JP6761574B2 - Illumination optics, exposure equipment, and device manufacturing methods - Google Patents

Description

Illumination optics, exposure equipment, and device manufacturing methods.

In an exposure apparatus used for manufacturing a device such as a semiconductor element, it is required to accurately transfer a pattern onto a wafer. Then, in order to accurately transfer this pattern onto the wafer, it is required to obtain a uniform illuminance distribution (exposure amount distribution) on the wafer.

However, when the coherence of the light supplied from the light source is high, that is, when a high coherence light source is used, the irradiated surface (projection optical system) of the illumination optical system is caused by interference between the lenslets constituting the fly-eye lens. An uneven illuminance distribution is formed on the object surface of the lens. Conventionally, a method of averaging the integrated illuminance distribution by randomly superimposing non-uniform illuminance distributions using a plurality of pulsed lights has been proposed (see, for example, Patent Document 1).

In the method of randomly superimposing non-uniform illuminance distributions, it is necessary to superimpose a large amount of light in order to average the integrated illuminance distribution.

U.S. Pat. No. 6,552,774

In the first embodiment, in the illumination optical system that illuminates the irradiated surface with the light from the light source,
A spatial light modulator that spatially modulates and emits light incident from the light source,
A relay optical system arranged in the optical path of light from the spatial light modulator,
An optical integrator having a plurality of wave plane dividing elements arranged in parallel in the optical path of light from the relay optical system, and
A condenser optical system that superimposes a plurality of light fluxes divided by the optical integrator on the irradiated surface is provided.
The length of the region for emitting light on the spatial light modulator along the first direction is set to form an illuminance distribution having a period in the first direction on the irradiated surface. Provides an optical system.

The second aspect provides an exposure apparatus that includes the illumination optical system of the first form that illuminates a pattern forming portion that forms a predetermined pattern, and exposes the predetermined pattern to a substrate.

In the third embodiment, the predetermined pattern is exposed to the substrate by using the exposure apparatus of the second embodiment.
The substrate to which the predetermined pattern is transferred is developed, and a mask layer having a shape corresponding to the predetermined pattern is formed on the surface of the substrate.
Provided is a device manufacturing method including processing the surface of the substrate via the mask layer.

It is a figure which shows schematic structure of the exposure apparatus which concerns on 1st Embodiment. It is a figure which shows schematic the internal structure of the delay optical system. It is a figure which shows the appearance that the circular light intensity distribution is formed on the surface of the micro fly eye lens on the incident side. It is a figure explaining the structure and operation of the spatial light modulator for variable pattern formation. It is a partial perspective view of the main part of a spatial light modulator. It is a figure explaining the conventional method which randomly superimposes a non-uniform illuminance distribution at random. It is a figure explaining the method of embodiment which superimposes the periodic illuminance distribution while shifting the position according to the movement width corresponding to the period. It is a figure which shows the optical path between a diffractive optical element and a mask blind surface developed linearly along an optical axis. It is a figure explaining the homogenizing action of the integrated illuminance distribution in 1st Embodiment. It is a figure which shows the example of the internal structure of the shift part schematicly. It is a figure which compares the conventional method and the method of an embodiment. It is a figure which shows the relationship between the length of the light emission region from a diffractive optical element and the contrast of an integrated illuminance distribution in an embodiment. It is a figure which shows schematic structure of the exposure apparatus which concerns on 2nd Embodiment. It is a figure explaining the structure and operation of the spatial light modulator for forming a pupil intensity distribution. It is a figure which shows the example of the internal structure of the tilt part schematicly. It is a figure which shows schematic the internal structure of the shift part which concerns on the modification. It is a flowchart which shows the manufacturing process of a semiconductor device. It is a flowchart which shows the manufacturing process of the liquid crystal device such as a liquid crystal display element.

Hereinafter, embodiments will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing a configuration of an exposure apparatus according to a first embodiment. In FIG. 1, the X-axis is set in the direction perpendicular to the paper surface, the Y-axis is set in the vertical direction on the paper surface of FIG. 1, and the Z-axis is set in the horizontal direction on the paper surface of FIG. The transfer surface (exposed surface) of the wafer W, which is a photosensitive substrate, is set parallel to the XZ plane. The exposure apparatus according to the first embodiment is a maskless type exposure apparatus using a spatial light modulator (SLM) for forming a variable pattern.

Referring to FIG. 1, exposure light (illumination light) is supplied from the light source unit LS to the exposure apparatus of the first embodiment. Examples of the light source LS include US Pat. No. 5,838,709B1, US Pat. No. 6,590,698B1, US Pat. No. 6,901,090B1, US Pat. No. 6,947,123B1. No., US Pat. No. 7,098,992B2, US Pat. No. 7,397,598B2, US Pat. No. 7,136,402B1, US Patent Publication No. 2006/050748A1 and As disclosed in U.S. Patent Publication No. 2009/185583A1, etc., it includes a solid-state laser light source such as a DFB semiconductor laser or fiber laser, an optical amplification unit having a fiber amplifier, a wavelength conversion unit, and the like, and has a wavelength of 193 nm. A harmonic generator that outputs pulsed light may be used.

The high-coherence pulsed light supplied from the light source unit LS enters the diffractive optical element 3 via the delay optical system 1, the beam light transmitting unit 2, and the optical path bending mirror MR1. Here, the high coherence light can be light having a number of transverse modes smaller than the number of transverse modes of the laser light supplied by the excimer laser light source.

As shown in FIG. 2, the delay optical system 1 includes a half mirror 11a provided on the incident side of the light. One pulsed light L1 supplied from the light source unit LS is divided into transmitted light L11 and reflected light L12 by the half mirror 11a. The light L11 transmitted through the half mirror 11a travels straight and is incident on another half mirror 11b.

The light L12 reflected by the half mirror 11a enters the half mirror 11b through an optical path in which the pair of mirrors 12a and 12b are arranged, that is, a delayed optical path longer than the optical path of the light L11. The light L11 is divided into transmitted light L111 and reflected light L112 by the half mirror 11b. The light L111 transmitted through the half mirror 11b travels straight and is incident on the polarizing beam splitter 13. The light L112 reflected by the half mirror 11b enters the polarizing beam splitter 13 through an optical path in which the pair of mirrors 12c and 12d and the half-wave plate 14 are arranged, that is, a delayed optical path longer than the optical path of the light L111.

On the other hand, the light L12 reflected by the half mirror 11a and passing through the delayed optical path including the mirrors 12a and 12b is divided into transmitted light L122 and reflected light L121 by the half mirror 11b. The light L122 transmitted through the half mirror 11b enters the polarization beam splitter 13 through the same delayed optical path as the light L112. The light L121 reflected by the half mirror 11b is incident on the polarizing beam splitter 13 through the same straight optical path as the light L111. The pulsed light L1 supplied from the light source unit LS is set to p-polarized light with respect to the polarization separation surface 13a of the polarization beam splitter 13.

Therefore, the p-polarized light L111 and L121 incident on the polarizing beam splitter 13 without passing through the half-wave plate 14 pass through the polarizing beam splitter 13 and are emitted from the delayed optical system 1 along substantially the same optical path as each other. .. The s-polarized light L112 and L122 incident on the polarization beam splitter 13 through the half-wave plate 14 are reflected by the polarization beam splitter 13 and emitted from the delay optical system 1 along substantially the same optical path as the light L111 and L121. ..

Here, the light L111 transmitted through the pair of half mirrors 11a and 11b is emitted from the delayed optical system 1 through the shortest optical path. The light L112 transmitted through the half mirror 11a and reflected by the half mirror 11b is emitted through the second shortest optical path. The light L121 reflected by the pair of half mirrors 11a and 11b is emitted through the third shortest optical path. The light L122 reflected by the half mirror 11a and transmitted through the half mirror 11b is emitted through the longest optical path.

In this way, the delay optical system 1 constitutes a generation unit that repeats the operation of generating four time-multiplexed pulse lights L111, L112, L121, and L122 from one pulse light L1 supplied from the light source unit LS. are doing. Note that FIG. 2 illustrates a configuration in which four time-multiplexed pulsed lights are generated from one incident pulsed light, but a half mirror as a dividing member and a pair of mirrors (if necessary, if necessary). By attaching a pair with a delayed optical path having a pair of relay lenses (including a pair of relay lenses), it is possible to generate a desired number of pulsed lights multiplexed in time.

Hereinafter, in order to facilitate understanding of the explanation, a large number of pulsed lights having the same light intensity as each other are emitted at regular time intervals by the cooperative action of the light source unit LS and the delayed optical system 1. To do. In other words, the light source unit LS and the delay optical system 1 supply pulsed light having an intensity smaller than the intensity of the pulsed light output by the light source unit LS according to a period shorter than the period in which the light source unit LS outputs pulsed light. It constitutes a light source unit.

The beam light transmitting unit 2 guides the light beam incident through the light source unit LS and the delayed optical system 1 to the diffractive optical element 3 while converting it into a luminous flux having a cross section of an appropriate size and shape, and incident on the diffractive optical element 3. Actively corrects the position fluctuation and angle fluctuation of the light. The beam light transmitting unit 2 sets the cross-sectional shape of the light beam incident on the diffractive optical element 3 as a spatial light modulator to a predetermined cross-sectional shape, so that the region where light is emitted on the diffractive optical element 3 has a predetermined shape. To. For details of the beam light transmitting unit 2, US Patent Publication No. 2012/0028197 and the like can be referred to. A diaphragm having an opening having a predetermined shape may be used in order to form a region where light is emitted on the diffraction optical element 3 as a spatial light modulator into a predetermined shape. The diffractive optical element 3 is configured by forming a step having a pitch of about the wavelength of the exposure light (illumination light) on the substrate, and has an action of diffracting the incident beam at a desired angle. That is, the diffractive optical element 3 is a spatial light modulator that spatially modulates and emits incident light.

Specifically, a diffractive optical element for circular illumination (for ring-shaped illumination, for multi-pole illumination, etc.) is placed in the far field (or Fraunhofer diffraction region) when, for example, a parallel light flux having a rectangular cross section is incident. It has the function of forming a circular (ring band, multiple poles, etc.) light intensity distribution. As an example, the diffractive optical element 3 is a diffractive optical element for circular illumination, and is installed interchangeably with a diffractive optical element for annular illumination, a diffractive optical element for multipole illumination, and the like.

The light that has passed through the diffractive optical element 3 is condensed by the relay optical system 4 and then incident on the micro fly-eye lens (or fly-eye lens) 5. The front focal position of the relay optical system 4 is located near the diffractive optical element 3, and the posterior focal position of the relay optical system 4 is located on the incident side surface of the microfly eye lens 5. That is, the relay optical system 4 optically positions the diffractive optical element 3 and the surface of the microfly-eye lens 5 on the incident side in a Fourier transform relationship.

As shown in FIG. 3, the light passing through the diffractive optical element 3 for circular illumination has a circular light intensity distribution (terrestrial field) centered on the optical axis AX of the illumination optical system, and is incident on the microfly eye lens 5. Form on the side surface. A shift portion 6 is provided between the diffractive optical element 3 and the relay optical system 4 to translate the incident light in a desired direction by a desired distance and emit it. The specific configuration and action of the shift unit 6 will be described later.

A microfly-eye lens is an optical element composed of a large number of microlenses having a large number of positive refractive powers arranged two-dimensionally, and is configured by etching a parallel flat plate to form a microlens group. .. In a micro fly-eye lens, unlike a fly-eye lens composed of lens elements isolated from each other, a large number of micro lenses are integrally formed without being isolated from each other. However, the micro fly-eye lens is the same wave surface split type optical integrator as the fly-eye lens in that the lenslets (lens elements) are arranged vertically and horizontally.

Specifically, as shown in FIG. 3, the micro fly-eye lens 5 is provided with a large number of lenslets (wave surface dividing elements) 5a having a rectangular cross section arranged in parallel, so that the microfly eye lens 5 can be further described vertically and horizontally. It is composed of densely arranged arrangements. However, FIGS. 1 and 3 show an example in which the micro fly-eye lens 5 is configured with far fewer lenslets 5a than in reality for the sake of simplicity of illustration and description. As the micro fly eye lens 5, for example, a cylindrical micro fly eye lens can also be used. The construction and action of the cylindrical microfly eye lens is disclosed, for example, in US Pat. No. 6,913,373.

The luminous flux incident on the micro fly-eye lens 5 is two-dimensionally divided by a large number of lenslets 5a, and one spot light (small light source) is formed in the vicinity of the injection surface of the lenslet 5a on which the light is incident. .. That is, the incident side is on the posterior focal plane of the microfly-eye lens 5 (the posterior focal position of the composite optical system of the refractive plane on the incident side and the refracting plane on the emission side of the lenslet 5a) or in the vicinity thereof. A secondary light source (substantial surface light source consisting of a large number of small light sources: pupil intensity distribution) having almost the same light intensity distribution as the light intensity distribution formed on the surface of the lens is formed.

The light from the secondary light source formed in the illumination pupil immediately after the micro fly-eye lens 5 illuminates the mask blind 8 via the condenser optical system 7. The front focal position of the condenser optical system 7 is located on the rear focal plane of the microfly eye lens 5, and the posterior focal position of the condenser optical system 7 is located on the surface of the mask blind 8. That is, the condenser optical system 7 optically positions the posterior focal plane of the microfly-eye lens 5 and the plane of the mask blind 8 in a Fourier transform relationship. As a result, the light from a large number of small light sources formed in the illumination pupil immediately after the micro fly-eye lens 5 illuminates the mask blind 8 in a superimposed manner via the condenser optical system 7.

The light that has passed through the rectangular opening (light transmitting portion) of the mask blind 8 as the illumination field diaphragm is used for forming a variable pattern via the optical path bending mirror MR2, the imaging optical system 9, and the optical path bending mirror MR3. The array planes (mirror array planes) of the plurality of mirror elements of the spatial optical modulator 10 of the above are illuminated in a superimposed manner. That is, the imaging optical system 9 forms an image of the rectangular opening of the mask blind 8 on the mirror array surface of the spatial light modulator 10. In this way, the illumination optical system (1 to 9) forms a rectangular illumination region on the mirror array surface (irradiated surface) of the spatial light modulator 10 by the pulsed light supplied from the light source unit LS.

As shown in FIG. 4, the spatial light modulator 10 has a plurality of mirror elements 10a two-dimensionally arranged along the irradiated surface (object surface of the projection optical system PL) of the illumination optical system (1 to 9). A drive unit 10c that individually controls and drives the postures (positions, tilts, etc.) of the plurality of mirror elements 10a via a board 10b that holds the plurality of mirror elements 10a and a cable (not shown) connected to the board 10b. And have. In the spatial light modulator 10, the postures of the plurality of mirror elements 10a are changed by the action of the drive unit 10c that operates based on the command from the control system CR, and each mirror element 10a has a predetermined direction (or position). Is set to.

As shown in FIG. 5, the spatial light modulator 10 includes a plurality of minute mirror elements 10a arranged two-dimensionally, and spatially modulates the incident pulsed light according to the incident position. It is variably applied and ejected. For simplicity of description and illustration, FIGS. 4 and 5 show a configuration example in which the spatial light modulator 10 includes 4 × 4 = 16 mirror elements 10a, but in reality it is far more than 16. Is provided with a large number of mirror elements 10a.

According to one example, as shown in FIG. 5, the spatial light modulator 10 has a large number of minute particles arranged regularly and two-dimensionally along one plane with a plane-like reflecting surface facing the upper surface. It is a movable multi-mirror including a mirror element 10a which is a reflective element. Each mirror element 10a is movable, and the inclination of the reflection surface, that is, the inclination angle and the inclination direction of the reflection surface are independently controlled by the action of the drive unit 10c that operates based on the control signal from the control system CR. Each mirror element 10a rotates continuously (or discretely) by a desired rotation angle with two directions parallel to the reflection surface and orthogonal to each other (X direction and Z direction) as rotation axes. Can be done. That is, it is possible to two-dimensionally control the inclination of the reflecting surface of each mirror element 10a.

Although FIG. 5 shows a mirror element 10a having a square outer shape, the outer shape of the mirror element 10a is not limited to a square shape. However, from the viewpoint of light utilization efficiency, the shape can be arranged so that the gap between the mirror elements 10a is reduced (the shape that can be packed closest). Further, from the viewpoint of light utilization efficiency, the distance between two adjacent mirror elements 10a can be minimized.

In the first embodiment, as the spatial light modulator (pattern forming unit) 10 for variable pattern formation, the orientations of a plurality of mirror elements arranged two-dimensionally and having a planar reflecting surface are continuously or discretely oriented. Spatial light modulators that change each can be used. In this case, the plurality of mirror elements each have a planar reflective surface that can be tilted around at least one axis. As such a tilt mirror type spatial light modulator, for example, the spatial light modulator disclosed in US Pat. Nos. 6,522,454 and 7,405,862 can be used.

Further, as the spatial light modulator 10 for forming a variable pattern, for example, spatial light capable of individually controlling the height (position) of the reflecting surfaces of a plurality of mirror elements arranged two-dimensionally and having a planar reflecting surface. A modulator can also be used. In this case, the plurality of mirror elements each have a planar reflecting surface that moves so as to change the position of the light incident on the spatial light modulator in the traveling direction. Such piston-type spatial light modulators include, for example, spatial light modulation disclosed in US Pat. Nos. 5,312,513 and 7,206,117 and US Patent Publication No. 2013/0278912. A vessel can be used.

Further, as the spatial light modulator 10 for forming a variable pattern, a spatial light modulator that continuously or discretely changes the orientation of a plurality of mirror elements arranged two-dimensionally and having a stepped reflecting surface is used. You can also do it. In this case, the plurality of mirror elements can be tilted around at least one axis and each has a stepped reflecting surface. As such a phase step tilt mirror type spatial light modulator, for example, the spatial light modulator disclosed in US Pat. No. 7,110,159 can be used. Further, as the spatial light modulator for forming a variable pattern, a transmissive spatial light modulator having a plurality of transmissive optical elements arranged two-dimensionally and individually controlled can also be used.

In the spatial light modulator 10, the postures of the plurality of mirror elements 10a change according to the control signals (drive data of the plurality of mirror elements 10a) from the control system CR, and each mirror element 10a has a predetermined orientation (or each). Position) is set. The projection optical system PL includes a plurality of projection optical systems PL in a unit exposure region of a wafer (photosensitive substrate) W coated with a photoresist by reflected light from the spatial light modulator 10 illuminated by the illumination optical system (1 to 9). A predetermined pattern image corresponding to the mirror pattern formed by the mirror element 10a (tilt pattern, uneven pattern, etc. of the plurality of mirror elements 10a) is projected.

The wafer W is held on the wafer stage WS substantially parallel to the XZ plane. The wafer stage WS has a mechanism for moving the wafer stage WS (and thus the wafer W) in the X direction, the Y direction, the Z direction, the rotation direction around the X axis, the rotation direction around the Y axis, and the rotation direction around the Z axis. It has been incorporated. In the step-and-repeat method, a predetermined pattern corresponding to the mirror pattern of the spatial light modulator 8, for example, a device pattern, is set in one unit exposure area of a plurality of unit exposure areas set vertically and horizontally on the wafer W. Are exposed all at once. After that, the control system CR positions another unit exposure region of the wafer W with respect to the projection optical system PL by stepping the wafer stage WS along the XZ plane. In this way, the operation of batch-exposing the device pattern corresponding to the mirror pattern of the spatial light modulator 10 to the unit exposure region of the wafer W is repeated.

In the step-and-scan method, the control system CR moves the mirror pattern of the spatial light modulator 10 and the wafer stage WS in, for example, the Z direction according to the projection magnification of the projection optical system PL, and the spatial light modulator 10 The device pattern corresponding to the mirror pattern of the above is scanned and exposed on one unit exposure area of the wafer W. After that, the control system CR positions another unit exposure region of the wafer W with respect to the projection optical system PL by stepping the wafer stage WS along the XZ plane. In this way, the operation of scanning and exposing the device pattern corresponding to the mirror pattern of the spatial light modulator 10 to the unit exposure region of the wafer W is repeated.

The exposure apparatus of the first embodiment includes a control system CR that controls the shift unit 6 and the spatial light modulator 10 and comprehensively controls the operation of the exposure apparatus. In the first embodiment, the mirror arrangement surface (and thus the wafer) of the spatial light modulator 10 arranged on the illuminated surface of the illumination optical system (1 to 9) using the secondary light source formed by the microfly eye lens 5 as the light source. The exposed surface of W) is illuminated by Koehler illumination. When the number of wave plane divisions by the micro fly eye lens 5 is relatively large, it is formed in the global light intensity distribution formed on the incident side surface of the micro fly eye lens 5 and in the illumination pupil immediately after the micro fly eye lens 5. It shows a high correlation with the global light intensity distribution (pupil intensity distribution) of the entire secondary light source.

In the exposure apparatus of the first embodiment, the device pattern corresponding to the mirror pattern variably formed by the spatial optical modulator 10 according to the command from the control system CR is collectively exposed to the wafer W via the projection optical system PL. Alternatively, scan exposure (scan exposure) is performed. A device pattern corresponding to a mirror pattern variably formed by a spatial optical modulator having a plurality of mirror elements (optical elements) arranged two-dimensionally and individually controlled is exposed on a substrate via a projection optical system. For details of the maskless type exposure apparatus, US Pat. No. 8,792,081B2 and the like can be referred to.

In the first embodiment, since pulsed light having high coherence is supplied from the light source unit LS, the mirror array surface (illumination) of the spatial light modulator 10 is caused by interference between the lenslets 5a of the microfly eye lens 5. As shown in the figure on the left side of FIG. 6, one pulsed light tends to randomly form a non-uniform illuminance distribution on the irradiated surface of the optical system (1 to 9). In this case, in the conventional method of randomly superimposing non-uniform illuminance distributions, it is necessary to use a large number of pulsed lights to average the integrated illuminance distributions, as shown in the figure on the right side of FIG.

Specifically, in the conventional method, there is a relationship as shown in the following equation (1) between the contrast (speckle contrast) C of the illuminance distribution and the integrated number N of the pulsed light. By the way, for contrast C, when the average value of light intensity in the illuminance distribution is A, the square root of the variance σ ² of the light intensity from the average value A in the illuminance distribution, that is, the standard deviation σ is used, and the following equation ( It is defined as shown in 2).

With reference to equation (1), the contrast C of the illuminance distribution is proportional to the reciprocal of the square root of the integrated number N of the pulsed light, so a large number of pulsed lights are used to reduce the contrast C and average the integrated illuminance distribution. It is easy to understand the need.

In the first embodiment, in order to form an illuminance distribution having periods in the X and Z directions on the illuminated surface of the illumination optical system (1 to 9), that is, on the mirror array surface of the spatial light modulator 10. Along the lengths S1 and Y directions (corresponding to the Z direction on the mirror arrangement surface of the spatial light modulator 10) along the X direction of the region where light is emitted from the diffractive optical element 3 as the spatial light modulator. The length S2 is set. The light emitting region from the diffractive optical element 3 is, for example, limited by the action of the beam light transmitting unit 2 that guides a light flux having a cross section having a desired size and shape to the diffractive optical element 3. That is, the beam light transmitting unit 2 is arranged on the light source side of the diffractive optical element 3 and constitutes an irradiation area setting unit that sets a region on which the light from the light source LS is irradiated on the diffractive optical element 3.

Specifically, the length S1 along the X direction and the length S2 along the Y direction are set so as to satisfy the conditions represented by the following equations (3) and (4). In equations (3) and (4), f is the focal length of the relay optical system (strictly speaking, the optical system arranged between the diffractive optical element 3 and the microfly eye lens 5) 4, and λ is the pulsed light. P1 is the pitch along the X direction of the lenslet (wave plane dividing element) 5a of the microfly-eye lens 5, and P2 is the pitch along the Y direction of the lenslet 5a.
S1 ≦ 2 × (f × λ) / P1 (3)
S2 ≦ 2 × (f × λ) / P2 (4)

By limiting the light emission region from the diffractive optical element 3 so as to satisfy the equations (3) and (4), as shown in the figure on the left side of FIG. 7, the light intensity is substantially periodiced by one pulsed light. It is possible to obtain an illuminance distribution that changes in a target manner. Then, by superimposing the substantially periodic illuminance distribution while shifting the position according to the movement width according to the period, as shown in the figure on the right side of FIG. 7, the pulsed light (small integrated number) is smaller than that of the conventional method. Therefore, the integrated illuminance distribution on the irradiated surface can be made uniform. The length S1 along the X direction and the length S2 along the Y direction can also be referred to as a dimension S1 along the X direction and a dimension S2 along the Y direction.

Hereinafter, with reference to FIGS. 8 to 10, the method of the embodiment in which the periodic illuminance distributions are overlapped while being displaced according to the movement width according to the period will be described. However, in the following description, in order to facilitate understanding of the action and effect of the method of the embodiment, it is assumed that an illuminance distribution in which the light intensity changes periodically by one pulsed light can be obtained. FIG. 8 is a view in which the optical path between the diffractive optical element 3 and the surface 8a of the mask blind 8 is linearly developed along the optical axis AX. The x-coordinate, y-coordinate, and z-coordinate in the local coordinate system of FIG. 8 correspond to the X-coordinate, Y-coordinate, and Z-coordinate in the overall coordinate system of FIG.

In the first embodiment, as shown in FIG. 8, high coherence pulsed light supplied from the light source unit LS is transmitted through the diffractive optical element 3, the shift unit 6, and the relay optical system 4 to the microfly eye lens 5. It is incident on a plurality of lenslets 5a. The light divided by the plurality of lenslets 5a of the microfly-eye lens 5 forms a small light source composed of one spot light in the vicinity of the emission surface of the plurality of lenslets 5a on which the light is incident.

Light from the plurality of small light sources is superimposed on the surface 8a of the mask blind 8 via the condenser optical system 7. The mask blind surface 8a is optically conjugate with the illuminated surface of the illumination optical system (1 to 9) (the mirror array surface of the spatial light modulator 10 fixedly installed), and is formed on the surface 8a of the mask blind 8. The illuminance distribution to be performed may match the illuminance distribution formed on the irradiated surface.

In the first embodiment, since the length S2 of the light emitting region from the diffractive optical element 3 in the Y direction is limited by the equation (4), as shown in FIG. 9, one pulsed light is used in the y direction. The first illuminance distribution 41a whose light intensity changes periodically is formed on the mask blind surface 8a which is optically coupled to the irradiated surface. The y-direction pitch (period) Py of the first illuminance distribution 41a is calculated by the following equation, where Sy is the y-direction size of the lenslet 5a, λ is the central wavelength of light, and f2 is the focal length of the condenser optical system 7. It is represented by 5).
Py = (λ × f2) / Sy (5)

In the following description, for ease of understanding, it is assumed that light is incident on a total of nine lenslets 5a in which three rows are arranged in the x direction and three rows are arranged in the y direction. In this case, the first illuminance distribution 41a, the second illuminance distribution 41b in which the first illuminance distribution 41a is moved by Py / 3 in the + y direction, and the second illuminance distribution 41b in which the second illuminance distribution 41b is moved by Py / 3 in the + y direction. By superimposing the three illuminance distributions 41c, a substantially uniform distribution of light intensity along the y direction, that is, a substantially uniform integrated illuminance distribution 41d along the y direction can be obtained.

In other words, by superimposing the three illuminance distributions 41a, 41b and 41c displaced by Py / 3 from each other along the y direction, that is, the three illuminance distributions 41a, 41b and 41c having different phases in the y direction. By superimposing the above, a substantially uniform integrated illuminance distribution 41d can be obtained along the y direction. Generally, when the number of lenslets 5a in which light is incident in the y direction is Ny, the mask blind surface is formed by superimposing Ny illuminance distributions that are displaced from each other by Δr = Py / Ny along the y direction. A substantially uniform integrated illuminance distribution can be obtained along the y direction on the irradiated surface (mirror array surface of the spatial light modulator 10) of the illumination optical system (1 to 9) by 8a.

Specifically, in order to form the second illuminance distribution 41b in which the first illuminance distribution 41a is moved in the + y direction by Δr = Py / Ny (Ny = 3 in FIG. 8), the diffraction optical element 3 and the relay optical system 4 are formed. By the action of the shift portion 6 provided between the two, the incident light may be translated by Δu in the −y direction and emitted. As shown in FIG. 10, the shift unit 6 includes a pair of parallel plane plates 6a and 6b obliquely arranged with respect to the optical axis AX of the illumination optical system, and parallel plane plates 6a and 6b according to a command from the control system CR. Each has a drive unit 6c for rotationally driving.

The parallel flat plate 6a is configured to be rotatable around the axis 6aa parallel to the optical axis AX, and the parallel flat plate 6b is configured to be rotatable around the axis 6ba parallel to the optical axis AX. The shift unit 6 has a function of rotating and driving the parallel flat plates 6a and 6b in accordance with a command from the control system CR to translate the incident light in a desired direction by a desired distance and emit the light. ..

The required parallel transport distance Δu by the shift unit 6 is expressed by the following equation (6), where f is the focal length of the relay optical system 4. At this time, due to the action of the shift portion 6, the light incident on the mask blind surface 8a moves in the + y direction by Δr = Py / Ny, and the position of the second illuminance distribution 41b formed on the mask blind surface 8a is the first position. It moves by Py / Ny (Ny = 3 in FIG. 8) in the + y direction from the formation position of the illuminance distribution 41a.
Δu = (λ × f) / (Sy × Ny) (6)

In this way, the first illuminance distribution 41a was formed by one (or a plurality) of pulsed lights, and the next one (or a plurality) of pulsed lights moved from the first illuminance distribution 41a in the + y direction by Py / Ny. By forming a second illuminance distribution 41b at a position and forming a third illuminance distribution 41c at a position moved by Py / Ny in the + y direction from the second illuminance distribution 41b by the next one (or a plurality) of pulsed lights. , A substantially uniform integrated illuminance distribution 41d can be obtained along the y direction. That is, the integrated illuminance distribution can be made uniform by superimposing one (or a plurality) of the three illuminance distributions 41a, 41b, and 41c that are displaced from each other by Py / Ny in the + y direction. Here, changing the formation position of the illuminance distribution in the y direction on the irradiated surface means that the origin of the function indicating the state of change in the illuminance (or light intensity) along the y direction on the irradiated surface is in the y direction. It can be said that it is changing.

In other words, Ny reference points are set at intervals of Py / Ny along the y direction, and each illuminance so that the center point along the y direction of each illuminance distribution coincides with the Ny reference points. By changing the formation position of the distribution, the integrated illuminance distribution can be made uniform. At this time, the order of the reference points at which the center points along the y direction of each illuminance distribution should match is arbitrary, and the number of times the center points along the y direction of each illuminance distribution are matched with the corresponding reference points is also the same. If it is, it is optional. That is, the order of forming the first illuminance distribution 41a, the second illuminance distribution 41b, and the third illuminance distribution 41c is arbitrary, and the number of times each illuminance distribution is formed is also arbitrary.

Similarly, although not shown, the length S1 of the light emitting region from the diffractive optical element 3 in the X direction is limited by the equation (3), so that one pulsed light can be used not only in the y direction but also in the x direction. An illuminance distribution in which the light intensity changes periodically is also formed in the direction. The x-direction pitch (period) Px of the illuminance distribution is expressed by the following equation (7), where the x-direction size of the lenslet 5a is Sx. Further, the required parallel movement distance Δu'by the shift unit 6 is expressed by the following equation (8).
Px = (λ × f2) / Sx (7)
Δu'= (λ × f) / (Sx × Nx) (8)

By superimposing three illuminance distributions that are displaced by Px / 3 from each other along the x direction, a substantially uniform integrated illuminance distribution can be obtained along the x direction. Generally, when the number of lenslets 5a in which light is incident is Nx, the mask blind surface 8a, by superimposing Nx illuminance distributions that are displaced by Px / Nx from each other along the x direction, As a result, a substantially uniform integrated illuminance distribution can be obtained along the x direction on the irradiated surface (mirror array surface of the spatial light modulator 10) of the illumination optical system (1 to 9).

In order to obtain a nearly uniform integrated illuminance distribution along the x and y directions on the irradiated surface, they were displaced by Px / Nx from each other along the x direction and by Py / Ny from each other along the y direction. A total of (Nx × Ny) illuminance distributions may be superimposed. In other words, using (Nx × Ny) (or an integral multiple of it) pulsed light, they were displaced by Px / Nx from each other along the x direction and by Py / Ny from each other along the y direction. By forming a total (Nx × Ny) (or an integral multiple thereof) illuminance distribution, a substantially uniform integrated illuminance distribution can be obtained along the x-direction and the y-direction on the irradiated surface.

The order of forming (Nx × Ny) illuminance distributions (or an integral multiple thereof) can be arbitrarily set, and the number of times the illuminance distributions are formed at one position is arbitrary as long as they are the same. In FIG. 8, since it is assumed that light is incident on a total of nine lenslets 5a in which three rows are arranged in the x direction and three rows are arranged in the y direction, light is incident on (Nx × Ny). This means the number Np of the lenslets 5a to be used.

FIG. 11 is a diagram comparing a conventional method of randomly superimposing non-uniform illuminance distributions and a method of an embodiment in which periodic illuminance distributions are superposed while being displaced according to a movement width according to a period. is there. In FIG. 11, the horizontal axis represents the integrated number N, and the vertical axis represents the contrast C of the integrated illuminance distribution in a logarithmic manner. Reference numeral 51 indicates the relationship between the integrated number N and the contrast C according to the conventional method, and reference numeral 52 indicates the relationship between the integrated number N and the contrast C according to the method of the embodiment.

Referring to FIG. 11, the integrated number N required to suppress the contrast C of the integrated illuminance distribution to 0.1, that is, 10% is about 20 in the method of the embodiment, but far more than 60 in the conventional method. The value exceeds, for example, about 100. According to another viewpoint, when the integrated number N of the illuminance distribution formed by one pulsed light is about 30, the contrast C of the integrated illuminance distribution can be reduced to about 7% by the method of the embodiment. With the conventional method, it can be reduced only to about 19%.

FIG. 12 is a diagram showing the relationship between the length of the light emitting region from the diffractive optical element and the contrast of the integrated illuminance distribution when the integrated number N = 32 in the embodiment. In FIG. 12, the horizontal axis represents the lengths S1 and S2 (units: (f × λ) / P1, (f × λ) / P2) of the light emitting region from the diffractive optical element 3, and the vertical axis represents the integrated illuminance. The contrast C of the distribution is shown. Reference numeral 53 indicates the relationship between the lengths S1 and S2 and the contrast C in the embodiment, and the linear broken line 54 extending in the horizontal direction is obtained by the conventional method when the integration number N = 32 in FIG. It corresponds to the value of contrast C, that is, C≈0.17.

With reference to FIG. 12, for example, when the integrated number N = 32, it can be seen that if the equations (3) and (4) are satisfied, the effect of reducing the contrast C by the method of the embodiment becomes larger than that of the conventional method. Further, in order to further enhance the effect of reducing the contrast C by the method of the embodiment, the length of the light emitting region from the diffractive optical element 3 as the spatial light modulator along the X direction and the length along the Y direction. It can be seen that S2 may be restricted so as to satisfy the conditions represented by the following equations (9) and (10).
S1 ≦ 1.5 × (f × λ) / P1 (9)
S2 ≦ 1.5 × (f × λ) / P2 (10)

As described above, in the first embodiment, the length S1 along the X direction and the length S2 along the Y direction of the light emitting region from the diffractive optical element 3 are limited by the action of the beam light transmitting unit 2. are doing. As a result, one pulsed light forms an illuminance distribution on the surface 8a of the mask blind 8 whose light intensity changes substantially periodically along the x and y directions, and thus the light intensity changes in the X and Z directions. An illuminance distribution that changes substantially periodically along the line can be formed on the irradiated surface (mirror array surface of the spatial light modulator 10 fixedly installed) of the illumination optical system (1 to 9).

In this case, the illuminated surface of the illumination optical system (1 to 9) is changed by the shift portion 6 changing the formation position of the illuminance distribution according to the movement width corresponding to the x-direction period Px and the y-direction period Py of the illuminance distribution. A substantially uniform integrated illuminance distribution can be obtained along the X and Z directions in (the mirror array surface of the spatial optical modulator 10). In other words, by using Np (or an integral multiple of) pulsed light to form illuminance distributions at different Np positions and superimposing them, a nearly uniform integrated illuminance distribution can be obtained on the irradiated surface. Can be done.

In this way, in the illumination optical system (1 to 9) according to the first embodiment, the integrated illuminance distribution on the mirror array surface (irradiated surface) of the spatial light modulator 10 can be made uniform by using a relatively small amount of pulsed light. it can. Further, in the exposure apparatus according to the first embodiment, the wafer (substrate) W is exposed to light by using the illumination optical system (1 to 9) that equalizes the integrated illuminance distribution on the mirror array surface of the spatial light modulator 10. The uniformity of the pattern line width can be improved, and thus a good device can be manufactured.

FIG. 13 is a diagram schematically showing the configuration of the exposure apparatus according to the second embodiment. The second embodiment has a configuration similar to that of the first embodiment, but the pupil intensity distribution is variable instead of the diffractive optical element 3 that fixedly forms the pupil intensity distribution in the illumination pupil immediately after the microfly eye lens 5. It is different from the first embodiment in that the spatial light modulator 23 to be formed is arranged. In FIG. 13, the elements having the same functions as the components in the first embodiment of FIG. 1 are designated by the same reference numerals as those in FIG. Hereinafter, the configuration and operation of the second embodiment will be described with a focus on the differences from the first embodiment.

In the second embodiment, the high-coherence pulsed light supplied from the light source unit LS enters the spatial light modulator 23 via the delay optical system 1 and the beam light transmitting unit 2. The spatial light modulator 23 has the same configuration as the spatial light modulator 10 for forming a variable pattern. That is, as shown in FIG. 14, the spatial light modulator 23 includes a plurality of mirror elements 23a arranged in a predetermined plane, a base 23b holding the plurality of mirror elements 23a, and a cable connected to the base 23b. It includes a drive unit 23c that individually controls and drives the postures of the plurality of mirror elements 23a via (not shown).

The beam light transmitting unit 2 guides the light beam incident through the light source unit LS and the delayed optical system 1 to the spatial light modulator 23 while converting it into a luminous flux having a cross section of an appropriate size and shape, and at the same time, the spatial light modulator 23. Actively corrects positional fluctuations and angular fluctuations of light incident on the array planes (mirror array planes) of the plurality of mirror elements 23a. In the spatial light modulator 23, the postures of the plurality of mirror elements 23a are changed by the action of the drive unit 23c that operates based on the command from the control system CR, and each mirror element 23a is set to a predetermined direction. ..

The spatial light modulator 23 includes a plurality of minute mirror elements 23a arranged in two dimensions, and emits incident light by variably applying spatial modulation according to the incident position. .. For simplicity of description and illustration, FIGS. 14 and 5 show a configuration example in which the spatial light modulator 23 includes 4 × 4 = 16 mirror elements 23a, but in reality far more than 16. A large number, typically about 4000 to 100,000 mirror elements 23a are provided.

In the spatial optical modulator 23, in a reference state in which the reflecting surfaces of all the mirror elements 23a are set along one plane, the optical axis AX of the optical path between the beam light transmitting unit 2 and the spatial optical modulator 23 Light rays incident along the parallel direction are reflected by the spatial light modulator 23 and then travel in a direction parallel to the optical axis AX of the optical path between the spatial optical modulator 23 and the relay optical system 4. Has been done. Further, as described above, the mirror array surface of the spatial light modulator 23 and the surface 5b on the incident side of the microfly eye lens 5 are optically positioned in a Fourier transform relationship via the relay optical system 4. ..

Therefore, the light reflected by the plurality of mirror elements 23a of the spatial light modulator 23 and given a predetermined angular distribution forms a predetermined light intensity distribution on the incident side surface 5b of the microfly eye lens 5. That is, in the relay optical system 4, the angle at which the plurality of mirror elements 23a of the spatial light modulator 23 gives to the emitted light is incident on the microfly eye lens 5 which is the far field (Fraunhofer diffraction region) of the spatial light modulator 23. Convert to a position on the side surface 5b. In this way, the light intensity distribution (pupil intensity distribution) of the secondary light source formed by the microfly-eye lens 5 is the light formed by the spatial light modulator 23 and the relay optical system 4 on the incident side surface 5b of the microfly-eye lens 5. The distribution corresponds to the intensity distribution.

As shown in FIG. 5, the spatial optical modulator 23 is a large number of minute reflecting elements regularly and two-dimensionally arranged along one plane with the plane reflecting surface facing the upper surface. It is a movable multi-mirror including a mirror element 23a. Each mirror element 23a is movable, and the inclination of the reflection surface, that is, the inclination angle and the inclination direction of the reflection surface are independently controlled by the action of the drive unit 23c that operates based on the control signal from the control system CR. Each mirror element 23a can rotate continuously (or discretely) by a desired rotation angle with the two directions parallel to the reflecting surface and orthogonal to each other as rotation axes. That is, it is possible to two-dimensionally control the inclination of the reflecting surface of each mirror element 23a.

Although FIG. 5 shows a mirror element 23a having a square outer shape, the outer shape of the mirror element 23a is not limited to a square shape. However, from the viewpoint of light utilization efficiency, the shape can be arranged so that the gap between the mirror elements 23a is reduced (the shape that can be packed closest). Further, from the viewpoint of light utilization efficiency, the distance between two adjacent mirror elements 23a can be minimized.

In the spatial light modulator 23, the postures of the plurality of mirror elements 23a are changed by the action of the drive unit 23c that operates in response to the control signal from the control system CR, and each mirror element 23a is set to a predetermined direction. To. The light reflected by the plurality of mirror elements 23a of the spatial light modulator 23 at a predetermined angle forms a desired pupil intensity distribution in the illumination pupil immediately after the microfly eye lens 5. As described above, the spatial light modulator 23 is a spatial light modulator that spatially modulates and emits incident light, and variably forms a pupil intensity distribution in the illumination pupil immediately after the microfly eye lens 5. ..

In the second embodiment, as an example, a tilt mirror type spatial light modulator 23 is used to variably form a pupil intensity distribution in the illumination pupil immediately after the microfly eye lens 5. However, without being limited to this, a piston type spatial light modulator, a phase step tilt mirror type spatial light modulator, or a transmission type spatial light modulator is used to variably form the pupil intensity distribution. You may.

In the second embodiment, as shown in FIG. 3, a spatial light modulator 23 is used to obtain a circular light intensity distribution (illumination field) centered on the optical axis AX on the incident side surface of the microfly eye lens 5. It is possible to form a circular pupil intensity distribution in the illumination pupil immediately after the microfly eye lens 5. Further, although not shown, the spatial light modulator 23 is used to form a ring-shaped pupil intensity distribution in the illumination pupil immediately after the microfly eye lens 5, or a pupil intensity distribution having a desired shape such as a plurality of poles. Can be formed.

In the first embodiment, the light emitting region of the light from the diffractive optical element 3 as the spatial light modulator is limited by the action of the beam light transmitting unit 2. However, in the second embodiment, the light emitted from the mirror element 23a in the predetermined region on the spatial light modulator 23 is incident on the relay optical system 4, and the light emitted from the mirror element 23a outside the predetermined region is emitted. By controlling the drive unit 23c so that it does not enter the relay optical system 4, the light emission region from the spatial light modulator 23 can be limited.

In this way, also in the illumination optical system (1 to 9) of the second embodiment, as in the case of the first embodiment, a relatively small amount of pulsed light is used on the mirror array surface (illuminated surface) of the spatial light modulator 10. The integrated illuminance distribution can be made uniform. Further, by using the illumination optical system (1 to 9) that equalizes the integrated illuminance distribution on the mirror array surface of the spatial optical modulator 10, the uniformity of the pattern line width exposed on the wafer (substrate) W is improved. And thus a good device can be manufactured.

In the above-described embodiment, the shift unit 6 arranged in the optical path between the diffractive optical element 3 or the spatial light modulator 23 and the relay optical system 4 has an illuminance distribution according to the movement width according to the period of the illuminance distribution. It constitutes a relative position change part that moves the formation position. In other words, the shift unit 6 as the relative position change unit has the spatial light modulator 10 as a fixedly installed pattern forming unit and the illuminance distribution for each irradiation of one or more pulsed lights. Change the relative position of.

In the above-described embodiment, the shift unit 6 is arranged in the optical path between the diffraction optical element 3 or the spatial light modulator 23 and the relay optical system 4. However, without being limited to this, for example, a shift portion as a relative position changing portion can be arranged in the optical path between the condenser optical system 7 and the mask blind 8 (or the spatial light modulator 10).

Further, as the relative position changing portion, as shown in FIG. 15, it is also possible to use the tilt portion 15 arranged in the optical path between the micro fly-eye lens 5 and the condenser optical system 7. The tilt unit 15 includes a polygon mirror 15a that rotates around an axis line 15aa extending in the X direction, and a drive unit 15b that rotationally drives the polygon mirror 15a according to a command from the control system CR. The tilt unit 15 has a function of deflecting and emitting light incident along the optical axis AX by a variable angle, for example.

The tilt portion 15 as the relative position changing portion may be arranged in the optical path between the relay optical system 4 and the micro fly-eye lens 5, for example. Further, a galvano mirror, a vibration mirror, or the like can be used as a tilt portion that deflects the incident light by a variable angle and emits it.

FIG. 16 is a diagram schematically showing the internal configuration of the shift portion according to the modified example. Referring to FIG. 16, the shift portion 6A according to the modified example is oblique along the optical axis AX in the optical path between the diffractive optical element 3 (or the spatial optical modulator 23) and the relay optical system 4. A pair of mirrors 61a and 61b provided, an fθ lens 62, a polygon mirror 63 that rotates around an axis 63a extending in the X direction, and a drive unit 63b that rotationally drives the polygon mirror 63 according to a command from the control system CR. , And a motor 64.

The fθ lens 62 and the polygon mirror 63 are arranged along the optical axis AX1 extending in the Y direction, and are integrally held as one unit on, for example, a base plate (not shown). The motor 64 rotates a unit including the fθ lens 62 and the polygon mirror 63 integrally held around the optical axis AX1 in accordance with a command from the control system CR. In the shift unit 6A, the light from the diffractive optical element 3 (or the spatial light modulator 23) is reflected by the mirror 61a and incident on the polygon mirror 63 via the fθ lens 62.

The light reflected by the polygon mirror 63 enters the relay optical system 4 via the fθ lens 62 and the mirror 61b. In the shift unit 6A, the drive unit 63b rotates the polygon mirror 63 around the axis 63a according to a command from the control system CR, and the motor 64 rotates a unit including the fθ lens 62 and the polygon mirror 63 around the optical axis AX1. By driving, it has a function of translating the incident light in a desired direction by a desired distance and emitting the light.

In other words, the illuminance on the mirror array surface (illuminated surface; XZ plane) of the spatial optical modulator 10 depends on the rotation angle position around the optical axis AX1 of the unit composed of the fθ lens 62 and the polygon mirror 63. The moving direction of the distribution changes, and the moving distance of the illuminance distribution on the irradiated surface changes depending on the rotation angle position around the axis 63a of the polygon mirror 63. At this time, the divergence angle or the convergence angle of the light incident on the fθ lens 62 is equal to the divergence angle or the convergence angle of the light emitted from the fθ lens 62. That is, the divergent state or the convergent state of the light emitted from the unit including the fθ lens 62 and the polygon mirror 63 is such that the divergent state or the convergent state of the light incident on the unit is maintained. An image rotator (for example, an image rotation prism) may be used in order to change the moving direction of the illuminance distribution on the mirror array surface (irradiated surface; XZ plane) of the spatial light modulator 10. In the above-described embodiment and modification, the shift units 6 and 6A are arranged in the optical path between the diffraction optical element 3 (or the spatial light modulator 23) and the relay optical system 4. However, without being limited to this, for example, a shift portion as a relative position changing portion can be arranged in the optical path between the condenser optical system 7 and the mask blind 8 (or the spatial light modulator 10).

In the above-described embodiment, the integrated illuminance distribution is made uniform by changing the formation position of the illuminance distribution on the mirror array surface of the spatial light modulator 10 which is fixedly installed. However, the present invention is not limited to this, and the formation position of the illuminance distribution may be fixedly set, and the spatial light modulator 10 as the pattern forming portion may be moved according to the movement width according to the period of the illuminance distribution. ..

In the above-described embodiment, the spatial light modulator 10 having a plurality of mirror elements (optical elements) 10a arranged two-dimensionally and individually controlled is used as the pattern forming unit. However, the present invention is not limited to this, and a mask (reticle) on which a pattern to be transferred is formed may be installed on the object surface of the projection optical system as a pattern forming portion.

In the above-described embodiment, attention is paid to the influence of interference between the lenslets 5a of the microfly-eye lens 5, but it is formed immediately after the lenslet 5a due to the interference inside one lenslet 5a. The diameter of the spot light may be large. In this case, the coherence inside the lenslet 5a may be lowered by appropriately changing the direction of the pulsed light emitted from the delayed optical system 1 for each pulse.

In the above-described embodiment, the formation position of the illuminance distribution whose light intensity changes periodically along a predetermined direction and the irradiated surface on the object are relatively moved in a predetermined direction according to the movement width according to the period. As a result, the integrated illuminance distribution is made uniform. However, the distribution is not limited to the illuminance distribution in which the light intensity changes periodically, and the formation position of the illuminance distribution in which the light intensity changes according to a certain property along a predetermined direction and the irradiated surface on the object are the distribution. It is also possible to make the integrated illuminance distribution uniform by relatively moving in a predetermined direction according to the movement width according to the property.

In other words, for each irradiation of one or more pulsed lights supplied from the light source, the relative position of the illuminance distribution whose light intensity changes along a predetermined direction and the irradiated surface on the object is set in a predetermined direction. By changing in, the integrated illuminance distribution can be made uniform. In other words, the first pulsed light forms a first illuminance distribution in which the light intensity changes along a predetermined direction on the irradiated surface on the object, and the second pulsed light covers the first illuminance distribution. By forming a second illuminance distribution that is a distribution that is relatively moved in a predetermined direction with respect to the irradiation surface, the integrated illuminance distribution can be made uniform.

In this case, the first illuminance distribution is formed, and after the relative movement is performed, the second illuminance distribution is formed. At least a part of the first illuminance distribution and at least a part of the second illuminance distribution have the same distribution characteristics. Then, by changing the relative positions of at least a part of the first illuminance distribution and at least a part of the second illuminance distribution in a predetermined direction, the integrated illuminance distribution can be made uniform.

The exposure apparatus of the above-described embodiment is manufactured by assembling various subsystems including each component listed in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Will be done. In order to ensure these various precisions, before and after this assembly, adjustments for achieving optical accuracy for various optical systems, adjustments for achieving mechanical accuracy for various mechanical systems, and various electrical systems Is adjusted to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connections between the various subsystems, wiring connections of electric circuits, piping connections of atmospheric pressure circuits, and the like. It goes without saying that there is an individual assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. After the process of assembling the various subsystems into the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracy of the exposure apparatus as a whole. The exposure apparatus may be manufactured in a clean room in which the temperature, cleanliness, and the like are controlled.

Next, a device manufacturing method using the exposure apparatus according to the above-described embodiment will be described. FIG. 17 is a flowchart showing a manufacturing process of a semiconductor device. As shown in FIG. 17, in the semiconductor device manufacturing process, a metal film is vapor-deposited on a wafer W serving as a substrate of the semiconductor device (step S40), and a photoresist, which is a photosensitive material, is applied onto the vapor-deposited metal film. (Step S42). Subsequently, using the projection exposure apparatus of the above-described embodiment, a predetermined pattern corresponding to the mirror pattern (or the pattern formed on the mask) of the spatial light modulator for forming a variable pattern is applied to each shot region on the wafer W. The transfer is performed (step S44: exposure step), and the wafer W on which the transfer is completed is developed, that is, the photoresist on which the pattern is transferred is developed (step S46: development step).

After that, using the resist pattern generated on the surface of the wafer W in step S46 as a mask, processing such as etching is performed on the surface of the wafer W (step S48: processing step). Here, the resist pattern is a photoresist layer in which irregularities having a shape corresponding to the pattern transferred by the projection exposure apparatus of the above-described embodiment are generated, and the recesses penetrate the photoresist layer. Is. In step S48, the surface of the wafer W is processed through this resist pattern. The processing performed in step S48 includes, for example, at least one of etching of the surface of the wafer W and film formation of a metal film or the like. In step S44, the projection exposure apparatus of the above-described embodiment transfers the pattern using the wafer W coated with the photoresist as a photosensitive substrate.

FIG. 18 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 18, in the liquid crystal device manufacturing process, a pattern forming step (step S50), a color filter forming step (step S52), a cell assembling step (step S54), and a module assembling step (step S56) are sequentially performed. In the pattern forming step of step S50, a predetermined pattern such as a circuit pattern and an electrode pattern is formed on a glass substrate coated with a photoresist as a plate P by using the projection exposure apparatus of the above-described embodiment. In this pattern forming step, an exposure step of transferring a pattern to a photoresist layer using the projection exposure apparatus of the above-described embodiment and development of a plate P on which the pattern is transferred, that is, development of a photoresist layer on a glass substrate A developing step of forming a photoresist layer having a shape corresponding to the pattern and a processing step of processing the surface of the glass substrate through the developed photoresist layer are included.

In the color filter forming step of step S52, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix, or three dots of R, G, and B are arranged. A color filter is formed by arranging a plurality of striped filter sets in the horizontal scanning direction. In the cell assembly step of step S54, a liquid crystal panel (liquid crystal cell) is assembled using the glass substrate on which the predetermined pattern is formed in step S50 and the color filter formed in step S52. Specifically, for example, a liquid crystal panel is formed by injecting liquid crystal between a glass substrate and a color filter. In the module assembly step of step S56, various parts such as an electric circuit and a backlight for performing the display operation of the liquid crystal panel are attached to the liquid crystal panel assembled in step S54.

Further, the present embodiment is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, a liquid crystal display element formed on a square glass plate or a sheet-shaped flexible body, a plasma display, or the like. It can be widely applied to an exposure apparatus for a display device of the above, and an exposure apparatus for manufacturing various devices such as an image pickup device (CCD or the like), a micromachine, a thin film magnetic head, and a DNA chip. Further, the present embodiment can also be applied to an exposure process (exposure apparatus) when a mask (photomask, reticle, etc.) on which a mask pattern of various devices is formed is manufactured by using a photolithography process.

In the above embodiment, a method of filling the optical path between the projection optical system and the photosensitive substrate with a medium having a refractive index larger than 1.1 (typically a liquid), a so-called immersion method, is applied. Is also good. In this case, for example, as disclosed in US Patent Application Publication No. 2007/2422747, a liquid (for example, pure water) that transmits illumination light IL between the optical member at the tip of the projection optical system PL and the wafer W. ) Is supplied and recovered by a local immersion device. In the case of the immersion type, the resolution can be further increased.

In the above-described embodiment, it is also possible to apply the so-called polarized illumination method disclosed in US Publication No. 2006/017901 and No. 2007/014667. Here, the teachings of US Patent Publication No. 2006/0170901 and US Patent Publication No. 2007/0146766 are incorporated as references. Further, in the above-described embodiment, as the light source unit LS, an ArF excimer laser light source that supplies pulsed light having a wavelength of 193 nm or a KrF excimer laser light source that supplies pulsed light having a wavelength of 248 nm can also be used. Further, in the above-described embodiment, the light source unit LS is not limited to the one that supplies pulsed light, and for example, a light source that supplies continuous light, for example, a CW (Continuous Wave) laser light source may be used.

It should be noted that the present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

1 Delay optical system 2 Beam transmitter 3 Diffractive optical element 4 Relay optical system 5 Micro fly-eye lens (optical integrator)
6 Shift 7 Condenser optical system 8 Mask blind 9 Imaging optical system 10 Spatial light modulator for variable pattern formation 23 Spatial light modulator for pupil intensity distribution formation LS Light source CR Control system PL Projection optical system W wafer WS wafer stage

Claims (24)

In an illumination optical system that illuminates the illuminated surface with light from a light source
A spatial light modulator that spatially modulates and emits light incident from the light source,
A relay optical system arranged in the optical path of light from the spatial light modulator,
An optical integrator having a plurality of wave plane dividing elements arranged in parallel in the optical path of light from the relay optical system, and
A condenser optical system that superimposes a plurality of light fluxes divided on the wave surface by the optical integrator on the irradiated surface is provided.
The length S1 along the first direction of the region for emitting light on the spatial light modulator has the focal length of the relay optical system as f, the central wavelength of the light as λ, and the plurality of wave plane dividing elements. When the pitch along the first direction is P1
S1 ≦ 2 × (f × λ) / P1
Meet the conditions,
In order to obtain a uniform integrated illuminance distribution along the first direction on the irradiated surface, according to the movement width of the illuminance distribution formed on the irradiated surface according to the period along the first direction. , to change along the forming position of the illumination distribution in the first direction, the illumination optical system. The length S1 is
S1 ≦ 1.5 × (f × λ) / P1
The illumination optical system according to claim 1, which satisfies the conditions of. The length S2 along the second direction orthogonal to the first direction of the region where the light is emitted is P2 when the pitch of the plurality of wave plane dividing elements along the second direction is P2.
S2 ≦ 2 × (f × λ) / P2
The illumination optical system according to claim 1 or 2, which satisfies the conditions of. The length S2 is
S2 ≦ 1.5 × (f × λ) / P2
The illumination optical system according to claim 3, which satisfies the conditions of. The illumination optical system according to any one of claims 1 to 4, wherein the spatial light modulator has a diffractive optical element. The illumination optical system according to any one of claims 1 to 4, wherein the spatial light modulator includes a spatial light modulator having a plurality of optical elements arranged two-dimensionally and individually controlled. .. The illumination optical system according to claim 6, wherein the spatial light modulator has a plurality of mirror elements arranged two-dimensionally and a drive unit for individually driving the postures of the plurality of mirror elements. Among the plurality of mirror elements, the light emitted from the mirror element in the region where the light is emitted on the spatial light modulator is incident on the relay optical system, and the light is incident on the spatial optical modulator. The illumination optical system according to claim 7, further comprising a control unit that controls the drive unit so that the light emitted from the mirror element outside the region where the light is emitted does not enter the relay optical system. Any one of claims 5 to 7, further comprising an irradiation area setting unit that is arranged on the light source side of the spatial light modulator and sets an area on which light from the light source is irradiated on the spatial light modulator. Illumination optics according to. The light source emits a plurality of pulsed lights,
The condenser optical system forms a first illuminance distribution in which the light intensity changes along a predetermined direction with the first pulsed light of the plurality of pulsed lights on the irradiated surface on the object, and the plurality of pulsed lights. The illumination optical system according to any one of claims 1 to 9, wherein a second illuminance distribution in which the light intensity changes along the predetermined direction with the second pulsed light is formed on the irradiated surface. The illumination according to claim 10, further comprising a relative position changing portion for changing the relative positions of at least a part of the first illuminance distribution and at least a part of the second illuminance distribution in the predetermined direction with respect to the object. Optical system. The illumination optical system according to claim 10 or 11, wherein the first and second illuminance distributions have a light intensity distribution that periodically changes in the predetermined direction. The illumination optical system according to claim 12, wherein the first illuminance distribution and the second illuminance distribution have different phases with respect to the predetermined direction. Any of claims 11 to 13, wherein the relative position changing portion has a tilt portion that is arranged in an optical path between the optical integrator and the condenser optical system and emits incident light by deflecting it by a variable angle. The illumination optical system according to item 1. The relative position changing portion has a shift portion which is arranged in an optical path between the condenser optical system and the irradiated surface and emits incident light by translating it by a variable distance. The illumination optical system according to any one item. Claims 11 to 15 include the relative position changing unit, which is arranged in an optical path between the spatial light modulator and the relay optical system and has a shift unit that translates and emits incident light by a variable amount. The illumination optical system according to any one of the above. Any of claims 11 to 15, wherein the relative position changing portion has a tilt portion that is arranged in an optical path between the relay optical system and the optical integrator and emits incident light by deflecting it by a variable angle. The illumination optical system according to item 1. The illumination optical system according to any one of claims 1 to 17, further comprising a generation unit that generates a plurality of pulsed lights temporally multiplexed from one pulsed light supplied from the light source. The generation unit guides a dividing member that divides one pulsed light supplied from the light source into two pulsed lights, and guides one pulsed light that has passed through the dividing member along the first optical path and passes through the dividing member. The illumination optical system according to claim 18, further comprising a light guide optical system that guides the other pulsed light along a second optical path longer than the first optical path. The 19th aspect of the present invention, wherein the generation unit emits the one pulsed light along the first path and the other pulsed light along the second path different from the first path. Illumination optics. An exposure apparatus comprising the illumination optical system according to any one of claims 1 to 20, which illuminates a pattern forming portion that forms a predetermined pattern, and exposes the predetermined pattern on a substrate. The exposure apparatus according to claim 21, wherein the pattern forming unit includes a spatial light modulator having a plurality of optical elements arranged two-dimensionally and individually controlled. 22. The exposure apparatus according to claim 22, wherein the spatial light modulator has a plurality of mirror elements arranged two-dimensionally and a drive unit for individually controlling and driving the postures of the plurality of mirror elements. Using the exposure apparatus according to any one of claims 21 to 23, the predetermined pattern is exposed to the substrate.
The substrate to which the predetermined pattern is transferred is developed, and a mask layer having a shape corresponding to the predetermined pattern is formed on the surface of the substrate.
A device manufacturing method comprising processing the surface of the substrate via the mask layer.

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