JP2002305130A - Surface position detecting device, aligner and method of manufacturing microdevice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface position detecting device, which can detect the surface position of the surface of a substrate with high accuracy, by preventing the quantity of light used for a detection of the surface position from being reduced, even in the case where the angle of incidence of detecting light to the substrate is widely set for raising the detection accuracy of the detecting light. SOLUTION: In surface position detecting device, a light-sending side reflection type pattern plate 13 is provided with a reflective region and an antireflection region formed on the periphery of the reflective region, and arranged at a position conjugated with a surface WS of a wafer W, or in the vicinity of this position in an optical path, leading from a light source 11 to the surface WS of the wafer W. Light from the light source 11 is made to reflect at the reflective region to irradiate a prescribed shape of a pattern on the surface WS. Moreover, a light-receiving side reflection type pattern plate 20 is provided with a reflective region and an antireflection region formed on the periphery of the reflective region, and is arranged at a position optically conjugated with the surface WS, or in the vicinity of this position in an optical path, leading from the surface WS of the wafer W to a photoelectric conversion element 23. Light from the surface WS of the wafer W is made to reflect at the reflective region to lead the light to the element 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a surface position detecting device,
The present invention relates to an exposure apparatus and a method for manufacturing a micro device. In particular, when manufacturing a semiconductor device, a liquid crystal display device, an imaging device, a thin film magnetic head, and other micro devices by a lithography process, a surface of a substrate on which various micro devices are formed. The present invention relates to a surface position detection device that detects a position of a substrate surface in a direction perpendicular to a substrate, an exposure device including the surface position detection device, and a microdevice manufacturing method using the exposure device.

[0002]

2. Description of the Related Art Semiconductor devices, liquid crystal display devices, imaging devices,
In a photolithography process, which is one of the manufacturing processes of a thin-film magnetic head and other microdevices, a photosensitive agent such as a photoresist is applied to an image of a pattern formed on a mask or a reticle (hereinafter, collectively referred to as a mask). An exposure apparatus that transfers the data onto a wafer, a glass plate, or the like (hereinafter, these are collectively referred to as a substrate) is used. When development processing is performed on the substrate on which the image of the pattern formed on the mask has been transferred, a resist pattern corresponding to the transferred pattern is formed on the substrate. afterwards,
Various processes such as an etching process and a wiring forming process are performed on the substrate using the resist pattern formed on the substrate as a mask, and a process of forming a pattern corresponding to the mask pattern on the substrate is performed. The photosensitive agent is applied again on the upper surface of the substrate on which the pattern has been formed, and the above process is repeated several times to several tens of times.

As described above, in the photolithography process, an image of a pattern to be formed next is superimposed on a pattern already formed on a substrate and transferred.
Therefore, in order to manufacture a device having an intended function, the reticle and the substrate must be aligned with high accuracy. In recent years, patterns have been miniaturized for higher density, lower power consumption, and the like, and accordingly, a high alignment accuracy of, for example, about several tenths to several tenths of the minimum line width is required. .

In addition, as the pattern image formed on the mask is transferred onto the substrate via the projection optical system with the miniaturization of the pattern, the surface of the substrate is accurately aligned with the image plane of the projection optical system. Need to be included. For this purpose, the exposure apparatus includes a surface position detecting device for detecting position information of the substrate in the optical axis direction of the projection optical system. FIG. 14 is a side view showing a main part configuration of a conventional surface position detecting device and a main part configuration of an exposure apparatus related to the surface position detecting device. FIG. 15 is an optical system of the surface position detecting device shown in FIG. FIG. 3 is an optical path diagram showing that is telecentric on both sides. In addition, of the members shown in FIG.
The same members as those shown in FIG. 14 are denoted by the same reference numerals. In FIG. 14, reference numeral 100 denotes an illumination optical system that includes a light source such as an ArF excimer laser (wavelength: 193 nm) and emits illumination light IL that irradiates the reticle R.

[0005] A pattern of a micro device is formed on the reticle R. When illumination light IL emitted from the illumination optical system 100 is irradiated, an image of the pattern formed on the reticle R is projected on the projection optical system PL. Is transferred to the wafer W via The wafer W is held by suction on a wafer holder 101, and the wafer holder 101 is
Are supported at three support points 103a to 103c provided in the. The wafer stage 102 has an optical axis A of the projection optical system PL.
By tilting the support points 103a to 103c in the X direction by the same ratio to set the surface position of the wafer W, and by tilting the support points 103a to 103c independently of each other, tilting the surface of the wafer W with respect to the optical axis AX. (Leveling). A reference member 10 for determining a reference position of the wafer stage 102 is provided at one end of the wafer holder 101.
4 are provided.

Reference numeral 110 denotes a surface position detecting device,
An irradiation optical system 110a that irradiates the detection light DL from an oblique direction to the wafer W, and light obtained by irradiating the detection light DL to the wafer W is received and formed into an image on a photoelectric conversion element 123 such as a silicon photodiode. It has a light receiving optical system 110b and a detector 131 that detects the position of the surface of the wafer W in the optical axis AX direction based on the output signal of the photoelectric conversion element 123. The irradiation optical system 110a has a light source 111 that supplies white light having a wide wavelength range such as a halogen lamp. The light from the light source 111 is converted into a substantially parallel light beam by a condenser lens 112 and is incident on a deflection prism 113. . The deflection prism 113 deflects the substantially parallel light beam from the condenser lens 112 by refracting it.

On the exit surface of the deflecting prism 113, there is provided a light-transmitting-side pattern plate 113a composed of a stripe pattern extending in a direction perpendicular to the plane of the drawing. The light-transmitting-side pattern plate 113a is a transmission-type lattice pattern plate, and is arranged such that the lattice pattern forming surface on which the transmission portions and the light-shielding portions are alternately provided is on the wafer W side. The light transmitted through the light transmitting side pattern plate 113a passes through the condenser lens 114, the reflection plate 115, and the objective lens 116 in this order, and is detected from an oblique direction at an incident angle θ with respect to the optical axis AX of the projection optical system PL. Irradiation is performed on the surface of the wafer W as DL. The incident angle of the detection light DL is set to about 80 degrees. here,
As shown in FIG. 15, the optical system including the condenser lens 114 and the objective lens 116 is a so-called double-sided telecentric optical system, and is conjugate with the grating pattern forming surface of the light transmitting side pattern plate 113 a and the wafer W. The dots have the same magnification over the entire surface. Therefore, the light transmitting side pattern plate 113
Since the lattice pattern forming surface a of FIG. 14 has an equidistant lattice pattern with the longitudinal direction being the paper vertical direction in FIG. 14, the image formed on the surface of the wafer W A grid pattern is formed at regular intervals in the longitudinal direction.

Returning to FIG. 14, the detection light DL applied to the surface of the wafer W is reflected by the surface of the wafer W, passes through the objective lens 117, and then enters the vibration mirror 118. The vibrating mirror 118 is driven by a mirror driving system 132,
14 oscillates at a predetermined period T around an axis perpendicular to the paper surface of FIG. 14, and deflects the light passing through the objective lens 117 in the paper surface of FIG. 14. The light passing through the vibrating mirror 118 is incident on the light receiving side pattern plate 120 a formed on the incident surface of the tilt correction prism 120 via the condenser lens 119. The light-transmitting-side pattern plate 11 is provided on the light-receiving-side pattern plate 120a.
3a, a grating pattern similar to that of FIG. 3a is formed.
And forms an image on the photoelectric conversion element 123 via the relay lenses 121 and 122 in order. As shown in FIG. 15, the optical system including the objective lens 117 and the condenser lens 119 and the optical system including the relay lenses 121 and 122 are both-side telecentric optical systems.

Here, while the surface position detecting device having the above configuration is performing the detecting operation, the vibrating mirror 118 is moved to the position shown in FIG.
It vibrates at a period T in the middle paper. Vibrating mirror 11
The light reflected on the surface of the wafer W due to the vibration of the wafer 8 vibrates with respect to the lattice pattern formed on the light receiving side pattern plate 120a. Is a vibrating mirror 1
It changes in synchronization with the vibration of 18. Therefore, the photoelectric conversion element 123 outputs to the detection system 131 an AC signal whose intensity changes with the oscillation cycle of the oscillation mirror 118. Further, an AC signal having the same cycle and phase as the oscillation cycle T of the oscillation mirror 118 is output from the mirror drive system 132 to the detection system 131. The signal is synchronously detected, and a detection output signal is output to main control system 130. This detection output signal is called a so-called S-curve signal, and has a zero level when the surface of the wafer W is located on the imaging plane of the projection optical system PL.

When the surface of the wafer W is displaced from the image plane of the projection optical system PL, the light receiving side pattern plate 120a of the light condensed by the objective lens 117 and the condensing lens 119 is used.
Since the center of vibration with respect to the lattice pattern formed in the photoelectric conversion element 123 changes, the cycle of the AC signal output from the photoelectric conversion element 123 changes. Therefore, when the wafer W is located above the image plane of the projection optical system PL, the detection output signal has a positive level, and when the wafer W is located below the image plane, it has a negative level. Becomes The main control system 130 controls the level of the detection output signal output from the detection system 131,
A control signal is output to the stage drive system 133 to drive the three support points 103a to 103c of the wafer stage 102 to align the surface of the wafer W with the image plane of the projection optical system PL.

[0011]

By the way, the light transmitting side pattern plate 113a and the surface of the wafer W, the surface of the wafer W, and the light receiving side pattern plate 1 provided in the above-mentioned surface position detecting device.
The light receiving side pattern plate 120a and the photoelectric conversion element 123 are set to satisfy the Scheimpflug condition. Here, the conditions for Scheimpflug will be described. FIG. 16 is an explanatory diagram of Scheimpflug conditions. Now, consider the non-parallel A-plane and B-plane shown in FIG. With respect to the optical system that forms a pattern on the surface A on the surface B, the conditions that the surface A and the surface B satisfy the Scheimpflug condition are defined as the extension of the surface A in the meridional section of the optical system. If the intersection of the optical system with the object-side principal plane is H, and the intersection of the extension of the B-plane with the image-side principal plane of the optical system is H ', the distance L from the intersection H to the optical axis and the intersection Distance L 'from H' to optical axis
Means equal to

When the Scheimpflug condition is satisfied, a so-called tilt image relationship is established, and light emitted from any point on the A surface is focused on a corresponding point on the B surface. I do. Accordingly, an image of a point on the entire surface on the surface A is formed on the surface B. Therefore, the image of the pattern formed on the light transmitting side pattern plate 113a is accurately formed over the entire surface of the wafer W, and the image of the surface of the wafer W is accurately formed over the entire light receiving side pattern plate 120a. The image of the light receiving side pattern plate 120a is further
The image is accurately formed over the entire detection surface.

When the light-sending-side pattern plate 113 is arranged with respect to the wafer W so as to satisfy the Scheimpflug condition, the substantially parallel luminous flux from the condenser lens 112 is applied to the grating pattern formed on the light-sending-side pattern plate 113a. Prism 11 that refracts a substantially parallel light beam from the condenser lens 112 in order to irradiate the light with a substantially uniform illuminance distribution.
3 are provided. The light receiving side pattern plate 120a is arranged in the light receiving optical system 110b so as to satisfy the Scheimpflug condition with respect to the surface of the wafer W.
When this condition is satisfied, the incident angle of the light beam incident on the light receiving side pattern plate 120a becomes large. Light receiving side pattern plate 12
Although a configuration in which the photoelectric conversion element 123 is arranged near 0a is also possible, since the incident angle of the light beam is large, the photoelectric conversion element
There is a possibility that the amount of received light may significantly decrease due to vignetting of the incident light beam at 23. For this reason, the tilt correction prism 1 for deflecting the light flux transmitted through the light receiving side pattern plate 120a and guiding the light flux to the photoelectric conversion element 123 while preventing a decrease in the amount of received light.
20 are provided.

However, in the conventional surface position detecting device 110 shown in FIG. 14, since the incident angle φ1 of the light beam with respect to the exit surface of the deflecting prism 113 provided in the irradiation optical system 110a is large, it is almost parallel from the condenser lens 112. There is a problem that the reflectance with respect to the light flux becomes large (the transmittance becomes small) and the amount of the detection light DL decreases.
Further, since the incident angle φ2 of the light beam with respect to the incident surface of the tilt correction prism 120a provided in the light receiving optical system 110b is also large, the reflectance for the light beam condensed by the condenser lens 119 becomes large (the transmittance becomes small), and the final There is a problem that the amount of light incident on the photoelectric conversion element 123 becomes extremely small. For example, even if an anti-reflection film is formed on the exit surface of the deflecting prism 113 and the incident surface of the tilt correction prism 120, there is a light amount loss of 40 to 50%. Only the light amount of about 20% of the luminous flux
3 will be reached.

In recent years, the resolution of an exposure apparatus has been increased to meet the demand for miniaturization of a pattern of a micro device to be manufactured. As a method of increasing the resolution of the image of the pattern, a method of mainly shortening the wavelength of the illumination light IL emitted from the illumination optical system 100 and designing a high numerical aperture (NA) of the projection optical system PL. At present, there is a method for shortening the wavelength and the projection optical system PL.
The high resolution is achieved by both methods of increasing the numerical aperture of the optical disk. However, when the resolution is improved, the depth of focus of the projection optical system PL included in the exposure apparatus necessarily decreases. For example, if the numerical aperture of the projection optical system PL is increased to increase the resolution 1.5 times while keeping the wavelength of the illumination light IL the same, the depth of focus is reduced to 1 / 2.25. When the depth of focus of the projection optical system PL decreases, the optical axis A of the projection optical system PL decreases.
It is necessary to detect the surface of the wafer W in the X direction with higher accuracy and perform accurate alignment.

In order to increase the detection accuracy of the surface position detecting device 110, it is necessary to increase the incident angle θ of the detection light DL emitted from the irradiation optical system 110a shown in FIG. This is because when the amount of displacement of the wafer W in the optical axis AX direction from the image plane of the projection optical system PL is the same, the reflection when the wafer W is positioned on the image plane of the projection optical system PL This is because the deviation amount of the light from the optical path increases as the incident angle θ of the detection light DL increases. When the incident angle θ increases, the above-described Scheimpflug condition must be satisfied.
It is also necessary to increase the incident angle φ1 of the light beam with respect to the exit surface 13 and the incident angle φ2 of the light beam with respect to the incident surface of the tilt correction prism 120. When the incident angles φ1 and φ2 increase, the reflectance with respect to the incident light beam increases (transmittance decreases), so that the amount of light that can be received by the photoelectric conversion element 123 decreases.

Further, in the surface position detecting apparatus shown in FIG. 14, it is necessary to measure the irradiation position of the detection light DL on the wafer W when performing the adjustment at the time of manufacturing the exposure apparatus or performing the periodic adjustment. . When performing this measurement, the wafer holder 10
The reference member 104 provided at one end is used. The reference member 104 is provided with a glass plate in which a metal film having a high reflectance with respect to the detection light DL is partially formed, and the position of the glass plate surface is set to be substantially the same as the surface position of the wafer W. Have been. Then, by moving the reference member to a position near the position where the detection light DL is irradiated and scanning the wafer stage 102, the irradiation position of the detection light DL is determined based on a change in the amount of light received by the photoelectric conversion element 123. Measure. However, when the incident angle of the detection light DL increases, the difference between the reflectance of the metal film with respect to the detection light DL and the reflectance of the glass plate on which the metal film is not formed decreases, and the difference between the reflectance and the position where the detection light DL is irradiated The amount of light obtained by the photoelectric conversion element 123 and the detection light DL when the metal film is disposed
When the glass plate is placed at the position where is irradiated, the difference from the light amount obtained by the photoelectric conversion element 123 is reduced,
It is also difficult to measure the position of the detection light DL.

The present invention has been made in view of the above circumstances, and detects the surface position and the irradiation position of the detection light with high accuracy even when the incident angle of the detection light to the substrate is set to be large. It is a main object of the present invention to provide a surface position detecting device capable of performing such operations. In addition, the present invention prevents a decrease in the amount of light used for surface position detection even when the incident angle of the detection light to the substrate is set to be large in order to improve detection accuracy. It is an object of the present invention to provide a surface position detecting device capable of detecting a position. Further, the present invention includes a surface position detecting device capable of detecting the surface position of the substrate with high accuracy, and performs accurate substrate alignment based on the highly accurate surface position detection result of the surface position detecting device. Another object of the present invention is to provide an exposure apparatus suitable for forming a fine pattern on a substrate. Still another object of the present invention is to provide a method for manufacturing a micro device manufactured by forming a fine pattern using the above exposure apparatus.

[0019]

In order to solve the above-mentioned problems, a surface position detecting device according to a first aspect of the present invention is a device for detecting light from a light source (11) in an oblique direction with respect to a surface to be measured (WS). A light source (11) in the surface position detection device (10) for detecting the position of the test surface (WS) by guiding light from the test surface (WS) to the photoelectric conversion element (23). In the optical path from the light source to the test surface (WS) and the test surface (W
S) in at least one of the optical paths from the optical path from the photoelectric conversion element (23) to the photoelectric conversion element (23), and the test surface (W
S) and a reflective pattern plate (13, 20) disposed at or near a position optically conjugate with the reflective pattern plate (13, 20).
d, 52, 54a-54e) and the reflection area (40a-
40d, 52, 54a to 54e) and the antireflection regions (41, 44a to 44e, 50a to 50e,
53, 55). According to the present invention, the reflection type pattern plate including the reflection area and the antireflection area formed around the reflection area is provided in the optical path from the light source to the test surface, and is optically conjugate with the test surface. At a suitable position or in the vicinity of the position, the light from the light source is reflected only by the reflection area to irradiate the pattern with a predetermined shape on the surface to be inspected, or the reflection formed around the reflection area and the reflection area. A reflection type pattern plate having a prevention area is provided in the optical path from the surface to be measured to the photoelectric conversion element, and is disposed at a position optically conjugate with the surface to be measured or in the vicinity of the position, and the light from the surface to be measured is Is reflected only in the reflection region and guided to the photoelectric conversion element. In the present invention, when irradiating the light from the light source to the surface to be inspected as a pattern of a predetermined shape, the light from the light source is reflected by using the reflective pattern plate, so that the light from the light source is transmitted. The light amount loss can be suppressed as compared with the related art in which a predetermined pattern is irradiated on the surface to be inspected. In addition, of the light incident on the reflective pattern plate from the light source, the light reflected on the reflection area is guided to the surface to be inspected, and the light incident on the anti-reflection area is hardly guided on the surface to be inspected. This pattern can be applied to the surface to be inspected, which is suitable for improving the detection accuracy. Further, in the present invention, when the pattern irradiated on the surface to be inspected is re-imaged on the photoelectric conversion element, the image is re-imaged using the reflective pattern plate, so that light from the surface to be inspected is transmitted. Accordingly, the loss of light amount can be suppressed as compared with the related art in which re-imaging is performed on the photoelectric conversion element. Also, of the light incident on the reflective pattern plate from the test surface, the light reflected on the reflection region is guided to the test surface, and the light incident on the anti-reflection region is hardly guided on the test surface, When detecting the surface position of the surface to be detected by the principle of the photoelectric microscope, detection can be performed based on an optical signal having a high signal-to-noise ratio, which is suitable for improving detection accuracy. In the future, in order to improve the detection accuracy of the test surface, it is conceivable to further increase the incident angle of the irradiation light on the test surface. By providing the above-mentioned reflective pattern plate in the optical path from the light source to the test surface and in the optical path from the test surface to the photoelectric conversion element, light emitted from the light source to the test surface and photoelectric conversion from the test surface can be obtained. Since the loss of the light quantity of both the light reaching the element can be suppressed, the position of the test surface can be detected with high accuracy even if the incident angle of the irradiation light on the test surface is further increased. Further, the surface position detecting device according to the first aspect of the present invention is characterized in that the shapes of the reflection areas (40a to 40d, 52, 54a to 54e) of the reflection type pattern plates (13, 20) are constant. I have. According to this invention, since the shape of the reflective pattern plate does not change with time and is constant, the shape accuracy of the pattern irradiated on the surface to be detected or the shape accuracy of the pattern re-imaged on the photoelectric conversion element is improved. As a result, it is possible to contribute to improvement of the detection accuracy of the surface to be detected. Here, the reflective pattern plate (13) is provided within an irradiation optical system (10a) for irradiating the light from the light source (11) as detection light (DL) to the surface to be measured (WS) from an oblique direction. And the reflective pattern plate (20) is provided in a light receiving optical system (10b) for receiving light from the surface to be measured (WS) and forming an image on the photoelectric conversion element (23). It is characterized by.
Further, the surface position detecting device according to the first aspect of the present invention is configured such that the reflection area (4) of the reflection pattern plate (13, 20) is provided.
0a to 40d, 52, 54a to 54e) specularly reflect the incident light from the light source (11), and
S), or the surface to be inspected (W
S) is specularly reflected from the photoelectric conversion element (2).
It is characterized by being positioned so as to lead to 3). Further, the surface position detecting device according to the first aspect of the present invention includes the antireflection areas (44a to 44e, 50a to 50e).
e, 53) are the reflection areas (40a to 40d, 52)
Is formed only on the periphery of Also,
In the surface position detecting device according to the first aspect of the present invention, the anti-reflection area (41, 44a to 44e) has an uneven structure formed on the surface of the reflective pattern plate (13, 20). And diffracts or scatters the incident light. Further, the surface position detecting device according to the first aspect of the present invention is characterized in that the uneven shape is formed of multi-level binary optics that is approximated by a step shape formed by a plurality of planes. Further, the surface position detecting device according to the first aspect of the present invention includes the anti-reflection area (50a to 5a).
0e, 53) correspond to the reflection areas (40a to 40d, 5).
It has a concave portion formed around 2), and the concave portion blocks light traveling in the direction of the regular reflection after entering the concave portion. Further, the surface position detecting device according to the first aspect of the present invention includes the reflection type pattern plate (1).
3, 20) the reflection area (54a to 54e) includes a first reflection section, and the anti-reflection area (55) reflects the incident light in a direction different from that of the first reflection section. It is characterized by having a part. In addition, the first aspect of the present invention
The surface position detecting device according to the aspect of
To 40d, 52, 54a to 54e) are characterized in that a reflective film having a high reflectance to the incident light is formed. Further, in the surface position detecting device according to the first aspect of the present invention, the surface of the reflective pattern plate (13, 20) and the surface to be measured (WS) are connected to the irradiation optical system (10).
a) and at least one of the light receiving optical system (10b) is positioned so as to satisfy the Scheimpflug condition. The surface position detecting device according to the second aspect of the present invention converts the detection light (DL) into the surface to be detected (W
S) is illuminated obliquely to the surface position detection device (10) that receives reflected light from the surface (WS) to detect the position of the surface (WS). Surface (W
S) has a reflectance difference of 8% with respect to the detection light (DL) or the reflected light which is incident at an incident angle of 83 degrees or more.
A reference member (5) on which a reference pattern including the above-described first reflection portion (60) and second reflection portion (61) is formed, wherein the reference member (5) is an optical path of the detection light (DL). And at least one of the optical paths of the reflected light. According to the present invention, the reference member on which the reference pattern including the first reflection portion and the second reflection portion having the reflectance difference of 8% or more is formed is the optical path of the detection light and the optical path of the light reflected from the surface to be measured. At least one of the following. Therefore, when measuring the irradiation position of the detection light from the change in the amount of reflected light received when the reference member is scanned with respect to the detection light irradiated on the surface to be inspected at an incident angle of 83 degrees or more, the first The reflectance difference between the reflector and the second reflector is set to 8% or more, and the amount of light obtained when the detection light is applied to the first reflector and the amount of light obtained when the detection light is applied to the second reflector. Since a sufficient difference from the light amount can be obtained, the irradiation position of the detection light can be detected with high accuracy. The angle of incidence of the detection light on the surface to be inspected is expected to increase in the future in order to improve the detection accuracy of the surface position detecting device.
When the detection accuracy of the surface position detecting device is improved, the irradiation position of the detection light on the surface to be detected must be accurately measured. However, if measurement is performed using a reference member on which a conventional reference pattern is formed, a sufficient light amount difference cannot be obtained, and the irradiation position of the detection light cannot be measured with high accuracy. With the use of the position detection device according to the second aspect of the present invention, a reference pattern reference including a first reflection portion and a second reflection portion having a reflectance difference of 8% or more with respect to detection light incident at an incident angle of 83 degrees. Since it is provided on the member, the detection accuracy of the irradiation position of the detection light can be improved. Further, the surface position detecting device according to the second aspect of the present invention includes the first and second surface position detecting devices.
At least one of the reflection portions (60, 61) is characterized by being formed of a metal film or a dielectric multilayer film. Also, in the surface position detecting device according to the second aspect of the present invention, the second reflecting portion (61) has a concave-convex structure formed on a surface of the reference member (5). It is characterized in that the reflectance is reduced by diffracting or scattering. Further, in the surface position detecting device according to the second aspect of the present invention, the second reflecting portion (61) has a concave portion formed around the first reflecting portion (60),
The reflectance is reduced by blocking light that travels in the direction of regular reflection with respect to the reference member (5) after entering the concave portion. Further, the surface position detecting device according to the second aspect of the present invention is characterized in that the first and second reflecting portions (60, 61) are formed so as to reflect incident light in different directions. . Further, in the surface position detecting device according to the second aspect of the present invention, the first reflecting portion (60) is formed with a metal film or a dielectric multilayer film having a high reflectance with respect to incident light. It is characterized by. An exposure apparatus according to a first aspect of the present invention includes:
In an exposure apparatus for transferring a pattern formed on a mask (R) to a substrate (W), the position of a substrate stage (3) holding the substrate (W) and the position of a surface (WS) of the substrate (W) are determined by the The surface position detection device (10) that detects the position of the surface to be detected (WS), and the substrate (W) on the substrate stage (3) is detected based on the detection result of the surface position detection device (10). An adjustment device (3, 4a to 4c, 30, 33) for adjusting at least one of the position and the posture is provided. According to the present invention, there is provided a surface position detecting device capable of detecting the surface position of the substrate with high accuracy, and the position of the substrate is accurately adjusted based on the high-accuracy surface position detection result of the surface position detecting device. This is extremely suitable for forming a fine pattern on a substrate. An exposure apparatus according to a second aspect of the present invention includes:
The projection optical system (P) of the pattern formed on the mask (R)
In an exposure apparatus that transfers an image via the substrate (W) to the substrate (W), the detection light (DL) is irradiated obliquely to the surface (WS) of the substrate (W) via the irradiation optical system (10a). Then, the light from the surface (WS) of the substrate (W) is received by the light receiving optical system (10b) and the surface (WS) of the substrate (W) is received.
A surface position detection device (10) for detecting the position of the projection optical system, the numerical aperture NA of the projection optical system, and the surface position detection device (10).
Detection light (D) through the irradiation optical system (10a)
L) the incident angle θ on the surface (WS) of the substrate (W) and the numerical aperture NA1 of the light receiving optical system (10b) included in the surface position detection device (10) satisfy the following conditions, respectively. It is characterized by. NA ≧ 0.75 θ ≧ 83 degrees NA1 ≦ 0.1 As one method for improving the resolution of the projection optical system, there is a method of designing a numerical aperture of the projection optical system to be high. When designed, the depth of focus of the projection optical system PL becomes shallower. In particular, when the numerical aperture of the projection optical system is 0.75 or more, the depth of focus becomes extremely shallow, so that it is necessary to accurately detect and align the position of the substrate surface during exposure. In order to improve the detection accuracy of the surface position detecting device that detects the position of the substrate surface by irradiating the substrate surface with the detection light obliquely, it is necessary to increase the incident angle θ of the detection light with respect to the substrate surface. . Therefore, as described above, the incident angle θ of the irradiation optical system provided in the surface position detecting device is 8
It is set to three times or more. If the reflected light obtained by irradiating the substrate with the detection light has a light quantity distribution according to the reflection angle, the detection accuracy of the substrate surface is deteriorated. Therefore, the numerical aperture of the light receiving optical system included in the surface position detecting device is set to 0.1 or less in order to prevent an adverse effect on the detection accuracy of the light amount distribution of the reflected light. According to the present invention, there is provided a surface position detecting device capable of detecting the surface position of the substrate with high accuracy, and the position of the substrate is accurately adjusted based on the high-accuracy surface position detection result of the surface position detecting device. Is performed, and an image of the pattern formed on the mask can be transferred onto the substrate with high resolution, which is extremely suitable for forming a fine pattern on the substrate. In the exposure apparatus according to the second aspect of the present invention, as the surface position detection device (10), a position detection device (10) for detecting a position of a surface (WS) of the substrate (W) as a position of the test surface (WS). A surface position detecting device (10) according to a first aspect of the present invention is provided. The method for manufacturing a micro device according to the present invention includes: a position detecting step of detecting a position of a substrate (W) using a surface position detecting device (10) provided in the exposure apparatus; and a detection result of the position detecting step. A substrate adjusting step of adjusting at least one of a position and a posture of the substrate (W); and illumination light (IL).
Is applied to the mask (R) to transfer an image of a pattern formed on the mask (R) to the substrate (W), and the substrate (W) transferred in the transfer step is developed. And a developing step.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a surface position detecting apparatus, an exposure apparatus, and a method for manufacturing a micro device according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG.
1 is a side view illustrating a configuration of an exposure apparatus according to an embodiment of the present invention including a surface position detecting device according to an embodiment of the present invention. In the present embodiment, a reticle R as a mask
An example in which an image of a pattern formed on a wafer W is transferred to a wafer W as a substrate by a step-and-scan method will be described. In the following description, the XYZ rectangular coordinate system shown in FIG. 1 is set, and the positional relationship of each member will be described with reference to the XYZ rectangular coordinate system. The XYZ orthogonal coordinate system is set such that the X axis and the Y axis are parallel to the wafer stage 3 as the substrate stage, and the direction in which the Z axis is orthogonal to the wafer stage 3 (the optical axis AX of the projection optical system PL). (Parallel to direction). In the XYZ coordinate system in the figure, the XY plane is actually set to a plane parallel to the horizontal plane, and the Z axis is set vertically upward.

In FIG. 1, reference numeral 1 denotes a KrF excimer laser (wavelength: 248 nm) and an ArF excimer laser (wavelength:
193 nm), F ₂ laser (wavelength: 157 nm) and an illumination optical system having a light source, such as, shaping the light emitted from the light source, uniform illuminance distribution, setting the transmission wavelength, and the illuminance constant reticle The illumination light IL for irradiating R is emitted. The light source provided in the illumination optical system 1 is a g-line (436 nm) emitted from an extra-high pressure mercury lamp in addition to the above.
And i-line (365 nm), metal vapor laser light source, YAG
A pulse light source such as a laser harmonic generator can also be used.

A pattern of a micro device is formed on the reticle R. When illumination light IL emitted from the illumination optical system 1 is irradiated, an image of the pattern formed on the reticle R is projected on the projection optical system PL. Is transferred to the wafer W via The reticle R is held on a reticle stage (not shown), and is finely movable in the direction of the optical axis AX of the projection optical system PL.
Further, it is configured to be capable of two-dimensional movement and minute rotation in a plane perpendicular to the optical axis AX. The reticle stage is driven by a linear motor, and moves the reticle R in the X-axis direction in the figure in synchronization with the movement of the wafer stage 3. The position of the reticle stage in the XY plane is measured by a laser interferometer (not shown).

On the other hand, the wafer W is held by suction on the wafer holder 2, and the wafer holder 2 is supported by three support points 4 a to 4 c of the wafer stage 3. The wafer stage 3 projects and retracts the support points 4a to 4c by the same ratio in the direction of the optical axis AX of the projection optical system PL by the same ratio.
In addition to setting the position of S, the inclination (leveling) of the surface WS of the wafer W with respect to the optical axis AX is set by projecting and retracting the support points 4a to 4c independently of each other. The wafer stage 3 is driven by a linear motor similarly to the reticle stage, and can set the position of the wafer W arbitrarily in the XY plane, and can move the wafer W at a constant speed. XY of wafer stage 3
The position in the plane is measured by a laser interferometer (not shown). The outputs of the laser interferometer provided on the reticle stage and the laser interferometer provided on the wafer stage 3 are input to a main control system 30 described later, and the main control system 30 controls the reticle stage based on the measurement results of these laser interferometers. In addition to the control, a control signal is output to the stage drive system 33 to control the position of the wafer stage 3 in the XY plane. The wafer stage 3 and the supporting points 4a to 4a
c, the main control system 30, and the stage drive system 33 correspond to the adjusting device according to the present invention. A reference member 5 for determining a reference position of the wafer stage 3 is provided at one end of the wafer holder 2.
Is provided. The position of the upper surface of the reference member 5 is set to be substantially the same as the surface WS of the wafer W.

The projection optical system PL is provided with a lens controller (not shown) for controlling optical characteristics such as imaging characteristics to be constant in response to environmental changes such as temperature and atmospheric pressure. Further, the projection lens PL has an optical element such as a plurality of lenses, and the glass material of the optical element is selected from optical materials such as quartz and fluorite according to the wavelength of the illumination light IL. The magnification of the projection optical system PL may be not only a reduction system but also any one of an equal magnification and an enlargement system. However, the present embodiment is assumed to be a reduction system. Further, the projection optical system PL of the present embodiment is designed so that the image-side numerical aperture (the numerical aperture on the wafer W side) is 0.75 or more, preferably 0.77 or more, in order to improve the resolution.

Next, a surface position detecting device according to an embodiment of the present invention provided in an exposure apparatus according to an embodiment of the present invention will be described in detail. Surface position detecting device 10 of the present embodiment
Is an irradiation optical system 10a that irradiates the wafer W with the detection light DL from an oblique direction, and receives light obtained by irradiating the wafer W with the detection light DL, and converts the light into a photoelectric conversion element 23 such as a silicon photodiode. Receiving optical system 10b to form an image on
And a detector 31 that detects the position of the surface WS of the wafer W in the optical axis AX direction based on the output signal of the photoelectric conversion element 23. In the present embodiment, the surface WS of the wafer W corresponds to the test surface according to the present invention.

The illumination optical system 10a includes a light source 11 such as a halogen lamp for supplying white light having a wide wavelength range, a condenser lens 12 for converting the light from the light source 11 into a substantially parallel light beam, and a substantially parallel light beam from the condenser lens 12. A light-transmitting-side reflective pattern plate 1 as a reflective pattern plate that reflects light and shapes it into light having a predetermined shape pattern (for example, a lattice pattern)
3. A condenser lens 14 for condensing the light reflected on the light-transmitting-side reflective pattern plate 13, a reflector 15 for reflecting and deflecting the light condensed by the condenser lens 14, and reflecting on the reflector 15. The detected light is applied to the surface WS of the wafer W as the surface to be inspected.
It has an objective lens 16 for irradiating as L.

The detection light D passing through the irradiation optical system 10a
The incident angle θ of L to the surface WS of the wafer W is set to 83 degrees or more. The reason why the incident angle θ of the detection light DL with respect to the surface WS of the wafer W is increased as described above is to increase the detection accuracy of the surface position detection device 10. As described above, if the resolution is improved by increasing the numerical aperture of the projection optical system PL in order to miniaturize the pattern formed on the wafer W, the depth of focus of the projection optical system PL becomes shallower. In order to accurately arrange the surface WS of the wafer W within the depth of focus of the projection optical system PL, it is necessary to detect the surface WS of the wafer W with high accuracy. As described above, the incident angle of the detection light DL radiated from the irradiation optical system 10a to the surface WS of the wafer W from the irradiation optical system 10a is set to 83 degrees or more in order to improve the detection accuracy.

As can be seen by referring to the optical path indicated by the broken line in FIG. 1, the optical system composed of the condenser lens 14 and the objective lens 16 is a so-called double-sided telecentric optical system. In a state where the surface WS of the wafer W matches the image plane of the projection optical system PL, the pattern forming surface of the light-transmitting reflective pattern plate 13 is at or near a position optically conjugate with the surface WS of the wafer W. Placed in Therefore, the pattern forming surface of the light-transmitting-side reflective pattern plate 13 and the conjugate point on the wafer W have the same magnification over the entire surface. A reflection area and an anti-reflection area are formed on the pattern forming surface of the light-transmitting-side reflective pattern plate 13. The shape of the reflection area is constant without changing over time, and of the light incident on the light-transmitting side reflective pattern plate 13, the light incident on the reflection area is reflected, and the light incident on the anti-reflection area is reflected. Is prevented, the wafer W
The image formed on the surface WS reflects the shape of the reflection area. Also, as will be described in detail later, an evenly spaced lattice-like pattern whose longitudinal direction is the Y-axis direction in FIG. 1 is formed on the pattern forming surface of the light-transmitting-side reflective pattern plate 13. The image formed on the front surface WS of the wafer W is a grid pattern at regular intervals with the longitudinal direction in the Y-axis direction in FIG. As described above, since the shape of the reflection area formed on the pattern forming surface of the light-transmitting-side reflection-side pattern plate 13 is constant without changing over time, the image irradiated on the surface WS of the wafer W is not changed. Can be improved, and as a result, the detection accuracy of the surface WS of the wafer W can be improved.

Further, regarding the optical system composed of the condenser lens 14 and the objective lens 16, when the surface WS of the wafer W matches the image forming plane of the projection optical system PL, the wafer W
Is set so that the surface WS and the pattern forming surface of the light-transmitting-side reflective pattern plate 13 satisfy the Scheimpflug condition. Therefore, the image of the pattern formed on the light-transmitting-side reflective pattern plate 13 is accurately formed over the entire surface WS of the wafer W. FIG. 2 is a perspective view showing a state in which an image of a pattern formed on the light-transmitting-side reflective pattern plate 13 is formed over the entire surface WS of the wafer W. In FIG. 2, the circle with the reference symbol WS represents a part of the surface WS of the wafer W for convenience. Reference numeral DA denotes a detection area of the surface position detection device 10. In the example shown in FIG. 2, the longitudinal direction is set to the X-axis direction, and the shape is a rectangular shape. When the detection light DL is applied to the front surface WS of the wafer W via the objective optical system 16 provided in the irradiation optical system 10a, the detection light DL is formed on the pattern forming surface of the light-transmitting reflective pattern plate 13 in the detection area DA. Images SL1 to SL5 of different patterns
Is imaged. In the example shown in FIG. 2, the image SL3 is formed substantially at the center of the detection area DA, and the images S3 are formed at the four corners of the detection area DA.
L1, SL2, SL4 and SL5 are imaged, respectively.

Returning to FIG. 1, the light receiving optical system 10b includes an objective lens 17 which receives the reflected light from the wafer W and converts the reflected light received by the objective lens 17 into a substantially parallel light beam. A vibrating mirror 18 vibrating with respect to 20, a condensing lens 19 for condensing light passing through the vibrating mirror 18, a pattern of a predetermined shape including a reflection area and an anti-reflection area are formed, and the light passing through the condensing lens 19 is formed. Of which
A light-receiving-side reflective pattern plate 20 that reflects light incident on the reflective area, a relay lens 21 that forms an image of the light reflected by the light-receiving-side reflective pattern plate 20 on a photoelectric conversion element 23,
22.

The object side numerical aperture (the numerical aperture on the wafer W side) of the light receiving optical system 10b is 0.1 or less, preferably 0.05.
It is designed below. FIG. 3 is a diagram for explaining the reason why the object-side numerical aperture of the light receiving optical system 10b is designed to be small. As shown in FIG. 3, the detection light DL is applied to the surface WS of the wafer W via the objective lens 16 of the irradiation optical system 10a.
Is reflected, the reflected light obtained from the surface WS of the wafer W has a relative light amount distribution denoted by reference numeral PF in the figure. This light amount distribution PF is based on the optical axis AX1 of the light receiving optical system 10b.
When the pattern plate 20 deviates from the conjugate position, the detection result of the detection system 31 has an error according to the light amount distribution PF of the reflected light. In the example shown in FIG. 3, if the light quantity distribution of the reflected light is symmetric with respect to the optical axis AX1, the reflected light on the surface WS of the wafer W is detected as being reflected in the direction of the optical axis AX1, Although the position of the original surface WS of the wafer W is detected,
The light amount distribution PF in the figure is detected as if it is reflected in the direction indicated by the symbol LP. If the pattern plate 20 is displaced from the conjugate position, the surface WS
Is detected at the wrong position. Therefore, in the present embodiment, the object-side numerical aperture NA1 of the light receiving optical system 10b is set to 0.1.
The detection error of the surface WS of the wafer W due to the light quantity distribution of the reflected light is eliminated as much as possible by suppressing the influence of the light quantity distribution according to the reflection angle of the reflected light by designing the light quantity to be 0.05 or less, preferably. I have.

Returning to FIG. 1, the reflected light received by the objective lens 17 provided in the light receiving optical system 10b is converted into substantially parallel light and enters the vibrating mirror 18. The oscillating mirror 18 is driven by a mirror driving system 32 described later, oscillates at a period T around an axis parallel to the Y axis in FIG. To deflect. In this embodiment, the oscillating mirror 18 is disposed substantially on the pupil plane (Fourier transform plane) between the objective lens 17 and the condenser lens 19. What is necessary is just to be in the optical path with the conversion element 13.

The light passing through the vibrating mirror 18 passes through the condenser lens 19 and reaches the pattern forming surface of the light-receiving-side reflective pattern plate 20. On the pattern forming surface of the light-receiving-side reflective pattern plate 13 provided in the light-receiving optical system 10b, a reflection area and an anti-reflection area similar to those of the light-transmitting-side reflective pattern plate 13 are formed. Further, the shape of the reflection area is constant without changing over time, and of the light incident on the light-receiving side reflective pattern plate 20, the light incident on the reflection area is reflected, and the light incident on the anti-reflection area is reflected. Reflection is prevented. As described above, since the shape of the reflection area formed on the pattern forming surface of the light receiving side reflection side pattern plate 20 does not change over time and is constant, the shape of the image formed on the photoelectric conversion element 23 is formed. Accuracy can be improved, and as a result, it can contribute to improvement in detection accuracy of the surface WS of the wafer W.

Regarding the optical system composed of the objective lens 17 and the condenser lens 19, when the surface WS of the wafer W coincides with the image forming plane of the projection optical system PL, the light receiving side reflection type pattern plate The pattern forming surface 20 and the surface WS of the wafer W are set so as to satisfy the Scheimpflug condition. Therefore, in a state where the surface WS of the wafer W is coincident with the image forming plane of the projection optical system PL, the image SL1 to SL5 of the pattern on the surface WS of the wafer W (over the entire surface of the light-receiving reflective pattern plate 20). 2 (see FIG. 2).

As can be seen by referring to the optical path indicated by the broken line in FIG. 1, the optical system composed of the objective lens 17 and the condenser lens 19 is a double-sided telecentric optical system. In a state where the surface WS of the wafer W is coincident with the image plane of the projection optical system PL, the pattern forming surface of the light-receiving side reflective pattern plate 20 is located at or near a position optically conjugate with the surface WS of the wafer W. Be placed. Therefore, each point on the wafer W and the conjugate point of the light-receiving side reflective pattern plate 20 are the same magnification over the entire surface. Therefore, in a state where the surface WS of the wafer W coincides with the image forming plane of the projection optical system PL, the pattern forming surface of the light receiving side reflection side pattern plate 20 is shown in FIG. Further images of the images SL1 to SL5 are reprojected.

That is, the surface position detecting device 10 of this embodiment
In the state where the surface WS of the wafer W matches the imaging plane of the projection optical system PL,
The pattern formation surface, the surface WS of the wafer W, and the pattern formation surface of the light-receiving-side reflection-side pattern plate 20 have a relationship satisfying the Scheimpflug condition, and each surface has the same magnification over the entire surface. The pattern forming surface of the light-transmitting reflective pattern plate 13, the surface WS of the wafer W, and the pattern forming surface of the light-receiving reflective pattern plate 20 may all be arranged so as to satisfy the Scheimpflug condition. It is preferable that only one of the pattern forming surface of the light-transmitting reflective pattern plate 13 and the surface WS of the wafer W, and the surface WS of the wafer W and the pattern forming surface of the light-receiving reflective pattern plate 20 be Scheimpflug. They may be arranged so as to satisfy the conditions.

The light reflected by the light-receiving-side reflective pattern plate 20 forms an image on the photoelectric conversion element 23 via the relay lenses 21 and 22 in order. The relay lenses 21 and 22 are both-side telecentric optical systems as shown in FIG. 1, and form a further conjugate image of the image formed on the pattern forming surface of the light-receiving-side reflective pattern plate 20 on the photoelectric conversion element 23. I do.
It is preferable that the pattern forming surface of the light-receiving side reflective pattern plate 20 and the photoelectric conversion element 23 are arranged so as to satisfy the Scheimpflug condition with respect to the relay lenses 21 and 22.

Here, while the surface position detecting device having the above configuration is performing the detecting operation, the oscillating mirror 18 vibrates at a period T in the ZX plane by the driving of the mirror control system 32. The light reflected on the surface WS of the wafer W by the vibration of the vibrating mirror 18 is reflected by the light-receiving-side reflective pattern plate 2.
Since it vibrates with respect to the pattern formed at 0, the amount of light reflected by the pattern (reflection area) formed on the light-receiving-side reflective pattern plate 20 changes in synchronization with the vibration of the vibrating mirror 18. Therefore, the photoelectric conversion element 23 outputs to the detection system 31 an AC signal whose intensity changes with the oscillation cycle of the oscillation mirror 18. The mirror drive system 32 outputs an AC signal having the same cycle and phase as the oscillation cycle T of the oscillation mirror 18 to the detection system 31, and the detection unit 31 synchronizes these AC signals according to the principle of a so-called photoelectric microscope. Detection is performed and a detection output signal is output to the main control system 30. This detection output signal is
This is called a so-called S-curve signal, and becomes zero level when the surface WS of the wafer W is located on the image forming plane of the projection optical system PL.

When the surface WS of the wafer W is displaced from the image forming plane of the projection optical system PL, the light-receiving-side reflective pattern plate 2 for the light condensed by the objective lens 17 and the condensing lens 19 is used.
Since the vibration position with respect to the pattern formed at 0 changes, the period of the AC signal output from the photoelectric conversion element 23 changes. Therefore, when the wafer W is located above the image plane of the projection optical system PL, the detection output signal has a positive level, and when the wafer W is located below the image plane, it has a negative level. Becomes The main control system 30 outputs a control signal to the stage drive system 33 according to the level of the detection output signal output from the detection system 31 to drive the three support points 4 a to 43 c of the wafer stage 3. The surface WS of the wafer W is aligned with the image plane of the projection optical system PL.
It should be noted that the surface position detection device 10 of the present embodiment has a detection area DA
The plurality of images SL1, SL2, SL4, and SL5 are projected onto the inside and the positions of the surface WS of the wafer W are detected using these images. Therefore, the positions at a plurality of points on the wafer can be detected. The attitude of the surface WS of the wafer W (such as the inclination with respect to the optical axis AX) can also be detected.

The overall configuration of the exposure apparatus according to the embodiment of the present invention and the surface position detecting apparatus according to the embodiment of the present invention has been described. Light-side reflective pattern plate 1
3 and the specific configuration of the light-receiving side reflective pattern plate 20 will be described in detail.

[First Configuration Example of Reflective Pattern Plate] FIG. 4
3A is a diagram showing a first configuration example of a light-transmitting-side reflective pattern plate 13 and a light-receiving-side reflective pattern plate 20, FIG. 4A is a front view of a pattern forming surface, and FIG. A-A
FIG. 3 is a cross-sectional view taken along a line. The light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 are formed by processing a glass substrate, for example, and as shown in FIG. Regions 40a to 40
e and the antireflection region 41 are formed. Reflection area 4
4a are arranged in a lattice pattern on the pattern forming surface as shown in FIG. 4A, and the reflection areas 4a formed on the pattern forming surface of the light-transmitting reflective pattern plate 13 are formed.
The light reflected at 0a-40e is the condensing lens 1 in FIG.
4, the reflectors 15 and the objective optical system 16 sequentially pass the images SL1 to SL5 shown in FIG.
Projected to S. The anti-reflection area 41 includes a reflection area 40a.
It is formed over the entire surface of the pattern forming surface other than ４０40e. The reflection areas 40a to 40e are used without processing the flat surface of the above glass substrate as it is, and the antireflection area 41 has a fine irregular shape on the surface of the glass substrate as shown in FIG. It is a structure formed. FIG.
In the example shown in (b), a saw-tooth structure is formed as a fine uneven shape.

In FIG. 4B, the arrow L1 indicates the light incident on the light-transmitting-side reflective pattern plate 13 or the light-receiving-side reflective pattern plate 20. The incident light L1 is emitted from the light source 11 with respect to the light-transmitting-side reflective pattern plate 13 and is equivalent to light that has been made substantially parallel by the condenser lens 12. Corresponding to the light incident through the light source. The incident light L1 is obliquely incident on the pattern forming surface of the light-transmitting-side reflective pattern plate 13 or the light-receiving-side reflective pattern plate 20. The reflection areas 40a to 40e formed on the pattern forming surface of the light-transmitting-side reflective pattern plate 13 reflect the incident light L1 regularly, and the reflected lights R1 and R2 are focused on the condenser lens 14, the reflection plate 15, and the objective lens. The wafer 16 is positioned so as to be guided to the surface WS of the wafer W by the wafer 16. On the other hand, the reflection region 4 formed on the pattern forming surface of the light receiving side reflection type pattern plate 20
0a to 40e are reflected by the surface WS of the wafer W, specularly reflect light passing through the objective optical system 17, the vibrating mirror 18, and the condenser lens 19, and the photoelectric conversion element 23 through the relay lenses 21 and 22. It is positioned to lead to.

The antireflection area 41 formed on the light-transmitting-side reflective pattern plate 13 or the light-receiving-side reflective pattern plate 20 diffracts or scatters the incident light L1 so that the light does not travel in the direction in which the reflected lights R1 and R2 travel. Works like that. It is assumed that the entire surface (pattern forming surface) of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 covers the reflection regions 40a to 40a.
If it is flat like e, the incident light L1 will be specularly reflected over the entire surface. However, since the anti-reflection area 41 is formed in a portion other than the reflection areas 40a to 40e formed on the pattern forming surface, the light incident on the anti-reflection areas 40a to 40e is reflected light R1, R
There is almost no reflection in the 2 direction. In FIG. 4B, hatched portions indicate portions where there is almost no light traveling in the direction in which the reflected lights R1 and R2 reflected by the reflection regions 40d and 40e travel.

The reflection areas 40a to 40e reflect the incident light L1 with the reflectance of the surface of the glass substrate with respect to the light incident obliquely.
There is hardly any light in the direction in which 1,2 travels. Therefore, by using the light-transmitting-side reflective pattern plate 13 shown in FIG. The contrast of the images SL1 to SL5 to be obtained can be increased. Also, the light receiving side reflection type pattern plate 2
0 is the reflection area 40a of the light incident on the pattern formation surface.
-40e is specularly reflected with high reflectivity,
Since the light incident on the anti-reflection area 41 is hardly reflected to the light in which the specularly reflected light travels, a further conjugate image of the image formed on the pattern forming surface of the light-receiving side reflective pattern plate 20 can be formed with high contrast. It can be formed on the conversion element 23. As a result, the surface W of the wafer W can be accurately detected without deteriorating the detection accuracy due to stray light or the like.
The position of S in the optical axis AX direction can be detected.

Generally, as the incident angle of the incident light L1 increases, the reflectance in the reflection regions 40a to 40e increases. As described above, the light-transmitting-side reflective pattern plate 13
And the surface WS of the wafer W, and the surface WS of the wafer W and the pattern forming surface of the light-receiving side reflective pattern plate 20 are arranged so as to satisfy the Scheimpflug condition. The incident angle of the incident light L1 with respect to the pattern forming surfaces of the mold pattern plate 13 and the light receiving side reflection type pattern plate 20 also increases. Therefore, as described above, a relatively high reflectance can be obtained even if the reflection regions 40a to 40e are formed without using the flat surface of the glass substrate as it is, but the reflectance for the incident light L1 is reduced. In order to further increase the thickness, it is preferable to form a metal film, a dielectric multilayer film, and other high reflection films in the reflection regions 40a to 40e.

[Second Configuration Example of Reflective Pattern Plate] FIG.
3A and 3B are diagrams illustrating a second configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20, where FIG. 4A is a front view of a pattern forming surface, and FIG. BB
FIG. 3 is a cross-sectional view taken along a line. The light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 according to the second configuration example shown in FIG. The difference from the pattern pattern plate 20 is that the reflection area and the anti-reflection area are inverted. That is, the reflection areas 40a to 40e formed on the pattern surfaces of the light transmission side reflection pattern plate 13 and the light reception side reflection pattern plate 20 shown in FIG. The antireflection area 41 is a reflection area 43 that is used without processing the flat surface of the glass substrate as it is. In addition, as shown in FIG.
The fine concavo-convex shape formed at 42e is a saw-tooth structure, as in the first configuration example. In this configuration example as well, it is preferable to form a metal film, a dielectric multilayer film, and other high-reflection films in the reflection region 43 to increase the reflectance of the reflection region 43 with respect to the incident light L1.

The light-transmitting-side reflective pattern plate 13 having the above configuration
When the incident light L1 is obliquely incident on the pattern forming surface of the light-receiving-side reflective pattern plate 20, the reflected light R3, R4, and R5 specularly reflected by the reflection region 43 are obtained. Is reflected light R3, R4, R5
Is hardly obtained in the direction of travel. Therefore,
When the light-sending-side reflective pattern plate 13 according to the first configuration example is used, the light intensity of the images SL1 to SL5 in FIG. Is used, the light intensity of the images SL1 to SL5 is lower than the surroundings. That is, when the light-transmitting-side reflective pattern plate 13 according to the second configuration example shown in FIG. 5 is used, the images SL1 to SL5 projected on the surface WS of the wafer W are according to the first configuration example shown in FIG. Image SL1 projected on front surface WS of wafer W when light-transmitting-side reflective pattern plate 13 is used
ＳＬSL5 are inverted.

[Third Configuration Example of Reflective Pattern Plate] FIG. 6
3A and 3B are diagrams showing a third configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20; FIG. C-C
FIG. 3 is a cross-sectional view taken along a line. The light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 according to the third configuration example shown in FIG. 6 are different from the light-transmitting-side reflective pattern plate 13 and the light-receiving side reflection plate according to the first configuration example shown in FIG. The difference from the pattern pattern plate 20 is that the antireflection region 41 is formed over the entire pattern formation surface other than the reflection regions 40a to 40e in the first configuration example, whereas in the present embodiment, each of the reflection regions 40a to 40e is formed. 4
The point is that the anti-reflection area is formed only around 0e. In the example shown in FIG. 6A, the reflection areas 40a to 40e
, Rectangular antireflection regions 44a to 44e are respectively formed. The area 45 other than the reflection areas 40a to 40e and the antireflection areas 44a to 44e is, for example, a flat glass substrate surface that has not been processed. In addition, it is preferable to form a metal film, a dielectric multilayer film, and other high reflection films on the reflection regions 40a to 40e to increase the reflectance of the reflection regions 40a to 40e with respect to the incident light L1.

In order for the surface position detecting device 10 of the present embodiment to detect the position of the surface of the wafer W in the direction of the optical axis AX of the projection optical system PL, the images SL1 to SL5 projected on the surface WS of the wafer W are required. When the positions of the images SL1 to SL5 re-imaged on the pattern forming surface of the light-receiving side reflective pattern plate 20 are vibrated by the vibrating mirror 18, the reflection areas 40a to 40e
Is specularly reflected, and the reflection areas 40a-40
It is necessary to prevent specular reflection of light incident on portions other than e. Images SL1 projected on surface WS of wafer W
In order to increase the contrast of the SL5 with respect to the periphery, the reflection areas 40a to 4a of the light transmission side reflection type slit plate 13 are required.
0e anti-reflection regions 50a-50 formed around each
What is necessary is just to set suitably according to the contrast which seeks the width of e. The anti-reflection area formed around the reflection areas 40a to 40e of the light-receiving side reflection slit plate 20 has a width in which the image to be re-imaged moves by the vibrating mirror 18, and a surface WS of the wafer W whose optical axis AX What is necessary is just to set according to the range which moves to a direction (surface position detection range).

In this configuration example, of the incident light L1 incident on the pattern forming surface, the light incident on the area 45 and the reflection area 4
Light incident on 0a to 40e is specularly reflected. FIG. 6 (b)
In the example shown in FIG. 7, the reflected light R6, R8, R10
And the reflected light that has been specularly reflected upon the reflected light R7, R
Reference numeral 9 denotes reflected light that enters the reflection areas 40d and 40e and is specularly reflected. When the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 according to the present embodiment are provided in the irradiation optical system 10a and the light-receiving optical system 10b, respectively,
Not only the light reflected by the reflection areas 40a to 40e but also the light reflected by the area 45 enters the photoelectric detector 23. Only a light receiving surface may be provided, or a light blocking member for blocking light reflected by the region 45 may be provided on the incident surface of the photoelectric detector 23.

In the first to third configuration examples described above, the case where the fine irregularities formed in the antireflection regions 41, 42a to 42e, and 44a to 44e have a saw-tooth structure has been described as an example. . However, the uneven shape is not limited to the sawtooth shape, and the antireflection regions 41 and 42 are not limited to the sawtooth shape.
The shape is particularly limited as long as it can effectively diffract or scatter incident light to a to 42e and 44a to 44e so that there is almost no light reflected in the direction in which the reflected lights R1 to R10 travel. There is no. In addition, the anti-reflection area 41,
The fine patterns formed on 42a to 42e and 44a to 44e may be manufactured by multi-level binary optics. FIG. 7 is a cross-sectional view illustrating the structure of multilevel binary optics. Multilevel binary optics is an approximation of a shape by multiple planes.

When the shape to be approximated is the sawtooth shape shown by the broken line in FIG. 7, the portion where the height with respect to the surface changes continuously and linearly is approximated to a staircase shape by a plurality of planes. The plurality of planes formed in the multilevel binary optics can be formed by applying a photoresist to the surface of a glass substrate, and repeatedly performing an exposure process, a development process, and an etching process. Therefore, the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 can be manufactured at low cost. Further, since the degree of freedom in designing the width and height of the plane to be formed in the surface direction is high, there is an advantage that various shapes can be approximated.

[Fourth Configuration Example of Reflective Pattern Plate] FIG.
4A is a diagram showing a fourth configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20, FIG. 4A is a front view of a pattern forming surface, and FIG. The DD
FIG. 3C is a cross-sectional view taken along line EE in FIG. The light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 according to the third configuration example shown in FIG.
The anti-reflection regions 44a to 44e having fine irregularities are formed around the reflection regions 40a to 40e. The anti-reflection areas 50a to 50e are provided around the reflection areas 40a to 40e.
Are formed in the same manner as in the third configuration example, but in this configuration example, the anti-reflection regions 50a to 50e are
The difference is that a concave portion is formed around 0e. In this configuration example as well, it is preferable to form a metal film, a dielectric multilayer film, or another high reflection film on the reflection region 43 to increase the reflectance of the reflection regions 40a to 40e with respect to the incident light L1.

The concave portion shields the incident light L1 entering the concave portion from traveling in the direction in which the light regularly reflected by the reflection regions 40a to 40e travels. For this purpose, FIG.
As shown in the figure, the width of the recess in the direction perpendicular to the Y axis and along the surface of the pattern forming surface is w, the height of the recess is h,
Assuming that the incident angle of the incident light L1 with respect to the pattern formation surface is ψ, the height h of the concave portion needs to be set so as to satisfy the following expression (1). h ≧ (w / 2) / tanψ (1) If the above expression (1) is not satisfied, the light regularly reflected on the bottom surface of the concave portion proceeds with the light regularly reflected on the reflection regions 40a to 40e. It progresses in the direction.

As shown in FIG. 8B, when the concave portion is formed so as to satisfy the above expression (1), the incident light L1 incident on the concave portion is blocked, and the reflection regions 40a to 40
e and only the incident light L1 incident on the region 51 other than the antireflection regions 50a to 50e are specularly reflected as reflected light R11 to R13. Further, as shown in FIG. 8C, of the incident light L1 incident on the pattern forming surface, the light incident on the region 51 and the light incident on the reflection regions 40a to 40e are specularly reflected. In the example shown in FIG. 8C, the reflected light R14,
R16 and R18 indicate the reflected light which is incident on the area 51 and is specularly reflected, and the reflected lights R15 and R17 are the reflection areas 40d and 4d.
It shows the reflected light that is incident on 0e and is specularly reflected. As described above, in the present configuration example, by providing the antireflection regions 50a to 50e in which the concave portions are formed around the reflection regions 40a to 40e, the reflected light from the periphery of the reflection regions 40a to 40e is provided as in the third configuration example. Thus, almost no reflected light travels in the direction in which the reflected light regularly reflected by the reflection areas 40a to 40e travels.

Also in the case of this configuration example, the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 according to the present embodiment are connected to the irradiation optical system 10a and the light-receiving optical system 10.
b respectively, as in the third configuration example, not only the light reflected by the reflection regions 40a to 40e but also the region 51
The light reflected by the light source also enters the photoelectric detector 23. The light receiving surface is provided only in the area corresponding to each of the reflection areas 40a to 40e and the area in the vicinity thereof, or the light is reflected by the area 51. What is necessary is just to arrange | position the light-shielding member which blocks the irradiated light on the incident surface of the photoelectric detector 23. FIG. Also in the present configuration example, similarly to the third configuration example, in order to increase the contrast of the images SL1 to SL5 projected on the front surface WS of the wafer W with respect to the periphery, the light transmission side reflection type slit plate 13 is required. What is necessary is just to set suitably according to the contrast which seeks to obtain the width | variety of the antireflection area | region 50a-50e formed around each of the reflection area | regions 40a-40e. The anti-reflection area formed around the reflection areas 40a to 40e of the light-receiving side reflection slit plate 20 has a width in which the image to be re-imaged moves by the vibrating mirror 18, and a surface WS of the wafer W whose optical axis AX What is necessary is just to set according to the range which moves to a direction (surface position detection range). However, it is necessary that the concave portions formed on both the light-transmitting-side reflecting slit plate 13 and the light-receiving-side reflecting slit plate 20 satisfy the relationship of the above expression (1).

[Fifth Configuration Example of Reflective Pattern Plate] FIG. 9
5A is a diagram showing a fifth configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20, and FIG.
(B) is a sectional view taken along line FF in (a), and (c) is a sectional view taken along line GG in (a). 4th mentioned above
In the configuration example, the case where the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern 20 are formed from a glass substrate has been described as an example. Is different. As is well known, by devising the etching on the silicon substrate,
The silicon substrate is anisotropically etched, and (111)
V-grooves composed of crystal planes can be formed. In this configuration example, as shown in FIG. 9A, a V-groove is formed as a concave portion around the reflection region 52 to form the anti-reflection region 53.

As shown in FIGS. 9B and 9C,
Since the (111) crystal planes are formed so as to intersect at an angle of about 55 degrees in the V-groove, the concave portions 50a to 50e having bottom surfaces substantially parallel to the substrate surface are formed as shown in FIG. It is not necessary to satisfy the above equation (1). The reflection area 52 and the anti-reflection area 53 shown in FIG. 9A are formed on the pattern forming surfaces of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 as shown in FIG. It is formed with an array. Further, a metal film, a dielectric multilayer film, and other high-reflection films are formed in the reflection region 52 in the same manner as in the above-described first to fourth configuration examples, and the reflectance of the reflection region 43 with respect to the incident light L1 is formed. Is preferably increased. In this configuration example, the reflective pattern plate is formed of a semiconductor substrate such as a silicon substrate, but the configuration example may be configured of a glass substrate.

[Sixth Configuration Example of Reflective Pattern Plate] FIG. 10
6A and 6B are diagrams showing a sixth configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20, where FIG. 7A is a front view of a pattern forming surface, and FIG. FIG. 6 is a cross-sectional view taken along line HH in FIG.
(C) shows H- in (a) of the light-receiving-side reflective pattern plate 20;
FIG. 3 is a sectional view taken along line H. The pattern forming surfaces of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 according to the sixth configuration example shown in FIG. The prevention area 55 is formed. Reflection areas 54a to 54
e are arranged in a lattice on the pattern formation surface.

As shown in FIG. 10 (b), incident light L2 incident on the pattern forming surface in a substantially perpendicular manner is applied to the reflecting portion regions 54a to 54e of the light-transmitting side reflective pattern plate 13 in the direction normal to the pattern forming surface. A reflection surface is formed as a first reflection portion that reflects obliquely with respect to the light, and a second reflection surface that reflects the incident light L2 substantially in the normal direction of the pattern formation surface is formed in the antireflection area 55.
A reflection surface as a reflection section is formed. FIG. 10 (b)
In, the incident light L2 incident on the reflection area 54d is specularly reflected as reflected light R20, and the incident light L2 incident on the reflection area 54e is specularly reflected as reflected light R21. on the other hand,
The incident light that has entered the anti-reflection area 55 is reflected light R20, R
The light is reflected in a direction different from the traveling direction of 21 (a direction perpendicular to the pattern formation surface). Therefore, it is possible to prevent the light reflected by the anti-reflection area 55 from traveling in the traveling direction of the light reflected by the reflection areas 54a to 54e. Further, as shown in FIG. 10C, the incident light L2 which enters the reflection areas 54a to 54e of the light-receiving side reflection type pattern plate 20 from an oblique direction with respect to the normal to the pattern forming surface.
Is formed as a first reflecting portion that reflects the light substantially perpendicular to the pattern forming surface, and a second reflection that reflects the incident light L2 in an oblique direction with respect to the normal of the pattern forming surface is formed in the anti-reflection area 55. A reflection surface as a part is formed. FIG.
In (c), the incident light L2 incident on the reflection area 54d
Is specularly reflected as reflected light R22, and the incident light L2 incident on the reflection area 54e is specularly reflected as reflected light R23.
On the other hand, the reflected light incident on the anti-reflection area 55 is reflected light R2.
2, R23 is reflected in a direction different from the traveling direction. Therefore, it is possible to prevent the light reflected by the anti-reflection area 55 from traveling in the traveling direction of the light reflected by the reflection areas 54a to 54e.

The light-transmitting-side reflective pattern plate 13 receives the light passing through the condenser lens 12 as incident light L2, which is substantially perpendicular to the pattern forming surface, and reflects light from the reflection areas 54a to 54e.
2 passes through the condenser lens 14, the reflection plate 15, and the objective optical system 16 in FIG.
Are arranged so as to be projected onto the surface WS of the wafer W. In the case of this configuration example, the light source 1
The positions of the condenser lens 1 and the condenser lens 12 may be appropriately changed according to the arrangement of the light-transmitting-side reflective pattern plate 13. The light-receiving-side reflective pattern plate 20 receives the light passing through the condenser lens 19 as an incident light L2 from an oblique direction with respect to the pattern forming surface, and reflects the reflected light regularly reflected by the reflection regions 54a to 54e. It is arranged so as to be guided to the photoelectric conversion element 23 by sequentially passing through the relay lenses 21 and 22 in FIG. The positions of the relay lenses 21 and 22 and the position of the photoelectric conversion element 23 may be appropriately changed according to the arrangement of the light-transmitting-side reflective pattern plate 20. In this configuration example as well, a metal film, a dielectric multilayer film, and other high-reflection films are formed in the reflection regions 54a to 54e to form the reflection region 43 for the incident light L2.
It is preferable that the loss of light amount be prevented as much as possible by increasing the reflectance of the light. Also in this configuration example, the anti-reflection area 55 may be formed only around the reflection areas 54a to 54e.

As described above, the light-transmitting-side reflective pattern plate 13 provided in the irradiation optical system 10a and the light-receiving-side reflective pattern plate 20 provided in the light-receiving optical system 10b of the surface position detecting device according to one embodiment of the present invention. The detailed configuration has been described. In the above description, the case where the configuration of the light-transmitting-side reflective pattern plate 13 and the configuration of the light-receiving-side reflective pattern plate 20 are the same has been described as an example, but different configurations may be used. For example, in the irradiation optical system 10a, the first configuration example as the light transmission side reflection type pattern plate 13 is arranged, and in the light reception optical system 10b, the third configuration example as the light reception side reflection type pattern plate 20 or The fourth configuration example may be provided. The combination of the configuration examples used as the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 is arbitrary.

According to the surface position detecting apparatus according to the embodiment of the present invention described above, the wafer W
Even when the incident angle of the detection light DL applied to the surface WS is set to be large, the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 are used to detect the surface position. A decrease in the amount of light can be prevented, and as a result, the surface position can be detected with high accuracy.

The structure of the surface position detecting device according to the embodiment of the present invention has been described above, and the operation of detecting the position of the surface WS of the wafer W in the optical axis AX direction has been described. The surface position detection apparatus of the present embodiment needs to measure the irradiation position of the detection light DL on the wafer W when performing adjustment at the time of manufacturing the exposure apparatus or performing periodic adjustment. Next, the operation when measuring the irradiation position of the detection light DL will be described. FIG.
FIG. 6 is a top view illustrating a state of detecting an irradiation position of the detection light DL.

In FIG. 11A, reference numeral 5 denotes a reference member 5 provided on the wafer holder 2. The upper surface is set to be substantially the same as the surface WS of the wafer W. As described above, since the reference member 5 is a member that determines the reference position of the wafer stage 3, various patterns are formed on the upper surface thereof as reference patterns.
In the figure, only the first reflection unit 60 and the second reflection unit 62 used for detecting the position of the detection light DL are illustrated, and other patterns are not illustrated. When measuring the irradiation position of the detection light DL, the upper surface of the reference member 5 is used as a test surface.

In FIG. 11A, the detection light DL having an incident angle of 83 degrees or more from the surface position detecting device 10 is shown.
Has been irradiated, and the detection area DA shown in FIG.
3A and 3B show images SL1 to SL5 of a pattern formed on a pattern forming surface of a light-transmitting-side reflective pattern plate 13 irradiated on a surface WS of a wafer W. Note that the first reflecting portion 60 and the second reflecting portion 61 formed on the reference member 5 described above
It is set so that the reflectance difference with respect to the detection light DL or the reflected light is 8% or more, preferably 10% or more. Here, it is assumed that the first reflector 60 has a higher reflectance with respect to the detection light DL than the second reflector 61. This first reflector 6
0 is formed of a metal film or a dielectric multilayer film. For example, to increase the reflectance for the detection light DL,
Gold or aluminum is deposited. When gold is deposited, it is preferable to deposit chromium (Cr) or the like and then deposit gold in order to increase the adhesion to the substrate (reference member 5).

The irradiation position of the detection light DL, that is, the images SL1 to SL
When detecting the irradiation position of L5, first, the main control system 30
XY the wafer stage 3 via the stage drive system 33
The reference member 5 is moved in the plane, and the reference member 5 is arranged near the irradiation position of the detection light DL (for example, the irradiation position of the image SL4). Next, the reference member 5 is moved in the X-axis direction by moving the wafer stage 3 in the X-axis direction (scanning direction SC) at a constant speed.
Is scanned. This operation is performed while changing the position in the Y-axis direction in the detection area DA.
1, scanning is performed in the order of the image SL3, the image SL5, and the image SL2. In this example, the image SL3 is scanned in the −X axis direction. Then, the position of the reference member 5 (the position of the wafer stage 3 in the X-axis direction) and the photoelectric conversion element 23
The relationship with the output signal from is obtained.

Now, a description will be given of a change in the intensity of the signal output from the photoelectric conversion element 23 when the image SL4 is scanned, for example. As shown in FIG. 11B, the image SL4 is the second image.
When the reflection unit 61 is illuminated, the second reflection unit 61 is set to have a low reflectance with respect to the detection light DL, and thus the obtained signal intensity is denoted by a symbol P1 in FIG.
The signal strength at the point marked with is obtained. On the other hand, FIG.
As shown in FIG. 11A, when the image SL4 irradiates the first reflecting unit 60 having a high reflectance with respect to the detection light DL, the obtained signal intensity is denoted by reference symbol P2 in FIG. 11D. The signal strength of the point is obtained. The upper surface of the reference member 5 is set to be substantially the same as the surface of the wafer W, and the position of the wafer stage 3 in the XY plane, and thus the position of the reference member 5, is measured by a laser interferometer (not shown). The irradiation position of the detection light DL can be obtained based on the position on the XY plane of No. 5 and the intensity change of the signal obtained from the photoelectric conversion element 23. When the irradiation position of the detection light DL is measured and the deviation amount of the irradiation position of the detection light DL is obtained, the deviation of the irradiation position is adjusted by finely adjusting the arrangement of the optical members in the irradiation optical system 10a. May be. In addition, a detection error of the surface detection device 10 due to a shift amount of the irradiation position of the detection light DL is obtained and stored as an offset, and this offset is subtracted from a detection result of the surface WS of the wafer W to obtain a correct position. You may do it. In this manner, the fine adjustment of the arrangement of the optical members in the irradiation optical system 10a can be omitted.

As described above, in the present embodiment, the irradiation position of the detection light DL (images SL1 to SL5) is obtained based on the intensity change of the signal obtained from the photoelectric conversion element 23. Therefore, in order to detect the irradiation position of the detection light DL, the signal intensity obtained when the detection light DL irradiates the second reflector 61 and the detection light DL irradiates the first reflector 60. It is necessary to make the difference from the sometimes obtained signal strength a certain value or more. This difference depends on the light receiving characteristics (such as a dynamic range) of the photoelectric conversion element 23. It is considered that the irradiation position of the detection light DL can be measured even if the above difference is small if the photoelectric conversion element 23 having good light receiving characteristics is used, but the photoelectric conversion element 23 having such characteristics is expensive and increases the cost of the apparatus Let it. Thus, even when the generally used photoelectric conversion element 23 is used, the detection light D
In order to detect the irradiation position of L satisfactorily, the first reflection unit 60
The second reflecting section 61 is set so that the difference in reflectance with respect to the detection light DL or reflected light that enters at an incident angle of 83 degrees or more is 8% or more, preferably 10% or more.

The light-transmitting-side reflective pattern plate 1
3 and the light-receiving-side reflective pattern plate 20 in the same manner as the first and third structural examples, the second reflective portion 61 is formed with a fine uneven structure, and the detection light DL incident on the second reflective portion 61 is formed. May be diffracted or scattered to reduce the reflectance with respect to the detection light DL. Further, the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 2
0, as in the fourth configuration example and the fifth configuration example.
1 has a structure in which a concave portion is formed around the first reflecting portion 60,
The reflectance may be reduced by blocking light traveling in the direction of regular reflection with respect to the reference member 5 after entering the concave portion. In this case, when the bottom of the concave portion has a planar shape, it is necessary to set the height of the concave portion so as to satisfy the above-described expression (1). Even when the second reflector 61 is configured as described above, it is preferable to form a metal film or a dielectric multilayer film having a high reflectance with respect to the incident detection light DL on the first reflector 60. .

Further, the first reflecting portion 60 and the second reflecting portion 61 may have the same configuration as the sixth configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20 described above. good. That is, the configuration is such that the detection light DL incident on the first reflection unit 60 is specularly reflected, and the light incident on the second reflection unit 61 is reflected in a direction different from the regular reflection direction of the detection light DL. Even with such a configuration, it is preferable that a metal film or a dielectric multilayer film having a high reflectance with respect to the incident detection light DL be formed on the first reflection unit 60.

In the above description, the case where the reflectance of the first reflector 60 for the detection light DL is higher than the reflectance of the second reflector 61 has been described. The reflectance may be set higher than the reflectance of the one reflecting unit 60. In this case, the light-transmitting-side reflective pattern plate 1 described above is used.
As in the second configuration example of the third and third light-receiving-side reflective pattern plates 20, a configuration in which a fine uneven pattern is formed on the first reflecting portion 60 may be adopted. In addition, a metal film or a dielectric multilayer film having a high reflectance with respect to the incident detection light DL is a second reflection portion 61.
Formed.

In the manufacturing process of the micro device,
First, the reticle R on which the device pattern is formed is placed on a reticle stage (not shown), and the position of the mask M is adjusted. Next, the reference pattern formed on the reference member 5 and the mark for position measurement (not shown) formed on the reticle R are simultaneously observed via the projection optical system PL, and the reticle R
The center (exposure center) of the projected image of the device pattern formed in step (1) is obtained. After the wafer W is placed on the wafer holder 2, the position of the wafer W in the XY plane is measured using an alignment sensor (not shown), and the surface position is periodically adjusted by the method described above. The position of the surface WS of the wafer W is detected using the apparatus 10 (position detection step).

The detection result of the alignment sensor and the detection result of the surface position detecting device 10 are output to the main control system 30.
The main control system 30 moves the wafer W in the XY plane via the stage drive system 33 based on the detection result of the alignment sensor, and performs alignment of the partitioned area (shot area) set on the wafer W, Surface position detecting device 10
Based on the detection result, at least one of the position of the surface WS of the wafer W in the Z-axis direction and the attitude of the wafer W is adjusted (substrate adjustment step). Then, while the illumination light IL is irradiating the reticle R, the main control system 30 synchronously moves the reticle stage and the wafer stage 3 so that the device patterns formed on the reticle R via the projection optical system PL are sequentially changed. The image is transferred to the shot area of the wafer W.

As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment, and can be freely modified within the scope of the present invention. For example, in the above embodiment, the step-and-scan type exposure apparatus has been described as an example, but the present invention is also applicable to a step-and-repeat type exposure apparatus. The light source of the illumination optical system of the exposure apparatus of the present embodiment includes g-line (436 nm), i-line (365 nm), and K
Laser light emitted from an rF excimer laser (248 nm), an ArF excimer laser (193 nm), or an F ₂ laser (157 nm) has been used. it can. For example, when using an electron beam, thermionic emission type lanthanum hexaborite (LaB ₆ ) or tantalum (Ta) can be used as the electron gun.

Further, in the above embodiment, the images SL1 to SL irradiated on the surface WS of the wafer W from the surface position detecting device 10 are used.
Although the longitudinal direction of L5 is set in a direction parallel to the Y axis, the longitudinal direction is substantially 45 degrees with respect to the X axis direction and the Y axis direction.
It is preferable to irradiate an image forming a degree angle. Usually, since the pattern formed on the wafer W is mainly composed of vertical and horizontal straight lines perpendicular to each other, a pattern having a longitudinal direction in the X-axis direction and a pattern having a longitudinal direction in the Y-axis direction are formed on the wafer W. Are formed in large numbers. Here, by irradiating so that the longitudinal direction of the image to be irradiated does not coincide with such a vertical and horizontal linear direction,
Brightness and darkness due to the pattern and non-uniformity of the reflectance can be averaged to improve the detection accuracy of the surface position. Note that X
It is desirable that the angle between the axis and the axis is 45 degrees. However, since it is sufficient that the image of the slit is formed across the vertical and horizontal lines of the pattern, an angle other than 90 degrees, for example, 30 degrees or 60 degrees. There may be.

Next, an embodiment of a method for manufacturing a micro device using an exposure apparatus according to an embodiment of the present invention in a lithography process will be described. FIG. 12 shows a micro device (a semiconductor chip such as an IC or an LSI, a liquid crystal panel,
FIG. 6 is a diagram showing a flowchart of a manufacturing example of a CCD, a thin-film magnetic head, a micromachine, and the like). As shown in FIG. 12, first, in step S10 (design step),
The function / performance design of the micro device (for example, circuit design of a semiconductor device) is performed, and the pattern design for realizing the function is performed. Subsequently, in step S11 (mask manufacturing step), a mask (reticle) on which the designed circuit pattern is formed is manufactured. On the other hand, in step S12 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

Next, in step S13 (wafer processing step), using the mask and the wafer prepared in steps S10 to S12, an actual circuit or the like is formed on the wafer by a lithography technique or the like as described later. . Next, in step S14 (device assembly step), device assembly is performed using the wafer processed in step S13. Step S14 includes, as necessary, steps such as a dicing step, a bonding step, and a packaging step (chip encapsulation).
Finally, in step S15 (inspection step), inspections such as an operation confirmation test and a durability test of the microdevice manufactured in step S14 are performed. After these steps, the microdevice is completed and shipped.

FIG. 13 is a diagram showing an example of a detailed flow of step S13 in FIG. 12 in the case of a semiconductor device. In FIG. 13, in step S21 (oxidation step), the surface of the wafer is oxidized. In step S22 (CVD step), an insulating film is formed on the wafer surface. Step S23 (electrode forming step)
In, electrodes are formed on a wafer by vapor deposition. In step S24 (ion implantation step), ions are implanted into the wafer. Each of the above-described steps S21 to S24 constitutes a pre-processing step in each stage of wafer processing, and is selected and executed according to a necessary process in each stage.

In each stage of the wafer process, when the above-mentioned pre-processing step is completed, the post-processing step is executed as follows. In this post-processing step, first, step S
In 25 (resist forming step), a photosensitive agent is applied to the wafer. Subsequently, in step S26 (exposure step: transfer step), the circuit pattern of the mask is transferred to the wafer by the lithography system (exposure apparatus) and the exposure method described above. Next, step S27
In the (development step: development step), the exposed wafer is developed, and in step S28 (etching step), the exposed members other than the part where the resist remains are removed by etching. And step S
In 29 (resist removing step), unnecessary resist after etching is removed. By repeating these pre-processing and post-processing steps, multiple circuit patterns are formed on the wafer.

If the microdevice manufacturing method of the present embodiment described above is used, the above-described exposure apparatus and the above-described exposure method are used in the exposure step (step S26), and the resolution is improved by the illumination light in the vacuum ultraviolet region. In addition, since the exposure amount can be controlled with high precision, a highly integrated device having a minimum line width of about 0.1 μm can be produced with a high yield.

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

[0083]

As described above, according to the present invention, when the light from the light source is applied to the surface to be inspected as a pattern having a predetermined shape, the light from the light source is reflected by using the reflective pattern plate. Since the light from the light source is transmitted, the loss of the light amount can be suppressed as compared with the related art in which a predetermined pattern is applied to the surface to be inspected. In addition, of the light incident on the reflective pattern plate from the light source, the light reflected on the reflection area is guided to the surface to be inspected, and the light incident on the anti-reflection area is hardly guided on the surface to be inspected. Since the pattern can be irradiated on the surface to be inspected, there is an effect that it is suitable for improving the detection accuracy. Further, in the present invention, when the pattern irradiated on the surface to be inspected is re-imaged on the photoelectric conversion element, the image is re-imaged using the reflective pattern plate, so that light from the surface to be inspected is transmitted. Accordingly, the loss of light amount can be suppressed as compared with the related art in which re-imaging is performed on the photoelectric conversion element. Also, of the light incident on the reflective pattern plate from the test surface, the light reflected on the reflection region is guided to the test surface, and the light incident on the anti-reflection region is hardly guided on the test surface, When detecting the surface position of the surface to be inspected by the principle of the photoelectric microscope, the detection can be performed based on the optical signal having a high signal-to-noise ratio, which is advantageous in improving the detection accuracy. . In the future, in order to improve the detection accuracy of the test surface, it is conceivable to further increase the incident angle of the irradiation light on the test surface. By providing the above-mentioned reflective pattern plate in the optical path from the light source to the test surface and in the optical path from the test surface to the photoelectric conversion element, light emitted from the light source to the test surface and photoelectric conversion from the test surface Since the loss of light quantity for both light reaching the element can be suppressed, the position of the test surface can be detected with high accuracy even if the incident angle of the irradiation light on the test surface is further increased. There is. Further, according to the present invention, since the shape of the reflective pattern plate does not change with time and is constant, the shape accuracy of the pattern irradiated on the surface to be inspected or the shape of the pattern re-imaged on the photoelectric conversion element The accuracy can be improved, and as a result, there is an effect that the detection accuracy of the surface to be inspected can be improved. Further, according to the present invention, the reference member on which the reference pattern including the first reflection portion and the second reflection portion having the reflectance difference of 8% or more is formed is the optical path of the detection light and the reflected light from the test surface. Are arranged in at least one of the optical paths. Therefore, when measuring the irradiation position of the detection light from the change in the amount of reflected light received when scanning the reference member with respect to the detection light irradiated on the test surface with an incident angle of 83 degrees or more,
The reflectance difference between the first reflector and the second reflector is set to 8% or more, and the amount of light obtained when the detection light is applied to the first reflector and the amount of light obtained when the detection light is applied to the second reflector. Since a sufficient difference from the obtained light amount can be obtained, the irradiation position of the detection light can be detected with high accuracy. The angle of incidence of the detection light on the surface to be inspected is expected to increase in the future in order to improve the detection accuracy of the surface position detecting device.
When the detection accuracy of the surface position detecting device is improved, the irradiation position of the detection light on the surface to be detected must be accurately measured. However, if measurement is performed using a reference member on which a conventional reference pattern is formed, a sufficient light amount difference cannot be obtained, and the irradiation position of the detection light cannot be measured with high accuracy. Therefore, if the position detecting device according to the present invention is used, the position detecting device is provided on the reference pattern reference member including the first reflecting portion and the second reflecting portion having a reflectance difference of 8% or more with respect to detection light incident at an incident angle of 83 degrees. Therefore, there is an effect that the detection accuracy of the irradiation position of the detection light can be improved.
Further, according to the present invention, there is provided a surface position detection device capable of detecting the surface position of the substrate with high accuracy, and the surface position of the substrate is accurately determined based on the high-precision surface position detection result of the surface position detection device. Since alignment can be performed, there is an effect that it is extremely suitable for forming a fine pattern on a substrate. According to the present invention, there is provided a surface position detection device capable of detecting the surface position of the substrate with high accuracy,
Since the position of the substrate can be accurately adjusted based on the highly accurate surface position detection result of the surface position detection device and the image of the pattern formed on the mask can be transferred to the substrate with high resolution, a fine There is an effect that it is extremely suitable for forming a pattern.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of an exposure apparatus according to an embodiment of the present invention including a surface position detecting device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which an image of a pattern formed on a light-transmitting-side reflective pattern plate 13 is formed over the entire surface WS of a wafer W.

FIG. 3 is a diagram for explaining the reason why the object-side numerical aperture of the light receiving optical system 10b is designed to be small.

FIG. 4 is a diagram showing a first configuration example of a light-transmitting-side reflective pattern plate 13 and a light-receiving-side reflective pattern plate 20, and FIG.
FIG. 2 is a front view of a pattern forming surface, and FIG. 2B is a cross-sectional view taken along line AA in FIG.

FIGS. 5A and 5B are diagrams showing a second configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20; FIG.
FIG. 2 is a front view of a pattern forming surface, and FIG. 2B is a cross-sectional view taken along line BB in FIG.

FIGS. 6A and 6B are diagrams showing a third configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20, and FIG.
FIG. 2 is a front view of a pattern formation surface, and FIG. 2B is a cross-sectional view taken along line CC in FIG.

FIG. 7 is a cross-sectional view illustrating a structure of multilevel binary optics.

8A and 8B are diagrams illustrating a fourth configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20, and FIG.
5A is a front view of a pattern forming surface, FIG. 5B is a cross-sectional view taken along line DD in FIG. 5A, and FIG. 5C is a cross-sectional view taken along line EE in FIG.

9A and 9B are diagrams showing a fifth configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20, and FIG.
FIG. 3 is a front view showing a configuration example of a reflection area and an anti-reflection area, FIG.
FIG. 3 is a sectional view taken along line GG in FIG.

FIG. 10 is a diagram showing a sixth configuration example of the light-transmitting-side reflective pattern plate 13 and the light-receiving-side reflective pattern plate 20,
(A) is a front view of a pattern forming surface, (b) is a cross-sectional view taken along line HH in (a) of the light-transmitting-side reflective pattern plate 13, and (c) is light-receiving-side reflection. FIG. 3 is a cross-sectional view taken along line HH in FIG.

FIG. 11 is a top view showing a state of detecting an irradiation position of the detection light DL.

FIG. 12 is a flowchart illustrating an example of a micro device manufacturing process.

13 is a diagram showing an example of a detailed flow of step S13 in FIG. 12 in the case of a semiconductor device.

FIG. 14 is a side view showing a main part configuration of a conventional surface position detection device and a main part configuration of an exposure apparatus related to the surface position detection device.

FIG. 15 is an optical path diagram showing that the optical system of the surface position detecting device shown in FIG. 14 is telecentric on both sides.

FIG. 16 is an explanatory diagram of Scheimpflug conditions.

[Explanation of symbols]

3 Wafer Stage (Substrate Stage, Adjustment Device) 4a-4c Support Point (Adjustment Device) 5 Reference Member 11 Light Source 10 Surface Position Detector 10a Irradiation Optical System 10b Light Reception Optical System 13 Transmitting-side Reflective Pattern Plate (Reflective Pattern Plate) 20) light-receiving-side reflective pattern plate (reflective pattern plate) 23 photoelectric conversion element 30 main control system (adjustment device) 33 stage drive system (adjustment device) 40a to 40e reflection area 41 anti-reflection area 44a to 44e anti-reflection area 50a To 50e Anti-reflection area 52 Reflection area 53 Anti-reflection area 54a to 54e Reflection area 55 Anti-reflection area 60 First reflection section 61 Second reflection section DL Detection light IL Illumination light PL Projection optical system R Reticle (mask) W Wafer (substrate) ) WS wafer surface (test surface)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G02B 7/11 MF term (Reference) 2F065 AA37 AA49 BB13 CC20 DD04 DD09 FF01 GG04 HH03 HH12 LL04 LL12 LL59 MM03 PP12 2H051 AA00 AA10 5046 DA05 DA14 DB05

Claims (22)

[Claims] 1. A surface position detecting device for irradiating light from a light source onto a surface to be measured in an oblique direction, guiding light from the surface to be measured to a photoelectric conversion element, and detecting the position of the surface to be measured. A position in the optical path from the light source to the test surface and in at least one of an optical path from the test surface to the photoelectric conversion element, and a position optically conjugate to the test surface or A reflection type pattern plate disposed in the vicinity of the position, wherein the reflection type pattern plate includes a reflection region and an antireflection region formed around the reflection region. . 2. The surface position detecting device according to claim 1, wherein the shape of the reflection area of the reflection type pattern plate is constant. 3. The illuminating optical system according to claim 1, wherein the reflective pattern plate is provided in an irradiating optical system that irradiates light from the light source to the surface to be measured as detection light from an oblique direction. Item 3. A surface position detecting device according to Item 2. 4. The light-receiving optical system according to claim 1, wherein the reflection-type pattern plate is provided in a light-receiving optical system that receives light from the test surface and forms an image on the photoelectric conversion element. The surface position detecting device according to any one of the above. 5. The reflection area of the reflection type pattern plate is positioned so as to regularly reflect incident light from the light source and to guide the incident light to the surface to be inspected, or to directly reflect incident light from the surface to be inspected. The surface position detection device according to any one of claims 1 to 4, wherein the surface position detection device is positioned so as to be reflected and guided to the photoelectric conversion element. 6. The surface position detecting device according to claim 1, wherein the anti-reflection area is formed only around the reflection area. 7. The reflection preventing area has an uneven structure formed on the surface of the reflection type pattern plate, and diffracts or scatters the incident light. The surface position detecting device as described in the above. 8. The surface position detecting device according to claim 7, wherein the uneven shape is formed of multi-level binary optics approximated by a step shape formed by a plurality of planes. 9. The anti-reflection region has a concave portion formed around the reflective region, and the concave portion blocks light traveling in the regular reflection direction after entering the concave portion. The surface position detection device according to claim 5 or 6, wherein 10. The reflection region of the reflection pattern plate includes a first reflection portion, and the antireflection region includes a second reflection portion that reflects incident light in a direction different from that of the first reflection portion. The surface position detecting device according to claim 1, wherein the surface position detecting device is provided. 11. The surface according to claim 1, wherein a reflection film having a high reflectance with respect to the incident light is formed in the reflection area. Position detection device. 12. The surface of the reflection type pattern plate and the surface to be measured are positioned so as to satisfy a Scheimpflug condition with respect to at least one of the irradiation optical system and the light receiving optical system. The surface position detecting device according to claim 1. 13. A surface position detecting device which irradiates a detection light obliquely to a test surface, receives reflected light from the test surface, and detects a position of the test surface. A reference pattern including a first reflecting portion and a second reflecting portion having a reflectance difference of 8% or more with respect to the detection light or the reflected light incident on the surface at an incident angle of 83 degrees or more was formed. A surface position detecting device, comprising: a reference member, wherein the reference member is disposed on at least one of an optical path of the detection light and an optical path of the reflected light. 14. The surface position detecting device according to claim 13, wherein at least one of the first and second reflecting portions is formed of a metal film or a dielectric multilayer film. 15. The apparatus according to claim 15, wherein the second reflecting portion has an uneven structure formed on a surface of the reference member, and reduces a reflectance by diffracting or scattering the incident light. Item 14. A surface position detecting device according to item 13. 16. The second reflecting portion has a concave portion formed around the first reflecting portion, and blocks light traveling in a direction that is regularly reflected with respect to the reference member after being incident on the concave portion. 14. The surface position detecting device according to claim 13, wherein the reflectance is reduced by doing so. 17. The surface position detecting device according to claim 13, wherein the first and second reflecting portions are formed so as to reflect incident light in different directions. 18. The method according to claim 15, wherein a metal film or a dielectric multilayer film having a high reflectance with respect to incident light is formed on the first reflecting portion. A surface position detection device according to claim 1. 19. An exposure apparatus for transferring a pattern formed on a mask onto a substrate, wherein a substrate stage for holding the substrate and a position of a surface of the substrate are detected as positions of the surface to be detected. Item 18. A surface position detection device according to any one of Items 18, and an adjustment device that adjusts at least one of a position and a posture of the substrate on the substrate stage based on a detection result of the surface position detection device. An exposure apparatus comprising: 20. An exposure apparatus for transferring an image of a pattern formed on a mask through a projection optical system to a substrate, comprising: irradiating a detection light from an oblique direction to a surface of the substrate via an irradiation optical system; A surface position detection device that receives light from the surface of the substrate with a light receiving optical system and detects a position of the surface of the substrate; a numerical aperture NA of the projection optical system; and the irradiation optics included in the surface position detection device. An exposure apparatus, wherein an incident angle θ of detection light to a surface of the substrate via a system and a numerical aperture NA1 of the light receiving optical system provided in the surface position detection device satisfy the following conditions. NA ≧ 0.75 θ ≧ 83 degrees NA1 ≦ 0.1 21. The surface position detecting device according to claim 1, wherein the surface position detecting device detects a position of a surface of the substrate as a position of the test surface. The exposure apparatus according to claim 20, wherein: 22. A position detecting step of detecting a position of a substrate using the surface position detecting device provided in the exposure apparatus according to claim 19; and a detection result of the position detecting step. A substrate adjusting step of adjusting at least one of a position and a posture of the substrate, based on the position, a transferring step of irradiating the mask with illumination light and transferring an image of a pattern formed on the mask to the substrate, And a developing step of developing the substrate transferred in the transfer step.