JP2013073977A - Spatial light modulator, optical device, and exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spatial light modulator ensuring high resolution by using electrowetting and capable of controlling the phase of light passing through each pixel, as required.SOLUTION: A spatial light modulator 28 for modulating the light incident to an array surface DP includes a cell 34 having a barrier 33a in the z direction traversing the array surface DP, liquids Lqa, Lqb received in the cell 34 and having refractive indices and dielectric constants different from each other, a transparent electrode 36 provided in the window of the cell 34, and a bottom face electrode 37 provided on the bottom face of the cell 34. The ratio of thickness of the liquids Lqa, Lqb in the cell 34 is controlled by a voltage applied to the transparent electrode 36 and the bottom face electrode 37.

Description

  The present invention relates to a spatial light modulator that modulates incident light, a method for manufacturing the spatial light modulator, an exposure technique using the spatial light modulator, and a device manufacturing technique using the exposure technique.

  For example, in a lithography process for manufacturing a device (electronic device or microdevice) such as a semiconductor element or a liquid crystal display element, a predetermined pattern is formed in a lump on a substrate such as a wafer or a glass plate via a projection optical system. An exposure type or scanning exposure type exposure apparatus or the like is used. As these exposure apparatuses, in order to suppress the increase in manufacturing cost by preparing a mask for each of a plurality of types of devices and for each of a plurality of layers of a substrate, and to manufacture each device efficiently, Instead, spatial light modulators with an array of micromirrors, each with a variable tilt angle or height by means of a hinge mechanism, are used to create a reflective variable light / dark pattern on the object plane of the projection optics. Alternatively, a so-called maskless type exposure apparatus that generates a phase pattern is known. Thus, in the method of adjusting the tilt angle of the micromirror using the hinge mechanism, the drive mechanism of the micromirror is complicated, and further, it is difficult to realize a transmission type modulator.

  Therefore, as a spatial light modulator that can be used for maskless exposure, so-called electrowetting is used to move a transparent liquid or an opaque liquid on the optical path of each pixel (each optical element). Has proposed a modulator capable of setting each pixel to a bright state or a dark state (see, for example, Patent Document 1). Electrowetting is a phenomenon in which a liquid moves in accordance with a change in the contact angle or surface energy of the liquid and / or an electrostatic force with respect to the liquid that accompanies a change in the potential of the surface in contact with the liquid (for example, non-wetting). Patent Document 1).

Special table 2007-515802

Frieder Mugele and Jean-Christophe Baret, “Electrowetting: from basics to applications,” Journal of Physics: Condensed Matter, 17 (2005) R705-R774 (UK)

  In a conventional spatial light modulator using electrowetting, since each pixel is divided only by an electrode, for example, it is difficult to accurately set a plurality of pixels in a row alternately in a bright state and a dark state. It was difficult to increase the resolution. Furthermore, it is difficult for a conventional spatial light modulator using electrowetting to control the phase of light passing through each pixel.

  In view of such circumstances, an aspect of the present invention is a spatial light modulator capable of obtaining a high resolution using electrowetting and controlling the phase of light passing through each pixel as necessary, and the space. An object of the present invention is to provide a technique using an optical modulator.

  According to the first aspect of the present invention, a first spatial light modulator that modulates light incident on the arrangement surface is provided. The first spatial light modulator includes a cell portion having a partition wall portion along a first direction that crosses the arrangement surface, and first and second refractive indexes and dielectric constants that are accommodated in the cell portion. A liquid electrode; a first electrode provided on at least a part of a window part into which light of the cell part is incident; and a second electrode provided on at least a part of a bottom surface and a side surface of the cell part. The ratio of the thicknesses of the first and second liquids in the cell part is controlled by the voltage applied to the first and second electrodes, and the optical path length of the light passing through the cell part is controlled. Is.

  Moreover, according to the 2nd aspect, the 2nd spatial light modulator which modulates the light which injects into an arrangement surface is provided. The second spatial light modulator includes a cell portion having a partition wall portion along a first direction that crosses the arrangement surface, and first and second light transmittances and dielectric constants that are accommodated in the cell portion and differ from each other. A liquid electrode; a first electrode provided on at least a part of a window part into which light of the cell part is incident; and a second electrode provided on at least a part of a bottom surface and a side surface of the cell part. The voltage applied to the first and second electrodes of the cell controls the ratio of the thicknesses of the first and second liquids in the cell unit to control the transmittance of light passing through the cell unit. Is.

According to the third aspect, the spatial light modulator of the present invention, the first optical system for irradiating illumination light to the cell portion of the spatial light modulator, and the light from the cell portion are guided to the object. An optical device comprising a second optical system is provided.
Moreover, according to the 4th aspect, the exposure apparatus which exposes a board | substrate with exposure light is provided. The exposure apparatus includes a spatial light modulator having a plurality of cell portions according to the present invention, an illumination optical system for irradiating the exposure light to an array of the plurality of cell portions of the spatial light modulator, and the plurality of cell portions. A projection optical system for guiding the light on the substrate and projecting the pattern onto the substrate, and the light passing through the plurality of cells of the spatial light modulator to control the pattern exposed on the substrate And a control device for controlling the phase.

  Moreover, according to the 5th aspect, the exposure apparatus which exposes a board | substrate through a mask with exposure light is provided. The exposure apparatus includes a spatial light modulator having a plurality of cell portions according to the present invention, and an illumination optical system that illuminates the mask with the exposure light via the spatial light modulator, and the illumination optical system that illuminates the mask And a control device for controlling the phase of light passing through the plurality of cell portions of the spatial light modulator in order to control the distribution of the incident angle of the exposure light.

  According to a sixth aspect, there is provided a device manufacturing method comprising: forming a pattern of a photosensitive layer on a substrate using the exposure apparatus of the present invention; and processing the substrate on which the pattern is formed. Is provided.

  According to the spatial light modulators of the first and second aspects, the first electrode and the second electrode provided in the cell portion can be applied to the second electrode and the first electrode based on the difference in dielectric constant depending on the voltage applied to the first electrode and the second electrode. The balance of the electrostatic force between the first liquid and the second liquid changes, and the ratio of the thicknesses of the first and second liquids in the cell portion can be controlled by the action of electrowetting. Therefore, when the refractive indexes of the first and second liquids are different, the optical path length of the light passing through the pixel (optical element) including the cell portion based on the difference in thickness and refractive index of the two liquids, As a result, the phase can be controlled. On the other hand, when the transmittance of the incident light of the first and second liquids is different, the light passing through the pixel (optical element) including the cell portion based on the difference in thickness and transmittance of the two liquids Can be controlled.

  Furthermore, since each pixel is partitioned by the partition wall, the influence of electrostatic force between the pixels and the flow of liquid between the pixels are suppressed, and high resolution can be obtained.

(A) is a figure which shows schematic structure of the spatial light modulator which concerns on 1st Embodiment, (B) is an expansion perspective view which shows a part of main-body part of the spatial light modulator. FIG. 2 is an enlarged perspective view showing one pixel of the spatial light modulator of FIG. 1B and a block diagram showing a control system. (A) is an enlarged sectional view showing two pixels of the spatial light modulator of FIG. 1 (A), and (B) is an enlarged sectional view showing a main body of the spatial light modulator during manufacture. It is an expanded perspective view which shows one pixel of the spatial light modulator which concerns on a 1st modification, and a block diagram which shows a control system. (A) is an enlarged sectional view showing a pixel in the first state according to the first modification, (B) is an enlarged sectional view showing a pixel in an intermediate state, and (C) shows a pixel in the second state. It is an expanded sectional view. It is an expansion perspective view which shows one pixel of the spatial light modulator which concerns on a 2nd modification. It is an expansion perspective view which shows one pixel of the spatial light modulator which concerns on a 3rd modification. (A) is an enlarged sectional view showing a pixel in the first state according to the third modification, (B) is an enlarged sectional view showing a pixel in an intermediate state, and (C) shows a pixel in the second state. It is an expanded sectional view. FIG. 10A is an enlarged perspective view showing one pixel of a spatial light modulator according to a fourth modification, and FIG. 9B is a perspective view showing a convex portion of a bottom electrode in FIG. It is an expansion perspective view which shows one pixel of the spatial light modulator which concerns on a 5th modification. It is an expansion perspective view which shows one pixel of the spatial light modulator which concerns on a 6th modification. It is a figure which shows schematic structure of the exposure apparatus which concerns on 2nd Embodiment. It is a figure which shows schematic structure of the modification of 2nd Embodiment. It is a flowchart which shows an example of the manufacturing process of an electronic device.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS. 1 (A) to 3 (B). FIG. 1A shows a schematic configuration of a spatial light modulator (SLM) 28 according to this embodiment, and FIG. 1B enlarges a part of the main body 30 of the spatial light modulator 28. And show. The spatial light modulator 28 of the present embodiment includes a main body 30 having a plurality of pixels 32 as optical elements arranged in a two-dimensional array, and illumination light IL that is incident on and reflected from the pixels 32. And a modulation control unit 48 that individually controls the phase of the light, and modulates light incident on each pixel 32 using electrowetting (electrowetting). Illumination light IL is, for example, ArF excimer laser light with a wavelength of 193 nm, KrF excimer laser light with a wavelength of 248 nm, or harmonics of laser light output from a solid-state laser (semiconductor laser or the like). Illumination light IL is, for example, light that is pulsed at a frequency of several kHz or about 1 to 2 MHz. In the following description, the X axis and the Y axis are taken along the first and second arrangement directions in which the plurality of pixels 32 are orthogonal, and the Z axis is taken in the direction orthogonal to the X axis and the Y axis.

In FIG. 1A, the main body 30 of the spatial light modulator 28 is arranged in a two-dimensional lattice shape in the X and Y directions with a base member 31 made of a rectangular box-like insulator having an open top surface. A partition member 33 made of an insulator having a plurality of square openings formed therein, a plurality of connecting portions 33S for supporting the partition member 33 in the base member 31, and an upper surface of the base member 31 and the illumination light IL Has a flat cover glass 35 (see FIG. 1B). The partition member 33 may be supported from the bottom surface side of the base member 31. The cover glass 35 is made of a material that transmits the illumination light IL, such as quartz or fluorite (CaF ₂ ).

In the present embodiment, a plurality of pixels 32 are arranged along a bottom surface (hereinafter referred to as an array surface DP) parallel to the XY plane of the cover glass 35, and the entire surface of the bottom surface (array surface DP) of the cover glass 35 is A transparent electrode 36 (see FIG. 2) having a thickness enough to transmit the illumination light IL is formed. The transparent electrode 36 is grounded. The transparent electrodes, ITO (Indium Tin Oxide: indium tin oxide), tin oxide (Sn0 _2), indium oxide (In ₂ O _3), gallium added tin oxide (GZO), aluminum doped tin oxide (AZO), or Other materials can be used.

  The partition wall member 33 is a set of square cylindrical partition wall portions 33a that are in close contact with each other in the X and Y directions and are arranged at equal pitches (periods) px and py (px = py). The partition wall 33a has an inner surface with a square cross section surrounded by an inner surface along the Z direction perpendicular to the arrangement surface DP, that is, two surfaces parallel to the XZ surface and two surfaces parallel to the YZ surface. The cell part 34 is comprised from the partition part 33a. The pitch px of the arrangement of the pixels 32 is, for example, about 10 to 1 μm. As an example, the arrangement number of the pixels 32 in the X direction is several thousand to tens of thousands, and the arrangement number in the Y direction is 1/10 of the arrangement number in the X direction. Degree. In FIG. 1A, each pixel 32 is shown enlarged. The number of the pixels 32 arranged in the X direction and the Y direction is arbitrary, and the cross-sectional shape of the partition wall 33a (the shape of the pixel 32) may be a rectangle. The pitches px, py May be different from each other.

The base member 31 is an insulator made of, for example, a fluoropolymer (fluorine polymer), a material in which an insulating layer such as silicon oxide (SiO ₂ ) or silicon nitride (eg, Si ₃ N ₄ ) is formed on the surface of a silicon substrate, or ceramics. Etc. can be formed. The partition member 33 can be formed from, for example, silicon oxide, silicon nitride, ceramics, or the like.
In the present embodiment, each pixel 32 has a reflection surface 37a parallel to the XY plane that reflects the incident illumination light IL. Then, by using electrowetting as described later, each pixel 32 changes the phase of the illumination light IL1 incident vertically (in the Z direction) to a first predetermined phase δ, like the pixel 32 at the position A1. As shown in the pixel 32 at the position A2, the incident light IL2 is reflected by changing the phase of the incident illumination light IL2 by a phase different from the phase δ by 180 ° (π (rad)). A plurality of states including the second state can be set. The pixel 32 in the first state is also referred to as a pixel 32 (0), and the pixel 32 in the second state is also referred to as a pixel 32 (π).

  Next, FIG. 2 is an enlarged perspective view representatively showing only one pixel 32 in the main body 30 of the spatial light modulator 28 of FIG. FIG. 2 also shows a block diagram of the modulation control unit 48 of the spatial light modulator 28. FIG. 3A is an enlarged cross-sectional view representatively showing only two pixels 32 at positions A1 and A2 in the main body 30 of FIG. In FIG. 3A, each pixel 32 is formed on the bottom surface (array surface DP) of the cover glass 35 so as to cover the entire surface of the cell portion 34 and the window portion 34a above (−Z direction) the cell portion 34. The transparent electrode 36, the bottom electrode 37 formed of a thin conductive film formed in the Y direction on the bottom surface 34b of the cell portion 34, and the insulator thin film (hereinafter referred to as insulation) formed so as to cover the bottom electrode 37. 50A, and the first liquid Lqa and the second liquid Lqb that are accommodated in the cell part 34 without being mixed and have different refractive indexes and dielectric constants (relative dielectric constants).

  In the present embodiment, as an example, the refractive index na of the first liquid Lqa is larger than the refractive index nb of the second liquid Lqb, and the relative dielectric constant εa of the first liquid Lqa is larger than the relative dielectric constant εb of the second liquid Lqb. For example, it is about 10 to 40 times larger. The liquids Lqa and Lqb are liquids that transmit the illumination light IL. In addition, on the bottom surface of the base member 31 that accommodates the partition wall member 33, as an example, a discharge portion 51 having an opening that is opened and closed for discharging a liquid at the time of manufacture is provided.

  As the conductor forming the bottom electrode 37, metal, polysilicon or the like can be used. The insulating film 50A is thick enough to transmit illumination light, and the insulating film 50A prevents direct contact between the liquids Lqa and Lqb and the bottom electrode 37. The surface of the bottom electrode 37 is a reflecting surface 37a that reflects illumination light. When the bottom electrode 37 is polysilicon, a dielectric multilayer film that reflects illumination light may be formed on the reflective surface 37a. As a material of the insulating film 50A, for example, fluorine-added silicon oxide (SiOF), carbon-added silicon oxide (SiOC), ceramics, or the like can be used.

In FIG. 2, the width of the inner surface of the cell part 34 in the X direction and the Y direction is equally a1, and the depth of the cell part 34 (the distance in the Z direction from the bottom surface of the transparent electrode 36 to the surface of the insulating film 50A) is ah. To do. At this time, the length of the bottom electrode 37 (reflection surface 37a) in the Y direction is approximately a1, and the width a4 in the X direction is approximately a1 / 2.
As an example, the depth ah of the cell part 34 is approximately 1000 nm. When the width a1 in the cell part 34 is approximately 1 μm (1000 nm), the thickness a3 of the insulating film 50A is approximately 100 nm, the width a4 in the X direction of the bottom electrode 37 is approximately 500 nm, and the bottom surface in the cell part 34 is the bottom surface. The width a5 in the X direction of the two rectangular regions sandwiching the electrode 37 in the X direction is approximately 250 nm. Further, the second liquid Lqb is distributed on the surface of the bottom electrode 37 (insulating film 50A) in the cell part 34, and the boundary surface between the liquids Lqa and Lqb is parallel to the XY plane, and the first liquid Lqa is in the Z direction. Assuming that the depth (thickness) is a2 and the depth (thickness) in the Z direction of the second liquid Lqb is d, the sum of the depth a2 and the depth d is as follows: It becomes ah.

ah = a2 + d (1)
The depth d is set according to the wavelength of the illumination light IL (details will be described later), and the depth a2 is set based on the expression (1) and the depth d. As an example, the depth a2 is set to about 745 nm.
The partition wall member 33 formed with the bottom electrodes 37 for the plurality of pixels 32 and the wirings (not shown) for these electrodes according to the present embodiment is manufactured using, for example, MEMS (Microelectromechanical Systems) technology. Is possible. The main body 30 including the base member 31 and the partition wall member 33 can be integrally manufactured using the MEMS technology (and semiconductor device manufacturing technology).

  In this embodiment, in FIG. 3A, the transparent electrodes 36 of the plurality of pixels 32 are commonly grounded (the ground level is set to 0V). As an example, the + Z direction is the vertical direction, and the specific gravity of the second liquid Lqb is lighter than the specific gravity of the first liquid Lqa. In the pixel 32 in the first state irradiated with the illumination light IL1 at the position A1, the voltage 0 is applied to the bottom electrode 37, and the potentials of the transparent electrode 36 and the bottom electrode 37 are the same. And At this time, the second liquid Lqb is distributed at the depth d on the bottom electrode 37 side in the cell portion 34, and the illumination light IL1 incident on the pixel 32 at the position A1 has the first liquid Lqa and the depth d. The liquid 2 passes through the liquid Lqb, is reflected by the surface (reflection surface 37a) of the bottom electrode 37, and is returned to the window 34a side.

  On the other hand, in the pixel 32 in the second state irradiated with the illumination light IL2 at the position A2, a predetermined positive voltage V1 higher than the ground level is applied to the bottom electrode 37, and the transparent electrode The potential difference between 36 and the bottom electrode 37 is V1. When the first liquid Lqa is pure water (relative permittivity is approximately 80) and the width of the inner surface of the cell portion 34 is approximately 1 μm, the voltage V1 is, for example, 180V. At this time, since the relative dielectric constant εa of the first liquid Lqa is approximately 10 times or more than the relative dielectric constant εb of the second liquid Lqb, the electrostatic force acting between the first liquid Lqa and the bottom electrode 37 is reduced. The attractive force (electrostatic attractive force) is larger than the electrostatic attractive force acting between the second liquid Lqb and the bottom electrode 37. Therefore, based on the electrowetting action, the transparent electrode 36 and the surface 37a of the bottom electrode 37 within the cell portion 34 of the pixel 32 at the position A2 have an effective area 37b having the same width in the X direction as the surface 37a. The area in between is filled with the first liquid Lqa. The illumination light IL2 incident on the pixel 32 at the position A2 passes through only the first liquid Lqa, is reflected by the surface of the bottom electrode 37 (reflection surface 37a), and is returned to the window 34a side.

In the present embodiment, the reflection of the pixel 32 (π) in the second state with respect to the amount of change in the phase of the illumination light IL1 reflected by the reflection surface of the bottom electrode 37 of the pixel 32 (0) in the first state. The amount of change in the phase of the illumination light IL2 reflected by the surface differs by 180 ° (π). For this purpose, in the pixel 32 (0) in the first state, the amount of change in the phase of the illumination light IL1 that reciprocates in the Z direction through the portion of the second liquid Lqb (refractive index nb) having the depth d is equal to the second amount. In the state of the pixel 32 (π), 180 ° (π) (optical path length) with respect to the amount of change in the phase of the illumination light IL2 reciprocating in the Z direction in the portion of the first liquid Lqa (refractive index na) having the depth d ½ wavelength). Assuming that the wavelengths of the illumination lights IL1 and IL2 are λ, the conditions for setting the pixels 32 in the first state and the second state as described above are as follows.
2d (na−nb) = λ / 2 (2), d = λ / {4 (na−nb)} (3)
Examples of the first liquid Lqa and the second liquid Lqb that can satisfy the condition of the expression (2) or the expression (3) are shown in the following Table 1.

  The relative dielectric constant is a value for an AC signal of, for example, 100 Hz or more. Fluorinate (registered trademark), hydrofluoroether (HFE), and perfluoropolyether (PFPE) are fluorine-based oils, all having a refractive index smaller than that of pure water and a relative dielectric constant of 1/10 to 1 of pure water. / 40 or so. Further, these fluorinated oils (fluorinated inert liquids) do not mix with water (immiscible with water). Therefore, in the present embodiment, pure water can be used as the first liquid Lqa, and florinate, HFE, or PFPE can be used as the second liquid Lqb. Table 1 shows the refractive index difference Δn of each fluorinated oil with pure water and the value (nm) of the depth d (thickness) for satisfying the formula (2). From Table 1, since the depth d for satisfying the expression (2) is 255 to 345 nm, the size (arrangement pitch) of each pixel 32 can be about 1 μm. Fluorinert has the smallest relative dielectric constant and the smallest refractive index, and the required depth d (= 255 nm) is the smallest. Therefore, fluorinate is most preferable as the second liquid Lqb.

  Table 1 also lists the refractive index and relative dielectric constant of decalin, which is a high refractive index liquid. Decalin has a refractive index larger than that of pure water and a relative dielectric constant smaller than that of pure water, and is immiscible with water. Therefore, for example, pure water can be used as the first liquid Lqa, and decalin can be used as the second liquid Lqb. It is also possible to use decalin as the first liquid Lqa and use fluorinate as the second liquid Lqb. Furthermore, as the first liquid Lqa and the second liquid Lqb, it is possible to use arbitrary liquids having different refractive indexes and relative dielectric constants and immiscible with each other. Note that the liquids Lqa and Lqb preferably have a transmittance of about pure water with respect to the illumination light IL.

  Next, in FIG. 2, the modulation control unit 48 is a control unit 52 that is a part of a computer that controls the distribution of the states (first state or second state) of the plurality of pixels 32 in FIG. And the SRAM 54, which is a memory storing data corresponding to the distribution of the states of the plurality of pixels 32 (voltage applied to the bottom electrode 37), and the same number of amplifiers 55A, 55B as the pixels 32 that amplify the output of the SRAM 54. , 55C,... And a ground line for grounding the transparent electrodes 36 of all the pixels 32 at once. Outputs of the amplifiers 55A and 55B are supplied to the bottom electrode 37 of the corresponding pixel 32 via signal lines and wiring (not shown) provided in the cell part 34, respectively. In the present embodiment, a voltage 0 (here, ground level) (first state) or the voltage V1 (second state) is applied to each bottom electrode 37. Note that a shift register can be used instead of the SRAM 54.

  In the present embodiment, the SRAM 54 stores in advance a pattern that changes digital data corresponding to the states of all the pixels 32 in time series, and the control unit 52 has a predetermined drive frequency (for example, 1 to 2 MHz). The data of the corresponding series of addresses in the SRAM 54 is output to the amplifier 55A or the like. In response to this, for example, as shown in FIG. 1A, a plurality of pixels 32 arranged in a two-dimensional array form a pixel 32 (0) in the first state or a second shaded line. It is set to one of the pixels 32 (π) in the state. Therefore, the arrangement of the plurality of pixels 32 in the first state or the second state can be set to an arbitrary arrangement with one pixel 32 as a unit at a predetermined time interval.

  Next, an example of a method for manufacturing the main body 30 of the spatial light modulator 28 of the present embodiment will be described with reference to FIGS. First, by using MEMS technology or the like, the partition wall member 33 formed with a plurality of cell portions 34 excluding the liquids Lqa and Lqb, the bottom surface electrode 37, etc. is manufactured from the main body portion 30 in FIG. Then, the cover glass 35 on which the transparent electrode 36 is formed and the base member 31 provided with the discharge part 51 are manufactured.

  Next, as shown in FIG. 3B, a first liquid Lqa having a depth a2 and a second liquid Lqb having a depth d are sequentially supplied to the upper surface of the transparent electrode 36 of the cover glass 35. A frame-like member (not shown) is placed around the upper surface of the transparent electrode 36 so that the liquid does not leak to the outside, and the rod-like electrodes (not shown) inserted into the liquids Lqa and Lqb are grounded. The liquids Lqa and Lqb are stably held on the upper surface of the transparent electrode 36 by applying a predetermined positive potential to the transparent electrode 36. As an example, the thicknesses of the liquids Lqa and Lqb are determined from the volume of each liquid supplied into the frame member and the area within the frame member.

  Then, for example, in a vacuum environment, the window part 34a of the cell part 34 of the partition wall member 33 is directed to the second liquid Lqb on the cover glass 35, and the partition wall member 33 is brought into contact with the transparent electrode 36 on the cover glass 35. The potential of the transparent electrode 36 is set to zero. Furthermore, the partition member 33 and the cover glass 35 are fixed by, for example, adhesion. Thereafter, for example, in an atmospheric pressure environment, the open end of the base member 31 is brought into contact with the cover glass 35 so as to cover the partition member 33, and the support member 33S of the partition member 33 and the base member 31 are fixed by adhesion or the like. The body 31 is completed by fixing the member 31 and the cover glass 35 and discharging the liquid inside the base member 31 through the discharge portion 51.

The effects and the like of this embodiment are as follows.
(1) The spatial light modulator 28 that modulates the illumination light IL incident on the array surface DP of the present embodiment includes a cell unit 34 having partition walls 33a along the Z direction across the array surface DP, and First and second liquids Lqa and Lqb having different refractive indices and dielectric constants contained therein, and a transparent electrode 36 (first electrode) provided on the entire surface of the window part 34a into which the illumination light IL of the cell part 34 enters. The voltage applied to the bottom electrode 37 (second electrode) also serving as a reflection part for the illumination light IL provided on a part of the bottom surface 34b of the cell part 34 and the transparent electrode 36 and the bottom electrode 37 of the cell part 34 is controlled. A modulation control unit 48. Then, the modulation control unit 48 controls the ratio of the thicknesses of the liquids Lqa and Lqb in the cell unit 34 by the voltage applied to the electrodes 36 and 37 (potential difference between the electrodes 36 and 37). The optical path length of the illumination light IL reflected by the bottom electrode 37 (reflecting portion), and consequently the phase of the reflected light, is controlled.

  According to the spatial light modulator 28 of the present embodiment, the liquid Lqa having a high dielectric constant is attracted to the electrode 37 by the voltage applied to the electrodes 36 and 37 provided in the cell portion 34 (potential difference between the electrodes 36 and 37). When the force acts in the direction to be generated, the ratio of the thicknesses of the liquids Lqa and Lqb in the cell part 34 can be controlled. Further, since the refractive indexes of the liquids Lqa and Lqb are different, the illumination light IL reflected by the pixel 32 (optical element) including the cell unit 34 is based on the difference in thickness and refractive index between the two liquids Lqa and Lqb. The optical path length and thus the phase can be controlled.

Furthermore, since each pixel 32 is partitioned by the partition wall 33a, the influence of electrostatic force between the pixels 32 and the flow of liquid between the pixels 32 are suppressed, and high resolution is obtained.
The transparent electrode 36 may be provided on a part of the window portion 34 a of the cell portion 34, and the bottom electrode 37 may be provided on the entire bottom surface 34 b of the cell portion 34.
(2) In the present embodiment, the positive voltage V1 is applied to the bottom electrode 37 in the pixel 32 in the second state. However, a negative voltage may be applied to the bottom electrode 37 in the pixel 32 in the second state.

(3) In addition, since the bottom electrode 37 also serves as a reflecting portion, the configuration of the pixel 32 is simple.
Instead of providing the bottom electrode 37, an electrode may be provided on the side surface of the cell portion 34, and a reflective member may be arranged instead of the bottom electrode 37. At this time, the phase of the reflected light can be controlled by controlling the ratio of the thicknesses of the liquids Lqa and Lqb above the reflecting member in the cell portion 34 by the potential difference between the electrode on the side surface and the transparent electrode 36.

  (4) In the present embodiment, each pixel 32 is set to the first or second state. However, the phase of the reflected illumination light IL is set to the pixel 32 with respect to the first state. You may set to other different states by values other than 180 degrees (for example, 45 degrees, 90 degrees, 135 degrees, etc.). Furthermore, the phase of the illumination light IL reflected by each pixel 32 may be set to be different from the phase of the first state by an arbitrary phase.

  (5) Although the spatial light modulator 28 of the present embodiment is a reflection type, for example, in FIG. 2, instead of providing the bottom electrode 37, an electrode is provided on the side surface of the cell part 34, and the insulating film 50A is transmissive. By using this glass substrate, each pixel 32 can be a transmissive pixel. In this case, since the illumination light IL is only transmitted once through each cell portion 34, the depth of the second liquid Lqb for setting each pixel 32 to the first state or the second state described above. The length d is twice the value determined by the above formula (2) or formula (3), as shown by the following formula.

d (na−nb) = λ / 2 (4), d = λ / {2 (na−nb)} (5)
(6) Although the spatial light modulator 28 of the present embodiment is a phase modulation type, in FIG. 2, the transmittance and the dielectric constant are different from those of the first liquid Lqa in the cell part 34 together with the first liquid Lqa. By accommodating another liquid Lqc (second liquid), the spatial light modulator 28 can be of an amplitude modulation type (or intensity modulation type). As the liquid Lqc, for example, a liquid having substantially zero transmittance with respect to the illumination light IL obtained by adding a dye that absorbs the illumination light IL to the above-described fluorine-based oil can be used. In this configuration, the transmittance of the illumination light IL reflected by the pixel 32 (optical element) including the cell unit 34 can be controlled based on the difference in thickness and transmittance between the two liquids Lqa and Lqc. Specifically, in the first state, the amount of reflected light from the pixel 32 is almost zero, and in the second state, the amount of reflected light from the pixel 32 is large. Further, in such an amplitude or intensity modulation type spatial light modulator, an electrode is provided on the side surface of the cell portion 34 instead of the bottom surface electrode 37, and the insulating film 50A is a glass substrate, whereby each pixel is a transmission type. You can also
(7) Since the pixels 32 of the spatial light modulator 28 are a two-dimensional array, for example, when applied to an exposure apparatus, a pattern with a large area can be exposed or illuminated. In the spatial light modulator 28, the pixels 32 may be arranged in a line (one dimension) in the X direction or the Y direction.

In the above embodiment, the following modifications are possible.
First, in the above embodiment, an electrode (bottom electrode 37 or the like) is provided on the bottom surface or side surface of the cell portion 34 of the pixel 32. As shown in the spatial light modulator 28A of the first modification example in FIG. In each pixel 32A of the main body 30A, a bottom electrode 37 (second electrode) is provided on the bottom part 34b of the cell part 34, and X is formed on the side surface of the part close to the window 34a (transparent electrode 36) in the cell part 34. Side wall electrodes 39A and 39B (third electrodes) made of a pair of conductive thin films may be provided so as to face each other in a direction (a direction perpendicular to the longitudinal direction of bottom electrode 37). The conductor is, for example, metal or polysilicon, and the side wall electrodes 39A and 39B are rectangular thin films elongated in the lateral direction (Y direction). The side wall electrodes 39 </ b> A and 39 </ b> B are electrically connected by wiring provided in the cell portion 34. In FIG. 4, parts corresponding to those in FIG.

  In FIG. 4, an insulating film 50B similar to the insulating film 50A covering the surface of the bottom electrode 37 is provided on the surfaces of the side wall electrodes 39A and 39B. In the cell part 34, the first liquid Lqa and the second liquid Lqb are accommodated. With the boundary surfaces of the liquids Lqa and Lqb parallel to the XY plane, the depths of the liquids Lqa and Lqb are a2 and d, respectively. In the present embodiment, the width in the Y direction of the side wall electrodes 39A and 39B is a1 (the width of the inner surface of the cell portion 34), and the width a6 in the Z direction of the side wall electrodes 39A and 39B is greater than the depth a2 of the first liquid Lqa. Is also set larger. The width a1 'in the X direction of the inner surface of the cell portion 34 is set smaller than the width a1 by the thickness of the electrodes 39A and 39B and the insulating film 50A.

  As an example, when the width a1 in the Y direction in the cell part 34 is approximately 1000 nm, the thickness of the electrodes 39A, 39B and the insulating film 50A is approximately 50 nm, respectively, and the width a1 ′ in the X direction of the cell part 34 is approximately 800 nm. It is. As an example, when the depth a2 of the first liquid Lqa is 745 nm and the depth d of the second liquid Lqb is 255 nm, the width a6 in the Z direction of the sidewall electrodes 39A and 39B is approximately 800 nm, and the sidewall electrodes 39A and 39B. The distance a7 in the Z direction between the lower end of each and the surface of the insulating film 50A is approximately 200 nm. Further, the width a4 in the X direction of the bottom electrode 37 is approximately 500 nm, and the width a5 'in the X direction of the two regions sandwiching the bottom electrode 37 in the X direction at the bottom in the cell portion 34 is approximately 150 nm.

  Further, the modulation control unit 48A of the spatial light modulator 28A has a voltage conversion unit 56 corresponding to each pixel 32A, the output unit being connected to the side wall electrodes 39A and 39B and the input unit being connected to the amplifier 55A and the like. The voltage converter 56 outputs the voltage V2 when the output of the amplifier 55A or the like is 0 (ground level), and outputs 0 when the output of the amplifier 55A or the like is V1. Other configurations are the same as those in the above embodiment, and the transparent electrode 36 is grounded (the ground level is set to 0).

  In this first modification, as shown in FIG. 5B, when the voltages of the bottom electrode 37 and the side wall electrodes 39A and 39B are virtually zero, the contact angle θc2 of the first liquid Lqa with respect to the insulating film 50B Is larger than 90 °, and the thickness of the first liquid Lqa is larger above the bottom electrode 37 (reflection surface) than in other regions. At this time, as shown in FIG. 5A, in the first state pixel 32A (pixel 32A (0)) irradiated with the illumination light IL1, a voltage of 0 is applied to the bottom electrode 37, and the side wall A positive voltage V2 is applied to the electrodes 39A and 39B. In this state, the first liquid Lqa is held in a region near the side wall electrodes 39A and 39B in the cell portion 34 by electrostatic attraction from the side wall electrodes 39A and 39B. The contact angle θc1 of the first liquid Lqa with respect to the insulating film 50B is approximately 90 °.

  In other words, in the pixel 32A in the first state, a voltage V2 is applied to the side wall electrodes 39A and 39B so that the contact angle θc1 of the first liquid Lqa with respect to the insulating film 50B is approximately 90 °. The voltage V2 may be smaller than the positive voltage V1 applied to the bottom electrode 37 in the second state. The voltage V2 is 25V, for example. At this time, the boundary surface between the liquids Lqa and Lqb in the cell part 34 is substantially parallel to the XY plane, and the second liquid Lqb is distributed at a depth d on the bottom electrode 37 side in the cell part 34. The illumination light IL1 incident on the pixel 32A passes through the first liquid Lqa and the second liquid Lqb having a depth d, is reflected by the surface (reflection surface) of the bottom electrode 37, and is returned to the cover glass 35 side.

  On the other hand, as shown in FIG. 5C, in the pixel 32A (pixel 32A (π)) in the second state irradiated with the illumination light IL2, the bottom electrode 37 is higher than the ground level. A positive voltage V1 is applied, and the voltages of the side wall electrodes 39A and 39B are set to zero. At this time, the relative permittivity εa of the first liquid Lqa is approximately 10 times or more than the relative permittivity εb of the second liquid Lqb, and the first liquid Lqa has a force in a direction attracted toward the bottom electrode 37. work. Further, when the voltages of the side wall electrodes 39A and 39B are set to 0, the contact angle θc3 of the first liquid Lqa with respect to the insulating film 50B becomes larger than 90 °. As a result, the boundary surface between the first liquid Lqa and the second liquid Lqb is a concave surface, and the distance between the bottom electrode 37 and the first liquid Lqa is shortened. Since the electric field becomes stronger as the distance between the bottom electrode 37 and the first liquid Lqa is shorter, the force with which the first liquid Lqa is attracted toward the bottom electrode 37 becomes larger. The first liquid Lqa is drawn toward the bottom electrode 37, and finally, the region between the transparent electrode 36 and the surface of the bottom electrode 37 in the cell portion 34 of the pixel 32A is almost filled with the first liquid Lqa. . In this state, the illumination light IL2 incident on the pixel 32A substantially passes only the first liquid Lqa, is reflected by the surface (reflection surface) of the bottom electrode 37, and is returned to the cover glass 35 side.

  Also in this modified example, since the depth d of the second liquid Lqb satisfies the formula (2), the phase change of the illumination light IL1 reflected by the reflection surface of the bottom electrode 37 of the pixel 32A (0) in the first state. The amount of change in phase of the illumination light IL2 reflected by the reflecting surface of the bottom electrode 37 of the pixel 32A (π) in the second state differs from the amount by 180 ° (π). Then, by switching the set of voltages applied to the bottom electrode 37 and the side wall electrodes 39A and 39B between the first state (0, V2) and the second state (V1, 0) at high speed, the pixel 32A can be switched at high speed between the first state and the second state.

  In this modification, when the voltages of the side wall electrodes 39A and 39B are 0, the contact angle θc2 of the first liquid Lqa is larger than 90 ° as shown in FIG. For this reason, the voltage V1 applied to the bottom electrode 37 in order to put the pixel 32A in the second state can be smaller than the voltage applied to the bottom electrode 37 of the above-described embodiment (FIG. 2). For example, when the first liquid Lqa is pure water and the width a1 of the inner surface of the cell portion 34 is approximately 1 μm, the voltage V1 applied to the bottom electrode 37 in FIG. 5C is approximately 90 V (in the embodiment of FIG. 2). It can be reduced to about 1/2 of 180V). Therefore, the circuit of the modulation control unit 48A can be easily integrated and the amount of generated heat can be reduced.

  Next, in the modification of FIG. 4, a pair of side wall electrodes 39A and 39B is provided on the side surface in the cell portion 34A. Furthermore, in addition to the pair of side wall electrodes 39A and 39B in the X direction on the side surface in the cell part 34, as shown by the pixel 32B of the main body part 30B of the spatial light modulator 28B of the second modification of FIG. A pair of side wall electrodes 39C and 39D made of a conductive thin film disposed so as to face each other in the Y direction may be provided, and the insulating film 50B may be provided so as to cover the side wall electrodes 39C and 39D. In this modification, the shape of the side wall electrodes 39C and 39D is the same as that of the side wall electrodes 39A and 39B, and the width in the Y direction in the cell part 34 is the same as the width in the X direction (width a1 'in FIG. 4). The side wall electrodes 39A to 39D are electrically connected by wiring provided in the cell portion 34, and the same voltage as that of the side wall electrodes 39A and 39B is applied to the side wall electrodes 39C and 39D. Other configurations are the same as those of the modification of FIG.

In the modification of FIG. 6, the set of voltages applied to the bottom electrode 37 and the side wall electrodes 39 </ b> A to 39 </ b> D is set at a high speed between (0, V2) in the first state and (V1,0) in the second state. By switching, the pixel 32B can be switched at high speed between the first state and the second state in which the phases of reflected light are 180 ° different from each other.
Furthermore, according to the pixel 32B of this modification, the side wall electrodes 39A to 39D surround the inside of the cell part 34, so that the voltage V1 applied to the bottom electrode 37 in the second state can be further reduced. Specifically, when the first liquid Lqa is pure water and the width in the cell portion 34 is approximately 800 nm, the voltage V1 applied to the bottom electrode 37 in the second state is approximately 60 V (90 V in the modification of FIG. 4). Can be reduced to about 2/3). Therefore, it is easier to increase the integration of the circuit of the modulation control unit, and the amount of heat generation can be reduced.

  Next, in the above embodiment and its modifications, the bottom electrode 37 and the like of the cell part 34 of the pixel 32 are flat. On the other hand, as shown in the spatial light modulator of the third modification of FIG. 7, in each pixel 32 </ b> C of the main body portion, on the surface of the bottom electrode 37 </ b> A made of a conductor provided on the bottom surface portion of the cell portion 34, A projecting electrode portion 38 having a roof shape elongated in the Y direction where the cross-sectional shape in a plane parallel to the XZ plane is triangular may be provided. In this case, the surface of the bottom electrode 37A is a reflecting surface that reflects the illumination light IL. Further, a roof-shaped convex portion 50Ca is also formed in a portion covering the protruding electrode portion 38 of the insulating film 50C (made of the same material as the insulating film 50A in FIG. 2) provided on the surface of the bottom electrode 37A. 7 and 8A to 8C, portions corresponding to those in FIGS. 2 and 3A are denoted by the same reference numerals, and detailed description thereof is omitted.

  In FIG. 7, the first liquid Lqa and the second liquid Lqb are accommodated in the cell portion 34. Other configurations are the same as those of the embodiment of FIG. With the boundary surface between the liquids Lqa and Lqb in the pixel 32C parallel to the XY plane, the height a10 of the convex portion 50Ca of the insulating film 50C is set lower than the depth of the second liquid Lqb. As an example, when the width in the cell portion 34 is approximately 1000 nm, the width a8 in the X direction of the bottom surface of the protruding electrode portion 38 is approximately 200 nm, and two portions X sandwiching the protruding electrode portion 38 of the bottom electrode 37A in the X direction. The width a9 in the direction is approximately 150 nm, and the height a10 of the convex portion 50Ca (the height of the protruding electrode portion 38) is approximately 200 nm.

  In the third modification, as shown in FIG. 8B, in the first state pixel 32C (pixel 32C (0)) irradiated with the illumination light IL1, a voltage 0 is applied to the bottom electrode 37. The second liquid Lqb is distributed to the bottom electrode 37A side in the cell portion 34, and the boundary surface between the liquids Lqa and Lqb is parallel to the XY plane. Then, the illumination light IL1 incident on the pixel 32C passes through the first liquid Lqa and the second liquid Lqb having a depth d satisfying the expression (2), and is reflected by the surface (reflection surface) of the bottom electrode 37A. Returned to the 35 side. At this time, among the surface of the bottom electrode 37A, the illumination light IL1 reflected by the surface 38a of the protruding electrode portion 38 is absorbed or scattered inside the cell portion 34 and hardly returned to the cover glass 35 side. Therefore, using the widths a8 and a9 in FIG. 7, the usage efficiency of the illumination light IL1 is approximately 60% as compared with the embodiment in FIG.

2 · a9 / (a8 + 2 · a9) = 0.6 = 60 (%) (6)
Further, as shown in FIG. 8C, in the pixel 32C in the second state (pixel 32C (π)) irradiated with the illumination light IL2, the bottom electrode 37A has a positive voltage higher than the ground level. V1 is applied. For this reason, the region between the transparent electrode 36 and the surface of the bottom electrode 37A in the cell portion 34 of the pixel 32C is almost filled with the first liquid Lqa. In this state, of the illumination light IL2 incident on the pixel 32C, the illumination light reflected by the surface (reflection surface) of the bottom electrode 37A excluding the surface 38a of the protruding electrode portion 38 substantially passes only the first liquid Lqa. Then, it is returned to the cover glass 35 side. Then, with respect to the amount of change in the phase of the illumination light IL1 reflected by the reflecting surface of the bottom electrode 37A of the pixel 32C (0) in the first state, the bottom electrode 37A of the pixel 32C (π) in the second state The amount of change in phase of the illumination light IL2 reflected by the reflecting surface is different by 180 ° (π).

  In this modified example, when the voltage V1 is applied to the bottom electrode 37A, the electric field is strong in the vicinity of the protruding electrode part 38, so that the force acting on the liquid Lqa is increased in the vicinity of the protruding electrode part 38. Therefore, when the voltage V1 is applied, first, as shown in FIG. 8B, the boundary surface between the liquids Lqa and Lqb intersects the surface 38a (convex portion 50Ca) of the protruding electrode portion 38. In other words, when the protruding electrode portion 38 is provided, the electrostatic attraction (electric field) from the bottom electrode 37A to the first liquid Lqa increases even if the voltage V1 is small, and the pixel 32C is brought into the second state with the small voltage V1. Can be set. For example, when the first liquid Lqa is pure water and the width of the inner surface of the cell portion 34 is approximately 1 μm, the voltage V1 applied to the bottom electrode 37A in FIG. 8C is approximately 60 V (180 V in the embodiment of FIG. 2). 1/3). Therefore, the circuit of the modulation control unit can be easily integrated and the amount of heat generated can be reduced.

  As described above, in the modified example of FIG. 7, the roof-type protruding electrode portion 38 is provided on the surface of the bottom electrode 37A. However, as shown in the pixel 32D of the fourth modified example of FIG. A quadrangular pyramid (pyramid) protruding electrode portion 38A having a square bottom surface surrounded by four sides parallel to the X direction and the Y direction may be provided in the center of the surface 37Ba of the bottom surface electrode 37B of the bottom surface portion 34. Good. At this time, the convex portion 50Da is also formed in the portion covering the protruding electrode portion 38A of the insulating film 50D provided on the surface of the bottom electrode 37B. As shown in FIG. 9B, the width a8 in the X direction and the Y direction of the bottom surface of the protruding electrode portion 38A (convex portion 50Da) is the same as the width a8 in the X direction of the protruding electrode portion 38 in FIG. The height a10 of the electrode part 38A (projection 50Da) is the same as the height a10 of the protruding electrode part 38. Also in this modification, the voltage V1 applied to the bottom electrode 37B in FIG. 9 can be reduced in order to set the pixel 32D to the second state, as in the modification in FIG.

In addition, instead of the quadrangular pyramidal protruding electrode portion 38A on the surface of the bottom electrode 37B, the sectional shape becomes smaller toward the window portion (transparent electrode 36) side of the cell portion 34, for example, like a conical protruding electrode portion. A convex electrode portion may be provided. Accordingly, the voltage V1 applied to the bottom electrode 37B in order to set the pixel 32D to the second state can be reduced.
Next, the pixel 32E of the fifth modified example shown in FIG. 10 includes a bottom electrode 37A having the roof-type protruding electrode portion 38 of FIG. 7 as the bottom electrode in the pixel 32B having the four side wall electrodes 39A to 39D in FIG. It is equipped with. In this case, an insulating film 50C having a convex portion 50Ca is formed as an insulating film covering the bottom electrode 37A. According to this modification, the voltage V1 applied to the bottom electrode 37A to set the pixel 32E to the second state can be reduced to approximately 30 V (approximately 1/6 of 180 V in the embodiment of FIG. 2).

  Further, in the pixel 32F of the sixth modification shown in FIG. 11, the bottom electrode 37B having the pyramidal protruding electrode portion 38A of FIG. 9 is used as the bottom electrode in the pixel 32B having the four side wall electrodes 39A to 39D in FIG. It is provided. In this case, the insulating film 50D having the convex portions 50Da is formed as the insulating film covering the bottom electrode 37B. According to this modification, the voltage V1 applied to the bottom electrode 37B in order to set the pixel 32F to the second state can be reduced to approximately 30V (approximately 1/6 of 180V in the embodiment of FIG. 2).

[Second Embodiment]
The second embodiment will be described below with reference to FIG. 12, parts corresponding to those in FIGS. 1 (A) to 2 are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 12 shows a schematic configuration of a maskless exposure apparatus EX according to the present embodiment. In FIG. 12, an exposure apparatus EX includes an exposure light source 2 that emits pulsed light, an illumination optical system ILS that illuminates a surface to be irradiated with exposure illumination light (exposure light) IL from the light source 2, and an illumination optical system ILS. A mask pattern generating spatial light modulator 28 having a main body 30 having a plurality of pixels 32 arranged in a two-dimensional array on the irradiation surface or a surface in the vicinity thereof, and a modulation control unit 48. . Further, the exposure apparatus EX receives illumination light IL having a variable phase distribution generated by the plurality of pixels 32 of the spatial light modulator 28, and a spatial image (device pattern) formed corresponding to the phase distribution. ) On the surface of the wafer W (substrate), a wafer stage WST for positioning and moving the wafer W, a main control system 40 comprising a computer for overall control of the operation of the entire apparatus, and various controls. System.

  Hereinafter, in FIG. 12, the Z axis is set in parallel to the optical axis AX of the projection optical system PL, and in a plane perpendicular to the Z axis (in this embodiment, substantially parallel to the horizontal plane), it is parallel to the paper surface of FIG. A description will be given by setting the Y axis in the direction and the X axis in the direction perpendicular to the paper surface of FIG. In addition, the angles around the X axis, the Y axis, and the Z axis are also called angles in the θx direction, the θy direction, and the θz direction, respectively. The relationship between the coordinate system (X, Y, Z) and the main body 30 of the spatial light modulator 28 is the same as in FIG. In the present embodiment, the wafer W is scanned in the Y direction (scanning direction) during exposure.

  As the light source 2, an ArF excimer laser light source (wavelength 193 nm) is used. As the light source 2, a KrF excimer laser light source, a solid pulse laser light source that generates harmonics of laser light output from a YAG laser or a solid-state laser (semiconductor laser or the like), or the like can also be used. The solid-state pulse laser light source can emit laser light with a wavelength of 193 nm (various wavelengths other than this) and a pulse width of about 1 ns at a frequency of about 1 to 2 MHz.

In the present embodiment, a power source unit 42 is connected to the light source 2. The main control system 40 supplies a light emission trigger pulse TP instructing the pulse emission timing and the light amount (pulse energy) to the power supply unit 42. In synchronization with the light emission trigger pulse TP, the power supply unit 42 causes the light source 2 to emit pulses at the instructed timing and light quantity.
Illumination light IL made up of pulse laser light having a rectangular cross-sectional shape emitted from the light source 2 and a substantially parallel light beam is a beam expander 4 made up of a pair of lenses, and a polarization control optical system 6 that controls the polarization state of the illumination light IL. And an array of a plurality of minute pixels 12 (an optical element having a member corresponding to the cell portion 34 in FIG. 2) of the main body 10 having the base member 11 of the spatial light modulator 9 for the illumination system via the mirror 8A. Is incident on. The polarization control optical system 6 includes, for example, a half-wave plate that rotates the polarization direction of the illumination light IL, a quarter-wave plate for converting the illumination light IL into circularly polarized light, and the illumination light IL that is randomly polarized (non-polarized light). This is an optical system in which a wedge-shaped birefringent prism or the like for conversion into (1) can be installed interchangeably.

  The spatial light modulator 9 has substantially the same configuration as the spatial light modulator 28, the main body 10 of the spatial light modulator 9 corresponds to the main body 30, and the modulation control unit 49 corresponds to the modulation control unit 48. . The pixels 12 (cell portions) of the spatial light modulator 9 are arranged in a two-dimensional array on a plane (array plane) inclined in the θx direction with respect to the XY plane, and control the phase of the input illumination light IL. And reflect. By controlling the phase distribution of the reflected illumination light IL in this way, the pupil plane of the illumination optical system ILS is used, for example, when switching diffractive optical elements (DOE) having various characteristics. Can be controlled to an arbitrary distribution such as a circular shape for normal illumination, an annular shape for annular illumination, and a dipole or quadrupolar shape for multipolar illumination.

  For example, before the exposure of one lot of wafers is started, the illumination system control unit 41 sends a plurality of pixels 12 corresponding to each illumination condition to the modulation control unit 49 of the spatial light modulator 9 under the control of the main control system 40. The phase distribution information of the illumination light IL set by the array is supplied. In response to this, the modulation controller 49 controls each pixel 12 of the spatial light modulator 9 to the first state (phase 0) or the second state (phase π). Each pixel 12 may be set to a state in which the phase of the reflected light is changed in a phase other than the first or second state.

  The illumination light IL reflected by the spatial light modulator 9 is guided to the incident surface of the microlens array 16 along the Y axis (optical axis AXI) via the relay optical system 14 including the lenses 14a and 14b and the mirror 8B. . The illumination light IL incident on the microlens array 16 is two-dimensionally divided (wavefront division) by a large number of minute lens elements constituting the microlens array 16, and the illumination optical system that is the rear focal plane of each lens element. A secondary light source (surface light source) is formed on the pupil surface of the ILS (hereinafter referred to as illumination pupil surface IPP). Note that a fly-eye lens or the like can be used instead of the microlens array 16.

  The illumination light IL from the secondary light source formed on the illumination pupil plane IPP is incident on the half mirror 24 via the first relay lens 18A, the field stop 20, the second relay lens 18B, and the condenser optical system 22, Illumination light IL reflected by the mirror 24 in the + Z direction is incident on an irradiated surface (a surface on which a designed transfer pattern is arranged) parallel to the XY plane. Reflecting surface 37a (see FIG. 2) of a large number of pixels 32 (optical elements having cell portions 34 in FIG. 2) arranged in a two-dimensional array of spatial light modulators 28 on the irradiated surface or in the vicinity thereof. ) Is arranged. The illumination optical system ILS includes the optical members from the beam expander 4 to the condenser optical system 22. Note that a quarter-wave plate may be disposed between the polarization beam splitter and the spatial light modulator 28 with the half mirror 24 as a polarization beam splitter and the polarization state of the illumination light IL input thereto as S polarization. . Thereby, almost all of the illumination light IL reflected by the spatial light modulator 28 passes through the polarization beam splitter and travels toward the projection optical system PL, so that the utilization efficiency of the illumination light IL can be improved.

  As an example, the illumination light IL from the illumination optical system ILS illuminates a rectangular illumination area 26A elongated in the X direction on the array of the many pixels 32 of the spatial light modulator 28 with a substantially uniform illuminance distribution. The illumination optical system ILS, the half mirror 24, and the main body 30 of the spatial light modulator 28 are supported by a frame (not shown). As an example, the exposure pattern control unit 43 under the control of the main control system 40 is set in the modulation control unit 48 of the spatial light modulator 28 by the array of pixels 32 every time the illumination light IL having a predetermined number of pulses is emitted. Information on the phase distribution of the light IL is supplied. In response to this, the modulation controller 48 controls each pixel 32 of the spatial light modulator 28 to the first state (phase 0) or the second state (phase π). An aerial image corresponding to the phase distribution is formed on the surface of the wafer W.

  The illumination light IL reflected by the array of a large number of mirror elements 30 in the illumination area 26A of the spatial light modulator 28 enters the projection optical system PL via the half mirror 24. Projection optical system PL having optical axis AX supported by a column (not shown) is a double-sided telecentric reduction projection optical system. The projection optical system PL converts a reduced image of the aerial image corresponding to the phase distribution of the illumination light IL set by the spatial light modulator 28 into an exposure area 26B (an illumination area 26A and an illumination area 26A) in one shot area of the wafer W. To a region conjugate to The projection magnification β of the projection optical system PL is, for example, about 1/10 to 1/100, and the resolution (half pitch or line width) is, for example, about the width of the image of the pixel 32 of the spatial light modulator 28. For example, if the width of the pixel 32 is about several μm and the projection magnification β of the projection optical system PL is about 1/100, the resolution of the projection optical system PL is about several tens of nm.

  The wafer W (substrate) includes, for example, a surface of a circular flat base material such as silicon or SOI (silicon on insulator) applied with a photoresist (photosensitive material) with a thickness of about several tens to 200 nm. . Further, when the exposure apparatus EX is of an immersion type, for example, as disclosed in US Patent Application Publication No. 2007/242247, a space between the optical member at the tip of the projection optical system PL and the wafer W is disclosed. A local liquid immersion device for supplying and recovering a liquid (for example, pure water) that transmits the illumination light IL is provided. In the case of the immersion type, the resolution can be further increased.

  In FIG. 12, wafer W is sucked and held on the upper surface of wafer stage WST via a wafer holder (not shown), and wafer stage WST performs step movement in the X direction and Y direction on a guide surface (not shown) and Y Move at a constant speed in the direction. The position of wafer stage WST in the X and Y directions, the rotation angle in the θz direction, and the like are formed by laser interferometer 45, and this measurement information is supplied to stage control system 44. Stage control system 44 controls the position and speed of wafer stage WST via drive system 46 such as a linear motor based on control information from main control system 40 and measurement information from laser interferometer 45. In order to perform alignment of the wafer W, an alignment system (not shown) for detecting the position of the alignment mark on the wafer W is also provided.

When the wafer W is exposed, after the wafer W is aligned, the illumination condition of the illumination optical system ILS is set using the spatial light modulator 9. Then, in order to perform exposure on the shot areas arranged in a line in the Y direction on the surface of the wafer W, the wafer W is positioned at the scanning start position. Thereafter, scanning of the wafer W at a constant speed in the + Y direction is started.
Next, the main control system 40 corresponds to the aerial image formed in the exposure area 26B in the modulation control section 48 via the exposure pattern control section 43 according to the relative position of the exposure area 26B of the wafer W to the shot area. Information on the phase distribution of the illumination light IL on the reflecting surface of the spatial light modulator 28 is supplied, and a light emission trigger pulse TP is supplied to the power supply unit 42. As a result, a target aerial image is sequentially exposed in the exposure area 26B according to the position in the Y direction. By repeating this operation until the shot area crosses the exposure area 26B, the entire aerial image (circuit pattern) is exposed in the shot area.

  Thereafter, in order to expose a shot area adjacent to the shot area of the wafer W, the main control system 40 sends the illumination light IL to the modulation controller 48 via the exposure pattern controller 43 while scanning the wafer W in the same direction. And the light emission trigger pulse TP is supplied to the power supply unit 42. In this manner, exposure can be continuously performed from the first shot area to the next shot area. When shifting to exposure of a row including shot regions adjacent to the wafer W in the X direction, the wafer stage WST is driven to move the wafer W stepwise in the X direction (non-scanning direction orthogonal to the scanning direction). . Then, the scanning direction of the wafer W with respect to the exposure region 26B is set to the opposite −Y direction, and the phase distribution of the illumination light IL is reversed from the main control system 40 to the modulation control unit 48 via the exposure pattern control unit 43. By supplying information and supplying the light emission trigger pulse TP to the power supply unit 42, it is possible to continuously expose a series of shot regions in adjacent columns. In this exposure, it is also possible to expose different aerial images to a plurality of shot areas. Each shot area may be exposed by a plurality of scans. Thereafter, the photoresist on the wafer W is developed, so that a resist pattern is formed in each shot area of the wafer W.

The effects and the like of this embodiment are as follows.
(1) In the first aspect, the exposure apparatus EX that exposes the wafer W of the present embodiment with the illumination light IL includes the spatial light modulator 28 and the plurality of cell units 34 (pixels 32) of the spatial light modulator 28. An illumination optical system ILS that irradiates the array with illumination light IL, a projection optical system PL that guides illumination light from the plurality of cell units 34 to the wafer W and projects a pattern onto the wafer W, and a pattern that is exposed to the wafer W In order to control, an exposure pattern control unit 43 that controls the phase of illumination light passing through the plurality of cell units 34 of the spatial light modulator 28 is provided.

  According to the exposure apparatus EX of the first aspect, since the spatial light modulator 28 is provided, an arbitrary pattern can be exposed on the wafer W by a maskless method. In the case of performing exposure in the maskless manner as described above, for example, U.S. Pat. No. 6,900,915 and U.S. Pat. No. 7,095,546 are used instead of the spatial light modulator 9 in the illumination optical system ILS. Or a spatial light modulator having a large number of micromirrors each having a variable tilt angle about two orthogonal axes, as disclosed in US Pat. Appln. No. 2005/0095749. You can also. Further, instead of the spatial light modulator 9, a plurality of diffractive optical elements (DOE) may be switched and used.

  (2) In addition, the cell portion 34 (pixel 32) of the spatial light modulator 28 is provided in a rectangular region whose longitudinal direction is the X direction, and the wafer W is in the Y direction orthogonal to the X direction on the image plane of the projection optical system PL. The exposure pattern control unit 43 includes a pattern (phase distribution) formed by a plurality of pixels 32 according to the movement of the wafer W by the wafer stage WST. Is moved in the Y direction. Thereby, the entire surface of the wafer W can be efficiently exposed by a maskless method.

Instead of the spatial light modulator 28, the spatial light modulators 28A, 28B of the modified example of the first embodiment can be used.
(3) Further, in the second aspect, the exposure apparatus EX that exposes the wafer W with the illumination light IL through the mask pattern of the present embodiment has the spatial light modulator 9, and the spatial light modulation with the illumination light IL. In order to control the illumination optical system ILS that illuminates the mask pattern via the device 9 and the distribution of the incident angles of the illumination light IL that illuminates the mask pattern (light quantity distribution on the illumination pupil plane IPP), the spatial light modulation And an illumination system control unit 41 that controls the phase of the illumination light IL that passes through the plurality of cell units (pixels 12) of the device 9.

  According to the exposure apparatus EX of the second aspect, since the spatial light modulator 9 is used in the illumination optical system ILS, the mask pattern can be obtained only by controlling the phase distribution of the illumination light IL by the spatial light modulator 9. The distribution of the incident angles of the illumination light IL that illuminates the light (the light amount distribution on the illumination pupil plane IPP) can be controlled to an arbitrary distribution. In the exposure apparatus EX according to the second aspect, instead of the spatial light modulator 28 for setting a mask pattern (phase pattern), a reticle stage that can reciprocate at least in the Y direction, and a reticle stage are mounted. Thus, a reticle on which a transfer pattern is formed may be used.

Instead of the spatial light modulator 9, the spatial light modulators 28A and 28B according to the modification of the first embodiment can be used.
Next, in the present embodiment, the following modifications are possible. First, in the present embodiment, the wafer W is continuously moved by scanning and exposing the wafer W. In addition, each shot area of the wafer W is divided into a plurality of partial areas in the Y direction, and when the partial area in the exposure area 26B of the projection optical system PL reaches, the illumination light IL is emitted by a predetermined number of pulses. The partial area may be exposed with the reflected light from the array of pixels 32 of the spatial light modulator 28. Thereafter, the wafer W is moved stepwise in the Y direction, and after the next partial area reaches the exposure area 26B, the partial area is similarly exposed. This method is substantially a step-and-repeat method, but different patterns are exposed to adjacent partial areas.

  In the above embodiment, the telecentric projection optical system PL is used on the object side and the image plane side. In addition, a non-telecentric projection optical system PLA can also be used on the object side, as shown by the exposure apparatus EXA of the modified example of FIG. In FIG. 13, the illumination optical system ILSA of the exposure apparatus EXA includes a main body ILSB including optical members from the light source 2 to the first relay lens 18A in FIG. 12, and a field of view where illumination light IL from the main body ILSB is sequentially irradiated. A diaphragm 20, a mirror 8C, a second relay lens 18B, a condenser optical system 22, and a mirror 8D are provided. The illumination optical system ILSA irradiates the array of pixels 32 (cell part 34) of the spatial light modulator 28 arranged on the object plane of the projection optical system PLA with the illumination light IL at an incident angle β in the θx direction. The projection optical system PLA forms a predetermined aerial image on the surface of the wafer W by the illumination light IL reflected obliquely from the array of pixels 32. The incident angle β is, for example, several deg (°) to several tens deg. The expression (2) is set so that the phase difference between the illumination light reflected by the pixel 32 in the first state and the illumination light reflected by the pixel 32 in the second state becomes 180 ° according to the incident angle β. ) Or the value of the depth d of the second liquid Lqb in the cell part 34 of the formula (3) may be adjusted. Other configurations and operations are the same as those in the above embodiment.

  Further, instead of the microlens array 16 as the wavefront division type integrator of FIG. 12, a rod type integrator as an inner surface reflection type optical integrator may be used. In this case, in FIG. 12, a condensing optical system is added to the spatial light modulator 9 side of the relay optical system 14 to form a conjugate surface of the reflective surface of the spatial light modulator 9, and the incident end is near the conjugate surface. A rod-type integrator may be arranged so that is positioned.

In addition, a relay optical system for forming an image of the illumination field stop disposed on the exit end face of the rod-type integrator or in the vicinity of the exit end face on the reflection surface of the spatial light modulator 9 is disposed. In this configuration, the secondary light source is formed on the pupil plane of the relay optical system 14 and the condensing optical system (a virtual image of the secondary light source is formed near the incident end of the rod integrator).
Further, when an electronic device (or micro device) is manufactured, as shown in FIG. 14, the electronic device performs step 221 for performing function / performance design of the electronic device, and forms mask pattern data based on this design step. In step 222, which is stored in the main control system of the exposure apparatuses EX, EXA, step 223, in which a substrate (wafer) which is the base material of the device is manufactured and resist is applied, and the exposure apparatuses EX, EXA (or exposure method) described above A step of exposing a spatial image of a phase distribution generated by the spatial light modulator 28 (or mask pattern) onto a substrate (sensitive substrate), a step of developing the exposed substrate, a heating (curing) of the developed substrate, an etching step, etc. Substrate processing step 224 including, device assembly step (dicing process, bonding process, package Including processed processes such extent) 225, and an inspection step 226, and the like.

This device manufacturing method includes a step of exposing the wafer W using the exposure apparatus of the above-described embodiment, and a step of processing the exposed wafer W (step 224). Therefore, an electronic device can be efficiently manufactured with high accuracy.
Further, the present invention is not limited to the application to the manufacturing process of a semiconductor device. For example, a manufacturing process such as a liquid crystal display element and a plasma display, an imaging element (CMOS type, CCD, etc.), a micromachine, a MEMS ( (Microelectromechanical systems), thin film magnetic heads, and various devices (electronic devices) such as DNA chips can be widely applied.

  In addition, the spatial light modulators 28, 28A, 28B and the like of the above-described embodiment and its modifications can be used for a display device other than the exposure device or an optical device such as a projector. This optical device includes a spatial light modulator 28 (or 28A, 28B, etc.) and an illumination system (first optical system) that irradiates illumination light to a plurality of cell units 34 (pixels 32) of the spatial light modulator 28. And an imaging optical system (second optical system) for guiding the light modulated by the cell portions 34 (pixels 32) to the image plane (the surface of the object). According to this optical device, for example, high resolution can be obtained.

  In addition, this invention is not limited to the above-mentioned embodiment, A various structure can be taken in the range which does not deviate from the summary of this invention.

  EX, EXA ... exposure apparatus, ILS, ILSA ... illumination optical system, PL, PLA ... projection optical system, W ... wafer, Lqa ... first liquid, Lqb ... second liquid, 28 ... spatial light modulator, 30 ... main body 32 ... Pixel, 34 ... Cell part, 36 ... Transparent electrode, 37 ... Bottom electrode, 38 ... Projection electrode part, 39A-39D ... Side wall electrode, 48 ... Modulation control part, 54 ... SRAM

Claims (17)

A spatial light modulator that modulates light incident on the array surface,
A cell part having a partition part along a first direction crossing the arrangement surface;
First and second liquids having different refractive indices and dielectric constants contained in the cell part; and
A first electrode provided on at least a part of the window part into which the light of the cell part is incident;
A second electrode provided on at least a part of a bottom surface and a side surface of the cell portion,
An optical path length of light passing through the cell unit by controlling a thickness ratio of the first and second liquids in the cell unit by a voltage applied to the first and second electrodes of the cell unit. A spatial light modulator characterized by controlling the above.   The spatial light modulator according to claim 1, wherein the first electrode is a transparent electrode provided on an entire surface of the window portion of the cell portion.   The spatial light modulator according to claim 1, wherein the second electrode is provided on a part of a bottom surface of the cell portion.   The spatial light modulator according to claim 3, wherein the second electrode also serves as a reflection unit that reflects light incident on the cell unit.   The spatial light modulator according to claim 1, wherein the second electrode is provided on at least a part of a side surface of the cell portion. A third electrode provided on at least a part of the side surface of the cell portion;
5. The spatial light modulator according to claim 3, wherein a voltage for controlling a contact angle of the first and second liquids with respect to a side surface of the cell portion is applied to the third electrode. The cell part has four sides,
The spatial light modulator according to claim 6, wherein the third electrode includes four electrodes provided on the four side surfaces.   The spatial light modulator according to claim 3, 4, 6, or 7, wherein the second electrode has a convex portion that gradually decreases in cross-sectional area toward the window portion of the cell portion.   The spatial light modulator according to claim 8, wherein the convex portion of the second electrode is a pyramid shape or a roof shape.   The first and second electrodes have a first set of voltages that change the phase of light passing through the cell portion by a first phase, or the phase of light passing through the cell portion as the first phase. 10. The spatial light modulator according to claim 1, wherein one of a plurality of sets of voltages including a second set of voltages that are changed by a second phase different by 180 ° is given. 11. A plurality of the cell portions arranged in a two-dimensional or one-dimensional array along the arrangement surface;
The first and second electrodes provided corresponding to the plurality of cell portions, respectively, and the first and second liquids;
A control unit for controlling the phase of light passing through the cell unit by controlling the voltages of the first and second electrodes corresponding to each other independently of the plurality of cell units;
The spatial light modulator according to claim 1, wherein the spatial light modulator is provided. A spatial light modulator that modulates light incident on the array surface,
A cell part having a partition part along a first direction crossing the arrangement surface;
First and second liquids having different transmittances and dielectric constants contained in the cell part; and
A first electrode provided on at least a part of the window part into which the light of the cell part is incident;
A second electrode provided on at least a part of a bottom surface and a side surface of the cell portion,
The transmittance of light passing through the cell unit by controlling the ratio of the thicknesses of the first and second liquids in the cell unit by the voltage applied to the first and second electrodes of the cell unit. A spatial light modulator characterized by controlling the above.   The spatial light modulator according to claim 1, wherein the partition wall is formed in a frame shape. The spatial light modulator according to any one of claims 1 to 13,
A first optical system for irradiating illumination light to the cell portion of the spatial light modulator;
An optical device comprising: a second optical system that guides light from the cell unit to an object. In an exposure apparatus that exposes a substrate with exposure light,
A spatial light modulator according to claim 11;
An illumination optical system for irradiating the exposure light to the array of the plurality of cell portions of the spatial light modulator;
A projection optical system that guides light from the plurality of cell portions onto the substrate and projects a pattern on the substrate;
An exposure control device for controlling a phase pattern of light from the plurality of cell units of the spatial light modulator in order to control a pattern exposed to the substrate;
An exposure apparatus comprising: In an exposure apparatus that exposes a substrate with exposure light through a mask,
An illumination optical system comprising the spatial light modulator according to claim 11 and illuminating the mask with the exposure light via the spatial light modulator;
An illumination control device that controls phase patterns of light from the plurality of cell units of the spatial light modulator in order to control a distribution of incident angles of the exposure light that illuminates the mask;
An exposure apparatus comprising: Forming a pattern of a photosensitive layer on a substrate using the exposure apparatus according to claim 15 or 16,
Processing the substrate on which the pattern is formed;
A device manufacturing method including:

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