WO2005078778A1 - Lighting optical device, polarization status detector,and exposure system and exposure method - Google Patents

Abstract

A lighting optical device for lighting a surface (M) to be irradiated with a light from a light source (1), wherein a polarization status detecting means (50) for detecting the polarization status of a light flux advancing along a light path between the light source (1) and the surface (M) to be irradiated is provided, and the polarization status detecting means (50) comprises an optical element provided with an optical surface having a pyramid shape or a part-of-pyramid shape, and a light intensity detector for detecting the intensity of light traveling via the optical element.

Description

 Specification

 Illumination optical device, polarization state detector, exposure device, and exposure method

 Technical field

 The present invention relates to an illumination optical device used for an exposure apparatus for manufacturing a micro device such as a semiconductor device, a liquid crystal display device, and a thin film magnetic head in a lithography process, a polarization state detector included in the illumination optical device, The present invention relates to an exposure device provided with an illumination optical device and an exposure method using the illumination optical device.

 Background art

 In a conventional exposure apparatus, a light source having an emitted light beam forms a secondary light source having a large number of light sources on an optical integrator surface. The luminous flux from the secondary light source is restricted via an aperture stop arranged near the rear focal plane of the fly-eye lens as necessary, and then enters the condenser lens.

[0003] The light beam condensed by the condenser lens illuminates the mask on which a predetermined pattern is formed in a superimposed manner. The light transmitted through the mask pattern forms an image on the wafer via the projection optical system. Thus, the mask pattern is projected and exposed (transferred) on the wafer. The pattern formed on the mask is highly integrated, and it is essential to obtain a uniform illuminance distribution on the wafer in order to accurately transfer this fine pattern onto the wafer.

[0004] In addition, when the mask pattern becomes finer and exposure is performed near the resolution limit of the exposure apparatus, light emitted from the aperture stop of the illumination optical system contributes to resolution. Is only the light emitted from the periphery of the aperture stop, and the light emitted from the center of the aperture acts to lower the contrast of the image and has no power. Accordingly, in recent years, by performing annular or multipolar (for example, quadrupole) deformed illumination having a light intensity distribution around the illumination pupil of the illumination optical system, the depth of focus and resolution of the projection optical system are reduced. Attention has been paid to techniques for improving the properties (for example, see JP-A-61-91662 and JP-A-4-101148).

Disclosure of the invention [0005] In the above-described exposure apparatus, when performing annular or multipolar deformed illumination (annular illumination or multipolar illumination) according to the pattern characteristics of the mask, the mask is usually irradiated with light in a non-polarized state. Light up. By optimizing the polarization state of the illuminating light (exposure light) according to the pattern characteristics of the mask, for example, the fineness and directionality of the pattern, the imaging performance of the exposure apparatus can be improved. In particular, for a pattern with a fineness close to the limit resolution of the projection optical system, it is desirable that the illumination light be a light mainly composed of appropriate linearly polarized light according to the directionality of the turn.

 [0006] That is, it is desirable to provide the exposure apparatus with a configuration that can switch the illumination light for illuminating the mask to linearly polarized light or non-polarized light in accordance with the pattern characteristics of the mask. For example, when illuminating a mask having a two-dimensional pattern with a relatively large line width, switching the illumination light to non-polarized light may cause a line width difference between the vertical and horizontal directions. Exposure can be performed at a very high throughput. Further, for example, when illuminating a mask having a pattern with a narrow line width having a predetermined pitch direction, by switching the illumination light to light having linearly polarized light as a main component, the imaging performance of the projection optical system can be improved. (Depth of focus) can be increased.

 When the mask is illuminated with the linearly polarized illumination light while the desired linearly polarized light state is not realized, the imaging performance of a pattern having a predetermined pitch direction and a thin line width is improved. Can not be planned. Therefore, it is necessary to provide a mechanism for detecting and controlling the polarization state of the illumination light in order to realize the optimal illumination conditions according to the pattern characteristics of the mask.

 An object of the present invention is to provide an illumination optical device capable of accurately detecting a polarization state of illumination light such as annular illumination when mounted on an exposure apparatus, and a polarization state detector provided in the illumination optical device. Another object of the present invention is to provide an exposure apparatus having the illumination optical device and an exposure method using the illumination optical device.

The illumination optical device of the present invention is an illumination optical device for illuminating a surface to be illuminated with light of a light source unit, wherein a polarization state of a light beam traveling in an optical path between the light source unit and the surface to be illuminated is changed. A polarization state detection unit for detecting, the polarization state detection unit includes an optical element having an optical surface having a cone shape or a partial shape of a cone, and the optical element. A light intensity detector for detecting the intensity of the reflected light.

 [0010] According to the illumination optical device of the present invention, since the polarization state detecting means includes the optical element having the optical surface having the cone shape or a partial shape of the cone, light is provided around the illumination pupil. When performing deformed illumination such as annular or quadrupole having an intensity distribution, the main component is linearly polarized light whose polarization direction is the direction along the circumference of a circular region centered on the optical axis of the illumination optical device. The polarization state of the light beam can be accurately detected.

 For example, in annular illumination, the annular illumination shape formed at or near the illumination pupil is the shape shown in FIG. 3B, and the annular illumination shape 35 includes a plurality (eight in FIG. 3B) of illumination areas 35a. When the light passing through each of the illumination regions 35a-35h has a main component of linearly polarized light (indicated by a double-headed arrow in FIG. 3B) having a direction of polarization along the outer periphery of the annular illumination shape 35, having 35h. think of. Light passing through each of the illumination areas 35a-35h is incident on the optical surface of an optical element having an optical surface having a cone shape or a partial shape of a cone without changing the polarization state, and the optical surface Thus, since the light is reflected in the same polarization state or transmitted through the optical surface in the same polarization state, the polarization state of light passing through each of the illumination regions 35a to 35h can be accurately detected.

 [0012] In the illumination optical device according to the present invention, the polarization state detecting means may be disposed in the optical path between the light source unit and the illuminated surface, and may transmit a light beam traveling in the optical path to the optical path. An optical path branching member for power branching is provided.

 [0013] According to the illumination optical device of the present invention, since the optical path branching member for branching the light flux between the light source unit and the irradiated surface is also provided, the optical element provided in the polarization state detecting means is provided. And the degree of freedom of arrangement of the light intensity detector can be improved.

 [0014] Further, in the illumination optical device according to the present invention, the polarization state of light passing through the optical surface of the optical element, the polarization state of a light beam that reaches the light intensity detector after passing through the optical element, and the intensity of light may be reduced. It is the same.

According to the illumination optical device of the present invention, the polarization state of the light beam immediately after passing through the optical surface of the optical element and the polarization state of the light beam that reaches the light intensity detector after passing through the optical element are substantially the same. Since they are the same, by detecting the polarization state of the light beam reaching the light intensity detector, it is possible to accurately detect the polarization state of the light beam emitted from the light source unit and illuminating the irradiated surface. it can.

 [0016] In the illumination optical device of the present invention, the polarization state detecting means is disposed in an optical path between the optical surface of the optical element and the light intensity detector, and the optical path branching member includes A film having a function of making the polarization state of the extracted light flux substantially the same as the polarization state of the light flux of the optical path branching member through the optical element is provided. Further, the illumination optical device according to the present invention is characterized in that the film includes a multilayer film.

 [0017] According to the illumination optical device of the present invention, the polarization state of the light beam immediately after passing through the optical surface of the optical element and the polarization state of the light beam that reaches the light intensity detector after passing through the optical element. Since a film or a multilayer film having a function of making the polarization state substantially the same is arranged in the optical path between the optical surface and the light intensity detector, the polarization state of the light flux reaching the light intensity detector is changed. By detecting, it is possible to accurately detect the polarization state of the light beam emitted from the light source unit and illuminating the irradiated surface.

 When a concave mirror is arranged between the optical element and the light intensity detector, the film or the multilayer film is preferably provided on the reflection surface of the concave mirror. When the optical element has a plurality of optical surfaces, it is preferable that the optical element is provided on the optical surface existing between the optical surface closest to the incident side and the light intensity detector. When a light-collecting optical system is interposed between the light-collecting optical system and the detector, it is preferably provided on the optical surface of the light-collecting optical system.

[0019] The illumination optical device of the present invention is characterized in that the polarization state detecting means further includes a concave mirror that collects reflected light passing through the optical element and guides the reflected light to the light intensity detector. . According to the illumination optical device of the present invention, since the polarization state detecting means includes the concave mirror, the light reflected by the optical element can be surely condensed and guided to the light intensity detector.

[0020] The illumination optical device of the present invention is characterized in that the concave mirror is arranged so as to be decentered with respect to the optical axis of the optical element. According to the illumination optical device of the present invention, since the concave mirror can be arranged eccentrically with respect to the optical axis of the optical element, the reflected light reflected by the optical element is condensed at a desired position and is condensed. Can lead to an intensity detector, The degree of freedom in the arrangement of the optical element and the light intensity detector included in the polarization state detecting means can be improved.

 Further, in the illumination optical device according to the present invention, the optical element and the light intensity detector are respectively arranged opposite to each other at a position sandwiching the optical path between the light source unit and the irradiated surface. It is characterized by that.

 According to the illumination optical device of the present invention, since the optical element and the light intensity detector are arranged opposite to each other at a position sandwiching the optical path between the light source unit and the surface to be irradiated, a simple configuration is provided. Thereby, the polarization state of the light beam required to illuminate the irradiated surface can be detected.

 [0023] The illumination optical device of the present invention may further include a light-collecting optical system in which the polarization state detecting means condenses the light transmitted through the optical element and guides the light to the light intensity detector. Features. Further, the illumination optical device of the present invention is characterized in that the condensing optical system includes a lens.

 According to the illumination optical device of the present invention, since the polarization state detecting means is provided with the condensing optical system composed of a lens or the like, the transmitted light transmitted through the optical element can be surely condensed. It can be led to a light intensity detector.

 [0025] The illumination optical device of the present invention is characterized in that it has another optical surface having a cone shape or a partial shape of a cone. ADVANTAGE OF THE INVENTION According to the illumination optical device of this invention, a light beam can be effectively guided to a condensing optical system using two optical surfaces having a cone shape or a partial shape of a cone.

 [0026] Further, the illumination optical device of the present invention is characterized in that the optical surface of the optical element is convex, and the another optical surface is concave. According to the illumination optical device of the present invention, the optical element has an optical surface having a convex cone shape or a partial shape of a cone, and another optical surface having a concave cone shape or a partial shape of a cone. , The burden on the condensing optical system can be reduced.

 [0027] Further, in the illumination optical device of the present invention, the optical elements are arranged such that the optical surface having the convex surface and the another optical surface having the concave surface are located in order from the light incident side. It is characterized by being placed.

[0028] According to the illumination optical device of the present invention, light having a convex cone shape or a partial cone shape is provided. Since the optical surface is located on the light incident side, setting of the Brewster angle on this convex optical surface can be easily realized. Further, since the divergent Z-converged state of the light beam can be made closer to the state at the time of incidence by the concave optical surface, the burden on the light-collecting optical system can be reduced.

 [0029] The illumination optical device of the present invention further includes an S-polarized light generator arranged in an optical path between the light source unit and the surface to be illuminated, and the S-polarized light generator includes an S-polarized light generator. Based on the luminous flux, of the illumination light illuminated on the surface to be illuminated, a light beam illuminated on the surface to be illuminated in a specific incident angle range with respect to the surface to be illuminated is in a polarization state mainly composed of S-polarized light It is characterized by being generated as light.

 According to the illumination optical device of the present invention, of the illumination light applied to the surface to be illuminated, the light beam illuminated to the surface to be illuminated in a specific incident angle range is mainly S-polarized with respect to the surface to be illuminated. S-polarized light generation means that generates light in the polarization state as a component, so that the surface to be irradiated is illuminated with illumination light that has a higher contrast compared to light in the polarization state containing P-polarized light as the main component. The surface can be illuminated. Therefore, when the illumination optical device is mounted on the exposure apparatus, the mask can be illuminated with optimal illumination light according to the pattern characteristics of the mask to be irradiated.

 [0031] The illumination optical device of the present invention further includes a circumferentially polarized light generating unit disposed in an optical path between the light source unit and the irradiated surface, and the circumferentially polarized light generating unit includes: Based on the light flux from the light source unit, a specific annular zone, which is a predetermined annular zone centered on the optical axis of the illumination optical device, in a pupil plane of the illumination optical device or in a plane near the pupil plane. The illumination light passing through at least a part of the specific annular zone is generated as light in a polarization state mainly composed of linearly polarized light having a polarization direction in a circumferential direction of the specific annular zone.

[0032] According to the illumination optical device of the present invention, the illumination light passing through at least a part of the specific orbicular zone, which is the predetermined orbicular zone around the optical axis, is transmitted to the circumference of the specific orbicular zone. Since the device includes a circumferentially polarized light generation unit that generates linearly polarized light whose main direction is a polarization direction and generates the polarized light, the illuminated surface can be illuminated with illumination light having high contrast. . Therefore, when the illumination optical device is mounted on the exposure apparatus, the mask can be illuminated with the optimal illumination light according to the pattern characteristics of the mask to be irradiated. [0033] Further, in the illumination optical device of the present invention, the optical element is arranged in an optical path between the S-polarized light generating means or the circumferentially polarized light generating means and the light intensity detector. Features.

 According to the illumination optical device of the present invention, since the optical element is disposed in the optical path between the S-polarized light generation means or the circumferential direction polarization generation means and the light intensity detector, the S-polarized light generation means or the circumferential direction The light beam having the polarization state generated by the polarization generation means is reliably guided to the light intensity detector via the optical element, and the polarization state of the light beam can be accurately detected.

 [0035] Further, the illumination optical device of the present invention is characterized in that the cone or a part of the cone has a conical shape or a partial shape of a cone.

 [0036] Further, the illumination optical device of the present invention is characterized in that the cone shape or a partial shape of the cone has a pyramidal shape or a partial shape of a pyramid.

 An exposure apparatus of the present invention is an exposure apparatus for transferring a pattern of a mask onto a photosensitive substrate, wherein the illumination optical device of the present invention for illuminating the mask and an image of the pattern of the mask A projection optical system for forming on a photosensitive substrate.

 [0038] According to the exposure apparatus of the present invention, since the illumination optical device according to any one of the present invention is provided, it is possible to perform illumination with light having an optimum polarization state corresponding to the characteristics of the pattern of the mask. And good exposure can be performed.

 [0039] Further, according to the exposure method of the present invention, in the exposure method of transferring a predetermined pattern onto a photosensitive substrate, the predetermined pattern can be obtained by using the illumination optical device according to any one of the present invention. The method includes an illuminating step of illuminating the formed mask, and a transferring step of transferring the predetermined pattern onto the photosensitive substrate.

According to the exposure method of the present invention, since the mask is illuminated using the illumination optical device of the present invention, it is possible to illuminate with light having an optimal polarization state corresponding to the characteristics of the pattern of the mask. Good exposure can be performed.

[0041] Further, the polarization state detector of the present invention is applied to an illumination optical device that illuminates an irradiated surface with light from a light source unit, and travels along an optical path between the light source unit and the irradiated surface. Luminous flux A polarization state detector for detecting the polarization state of the light, wherein the polarization selection means for selecting the light of the circumferential polarization component or the light of the radial polarization component from the light flux; A light intensity detector for detecting the light of the circumferential polarization component or the light of the radial polarization component.

 [0042] According to the polarization state detector of the present invention, in the predetermined cross section of the light beam from the light source unit, the circumferentially polarized light having the polarization direction in the circumferential direction around the predetermined point or the radius around the predetermined point. Since the radially polarized light having the polarization direction in the direction is selectively extracted and the light intensity of the extracted circumferentially polarized light or radially polarized light is detected, it is necessary to accurately detect the degree of the circumferentially polarized light of the light beam. Can be. Here, the circumferential polarization corresponds to the polarization that becomes S-polarized with respect to the irradiated surface, and the radial polarization corresponds to the polarization that becomes P-polarized with respect to the irradiated surface.

 Further, the polarization state detector of the present invention is characterized in that the polarization selecting means has an optical element provided with an optical surface having a cone shape or a partial shape of a cone shape. ADVANTAGE OF THE INVENTION According to the polarization state detector of this invention, a circumferentially polarized light or a radially polarized light can be selectively and simply transmitted efficiently using an optical surface having a cone shape or a partial shape of a cone shape. be able to. As a configuration for selectively transmitting the circumferentially polarized light or the radially polarized light, a configuration in which a groove or the like is provided in the circumferential direction or the radial direction on the light-transmitting substrate may be considered. It is more advantageous to use an optical surface having a partial shape of the shape or the shape of a cone in terms of ease of manufacture and accuracy.

 [0044] Further, the polarization state detector of the present invention is further characterized by further comprising a concave mirror that condenses the reflected light via the optical element and guides the reflected light to the light intensity detector. ADVANTAGE OF THE INVENTION According to the polarization state detector of this invention, the reflected light which is reflected by the optical surface of an optical element and has a circumferentially polarized light as a main component can be condensed reliably, and can be guide | induced to a light intensity detector.

 [0045] Further, the polarization state detector of the present invention is further characterized by further comprising a condensing optical system that condenses the light transmitted through the optical element and guides the light to the light intensity detector. ADVANTAGE OF THE INVENTION According to the polarization state detector of this invention, the transmitted light which permeate | transmits by the optical surface of an optical element and which makes a radial direction polarized light a main component can be condensed reliably, and can be guide | induced to a light intensity detector.

Further, the polarization state detector according to the present invention may be configured such that the cone shape or a part of the cone shape is It is characterized in that the shape has a conical shape or a partial shape of a cone.

 [0047] Further, the polarization state detector of the present invention is characterized in that the pyramidal shape or a part of the pyramid shape has a pyramidal shape or a partial pyramid shape.

 [0048] Further, in the polarization state detector according to the present invention, the polarization selecting means includes a phase shifter and a polarizer, and at least one of the phase shifter and the polarizer is rotatable about an optical axis. It is characterized by comprising. ADVANTAGE OF THE INVENTION According to the polarization state detector of this invention, a polarization state can be measured using a rotational retarder method, and the force of the measurement result can also calculate the degree of circumferential polarization or the degree of radial polarization.

 [0049] The polarization state detector of the present invention is further characterized by further comprising setting means for setting at least four states in which the relative rotation angles of the phase shifter and the polarizer are different. And According to the polarization state detector of the present invention, it is possible to measure four status parameters.

 [0050] Further, in the polarization state detector according to the present invention, the light intensity detector is disposed on a plane optically substantially conjugate with an illumination pupil plane of the illumination optical device, and is optically substantially aligned with the illumination pupil plane. It is characterized by detecting the light intensity distribution on the shared surface. According to the polarization state detector of the present invention, the polarization state on the illumination pupil plane can be measured.

 [0051] Further, the polarization state detector of the present invention further includes processing means for processing an output from the light intensity detector, wherein the processing means performs a relative operation between the phase shifter and the polarizer. A state of the light of the circumferentially polarized light component or the light of the radially polarized light component is output based on information on a rotation angle and information on the light intensity distribution by the light intensity detector.

 [0052] Further, the polarization state detector according to the present invention includes an optical path branching member that is disposed in the illumination optical device and that branches a light flux that travels along the optical path of the irradiated surface from the light source unit from the optical path. It is characterized in that it is arranged in the optical path of the split light beam.

 According to the polarization state detector of the present invention, since the light path branching member for branching the light beam from the illumination light path is provided, the arrangement of the polarization selection means and the light intensity detector in the polarization state detector is provided. Degree of freedom can be improved.

Further, the illumination optical device of the present invention provides illumination light for illuminating an irradiated surface with light having a light source unit. A polarization state detector according to the present invention, and an optical path branching member for branching a light beam traveling in an optical path between the light source unit and the irradiated surface from the optical path. It is characterized by the following.

 According to the illumination optical device of the present invention, the surface to be illuminated can be illuminated by the polarization state detector of the present invention in a state where the polarization state of the illumination light to the surface to be illuminated is accurately grasped.

 Further, the exposure apparatus of the present invention is an exposure apparatus for transferring a pattern of a mask onto a photosensitive substrate, the illumination optical apparatus of the present invention for illuminating the mask, and an image of the pattern of the mask. And a projection optical system for forming on the photosensitive substrate.

 According to the exposure apparatus of the present invention, since the illumination optical apparatus of the present invention is provided, it is possible to perform illumination with light having an optimal polarization state corresponding to the characteristics of the pattern of the mask, and to perform favorable exposure. It can be carried out.

 [0058] The exposure method of the present invention is an exposure method for transferring a mask pattern onto a photosensitive substrate, and illuminates the mask on which the predetermined pattern is formed using the illumination optical device of the present invention. An illumination step and a transfer step of transferring the predetermined pattern onto the photosensitive substrate are included.

 [0059] The exposure method of the present invention is an exposure method for transferring a pattern of a mask onto a photosensitive substrate, the method comprising: illuminating a mask on which the predetermined pattern is formed; And a polarization state detection step of detecting the polarization state of a light beam directed to the mask or the photosensitive substrate using the polarization state detector of the present invention. Features.

 According to the exposure method of the present invention, illumination can be performed with light having an optimal polarization state corresponding to the characteristics of the pattern of the mask, and favorable exposure can be performed.

 Brief Description of Drawings

FIG. 1 is a view showing a schematic configuration of an exposure apparatus working in a first embodiment.

 FIG. 2 is a diagram illustrating a schematic configuration of a 1Z2 wavelength plate and a deborizer included in an illumination optical device according to a first embodiment.

FIG. 3A is a diagram showing a schematic configuration of a phase member assembly according to the first embodiment. [3B] FIG. 3B is a diagram showing an annular illumination shape formed at or near the illumination pupil of the illumination optical device according to the first embodiment.

[4] FIG. 4 is a diagram illustrating a schematic configuration of a conical axicon system included in the illumination optical device according to the first embodiment.

[5] FIG. 5 is a diagram for explaining the action of the conical axicon system on the secondary light source formed in the annular illumination according to the first embodiment.

[6] FIG. 6 is a diagram illustrating a schematic configuration of a first cylindrical lens pair and a second cylindrical lens pair provided in the illumination optical device according to the first embodiment.

[7] FIG. 7 is a diagram for explaining the effect of the zoom lens on a secondary light source formed in annular illumination that is powerful according to the first embodiment.

[8] FIG. 8 is a diagram illustrating a schematic configuration of a polarization monitor provided in the illumination optical device according to the first embodiment.

[9] FIG. 9 is a diagram illustrating a schematic configuration of a polarization monitor provided in an illumination optical device according to a second embodiment.

[10] FIG. 10 is a diagram illustrating a schematic configuration of a polarization monitor provided in an illumination optical device according to a third embodiment.

{11} A diagram showing a schematic configuration of a polarization monitor provided in an illumination optical device according to a fourth embodiment.

[12] FIG. 12 is a diagram illustrating a schematic configuration of a wafer surface polarization monitor provided in an exposure apparatus according to an embodiment of the present invention.

[13] FIG. 13 is a diagram showing a schematic configuration of another modification of the wafer polarization monitor provided in the exposure apparatus according to the embodiment of the present invention.

 FIG. 14 is a view for explaining detection means of the wafer surface polarization monitor of FIG. 13.

 FIG. 15 is a flowchart showing a method for manufacturing a semiconductor device as a micro device according to an embodiment of the present invention.

 FIG. 16 is a flowchart showing a method of manufacturing a liquid crystal display element as a micro device according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION With reference to the drawings, a description will be given of an exposure apparatus according to the first embodiment of the present invention. FIG. 1 is a diagram showing a schematic configuration of an exposure apparatus according to this embodiment. In the following description, the XYZ orthogonal coordinate system shown in FIG. 1 is set, and the positional relationship of each member will be described with reference to the XYZ orthogonal coordinate system. The XYZ orthogonal coordinate system is set so that the X axis and the Y axis are parallel to the wafer W, and the Z axis is set in a direction orthogonal to the wafer W. The illumination optical device according to this embodiment is configured to perform annular illumination.

 As shown in FIG. 1, an exposure apparatus that works in this embodiment supplies, for example, light having a wavelength of about 193 nm as a laser light source (light source unit) 1 for supplying exposure light (illumination light). An ArF excimer laser light source or a KrF excimer laser light source that supplies light with a wavelength of about 248 nm is provided. A substantially parallel light flux emitted from the laser light source 1 along the Z direction enters a beam expander 2 having a rectangular cross section elongated in the X direction and having a pair of lenses 2a and 2b. Each of the lenses 2a and 2b has a negative refractive power and a positive refractive power in the YZ plane of FIG. 1, respectively. Therefore, the light beam incident on the beam expander 2 is enlarged in the YZ plane of FIG. 1 and shaped into a light beam having a predetermined rectangular cross section.

 [0064] The parallel light beam passing through the beam expander 2 as a shaping optical system is reflected by the bending mirror 3 and deflected in the Y direction. Then, the crystal optical axis rotates around the optical axis AX, and The light enters the quarter-wave plate 11 that is configured to be insertable and removable from the axis AX. Here, when elliptically polarized light is incident, the 1Z4 wavelength plate 11 sets the crystal optical axis of the 1Z4 wavelength plate 11 according to the characteristics of the incident elliptically polarized light, thereby converting the elliptically polarized light into a linear beam. It has the function of converting to polarized light.

 That is, when a KrF excimer laser light source or an ArF excimer laser light source is used as the laser light source 1, the laser light source 1 emits substantially linearly polarized light, for example, linearly polarized light having a degree of polarization of 95% or more.

Here, the degree of polarization V is represented by the following equation (a). In equation (a), SO is the total intensity, S1 is the horizontal linear polarization intensity minus the vertical linear polarization intensity, S2 is the 45-degree linear polarization intensity minus 135-degree linear polarization intensity, and S3 is the clockwise circular polarization intensity Negative left-handed circularly polarized light Intensity is indicated respectively. Here, SO-S3 is called a status parameter. V = (Sl ² + S2 ² + S3 ² ) ^1/2 / S0 (a)

 Usually, in the optical path between the laser light source 1 and the 1Z4 wavelength plate 11, a plurality of right-angle prisms (not shown) as rear-surface reflecting mirrors are arranged. Generally, when the linearly polarized light that enters the right-angle prism as the back reflector does not match the P-polarized light or the S-polarized light with respect to the incident surface of the right-angle prism, the linearly polarized light becomes elliptically polarized due to total reflection by the right-angle prism. Change. Therefore, for example, even when the incident light changes from a linear polarization force to an elliptical polarization through a right-angle prism, the crystal optic axis of the 1Z4 wavelength plate 11 is changed according to the characteristics of the elliptically polarized light incident on the 1Z4 wavelength plate 11. By setting, the incident light can be changed from elliptically polarized light to linearly polarized light.

 The light beam that has passed through the 1Z4 wavelength plate 11 passes through the 1Z2 wavelength plate 10 and the deborizer (non-polarizing element) 20. FIG. 2 is a diagram showing a schematic configuration of the 1Z2 wavelength plate 10 and the deborrizer 20. As shown in FIG. 2, the 1Z2 wavelength plate 10 is configured such that the crystal optical axis is rotatable about the optical axis AX. Further, the deborizer 20 includes a wedge-shaped quartz prism 20a and a wedge-shaped quartz prism 20b having a shape complementary to the quartz prism 20a. The quartz prism 20a and the quartz prism 20b are configured as an integral prism assembly so that they can be inserted into and removed from the illumination optical path.

 When the crystal optic axis of the 1Z2 wavelength plate 10 is set to make an angle of 0 ° or 90 ° with respect to the plane of polarization of the linearly polarized light incident thereon, the linearly polarized light incident on the 1Z2 wavelength plate 10 Pass through without change in the polarization plane. When the crystal optic axis of the 1Z2 wave plate 10 is set to form an angle of 45 degrees with respect to the plane of polarization of the linearly polarized light that enters, the light of the linearly polarized light that enters the 1Z2 wave plate 10 has a plane of polarization. It is converted to linearly polarized light that has changed by 90 degrees. Furthermore, if the crystal optic axis of the quartz prism 20a is set to make an angle of 45 degrees with respect to the plane of polarization of the linearly polarized light that enters, the linearly polarized light that enters the quartz prism 20a will be in an unpolarized state. Converted to light (unpolarized).

[0069] In this embodiment, the configuration is such that, when the debolizer 20 is positioned in the illumination optical path, the crystal optic axis of the quartz prism 20a forms an angle of 45 degrees with respect to the plane of polarization of the linearly polarized light that enters. Have been. By the way, the crystal optic axis of the quartz prism 20a is incident When the angle is set to 0 degree or 90 degrees with respect to the polarization plane of the linearly polarized light, the linearly polarized light that has entered the quartz prism 20a passes through without change in the polarization plane. When the crystal optic axis of the 1Z2 wave plate 10 is set to make an angle of 22.5 degrees with respect to the plane of polarization of the linearly polarized light that enters, the linearly polarized light that enters the 1Z2 wave plate 10 is polarized. The light is converted into unpolarized light that includes a linearly polarized light component that passes through the plane without change and a linearly polarized light component whose polarization plane has changed by 90 degrees.

 In the present embodiment, as described above, linearly polarized light enters the 1Z2 wavelength plate 10. When the devolarizer 20 is positioned in the illumination optical path, if the crystal optic axis of the 1Z2 wave plate 10 is set to make an angle of 0 or 90 degrees with respect to the plane of polarization of the linearly polarized light, the 1Z2 wave plate 10 The linearly polarized light that has entered the prism passes through the quartz prism 20a without changing the plane of polarization. Since the crystal optic axis of the quartz prism 20a is set at an angle of 45 degrees with respect to the plane of polarization of the linearly polarized light that enters, the linearly polarized light that has entered the quartz prism 20a is unpolarized light. Is converted to

 On the other hand, if the crystal optic axis of the 1Z2 wavelength plate 10 is set to form an angle of 45 ° with respect to the plane of polarization of the linearly polarized light incident thereon, the light of the linearly polarized light incident on the 1Z2 wavelength plate 10 has a polarization plane of The light becomes linearly polarized light changed by 90 degrees and enters the quartz prism 20a. Since the crystal optic axis of the quartz prism 20a is set at an angle of 45 degrees with respect to the plane of polarization of the linearly polarized light that enters, the linearly polarized light that has entered the quartz prism 20a is unpolarized light. Is converted to The light depolarized through the quartz prism 20a passes through a quartz prism 20b as a compensator for compensating the traveling direction of the light.

 [0072] On the other hand, when the debolizer 20 is retracted from the illumination optical path, the crystal optic axis of the 1Z2 wavelength plate 10 is set to make an angle of 0 or 90 degrees with respect to the plane of polarization of the linearly polarized light to be incident. Then, the linearly polarized light that has entered the 1Z2 wavelength plate 10 passes without changing the polarization plane. On the other hand, if the crystal optic axis of the 1Z2 wave plate 10 is set to make an angle of 45 degrees with respect to the plane of polarization of the linearly polarized light that enters, the light of the linearly polarized light that enters the 1Z2 wave plate 10 has a polarization plane of 90 degrees. Only the changed linearly polarized light.

As described above, in this embodiment, the light can be converted into non-polarized light by inserting and positioning the debolalizator 20 in the illumination light path. Also Deborizer (1) By retracting 20 from the illumination optical path and setting the crystal optic axis of the 1Z2 wave plate 10 at an angle of 0 or 90 degrees to the plane of polarization of the linearly polarized light to be incident, the linear polarization state The light travels without change. Furthermore, the polarization plane was changed by 90 degrees by setting the depolarizer 20 to retract the illumination optical path force and setting the crystal optic axis of the 1Z2 wave plate 10 at 45 degrees with respect to the plane of polarization of the linearly polarized light to be incident. It can be converted to linearly polarized light.

[0074] The light beam that has passed through the devolarizer 20 enters the diffractive optical element 4a. Generally, a diffractive optical element (DOE) is formed by forming a step having a pitch of about the wavelength of exposure light (illumination light) on a glass substrate, and has an action of diffracting an incident beam to a desired angle. Specifically, the diffractive optical element 4a has a function of forming an annular light intensity distribution in the far field (or Fraunhofer diffraction region) when a parallel light beam having a rectangular cross section enters. Therefore, the light beam having passed through the diffractive optical element 4a forms an orbicular light intensity distribution at the pupil position of the afocal lens 85 described later, that is, a light beam having an orbicular cross section. The diffractive optical element 4a is configured to be retractable from the illumination optical path.

 The light beam that has passed through the diffractive optical element 4a enters an afocal lens (relay optical system) 85. The afocal lens 85 is set such that the front focal position and the position of the diffractive optical element 4a almost coincide with each other, and the rear focal position almost coincides with the position of a predetermined surface 86 indicated by a broken line in the figure. It is a focal system (a non-focus optical system). Therefore, the substantially parallel light beam incident on the diffractive optical element 4a forms a ring-shaped light intensity distribution on the pupil plane of the afocal lens 85, and then emerges from the afocal lens 85 as a substantially parallel light beam. .

Note that in the optical path between the front lens group 85a and the rear lens group 85b of the afocal lens 85, the pupil or its vicinity is provided with a phase member assembly (S-polarized light generating means and circular Circular polarization generating means) 16, a conical axicon system 87, a first pair of cylindrical lenses 88, and a second pair of cylindrical lenses 89 are arranged. The luminous flux that has been converted into linearly polarized light or non-polarized light through the 1Z2 wave plate 10 and the deborrizer 20 passes through the front lens group 85a of the afocal lens 85, and is transmitted to the phase member assembly 16. Incident. FIG. 3A is a diagram showing a schematic configuration of the phase member assembly 16. The phase member assembly 16 is made up of FIG. 3A, as shown in FIG. 3A, and the eight alignment members 16a, 16b, 16c, 16d, 16e, 16f, 16g, 16h. It is provided so that it can be inserted and removed from the optical path. Each of the phase members 16a to 16h generates linearly polarized light based on the light beam incident on each of the phase members 16a to 16h, and changes the polarization direction of the linearly polarized light as necessary.

 Specifically, when linearly polarized light having a horizontal polarization direction in the drawing enters the phase member assembly 16, the phase members 16 a and 16 e have an angle of 0 ° with respect to the horizontal direction in the drawing. It is composed of a 1Z2 wave plate that has a crystal optic axis in the direction that it forms. Further, the phase members 16c and 16g are each formed of a 1Z2 wave plate having a crystal optical axis in a direction forming an angle of 45 degrees with the horizontal direction in the figure. Further, the phase members 16b and 16f are each constituted by a 1Z2 wavelength plate having a crystal optical axis in a direction making an angle of 22.5 degrees counterclockwise with respect to the horizontal direction in the drawing. Further, the phase members 16d and 16h are each formed of a 1Z2 wave plate having a crystal optical axis in a direction forming an angle of 22.5 degrees clockwise with respect to the horizontal direction in the figure.

Here, for example, in circular illumination or annular illumination, the polarized light (radially polarized light) whose vibration direction is the radial direction (radial direction) of the illumination area with respect to the traveling direction of the illumination light (exposure light). P-polarized light for wafer _W (mask M). Also, for example, in circular illumination or annular illumination, the polarized light (circumferential polarized light) whose oscillation direction is the circumferential direction of the illumination area with respect to the traveling direction of the illumination light (exposure light) is applied to the wafer W (mask M). ) And S-polarized light. The phase member assembly 3D 16 transmits the light beam irradiated on the wafer W within a specific incident angle range to the wafer W in the illumination light irradiated on the wafer W based on the light beam incident on the phase member 3 & 3D 16. On the other hand, it is generated as light in a polarization state mainly composed of S-polarized light. Further, based on the light beam incident on the phase member assembly 16, the phase member assembly 16 is located at a predetermined position centered on the optical axis of the illumination optical device in the illumination pupil plane of the illumination optical device or in a plane in the vicinity thereof. The illumination light that passes through at least a part of the specific annular zone, which is the annular zone, is generated as light in a polarization state mainly composed of linearly polarized light whose polarization direction is the circumferential direction of the specific annular zone. .

[0080] Therefore, by passing through the phase member ^ & solid 16 as shown in Fig. 3B, the annular illumination shape (specific annular zone area) 35 is formed in the illumination pupil plane of the illumination optical device or in the vicinity thereof. Formed It is. As shown in FIG. 3B, a plurality (eight in FIG. 3B) of areas 35a, 35b, 35c, 35d, 35e, 35f, 35g, along the circumference of a circle centered on the optical axis AX of the illumination optical device. 35h, and the areas 35a to 35h correspond to the phase members 16a to 16h, respectively. As the illuminating light passes through each of the phase members 16a-16h, the polarization state of the light beam passing through each of the regions 35a-35h changes in the direction along the outer periphery of the annular illumination shape 35 in the polarization direction (indicated by a double-headed arrow in the figure). The wafer W becomes the S-polarized state.

 Accordingly, it is possible to change the light irradiated on the mask M (wafer W) into a polarization state mainly composed of S-polarized light with respect to the mask M (wafer W). By retracting the phase member assembly 16 from the optical path of the illumination optical device, when the illumination light is in a non-polarized state, the non-polarized state of the illumination light can be irradiated onto the mask M. Further, when the optical system (illumination optical system or projection optical system) on the wafer W side with respect to the phase member assembly 16 has polarization aberration (retardation), the polarization direction is caused by the polarization aberration. May change. In this case, the state of changing the polarization direction by the phase member assembly 16 may be set in consideration of the influence of the polarization aberration of these optical systems. In addition, when a reflection member is disposed in the optical system on the wafer W side of the phase member assembly 16, the reflected light may have a phase difference for each polarization direction in the reflection member. Also in this case, the state in which the polarization direction is changed by the phase member assembly 16 may be set in consideration of the phase difference of the light beam caused by the polarization characteristics of the reflection surface.

 The luminous flux of the mask M (wafer W) set to a polarization state mainly composed of S-polarized light through the phase member assembly 16 enters the conical axicon system 87. FIG. 4 is a diagram showing a schematic configuration of the conical axicon system 87. The conical axicon system 87 includes, in order from the light source side, a first prism member 87a having a flat surface facing the light source side and a concave conical refraction surface facing the mask side, and a flat surface facing the mask M side and facing the light source side. And a second prism member 87b having a convex conical refracting surface.

[0083] The concave conical refracting surface of the first prism member 87a and the convex conical bending surface of the second prism member 87b are formed complementarily so as to be able to abut each other. Further, at least one of the first prism member 87a and the second prism member 87b is configured to be movable along the optical axis AX, and the concave conical refraction surface of the first prism member 87a and the second prism member 87b The distance from the convex conical refracting surface is variable.

 Here, in a state where the concave conical refraction surface of the first prism member 87a and the convex conical refraction surface of the second prism member 87b are in contact with each other, the conical axicon system 87 is And has no effect on the formed annular secondary light source. However, when the concave conical refracting surface of the first prism member 87a and the convex conical refracting surface of the second prism member 87b are separated from each other, the conical axicon system 87 functions as a so-called beam expander. Accordingly, the angle of the light beam incident on the predetermined surface 86 indicated by the broken line in FIG. 1 changes with the change of the interval of the conical axicon system 87.

 FIG. 5 is a diagram for explaining the operation of the conical axicon system 87 with respect to a secondary light source formed in annular illumination. The smallest ring-shaped secondary light source formed when the interval between the conical axicons 87 is 0 and the focal length of the zoom lens 90 described later is set to the minimum value (hereinafter referred to as “standard state”). 130a is the outer diameter and inner diameter of the conical axicon system 87 that are not changed by expanding the interval of the conical axicon 87 from 0 to a predetermined value (the difference between the outer diameter and the inner diameter 1Z2: indicated by the arrow in the figure). Changes to the expanded annular light source 130b. That is, by the action of the conical axicon system 87, both the annular zone ratio (inner diameter Z outer diameter) and the size (outer diameter) change without changing the width of the annular secondary light source.

 FIG. 6 shows a schematic configuration of the first cylindrical lens pair 88 and the second cylindrical lens pair 89 arranged in the optical path between the front lens group 85a and the rear lens group 85b of the afocal lens 85. FIG. As shown in FIG. 6, the first pair of cylindrical lenses 88 are arranged in order from the light source side, for example, like the first cylindrical negative lens 88a having a negative refractive power in the YZ plane and having no refractive power in the XY plane. The first cylindrical positive lens 88b has a positive refractive power in the YZ plane and has no refractive power in the XY plane. On the other hand, the second cylindrical lens pair 89 includes, in order from the light source side, for example, a second cylindrical negative lens 89a having a negative refractive power in the XY plane and having no refractive power in the YZ plane, and the same in the XY plane. A second cylindrical positive lens 89b having a positive refractive power and having no refractive power in the YZ plane.

[0087] The first cylindrical negative lens 88a and the first cylindrical positive lens 88b are located at the center of the optical axis AX. It is configured to rotate integrally as a heart. Similarly, the second cylindrical negative lens 89a and the second cylindrical positive lens 89b are configured to rotate integrally about the optical axis AX. The first pair of cylindrical lenses 88 functions as a beam expander having power in the Z direction, and the second pair of cylindrical lenses 89 functions as a beam expander having power in the X direction. In this embodiment, the first cylindrical lens pair 88 and the second cylindrical lens pair 89 are set to have the same power. Therefore, the light beam that has passed through the first cylindrical lens pair 88 and the second cylindrical lens pair 89 is subjected to an expanding action by the same power in the Z direction and the X direction.

The light beam having passed through the afocal lens 85 is incident on the microlens array 8 as an optical integrator via the zoom lens 90 for changing the σ value. The position of the predetermined surface 86 is disposed at or near the front focal position of the zoom lens 90, and the incident surface of the microlens array 8 is disposed at or near the rear focal plane of the zoom lens 90. That is, the zoom lens 90 arranges the predetermined surface 86 and the entrance surface of the microlens array 8 substantially in a Fourier transform relationship, and thus optically connects the pupil plane of the afocal lens 85 and the entrance surface of the microlens array 8. Are arranged substantially conjugate. Therefore, on the entrance surface of the microlens array 8, for example, a ring-shaped illumination field centered on the optical axis 形成 is formed similarly to the pupil surface of the afocal lens 85. The overall shape of the annular illumination field changes similarly depending on the focal length of the zoom lens 90.

 FIG. 7 is a diagram for explaining the effect of the zoom lens 90 on a secondary light source formed in annular illumination. The annular secondary light source 130a formed in the standard state has a ring-shaped secondary light source whose overall shape is similarly enlarged by expanding the focal length of the zoom lens 90 to a predetermined minimum value. Change to light source 130c. That is, by the action of the zoom lens 90, both the width and the size (outer diameter) of the secondary light source in an annular shape change without changing the annular ratio.

The microlens array 8 is an optical element composed of a large number of microlenses having a positive refractive power arranged vertically and horizontally and densely. Each microlens constituting the microlens array 8 has the shape of the illuminated field to be formed on the mask M (and on the wafer W!). (Shape of exposure area to be formed). The light beam incident on the microlens array 8 is two-dimensionally split by a large number of microlenses, and the rear focal plane (and thus the illumination pupil) is substantially the same as the illumination field formed by the light beam incident on the microlens array 8 A secondary light source having a light intensity distribution, that is, a secondary light source consisting of a ring-shaped substantially planar light source around the optical axis AX is formed.

 The light flux from the annular secondary light source formed on the rear focal plane of the microlens array 8 is converted by a polarization monitor (for detecting the polarization state of the light illuminating the mask M (therefore, the wafer W)). The mask blind MB provided in the polarization state detecting means 50 is superimposedly illuminated via a beam splitter (optical path branching member) 51 and a condenser lens 9a.

 [0092] The mask blind MB as an illumination field stop has a rectangular illumination field corresponding to the shape and the focal length of each micro lens constituting the micro lens array 8. The light beam passing through the rectangular opening (light transmitting portion) of the mask blind MB is subjected to the condensing action of the imaging optical system 9b, and then passes through the mask (irradiation surface) M on which a predetermined pattern is formed. Illuminate in a superimposed manner. That is, the imaging optical system 9b forms an image of the rectangular opening of the mask blind MB on the mask M. The light flux transmitted through the pattern of the mask M forms an image of the mask pattern on the wafer W as a photosensitive substrate via the projection optical system PL. In this way, by performing batch exposure or scan exposure while driving and controlling the wafer W two-dimensionally in a plane orthogonal to the optical axis AX of the projection optical system PL, the pattern of the mask M is placed on each exposure area of the wafer W. Are sequentially exposed.

Note that the illumination conditions for the mask M as the surface to be illuminated and the imaging conditions for the ueno and the W as the photosensitive substrate can be automatically set according to, for example, the type of the pattern of the mask M. Here, the parameters for changing the illumination condition for the mask M include the 1 揷 2 wavelength plate's rotational angle position, insertion and removal of the debolizer 20, selection of the type of the diffractive optical element 4 a, and the phase member assembly 16. , The distance between the conical axicon system 87, the anisotropic scaling ratio of the first and second cylindrical lens pairs 88 and 89, the focal length of the zoom lens 90 for changing the σ value, and the like. The parameters for changing the imaging condition on the wafer W include the position and orientation of one or more optical elements in the projection optical system PL, the diameter of a variable aperture stop (not shown) in the projection optical system PL, and the like. Is mentioned. [0094] As described above, for example, in circular illumination or annular illumination, the polarized light whose vibration direction is the radial direction (radial direction) of the illumination area with respect to the traveling direction of the illumination light (exposure light). P-polarized light for the wafer W (mask M) and S-polarized light for which the oscillation direction is the circumferential direction of the illumination area with respect to the traveling direction of the illumination light (exposure light) are the S-polarized light for the wafer W (mask M). In this case, by performing S-polarized illumination, it is possible to improve the imaging performance of a pattern having a specific pitch direction and a narrow line width. Therefore, the illumination optical device according to the present embodiment includes a polarization monitor 50 for detecting whether or not the light illuminating the mask M (and, consequently, the wafer W) is in a desired S-polarized state, and whether or not a force is applied. You.

 FIG. 8 is a diagram showing a schematic configuration of a polarization monitor 50 including a beam splitter 51.

 As shown in FIG. 8, the light beam emitted from the microlens array 8 enters a beam splitter 51 provided in a polarization monitor 50. The beam splitter 51 has a form of a non-coated parallel flat plate (that is, elementary glass) formed of, for example, quartz glass. The light flux whose optical path force has been branched by being reflected by the beam splitter 51 enters the axicon mirror 52.

 [0096] Here, the axicon mirror 52 is configured by an optical element having an optical surface having, for example, a non-coated cone (in this embodiment, a cone), and the incident angle of the incident light is Brewster's angle. (Polarization angle). When the incident light is incident on the axicon mirror 52 at the Brewster angle, the S-polarized light component of the wafer W included in the incident light is reflected by the axicon mirror 52, and the P-polarized light of the Ueno and W included in the incident light is reflected. Are transmitted through the axicon mirror 52.

The light flux mainly composed of S-polarized light reflected by the axicon mirror 52 is collected by being reflected by the concave mirror 53 and reaches the light intensity detector 54. Here, the concave mirror 53 is constituted by a mirror (substantially elliptical mirror) having a substantially elliptical reflection surface for guiding light to the light intensity detector 54. Further, the optical paths between the axicon mirror 52 and the light intensity detector 54 are arranged opposite to each other with the optical axis AX between the laser light source 1 and the mask M interposed therebetween. The concave mirror 53 has a reflection surface formed of a multilayer film in order to guide the light flux reflected by the axicon mirror 52 to the light intensity detector 54 in a state where it is substantially preserved. As described above, the polarization state of the light beam reflected by the axicon mirror 52 and the polarization state of the light beam from the axicon mirror 52 reflected by the concave mirror 53 are substantially the same. Therefore, based on the output of the light intensity detector 54, the polarization state (the degree of S-polarized light with respect to the wafer W) and the light intensity of the light incident on the beam splitter 51 can be detected. Consequently, the polarization state (the degree of S-polarization with respect to the wafer _W ) and the light intensity of the illumination light that illuminates the mask M or the exposure light that reaches the wafer _W can be detected. Then, by adjusting the 1Z2 wave plate 10 and the deborizer 20 based on the detection result of the polarization monitor 50, it is possible to adjust the polarization state of the illumination light to the mask M to a desired S polarization state. Monkey

 [0099] According to the first embodiment, since the polarization monitor detects the polarization state and the light intensity of the light reflected by the conical axicon mirror, the light intensity distribution is formed around the illumination pupil. When performing annular shaped deformation illumination, the direction of polarization along the circumference of the circular area centered on the optical axis of the illumination optical device is the polarization direction. can do.

 For example, in annular illumination, the annular illumination shape formed at or near the illumination pupil is the shape shown in FIG. 3B, and the annular illumination shape 35 includes a plurality (eight in FIG. 3B) of illumination regions 35a. When the light passing through each of the illumination regions 35a-35h has a main component of linearly polarized light (indicated by a double-headed arrow in FIG. 3B) having a direction of polarization along the outer periphery of the annular illumination shape 35, having 35h. think of. Light passing through each of the illumination areas 35a-35h enters the reflection surface (optical surface) of the axicon mirror without changing the polarization state, and is reflected by the reflection surface in the same polarization state. The polarization state of light passing through regions 35a-35h can be accurately detected. Therefore, the mask can be illuminated with the optimal illumination light (exposure light) according to the pattern characteristics of the mask, and good exposure can be performed.

[0101] In the first embodiment, a light intensity detector for detecting the intensity (the intensity of all polarization components) of the light beam extracted by the beam splitter 51 is separately provided, and the output of the light intensity detector is controlled. From the output of the light intensity detector 54, it is possible to determine the ratio of S-polarized light to the wafer W in the illumination light for illuminating the mask M or the exposure light reaching the wafer W. Next, a second embodiment of the present invention will be described with reference to the drawings. The configuration of the exposure apparatus according to the second embodiment is such that the polarization monitor 50 of the exposure apparatus according to the first embodiment is changed to a polarization monitor 55. Therefore, in the description of the second embodiment, a detailed description of the same configuration as the configuration of the exposure apparatus working in the first embodiment will be omitted. In the description of the second embodiment, the same components as those of the exposure apparatus used in the first embodiment are denoted by the same reference numerals as those used in the first embodiment. Give an explanation.

 FIG. 9 is a diagram showing a schematic configuration of a polarization monitor 55 according to the second embodiment. As shown in FIG. 9, the light beam emitted from the microlens array 8 enters a beam splitter 51 provided in a polarization monitor 55. The light beam whose optical path force is also branched by being reflected by the beam splitter 51 enters the axicon mirror 52.

 Here, the axicon mirror 52 is arranged so that the incident angle of the incident light is incident at a Brewster angle (polarization angle) and at one or two of the two focal points of the concave mirror 53 described later. Are located. When the incident light is incident on the axicon mirror 52 at a Brewster angle, the S-polarized light component for the wafer W included in the incident light is reflected by the axicon mirror 52, and the P component for the wafer W included in the incident light is reflected. The polarized component passes through the axicon mirror 52.

The light flux mainly composed of S-polarized light reflected by the axicon mirror 52 is collected by being reflected by the concave mirror 53 and reaches the light intensity detector 54. Here, the concave mirror 53 is constituted by a mirror (substantially elliptical mirror) having a substantially elliptical reflecting surface for guiding light to the light intensity detector 54, and is decentered with respect to the optical axis of the axicon mirror 52. It is arranged in the state where it was set. In this embodiment, the concave mirror 53 is arranged in a state of being tilted with respect to the optical axis of the axicon mirror 52. Note that the concave mirror 53 may be arranged in a state shifted with respect to the optical axis of the axicon mirror 52. In addition, the light intensity detector 54 is disposed at one of the two focal points of the concave mirror 53 where the axicon mirror 52 is not disposed or in the vicinity thereof. The concave mirror 53 has a reflecting surface formed of a multilayer film in order to guide the light beam reflected by the axicon mirror 52 to the light intensity detector 54 in a state where it is substantially preserved. As described above, the polarization state of the light beam reflected by the axicon mirror 52 and the polarization state of the light beam from the axicon mirror 52 reflected by the concave mirror 53 are substantially the same. Therefore, based on the output of the light intensity detector 54, the polarization state (the degree of S-polarized light with respect to the wafer W) and the light intensity of the light incident on the beam splitter 51 can be detected. Consequently, the polarization state (the degree of S-polarization with respect to the wafer _W ) and the light intensity of the illumination light that illuminates the mask M or the exposure light that reaches the wafer _W can be detected. Then, by adjusting the 1Z2 wavelength plate 10 and the deborizer 120 based on the detection result of the polarization monitor 55, the state of the illumination light illuminating the mask M can be adjusted to a desired S-polarized state.

 According to the exposure apparatus of the second embodiment, the polarization monitor detects the polarization state and the light intensity of the light reflected by the axicon mirror having a conical shape. When performing annular illumination with a light intensity distribution around the periphery of the illumination optical device, the main component is S-polarized light whose polarization direction is the direction along the circumference of a circular region centered on the optical axis of the illumination optical device. It is possible to accurately detect the polarization state of the emitted light beam. Therefore, the mask can be illuminated with the optimum illumination light (exposure light) according to the pattern characteristics of the mask, and good exposure can be performed.

 [0108] Further, since the concave mirror provided in the polarization monitor can be arranged eccentrically with respect to the optical axis of the axicon mirror, the light reflected by the axicon mirror is focused at a desired position. Can be led to the light intensity detector, and the degree of freedom of arrangement of the axicon mirror and the light intensity detector can be improved.

 In the second embodiment as well, a light intensity detector for detecting the intensity of the light beam (the intensity of all polarization components) extracted by the beam splitter 51 is separately provided, and the light intensity corresponding to the output of the light intensity detector is provided. From the output of the intensity detector 54, it is possible to obtain the ratio of the S-polarized light to the wafer W in the illumination light for illuminating the mask M or the exposure light reaching the wafer W.

[0110] Next, a third embodiment of the present invention will be described with reference to the drawings. The configuration of the exposure apparatus according to the third embodiment is such that the polarization monitor 50 of the exposure apparatus according to the first embodiment is changed to a polarization monitor 57. Therefore, the third implementation form In the description of the embodiment, a detailed description of the same configuration as the configuration of the exposure apparatus working in the first embodiment will be omitted. In the description of the third embodiment, the same components as those of the exposure apparatus used in the first embodiment are denoted by the same reference numerals as those used in the first embodiment. Give an explanation.

 FIG. 10 is a diagram showing a schematic configuration of a polarization monitor 57 according to the third embodiment. As shown in FIG. 10, the light beam emitted from the microlens array 8 enters a beam splitter 51 provided in a polarization monitor 57. The light flux whose optical path force is also branched by being reflected by the beam splitter 51 enters the axicon mirror 59.

 Here, the axicon mirror 59 is composed of, for example, an optical element having a part of a non-coated cone (a cone in this embodiment), that is, an optical element having an optical surface having a shape with a reduced angle of the cone. ing. The axicon mirror 59 is disposed so that the incident angle of the incident light is incident at a Brewster angle (polarization angle), and at or near one of two focal points of a concave mirror 53 described later. When the incident light is incident on the axicon mirror 59 at Brewster's angle, the S-polarized light component for the Ueno and W contained in the incident light is reflected by the axicon mirror 59, and the P-polarized light component for the wafer W contained in the incident light. Transmits through the axicon mirror 59.

 The light flux mainly composed of S-polarized light reflected by the axicon mirror 59 is collected by being reflected by the concave mirror 53 and reaches the light intensity detector 54. Here, the concave mirror 53 is constituted by a mirror (substantially elliptical mirror) having a substantially elliptical reflecting surface for guiding light to the light intensity detector 54, and is decentered with respect to the optical axis of the axicon mirror 59. It is arranged in the state where it was set. In this embodiment, the concave mirror 53 is arranged in a state of being tilted with respect to the optical axis of the axicon mirror 59. Note that the concave mirror 53 may be arranged in a state shifted with respect to the optical axis of the axicon mirror 59. In addition, the light intensity detector 54 is disposed at one of the two focal points of the concave mirror 53 where the axicon mirror 59 is not disposed, or in the vicinity thereof.

[0114] The concave mirror 53 has a reflective surface formed of a multilayer film in order to guide the light flux reflected by the axicon mirror 52 to the light intensity detector 54 while substantially maintaining the polarization state. ing. As described above, the polarization state of the light beam reflected by the axicon mirror 59 and the polarization state of the light beam from the axicon mirror 59 reflected by the concave mirror 53 are configured to be substantially the same. Therefore, based on the output of the light intensity detector 54, the polarization state (the degree of S-polarized light with respect to the wafer W) and the light intensity of the light incident on the beam splitter 51 can be detected. Consequently, the polarization state (the degree of S-polarization with respect to the wafer _W ) and the light intensity of the illumination light that illuminates the mask M or the exposure light that reaches the wafer _W can be detected. Then, by adjusting the 1Z2 wavelength plate 10 and the deborizer 120 based on the detection result of the polarization monitor 57, the state of the illumination light illuminating the mask M can be adjusted to a desired S-polarized state.

 According to the exposure apparatus of the third embodiment, the polarization monitor has the polarization state and the light of the reflected light reflected by the axicon mirror having the optical surface having a partial shape of the cone. In order to detect the intensity, when performing annular illumination with a light intensity distribution around the illumination pupil, the direction along the circumference of the circular area centered on the optical axis of the illumination optical device is the polarization direction. It is possible to accurately detect the polarization state of a light beam mainly composed of S-polarized light.

 Further, since the light beam passes through an axicon mirror having an optical surface having a partial shape of a cone, the polarization state and light intensity of only the peripheral portion of the light beam are detected. In order to adjust the polarization state of light, it is practically sufficient to detect a portion corresponding to a light beam having a large numerical aperture (NA) of the illumination optical system, that is, a peripheral portion of the light beam. In addition, since it is not necessary to take in the entire light beam, the manufacture of the axicon mirror becomes easier, and the degree of freedom in the arrangement of the axicon mirror and the light intensity detector can be improved.

 [0118] Further, since the concave mirror provided in the polarization monitor can be arranged eccentrically with respect to the optical axis of the axicon mirror, the light reflected by the axicon mirror is condensed at a desired position. Can be led to the light intensity detector, and the degree of freedom of arrangement of the axicon mirror and the light intensity detector can be improved.

In the third embodiment as well, a light intensity detector for detecting the intensity of the light beam extracted by the beam splitter 51 (the intensity of all polarization components) is separately provided, and the output of the light intensity detector is controlled. From the output of the light intensity detector 54, the illumination light or C It is possible to determine the ratio of S-polarized light to wafer W in the exposure light reaching W.

 [0120] Next, a fourth embodiment of the present invention will be described with reference to the drawings. The configuration of the exposure apparatus according to the fourth embodiment is such that the polarization monitor 50 of the exposure apparatus according to the first embodiment is changed to a polarization monitor 60. Therefore, in the description of the fourth embodiment, a detailed description of the same configuration as the configuration of the exposure apparatus working in the first embodiment will be omitted. In the description of the fourth embodiment, the same components as those of the exposure apparatus used in the first embodiment are denoted by the same reference numerals as those used in the first embodiment. Give an explanation.

 FIG. 11 is a diagram showing a schematic configuration of a polarization monitor 60 according to the fourth embodiment. As shown in FIG. 11, the light beam emitted from the microlens array 8 enters a beam splitter 51 provided in a polarization monitor 60. The light beam whose optical path force is also branched by being reflected by the beam splitter 51 enters the axicon lens 62.

 Here, the axicon lens 62 has, for example, an uncoated cone (in this embodiment, a cone) shape, an optical surface 62a having a convex surface on the incident side, and a cone shape (this embodiment). In the embodiment, the optical element is provided with an optical surface 62b having a conical shape and having a concave (convex toward the incident side) on the exit side. The axicon lens 62 is arranged so that the incident angle of the incident light is incident on the optical surface 62a on the incident side at a Brewster angle (polarization angle)! When the incident light enters the optical surface (incident surface) 62a of the axicon lens 62 at a Brewster angle, the S-polarized light component contained in the incident light with respect to the wafer W is reflected by the incident surface 62a of the axicon lens 62. Then, the P-polarized light component of the wafer W included in the incident light is refracted by the incident surface 62a, and then passes through another optical surface (exit surface) 62b of the axicon lens 62. Injected from 62.

The luminous flux mainly containing P-polarized light transmitted through the axicon lens 62 is condensed by passing through the condenser lens 64 and reaches the light intensity detector 54. Here, each of the exit surface 62b of the axicon lens 62 and the lens surface of the condenser lens 64 has a light intensity detector in a state where the polarization state of the light beam transmitted through the entrance surface 62a of the axicon lens 62 is substantially preserved. In order to guide to 54, a coat formed of a multilayer film is provided. As described above, of the polarized light components of the light beam extracted by the beam splitter 51, the P-polarized light component for the wafer W is selectively extracted at the incident surface 62a of the axicon lens 62, and the extracted light component is transmitted to the light intensity detector 54. Since the light is guided, the polarization state of the light incident on the beam splitter 51 (the degree of P polarization with respect to the wafer W) can be detected based on the output of the light intensity detector. Although not shown, since a light intensity detector for detecting the intensity of the light beam extracted by the beam splitter 51 (the intensity of all polarization components) is separately provided, the output of the other light intensity detector is provided. If it is used, the degree of S polarization of the light incident on the beam splitter 51 with respect to the wafer W can be obtained. As a result, the polarization state (the degree of S-polarization with respect to the wafer W) and the light intensity of the illumination light that illuminates the mask M or the exposure light that reaches the wafer W can be detected. If a 1Z2 wave plate is arranged in the optical path between the beam splitter 51 and the axicon lens 62, the S-polarized light component for the wafer W can be converted to the P-polarized light component for the wafer W. The degree of S-polarization of the incident light with respect to the wafer W can be directly obtained. Then, by adjusting the 1Z2 wavelength plate 10 and the deborizer 20 based on the detection result of the polarization monitor 60, the state of the illumination light for illuminating the mask M can be adjusted to a desired S-polarized state.

 According to the exposure apparatus of the fourth embodiment, the polarization monitor detects the polarization state and the light intensity of the transmitted light transmitted through the axicon lens having the conical optical surface. Therefore, when performing annular illumination with a light intensity distribution around the illumination pupil, S-polarized light whose polarization direction is the direction along the circumference of the circular area centered on the optical axis of the illumination optical device is used. The polarization state of the light beam as the main component can be accurately detected. Therefore, the mask can be illuminated with the optimal illumination light (exposure light) according to the pattern characteristics of the mask, and good exposure can be performed.

In each of the above-described embodiments, the 1Z2 wavelength plate 10 as a phase member for changing the polarization plane of the incident linearly polarized light as necessary is disposed on the light source side and is incident. A deborrizer 20 for depolarizing the linearly polarized light as needed is arranged on the mask side. However, without being limited to this, the same optical function and effect can be obtained by disposing the deborizer 20 on the light source side and disposing the 1Z2 wave plate 10 on the mask side. In each of the above embodiments, the quartz prism 20b is used as a compensator for compensating the traveling direction of light via the quartz prism 20a. However, the present invention is not limited to this. A wedge-shaped prism formed of quartz, fluorite, or the like, which is highly durable to KrF excimer laser light or ArF excimer laser light, is used as a compensator. You can also.

 In each of the above embodiments, the polarization state is detected using the reflected light of the beam splitter, but the illumination light is directly transmitted to the axicon mirror or the axicon lens without passing through the beam splitter. It can also be arranged to be incident. In this case, the polarization state of the illumination light can be detected with higher accuracy without being affected by the polarization fluctuation due to the polarization characteristics of the beam splitter.

 In each of the above embodiments, the reflected light of the beam splitter is received by the axicon mirror or the axicon lens to detect the polarization state. However, when the polarization monitor is incorporated in the illumination optical device, In some cases, a folding mirror or the like must be interposed for convenience of arrangement. In this case, the direction of the reflected light extracted from the beam splitter is set to the direction orthogonal to the optical axis AX, and the angle at which the light beam is bent by the bending mirror or the like is set at a right angle. It is possible to reduce the change in the polarization state caused by the presence of the light. If the change in the polarization state caused by the interposition of the folding mirror is known, the change in the polarization state caused by the interposition of the folding mirror can be reduced by adjusting the offset as an offset amount. it can.

 Further, in each of the above-described embodiments, a power pyramid or a pyramid using an axicon mirror or an axicon lens having an optical surface having a conical shape or a partial shape of a cone is used. An axicon mirror or an axicon lens provided with an optical surface having the shape of a part may be used.

In each of the above embodiments, the polarization monitor detects the light flux incident on the beam splitter, that is, the polarization state and light intensity of the illumination light illuminating the mask, but actually illuminates the wafer. The polarization state of the emitted light is important. Polarization monitoring force A change in the polarization state of the light beam may occur in the optical path to the wafer. Specifically, the optical system from the S-beam splitter to the wafer (part of the illumination optical system and the projection optical system) There is a case where the polarization state changes due to the passage. When a change occurs in the polarization state of the light beam, the detection result of the polarization monitor is paired with the detection result of the wafer surface polarization monitor newly installed to detect the polarization state and light intensity of the light illuminating the wafer. It is necessary to detect the response.

 FIG. 12 is a diagram showing a schematic configuration of a wafer surface polarization monitor 70 for detecting the polarization state and light intensity of light illuminating the wafer W. As shown in FIG. 12, the wafer surface polarization monitor 70 is attached to a side of a wafer stage (not shown) on which the wafer W is mounted. The light beam passing through the illumination optical device, the mask M, and the projection optical system PL shown in FIG. Here, the condensing optical system 72 is arranged such that the image plane position S of the projection optical system PL or its vicinity is the front focal position. Therefore, the light beam condensed by the projection optical system PL is converted into a substantially parallel light beam via the light condensing optical system 72.

 The light beam that has passed through the condensing optical system 72 is sequentially reflected by the axicon mirror 73 and the concave mirror 74 of the wafer surface polarization monitor 70, and reaches the light intensity detector 75. The configuration and operation of the axicon mirror 73, the concave mirror 74, and the light intensity detector 75 are the same as those of the axicon mirror 52, the concave mirror 53, and the light intensity detector 54 included in the polarization monitor 55 according to the second embodiment. The detailed description is omitted because it has the configuration and operation described above. An offset value is calculated based on the detection result of the polarization monitor that works in each of the above-described embodiments and the detection result of the wafer surface polarization monitor 70, and is calculated as the detection result of the polarization monitor that works in each of the above-described embodiments. The polarization state and light intensity are corrected by adding the offset values. Note that the configuration of the wafer surface polarization monitor may have the same configuration as the polarization monitor according to the first, third, or fourth embodiment.

 Further, in each of the above-described embodiments, when performing non-polarized illumination, the phase member assembly 16 also retreats the illumination optical path force. However, even if non-polarized light passes through the phase member assembly 16, Since the light remains polarized, it does not have to be retracted.

Further, by changing the rotation angle of the 1Z2 wavelength plate 10 and rotating the plane of polarization of linearly polarized light to the phase member assembly 16 by 90 degrees, the polarization state of the light beam passing through the phase member assembly 16 is changed.ゥ S-polarization power for ENO and W can also be switched to P-polarization for wafer W. Further, in each of the above-described embodiments, an example is shown in which S-polarized light for wafer W is combined with circular illumination or annular illumination. S-polarized light for wafer W and multi-pole such as dipole or quadrupole are used. It can be combined with lighting.

 In each of the above embodiments, an optical surface having a conical shape or a partial shape of a conical shape is used as polarization selecting means for selecting light of a circumferentially polarized component or light of a radial direction component from a light beam. Although an optical element having a polarizer is used, at least one of the optical element and the polarizer may be rotatable around an optical axis.

 Next, with reference to the drawings, a description will be given of a wafer surface polarization monitor 100 using a phase shifter and a polarizer at least one of which is rotatable around an optical axis as polarization selection means. FIG. 13 is a diagram showing a schematic configuration of a wafer surface polarization monitor 100 for detecting the polarization state and light intensity of light illuminating the wafer W. As shown in FIG. 13, the wafer surface polarization monitor 100 includes a pinhole member 91 that can be positioned at or near the position of the wafer W. When the wafer surface polarization monitor 100 is used, the optical path force of the wafer W is also retracted. The light that has passed through the pinhole 91a of the pinhole member 91 is arranged such that the image plane position S of the projection optical system PL or its vicinity is the front focal position, and is converted into a substantially parallel light beam through the collimating lens 92. After being reflected by the reflecting mirror 93, the light enters the relay lens system 94. The substantially parallel light beam passing through the relay lens system 94 passes through a λ / 4 plate 95 as a phase shifter and a polarizing beam splitter 96 as a polarizer, and then reaches a detection surface 97a of a two-dimensional CCD 97. Here, the detection surface 97a of the two-dimensional CCD 97 is almost optically conjugate with the exit pupil of the projection optical system PL, and is almost optically conjugate with the illumination pupil plane of the illumination optical device.

The λ] 4 plate 95 is configured to be rotatable about the optical axis, and a setting unit 98 for setting a rotation angle about the optical axis is connected to the λΖ4 plate 95. ing. Thus, when the degree of polarization of the illumination light with respect to the wafer W is not 0, the light intensity on the detection surface 97a of the two-dimensional CCD 97 is rotated by rotating the λλ4 plate 95 around the optical axis via the setting unit 98. The distribution changes. Therefore, the wafer surface polarization monitor 100 detects the change in the light intensity distribution on the detection surface 97a while rotating the λ Ζ4 plate 95 around the optical axis using the setting unit 98, and the detection result is obtained by the power transfer method. Measuring the polarization state of illumination light it can.

 [0140] The rotation retarder method is described in detail, for example, by Tsuruta, "Applied Optics for Optical Pencil-Optical Engineers", New Technology Communications Inc., and the like. Actually, the polarization state of the illumination light at a plurality of positions in the wafer surface is measured while the pinhole member 90 (and thus the pinhole 90a) is moved two-dimensionally along the wafer surface. At this time, since the wafer surface polarization monitor 100 detects a change in the light intensity distribution on the two-dimensional detection surface 97a, the distribution of the polarization state in the pupil of the illumination light is measured based on the detected distribution information. can do.

 [0141] Specifically, the processing unit 99 controls the relative rotation between the output from the two-dimensional CCD 97 and the λ / 4 plate 95 as a phase shifter and the polarization beam splitter 96 as a polarizer from the setting unit 98. Given the information about the angle, the two-dimensional distribution of horizontal linear intensity minus vertical linear polarization intensity S1, the two-dimensional distribution of 45-degree linear polarization intensity minus 135-degree linear polarization S2, and the clockwise circle Calculate the two-dimensional distribution of the polarization intensity minus the left-handed circular polarization intensity S3.

 [0142] The two-dimensional distribution of the horizontal linear polarization intensity minus the vertical linear polarization intensity S1 with respect to the total intensity SO (the two-dimensional distribution of S1ZS0) and the 45-degree linear polarization intensity minus the 135-degree linear polarization with respect to the total intensity SO Find the two-dimensional distribution of intensity S2 (two-dimensional distribution of S2ZS0). Next, the two-dimensional distribution of S1ZS0 is equally divided in the circumferential direction of the circle centered on the center point of the distribution, and the two-dimensional distribution of S2ZS0 is divided equally in the circumferential direction of the circle centered on the center point of the distribution. Into equal parts.

FIG. 14 shows an example of a region equally divided in the circumferential direction. In the example of FIG. 14, the area is equally divided into eight areas 101a and 101h. Here, focusing on the regions 101a and 101e, the polarization plane of the circumferential polarization component in these regions 101a and 101e can be approximated to the horizontal direction which is the tangential direction of the circumference in the regions 101a and 101e. Focusing on the regions 101c and lOlg, the polarization plane of the circumferential polarization component in these regions 101c and lOlg can be approximated to the vertical direction which is the tangential direction of the circumference in the regions 101c and lOlg. Similarly, when focusing on the regions 101d and 101h, the polarization planes of the circumferential polarization components in these regions 101d and 101h can be approximated in the 45-degree direction, and when focusing on the regions 101b and lOlf, these regions 101b and lOlf have Circumferential deviation The polarization plane of the light component can be approximated in the direction of 135 degrees.

Therefore, the regions 101a and 101e and the regions 101c and 101g are cut out from the two-dimensional distribution of S1ZSO, and the values of SlZSO in the regions 101a, 101e and 101c and 101g are obtained, and the values of S2 / S0 are obtained. The dimensional distribution force also cuts out the regions 101b and 101f and the regions 101d and 101h, and S2 in these regions 101b and 101f and the regions 101d and 101h.

By determining the value of Zso, it is possible to evaluate the polarization state of a light beam mainly composed of S-polarized light whose polarization direction is the direction along the circumference of a circular region centered on the optical axis of the illumination optical device.

 In the above example, the distribution of the polarization state (such as the two-dimensional distribution of S1ZS0 and the two-dimensional distribution of S2ZS0) is divided into eight in the circumferential direction. However, the number of divisions may be increased as necessary. It may be divided, or it may be divided into four or two.

 [0146] As described above, in the wafer surface polarization monitor 100, the detection surface 97a of the two-dimensional CCD 97 is disposed on a surface optically substantially conjugate to the illumination pupil surface of the illumination optical device. The distribution of the polarization state (2D distribution of S1ZS0, 2D distribution of S2ZS0, etc.) can be measured.

 Meanwhile, in the wafer surface polarization monitor 100, a λ / 2 plate can be used as a retarder instead of the λ と し て 4 plate 95. Regardless of the type of phase shifter used, to measure the polarization state, that is, the four status parameters, the relative position of the phase shifter and the polarizer (polarizing beam splitter 96) around the optical axis is required. It is necessary to detect a change in the light intensity distribution on the detection surface 97a in at least four different states by changing the angle or by retracting the phase shifter or polarizer from the optical path. In this embodiment, the λZ4 plate 95 as a phase shifter is rotated around the optical axis. However, it is possible to rotate the polarizing beam splitter 96 as a polarizer around the optical axis. Both children may be rotated around the optical axis. Also, instead of or in addition to this operation, if one or both of the λ / 4 plate 95 as a phase shifter and the polarizing beam splitter 96 as a polarizer are also removed from the optical path. good.

In the wafer surface polarization monitor 100, the polarization state of light may change due to the polarization characteristics of the reflection mirror 93. In this case, since the polarization characteristics of the reflector 93 have been preliminarily increased, the wafer is calculated based on the influence of the polarization characteristics of the reflector 93 on the polarization state by a necessary calculation. By correcting the measurement result of the plane polarization monitor 100, the polarization state of the illumination light can be accurately measured. In addition, even when the polarization state changes due to other optical components such as a lens as well as the reflection mirror, the measurement result of the wafer surface polarization monitor 100 is similarly corrected to accurately measure the polarization state of the illumination light. be able to.

 [0149] In the above example, the circumferential polarization state is detected, but the radial polarization state may be detected.

 In each of the above-described embodiments, KrF excimer laser light (wavelength: 248 ηm) or ArF excimer laser light (wavelength: 193 nm) is used as exposure light, but this is not a limitation. Other suitable laser light source, such as an F laser that supplies laser light with a wavelength of 157 nm

 The present invention can also be applied to a light source other than a two-light source or a laser light source, such as a lamp light source that supplies ultraviolet light such as i-line, g-line, and h-line. Further, in each of the above-described embodiments, the present invention has been described by taking the projection exposure apparatus having the illumination optical device as an example. However, the present invention is applied to a general illumination optical apparatus for illuminating an irradiation surface other than a mask. It is clear that can be applied.

 In each of the above-described embodiments, a technique of filling the optical path between the projection optical system and the photosensitive substrate with a medium (typically, a liquid) having a refractive index greater than 1.1, a so-called technique. The immersion method may be applied. In this case, as a method of filling the liquid in the optical path between the projection optical system and the photosensitive substrate, a method of locally filling the liquid as disclosed in International Publication No. WO99Z49504, a special method, or the like. A method of moving a stage holding a substrate to be exposed as disclosed in Japanese Unexamined Patent Application Publication No. 6-124873 in a liquid tank, and a stage disclosed in Japanese Patent Application Laid-Open No. 10-303114. A method in which a liquid tank having a predetermined depth is formed thereon and the substrate is held therein can be employed.

 [0152] As the liquid, it is preferable to use a liquid that has transparency to exposure light and a refractive index that is as high as possible, or a liquid that is stable to the photoresist applied to the substrate surface. For example, when KrF excimer laser light or ArF excimer laser light is used as the exposure light, pure water or deionized water can be used as the liquid. When the F laser beam is used as the exposure light, the liquid is, for example, a fluorine-based material that can transmit the F laser beam.

twenty two

Use a fluorinated liquid such as perfluoropolyether (PFPE)! /. [0153] Further, as disclosed in JP-A-10-163099, JP-A-10-214783, JP-T-2000-505958, and the like, separate substrates to be processed such as wafers are disclosed. It can also be applied to a twin-stage type exposure device equipped with two stages that can be mounted on the XY-axis and move independently in the X and Y directions.

 [0154] In the exposure apparatus that works in each of the above embodiments, the mask (retinal) is illuminated by the illumination optical device (illumination step), and the transfer pattern formed on the mask is projected using the projection optical system. By exposing a photosensitive substrate (wafer) (exposure step), a micro device (semiconductor element, imaging element, liquid crystal display element, thin-film magnetic head, etc.) can be manufactured. Hereinafter, an example of a method for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using an exposure apparatus that is powerful in the above-described embodiment will be described. This will be described with reference to the flowchart of FIG.

 First, in step S301 in FIG. 15, a metal film is deposited on one lot of wafers.

 In the next step S302, a photoresist is coated on the metal film on the wafer of the lot. Thereafter, in step S303, using the exposure apparatus according to the above-described embodiment, an image of the pattern on the mask is sequentially exposed and transferred to each shot area on the wafer of the lot through the projection optical system. . Thereafter, in step S304, the photoresist on the one-lot wafer is developed, and then in step S305, the resist is etched on the one-port wafer using the resist pattern as a mask, thereby forming the photoresist on the mask. Circuit pattern force S corresponding to the pattern of each, formed in each shot area on each wafer

After that, a device such as a semiconductor element is manufactured by forming a circuit pattern of a further upper layer and the like. According to the above-described semiconductor device manufacturing method, since exposure is performed using illumination light (exposure light) having an optimal polarization state corresponding to the characteristics of a circuit pattern, a semiconductor device having an extremely fine circuit pattern can be accurately and accurately formed. Throughput can be obtained well. In step S301 to step S305, a metal is vapor-deposited on the wafer, a resist is applied on the metal film, and each of the steps of exposure, development, and etching is performed. After the silicon oxide film is formed on the silicon oxide film, a resist is applied on the silicon oxide film, and the steps of exposure, development, etching, and the like are performed. You can do it, you don't have to.

 [0157] Further, in the exposure apparatus that is active in the above-described embodiment, a liquid crystal display element as a micro device is obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). You can also. Hereinafter, an example of the technique at this time will be described with reference to the flowchart in FIG. In FIG. 16, in a pattern forming step S401, a so-called optical lithography method in which a mask pattern is transferred and exposed to a photosensitive substrate (a glass substrate coated with a resist, etc.) using an exposure apparatus that is powerful in the above-described embodiment. The process is executed. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate is subjected to a development process, an etching process, a resist stripping process and the like to form a predetermined pattern on the substrate, and the process proceeds to the next color filter forming process S402.

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

 Thereafter, in a module assembling step S404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method of manufacturing a liquid crystal display element, since exposure is performed using illumination light (exposure light) having an optimum polarization state corresponding to the characteristics of the circuit pattern, a liquid crystal display element having an extremely fine circuit pattern can be obtained. High accuracy and high throughput can be obtained.

[0160] According to the illumination optical device of the present invention, the polarization state detecting means has a cone shape or a cone shape. Since an optical element having an optical surface having a partial shape is provided, the optical axis of the illumination optical device is used when performing annular illumination or quadrupole illumination having a light intensity distribution around the illumination pupil. It is possible to accurately detect the polarization state of a light beam mainly composed of linearly polarized light whose polarization direction is a direction along the circumference of a circular region centered at.

 [0161] Further, since the polarization state of the light beam extracted by the optical path branching member and the light beam passing through the optical element are substantially the same, the light source unit emits light by detecting the polarization state of the light beam passing through the optical element. The polarization state of the light beam illuminating the surface to be irradiated can be accurately detected.

 [0162] Also, of the illumination light applied to the surface to be illuminated, the illumination light applied to the surface to be illuminated within a specific incident angle range is converted into light of a polarization state mainly composed of S-polarized light with respect to the surface to be illuminated. Since the S-polarized light generating means is provided, the surface to be irradiated can be irradiated with illumination light having high contrast.

 [0163] The illumination light passing through at least a part of the specific annular zone, which is a predetermined annular zone around the optical axis, is linearly polarized with the circumferential direction of the specific annular zone as the polarization direction. Is provided, the surface to be illuminated can be illuminated with illumination light having a high contrast.

 Further, according to the exposure apparatus of the present invention, since the illumination optical apparatus of the present invention is provided, it is possible to perform illumination with light having an optimal polarization state corresponding to the characteristics of the pattern of the mask. Exposure can be performed.

 Further, according to the exposure method of the present invention, since the illumination of the mask is performed using the illumination optical device of the present invention, the illumination is performed with light having an optimum polarization state corresponding to the characteristic of the turn of the mask. And good exposure can be performed.

 Industrial applicability

As described above, the illumination optical device, the polarization state detector, the exposure apparatus, and the exposure method of the present invention are suitable for use in manufacturing micro devices such as semiconductor devices, liquid crystal display devices, and thin film magnetic heads. I have.

Claims

The scope of the claims  [1] In an illumination optical device that illuminates an irradiated surface with light from a light source unit,  A polarization state detection unit for detecting a polarization state of a light beam traveling along an optical path between the light source unit and the irradiated surface;  An optical element having an optical surface having a cone shape or a partial shape of a cone,  A light intensity detector for detecting the intensity of light passing through the optical element;  An illumination optical device, comprising:  [2] The polarization state detecting means is provided in the optical path between the light source unit and the irradiated surface, and includes an optical path branching member for branching a light beam traveling in the optical path from the optical path. 2. The illumination optical device according to claim 1, wherein the illumination optical device is provided.  [3] The polarization state of light passing through the optical surface of the optical element and the polarization state of a light beam reaching the light intensity detector after passing through the optical element are substantially the same. 3. The illumination optical device according to claim 1 or claim 2.  [4] The polarization state detection means is disposed in an optical path between the optical surface of the optical element and the light intensity detector, and the polarization state of the light beam extracted by the optical path branching member, 4. The illumination optical device according to claim 2, further comprising a film having a function of making the polarization state of the light beam from the optical path branching member through the optical element substantially the same as the polarization state.  5. The illumination optical device according to claim 4, wherein the film includes a multilayer film. 6. The method according to claim 1, wherein the polarization state detecting means further includes a concave mirror that condenses the reflected light via the optical element and guides the reflected light to the light intensity detector. The illumination optical device according to claim 1. 7. The illumination optical device according to claim 6, wherein the concave mirror is disposed so as to be decentered with respect to an optical axis of the optical element. [8] The optical device according to claim 1, wherein the optical element and the light intensity detector are arranged opposite to each other at a position sandwiching the optical path between the light source unit and the illuminated surface. The illumination optical device according to claim 7. [9] The polarization state detecting means further comprises a light condensing optical system for condensing light transmitted through the optical element and guiding the light to the light intensity detector. Item 6. The illumination optical device according to any one of items 5.  10. The illumination optical device according to claim 9, wherein the light collecting optical system includes a lens.  11. The illumination optical device according to claim 9, wherein the optical element includes another optical surface having a cone shape or a partial shape of the cone.  12. The illumination optical device according to claim 11, wherein the optical surface of the optical element is a convex surface, and the another optical surface is a concave surface.  13. The optical element, wherein the optical element is arranged so that the optical surface having the convex surface and the another optical surface having the concave surface are located in order from the light incident side. 13. The illumination optical device according to 12.  [14] An S-polarized light generating unit disposed in an optical path between the light source unit and the surface to be illuminated, wherein the S-polarized light generating unit applies light to the surface to be illuminated based on a light beam from the light source unit. In the illumination light to be irradiated, a light beam irradiated to the surface to be illuminated within a specific incident angle range is generated as light in a polarization state having S-polarized light as a main component with respect to the surface to be illuminated. The illumination optical device according to claim 1, wherein  [15] a circumferentially polarized light generating means disposed in an optical path between the light source unit and the irradiated surface;  The circumferential direction polarized light generation means is configured to determine, based on a light beam from the light source unit, a predetermined annular zone centered on the optical axis of the illumination optical device in a pupil plane of the illumination optical device or a surface in the vicinity thereof. The illumination light passing through at least a part of the specific orbicular zone is generated as light in a polarization state mainly composed of linearly polarized light whose polarization direction is the circumferential direction of the specific orbicular zone. The illumination optical device according to any one of claims 1 to 13, wherein: 16. The optical device according to claim 14, wherein the optical element is disposed in an optical path between the S-polarized light generating means or the circumferentially polarized light generating means and the light intensity detector. 15. The illumination optical device according to 15. 17. The method according to claim 1, wherein the cone shape or a partial shape of the cone has a conical shape or a partial shape of a cone. Lighting optics.  18. The illumination according to any one of claims 1 to 16, wherein the pyramidal shape or a part of the decay has a pyramidal shape or a partial shape of a pyramid. Optical device.  [19] In an exposure apparatus that transfers a mask pattern onto a photosensitive substrate,  An illumination optical device according to any one of claims 1 to 18 for illuminating the mask,  A projection optical system for forming an image of the pattern of the mask on the photosensitive substrate. [20] An exposure method for transferring a predetermined pattern onto a photosensitive substrate!  An illumination step of illuminating a mask on which the predetermined pattern is formed using the illumination optical device according to any one of claims 1 to 18.  A transfer step of transferring the predetermined pattern onto the photosensitive substrate;  An exposure method comprising: [21] A polarization state applied to an illumination optical device that illuminates a surface to be illuminated with light of a light source unit, and for detecting a polarization state of a light beam traveling in an optical path between the light source unit and the surface to be illuminated. In the detector,  Polarization selecting means for selecting light of a circumferential polarization component or light of a radial polarization component from the light beam,  A light intensity detector that detects the light of the circumferential polarization component or the light of the radial polarization component selected by the polarization selection unit;  A polarization state detector comprising: 22. The polarization state detector according to claim 21, wherein the polarization selecting means includes an optical element having an optical surface having a cone shape or a partial shape of the cone shape. 23. The polarization state detector according to claim 22, further comprising a concave mirror that collects reflected light via the optical element and guides the reflected light to the light intensity detector. 24. The polarization state detector according to claim 22, further comprising a condensing optical system that condenses the light transmitted through the optical element and guides the light to the light intensity detector.  25. The method according to claim 21, wherein the cone shape or a part of the cone shape has a conical shape or a partial shape of a cone. Polarization state detector.  26. The method according to any one of claims 21 to 24, wherein the pyramid shape or a part of the pyramid shape has a pyramidal shape or a part of a pyramid shape. Polarization state detector. [27] The polarization selecting means includes a phase shifter and a polarizer,  22. The exposure apparatus according to claim 21, wherein at least one of the phase shifter and the polarizer is configured to be rotatable about an optical axis. 28. The polarization state detection according to claim 27, further comprising setting means for setting at least four states in which the relative rotation angles of the phase shifter and the polarizer are different. vessel.  [29] The light intensity detector is disposed on a plane optically substantially conjugate with an illumination pupil plane of the illumination optical device, and detects a light intensity distribution on a plane optically substantially conjugate with the illumination pupil plane. The polarization state detector according to claim 27 or claim 28.  [30] The apparatus further comprises processing means for processing an output from the light intensity detector,  The processing unit is configured to determine whether the light of the circumferential polarization component or the light of the circumferential polarization component is based on information on a relative rotation angle between the phase shifter and the polarizer and information on the light intensity distribution obtained by the light intensity detector. 30. The polarization state detector according to claim 29, wherein the state of light of the radial polarization component is output.  [31] The polarization state detector is arranged in the illumination optical device, and is branched by an optical path branching member for branching a light beam traveling from the light source unit along the optical path of the irradiated surface from the optical path. The polarization state detector according to any one of claims 21 to 30, wherein the polarization state detector is arranged in an optical path of a light beam.  [32] In an illumination optical device that illuminates an irradiated surface with light from a light source unit, A polarization state detector according to any one of claims 21 to 31, An optical path branching member for branching a light beam traveling along an optical path between the light source unit and the irradiated surface from the optical path;  An illumination optical device, comprising:  [33] In an exposure apparatus that transfers a mask pattern onto a photosensitive substrate,  An illumination optical device according to claim 32 for illuminating the mask,  A projection optical system for forming an image of the pattern of the mask on the photosensitive substrate. [34] An exposure method for transferring a mask pattern onto a photosensitive substrate!  An illumination step of illuminating a mask on which the predetermined pattern is formed using the illumination optical device according to claim 32,  A transfer step of transferring the predetermined pattern onto the photosensitive substrate;  An exposure method comprising: [35] An exposure method for transferring a mask pattern onto a photosensitive substrate!  An illumination step of illuminating a mask on which the predetermined pattern is formed;  A transfer step of transferring the predetermined pattern onto the photosensitive substrate,  A polarization state detection step of detecting a polarization state of a light beam directed toward the mask or the photosensitive substrate using the polarization state detector according to any one of claims 21 to 31.  An exposure method comprising: