 21, 22, 23, 24, 25, 26, 2,
7), and the objective optical system (18, 19) and the position measuring optical system (13, 14, 15, 16, 17,
18, 19, 20, 21, 22, 23, 24, 25, 2,
6, 27), and has a focus position in a direction (Z-axis direction) perpendicular to the two-dimensional plane (XY plane) (16, 17, 18, 19, 2).
0, 21, 22, 23, 30, 31, 32, 33, 3
4, 35, 36, 37, 38) to detect a matching state between the in-focus position and the object (W), and store a relationship between a change in the matching state and a change in the position information; wherein said relationship being the storage, on the basis on the measured measurement value, said mark _{(AM, AM X, AM Y} ) determining the position information within said two-dimensional plane (XY plane) of And The position measuring method according to a second aspect of the present invention is the position measuring method according to the first aspect, wherein the object (W) is moved in the vertical direction (Z-axis direction) before the position information is determined. The change of the measurement value caused by the change of the alignment state due to the movement of is detected, and the relation obtained based on the detected result is stored. According to these inventions, the relationship between the change in the state of alignment between the focus position of the focus detection optical system and the object and the change in the position information of the mark in the two-dimensional plane according to this change is stored in advance in the storage means. When measuring the position information of the mark, the position measuring means is based on the change of the in-focus state between the detected focus position of the focus detection optical system and the object and the relationship stored in the storage means. The position information of the mark in the two-dimensional plane is obtained by correcting the position information measured by the method. Therefore, even if the object is shifted from the in-focus position of the focus detection optical system, or the position measurement optical system is left with aberrations such as coma and astigmatism, and the position information is measured in a state where the mark is laterally shifted, Since the position information in which the lateral displacement has been corrected can be obtained, the position information of the mark in the two-dimensional plane can be measured without lowering the measurement accuracy. In a position measurement method according to a third aspect of the present invention, in the position measurement method according to the second aspect, the relation is such that the reference mark is fixed on a stage (7) on which the object (W) is mounted. The stage (7) of the position information of (8) or the position information of the mark (AM, AM _X , AM _Y ) formed on the object (W) placed on the stage (7). Is obtained by detecting a change in the measured value accompanying the movement of the measured value in the vertical direction (Z-axis direction). According to the present invention, the reference mark provided on the stage or the mark formed in the shape of an object is measured to change the vertical position of the object with respect to the focus position of the focus detection optical system and the position of the mark in a two-dimensional plane. Seeking a relationship with changes in information. Therefore, the amount of lateral displacement in a two-dimensional plane caused by the deviation of the focus detection optical system from the in-focus position and the aberration remaining in the position measurement optical system is affected by the shape of the mark formed on the object. However, if the position information has a shape that is likely to cause a lateral displacement in the measurement of the position information, a relationship including an influence due to the shape of the mark can be obtained. Further, the position measurement method according to the fourth aspect of the present invention provides a mark (AM, AM _X ,
AM _Y ) is a position measurement method for measuring position information in a two-dimensional plane (XY plane), wherein the two-dimensional plane (X
A focus detection optical system (16, 17, 18, 19, 19) having a focus position in a direction (Z-axis direction) perpendicular to the Y plane
20, 21, 22, 23, 30, 31, 32, 33, 3
4, 35, 36, 37, 38), the matching state between the in-focus position and the object (W) is detected, and the matching state of the stage (7) on which the object (W) is placed performing the based on the detection result without performing movement in the vertical direction (Z axis direction), the mark _{(AM, AM X, AM Y} ) measurement of the position information within said two-dimensional plane (XY plane) of It is characterized by: Further, a position measuring method according to a fifth aspect of the present invention is the position measuring method according to the fourth aspect, wherein the measurement of the position information is performed after the detection of the matching state. According to these inventions, the relationship between the change in the state of alignment between the focus position of the focus detection optical system and the object and the change in the position information of the mark in the two-dimensional plane according to this change is stored in advance. Even when the object is not located at the focus position of the focus detection optical system, the position measurement means measures the position information of the mark in the two-dimensional plane, and the position information is stored in the storage means. It is corrected based on. Therefore, since the control for arranging the object at the focal position of the focus detection optical system for each mark is omitted, the time required for measuring the position information can be extremely reduced, and the position of the mark can be reduced without lowering the measurement accuracy. Information can be measured. Further, the exposure method of the present invention is based on the position information of the mark (AM, AM _X , AM _Y ) obtained by the position measurement method according to any one of the first to fifth aspects. Positioning the substrate (W) on which the marks (AM, AM _X , AM _Y ) are formed, and transferring a predetermined pattern (PA) onto the positioned substrate (W). I have. According to the present invention, the measurement result of the position information is obtained in a short time without reducing the measurement accuracy, and the predetermined pattern is transferred onto the substrate by performing the alignment of the substrate based on the measurement result. Positioning can be performed with high accuracy, and the throughput can be improved. Further, a device manufacturing method of the present invention includes a step of transferring a device pattern (PA) onto the substrate (W) using the above-described exposure method.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a position measuring apparatus and method, an exposure apparatus and method, and a device manufacturing method according to embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an exposure apparatus according to an embodiment of the present invention including a position measuring device according to an embodiment of the present invention. In the present embodiment, an example in which the present invention is applied to a step-and-repeat type exposure apparatus having an off-axis type alignment sensor as a position detection device will be described. In the following description,
The XYZ rectangular coordinate system shown in FIG.
The positional relationship between the members will be described with reference to the Z orthogonal coordinate system. In the XYZ orthogonal coordinate system, the X axis and the Z axis are set to be parallel to the paper surface, and the Y axis is set to a direction perpendicular to the paper surface. The XYZ coordinate system in the figure is
Actually, the XY plane is set to a plane parallel to the horizontal plane, and the Z axis is set vertically upward.

In FIG. 1, when the exposure light EL is emitted from an illumination optical system (not shown), the exposure light EL irradiates the pattern area PA formed on the reticle R via the condenser lens 1 with a uniform illuminance distribution. I do. The above exposure light EL
For example, g-line (436 nm) and i-line (365n)
m) or KrF excimer laser (248 nm), Ar
Light emitted from an F excimer laser (193 nm) or an F ₂ excimer laser (193 nm) is used.

The reticle R can be finely moved by the motor 2 in the direction of the optical axis AX of the projection optical system PL.
The reticle stage 3 is mounted on a reticle stage 3 capable of two-dimensional movement and minute rotation in a plane perpendicular to X. Reticle stage 3
A movable mirror 5 for reflecting the laser beam from the laser interferometer 4 is fixed to an end of the reticle stage 3.
The dimensional position is determined by, for example, 0.0
It is always detected with a resolution of about 1 μm.

The exposure light EL transmitted through the pattern area PA of the reticle R is incident on, for example, both sides (or one side) of a telecentric projection lens PL and is projected on each shot area on a wafer (substrate) W. Here, the projection lens PL is best corrected for aberration with respect to the wavelength of the exposure light EL, and the reticle R and the wafer W
And are conjugate to each other. The illumination light EL is Keller illumination, and is formed as a light source image at the center of a pupil (not shown) of the projection lens PL. Incidentally, the projection lens PL
Has a plurality of optical elements such as lenses, and the glass material of the optical elements is selected from optical materials such as quartz and fluorite according to the wavelength of the exposure light EL.

The wafer W is mounted on a wafer stage 7 via a wafer holder 6. Here, the wafer W placed on the wafer holder 6 will be described. FIG.
FIG. 3 is a top view illustrating a schematic configuration example of a wafer W. As shown in FIG. 2, on the upper surface of the wafer W, a plurality of shot areas SA1 to SAn (n is a natural number) to which an image of a pattern formed in the pattern area PA of the reticle R is transferred are in the X-axis direction and the Y-axis. They are arranged at predetermined intervals in the direction. Between each shot area AS1~SAn are formed and street line SL _Y the street line SL _X and the length direction set lengthwise direction in the X-axis direction is set in the Y-axis direction. The street lines SL _X and SL _Y are collectively referred to as a street line SL.

FIG. 3 is a top view showing the configuration near one shot area. In FIG. 3, the shot area SA
k (k is a natural number) and the alignment mark AM _X for X-axis direction measurement in response to is formed on the street line SL _X, formed in the Y-axis direction alignment mark AM _Y for measuring street on line SL _Y Have been. These alignment marks AM _X, in the case of collectively collectively AM _Y is referred to as the alignment mark AM. In the example shown in FIG. 3, the alignment mark AM and the straight line parallel to the street Y axis the center point in the X-axis direction of _X, the alignment mark AM _Y of parallel as X axis the center point in the Y-axis direction line intersection between the so as to be positioned in the center point of the shot area SAk, shot area SAk and the alignment mark AM _X, AM _Y is set.

In FIG. 3, an alignment mark A called a one-dimensional line and space mark is provided.
M _X, are illustrated the AM _Y, may be used an alignment mark AM in a single measurement in a 2-dimensional measurement both can be obtained between the position information and the Y-axis direction position information of the X-axis direction . FIG. 4 shows an alignment mark AM for two-dimensional measurement.
It is a top view which shows the example of a structure. The alignment mark AM for two-dimensional measurement shown in FIG. 4 measures position information in the X-axis direction in which mark elements am1 whose longitudinal directions are set in the Y-axis direction are arranged at regular intervals in the X-axis direction. And a part for measuring position information in the Y-axis direction, in which mark elements am2 whose longitudinal directions are set in the X-axis direction are arranged at regular intervals in the Y-axis direction. By measuring the position information in the X-axis direction and the position information in the Y-axis direction at one time by using the alignment mark AM for two-dimensional measurement, the alignment mark formed on the street line SL is measured. The number can be reduced, and the time required for measurement can be shortened, which is preferable in achieving high throughput.

Returning to FIG. 1, on the wafer stage 7, a reference member 8 having a reference mark used for measuring a baseline and an amount of lateral displacement of a mark with respect to a displacement of a focal position of an alignment sensor described later is provided. Have been.
The position of the reference member 8 in the Z-axis direction is set to substantially the same position as the surface position of the wafer W in the Z-axis direction. As reference marks, a slit pattern composed of five sets of light-transmissive L-shaped patterns and two sets of reference patterns formed of light-reflective chrome (duty ratio is 1:
1) is provided.

One set of reference patterns has a diffraction grating mark in which seven dot marks arranged in the Y direction are arranged in three rows in the X-axis direction, and three linear patterns are arranged in the X-axis direction. And 12 bar marks extending in the Y direction are arranged in the X axis direction. The other set of reference patterns is obtained by rotating the one set of reference patterns by 90 °. Exposure light is guided to the reference member 8 from below using an optical fiber (not shown) or the like so that the slit pattern formed on the reference member 8 is illuminated from below (inside the wafer stage 7). It is configured. The illumination light transmitted through the slit pattern of the reference member 8 forms a projected image of the slit pattern on the back surface (pattern surface) of the reticle R via the projection optical system PL. The slit pattern formed on the reference member 8 is
Although not shown in FIG. 1, it is used when a reference position between the reticle R and the wafer W is set by a TTL type alignment sensor or a TTR type alignment sensor. When performing position measurement using the reference member 8, the position measurement device according to the present embodiment performs measurement using two sets of reference patterns among the reference marks formed on the reference member 8.

The wafer stage 7 is an XY stage for positioning the wafer W two-dimensionally in a plane perpendicular to the optical axis AX of the projection lens PL, and the wafer is arranged in a direction (Z direction) parallel to the optical axis AX of the projection lens PL. It is composed of a Z stage for positioning the W, a stage for slightly rotating the wafer W, a stage for adjusting the inclination of the wafer W with respect to the XY plane by changing the angle with respect to the Z axis, and the like. Wafer stage 7
An L-shaped movable mirror 9 is attached to one end of the upper surface of the mirror, and a laser interferometer 10 is arranged at a position facing the mirror surface of the movable mirror 9. Although shown in a simplified manner in FIG. 1, the movable mirror 9 includes a plane mirror having a reflecting surface perpendicular to the X axis and a plane mirror having a reflecting surface perpendicular to the Y axis. Also,
The laser interferometer 10 has two X-axis laser interferometers for irradiating the movable mirror 9 with a laser beam along the X-axis and a Y-axis laser for irradiating the movable mirror 9 with a laser beam along the Y-axis. The X coordinate and the Y coordinate of the wafer stage 7 are measured by one laser interferometer for the X axis and one laser interferometer for the Y axis. Also, 2 for X axis
The rotation angle of the wafer stage 7 in the XY plane is measured based on the difference between the measured values of the laser interferometers.

The two-dimensional coordinates of the wafer stage 7 are always detected by the laser interferometer 10 at a resolution of, for example, about 0.01 μm, and the coordinates of the wafer stage 7 are determined based on the coordinates in the X-axis direction and the Y-axis direction. (Static coordinate system) (X, Y) is determined. That is, the laser interferometer 10
Are the coordinate values on the stage coordinate system (X, Y). Laser interferometer 1
The position measurement signal PDS indicating the X coordinate, the Y coordinate, and the rotation angle measured by 0 is output to the main control system 12. The main control system 12 outputs a control signal for controlling the position of the wafer stage 7 to the motor 11 while monitoring the supplied position measurement signal PDS. The main control system 12 controls whether or not to emit the exposure light from a light source (not shown), the intensity of the exposure light when the exposure light is emitted, and controls the exposure light passing through the condenser lens 1 and the projection optical system PL. I do. The detailed description of the main control system 12 will be described later.

Further, the exposure apparatus of the present embodiment includes an off-axis type alignment optical system (hereinafter, referred to as an alignment sensor) on the side of the projection optical system PL. This alignment sensor forms a part of the position measuring device according to the embodiment of the present invention provided in the exposure apparatus according to the embodiment of the present invention, and is an FIA (Field Image Alignment).
ent) type alignment sensor. Hereinafter, this F
The IA type alignment sensor will be described. The alignment sensor includes an optical system (hereinafter, referred to as an FIA system) that measures position information of the alignment sensor AM to be measured in the XY plane. This F
The IA system is a position measurement optical system. Hereinafter, the FIA system will be described.

The FIA system includes a light source 13 for emitting illumination light IL1 for illuminating the wafer W, and an optical fiber 14 for guiding the illumination light IL1. As the light source 13, for example, a white light source such as a halogen lamp or a multi-brightness LED is used. Here, the reason that the halogen lamp 13 is used as the light source 13 of the illumination illumination light IL1 is that the wavelength range of the illumination light emitted from the halogen lamp is 500 to 800 nm,
This is because the wavelength range is such that the photoresist applied to the upper surface of the wafer W is not exposed, and the wavelength range is wide, so that the influence of the wavelength characteristic of the reflectance on the surface of the wafer W can be reduced.

The illumination light IL 1 emitted from the halogen lamp 13 passes through the optical fiber 14 and is emitted from the emission end of the optical fiber 14. The illumination light IL1 emitted from the optical fiber 14 passes through the condenser lens 15, the beam splitter 16, and the half mirror 17, and enters the objective lens 18. A prism (mirror) 19 fixed around the lower part of the barrel of the projection optical system PL so that the illumination light IL1 passing through the objective lens 18 does not block the projection field of view of the projection optical system PL.
Are reflected at substantially right angles to irradiate the wafer W. The objective lens 18 and the prism 19 form a part of an objective optical system. Although not shown in FIG. 1, an illumination field stop is arranged at a position conjugate with the surface of the wafer W in the optical path from the exit end of the optical fiber 14 to the objective lens 18. I have. The illumination field stop defines an area in which the alignment mark AM formed on the wafer W is irradiated with the illumination light IL1 from the light source 13.
The optical axis of the objective lens 18 is set on the wafer W so as to be perpendicular to the surface of the wafer W.

Illumination light IL1 reflected by wafer W
Again passes through the prism 19 and the objective lens 18 and
After being reflected by the lens 17, the index plate 2 is
Focus on 1 This index plate 21 is connected to the objective lens 18 and
Set to a conjugate relationship with the surface of wafer W by lens 20
Is done. Therefore, the alignment mark AM on the wafer W
Is formed on the index plate 21. FIG.
Lightment mark AM _XIs formed on the index plate 21
It is a figure showing a situation. On the index plate 21, it is long in the X-axis direction.
Index marks 21a and 21b in which the hand direction is set, and Y axis
Index marks 21c and 21d whose longitudinal directions are set in the directions
Are formed, and each of the index marks 21a to 21d is fine.
It is composed of three thin bar marks. Measurement view of FIA system
Accurate alignment mark AM in Nouchi_XIs placed
And the alignment mark AM as shown in FIG.
_XIs formed between the index marks 21a to 21d.
You. The illumination light IL1 that has passed through the index plate 21 is a relay lens.
22, the beam splitter 23, and the relay lens 24
The beam passes through the beam splitter 25. Beamspri
The light reflected by the shutter 25 is, for example, by a two-dimensional CCD or the like.
Alignment received by the imaging element 26
The images of the mark AM and the index mark are respectively on the image sensor 26.
Is imaged. Similarly, the beam splitter 25
The transmitted light is received by the image sensor 27.

The image pickup device 26 is electrically scanned along the imaged alignment marks AM _X and the index marks 21a, the image of 21b to the scanning line C1 of the video sampling region VS _X. FIG. 5B is a diagram illustrating an example of a waveform of an image signal obtained from the image sensor 26. In FIG. 5B,
The vertical axis represents the intensity of the image signal, and the horizontal axis represents the scanning position by the scanning line C1. As shown in FIG. 5B, the index marks 21c and 21d extending in the Y-axis direction are photographed as three black lines by the image sensor 26, so that the intensity of the image signal depends on the positions of the index marks 21c and 21d. It is extremely small.

[0030] On the other hand, six rectangles constituting the alignment mark AM _X, since only the edge is captured as a black line by the imaging device 26, the intensity of the image signal becomes minimum at a position corresponding to the position of the edge. Signal processing device 28
Is the index mark 21a on the basis of an image signal output from the image pickup device 26, (the center point of the index plate 21) the center position of 21b Xc and the center position Xm of the alignment mark AM _X
And the difference ΔX (= Xm−Xc) is obtained. Δ
X is when the center position Xm of the alignment mark AM _X is in the + X-axis direction from the center point Xc of the index plate 21 forward, -
When in the X-axis direction, a negative value is assumed. At this time, the main control system 12 inputs and stores the position measurement signal PDS of the wafer stage 7 obtained by the laser interferometer 10 and the positional deviation amount ΔX obtained from the signal processing device 28. Also,
With respect to the alignment mark AM _Y on the wafer W, the image sensor 27 and the signal processing device 2
8 detected.

The alignment sensor has a detection system (hereinafter, referred to as an "autofocus system") for detecting a height position of the surface of the wafer W in the Z-axis direction. When detecting the position information of the alignment mark AM in the XY plane, the alignment sensor measures the position information by arranging the wafer W at a height position where the surface of the wafer W is in a conjugate relationship with the imaging elements 26 and 27. Is preferable in consideration of measurement accuracy. Hereinafter, this height position is defined as a “focal position of the alignment sensor”. In the present embodiment, in order to realize high throughput, even if the wafer W is arranged at a position shifted from the focal position of the alignment sensor, the position information is measured without moving the wafer W in the Z-axis direction.

Since the FIA system constitutes a telecentric optical system, when the wafer W is arranged at a position shifted from the focus position of the alignment sensor, the image of the alignment mark AM is shifted laterally. ,
27 is formed. A similar phenomenon occurs when aberrations (for example, coma and astigmatism) remain in the FIA system. The amount of the lateral shift changes according to the amount of shift of the wafer W from the focal position of the alignment sensor. The autofocus system is provided for detecting how much the surface position of the wafer W is displaced in the Z-axis direction from the focal position of the alignment sensor. Hereinafter, this autofocus system will be described in detail. This autofocus system forms a focus detection optical system, and partially shares the optical path of the FIA system described above.

As shown in FIG. 1, the illumination light IL 2 emitted from the light source 30 passes through the optical fiber 31 and is emitted from the emission end of the optical fiber 31. The illumination light IL2 emitted from the light source 30 is light having a wavelength longer than the wavelength of the illumination light IL1 used in the FIA system. The illumination light IL2 emitted from the optical fiber 31 passes through a lens 32, a mirror 33, and a lens 34, and reaches a slit plate 35 having a slit-shaped opening. The light that has passed through the opening of the slit plate 35 is
After passing through the lens 36, it is reflected by the beam splitter 16 and combined with the illumination light IL1 from the light source 13. Then, the light passes through the half mirror 17, the lens 18, and the prism 19 in this order, and a slit image is projected on the wafer W.

The reflected light of the slit image from the wafer W sequentially passes through the lens 20, the index plate 21, and the lens 22, and is reflected by the beam splitter 23. The beam splitter 23 has a color filter that reflects or transmits light depending on a difference in wavelength. The color filter passes the illumination light IL1 used in the FIA system and reflects the illumination light IL2 used in the autofocus system. Beam splitter 23
The illumination light IL2 reflected by the detector 3
8 is photoelectrically detected. In the vicinity of the light receiving surface of the detector 38, a slit plate having a slit-shaped opening is provided in the same manner as the slit plate 35. Reach The detector 38 outputs a detection signal corresponding to the intensity of the received light to the signal processing device 39.

When the height position of the surface of the wafer W is detected by the autofocus system, the main control system 12
Causes the illumination light IL2 to be emitted from the light source 30 and causes the slit plate 35 to vibrate at a predetermined amplitude in the optical axis direction of the autofocus system as shown in FIG. The amplitude center at this time is a position conjugate with the light receiving surface of the detector 38. Then, the signal processing device 39 detects the signal from the detector 38 by the synchronous detection method, and the wafer W with respect to a predetermined height position (Z coordinate position) virtually set by the autofocus system.
And outputs a detection signal corresponding to the amount of deviation ΔZ in the Z-axis direction of the surface. Here, the predetermined height position defined by the autofocus system is set in advance to the focus position of the alignment sensor. Further, it is preferable that the focal position of the alignment sensor is set in advance so as to coincide with the image forming position of the projection optical system PL.

Although the configuration of the autofocus system provided in the alignment sensor has been described above, the position measuring apparatus and the exposure apparatus according to one embodiment of the present invention provide the wafer W with respect to the focal position of the alignment sensor output from the signal processing system 39. And a storage device 40 for storing a relationship between a detection signal indicating a shift amount ΔZ in the Z-axis direction and a position shift amount ΔX in the XY plane of the alignment mark AM obtained from the signal processing device 28. The storage device 40 is realized by a semiconductor storage device such as a random access memory (RAM) or a magnetic storage device such as a hard disk.

The configuration of the position measuring apparatus and the exposure apparatus according to the embodiment of the present invention has been described above. Next, the operation of the position measuring apparatus and the exposure apparatus according to the embodiment of the present invention, that is, the embodiment of the present invention will be described. The method of position measurement and the method of exposure will be described. In the position measuring method according to one embodiment of the present invention, the XY of the alignment mark AM formed on the wafer W by the alignment sensor is used.
Before measuring position information in the plane, a detection signal indicating a shift amount ΔZ of the wafer W in the Z-axis direction with respect to the focal position of the alignment sensor using an autofocus system and an FIA system provided in the alignment sensor in advance, and a signal processing device 28 XY of alignment mark AM obtained from
A process of obtaining the positional deviation amount ΔX in the plane and storing these relationships in the storage device 40 is performed. Hereinafter, this processing will be described.

FIG. 6 shows a displacement ΔZ of the wafer W with respect to the focal position of the alignment sensor in the Z-axis direction and a displacement ΔΔ of the alignment mark AM in the XY plane.
9 is a flowchart showing a flow for obtaining a relationship with X. In this process, the case where the position information of the alignment mark AM formed on the wafer W is measured will be described as an example. The measurement may be performed by using. The alignment mark AM formed on the wafer W depends on the surface condition of the wafer W and the alignment mark AM.
In some cases, the position in the XY plane is measured with a lateral shift depending on the shape (pattern) of the image. By performing measurement using the reference mark formed on the reference member 8, a relationship excluding the influence due to the shape of the alignment mark AM can be obtained. When the measurement is performed using the alignment mark AM formed on the wafer W, the above relationship can be obtained including the lateral shift amount generated based on the surface state of the wafer W and the shape (pattern) of the alignment mark AM.

When the operation is started, the main control system 12 moves the wafer stage 7 in the XY plane via the motor 11 to change the alignment mark AM to be measured among the alignment marks AM formed on the wafer W. It is arranged at the detection center of the alignment sensor (step S10). The position information of the alignment mark AM formed on the wafer W is stored in the main control system 12 in advance, and the wafer W is accurately arranged at a predetermined position on the wafer stage 7. Numeral 12 controls the position of the wafer stage 7 based on the XY coordinate values included in the position measurement signal PDS output from the laser interferometer 10 so that the alignment mark AM to be measured can be accurately positioned at the detection center point of the alignment sensor. Can be arranged.

When the alignment mark AM to be measured has been arranged at the detection center of the alignment sensor AM, the main control system 12 controls the motor 11 to move the wafer stage 7 to the Z position.
It is gradually moved in the axial direction (step S12). The moving range of the wafer stage 7 is within a predetermined range including the focus position of the alignment sensor. While the main control system 12 moves the wafer stage 7 within the movement range in the Z-axis direction,
The main control system 12 obtains a shift amount ΔZ in the Z direction from the focus position of the FIA system on the surface of the wafer W based on the detection signal obtained from the signal processing device 28 (step S).
14). Next, based on the measurement result obtained from the signal processing device 39, the amount of displacement ΔX in the X-axis direction between the detection center of the alignment sensor by the FIA system and the center of the alignment mark AM for which measurement is being performed (FIG. 5B) ΔX) is obtained (step S16). When the deviation amount ΔZ and the positional deviation amount ΔX are obtained, the main control system 12 stores them in the storage device 40 in association with each other (Step S).
18).

Next, it is determined whether the current position of the wafer W in the Z-axis direction is within a predetermined moving range and there is a remaining moving range (step S20). If it is determined that there is a remaining moving range, the process returns to step S12, and the above-described process is repeated. On the other hand, when it is determined that there is no remaining moving range in which the detection and measurement are performed and the detection and measurement are performed for the entire predetermined moving range, it is determined whether or not there is an alignment mark AM to be measured ( Step S22). When it is determined that there is a remaining alignment mark to be measured (the determination result is “YE
In the case of "S"), the process returns to step S10, and when it is determined that there is no other alignment mark to be measured (when the determination result is "NO"), a series of processes ends. In the above process, setting a plurality of measurement points along the Z-axis direction within a preset movement range and performing measurement at these measurement points reduces the time required for detection and measurement. It is preferable in aiming. Note that the relationship between the shift amount ΔZ and the position shift amount ΔX obtained at this time is discrete, but in this case, it is preferable to supplement the relationship with a quadratic curve or the like.

FIG. 7 is a diagram showing an example of the relationship between the shift amount ΔZ and the position shift amount ΔX obtained by performing the processing shown in FIG. The horizontal axis of the graph in FIG. 7 is the shift amount ΔZ of the surface of the wafer W with respect to the focus position of the alignment sensor, and the vertical axis is the shift amount ΔX of the alignment mark AM from the measurement center of the FIA system. The intersection of the vertical and horizontal axes is the point where ΔX = 0 and ΔZ = 0. The main control system 12 approximates the stored plurality of data as curves L1 to L5 shown in FIG. 7 and stores the data as detection error information of the measured alignment mark AM. Although curves L1 to L5 are shown in FIG. 7, a plurality of curves are not obtained from one alignment mark AM, but only one curve (for example, only the curve L2) is obtained.

FIG. 7 shows a plurality of curves, which are obtained by measuring a plurality of alignment marks AM having different shapes. FIG. 8 is a sectional view showing alignment marks AM having various shapes. Curves L1 to L5 in FIG. 7 are curves showing the relationship between the deviation amount ΔZ and the positional deviation amount ΔX obtained by measuring each of FIGS. 8 (a) to 8 (e). The alignment mark AM shown in FIGS. 8A to 8D has a rectangular cross-sectional shape, and the steps thereof are shown in FIGS. 8A, 8B, and 8.
The steps gradually become lower in the order of (c). FIG.
The alignment mark AM shown in FIG. 8D has a trapezoidal cross section, and the alignment mark AM shown in FIG. 8E has a semicircular cross section.

As shown in FIG. 7, depending on the shape of the alignment mark AM formed on the wafer W, the shift amount Δ
The relationship between Z and the displacement ΔX is different. In FIG. 7, when the value of the displacement amount ΔZ is 0, the value of the displacement amount ΔX should always be 0 because the alignment mark AM is located at the focal position of the alignment sensor. However, actually, due to the aberration of the FIA system, the state of the inclination (telecentric inclination) of the optical axis of the FIA system with respect to the optical axis AX of the projection optical system PL, etc.
Even if the position information is measured while the alignment mark AM is arranged at the focal position of the alignment sensor,
This is the source of the error (X ₁ , X ₂ , X ₄ , X ₅ ) in the measurement result. Note that in the diagram shown in FIG. 7, when the relationship between the displacement amount ΔZ and the positional displacement amount ΔX is a straight line, F
This is due to the telecentric tilt of the IA system. Also, the deviation amount ΔZ
When the relationship between the displacement and the displacement ΔX is a curve, it is due to the telecentric inclination and the aberration.

The flow shown in FIG. 6 is a flow chart for obtaining the relationship between the plurality of alignment marks AM formed on one wafer W and the positional deviation amount ΔX in the XY plane. When the relationship is determined for the wafer W, the wafer W placed on the wafer holder 6 is replaced and the processing shown in FIG. Normally, in the manufacture of a semiconductor device or the like, processing is performed in lot units using a plurality of wafers W as units. In this case, the detection and measurement are performed on at least the first substrate of the lot, and the detection and measurement are not performed on the other wafers W in the lot, in order to shorten the time required for measurement. Is preferred.

In the above processing, the shift amount ΔZ and the position shift amount ΔX
Is obtained, and the relationship is stored in the storage device 40. Next, the alignment mark AM formed on the wafer W using the relationship stored in the storage device 40
The operation at the time of measuring the position information will be described. FIG.
9 is a flowchart showing a flow when measuring the position information of the alignment mark AM formed on the wafer W. When the processing starts, the main control system 12 outputs a control signal to a wafer loader (not shown), and places the wafer W on the wafer holder 6 on the wafer stage 7 (Step S30). When the wafer W is mounted on the wafer holder 6, the main control system 12 controls the motor 11 to move the wafer stage 7 in the XY plane to measure the alignment mark AM on the wafer W for measurement by the alignment sensor. (Step S32).

When the alignment mark AM to be measured is placed within the measurement field of view of the alignment sensor, the autofocus system provided in the alignment sensor next provides
A deviation amount ΔZ of the surface of the wafer W in the Z-axis direction from the focal position of the alignment sensor is detected (step S3).
4). This detection result is output to the main control system 12. Next, the main control system 12 reads the relationship between the displacement amount ΔZ and the position displacement amount ΔX stored in the storage device 40 with respect to the alignment mark AM for which measurement is being performed. Then, a position shift amount ΔX corresponding to the calculated ΔZ is calculated.

Next, the main control system 12 controls the alignment mark by the FIA system while maintaining the relationship between the focus position of the alignment sensor and the surface position of the wafer W when the detection is performed using the autofocus system. Control is performed so as to measure the position information (step S38). That is,
The main control system 12 controls the wafer W when the shift amount ΔZ is detected.
Is maintained without moving the wafer stage 7, and the position information of the alignment sensor AM is measured in this state. Therefore, since the wafer W is not located at the focal position of the alignment sensor, the measurement result includes the positional deviation amount ΔX caused by the deviation amount Z. And
Next, the main control system 12 corrects the positional information of the alignment mark AM obtained by measurement (including the positional deviation amount ΔX caused by the deviation amount Z) with the positional deviation amount ΔX calculated in step S36. By doing so, the positional deviation amount ΔX excluding the influence of the positional deviation amount ΔX caused by the deviation amount Z is obtained (step S40). Through the above processing, the position information of the alignment mark AM for which measurement is being performed can be obtained.

Next, it is determined whether or not there is an alignment mark AM to be subjected to capture measurement (step S4).
2). When it is determined that there is a remaining alignment mark to be measured (when the determination result is “YES”), the process returns to step S30, and when it is determined that there is no other alignment mark to be measured (determination The result is "N
In the case of "O"), a series of processing ends. Note that the flow shown in FIG. 9 is a diagram showing a flow when measuring the position information of the plurality of alignment marks AM formed on one wafer W, and obtains the relationship with respect to the plurality of wafers W. In this case, the processing shown in FIG. 9 is repeated.

By performing the above processing, the position information of the alignment mark AM formed on the wafer W is measured.
When performing exposure of a shot area set on the wafer W based on the measurement result, first, the main control system 12
The wafer stage 7 is moved in the XY plane based on the detection result of the system. The main control system 12 stores in advance the distance between the measurement center of the FIA system and the projection position of the center point of the reticle R by the projection optical system PL as the baseline amount BL. Using this baseline amount BL, the main control system 12 moves the wafer stage 7 in the X-axis direction by BL + ΔX. Also, by moving the position in the Y-axis direction according to the movement amount measured in the same manner as described above, the shot area to be exposed can be accurately superimposed on the projected image of the pattern of the reticle R. Then, the exposure light EL is irradiated onto the reticle R, and the image of the pattern formed in the pattern area PA of the reticle R is transferred into the exposure target shot area set on the wafer W.

By the processing described above, the time required for measuring the position information can be reduced without lowering the measurement accuracy, and as a result, the throughput of the exposure processing can be improved. Further, the shift amount ΔZ and the position shift amount ΔX for each of the plurality of different types of alignment marks AM.
Is stored in the storage device 40 in advance, it is possible to flexibly cope with a wafer W whose surface state changes through various processes.

As described above, the position measuring apparatus and method, and the exposure apparatus and the exposure method according to one embodiment of the present invention have been described. It is. For example, in FIG. 9, the relationship between the shift amount ΔZ and the positional shift amount ΔX for each alignment mark formed on one wafer W is stored in the storage device 4.
Although the case where it is stored as 0 has been described as an example, the average of the relationship between the deviation amount ΔZ and the positional deviation amount ΔX obtained by measuring the alignment marks AM formed on the plurality of wafers W is described. The value may be a relationship between the shift amount ΔZ and the position shift amount ΔX with respect to the alignment mark AM. In this way, by using the average value, while improving the reliability,
The time required for measuring the position information can be reduced without lowering the measurement accuracy. In addition, alignment mark A
The average value of the relationship between the shift amount ΔZ and the position shift amount ΔX for each M may be defined as the relationship between the shift amount ΔZ and the position shift amount ΔX for all the alignment marks AM formed on one wafer W.

In the above-described embodiment, the FI
Since both the telecentric tilt of the A system and the aberration of the FIA system often occur, the relationship between the shift amount ΔZ and the position shift amount ΔX is determined by the flow shown in FIG. Are obtained by actually measuring both. However, when the influence of aberration can be ignored, if the amount of telecentric inclination θ of the alignment sensor is measured in advance and the position of the surface of the wafer W from the focus position of the alignment sensor is detected by the autofocus system, Since the displacement amount ΔX can be obtained from the following equation (1), the relationship between the displacement amount ΔZ and the displacement amount ΔX can be obtained without measuring the displacement amount ΔX. ΔX = ΔZ · θ (1)

Therefore, in step S34 of the flow shown in FIG. 9 for measuring the position information of the alignment mark AM, after measuring the deviation amount ΔZ, if the measurement result obtained in step S36 is X (ΔZ), The displacement X (0) expected to be obtained when the wafer W is placed at the focal position of the alignment sensor can be obtained by the following equation (2). X (0) = X (ΔZ) −ΔX = X (ΔZ) −ΔZ · θ (2) Therefore, when the influence of the aberration can be ignored and only the displacement amount due to the telecentric tilt is considered, The displacement amount X (0) obtained by the above equation (2) is calculated using the alignment mark A
It may be used as the position information of M.

After the position information of each alignment mark AM is obtained by performing the processing of step S40 in FIG. 9, the so-called enhanced global alignment for obtaining the arrangement of each shot area on the stationary coordinate system (so-called enhanced global alignment) is performed. EGA) may be performed. Since this EGA is disclosed in detail in Japanese Patent Application Laid-Open No. 61-44429, a detailed description is omitted here. When the EGA is used, the arrangement of the shot areas on the wafer W is obtained, and the main control system 12 moves the wafer stage 7 in a stepping manner based on the obtained arrangement coordinates, and moves each shot area to the pattern of the reticle R. Exposure can be performed so as to be accurately superimposed on the projected image.

The present invention is not limited to the alignment system as in the above-described embodiment. For example, by irradiating a light beam onto the wafer W and scanning the alignment mark AM on the wafer W with respect to the light beam, A similar effect can be obtained by using the light beam scanning type alignment system (laser step alignment) or the like which detects the diffracted light and detects the coordinate position of the alignment mark.

The exposure apparatus (FIG. 1) according to the above-described embodiment of the present invention can precisely control the position of the wafer W at high speed, and can perform exposure with high exposure accuracy while improving throughput. As described above, a reticle alignment system including the motor 2, the reticle stage 3, and the movable mirror 5,
Each element shown in FIG. 1 such as a wafer alignment system including a wafer holder 6, a wafer stage 7, a reference member 8, a moving mirror 9, and a laser interferometer 10, and a projection optical system PL is electrically, mechanically, or optically. After being connected and assembled,
It is manufactured by comprehensive adjustment (electrical adjustment, operation confirmation, etc.). It is desirable that the manufacture of the exposure apparatus be performed in a clean room in which the temperature, cleanliness, and the like are controlled.

Next, the manufacture of a device using the exposure apparatus and the exposure method according to one embodiment of the present invention will be described.
FIG. 10 is a flowchart of production of devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.) using the exposure apparatus according to one embodiment of the present invention. As shown in FIG.
First, in step S50 (design step), device function design (for example, circuit design of a semiconductor device) is performed, and pattern design for realizing the function is performed. Subsequently, in step S51 (mask manufacturing step), a mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step S52 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

Next, in step S53 (wafer process step), actual circuits and the like are formed on the wafer by lithography using the mask and the wafer prepared in steps S50 to S52. Then
In step S54 (assembly step), step S
Chips are formed using the wafer processed in 53.
Step S54 includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). Finally, in step S55 (inspection step), inspections such as an operation confirmation test and a durability test of the device manufactured in step S55 are performed. After these steps, the device is completed and shipped.

The exposure apparatus of the present embodiment can be applied to a scanning exposure apparatus (US Pat. No. 5,473,410) for exposing a pattern of a mask by synchronously moving a mask and a substrate. Further, the exposure apparatus of the present embodiment can be applied to a proximity exposure apparatus that exposes a mask pattern by bringing a mask and a substrate into close contact without using a projection optical system. Further, the application of the exposure apparatus is not limited to an exposure apparatus for manufacturing semiconductors. Widely applicable to the exposure apparatus.

The light source of the exposure apparatus of this embodiment is a g-line (4
36 nm), i-line (365 nm), KrF excimer laser (248 nm), ArF excimer laser (193n)
m), not only the F ₂ laser (157 nm) only, it is possible to use a charged particle beam such as X-ray or electron beam. For example,
When an electron beam is used, thermionic emission type lanthanum hexaborite (LaB ₆ ), tantalum (T
a) can be used.

The magnification of the projection optical system may be not only a reduction system but also any one of a unity magnification and an enlargement system. As the projection optical system,
When far ultraviolet rays such as an excimer laser are used, a material that transmits far ultraviolet rays such as quartz or fluorite is used as a glass material, and F
_{(2) When a} laser or X-ray is used, a catadioptric or refractive optical system is used (a reticle is also of a reflection type). When an electron beam is used, the optical system includes an electron lens and a deflector. An electron optical system may be used. It goes without saying that the optical path through which the electron beam passes is in a vacuum state.

When a linear motor (see US Pat. No. 5,623,853 or US Pat. No. 5,528,118) is used for a wafer stage or a reticle stage, either an air levitation type using an air bearing or a magnetic levitation type using Lorentz force or reactance force is used. May be used. The stage may be of a type that moves along a guide or a guideless type that does not have a guide. As the stage driving device, a planar motor that drives a stage by electromagnetic force with a magnet unit having two-dimensionally arranged magnets facing an armature unit having two-dimensionally arranged coils may be used. In this case, one of the magnet unit and the armature unit may be connected to the stage, and the other of the magnet unit and the armature unit may be provided on the moving surface side of the stage.

The reaction force generated by the movement of the wafer stage is disclosed in JP-A-8-166475 (US Pat. Nos. 5,528,118).
As described in (1), the material may be mechanically released to the floor (ground) using a frame member. The reaction force generated by the movement of the reticle stage is mechanically released to the floor (ground) using a frame member as described in Japanese Patent Application Laid-Open No. 8-330224 (US S / N 08 / 416,558). Is also good.

[0065]

As described above, according to the position measuring apparatus according to the first aspect of the present invention, the change in the state of alignment between the focus position of the focus detection optical system and the object and the change in response to this change The relationship between the change in the position information of the mark and the change in the two-dimensional plane is stored in advance in the storage means, and when the position information of the mark is measured, the focus position of the detected focus detection optical system and the object are compared. The position information of the mark in the two-dimensional plane is obtained by correcting the position information measured by the position measurement unit based on the change in the matching state and the relationship stored in the storage unit. Therefore, even if the object is shifted from the in-focus position of the focus detection optical system, or the position measurement optical system is left with aberrations such as coma and astigmatism, and the position information is measured in a state where the mark is laterally shifted, Since the position information in which the lateral displacement has been corrected can be obtained, there is an effect that the position information of the mark in the two-dimensional plane can be measured without lowering the measurement accuracy. According to the position measuring device of the second aspect of the present invention, the storage device corresponds to the change in the vertical position of the object and the change in the position information in a predetermined range of the vertical method including the focus position of the focus detection optical system. Even if the absolute value of the shift amount in the Z-axis direction and the shift amount in the −Z-axis direction with respect to the focus position of the focus detection optical system are equal, the shift amount of the position information in the two-dimensional plane is stored. Even when the absolute values are different (this phenomenon is a phenomenon mainly caused by aberration), there is an effect that the position information can be measured without lowering the accuracy of the position information. Further, according to the position measuring device of the third aspect of the present invention,
Since the change of the measurement value of the position measurement means is stored in the storage means while moving the stage on which the object is mounted in the vertical direction, the vertical position of the object with respect to the focus position of the focus detection optical system in a short time. The effect is that the relationship between the change and the change in the position information of the mark in the two-dimensional plane can be continuously obtained. Further, according to the position measuring device of the fourth aspect of the present invention, when the detection unit detects, the reference mark provided on the stage is measured to change the vertical position of the object with respect to the focus position of the focus detection optical system. And the relationship between the change in the position information of the mark in the two-dimensional plane, and the deviation from the focus position of the focus detection optical system and the aberration remaining in the position measurement optical system in the two-dimensional plane. There is an effect that the lateral shift amount can be obtained without being affected by the shape of the mark formed on the object. Further, according to the position measuring device of the fifth aspect of the present invention, upon detection by the detecting means, the mark formed on the object is measured, and the change in the vertical position of the object with respect to the focus position of the focus detection optical system is determined. Since the relationship with the change in the position information of the mark in the two-dimensional plane is determined, the lateral deviation in the two-dimensional plane due to the deviation from the focus position of the focus detection optical system and the aberration remaining in the position measurement optical system The amount can be obtained including the amount of lateral shift generated according to the shape of the mark formed on the object. Therefore, when the shape of the mark formed on the object is a shape that is likely to cause a lateral displacement in the measurement of the position information, the lateral displacement can be obtained including the influence due to the shape of the mark. Is very suitable for obtaining mark position information. According to the position measuring apparatus of the sixth aspect of the present invention, the change in the vertical position of the object with respect to the focus position of the focus detection optical system for a plurality of substrates in lots and the change in the two-dimensional plane When determining the relationship with the change in the position information of the mark, detection is performed on the first substrate of the lot or several substrates at the beginning of the lot, and for the remaining substrates in the lot, The position information of the mark measured based on the detection result is corrected. Therefore, the processing for obtaining the relationship between the change in the vertical position of the object with respect to the focus position of the focus detection optical system and the change in the position information of the mark in the two-dimensional plane is not performed on these remaining substrates. There is an effect that the time required for measurement of the measurement can be reduced. Further, according to the position measuring apparatus of the seventh aspect of the present invention, when detecting the first substrate of the lot or the several substrates at the beginning of the lot, the measurement value accompanying the vertical movement of the stage is detected. The change is obtained for each of the plurality of marks, and the average value is stored in the storage unit. For the remaining substrates in the lot, the position information of the mark measured based on the average value stored in the storage unit is corrected. I have to. Substrates that have been subjected to substantially the same processing are provided in the same lot, the surface condition of each substrate is substantially the same, and the situation in which the lateral shift amount of each mark is completely different even within the substrate does not often occur. However, if the correction is performed based only on the measurement result obtained from one substrate, high reliability may not be obtained, for example, when the surface state of the substrate that is accidentally measured is poor. Thus, obtaining the average value for each mark has the effect of improving reliability and reducing the time required for position information measurement without lowering measurement accuracy. Further, according to the position measuring device of the eighth aspect of the present invention, even if the object is arranged vertically displaced from the focus position of the focus detection optical system, the stage is not moved. The control means controls the stage and the position measurement means so as to perform the measurement operation in a state where the object is shifted from the in-focus position. Therefore, since the control for arranging the object at the focal position of the focus detection optical system for each mark is omitted, the time required for measuring the position information can be extremely reduced, and as a result, the throughput can be improved. effective. Further, according to the position measuring device of the ninth aspect of the present invention, the change in the state of alignment between the focus position of the focus detection optical system and the object, the position information of the mark in the two-dimensional plane according to this change, Is stored in the storage means in advance, and even when the object is not located at the in-focus position of the focus detection optical system, position information in the two-dimensional plane of the mark is measured by the position measurement means. Then, the position information is corrected based on the relationship stored in the storage means. Therefore, since the control for arranging the object at the focal position of the focus detection optical system for each mark is omitted, the time required for measuring the position information can be extremely reduced, and the position of the mark can be reduced without lowering the measurement accuracy. There is an effect that information can be measured.
Further, according to the exposure apparatus of the present invention, the measurement result of the position information is obtained in a short time without lowering the measurement accuracy by the position measurement device, and the position of the substrate is adjusted based on the measurement result. Since the predetermined pattern is transferred on top,
There is an effect that the alignment can be performed with high accuracy and the throughput can be improved. Further, according to the position measuring method invention according to the first and second aspects of the present invention, a change in the state of alignment between the focus position of the focus detection optical system and the object, and a change in the two-dimensional plane corresponding to the change. Is stored in advance in the storage means, and when measuring the position information of the mark,
By correcting the position information measured by the position measuring means based on the detected change of the in-focus position of the focus detection optical system and the state of alignment with the object and the relationship stored in the storage means, a two-dimensional plane is obtained. Is required for the position information of the mark. Therefore, even if the object is shifted from the in-focus position of the focus detection optical system, or the position measurement optical system is left with aberrations such as coma and astigmatism, and the position information is measured in a state where the mark is laterally shifted, Since the position information in which the lateral displacement has been corrected can be obtained, there is an effect that the position information of the mark in the two-dimensional plane can be measured without lowering the measurement accuracy. Further, according to the position measuring method according to the third aspect of the present invention, the reference mark provided on the stage or the mark formed in the shape of an object is measured, and the vertical position of the object with respect to the focus position of the focus detection optical system is measured. Of the mark and the change in the position information of the mark in the two-dimensional plane. Therefore, the amount of lateral displacement in a two-dimensional plane caused by the deviation of the focus detection optical system from the in-focus position and the aberration remaining in the position measurement optical system is affected by the shape of the mark formed on the object. However, when the position information has a shape that is likely to cause a lateral shift in the measurement of the position information, there is an effect that a relationship including an influence due to the shape of the mark can be obtained. Further, according to the position measurement methods according to the fourth and fifth aspects of the present invention, the change in the state of alignment between the focus position of the focus detection optical system and the object, and the change in the two-dimensional plane corresponding to this change. The relationship between the position of the mark and the change is stored in advance, and even when the object is not located at the in-focus position of the focus detection optical system, the position information in the two-dimensional plane is obtained by the position measuring means. Is measured, and the position information is corrected based on the relationship stored in the storage means. Therefore, since the control for arranging the object at the focal position of the focus detection optical system for each mark is omitted, the time required for measuring the position information can be extremely reduced, and the position of the mark can be reduced without lowering the measurement accuracy. There is an effect that information can be measured. Further, according to the exposure method of the present invention, the measurement result of the position information is obtained in a short time without lowering the measurement accuracy, and the predetermined pattern is formed on the substrate by performing the alignment of the substrate based on the measurement result. Since the image is transferred, there is an effect that the alignment can be performed with high accuracy and the throughput can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an exposure apparatus according to an embodiment of the present invention including a position measuring device according to an embodiment of the present invention.

FIG. 2 is a top view showing a schematic configuration example of a wafer W.

FIG. 3 is a top view showing a configuration in the vicinity of one shot area.

FIG. 4 is a top view illustrating a configuration of an example of an alignment mark AM for two-dimensional measurement.

[Figure 5] alignment mark AM _X of the image is the index plate 21
6A and 6B are diagrams illustrating a state in which an image is formed on an upper side and a diagram illustrating an example of a waveform of an image signal obtained from the imaging element 26. FIG.

FIG. 6 is a flowchart showing a flow for obtaining a relationship between a shift amount ΔZ of a wafer W in a Z-axis direction with respect to a focal position of an alignment sensor and a position shift amount ΔX of an alignment mark AM in an XY plane.

7 is a shift amount Δ obtained by performing the processing shown in FIG.
FIG. 6 is a diagram illustrating an example of a relationship between Z and a positional deviation amount ΔX.

FIG. 8 is a sectional view showing alignment marks AM having various shapes.

FIG. 9 is a flowchart showing a flow when measuring position information of an alignment mark AM formed on a wafer W.

FIG. 10 is a flowchart showing a procedure for manufacturing a device using the exposure apparatus according to the embodiment of the present invention.

[Explanation of symbols]

7 Wafer stage (stage) 8 Reference member (reference mark) 11 Motor (positioning means) 12 Main control system (detection means, positioning means, control means) 13 Light source (position measurement optical system) 14 Optical fiber (position measurement optical system) 15 Condenser lens (position measurement optical system) 16 Beam splitter (position measurement optical system, focus detection optical system) 17 Half mirror (position measurement optical system, focus detection optical system) 18 Objective lens (objective optical system, position measurement optical system, Focus detecting optical system) 19 Prism (objective optical system, position measuring optical system, focus detecting optical system) 20 Lens (position measuring optical system, focus detecting optical system) 21 Index plate (position measuring optical system, focus detecting optical system) 22 Lens (position measurement optical system, focus detection optical system) 23 Beam splitter (position measurement optical system, focus detection optical system) 24 relay lens (Position measurement optical system) 25 Beam splitter (position measurement optical system) 26 Image sensor (position measurement optical system) 27 Image sensor (position measurement optical system) 28 Signal processing device (position measurement means) 30 Light source (focus detection optical system) Reference Signs List 31 optical fiber (focus detection optical system) 32 lens (focus detection optical system) 33 mirror (focus detection optical system) 34 lens (focus detection optical system) 35 slit plate (focus detection optical system) 36 lens (focus detection optical system) 37 lens (focus detection optical system) 38 detectors (focus detection optical system) 39 signal processing system (focus detector) 40 memory (storage means) AM, AM _X, AM _Y alignment mark (mark) PA pattern region (predetermined Pattern, device pattern) W Wafer (object, substrate)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/30 525B 526A F-term (Reference) 2F065 AA03 AA06 AA07 AA24 BB27 CC18 CC19 DD06 EE00 FF01 FF04 FF10 FF55 FF61 GG02 GG07 GG24 JJ03 JJ05 JJ26 LL02 LL04 LL12 LL20 LL22 LL30 LL42 LL46 LL59 MM03 PP02 PP12 PP22 PP24 QQ23 QQ28 QQ34 TT02 UU06 UU07 2H051 AA10 BA72 CB11 CC03 CC04 GB12 JA05 JA03 JA05 JA03 JA02 JA05 LA03 LA04 LA08 MA27 5F046 DA14 DB05 DB10 ED02 FC04 FC06

Claims (17)

[Claims] 1. A position measuring means for measuring position information of a mark formed on an object in a two-dimensional plane via a position measuring optical system including an objective optical system, the objective optical system and the position measuring optical. Including part of the system,
A focus detection unit that has a focus detection optical system having a focus position in a direction perpendicular to the two-dimensional plane, and detects a state of alignment between the focus position and the object via the focus detection optical system; And storage means for storing a relationship between a change in the matching state and a change in the position information, based on the relationship stored in the storage means and a measurement value measured by the position measurement means. A position measuring device for obtaining position information of the mark in the two-dimensional plane. 2. The storage means stores the position information when the object is present at each of a plurality of vertical positions within the predetermined vertical direction range including the in-focus position, based on the change in the vertical position and the change in the vertical position. 2. The position measuring device according to claim 1, wherein a change in the position information is stored in association with the change. 3. A stage movable in the vertical direction with the object placed thereon, and a detector for detecting a change in a value measured by the position measuring unit accompanying the vertical movement of the stage. The position measuring device according to claim 1, wherein the storage unit stores a detection result obtained by the detection unit. 4. The position measuring apparatus according to claim 3, wherein said position measuring means measures position information of a reference mark provided on said stage when detecting by said detecting means. 5. The apparatus according to claim 3, wherein said position measuring means measures position information of a mark formed on said object placed on said stage when detecting by said detecting means. Position measuring device. 6. The object is a substrate in which a plurality of substrates subjected to a predetermined process are set as a set of lot units, and the detection means performs the detection on at least a first substrate of the lot. The position measuring device according to claim 5, wherein: 7. A plurality of said marks are formed on said substrate, and said detecting means changes said measured value associated with said vertical movement of said stage, obtained for each of said plurality of marks. 7. The position measuring apparatus according to claim 6, wherein the storage unit stores an average value of a change in the measured value for each mark in association with the movement in the vertical direction. 8. A position measuring device for measuring position information of a mark formed on an object in a two-dimensional plane, comprising: a focus detection optical system having a focus position in a direction perpendicular to the two-dimensional plane. Focus detection means for detecting a state of alignment between the in-focus position and the object; position measurement means for measuring position information of the mark in the two-dimensional plane; and A stage that moves in a two-dimensional plane and in the vertical direction; and a measuring operation by the position measurement unit without moving the stage in the vertical direction based on the alignment state detected by the focus detection unit. Control means for controlling the stage and the position measurement means so as to perform the position measurement. 9. A storage unit for storing a relationship between a change in the matching state and a change in the position information, wherein the relationship stored in the storage unit and a measurement value measured by the position measurement unit 9. The position measuring device according to claim 8, wherein position information of the mark in the two-dimensional plane is obtained based on the following. 10. A positioning means for positioning a substrate on which the mark is formed, based on the position information of the mark obtained by the position measuring device according to claim 1. An exposure apparatus, comprising: transferring a predetermined pattern onto the substrate positioned by the positioning unit. 11. A position measuring method for measuring position information of a mark formed on an object in a two-dimensional plane, wherein the position information of the mark in the two-dimensional plane is measured using an objective optical system. Measuring via an optical system, including the objective optical system and a part of the position measuring optical system,
Through a focus detection optical system having a focus position in a direction perpendicular to the two-dimensional plane, a matching state between the focus position and the object is detected, and a change in the matching state and a change in the position information And determining position information of the mark in the two-dimensional plane based on the stored relationship and the measured value. 12. Before the determination of the position information, a change in the measurement value accompanying a change in the alignment state due to the movement of the object in the vertical direction is detected. The position measurement method according to claim 11, wherein the relation obtained based on a result is stored. 13. The relationship may be a position information of a reference mark fixed on a stage on which the object is mounted, or a position information of a mark formed on the object mounted on the stage. 13. The position measurement method according to claim 12, wherein the position measurement method is obtained by detecting a change in a measurement value accompanying the vertical movement of the stage. 14. A position measuring method for measuring position information of a mark formed on an object in a two-dimensional plane, the focus detection optical system having a focus position in a direction perpendicular to the two-dimensional plane. Detecting the state of alignment between the in-focus position and the object, and without moving the stage on which the object is placed in the vertical direction based on the result of detection of the alignment state, A position measurement method, wherein the position information is measured in the two-dimensional plane. 15. The position measurement method according to claim 14, wherein the measurement of the position information is performed after the detection of the matching state. 16. A substrate on which the mark is formed is positioned based on the position information of the mark obtained by the position measurement method according to claim 11. An exposure method, wherein a predetermined pattern is transferred onto the positioned substrate. 17. An exposure method according to claim 16,
A device manufacturing method, comprising a step of transferring a device pattern onto the substrate.