JP2003059799A - Illumination optical system, exposure system, and method of manufacturing microdevice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure system provided with a location measuring device which does not require so much accuracy for adjustment of an optical system and measures the location using laser light having a short wavelength. SOLUTION: A light source 1 emits laser light having a wavelength of 200 nm or shorter such as ArF excimer laser (193 nm) and F2 laser (157 nm). A TTR sensor 2 observes a reticle alignment mark RM formed on a reticle R, and a wafer alignment mark WM formed on a wafer W via a projection optical system PL or a reference mark formed on a reference member 14, and detects relative positions of these marks. A first rod lens 24 and a second rod lens 26 for guiding the laser light emitted from the light source 1 to the TTR sensor 20 are also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical system, an exposure apparatus, and a microdevice which are mainly used in manufacturing a microdevice such as a semiconductor device, an image pickup device, a liquid crystal display device, or a thin film magnetic head in a lithography process. Manufacturing method.

[0002]

2. Description of the Related Art Semiconductor devices, image pickup devices, liquid crystal display devices,
In the photolithography process, which is one of the manufacturing processes of thin-film magnetic heads and other microdevices, a pattern formed on a mask or reticle (hereinafter collectively referred to as a mask) is treated with a photosensitive agent such as photoresist. There is used an exposure apparatus that transfers a wafer, a glass plate, or the like coated with (hereinafter, referred to as a substrate when they are collectively referred to). For example, when manufacturing a semiconductor element, a step-and-repeat type reduction projection exposure apparatus (so-called stepper) is often used. This stepper exposes a pattern of semiconductor elements formed on a reticle onto a predetermined area (shot area) of a wafer, and then steps the stage on which the wafer is mounted by a certain distance to move to another shot area. Is exposed, and this operation is repeated for all shot areas set on the wafer to transfer the image of the pattern formed on the reticle to the entire wafer.

When the shot area set on the wafer is exposed by using this stepper, the position where the image of the pattern formed on the reticle is projected and the position of the shot area where the exposure is performed are accurately aligned. There is a need. In particular, a semiconductor device is manufactured by performing exposure processing several times to several tens of times in a lithography process, and thus alignment must be performed with high accuracy. Further, in recent years, there has been an increasing demand for miniaturization of patterns formed on semiconductor elements, and it has been required to improve alignment accuracy in order to manufacture semiconductor elements having desired performance. For example, a CPU (central processing unit), which is one of semiconductor elements, is manufactured according to a process rule of about 0.18 μm, but it is predicted that further miniaturization will be achieved in the future.

The exposure apparatus moves the stage with the wafer placed on the stage, thereby performing relative alignment between the image position of the pattern projected on the wafer and the position of the shot area to be exposed. Therefore, in order to improve the accuracy of alignment, first, the projection position of the pattern image in the coordinate system provided for the stage (this coordinate system moves the origin position along with the movement of the stage) is highly accurate. Need to be detected in. Therefore, the exposure apparatus uses a TTL (through-the-lens) type alignment sensor or a projection sensor that measures position information of a reference mark formed on a reference member provided at one end of the stage via a projection optical system. A TTR (through the reticle) type alignment sensor is provided which simultaneously observes the reference mark and the reticle mark formed on the reticle via an optical system and measures the relative positional relationship between the two.

Further, in order to meet the demand for miniaturization of patterns formed on semiconductor elements, it is necessary to increase the resolution of the exposure apparatus. In order to increase the resolution of the image of the pattern projected on the wafer, the exposure apparatus shortens the wavelength of the illumination light emitted from the illumination optical system that illuminates the reticle,
Moreover, the numerical aperture (NA) of the projection optical system for projecting the image of the pattern formed on the reticle onto the wafer is designed to be high. Furthermore, when the illumination light emitted to the wafer has an illuminance distribution, the line width of the pattern formed on the wafer changes. Therefore, in order to form a pattern with a uniform line width, the illumination light illuminance distribution Need to be uniform.

[0006]

By the way, it is necessary to illuminate the reference mark in order to measure the position information of the reference mark formed on the reference member provided at one end of the stage using the above-mentioned alignment sensor. However, as the light for illuminating the reference mark, a part of the illumination light with which the reticle is irradiated is used. This is to prevent a detection error due to the aberration generated in the projection optical system. In other words, the projection optical system is set so that various aberrations are minimized at the wavelength of the illumination light that illuminates the reticle. Is caused.

Conventionally, in the illumination optical system, a part of the light emitted from the light source is branched and guided below the reference member using an optical fiber to illuminate the reference mark from below the reference member, or A fiber is used to guide the branched light to an alignment optical system provided above or below the reticle to illuminate the reference mark via the projection optical system.
However, if the wavelength of the illumination light is shortened (for example, 200 nm or less) from the above demand for higher resolution, the absorption increases in the conventionally used silica-based optical fiber. Alternatively, there arises a problem that it cannot be used for applications leading to an alignment optical system.

If a relay optical system for relaying the light branched by the illumination optical system is provided, it can be guided to below the reference member or to the alignment optical system without using an optical fiber. However, since the optical fiber used conventionally has flexibility, the optical fiber can be arranged in accordance with the arrangement of the constituent members constituting the exposure apparatus, whereas the relay optical system constitutes the exposure apparatus. If the optical path is set according to the arrangement of the constituent members, the number of optical members increases and the adjustment becomes difficult. Further, in order to improve the detection accuracy of the alignment optical system, the arrangement of these optical members must be adjusted with high accuracy. For example, when the optical axis of the alignment optical system with respect to the reference member is tilted, the reference mark formed on the reference member is laterally displaced and detected according to the height position of the reference member. Therefore, in order to maintain high detection accuracy of the alignment optical system when an optical fiber for guiding light to the alignment optical system cannot be used, not only the position of the relay alignment optical system but also the position of the optical member forming the relay optical system is used. It is necessary to perform adjustment with high accuracy, and there is a problem that the manufacturing cost of the exposure apparatus including the cost required for adjustment increases.

Further, in order to shorten the wavelength of the illumination light, the exposure apparatus is provided with a laser light source such as an excimer laser, but the laser light emitted from the laser light source is narrowed in order to eliminate aberrations in the projection optical system PL as much as possible. There is a problem that speckle occurs when it is banded. Here, the speckle is an irregular bright and dark small spot pattern with high contrast. If the speckles are generated, an illumination distribution is generated in the illumination light with which the reticle is irradiated, and further with the light with which the wafer is irradiated, which is not preferable for forming a fine pattern having a uniform line width. Further, when part of the light emitted from the laser light source is used as the light for illuminating the reference pattern formed on the reference member, if speckles occur, there is a problem that the detection accuracy is lowered.

The present invention has been made in view of the above circumstances, and it is a first object of the present invention to provide an illumination optical system capable of obtaining illumination light having a uniform illuminance distribution even when a short wavelength light source is used. The purpose of 1. A second object of the present invention is to provide an exposure apparatus provided with an illumination optical system that can obtain the illumination light having the uniform illuminance distribution. Further, according to the present invention, the relative position between the mask and the substrate can be detected with high accuracy by using the light that has passed through the projection optical system having a substantially uniform illuminance distribution and a short wavelength. A third object of the present invention is to provide an exposure apparatus that includes a position detection device that does not require so much precision in adjustment. Furthermore,
A fourth object of the present invention is to provide a method of manufacturing a microdevice manufactured by forming a fine pattern using the above exposure apparatus.

[0011]

In order to solve the above-mentioned problems, an illumination optical system according to a first aspect of the present invention is an illumination optical system in which light emitted from a light source (1) is irradiated to an object (14, R, W).
In the illumination optical system (5, 7, 21 to 32) for irradiating the light source, the wavelength of the light emitted from the light source (1) is 200 n.
m or less, the light source (1) and the illuminated object (1
4, R, W) to diffuse the light emitted from the light source (1) in the optical path between the diffusion means (22, 62) and the diffusion means (22, 62). The diffusing means (22, 62) is arranged in the optical path between the means (22, 62) and the illuminated object (14, R, W).
At least one rod-shaped internal reflection type optical member (24, 2) that guides the diffused light diffused by the internal reflection.
6, 64, 66, 80). According to this invention, the wavelength emitted from the light source is 20
After the light of 0 nm or less is diffused by the rotating diffusing means, the diffused light is guided while being internally reflected by the rod-shaped internal reflection type optical member. Here, since the diffusing means is rotated, it is possible to reduce speckles on the irradiated surface even if the light from the light source is narrowed.
In addition, since the diffused light is diffused by the diffusing means and then is made incident on the rod-shaped internal reflection type optical member, it is reflected and guided at various angles inside the rod-shaped internal reflection type optical member. As a result, illumination light having a uniform illuminance distribution can be obtained. In addition, since a rod-type internal reflection type optical member is used to guide the light from the light source, there is a high degree of freedom in how to guide the laser light in accordance with the device configuration, and strict optical adjustment accuracy is required. Since the adjustment is not performed, the adjustment is easy, and as a result, the cost required for the adjustment and the cost of the illumination optical system can be reduced. In the illumination optical system according to the first aspect of the present invention, the rod-shaped internal reflection optical member (24, 26, 64, 66, 80) has a circular cross section or a rectangular cross section. It is preferable. Further, in the illumination optical system according to the first aspect of the present invention, the diffusing means (22, 62) corresponds to the cross-sectional shape of the rod-shaped internal reflection type optical member (24, 26, 64, 66, 80). It is preferable to include a diffractive optical element that forms a predetermined illuminance distribution. Furthermore, in the illumination optical system according to the first aspect of the present invention, the incident surface of the rod-shaped internal reflection type optical member (24, 26, 64, 66, 80) is
It is preferable that the diffusing means (22, 62) are arranged at a predetermined angle with respect to the light incident thereon. here,
In the illumination optical system according to the first aspect of the present invention, the diffusing means (22, 62) is provided rotatably about a direction substantially parallel to a traveling direction of light emitted from the light source (1). Preferably. The illumination optical system according to the first aspect of the present invention includes: a lens system (25, 65) in which a front focal position is arranged on an exit surface of the rod-shaped internal reflection type optical member (24, 64); Lens system (25, 65)
It further comprises a second rod-shaped internal reflection type optical member (26, 66) having an incident surface arranged at the rear focal position. According to the present invention, since the light flux emitted from the exit end of the rod-shaped internal reflection type optical member and passing through the lens system illuminates the incident surface of the second rod-shaped internal reflection type optical member by Koehler illumination, it is uniform. It is extremely suitable for obtaining illumination light with a wide illuminance distribution. Further, the illumination optical system according to the first aspect of the present invention is configured such that the rod-shaped internal reflection type optical member (24, 64) and the second rod-shaped internal reflection type optical member (26, 66) are relative to each other. It is preferable to further include a correction member (40 to 43) that corrects the positional displacement. In order to solve the above-mentioned problems, an illumination optical system according to a second aspect of the present invention is an illumination optical system (5, which irradiates an object to be illuminated (14, R, W) with light emitted from a light source (1).
7, 21-32), the wavelength of the light emitted from the light source (1) is 200 nm or less, and the light source (1)
And a diffusing means (22, 62) arranged in an optical path between the illuminated object (14, R, W) and diffusing light emitted from the light source (1), and the diffusing means ( 22,
62) arranged in the optical path between the irradiation target object (14, R, W) and guiding the diffused light diffused by the diffusing means (22, 62) to the exit surface while internally reflecting the diffused light. Rod-shaped internal reflection type optical member (24, 64), and an optical path between the first rod-shaped internal reflection type optical member (24, 64) and the irradiated object (14, R, W). A second rod-shaped internal reflection type optical member (26, 66) disposed inside and guiding the incident light to the emission surface while reflecting the internal surface, and the first rod-shaped internal reflection type optical member (24, 64) and the second rod-shaped inner surface reflection type optical member (26, 6).
6) lens system (25, 6) disposed in the optical path between
5) and the front focus position of the lens system (25, 65) is the first rod-shaped internal reflection type optical member (2).
4, 64) on the exit surface, and the rear focal position of the lens system (25, 65) is positioned on the entrance surface of the second rod-shaped internal reflection type optical member (26, 66). It is characterized by that. In order to solve the above problems, an exposure apparatus according to a first aspect of the present invention is an exposure apparatus which transfers a pattern (DP) formed on a mask (R) onto a substrate (W), wherein the substrate (W) And a substrate stage (13) for holding the illumination light (IL) on at least a partial region of the mask (R) as the irradiated object.
The illumination optical system (5, 21 to 32) for irradiating 1) is provided. In order to solve the above problems, an exposure apparatus according to a second aspect of the present invention transfers a pattern (DP) formed on a mask (R) onto a substrate (W) via a projection optical system (PL). A substrate stage (13) for holding the substrate (W) in an exposure apparatus
An illumination optical system (5, 21 to 32) for illuminating a reference member (14) provided on the substrate stage (13) as the illuminated object with illumination light (IL1), and the projection optical system. A position measuring device (20, 90) for measuring the position of the substrate stage (13) by observing the reference member (14) via (PL). In order to solve the above problems, the first aspect of the present invention
In the method for manufacturing a micro device according to the above aspect, a stage position measuring step (S12) of measuring the position of the substrate stage (13) using the position measuring device (20, 90) provided in the exposure apparatus, and the stage position Measuring process (S
12) based on the measurement result of the substrate stage (1
3) adjusting step (S26) of adjusting the relative position between the mask (R) and illuminating the mask (R) with illumination light to project the pattern (DP) formed on the mask (R). A transfer step (S28) of transferring to the substrate (W) via an optical system (PL), and a developing step (S36) of developing the substrate (W) transferred in the transfer step (S28).
It is characterized by having and. In order to solve the above-mentioned problems, an exposure apparatus according to a third aspect of the present invention provides a projection optical system (P) with a pattern (DP) formed on a mask (R).
In an exposure apparatus that transfers to a substrate (W) via L),
A light source (1) that emits light having a wavelength of 200 nm or less; a substrate stage (13) that holds the substrate (W) and has a reference member (14) that defines a reference position; and the light source (1). At least one rod-shaped internal reflection type optical member (24, 26) which is arranged in the optical path between the reference member (14) and internally reflects the light from the light source (1) to guide it to the emission side. And a position measuring device (20, 90) for detecting the reference member (14) based on light that has passed through the rod-shaped internal reflection type optical members (24, 26) and the projection optical system (PL). It is characterized by having. According to this invention, since the rod-type internal reflection type optical member is used to guide the light from the light source to the position measuring device,
The degree of freedom in guiding the laser light is high according to the device configuration,
Moreover, since strict optical adjustment accuracy is not required, the adjustment is easy, and as a result, the cost required for the adjustment and the cost of the exposure apparatus can be reduced. In addition, the relative position between the mask and the substrate can be detected with high accuracy by using the light that has passed through the projection optical system and has a substantially uniform illuminance distribution and a short wavelength. Further, the exposure apparatus according to the third aspect of the present invention is characterized in that the rod-shaped inner surface reflection type optical member (24, 26) has a circular cross section or a rectangular cross section. Further, in the exposure apparatus according to the third aspect of the present invention, the light emitted from the light source (1) is in the optical path between the light source (1) and the rod-shaped internal reflection type optical member (24, 26). It is preferable to further comprise a diffusing means (22) for diffusing. Furthermore, in the exposure apparatus according to the third aspect of the present invention, the incident surface of the rod-shaped internal reflection type optical member (24, 26) is
It is preferably arranged at a predetermined angle with respect to the light incident on the diffusing means (22). In the exposure apparatus according to the third aspect of the present invention, the diffusing means (22) is
It is characterized in that it is rotatable about a direction parallel to the traveling direction of the light emitted from the light source (1). Here, in the exposure apparatus according to the third aspect of the present invention, the diffusing means (22) is rotatably provided about a direction substantially parallel to the traveling direction of the light emitted from the light source (1). Preferably. The exposure apparatus according to the third aspect of the present invention is a lens system (25) in which a front focal position is arranged on the exit surface of the rod-shaped internal reflection type optical member (24), and the lens system (25). And a second rod-shaped internal reflection type optical member (26) having an incident surface arranged at the rear focal position. Further, in the exposure apparatus according to the third aspect of the present invention, the relative positional deviation between the rod-shaped inner surface reflection type optical member (24) and the second rod-shaped inner surface reflection type optical member (26). It is preferable to further include a correcting member (40 to 43) for correcting. Furthermore, in the exposure apparatus according to the third aspect of the present invention, the position measuring apparatus (20) is configured so that the mask (R) is based on the light that has passed through the rod-shaped internal reflection type optical member (24, 26). It is characterized in that the upper mark (RM) is detected to measure the relative positional relationship between the substrate stage (13) and the mask (R). In order to solve the above-mentioned problems, a method for manufacturing a microdevice according to a second aspect of the present invention uses the position measuring device (20) provided in an exposure apparatus according to the third aspect of the present invention to use the substrate stage (13). Position measuring step (S12) for measuring the relative positional relationship between the mask (R) and the mask (R), and the position measuring step (S1).
Based on the measurement result of 2), the substrate stage (13)
Adjustment step (S26) of adjusting the relative position between the mask (R) and the mask (R), and a pattern (DP) formed on the mask (R) by irradiating the mask (R) with illumination light (IL).
Of the image of the substrate (W) through the projection optical system (PL)
And a developing step (S36) of developing the substrate (W) on which the pattern (DP) image has been transferred in the transferring step. The light source (1) used in the present invention is 180
It is preferable to supply light having a wavelength of nm or less, and it is more preferable that the light source (1) is an F ₂ laser.

[0012]

DETAILED DESCRIPTION OF THE INVENTION An illumination optical system, an exposure apparatus, and a microdevice manufacturing method according to embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, when an XYZ rectangular coordinate system is shown in the drawings, the positional relationship of each member between the drawings will be described with reference to the XYZ rectangular coordinate system. The XYZ orthogonal coordinate system shown in the drawing is set such that the X axis and the Y axis are parallel to the wafer W as a substrate, and the Z axis is set in a direction orthogonal to the wafer W. In the XYZ coordinate system in the figure, the XY plane is actually set to a plane parallel to the horizontal plane, and the Z axis is set to the vertically upward direction. Also,
The exposure apparatus described below includes a reticle R as a mask and a wafer W as a photosensitive substrate for the projection optical system PL.
A step-and-scan type exposure apparatus that transfers the pattern formed on the reticle R onto the wafer W while relatively moving and will be described as an example. In each of the following embodiments, the direction (scanning direction) in which the reticle R and the wafer W are moved is set to the X direction.

FIG. 1 is a diagram showing a schematic configuration of an entire exposure apparatus according to an embodiment of the present invention. In FIG. 1, 1
Is a light source that emits laser light having a wavelength of 200 nm or less, such as an ArF excimer laser (193 nm) or an F ₂ laser (157 nm). The laser light emitted from the light source 1 passes through the relay lens 2, is reflected by the reflection mirror 3, and is deflected in the Z direction. Then, the light enters the half mirror 5 via the relay lens 4. The laser light transmitted through the half mirror 5 is reflected by the reflection mirror 6 and then deflected in the X direction to enter the illumination optical system 7. This illumination optical system 7
Shape the cross-sectional shape of the incident laser light,
Illumination distribution I is made uniform by adjusting the illuminance
It is emitted as L. Details of the internal configuration of the illumination optical system 7 will be described later. Instead of the half mirror 5, a switching mirror that can be inserted into and removed from the optical path may be applied.

When the illumination light IL is emitted from the illumination optical system 7, the illumination light IL on the reticle R is illuminated with a substantially uniform illuminance. When the reticle R is illuminated with the illumination light IL, the pattern D formed on the reticle R
The image of P is projected onto the wafer W via the projection optical system PL, and the pattern is transferred. Here, the reticle R is
It is mounted on a reticle stage 9 as a mask stage that can be finely moved in the direction of the optical axis AX of the projection optical system PL by a motor 8 and can be two-dimensionally moved and finely rotated in a plane perpendicular to the optical axis AX. There is. A movable mirror 11 that reflects the laser beam from the laser interferometer 10 is fixed to an end of the reticle stage 9, and the movable mirror 11 is fixed to the reticle stage 9.
The dimensional position is determined by the laser interferometer 10, for example, 0.
It is constantly detected with a resolution of about 01 μm.

The projection optical system PL is, for example, telecentric on both sides (may be on one side), and has the best aberration correction with respect to the wavelengths of the illumination light IL and the alignment light. It has an optically conjugate relationship. The illumination light IL is Keller illumination and is formed as a light source image at the center of the pupil (not shown) of the projection optical system PL. The projection optical system PL has optical elements such as a plurality of lenses, and the glass material of the optical elements is fluorite (calcium fluoride: CaF ₂ ) or magnesium fluoride (MgF ₂ ) depending on the wavelength of the illumination light IL. ), Lithium fluoride (LiF), barium fluoride (BaF ₂ ),
Strontium fluoride (SrF ₂ ), LiCAF (corkyrite: LiCaAlF ₆ ), LiSAF (LiSr
AlF ₆ ), LiMgAlF ₆ , LiBeAlF ₆ , KM
It is selected from fluoride crystals such as gF ₃ , KCaF ₃ and KSrF ₃ or mixed crystals thereof, and optical materials such as quartz glass doped with substances such as fluorine and hydrogen, which transmit vacuum ultraviolet light. It should be noted that the quartz glass doped with a predetermined substance is used as the illumination light I.
Since the transmittance decreases when the wavelength of L is shorter than about 150 nm, when vacuum ultraviolet light having a wavelength of about 150 nm or less is used as the illumination light IL, the optical material of the optical element is fluorite (calcium fluoride). , Magnesium fluoride, lithium fluoride, barium fluoride, strontium fluoride, LiCAF (corkyrite), LiSAF (L
iSrAlF ₆ ), LiMgAlF ₆ , LiBeAl
Fluoride crystals such as F ₆ , KMgF ₃ , KCaF ₃ , KSrF ₃ or mixed crystals thereof are used.

The wafer W is placed on a wafer stage 13 as a substrate stage via a wafer holder 12. On the wafer stage 13, there is provided a reference member 14 having a reference mark used for baseline measurement and for measuring a lateral shift amount of a mark with respect to a shift amount of a focus position of an alignment sensor described later. This reference member 14
Position of the wafer W in the Z-axis direction is
It is set at almost the same position as the surface position of. As the reference mark, for example, a slit pattern composed of five light-transmitting L-shaped patterns and two sets of reference patterns (duty ratio 1: 1) formed of light-reflective chrome are provided. There is.

The wafer stage 13 is an XY stage for two-dimensionally positioning the wafer W in a plane perpendicular to the optical axis AX of the projection optical system PL, and a direction (Z direction) parallel to the optical axis AX of the projection optical system PL. Z stage for positioning the wafer W on the
The stage includes a stage for slightly rotating the wafer W, a stage for changing the angle with respect to the Z-axis to adjust the inclination of the wafer W with respect to the XY plane, and the like. An L-shaped moving mirror 15 is attached to one end of the upper surface of the wafer stage 13, and the laser interferometer 1 is provided at a position facing the mirror surface of the moving mirror 15.
6 are arranged. Although simplified in FIG. 1, the movable mirror 15 is composed of a plane mirror having a reflecting surface perpendicular to the X axis and a plane mirror having a reflecting surface perpendicular to the Y axis. In addition, the laser interferometer 16 includes the movable mirror 1 along the X axis.
5 is composed of two X-axis laser interferometers for irradiating a laser beam, and a Y-axis laser interferometer for irradiating the moving mirror 15 with a laser beam along the Y-axis. With a laser interferometer and one laser interferometer for the Y axis,
The X coordinate and Y coordinate of the wafer stage 13 are measured.
Further, the rotation angle of the wafer stage 13 in the XY plane is measured by the difference between the measurement values of the two laser interferometers for the X axis.

The two-dimensional coordinates of the wafer stage 13 are
The laser interferometer 16 is constantly detected with a resolution of, for example, about 0.01 μm, and the stage coordinate system (stationary coordinate system) (X, Y) of the wafer stage 13 is determined by the coordinates in the X-axis direction and the Y-axis direction. That is, the laser interferometer 1
The coordinate values of the wafer stage 13 measured by 6 are coordinate values on the stage coordinate system (X, Y). A position measurement signal indicating the X coordinate, the Y coordinate, and the rotation angle measured by the laser interferometer 16 is output to the main control system 18. The main control system 18 sends a control signal for controlling the position of the wafer stage 13 to the motor 17 while monitoring the supplied position measurement signal.
Output to.

When the main control system 18 transfers the pattern DP formed on the reticle R onto the wafer W, the signal output from the laser interferometer 10 and the laser interferometer 16 are transferred.
The reticle stage 9 and the wafer stage 13 are synchronously moved along the X direction via the motor 8 and the motor 17 based on the position measurement signal output from. Further, the exposure apparatus of this embodiment includes an off-axis alignment system 19 on the side of the projection optical system PL, and the wafer alignment mark WM and the reference member formed on the wafer W by the off-axis alignment system 19 as well. 14
It is configured to be able to measure the position information of the reference mark formed on the.

On the other hand, the laser light reflected by the half mirror 5 simultaneously observes the reference mark and the reticle mark formed on the reticle via the projection optical system, and measures the relative positional relationship between the two. The reticle) sensor 20 guides the reticle. The TTR sensor 20 has a reticle alignment mark RM formed on the reticle R.
And the wafer alignment mark WM formed on the wafer W or the reference mark formed on the reference member 14 through the projection optical system PL to detect their relative positions. It corresponds to the so-called position measuring device. The TTR sensor 20 includes a field diaphragm plate 28, a relay lens 29, a beam splitter 30, and a first objective lens 3.
1, a bending mirror 32, a reflecting mirror 33, a second objective lens 34, and an image pickup device 35 such as a CCD (Charge Coupled Device).

Further, the relay lens 21, the diffusion plate 22, the driving device 23, the first rod lens 24, the condenser lens 25, the second rod lens 26, and the relay lens 27.
Constitute a relay optical system for guiding a part of the laser light emitted from the light source 1 to the TTR sensor 20. The laser light reflected by the half mirror 5 is guided to the diffusion plate 22 via the relay lens 21. The diffusing plate 22 corresponds to the diffusing means according to the present invention, and diffuses the laser light incident through the relay lens 21 to convert the light intensity distribution. The reason for providing the diffusion plate 22 is the light emitted from the TTR sensor 20 (hereinafter referred to as alignment light).
This is to make the illuminance distribution uniform and improve the detection accuracy. The details will be described later. Also, the drive device 23 in the figure
Is the optical axis AX1 of the relay lens 21 (this optical axis AX1
Is for rotating the diffuser plate 22 about an axis parallel to the traveling direction of the laser light reflected by the half mirror 5). Here, the reason why the diffusing plate 22 is configured to be rotatable around an axis parallel to the optical axis AX1 is to improve detection accuracy by reducing speckles.

The laser light diffused by the diffusion plate 22 is
The light enters the first rod lens 24 from the incident end of the rod lens 24. The first rod lens 24 internally guides the laser light reflected by the half mirror 5 and guides it to the exit end, and corresponds to the rod-shaped internal reflection type optical member in the present invention. The reason for providing the first rod lens 24 is to reduce the cost by simplifying the configuration of the optical system that guides the light reflected by the half mirror 5 to the TTR sensor 20 and facilitating the optical adjustment. ,
This is also for improving the detection accuracy of the TTR sensor 20.

The conventional exposure apparatus is equipped with a light source such as a mercury lamp which emits light having a wavelength longer than 200 nm. The light in this wavelength range uses an optical fiber made of a quartz material. And could easily lead to the TTR sensor. However, when the wavelength of the laser light emitted from the light source becomes 200 nm or less, the absorption becomes large in the conventionally used optical fiber, so that it is difficult to use it for the purpose of guiding a part of the light emitted from the light source to the TTR sensor. Is becoming. Therefore, part of the laser light from the light source is TT
If a relay optical system composed of a relay lens or the like is used for guiding to the R sensor, high precision optical adjustment is required, resulting in an increase in cost and an optical characteristic of the relay optical system due to external vibration or the like. Fluctuates and deteriorates the detection accuracy of the TTR sensor.
Therefore, in the present embodiment, some of the above problems are solved by guiding the laser light using the first rod lens 24.

As a glass material forming the first rod lens 24, fluorite (calcium fluoride: CaF) depending on the wavelength of the laser beam emitted from the light source 1 is used as in the optical element constituting the projection optical system PL. ₂ ), magnesium fluoride (MgF ₂ ), lithium fluoride (LiF), barium fluoride (BaF ₂ ), strontium fluoride (SrF ₂ ),
LiCAF (corkylite: LiCaAlF ₆ ), Li
SAF (LiSrAlF ₆ ), LiMgAlF ₆ , LiB
It is selected from a fluoride crystal such as eAlF ₆ , KMgF ₃ , KCaF ₃ , KSrF ₃ or a mixed crystal thereof, or an optical material that transmits vacuum ultraviolet light such as quartz glass doped with a substance such as fluorine or hydrogen. Since quartz glass doped with a predetermined substance has a reduced transmittance when the wavelength of laser light is shorter than about 150 nm, when vacuum ultraviolet light having a wavelength of about 150 nm or less is used as the illumination light IL, an optical element is used. Examples of the optical material include fluorite (calcium fluoride), magnesium fluoride, lithium fluoride, barium fluoride, strontium fluoride, LiCAF (corkyrite), Li
SAF (LiSrAlF ₆ ), LiMgAlF ₆ , LiB
Fluoride crystals of eAlF ₆ , KMgF ₃ , KCaF ₃ , KSrF ₃ or mixed crystals thereof are used. The length of the first rod lens 24 is appropriately set in consideration of both the transmittance of the laser light incident from the incident end and the distance that the incident laser light has to be guided to the TTR sensor 20.

2 and 3 are perspective views showing an example of the first rod lens 24. As shown in FIG. The cross-sectional shape of the first rod lens 24 is formed into a circular shape shown in FIG. 2 (a), a rectangular shape shown in FIG. 2 (b), or a triangular shape shown in FIG. 2 (c). Are formed to be substantially the same along the longitudinal direction. That is, the first rod lens 24 shown in FIG. 2A is a cylindrical rod lens, and the first rod lens 24 shown in FIG. 2B is a quadrangular rod lens. First shown in c)
The rod lens 24 is a triangular prism-shaped rod lens.

Since the rod lenses 24a shown in FIGS. 2A to 2C all have a higher refractive index than air, the laser light incident from the incident end is propagated to the exit end while being totally reflected on the side surface. As described above, the first rod lens 24 propagates the laser light that is incident while being totally reflected on the inner surface, and thus the first rod lens 24 is not limited to the configuration shown in FIGS.
The structures shown in (a) to (c) can also be used. The first rod lens 24 shown in FIGS.
Each of the cross-sectional shapes is a cylindrical shape, a quadrangular prism shape, and a triangular prism shape, like the cross-sectional shape of the rod lens shown in FIGS. 2A to 2C, but the surroundings have a lower refractive index and a lower refractive index. It is different in that it is configured to be covered with a member having a ratio. The first rod lens 24 having such a configuration is also shown in FIGS.
Similar to the rod lens shown in (c), it has a function of propagating an incident laser beam while being totally reflected by the inner surface (a boundary surface between a portion formed of fluorite and the like and a portion covering the portion).

Further, as shown in FIG. 4, the incident surface of the first rod lens 24 is arranged at a predetermined angle θ with respect to the laser light incident on the diffusion plate 22. In other words,
Optical axis AX1 of relay lens 21 and first rod lens 24
Is arranged so as to form an angle θ with the optical axis AX2. Figure 4
FIG. 6 is a diagram showing an arrangement relationship between the diffusion plate 22 and the first rod lens 24. Here, the angle θ is set so as to satisfy 4 ° ≦ θ ≦ 10 °. Here, the reason why a predetermined angle is formed between the incident surface of the first rod lens 24 and the laser light incident on the diffusion plate 22 is as follows. That is, even if the diffusion plate 22 is arranged on the incident side of the first rod lens 24 and the incident end of the first rod lens 24 is illuminated with almost complete diffused light, the angular distribution of the luminance of the light flux from the exit end is It tends to decrease as the emission angle increases.

FIG. 5 is a diagram showing an example of a state of a light beam emitted from the emission surface when laser light is incident on the incident surface of the first rod lens 24 from an oblique direction. The case where the cross-sectional shape of the first rod lens 24 is circular is illustrated. As shown in FIG. 5, when linear laser light enters at an angle θ with respect to the optical axis AX2 of the first rod lens 24, a light beam having a conical shape diverging from the exit end of the first rod lens 24. Is ejected. As described above, the first rod lens 24 is configured to reduce the incident angle of the light beam and the first angle.
It has a characteristic that a light flux having a cross-sectional shape that reflects the cross-sectional shape of the rod lens 24 is emitted from the emission end.

Therefore, by utilizing the characteristics of the first rod lens 24, the laser beam is incident on the incident surface of the first rod lens 24 from an oblique direction, and the laser beam is made large from the exit end of the first rod lens 24. The difference between the brightness of the light beam emitted at an angle and the brightness of the light beam emitted at a small angle can be reduced. That is, the first rod lens 2
By illuminating the incident surface of 4 from an oblique direction,
The angular distribution of the brightness of the light flux from the exit end of the first rod lens 24 can be relaxed. For the reason described above, a predetermined angle is set between the incident surface of the first rod lens 24 and the laser light incident on the diffusion plate 22.

Further, the predetermined angle θ is within the above range (4 °
The reason for setting ≦ θ ≦ 10 ° is as follows. That is, when the angle θ is less than 4 °, the above-described characteristic of the first rod lens 24 itself (the characteristic in which the brightness decreases as the emission angle at the emission end increases) cannot be canceled out, and conversely. When the angle θ is larger than 10 °, the characteristics of the first rod lens 24 itself are canceled out too much, and the brightness increases as the emission angle at the emission end increases. . Incidentally, FIG.
In consideration of the characteristics of the first rod lens 24 shown in FIG. 6, the diffusion characteristics of the diffusion plate 22 are set to the characteristics shown in FIG.
FIG. 6 is a diagram showing an example of diffusion characteristics along the Y-axis direction of a diffusion plate 22 having a circular cross-sectional shape. In FIG. 6, reference numeral C1
The position marked with indicates the position on the optical axis AX1. As shown in FIG. 6, the diffusion plate 22 has a higher brightness on the optical axis C1,
The diffusion characteristic is set so that the brightness gradually decreases as it deviates from the optical axis C1.

If the cross-sectional shape of the first rod lens 24 is the circular shape shown in FIG. 2A or 3A, the angle θ is set within the above range (4 ° ≦ θ ≦ 10 °). It is not necessary to consider which surface includes the optical axis AX1 and the optical axis AX2, but the first rod lens 24
2B or 3B has a rectangular shape or a triangular shape shown in FIG. 2C or 3C, not only the angle θ but also the optical axis AX1 and the optical axis Axis AX2
The half mirror 5, the relay lens 21, the diffusion plate 22, and the first rod lens 23 must be arranged in consideration of the surface including and. If this arrangement is not considered, the first
This is because the luminous intensity distribution of the luminous flux emitted from the rod lens 23 occurs.

First rod lens 2 having a circular cross section
In order to obtain the same effect as that of 4, the half mirror 5, the relay lens 21, the diffusion plate 22, and the first rod lens 23
The following arrangement is desirable. When the cross-sectional shape is a rectangular shape, it is desirable that the surface including the optical axis AX1 and the optical axis AX2 further includes a diagonal line of the cross section of the first rod lens 23. When the cross-sectional shape is a triangular shape, the plane including the optical axis AX1 and the optical axis AX2 is
It is desirable to arrange the first rod lens 23 so as to be parallel to one side of the cross section of the first rod lens 23.

Next, the condenser lens 25 corresponds to the lens system according to the present invention, and the second rod lens 26 corresponds to the second rod-shaped internal reflection type optical member according to the present invention. The front focus position of the condenser lens 25 is the first
The second rod lens 26 is positioned so as to be positioned on the exit surface of the rod lens 24, and the second rod lens 26 is positioned so that the entrance surface is positioned at the rear focal position of the condenser lens 25, and the entrance end and the exit end of the second rod lens 26 are positioned. The ends are arranged so as to be substantially perpendicular to the optical axis AX2. As shown in FIG. 7, the condenser lens 25 arranged in this way
The laser light emitted from the rod lens 24 acts so as to Koehler-illuminate the incident surface of the second rod lens 26. FIG. 7 is a diagram showing a state in which the incident surface of the second rod lens 26 is Koehler-illuminated. As shown in FIG.
Each of the homologous luminous fluxes emitted from two different emission ends of the first rod lens 14 passes through the condenser lens 25 and illuminates the entire incident surface of the rod lens 26.

The reason why the incident surface of the second rod lens 26 is Koehler-illuminated by using the condenser lens 25 is to uniformize the illuminance distribution in the plane perpendicular to the optical axis AX2. That is, the laser emitted from the light source 1 does not have a uniform illuminance distribution but a certain distribution, and the distribution fluctuates with time. There is a possibility that a detection error may occur when irradiating the reticle alignment mark RM and the wafer alignment mark WM or the reference mark with the laser light having such a temporally varying distribution as the alignment light IL1 to detect these positions, and thus high accuracy is achieved. This is a problem in detecting the position. Therefore, with the configuration shown in FIG. 7, the illuminance distribution in the plane perpendicular to the optical axis AX2 is made as uniform as possible.

The second rod lens 26 internally reflects the laser light emitted from the first rod lens 24 and transmitted through the condenser lens 25, and guides it to the emission end. The reason why the second rod lens 26 is provided is the same as the reason why the first rod lens 24 is provided, which simplifies the configuration of the optical system that guides the laser light to the TTR sensor 20 and facilitates the optical adjustment. By doing so, the cost can be reduced and the detection accuracy of the TTR sensor 20 can be improved. As the glass material forming the second rod lens 26, as in the case of the first rod lens 24, the light source 1
Fluorite (calcium fluoride: CaF ₂ ) and magnesium fluoride (Mg) according to the wavelength of the laser beam emitted from
F ₂ ), lithium fluoride (LiF), barium fluoride (BaF ₂ ), strontium fluoride (SrF ₂ ), Li
CAF (corkylite: LiCaAlF ₆ ), LiSA
F (LiSrAlF ₆ ), LiMgAlF ₆ , LiBeA
_{lF 6, KMgF 3, KCaF 3} , KSrF 3 fluoride crystal or mixed crystal thereof, such as, also be selected from an optical material which transmits vacuum ultraviolet light quartz glass or the like material doped with such fluorine or hydrogen.

Quartz glass doped with a predetermined substance is
Since the transmittance decreases when the wavelength of the laser light is shorter than about 150 nm, when vacuum ultraviolet light having a wavelength of about 150 nm or less is used as the illumination light IL, the optical material of the optical element is fluorite (calcium fluoride). ), Magnesium fluoride, lithium fluoride, barium fluoride, strontium fluoride, LiCAF (corkyrite), LiSA
F (LiSrAlF ₆ ), LiMgAlF ₆ , LiBeA
_{lF 6, KMgF 3, KCaF 3} , KSrF 3 fluoride crystal or mixed crystal thereof, such as are used. If necessary, the optical member forming the condenser lens 25 may also be formed of the same glass material as the first rod lens 24 and the second rod lens 26. Further, the second rod lens 26
Is similar to the first rod lens 24, its cross-sectional shape is circular as shown in FIG. 2A, rectangular as shown in FIG.
Alternatively, the triangular shape shown in FIG. 2C, or the triangular shape shown in FIG.
9 to (c). Further, the length of the second rod lens 26, like the first rod lens 24, considers both the absorptance of the laser light incident from the incident end and the distance at which the incident laser light must be guided to the TTR sensor 20. And set appropriately.

Here, it is conceivable that the relative displacement between the first rod lens 24 and the second rod lens 26 may occur due to external vibration or the like. Therefore, it is preferable to provide a correction member that corrects the relative positional deviation between the first rod lens 24 and the second rod lens 26. Figure 8
FIG. 4 is a diagram showing a configuration example of a correction member that corrects a relative positional deviation between the first rod lens 24 and the second rod lens 26. In FIG. 8A, the second rod lens 26
Is set to the Z-axis direction in the drawing, and the bending mirror 4 that reflects the light beam emitted from the exit end of the first rod lens 24 and guides it to the entrance end of the second rod lens 26.
0 is provided. The folding mirror 40 corresponds to the correction member according to the present invention.

Bending mirror 40 shown in FIG.
Is configured to be rotatable around a rotation axis set parallel to the Y axis, for example, and the first rod lens 24 is displaced in the Z direction or the second rod lens 26 is displaced in the X direction. In this case, the relative displacement of the first rod lens 24 and the second rod lens 26 can be corrected by adjusting the rotation angle of the folding mirror 40 about the rotation axis. When the first rod lens 24 or the second rod lens 26 is displaced in the Y direction, the bending mirror 4
The rotation angle around the rotation axis that is parallel to the reflection surface of 0 and parallel to the paper surface may be adjusted. As described above, if the bending mirror 40 is adjusted according to the relative displacement amount of the first rod lens 24 and the second rod lens 24, the relative positional deviation between the first rod lens 24 and the second rod lens 26. Can be corrected.

In the example shown in FIG. 8B, the bending mirror 41 arranged on the optical path between the first rod lens 24 and the condenser lens 25, and the condenser lens 2
5 and the bending mirrors 42 and 43 arranged on the optical path between the second rod lens 26. These folding mirrors 41 to 43 correspond to the correction member according to the present invention. In the example shown in FIG. 8B, the longitudinal directions of the first rod lens 24 and the second rod lens 26 are both set in the X direction, and the second rod lens 24 is set as in the configuration example shown in FIG. 8A. Since it is not necessary to change the longitudinal direction of the lens 26, the degree of freedom in the device configuration of the exposure device is increased.

The bending mirror 41 is the first rod lens 4
It is provided in order to reflect the light flux emitted from the exit end of No. 1 and guide it to the condenser lens 25, and to correct the displacement amount of the first rod lens 24. Folding mirror 42
Are provided to reflect the light flux transmitted through the condenser lens 25 and guide it toward the incident end of the second rod lens 26. The folding mirror 43 is the folding mirror 42.
It is provided to make the light flux reflected by the light incident on the incident end of the second rod lens 26 and to correct the displacement amount of the second rod lens 26.

The folding mirrors 41 and 43 are configured to be rotatable about a rotation axis set parallel to the Y axis, for example, and the folding mirror 42 is configured to be translatable in the Z axis direction. In the configuration example shown in FIG. 8B, the displacement amount of the first rod lens 24 or the displacement amount of the second rod lens 2 is set to the angle around the rotation axis of the folding mirror 41 or the rotation axis of the folding mirror 43. It is possible to independently correct by adjusting each angle. Further, by translating the bending mirror 42 in the Z direction,
The exit end of the first rod lens 24 and the second rod lens 24
The change in the optical path length between and can be corrected.

Returning to FIG. 1, divergent light having a predetermined numerical aperture (NA) is emitted from the emission end of the second rod lens 26. The light flux emitted from the emission end of the second rod lens 26 passes through the relay lens 27, and then the reticle R
Of the field DP which is arranged at a position optically conjugate with the surface (reticle surface) on which the pattern DP and the reticle alignment mark RM are formed and which defines the irradiation area of the alignment light IL1 on the reticle R. The light enters the diaphragm plate 28. The light beam incident on the field diaphragm plate 28 is shaped into the shape of the field diaphragm formed on the field diaphragm plate 28, and then the relay lens 29 and the beam splitter 3 are formed.
The reticle alignment mark RM formed on the reticle R as alignment light IL1 is made substantially uniform by being incident on the bending mirror 32 via 0 and the first objective lens 31 in this order and being deflected in the −Z direction by the bending mirror 32. Use Koehler illumination with illuminance.

Here, the relay optical system and the T described above
How the alignment light having a uniform illuminance distribution can be obtained by using the TR sensor 20 will be described.
FIG. 9 is a diagram for explaining how the laser light emitted from the light source 1 is converted into alignment light having a uniform illuminance distribution via the relay optical system and the TTR sensor. In FIG. 9, the same members as those shown in FIG. 1 are designated by the same reference numerals. Half mirror 5 in Figure 1
The laser light reflected by is incident on the diffuser plate 22 along the optical axis AX1 via the relay lens 21. When this laser light passes through the diffusion plate 22, it is diffused according to the diffusion characteristics of the diffusion plate 22, and then enters the incident end of the first rod lens 24. The illuminance distribution of the laser light at the incident end of the first rod lens 24 is shown by a graph denoted by reference numeral G1 in FIG. The horizontal axis of the graph G1 is the position in the Y direction in FIG. 1, and the vertical axis is the illuminance.

As can be seen from the graph G1, in the illuminance distribution of the laser light, the level of illuminance varies depending on the position, and the position of this level fluctuates with time. When the laser light having such an illuminance distribution is incident on the first rod lens 24, the laser light is propagated while being multiple-reflected inside the first rod lens 24, but the fluctuation of the illuminance distribution at the exit end is not canceled so much. This element is shown in graph G2. The light beam emitted from the exit end of the first rod lens 24 illuminates the entrance end of the second rod lens 26 via the condenser lens 25 as described above, and thus the second rod lens 26 as shown in the graph G3. The illuminance distribution of the light beam incident on the incident end of is almost uniform.

The light beam incident on the incident end of the second rod lens 26 has various angle components, and these components are propagated while being multiple-reflected inside the second rod lens 26. The non-uniformity is further eliminated in the light flux emitted from the exit end of 26, and as shown in the graph G4,
A more uniform illuminance distribution is obtained. The light flux having such a uniform illuminance distribution includes a relay lens 27, a field diaphragm plate (not shown in FIG. 9), a relay lens 29, a beam splitter (not shown in FIG. 9), a first objective lens 31,
Then, at least a part of the reticle surface RP is Koehler-illuminated through a bending mirror (not shown in FIG. 9) in order. A graph G5 in FIG. 9 is a graph showing the illuminance distribution of the alignment light that illuminates the reticle surface RP. From this graph G5, it can be seen that the reticle surface RP is illuminated with alignment light having a uniform illuminance distribution.

The relay lens 21, the relay lens 27, the relay lens 29, and the beam splitter 3 shown in FIG.
0 and the first objective lens 31, considering the transmittance,
Depending on the wavelength of the laser light emitted from the light source 1, fluorite (calcium fluoride: CaF ₂ ), magnesium fluoride (M
gF ₂ ), lithium fluoride (LiF), barium fluoride (BaF ₂ ), strontium fluoride (SrF ₂ ), Li
CAF (corkylite: LiCaAlF ₆ ), LiSA
F (LiSrAlF ₆ ), LiMgAlF ₆ , LiBeA
It is made of an optical material such as 1F ₆ , KMgF ₃ , KCaF ₃ , KSrF ₃ or the like, or a mixed crystal thereof, or a vacuum ultraviolet light transmitting material such as quartz glass doped with a substance such as fluorine or hydrogen. Is preferred. However, 200n
It may be formed of general quartz used as a material of a lens used in a wavelength range of m or more. However, when quartz is used, it is desirable to make the lens as thin as possible.

Although not shown in FIG. 1, two TTR sensors 20 are provided above the reticle R and along the X direction. Therefore, a relay optical system including the relay lens 21, the diffusion plate 22, the driving device 23, the first rod lens 24, the condenser lens 25, the second rod lens 26, and the relay lens 27 shown in FIG. 1 is further provided in parallel. Alternatively, an optical system for dividing the second rod lens 2 and guiding it to a TTR sensor (not shown) is provided.

The alignment light IL1 transmitted through the reticle alignment mark RM is transmitted through the projection optical system PL and the wafer alignment mark W formed on the wafer W.
The reference mark formed on M or the reference member 14 is illuminated. When illuminating the wafer alignment mark WM or the reference mark, the wafer alignment mark WM or the reference mark is arranged at a position where the alignment light is illuminated. Here, the reticle surface of the reticle R and the wafer W
Since it is arranged so as to be optically conjugate with the surface of the projection optical system PL, the alignment light that passes through the projection optical system PL is not aligned with the wafer alignment mark WM or the reference mark formed on the reference member 14. Koehler lighting. Alignment light is wafer alignment mark WM
Alternatively, the reflected light, the scattered light, and the diffracted light obtained by illuminating the reference mark follow the optical path of the alignment light in the reverse order to reach the reticle alignment mark RM, and are reflected, scattered, or diffracted by this light and the reticle alignment mark RM. The reflected light is combined, is incident on the bending mirror 32, and is deflected in the −X direction.

Then, it is reflected by the beam splitter 30 via the first objective lens 36. Beam splitter 30
The light reflected by is reflected by the reflection mirror 33, is deflected in the −X direction, is condensed by the second objective lens 34, and is incident on the image pickup surface of the image pickup device 35. Since the image pickup surface of the image pickup element 35 and the surface on which the reticle alignment mark RM and the wafer alignment mark WM or the reference mark of the reference member 14 are formed are optically conjugate with each other, the image pickup element An optical image of the reticle alignment mark RM and an optical image of the wafer alignment mark WM are formed on the imaging surface of 35. The image sensor 35 photoelectrically converts these optical images into an image signal and outputs the image signal to the main control system 1.
Output to 8. The main control system 18 performs image processing on the image signal output from the image sensor 35 to calculate relative positional deviation information between the reticle alignment mark RM and the wafer alignment mark WM or the reference mark (relative positional relationship). The reticle R and the wafer W are relatively aligned by individually moving the reticle stage 9 and the wafer stage 13 via the motor 8 and the motor 17 based on the calculated positional deviation information.

The overall structure of the exposure apparatus according to the embodiment of the present invention has been described above. Next, the structure of the illumination optical system 7 included in the exposure apparatus according to the embodiment of the present invention will be described. FIG. 10 is a diagram showing the configuration of the illumination optical system 7 provided in the exposure apparatus according to the embodiment of the present invention. Figure 10
The illumination optical system 7 shown in is an illumination optical system having a so-called double fly-eye lens system, and includes a beam shaping optical system 50,
First fly-eye lens 51, condenser lens system 52, second fly-eye lens 53, aperture stop plate 54, condenser lens 5
5, a reticle blind 56, a relay lens 57, a bending mirror 58, and a condenser optical system 59.

The beam shaping optical system 50 makes the cross-sectional shape of the laser light emitted from the light source 1 similar to the overall shape of the entrance end of the first fly-eye lens 51 which constitutes the entrance end of the double fly-eye lens system. As described above, the light beam is shaped so as to efficiently enter the first fly-eye lens 51. In the present embodiment, it is assumed that the zoom lens system includes a two-group zoom optical system including a cylindrical lens, a beam expander, and the like. The laser light transmitted through the beam shaping optical system 50 is incident on the first fly-eye lens 551 which constitutes a part of the double fly-eye lens system. This double fly-eye lens system is for uniformizing the intensity distribution of the illumination light, and a first fly-eye lens 51, a condenser lens system 52, and a second fly-eye lens 53 are arranged in order along the optical path. It was done. As the first fly-eye lens 51, although not shown here, a turret, that is, one in which the fly-eye lens is mounted on a rotatable disk is used. Therefore, by rotating the disk,
The fly-eye lens can be accurately positioned on the optical path of pulsed ultraviolet light.

The condenser lens system 52 condenses the light from the surface light source (a large number of point light sources) formed at the exit end of the first fly-eye lens 51 to the second fly-eye lens 53 in the subsequent stage without loss. A three-group zoom optical system of a mechanical correction type that uses a zoom cam mechanism that continuously changes the entire focal length while keeping the image forming position on the same plane is used. Although not shown, interference fringes and weak speckles generated on the irradiated surface (reticle surface or wafer surface) are smoothed between the condenser lens system 52 and the second fly-eye lens 53. It is preferable to arrange a vibrating mirror for this. The vibration (deflection angle) of the vibrating mirror is controlled by an illumination control device (not shown) under the control of the main control system 18 via a drive system (not shown). Note that a configuration in which a double fly-eye lens system similar to that of the embodiment and a vibrating mirror are combined is disclosed in, for example, Japanese Patent Laid-Open No.
-259533 (and corresponding US Pat. No. 5,307,207) and the like.

An aperture stop plate 54 made of a disc-shaped member is arranged near the exit surface of the second fly-eye lens 53. The aperture stop plate 54 has, for example, an aperture stop formed of a normal circular aperture, a small circular aperture, and an aperture stop for reducing a coherence factor σ value and a ring for annular illumination. A band-shaped aperture stop and a deformed aperture stop for arranging four apertures eccentrically for the modified light source method are arranged. The aperture stop plate 54 is rotationally driven by a motor (not shown) controlled by the illumination control device (not shown) described above, and any aperture stop is positioned on the exit surface of the second fly-eye lens 53. ing. That is, in the present embodiment, a switching device that positions any aperture stop on the aperture stop plate 54 on the exit surface of the optical integrator by a motor (not shown) is configured. still,
FIG. 10 illustrates a case where an aperture stop having a normal circular aperture is arranged.

The light that has passed through the aperture stop plate 54 is condensed by a condenser lens 55 and then enters a reticle blind 56 as a field stop. This reticle blind 5
6 includes a fixed reticle blind 56a and a movable reticle blind 56b. The fixed reticle blind 56a is arranged on a surface that is slightly defocused from a surface that is optically conjugate to the surface on which the pattern of the reticle R is formed (reticle surface), and defines the illumination area on the reticle R. An opening having a predetermined shape is formed.
The opening of this fixed reticle blind 56a is the reticle R at the time of scanning exposure at the center of the circular visual field of the projection optical system PL.
It is assumed that it is formed in a slit shape or a rectangular shape linearly extending in the Y-axis direction orthogonal to the moving direction (X-axis direction).

It should be noted that the reason for slightly defocusing the arrangement surface of the fixed reticle blind 56a from the surface which is optically conjugate with the pattern surface of the reticle R is mainly the scanning type exposure apparatus, particularly the pulsed light exposure illumination. In an apparatus that uses light, the illuminance distribution in the illumination area on the reticle (wafer) of the pulsed light in the scanning direction is trapezoidal (that is, a shape having slopes at both ends), and each shot area on the wafer during scanning exposure This is to make the distribution of the integrated exposure amount in the inside substantially uniform.

The movable reticle blind 56b has, for example, two L-shaped movable blades and an actuator for driving the movable blades. The positions of the two movable blades are variable in the direction corresponding to the scanning direction of the reticle R and the direction corresponding to the non-scanning direction orthogonal to the scanning direction. The movable reticle blind 56b is fixed by the movable blade at the start and end of scanning exposure to prevent exposure of unnecessary portions.
It is used to further limit the illuminated area on the reticle R defined by 6a. The movable reticle blind 56b is controlled by the main control system 18. The light that has passed through the reticle blind 56 is passed through a relay lens 57 and a bending mirror 58 in this order, and then a condenser optical system 59.
And reticle R is irradiated with Koehler as illumination light IL. When the reticle R is illuminated with the illumination light IL, the image of the pattern DP formed on the reticle R is projected onto the wafer W via the projection optical system PL to transfer the pattern.

Next, another embodiment of the illumination optical system 7 provided in the exposure apparatus according to one embodiment of the present invention will be described. FIG. 11 is a diagram showing a configuration of another embodiment of the illumination optical system 7 included in the exposure apparatus according to the embodiment of the present invention. Although the illumination optical system 7 shown in FIG. 10 includes the first fly-eye lens 51 and the second fly-eye lens 53 as the optical integrator, the illumination optical system 7 shown in FIG. 11 has the first fly-eye lens 51 and the fly-eye lens 51. A rod integrator is used instead of the second fly-eye lens 53. Further, the illumination optical system 7 shown in FIG. 11 includes the diffusing plate 22, the driving device 23, the first rod lens 24, and
The relay optical system including the condenser lens 25, the second rod lens 26, and the relay lens 27 is applied to the illumination optical system 7.

The illumination optical system 7 shown in FIG. 11 includes a beam shaping optical system 60, a zoom optical system 61, a diffusing plate 62, a driving device 63, a first rod integrator 64, a condenser lens 65, a second rod integrator 66, and a visual field. The diaphragm plate 67, the relay lens 68, the bending mirror 69, and the condenser optical system 70 are included. The beam shaping optical system 60 shapes the cross-sectional shape of the laser light emitted from the light source 1 into a predetermined shape. It is assumed that the illumination optical system 7 shown in FIG. 11 also receives laser light having a wavelength of 200 nm or less from the light source 1. Beam shaping optics 6
The laser light that has passed through 0 enters the zoom optical system 61.

The zoom optical system 61 is composed of a lens 61a, an axicon prism including prisms 61b and 61c, and a lens 61d. The axicon prism can continuously change the magnification by adjusting the distance between the prism 61b and the prism 61c. These prisms 61a and 61b are used in the main control system 1
It is driven by a driving device (not shown) under the control of 8, and the position in the optical axis AX10 direction is adjusted. The lens 61a and the prisms 61b, 61 included in the zoom optical system 61
An aspherical surface is preferably formed on at least one lens surface of c and the lens 61d in order to minimize residual aberration.

The laser light transmitted through the zoom optical system 61 is incident on the diffusion plate 62. The diffusing plate 62 corresponds to the diffusing means in the present invention, and diffuses the laser light incident through the zoom optical system 61 to convert the light intensity distribution. The reason why the diffusion plate 62 is provided is to make the illuminance distribution of the illumination light IL applied to the reticle surface RP uniform. Further, the diffusion plate 62 is configured to be rotatable about a rotation axis that is set substantially parallel to the optical axis AX10, and the drive device 63 rotates the diffusion plate 62 around the rotation axis. Here, the reason why the diffusion plate 62 is configured to be rotatable around an axis parallel to the optical axis AX10 is to reduce the speckle of the illumination light IL irradiated on the reticle surface RP.

The laser light diffused by the diffusion plate 22 is
It enters the rod integrator 64. This first rod
The integrator 64 internally reflects the incident laser beam.
While leading to the injection end, the rod-like shape referred to in the present invention
It corresponds to an internal reflection type optical member. This 1st rod inte
The glass material forming the grater 64 is emitted from the light source 1.
Fluorite (calcium fluoride) depending on the wavelength of the laser light
Mu: CaF₂), Magnesium fluoride (MgF₂),
Lithium fluoride (LiF), barium fluoride (BaF₂),
Strontium fluoride (SrF₂), LiCAF (col
Kirite: LiCaAlF₆), LiSAF (LiSr
AlF₆), LiMgAlF₆, LiBeAlF₆, KM
gF₃, KCaF₃, KSrF₃Fluoride crystals or the like
Quartz doped with these mixed crystals or substances such as fluorine and hydrogen
It is selected from optical materials that transmit vacuum ultraviolet light such as glass.
It Quartz glass doped with a specified substance is
If the wavelength is shorter than about 150 nm, the transmittance will decrease.
Therefore, it illuminates vacuum ultraviolet light with a wavelength of about 150 nm or less.
When used as the light IL, it is used as an optical material of the optical element.
Fluorite (calcium fluoride), magnesium fluoride
System, lithium fluoride, barium fluoride, strontium fluoride
Lithium, LiCAF (corkyrite), LiSAF (L
iSrAlF₆), LiMgAlF₆, LiBeAl
F₆, KMgF₃, KCaF ₃, KSrF₃Fluoride formation of
Crystals or mixed crystals thereof are used. Also, the first rod
The sectional shape of the integrator 64 is shown in FIGS. 2 and 3.
Similar to the first rod lens 24, a circular shape, a rectangular shape, or
Is formed in a triangular shape.

In the structure shown in FIG. 11, a diffusion plate 62 for diffusing laser light is provided on the incident surface side of the first rod integrator 64. However, when the cross-sectional shape of the first rod integrator 64 is a rectangular shape or a triangular shape, it is conceivable that the illuminance distribution of the light flux emitted from the exit end of the first rod integrator 64 becomes uneven. In order to eliminate this illuminance unevenness and make the illuminance distribution uniform, a diffractive optical element that arbitrarily sets the illuminance distribution of laser light in a plane perpendicular to the optical axis AX10 according to the cross-sectional shape of the first rod integrator 64 is provided. It is preferable to provide instead of the diffusion plate 62 or together with the diffusion plate 62. Further, the optical axis AX20 of the first rod integrator 64 and the optical axis AX10 of the zoom optical system 61 and the like are set so as to satisfy a predetermined angle, for example, 4 ° ≦ θ ≦ 10 °.

The condenser lens 65 corresponds to the lens system according to the present invention, and the second rod integrator 66 corresponds to the second rod-shaped internal reflection type optical member according to the present invention. The front focus position of the condenser lens 65 is the first
The second rod integrator 66 is positioned so as to be disposed on the exit surface of the rod integrator 64, and the second rod integrator 66 is positioned so that the entrance surface is located at the back focal position of the condenser lens 65, and the entrance end and the exit end thereof are The ends are arranged so as to be substantially perpendicular to the optical axis AX20.
The condenser lens 65 arranged in this way is
The laser light emitted from the rod integrator 64 acts so as to Koehler-illuminate the incident surface of the second rod integrator 66.

The first rod integrator 64 and the second rod integrator 64
The first rod integrator 64 and the second rod integrator 66 are provided in the optical path between the rod integrator 66 and the rod integrator 66.
Compensation member for compensating relative displacement with (see FIG. 8)
Is preferably provided. Further, the cross-sectional shape of the second rod integrator 66 is arbitrarily selected from the shapes such as the circular shape, the rectangular shape, and the triangular shape shown in FIG. 2 or FIG. Is fluorite (calcium fluoride: CaF ₂ ), magnesium fluoride (MgF ₂ ), lithium fluoride (LiF), fluorinated according to the wavelength of the laser light emitted from the light source 1. Barium (BaF ₂ ),
Strontium fluoride (SrF ₂ ), LiCAF (corkyrite: LiCaAlF ₆ ), LiSAF (LiSr
AlF ₆ ), LiMgAlF ₆ , LiBeAlF ₆ , KM
It is selected from fluoride crystals such as gF ₃ , KCaF ₃ and KSrF ₃ or mixed crystals thereof, and optical materials such as quartz glass doped with substances such as fluorine and hydrogen, which transmit vacuum ultraviolet light.

The exit end of the second rod integrator 66 is set so as to be optically conjugate with the reticle surface RP of the reticle R, and the second rod integrator 66 is provided.
A field stop plate 67 is arranged at the exit end of the. The light flux emitted from the exit end of the second rod integrator 66 is the field stop pair 67, the relay lens 68, and the bending mirror 6.
9 and condenser optical system 70 in this order
The reticle surface RP is illuminated with the illumination light IL having a substantially uniform illuminance distribution.

The other embodiment of the illumination optical system 7 included in the exposure apparatus according to the embodiment of the present invention has been described above. However, as shown in FIG. 12, the illumination optical system 7 includes only one rod integrator. It may be. 12
FIG. 8 is a diagram showing a modified example of the illumination optical system 7 according to another embodiment of the present invention. The illumination optical system 7 shown in FIG.
A rod integrator 80 is provided instead of the first rod integrator 64, the condenser lens 65, and the second rod integrator 66 shown in FIG. In the illumination optical system 7 having the configuration shown in FIG. 12, the diffusion plate 62 is rotated to reduce speckles caused by the laser light having a narrow band, and the rod integrator 80 makes the illumination light IL uniform in illumination distribution. It has become. The material and sectional shape of the rod integrator 64 are the same as those of the first rod integrator 64 and the second rod integrator 66 shown in FIG.

Next, when manufacturing the exposure apparatus according to the embodiment of the present invention having the above-described structure, first, the light source 1, the illumination optical system 7, and the projection optical system PL are assembled with high accuracy. Next, the assembled light source 1, illumination optical system 7, and projection optical system PL, motor 8, reticle stage 9, laser interferometer 10, moving mirror 11, and T.
The reticle alignment system including the TR sensor 20 and each element such as the wafer holder 12, the wafer stage 13, the moving mirror 15, the laser interferometer 16, and the wafer alignment system including the motor 17 are electrically, mechanically, or optically connected. And assembled. Then, by performing the final comprehensive adjustment (electrical adjustment, operation check, etc.) so that the wafer W can be position-controlled accurately and at high speed, and exposure can be performed with high exposure accuracy while improving throughput. An exposure apparatus is manufactured. It is desirable that the exposure apparatus is manufactured in a clean room where the temperature and cleanliness are controlled.

Next, the overall operation of the exposure apparatus according to the embodiment of the present invention described above will be described. Figure 13
6 is a flowchart showing an operation example of an exposure apparatus which is a part of a method for manufacturing a micro device according to an embodiment of the present invention. When the operation starts, the reticle R is first placed on the reticle stage 9 (step S10). When the reticle R is placed on the reticle stage 9, the main control system 18 drives the motor 17 while monitoring the position measurement signal output from the laser interferometer 16 to move the wafer stage 13 in the XY plane and set the reference. The member 14 is arranged at a predetermined position.
The predetermined position where the reference member 14 is arranged is a position where the TTR sensor 20 can observe the reticle mark RM and the wafer mark WM via the projection optical system PL in a substantially overlapping state. When laser light is emitted from the light source 1 in this state, the emitted laser light is reflected by the half mirror 5 and guided to the TTR sensor 20 via the relay optical system. The laser beam guided to the TTR sensor 20 has a field diaphragm plate 28, a relay lens 29, a beam splitter 30,
And the bending mirror 3 through the first objective lens 31 in order.
The reticle alignment mark RM formed on the reticle R is illuminated by being incident on the beam 2 and being deflected in the −Z direction. The alignment light transmitted through the reticle alignment mark RM illuminates the reference mark formed on the reference member 14 provided on the wafer stage 13 as the substrate stage via the projection optical system PL.

The reflected light, the diffracted light, and the scattered light obtained by illuminating the reference mark with the alignment light follow the optical path of the alignment light in the reverse order to reach the reticle alignment mark RM, and are reflected by this light and the reticle alignment mark RM. The reflected light is combined and incident on the bending mirror 32 and is deflected in the -X direction. Then, it is reflected by the beam splitter 30 via the first objective lens 31. The light reflected by the beam splitter 30 is reflected by the reflection mirror 33 and deflected in the −X direction, then is condensed by the second objective lens 34 and is incident on the image pickup surface of the image pickup device 35. Image sensor 35
Is the main control system 1 as an image signal obtained by photoelectrically converting the optical image of the reticle alignment mark RM and the optical image of the reference mark.
Output to 8. The main control system 18 performs image processing on the image signal output from the image pickup device 35 to measure the positional deviation between the reticle alignment mark RM and the reference mark (step S12), and the pattern DP formed on the reticle R is measured. A reference position (for example, a position at which the center of the pattern is projected: hereinafter referred to as a projection center) at which the optical image of is projected by the projection optical system PL is obtained (step S14).

Next, the main control system 18 uses the wafer stage 1
3 is moved to dispose the reference member 14 in the measurement visual field of the off-axis alignment system 19, and the off-axis alignment system 19 positions the reference mark in the detection visual field (for example, the center position of the reference mark with respect to the center of the visual field). A deviation amount) is obtained (step S16). Wafer stage 13
Since the position of is always measured by the laser interferometer 16,
After the above processing is completed, the distance (so-called baseline amount) between the projection center and the visual field center of the off-axis alignment system 19 is calculated (step S18). When the above processing is completed, the wafer W carried in is placed on the wafer holder 12 (step S20), and the position information of the wafer alignment mark WM formed on the wafer W is measured using the off-axis alignment system 19 ( Step S22).

When the measurement of the position information of the wafer alignment mark WM is completed, the main control system 18 performs a statistical calculation process called so-called enhanced global alignment (EGA) measurement, and the shot set on the wafer W. The array coordinates of the area are calculated (step S24). next,
The main control system 18 determines the position of one shot area of the wafer W and the position where the pattern of the reticle R is irradiated, based on the array coordinates of the shot areas obtained by EGA measurement and the baseline amount obtained in advance. Matching (Step S2
6).

When the alignment of the shot area to be exposed is completed, the main control system 18 determines the motor 8 and the motor 8 based on the signal output from the laser interferometer 10 and the position measurement signal output from the laser interferometer 16. The reticle stage 9 and the wafer stage 13 are moved along the X direction via the motor 17. When the relative position between the reticle R and the wafer W has a predetermined relationship, the main control system 18 causes the reticle R to move.
The area defined by the reticle blind 56 above is uniformly illuminated, and then the reticle R and the wafer W are constantly illuminated.
And are synchronously scanned to sequentially transfer the pattern DP formed on the reticle R onto the wafer W (step S28). When the exposure for one shot area is completed, the main control system 1
Reference numeral 8 steps the wafer stage 13 through the motor 17 to expose another shot area. By repeating such an operation, the exposure processing is performed on all the shot areas set on the wafer W.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be freely modified within the scope of the present invention. For example, although the step-and-scan type exposure apparatus has been described as an example in the above-described embodiment, the step-and-repeat type exposure apparatus and the reticle and the wafer are brought into close contact with each other without using the projection optical system PL. The present invention can also be applied to a proximity exposure apparatus that transfers a reticle pattern onto a wafer. Further, in the above-described embodiment, the ArF excimer laser light source or the F ₂ laser light source is used as the light source 1, but the present invention is not limited to this. For example, a Kr ₂ laser light source with a wavelength of 146 nm, A vacuum ultraviolet light source such as an Ar ₂ laser light source having a wavelength of 126 nm may be used. In such a case, it is possible to further improve the resolution by pulsed ultraviolet light having a shorter wavelength, and thus to perform exposure with higher accuracy.

Further, the TTR sensor 20 provided in the exposure apparatus of the above-described embodiment has the reticle alignment mark RM formed on the reticle R and the wafer alignment mark WM formed on the wafer W or the reference member 1.
The reference mark formed in No. 4 was observed at the same time. However, the present invention is not limited to the TTR sensor 20. For example, a TTL (through, The·
It can also be applied to a (lens) type alignment sensor.

FIG. 14 is a view showing the arrangement of an exposure apparatus having a TTL sensor as a position measuring device. In FIG. 14, reference numeral 90 is attached to the TTL sensor. This T
The configuration of the TL sensor 90 is the TTR sensor 20 shown in FIG.
Is almost the same as. However, since the TTL sensor 90 is arranged below the reticle stage 9, the field stop plate 28 is
And the first surface so that the image pickup surface of the image pickup device 25 and the reference pattern formed on the reference member 14 are optically conjugated.
The difference is that the focal lengths of the objective lens 31 and the second objective lens 34 are designed. The TTL sensor having such a configuration observes the reference mark or the wafer alignment mark WM formed on the reference member 14 via the projection optical system PL to thereby obtain the information on the reference position of the wafer stage 13 or the position information of the wafer W. measure.

FIG. 15 is a diagram showing another configuration example in which the laser light is incident on the first rod lens 24 from an oblique direction. In the above-described embodiment, the first rod lens 24 set substantially parallel to the X axis as shown in FIG.
The optical axis AX1 of the relay lens 21 is tilted with respect to the optical axis AX2, and the angle of the half mirror 5 is adjusted so that the laser light travels in the optical axis AX1 direction. However, as shown in FIG. 15B, the optical axis AX1 of the relay lens 21 is set to be substantially parallel to the X axis, and the half mirror 5 is adjusted so as to reflect the incident laser light in the substantially X direction. Then, the rod lens 24
The optical axis AX2 may be inclined with respect to the optical axis AX1. In addition, in FIGS. 15A and 15B,
Although the diffuser plate 22 is arranged perpendicularly to the optical axis AX1, it may be arranged to be inclined with respect to the optical axis AX1, as shown in FIG. Further, as shown in FIG. 15D, the optical axis AX1 and the optical axis AX2 may be set parallel to each other, and one of the relay lenses 21 may be arranged so as to be decentered from the optical axis AX1.

The relay optical system shown in FIG. 1 has been described by taking the one including the first rod lens 24 and the second rod lens 26 as an example. However, the illumination optical system 7 shown in FIG.
Similarly, the configuration may be such that only one rod lens is provided. Further, in the relay optical system shown in FIG. 1, the diffuser plate 22 is arranged in order to equalize the illuminance distribution of the alignment light IL1 with which the reticle R is irradiated.
Alignment light IL1 having a uniform illuminance distribution without providing 2
The configuration may be such that the diffusion plate 22 is omitted as long as the above is obtained.

Furthermore, the illumination optical system 7 shown in FIGS. 11 and 12, the relay optical system for guiding the laser light to the TTR sensor 20 shown in FIG. 1, and the relay for guiding the laser light to the TTL sensor 90 shown in FIG. In the optical system, the diffusion plates 22 and 62 may not always be rotated, but the diffusion plates 22 and 62 may be rotated only when the laser light from the light source 1 is narrowed and speckles are generated. . In other words, when the laser light from the light source 1 has a wide band and the generation of speckles is small, it is not necessary to rotate the diffusion plate 22.62.

Furthermore, in the above embodiment, the case where the reference mark or the wafer alignment mark WM formed on the reference member 14 is illuminated via the projection optical system PL has been described as an example. However, the laser light from the light source 1 is guided below the reference member 14 via the rod lens,
The present invention is also applied to a sensor that illuminates a reference mark formed on the reference member 14 using this laser light and observes an optical image obtained by illuminating the reference mark via the projection optical system PL. You can

Further, in the illumination optical system 7 shown in FIG. 10, the fly-eye lens (the first fly-eye lens 51 and the second fly-eye lens 53) is used as the optical integrator (homogenizer). An optical element, a microlens array, or the like may be used. Also, fly-eye lens and rod
The configuration may be combined with an integrator. Furthermore, a double integrator may be configured by combining a diffractive optical element and a rod integrator or a microlens array.

The exposure apparatus of the above-described embodiment is used not only when it is used for manufacturing a semiconductor element, but also when it is used for manufacturing a display including a liquid crystal display element or the like and a device pattern is formed on a glass substrate. Used for manufacturing a thin film magnetic head, a device pattern transferred on a ceramic wafer, and a CCD.
It can also be used when manufacturing an image pickup device such as.

Further, for example, even in the exposure apparatus using the ultraviolet light as in the above-mentioned embodiment, the projection system PL is a reflection system including only reflection optical elements or a reflection optical element having a reflection optical element and a refraction optical element. A refraction system (catadioptric system) may be adopted. Here, as the catadioptric projection optical system, for example, JP-A-8-171054 (and corresponding US Pat. No. 5,668,672) can be used.
No.), and Japanese Patent Laid-Open No. 10-20195 (and corresponding US Pat. No. 5,835,275) and the like, a catadioptric system having a beam splitter and a concave mirror as catoptric optical elements, or Kaihei 8-334695 (and corresponding US Pat. No. 5,689,37)
No. 7), and Japanese Patent Laid-Open No. 10-3039 (and corresponding European Patent Publication No. 816,892), such as a catadioptric system having a concave mirror without using a beam splitter as a catoptric element. Can be used.

In addition, a plurality of refracting optical elements and two mirrors (a main mirror which is a concave mirror and a refracting element) disclosed in Japanese Patent Laid-Open No. 10-104513 (and US Pat. No. 5,488,229). Or, a parallel mirror and a secondary mirror, which is a rear surface mirror having a reflecting surface formed on the side opposite to the entrance surface, are arranged on the same axis, and an intermediate image of the reticle pattern formed by the plurality of refractive optical elements is arranged. A catadioptric system that re-images on the wafer by the primary mirror and the secondary mirror may be used. In this catadioptric system, a primary mirror and a secondary mirror are arranged following a plurality of refractive optical elements, and illumination light is reflected through the part of the primary mirror in the order of the secondary mirror and the primary mirror. To reach on the wafer.

Further, as a catadioptric projection optical system,
For example, with a circular image field and on the object side,
It is also possible to use a reduction system in which both the image side and the image side are telecentric and the projection magnification is ¼ or ⅕. Further, in the case of a scanning type exposure apparatus equipped with this catadioptric projection optical system, the irradiation area of the illumination light is substantially centered on its optical axis within the field of view of the projection optical system, and is almost in the scanning direction of the reticle or wafer. It may be of a type defined in a rectangular slit shape extending along a direction orthogonal to each other. According to the scanning type exposure apparatus provided with such a catadioptric projection optical system, even if F ₂ laser light having a wavelength of 157 nm is used as the illumination light for exposure, a fine pattern of about 100 nm L / S pattern can be highly accurately formed on the wafer. Can be transferred to.

Further, ArF excimer laser light, F ₂ laser light, or the like is used as the vacuum ultraviolet light, and a single-wavelength laser light in the infrared region or the visible region oscillated from the DFB semiconductor laser or fiber laser, such as erbium, is used. (Or both erbium and ytterbium) may be used for amplification by a fiber amplifier doped, and a harmonic converted into ultraviolet light using a nonlinear optical crystal may be used. For example, assuming that the oscillation wavelength of the single-wavelength laser is within the range of 1.51 to 1.59 μm, the 8th harmonic with the generation wavelength within the range of 189 to 199 nm, or the generation wavelength of 151 to 159 nm.
The 10th harmonic within the range is output. In particular, when the oscillation wavelength is within the range of 1.544 to 1.553 μm, the 8th harmonic within the range of the generated wavelength within the range of 193 to 194 nm, that is, the ultraviolet light having substantially the same wavelength as the ArF excimer laser light is obtained, and the oscillation is generated. When the wavelength is within the range of 1.57 to 1.58 μm, the generated wavelength is 1 within the range of 157 to 158 nm.
The 0th harmonic, that is, the ultraviolet light having substantially the same wavelength as that of the F ₂ laser light can be obtained. In addition, the oscillation wavelength is 1.03 to 1.12
Generated wavelength is 147 ~ 160nm
7 times higher harmonic within the range of, and particularly when the oscillation wavelength is within the range of 1.099 to 1.106 μm, the 7th higher harmonic within the range of 157 to 158 μm, that is, F
2 Ultraviolet light with almost the same wavelength as the laser light can be obtained. In this case, as the single wavelength oscillation laser, for example, an ytterbium-doped fiber laser can be used.

Further, in order to manufacture a reticle or a mask used in not only a microdevice such as a semiconductor element but also an optical exposure apparatus, an EUV exposure apparatus, an X-ray exposure apparatus, an electron beam exposure apparatus, etc., a glass substrate or The present invention can be applied to an exposure apparatus that transfers a circuit pattern onto a silicon wafer or the like. Here, a transmissive reticle is generally used in an exposure apparatus that uses DUV (far ultraviolet) light, VUV (vacuum ultraviolet) light, or the like, and quartz glass is used as a reticle substrate.
Fluorine-doped quartz glass, fluorite, magnesium fluoride, quartz, or the like is used. Further, in a proximity type X-ray exposure apparatus or an electron beam exposure apparatus, a transmissive mask (stencil mask, membrane mask)
Is used, and a silicon wafer or the like is used as the mask substrate.

Next, an embodiment of a method of manufacturing a micro device using the exposure apparatus according to the embodiment of the present invention in a lithography process will be described. FIG. 16 is a flowchart of a method for obtaining a semiconductor device as a micro device. First, in step S30 of FIG. 16, a metal film is deposited on one lot of wafers. In the next step S32, a photoresist is applied on the metal film on the wafer of the one lot. Thereafter, in step S34, the exposure apparatus shown in FIG. 1 is used to sequentially expose and transfer the image of the pattern on the mask M to each shot area on the wafer of the one lot through the projection optical system PL.

Then, in step S36,
After the development of the photoresist on the lot of wafers, the circuit pattern corresponding to the pattern on the mask is formed on each wafer by performing etching with the resist pattern on the wafer of the one lot in step S38. It is formed in each upper shot area. After that, a device such as a semiconductor element is manufactured by forming a circuit pattern on an upper layer. According to the above-described semiconductor device manufacturing method, it is possible to obtain a semiconductor device having an extremely fine circuit pattern with high throughput.

Further, in the exposure apparatus shown in FIG. 1, a liquid crystal display element as a microdevice can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). Less than,
An example of the technique at this time will be described with reference to the flowchart in FIG. FIG. 17 is a flowchart of a method for obtaining a liquid crystal display element as a microdevice by forming a predetermined pattern on a plate using the exposure apparatus of this embodiment.

In the pattern forming step S40 shown in FIG.
A so-called photolithography process is performed in which the exposure apparatus of the present embodiment is used to transfer and expose the pattern of the mask onto a photosensitive substrate (such as a glass substrate coated with a resist). By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Then, the exposed substrate is subjected to a developing process, an etching process, a reticle peeling process, and the like to form a predetermined pattern on the substrate.
Move to 42.

Next, in the color filter forming step S42, R (Red), G (Green), B (Blue)
A plurality of sets of three dots corresponding to the above are arranged in a matrix, or a set of filters of three stripes of R, G, and B are arranged in the horizontal scanning line direction to form a color filter. Then, the color filter forming step S42
After that, the cell assembling step S44 is executed. In the cell assembly step S44, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step S40, the color filter obtained in the color filter formation step S42, and the like.

In the cell assembling step S44, for example, a liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern forming step S40 and the color filter obtained in the color filter forming step S42 to form a liquid crystal panel. (Liquid crystal cell) is manufactured. After that, the module assembly step S4
At 6, the components such as the electric circuit and the backlight for performing the display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete the liquid crystal display element. According to the method of manufacturing a liquid crystal display element described above, a liquid crystal display element having an extremely fine circuit pattern can be obtained with high throughput.

If the microdevice manufacturing method of this embodiment described above is used, the above-mentioned exposure apparatus and the above-described exposure method are used in the exposure step (step S34), and the resolution is improved by the illumination light in the vacuum ultraviolet region. Moreover, since the exposure amount can be controlled with high precision, as a result, a highly integrated device having a minimum line width of about 0.1 μm can be produced with a high yield.

[0094]

As described above, according to the present invention, after the light emitted from the light source and having a wavelength of 200 nm or less is diffused by the rotating diffusing means, the diffused light is internally reflected in the rod shape. The mold optical member is guided while being internally reflected. Here, since the diffusing means is rotated, there is an effect that the speckle on the irradiated surface can be reduced even if the light from the light source is narrowed. In addition, since the diffused light is diffused by the diffusing means and then is made incident on the rod-shaped internal reflection type optical member, it is reflected and guided at various angles inside the rod-shaped internal reflection type optical member. As a result, it is possible to obtain illumination light having a uniform illuminance distribution. In addition, since a rod-type internal reflection type optical member is used to guide the light from the light source, there is a high degree of freedom in how to guide the laser light according to the device configuration, and strict optical adjustment accuracy is required. Since the adjustment is not performed, the adjustment is easy, and as a result, the cost required for the adjustment, and thus the cost of the illumination optical system and the exposure apparatus can be reduced. Further, there is an effect that the relative position between the mask and the substrate can be detected with high accuracy by using the light that has a substantially uniform illuminance distribution and has a short wavelength and which is transmitted through the projection optical system.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an entire exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a first rod lens 24.

FIG. 3 is a perspective view showing an example of a first rod lens 24.

FIG. 4 is a diagram showing a positional relationship between a diffusion plate 22 and a first rod lens 24.

FIG. 5 is a diagram showing an example of a state of a light beam emitted from an emission surface when laser light is incident on the incident surface of the first rod lens 24 from an oblique direction.

FIG. 6 is a diagram showing an example of diffusion characteristics along the Y-axis direction of a diffusion plate 22 having a circular cross section.

FIG. 7 is a diagram showing how the incident surface of the second rod lens 26 is subjected to Koehler illumination.

FIG. 8 shows a first rod lens 24 and a second rod lens 2.
6 is a diagram showing a configuration example of a correction member that corrects a relative displacement with respect to FIG.

FIG. 9 is a diagram for explaining how laser light emitted from a light source 1 is converted into alignment light having a uniform illuminance distribution via a relay optical system and a TTR sensor.

FIG. 10 is a diagram showing a configuration of an illumination optical system 7 included in the exposure apparatus according to the embodiment of the present invention.

FIG. 11 is a diagram showing the configuration of another embodiment of the illumination optical system 7 included in the exposure apparatus according to the embodiment of the present invention.

FIG. 12 is an illumination optical system 7 according to another embodiment of the present invention.
It is a figure which shows the modification of.

FIG. 13 is a flowchart showing an operation example of the exposure apparatus which is a part of the method for manufacturing a microdevice according to the embodiment of the present invention.

FIG. 14 is a diagram showing a configuration of an exposure apparatus including a TTL sensor as a position measuring device.

FIG. 15 is a diagram showing another configuration example in which laser light is incident on the first rod lens 24 from an oblique direction.

FIG. 16 is a flowchart of a method for obtaining a semiconductor device as a micro device.

FIG. 17 is a flowchart of a method for obtaining a liquid crystal display element as a microdevice by forming a predetermined pattern on a plate using the exposure apparatus of this embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 light source 5 half mirror (illumination optical system) 7 illumination optical system 13 wafer stage (substrate stage) 14 reference member (irradiated object) 20 TTR sensor (position measuring device) 21 relay lens (illumination optical system) 22 diffuser plate (illumination) Optical system, diffusing means 23 Drive device (illumination optical system) 24 First rod lens (illumination optical system, rod-shaped internal reflection type optical member, first rod-shaped internal reflection type optical member) 25 Condenser lens (illumination Optical system, lens system 26 Second rod lens (illumination optical system, rod-shaped internal reflection type optical member, second rod-shaped internal reflection type optical member) 27 Relay lens (illumination optical system) 28 Field diaphragm plate ( Illumination optical system) 29 Relay lens (illumination optical system) 30 Beam splitter (illumination optical system) 31 First objective lens (illumination optical system) 32 Bending mirror (Illumination optical system) 40 to 43 Bending mirror (correction member) 62 Diffusion plate (diffusion means) 64 First rod integrator (rod-shaped inner reflection type optical member, first rod-shaped inner reflection type optical member) 65 Condenser Lens (lens system) 66 Second rod integrator (rod-shaped inner reflection type optical member, second rod-shaped inner reflection type optical member) 80 Rod integrator (rod-shaped inner reflection type optical member) 90 TTL sensor (position) Measuring device) DP pattern IL Illumination light IL1 Alignment light (illumination light) PL Projection optical system R Reticle (irradiated object, mask) W Wafer (irradiated object, substrate)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02B 19/00 G03F 7/20 521 G03F 7/20 521 H01L 21/30 525R F term (reference) 2F065 AA14 AA20 BB17 BB27 CC17 DD03 FF41 GG04 HH12 JJ03 JJ08 JJ26 LL10 PP12 2H042 BA01 BA12 BA14 BA16 2H049 AA55 AA64 AA69 2H052 BA02 BA03 BA08 BA09 BA12 5F046 BA04 CA03 CC16 FA05 FB10 FB11 FB12 FC05

Claims (21)

[Claims] 1. An illumination optical system for irradiating an object to be illuminated with light emitted from a light source, wherein the wavelength of light emitted from the light source is 200 nm or less, and an optical path between the light source and the object to be illuminated. A diffusing unit that is disposed inside and diffuses the light emitted from the light source, and that is configured to be rotatable, and is disposed in an optical path between the diffusing unit and the irradiated object to diffuse the light. An illumination optical system, comprising: at least one rod-shaped internal reflection type optical member that guides the diffused light diffused by the means while internally reflecting the diffused light. 2. The illumination optical system according to claim 1, wherein the rod-shaped internal reflection type optical member has a circular cross section. 3. The illumination optical system according to claim 1, wherein the rod-shaped internal reflection type optical member has a rectangular cross section. 4. The diffusing means includes a diffractive optical element that forms a predetermined illuminance distribution according to the cross-sectional shape of the rod-shaped inner surface reflection type optical member. Illumination optics. 5. The incident surface of the rod-shaped internal reflection type optical member is arranged at a predetermined angle with respect to the light incident on the diffusing means. The illumination optical system according to item 1. 6. A lens system in which a front focal position is arranged on the exit surface of the rod-shaped internal reflection type optical member, and a second system in which an incident surface is arranged at the rear focal position of the lens system.
6. The illumination optical system according to claim 1, further comprising: a rod-shaped inner surface reflection type optical member. 7. The correction member for correcting relative positional deviation between the rod-shaped inner surface reflection type optical member and the second rod-shaped inner surface reflection type optical member is further provided. Illumination optical system described. 8. An illumination optical system for irradiating an object to be illuminated with light emitted from a light source, wherein the wavelength of light emitted from the light source is 200 nm or less, and an optical path between the light source and the object to be illuminated. A diffusing unit disposed inside and diffusing the light emitted from the light source, and a diffusing light diffused by the diffusing unit disposed in an optical path between the diffusing unit and the irradiation object. A first rod-shaped inner reflection type optical member that guides the light to the emission surface while reflecting the inner surface, and is arranged in an optical path between the first rod-shaped inner reflection type optical member and the irradiation target, and is incident. A second rod-shaped inner reflection type optical member that guides light to the exit surface while internally reflecting the light; a first rod-shaped inner reflection type optical member; and a second rod-shaped inner reflection type optical member. Equipped with a lens system arranged in the optical path between The front focal position of the lens system is positioned at the exit surface of the first rod-shaped internal reflection optical member, and the rear focal position of the lens system is the second rod internal reflection optical member. An illumination optical system characterized in that it is positioned on the incident surface of the. 9. An exposure apparatus for transferring a pattern formed on a mask onto a substrate, the substrate stage holding the substrate, and illuminating at least a part of the mask as the object to be illuminated with illumination light. An exposure apparatus comprising: the illumination optical system according to any one of claims 1 to 8. 10. An exposure apparatus for transferring a pattern formed on a mask onto a substrate via a projection optical system, a substrate stage holding the substrate, and a reference provided on the substrate stage as the object to be illuminated. The position of the substrate stage is measured by observing the reference member via the illumination optical system according to any one of claims 1 to 8 which irradiates a member with illumination light, and the projection optical system. An exposure apparatus comprising a position measuring device. 11. A stage position measuring step of measuring the position of the substrate stage using a position measuring device provided in the exposure apparatus according to claim 10, and the substrate stage based on a measurement result of the stage position measuring step. An adjusting step of adjusting a relative position with respect to the mask; a transfer step of irradiating the mask with illumination light to transfer the pattern formed on the mask onto the substrate through the projection optical system; And a developing step of developing the substrate transferred by the above method. 12. An exposure apparatus for transferring a pattern formed on a mask onto a substrate via a projection optical system, a light source for emitting light having a wavelength of 200 nm or less, and holding the substrate and defining a reference position. A substrate stage having a reference member, and arranged in the optical path between the light source and the reference member,
At least one rod-shaped internal reflection optical member that internally reflects the light from the light source and guides it to the exit side, and the reference based on the light that has passed through the rod-shaped internal reflection optical member and the projection optical system. An exposure apparatus, comprising: a position measuring device that detects a member. 13. The cross-sectional shape of the rod-shaped internal reflection type optical member is circular.
The exposure apparatus described. 14. The cross-sectional shape of the rod-shaped internal reflection type optical member is a rectangular shape.
The exposure apparatus described. 15. A diffusion means for diffusing light emitted from the light source is further provided in an optical path between the light source and the rod-shaped inner surface reflection type optical member. The exposure apparatus according to any one of 1. 16. The exposure apparatus according to claim 15, wherein the incident surface of the rod-shaped internal reflection type optical member is arranged at a predetermined angle with respect to the light incident on the diffusing means. 17. The exposure apparatus according to claim 15, wherein the diffusing unit is configured to be rotatable about a direction parallel to a traveling direction of light emitted from the light source as an axis. 18. A lens system having a front focus position on the exit surface of the rod-shaped internal reflection type optical member, and a second lens system having an entrance surface at the rear focus position of the lens system.
18. The exposure apparatus according to any one of claims 12 to 17, further comprising: a rod-shaped internal reflection type optical member. 19. A correction member for correcting relative positional displacement between the rod-shaped inner surface reflection type optical member and the second rod-shaped inner surface reflection type optical member. The exposure apparatus described. 20. The position measuring device detects a mark on the mask based on light transmitted through the rod-shaped internal reflection type optical member, and measures a relative positional relationship between the substrate stage and the mask. 13. The method according to claim 12, wherein
20. The exposure apparatus according to claim 19. 21. A position measuring step of measuring a relative positional relationship between the substrate stage and the mask using a position measuring device provided in the exposure apparatus according to claim 20, and based on a measurement result of the position measuring step, An adjusting step of adjusting a relative position between the substrate stage and the mask, and a transfer step of irradiating the mask with illumination light to transfer an image of a pattern formed on the mask onto the substrate through the projection optical system. And a developing step of developing the substrate on which the pattern image is transferred in the transferring step.