Method for measurement, method for usage, method for determination, measurement device, spatial light modulation device, and program

Abstract

To provide a technique of precisely measuring the amount of deflection of a movable ribbon of a spacial light converter and downsizing a unit necessary for measurement more than an existing technique.SOLUTION: A measured value G*Vout, which reflects an electric resistance value R1 of a movable ribbon 61, is acquired. The measured value G*Vout is converted to the amount of the deflection of the movable ribbon 61. In other words, the deflection amount ε of the movable ribbon 61 is measured not by optical means but by electric means. The amount ε of deflection of the movable ribbon 61 can be thus precisely measured and a unit necessary for measurement can be downsized more than when optical means is used.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a technique for measuring the amount of deflection of a plurality of movable ribbons in a spatial light modulator that can be displaced by applying a voltage. [Background technology]

[0002] Conventionally, a diffraction grating type spatial light modulator may be used in manufacturing devices such as exposure devices, drawing devices, and CTP (Computer to Plate) devices that irradiate light onto an object. The spatial light modulator has multiple movable ribbons that can be displaced by applying a voltage. The spatial light modulator controls the voltage value applied to each movable ribbon, and modulates the light into a predetermined pattern by changing the state of the diffracted light reflected on the surface of the movable ribbon.

[0003] A conventional device equipped with a diffraction grating type spatial light modulator is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5004279 specification Summary of the Invention [Problem to be solved by the invention]

[0005] In a spatial light modulator, the position of the reflective surface of the movable ribbon must be precisely controlled. However, the movable ribbon may bend in the initial state when no voltage is applied due to manufacturing errors or the effects of gravity. This bending may cause slight variations in the optical properties of the multiple movable ribbons.

[0006] In conventional spatial light modulators, the intensity of reflected light when a voltage is applied to each movable ribbon is measured to obtain the variation in optical characteristics caused by the initial bending of each movable ribbon, and the voltage applied to each movable ribbon is adjusted according to the obtained variation in optical characteristics.

[0007] However, it is difficult to accurately measure the amount of deflection of each movable ribbon using conventional optical measurement. In addition, the conventional method requires a unit for measuring the intensity of reflected light, and miniaturizing the unit is a challenge.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a technology that can accurately measure the amount of deflection of a movable ribbon of a spatial light modulator, while making the unit required for measurement smaller than conventional units. [Means for solving the problem]

[0009] In order to solve the above problems, the first invention of the present application is a measurement method for measuring the amount of deflection of movable ribbons in a spatial light modulator having a plurality of movable ribbons that can be displaced by applying a voltage, the method comprising a measurement process for obtaining a measurement value reflecting the electrical resistance value of the movable ribbons, and a conversion process for converting the measurement value obtained by the measurement process into the amount of deflection of the movable ribbons.

[0010] A second aspect of the present invention is the measurement method of the first aspect, wherein the measurement step includes applying a measurement voltage to a bridge circuit including the movable ribbon, and measuring a voltage value output from the bridge circuit.

[0011] The third invention of the present application is a measurement method of the first and second inventions, wherein the measurement voltage applied to the movable ribbon in the measurement process is smaller than the driving voltage applied to the movable ribbon when the spatial light modulator is in use.

[0012] A fourth invention of the present application is a measurement method according to any one of the first to third inventions, wherein in the conversion process, the measurement value is converted into the amount of deflection based on correspondence data indicating a correspondence between the measurement value and the amount of deflection.

[0013] The fifth invention of the present application is a method of using the spatial light modulator utilizing the measurement method of any one of the first to fourth inventions, in which the driving voltage applied to the movable ribbon is corrected based on the amount of deflection obtained by the conversion process.

[0014] The sixth invention of the present application is a method for determining whether or not the spatial light modulator can be used by utilizing the measurement method of any one of the first to fourth inventions, and if the amount of deflection obtained by the conversion process is less than a predetermined threshold, it is determined that the spatial light modulator can be used, and if the amount of deflection is equal to or greater than the threshold, it is determined that the spatial light modulator cannot be used.

[0015] The seventh invention of the present application is a measurement device that measures the amount of deflection of movable ribbons in a spatial light modulator having a plurality of movable ribbons that can be displaced by applying a voltage, and includes a measurement circuit that obtains a measurement value reflecting the electrical resistance value of the movable ribbons, and a conversion processing unit that converts the measurement value obtained by the measurement circuit into the amount of deflection of the movable ribbons.

[0016] An eighth aspect of the present invention is the measurement device of the seventh aspect, wherein the measurement circuit has a bridge circuit including the movable ribbon.

[0017] A ninth aspect of the present invention is a measuring device according to the seventh or eighth aspect of the present invention, further comprising a memory unit in which correspondence data indicating a correspondence between the measurement value and the amount of deflection is stored, and the conversion processing unit converts the measurement value into the amount of deflection based on the correspondence data.

[0018] The tenth invention of the present application is a spatial light modulator equipped with a measurement device of any one of the seventh to ninth inventions, and is equipped with a voltage application circuit that applies a voltage to the movable ribbon, and a control unit that controls the voltage application circuit, and the control unit corrects the driving voltage applied to the movable ribbon by the voltage application circuit based on the amount of deflection obtained by the conversion processing unit.

[0019] An eleventh invention of the present application is a spatial light modulator equipped with a measurement device of any one of the seventh to ninth inventions, and comprising a control unit that determines that the spatial light modulator is usable when the amount of deflection obtained by the conversion processing unit is less than a predetermined threshold, and determines that the spatial light modulator is unusable when the amount of deflection is equal to or greater than the threshold.

[0020] The twelfth invention of the present application is a program for measuring the amount of deflection of movable ribbons in a spatial light modulator having a plurality of movable ribbons that can be displaced by applying a voltage, which causes a computer to execute a measurement process for obtaining a measurement value reflecting the electrical resistance value of the movable ribbons, and a conversion process for converting the measurement value obtained by the measurement process into the amount of deflection of the movable ribbons. Effect of the Invention

[0021] According to the first to twelfth aspects of the present invention, the amount of deflection of the movable ribbon is measured by electrical means, not optical means. This allows the amount of deflection of the movable ribbon to be measured with high accuracy, and the unit required for measurement can be made smaller than when optical means are used.

[0022] In particular, according to the second and eighth aspects of the present invention, a measurement value reflecting the resistance value of the movable ribbon can be obtained using a relatively simple measurement circuit.

[0023] In particular, according to the third aspect of the present invention, it is possible to prevent the movable ribbon from being displaced by the measurement voltage, and therefore it is possible to measure the amount of bending of the movable ribbon in a state close to the initial state in which no voltage is applied to the movable ribbon.

[0024] In particular, according to the fourth and ninth aspects of the present invention, the amount of deflection can be found with reduced error compared to the case where the amount of deflection is calculated by substituting the measured value into a predetermined formula.

[0025] In particular, according to the fifth and tenth aspects of the present invention, it is possible to suppress errors due to bending of the movable ribbons and to perform light modulation by the spatial light modulator with high accuracy.

[0026] In particular, according to the sixth and eleventh aspects of the present invention, when the amount of bending of the movable ribbon is too large, the use of the spatial light modulator can be prohibited. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a schematic perspective view of an exposure apparatus. [Diagram 2] FIG. 2 is a control block diagram of the exposure apparatus. [Diagram 3] FIG. 2 is a top view of the spatial light modulator. [Figure 4] FIG. 2 is a side view of the spatial light modulator. [Diagram 5] FIG. 2 is a circuit diagram of an electrical circuit when the spatial light modulator is in use. [Figure 6] 11 is a circuit diagram of an electric circuit when measuring the amount of deflection of a movable ribbon. FIG. [Figure 7] 10 is a flowchart showing a flow of operations when measuring the amount of flexure of a movable ribbon. [Figure 8] FIG. 11 is a diagram showing an example of correspondence data. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0029] <1. Configuration of exposure equipment> 1 is a schematic perspective view of an exposure apparatus 1 equipped with a spatial light modulator 60 according to one embodiment of the present invention. This exposure apparatus 1 is an apparatus that irradiates modulated light onto the upper surface of a substrate 9, such as a semiconductor wafer on which a photosensitive material is applied, to expose a pattern on the upper surface of the substrate 9. As shown in FIG. 1, the exposure apparatus 1 is equipped with a base 10, a stage 20, a moving mechanism 30, an exposure unit 40, and a control unit 50.

[0030] The base 10 is a support platform that supports the moving mechanism 30 and the exposure unit 40. The base 10 has a flat plate-like outer shape that extends in the main scanning direction and the sub-scanning direction. The base 10 is fixed to the floor of a factory.

[0031] The stage 20 is a flat plate that holds the substrate 9. The stage 20 has a flat upper surface. The substrate 9 is placed on the upper surface of the stage 20 in a substantially horizontal position. The stage 20 may have chuck pins that fix the substrate 9 and a plurality of suction holes that suction the substrate 9.

[0032] The moving mechanism 30 is a mechanism that moves the stage 20 relative to the base 10. The moving mechanism 30 includes a main scanning mechanism 31 and a sub-scanning mechanism 32. The main scanning mechanism 31 moves the stage 20 in a main scanning direction along a horizontal plane. The sub-scanning mechanism 32 moves the stage 20 in a sub-scanning direction that is a direction along the horizontal plane and perpendicular to the main scanning direction. When the stage 20 moves in the main scanning direction and the sub-scanning direction, the substrate 9 is also transported in the main scanning direction and the sub-scanning direction together with the stage 20.

[0033] For example, a mechanism that converts the rotational motion of a motor into linear motion using a ball screw, or a mechanism using a linear motor, is used for the main scanning mechanism 31 and the sub-scanning mechanism 32. The movement mechanism 30 may also include a lifting mechanism that moves the stage 20 in the vertical direction, or a rotation mechanism that rotates the stage 20 around an axis extending in the vertical direction.

[0034] The exposure unit 40 is a unit that exposes the substrate 9 held by the stage 20. The exposure unit 40 is located above the stage 20. As shown in Fig. 1, the exposure unit 40 is fixed to a frame 44 having a bridge structure that is erected on the base 10. In this embodiment, two exposure units 40 are fixed to the frame 44 while being aligned in the sub-scanning direction.

[0035] As shown in Fig. 1, each of the two exposure units 40 has a head 41, an illumination optical system 42, and a laser oscillator 43. The laser oscillator 43 emits pulsed light in accordance with a drive signal supplied from a control unit 50. The pulsed light emitted from the laser oscillator 43 is introduced into the head 41 via the illumination optical system 42. A spatial light modulator 60 is provided inside the head 41. The pulsed light introduced into the head 41 is modulated into a predetermined pattern by the spatial light modulator 60 and irradiated onto the upper surface of the substrate 9. As a result, the photosensitive material on the upper surface of the substrate 9 is exposed.

[0036] When the exposure apparatus 1 is in operation, the transport of the substrate 9 by the movement mechanism 30 and the exposure by the head 41 are repeatedly executed. Specifically, the exposure apparatus 1 exposes a strip-shaped area (swath) extending in the main scanning direction on the upper surface of the substrate 9 by irradiating pulsed light from the head 41 while transporting the stage 20 in the main scanning direction by the main scanning mechanism 31. Thereafter, the exposure apparatus 1 moves the stage 20 in the sub-scanning direction by one swath by the sub-scanning mechanism 32, and performs exposure in the main scanning direction again. In this way, the exposure apparatus 1 exposes a pattern onto the entire upper surface of the substrate 9 by repeating exposure in the main scanning direction and movement of the stage 20 in the sub-scanning direction.

[0037] The control unit 50 is a unit for controlling the operation of each part of the exposure apparatus 1. FIG. 2 is a control block diagram of the exposure apparatus 1. As conceptually shown in FIG. 2, the control unit 50 is composed of a computer having a processor 51 such as a CPU, a memory 52 such as a RAM, and a storage unit 53 such as a hard disk drive. The storage unit 53 stores an exposure program P1 for causing the exposure apparatus 1 to execute an exposure process, and a measurement program P2 for performing a deflection measurement of the spatial light modulator 60, which will be described later. The exposure program P1 and the measurement program P2 may be stored in a storage medium such as an optical disk.

[0038] 2, the control unit 50 is electrically connected to the main scanning mechanism 31, the sub-scanning mechanism 32, the laser oscillator 43, a ribbon power supply 711, a common power supply 712, a first switch 73, a second switch 74, and an amplifier 725, which will be described later. The control unit 50 controls each of the above-mentioned parts according to an exposure program P1, thereby executing an exposure process for the substrate 9. The control unit 50 also controls each of the above-mentioned parts according to a measurement program P2, thereby executing a deflection measurement of the movable ribbon 61, which will be described later.

[0039] 2. Configuration of spatial light modulator Next, the configuration of the spatial light modulator 60 used in the exposure unit 40 will be described. Fig. 3 is a top view of the spatial light modulator 60. Fig. 4 is a side view of the spatial light modulator 60. This spatial light modulator 60 is a so-called diffraction grating type light modulator that modulates the ON / OFF of reflected light by changing the diffracted light at each position on the reflecting surface. For example, a GLV (Grating Light Valve) (registered trademark) is used for the spatial light modulator 60.

[0040] As shown in FIGS. 3 and 4, the spatial light modulator 60 has a plurality of movable ribbons 61, a plurality of fixed ribbons 62, and a common electrode 63.

[0041] The multiple movable ribbons 61 are arranged at regular intervals in a predetermined direction (hereinafter referred to as the "first direction"). Each movable ribbon 61 is a metal piece extending in a direction perpendicular to the first direction (hereinafter referred to as the "second direction"). The upper surface of the movable ribbon 61 is a mirror surface capable of reflecting light. Both ends of the movable ribbon 61 in the second direction are fixed to the ribbon mounting surface 64 of the spatial light modulator 60. The center of the movable ribbon 61 in the second direction is located above and spaced from the ribbon mounting surface 64, and is capable of bending in the vertical direction.

[0042] The multiple fixed ribbons 62 are disposed between adjacent movable ribbons 61 in the first direction. That is, the movable ribbons 61 and the fixed ribbons 62 are arranged alternately along the first direction. Each fixed ribbon 62 is a metal piece extending in the second direction. The upper surface of the fixed ribbon 62 is a mirror surface capable of reflecting light. The entire second direction of each fixed ribbon 62 is fixed to the ribbon mounting surface 64 of the spatial light modulator 60. Therefore, the fixed ribbons 62 do not bend in the vertical direction.

[0043] The common electrode 63 is a single metal piece disposed below the multiple movable ribbons 61 and the multiple fixed ribbons 62. The common electrode 63 extends in the first and second directions along the ribbon mounting surface 64. The lower surfaces of the multiple movable ribbons 61 and the upper surface of the common electrode 63 face each other with a gap therebetween in the vertical direction.

[0044] The spatial light modulator 60 also has an electric circuit 70 connected to the movable ribbons 61 and the common electrode 63. Figures 5 and 6 are circuit diagrams of the electric circuit 70. As shown in Figures 5 and 6, the electric circuit 70 includes a voltage application circuit 71, a measurement circuit 72, a first switch 73, and a second switch 74.

[0045] The voltage application circuit 71 is a circuit for applying a voltage to the multiple movable ribbons 61 and the common electrode 63. As shown in Figs. 5 and 6, the voltage application circuit 71 has a ribbon power supply 711 and a common power supply 712. The anode of the ribbon power supply 711 is connected to one end of the movable ribbon 61 via a conductor. The other end of the movable ribbon 61 is connected to a first switch 73. The cathode of the ribbon power supply 711 is grounded via a conductor. The anode of the common power supply 712 is connected to one end of the common electrode 63 via a conductor. The other end of the common electrode 63 is open. The cathode of the common power supply 712 is grounded via a conductor.

[0046] 5 and 6 show one movable ribbon 61 and one ribbon power supply 711 that supplies voltage to the movable ribbon 61, but the voltage application circuit 71 has a ribbon power supply 711 for each movable ribbon 61. The multiple ribbon power supplies 711 are connected in parallel, and one ribbon power supply 711 is connected to one movable ribbon 61.

[0047] The ribbon power supply 711 is a variable power supply capable of changing the voltage value it outputs. The ribbon power supply 711 changes the voltage applied to the movable ribbon 61 according to a control signal input from the control unit 50. In this embodiment, the common power supply 712 is also a variable power supply capable of changing the voltage it outputs. The common power supply 712 changes the voltage applied to the common electrode 63 according to a control signal input from the control unit 50. However, the common power supply 712 may be a fixed power supply that outputs only a constant voltage value.

[0048] The first switch 73 is interposed between the movable ribbon 61 and a second resistor 722 described later. In response to a command from the control unit 50, the first switch 73 switches between a state in which the movable ribbon 61 is connected to the open end 731 (the state in FIG. 5 ) and a state in which the movable ribbon 61 is connected to the second resistor 722 (the state in FIG. 6 ).

[0049] The second switch 74 is interposed between a connection point 75 between the ribbon power supply 711 and the movable ribbon 61 and a third resistor 723, which will be described later. In accordance with a command from the control unit 50, the second switch 74 switches between a state in which the connection point 75 is connected to the open end 741 (the state in FIG. 5 ) and a state in which the connection point 75 is connected to the third resistor 723 (the state in FIG. 6 ).

[0050] When the spatial light modulator 60 is in use, as shown in FIG. 5, the first switch 73 is connected to the open end 731, and the second switch 74 is also connected to the open end 741. A predetermined voltage (hereinafter referred to as the "common voltage") is applied from the common power supply 712 to the common electrode 63, and a driving voltage (hereinafter referred to as the "driving voltage") is applied from the ribbon power supply 711 to the movable ribbon 61. Then, an electrostatic attraction is generated between the common electrode 63 and the movable ribbon 61 due to the potential difference between the common voltage and the driving voltage. As a result, the center of the movable ribbon 61 in the second direction is bent downward as shown by the dashed arrow in FIG. 4. As a result, the height of the upper surface of the movable ribbon 61 is displaced according to the magnitude of the driving voltage.

[0051] Furthermore, when the spatial light modulator 60 is in use, line light shaped into a straight line extending in the first direction is irradiated from the illumination optical system 42 toward the upper surfaces of the multiple movable ribbons 61 and the multiple fixed ribbons 62. At this time, the intensity of the specularly reflected light and diffracted light changes depending on the difference in height between the adjacent movable ribbons 61 and fixed ribbons 62. For this reason, by adjusting the drive voltage for each movable ribbon 61 and selectively using the specularly reflected light and diffracted light, it is possible to switch ON / OFF of the output light at each position in the first direction.

[0052] <3. Measuring the deflection of a movable ribbon> In such a spatial light modulator 60, the vertical position of the movable ribbons 61 must be precisely controlled. However, the movable ribbons 61 may be slightly bent in the vertical direction in the initial state where no voltage is applied due to manufacturing errors or the effects of gravity. For this reason, when using the spatial light modulator 60, the operation of the movable ribbons 61 must be controlled taking into account the amount of bending of the movable ribbons 61 in this initial state.

[0053] Therefore, the electrical circuit 70 of the spatial light modulator 60 includes a measurement circuit 72 for measuring the amount of deflection ε in the vertical direction of the movable ribbons 61 in the initial state. The measurement circuit 72 is electrically connected to the control unit 50. In this embodiment, the voltage application circuit 71, the measurement circuit 72, and the control unit 50 constitute a measurement device that measures the amount of deflection ε of the movable ribbons 61.

[0054] 5 and 6 show one movable ribbon 61 and one measurement circuit 72 that measures the amount of deflection ε of the movable ribbon 61, but the electric circuit 70 has a measurement circuit 72 for each movable ribbon 61. In other words, one measurement circuit 72 is connected to one movable ribbon 61.

[0055] 5 and 6, the measurement circuit 72 has a bridge circuit including the movable ribbon 61 as a first resistor 721, a second resistor 722, a third resistor 723, and a fourth resistor 724. The measurement circuit 72 also has an amplifier 725 that amplifies the output voltage of the bridge circuit.

[0056] The first resistor 721 (movable ribbon 61) and the second resistor 722 are connected in series via the first switch 73. The third resistor 723 and the fourth resistor 724 are also connected in series. Then, between the anode and cathode of the ribbon power supply 711, the string of the first resistor 721 (movable ribbon 61) and the second resistor 722 and the string of the third resistor 723 and the fourth resistor 724 are connected in parallel.

[0057] In addition, a midpoint M1 between the first resistor 721 (movable ribbon 61) and the second resistor 722, and a midpoint M2 between the third resistor 723 and the fourth resistor 724 are connected to an input terminal of an amplifier 725.

[0058] The second resistor 722, the third resistor 723, and the fourth resistor 724 are fixed resistors with constant electrical resistance values. That is, the resistance value R2 of the second resistor 722, the resistance value R3 of the third resistor 723, and the resistance value R4 of the fourth resistor 724 are constant values. In contrast, the electrical resistance value R1 of the first resistor 721 changes according to the amount of bending ε of the movable ribbon 61 in the up-down direction.

[0059] When the resistance value R1 of the first resistor 721 changes, the potential of the midpoint M1 between the first resistor 721 and the second resistor 722 changes. This changes the potential difference Vout between the two midpoints M1 and M2. The amplifier 725 amplifies the potential difference Vout between the two midpoints M1 and M2 by a predetermined amplification factor G. The measurement circuit 72 then outputs the amplified potential difference G*Vout as a measurement value. Therefore, the measurement value G*Vout output from the measurement circuit 72 reflects the resistance value R1 of the first resistor 721 (movable ribbon 61).

[0060] Fig. 7 is a flowchart showing the flow of operations when measuring the amount of deflection ε in the initial state of the movable ribbon 61. Among the processes in Fig. 7, the processes of steps S1 to S5 proceed as the control unit 50 operates in accordance with the measurement program P2.

[0061] As shown in Fig. 5, when measuring the amount of deflection ε of the movable ribbon 61 in the initial state, first, the movable ribbon 61 is connected to the measurement circuit 72 (step S1). Specifically, in response to a command from the control unit 50, as shown in Fig. 6, the first switch 73 is connected to the second resistor 722, and the second switch 74 is connected to the third resistor 723. This forms the above-mentioned bridge circuit.

[0062] Next, a measurement voltage (hereinafter referred to as "measurement voltage Vin") is applied from the ribbon power supply 711 to the bridge circuit, and a measurement value G*Vout output from the amplifier 725 is obtained (step S2: measurement step).

[0063] The relationship between Vin and Vout in the bridge circuit is expressed by the following equation (1).

[0064]

number

[0065] Here, if the resistance value R1 of the first resistor 721 changes by ΔR due to the bending of the movable ribbon 61, the state of the following formula (2) is obtained.

[0066]

number

[0067] In this embodiment, resistors having a resistance value equivalent to the resistance value R1 of the first resistor 721 (movable ribbon 61) when there is no bending are used as the second resistor 722, the third resistor 723, and the fourth resistor 724. In this case, if R1=R2=R3=R4=R, the above formula (2) can be rewritten as the following formula (3).

[0068]

number

[0069] Since ΔR is sufficiently smaller than R, due to the relationship of ΔR<<R, the above formula (3) can be approximated to the following formula (4).

[0070]

number

[0071] Here, if the gauge factor specific to the material of the movable ribbon 61 is K, the relationship between the amount of bending ε of the movable ribbon 61 and the amount of change ΔR in the resistance value is expressed by the following formula (5).

[0072]

number

[0073] By substituting this formula (5) into the above formula (4), we obtain the following formula (6).

[0074]

number

[0075] In formula (6), the gauge factor K and the measurement voltage Vin are fixed values. Therefore, formula (6) indicates that the amount of deflection ε of the movable ribbon 61 and Vout have a proportional relationship. That is, it can be seen that the measurement value G*Vout output from the measurement circuit 72 changes according to the amount of deflection ε of the movable ribbon 61. The measurement circuit 72 inputs the obtained measurement value G*Vout to the control unit 50.

[0076] 6, the control unit 50 has a conversion processing unit 54. The conversion processing unit 54 is a function that is realized by the computer serving as the control unit 50 in accordance with the measurement program P2.

[0077] The conversion processing unit 54 converts the input measurement value G*Vout into the amount of deflection ε of the movable ribbon 61 (step S3: conversion step). When the gauge factor K of the movable ribbon 61 is known, the conversion processing unit 54 may calculate the amount of deflection ε of the movable ribbon 61 by substituting Vout into the above formula (6). However, when the gauge factor K is unknown or when the calculation using formula (6) has a large error, the conversion processing unit 54 may convert the measurement value G*Vout into the amount of deflection ε based on correspondence data D prepared in advance.

[0078] The correspondence data D is data that defines the relationship between the measurement value G*Vout and the amount of deflection ε of the movable ribbon 61 in the vertical direction. The correspondence data D is created in advance by experiments or the like. For example, the correspondence data D is created by intentionally deflecting the movable ribbon 61, measuring the amount of deflection ε with an optical microscope, and acquiring the measurement value G*Vout with the measurement circuit 72. The created correspondence data D is stored in the memory unit 53 of the control unit 50.

[0079] Fig. 8 is a diagram showing an example of the correspondence data D. In the correspondence data D of Fig. 8, each value on the horizontal axis representing the measurement value G*Vout and each value on the vertical axis representing the amount of deflection ε are in one-to-one correspondence with each other by the graph line L. However, the correspondence data D may be data in the form of a table that associates the measurement value G*Vout with the amount of deflection ε.

[0080] The conversion processing unit 54 specifies the amount of deflection ε in the vertical direction of the movable ribbon 61 based on the measurement value G*Vout and the correspondence data D. Specifically, the conversion processing unit 54 refers to the correspondence data D to specify the amount of deflection ε corresponding to the measurement value G*Vout output from the measurement circuit 72. This makes it possible to detect the amount of deflection ε in the vertical direction of the movable ribbon 61.

[0081] As described above, in the spatial light modulator 60, a measurement value reflecting the electrical resistance value of the movable ribbons 61 is obtained, and the measurement value is converted into the amount of flexure ε of the movable ribbons 61. That is, the amount of flexure ε of the movable ribbons 61 is measured by electrical means, not optical means. This makes it possible to measure the amount of flexure ε of the movable ribbons 61 with high accuracy, and also makes it possible to make the unit required for measurement smaller than when optical means are used.

[0082] In particular, in the spatial light modulator 60 of this embodiment, a measurement voltage is applied to a bridge circuit including the movable ribbons 61, and the voltage value output from the bridge circuit is measured. In this way, a measurement value G*Vout that reflects the resistance value of the movable ribbons 61 can be obtained with a relatively simple measurement circuit.

[0083] Furthermore, in this embodiment, the same ribbon power supply 711 is used in the measurement process for measuring the amount of flexure ε of the movable ribbon 61 in the initial state and during actual use of the spatial light modulator 60. For this reason, the number of parts of the spatial light modulator 60 can be reduced compared to the case where different power supplies are used in the measurement process and during actual use of the spatial light modulator 60.

[0084] However, it is desirable that the measurement voltage Vin applied to the movable ribbons 61 in the above measurement process is a voltage smaller than the drive voltage applied to the movable ribbons 61 when the spatial light modulator 60 is in use. Specifically, it is desirable that the measurement voltage Vin is a voltage at which the displacement of the movable ribbons 61 due to the voltage itself can be ignored. This makes it possible to measure the amount of deflection ε of the movable ribbons 61 in a state equivalent to the initial state in which no voltage is applied to the movable ribbons 61.

[0085] In order to prevent the displacement of the movable ribbon 61 due to the measurement voltage Vin itself, when measuring the amount of deflection ε of the movable ribbon 61, a voltage equivalent to the voltage applied to the movable ribbon 61 may be applied from the common power supply 712 to the common electrode 63. In this way, no electrostatic attraction due to the potential difference is generated between the movable ribbon 61 and the common electrode 63, and therefore no displacement of the movable ribbon 61 due to the electrostatic attraction occurs. Therefore, the amount of deflection ε of the movable ribbon 61 in the initial state can be measured with higher accuracy.

[0086] After measuring the amount of bending ε of each movable ribbon 61 of the spatial light modulator 60 by the above measurement, the control unit 50 judges whether the spatial light modulator 60 can be used based on the obtained amount of bending ε (step S4). Specifically, when the amount of bending ε of at least one movable ribbon 61 among the multiple movable ribbons 61 of the spatial light modulator 60 is equal to or greater than a preset threshold, the control unit 50 judges that the spatial light modulator 60 is unusable (step S4: No). In this case, the spatial light modulator 60 needs to be replaced, so the control unit 50 outputs an error to a display or the like (step S5).

[0087] On the other hand, if the deflection amount ε of all the movable ribbons 61 of the spatial light modulator 60 is less than the preset threshold value, the control unit 50 determines that the spatial light modulator 60 is usable (step S4: Yes). In this case, the control unit 50 uses the spatial light modulator 60 to perform the exposure process.

[0088] At this time, the control unit 50 corrects the drive voltage applied from the ribbon power supply 711 to the movable ribbons 61 based on the amount of bending ε of each movable ribbon 61. Specifically, the drive voltage is increased or decreased in a direction that cancels the displacement of the movable ribbons 61 caused by the amount of bending ε. This suppresses errors caused by the amount of bending ε in the initial state, and allows the spatial light modulator 60 to modulate light with greater accuracy.

[0089] <4. Modifications> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

[0090] In the above embodiment, only the amount of flexure ε in the initial state of the movable ribbon 61 was measured among the movable ribbons 61 and the fixed ribbons 62. However, the amount of flexure of the fixed ribbons 62 in the initial state may also be measured using a similar method.

[0091] Also, in the above embodiment, a description has been given of the spatial light modulator 60 used in the exposure apparatus 1. However, in a spatial light modulator used in other apparatuses such as a CTP (Computer to Plate) apparatus, the amount of deflection of the movable ribbon in the initial state may be measured using a similar method.

[0092] In the above embodiment, the control unit 50 that directly controls the spatial light modulator 60 performs the measurement process of the deflection amount ε of the movable ribbon 61. The control unit 50 also performs the conversion process from the measurement value G*Vout to the deflection amount ε, the determination of usability, etc. However, these processes may be performed by a computer for remote diagnosis that is connected to the spatial light modulator 60 via a network.

[0093] In the above embodiment, the case has been described where the amount of flexure ε of the movable ribbons 61 is measured for the spatial light modulator 60 mounted on the exposure apparatus 1 after shipment. However, the amount of flexure ε of the movable ribbons 61 of the spatial light modulator 60 may be measured by a similar method during manufacturing of the exposure apparatus 1 before shipment.

[0094] Furthermore, without departing from the spirit of the present invention, some of the elements appearing in the above-described embodiments may be deleted, or known techniques may be added to the above-described embodiments. [Explanation of symbols]

[0095] 1 Exposure equipment 9 Substrate 10 Base 20 Stages 30 Moving mechanism 40 Exposure section 41 Head 50 Control section 54 Conversion processing section 60 Spatial Light Modulator 61 Movable Ribbon 62 Fixed Ribbon 63 Common electrode 64 Ribbon placement surface 70 Electrical Circuits 71 Voltage application circuit 72 Measurement circuit 73 First Switch 74 Second Switch 711 Ribbon Power Supply 712 Common Power Supply 721 1st resistor 722 2nd resistor 723 3rd resistor 724 4th resistor 725 Amplifier P1 Exposure Program P2 Measurement Program D Correspondence Data

Claims

1. A method for measuring a deflection amount of a plurality of movable ribbons in a spatial light modulator having the plurality of movable ribbons that can be displaced by applying a voltage, comprising the steps of: a measurement step of obtaining a measurement value reflecting an electrical resistance value of the movable ribbon; a conversion step of converting the measurement value obtained by the measurement step into a deflection amount of the movable ribbon; A measurement method comprising the steps of:

2. The measurement method according to claim 1 , The measuring method, in which the measuring step applies a measuring voltage to a bridge circuit including the movable ribbon, and measures a voltage value output from the bridge circuit.

3. The measurement method according to claim 2, A measurement method, wherein a measurement voltage applied to the movable ribbons in the measurement step is smaller than a drive voltage applied to the movable ribbons when the spatial light modulator is in use.

4. The measurement method according to any one of claims 1 to 3, The conversion step converts the measurement value into the amount of deflection based on correspondence data indicating a correspondence between the measurement value and the amount of deflection.

5. A method of using the spatial light modulator using the measurement method according to any one of claims 1 to 3, comprising the steps of: A method of use comprising correcting a drive voltage applied to the movable ribbon based on the amount of deflection obtained by the conversion process.

6. A method for determining whether or not the spatial light modulator can be used by utilizing the measurement method according to any one of claims 1 to 3, comprising the steps of: If the amount of deflection obtained by the conversion step is less than a predetermined threshold, it is determined that the spatial light modulator is usable; If the amount of bending is equal to or greater than the threshold, the spatial light modulator is determined to be unusable.

7. A measurement device for measuring a deflection amount of a plurality of movable ribbons in a spatial light modulator having the plurality of movable ribbons that can be displaced by applying a voltage, comprising: a measurement circuit for obtaining a measurement value reflecting an electrical resistance value of the movable ribbon; a conversion processing unit that converts the measurement value obtained by the measurement circuit into a deflection amount of the movable ribbon; A measuring device comprising:

8. The measurement device according to claim 7, The measurement circuit comprises a bridge circuit including the movable ribbon.

9. The measurement device according to claim 7 or 8, A storage unit that stores correspondence data indicating a correspondence relationship between the measurement value and the amount of deflection. Further equipped with The conversion processing unit converts the measurement value into the amount of deflection based on the correspondence data.

10. A spatial light modulator comprising the measurement device according to claim 7 or 8, A voltage application circuit that applies a voltage to the movable ribbon; A control unit that controls the voltage application circuit; Equipped with The control unit corrects the drive voltage applied to the movable ribbon by the voltage application circuit based on the amount of deflection obtained by the conversion processing unit.

11. A spatial light modulator comprising the measurement device according to claim 7 or 8, a control unit that determines that the spatial light modulator is usable when the amount of bending obtained by the conversion processing unit is less than a predetermined threshold, and determines that the spatial light modulator is unusable when the amount of bending is equal to or greater than the threshold. A spatial light modulator comprising:

12. A program for measuring the amount of deflection of a plurality of movable ribbons in a spatial light modulator that can be displaced by applying a voltage, the program comprising: a measurement step of obtaining a measurement value reflecting an electrical resistance value of the movable ribbon; a conversion step of converting the measurement value obtained by the measurement step into a deflection amount of the movable ribbon; A program to execute.

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