Exposure apparatus

Abstract

To provide a technique that allows, in an exposure apparatus, respective appropriate measurement of a light amount of diffracted light with a low light level and a light amount of diffracted light with a high light level.SOLUTION: An exposure apparatus 100 comprises a diffractive spatial light modulator 41 that modulates intensity of laser light by diffracting laser light emitted from a laser oscillator 52 serving as a light source, a projection optical system 43 that forms an image of diffracted light diffracted by the spatial light modulator 41, a light amount detector 87 that detects the diffracted light having passed through the projection optical system 43, and a light reduction unit 89 capable of reducing light of the diffracted light incident on the light amount detector 87. A main scanning mechanism 25 switches a position of the light reduction unit 89 relative to the diffracted light between a position on an optical path of the diffracted light and a position deviated from the optical path.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The subject matter disclosed herein relates to an exposure apparatus. [Background technology]

[0002] Exposure apparatuses (direct imaging apparatuses) that perform direct imaging by irradiating light are known as a method for forming patterns on substrates such as semiconductor wafers and glass substrates. In this type of exposure apparatus, a substrate with a photosensitive layer such as resist formed thereon is held on a stage, which is moved in the main scanning direction. A predetermined pattern is then drawn on the photosensitive layer by emitting pattern light from an optical head according to the position of the stage in the main scanning direction. A spatial light modulator (SLM) is used to form pattern light corresponding to the pattern. Spatial light modulators such as Grating Light Valve (GLV, a registered trademark of Silicon Light Machines, Inc.) or Digital Mirror Device (DMD) are capable of on / off control of thousands of pixel beams.

[0003] An exposure apparatus includes a light source, an illumination optical system, a spatial light modulator, a projection optical system, and a controller that controls the spatial light modulator. The uniformity of the exposure line width depends on the uniformity of the light intensity of the exposure beam and the uniformity of the exposure beam size. The uniformity of the light intensity on the exposure surface is distributed according to the reflectance of the illumination system and the spatial light modulator. The spatial light modulator is an element whose reflectance can be controlled by finely adjusting the voltage applied to each channel, allowing for precise adjustment of the light intensity distribution on the exposure surface. Therefore, the uniformity of the light intensity has been improved by finely adjusting the voltage of each channel according to the results of measuring the uniformity of the light intensity on the exposure surface (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-133751 Summary of the Invention [Problem to be solved by the invention]

[0005] To expose a circuit pattern, it is necessary to adjust the light intensity in at least two ways: the bright side (ON) that exposes the object to light, and the dark side (OFF) that does not expose the object to light. Ideally, the dark side (OFF) is the state where the light intensity of each channel is the darkest, but depending on the characteristics of the resist to be exposed, it may be preferable to adjust the light intensity of all channels to the same level, even if the light intensity of each channel is slightly higher.

[0006] When adjusting the light intensity on the bright side, an intensity distribution (waveform) with sufficient height difference for each channel can be obtained by adjusting the gain so that the upper limit of the incident tolerance range of the photodiode, which is the light intensity detector, is the maximum light intensity. Therefore, when adjusting the light intensity on the bright side, the variation between channels can be reduced by adjusting the voltage applied to the GLV based on the obtained intensity distribution.

[0007] On the other hand, when adjusting the light intensity on the dark side, the light may be so dim that no light enters the photodiode, meaning that the light is buried in the noise characteristics of the photodiode itself. Therefore, it is possible to use a photodiode with a detection range adjusted to the low light level side, but if such a light detector detects high levels of light, the output may become saturated, making it difficult to accurately read the light intensity. Furthermore, if light exceeding the set maximum input intensity enters the light receiving element, the light receiving element may be damaged.

[0008] An object of the present invention is to provide a technique that can appropriately measure the amount of low-intensity diffracted light and the amount of high-intensity diffracted light in an exposure apparatus. [Means for solving the problem]

[0009] In order to solve the above problem, a first aspect is an exposure apparatus that exposes a surface of an object, and includes a light source, a diffractive spatial light modulator that modulates the intensity of light by diffracting the light emitted from the light source, an optical system that forms an image of the diffracted light diffracted by the spatial light modulator, a light intensity detector that detects the amount of the diffracted light that has passed through the optical system, an attenuation unit that can attenuate the diffracted light that enters the light intensity detector, and a moving unit that switches the position of the attenuation unit with respect to the diffracted light between a position on the optical path of the diffracted light and a position away from the optical path.

[0010] A second aspect is the exposure apparatus of the first aspect, wherein the light attenuation section has a light attenuation filter or a polarizing plate.

[0011] A third aspect is an exposure apparatus according to the first or second aspect, further comprising a stage that supports a substrate, wherein the attenuation unit and the light intensity detector are fixed to the stage, and the moving unit moves the stage.

[0012] A fourth aspect is the exposure apparatus of the first or second aspect, wherein the moving section moves the attenuation section relative to the optical system that is fixed in a fixed position.

[0013] A fifth aspect is the exposure apparatus of the first or second aspect, further comprising an aperture having a plurality of openings through which the diffracted light can pass, and the light attenuation unit is located in one of the plurality of openings.

[0014] A sixth aspect is the exposure apparatus of the first or second aspect, wherein the attenuation section is capable of attenuating the diffracted light in a plurality of stages. [Effects of the Invention]

[0015] According to the exposure apparatuses of the first to sixth aspects, it is possible to attenuate high-intensity diffracted light, so that even a light detector whose detection range is set to the low-intensity side can properly measure the intensity of high-intensity diffracted light. This makes it possible to properly measure the intensity of low-intensity diffracted light and the intensity of high-intensity diffracted light using a common light detector.

[0016] According to the exposure apparatus of the fourth aspect, there is no need to move the optical system, so there is no need for a large-scale drive mechanism. Furthermore, by not moving the optical system, it is possible to prevent the optical system from becoming misaligned.

[0017] According to the exposure apparatus of the sixth aspect, the degree of light attenuation can be changed in multiple stages according to the amount of diffracted light, so that the amount of light can be measured appropriately. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram showing an exposure apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram showing a schematic configuration of an exposure unit. [Figure 3] FIG. 1 is a cross-sectional view showing a spatial light modulator. [Figure 4] FIG. 2 is a diagram showing an observation unit 8 of the exposure apparatus shown in FIG. [Figure 5] 2 is a block diagram showing the configuration of a control unit shown in FIG. 1. FIG. [Figure 6] 10A and 10B are diagrams illustrating a method for determining an appropriate driving range. [Figure 7] FIG. 10 is a diagram showing the light intensity distribution when the light intensity of all channels is minimized. [Figure 8] FIG. 2 is a diagram schematically illustrating the configuration of a light quantity measuring unit in the observation unit. [Figure 9] FIG. 10 is a diagram showing a light quantity measuring unit of an exposure apparatus according to a second embodiment. [Figure 10] FIG. 11 is a diagram showing a light quantity measuring unit of an exposure apparatus according to a third embodiment. [Figure 11] 10A and 10B are diagrams illustrating an aperture and a light-reducing unit according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the components described in the embodiment are merely examples and are not intended to limit the scope of the present invention. In the drawings, the dimensions and numbers of each part may be exaggerated or simplified as necessary to facilitate understanding.

[0020] 1. First embodiment 1 is a diagram showing an exposure apparatus 100 according to an embodiment. The exposure apparatus 100 is an apparatus that draws a pattern by irradiating light onto the upper surface of a substrate W on which a layer of photosensitive material such as resist has been formed. The substrate W is, for example, a semiconductor substrate, a printed circuit board, a substrate for a color filter, a glass substrate for a flat panel display used in a liquid crystal display device or a plasma display device, or a substrate for an optical disc.

[0021] The exposure apparatus 100 includes a main body frame 101. Inside the main body frame 101, the exposure apparatus 100 has a processing area 102 and a transfer area 103. In the processing area 102, a stage 10, a stage moving mechanism 2, and an exposure unit U are arranged. In the transfer area 103, a transport device 7 that loads and unloads a substrate W is arranged. The exposure apparatus 100 also includes a control unit 9.

[0022] A cassette mounting part 104 for mounting a cassette C is disposed adjacent to the transfer area 103. The transport device 7 takes out an unprocessed substrate W stored in the cassette C and carries it into the processing area 102, and also carries a processed substrate W out of the processing area 102 and stores it in the cassette C. The transfer of the cassette C to and from the cassette mounting part 104 is performed by an external transport device (not shown). The transfer of the substrate W by the transport device 7 is performed under the control of the control unit 9.

[0023] The stage 10 has a rectangular shape when viewed from above. The stage 10 has an upper surface that holds the substrate W. The substrate W is placed in a horizontal position on the upper surface of the stage 10. A plurality of suction holes are formed in the upper surface of the stage 10. The stage 10 can fix the substrate W to the upper surface of the stage 10 by applying a negative pressure (suction pressure) to the suction holes. Note that a chuck that grips the periphery of the substrate W may be provided on the upper surface of the stage 10, and the substrate W may be fixed by the chuck.

[0024] The stage movement mechanism 2 is a mechanism that moves the stage 10 in the Y direction, which is the main scanning direction, the X direction, which is the sub-scanning direction, and in a rotation direction (θ-axis direction) about a rotation axis A that extends in the Z direction. The stage movement mechanism 2 has a support plate 22, a sub-scanning mechanism 23, a base plate 24, a main scanning mechanism 25, and a rotation mechanism 27.

[0025] The support plate 22 rotatably supports the stage 10. The base plate 24 supports the support plate 22 and the sub-scanning mechanism 23. The sub-scanning mechanism 23 moves the support plate 22 and the stage 10 in the X direction relative to the base plate 24. The main scanning mechanism 25 moves the support plate 22 and the stage 10 together with the base plate 24 in the Y direction. The rotation mechanism 27 rotates the stage 10 around a rotation axis A relative to the support plate 22. The sub-scanning mechanism 23, the main scanning mechanism 25, and the rotation mechanism 27 are configured by a ball screw mechanism equipped with a rotary motor and a ball screw, a linear motor mechanism, or the like. The operations of the sub-scanning mechanism 23, the main scanning mechanism 25, and the rotation mechanism 27 are controlled by the control unit 9.

[0026] 2 is a diagram showing a schematic configuration of the exposure unit U. The exposure unit U has a plurality of (for example, five) exposure heads 4 arranged in the X direction. The exposure heads 4 are equipped with a spatial light modulator 41 and a projection optical system 43. The spatial light modulator 41 spatially modulates laser light based on drawing data corresponding to a drawing pattern. The projection optical system 43 reduces the laser light (diffracted light, described later) spatially modulated by the spatial light modulator 41 and emits it toward the stage 10.

[0027] The exposure unit U has a plurality of (e.g., five) light irradiation sections 5. The exposure unit U has one light irradiation section 5 for one exposure head 4. Since the plurality of light irradiation sections 5 all have the same configuration, one light irradiation section 5 will be described below.

[0028] The light irradiation section 5 of the exposure unit U has a laser driver 51, a laser oscillator 52, and an illumination optical system 53. The laser driver 51 is a device that drives the laser oscillator 52, which is a light source. The illumination optical system 53 is a device that shapes the laser light emitted from the laser oscillator 52 and projects it onto the spatial light modulator 41 of the exposure head 4.

[0029] 2, the projection optical system 43 forms an image on an exposure surface ES of the laser light spatially modulated by the spatial light modulator 41. The exposure surface ES is, for example, the surface of the substrate W (or the photosensitive layer W1) that is the object.

[0030] FIG. 3 is a cross-sectional view showing a spatial light modulator 41. Specifically, the spatial light modulator 41 is a GLV, which is a type of diffractive modulation element. The spatial light modulator 41 has a bottom electrode 61, multiple fixed ribbons 63, and multiple movable ribbons 65. The bottom electrode 61 has, for example, a flat plate shape. The fixed ribbons 63 and the movable ribbons 65 are alternately arranged in one direction (X direction) on the bottom electrode 61. The lower surface of each fixed ribbon 63 and the lower surface of each movable ribbon 65 face the upper surface of the bottom electrode 61, respectively. The upper surface of the fixed ribbon 63 is a fixed reflective surface 63S, and the upper surface of the movable ribbon 65 is a movable reflective surface 65S. The fixed reflective surface 63S and the movable reflective surface 65S are finished to be flat. The multiple fixed reflective surfaces 63S and the multiple movable reflective surfaces 65S form a light-collecting surface 41S of the spatial light modulator 41.

[0031] The fixed reflecting surface 63S is fixed at a position a predetermined distance away from the bottom electrode 61. The movable reflecting surface 65S is provided so as to be movable in a direction toward or away from the bottom electrode 61 according to an applied voltage (driving voltage). That is, the movable reflecting surface 65S is movable in a direction perpendicular to the movable reflecting surface 65S relative to the fixed reflecting surface 63S.

[0032] The amount of displacement of the movable reflecting surface 65S is adjusted according to the magnitude of the potential difference generated by the drive voltage between the movable ribbon 65 and the bottom electrode 61. For example, as shown on the left side of Figure 3, when the height difference d between the fixed reflecting surface 63S and the movable reflecting surface 65S is zero, the light reflected by the fixed reflecting surface 63S and the light reflected by the movable reflecting surface 65S are in phase, and therefore these lights are emitted from the spatial light modulator 41 as specular reflected light Lr (zeroth-order diffracted light).

[0033] When the wavelength of the incident light Li is λ, if the optical path difference (= 2d) between the light reflected by the fixed reflecting surface 63S and the light reflected by the movable reflecting surface 65S is an integer multiple of the wavelength λ (= n × λ (n is an integer greater than or equal to zero)), the light reflected by the fixed reflecting surface 63S and the light reflected by the movable reflecting surface 65S will be in phase. That is, the specular reflected light Lr (zeroth-order diffracted light) is emitted from the spatial light modulator 41.

[0034] 3, when the optical path difference (=2d) between the light reflected by the fixed reflecting surface 63S and the light reflected by the movable reflecting surface 65S is an odd multiple of the half-wavelength λ / 2, the light reflected by the fixed reflecting surface 63S and the light reflected by the movable reflecting surface 65S are in opposite phase to each other and cancel each other out. Therefore, the spatial light modulator 41 does not emit reflected light in the vertical direction, but emits light in an oblique direction, i.e., ±1st-order or higher diffracted light (scattered light Ld).

[0035] 3, when the optical path difference (=2d) between the light reflected by the fixed reflecting surface 63S and the light reflected by the movable reflecting surface 65S is different from the wavelength λ and different from the half-wavelength λ / 2, a portion of the incident light Li is emitted as specularly reflected light Lr, and the remainder is emitted obliquely as ±1st-order or higher diffracted light (scattered light Ld). That is, depending on the magnitude of the height difference d, specularly reflected light Lr having an intensity weaker than that of the incident light Li is emitted from the spatial light modulator 41. In this way, in the spatial light modulator 41, the intensity of the specularly reflected light Lr (or the intensity of the scattered light Ld) can be adjusted by changing the drive voltage.

[0036] The exposure apparatus 100 performs drawing by irradiating the substrate W with zero-order diffracted light emitted from the spatial light modulator 41. Furthermore, ±1st-order and higher diffracted light are blocked by an aperture 43a (see FIG. 2) provided in the projection optical system 43. In other words, ±1st-order and higher diffracted light are not emitted from the projection optical system 43 when performing exposure. In the following explanation, the state shown on the left or right side of FIG. 3 will be referred to as the "on state," and the state shown in the center of FIG. 3 will be referred to as the "off state." The on state is a state in which light is irradiated from the spatial light modulator 41 toward the substrate W, and the off state is a state in which the light is not irradiated. These states are distinguished by the magnitude of the drive voltage applied to the movable ribbons 65.

[0037] The drive voltage can be set individually for each movable ribbon 65. Therefore, an on state and an off state can be produced for each ribbon pair consisting of one movable ribbon 65 and the adjacent fixed ribbon 63. In the following explanation, the smallest unit for controlling on / off, consisting of a pair of ribbons, is called a "channel."

[0038] In the exposure head 4, the spatial light modulator 41 is disposed so that the normal to its condensing surface 41S is inclined with respect to the optical axis. The line beam LB that has passed through the illumination optical system 53 is irradiated onto the condensing surface 41S of the spatial light modulator 41. The state of each channel in the spatial light modulator 41 is then switched by the control unit 9 in accordance with the drawing data, thereby modulating the line beam LB that has entered the spatial light modulator 41. One pixel represented by the drawing data corresponds to one or several channels.

[0039] 4 is a diagram showing the observation unit 8 of the exposure apparatus 100 shown in FIG. The observation unit 8 is arranged on the side of the stage 10. The observation unit 8 is a device for receiving diffracted light emitted from the exposure head 4 and observing the diffracted light. The observation unit 8 may be made into a unit that can be attached to and detached from the stage 10.

[0040] The observation unit 8 has a dummy substrate 81, a magnifying optical system 82, an observation camera 83, a case 84, a support frame 85, a beam splitter 86, and a light intensity detector 87. The dummy substrate 81 is a light-transmitting substrate formed into a flat plate shape from, for example, quartz glass. The dummy substrate 81 is placed on top of the case 84.

[0041] A magnifying optical system 82 is disposed below the dummy substrate 81. The magnifying optical system 82 is an optical system for magnifying incident light. An observation camera 83 is disposed below the magnifying optical system 82 via a beam splitter 86. The observation camera 83 has a two-dimensional image sensor such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The observation camera 83 captures an image of diffracted light incident from the dummy substrate 81 via the beam splitter 86. The dummy substrate 81 and the observation camera 83 are each attached to a case 84 and integrated together. The focal position of the optical system of the observation camera 83 is adjusted to the upper surface 81S of the dummy substrate 81.

[0042] The case 84 is supported by a support frame 85 erected on the support plate 22 so that it can move up and down freely. The movement of the case 84 in the vertical direction can be controlled by the control unit 9. In this way, the observation unit 8 moves integrally with the stage 10 in the horizontal directions (X direction and Y direction), but can move independently of the stage 10 in the vertical direction (Z direction).

[0043] A portion of the diffracted light that passes through the dummy substrate 81 and enters the observation unit 8 has its path changed by the beam splitter 86 and enters a light intensity detector 87 provided in the case 84. A light collecting optical system (not shown) is provided between the beam splitter 86 and the light intensity detector 87. The light collecting optical system collects the light split by the beam splitter 86 and makes it enter the light intensity detector 87.

[0044] The light amount detector 87 outputs an electrical signal corresponding to the amount of light incident on the light receiving surface. The light amount detector 87 has, for example, a photodiode. The light amount detector 87 is used for measuring the amount of light, which will be described later.

[0045] 5 is a block diagram showing the configuration of the control unit 9 shown in FIG. The control unit 9 has a processor such as a CPU and a storage unit 99 electrically connected to the processor and including a memory such as RAM and a storage device such as a hard disk. The processor executes computer programs stored in the storage unit 99 to function as a lighting control unit 91, a stage control unit 93, and a drawing control unit 95. Note that at least some of the functions of the control unit 9 may be realized in hardware using dedicated circuits.

[0046] The illumination control unit 91 controls the light irradiation unit 5 of the exposure unit U to emit a line beam from the light irradiation unit 5 to the exposure head 4. The stage control unit 93 controls the stage movement mechanism 2 to move the stage 10 relative to the exposure head 4. The imaging control unit 95 controls the spatial light modulator 41 via a driver 951. That is, the imaging control unit 95 provides a control signal to the driver 951 based on imaging data stored in the storage unit 99. The driver 951 then applies a drive voltage to each movable ribbon 65 according to the control signal. This causes the spatial light modulator 41 to modulate the laser light so as to correspond to the imaging pattern of the imaging data. The imaging control unit 95 determines an appropriate range of the drive voltage (hereinafter referred to as the "appropriate drive range"), as will be described later.

[0047] When a pattern is written on the substrate W in the exposure apparatus 100, the substrate W coated with a photosensitive material is held by the stage 10, and alignment of the substrate W is performed. Thereafter, the stage control unit 93 controls the stage movement mechanism 2 to move the stage 10 in the Y direction (main scanning direction) relative to each exposure head 4. Then, the writing control unit 95 controls the spatial light modulator 41 according to the position of the stage 10, so that the laser light is spatially modulated into line-shaped diffracted light corresponding to the writing pattern of the writing data, and the light is irradiated onto the substrate W. As a result, a strip-shaped region extending in the Y direction on the upper surface of the substrate W is exposed. After the movement in the Y direction is completed, the stage 10 is moved in the X direction (sub-scanning direction) by an amount equal to the width of the strip-shaped region. By repeatedly performing such stage movement in the Y direction and stage movement in the X direction, a pattern is written over the entire upper surface of the substrate W.

[0048] <Light intensity voltage characteristics of spatial light modulators> 6A and 6B are diagrams illustrating a method for determining an appropriate driving range. FIG. 6A is a diagram illustrating the light quantity distribution for a plurality of applied voltages V1 to V5. In FIG. 6A, the horizontal axis indicates the pixel position (corresponding to the position of each channel) on the exposure surface, and the vertical axis indicates the light quantity (light intensity). FIG. 6B is a diagram illustrating the light quantity-voltage characteristic, which is the change in light quantity with respect to the driving voltage, for the channel corresponding to the specific position X shown in FIG. 6A.

[0049] As shown in FIG. 6A, in order to obtain the light intensity voltage characteristics of each channel, the minimum drive voltage (V1) is applied to all channels of the spatial light modulator 41, and the light intensity distribution is measured. The drive voltage is increased stepwise, for example, from V1 to V5, and the light intensity distribution for each drive voltage is measured. As a result, a graph showing the light intensity-voltage characteristics, such as that shown in Figure 6(B), is obtained for each channel. Then, for each channel, the voltage Va at which the light intensity is maximum (Pmax) (ON state) and the voltage Vb at which the light intensity is minimum (Pmin) (OFF state) are determined.

[0050] FIG. 7 is a diagram showing the light intensity distribution Dq when the light intensity of all channels is minimized. When adjusting the light intensity in the off state (i.e., adjusting the light intensity on the dark side), it is possible to adjust all channels so that they have the minimum light intensity Pmin. However, as shown in FIG. 7, there is variation in the minimum light intensity Pmin between channels, and the light intensity distribution on the exposure surface is not uniform. As shown in FIG. 7, there are many channels with relatively high intensity. Therefore, in order to perform high-resolution exposure, it is desirable to suppress the variation in light intensity in the off state as well. To achieve this, it is desirable to adjust the detection range of the light intensity detector 87 to the low light intensity side.

[0051] On the other hand, when adjusting the light intensity on the bright side and the dark side using the same light intensity detector 87, if an attempt is made to fit both the minimum light intensity Pmin and the maximum light intensity Pmax within the detection range of the light intensity detector 87, the data near the minimum light intensity Pmin will be heavily influenced by noise. On the other hand, if the detection range is adjusted to the low light intensity side, the output near the maximum light intensity Pmax will be saturated, making it difficult to adjust the maximum light intensity Pmax.

[0052] In this embodiment, in order to measure diffracted light of relatively high intensity, such as the maximum light intensity Pmax, using a light intensity detector 87 whose detection range is set to the low light intensity side, the diffracted light is attenuated so that the diffracted light falls within the detection range. The configuration of a light intensity measurement unit 8U that performs such light intensity measurement will be described with reference to FIG.

[0053] 8A and 8B are diagrams showing a schematic configuration of the light intensity measurement unit 8U in the observation unit 8. FIG. 8A shows the light intensity measurement unit 8U when measuring the intensity of low-intensity diffracted light L1, which is diffracted light with a low light intensity (a light intensity within the detection range of the light intensity detector 87). FIG. 8B shows the light intensity measurement unit 8U when measuring the intensity of high-intensity diffracted light L2, which is diffracted light with a high light intensity (for example, a light intensity greater than the detection range). The light intensity measurement unit 8U includes a magnifying optical system 82, a beam splitter 86, a light intensity detector 87, an aperture 88, and a light attenuation unit 89.

[0054] Aperture 88 is formed in a plate shape and is disposed between beam splitter 86 and light amount detector 87. Aperture 88 has a first opening 881 and a second opening 882. First opening 881 and second opening 882 are through holes provided in aperture 88. Second opening 882 is positioned away from first opening 881 in a direction parallel to the detection surface of light amount detector 87 (here, the Z-axis direction).

[0055] The light-attenuating unit 89 is a member that reduces the intensity of the diffracted light, and is formed, for example, by a light-reducing filter or a polarizing plate. The light-attenuation rate of the light-attenuating unit 89 is not particularly limited, but it is desirable that the light amount of the diffracted light be reduced to about 1 / 10 of the original amount. The light-attenuating unit 89 is fixed to the aperture 88, and is disposed in the second opening 882. The light-attenuating unit 89 may be disposed inside the second opening 882, or may be disposed separately in front of or behind the second opening 882.

[0056] As described above, the observation unit 8 is fixed to the stage 10. Therefore, when the control unit 9 controls the main scanning mechanism 25 (moving unit) to move the stage 10 in the Y-axis direction, the light quantity measuring unit 8U provided in the observation unit 8 is also moved in the Y-axis direction. In other words, the light attenuating unit 89 is moved in the Y-axis direction. As will be described later, the control unit 9 and the main scanning mechanism 25 (moving unit) switch the position of the light attenuating unit 89 with respect to the diffracted light between a position on the optical path of the diffracted light and a position away from the optical path of the diffracted light.

[0057] 8A, when measuring the low-intensity diffracted light L1, the low-intensity diffracted light L1 from the projection optical system 43 travels parallel to the Z-axis direction toward the -Z direction, passes through the magnifying optical system 82, and is then reflected in the +Y direction by the beam splitter 86. The reflected low-intensity diffracted light L1 then travels parallel to the Y-axis direction, passes through a first opening 881 of the aperture 88, and is incident on the light intensity detector 87. In this way, when measuring the low-intensity diffracted light L1, the attenuation unit 89 is disposed at a position away from the optical path of the low-intensity diffracted light L1 (a position outside the optical path). Therefore, the low-intensity diffracted light L1 is incident on the light intensity detector 87 without being attenuated.

[0058] On the other hand, when measuring the high-intensity diffracted light L2, as shown in FIG. 8B, the light intensity measurement unit 8U is moved a predetermined distance in the +Y direction from the position shown in FIG. 8A. As a result, the incident position of the high-intensity diffracted light L2 from the projection optical system 43 onto the beam splitter 86 is shifted toward the +Y side from the incident position of the low-intensity diffracted light L1 shown in FIG. 8A. The high-intensity diffracted light L2 reflected by the beam splitter 86 then passes through the second opening 882 and the attenuation unit 89 and is incident on the light intensity detector 87. Letting the movement amount of the light intensity measurement unit 8U be ΔY and the magnification ratio of the magnification optical system 82 be M, the incident position of the high-intensity diffracted light L2 onto the light intensity detector 87 is shifted by ΔY × M in the -Z direction from the incident position of the low-intensity diffracted light L1. In this way, when measuring the high-intensity diffracted light L2, the attenuation unit 89 is disposed at a position on the optical path of the high-intensity diffracted light L2. As a result, the high-intensity diffracted light L2 is attenuated and enters the light intensity detector 87.

[0059] According to the exposure apparatus 100 of this embodiment, it is possible to attenuate the high-intensity diffracted light L2. Therefore, even if the detection range of the light intensity detector 87 is set to the low-intensity side in order to detect the low-intensity diffracted light L1 with high sensitivity, it is possible to properly detect the high-intensity diffracted light L2. In other words, it is possible to properly measure both the low-intensity diffracted light L1 and the high-intensity diffracted light L2 using a single light intensity detector 87.

[0060] 2. Second Embodiment Next, a second embodiment will be described. In the following description, elements having the same functions as elements already described will be given the same reference numerals or reference numerals with an additional alphabetical character, and detailed description thereof may be omitted.

[0061] 9A and 9B are diagrams showing a light intensity measurement unit 8Ua of an exposure apparatus 100 according to the second embodiment. Fig. 9A is a diagram showing the light intensity measurement unit 8Ua when measuring the light intensity of low-intensity diffracted light L1. Fig. 9B is a diagram showing the light intensity measurement unit 8Ua when measuring the light intensity of high-intensity diffracted light L2.

[0062] The light quantity measuring unit 8Ua includes a moving unit 891 that moves the light quantity detector 87 and the aperture 88 in the Z-axis direction parallel to the detection surface of the light quantity detector 87. The moving unit 891a is configured with a driving mechanism such as a linear motor mechanism or a ball screw mechanism, and is controlled by the control unit 9.

[0063] When measuring the low-intensity diffracted light L1, the light intensity measuring unit 8Ua passes the low-intensity diffracted light L1 through the first opening 881 and causes it to enter the light intensity detector 87, as shown in FIG. 9A. On the other hand, when measuring the high-intensity diffracted light L2, the moving unit 891 moves the light intensity detector 87 and the aperture 88 in the Z-axis direction, as shown in FIG. 9B. This positions the second opening 882 and the attenuation unit 89 on the optical path of the high-intensity diffracted light L2. Therefore, the high-intensity diffracted light L2 is attenuated by the attenuation unit 89 before entering the light intensity detector 87.

[0064] According to the light intensity measuring unit 8Ua, as with the light intensity measuring unit 8U of the first embodiment, even if the detection range of the light intensity detector 87 is set on the low light intensity side, the high light intensity diffracted light L2 can be dimmed by the dimming unit 89, thereby making it possible to measure the light intensity of the high light intensity diffracted light L2 with high sensitivity.

[0065] Furthermore, in the light quantity measuring unit 8Ua, only the light quantity detector 87 and the aperture 88 are moved, so that the light quantity can be measured without moving the stage 10. This makes it possible to easily measure the light quantity.

[0066] 3. Third Embodiment Figure 10 shows a light quantity measuring unit 8Ub of the exposure apparatus 100 according to the third embodiment. Figure 10(A) shows the light quantity measuring unit 8Ub when measuring the quantity of low-intensity diffracted light L1. Figure 10(B) shows the light quantity measuring unit 8Ub when measuring the quantity of high-intensity diffracted light L2.

[0067] The light quantity measuring unit 8Ub has one first opening 881 formed in an aperture 88. The light attenuating unit 89 is not fixed to the aperture 88, but is provided so as to be movable relative to the aperture 88. The light quantity measuring unit 8Ua also has a moving unit 891a that moves the light attenuating unit 89 in the Z-axis direction. The moving unit 891a is configured with a drive mechanism such as a linear motor mechanism or a ball screw mechanism, and is controlled by the control unit 9.

[0068] In the light intensity measurement unit 8Ub, the low-light-intensity diffracted light L1 and the high-light-intensity diffracted light L2 pass through the same first opening 881 and enter the light intensity detector 87. However, when measuring the low-light-intensity diffracted light L1, the moving unit 891a positions the attenuation unit 89 at a position away from the optical path of the low-light-intensity diffracted light L1, as shown in FIG. 10(A). On the other hand, when measuring the high-light-intensity diffracted light L2, the moving unit 891a positions the attenuation unit 89 at a position on the optical path of the high-light-intensity diffracted light L2, as shown in FIG. 10(B). Therefore, the high-light-intensity diffracted light L2 is attenuated by the attenuation unit 89 and enters the light intensity detector 87.

[0069] As with the light quantity measuring unit 8U of the first embodiment, even if the detection range of the light quantity detector 87 is set on the low light quantity side, the light quantity measuring unit 8Ub can measure the quantity of the high light quantity diffracted light L2 with high sensitivity by attenuating the high light quantity diffracted light L2 with the attenuation unit 89. Furthermore, with the light quantity measuring unit 8Ub of this modification, only the attenuation unit 89 is moved, so the moving unit can be made smaller.

[0070] 4. Fourth Embodiment FIG. 11 is a diagram illustrating an aperture 88 and a light-attenuating unit 89a according to the fourth embodiment. As shown in FIG. 11, the aperture 88 has a first opening 881, which has a portion where the light-attenuating unit 89a is not arranged and a portion where the light-attenuating unit 89a is arranged. The light-attenuating unit 89a has a first light-attenuating unit 892, a second light-attenuating unit 893, and a third light-attenuating unit 894, each of which has a different light-attenuation rate. Specifically, the light-attenuating rate increases in the order of the first light-attenuating unit 892, the second light-attenuating unit 893, and the third light-attenuating unit 894. The first light-attenuating unit 892, the second light-attenuating unit 893, and the third light-attenuating unit 894 are arranged in a direction parallel to the detection surface of the light intensity detector 87 (the Z-axis direction).

[0071] The light attenuating section 89a can attenuate the diffracted light in multiple stages by adjusting the incident position of the diffracted light relative to the light attenuating section 89a. By employing the light attenuating section 89a, the degree of attenuation can be changed in multiple stages according to the amount of diffracted light (intensity) to be measured, so that the amount of light can be measured appropriately.

[0072] <5. Variations> Although the embodiments have been described above, the present invention is not limited to the above and various modifications are possible.

[0073] For example, in the first embodiment, the light quantity measurement unit 8U including the attenuation unit 89 is moved in the Y-axis direction relative to the projection optical system 43, which is fixed in a fixed position. However, the projection optical system 43 may be moved in the Y-axis direction while the light quantity measurement unit 8U including the attenuation unit 89 remains fixed. Note that by moving the stage 10 instead of moving the projection optical system 43, a large-scale drive mechanism for moving the projection optical system 43 is not required. Furthermore, by not moving the projection optical system 43, it is possible to prevent the projection optical system 43 from shifting.

[0074] Furthermore, in the second embodiment, the moving unit 891 integrally moves both the light amount detector 87 and the aperture 88. However, the moving unit 891 may be configured to move only the aperture 88 in the Z-axis direction while the light amount detector 87 is fixed in a fixed position.

[0075] Although the present invention has been described in detail, the above description is merely illustrative in all respects and does not limit the present invention. It is understood that countless variations not illustrated can be envisioned without departing from the scope of the present invention. The configurations described in the above embodiments and variations can be combined or omitted as appropriate as long as they are not mutually inconsistent. [Explanation of symbols]

[0076] 10: Stage 25: Main scanning mechanism (moving part) 41: Spatial light modulator 43: Projection optical system (optical system) 52: Laser oscillator (light source) 87: Light detector 88: Aperture 89, 89a: Light-reducing section 100: exposure device 881: First opening 882: Second opening 891,891a: Moving part W: Substrate

Claims

1. An exposure apparatus for exposing a surface of an object, comprising: A light source and a diffractive spatial light modulator that modulates the intensity of the light by diffracting the light emitted from the light source; an optical system that forms an image of the diffracted light diffracted by the spatial light modulator; a light intensity detector that detects the amount of the diffracted light that has passed through the optical system; a light-attenuating unit capable of attenuating the diffracted light incident on the light amount detector; a moving unit that switches a position of the attenuation unit with respect to the diffracted light between a position on the optical path of the diffracted light and a position away from the optical path; An exposure apparatus comprising:

2. 2. The exposure apparatus according to claim 1, The exposure apparatus, wherein the light attenuation section has a light attenuation filter or a polarizing plate.

3. 3. The exposure apparatus according to claim 1, a stage for supporting the substrate; Furthermore, the light attenuating unit and the light amount detector are fixed to the stage, The moving unit moves the stage.

4. 3. The exposure apparatus according to claim 1, The moving unit moves the attenuation unit relative to the optical system, which is fixed in a fixed position.

5. 3. The exposure apparatus according to claim 1, an aperture having a plurality of openings through which the diffracted light can pass; and an exposure apparatus, wherein the attenuation unit is located in any one of the plurality of openings;

6. 3. The exposure apparatus according to claim 1, The exposure apparatus, wherein the attenuation unit is capable of attenuating the diffracted light in a plurality of stages.

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