JP2017215219A - Measurement device, pattern formation device, and article manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measurement device capable of measuring a position of a side face of a substrate without deteriorating detection accuracy even if a shape of the side face of the substrate diversifies.SOLUTION: A measurement device 100 for measuring a position of a specimen 5 includes: a first detection optical system 110 for detecting first reflection light of light which enters at a first incident azimuth angle to the specimen 5; a second detection optical system for detecting second reflection light of light which enters at a second incident azimuth angle different from the first incident azimuth angle to the specimen 5; and a calculation part for measuring the position of the specimen 5 on the basis of a first signal corresponding to the first reflection light detected by the first detection optical system 110 or a second signal corresponding to the second reflection light detected by the second detection optical system.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a measuring device, a pattern forming device, and an article manufacturing method.

  In a photolithography process, which is one of the manufacturing processes of semiconductor elements and the like, an exposure apparatus that projects and exposes an image of a pattern formed on a mask onto a substrate such as a wafer or a glass plate coated with a photosensitive agent such as a photoresist. Is used. The alignment of the substrate in the exposure apparatus is executed using a plurality of sensors arranged on the stage on which the plate is mounted. This sensor measures the position of the side surface of the substrate with or without contact. In the case of the contact type, while the position of the side surface can be measured directly, the plate may be distorted by the stress at the time of contact. In recent years, non-contact sensors have attracted attention due to the thin plate and high precision of overlay. Patent Document 1 discloses a measurement method of illuminating two locations on a substrate side surface with light and measuring the distance between the two locations. Patent Document 2 discloses a pre-alignment apparatus that images the edge of a substrate at at least three reference positions set on a holder and measures positional information of the photosensitive substrate relative to the projection optical system based on the image information. doing.

JP 2001-241921 A JP-A-9-297408

  However, when the side surface position of the substrate is measured by a non-contact sensor using light, the measurement accuracy varies due to the effect of chamfering the side surface portion. For example, since a substrate mass-produced in the market has a thickness of 0.3 to 1.0 mm and a chamfering amount of 50 to several hundred μm, there is a high possibility that variations in detection results of the substrate side surface position will increase. In the future, as the substrate becomes thinner, the amount of chamfering is further reduced, and there is a concern that the accuracy of the non-contact type sensor is lowered.

  For example, an object of the present invention is to provide a measuring apparatus that can measure the position of the side surface of the substrate without degrading the detection accuracy even if the shape of the side surface of the substrate is diversified.

  In order to solve the above-described problem, a measurement device according to one aspect of the present invention is a measurement device that measures the position of a test object, and is a first measurement of light incident on the test object in a first incident direction. A first detection optical system for detecting the first reflected light, and a second detection optical for detecting the second reflected light of the light incident on the test object at a second incident direction different from the first incident direction. Based on the system and the first signal corresponding to the first reflected light detected by the first detection optical system, or the second signal corresponding to the second reflected light detected by the second detection optical system, A calculation unit that measures the position of the test object.

  According to the present invention, for example, it is possible to provide a measuring device that can measure the position of the substrate side surface without reducing the detection accuracy even if the shape of the substrate side surface is diversified.

It is the schematic of the structure of exposure apparatus. It is explanatory drawing of the measurement principle of the 1st detection optical system. It is explanatory drawing of the measurement principle of the 2nd detection optical system. It is explanatory drawing of the detection light beam azimuth | direction to the board | substrate side part in the 1st detection optical system 110 and the 2nd detection optical system 120. FIG. It is explanatory drawing of the amount of chamfering of a board | substrate. It is explanatory drawing of the signal waveform of the 1st detection optical system 110 and the 2nd detection optical system 120. FIG. It is explanatory drawing of the signal waveform of the 1st detection optical system 110 and the 2nd detection optical system 120. FIG. It is explanatory drawing when a light source and a collimation lens are made shared. It is explanatory drawing when a light source and a collimation lens are made shared. It is explanatory drawing when a light source and a collimation lens are made shared. It is explanatory drawing when a lens, a photodetector, and an arithmetic unit are made common. It is explanatory drawing when a measuring device is comprised in an exposure apparatus.

(First embodiment)
FIG. 1 is a view showing the arrangement of an exposure apparatus having a measuring apparatus for measuring the substrate side surface position. The exposure apparatus is an example of a lithography apparatus (pattern forming apparatus) that forms a pattern on a substrate. The original 1 is a so-called mask on which a pattern is projected, and is aligned and held with respect to the main body 2 by an alignment mechanism (not shown). The exposure illumination system 3 illuminates the original 1. The projection optical system 4 projects and images the pattern of the original 1 on the substrate 5. The substrate 5 is held on a substrate holding member 6 of a stage 7 that moves on an XY plane perpendicular to the optical axis of the projection optical system 4. The substrate holding member 6 has a chuck for adsorbing the substrate in a vacuum. The stage 7 is movable not only in the X and Y directions but also in the optical axis direction (Z direction) of the projection optical system 4 and serves as a drive system for focusing the substrate 5 and the original 1. The stage 7 is controlled to be driven in the Y direction by a laser interferometer 9 and a mirror 8 mounted on a part of the stage 7. Although not shown in the drawing in the X direction, the same configuration is adopted, and precise drive control is performed in the XY plane. A measurement apparatus (hereinafter referred to as a position measurement apparatus) 10 for measuring the substrate side surface position is added to the exposure apparatus including such a basic configuration. The position measuring device 100 is fixed to the substrate holding member 6, and a plurality of the position measuring devices 100 are arranged to measure the substrate position in the X, Y, and θ directions. The stage 7 is driven based not only on the measurement result of the laser interferometer 9 but also on the measurement result of the position measuring apparatus 100.

  The measurement principle of the position measurement apparatus 100 will be described with reference to FIGS. The position measurement apparatus 100 includes a first detection optical system 110 and a second detection optical system 120 that irradiate light from different directions and measure the side surface position of the substrate 5 that is a test object. Therefore, in the first detection optical system 110 and the second detection optical system 120, light is incident on the side surfaces (end portions) of the substrate 5 with different incident azimuths. The measurement principle of the first detection optical system 110 of the position measurement apparatus 100 will be described with reference to FIG. The first detection optical system 110 includes a light source 111, a collimation lens 112, a mirror 113, a lens 114, a lens 115, a photodetector 116, and a calculation unit 117. The light source 111 is a first illumination unit that emits light having a wavelength of about 500 to 1200 nm. The detection light beam 24 for detection emitted from the light source 111 is guided to the side surface portion of the substrate 5 through the collimation lens 112 and the mirror 113 which are first light guide portions. At this time, as shown in FIG. 4, the detection light beam 24 is guided in a direction orthogonal to the substrate side surface (+ Y direction). Therefore, the incident angle is in the vicinity of 90 degrees with respect to the side surface of the substrate 5. Then, the reflected light (first reflected light) scattered by the side surface portion of the substrate 5 is guided to the photodetector 116 which is the detection unit via the lens 114 and the lens 115 which are the first lens group. The The light detected by the photodetector 116 is recognized and recorded as a signal waveform having position information by the calculation unit 117. The first detection optical system is a dark field illumination / detection method.

  The measurement principle of the second detection optical system 120 of the position measurement apparatus 100 will be described with reference to FIG. The second detection optical system 120 includes a light source 121, a collimation lens 122, a lens 123, a lens 124, a photodetector 125, and a calculation unit 126. The light source 121 is a light source different from the light source 111 and is a second illumination unit that emits light having a wavelength of about 500 to 1200 nm. The detection light beam 25 for detection emitted from the light source 121 is guided to the side surface portion of the same substrate 5 as in FIG. 2 through the collimation lens 122 which is the second light guide portion. At this time, as shown in FIG. 4, the detection light beam 25 is guided in a direction parallel to the substrate side surface (+ X direction). Therefore, the incident angle is in the vicinity of 0 degree with respect to the side surface of the substrate 5. Then, the reflected light (second reflected light) regularly reflected by the side surface portion of the substrate 5 is guided to the photodetector 125 through the lens 123 and the lens 124 which are the second lens group. The light detected by the photodetector 125 is recognized and recorded as a signal waveform having position information by the arithmetic unit 126. Then, the position of the side surface of the substrate is determined from these recognized and recorded signal waveforms. The second detection optical system is a bright field illumination / detection system.

  Usually, the side surface of the substrate is subjected to chamfering processing such as round chamfering, such as R chamfering processing of about 50 to 1000 μm. The chamfering of the end surface (side surface) of the substrate is to process the end surface portion (side surface portion) into a curved surface in order to prevent damage to the substrate. The detection accuracy of the substrate side surface in the first detection optical system 110 and the second detection optical system 120 depends on the chamfering amount of the substrate side surface portion in a different manner. The amount of chamfering of the side surface portion of the substrate 5 will be described with reference to FIG. FIG. 5A shows a case where the chamfering amount is small. FIG. 5B is a diagram showing a case where the chamfering amount is large. L1 and L2 represent the chamfering amounts in the respective R chamfering processes.

  Next, the relationship between the first detection optical system 110 and the second detection optical system 120 and the chamfering amount when detecting the side surface portion of the substrate will be described. FIG. 6 is a diagram showing signal waveforms detected by each optical system when the chamfering amount on the side surface of the substrate is small, that is, in the case of FIG. The signal waveform of the first signal corresponding to the first reflected light detected by the first detection optical system 110 becomes a signal waveform A, and the first waveform corresponding to the second reflected light detected by the second detection optical system 120. The signal waveform of the second signal is a signal waveform B. The signal waveform A tends to decrease in intensity I as the chamfering amount decreases, and may be buried in other signals such as noise and cannot be detected. The signal waveform B tends to be less affected by the chamfering amount when the chamfering amount is reduced, and the accuracy of determining the side surface position is increased.

  FIG. 7 is a diagram showing signal waveforms detected by each optical system when the chamfering amount of the substrate side surface is large, that is, in the case of FIG. 5B. The signal waveform detected by the first detection optical system 110 is a signal waveform A, and the signal waveform detected by the second detection optical system 120 is a signal waveform B. The signal waveform A tends to increase in intensity I in proportion to the amount of chamfering, and is less affected by other signals such as noise. On the other hand, since the signal waveform B is easily affected by light refraction at the chamfered portion, a waveform shift (Y) occurs with respect to the true substrate side surface position, and the accuracy of determining the substrate side surface position is lowered.

  In view of the characteristics of the first detection optical system 110 and the second detection optical system 120 described above, when determining the substrate side surface position, the substrate side surface position is determined from the intensity of the signal waveform A or the detection position difference between the signal waveform A and the signal waveform B. A signal waveform (signal waveform A or signal waveform B) used to determine the signal is selected. At this time, the detection position of the signal waveform A is, for example, the peak position of the waveform. The detection position of the signal waveform B is, for example, a predetermined position in a region of 25% to 50% of the maximum intensity of the signal waveform. Note that the method for determining the detection position is not limited to this, and any method may be used as long as the signal position can be determined from the waveform, such as the center of gravity of the signal waveform.

  As shown in FIG. 6, when the intensity I of the signal waveform A is smaller than the threshold value Is, it is recognized that the chamfering amount of the side surface portion of the substrate is small and the detection accuracy of the first detection optical system 110 is low, and the second detection optics. The substrate side surface position is calculated from the signal waveform B detected by the photodetector 125 of the system 120. The threshold value Is at this time is a predetermined value that satisfies the required determination accuracy of the substrate side surface position. When the signal waveform intensity I is smaller than the threshold Is, it is assumed that the detection position difference Y between the signal waveform A and the signal waveform B is smaller than the threshold Ys related to the determination accuracy of the substrate side surface position.

  As shown in FIG. 7, when the detection position difference Y, which is a comparison result between the signal waveforms, is larger than the threshold value Ys, the chamfering amount of the side surface portion of the substrate is large, and the detection accuracy of the second detection optical system 120 is low. It is recognized. Therefore, the substrate side surface position is calculated from the signal waveform A detected by the photodetector 116 of the first detection optical system 110. The threshold value Ys at this time is a predetermined value that satisfies the required determination accuracy of the substrate side surface position. When the detection position difference Y is larger than the threshold Ys, the intensity I of the signal waveform A detected by the photodetector 116 of the first detection optical system 110 is larger than the threshold Is related to the determination accuracy of the substrate side surface position. Assuming that

  As described above, the signal waveform (signal waveform A or signal waveform B) used to determine the substrate side surface position from the intensity of the signal waveform A or the detection position difference between the signal waveform A and the signal waveform B can be determined. it can. When determining the signal waveform used to determine the substrate side surface position using the intensity of the signal waveform A, when the intensity I of the signal waveform A is smaller than the threshold Is, the photodetector 125 of the second detection optical system 120. The side surface position of the substrate is calculated from the signal waveform B detected in (1). On the other hand, when the intensity I of the signal waveform A is larger than the threshold Is, the substrate side surface position is calculated from the signal waveform A detected by the photodetector 116 of the first detection optical system 110. Further, when determining the signal waveform used for determining the substrate side surface position from the detection position difference between the signal waveform A and the signal waveform B, when the detection position difference Y between the respective signal waveforms is larger than the threshold value Ys, the first detection optical system The substrate side surface position is calculated from the signal waveform A detected by the 110 photodetector 116. On the other hand, when the detected position difference Y between the signal waveforms is smaller than the threshold Ys, the substrate side surface position is calculated from the signal waveform B detected by the photodetector 125 of the second detection optical system 120. Each of the threshold values Ys and threshold values Is can be set according to the specifications of the first detection optical system 110 and the second detection optical system 120 and the required accuracy of determining the substrate side surface position. When determining the substrate side surface position, a signal waveform for determining the substrate side surface position may be selected from information on the chamfering amount of the substrate obtained in advance (information on the shape of the side surface of the substrate).

  As shown in FIG. 8, a plurality of position measurement devices 100 including the first detection optical systems 110 and 2 are arranged on a substrate support member near the substrate side surface, and using these devices, the X position on each substrate side surface, Detect Y position. Further, the rotation amount around the Z axis is also calculated from the detection result. Based on the calculated result, the stage 7 is driven to correct the position of the substrate. The relationship between the position signals having information on the substrate side surface position recorded by the calculation units 117 and 23 is based on the signal position when the position of the substrate side surface where the position is determined in advance is detected.

  In the first detection optical system 110, the reflected (scattered) light from the side surface of the substrate is more chamfered as the chamfering amount is larger and the incident angle of light guided to the normal to the substrate side surface is larger. A lot of reflected (scattered) light is included. Here, the normal to the side surface of the substrate refers to the normal to the flat side surface of the substrate before chamfering. This leads to a decrease in detection accuracy of the substrate side surface position. Therefore, it is desirable that the incident angle of light guided to the normal line on the side surface of the substrate is 0 to 30 degrees. Further, in the second detection optical system 120, as the incident angle of the light guided to the normal line on the front and back surfaces of the substrate is larger, the rising of the waveform near the side surface of the substrate becomes steeper, and the intensity of the signal waveform increases. The accuracy of determining the substrate side surface position is improved. Therefore, it is desirable that the incident angle of the light guided to the normal line on the front and back surfaces of the substrate is larger. In addition, since the first detection optical system 110 and the second detection optical system 120 illuminate and detect the same side surface of the substrate, the photodetectors 116 and 22 may be line (one-dimensional) sensors.

  As described above, according to the present embodiment, it is possible to select which of the first detection optical system 110 and the second detection optical system 120 measures the position of the substrate side surface according to the chamfering amount of the substrate. Therefore, even if the chamfering amount of the substrate is diversified, the position of the side surface of the substrate can be measured without reducing the detection accuracy.

(Second Embodiment)
In the second embodiment, the light source 111 and the light source 121, the collimation lens 112, and the collimation lens 122 that are individually configured by the first detection optical system 110 and the second detection optical system 120 are shared. 9 shows the first detection optical system 110 when the light source 111 and the collimation lens 112 are shared with the second detection optical system 120, and FIG. 10 shows the light source 121 and the collimation lens 122 common with the first detection optical system 110. It is the figure which showed the 2nd detection optical system 120 at the time of becoming. FIG. 11 is an explanatory diagram of the incident direction of the detection light beam on the side surface of the substrate in the first detection optical systems 110 and 2. As shown in FIGS. 9 to 11, the light sources 111 and 121 and the collimation lenses 112 and 122 individually configured by the first detection optical system 110 and the second detection optical system 120 are the half mirrors 26 and 27, mirrors, respectively. 30 can be used in common. Specifically, as shown in FIG. 11, the light emitted from the light source 121 in the first detection optical system 110 is a collimation lens 122 that is a first light guide unit, the half mirror 26, the mirror 30, and the mirror 27. Then, the light is guided to the side surface of the substrate 5 via. In the second detection optical system 120, the light emitted from the light source 121, which is a common light source with the first detection optical system 110, passes through the side surface of the substrate 5 through the collimation lens 122, which is the second light guide unit, and the half mirror 26. The light is guided to the part. In this way, by sharing a part of the configuration of the first detection optical system 110 and the second detection optical system 120, the measurement apparatus can be reduced in size.

(Third embodiment)
In the third embodiment, the lens 114 and the lens 123, the lens 115 and the lens 124, the photodetector 116 and the photodetector 125, which are individually configured by the first detection optical system 110 and the second detection optical system 120, are calculated. The unit 117 and the calculation unit 126 are shared. FIG. 12 is a diagram showing the second detection optical system 120 in the present embodiment. Lenses 114 and 115, lenses 123 and 124, photodetectors 116 and 125, and arithmetic units 117 and 126, which are individually configured by the first detection optical system 110 and the second detection optical system 120, are mirror 28 and half mirror 29. Can be used in common. Specifically, as shown in FIG. 12, the light (first reflected light) reflected from the side surface portion in the first detection optical system 110 is a third light guide portion, a half mirror 29, a lens 123, The light is guided to the photodetector 125 through the lens 124. In addition, the light reflected from the side surface portion (second reflected light) in the second detection optical system 120 passes through the mirror 28, the half mirror 29, the lens 123, and the lens 124, which are the fourth light guide portion. The light is guided to a photodetector 125 which is a detection unit common to the one detection optical system 110. In addition, when using the said structural member in common in the position measuring apparatus 100, it is also possible to add the other optical member (a mirror, a light guide fiber, etc.) and to provide the drive part for driving the structural member containing them. . In this way, by sharing a part of the configuration of the first detection optical system 110 and the second detection optical system 120, the measurement apparatus can be reduced in size.

(Embodiment related to article manufacturing method)
The method for manufacturing an article according to the present embodiment is suitable for manufacturing an article such as a microdevice such as a semiconductor device or an element having a fine structure, for example. In the method for manufacturing an article according to the present embodiment, a latent image pattern is formed on the photosensitive agent applied to the substrate using the above-described exposure apparatus (a step of exposing the substrate), and the latent image pattern is formed in this step. Developing the substrate. Further, the manufacturing method includes other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, and the like). The method for manufacturing an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared with the conventional method.

As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.
The present invention is not limited to an exposure apparatus, and can also be applied to a pattern forming apparatus (lithography apparatus) such as a drawing apparatus or an imprint apparatus. Here, the drawing apparatus is a lithography apparatus that draws a substrate with a charged particle beam (electron beam, ion beam, etc.), and the imprint apparatus forms an imprint material (resin etc.) on the substrate by molding. Is a lithographic apparatus for forming a substrate on a substrate. The substrate is not limited to a Si wafer, and may be SiC (silicon carbide), sapphire, dopant Si, a glass substrate, or the like.

DESCRIPTION OF SYMBOLS 10 Position measuring device 17 Photo detector 18 Arithmetic device 22 Photo detector 23 Arithmetic device

Claims (11)

A measuring device for measuring the position of a test object,
A first detection optical system that detects a first reflected light of light incident on the test object in a first incident direction;
A second detection optical system for detecting a second reflected light of light incident on the test object at a second incident direction different from the first incident direction;
Based on the first signal corresponding to the first reflected light detected by the first detection optical system or the second signal corresponding to the second reflected light detected by the second detection optical system. And a calculation unit that measures the position of the test object.   The first reflected light is reflected light scattered on the side surface of the test object, and the second reflected light is reflected light regularly reflected on the side surface of the test object. The measuring device according to claim 1.   The calculation unit selects one of the first signal and the second signal based on the intensity of the first signal, and determines the position of the test object based on the selected signal. The measuring device according to claim 2, wherein the measuring device is obtained.   The arithmetic unit selects one of the first signal and the second signal based on a comparison result between the first signal and the second signal, and based on the selected signal The measuring apparatus according to claim 2, wherein the position of the test object is obtained.   The measurement apparatus according to claim 4, wherein the comparison result is a difference between a peak position or a gravity center position of the intensity of the first signal and a predetermined position of the waveform of the second signal.   The calculation unit selects one of the first signal and the second signal based on information on a shape of a side surface of the test object, and the test object based on the selected signal The measuring device according to claim 1, wherein the position of the measuring device is obtained. The measuring device is
A first illumination unit that emits light;
A first light guide part that guides light emitted from the first illumination part and makes it incident on a side surface of the test object in the first incident direction;
A first lens group for guiding the first reflected light to the first detection optical system;
A second illumination unit that emits light;
A second light guide part that guides light emitted from the second illumination part and makes it incident on the side surface of the test object in the second incident direction;
The measurement apparatus according to claim 1, further comprising: a second lens group that guides the second reflected light to the second detection optical system. The measuring device is
An illumination unit that emits light;
A first light guide part that guides light emitted from the illumination part and makes it incident on a side surface of the test object in the first incident direction;
A second light guide unit configured to guide light emitted from the illumination unit and to enter a side surface of the test object in the second incident direction;
A first lens group for guiding the first reflected light to the first detection optical system;
The measurement apparatus according to claim 1, further comprising: a second lens group that guides the second reflected light to the second detection optical system. The measuring device is
A first illumination unit that emits light;
A first light guide part that guides light emitted from the first illumination part and makes it incident on a side surface of the test object in the first incident direction;
A third light guide for guiding the first reflected light to the first detection optical system;
A second illumination unit that emits light;
A second light guide part that guides light emitted from the second illumination part and makes it incident on the side surface of the test object in the second incident direction;
The measurement apparatus according to claim 1, further comprising: a fourth light guide unit that guides the first reflected light to the second detection optical system. A pattern forming apparatus for forming a pattern on a substrate,
A measuring device according to any one of claims 1 to 9,
A substrate holding part for holding the substrate,
A pattern forming apparatus, wherein the measurement apparatus measures a position of a side surface of the substrate. Forming a pattern on a substrate using the pattern forming apparatus according to claim 10;
And a step of processing the substrate on which the pattern has been formed in the step.

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