JP2002134391A - Apparatus and method for measuring position, aligner and method for manufacturing micro device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized and inexpensive apparatus and a method for measuring position, capable of measuring with a high measurement accuracy, to provide an exposure device having the apparatus, and to further provide a method for manufacturing a micro device using the aligner. SOLUTION: A plate alignment sensor 20a has an illumination optical system for illuminating marks formed on an object with a detection light, a photodetecting optical system for photodetecting a light obtained by illuminating the marks, with the detection light and a processor for obtaining positional information of the marks, based on the photodetected result of the photodetecting optical system. The sensor 20a also has an index plate 46, disposed at a position substantially conjugate to a focus surface FC of the detection light in the illumination optical system and having an index mark 47 of a predetermined shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position measuring apparatus and method, an exposure apparatus, and a method for manufacturing a micro device. TECHNICAL FIELD The present invention relates to a position measuring device and method used when manufacturing a semiconductor device, an exposure apparatus, and a micro device manufacturing method.

[0002]

2. Description of the Related Art Semiconductor devices, imaging devices, liquid crystal display devices,
Alternatively, in the manufacture of a micro device such as a thin film magnetic head, an image of a pattern formed on a mask or a reticle (hereinafter, referred to as a mask) is referred to as a wafer or a glass plate (hereinafter, these are collectively referred to as a substrate). An exposure device for transferring the image to the substrate is used. For example, a liquid crystal display element (LC
When manufacturing D), a so-called step-and-repeat type exposure apparatus (hereinafter, referred to as a stepper) is often used. This stepper exposes a pattern of an LCD formed on a mask to a predetermined area of a glass plate (hereinafter, referred to as a plate) as a substrate, and then steps the stage on which the plate is mounted by a predetermined distance. Then, by exposing another area of the plate again and repeating this operation for all the areas set on the plate, an apparatus for transferring the image of the pattern formed on the mask to the entire plate. is there.

When an image of a pattern formed on a mask is transferred to a plate, it is necessary to precisely match the position of the plate with the position of the image of the pattern. In recent years, with the miniaturization of the pattern formed on the plate, high alignment accuracy between the mask and the plate is required. For example, about one-tenth to several tenths of the minimum line width of the pattern formed on the plate Alignment accuracy is required. For this reason, marks for position measurement are formed on a mask or a plate, and the exposure apparatus includes a position measurement device that measures the position information of these marks with high accuracy.

A major type of position measuring device that measures position information using position measuring marks formed on a plate is classified into LSA (Lase) from the viewpoint of measurement principle.
r Step Alignment (FIA) method or FIA (Field Image Alignment)
ent) method. The LSA type position measurement device is a position measurement device that irradiates a laser beam onto a mark of a dot row formed on a plate and measures position information of the mark by using diffracted / scattered light. An FIA type position measuring device illuminates a mark using a light source having a wide wavelength band such as a halogen lamp, converts an image of the obtained mark into an image signal, and performs image processing to obtain position information of the mark. Is a position measuring device for determining the asymmetric mark formed on the aluminum layer or the plate.

The above-described LSA type position measuring apparatus needs to include a laser light source in the apparatus in order to use the laser light, and further have an optical system for shaping and relaying the laser light emitted from the laser light source. In general, since a He-Ne laser is used as a laser light source, a large amount of heat is generated, and it is necessary to take measures to avoid the influence of measurement errors due to heat. Further, since the laser light from the laser light source is relayed to the mark on the plate by an optical system, the laser light is easily affected by mechanical vibration, heat and the like. Furthermore, since monochromatic laser light emitted from the He-Ne laser is used for mark position measurement, it is susceptible to interference by the resist applied on the plate, which has the disadvantage of worsening measurement errors. . On the other hand, in the FIA type position measuring device, as described above, a light source having a wide wavelength bandwidth such as a halogen lamp is used, so that the influence of resist interference can be reduced. Further, since the light emitted from the halogen lamp can be drawn into the position measuring device by using an optical fiber by arranging the light source outside, a thermal effect can be reduced.

When the position measuring devices are classified from the viewpoint of an observation method in position measurement, a TTL (through-the-lens) for measuring position information of a mark on a plate via a projection optical system is used.
The lens) system, a TTM (through-the-lens) system that simultaneously observes a mark formed on a plate and a mark formed on a mask via a projection optical system and detects a relative positional relationship between the two.
The mask) system, and an off-axis system that directly measures position information of a mark on a plate without using a projection optical system. In the manufacture of a liquid crystal display element, an off-axis type position measuring device is generally used to handle a large plate. Therefore, an exposure apparatus used in the manufacture of a liquid crystal display element is usually provided with an off-axis type and a FIA type position measuring apparatus.

Here, the off-axis system is used and the FI
The configuration of the optical system of the conventional position measuring device of the A type will be described. FIG. 21 shows an off-axis system,
FIG. 9 is a diagram showing a configuration of an optical system of a conventional position measuring device of the IA system. In FIG. 21, illumination light IL1 is supplied from an external illumination light source such as a halogen lamp via an optical fiber 100.
0 is derived. The illumination light source is disposed outside the chamber of the exposure apparatus, and the illumination light is selected at a predetermined wavelength by a dichroic filter or the like. The illumination light IL10 is incident on a half mirror 104 which branches light transmission and light reception via a field stop 102 for limiting an illumination field of view and an illumination relay lens 103 via a condenser lens 101 in order. Illumination light IL10 reflected by half mirror 104
Is irradiated to the region including the mark 107 formed on the plate 106 via the objective lens 105.

The mark 10 formed on the plate 106
The reflected light obtained by irradiating the illumination light 7 with the illumination light IL10 passes through the objective lens 105, the half mirror 104, the second objective lens 1
08 and an image on the index plate 110 via the mirror 109 in this order. Therefore, the image of the mark 106 formed on the plate 106 is formed on the index plate 110. An index mark having a predetermined shape is formed on the index plate 110. An image of the mark 107 formed on the index plate 110 and an image of the index mark formed on the index plate 110 are transmitted via relay lenses 111 and 112 to a charge coupled device (CCD).
image) on the imaging surface of the imaging element 113 such as ice).

The image of the mark 107 formed on the imaging surface of the image sensor 113 and the image of the index mark on the index plate 110 are photoelectrically converted into image signals and output to a processing system (not shown). A processing system (not shown) performs image processing on the input image signal, for example, the center position of the index mark and the mark 107.
Of the index mark and the center position of the mark 10
The position information of the mark 107 is obtained based on the relative relationship between the mark 107 and the center position. Thus, the position information of the mark 107 is measured.

[0010] Here, the first in which the above-mentioned index plate 110 is provided.
The reason for this is to provide a reference when measuring the position information of the mark 107. Considering an ideal case where the position of the imaging surface of the imaging element 113 does not change at all, the imaging element 1
Since the spatial position of the imaging surface 13 does not change, the positional information of the mark 107 can be measured based on the spatial position of the imaging surface. However, actually, the position of the image sensor 113 may fluctuate due to vibration or the like. When the distance from the detection surface (the surface of the plate 106) to the imaging surface of the imaging element 113 is set to be long, the influence of the vibration becomes large. In order to avoid such a problem, the index plate 110 is provided in the optical path between the detected surface and the image sensor 113, and the position information of the mark 107 is measured based on the position of the index plate 110, thereby changing the position of the image sensor 113. However, the position information of the mark 107 can be obtained accurately.
In this case, in order to maintain the measurement accuracy, it is necessary to set the optical path length between the detected surface and the reference plate 110 as short as possible.

A second reason for providing the index plate 110 is to prevent the influence on the detection accuracy due to the electrical jump of a signal generated when a CCD is used as the image pickup device 113. As is well known, a CCD converts an image formed on an imaging surface into an image signal while scanning the image in a scanning direction.
During scanning, a part of the image signal may be shifted in the scanning direction due to an electrical jump. This shift is equivalent to an image signal obtained when the marks are laterally shifted, and must be avoided from the viewpoint of preventing erroneous detection. When the index plate 110 is provided and the position information of the mark 107 is obtained from the relative relationship between the image of the mark 107 and the image of the index mark, even if a part of the image signal is shifted in the scanning direction due to an electrical jump. Since the relative positional relationship between the mark image and the index mark image does not change, erroneous detection is reduced.

In an exposure apparatus having an off-axis type and a FIA type position measuring apparatus, a measurement area is set outside a projection area of a projection optical system for irradiating a plate with an image of a pattern formed on a mask. Therefore, it is necessary to previously obtain a baseline amount which is an interval between the measurement center of the position measurement device and the center of the projected image of the pattern formed on the mask (the exposure center). The measurement of the baseline amount is performed using a reference mark provided on a stage on which the plate is placed.

Conventionally, when measuring the baseline amount, the stage is moved to dispose the reference mark at a predetermined position in the projection area of the projection optical system, and is formed on the reference mark and the mask via the projection optical system. The center of the projected image of the pattern formed on the mask (exposure center) is obtained by simultaneously observing the position measurement marks. Next, the stage is moved to dispose the reference mark in the measurement area of the position measurement device, and the position measurement device measures the position information of the reference mark to determine the measurement center of the position measurement device. Then, the distance between the exposure center and the measurement center is obtained based on the obtained exposure center and measurement center, and the stage position when the exposure center and the measurement center are obtained, thereby obtaining the baseline amount.

When performing the exposure process, after the plate is conveyed on the stage, the mark formed on the plate is measured by the position measuring device, the shift amount from the measurement center of the mark is obtained, and this shift amount is used as a base. After the plate is moved by the distance corrected by the line amount, the relative position between the plate and the mask is accurately aligned, and then the mask is irradiated with exposure light to expose the image of the pattern formed on the mask via the projection optical system. Transfer to the plate.

In recent years, the size of a plate on which an exposure process is performed has been increased. From the viewpoint of suppressing an increase in cost required for the exposure process and preventing a decrease in accuracy, it is necessary to minimize the size of the stage. For this reason, a reference mark that moves up and down is provided at the position where the plate is placed, and the baseline amount is measured using the reference mark that moves up and down. Also, with the increase in the size of the plate, an exposure apparatus that exposes the entire plate using a plurality of masks has been used. For example, 4
When a single mask is used, the reference mark is moved upward in a state where the plate is not placed on the stage, and the reference pattern is moved approximately to the plate surface position when the plate is placed on the stage. It is necessary to dispose them at the same position and measure the exposure center for each mask in order to determine the base line amount for each mask.

A method of measuring the position information of each mask is described in Japanese Patent Application Laid-Open No. 61-143760, for example, by using a reference mark provided on a stage and a light receiving sensor provided below the reference mark. The relative position between the formed position detection mark and the reference mark is detected, and the slit mark formed as the reference mark is emitted from below (stage side) and projected as in JP-A-63-284814. There is a method of detecting a relative position with respect to a slit mark formed on a mask through an optical system by a light receiving sensor provided in the illumination optical system.

[0017]

By the way, a microdevice such as a liquid crystal display device performs a development process after an exposure process, and performs various processes using a patterned photoresist as a mask. Manufactured repeatedly. Therefore, a metal film, a transparent electrode film, or the like may be formed on the plate, and the level difference of the mark formed on the plate varies depending on the processing performed. When measuring such marks with a position measuring device,
The contrast and light intensity of an image obtained by irradiating the mark with the illumination light IL10 also vary.

Therefore, in the position measuring device, the plate 10
In order to suppress the aberration generated in the optical system between the mark 107 formed on the image pickup device 6 and the image sensor 113, the objective lens 1
05, second objective lens 108, and relay lens 11
It is necessary to design aberrations in the optical system including the lenses 1 and 112. In the conventional position measuring device shown in FIG.
Therefore, it is necessary to provide the index plate 110 at a position conjugate with the surface to be detected with respect to the objective lens 105 and the second objective lens 108.
It was necessary to design the index plate 110 and the image sensor 113 using the 112 so as to be conjugate.

Naturally, as the number of relay lenses increases, the influence is exerted on aberrations, and furthermore, manufacturing errors and the like of each relay lens are accumulated and reflected on measurement errors. When manufacturing a liquid crystal display element, since a large plate is used as compared with a semiconductor substrate, considering the bending of the plate in a state where the plate is mounted on a stage, a position measuring device in a direction orthogonal to the plate surface is taken into consideration. It is necessary to set a longer movable distance. This movement is necessary for adjusting the focal position of the position measuring device (the image forming position of the illumination light IL10) to the detected surface (the surface of the plate 106). As described above, in the conventional position measurement device, if the aberration design of the optical system arranged in the optical path from the plate surface to the image pickup device 113 via the index plate 110 is required, it is necessary to use a considerably large optical system. There was a problem. When the size of the optical system is increased, it is necessary to mechanically stabilize the entire apparatus, which causes a problem of high cost.

The present invention has been made in view of the above circumstances, and provides a position measuring apparatus and method which are inexpensive, small, and capable of measuring with high measurement accuracy, and include the position measuring apparatus. Providing an exposure apparatus,
It is another object of the present invention to provide a method for manufacturing a micro device using the exposure apparatus.

[0021]

Means for Solving the Problems In order to solve the above problems, the invention according to the first aspect provides an object (P, FM1, FM
2) Irradiation optical systems (45, 48,) for irradiating the marks (AM1 to AM4, 30b) formed with the detection light (IL1).
49, 50) and a light receiving optical system (49, 50, 51, 52, 53, 5, 5) for receiving light obtained by irradiating the mark (AM1 to AM4, 30b) with the detection light (IL1).
4) and the light receiving optical system (49, 50, 51, 52, 5)
3, 54) based on the light receiving result.
AM4, 30b) and a processing system (15) for obtaining position information of the irradiation optical system (4).
5, 48, 49, 50) and the detection light (IL
An index plate (46) having an index mark (47) having a predetermined shape is disposed at a position substantially optically conjugate with the imaging position (FC) of (1). According to the present invention, the mark formed on the object is irradiated with the image of the index mark having a predetermined shape, and the image of the mark and the image of the index mark are picked up by the image pickup devices (53, 54). Mark position information is measured based on the relative positional relationship between the mark image and the index mark image. Therefore, a relay optical system for forming an image of a mark on the index plate is not required as compared with a case where the index plate is arranged in the light receiving optical system, so that the apparatus is inexpensive and can be downsized. Furthermore, since the position information of the mark is measured based on the relative relationship between the image of the mark and the image of the index mark, the position information can be obtained with high measurement accuracy as in the conventional position measurement device in which the index plate is arranged in the light receiving optical system. Information can be measured. Here, the index mark (47) is a first light shielding unit (47a) that shapes the detection light (IL1) into a rectangular shape.
And a part of the detection light (IL1) shaped into a rectangular shape,
Second light-shielding portion (47b) for shielding light into an annular shape having four sides
And a cross-shaped light-shielding portion (q1-q) is provided at each of the four corners of the second light-shielding portion (47b).
4) is formed. When the index mark (47) has such a shape, the marks (AM1 to AM4, 30b) are formed by arranging U-shaped mark elements (37a, 37b) in a first direction (X-axis direction). And a second mark formed by arranging the U-shaped mark elements (37c, 37d) in a direction (Y-axis direction) orthogonal to the first direction (X-axis direction). And the U-shaped mark element (3) forming the first mark element pair and the second mark element pair.
7a to 37d) are such that their openings (38a to 38d) face in opposite directions and are separated from each other by at least the length of the image of the second light-shielding portion (47b) at the imaging position of the detection light (IL). L-shaped mark elements (39a to 39d) having a shape arranged and further having a longitudinal direction set in the first direction (X-axis direction) and the second direction (Y-axis direction).
And the L-shaped mark element (39a
To 39d) are each a U-shaped mark element (37a).
To 37d) are preferably arranged adjacent to two different combinations. Further, the invention according to the first aspect provides the mark (AM1 to AM4,
Prior to the measurement of the position information of 30b), the image of the index mark (47) is irradiated on a predetermined reflection surface (FM1, FM2), and the image of the index mark (FM1, FM2) reflected by the reflection surface (FM1, FM2) is obtained. Im2) with the image sensor (53,
54), the method further includes a step (S31a to S31h) of previously obtaining the position information of the image (Im2) of the index mark on the imaging surface of the image sensor (53, 54), wherein the marks (AM1 to AM4) are obtained. , 30b), the marks (AM1 to AM4, 3)
0b) The position information of the image (Im2) of the index mark on the imaging surface obtained prior to the measurement, and the image (I) of the mark captured by the image sensor (53, 54).
m1), wherein the position information of the marks (AM1 to AM4, 30b) is measured based on the relative relationship with the position information in the imaging plane. According to the present invention, the position information of the index mark on the imaging surface is measured in advance using the reflector, and when the position information of the mark formed on the object is measured, the mark imaged by the image sensor is used. Is obtained, and position information of the mark is measured based on a relative relationship between the position information and the position information of the index mark measured in advance. Therefore, when irradiating the image of the index mark to the mark, the contrast of the image of the index mark changes according to the surface state of the object, and the position information of the index mark cannot be measured. Even when the relative relationship cannot be determined based on the image of the index mark formed on the imaging surface of the image sensor and the image of the mark, the position information can be measured with high accuracy. Further, the invention according to the first aspect provides the detection light (I
A first correction optical system (60) for correcting chromatic aberration generated in the irradiation optical system (45, 48, 49, 50) due to a wavelength difference in the wavelength band of L1), and the detection light (IL1)
Is irradiated onto the object (P, FM1, FM2), and the light receiving optical system (4
9, 50, 51, 52, 53, 54), and a second correction optical system (61) for correcting chromatic aberration. Here, the first correction optical system (60) includes the irradiation optical system (45, 48, 49, 5).
At least one irradiation-side adjustment member (60a, 60b) rotatable with respect to the optical axis of the irradiation optical system (45, 48, 49, 50) in order to adjust the correction amount of the chromatic aberration of 0).
The second correction optical system (61) includes a light-receiving optical system (49) for adjusting a correction amount of chromatic aberration of the light-receiving optical system (49, 50, 51, 52, 53, 54). , 5
0, 51, 52, 53, 54) at least one light receiving side adjustment member (61a, 61b) rotatable with respect to the optical axis.
It is preferable to have According to these inventions, there are provided the first correction optical system for correcting the chromatic aberration generated in the irradiation optical system and the second correction optical system for correcting the chromatic aberration generated in the light receiving optical system, and the correction amount is adjustable. Therefore, chromatic aberration caused when using a broadband detection light can be prevented or reduced according to the amount of aberration in order to reduce the measurement error of the position information of the mark due to the multiple interference on the surface of the object which occurs according to the surface state of the object. Therefore, it is possible to prevent a decrease in position measurement accuracy. Further, the invention according to the first aspect provides the detection light (IL1) for the object (P, FM1, FM2).
It is characterized by further comprising adjusting means (70, 71) for adjusting the incident direction. Further, the invention according to the second aspect provides the light receiving optical systems (49,
50, 51, 52, 53, 54) to detect the relative displacement of the first reference mark for each wavelength (S72, S74), and the first displacement detection process (S72, From the detection result of S74), the light receiving optical system (4
9, 50, 51, 52, 53, 54) and an irradiation optical system (45, 48, 49, 5).
0), light of a plurality of different wavelengths from the second reference mark (47b) is received by the light receiving optical system (49, 50, 5).
1, 52, 53, 54) to detect the relative positional deviation of the second reference mark (47b) for each wavelength (S82, S84), and the second deviation detecting step (S82). , S84) from the detection result of the irradiation optical system (4).
5, 48, 49, and 50) (S8)
8) irradiating a detection surface (IL1) including light of a plurality of different wavelengths to the surface to be inspected using the irradiation optical system (45, 48, 49, 50); The light irradiated from the test surface is received through the light receiving optical system (49, 50, 51, 52, 53, 54), and the position information of the detection mark formed on the test surface is obtained. And a mark detecting step of detecting. Further, the invention according to the third aspect provides an object (P, FM
1, FM2) and marks (AM1 to AM1) formed on the object (P, FM1, FM2).
AM4) is irradiated with detection light (IL1), and light from the marks (AM1 to AM4) is used to detect the mark (A).
M1 to AM4) and an optical system for measuring position information (45, 48, 49, 50, 51, 52, 53, 5)
4) a reference member (13X, 13Y) fixed to the substrate stage (PS); and a reference member (13X, 13Y).
Y) The mark (A) caused by an installation error or a manufacturing error of
In order to correct an error in the position information of M1 to AM4), the irradiation direction of the detection light (IL1) to the marks (AM1 to AM4) according to an installation error or a manufacturing error of the reference members (13X, 13Y). Or the adjusting means (7
0, 71). According to the invention, a light receiving step of irradiating detection light on a mark on an object placed on a stage with a reference member and receiving light from the mark, and measuring position information of the reference member Measuring step, a detecting step of obtaining the position information of the mark based on the light receiving information from the light receiving step and the measurement information from the measuring step, and an error of the object caused by an installation error or a manufacturing error of the reference member. In order to correct the error of the position information, the adjustment is performed by performing an adjustment step of adjusting the irradiation direction or the position of the detection light to the mark according to an installation error or a manufacturing error of the reference member. The exposure apparatus of the present invention includes an illumination optical system (1, 2, 3, 4, 5,
6, 7, 6, 8, 9, 10, 11), the mask (M1 to M4) is irradiated with illumination light emitted from the mask (M1).
To M4) are projected onto the projection optical system (P
L) via a substrate (P) through a mark (AM1 to A1) formed on the substrate (P).
M4) the above-described position measurement device for measuring the position information,
Based on the measurement result of the position measuring device, the mask (M
1 to M4) and positioning means (15, 16X, 16Y) for performing relative positioning of the substrate (P). The method for manufacturing a micro device according to the present invention includes a step of measuring position information of the substrate (P) using the above-described position measurement method, and a step of: Relative alignment of the mask (M)
1 to M4) with illumination light, and the masks (M1 to M4) are illuminated.
4) transferring an image of the pattern formed on the substrate (P) via a projection optical system (PL) onto the substrate (P); and developing the substrate (P) to which the pattern has been transferred. It is characterized by.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, with reference to the drawings, a position measuring apparatus and method, an exposure apparatus, and a micro device manufacturing method according to embodiments of the present invention will be described in detail. FIG. 1 is a perspective view showing the overall configuration of an exposure apparatus according to an embodiment of the present invention including a position measuring device according to an embodiment of the present invention. In the present embodiment, a case where a pattern of a liquid crystal display element is formed as the masks M1 to M4 is used and an image of the pattern is transferred to the plate P by an exposure apparatus of a step-and-repeat method is described as an example. Will be explained. 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. XYZ
The orthogonal coordinate system is set so that the X axis and the Y axis are parallel to the stage PS, and set in a direction orthogonal to the Z axis stage PS (a direction parallel to the optical axis of the projection optical system PL). I have. In the XYZ coordinate system in the figure, the XY plane is actually set as a plane parallel to the horizontal plane, and the Z axis is set vertically upward.

At a first focal position of the elliptical mirror 1, a light source 2 such as an ultra-high pressure mercury lamp for supplying exposure light of g-line (436 nm) and i-line (365 nm) is arranged. Is condensed by the elliptical mirror 1 and reflected by the mirror 3, and then converged to the second focal position of the elliptical mirror 1. Then, the light enters the collector lens 4 and is converted into a parallel light flux. A light-reducing filter 5 is disposed between the mirror 3 and the collector lens 4 so as to be able to advance and retreat with respect to the optical path. The neutral density filter 5 suppresses the amount of exposure light reflected by the mirror 3, and is provided, for example, to adjust the amount of light detected by the photoelectric detector 19b. Although not shown, it is preferable to provide a wavelength selection filter in the optical path between the mirror 3 and the collector lens 4 that allows only the exposure light of a predetermined wavelength to pass.

The exposure light transmitted through the collector lens 4 is converted into a light beam having a uniform illuminance distribution by a fly-eye integrator 6. The fly-eye integrator 6 is composed of a large number of positive lens elements, and forms a light source image having the same number of positive lens elements on its exit side to form a substantial surface light source. Although not shown in FIG. 1, the exit surface of the fly-eye integrator 6 has a σ value for determining the illumination condition (on the pupil plane with respect to the aperture diameter of the pupil of the projection optical system PL described later). The aperture member for setting the ratio of the aperture of the light source image at the point (a) is disposed.

A light beam from a large number of light source images formed by the fly-eye integrator 6 passes through a half mirror 7 and a lens 8 to increase or decrease the size of an opening S and to adjust a blind 9 for adjusting the irradiation range of exposure light. Irradiate. Exposure light having passed through the opening S of the blind 9 passes through a lens 10 and is reflected by a mirror 11 to enter a condenser lens (not shown).
Is formed on the mask M1 placed on the mask stage MS, and a desired range of the mask M1 is illuminated. The replacement of the mask placed on the mask stage MS is performed by a mask changer (not shown). still,
The elliptical mirror 1, the light source 2, the mirror 3, the collector lens 4, the neutral density filter 5, the fly-eye integrator 6, the half mirror 7, the lens 8, the blind 9, the lens 10, the mirror 11, and the condenser lens (not shown) are illumination optics. Form a system.

The image of the pattern existing in the illumination area of the mask M1 is transferred to a plate P as an object (substrate or photosensitive substrate) placed on the stage PS via the projection optical system PL.
Transcribed above. The projection optical system PL is provided with a lens controller (not shown) that controls optical characteristics such as imaging characteristics to be constant in response to environmental changes such as temperature and atmospheric pressure. In FIG. 1, the plate P is indicated by a broken line, which indicates a state when the plate P is mounted on the stage PS. The stage PS includes an XY stage for moving the plate P in the XY plane, a Z stage for moving the plate P in the Z-axis direction, and a plate P.
, And a stage that changes the angle with respect to the Z-axis to adjust the inclination of the plate P with respect to the XY plane. Stage PS
Movable mirrors 13X and 13Y as reference members having a length longer than the movable range of the stage PS are attached to one end of the upper surface of the laser beam. Each is arranged.

Although the illustration is simplified in FIG. 1, the laser interferometer 14X includes two X-axis laser interferometers for irradiating the movable mirror 13X with a laser beam along the X-axis. One laser interferometer for axis and laser interferometer 14
Based on Y, the X coordinate and the Y coordinate of the stage PS are measured. The rotation angle of the stage PS in the XY plane is measured based on the difference between the measurement values of the two laser interferometers for the X axis. Information on the X coordinate, the Y coordinate, and the rotation angle measured by the laser interferometers 14X and 14Y are supplied to the main control system 15 as stage position information. The main control system 15 outputs the supplied stage position information to the stage drive systems 16X and 16Y while monitoring the stage position information, and controls the positioning operation of the stage PS. Although not shown in FIG. 1, the mask M
The mask stage MS on which the stage 1 is mounted is also provided with a moving mirror and a laser interferometer provided for the stage PS. Is done.

Here, the arrangement of members provided on the stage PS for measuring various types of position information will be described. FIG. 2 is a diagram showing the arrangement of members provided on the stage PS used when measuring various types of position information.
As shown in FIG. 2, the stage PS includes a reflector RF.
0, reflectors RF1 to RF4, and reference marks FM1, F
M2 is provided. Reflector RF0, Reflector RF1
RF4 and fiducial marks FM1 and FM2 are on stage P
S is configured to be freely protruded and immersed with respect to S, and is designed so that the upper surface thereof is substantially flush with the upper surface of the plate P when protruding above the stage PS. Also, by immersing these in the stage PS, the plate P is moved to the stage PS.
It can be placed on top. Reflector RF0, Reflectors RF1-R
The reason why the F4 and the reference marks FM1 and FM2 can be freely projected and retracted is to reduce the size of the stage PS.
That is, if these are formed in portions other than the portion where the plate P is placed, the stage PS is correspondingly enlarged. In addition, what kind of position information is used when the reflector RF0, the reflectors RF1 to RF4, and the reference marks FM1 and FM2 are used will be described as needed below. In FIG. 2, the plate alignment sensor 20 shown in FIG.
The arrangement relation of a to 20d is also illustrated. When the stage PS moves, the plate alignment sensors 20a to 20a
The reflection plate RF0, the reflection plates RF1 to RF4, and the reference marks FM1 and FM2 move with respect to d.

Returning to FIG. 1, the position of the stage PS in the Z-axis direction is determined by an autofocus comprising a light projecting system 17a and a light receiving system 17b disposed above the stage PS and beside the projection optical system PL. It is measured by the mechanism 17. The auto-focus mechanism 17 irradiates the detection light emitted from the light projecting system 17a to a reflecting plate RF0 (see FIG. 2) provided on the stage PS from an oblique direction, and reflects the reflected light by a light receiving system 17b. By receiving the light, the upper surface of the plate P is positioned at a position conjugate with the mask M1 placed on the mask stage MS in the optical axis direction (Z-axis direction) of the projection optical system PL. . Although not shown in FIG. 1, the reflection plate R0 and the reflection plate RF2 are not shown.
There is also provided a measuring device for sequentially irradiating at least two of RF4 through RF4 with detection light from oblique directions to measure the position information of the stage PS in the Z-axis direction and the inclination of the stage PS.

On the other hand, the position information of the mask is measured by mask observation systems 18a and 18b provided above the mask. The mask observation systems 18a and 18b measure the position of the position measurement mark by irradiating the position measurement mark drawn outside the pattern area on the mask with detection light and receiving the reflected light. And outputs the measurement result to the main control system 15. Normally, a pattern formed in the pattern area of the mask and a mark for position measurement have a drawing error, and depending on the position of the mask, it is necessary to consider the influence of distortion of the projection optical system PL. Are arranged near the pattern area.

In this embodiment, four masks M1
To M4, the mask observation system 18a, 18b sets the pattern image formed on each mask on the mask stage MS before transferring the image of the pattern formed on each mask to the plate P. Position information is accurately measured for each mask to be placed. The main control system 15
Based on the measurement results of the mask observation systems 18a and 18b, the mask stage MS holding the mask M1 can be moved to a desired position on the XY plane by servo-controlling a driving unit such as a linear motor (not shown). It is a configuration that can be done. Also, a lens 1 is provided in the illumination optical system.
An alignment system composed of 9a and a photoelectric detector 19b is provided. This alignment system uses the fiducial mark FM
1, a mark for position measurement formed on the mask M using the FM2 is detected by the TTL method.

Further, a photoelectric measuring device is provided on the stage PS. This photoelectric measuring device is a mask stage M
The pattern formed on the mask mounted on the mask stage MS receives an image obtained by irradiating exposure light to a position measurement mark formed on the mask mounted on the mask stage MS. Of the projected image (exposure center). The exposure center measured by the photoelectric measurement device is used when obtaining the baseline amount. FIG. 3 is a cross-sectional view illustrating a configuration of a photoelectric measurement device used when obtaining a baseline amount for the stage PS. As shown in FIG. 3, the photoelectric measurement device includes the reference marks FM1 and FM2, the lens 31, the stop 32, the lens 33, the field stop 34, and the lens 3.
5 and a photoelectric conversion element 36.

The reference marks FM1 and FM2 have slit patterns 30a used for measuring the baseline amount.
And a reference position mark 30b are formed. FIG.
Is a diagram showing an example of a slit pattern 30a and a reference position mark 30b formed on the reference marks FM1 and FM2. Slit pattern 30a and reference position mark 3
Ob is formed, for example, by depositing chromium on a transparent glass substrate. In FIG. 4, a portion where chromium is deposited is hatched. The slit pattern 30a is formed in a shape in which an opening whose longitudinal direction is set in the X-axis direction and an opening whose longitudinal direction is set in the Y-axis direction intersect.

FIG. 5 is an enlarged view of the reference position mark 30b. As shown in FIG. 5, the reference position mark 30b is
U-shaped mark element 37a and U-shaped mark element 3
7b are arranged in the X-axis direction, and U-shaped mark elements 37c and 37d are arranged in the Y-axis direction. Here, the opening 38a of the U-shaped mark element 37a and the U-shaped mark element 37b
The opening 38b of the U-shaped mark element 37c and the opening 38d of the U-shaped mark element 37d are set so as to face in opposite directions. You. Further, the reference position mark 30
b, an L-shaped mark element 39a whose longitudinal direction is set in each of the X-axis direction and the Y-axis direction is arranged adjacent to the U-shaped mark elements 37a and 37c. The element 39b is disposed adjacent to the mark element 37b and the mark element 37c, and the L-shaped mark element 39c
Are disposed adjacent to the mark elements 37b and 37d, and the L-shaped mark element 39d is disposed adjacent to the mark elements 37c and 37d.

Returning to FIG. 3, the slit pattern 30a is
It is used when measuring the center (exposure center) of the projected image of the pattern formed on the mask mounted on the mask stage MS. Therefore, an image of a mark for position measurement formed on the mask mounted on the mask stage MS is projected onto the slit pattern 30a via the projection optical system PL. The light passing through the slit pattern 30a forms an image at the position of the field stop 34 via the lens 31, the stop 32, and the lens 33 in this order. The field stop 34 is provided with reference marks FM1 and FM2 for the lenses 31 and 33.
It is arranged at a position conjugate with. This light passes through an opening formed in the field stop 34, reaches the photoelectric conversion element 36 via the lens 35, and is photoelectrically converted. Since the photoelectric conversion element 36 is disposed at the position of the pupil with respect to the reference marks FM1 and FM2, it outputs a signal indicating the intensity of incident light.

On the other hand, the reference position mark 30b is used when measuring the measurement center of the plate alignment sensors 20a to 20d described later. Therefore, the reference position mark 3
Ob is illuminated with detection light emitted from the plate alignment sensors 20a to 20d. Reference position mark 30
The detection light that has passed through the periphery of b is a lens 31, an aperture 32,
Then, the light enters the field stop 34 via the lens 33 in order, but is blocked by the field stop 34. The plate alignment sensors 20a to 20d transmit the detection light to the reference position mark 30.
Reference position mark 3 using reflected light obtained by irradiating b
0b, the reference position mark 30b
It is not necessary to photoelectrically convert the detection light transmitted through the periphery of the photodetector with the photoelectric conversion element 36 to obtain a signal indicating the light intensity. For this reason, the field stop 34 is used to measure the center (exposure center) of the projected image of the pattern formed on the mask when the slit pattern 30a is used.
When the measurement center of the plate alignment sensors 20a to 20d is measured, the detection light transmitted around the reference position mark 30b is shielded. Incidentally, as shown in FIG. 2, the reference marks FM1 and FM2
The reason why two are formed on the stage PS is to reduce the amount of movement of the stage PS.

Returning to FIG. 1, beside the projection optical system PL,
Further, four off-axis type plate alignment sensors 20a to 20d are arranged. These four plate alignment sensors 20a to 20d form a part of the position measuring device according to the embodiment of the present invention. The plate alignment sensors 20a to 20d measure the position information of the reference position marks 30b formed on the reference marks FM1 and FM2 and the mark formed on the plate P shown in FIG. The reason why the plurality of plate alignment sensors 20a to 20d are provided as shown in FIG. 1 is to reduce the amount of movement of the stage PS and to improve the throughput.

Next, plate alignment sensors 20a to 20a forming a part of the position measuring device according to one embodiment of the present invention.
20d will be described in detail. [First Configuration Example of Plate Alignment Sensors 20a to 20d] FIG. 6 is a view showing plate alignment sensors 20a to 20d which are part of a position measuring device according to an embodiment of the present invention.
It is a figure showing the 1st example of composition of the optical system of d. Since the configurations of the plate alignment sensors 20a to 20d are the same, FIG. 6 shows only the configuration of the plate alignment sensor 20a as a representative. In FIG. 6, a halogen lamp 40 emits light having a wavelength bandwidth of about 400 to 800 nm. The light emitted from the halogen lamp 40 is converted into parallel light by a condenser lens 41, and then is converted into a dichroic filter 4.
2 is incident. The dichroic filter 42 is composed of a plurality of filters configured to freely enter and exit the optical path of the light emitted from the halogen lamp 40. By changing the combination of filters inserted into the optical path, a predetermined Only the light in the wavelength band is selected and transmitted.
For example, of the light emitted from the halogen lamp 40, light in a blue region (wavelength region: about 420 to 530 nm) and light in a red region (wavelength region: about 580 to 730 nm)
Degree), only light in the yellow region, or white light (almost all of the wavelength band of light emitted from the halogen lamp 40) can be transmitted.

The light transmitted through the dichroic filter 42 enters a condenser lens 43 which is set so that one of the focal points is located substantially at the position of the incident end 44a of the optical fiber 44. The optical fiber 44 has one entrance end and four exit ends, and each exit end is a plate alignment sensor 2
0a to 20d are respectively guided inside. The halogen lamp 40, the condenser lens 41, the dichroic filter 42, and the condenser lens 43 are provided outside the chamber of the exposure apparatus in order to avoid thermal effects, and light transmitted through the dichroic filter 42 is It is configured to guide each of the alignment sensors 20a to 20d.

The light emitted from one emission end 44b of the optical fiber 44 is used as the detection light IL1. The detection light IL1 illuminates an index plate 46 on which an index mark 47 of a predetermined shape is formed via a condenser lens 45. Here, the configuration of the index plate 46 will be described. FIG. 7 is a diagram illustrating an example of the shape of the index mark 47 formed on the index plate 46. The index mark 47 includes a first light-shielding portion 47a that shapes the incident detection light IL1 into a rectangular shape, and a second light-shielding portion 47b that shields a part of the rectangular detection light IL1 into an annular shape having four sides. Are formed. The light-shielding portion 47a is formed to define an irradiation area when the detection light IL1 is irradiated on the mark formed on the plate P and the reference position mark 30b formed on the reference marks FM1 and FM2. The second light-shielding portion 47b is formed to determine a reference position when measuring position information of a mark to be measured. That is, the index mark 47 serves both as a field stop and a mark that determines a reference position used when measuring the position information of the mark.

FIG. 8 is an enlarged view of the second light shielding portion 47b. As shown in FIG. 8, the second light-shielding portion 47b is formed in an annular shape having four sides, and cross-shaped light-shielding portions q1 to q4 are formed at four corners. The light shielding portions q1 to q4 are provided by the plate alignment sensor 20.
It is used when adjusting the arrangement of the index plates 46 provided in a to 20d. Adjustment of the arrangement of the index plate 46 is performed by the second light shielding portion 4.
The image 7b is picked up by the image pickup devices 53 and 54 (see FIG. 6), which will be described later, and is observed while observing the position of the image in a monitor (not shown). At this time, a linear test pattern is displayed in the scanning line direction of the monitor or in a direction perpendicular to the scanning line, and adjustment is performed so that the test pattern and each side of the second light shielding portion 47b are parallel. I do.

Normally, since the test pattern is narrower than the width of each side of the second light-shielding portion 47b, variations may occur when each side of the second light-shielding portion 47b is directly parallel to the test pattern. . Therefore, cross-shaped light shielding portions q1 to q4 shown in FIG. 8 are provided at the four corners of the second light shielding portion 47b.
The test pattern displayed on the monitor is adjusted so as to pass through at least two adjacent cross-shaped light-shielding portions q1 to q4. Since the cross-shaped light-shielding portions q1 to q4 are set to have a width of about one third of each side of the second light-shielding portion 47b, the accuracy of the adjustment is improved and the adjustment can be easily performed. The index plate 46 on which the index mark 47 shown in FIG. 7 is formed is an image forming surface FC as an image forming position of the detection light IL.
It is arranged at a position that is optically conjugate with. The mark formed on the plate P and the reference mark FM
Since the reference position marks 30b formed on the FM1 and FM2 are arranged, these marks are irradiated with the detection light including the image of the second light shielding portion 47b. In the following description, the image of the second light-shielding portion 47b is referred to as an image of an index mark for simplification of the description.

As shown in FIG. 6, the plate alignment sensors 20a to 20d of the present embodiment are located at positions in the irradiation optical system which are optically conjugate with the image forming position of the detection light IL1. Has been arranged. Referring to FIG. 21, a conventional field stop 102 is disposed at a position where the index plate 46 is disposed. That is, in the present embodiment, instead of the conventional field stop 102, the index mark 47 including the first light shield 47a serving as the field stop 102 and the second light shield 47b serving as the conventional index mark is formed. The indicated index plate 46 is arranged. Therefore, the conventional index plate 110 is provided on the light receiving side, and the image of the mark 107 is
A relay optical system for forming an image on 0 and the image pickup surface of the image pickup device 113 is not required, so that the position information of the mark can be measured with low cost, small size, and high measurement accuracy.

Returning to FIG. 6, the detection light IL1 that has passed through the index plate 46 is incident on a half mirror 49 that branches light transmission and light reception via a relay lens 48. The detection light IL1 reflected by the half mirror 49 is imaged on the image plane FC via the objective lens 50. The optical fiber 44, the condenser lens 45, the index plate 46, the relay lens 48 described above,
The half mirror 49 and the objective lens 50 form an irradiation optical system. Marks or reference marks F formed on the plate P
When M1 and FM2 are arranged on the imaging plane FC,
The reflected light is reflected by the objective lens 50, the half mirror 49, and the second
The beam is split in two directions in the beam splitter 52 via the objective lens 51 in order, and one of the split reflected lights is CC
Forming an image on an imaging surface of a low-magnification imaging device 53 including D and the like;
The other reflected light is a high-magnification image sensor 54 having a CCD or the like.
Is formed on the imaging surface of. When measuring the position information of the mark formed on the plate P and the reference marks FM1 and FM2, first, rough position information of the mark is obtained by using the low-magnification imaging device 53, and then the high-magnification imaging device 54 is obtained. In general, position information is obtained with high accuracy by using. The imaging devices 53 and 54 are plate alignment sensors 20a-2
Each is provided to measure the 0d measurement visual field at different magnifications. The objective lens 50, the half mirror 49, the second objective lens 51, the beam splitter 52, and the imaging devices 53 and 54 constitute a light receiving optical system.

The image pickup device 53 and the image pickup device 54 sequentially convert the optical images formed on the respective image pickup surfaces into image signals while scanning them in a predetermined scanning direction, and output the image signals to the main control system 15. The main control system 15 includes an image sensor 53 or an image sensor 54
Image processing is performed on the image signal output from the image sensor 53, for example, the center position of the index mark from the center position of the imaging surface of the imaging device 53 or the center position of the imaging surface of the imaging device 54, and the shift amount of the center position of the mark are obtained. Laser interferometer 14X, 14Y
From the main control system 15, the X-axis direction of the stage PS and Y
Since the position of the axis method and the stage position information indicating the amount of rotation of the stage PS are always input, the main control system 15
Based on the stage position information and the amount of deviation of the center position of the index mark and the center position of the mark from the center position of the imaging surface of the imaging device 53 or the center position of the imaging surface of the imaging device 54,
Find the position information of the mark being measured.

The first configuration example of the exposure apparatus according to one embodiment of the present invention and the plate alignment sensors 20a to 20d forming a part of the position measuring apparatus according to one embodiment of the present invention have been described. The operation of the position measuring device and the exposure device according to one embodiment of the present invention will be described. FIG. 9 is a flowchart showing a schematic operation of the exposure apparatus according to the embodiment of the present invention when measuring the baseline amount. In the exposure apparatus of this embodiment, first, the mask M1 is placed on the mask holder MS, and the mask observation system 18 shown in FIG.
The detection light is applied to the position measurement mark drawn outside the pattern area on the mask M1 in steps a and b, and the reflected light is received to measure the position information of the position measurement mark. The measured position information is output to the main control system 15, and the main control system 15 adjusts the position of the mask M1 by finely moving the mask stage MS based on the position information, and arranges the mask M1 at a predetermined position. Then, the position information at that time (for example, position information indicating the center position of the mask M1) is stored (step S10). Further, the reflection plate RF0, the reflection plates RF1 to RF4, and the reference marks FM1 and FM2 provided on the stage PS are made to protrude with respect to the stage PS, and the upper surface of these members is placed on the stage PS. Is set to be substantially flush with the upper surface of the plate P in the above case.

Next, the main control system 15 moves the stage PS to position the reflector RF0 (see FIG. 2) at the projection center of the projection optical system PL, and the autofocus mechanism 17 moves the stage PS in the Z-axis direction. The position information is measured (step S12). When detecting the position information of the stage PS in the Z-axis direction, the light projecting system 17a irradiates detection light onto the reflector RF0 from an oblique direction of the reflector RF0, and the reflected light is received by the light receiving system 17b. The main control system 15 adjusts the position of the stage PS in the Z-axis direction based on the light reception result output from the light receiving system 17b, thereby mounting the reflection surface RF0 (corresponding to the upper surface of the plate P) on the mask stage MS. It is positioned at a position conjugate with the placed mask M1.

When the above processing is completed, a portion of the mask M1 mounted on the mask stage MS where the mark for position measurement is formed is irradiated with exposure light, and a photoelectric measurement device provided on the stage PS (FIG. 3) is performed to measure the center (exposure center) of the projected image of the pattern formed on the mask mounted on the mask stage MS (step S14). In measuring the exposure center, the main control system 15 moves the stage PS to dispose the reference mark FM1 near the exposure center, and then irradiates the exposure light to the position measurement mark formed on the mask M1 with the exposure light. The image of the mark for position measurement is transferred to the reference mark F via the projection optical system PL.
Irradiated on M1. The light that has passed through the slit pattern 30a (see FIG. 4) formed in the reference mark FM1 enters the field stop 34 through the lens 31, the stop 32, and the lens 33 in order, passes through the field stop 34, and further passes through the lens. The light reaches the photoelectric conversion element 36 via 35 and is subjected to photoelectric conversion.

The signal output from the photoelectric conversion element 36 is
This is a signal indicating the intensity of light incident on the photoelectric conversion element 36, and this signal is output to the main control system 15. Main control system 1
Reference numeral 5 denotes a state in which a signal is output from the photoelectric conversion element 36, the stage is moved via the stage driving systems 16X and 16Y, and the stage position information output from the laser interferometers 14X and 14Y and the stage position information are output from the photoelectric conversion element 36. Obtain the relationship with the output signal. Since the position measurement mark formed on the mask M1 has a substantially cross shape, the mark is output from the photoelectric conversion element 36 when the position where the image of the mark is irradiated coincides with the position of the slit pattern 30a. Signal is maximum. Therefore, when the signal output from the photoelectric conversion element 36 is maximized, the laser interferometer 14X, 1
The exposure center is measured by obtaining the stage position information output from 4Y. The measurement of the exposure center may be performed using either the reference mark FM1 or the reference mark FM2.

Next, each plate alignment sensor 20
Measurement of the measurement center of a to 20d is performed (Step S1)
6). In this measurement, the main control system 15 performs control to sequentially measure the position information of the reference mark FM1 shown in FIG. 2 by the plate alignment sensors 20a and 20d.
Control for sequentially measuring the position information of the reference mark FM2 by the plate alignment sensors 20b and 20c is performed. Thus, the reference mark FM is placed at a different position on the stage PS.
By arranging 1 and FM2, the amount of movement of the stage PS can be reduced. As a result, the size of the stage PS can be reduced.

Now, the plate alignment sensor 20a
The method of measuring the measurement center will be described by taking as an example the case where the measurement center is measured. First, the main control system 15 moves the stage via the stage driving systems 16X and 16Y, and the reference mark 20a is arranged immediately below the plate alignment sensor 20a. Next, light having a wavelength bandwidth of about 400 to 800 nm is emitted from the halogen lamp 40 shown in FIG. This light passes through a lens 41, a dichroic filter 42, and a condenser lens 43 in this order and enters an incident end 44.
a enters the optical fiber 44. The light incident from the incident end 44a is guided into the plate alignment sensor 20a by the optical fiber 44. 1 of optical fiber 44
Light emitted from the two emission ends 44b is used as detection light IL1. The detection light IL1 is transmitted through the condenser lens 45 to the index plate 4 on which the index mark 47 having a predetermined shape is formed.
Illuminate 6. When the detection light IL1 irradiates the index plate 46, the transmitted detection light IL1 is shaped into a rectangular shape and includes an image of the index mark.

The detection light IL1 transmitted through the index plate 46 passes through the relay lens 48, is reflected by the half mirror 49, and is focused by the objective lens 50. Therefore, the image of the index mark is formed on the image forming plane FC. Now, since the reference mark FM1 is arranged on the imaging plane FC, the reference position mark 30 is detected by the detection light including the image of the index mark.
b is illuminated. Here, referring to FIG. 3, the detection light I
Even if L1 illuminates the reference position mark 30b, the field stop 34
Therefore, the detection light IL1 is not received by the photoelectric conversion element 36. Light (reflected light or diffracted light) obtained by irradiating the reference position mark 30b with the detection light IL1
Reaches a beam splitter 52 via an objective lens 50, a half mirror 49, and a second objective lens 51, and is branched in two directions. Each of the branched lights forms an image on each of the imaging surface of the imaging device 53 and the imaging surface of the imaging device 54, and is converted into an image signal.

FIG. 10 is a diagram showing an example of the image of the reference position mark 30b and the image of the index mark formed on the imaging surface of the high-magnification imaging element 54. In FIG. 10, FP indicates an imaging surface of the imaging element 54. FIG. 10 shows the reference position mark 3 in the imaging plane FP for easy understanding.
This shows a state in which the image Im2 of the index mark is formed at the center position of the image Im1 of 0b and is formed. Since the reference position mark 30b is formed of chrome, the image Im1 of the reference position mark 30b is an image brighter than the surroundings, but the image Im2 of the index mark is the second light shielding portion 4 shown in FIG.
Since the detection light IL1 is shielded by 7b, the image is darker than the surroundings.

In FIG. 10, SC1 indicates a detection area whose longitudinal direction is set in the X-axis direction, and SC2 indicates a detection area whose longitudinal direction is set in the Y-axis direction. Main control system 15
Is formed on the imaging plane FP based on a change in the signal intensity in the X-axis direction in the detection area SC1 set in the imaging area FP of the imaging element 54 and a change in the signal intensity in the Y-axis direction in the detection area SC2. Of the center position of the image Im1 of the reference position mark 30b with respect to the center position of the image Im2 of the index mark formed on the imaging surface FP from the interval between the edge positions in the X-axis direction and the Y-axis direction. Find the shift amount.

Each plate alignment sensor 20a-2
When the measurement of the measurement center of 0d is completed, the main control system 15
From the exposure center obtained in step S14 and the measurement centers of the plate alignment sensors 20a to 20d obtained in step S16, each plate alignment sensor 20a
The base line amount for 〜20d is calculated (step S18). After the baseline amount is calculated, the main control system 15 determines whether there is another mask (step S20). The determination result in this step is “NO” when the exposure processing is performed using a single mask,
When performing exposure processing using a plurality of masks, “YE
S ". If the determination result in step S20 is “N
In the case of "O", the process ends, and in the case of "YES",
The mask mounted on the mask stage MS is exchanged (Step S22). For example, the mask stage M
When the mask M1 is placed on S, the mask M2
Will be replaced.

When the mask replacement is completed, the detection light is applied to the position measurement mark drawn outside the pattern area on the mask M2 mounted on the mask stage MS by the mask observation systems 18a and 18b shown in FIG. By irradiating and receiving the reflected light, the position information of the position measurement mark is measured (step S24). The measured position information is output to the main control system 15. The main control system 15 calculates and stores the difference between the position information and the position information stored in step S10 (step S26). Next, the main control system 15 determines whether or not there is another mask (step S2).
8). If the result of this determination is “NO”, the measurement processing of the baseline amount ends. On the other hand, if the result of the determination in step S28 is "YES", the process proceeds to step S28.
Returning to step 22, the mask is replaced and the positional information of the mask placed on the mask stage MS is measured, and step S1 is performed.
Processing for obtaining a difference from the position information stored as 0 is performed.

As described above, in the present embodiment, when the exposure processing is performed using a plurality of masks, the baseline amount is obtained only for the mask initially placed on the mask stage MS. is there. The measurement of the baseline amount was not performed for the second and subsequent masks, but the difference with respect to the positional information of the mask placed first on the mask stage MS was obtained, and the measured baseline amount was corrected with this difference. Use the baseline amount.

The method of measuring the baseline amount has been described above. Next, the operation when the plate P is mounted on the stage PS and the position information of the plate P is measured will be described. In the following description, the position information of the mark formed on the plate P is measured by using the plate alignment sensors 20a to 20d. In the present embodiment, the mark on the plate P is replaced by the plate alignment sensors 20a to 20d. In the following, a description will be given by taking as an example a case in which it is formed at a position corresponding to. FIG. 11 is a schematic diagram showing an arrangement relationship of marks formed on the plate P. FIG.
As shown in FIG. 5, at the four corners of the plate P and at positions corresponding to the plate alignment sensors 20a to 20d, the reference position marks 30b (see FIG. 5) formed on the reference marks FM1 and FM2 have the same shape. Mark AM
1 to AM4 are formed. The areas SA1 to SA4 in FIG. 11 are areas where the images of the patterns formed on the masks M1 to M4 are respectively transferred. Note that FIG.
In the figure, the sizes of the marks AM1 to AM4 are exaggerated.

FIG. 12 shows the plate alignment sensor 2
Mark A formed on plate P using 0a to 20d
It is a flowchart which shows the operation | movement at the time of measuring the position information of M1-AM4. Before the plate P is transferred onto the stage PS, pre-alignment for mechanically adjusting the rotation and the like of the plate P is performed in advance (Step S30), and then the pre-aligned plate P is transferred onto the plate stage PS. Is placed. In addition, the reflection plate RF0,
Reflectors RF1 to RF4 and reference marks FM1 and FM2
Is immersed in the stage PS before the plate P is placed on the plate stage PS.

Next, the plate alignment sensor 20a
Whether the position information in the Y-axis direction of the mark AM1 formed on the plate P can be measured simultaneously with the position information in the Y-axis direction of the mark AM2 formed on the plate P using the plate alignment sensor 20b. Is determined (step S32). This step S32 is provided in order to cope with a case where the interval between the marks AM1 and AM2 formed on the plate P is different from the interval between the plate alignment sensors 20a and 20b. It is. In the following description and FIG. 12, the position information of the mark AM1 in the X-axis direction and the Y-axis direction is represented by P1x and P1y, respectively, and the position information of the mark AM2 in the X-axis direction and the Y-axis direction is represented by P2x and P2y, respectively. Represents the mark AM3
Are represented as P3x and P3y in the X-axis direction and the Y-axis direction.

The result of the determination in step S32 is "YE
S ”, the position information P of the mark AM1 in the X-axis direction
1x and y-axis position information P1y and mark AM
A process of simultaneously measuring the position information P2y in the Y-axis direction at a low magnification is performed (step S34). In this process,
The main control system 15 (see FIG. 1) uses the image signal output from the low-magnification image sensor 53 shown in FIG.
1x, P1y, and P2y are obtained. Next, step S34
A process of calculating the shift amount and the rotation amount of the plate P is performed using the position information P1x, P1y, and P2y measured in (step S36). Next, in order to prevent the rotation amount of the plate P from affecting the next measurement process, it is determined whether the rotation amount of the plate P is within a predetermined allowable range (step S38). .

When the result of the determination in step S38 is "N
In the case of "O", the stage PS is rotated so that the rotation amount of the plate P falls within the allowable value in step S40, and the process proceeds to step S42. On the other hand, if the decision result in the step S38 is "YES", the process directly proceeds to the step S42.
Proceed to. In step S42, the mark AM formed on the plate P using the plate alignment sensor 20a
1. A mark AM formed on the plate P using the position information in the Y-axis direction and the plate alignment sensor 20b.
2, a process of simultaneously measuring the position information in the X-axis direction and the position information in the Y-axis direction at a high magnification. In this process, the main control system 15 uses the image signal output from the high-magnification image sensor 54 shown in FIG. 6 to generate the position information P1y, P2x,
Find P2y. Then, a process of calculating the shift amount and the rotation amount using the position information P1y, P2x, P2y measured in step S42 is performed (step S44). Next, it is determined whether or not the rotation amount obtained in step S44 is within an allowable range (step S46). If the determination result is “NO”, the stage is rotated to such an extent that the rotation amount of the plate P falls within the allowable range (step S4).
8), the process returns to step S42. On the other hand, step S
If the determination result at 46 is “YES”, a process of measuring the mark AM3 formed on the plate P at a high magnification using the plate alignment sensor 20c is performed (step S50).

On the other hand, if the result of the determination in step S32 is "N
If "O", the two plate alignment sensors 20a and 20b are measured as measured in step S34.
, The position information of the marks AM1 and MA2 is not measured at the same time.
The position information P1x in the X-axis direction and the position information P1y in the Y-axis direction of the mark AM1 are measured at a low magnification using a (step S52). Next, the plate alignment sensor 20
The position information of the mark AM2 in the Y-axis direction is measured at a low magnification using b (step S54). Then, step S5
2. Position information P1x and P1y measured in step 2 and step S
A process of calculating the shift amount and the rotation amount of the plate P using the position information P2y measured at 54 is performed (Step S56). Next, in order to prevent the rotation amount of the plate P from affecting the next measurement process, it is determined whether the rotation amount of the plate P is within a predetermined allowable range (step S58). .

When the result of the determination in step S58 is "N
In the case of “O”, the stage PS is rotated so that the rotation amount of the plate P falls within the allowable value in step S60, and the process proceeds to step S62. On the other hand, if the judgment result in the step S58 is "YES", the step S62 is performed as it is.
Proceed to. In step S62, the mark AM formed on the plate P using the plate alignment sensor 20a
A process of measuring the position information P1y in the Y-axis direction at a high magnification is performed. Next, the plate alignment sensor 20b
Is used to measure the position information P2x in the X-axis direction and the position information P2y in the Y-axis direction of the mark AM2 formed on the plate P at a high magnification (step S64). Then, it is determined whether or not the rotation amount obtained by performing the high-magnification measurement is within an allowable range (step S66). If the determination result is “NO”, the rotation amount of the plate P is allowable. Rotate the stage so that it is within the range (step S
68), the process returns to step S62. On the other hand, if the result of the determination in step S66 is “YES”, a process of measuring the mark AM3 formed on the plate P at a high magnification using the plate alignment sensor 20c is performed (step S50).

Through the above processing, the processing for measuring the position information of the marks AM1 to AM3 formed on the plate P using the plate alignment sensors 20a to 20c is completed. The four pieces of position information obtained by the above measurement, that is, the position information P1y of the mark AM1 in the Y-axis direction, the position information P2x of the mark AM2 in the X-axis direction, the position information P2y of the mark AM2 in the y-axis direction, and the position information of the mark AM3 Statistical calculation processing called so-called enhanced global alignment (EGA) measurement is performed using the position information P3x in the X-axis direction to calculate the array coordinates of the exposure areas SA1 to SA4. Next, the main control system 15 aligns the exposure area SA1 of the plate P with the exposure center based on the array coordinates of the exposure areas SA1 to SA4 obtained by the EGA measurement and the base line amount obtained in advance. Then, exposure light from the illumination optical system is irradiated onto the mask M1, and an image of a pattern formed on the mask M1 is transferred to the exposure area SA1 of the plate P via the projection optical system PL.

Next, the main control system 15 controls the mask stage M
The mask M1 mounted on S is replaced with a mask M2, and the stage PS is driven by stepping to align the plate P exposure area SA2 with the exposure center, thereby projecting the image of the pattern formed on the mask M2. Optical system PL
Is transferred to the exposure area SA2 via the. Hereinafter, similarly, the same processing is performed on the mask M3 and the mask M4, and all the exposure areas SA1 to SA4 set on the plate P are set.
Is exposed. Thus, a series of operations of the exposure processing ends.

The operation of the position measuring device and the exposure device according to one embodiment of the present invention has been described above. In the above description, the marks AM1 to AM4 formed on the plate P are described.
When forming the position information of the reference position marks 30b formed on the reference marks FM1 and FM2, as shown in FIG. 10, the center position of the image Im1 of the mark formed on the imaging surfaces of the imaging devices 53 and 54 and The position information of the reference position mark 30b formed on the marks AM1 to AM4 and the reference marks FM1 and FM2 is calculated by obtaining the center position of the image Im2 of the index mark and obtaining the relative shift amount.

The image of the index mark irradiated on the marks AM1 to AM4 formed on the plate P is obtained by shielding the detection light IL1 transmitted through the condenser lens 45 with the second light shielding portion 47b shown in FIG. It is formed. When the image of the index mark is applied to the marks AM1 to AM4, the mark is slightly diffracted according to the surface state of the stage PS when it passes through the plate and reaches the surface of the stage PS. The diffracted light generated on the surface of the stage PS slightly brightens the image of the index mark, and the contrast of the image Im2 of the index mark formed on the imaging surfaces of the imaging elements 53 and 54 decreases. When the contrast of the index mark image Im2 decreases, a measurement error occurs when detecting the center position of the index mark image Im2, or in the worst case, the index mark image Im2
It is possible that the center position of No. 2 cannot be detected. The shape of the mark used in the LSA type position measuring device is formed by arranging rectangular dots, and when the image Im2 of the index mark and the image of the mark are captured by the image sensor, the position information of the mark is detected. May not be possible.

In order to solve this problem, it is preferable that the center position of the index mark image Im2 with respect to the imaging surfaces of the imaging elements 53 and 54 is measured and obtained in advance. And
When measuring marks AM1 to AM4, mark A
It is preferable to measure only the position information of the images M1 to AM4 and obtain the position information of the marks AM1 to AM4 from the amount of deviation between the measurement result and the position information of the image Im2 of the index mark measured in advance. is there. For this reason, between the steps S30 and S32 shown in FIG.
A process is performed in which the center position of the index mark image Im2 with respect to the imaging surface 54 is obtained in advance.

FIG. 13 shows the plate alignment sensor 2
It is a flowchart which shows the process which calculates | requires the center position of the image Im2 of the index mark with respect to the imaging surface of the imaging elements 53 and 54 in 0a-20d. When the pre-alignment in step S30 is completed, the main control system 15 moves the stage PS to move the reflection plate RF1 to the plate alignment sensor 20a.
(Step S31a). Reflector RF1
Is completed, the main control system 15 causes the image Im2 of the index mark formed on the imaging surfaces of the imaging devices 53 and 54 to illuminate the reflection plate RF1 with the detection light IL1 from the plate alignment sensor 20a with respect to the imaging surface. The center position is measured and stored (step S31b). Next, the main control system 1
5 moves the stage PS and arranges the reflection plate RF1 at the position of the plate alignment sensor 20d (step S31c).
The image Im2 of the index mark formed on the imaging surfaces of the imaging elements 53 and 54 when the detection light IL1 is applied to the reflection plate RF1.
Is measured and stored with respect to the imaging plane (step S31d).

Next, the main control system 15 moves the stage PS to dispose the reflection plate RF3 at the position of the plate alignment sensor 20c (step S31e). Here, the reason for using the reflection plate RF3 is to reduce the amount of movement of the stage PS to prevent a decrease in throughput. When the arrangement of the reflection plate RF3 is completed, the main control system 15
Is the reflection plate RF3 from the plate alignment sensor 20c.
The center position of the image Im2 of the index mark formed on the imaging surfaces of the imaging devices 53 and 54 when the detection light IL1 is irradiated on the imaging surface is measured and stored (step S31).
f). Finally, the main control system 15 moves the stage PS so that the reflection plate RF3 is moved to the plate alignment sensor 20b.
(Step S31g), and the detection light IL1 is transmitted from the plate alignment sensor 20b to the reflection plate RF3.
The center position of the image Im2 of the index mark formed on the imaging surfaces of the imaging elements 53 and 54 when the image is irradiated with respect to the imaging surface is measured and stored (step S31h). By the above-described processing, the center position of the image of the index mark with respect to the imaging surfaces of the imaging elements 53 and 54 is measured by each of the plate alignment sensors 20a to 20d. Then, when measuring the position information of the marks AM1 to AM3 formed on the plate P according to the flow shown in FIG. 12 (for example, steps S34 and S34).
42), the center position of the image Im1 of the mark formed on the imaging surfaces of the imaging elements 53 and 54 is determined, and the process proceeds to step S31a.
To the index mark I obtained in advance by performing the processes of S31 to S31h.
The position information of the marks AM1 to AM3 is measured from the amount of deviation of the center position of m2.

[Plate alignment sensors 20a-2
Second Example of Configuration of Od] Next, the plate alignment sensor 2 forming a part of the position measuring device according to the embodiment of the present invention
A second configuration example of the optical systems 0a to 20d will be described in detail. FIG. 14 shows plate alignment sensors 20a-2 forming a part of a position measuring device according to an embodiment of the present invention.
FIG. 7 is a diagram illustrating a second configuration example of the optical system 0d, and the same members as those in the first configuration example illustrated in FIG. 6 are denoted by the same reference numerals. Since the configuration of each of the plate alignment sensors 20a to 20d is the same, FIG. 14 shows only the configuration of the plate alignment sensor 20a as a representative. The illustration of the halogen lamp 40, the condenser lens 41, the dichroic filter 42, the condenser lens 43, and the optical fiber 44 shown in FIG. 6 is omitted.

The plate alignment sensor 20a shown in FIG. 14 is replaced with the plate alignment sensor 2 shown in FIG.
0b is different from the index plate 4 provided in the irradiation optical system.
A first correction optical system 60 composed of two direct-view prisms 60a and 60b as an irradiation-side adjustment member is disposed between the relay lens 6 and the relay lens 48. Two direct-view prisms 61a and 61b as light-receiving-side adjusting members between the beam splitter 52 and the beam splitter 52
Is that a second correction optical system 61 composed of As described above, the plate alignment sensors 20a-2a-2
0d is 400 to 8 emitted from the halogen lamp 40
Detection light IL that detects light having a wide wavelength bandwidth of about 00 nm
Since it is used as 1, chromatic aberration occurs in the irradiation optical system and the light receiving optical system, which affects measurement accuracy. The first correction optical system 60 is provided to correct chromatic aberration generated in the irradiation optical system, and the second correction optical system 61 is provided to correct chromatic aberration generated in the light receiving optical system.

The direct-view prisms 60a and 60b and the direct-view prisms 61a and 61b have, for example, a configuration in which two types of prisms having the same refractive index for a certain wavelength in the wavelength band of the detection light IL1 but different Abbe numbers are combined. An Amichi-type direct-view type spectral prism is used. Here, the direct-view prisms 60a, 60b or the direct-view prisms 61a, 61
The principle by which chromatic aberration in the irradiation optical system or chromatic aberration in the light receiving optical system can be corrected using 1b will be described.

FIG. 15 is a diagram for explaining the principle that chromatic aberration can be corrected using the direct-view prisms 60a and 60b or the direct-view prisms 61a and 61b.
Is a direct-view prism 60a, 60b or a direct-view prism 61
It is a perspective view of 61a, 61b, (b) is the code | symbol A in (a).
FIG. 2 is a view as seen from the direction indicated by 1, and FIG. 2C is a view as viewed from the direction indicated by A2 in FIG. In FIG. 15A, a circle denoted by reference numeral C1 represents a virtual plane perpendicular to the optical axis on the incident side of the direct-view prism 60a or the direct-view prism 61a, and a circle denoted by reference C2 is:
A virtual plane perpendicular to the optical axis between the direct-viewing prism 60a and the direct-viewing prism 60b, or between the direct-viewing prism 61a and the direct-viewing prism 61b, and a circle denoted by reference symbol C3,
It represents a virtual plane perpendicular to the optical axis on the exit side of the direct-view prism 60b or the direct-view prism 61b. For convenience, an xy orthogonal coordinate system is set for each of the planes C1 to C3.

It is assumed that chromatic aberration occurs due to the objective lens 50 in FIG. 14, and for example, a spatial separation occurs between the wavelength λ ₁ component and the wavelength λ ₂ component of the point image on the plane C1. FIG.
In the plane C1 of (a), the point indicated by symbol L10 denotes the wavelength lambda ₁ component of the point image, the point indicated by symbol L20 denotes the wavelength lambda ₂ component of the point image. When each wavelength component of the point image passes through the direct-view prism 60a or the direct-view prism 61a, y
The chromatic aberration in the axial direction is corrected, and the point image L1 on the plane C2 is corrected.
0 is a point image L11 on x, and point image L20 is a point image L21 on x. Further, when each point image passes through the direct-view prism 60b or the direct-view prism 61b, the chromatic aberration in the x-axis direction is corrected, and the point images L11 and L21 on the plane C3.
Is the point image L located on the optical axis, that is, the origin of the xy rectangular coordinate system.
12, L22.

In FIG. 15, although the correction direction of the direct-view prism 60a and the correction direction of the direct-view prism 60b are orthogonal, or the correction direction of the direct-view prism 61a is orthogonal to the correction direction of the direct-view prism 61b. The direct-view prisms 60a and 60b are configured to be rotatable in a plane perpendicular to the optical axis of the irradiation optical system, and the direct-view prisms 61a and 61b are configured to be rotatable in a plane perpendicular to the optical axis of the light-receiving optical system. By rotating the direct-view prism 60a and the direct-view prism 60b relatively, the correction amount of the chromatic aberration in the x-axis direction and the y-axis direction in the irradiation optical system can be changed. , The amount of correction of chromatic aberration in the x-axis direction and the y-axis direction in the light receiving optical system can be changed. Therefore,
It is possible to arbitrarily adjust the correction direction and the correction amount of the chromatic aberration without the irradiation optical system and the light receiving optical system.

Next, the plate alignment sensor 20a
A method of adjusting the chromatic aberration correction direction and the correction amount in each of 20d will be described. FIG. 16 is a flowchart illustrating a procedure of a method of adjusting the direction and amount of correction of chromatic aberration in the plate alignment sensor 20a. Although FIG. 16 shows a method of adjusting the correction amount of the chromatic aberration of the plate alignment sensor 20a, the other plate alignment sensors 20b to 20d can be adjusted by the same method.

First, the main control system 15 moves the stage PS so that the reference mark FM1 formed on the stage PS
Is arranged at the position of the plate alignment sensor 20a (step S70). At this time, the reference mark FM1 is projected from the stage PS. Next, although not shown in FIG. 14, the wavelength region of the detection light IL1 is set by the dichroic filter 42 (Step S).
72). For example, it is set so that only light in the red region is transmitted. By performing this setting, the wavelength region of the detection light IL1 is set. Next, the detection light IL1 in which the wavelength region is set is irradiated on the reference position mark 30b formed on the reference mark FM1, and the position information of the reference position mark 30b is measured (Step S74). Here, the reference position mark 30b is used as a first reference mark in the present invention.

Now, assuming that chromatic aberration is caused by the objective lens 50, the position information of the reference position mark 30b is measured with a shift of δ ₁ from the originally measured position. In step S74, since the position information of the reference position mark 30b is measured via the light receiving optical system, the chromatic aberration generated in the irradiation optical system does not affect the measurement of the position information of the reference position mark 30b. In the present embodiment, the index plate 46 is provided in the irradiation optical system. However, when the chromatic aberration of the light receiving optical system is adjusted, the index plate 4 is used.
Since the position information of the reference position mark 30b is not obtained based on the relative position with respect to the index 6, the index plate 46 may be temporarily removed from the optical path of the irradiation optical system.

Next, it is determined whether or not there is another wavelength region that can be set by the dichroic filter 42 (step S76). If there is another wavelength range ("YES")
Is returned to step S72, the wavelength region of the detection light IL1 is set to another wavelength region (for example, a blue region), and
In step S74, the position information of the reference position mark 30b is measured. On the other hand, if it is determined in step S76 that there is no other wavelength region ("NO"), the detection light I of each wavelength region set in step S72 is determined.
Based on the measurement result (deviation amount δ ₁ etc.) obtained by irradiating L1, the rotation amount of the direct-view prisms 61a and 61b constituting the second correction optical system 61 arranged in the light receiving optical system is adjusted and the light receiving optical system is adjusted. The chromatic aberration generated in the system is corrected (Step S78).

The chromatic aberration of the light receiving optical system is corrected by the above procedure. Next, the main control system 15 moves the stage PS, and arranges the reflector RF1 formed on the stage PS at the position of the plate alignment sensor 20a (step S80). Next, the wavelength region of the detection light IL1 is set by the dichroic filter 42 (step S82). For example, it is set so that only light in the red region is transmitted.
By performing this setting, the wavelength region of the detection light IL1 is set. Then, position information of an image obtained by reflecting the image of the index mark in the set wavelength region of the detection light IL1 with the reflection plate RF1 is measured (step S84).
Here, the second of the index marks 47 formed on the index plate 46 is
The light shielding portion 47b is used as a second reference mark in the present invention. In this measurement, since the chromatic aberration of the light receiving optical system has already been corrected, if the position information of the image of the index mark is measured at a position shifted from the position where it should be originally measured, the irradiation optical system This is due to the resulting chromatic aberration.

Next, it is determined whether or not there is another wavelength region that can be set by the dichroic filter 42 (step S86). If there is another wavelength range ("YES")
Is returned to step S82, the wavelength region of the detection light IL1 is set to another wavelength region (for example, a blue region), and
In step S84, position information of the image of the index mark is measured. On the other hand, when it is determined in step S86 that there is no other wavelength region (in the case of “NO”), based on the measurement result obtained by irradiating the detection light IL1 of each wavelength region set in step S82. Direct-view prism 60 forming first correction optical system 61 disposed in irradiation optical system
The chromatic aberration generated in the irradiation optical system is corrected by adjusting the rotation amounts of a and 60b (step S88).

With the above procedure, the chromatic aberration of the irradiation optical system is corrected. In this embodiment, since the index plate 46 is arranged in the irradiation optical system of each plate alignment sensor 20a, the index plate 46 is used in the above description.
The second light shielding portion 47b of the index mark 47 formed on the second
Used as a reference mark. However, the second fiducial mark does not use the second light-shielding portion 47b formed on the index plate 46 that is permanently provided in the plate alignment sensor 20a, but uses a mark of a predetermined shape that is removably inserted into the irradiation optical system. May be used. The flowchart shown in FIG. 16 shows a procedure for correcting chromatic aberration of only the plate alignment sensor 20a.
When the chromatic aberration is corrected for all of the plate alignment sensors 20a to 20d, the chromatic aberration of all the light receiving optical systems of the plate alignment sensors 20a to 20d is corrected in order, and then the plate alignment sensors 20a to 20d are corrected.
d It is preferable to sequentially correct the chromatic aberrations of all the irradiation optical systems from the viewpoint of shortening the adjustment time because the movement amount of the stage PS can be reduced.

Next, a method of adjusting the optical system of the plate alignment sensors 20a to 20d having the structure shown in FIGS. 6 and 14 will be described. FIG. 17 is a diagram for explaining a method of adjusting the plate alignment sensors 20a to 20d. Now, consider a case where the plate alignment sensor 20a measures the position information of the reference position mark 30b formed on the reference mark FM1. The reference mark FM1 is formed on the stage PS. The coordinates of the stage PS in the X-axis direction are measured by the laser interferometer 14X, and the coordinates in the Y-axis direction are measured by a laser interferometer 14Y (not shown). When the position information of the stage PS is measured by the laser interferometer 14X, the laser interferometer 14X
The movable mirror 13X as a reference member fixed above is irradiated with laser light, and the reflected light is detected to measure positional information in the X-axis direction.

Now, consider a case where the movable mirror 13X is attached to the stage PS while being inclined with respect to the optical axis ax of the plate alignment sensor 20a set in parallel with the Z axis shown in FIG. When the stage PS is moved only in the Z-axis direction, the main control system 15 controls the position information in the X-axis direction measured by the laser interferometer 13X via the stage driving system 16X (not shown) so as not to change. Therefore, when the stage PS is moved in the Z-axis direction, the movable mirror 13X moves in the direction indicated by reference numeral d1 in the figure. Therefore, when the stage PS is moved in the Z-axis direction, the laser interferometer 1
Although the position information in the X-axis direction measured by 4X does not change, since the reference mark FM1 moves along the locus TR1 in the figure, it moves in the XY plane in the direction indicated by the symbol d2 in the figure. In this case, when the reference mark FM1 moves in the direction indicated by the reference symbol d2 in the drawing, the image of the reference position mark 30b formed on the imaging surfaces of the image sensors 53 and 54 moves in the direction indicated by the reference symbol d3 in the drawing. Shift.

Therefore, in the main control system 15, the position of the reference position mark 30b is measured so as to shift as the stage PS moves in the Z-axis direction. When this shift occurs,
A problem arises not only when measuring the position information of the reference position mark 30b, but also when measuring the position information of the marks AM1 to AM4 formed on the plate P placed on the stage PS. Therefore, in the present embodiment, the disadvantage is solved by adjusting the optical system of the plate alignment sensors 20a to 20d. Specifically, the stage PS is set to Z
When the reference mark FM1 is moved in the axial direction, the reference mark FM1 moves along the locus TR1 shown in FIG.
The problem is solved by making the direction (optical axis) of the center of the light amount of light obtained by irradiating M1 with the detection light IL1 coincide with the locus TR1. For this reason, in the present embodiment, the detection light IL
By adjusting the position of one emission end 44b of the optical fiber 44 in a plane perpendicular to one optical axis, the reference mark FM
The irradiation direction of the detection light IL1 irradiating 1 is changed. For example, the position of the emission end 4b is adjusted by moving it in the direction indicated by the symbol d4 in the figure. The position of the emission end 44b is adjusted according to the inclination of the movable mirror 13X with respect to the optical axis ax (Z axis) of the plate alignment sensor 20a.

The means for matching the center of the light quantity (optical axis) of the light obtained by irradiating the detection light IL1 with the locus TR1 can be realized not only by adjusting the position of the end face 44b but also by the configuration shown in FIG. can do. FIG. 18 is a diagram illustrating another configuration example for adjusting the irradiation direction or position of the detection light IL1 with respect to the reference mark FM1. FIG. 18 (a)
The wedge-shaped prism 70 is provided in the optical path between the condenser lens 45 and the index plate 46 provided in the irradiation optical system of the plate alignment sensor 20a shown in FIG. 6 or FIG. The irradiation direction of IL1 is adjusted. Also, in the example shown in FIG. 18B, a parallel flat glass in which the angle formed with respect to the optical axis of the detection light IL1 between the exit end 44b of the optical fiber 44 and the condenser lens 45 is variable. By providing the reference mark 71, the irradiation direction of the detection light IL1 with respect to the reference mark FM1 is adjusted. By making such adjustments,
When the stage PS is moved in the Z-axis direction, it is possible to solve a problem that the mark is measured with a lateral shift. In addition, the above problem may occur when there is a manufacturing error in the movable mirrors 14X and 14Y, but such a case can be adjusted by the method described above.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and can be freely changed within the scope of the present invention. For example, in the above embodiment, the step-and-repeat type exposure apparatus has been described as an example, but the present invention is also applicable to a step-and-scan type exposure apparatus. In addition, the light source of the illumination optical system of the exposure apparatus of the present embodiment uses the g-line (436 nm) and the i-line (365 nm) emitted from the ultra-high pressure mercury lamp, but is not limited thereto, and the KrF excimer laser is used. (248 nm), ArF excimer laser (193n)
m), a laser beam emitted from an F ₂ laser (157 nm), or a charged particle beam such as an X-ray or an electron beam. For example, when an electron beam is used, a thermionic emission type lanthanum hexaborite (LaB ₆ ) or tantalum (Ta) can be used as an electron gun. Further, in the above-described embodiment, the case of manufacturing a liquid crystal display element has been described as an example. An exposure apparatus used to transfer a device pattern onto a semiconductor substrate, an exposure apparatus used to manufacture a thin-film magnetic head to transfer a device pattern onto a ceramic wafer, and an exposure apparatus used to manufacture an imaging device such as a CCD. The present invention can also be applied to

The index marks formed on the index plate provided in the position measuring device of the present invention are not limited to those shown in FIG. Further, the reference position marks 30b formed on the reference marks FM1 and FM2 and the marks AM1 to AM4 formed on the plate P are not limited to the shapes shown in FIG. The shapes of the index marks, the reference position marks 30b and the marks AM1 to AM4 formed on the plate P are as follows.
It can be appropriately designed according to processing such as image processing. For example, in the above embodiment, the mark image Im1 and the index mark image Im when formed on the imaging surface of the imaging device
As shown in FIG. 10, the relationship between the mark image Im2 and the mark image Im1 is surrounded by the mark image Im1 and the mark image Im1. It may be designed so that

Next, an embodiment of a method of manufacturing a micro device using an exposure apparatus in a lithography step according to an embodiment of the present invention will be described. FIG. 19 shows a micro device (a semiconductor chip such as an IC or an LSI, a liquid crystal panel,
FIG. 6 is a diagram showing a flowchart of a manufacturing example of a CCD, a thin-film magnetic head, a micromachine, and the like). As shown in FIG. 19, first, in step S90 (design step),
The function / performance design of the micro device (for example, the circuit design of a semiconductor device) is performed, and the pattern design for realizing the function is performed. Subsequently, in step S91 (mask manufacturing step), a mask (reticle) on which the designed circuit pattern is formed is manufactured. On the other hand, in step S92 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

Next, in step S93 (wafer processing step), using the mask and the wafer prepared in steps S90 to S92, an actual circuit or the like is formed on the wafer by lithography or the like as described later. . Next, in step S94 (device assembly step), device assembly is performed using the wafer processed in step S93. Step S94 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary.
Finally, in step S95 (inspection step), inspections such as an operation confirmation test and a durability test of the micro device manufactured in step S94 are performed. After these steps, the microdevice is completed and shipped.

FIG. 20 is a diagram showing an example of a detailed flow of step S93 in FIG. 19 in the case of a semiconductor device. In FIG. 18, in step S101 (oxidation step), the surface of the wafer is oxidized. In step S102 (CVD step), an insulating film is formed on the wafer surface. In step S103 (electrode formation step), electrodes are formed on the wafer by vapor deposition. In step S104 (ion implantation step), ions are implanted into the wafer. Step S10 above
Each of the steps 1 to S104 constitutes a pre-processing step in each stage of the wafer processing, and is selected and executed according to a necessary process in each stage.

In each stage of the wafer process, when the above-mentioned pre-processing step is completed, the post-processing step is executed as follows. In this post-processing step, first, step S
In 105 (resist forming step), a photosensitive agent is applied to the wafer. Subsequently, in step S106 (exposure step), the circuit pattern of the mask is transferred to the wafer by the lithography system (exposure apparatus) and the exposure method described above. Next, in step S107 (development step), the exposed wafer is developed, and in step S108 (etching step), the exposed members other than the portion where the resist remains are removed by etching. Then, in step S109 (resist removing step), unnecessary resist after etching is removed. By repeating these pre-processing and post-processing steps, multiple circuit patterns are formed on the wafer.

If the micro device manufacturing method of the present embodiment described above is used, an exposure step (step S106)
The above-described exposure apparatus and the above-described exposure method are used, and the resolution can be improved by the illumination light in the vacuum ultraviolet region, and the exposure amount can be controlled with high accuracy, and as a result, the minimum line width However, a highly integrated device of about 0.1 μm can be produced with high yield.

In addition to a micro device such as a semiconductor device, a reticle or a mask used in an optical exposure apparatus, an EUV exposure apparatus, an X-ray exposure apparatus, an electron beam exposure apparatus, or the like is manufactured using a mother reticle. The present invention is also applicable to an exposure apparatus that transfers a circuit pattern to a glass substrate, a silicon wafer, or the like. Here, in an exposure apparatus using DUV (deep ultraviolet) or VUV (vacuum ultraviolet) light, a transmission type reticle is generally used, and as a reticle substrate, quartz glass, fluorine-doped quartz glass, fluorite, Magnesium fluoride, quartz, or the like is used. In a proximity type X-ray exposure apparatus, electron beam exposure apparatus, or the like, a transmission mask (stencil mask, membrane mask) is used, and a silicon wafer or the like is used as a mask substrate. Such an exposure apparatus is described in WO99
No./34255, WO99 / 50712, WO99 /
66370, JP-A-11-194479, JP-A-2000-12453
And JP-A-2000-29202.

[0097]

As described above, according to the present invention,
The mark formed on the object is irradiated with the image of the index mark having a predetermined shape, the image of the mark and the image of the index mark are captured by the image sensor, and the relative image between the image of the mark captured by the image sensor and the image of the index mark is obtained. The position information of the mark is measured based on a typical positional relationship. Therefore, a relay optical system for forming an image of a mark on the index plate is not required as compared with a case where the index plate is arranged in the light receiving optical system, so that the apparatus is inexpensive and the size can be reduced. effective. Furthermore, since the position information of the mark is measured based on the relative relationship between the image of the mark and the image of the index mark, the position information can be obtained with high measurement accuracy as in the conventional position measurement device in which the index plate is arranged in the light receiving optical system. Information can be measured. Further, according to the present invention, the position information of the index mark on the imaging surface is measured in advance by using the reflection plate, and when the position information of the mark formed on the object is measured, the image is captured by the imaging device. The position information of the mark image is obtained, and the position information of the mark is measured based on the relative relationship between the position information and the position information of the index mark measured in advance. Therefore, when irradiating the image of the index mark to the mark, the contrast of the image of the index mark changes according to the surface state of the object, and the position information of the index mark cannot be measured. Even when it is not possible to determine the relative relationship based on the image of the index mark formed on the imaging surface of the image sensor and the image of the mark, the effect that the position information can be measured with high accuracy can be obtained. is there. Further, according to the present invention, there is provided a first correction optical system for correcting chromatic aberration generated in the irradiation optical system and a second correction optical system for correcting chromatic aberration generated in the light receiving optical system, and the correction amount is adjustable. . Therefore, chromatic aberration caused when using a broadband detection light can be prevented or reduced according to the amount of aberration in order to reduce the measurement error of the position information of the mark due to multiple interference on the surface of the object which occurs according to the surface state of the object. Therefore, there is an effect that a decrease in position measurement accuracy can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing an arrangement of members provided on a stage PS used when measuring various types of position information.

FIG. 3 is a cross-sectional view illustrating a configuration of a photoelectric measurement device used when obtaining a baseline amount on a stage PS.

FIG. 4 is a diagram showing an example of a slit pattern 30a and a reference position mark 30b formed on reference marks FM1 and FM2.

FIG. 5 is an enlarged view of a reference position mark 30b.

FIG. 6 is a diagram showing a first configuration example of an optical system of plate alignment sensors 20a to 20d forming a part of the position measurement device according to one embodiment of the present invention.

FIG. 7 is a diagram showing an example of the shape of an index mark 47 formed on an index plate 46.

FIG. 8 is an enlarged view of a second light shielding portion 47b.

FIG. 9 is a flowchart illustrating a schematic operation of the exposure apparatus according to the embodiment of the present invention when measuring a baseline amount.

FIG. 10 is a diagram illustrating an example of an image of a reference mark FM1 and an image of an index mark formed on an imaging surface of an imaging element 54 at a high magnification.

FIG. 11 is a schematic diagram showing an arrangement relationship of marks formed on a plate P;

FIG. 12 shows plate alignment sensors 20a to 20
marks AM1 to AM formed on plate P using
4 is a flowchart showing an operation when measuring position information of No. 4;

FIG. 13 shows plate alignment sensors 20a to 20
12 is a flowchart illustrating a process for obtaining the center position of the index mark image Im2 with respect to the imaging surfaces of the imaging elements 53 and 54 in d.

FIG. 14 shows plate alignment sensors 20a to 20d forming a part of a position measuring device according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a second configuration example of the optical system of FIG.

15A and 15B are diagrams for explaining the principle that chromatic aberration can be corrected using the direct-view prisms 60a and 60b or the direct-view prisms 61a and 61b, and FIG. 15A illustrates the direct-view prisms 60a and 60b or the direct-view prisms 61a and 61b. (B) is an arrow view as viewed from the direction indicated by the symbol A1 in (a), and (c) is the symbol A2 in (a).
It is the arrow view seen from the direction attached.

FIG. 16 is a flowchart illustrating a procedure of a method of adjusting a correction direction and a correction amount of chromatic aberration in the plate alignment sensor 20a.

FIG. 17 shows plate alignment sensors 20a to 20
It is a figure for explaining the adjustment method of d.

FIG. 18 is a diagram illustrating another configuration example of adjusting the irradiation direction or position of the detection light IL1 with respect to the reference mark FM1.

FIG. 19 is a view showing a flowchart illustrating an example of the manufacturing process of the micro device.

FIG. 20 is a diagram showing an example of a detailed flow of step S93 in FIG. 19 in the case of a semiconductor device.

FIG. 21 is a diagram illustrating a configuration of an optical system of a conventional position measuring device that is an off-axis system and an FIA system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Elliptical mirror (illumination optical system) 2 Light source (illumination optical system) 3 Mirror (illumination optical system) 4 Collector lens (illumination optical system) 5 Dimming filter (illumination optical system) 6 Fly-eye integrator (illumination optical system) 7 Half mirror (illumination optical system) 8 Lens (illumination optical system) 9 Blind (illumination optical system) 10 Lens (illumination optical system) 11 Mirror (illumination optical system) 13X, 13Y Moving mirror (reference member) 15 Main control system (processing) 16X, 16Y Stage drive system (positioning means) 30b Reference position mark (mark) 45 Condenser lens (irradiation optical system, optical system) 46 Index plate 47 Index mark 47a First light shield 47b Second light shield Section 48 Relay lens (irradiation optical system, optical system) 49 Half mirror (irradiation optical system, light receiving optical system, optical system) 50 Objective lens ( Projection optical system, light receiving optical system, optical system 51 Second objective lens (light receiving optical system, optical system) 52 Beam splitter (light receiving optical system, optical system) 53 Image sensor (light receiving optical system, optical system) 54 Image sensor ( Receiving optical system, optical system) 60 First correction optical system 60a, 60b Direct-view prism (irradiation-side adjustment member) 61 Second correction optical system 61a, 61b Direct-view prism (reception-side adjustment member) 70 Wedge-shaped prism (adjustment means) 71 Parallel flat glass (adjustment means) AM1 to MA4 mark FC Image forming surface (image forming position) FM1, FM2 Reflector (object, reflecting surface) IL1 Detection light Im1 Mark image Im2 Index mark image M1 to M4 Mask P plate (Object, substrate) PL Projection optical system PS stage q1 to q4 Cross-shaped light shielding unit

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 21/30 525B (72) Inventor Manabu Toguchi Nikon Corporation (2-3-3, Marunouchi, Chiyoda-ku, Tokyo) (72 ) Inventor Yutaka Hobiki 3-2-3 Marunouchi, Chiyoda-ku, Tokyo F-term in Nikon Corporation (reference) LL22 LL24 LL30 LL46 LL50 MM02 NN03 PP12 QQ39 RR08 UU05 UU09 5F046 BA04 DA14 ED01 ED02 FA06 FA10 FA17 FB02 FB11 FB17

Claims (15)

[Claims] 1. An irradiation optical system for irradiating a mark formed on an object with detection light, a light receiving optical system for receiving light obtained by irradiating the mark with the detection light, and a light receiving result of the light receiving optical system A processing system for obtaining position information of the mark based on the position measurement device, wherein the predetermined position is set in the irradiation optical system at a position substantially optically conjugate with an image forming position of the detection light, A position measuring device comprising an index plate having an index mark of a shape. A first light-shielding portion configured to shape the detection light into a rectangular shape; and a second light-shielding portion configured to shield a part of the detection light shaped into a rectangular shape into an annular shape having four sides. The position measuring device according to claim 1, wherein 3. The position measuring device according to claim 2, wherein a cross-shaped light-shielding portion is formed at four corners of the second light-shielding portion. 4. A first correction optical system for correcting chromatic aberration generated in the irradiation optical system by a wavelength difference in a wavelength band of the detection light, and a wavelength of light obtained by irradiating the object with the detection light. The position measuring apparatus according to any one of claims 1 to 3, further comprising a second correction optical system that corrects chromatic aberration generated in the light receiving optical system due to a wavelength difference within a band. . 5. The first correction optical system includes at least one irradiation-side adjustment member rotatable with respect to an optical axis of the irradiation optical system in order to adjust a correction amount of chromatic aberration of the irradiation optical system. The second correction optical system has at least one light receiving side adjustment member rotatable with respect to an optical axis of the light receiving optical system in order to adjust a correction amount of chromatic aberration of the light receiving optical system. The position measuring device according to claim 4, characterized in that: 6. The position measuring apparatus according to claim 1, further comprising an adjusting unit that adjusts an incident direction of the detection light on the object. 7. irradiating a mark formed on an object with an image of an index mark having a predetermined shape; capturing an image of the mark and an image of the index mark using an image sensor; Obtaining the position information of the mark based on the relative positional relationship between the image of the mark and the image of the index mark which has been taken. 8. An image of the index mark is radiated to a predetermined reflection surface prior to measurement of the position information of the mark, and an image of the index mark reflected by the reflection surface is captured by the imaging device. The method further includes a step of previously obtaining position information of an image of the index mark in an imaging surface of an imaging device, and the step of measuring the position information of the mark is performed in the imaging surface obtained before the measurement of the mark. The position information of the mark is measured based on a relative relationship between the position information of the image of the index mark and the position information of the image of the mark picked up by the image pickup device on the image pickup surface. The position measuring method according to claim 7. 9. A first shift detecting step of guiding light of a plurality of different wavelengths from the first reference mark to a light receiving optical system and detecting a relative positional shift of the first reference mark for each wavelength, A first adjusting step of adjusting the light receiving optical system based on the detection result of the first shift detecting step; A second shift detecting step of detecting a relative position shift of the second reference mark for each, a second adjusting step of adjusting the irradiation optical system from a detection result of the second shift detecting step, Irradiating the surface to be detected with detection light including light having a plurality of wavelengths different from each other by: The inspection formed on the surface to be inspected. Position measuring method characterized by comprising a mark detection step of detecting the positional information of the mark. 10. An exposure apparatus for irradiating illumination light emitted from an illumination optical system onto a mask and transferring an image of a pattern formed on the mask onto a substrate via a projection optical system, wherein the exposure apparatus The position measurement device according to any one of claims 1 to 6, which measures position information of a mark formed on the substrate, and the relative position of the substrate with respect to the mask based on a measurement result of the position measurement device. An exposure apparatus comprising: positioning means for performing positioning. 11. A step of measuring position information of a substrate using the position measurement method according to claim 7, and a step of determining a relative position between the mask and the substrate based on the measurement result. Performing an accurate alignment; irradiating the mask with illumination light; and transferring an image of a pattern formed on the mask onto the substrate via a projection optical system; and Developing the micro device. 12. A stage on which an object is placed, and a detection light is applied to a mark formed on the object,
An optical system for measuring position information of the mark using light from the mark; a reference member fixed to the substrate stage; and a position of the mark caused by an installation error or a manufacturing error of the reference member. A position measuring device comprising: an adjusting unit that adjusts an irradiation direction or a position of the detection light to the mark according to an installation error or a manufacturing error of the reference member in order to correct an information error. . 13. An illumination optical system for illuminating the mask with exposure illumination light to transfer an image of a pattern formed on the mask to a photosensitive substrate, and a position of a substrate mark formed on the photosensitive substrate. 13. An exposure apparatus comprising: the position measurement device according to claim 12, wherein the information is detected as position information of a mark formed on the object. 14. A light-receiving step of irradiating a mark on an object placed on a stage with a reference member with detection light and receiving light from the mark, and measuring position information of the reference member. A measuring step; a detecting step of obtaining position information of the mark based on light receiving information from the light receiving step and measurement information from the measuring step; and a position of the object caused by an installation error or a manufacturing error of the reference member. An adjustment step of adjusting an irradiation direction or a position of the detection light to the mark according to an installation error or a manufacturing error of the reference member in order to correct an information error. 15. A substrate position measuring step of measuring position information of a substrate using the position measuring method according to claim 14, and positioning of a mask and the substrate based on a measurement result in the substrate position measuring step. An alignment step, an exposure step of transferring an image of a pattern formed on the mask to the substrate, and a developing step of developing the substrate on which the image of the pattern has been transferred. Production method.