Exposure apparatus and control method

Abstract

This invention provides a technology that can verify whether the timing signal for driving a spatial light modulator is appropriate. [Solution] The exposure apparatus includes a timing signal generation unit 52 and a timing signal measurement unit 56. The timing signal generation unit 52 generates a timing signal St for driving the spatial light modulator 34 based on a pulse signal Sp output from the encoder 29 in response to the movement of the substrate. The timing signal measurement unit 56 measures the period T of the timing signal St output from the timing signal generation unit 52. This allows confirmation of whether the period T of the timing signal St generated based on the pulse signal Sp of the encoder 29 is appropriate.

Description

Technical Field

[0006] ,

[0001] The present invention relates to a technique for managing the driving cycle of a spatial light modulator mounted on an exposure apparatus.

Background Art

[0002] Conventionally, an exposure apparatus for exposing a pattern on the surface of a substrate such as a semiconductor wafer or a printed circuit board is known. The exposure apparatus irradiates light from a head toward the upper surface of the substrate while moving the substrate along a horizontal plane. The head of the exposure apparatus includes a spatial light modulator such as a DMD (Digital Micromirror Device). The head irradiates the substrate with light modulated into a predetermined pattern by the spatial light modulator.

[0003] A conventional exposure apparatus provided with a spatial light modulator is described in, for example, Patent Document 1.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The exposure apparatus includes an encoder that outputs a pulse signal in accordance with the movement of the substrate. The exposure apparatus generates a timing signal for every predetermined number of pulse signals. Then, based on the timing signal, the spatial light modulator is driven. In order to improve the processing efficiency of the exposure apparatus, it is desirable to increase the moving speed of the substrate and shorten the period of the timing signal as much as possible.

[0006] However, the pulse signals output from the encoder may have a time-axis deviation called jitter error. When the pulse signal contains jitter error, an error occurs in the period of the timing signal generated based on that pulse signal. If the period of the timing signal falls below the minimum period that the spatial light modulator can drive, the pattern switching in the spatial light modulator will not function properly.

[0007] Conventional exposure systems included a margin to ensure that the timing signal period was sufficiently larger than the minimum drivable period of the spatial light modulator. However, if the margin is too large, it can lead to a decrease in the processing efficiency of the exposure system.

[0008] Therefore, the present invention aims to provide a technique for verifying whether the timing signal for driving a spatial light modulator is appropriate. [Means for solving the problem]

[0009] To solve the above problems, the first invention of the present application is an exposure apparatus for exposing a pattern on a substrate, comprising: a stage for holding the substrate; a moving mechanism for moving the stage; an encoder that outputs a pulse signal in accordance with the movement of the stage; a light source; a spatial light modulator that modulates the light emitted from the light source and irradiates the substrate with it; a timing signal generation unit that generates a timing signal based on the pulse signal output from the encoder; a modulation control unit that drives the spatial light modulator based on the timing signal; and a timing signal measurement unit that measures the period of the timing signal.

[0010] The second invention of this application is an exposure apparatus of the first invention, further comprising: a parameter storage unit that stores the shortest drivable period of the spatial light modulator and a margin time added to the shortest period; and a movement speed determination unit that determines the movement speed of the stage by the movement mechanism such that the period of the timing signal generated by the timing signal generation unit becomes the shortest period plus the margin time, wherein the margin time stored in the parameter storage unit can be reset based on the period of the timing signal measured by the timing signal measurement unit.

[0011] The third invention of this application is an exposure apparatus of the second invention, further comprising a margin setting unit that automatically resets the margin time stored in the parameter storage unit based on the period of the timing signal measured by the timing signal measurement unit.

[0012] The fourth invention of this application is an exposure apparatus according to any one of the first to third inventions, further comprising a measurement value storage unit for storing the measurement results of the timing signal measurement unit, wherein the measurement value storage unit stores only a portion of the multiple periods measured by the timing signal measurement unit, including the minimum value.

[0013] The fifth invention of this application is an exposure apparatus according to the fourth invention, wherein the measured value storage unit stores only the minimum and maximum values ​​of a plurality of periods measured by the timing signal measurement unit.

[0014] The sixth invention of the present application is a control method for managing the drive period of a spatial light modulator in an exposure apparatus that exposes a pattern on a substrate by irradiating the substrate with light from a spatial light modulator while moving the substrate, the method comprising: (a) generating a timing signal for driving the spatial light modulator based on a pulse signal output from an encoder in response to the movement of the substrate; and (b) measuring the period of the timing signal.

[0015] The seventh invention of this application is a control method of the sixth invention, further comprising the step of (c) resetting a margin time to be added to the shortest drivable period of the spatial light modulator based on the period of the timing signal measured by step (b).

[0016] The eighth invention of this application is a control method of the seventh invention, wherein in step (c), the margin time is reset so that the minimum value of the period of the timing signal measured in step (b) is greater than the shortest period.

[0017] The ninth invention of this application is a management method of any one of the sixth to eighth inventions, further comprising the step of (d) storing only a portion of the multiple periods measured by the above step (b), including the minimum value.

[0018] The tenth invention of this application is a management method of the ninth invention, wherein in step (d), only the minimum and maximum values ​​of the multiple periods measured in step (b) are stored. [Effects of the Invention]

[0019] According to the first to fifth inventions of this application, the period of the timing signal can be measured by the timing signal measurement unit. This makes it possible to confirm whether the period of the timing signal generated based on the pulse signal of the encoder is appropriate.

[0020] In particular, according to the second invention of this application, the margin time can be changed when the period of the timing signal is inappropriate. This makes it possible to optimize the period of the timing signal.

[0021] In particular, according to the third invention of this application, the period of the timing signal can be automatically optimized without any user intervention.

[0022] In particular, according to the fourth invention of the present application, it is possible to confirm whether the minimum value of the measured period is appropriate. Further, by storing only some of the measured periods instead of all the measured periods, the required storage capacity of the measurement value storage unit can be reduced.

[0023] In particular, according to the fifth invention of the present application, it is possible to confirm whether the minimum value and the maximum value of the measured period are appropriate. Further, by storing only the minimum value and the maximum value instead of all the measured periods, the required storage capacity of the measurement value storage unit can be reduced.

[0024] According to the sixth to tenth inventions of the present application, the period of the timing signal is measured. Thereby, it is possible to confirm whether the period of the timing signal generated based on the pulse signal of the encoder is appropriate.

[0025] In particular, according to the seventh invention of the present application, when the period of the timing signal is inappropriate, the margin time can be changed. Thereby, the period of the timing signal can be optimized.

[0026] In particular, according to the eighth invention of the present application, it is possible to prevent the period of the timing signal from being shorter than the shortest period that can drive the spatial light modulator.

[0027] In particular, according to the ninth invention of the present application, it is possible to confirm whether the minimum value of the measured period is appropriate. Further, by storing only some of the measured periods instead of all the measured periods, the required storage capacity can be reduced.

[0028] In particular, according to the tenth invention of the present application, it is possible to confirm whether the minimum value and the maximum value of the measured period are appropriate. Further, by storing only the minimum value and the maximum value instead of all the measured periods, the required storage capacity can be reduced.

Brief Description of the Drawings

[0029] [Figure 1] It is a schematic perspective view of an exposure apparatus. [Figure 2] This diagram shows the configuration of a part of an exposure apparatus, including an encoder. [Figure 3] This is a control block diagram of the exposure apparatus. [Figure 4] This is a block diagram that conceptually illustrates the functions of the control unit. [Figure 5] This is a graph showing the waveform of a pulse signal. [Figure 6] This graph shows the waveforms of pulse signals and timing signals. [Figure 7] This is a flowchart showing the procedure for managing the period of a timing signal. [Figure 8] This is a block diagram conceptually illustrating the function of a control unit in one modified example. [Modes for carrying out the invention]

[0030] Embodiments of the present invention will be described below with reference to the drawings.

[0031] <1. Configuration of the exposure apparatus> Figure 1 is a schematic perspective view of an exposure apparatus 1 according to one embodiment of the present invention. This exposure apparatus 1 is a device that exposes a pattern on the upper surface of a substrate 9 coated with a photosensitive material by irradiating it with light. The substrate 9 is, for example, a semiconductor wafer or a printed circuit board. As shown in Figure 1, the exposure apparatus 1 comprises a base 10, a gantry 15, a stage 20, a moving mechanism 25, an exposure unit 30, and a control unit 40.

[0032] The base 10 is a support base that supports the gantry 15, stage 20, moving mechanism 25, and exposure unit 30. The base 10 has a flat, plate-like outer shape that extends along a horizontal plane. The base 10 is made of a stone material such as quartz. The base 10 is fixed to the factory floor.

[0033] The base 10 is rectangular in shape when viewed from above. In the following, the direction along the longer side of the base 10 will be referred to as the "main scanning direction," and the direction along the shorter side of the base 10 will be referred to as the "sub-scanning direction." The main scanning direction and the sub-scanning direction are orthogonal to each other.

[0034] The gantry 15 is fixed to the upper surface of the base 10. The gantry 15 has a pair of legs 16 and a bridging portion 17. The pair of legs 16 are spaced apart in the sub-scanning direction. Each leg 16 extends upward from the upper surface of the base 10. The bridging portion 17 connects the upper ends of the legs 16 in the sub-scanning direction. A through-hole 18 is formed between the upper surface of the base 10 and the gantry 15, through which the substrate 9 can pass in the main scanning direction.

[0035] The stage 20 is a plate that holds the substrate 9. The stage 20 has a flat, plate-like shape. In a top view, the shape of the stage 20 is rectangular, smaller than the base 10. The stage 20 is positioned above the base 10 in a substantially horizontal position. The substrate 9 is supported on the upper surface of the stage 20 in a substantially horizontal position. The stage 20 may have chuck pins for fixing the substrate 9 and a plurality of suction holes for adsorbing the substrate 9.

[0036] The moving mechanism 25 is a mechanism for moving the stage 20 relative to the base 10 and the gantry 15. The moving mechanism 25 includes a main scanning mechanism 26, a sub-scanning mechanism 27, and an intermediate plate 28. The intermediate plate 28 is a flat plate-shaped member positioned between the base 10 and the stage 20.

[0037] The main scanning mechanism 26 moves the intermediate plate 28 relative to the base 10 in the main scanning direction. The main scanning mechanism 26 has a pair of guide rails and a linear motor. The pair of guide rails are rails for guiding the intermediate plate 28 in the main scanning direction. The pair of guide rails are provided on the upper surface of the base 10 at intervals in the sub-scanning direction. Each guide rail extends linearly along the main scanning direction.

[0038] The linear motor of the main scanning mechanism 26 has a stator provided on the upper surface of the base 10 and a movable element fixed to the lower surface of the intermediate plate 28. When a drive signal is supplied to the linear motor from the control unit 40, the movable element moves along the stator in the main scanning direction due to the magnetic attractive and repulsive forces generated between the stator and the movable element. As a result, the intermediate plate 28 moves in the main scanning direction relative to the base 10.

[0039] The main scanning mechanism 26 may also use a mechanism that converts the rotational motion of a motor into linear motion via a ball screw, instead of a linear motor, to move the intermediate plate 28 in the main scanning direction.

[0040] The main scanning mechanism 26 also has an encoder 29. Figure 2 is a diagram showing the configuration of a part of the exposure apparatus 1 including the encoder 29. As shown in Figure 2, the encoder 29 has a linear scale 291 and a sensor 292. The linear scale 291 is fixed to the upper surface of the base 10. The linear scale 291 has a plurality of scales 293 provided at constant minute intervals in the main scanning direction. The sensor 292 detects the scales 293 by magnetic or optical means. When the sensor 292 detects the scales 293, it outputs a pulse signal Sp to the control unit 40. Therefore, each time the intermediate plate 28 moves by a minute amount in the main scanning direction, a pulse signal Sp is output from the sensor 292 to the control unit 40.

[0041] Returning to Figure 1, the sub-scanning mechanism 27 moves the stage 20 in the sub-scanning direction relative to the intermediate plate 28. The sub-scanning mechanism 27 includes a pair of guide rails and a linear motor. The pair of guide rails are rails for guiding the stage 20 in the sub-scanning direction. The pair of guide rails are provided on the upper surface of the intermediate plate 28, spaced apart in the main scanning direction. Each guide rail extends linearly along the sub-scanning direction.

[0042] The linear motor of the sub-scanning mechanism 27 has a stator provided on the upper surface of the intermediate plate 28 and a movable element fixed to the lower surface of the stage 20. When a drive signal is supplied to the linear motor from the control unit 40, the movable element moves along the stator in the sub-scanning direction due to the magnetic attractive and repulsive forces generated between the stator and the movable element. As a result, the stage 20 moves in the sub-scanning direction relative to the intermediate plate 28.

[0043] The sub-scanning mechanism 27 may also use a mechanism that converts the rotational motion of a motor into linear motion via a ball screw, instead of a linear motor, to move the stage 20 in the sub-scanning direction.

[0044] With the substrate 9 placed on the stage 20, the exposure apparatus 1 operates the moving mechanism 25 to move the substrate 9 together with the stage 20 in the main scanning direction and the sub-scanning direction.

[0045] The moving mechanism 25 may further include a mechanism for moving the stage 20 in the vertical direction, or a mechanism for rotating the stage 20 around an axis extending in the vertical direction.

[0046] The exposure unit 30 is a unit that exposes the substrate 9 held on the stage 20. As shown in Figure 1, the exposure unit 30 has a head 31, an illumination optical system 32, and a laser oscillator 33. The head 31, the illumination optical system 32, and the laser oscillator 33 are fixed to the bridging section 17 of the gantry 15. The laser oscillator 33 is a light source that emits laser light. The laser light emitted from the laser oscillator 33 is introduced to the head 31 via the illumination optical system 32.

[0047] The head 31 has a spatial light modulator 34. For example, a reflective optical modulator such as a DMD (Digital Micromirror Device) is used as the spatial light modulator 34. However, the spatial light modulator 34 may also be a diffraction grating type optical modulator such as a GLV (Grating Light Valve) (registered trademark). The laser light introduced into the head 31 is modulated into a predetermined pattern by the spatial light modulator 34 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.

[0048] The exposure apparatus 1 moves the substrate 9 in the main scanning direction and the sub-scanning direction using the moving mechanism 25, while irradiating it with laser light from the head 31. Specifically, the exposure apparatus 1 moves the stage 20 in the main scanning direction using the main scanning mechanism 26, while irradiating it with modulated light from the head 31, thereby exposing a strip-shaped region (swath) extending in the main scanning direction on the upper surface of the substrate 9. At this time, the spatial light modulator 34 switches the pattern of light irradiated onto the substrate 9 each time the substrate 9 moves a predetermined amount in the main scanning direction, based on a signal from the control unit 40. As a result, a desired pattern is exposed on one swath on the upper surface of the substrate 9.

[0049] Subsequently, the exposure apparatus 1 moves the stage 20 by one swath in the sub-scanning direction using the sub-scanning mechanism 27, and then performs exposure again in the main scanning direction. In this way, the exposure apparatus 1 exposes the entire upper surface of the substrate 9 by repeatedly performing exposure in the main scanning direction and moving the stage 20 in the sub-scanning direction.

[0050] The control unit 40 is a unit for controlling the operation of each part of the exposure apparatus 1. Figure 3 is a control block diagram of the exposure apparatus 1. As shown in Figure 3, the control unit 40 has a processor 41 such as a CPU (Central Processing Unit) and a memory 42. The control unit 40 is composed of, for example, one or more electrical circuit boards equipped with the processor 41 and the memory 42. However, the control unit 40 may be composed of a computer.

[0051] Memory 42 stores a program P for controlling the operation of the exposure apparatus 1 and managing the timing signal St, which will be described later. As shown in Figure 3, the control unit 40 is electrically connected to the main scanning mechanism 26, encoder 29, sub-scanning mechanism 27, laser oscillator 33, and spatial light modulator 34. The control unit 40 controls the operation of each of the above parts according to program P. As a result, the exposure process of the substrate 9 in the exposure apparatus 1 proceeds.

[0052] Furthermore, the exposure apparatus 1 has an operation unit 43 and a display unit 44. The operation unit 43 is, for example, a keyboard or mouse. The display unit 44 is, for example, a liquid crystal display. The control unit 40 is electrically connected to the operation unit 43 and the display unit 44. In addition, by using a touch panel display, the functions of the operation unit 43 and the display unit 44 may be realized by a single device.

[0053] <2. Control and Management of Spatial Light Modulators> Next, we will explain the control and timing signal St for driving the spatial light modulator 34.

[0054] Figure 4 is a conceptual block diagram showing the functions of the control unit 40 for controlling the spatial light modulator 34 and managing the timing signal St. As shown in Figure 4, the control unit 40 includes a pulse signal acquisition unit 51, a timing signal generation unit 52, a modulation control unit 53, a parameter storage unit 54, a movement speed determination unit 55, a timing signal measurement unit 56, and a measurement value storage unit 57. The functions of each of these units are realized by the operation of the processor 41 and memory 42 according to program P.

[0055] The pulse signal acquisition unit 51 acquires the pulse signal Sp output from the encoder 29. Figure 5 is a graph showing the waveform of the pulse signal Sp. When the substrate 9 moves in the main scanning direction at a constant speed, the encoder 29 outputs the pulse signal Sp at approximately constant intervals, as shown in Figure 5. However, due to mechanical or electrical errors in the encoder 29, the timing of some pulse signals Sp may be slightly off. This can cause the period of some pulse signals Sp to fluctuate. Such errors in the time axis direction of pulse signals Sp are called jitter errors.

[0056] A concrete example of the electrical errors mentioned above is the conversion error that occurs when converting the analog signal output from the encoder 29 to a digital signal. This conversion error includes errors that occur when reading the analog signal and errors corresponding to the time required for the conversion process. Conversion errors are often not reproducible. Therefore, it is difficult to accurately predict the magnitude and timing of jitter errors in advance.

[0057] The timing signal generation unit 52 generates a timing signal St for driving the spatial light modulator 34 based on the pulse signal Sp acquired by the pulse signal acquisition unit 51. Figure 6 is a graph showing the waveforms of the pulse signal Sp and the timing signal St. As shown in Figure 6, the timing signal generation unit 52 generates one timing signal St for a predetermined number of pulse signals Sp.

[0058] If the period of the pulse signal Sp is constant, then the period T of the timing signal St will also be constant. However, as mentioned above, if the pulse signal Sp contains jitter error, then an error will also occur in the period T of the timing signal St. Even if the jitter error of a single pulse signal Sp is very small, since one timing signal St is generated for each of the multiple pulse signals Sp, the jitter error can accumulate, and the error in the timing signal St may become large.

[0059] The modulation control unit 53 drives the spatial light modulator 34 based on the timing signal St output from the timing signal generation unit 52. The modulation control unit 53 switches the light modulation pattern of the spatial light modulator 34 at the timing when the timing signal St is generated. This makes it possible to switch the pattern of light irradiated onto the substrate 9 in accordance with the movement of the substrate 9 in the main scanning direction.

[0060] The parameter storage unit 54 stores various parameters related to the driving of the spatial light modulator 34. For example, the parameter storage unit 54 stores the number N of pulse signals Sp included in one period T of the timing signal St. The parameter storage unit 54 also stores the shortest period Tmin that the spatial light modulator 34 can drive, and the margin time dT added to the shortest period Tmin. The shortest period Tmin is the standard value of the spatial light modulator 34. The spatial light modulator 34 cannot switch patterns unless the interval is greater than or equal to the shortest period Tmin.

[0061] The margin time dT is a time that provides a margin in the actual drive cycle so that the period T of the timing signal St does not fall below the shortest period Tmin, even if the jitter error described above occurs. The user of the exposure apparatus 1 can set and change the margin time dT stored in the parameter storage unit 54 by operating the operation unit 43.

[0062] The movement speed determination unit 55 determines the movement speed V of the stage 20 in the main scanning direction. The movement speed determination unit 55 determines the movement speed V of the stage 20 by the main scanning mechanism 26 such that the period T of the timing signal St output from the timing signal generation unit 52 is the shortest period Tmin plus a margin time dT.

[0063] The timing signal measurement unit 56 measures the period T of the timing signal St output from the timing signal generation unit 52. As described above, if the period of the pulse signal Sp is constant, the timing signal St will also be generated with a constant period T. However, due to jitter errors in the pulse signal Sp, errors may occur in the period T of the timing signal St. The timing signal measurement unit 56 is capable of measuring the period T of the timing signal St, including such errors.

[0064] The measurement value storage unit 57 stores the measurement results of the timing signal measurement unit 56. The measurement value storage unit 57 may store all the periods T measured by the timing signal measurement unit 56. However, if all the periods T between a large number of timing signals St are stored, the storage capacity required for the timing signal measurement unit 56 will become very large. For this reason, the measurement value storage unit 57 may store only some of the periods T among the large number of periods T measured by the timing signal measurement unit 56.

[0065] For example, the measured value storage unit 57 may store only a portion of the multiple periods T measured by the timing signal measurement unit 56, including the minimum value. Alternatively, the measured value storage unit 57 may store only the minimum and maximum values ​​of the multiple periods T measured by the timing signal measurement unit 56. This reduces the storage capacity required for the measured value storage unit 57.

[0066] As shown in Figure 4, the control unit 40 can display the period T of the timing signal St stored in the measurement value storage unit 57 on the display unit 44. This allows the user of the exposure apparatus 1 to confirm whether the period T of the timing signal St generated based on the pulse signal Sp of the encoder 29 is appropriate.

[0067] From the viewpoint of processing efficiency of the exposure apparatus 1, a shorter period T of the timing signal St is desirable. However, if the period T of the timing signal St is made excessively short, the period T of the timing signal St will become shorter than the shortest period Tmin that the spatial light modulator 34 can drive. In addition, the period T of the timing signal St may fluctuate due to jitter errors. For this reason, in the exposure apparatus 1, it is important to manage the period T of the timing signal St so that, even when jitter errors are included, the actual period T of the timing signal St is greater than or equal to the shortest period Tmin, and as short as possible.

[0068] Figure 7 is a flowchart showing the procedure for managing the period T of the timing signal St. The process in Figure 7 is performed, for example, when the exposure apparatus 1 is started up, in order to appropriately set the period T of the timing signal St. However, the process in Figure 7 may also be performed while the exposure process is being carried out on the substrate 9 as a product, in order to check whether the period T of the timing signal St is appropriate.

[0069] As shown in Figure 7, the exposure apparatus 1 first acquires a pulse signal Sp from the encoder 29 (step ST1). Specifically, while the main scanning mechanism 26 moves the stage 20 in the main scanning direction, the pulse signal acquisition unit 51 acquires the pulse signal Sp output from the encoder 29.

[0070] Next, the timing signal generation unit 52 generates a timing signal St (step ST2). Specifically, the timing signal generation unit 52 generates one timing signal St every N counts of the pulse signal Sp. As a result, the timing signal St is output from the timing signal generation unit 52 with a period T corresponding to the pulse signal Sp.

[0071] Next, the timing signal measurement unit 56 measures the period T of the timing signal St (step ST3). The timing signal measurement unit 56 measures the period T between each of the multiple timing signals St that occur sequentially. The measured period T is then stored in the measurement value storage unit 57 (step ST4).

[0072] In step ST4, the measurement value storage unit 57 may store only the minimum and maximum values ​​of the multiple periods T measured in step ST3. By storing only a portion of the periods T instead of all of them, the storage capacity required for the measurement value storage unit 57 can be reduced. If the processing in steps ST7 to ST8, which will be described later, is omitted, only the minimum value of the multiple periods T measured in step ST3 may be stored in the measurement value storage unit 57.

[0073] Next, it is determined whether the minimum value of period T stored in the measurement value storage unit 57 is an appropriate value (step ST5). In step ST5, for example, the user of the exposure apparatus 1 determines whether it is appropriate by checking the minimum value of period T displayed on the display unit 44.

[0074] In step ST5, for example, if the minimum value of period T is greater than the shortest drivable period Tmin of the spatial light modulator 34, and the difference between the minimum value of period T and the shortest period Tmin is less than a predetermined amount, then the minimum value is determined to be appropriate (step ST5: Yes). On the other hand, if the minimum value of period T is greater than the shortest period Tmin, and the difference between the minimum value of period T and the shortest period Tmin is greater than or equal to a predetermined amount, or if the minimum value of period T is less than the shortest period Tmin, then the minimum value is determined to be inappropriate (step ST5: No).

[0075] If the minimum value of the period T stored in the measurement value storage unit 57 is determined to be inappropriate, the margin time dT is reset (step ST6). In step ST6, for example, the user of the exposure apparatus 1 resets the margin time dT stored in the parameter storage unit 54 by operating the operation unit 43.

[0076] For example, if the minimum value of the measured period T is greater than the shortest drivable period Tmin of the spatial light modulator 34, and the difference between the minimum value of period T and the shortest period Tmin is greater than or equal to a predetermined amount, the margin time dT stored in the parameter storage unit 54 is reduced. This shortens the period T of the timing signal St and improves the processing efficiency of the exposure apparatus 1. Also, if the minimum value of the measured period T is less than the shortest drivable period Tmin of the spatial light modulator 34, the margin time dT stored in the parameter storage unit 54 is increased. This ensures that the minimum value of the period T of the timing signal St becomes greater than the shortest period Tmin.

[0077] Thus, in the exposure apparatus 1 of this embodiment, the margin time dT stored in the parameter storage unit 54 can be reset based on the measured value of the period T of the timing signal St. Therefore, if the period T of the timing signal St is inappropriate, the margin time dT can be changed to optimize the period T of the timing signal St.

[0078] In step ST5, if it is determined that the minimum value of period T stored in the measurement value storage unit 57 is appropriate, then it is determined whether the maximum value of period T stored in the measurement value storage unit 57 is an appropriate value (step ST7). In step ST7, for example, the user of the exposure apparatus 1 determines whether it is appropriate by checking the maximum value of period T displayed on the display unit 44.

[0079] In step ST7, for example, if the maximum value of period T is less than a predetermined threshold, the maximum value is determined to be appropriate (step ST7: Yes). On the other hand, if the maximum value of period T is greater than or equal to the threshold, the minimum value is determined to be inappropriate (step ST7: No).

[0080] If the maximum value of period T stored in the measurement value storage unit 57 is determined to be inappropriate, there is a possibility that the encoder 29 is malfunctioning. For example, dirt may be adhering to the linear scale 291, preventing the sensor 292 from detecting some of the scale divisions 293. Therefore, if the maximum value of period T is determined to be inappropriate, the user of the exposure apparatus 1 checks whether there is any abnormality in the encoder 29 (step ST8).

[0081] As described above, in this exposure apparatus 1, the period T of the timing signal St for driving the spatial light modulator 34 can be measured by the timing signal measurement unit 56. This makes it possible to confirm whether the period T of the timing signal St generated based on the pulse signal Sp of the encoder 29 is appropriate.

[0082] Furthermore, the period T of the timing signal St can be optimized by adjusting the margin time dT based on the measured value of the period T of the timing signal St. This ensures that even if the pulse signal Sp output from the encoder 29 contains jitter errors, the period T of the timing signal St does not fall below the shortest drivable period Tmin of the spatial light modulator 34, and also prevents an excessive decrease in the processing efficiency of the exposure apparatus 1.

[0083] <3. Variant> Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.

[0084] Figure 8 is a block diagram conceptually showing the functions of the control unit 40 in one modified example. In the example of Figure 8, the control unit 40 differs from the above embodiment in that it has a margin setting unit 58. The margin setting unit 58 automatically resets the margin time dT stored in the parameter storage unit 54 based on the period T of the timing signal St output from the timing signal measurement unit 56. This allows the period T of the timing signal St to be automatically optimized without any user intervention.

[0085] The margin setting unit 58, for example, if the minimum value of the measured period T is greater than the shortest dmin drivable period of the spatial light modulator 34, and the difference between the minimum value of the period T and the shortest period Tmin is greater than or equal to a predetermined amount, reduces the margin time dT stored in the parameter storage unit 54. This shortens the period T of the timing signal St and improves the processing efficiency of the exposure apparatus 1. Conversely, if the minimum value of the measured period T is less than the shortest dmin drivable period of the spatial light modulator 34, the margin setting unit 58 increases the margin time dT stored in the parameter storage unit 54. This ensures that the minimum value of the period T of the timing signal St becomes greater than the shortest period Tmin.

[0086] Furthermore, the jitter error of the pulse signal Sp output from the encoder 29 tends to increase as the movement speed of the stage 20 in the main scanning direction decreases. For this reason, the margin setting unit 58 may vary the margin time dT during the exposure process so that the margin time dT increases as the movement speed of the stage 20 in the main scanning direction decreases.

[0087] Furthermore, without departing from the spirit of the present invention, some of the elements appearing in the above embodiments may be deleted, or known technologies may be added to the above embodiments. [Explanation of Symbols]

[0088] 1: Exposure device 9: Circuit board 10: Bass 15: Gantry 20: Stage 25: Movement mechanism 26: Main scanning mechanism 27: Sub-scanning mechanism 28: Intermediate plate 29: Encoder 30: Exposure area 31: Head 32: Illumination optical system 33: Laser Oscillator 34: Spatial Light Modulator 40: Control Unit 51: Pulse signal acquisition unit 52: Timing signal generation unit 53: Modulation Control Unit 54: Parameter storage unit 55: Movement speed determination section 56: Timing signal measurement unit 57: Measurement value storage unit 58: Margin Setting Section Sp: Pulse signal St: Timing signal T: Timing signal period

Claims

1. An exposure apparatus for exposing a pattern onto a substrate, A stage for holding the substrate, A moving mechanism for moving the aforementioned stage, An encoder that outputs a pulse signal in accordance with the movement of the aforementioned stage, Light source and A spatial light modulator modulates the light emitted from the light source and irradiates it onto the substrate, A timing signal generating unit that generates a timing signal based on the pulse signal output from the encoder, A modulation control unit that drives the spatial light modulator based on the timing signal, A timing signal measurement unit that measures the period of the aforementioned timing signal, An exposure apparatus equipped with the following features.

2. An exposure apparatus according to claim 1, A parameter storage unit that stores the shortest period during which the spatial light modulator can be driven and the margin time added to the shortest period, A movement speed determination unit determines the movement speed of the stage by the movement mechanism such that the period of the timing signal generated by the timing signal generation unit becomes the shortest period plus the margin time, Furthermore, An exposure apparatus capable of resetting the margin time stored in the parameter storage unit based on the period of the timing signal measured by the timing signal measurement unit.

3. An exposure apparatus according to claim 2, A margin setting unit automatically resets the margin time stored in the parameter storage unit based on the period of the timing signal measured by the timing signal measurement unit. An exposure device that is further equipped with these features.

4. An exposure apparatus according to any one of claims 1 to 3, Measurement value storage unit that stores the measurement results of the timing signal measurement unit Furthermore, The exposure apparatus wherein the measurement value storage unit stores only a portion of the multiple periods measured by the timing signal measurement unit, including the minimum value.

5. An exposure apparatus according to claim 4, The exposure apparatus wherein the measured value storage unit stores only the minimum and maximum values ​​of the multiple periods measured by the timing signal measurement unit.

6. In an exposure apparatus that exposes a pattern onto a substrate by irradiating it with light from a spatial light modulator while moving the substrate, a management method for managing the drive cycle of the spatial light modulator is provided, (a) A step of generating a timing signal for driving the spatial light modulator based on a pulse signal output from the encoder in response to the movement of the substrate, (b) A step of measuring the period of the timing signal, A management method having the following characteristics.

7. A management method according to claim 6, (c) A step of resetting the margin time to be added to the shortest drivable period of the spatial light modulator based on the period of the timing signal measured in step (b) above. A management method that further includes [the following].

8. A management method according to claim 7, A management method in which, in step (c), the margin time is reset so that the minimum value of the period of the timing signal measured in step (b) is greater than the shortest period.

9. A management method according to any one of claims 6 to 8, (d) A step of storing only a portion of the multiple periods measured by step (b) that include the minimum value. A management method that further includes [the following].

10. A management method according to claim 9, A management method in which, in step (d), only the minimum and maximum values ​​of the multiple periods measured in step (b) are stored.

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