JP2001267196A - Position detecting apparatus, position detecting method, aligner and exposing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect with a high accuracy the position of marks to be tested on an object to be tested. SOLUTION: A main control system 13 stores the results of detection of an image pickup element 41 when only illuminating light IL2 is emitted as a first correction value, and stores the results of detection of an image pickup element 44 when only illuminating light IL1 is emitted as a second correction value. The main control system 13 also calculates the amount of change of the relative position between the image pickup elements 41 and 44 from the results of detection of the image pickup elements 41 and 44 when the illuminating light IL1 or the illumination light IL2 is emitted. The results of detection of the image pickup element 41 when both of the illumination light IL1 and IL2 is emitted are corrected by the first correction value and the position information of an alignment mark AM is calculated, the results of detection of the image pickup element 44 are corrected by the second correction value and the position information of an index mark 34 is calculated and the position information is corrected by the amount of change.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device and a position detecting method for detecting position information of a test mark formed on a test object such as a substrate or a reticle in a process of manufacturing a semiconductor device or a liquid crystal display device. Exposure apparatus for aligning (aligning) a substrate and a reticle based on positional information of a test mark detected using the apparatus and the method, and exposing and transferring a pattern formed on the reticle onto the substrate And 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. Projection exposure on a semiconductor wafer, a glass plate or the like coated with a photosensitive agent is repeatedly performed. As the projection exposure, for example, a step-and-repeat type exposure apparatus is used. When performing projection exposure, it is necessary to precisely match the position of the substrate with the position of the pattern image formed on the reticle to be projected. In recent years, particularly in the manufacture of semiconductor devices, patterns to be formed have become finer, and there has been a demand for improved alignment accuracy in order to manufacture semiconductor devices having desired performance. A test mark for detecting the position of the reticle or the substrate is formed on the substrate or reticle, and the exposure apparatus detects a position of the reticle or the substrate by detecting the position information of the test mark. Have.

A reticle position detecting device for detecting reticle position information generally uses an exposure light for exposing a substrate as a light source. The detection method of the reticle position detection device includes, for example, a VRA (Visual Reticle Ali
gnment) method. In the VRA system, an optical image obtained by irradiating exposure light on a test mark formed on a reticle before a substrate is transferred onto a stage is converted to a CCD (Charge C).
The image signal is converted into an image signal by an imaging device such as an Oupled Device, and image processing of the image signal is performed to detect positional information of the test mark.

A substrate position detecting device for detecting positional information of a substrate changes the surface state (roughness) of a substrate to be measured in a process of manufacturing a semiconductor element, a liquid crystal display element, or the like. It is difficult to accurately detect the position information of the substrate by the device, and different devices are generally used according to the surface condition of the substrate. The main components of these devices are LSA (Laser Step Alignment).
t) method, FIA (Field Image Alignment) method, LI
A (Laser Interferometric Alignment) type is available.

An LSA type substrate position detecting device irradiates a test mark formed on a substrate with a laser beam, and measures position information of the test mark by using diffracted / scattered light. This device has been widely used for semiconductor wafers in various manufacturing processes. The FIA type substrate position detecting device illuminates a test mark using a light source having a wide wavelength band such as a halogen lamp, converts an image of the test mark obtained as a result into an image signal, and performs image processing. This is a substrate position detection device that performs position measurement by using an asymmetric test mark formed on an aluminum layer or a substrate surface. The LIA type substrate position detecting device irradiates laser beams having slightly different wavelengths from two directions to a diffraction grating-like test mark formed on the substrate surface, and causes the resulting two diffracted lights to interfere with each other. This is a substrate position detection device that detects position information of a test mark from the phase of interference light.
This LIA type substrate position detecting device is effective when used for a test mark having a low step or a substrate having a large surface roughness.

[0006] The position detecting device includes a TTL (through-the-lens) system for detecting position information of a test mark on a substrate via a projection optical system. Off-axis method for detecting the position information of the above-described test mark, and TTR (through the reticle) method for simultaneously observing the substrate and the reticle via the projection optical system and detecting the relative positional relationship between them There is.
When aligning the reticle with the substrate using these position detecting devices, the baseline amount, which is the distance between the measurement center of the position detecting device and the center of the projected image of the reticle pattern (exposure center), is determined in advance. It has been demanded. Then, the position detecting device detects the amount of deviation of the mark to be measured from the measurement center, and moves the substrate by a distance obtained by correcting the amount of deviation by the baseline amount, thereby defining a partitioned area (shot area) set on the substrate. After the center of the shot is accurately aligned with the center of exposure, the shot area is exposed by exposure light. In the process of using and maintaining the exposure apparatus, the baseline amount may fluctuate gradually.
Alignment accuracy (overlay accuracy) decreases. Therefore, for example, it is necessary to periodically perform a baseline check for accurately measuring the distance between the measurement center of the position detection device and the exposure center.

Next, an example of the overall operation of the exposure apparatus will be outlined as follows.

First, before the substrate is conveyed to the exposure position, the reticle position detecting device detects the position information of the test mark formed on the reticle, and adjusts the position of the reticle based on this position information. Next, the substrate is transported to the exposure position, and the position information of the test mark formed on the substrate is detected by the substrate position detecting device. Then, based on the positional information of the test mark formed on the substrate, the substrate is moved by a distance corrected in the plane perpendicular to the optical axis of the exposure light by the amount of deviation indicated by the positional information of the substrate by the baseline amount. Then, after aligning the relative position between the shot area formed on the substrate and the reticle, the reticle is irradiated with exposure light to expose and transfer the image of the pattern formed on the reticle onto the substrate.

Next, the above-mentioned FIA type substrate position detecting device will be described in more detail. An FIA type substrate position detecting device illuminates a test mark formed on a substrate using a light source having a wide wavelength band such as a halogen lamp, and an optical image of the test mark obtained as a result is captured by a CCD or the like. The position information of the test mark is detected by converting the image signal into an image signal by an element and performing image processing on the image signal. However, when performing the image processing, the displacement of the test mark with respect to the measurement center of the substrate position detecting device is performed. The position information of the test mark must be detected by calculating the amount. In order to detect the amount of deviation from the center of measurement, the substrate position detection device is provided with an index plate indicating the reference of the detection range in the optical system, and the image obtained by irradiating the index plate and the image of the test mark are combined. Image processing of the obtained optical image is performed to calculate a shift amount of the test mark from the measurement center.

In recent years, in a substrate position detecting apparatus of the FIA system, a target mark and an index plate are respectively illuminated by using a first light source and a second light source having different wavelength bands, and image information detected by different photodetectors respectively. A technology that stabilizes the detection accuracy by detecting drift (displacement) of the measurement center position of the substrate position detection device due to heat or mechanical vibration by detecting the position information of the test mark based on the Has been issued. This technique mainly uses a first light source and a second light source having different wavelength bands, a reference plate, and a wavelength selection that transmits illumination light in a wavelength band emitted from the first light source and reflects illumination light emitted from the second light source. Reflective plate, focusing optics,
It has a dichroic mirror and two photodetectors.

The operation of this device is outlined below. First, the illumination light emitted from the first light source and the second light source are combined to illuminate the index plate, and the illumination light passing through the index plate and the condensing optical system is incident on the wavelength-selective reflection plate.
The illumination light emitted from the first light source passes through the wavelength-selective reflector to illuminate the test mark formed on the substrate.
The illumination light emitted from the second light source is reflected by the wavelength-selective reflector. The first reflected light generated by illuminating the test mark and the second reflected light reflected by the wavelength-selective reflector are multiplexed, propagate on the same optical axis, and return to the index plate and the condensing optical system. , The light is separated into a first reflected light and a second reflected light by a dichroic mirror, and each reflected light is detected by two detectors. Then, image information detected by the two detectors is subjected to image processing to obtain position information of the test mark. According to this technique, the first reflected light generated by illuminating the test mark and the second reflected light passing through the index plate pass on the same optical axis when passing through the focusing optical system. The drift stability is improved, and the detection accuracy of the relative position of the test mark with respect to the index mark provided on the index plate is improved. For more information on this technology,
See, for example, JP-A-9-219354.

[0012]

By the way, taking the manufacture of a semiconductor device as an example, the process of the 0.25 μm rule has been put to practical use at present, but the demand for miniaturization has further increased, and in the future the 0.1 μm rule will be required. In this process, a CPU (Central Processing Unit) and a RAM (Random Access Memory) are scheduled to be manufactured. Under such circumstances, it is required to further improve the detection accuracy of the mark to be detected. Generally, the alignment accuracy between the substrate and the reticle is required to be about 1/3 of the required resolution. Therefore, the alignment accuracy of about 30 nm is required for the resolution of about 0.1 μm. Therefore, the detection accuracy of the test mark must be kept as high as possible.

At present, in the manufacture of semiconductor devices, aluminum is generally used as a wiring material, and a mark to be inspected is illuminated using a light source having a wide wavelength band such as a halogen lamp as a substrate position detecting device. FIA for performing position measurement by image processing of the image of the test mark obtained as a result
In many cases, a system-type substrate position detecting device is used. Although the FIA type substrate position detecting device has been able to improve the drift stability by the above-described technique, it is necessary to secure the field of view of the position detecting device and the intensity of the image signal obtained from the optical images of the index mark and the test mark. In order to increase the degree of freedom of setting, two illumination lights having different wavelength bands are used, and the first reflected light and the second reflected light are used.
The reflected light is separated by a dichroic mirror, and it becomes necessary to detect each reflected light by two photodetectors. In this technique, the first reflected light and the second reflected light pass on the same optical axis when passing through the light-collecting optical system, so that the drift stability can be improved. By providing the dichroic mirror and the two photodetectors, it is conceivable that drift between the photodetectors affects the position detection accuracy.

Conventionally, the first reflected light and the second reflected light are separated by a dichroic mirror. However, the dichroic mirror cannot separate the wavelengths completely from each other. A part of the light may be included in the first reflected light, and when the first reflected light is converted into an image signal, a part of the second reflected light is superimposed on the first reflected light. Light was mixed in as noise, causing a deterioration in position detection accuracy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is intended for a case where an image of a test mark and an image of an index mark in different wavelength bands are separated and detected by different photodetectors. However, one image does not become a noise source of the other image and has excellent drift stability. As a result, it is possible to detect the position of the test mark formed on the test object with high accuracy. It is an object of the present invention to provide a position detecting device and a position detecting method which can be performed.

It is another object of the present invention to provide an exposure apparatus and an exposure method for performing an exposure process by aligning a test object using position information of a test mark obtained by such an apparatus and method. .

[0017]

Hereinafter, in the examples shown in this section, for ease of understanding, each constituent element of the present invention will be described with typical reference numerals shown in the drawings of the embodiments. The configuration of the present invention or each component requirement is not limited to those restricted by these reference numerals.

In order to solve the above-mentioned problem, the position detecting device of the present invention uses a test mark (A) formed on a test object (W).
M) is the same as the first light source (20) that emits the first illumination light (IL1) and the second light source (23) that emits the second illumination light (IL2) that illuminates the index mark (34). The first light beam (LB1) including the image of the test mark (AM) and the second light beam including the image of the index mark (34),
The light flux (LB2) is mainly composed of the first light flux (LB1) and slightly including the second light flux (LB2) and the second light flux (L2).
A separating means (40) for separating a light beam mainly including B2) into a light beam slightly including the first light beam (LB1); and the separating means (40).
A first sensor (41) into which a light beam mainly including the first light beam (LB1) separated by the light is incident, and a light beam mainly including the second light beam (LB2) separated by the separation means (40). And a second sensor (44) to which the light is incident, wherein the first illumination light (IL1) illuminates the test mark (AM) with the first illumination or the second illumination light (IL2). Index mark (34)
Shutter (2) for selectively blocking the second illumination for
6, 42) and the detection signal of the first sensor (41) in the first state in which the first illumination is blocked by the shutter (26, 42) and the second illumination is performed, or the shutter ( 26, 42) and a control means (13) for performing predetermined control using the detection signal of the second sensor (44) in the second state in which the second illumination is blocked and the first illumination is performed. It is characterized by having.

Here, the control means (13) stores the detection signal of the first sensor (41) in the first state as a first correction signal, or stores the second sensor in the second state. The detection signal of (44) is stored as a second correction signal, and the detection signal of the first sensor (41) in a state where the illumination by the illumination light (IL1, IL2) is not blocked by the shutters (26, 42). The position of the test mark (AM) is obtained based on the signal corrected by the first correction signal, or the position of the mark (AM) is not interrupted by the shutters (26, 42). The detection signal of the second sensor (44) is
Based on the signal corrected by the correction signal, the index mark (3
It is characterized in that the position of 4) is obtained.

According to the present invention, the separating means does not completely separate the first light beam and the second light beam, but separates the light beam mainly containing the first light beam and slightly containing the second light beam, and the second light beam. Lord and the first
Even if the control unit has a characteristic of separating the light beam into a light beam slightly containing the light beam, the control unit may control the second light beam slightly contained in the light beam.
The detection signal of the light beam is stored as a first correction signal, and the detection result of the light beam mainly including the first light beam and slightly including the second light beam by the first sensor is corrected by the first correction signal or slightly included in the light beam. Since the detection signal of the first light flux to be detected is stored as a second correction signal, and the detection result of the light flux mainly including the second light flux and slightly including the first light flux by the second sensor is corrected by the second correction signal. Since the influence of the first light beam or the second light beam slightly contained in the light beam can be removed, the position information of the test mark and the index mark can be detected with high accuracy.

Further, the control means (13) is provided with the first
In the state, a relationship between the position of the index mark (34) detected by the detection signal of the first sensor (41) and the position of the index mark (34) detected by the detection signal of the second sensor (44). Or in the second state, the position of the test mark (AM) detected by the detection signal of the first sensor (41) and the second position.
The amount of change in the relative position between the first sensor (41) and the second sensor (44) is determined based on the relationship with the position of the test mark (AM) detected by the detection signal of the sensor (44). It is characterized by:

According to the present invention, in a state where only the first illumination light is illuminated, the position information of the test mark of the first sensor and the second sensor is detected, or only the first illumination light is illuminated. In the state, the position information of the index marks of the first sensor and the second sensor is detected, and the first sensor and the second sensor are detected based on the position information of the detected test mark or based on the position information of the detected index mark. Since the change amount of the relative position with respect to the two sensors is obtained, even if the relative position between the first sensor and the second sensor changes while the apparatus is used, the change amount can be known.

Further, the position detecting device according to the present invention is characterized in that:
The wavelength of the illuminating light (IL1) and the wavelength of the second illuminating light (IL2) are made different from each other, and the separating means (40) sets the wavelength of the first illuminating light (IL1) and the second illuminating light (IL).
The first light flux (L) utilizing the difference in wavelength of 2).
It is preferable that the means is a means for separating a light beam mainly composed of B1) and a light beam mainly composed of the second light beam (LB2). In this case, the first illumination light (IL1) is visible light, Preferably, the illumination light (IL2) is infrared light. Further, the first sensor (41) and the second sensor (41)
Preferably, the sensor (44) is an image sensor.

Further, in the position detecting device according to the present invention, the control means does not interrupt the illumination by the illumination light by the shutters (26, 42). The positional relationship between the test mark (AM) detected by the detection signal and the index mark (34) is corrected based on the change amount.

According to the present invention, the first light beam and the second light beam propagating in the same optical path must be separated by the separating means, and each light beam must be detected by the first sensor and the second sensor. Even if the relative position between the first sensor and the second sensor is changed in the configuration that must be performed, the relative position between the detected test mark and the index mark is corrected based on the detected change amount. Mark position information can be obtained with high accuracy.

According to the position detecting method of the present invention, the test mark (AM) formed on the test object (W) is illuminated with the first illumination light (IL1), and the index mark (34) is set on the second mark (34). A first light beam (LB1) containing an image of the test mark (AM) and an second light beam (LB2) containing an image of the index mark (34), which are illuminated with the illumination light (IL2) and sent on the same optical path. Is divided into a light beam mainly including the first light beam (LB1) and slightly including the second light beam (LB2) and a light beam mainly including the second light beam (LB2) and slightly including the first light beam (LB1). A light beam mainly including the first light beam (LB1) is incident on a first sensor (41), and a light beam mainly including the second light beam (LB2) is incident on a second sensor (44); The first illumination for the test mark (AM) by the illumination light (IL1) is blocked and the second illumination light (I Said by 2) the index mark (3
4) using the detection signal of the first sensor (41) in the first state in which the second illumination is performed, or blocking the second illumination and the second sensor in the second state in which the first illumination is performed. It is characterized in that predetermined control is performed using the detection signal of (44).

Here, the predetermined control is to store a detection signal of the first sensor (41) in the first state as a first correction signal, or to store the detection signal of the second sensor (44) in the second state. ) Is stored as a second correction signal, and the detection signal of the first sensor (41) in a state where the illumination by the illumination light (IL1, IL2) is not interrupted is converted into a signal corrected by the first correction signal. Based on the test mark (A
M) or the position of the illumination light (IL1, IL1)
2) A process for obtaining the position of the index mark (34) based on a signal obtained by correcting the detection signal of the second sensor (44) with the second correction signal in a state where the illumination by 2) is not interrupted. I have.

According to the present invention, the separating means does not completely separate the first light beam and the second light beam, and separates the light beam mainly containing the first light beam and slightly containing the second light beam, and the second light beam. Lord and the first
Even in the case where the light beam has a characteristic of being separated into a light beam slightly including the light beam, the detection signal of the second light beam slightly included in the light beam is stored as the first correction signal, and the first light beam is mainly used as the first correction signal. The detection result of the light flux slightly including the second light flux by the first sensor is corrected by the first correction signal, or the detection signal of the first light flux slightly contained in the light flux is stored as the second correction signal, and the second light flux is stored. Since the detection result of the light beam mainly including the first light beam by the second sensor is corrected by the second correction signal, the influence of the first light beam or the second light beam slightly included in the light beam can be removed. Therefore, the position information of the test mark and the index mark can be detected with high accuracy.

Further, the predetermined control is performed based on the position of the index mark (34) detected by the detection signal of the first sensor (41) in the first state and the detection signal of the second sensor (44). Based on the relationship with the detected position of the index mark (34), or based on the second
In the state, the position of the test mark (AM) detected by the detection signal of the first sensor (41) and the position of the test mark (AM) detected by the detection signal of the second sensor (44) Is a process for calculating the amount of change in the relative position between the first sensor (41) and the second sensor (44) based on the relationship.

According to the present invention, the first light beam and the second light beam propagating in the same light path must be separated by the separating means, and each light beam must be detected by the first sensor and the second sensor. Even if the relative position between the first sensor and the second sensor is changed in the configuration that must be performed, the relative position between the detected test mark and the index mark is corrected based on the detected change amount. Mark position information can be obtained with high accuracy.

An exposure apparatus according to the present invention is an exposure apparatus for projecting and transferring an image of a pattern formed on a mask (R) onto a substrate (W), and is provided with the above-mentioned position detecting device.

Further, according to the exposure method of the present invention, the mask (R)
An exposure method for projecting and transferring an image of a pattern formed on a substrate (W) onto the substrate (W), wherein the substrate (W) is exposed after aligning the substrate (W) using the above-described position detection method. I have.

According to these inventions, the position information of the mark to be detected is detected with high accuracy by the position detecting device.
Since the position of the substrate with respect to the mask can be adjusted with high accuracy based on the detection result having high accuracy, it is extremely suitable for producing a finer device.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a position detecting device, a position detecting method, an exposure device, and an exposure method according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a view showing a schematic configuration of an exposure apparatus according to one embodiment of the present invention. In the present embodiment,
A step-and-repeat type exposure apparatus including an off-axis type alignment sensor as a position detection apparatus according to an embodiment of the present invention will be described as an example.
In the following description, the XYZ rectangular coordinate system shown in FIG. 1 is set, and the positional relationship of each member will be described with reference to the XYZ rectangular 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. In the XYZ coordinate system in the figure, the XY plane is actually set to a plane parallel to the horizontal plane, and the Z axis is set vertically upward.

In FIG. 1, when a control signal instructing emission of exposure light is output from a main control system 13 to be described later, an illumination optical system 1 emits exposure light EL having substantially uniform illuminance and outputs a reticle 2. Is irradiated. The optical axis of the exposure light EL is set parallel to the Z-axis direction. As the exposure light EL, for example, g-line (436 nm), i-line (365n)
m), KrF excimer laser (248 nm), ArF excimer laser (193nm), _{F 2} excimer laser (157 nm) is used. The reticle 2 has a fine pattern to be transferred onto a wafer (substrate) W coated with a photoresist, and is held on a reticle holder 3. The reticle holder 3 is supported so that it can move and minutely rotate in the XY plane on the base 4. A main control system 13 that controls the operation of the entire apparatus controls the operation of the reticle holder 3 via the driving device 5 on the base 4 to set the position of the reticle 2.

When the exposure light EL is emitted from the illumination optical system 1, the pattern image formed on the reticle 2 is transmitted through the projection optical system 6 to the projection optical system in the shot area set on the wafer W. 6 is projected on the shot positioned at the exposure center. The projection optical system 6 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 Z stage 8 via a wafer holder 7. The Z stage 8 is a stage for finely adjusting the position of the wafer W in the Z-axis direction. Also, Z stage 8
Are mounted on the XY stage 9. XY stage 9
Is a stage for moving the wafer W within the XY plane. Although not shown, a stage for slightly rotating the wafer W in the XY plane and a stage for changing the angle with respect to the Z axis to adjust the inclination of the wafer W with respect to the XY plane may be provided.

An L-shaped movable mirror 10 is attached to one end of the upper surface of the wafer holder 7, and a laser interferometer 11 is disposed at a position facing the mirror surface of the movable mirror 10. Although the illustration is simplified in FIG. 1, the movable mirror 10 is constituted by a plane mirror having a mirror surface perpendicular to the X axis and a plane mirror having a mirror surface perpendicular to the Y axis. In addition, the laser interferometer 11 emits two laser beams to the movable mirror 10 along the X axis.
A laser interferometer for the X-axis and a laser interferometer for the Y-axis for irradiating the movable mirror 10 with a laser beam along the Y-axis. One laser interferometer for the X-axis and one for the Y-axis. The X and Y coordinates of the wafer holder 7 are measured by the laser interferometer. Further, the rotation angle of the wafer holder 7 in the XY plane is measured based on the difference between the measurement values of the two X-axis laser interferometers.

The information on the X coordinate, the Y coordinate, and the rotation angle measured by the laser interferometer 11 is supplied to the stage drive system 12. These pieces of information are output from the stage drive system 12 to the main control system 13 as position information.
Controls the positioning operation of the wafer holder 7 via the stage drive system 12 while monitoring the supplied position information. Although not shown in FIG. 1, the reticle holder 3
Also, a movable mirror 10 and a laser interferometer 11 provided on the wafer holder 7 are provided, and information such as the XYZ position of the reticle holder 3 is input to the main control system 13.

An off-axis alignment sensor 14 is provided beside the projection optical system 6. The alignment sensor 14 is a position detecting device according to one embodiment of the present invention provided in the exposure apparatus according to one embodiment of the present invention, and is a position detecting device when applied to a FIA (Field Image Alignment) method. It comprises a portion 14a and an index objective portion 14b provided with an index plate and the like. Illumination light for illuminating the wafer W from the halogen lamp in the casing 15 via the optical fiber 16 is incident on the sensor main body 14 a, and further, from the infrared light source in the casing 17 via the optical fiber 18. Illumination light for illuminating an index plate provided in the index objective section 14b is incident. Here, the reason why the halogen lamp is used as the light source of the illumination light is that the wavelength range of the light emitted from the halogen lamp is 500 to 8.
This is because the wavelength range is 00 nm, which is a wavelength range in which 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. In order to illuminate the index plate, an infrared light source other than the halogen lamp is provided to secure the field of view of the alignment sensor 14 and to adjust the index mark formed on the index plate and the alignment mark AM formed on the wafer W. This is to increase the degree of freedom in setting the intensity of each image signal obtained from the optical image.

The illumination light that has entered the sensor body 14a is emitted to the index objective 14b. The illumination light from the halogen lamp emitted from the index objective unit 14b irradiates the upper surface of the wafer W. The alignment sensor 14 takes in the reflected light on the upper surface of the wafer W via the index objective part 14b, converts the detection result into an electric signal, and outputs it to the main control system 13. The illumination light from the infrared light source does not illuminate the wafer W, but outputs a detection result obtained by illuminating the index plate in the index objective unit 14b to the main control system 13. Although not shown, an irradiation optical system that supplies detection light for forming a pinhole image or a slit image toward the surface of the wafer W obliquely with respect to the optical axis AX, and the detection light Wafer W
An oblique-incidence focus position detection system is installed, which consists of a light-receiving optical system that re-images a pinhole image or the like on the vibration slit from the reflected light beam on the surface of the lens and receives the light beam transmitted through the vibration slit. . This focus position detection system supplies a focus signal corresponding to a positional deviation in the Z-axis direction of the surface of the wafer W with respect to the best imaging plane of the projection optical system 6 to the main control system 13, and the main control system 13 supplies the focus signal to the focus signal. Then, the Z stage 8 is driven in the Z-axis direction by the autofocus method. In this embodiment, the angle of a parallel flat glass (not shown) provided beforehand in the light receiving optical system is adjusted so that the image plane becomes the zero point reference, and the focus signal from the light receiving optical system becomes 0. It is assumed that autofocus is performed so that

The main control system 13 includes an alignment sensor 14
Signal processing is performed on the detection result output from the alignment sensor 14 based on the position information of the alignment mark AM formed on the wafer W and the position information of the index mark formed on the index plate. And the overall operation of the exposure apparatus is controlled based on the deviation amount and the position information output from the stage drive system 12. More specifically, the main control system 13 first outputs a drive control signal to the stage drive system 12 so that the alignment mark AM formed on the wafer W falls within the field of view of the alignment sensor 14. When the stage drive system 12 drives the XY stage 9, the detection results of the alignment sensor 14 and the position detection sensor are output to the main control system 13. The main control system 13 calculates a distance obtained by correcting the shift amount from the measurement center output from the alignment sensor 14 by the baseline amount, and outputs a drive control signal to the stage drive system 12 based on the calculated value. . Based on the drive control signal, the stage drive system 12 drives the XY stage 9 and the Z stage 8 in a stepping manner so that each shot area is accurately adjusted to the exposure position.

The outline of the configuration and operation of the exposure apparatus according to one embodiment of the present invention has been described above. Next, the alignment sensor 14, which is a position detecting apparatus according to one embodiment of the present invention, will be described in detail. FIG. 2 is a cross-sectional view showing the configuration of the alignment sensor 14 according to one embodiment of the present invention. In FIG. 2, the same members as those shown in FIG. 1 are denoted by the same reference numerals. 2, in a casing 15, a halogen lamp 20 that emits illumination light having a wavelength range of 500 to 800 nm, a wavelength limiting optical filter 21 that limits the wavelength range of the illumination light emitted from the halogen lamp 20, and a wavelength. Restriction optical filter 2
There is provided a condenser lens 22 for condensing the illumination light passing through 1 on one end of the optical fiber 16. Similarly, in the casing 17, an infrared light source 23 that emits illumination light in an infrared region whose wavelength region is different from the illumination light emitted from the halogen lamp 20, and illumination that is emitted from the infrared light source 23. A wavelength limiting optical filter for limiting the wavelength range of light;
8 is provided with a condenser lens 25 for condensing light at one end. FIG.
As shown in FIG. 2, the halogen lamp 15 and the infrared light source 23 are not provided in the sensor body 14a, but are separated from the sensor body 14a, and the illumination light is transmitted through the optical fibers 16 and 18 to the sensor. The reason why they are introduced into the main body 14a is that the halogen lamp 15 and the infrared light source 23 are heat sources, and if they are provided in the sensor main body 14b, it is not preferable in performing position measurement with high accuracy.

As shown in FIG. 2, the illumination light IL1 emitted from the halogen lamp 20 in the casing 15 is guided into the sensor body 14a from the other end of the optical fiber 16. This illumination light IL1 is condensed by a condenser lens 27 via a shutter 26, and is dichroic mirror inclined at an angle of 45 ° with respect to the optical path of the illumination light IL1 set parallel to the X-axis direction. 28. Dichroic mirror 28 reflects visible light,
The illumination light IL1, which is a visible light and has a wavelength selectivity for transmitting infrared light, is reflected by the dichroic mirror 28 in the -Z direction with almost no dimming, and then uniformly illuminates the field stop 29. As will be described later, the dichroic mirror 28 is attached to the sensor body 14 via the optical fiber 18.
Illumination light IL2 composed of infrared light introduced into a is incident from a direction orthogonal to illumination light IL1. Field stop 2
The illumination light IL1 that has passed through 9 is condensed by the relay lens 30 and enters the half prism 31 disposed at an inclination angle of 45 ° with respect to the optical path of the illumination light IL1. The illumination light IL1 reflected in the −X direction on the half mirror surface of the half prism 31 then passes through a window 14c provided on the lower side surface of the sensor main body 14a, and is then provided on the side surface of the index objective unit 14b. The light enters the target objective section 14b through the window 14d. As shown in FIG. 2, the sensor main body 1 is attached to a side surface of a projection optical system holding portion 6a provided on a side wall of the projection optical system 6.
4a is fixed, and the index objective section 14b is fixed to the bottom of the projection optical system holding section 6a.

Illumination light IL that has entered the index objective section 14b
1 forms a projection image of the other end surface of the optical fiber 16 on the entrance pupil plane 32 of the first objective lens 33,
3, and is incident on an index plate 35 made of a transparent glass plate on which an index mark 34 is formed. The illumination light IL1 that has passed through the index plate 35 is deflected in the -Z-axis direction by the epi-illumination prism 36, and the cold mirror 3 made of a transparent glass plate is used.
7 is incident. On the surface of the cold mirror 37, a visible light is transmitted, but a cold mirror film (hereinafter, referred to as a “CM film”) 37a that reflects infrared light is deposited, and the illumination light IL1, which is visible light, is almost dimmed. The light passes through the cold mirror 37 without being affected.

The cold mirror 37 is connected to the index objective section 14b.
Is configured to be able to finely move in the Z-axis direction by a cold mirror driving element 38 formed of a piezoelectric element or the like provided inside the main control system 13.
Is controlled by After passing through the cold mirror 37, the illumination light IL1 irradiates the alignment mark AM formed on the surface of the wafer W corresponding to the focal plane of the first objective lens 33 almost perpendicularly. The illumination area on the wafer W is set to a desired size by the field stop 29. The alignment mark AM is formed in a size of about 100 μm square, and its longitudinal direction is set in the Y-axis direction.
It has a one-dimensional pattern structure formed at a pitch of several μm in the X-axis direction. In the present embodiment, for the sake of simplicity, the case where the pattern of the alignment mark AM and the index mark 34 is one-dimensional will be described as an example.
Using the alignment mark AM and the index mark formed of a two-dimensional lattice-like pattern or the like can obtain the position information in the X-axis direction and the Y-axis direction only by measuring the alignment mark AM once. It is preferable from the viewpoint of improving the throughput.

The illumination light IL1 applied to the alignment mark AM is reflected and diffracted by the alignment mark AM.
The optical path of the illumination light IL1 is reversed from above the wafer W as the alignment mark detection light LB1. The alignment mark detection light LB1 is incident on the cold mirror 37 and the CM film 3
After passing through the cold mirror 37 with almost no dimming at 7a, it is deflected in the X-axis direction by the epi-illumination prism 36,
The light enters the first objective lens 33 via the index plate 35. A Fraunhofer diffraction image by the alignment mark AM is formed on the entrance pupil plane 32 of the first objective lens 33 by the alignment mark detection light LB1. On the index plate 35, an index mark 34 having a one-dimensional (or two-dimensional) slit-like pattern structure of the same size as the alignment mark AM is formed, and the index plate 35 is a first objective lens. It is located near 33. Therefore, the spread of the illumination light IL1 for irradiating the alignment mark AM and the alignment mark detection light LB1 from the alignment mark AM on the index plate 35 is substantially equal to that of the first objective lens 3.
The effective diameter is 3, that is, about ten and several mm. On the contrary,
The size of the index mark 34 on the index plate 35 is as small as about 100 μm square, and is about 10 ⁻⁴ in terms of area ratio. Therefore, the illumination light IL1 passing through the index plate 35 can uniformly irradiate the alignment mark AM without being substantially affected by light shielding or diffraction by the index mark 34. Similarly, when the alignment mark detection light LB1 returning from the alignment mark AM passes through the index plate 35, it is hardly affected by light shielding or diffraction by the index mark 34, so that the entrance pupil plane of the first objective lens 33 The index mark 34 hardly affects the alignment mark image of the 32 alignment marks AM.

The alignment mark detection light LB 1 emitted from the entrance pupil plane 32 of the first objective lens 33 passes through the half prism 31 and enters the second objective lens 39. The alignment mark detection light LB1 condensed by the second objective lens 39 enters the dichroic mirror 40. The dichroic mirror 40 has a wavelength selectivity that reflects visible light and transmits infrared light similarly to the dichroic mirror 28 described above. Therefore, the alignment mark detection light LB
Reference numeral 1 denotes an alignment mark image of the alignment mark AM on the imaging surface of a two-dimensional imaging element 41 such as a two-dimensional CCD, which is reflected by the dichroic mirror 40 without being dimmed. As shown in FIG. 2, the alignment mark detection light LB1 and the index mark detection light L
B2 is separated by the dichroic mirror 40 after passing on the same optical path. It reflects a few percent of external light and transmits a few percent of visible light.
If the alignment mark AM is a one-dimensional mark, the image sensor 41 may be a one-dimensional CCD or the like. The alignment mark image of the alignment mark AM is hardly affected by the "shaking" by the index mark 34,
It can be considered as ideal imaging. Therefore, the position of the alignment mark AM is accurately detected from the alignment mark image. The light intensity of the alignment mark image of the alignment mark AM is converted into an electric signal by the image sensor 41 and output to the main control 13.

On the other hand, the illumination light IL2 composed of infrared light emitted from the infrared light source 26 is condensed by the condenser lens 43 via the shutter 42, and is condensed by the dichroic mirror 2
8 pass through the field stop 29 without being reduced, and are condensed by the relay lens 30 to enter the half prism 31. Although not shown, the other end of the optical fiber 18 is supported so as to be finely movable in a direction perpendicular to the Z direction. Therefore, the telecentricity of the illumination light IL2 is adjusted by changing the position of the other end of the optical fiber 18 in the direction perpendicular to the Z axis. The illumination light IL2 that has entered the half prism 31 is reflected by the half prism 31, and forms a projected image of the other end of the optical fiber 18 on the entrance pupil plane 32 of the first objective lens 33. The diameter of the luminous flux of the illumination light IL2 emitted from the first objective lens 33 is approximately several tens of mm, which is substantially equal to the effective diameter of the first objective lens 33, and is on the index plate 35 disposed immediately after the first objective lens 33. It is sufficiently possible to uniformly irradiate the index mark 34 having a size of about 100 μm. The pattern structure of the index mark 34 is such that the phase of the transmitted light is 1 in the concave and convex portions having the same periodicity as the alignment mark AM.
This is a two-dimensional (or one-dimensional) phase pattern that differs by 80 °. Therefore, of the illumination light IL2, the light beam illuminating the index mark 34 is transmitted and diffracted, and most of the index light is converted into only ± 1 order two (four in the case of a two-dimensional mark) diffracted light beam. It becomes the mark detection light LB2.

After passing through the index plate 35, the index mark detection light LB2 made of infrared light is deflected in the -Z direction by the epi-illumination prism 36 and is irradiated on the cold mirror 37. As described above, the CM film 37a deposited on the surface of the cold mirror 37 has an optical property of transmitting visible light and reflecting infrared light. Therefore, the CM film 3 of the cold mirror 37
The index mark detection light LB2 reflected without being dimmed in 7a returns to the epi-illumination prism 36 again, is deflected in the X direction, passes through the index plate 35 without being affected by the index mark 34, and Re-enter the objective lens 33. By the index mark detection light LB2, a Fraunhofer diffraction image by the index mark 34 is formed on the entrance pupil plane 32 of the first objective lens 33. The cold mirror 37 on which the CM film 37a is formed as described above is configured so that the position in the Z-axis direction can be adjusted by the cold mirror driving element 38, and the position of the cold mirror 37 in the Z-axis direction can be changed. Thereby, the position of the index mark 34 in the Z-axis direction is substantially adjusted.

In this case, the optical path length from the index mark 34 to the reflecting surface of the epi-illumination prism 36 is D ₂ ,
From a reflecting surface the light path length to the CM film 37a of the cold mirror 37 and _{D 1,} the optical path length from the index mark 34 to the CM film 37a through the incident prism 36 _{L 1} (= _D 1
+ And D _2), the position of the cold mirror 37 and the index plate 35 so that the optical path length L ₂ from the surface of the wafer W to CM film 37a faces the cold mirror 37 is approximately equal is set. Therefore, when viewed from the first objective lens 33, it appears that the index mark 34 exists on the surface of the wafer W. That is, the index mark 34 for the first objective lens 33
Is equivalent to being on the focal plane of the first objective lens 33.

The index mark detection light LB2 emitted from the first objective lens 33 passes through the half prism 31,
The light enters the objective lens 39. The index mark detection light LB2 condensed by the second objective lens 39 passes through the dichroic mirror 40 with almost no dimming, and is a two-dimensional image sensor 44 composed of a two-dimensional CCD for the index mark 34.
The index mark image of the index mark 34 is formed on the image pickup surface of. If the index mark 34 is a one-dimensional mark, the image sensor 44 may be a one-dimensional CCD or the like. The light intensity of the index mark image of the index mark 34 is converted into an electric signal by the image sensor 44 and output to the main control system 13. As previously mentioned,
After the alignment mark detection light LB1 and the index mark detection light LB2 pass on the same optical path, they are separated by the dichroic mirror 40. The reflection and transmission characteristics of the dichroic mirror 40 reflect 100% of visible light, Does not transmit 100%, but reflects several percent of infrared light and transmits several percent of visible light. Note that the image sensor 44 is arranged as close to the dichroic mirror 40 as possible. The focusing of the index mark image of the index mark 34 on the image sensor 44 is performed by the index plate 35,
This is performed by changing the arrangement of the cold mirror 37, the image sensor 44, and the like.

Next, the shutter 26 and the shutter 42 block the illumination light IL1 emitted from the other end of the optical fiber 16 and the illumination light IL2 emitted from the other end of the optical fiber 18, respectively. The opening / closing operation is controlled by the opening / closing control device 45 based on a control signal output from the main control system 13. The opening / closing device 45 controls the shutter 26 and the shutter 4 under the control of the main control system 13.
2 are both in the open state, the shutter 26 and the shutter 42 are both in the closed state, or one of the shutters 26 and 42 is in the open state and the other is in the closed state. Do.

When the shutter 26 is open and the shutter 42 is closed, the illumination light IL2 does not illuminate the index plate 35, so that only the alignment mark detection light LB1 enters the dichroic mirror 40. Hereinafter, this illumination state (second state) is referred to as a visible light illumination state. In the visible light illumination state, the light intensity of the alignment mark image of the alignment mark detection light LB1 is converted into an electric signal by the image sensor 41 and output to the main control 13.
At this time, as described above, the dichroic mirror 40
The reflection and transmission characteristics of (1) reflect 100% of visible light but do not transmit 100% of infrared light. Therefore, the light intensity of the alignment mark image of the alignment mark detection light LB1 transmitted through the dichroic mirror 40 is electrically The signal is converted into a signal and output to the main control system 13. Hereinafter, in the visible light illumination state, the electric signal output from the imaging element 41 is referred to as a visible light illumination detection image signal,
The electric signal output from the image sensor 44 is called a visible light illumination noise image signal.

Conversely, when the shutter 42 is open and the shutter 26 is closed, the illumination light IL1 does not illuminate the alignment mark AM, so that only the index mark detection light LB2 enters the dichroic mirror 40. I do. Hereinafter, this illumination state (first state) is referred to as an infrared light illumination state. In the infrared light illumination state, the light intensity of the index mark image of the index mark detection light LB2 is converted into an electric signal by the image sensor 44 and output to the main control 13, and the index slightly reflected by the dichroic mirror 40. The light intensity of the index mark image of the mark detection light LB2 is converted into an electric signal by the image sensor 41 and output to the main control system 13. Hereinafter, in the infrared light illumination state, the electric signal output from the imaging element 41 is referred to as an infrared light illumination noise image signal,
The electric signal output from the imaging element 44 is called an infrared light illumination detection image signal.

Next, the main control system 13 shown in FIG. 1 will be described in detail. FIG. 3 is a block diagram schematically showing an internal configuration of main control system 13. As shown in FIG. 3, the main control system 13 includes a control unit 50, a storage unit 51, a position calculation unit 55,
And an interface 56. The control section 20 outputs a control signal to each section of the exposure apparatus to control the operation. For example, the illumination optical system 1 is connected to the casings 15 and 17,
It controls whether or not to emit the exposure light EL to the illumination optical system 1 and determines whether or not to emit the illumination light to the halogen lamp 20 in the casing 15 and the infrared light source 23 in the casing 17. Control. Further, a control signal for controlling the open / close state of the shutter 26 and the shutter 42 is output to the open / close control device 45. The storage unit 51 temporarily stores the electric signals output from the imaging device 41 and the imaging device 44. The storage unit 51 includes a first correction signal storage unit 52, a second correction signal storage unit 53, and a It has an amount storage unit 54. The first correction signal storage section 52 and the second correction signal storage section 53 are sections for storing correction signals when the image processing is performed to obtain the position information of the alignment mark AM and the index mark 34, respectively. Reference numeral 54 denotes an image sensor 41 and an image sensor 4 provided in the alignment sensor 14.
This is a part for storing the amount of change in the relative position with respect to No. 4.

The position calculating section 55 receives the electric signals of the alignment mark image of the alignment mark AM and the index mark image of the index mark 34 temporarily stored in the storage section 51 and inputs the signals via the interface 56. The position information of the center of the alignment mark image of the alignment mark AM with respect to the center of the index mark image of the index mark 34 is detected by calculating the position information of the XY stage 9 from the laser interferometer 11. Further, the image sensor 4
Since the magnification between the images on the imaging surfaces 1 and 44 and the surface of the wafer W is known in advance, the amount of displacement is converted into the amount of displacement on the wafer W. Then, the measured value of the laser interferometer 11 at the time of the measurement is added to the converted position shift amount to obtain a stage coordinate system of the alignment mark AM (a coordinate system indicating the position of the XY stage 9).
The position at is calculated. In this case, when the center of the alignment mark image of the alignment mark AM coincides with the center of the index mark image of the index mark 34, the position of the center of the alignment mark AM is determined by the alignment sensor 11.
Can be regarded as the center of measurement. Interface 56
Is connected to the control unit 50 and the position calculation unit 55, and is connected to the stage drive system 12 in FIG.
The control signal output from 0 is output to the stage drive system 12, and the position information input via the stage drive system 12 is output to the control unit 50 and the position calculation unit 55.

Further, the control unit 50 controls the opening and closing operations of the shutters 26 and 42 shown in FIG. 2 so that the visible light output from the image pickup devices 41 and 44 in the visible light illumination state or the infrared light illumination state. Based on the illumination detection image signal and the visible light illumination noise image signal, or the infrared light illumination noise image signal and the infrared light illumination detection image signal, the amount of change in the relative position between the imaging device 41 and the imaging device 44 is obtained.

Next, an operation for detecting the position information of the alignment mark AM formed on the wafer W by using the alignment sensor 14 provided in the exposure apparatus of the present embodiment having the above configuration will be described. First, the exposure apparatus of the present embodiment periodically performs a baseline check for accurately measuring the distance between the measurement center of the alignment sensor 14 and the exposure center.
4, the relative position between the image sensor 41 and the image sensor 44 changes. If the relative position changes, the position detection accuracy of the alignment mark AM decreases. Therefore, the alignment sensor 14 of the present embodiment
Calculates the amount of change in the relative position between the image sensor 41 and the image sensor 44 at the time of the baseline check in order to improve the position detection accuracy of the alignment mark AM. Hereinafter, this processing will be described.

[Process for Calculating Change in Relative Position between Image Sensor 41 and Image Sensor 44] FIG. 4 is a flowchart showing a process for calculating the change in relative position between image sensor 41 and image sensor 44. Before the processing is started, the main control system 1
The control unit 50 in the XY control unit 3
The stage 9 is driven to move the alignment mark AM formed on the wafer W into the field of view of the alignment sensor 14. When the process starts, the control unit 50 outputs a control signal, and outputs the illumination light IL1 from the halogen lamp 20 to the control unit 50.
The illumination light IL2 is emitted from the infrared light source 23 (step S1). When the illumination lights IL1 and IL2 are emitted, the illumination light IL1 illuminates the alignment mark AM formed on the wafer W, and the illumination light IL2 illuminates the index mark 34 formed on the index plate 35. Next, the control unit 50 outputs a control signal to the opening / closing control device 45, sets the shutter 26 to the closed state, sets the shutter 42 to the open state, and sets the infrared light illumination state (step S2).

From the sensor body 14b to the index objective 14b
Is transmitted through the first objective lens 33 and illuminates the index mark 34 formed on the index plate 35 to become index mark detection light LB2. This index mark detection light LB2 is transmitted to the cold mirror 3
7 and is reflected. The reflected index mark detection light LB2 passes through the epi-prism 36, the index plate 35, and the first objective prism 33, and then passes through the half prism 31 to enter the second objective lens 39. Second objective lens 39
Most of the index mark detection light LB2 condensed by the light passes through the dichroic mirror 40 without being dimmed,
An index mark image of the index mark 34 is formed on the imaging surface of the imaging element 44, and the slight index mark detection light LB2 reflected by the dichroic mirror 40 also forms the imaging element 41.
An index mark image is formed on the imaging surface of.

The image pickup devices 41 and 44 convert the image of the index mark formed on the image pickup surface into an electric signal and output it as an infrared light illumination noise image signal and an infrared light illumination detection image signal, respectively. The infrared light illumination noise image signal and the infrared light detection image signal output from the imaging elements 41 and 44 are input to the main control system 13 and are temporarily stored in the storage unit 51 (step S3). FIG. 5 is a diagram illustrating an example of the index mark 34. When the index mark shown in FIG. 5 is used, the infrared light illumination noise image signal and the infrared light detection image signal output from the imaging elements 41 and 44 are as shown in FIG. FIG. 6 is a diagram showing an infrared light illumination noise image signal and an infrared light illumination detection image signal when the index mark shown in FIG. 5 is used in the infrared light illumination state. Since the dichroic mirror 40 has a reflection and transmission characteristic of transmitting the index mark detection light LB2 almost without dimming and slightly reflecting the index mark detection light LB2, the infrared light illumination noise shown in FIG. The signal intensity of the image signal is low, and the signal intensity of the infrared light illumination detection image signal shown in FIG. still,
The interval between the scales shown on the vertical axis in FIG.
The intervals between the scales shown on the vertical axis are the same.

Next, the control section 50 outputs a control signal for causing the position calculation section 55 to perform image processing. When the control signal is input, the position calculation unit 55 reads out the infrared light illumination noise image signal and the infrared light illumination detection image signal temporarily stored in the storage unit 51, and based on the respective image signals. The position information of the index mark 34 is calculated (step S
4). The position information of the index mark 34 calculated from each of the infrared light illumination noise image signal and the infrared light illumination detection image signal is:
Since the position information is calculated based on the index mark detection light LB2, the position information calculated from the first image signal and the position information calculated from the second image signal should indicate the same position. However, when the relative position between the image sensor 41 and the image sensor 44 changes, the respective position information becomes different. The control unit 50 reads out the position information calculated by the position calculation unit 55, calculates the amount of change in the relative position of the image sensor 41 and the image sensor 44 from the positional information (Step S5), and calculates the change in the calculated relative position. The amount is stored in the change amount storage unit 54 in the storage unit 51 (step S
6). With the above processing, the processing for obtaining the amount of change in the relative position between the image sensor 41 and the image sensor 44 ends. still,
In the above description, the case where the amount of change in the relative position of the image sensor 41 and the image sensor 44 is calculated from the index mark image obtained in the infrared light illumination state, but the alignment obtained in the visible light illumination state is described. The amount of change in the relative position between the image sensor 41 and the image sensor 44 may be calculated from the mark image.

[Correction Signal Calculation Processing] Next, a description will be given of processing for obtaining a correction signal used for obtaining position information of the alignment mark AM and the index mark 34. This process is performed when the above-described baseline check is performed, or immediately before the exposure process of the first wafer W of the lot is performed. FIG. 7 is a flowchart showing a process for obtaining a correction signal used when obtaining the position information of the alignment mark AM and the index mark 34. Before the processing is started, the control unit 50 in the main control system 13
The XY stage 9 is driven through the alignment sensor 2 and the alignment mark AM formed on the wafer W is aligned with the alignment sensor 1.
Move it in the field of view of 4. When the process starts, the control unit 50 outputs a control signal, and causes the halogen lamp 20 to emit the illumination light IL1 and the infrared light source 23 to emit the illumination light IL2 (step S10). If the process shown in FIG. 7 is performed simultaneously with the process of calculating the amount of change in the relative position between the image sensor 41 and the image sensor 44 shown in FIG. 4,
The processing in step S10 is omitted.

By emitting the illumination lights IL1 and IL2, the illumination light IL1 illuminates the alignment mark AM formed on the wafer W, and the illumination light IL2 illuminates the index mark 34 formed on the index plate 35. . Next, the control unit 5
0 outputs a control signal to the opening / closing control device 45, sets the shutter 42 to the open state, sets the shutter 26 to the closed state, and sets the shutter to the infrared light illumination state (step S1).
1).

In the state of infrared light illumination, most of the index mark detection light LB2 condensed by the second objective lens 39 passes through the dichroic mirror 40 without being dimmed, and An index mark image of the index mark 34 is formed, and the slight index mark detection light LB2 reflected by the dichroic mirror 40 forms an index mark image on the imaging surface of the imaging element 41. In this state, the infrared light illumination noise image signal and the infrared light illumination detection image signal are output from the image pickup device 41 and the image pickup device 44 to the main control unit 13, respectively.
0 is the first correction signal storage unit 52 in the storage unit 51 that stores only the infrared light illumination noise image signal output from the imaging device 41
It is stored as a correction signal (step S12). When the index mark 34 shown in FIG. 5 is used, the first correction signal stored in the first correction signal storage unit 52 is the infrared light illumination noise image signal shown in FIG.

Next, the control unit 50 outputs a control signal to the opening / closing control device 45 to open the shutter 26,
The shutter 42 is set to a closed state, and the visible light illumination state is set (step S13). The illumination light IL1 incident on the index objective section 14b from the sensor body 4a passes through the first objective lens 33, the index plate 35, the epi-illumination prism 36, and the cold mirror 37 to illuminate the alignment mark AM of the wafer W. Alignment mark detection light L generated by illuminating alignment mark AM
B1 is incident on the second objective lens 39 via the cold mirror 37, the reflecting prism 36, the index plate 35, the first objective lens 33, and the half prism 31. The alignment mark detection light LB1 collected by the second objective lens 39
Most of the light is reflected by the dichroic mirror 40 without being dimmed and forms an alignment mark image of the alignment mark AM on the imaging surface of the imaging device 41. However, the slight alignment mark detection light LB1 transmitted through the dichroic mirror 40 Forms an alignment mark image on the imaging surface of the imaging element 44. In this state, the visible light illumination detection image signal and the visible light illumination noise image signal from the imaging device 41 and the imaging device 44 are respectively transmitted to the main control unit 13.
The control unit 50 in the main control unit 13 stores only the visible light illumination noise image signal output from the image sensor 44 in the second correction signal storage unit 53 in the storage unit 51 as a second correction signal. (Step S14). With the above processing, the processing for obtaining the correction signal used for obtaining the position information of the alignment mark AM and the index mark 34 ends.

FIG. 8 is a diagram showing an example of the alignment mark AM. When the alignment mark AM shown in FIG. 8 is used, the visible light illumination detection image signal and the visible light illumination noise image signal output from each of the imaging elements 41 and 44 are as shown in FIG. FIG. 9 is a diagram showing a visible light illumination detection image signal and a visible light illumination noise image signal when the index mark shown in FIG. 8 is used in the visible light illumination state. As shown in FIG. 9, the dichroic mirror 40
Reflects the alignment mark detection light LB1 almost without dimming, and slightly reflects the alignment mark detection light LB1.
9A, the signal intensity of the visible light illumination detection image signal shown in FIG.
The signal intensity of the visible light illumination noise image signal shown in (b) is low. Note that the scale interval shown on the vertical axis in FIG. 9A is the same as the scale interval shown on the vertical axis in FIG. 9B, and FIGS. The interval is the same as the interval of the scale shown on the vertical axis. When the alignment mark AM shown in FIG. 8 is used, the second correction signal stored in the second correction signal storage unit 53 is the visible light illumination noise image signal shown in FIG. 8B.

[Alignment Mark Position Information Detection Processing] Next, the amount of change in the relative position between the imaging element 41 and the imaging element 44 obtained by the processing shown in FIG.
The operation of detecting the position of the alignment mark AM using the first correction signal and the second correction signal obtained by the processing described in (1) will be described in detail. FIG. 10 is a flowchart illustrating a process of detecting the position of the alignment mark AM using the amount of change in the relative position between the image sensor 41 and the image sensor 44, the first correction signal, and the second correction signal. In the present embodiment, the image sensor 41 and the image sensor 4
4, the first correction signal and the second correction signal are already stored in the change amount storage unit 54 and the first correction signal storage unit 5.
2 and the case where they are stored in the second correction signal storage unit 53 will be described. When the process is started, the control unit 50 in the main control system 13 outputs a control signal to cause the halogen lamp 20 to emit the illumination light IL1 and the infrared light source 23 to emit the illumination light IL2 (Step S20). Next, the control unit 50 controls the wafer introduction device (not shown)
A control signal for introducing a wafer is output to introduce a wafer (step S21). Thereafter, the control unit 50 outputs a control signal to the opening / closing control device 45, and sets the shutter 26 and the shutter 42 to the open state (Step S2).
2). By opening the shutter 26 and the shutter 42, both the illumination light IL1 and the illumination light IL2 are incident from the sensor body 14a to the index objective 14b. Next, the control unit 50 drives the XY stage 9 via the stage drive system 12, and moves the alignment mark AM formed on the wafer W into the field of view of the alignment sensor 14 (Step S23).

The illumination light IL1 incident on the index objective section 14b
Are the first objective lens 33 and the index plate 3 as described above.
5, illuminate the alignment mark AM on the wafer W by passing through the epi-illumination prism 36 and the cold mirror 37, respectively. On the other hand, the illumination light IL2 incident on the index objective portion 14b
Is transmitted through the first objective lens 33, illuminates the index mark 34 formed on the index plate 35, and emits the index mark detection light LB2.
And the cold mirror 37 via the epi-illumination prism 36
And is reflected.

The alignment mark detection light LB1 generated by illuminating the alignment mark AM overlaps the index mark detection light LB2 reflected by the cold mirror 37 when passing through the cold mirror 37, and the alignment mark detection light LB1 and the index mark Detection light LB2
After passing through the reflecting prism 36, the index plate 35, and the first objective prism 33, the light passes through the half prism 31 and the second objective lens 39 and enters the dichroic mirror 40. Most of the alignment mark detection light LB1 is reflected by the dichroic mirror 40 to form an alignment mark image on the image pickup surface of the image pickup device 41, and most of the index mark detection light LB2 is transmitted through the image pickup surface of the image pickup device 44. A small index mark detection light LB2 forms an index mark image on the imaging surface of the imaging device 41, and a slight alignment mark detection light LB1 forms an alignment mark on the imaging surface of the imaging device 44. A mark image is formed.

The image pickup device 41 and the image pickup device 44 each output an electric signal based on the image formed on the image pickup surface to the main control system 13. (Step S24).
Hereinafter, the electric signals output from the imaging element 41 and the imaging element 44 when the shutter 26 and the shutter 42 are in the open state are referred to as a first image signal and a second image signal, respectively. The first image signal stored in the storage unit 51 is as shown in FIG.
This is a signal obtained by overlapping the visible light illumination detection image signal shown in FIG. 6A and the infrared light illumination noise image signal shown in FIG.
When the position information is obtained, the infrared light illumination noise image signal shown in FIG. 6A becomes noise. Further, the second image signal output from the image sensor 44 is a signal obtained by overlapping the visible light illumination noise image signal shown in FIG. 9B and the infrared light detection image signal shown in FIG. 6B. FIG. 9 (b) is a signal for obtaining position information of the index mark 34 by performing image processing.
The visible light illumination noise image signal shown in FIG. Thus, the slight index mark detection light LB2 reflected by the dichroic mirror 40 and the slight alignment mark detection LB1 transmitted through the dichroic mirror 40
Are the index mark 34 and the alignment mark A, respectively.
Noise occurs when the position information of M is detected, which hinders detection of the position information with high accuracy. In this embodiment,
Using the first correction signal stored in the first correction signal storage unit 52 and the second correction signal stored in the second correction signal storage unit 53, a process for removing these noises is performed.

First, the control unit 50 reads out the first image signal temporarily stored in the storage unit 51,
By reading the first correction signal stored in the correction signal storage unit 52 and processing the first image signal using the first correction signal, the dichroic mirror 40 included in the first image signal is read.
A process is performed to remove noise based on the slight index mark detection light LB2 reflected by. That is, the first image signal is the same as the infrared light illumination noise image signal shown in FIG.
6A is a signal obtained by overlapping the visible light illumination detection image signal shown in FIG. 6A, and as described above, the first correction signal
Since it is the infrared light illumination noise image signal shown in (a), the overlapping signal is processed by using the first correction signal, and FIG.
The infrared light noise image signal shown in FIG.
Correction is made only to the visible light illumination detection image signal shown in FIG. Then, position information of the alignment mark AM is calculated based on the corrected first image signal (step S2).
5).

Next, the control unit 50 reads out the second image signal temporarily stored in the storage unit 51,
By reading the second correction signal stored in the correction signal storage unit 53 and processing the second image signal using the second correction signal, the dichroic mirror 40 included in the second image signal is processed.
Is performed to remove noise based on the slight alignment mark detection light LB1 that has passed through. That is, the second image signal is the same as the infrared light illumination detection image signal shown in FIG.
9B is a signal in which the visible light illumination noise image signal shown in FIG. 9B overlaps, and as described above, the second correction signal is the signal shown in FIG.
Since the image signal is the visible light illumination noise image signal shown in FIG. 9B, the overlapped signal is processed using the second correction signal, and FIG.
The visible light illumination noise image signal shown in FIG.
Correction is made only to the infrared light illumination detection image signal shown in (b). Then, position information of the index mark 34 is calculated based on the corrected second image signal (step S26).

Further, the control unit 50 reads out the amount of change in the relative position between the image sensor 41 and the image sensor 44 stored in the change amount storage unit 54 of the storage unit 51, and calculates the alignment calculated in steps S25 and S26. A process of correcting the position information of the mark AM and the position information of the index mark 34 is performed. As described above, in the process of using the alignment sensor 14, the image sensor 41 and the image sensor 44 are used.
May change, and when this change occurs, the position information of the alignment mark AM and the index mark 34 is shifted by the amount of change in the relative position between the image sensor 41 and the image sensor 44. A process of correcting this variation is performed to improve the accuracy (step S2).
7).

By performing the processing in step S27,
Since the displacement between the position information of the alignment mark AM and the position information of the index plate 34 based on the amount of change in the relative position between the image sensor 41 and the image sensor 44 has been corrected, the position of the corrected alignment mark AM is corrected. The amount of deviation of the alignment mark AM from the measurement center of the alignment sensor 14 is calculated based on the information and the position information of the index plate 34 (step S28). By the above processing, the imaging device 4
Using the amount of change in the relative position between the first and second image sensors 44, the first correction signal, and the second correction signal.
The process of detecting the position of is ended.

When the process shown in FIG. 10 is completed, the control unit 50 drives the XY stage 9 via the interface 56 and the stage drive system 12, and the control unit 50 proceeds to step S in FIG.
The wafer W is moved in the XY plane by a distance obtained by correcting the shift amount calculated in the process 28 by the baseline amount, and the center of the defined area (shot area) set on the wafer W is accurately positioned at the exposure center. Match. Then, the control unit 50 outputs a control signal to the illumination optical system 1 to emit the exposure light EL, and transfers the pattern formed on the reticle 2 to the wafer W.
The shot area set above is exposed. At the time of exposure, steps S23 to the exposure operation are repeatedly performed.

The embodiments described above are described for facilitating the understanding of the present invention, but not for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, the present invention can be applied to a step-and-scan type reduction projection type exposure apparatus, a mirror projection type, a proximity type, a contact type, etc.

Further, not only an exposure apparatus used for manufacturing a semiconductor element and a liquid crystal display element, but also an exposure apparatus used for manufacturing a plasma display, a thin-film magnetic head, and an image pickup element (such as a CCD), and a reticle or a mask. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern onto a glass substrate, a silicon wafer, or the like in order to manufacture a substrate. That is, the present invention is applicable irrespective of the exposure method and application of the exposure apparatus.

In the above embodiment, the wafer W
The case where the position information of the alignment mark AM formed above is detected has been described as an example.
The present invention can also be applied to the case of detecting position information of a mark formed on a mark or a mark formed on a glass plate. Furthermore, in the above embodiment, the case where the mark detection device of the present invention is applied to an off-axis type alignment sensor has been described as an example. The position detection of the present invention can be applied to all devices that detect a position.

[0082] g-line or i-line as the exposure light EL of the exposure device of the present embodiment, or KrF excimer laser, ArF excimer laser, had using light emitted from the _{F 2} excimer laser, KrF excimer laser (248 nm) , A
rF excimer laser (193nm), _{F 2} laser (1
57 nm) as well as charged particle beams such as X-rays and electron beams. For example, when an electron beam is used, thermionic emission type lanthanum hexaborite (LaB ₆ ), tantalum (Ta) is used as an electron gun.
Can be used. Further, for example, a single-wavelength laser in the infrared or visible region oscillated from a DFB semiconductor laser or a fiber laser is amplified by a fiber amplifier doped with erbium (or both erbium and ytterbium), and further, a nonlinear optical crystal. May be used to convert the wavelength to ultraviolet light. Note that an ytterbium-doped fiber laser is used as the single-wavelength oscillation laser.

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 shown in FIG. 1, the illumination optical system 1, the alignment system for the reticle R (not shown), the wafer alignment system including the wafer stage 7, the moving mirror 10, and the laser interferometer 11, the projection optical system 6, and the like. After the components are assembled electrically, mechanically, or optically,
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. 11 is a flowchart for producing 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. FIG.
As shown in (1), first, in step S30 (design step), a function design of a device (for example, a circuit design of a semiconductor device) is performed, and a pattern design for realizing the function is performed. Subsequently, in step S31 (mask manufacturing step), a mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step S32 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

Next, in step S33 (wafer process step), actual circuits and the like are formed on the wafer by lithography using the mask and the wafer prepared in steps S30 to S32. Then
In step S34 (assembly step), step S
The wafer is processed into chips using the wafer processed in 33.
Step S34 includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). Finally, in step S35 (inspection step), inspections such as an operation confirmation test and a durability test of the device manufactured in step S34 are performed. After these steps, the device is completed and shipped.

The magnification of the projection optical system may be not only the reduction system but also any one of the same magnification and the 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 the glass material.
_{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 the wafer stage or reticle holder, 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 and an armature unit having two-dimensionally arranged coils opposed to each other 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 the above, a frame member may be used to mechanically escape to the floor (ground). 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 JP-A-8-330224 (US S / N 08 / 416,558). Is also good.

[0090]

As described above, according to the present invention,
The separating means does not completely separate the first light beam and the second light beam,
Even if it has a characteristic of separating a light beam mainly containing the first light beam and slightly containing the second light beam and a light beam mainly containing the second light beam and slightly containing the first light beam, The means stores a detection signal of the second light beam slightly contained in the light beam as a first correction signal, and performs a first correction of a detection result of the light beam mainly including the first light beam and slightly including the second light beam by the first sensor. The detection result of the first light flux slightly corrected by the signal or the light flux slightly stored in the light flux is stored as the second correction signal, and the detection result of the second light flux mainly including the second light flux and slightly including the first light flux is obtained by the second sensor. Since the correction is performed by the second correction signal, the influence of the first light beam or the second light beam slightly contained in the light beam can be removed, so that the position information of the test mark and the index mark can be detected with high accuracy. This has the effect.

Further, according to the present invention, in a state where only the first illumination light is illuminated, the position information of the test mark of the first sensor and the second sensor is detected, or only the first illumination light is detected. In an illuminated state, the position information of the index marks of the first sensor and the second sensor is detected, and the first sensor is detected based on the detected position information of the test mark or based on the detected position information of the index mark. Since the amount of change in the relative position between the first sensor and the second sensor is determined, it is possible to know the amount of change even if the relative position between the first sensor and the second sensor changes during use of the device. There is an effect that can be.

According to the present invention, the first light beam and the second light beam propagating in the same light path must be separated by the separating means, and each light beam must be detected by using the first sensor and the second sensor. Even if the relative position between the first sensor and the second sensor is changed in the configuration that must be performed, the relative position between the detected test mark and the index mark is corrected based on the detected change amount. There is an effect that the position information of the mark can be obtained with high accuracy.

Further, according to the present invention, the position information of the test mark is detected with high accuracy by the position detecting device or position detecting method of the present invention, and the mask information is detected with high accuracy based on the detection result having high accuracy. Since the substrate can be aligned, it is very suitable for producing a finer device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of an alignment sensor according to an embodiment of the present invention.

FIG. 3 is a block diagram schematically showing an internal configuration of a main control system 13.

FIG. 4 is a flowchart illustrating a process for calculating a change amount of a relative position between the imaging device 41 and the imaging device 44.

FIG. 5 is a diagram showing an example of an index mark 34.

6 is a diagram showing an infrared light illumination noise image signal and an infrared light illumination detection image signal when the index mark shown in FIG. 5 is used in an infrared light illumination state.

FIG. 7 shows an alignment mark AM and an index mark 34.
9 is a flowchart showing a process for obtaining a correction signal used when obtaining position information of FIG.

FIG. 8 is a diagram illustrating an example of an alignment mark AM.

9 is a diagram showing a visible light illumination detection image signal and a visible light illumination noise image signal when the index mark shown in FIG. 8 is used in a visible light illumination state.

FIG. 10 is a flowchart illustrating a process of detecting a position of an alignment mark AM using a change amount of a relative position between an image sensor 41 and an image sensor 44, a first correction signal, and a second correction signal.

FIG. 11 is a flowchart when a device is produced using the exposure apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 ... Main control system (control means) 20 ... Halogen lamp (1st light source) 23 ... Infrared light source (2nd light source) 26, 42 ... Shutter 34 ... Index mark 40 ... Dichroic mirror (separation means) 41 ... Image sensor (First sensor) 44 ... imaging element (second sensor) 50 ... control unit (control means) 51 ... storage unit (control means) 52 ... first correction signal storage unit (control means) 53 ... second correction signal storage unit (Control means) 54 Change amount storage unit (Control means) 55 Position calculation unit (Control means) W ... Wafer (test object, substrate) R ... Reticle (mask) AM ... Alignment mark (Test mark) IL1 ... Illumination light (first illumination light) IL2 ... Illumination light (second illumination light) LB1 ... Alignment mark detection light (first light flux) LB2 ... Index mark detection light (second light flux)

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2F065 AA03 BB02 BB27 CC20 FF04 GG02 HH13 JJ03 JJ05 JJ26 LL00 LL02 LL04 LL22 LL30 PP12 PP23 QQ31 5F046 BA04 ED02 FA03 FA06 FA10 FB04 FB10 FB11 FB13 FB16

Claims (12)

[Claims] A first light source that emits a first illumination light that illuminates a test mark formed on the test object; and a second light source that emits a second illumination light that illuminates an index mark. A first light beam including the image of the test mark and a second light beam including the image of the index mark, which are transmitted along an optical path, and a light beam mainly including the first light beam and slightly including the second light beam; A separating unit that mainly separates the first light beam into light beams that slightly include the first light beam; a first sensor into which a light beam that mainly includes the first light beam separated by the separating device is incident; A second sensor to which a light beam mainly including the second light beam is incident, wherein the first mark or the second mark is used to illuminate the test mark with the first light. For selectively blocking the second illumination for the camera Using the detection signal of the first sensor in a first state in which the first illumination is blocked by the shutter and the second illumination is performed, or the second illumination is blocked by the shutter and the first illumination is used. Control means for performing predetermined control using the detection signal of the second sensor in the second state in which the position detection is performed. 2. The control means stores a detection signal of the first sensor in the first state as a first correction signal, or stores the detection signal of the second sensor in the second state.
A detection signal of the sensor is stored as a second correction signal, and the detection is performed based on a signal obtained by correcting the detection signal of the first sensor with the first correction signal in a state where the illumination by the illumination light is not blocked by the shutter. Determining the position of a mark, or determining the position of the index mark based on a signal obtained by correcting the detection signal of the second sensor with the second correction signal in a state where illumination by the illumination light is not blocked by the shutter. The position detecting device according to claim 1, wherein: 3. The control device according to claim 1, wherein the control unit determines a position of the index mark detected by a detection signal of the first sensor in the first state and a position of the index mark detected by a detection signal of the second sensor. The relationship between the position of the test mark detected by the detection signal of the first sensor in the second state and the position of the test mark detected by the detection signal of the second sensor in the second state. 2. The position detecting device according to claim 1, wherein a change amount of a relative position between the first sensor and the second sensor is obtained based on the position. 4. The wavelength of the first illumination light and the wavelength of the second illumination light are made different from each other, and the separating means determines that the wavelength of the first illumination light is different from the wavelength of the second illumination light. 4. The position detecting device according to claim 1, wherein the position detecting device is a unit that separates a light beam mainly including the first light beam and a light beam mainly including the second light beam using the light beam. 5. The position detecting device according to claim 4, wherein the first illumination light is visible light, and the second illumination light is infrared light. 6. The position detecting device according to claim 1, wherein the first sensor and the second sensor are image sensors. 7. The method according to claim 1, wherein the control unit is configured to control the first and the second lamps in a state where the illumination by the illumination light is not blocked by the shutter.
The position detecting device according to claim 3, wherein a positional relationship between the test mark and the index mark detected by a detection signal of a second sensor is corrected based on the amount of change. 8. A test mark formed on a test object is a first mark.
Illuminating with the illumination light, illuminating the index mark with the second illumination light, and forming a first light flux including the image of the test mark and a second light flux including the image of the index mark transmitted through the same optical path, A light beam mainly including one light beam and slightly including the second light beam and a light beam mainly including the second light beam and slightly including the first light beam are incident on the first sensor. A light flux mainly composed of the second light flux is incident on a second sensor, a first illumination of the test mark by the first illumination light is cut off, and a second illumination of the index mark by the second illumination light is performed. Using a detection signal of the first sensor in the first state of performing the first illumination, or using a detection signal of the second sensor in the second state of interrupting the second illumination and performing the first illumination. A position detection method characterized by performing control. 9. The method according to claim 6, wherein the predetermined control is to store a detection signal of the first sensor in the first state as a first correction signal, or to store the second detection signal in the second state.
The detection signal of the sensor is stored as a second correction signal, and the position of the test mark is determined based on a signal obtained by correcting the detection signal of the first sensor with the first correction signal in a state where the illumination by the illumination light is not interrupted. Or a process of calculating the position of the index mark based on a signal obtained by correcting the detection signal of the second sensor with the second correction signal in a state where the illumination by the illumination light is not interrupted. A position detecting method according to claim 8. 10. The method according to claim 1, wherein the predetermined control is performed in the first state with a position of the index mark detected by a detection signal of the first sensor and a position of the index mark detected by a detection signal of the second sensor. Or the relationship between the position of the test mark detected by the detection signal of the first sensor and the position of the test mark detected by the detection signal of the second sensor in the second state. 9. The position detecting method according to claim 8, wherein the processing is for obtaining a change amount of a relative position between the first sensor and the second sensor based on the following. 11. An exposure apparatus for projecting and transferring an image of a pattern formed on a mask onto a substrate, comprising: the position detection apparatus according to claim 1. Description: 12. An exposure method for projecting and transferring an image of a pattern formed on a mask onto a substrate, wherein the substrate is exposed after aligning the substrate using the position detection method according to claim 8, 9, or 10. An exposure method, comprising: