JP4788229B2 - Position detection apparatus, alignment apparatus, exposure apparatus, and microdevice manufacturing method - Google Patents

Description

  The present invention uses a position detection apparatus used in a lithography process for manufacturing a semiconductor element, a liquid crystal display element, and the like, an alignment apparatus including the position detection apparatus, an exposure apparatus including the position detection apparatus, and the exposure apparatus. The present invention relates to a method for manufacturing a microdevice.

  In a lithography process for manufacturing a semiconductor element or the like, a pattern formed on a reticle (or mask) is transferred onto a wafer (or glass plate or the like) coated with a resist (photosensitive agent) on the surface via a projection optical system. An exposure apparatus is used. For example, a step-and-repeat reduction projection exposure apparatus (so-called stepper), a step-and-scan scanning projection exposure apparatus (scanning stepper) that synchronously scans a reticle and a wafer, and the like are generally used.

  With high integration of semiconductor elements and miniaturization of patterns, high resolution (high resolution) is required for exposure apparatuses. In the projection exposure apparatus, exposure is performed by positioning the wafer surface within the range of the depth of focus (DOF) of the image plane of the projection optical system (the best imaging plane of the pattern) in order to prevent image blur due to defocusing. Need to do. However, if the exposure wavelength is shortened and the numerical aperture (NA) is increased in order to increase the resolution, the depth of focus becomes narrower. Therefore, in a scanning projection exposure apparatus, in order to position the wafer surface within the range of the depth of focus of the image plane of the projection optical system, a focus sensor for measuring the wafer surface and wafer stage control are used to control the wafer surface during scanning exposure. The focus error due to the inclination or undulation in the exposed area is corrected.

  However, in recent years, the resolution has further increased and the depth of focus has further narrowed, and in addition to the focus error due to the wafer surface tilt and waviness, the focus error due to reticle deflection has become a problem. That is, the shape of the image plane of the projection optical system changes according to the deflection of the reticle lower surface (pattern surface). Here, a focus sensor that measures the position of the lower surface of the reticle is used in order to correct a focus error caused by bending of the lower surface of the reticle (see, for example, Patent Document 1).

JP-A-7-86154

  However, since a reticle stage configured to hold and move the reticle is disposed between the reticle and the projection optical system, it is used for measuring the wafer surface as a focus sensor for measuring the lower surface of the reticle. When a grazing incidence type focus sensor is used, there is a problem that a sufficiently large incident angle cannot be obtained and a measurement error tends to occur. Further, when an oblique incidence type focus sensor is used, there is a problem that a measurement error occurs due to the pellicle film formed on the lower surface of the reticle. In addition, the conventional focus sensor for measuring the lower surface of the reticle has a problem that it cannot be installed easily and compactly even though the space where the reticle can be installed is limited. In addition, there is a problem that the position (plural positions) in a wide area on the lower surface of the reticle cannot be measured.

  An object of the present invention is to provide a position detection device having a compact and simple configuration and capable of detecting a plurality of positions on a test surface, an alignment device including the position detection device, and an exposure including the position detection device. An apparatus and a method of manufacturing a micro device using the exposure apparatus are provided.

The position detection device of the present invention is a position detection device that irradiates a test surface with light and detects the position of the test surface based on the light reflected by the test surface. A first optical system that forms a first conjugate position that is optically conjugate; a confocal optical system that forms a second conjugate position that is optically conjugate with the test surface and the first conjugate position; and A reference member arranged at a conjugate position;
A light receiving unit that includes a pinhole disposed at the second conjugate position and that receives light via the confocal optical system and the pinhole; and a position of the test surface based on light reception information of the light receiving unit. A processing unit for calculating, wherein the light receiving unit receives first light reflected by the test surface and second light reflected by the reference member, and the processing unit includes: The position of the test surface is calculated based on the light reception information of the first light and the light reception information of the second light .
The position detection apparatus of the present invention is a position detection apparatus that irradiates a test surface with light and detects the position of the test surface based on light reflected by the test surface. A first optical system that forms a first conjugate position that is optically conjugate with a surface; a second optical system that forms a second conjugate position that is optically conjugate with the test surface and the first conjugate position; A test surface, a confocal optical system that forms a third conjugate position optically conjugate with the first conjugate position and the second conjugate position, a reference member disposed at the first conjugate position, and the third A light receiving unit that includes a pinhole disposed at a conjugate position, and that receives light via the second optical system, the confocal optical system, and the pinhole; A processing unit that calculates the position of the light receiving unit, and The first light and the second light reflected by the reference member are respectively received, and the processing unit is based on the light reception information of the first light and the light reception information of the second light. The position of the test surface is calculated.

  According to the position detection apparatus of the present invention, since the relay optical system that guides the measurement light to different positions in the test surface is provided, a plurality of positions on the test surface can be detected, and a wide area of the test surface is obtained. The position inside can be detected accurately in a shorter time. Further, since the confocal optical system is provided, an apparatus having a compact and simple configuration can be provided. Therefore, when the position detection device is mounted on the exposure apparatus to detect the position of the mask, it can be easily installed and the position of the mask can be detected with high accuracy.

The alignment apparatus of the present invention performs alignment of the first surface and the second surface by detecting a first mark provided on the first surface and a second mark provided on the second surface. a alignment apparatus, characterized by comprising a position detecting device of the present invention for detecting the position of said first surface.

  According to the alignment apparatus of the present invention, since the position of the first surface can be accurately detected by the position detection apparatus of the present invention, the first surface and the second surface can be more accurately aligned.

The exposure apparatus of the present invention, in an exposure apparatus for exposing a pattern of a mask onto a photosensitive substrate, characterized in that it comprises a position detecting device of the present invention for detecting the position of the surface of the mask.

  According to the exposure apparatus of the present invention, since the position detection device that can detect the position of the mask with high accuracy is provided, it is possible to accurately detect an imaging error on the photosensitive substrate due to the deflection of the mask or the like. Can do. Therefore, the photosensitive substrate can be exposed with high resolution.

The microdevice manufacturing method of the present invention includes an exposure step of exposing a predetermined pattern on a photosensitive substrate using the exposure apparatus of the present invention , and a development of developing the photosensitive substrate exposed by the exposure step. And a process.

  According to the microdevice manufacturing method of the present invention, since exposure is performed using an exposure apparatus that can expose a photosensitive substrate with high resolution, a good microdevice can be obtained.

  According to the position detection apparatus of the present invention, since the relay optical system that guides the measurement light to different positions in the test surface is provided, a plurality of positions on the test surface can be detected, and a wide area of the test surface is obtained. The position inside can be detected accurately in a shorter time. Further, since the confocal optical system is provided, an apparatus having a compact and simple configuration can be provided. Therefore, when the position detection device is mounted on the exposure apparatus to detect the position of the mask, it can be easily installed and the position of the mask can be detected with high accuracy.

  According to the alignment apparatus of the present invention, since the position of the first surface can be accurately detected by the position detection apparatus of the present invention, the first surface and the second surface can be more accurately aligned.

  According to the exposure apparatus of the present invention, since the position detection device that can detect the position of the mask with high accuracy is provided, it is possible to accurately detect an imaging error on the photosensitive substrate due to the deflection of the mask or the like. Can do. Therefore, the photosensitive substrate can be exposed with high resolution.

  According to the microdevice manufacturing method of the present invention, since exposure is performed using an exposure apparatus that can expose a photosensitive substrate with high resolution, a good microdevice can be obtained.

  A projection exposure apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a projection exposure apparatus according to this embodiment. The projection exposure apparatus according to this embodiment includes a position detection device 2 for detecting a plurality of positions of a reticle (test surface) R as a mask. In this embodiment, the Z axis is parallel to the optical axis of the projection optical system PL, and the X axis is perpendicular to the Z axis in a direction parallel to the plane of FIG. 1 in a plane perpendicular to the Z axis. The Y axis is set in a direction perpendicular to the paper surface of FIG.

  As shown in FIG. 1, the projection exposure apparatus includes an illumination optical system IL having an optical system 4 including a light source, a condenser lens 6 and a mirror 8. The projection exposure apparatus also includes a reticle stage RST that supports the reticle R substantially parallel to the XY plane, and a reticle base RBS that supports the reticle stage RST substantially parallel to the XY plane. On the lower surface of the reticle R, a pattern to be transferred onto a wafer W as a photosensitive substrate is formed. FIG. 2 is a top view showing the configuration of reticle stage RST and its peripheral part. Reticle stage RST is configured to be movable two-dimensionally in an XY plane perpendicular to the optical axis of projection optical system PL. Further, a movable mirror (not shown) that reflects a laser beam from a reticle laser interferometer (not shown) is fixed on the reticle stage RST, and the position of the reticle stage RST in the XY plane is the reticle laser. Detected and controlled by an interferometer.

  In addition, a reticle fiducial mark plate (hereinafter referred to as a reticle mark plate) RFM on which a reticle position reference mark is formed is arranged in line with the reticle R in the vicinity of the + X direction end of the reticle stage RST. Yes. The reticle stage RST has an opening 10a (indicated by a chain line in FIG. 1) for allowing exposure light to pass through the illumination optical system IL below the reticle R, and an opening for allowing the exposure light to pass below the reticle mark plate RFM. 10b (shown by a chain line in FIG. 1) is formed. In addition, an opening 11a (indicated by a chain line in FIG. 1) serving as a passage for exposure light passes almost directly above the projection optical system PL of the reticle base RBS to allow measurement light emitted from the position detection device 2 described later to pass therethrough. An opening 11b (shown by a chain line in FIG. 1) is formed.

  At the time of exposure, the illumination area of the reticle R is arranged on the opening 11a by moving the reticle stage RST in the X direction. The exposure light emitted from the illumination optical system IL passes through the illumination area of the reticle R and the opening 11a. The exposure light that has passed through the opening 11a reaches the exposure area on the wafer W coated with the photoresist as the photosensitive material via the both-side telecentric projection optical system PL, and the pattern of the reticle R is formed on the wafer W. An image is formed. Note that a variable aperture stop (not shown) for controlling the numerical aperture of the projection optical system PL is installed on or near the pupil plane of the projection optical system PL.

  Wafer W is placed on wafer table WT via wafer holder WH, and wafer table WT is placed on wafer stage WST. Wafer stage WST includes a Z stage 12 and an XY stage 13. The Z stage 12 is mounted on the XY stage 13, and is configured to be movable in the optical axis direction (Z direction) of the projection optical system PL, the rotation direction around the X axis, and the rotation direction around the Y axis. The XY stage 13 is mounted on the surface plate WBS, and is configured to be two-dimensionally movable in an XY plane perpendicular to the optical axis of the projection optical system PL. A movable mirror (not shown) that reflects a laser beam from a wafer laser interferometer (not shown) is fixed on the wafer table WT, and the position of the wafer table WT in the XY plane is the wafer laser interferometer. Detected and controlled by

  The projection exposure apparatus includes a position detection device 2 that can detect a plurality of positions of the reticle R in order to measure the deflection of the reticle R that causes a focus error of the projection optical system PL. As shown in FIG. 1, the position detection device 2 is disposed between the reticle base RBS and the projection optical system PL. FIG. 3 is a diagram illustrating a configuration of the position detection device 2. As shown in FIG. 3, the position detection device 2 includes a confocal microscope 14.

  FIG. 4 is a diagram illustrating the configuration of the confocal microscope 14. As shown in FIG. 4, measurement light (laser light) emitted from a light source unit 16 such as a laser diode (LD) passes through a half mirror 18 and a focus adjustment lens 20 and is reflected by a galvanometer mirror 22. . The galvanometer mirror 22 is configured to be rotatable in the direction of arrow a in the figure. The measurement light reflected by the galvanometer mirror 22 passes through the lens 24 and the collimator lens 26. The focus adjustment lens 20, galvanometer mirror 22, lens 24, and collimator lens 26 constitute a confocal optical system, and the collimator lens 26 is parallel to the optical axis direction of the confocal optical system (arrow direction b in the figure). It is configured to be movable. The measurement light that has passed through the collimator lens 26 is condensed at the focal position F of the confocal optical system.

  FIG. 5 is a diagram illustrating how the traveling direction of the measurement light changes when the galvano mirror 22 is rotated. As shown in FIG. 5, when the galvano mirror 22 is rotated, the traveling direction of the measurement light changes in a direction perpendicular to the optical axis direction of the confocal optical system (arrow direction c in the figure). Specifically, when the galvanometer mirror 22 is rotated clockwise around the center of the galvanometer mirror 22, the traveling direction of the measurement light changes upward as compared with the optical axis of the confocal optical system. Further, when the galvano mirror 22 is rotated counterclockwise about the center of the galvano mirror 22, the traveling direction of the measurement light changes downward as compared with the optical axis of the confocal optical system.

  FIG. 6 is a diagram showing how the focal position of the confocal optical system changes when the collimator lens 26 is moved in the optical axis direction. As shown in FIG. 6, when the collimator lens 26 is moved in the optical axis direction, the focal position F of the confocal optical system is in a direction parallel to the optical axis direction of the confocal optical system (arrow direction d in the figure). Change. Specifically, when the collimator lens 26 is moved in the right side (lens 24 side) direction in the figure, the focal position F of the confocal optical system moves to the right side in the figure. Further, when the collimator lens 26 is moved in the left direction in the figure, the focal position F of the confocal optical system moves to the left side in the figure. In the confocal microscope 14 according to this embodiment, the position of the test object can be measured by moving the focal position F of the confocal optical system using the collimator lens 26. Assuming that the test surface is placed near the focus position F of the confocal optical system, the test object position becomes the focus position of the collimator lens 26 by moving the focus position F using the collimator lens 26. In this case, the amount of light received by the light receiving sensor 46 is maximized. Therefore, the focal position F where the amount of received light is maximum can be specified from the position information of the collimator lens 26, and as a result, the position of the test object can be measured.

  As shown in FIG. 3, the measurement light that has passed through the collimator lens 26 constituting the confocal microscope 14 includes a beam expander (intermediate relay optical system) 28a, parallel plane plates 30, 32, and a beam expander (intermediate relay optical system). ) Pass 28b. The beam expanders 28a and 28b expand measurement light from the confocal optical system (collimator lens 26) under a predetermined magnification. In this embodiment, the diameter of the laser beam spot at the exit position of the confocal microscope 14 is enlarged by, for example, 20 times at the position of the field stop 34 with respect to the diameter of the laser beam spot.

  By enlarging the measurement light, the influence of errors caused by air fluctuation around the later-described field stop 34 surface (optically conjugate surface with the reticle R lower surface, which is the test surface) and a complicatedly configured rear lens, can be reduced. Optical stability can be obtained without receiving, and the position of the reticle R can be detected with high accuracy using the field stop 34 as a reference plane.

  The plane parallel plates 30 and 32 are configured to be tiltable with respect to the optical axes of the beam expanders 28a and 28b. By tilting the plane parallel plates 30 and 32, the optical axis of the optical system constituting the position detection device 2 can be adjusted.

  The enlarged measurement light that passes through the beam expander 28 b reaches the field stop (reference member) 34. The field stop 34 is disposed at a position optically conjugate with the focal position F of the confocal optical system. FIG. 7 is a diagram showing the configuration of the field stop 34. As shown in FIG. 7, the field stop 34 has a reference pattern including a plurality (three in this embodiment) of slits 34 a to 34 c arranged in parallel along the short direction (X direction). Yes.

  Here, the galvanometer mirror 22 constituting the confocal microscope 14 can be made to function as a selection means for selectively guiding the measurement light to different positions within the surface of the field stop 34 (and thus the lower surface of the reticle R). That is, as described above, since the traveling direction of the measurement light can be changed by rotating the galvanometer mirror 22, any one of the slits 34 a to 34 c of the field stop 34 is rotated by rotating the galvanometer mirror 22. The traveling direction of the measurement light can be selected so as to pass through the two. In this embodiment, the confocal microscope 14 is arranged by rotating it around the Y axis by a certain angle, so that the incident position of the measurement light with respect to the field stop 34 is slits 34a to 34c as indicated by L1 to L3 shown in FIG. It is changed in an oblique direction with respect to the longitudinal direction. The measurement light is incident on any one of the slits 34a to 34c.

  Note that the measurement light can be selectively guided to different positions in the reticle R by moving the reticle stage RST in a direction (X direction) orthogonal to the scanning direction.

  Moreover, the galvanometer mirror 22 which comprises the confocal microscope 14 can be functioned as a scanning means to scan measurement light. When the position of the galvano mirror 22 as the selection unit is set so that the measurement light is incident on the slit 34a, the galvano mirror 22 as the scanning unit is rotated within the range of a predetermined angle ± θ around the position. Then, the measurement light scans within the range of L1. Further, when the position of the galvano mirror 22 as the selection unit is set so that the measurement light is incident on the slit 34b, the galvano mirror 22 as the scanning unit is rotated within a range of a predetermined angle ± θ around the position. When moved, the measurement light scans within the range of L2. When the position of the galvano mirror 22 as the selection unit is set so that the measurement light is incident on the slit 34c, the galvano mirror 22 as the scanning unit is rotated within a range of a predetermined angle ± θ around the position. When moved, the measurement light scans within the range of L3. As described above, when scanning is performed in a direction having a predetermined angle with respect to the longitudinal direction of the slits 34a to 34c, it will be described later as compared with a case where scanning is performed in a direction parallel to the lateral direction of the slits 34a to 34c. More measurement points by the light receiving sensor 46 can be obtained. The measurement light can also be scanned by moving the reticle stage RST in a direction (X direction) orthogonal to the scanning direction.

  The case where the position of the galvanometer mirror 22 as the selection means is set so that the measurement light is incident on the slit 34b and the galvanometer mirror 22 as the scanning means is rotated within the range of a predetermined angle ± θ with the position as the center will be described. To do. As shown in FIG. 3, when the measurement light I2 passes through the slit 34b of the field stop 34, the measurement light I2 enters the mirror 38b via the relay optical system (detection optical system) 36b. The measurement light I2 reflected by the mirror 38b reaches the measurement point 42b on the lower surface of the reticle R via the relay optical system (detection optical system) 40b. By the relay optical systems (detection optical systems) 36b and 40b, the measurement light (beam spot) at the field stop position is reduced to the lower surface of the reticle under a predetermined reduction magnification. In this embodiment, the magnification from the field stop position to the reticle lower surface is reduced to 1/15 times, for example. On the reticle R, a beam spot of about 2.7 μm is formed.

  A part of the lens (not shown) constituting the relay optical system 40b is configured to be movable in the optical axis direction of the relay optical system 40 and in a direction orthogonal to the optical axis direction. By moving a part of the lens constituting the relay optical system 40b in the optical axis direction, the spherical aberration of the optical system constituting the position detection device 2 can be corrected. Further, the coma aberration of the optical system constituting the position detection device 2 can be corrected by moving a part of the lens constituting the relay optical system 40b in a direction orthogonal to the optical axis direction. The influence of the aberration of the optical system constituting the position detection device 2 will be described later.

  The measurement light reflected by the measurement point 42b is confocal again via the relay optical system 40b, the mirror 38b, the relay optical system 36b, the slit 34b, the beam expander 28b, the parallel plane plates 32 and 30, and the beam expander 28a. The microscope 14 is reached. On the other hand, the measurement light I2 that does not pass through the slit 34b of the field stop 34 by scanning the measurement light I2 and is reflected by the field stop 34 passes through the beam expander 28b, the parallel flat plates 32 and 30, and the beam expander 28a. Via the confocal microscope 14.

  The case where the position of the galvano mirror 22 as the selection unit is set so that the measurement light enters the slit 34a and the galvano mirror 22 as the scanning unit is rotated within the range of a predetermined angle ± θ with the position as the center will be described. To do. As shown in FIG. 3, when the measurement light I1 passes through the slit 34a of the field stop 34, the measurement light I1 is sequentially reflected by the field division mirrors (field division members) 48a and 50a. The field dividing mirrors 48a and 50a are configured to be tiltable in the optical axis direction of the relay optical system 36b. By tilting the field division mirrors 48a and 50a integrally, correction is performed to make the traveling direction of the measuring light I1 coincide with the optical axis direction of the relay optical system 36b.

  The measurement light I1 reflected by the field dividing mirror 50a is reflected by the mirror 38a via the relay optical system 36a, and further reaches 42a different from the measurement point 42b on the lower surface of the reticle R via the relay optical system 40a. By using the relay optical systems 36a and 40a, the image is reduced under a predetermined reduction magnification. The measurement accuracy of the reticle R surface is improved by reducing the measurement light I1 enlarged by the beam expanders 28a and 28b. The relay optical system 40a has the same configuration as the relay optical system 40b. The measurement light reflected by the measurement point 42a is again transmitted to the relay optical system 40a, the mirror 38a, the relay optical system 36a, the field dividing mirrors 50a and 48a, the slit 34a, the beam expander 28b, the parallel plane plates 32 and 30, and the beam expander. The confocal microscope 14 is reached via 28a. On the other hand, the measurement light I1 reflected by the field stop 34 without passing through the slit 34a of the field stop 34 by scanning the measurement light I1 passes through the beam expander 28b, the parallel plane plates 32 and 30, and the beam expander 28a. Via the confocal microscope 14.

  The case where the position of the galvanometer mirror 22 as the selection means is set so that the measurement light is incident on the slit 34c and the galvanometer mirror 22 as the scanning means is rotated within the range of a predetermined angle ± θ with the position as the center will be described. To do. As shown in FIG. 3, when the measurement light I3 passes through the slit 34c of the field stop 34, the measurement light I3 is sequentially reflected by the field division mirrors 48c and 50c. The field division mirrors 48c and 50c have the same shape and function as the field division mirrors 48a and 50a. The measurement light I3 reflected by the field dividing mirror 50c is reflected by the mirror 38c via the relay optical system 36c, and further reaches 42c different from the measurement points 42a and 42b on the lower surface of the reticle R via the relay optical system 40c. To do. The measurement light I3 is reduced under a predetermined reduction magnification through the relay optical systems 36c and 40c. The relay optical system 40c has the same configuration as the relay optical system 40b. The measurement light reflected by the measurement point 42c is again transmitted to the relay optical system 40c, the mirror 38c, the relay optical system 36c, the field dividing mirrors 50c and 48c, the slit 34c, the beam expander 28b, the parallel plane plates 32 and 30, and the beam expander. The confocal microscope 14 is reached via 28a. On the other hand, the measurement light I3 reflected by the field stop 34 without passing through the slit 34c of the field stop 34 by scanning the measurement light I3 passes through the beam expander 28b, the parallel plane plates 32 and 30, and the beam expander 28a. Via the confocal microscope 14.

  As shown in FIG. 4, the measurement lights I1 to I3 that have reached the confocal microscope 14 are reflected by the half mirror 18 through the collimator lens 26, the lens 24, the galvanometer mirror 22, and the focus adjustment lens 20, and are pinholes. The light passes through 44 and enters the light receiving sensor 46. Position information when the collimator lens is driven in the optical axis direction (that is, position information of the focal position F of the confocal optical system) and light quantity information of the measurement light received by the light receiving sensor 46 are the control device (detecting means). 56 is output. The control device 56 detects the position of the reticle R based on the two pieces of information. That is, as shown in FIG. 8, the position of the galvano mirror 22 as the selection means is set so that the measurement light is incident on the slit 34b, and the galvano as the scanning means is within a range of a predetermined angle ± θ around the position. An example will be described in which the measurement light I2 scans the range of L2 in the direction of the arrow in the figure by rotating the mirror 22.

  Seven measurements in which the position measurement result obtained by processing the output signal from the light receiving sensor 46 and the focal position information of the confocal optical system by the control device 56 is measured by scanning the measurement light in the arrow direction shown in FIG. It is assumed that it is obtained at points r1 to r7. Since the scanning of the measurement light is started, the measurement results at the measurement points r1 and r2 measured by the light receiving sensor 46 first do not pass through the slit 34b, and thus the measurement result of the measurement light reflected by the slit 34 is shown. The scanning of the measurement light is continued, and the measurement result at the measurement points r3 to r5 measured by the light receiving sensor 46 next passes through the slit 34b, so that the measurement light reflected by the reticle R (measurement point 42b) is reflected. Measurement results are shown. The scanning of the measurement light is continued, and the measurement results at the measurement points r6 and r7 measured by the light receiving sensor 46 next do not pass through the slit 34b. Therefore, the measurement results of the measurement light reflected by the slit 34 are shown.

  The control device 56 calculates the focus position of the test surface (reticle R) by performing the following difference processing from the individual measurement results of r1 to r7. FIG. 9 is a graph showing the focus position (vertical axis) calculated by the control device 56 and the position of the measurement light (horizontal axis) at that time. As shown in FIG. 9, solid lines G1 and G3 in FIG. 9 are focus positions when reflected by the slit 34, and solid lines G2 in FIG. 9 are focus positions when reflected by the reticle R (measurement point 42b). is there. Since the position of the slit 34 serving as the reference surface is defined in advance, based on the difference D between the focus position when reflected by the slit 34 and the focus position when reflected by the reticle R (measurement point 42b). The position of the reticle R at the measurement point 42b can be calculated.

  The position of the galvanometer mirror 22 as the selection means is set so that the measurement light is incident on the slits 34a and 34c, and the galvanometer mirror 22 as the scanning means is rotated within the range of a predetermined angle ± θ around the position. Thus, even when the measurement lights I1 and I3 scan within the range of L1 and L3, the focus position when reflected by the slit 34 and the case where the measurement light I1 and I3 are reflected by the reticle R (measurement points 42a and 42c) Based on the difference from the focus position, the position of the reticle R at the measurement points 42a and 42c can be calculated.

  FIG. 10 is a diagram illustrating a positional relationship between the measurement points 42a to 42c and the reticle R surface. As shown in FIG. 10, the measurement points 42 a to 42 c are arranged in a line at a predetermined interval in the Y direction of the reticle R. Accordingly, the measurement points 42a to 42c on the reticle R surface are moved in the X direction by scanning the reticle stage RST in the X direction, and the positions of the measurement points 42a to 42c changing in the X direction are continuously or at predetermined intervals. By measuring every time, the position of the entire surface of the reticle R can be measured.

  In the position detection device 2, an exposure pattern is formed on the lower surface of the reticle R, which is the test surface. Further, the reticle is a glass substrate and its lower surface is not completely flat. If the pattern edge or fine pattern of the reticle R enters the beam spot of the measurement light, a measurement error by the light receiving sensor 46 may occur due to the interaction with the aberration of the optical system. As shown in FIG. 11, the light incident on the pinhole 44 of the confocal microscope (FIG. 4) becomes a conical condensed light, and the light receiving angle is defined by the numerical aperture (NA). Consider a circular region R (hereinafter referred to as pupil plane R) with a conical light beam cross-section sufficiently away from the pinhole 44. As shown in FIG. 12, since the transmitted laser beam is usually a Gaussian beam, the light intensity distribution on the pupil plane R spreads uniformly over the central object as a Gaussian distribution. However, the measurement light is diffracted by the influence of the pattern edge of the reticle R and the fine pattern, and the luminous intensity distribution is deformed. FIG. 13 is a diagram illustrating a state in which the luminous intensity distribution of the measurement light in the NA is deformed when the measurement light is diffracted in the arrow direction in the drawing. The component in the arrow direction (left and right direction on the paper surface) is relatively reduced by diffraction compared to the component perpendicular to the arrow (up and down direction on the paper surface).

  FIG. 14 is a diagram for explaining the cause of the measurement error of the position detection device 2 when astigmatism remains in the optical system constituting the position detection device 2. When the region of the pupil plane R is divided as shown in FIG. 14, the region A is a region in which the focus position is shifted in the plus direction, and the region B is a region in which the focus position is shifted in the minus direction. FIG. 15 is a diagram for explaining the cause of the measurement error of the position detection device 2 when spherical aberration remains in the optical system constituting the position detection device 2. When the region of the pupil plane R is divided as shown in FIG. 15, the region A is a region in which the focus position is shifted in the plus direction, and the region B is a region in which the focus position is shifted in the minus direction. FIG. 16 is a diagram for explaining the cause of the measurement error of the position detection device 2 when coma remains in the optical system constituting the position detection device 2. When the region of the pupil plane R is divided as shown in FIG. 16, the region A is a region where the focus position is shifted in the plus direction, and the region B is a region where the focus position is shifted in the minus direction.

  When the measurement light has a uniform light flux intensity distribution as shown in FIG. 12, it is not affected by each aberration of the optical system, but the measurement light has a light flux intensity distribution as shown in FIG. In this case, it is affected by each aberration of the optical system. That is, since the light beam passes through the region indicated by the chain line in FIGS. 14 and 15, the position detection device is more affected by shifting the focus position of the region B in the minus direction than by shifting the focus position of the region A in the plus direction. 2 causes a measurement error. Also in FIG. 16, when the light beam intensity distribution shifts due to the influence of the pattern of the reticle R and the object plane tilt, and the light beam passes through the region indicated by the chain line in FIG. The influence of shifting in the minus direction is more than the influence of shifting the focus position of the region A in the plus direction, and a measurement error by the position detection device 2 occurs.

  Therefore, it is necessary to correct spherical aberration by shifting a part (not shown) of lenses constituting the relay optical systems 40a to 40c described above in the optical axis direction. Further, it is necessary to correct the coma aberration by shifting a part of the lenses constituting the relay optical systems 40a to 40c in a direction orthogonal to the optical axis direction. As for astigmatism, a parallel plane plate (not shown) is installed in any one of the optical paths between the beam expander 28b and the relay optical systems 36a to 36c, and this parallel plane plate is used as the position detection device 2. Correction is performed by tilting the optical system of the optical system. In addition, each aberration of each optical system which comprises the position detection apparatus 2 can be measured using an interferometer etc.

  Further, in this position detection device 2, since the measurement light itself is scanned by rotating the galvanometer mirror 22, scan astigmatism is caused by scanning the measurement light. This scan astigmatism is also corrected by tilting the parallel plane plate described above. Further, a scan curve is generated due to a scan tilt residue in which a tilt component of the measurement light is applied by scanning the measurement light, a pattern edge on the reticle R, and an imaging point of the measurement light being different. The measurement error (offset amount) of the position detection device 2 due to the influence of the scan tilt residue and the scan curvature is obtained by using the position detection device 2 and a reticle mark plate RFM (FIG. 1 and FIG. 1) whose position is defined in advance as a reference plane. It can be measured by performing position detection (see FIG. 2). That is, the amount of deviation (offset amount) between the position based on the detection result of reticle mark plate RFM by position detection device 2 and the specified position of reticle mark plate RFM is calculated. By taking this calculated offset amount into account, it is possible to correct the scan tilt residue and the scan curve.

  Further, the pattern edge and fine pattern formed on the reticle R as described above, the aberration of the optical system constituting the position detection device 2, the diffraction of the measurement light, and the like, or the interaction thereof, are factors. In order to avoid measurement errors, the control device 56 performs an averaging process. For example, as shown in FIG. 17, when the pattern on the reticle R has line and space in the X direction and the Y direction, the light receiving sensor 46 is measured by scanning the measurement light in the arrow direction in the figure. The measurement result at each measurement point is output to the control device 56. For example, as shown in FIG. 17, it is assumed that the light receiving sensor 46 outputs the measurement results at the seven measurement points r11 to r17 to the control device 56.

  The control device (calculation means) 56 calculates the average value of the detection results of the position of the reticle R at the seven measurement points r11 to r17. The control device (comparison means) 56 compares the detection result of the position of the reticle R at the measurement point r11 with the calculated average value. The control device (discriminating means) 56 discriminates whether the detection result of the position of the reticle R at the measurement point r11 is correct based on the comparison result. That is, when the detection result of the position of the reticle R at the measurement point r11 is a value far from the average value, specifically, when a predetermined threshold value is exceeded, the position of the reticle R at the measurement point r11 is caused by a measurement error. It is determined that it was not detected correctly. When the detection result of the position of the reticle R at the measurement point r11 is close to the average value, specifically, when the predetermined threshold value is not exceeded, the position of the reticle R at the measurement point r11 is accurately detected. It is determined that Similarly to the measurement point r11, the detection result of the position of the reticle R at the other measurement points r12 to r17 is also compared with the average value to determine whether there is a measurement error.

  Further, as shown in FIG. 1, the projection exposure apparatus according to this embodiment is provided with an oblique incidence type multi-point focal position detection system (60a, 60b) comprising an irradiation system 60a and a light receiving system 60b. . The irradiation system 60a projects a plurality of slit images on the wafer W surface obliquely with respect to the optical axis AX, and the light receiving system 60b controls a detection signal corresponding to the lateral shift amount of the re-imaged slit images. 56. At the time of exposure, the control device 56 controls the Z stage 12 so that the wafer W surface is focused on the image plane of the projection optical system PL based on the detection result of the multipoint focal position detection system (60a, 60b). The position and inclination angle in the Z direction are controlled.

  In this projection exposure apparatus, it is necessary to optically align (align) the reticle (first surface) R and the wafer (second surface) W prior to exposure. A wafer mark (alignment mark) is formed on the wafer W. In order to detect the position of the wafer mark and thus detect the position of the wafer W, an illumination optical system for illuminating the wafer mark and imaging optics for condensing the light beam reflected by the wafer mark to form an image An off-axis alignment device ALG having a system is used.

  The alignment apparatus ALG according to this embodiment includes a light source (not shown) for emitting illumination light having a wide wavelength bandwidth. The illumination light emitted from the light source illuminates the wafer mark formed on the wafer W through an illumination optical system (not shown) for illuminating the wafer mark (second mark). The reflected light reflected by the wafer mark enters a CCD (not shown) via an imaging optical system (not shown) for forming a mark image based on the reflected light reflected by the wafer mark. . An image of an index mark (first mark) arranged in the illumination optical system and a wafer mark image are formed on the imaging surface of the CCD, and an output signal from the CCD is output to the control device 56. . The control device 56 performs alignment by moving the XY stage 13 based on the output signal from the alignment device ALG.

  According to the alignment apparatus ALG according to this embodiment, alignment is performed between the reticle R whose position has been detected by the position detection apparatus 2 and the wafer W whose position has been detected by the multipoint focal position detection system (60a, 60b). , Alignment can be performed more accurately.

  According to the position detection device according to this embodiment, since the relay optical system that guides the measurement light to different positions in the reticle is provided, a plurality of positions on the reticle surface can be detected, and a large area of the reticle surface can be detected. The position at can be accurately detected in a shorter time. Further, since the confocal optical system is provided, an apparatus having a compact and simple configuration can be provided. Therefore, it can be easily installed in the projection exposure apparatus, and the position of the reticle can be detected with high accuracy.

  In addition, the projection exposure apparatus according to this embodiment includes a position detection device that can detect the position of the reticle with high accuracy, so that an imaging error on the wafer due to the bending of the reticle or the like can be accurately detected. Can be detected. Therefore, the wafer can be exposed with high resolution.

  In the position detection apparatus according to this embodiment, the position of the reticle R, which is the test surface, is detected using the field stop 34 as a reference member as a reference surface. However, the reticle mark plate RFM is used as the reference surface. The position of R may be detected. That is, the position of the reticle mark plate RFM is detected in advance by the position detection device 2. Specifically, reticle stage RST is moved in the X direction so that reticle mark plate RFM is positioned at measurement points 42 a to 42 c of position detection device 2. Then, the position detection device 2 detects positions corresponding to the measurement points 42a to 42c of the reticle mark plate RFM. The control device 56 stores the detection result in a storage unit (not shown) or the like, and detects the position of the reticle R based on the detection result, that is, the position of the reticle mark plate RFM. In this case, it is not necessary to install the field stop 34, and the configuration of the position detection device 2 can be simplified.

  In the position detection apparatus according to this embodiment, the field stop as the reference member is disposed at a position optically conjugate with the focal position of the confocal optical system. You may arrange.

  Further, in the position detection apparatus according to this embodiment, the position detection is performed using the confocal microscope 14 shown in FIG. 4, but the position detection is performed using the confocal microscope 114 as shown in FIG. Also good. As shown in FIG. 18, the confocal microscope 114 has a configuration in which a focus adjustment lens 20 constituting the confocal microscope 14 is included in and integrated with the galvanometer mirror 22. When the confocal microscope 114 is used, the traveling direction of the measurement light is changed by shifting the collimator lens 26 in a direction orthogonal to the optical axis. That is, the collimator lens 26 functions as a selection unit for selectively guiding the measurement light to different positions in the reticle R plane and a scanning unit for scanning the measurement light. Similarly to the confocal microscope 14, position detection is performed by position information when the collimator lens 26 is driven in the optical axis direction (that is, position information of the focal position F of the confocal optical system) and the light receiving sensor 46. It is executed by processing the light quantity information of the received measurement light by the control device (detection means) 56.

  In this embodiment, a step-and-scan projection exposure apparatus is described as an example, but the present invention can also be applied to a step-and-repeat projection exposure apparatus.

  In the projection exposure apparatus according to the above-described embodiment, the reticle (mask) is illuminated by the illumination optical apparatus (illumination process), and the transfer pattern formed on the mask using the projection optical system is transferred to the photosensitive substrate (wafer). A micro device (a semiconductor element, an image sensor, a liquid crystal display element, a thin film magnetic head, etc.) can be manufactured by transferring (transfer process) to the substrate. FIG. 19 shows an example of a technique for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the projection exposure apparatus according to the above-described embodiment. This will be described with reference to a flowchart.

  First, in step S301 in FIG. 19, a metal film is deposited on one lot of wafers. In the next step S302, a photoresist is applied on the metal film on the wafer of the l lot. Thereafter, in step S303, using the projection exposure apparatus according to the above-described embodiment, the pattern image on the mask is sequentially exposed and transferred to each shot area on the wafer of one lot via the projection optical system. The Thereafter, in step S304, the photoresist on the one lot of wafers is developed, and in step S305, the resist pattern is etched on the one lot of wafers to form a pattern on the mask. Corresponding circuit patterns are formed in each shot area on each wafer.

  Thereafter, a device pattern such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer. According to the semiconductor device manufacturing method described above, since the exposure is performed using the projection exposure apparatus according to the above-described embodiment, a good semiconductor device can be obtained. In steps S301 to S305, a metal is vapor-deposited on the wafer, a resist is applied on the metal film, and exposure, development, and etching processes are performed. Prior to these processes, on the wafer. It is needless to say that after forming a silicon oxide film, a resist may be applied on the silicon oxide film, and steps such as exposure, development, and etching may be performed.

  In the projection exposure apparatus according to the above-described embodiment, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). . Hereinafter, an example of the technique at this time will be described with reference to the flowchart of FIG. In FIG. 20, in the pattern forming step S401, a so-called photolithography step is performed in which the mask pattern is transferred and exposed to a photosensitive substrate (such as a glass substrate coated with a resist) using the projection exposure apparatus according to the above-described embodiment. Executed. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate undergoes steps such as a developing step, an etching step, and a resist stripping step, whereby a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming step S402.

  Next, in the color filter forming step S402, a large number of groups of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three of R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning line direction. Then, after the color filter formation step S402, a cell assembly step S403 is executed. In the cell assembly step S403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step S401, the color filter obtained in the color filter formation step S402, and the like. In the cell assembly step S403, for example, liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern formation step S401 and the color filter obtained in the color filter formation step S402, and a liquid crystal panel (liquid crystal cell ).

  Thereafter, in a module assembly step S404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display element, since the exposure is performed using the projection exposure apparatus according to the above-described embodiment, a liquid crystal display element as a good micro device can be obtained.

It is a figure which shows schematic structure of the projection exposure apparatus concerning Embodiment. It is a figure which shows the structure of the reticle stage concerning embodiment, and its periphery part. It is a figure which shows the structure of the position detection apparatus concerning embodiment. It is a figure which shows the structure of the confocal microscope concerning embodiment. It is a figure for demonstrating the change of the advancing direction of measurement light when rotating a galvanometer mirror. It is a figure for demonstrating the change of the focus position of a collimator lens when a collimator lens is moved. It is a figure which shows the structure of the field stop concerning an embodiment. It is a figure which shows the example of the measurement point by the light receiving sensor at the time of scanning measurement light. It is a graph which shows a focus position and the position of the measurement light at that time. It is a figure which shows the positional relationship of the several measurement point and reticle surface by a position detection apparatus. It is a figure which shows the circular area | region (pupil) R of the measurement light in the numerical aperture (NA) of a confocal optical system. It is a figure for demonstrating the light beam intensity distribution of measurement light. It is a figure for demonstrating the deformation | transformation of the light beam intensity distribution of measurement light. It is a figure which shows the area | region which shifts a focus position in case the astigmatism remains in the optical system which comprises a position detection apparatus. It is a figure which shows the area | region which shifts a focus position in case the spherical aberration remains in the optical system which comprises a position detection apparatus. It is a figure which shows the area | region which shifts a focus position in case the coma aberration remains in the optical system which comprises a position detection apparatus. It is a figure which shows the example of the pattern on a reticle, and the example of the some measurement point by a light receiving sensor. It is a figure which shows the structure of another confocal microscope. It is a flowchart which shows the manufacturing method of the semiconductor device as a microdevice concerning embodiment of this invention. It is a flowchart which shows the manufacturing method of the liquid crystal display element as a microdevice concerning embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Surface plate, 2 ... Position detection apparatus, 12 ... Z stage, 13 ... XY stage, 14 ... Confocal microscope, 16 ... Light source unit, 18 ... Half mirror, 20 ... Focus adjustment lens, 22 ... Galvano mirror, 26 ... collimator lens, 28a, 28b ... beam expander, 30, 32 ... plane parallel plate, 34 ... field stop, 36a-36c, 42a-42c ... relay optical system, 44 ... pinhole, 46 ... light receiving sensor, 48a, 48c , 50a, 50c ... Field division mirror, 56 ... Control device, 60a, 60b ... Multi-point focus position detection system, ALG ... Alignment device, IL ... Illumination optical system, R ... Reticle, RST ... Reticle stage, PL ... Projection optical system , W ... wafer, WST ... wafer stage.

Claims (13)

A position detection device that irradiates a test surface with light and detects the position of the test surface based on light reflected by the test surface,
A first optical system that forms a first conjugate position optically conjugate with the test surface;
A confocal optical system that forms a second conjugate position optically conjugate with the test surface and the first conjugate position;
A reference member disposed at the first conjugate position;
A light receiving unit that includes a pinhole disposed at the second conjugate position, and that receives light via the confocal optical system and the pinhole;
A processing unit that calculates the position of the test surface based on light reception information of the light receiving unit,
The light receiving unit receives the first light reflected by the test surface and the second light reflected by the reference member, respectively.
The position detection device, wherein the processing unit calculates a position of the test surface based on light reception information of the first light and light reception information of the second light. A position detection device that irradiates a test surface with light and detects the position of the test surface based on light reflected by the test surface,
A first optical system that forms a first conjugate position optically conjugate with the test surface;
A second optical system that forms a second conjugate position optically conjugate with the test surface and the first conjugate position;
A confocal optical system that forms a third conjugate position optically conjugate with the test surface, the first conjugate position, and the second conjugate position;
A reference member disposed at the first conjugate position;
A light receiving unit that includes a pinhole disposed at the third conjugate position, and that receives light via the second optical system, the confocal optical system, and the pinhole;
A processing unit that calculates the position of the test surface based on light reception information of the light receiving unit,
The light receiving unit receives the first light reflected by the test surface and the second light reflected by the reference member, respectively.
The position detection device, wherein the processing unit calculates a position of the test surface based on light reception information of the first light and light reception information of the second light. The first optical system reduces light from the first conjugate position on the surface to be measured;
The position detection apparatus according to claim 2, wherein the second optical system expands light from the second conjugate position at the first conjugate position. The reference member has a predetermined reference pattern,
The light receiving unit receives the first light reflected by the test surface and passing through the reference pattern, and the second light reflected by a portion of the reference member different from the reference pattern. The position detection device according to any one of claims 1 to 3, wherein the position detection device is configured as described above. The position detection apparatus according to claim 4, wherein the reference pattern includes at least one slit. The reference pattern includes a plurality of slits arranged in parallel along the short direction,
The light receiving unit receives the plurality of first lights reflected by the test surface and respectively passing through the plurality of slits,
The position detection device according to claim 5, wherein the processing unit calculates a position of the test surface based on light reception information of the plurality of first lights corresponding to each of the plurality of slits. . Scanning means for scanning the reference pattern on the reference member with light applied to the test surface;
The light receiving unit includes the first light reflected by the test surface through the reference pattern among the light scanned by the scanning unit, and the first light reflected by a portion different from the reference pattern. The position detecting device according to claim 4, wherein the position detecting device receives each of the two lights. Scanning means for scanning the light irradiated to the test surface on the reference member in a direction having a predetermined angle with respect to the longitudinal direction of the slit;
The light receiving unit includes the first light reflected by the test surface through the slit among the light scanned by the scanning unit, and the second light reflected by a portion different from the slit. The position detecting device according to claim 5, wherein the position detecting device receives light respectively. The processor is
Calculation results of a plurality of different positions of the test surface calculated based on scanning by the scanning means.
An average value calculating means for calculating an average value of the fruit;
Comparison means for comparing each of the calculation results of a plurality of different positions on the test surface with the average value calculated by the average value calculation means,
Based on the comparison result by the comparison means, the correctness of the calculation result of the position of the test surface is determined.
Discriminating means,
The position detection device according to claim 7 or 8, further comprising: Comprising a selection means for selectively guiding the light irradiating the test surface to a plurality of different positions on the reference member;
10. The position detection device according to claim 1, wherein the light receiving unit receives the first light corresponding to each of the plurality of positions. 11. An alignment apparatus that performs alignment of the first surface and the second surface by detecting a first mark provided on the first surface and a second mark provided on the second surface,
Alignment apparatus comprising: a position detecting device according to any one of claims 1 to 10 for detecting a position of the first surface. In an exposure apparatus that exposes a mask pattern onto a photosensitive substrate,
Exposure apparatus comprising: a position detecting device according to any one of claims 1 to 10 for detecting the position of the surface of the mask. An exposure step of exposing a predetermined pattern on a photosensitive substrate using the exposure apparatus according to claim 12 ;
A developing step of developing the photosensitive substrate exposed by the exposing step;
A method for manufacturing a microdevice, comprising:

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