Exposure device and exposure method

Abstract

The invention provides an exposure apparatus and an exposure method. Provided is an exposure device capable of forming an appropriate pattern by quickly coping with positional displacement of a stage due to deflection or the like. The exposure device (10) is provided with a plurality of exposure heads (20A-20C) and an encoder (30) composed of a pair of linear scales (32A, 32B) and a pair of scanning heads (34A, 34B). The encoder (30) is configured so as to detect inclination with respect to the Y direction (sub-scanning direction) caused by deflection or the like during the movement of the stage (12) during the exposure operation. An encoder signal correction processing circuit (60) outputs a correction encoder signal according to the arithmetic expression, and a DMD drive circuit of each exposure head reads out drawing data corresponding to the exposure position from each memory according to the correction encoder signal and drives the DMD.

Description

Technical Field

[0001] The present invention relates to an exposure device, and more particularly to a positional deviation of a drawing position caused by movement of a worktable. Background Art

[0002] In a maskless exposure device, exposure heads having a DMD (Digital Micromirror Device) as an array of light modulator elements are arranged at predetermined intervals along the sub-scanning direction. During exposure, the worktable on which the substrate is mounted is moved along the main scanning direction, and the projection area (exposure area) of each exposure head is moved (scanned) relative to the substrate. The DMD of each exposure head projects pattern light according to the drawing data (exposure data) corresponding to the position of the projection area.

[0003] The stage deflects during movement in the main scanning direction, causing positional deviation or tilt of the stage. The DMD of each exposure head is controlled based on the position information of the stage detected by an encoder, so exposure data needs to be corrected based on the tilt of the stage.

[0004] In order to detect the positional deviation of the worktable caused by deflection, etc., a method of correcting the drawing data using a laser interferometer has been proposed (see Patent Document 1). Here, the laser interferometer is arranged around the worktable, and the distance between the worktable and the laser interferometer is detected based on the reflected light from the worktable. The positional deviation of the worktable is detected based on the detected distance, and the drawing data is corrected.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-60990

[0006] When the positional deviation of the worktable is detected by using a laser interferometer, the drawing data is corrected while measuring the distance to the worktable, so the data correction process takes time and it is difficult to improve the tracking performance of projecting a suitable pattern light relative to the positional deviation of the worktable. This may result in a decrease in the resolution of the pattern formed on the substrate. Summary of the invention

[0007] Therefore, there is a demand for an exposure apparatus that can quickly cope with a positional deviation of a stage due to deflection or the like and form an appropriate pattern.

[0008] The exposure device of the present invention comprises: a plurality of exposure heads, which are arranged along a sub-scanning direction and respectively have an array of light modulation elements; a scanning mechanism, which moves a worktable on which a substrate is mounted along a main scanning direction so that the exposure areas of each of the plurality of exposure heads move relative to the substrate; and an encoder, which detects the position of the worktable during its movement.

[0009] Furthermore, the exposure device includes an exposure control unit that drives and controls the light modulator array of each exposure head according to the detected position of the worktable and the drawing data corresponding to the position of the exposure area of ​​each exposure head, thereby performing an exposure operation. For example, the exposure control unit includes a light modulator array drive circuit that reads the drawing data sequentially stored in the memory in each exposure head according to the encoder signal from the encoder and drives and controls the light modulator array.

[0010] In the present invention, the encoder is configured to detect the tilt of the worktable. Furthermore, the exposure operation of the exposure control unit is performed in accordance with the positional deviation of the exposure area of ​​each exposure head caused by the tilt of the worktable. For example, by correcting the encoder signal from the encoder according to the position of the exposure head for each exposure head, it is possible to read out the drawing data corresponding to the positional deviation of the exposure area caused by the tilt of the worktable, and drive and control the light modulation element array such as the DMD.

[0011] For example, the exposure device has an encoder signal correction processing circuit that corrects the encoder signal from the encoder in accordance with the positional deviation of the exposure area of ​​each exposure head caused by the tilt of the worktable. The light modulator array driving circuit reads out the drawing data sequentially stored in the memory in each exposure head according to the corrected encoder signal.

[0012] The encoder has various structures. For example, the encoder may be configured to include: a pair of linear scales parallel to each other along the main scanning direction; and a pair of scanning heads mounted on a workbench to read the scales of the pair of linear scales. The encoder signal for each exposure head is corrected based on the encoder signal output from the pair of scanning heads.

[0013] A pair of linear scales may be arranged on both sides of the workbench. For example, when the workbench is movable in the sub-scanning direction, the pair of linear scales may be arranged at a position outside the sub-scanning direction movement range of the workbench during the exposure operation in a manner capable of detecting the positions of the two side surfaces of the workbench during the exposure operation.

[0014] Furthermore, the encoder may be configured to detect the rotation angle of an axis perpendicular to a plane along the main scanning direction, the sub-scanning direction, and the main scanning direction and the sub-scanning direction. For example, the encoder has a linear scale arranged along the main scanning direction to match the middle position of the workbench along the sub-scanning direction.

[0015] In another aspect of the exposure method of the present invention, a worktable on which a substrate is mounted is moved along a main scanning direction relative to a plurality of exposure heads which are arranged along a sub-scanning direction and respectively have light modulator arrays, thereby causing exposure areas of the plurality of exposure heads to move relative to the substrate, and the light modulator arrays of each exposure head are driven and controlled based on drawing data corresponding to the position of the exposure area of ​​each exposure head, thereby performing an exposure action, wherein during the exposure action, while the worktable is moving, an encoder is used to detect the position of the worktable, including the tilt of the worktable, and the encoder signal output from the encoder is corrected so that the exposure action is performed in accordance with the positional offset of the exposure area of ​​each exposure head caused by the tilt of the worktable.

[0016] According to the present invention, it is possible to provide an exposure apparatus that can quickly cope with positional deviation of a stage due to deflection or the like and form an appropriate pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the exposure apparatus according to the first embodiment.

[0018] Figure 2 This is a diagram showing a part of the circuit configuration related to the correction of the encoder signal.

[0019] Figure 3 This is a diagram showing a part of the circuit configuration related to reading out drawing data.

[0020] Figure 4 It is a figure which shows the state which tilted the table.

[0021] Figure 5 It is a schematic structural diagram of the exposure apparatus according to the second embodiment.

[0022] Figure 6 This is a diagram showing a partial circuit configuration related to the correction process of the second embodiment.

[0023] Description of symbols

[0024] 10: exposure device; 12: workbench; 20A, 20B, 20C: exposure head; 21A, 21B, 21C: DMD drive circuit; 30: encoder; 32A, 32B: linear scale; 34A, 34B: scanning head; 50: control unit; 60: encoder signal correction processing circuit; 64: coordinate correction circuit. DETAILED DESCRIPTION

[0025] Hereinafter, the exposure apparatus according to the present embodiment will be described with reference to the drawings.

[0026] Figure 1 It is a schematic structural diagram of the exposure apparatus according to the first embodiment.

[0027] The exposure device 10 is configured as a maskless exposure device having a plurality of exposure heads 20. Here, there are three exposure heads 20A, 20B, and 20C. Each exposure head has a DMD drive circuit 21A, 21B, and 21C, an illumination optical system (not shown), a DMD (Digital Micromirror Device), and a projection optical system, and each exposure head is arranged at a predetermined interval along the sub-scanning direction.

[0028] Here, the exposure device 10 has a worktable 12 that supports a mounting table (not shown) on which a mounting substrate (not shown) is mounted. The worktable 12 can move in the main scanning direction and the sub-scanning direction, and can move along guide rails 15A and 15B extending in the main scanning direction and a guide rail (not shown) extending in the sub-scanning direction. Hereinafter, the main scanning direction is represented as the X direction, the sub-scanning direction is represented as the Y direction, and the position coordinates of the worktable 12 are represented as coordinates (X, Y).

[0029] The stage driving unit 80 controls the operation of the exposure device 10, and the actuator 18 moves the stage 12 in the X direction and the Y direction according to a control signal from the stage driving unit 80. The actuator 18 and the guide rails constitute a scanning mechanism based on the movement of the stage 12.

[0030] An exposure position detection unit (not shown) is provided near the end of the workbench 12. The exposure position detection unit includes a single photoelectric sensor and a pulse signal generating unit, and a light shielding unit that partially allows light to pass is provided above the exposure position detection unit. The control unit 50 calculates the exposure position, that is, the position of the substrate (workbench 12) relative to the exposure head, based on the signal sent from the exposure position detection unit. In addition, the structure of the exposure position detection unit is described in, for example, Japanese Patent Application Laid-Open No. 2015-142306, and a detailed description thereof is omitted.

[0031] The light outputted from a light source such as a laser not shown in the figure is projected onto a substrate mounted on a workbench via the above-mentioned illumination optical system, DMD, and projection optical system. In the DMD obtained by arranging rectangular micromirrors in a two-dimensional matrix, each micromirror is turned on / off according to a drive signal from a DMD drive circuit 21A, 21B, and 21C. The light reflected by the micromirror becomes a pattern light and is guided to the projection optical system, and is imaged on the surface of the photosensitive material of the substrate.

[0032] The exposure device 10 is connected to the CAD system via a network, and performs a series of data processing related to exposure by inputting design data such as CAD / CAM data sent from the CAD system. That is, data processing such as raster conversion processing for converting vector data such as CAD data into raster data and generating processing of drawing data (exposure data) that becomes a DMD drive signal based on the raster data is performed.

[0033] In the exposure operation, as the stage 12 moves in the X direction at a predetermined speed, the projection area based on the DMD of each exposure head 20A to 20C, that is, the exposure area, moves relatively on the substrate. When the DMD driving circuits 21A, 21B, and 21C receive an instruction to start exposure from the control unit 50, they detect the position of the stage 12 based on the encoder signal from the encoder 30, and drive and control the DMD of each exposure head based on the drawing data corresponding to the relative position of the exposure area. Here, multiple exposure (overlapping exposure) is performed at a predetermined exposure pitch, and a pattern is formed on the substrate as the stage 12 moves based on the scanning mechanism.

[0034] When the workbench 12 moves to the set position, the workbench 12 moves a predetermined distance in the Y direction. Then, the workbench 12 moves in the opposite direction (-X direction) to expose the scanning band adjacent to the scanning band where the pattern is formed. Figure 1 In FIG. 1 , the symbol B indicates the moving range of the stage 12 along the Y direction during the exposure operation.

[0035] The encoder 30 is configured to detect the inclination of the table 12 caused by the deflection or the like caused by the movement of the table 12. The encoder 30 includes a pair of linear scales 32A and 32B and a pair of scanning heads 34A and 34B.

[0036] The scanning heads 34A and 34B are mounted on the side surfaces 12S1 and 12S2 along the X direction (main scanning direction) of the table 12 so as to be able to read the scales of the linear scales 32A and 32B, respectively. The linear scales 32A and 32B are parallel to each other along the X direction. In addition, the scanning heads 34A and 34B are mounted so that the mounting positions along the X direction are the same, that is, the X coordinates (for example, the center positions) are consistent.

[0037] Here, the encoder 30 is configured to optically read the scales of the linear scales 32A and 32B. When the stage 12 moves in the X direction in conjunction with the exposure operation, the scanning heads 34A and 34B output encoder signals (e.g., pulse signals). The encoder signal correction processing circuit 60 obtains (calculates) the position coordinates of the stage 12 and the positional deviation of the exposure position of each exposure head caused by the tilt of the stage 12 caused by deflection, etc., based on the encoder signals.

[0038] The pair of linear scales 32A and 32B are arranged outside the sub-scanning direction movement range B of the stage 12 so as to detect the inclination of the stage 12 during the exposure operation. The scanning heads 34A and 34B are mounted on the stage 12 so as to read the scales, that is, detect reflected light, regardless of the Y-direction movement of the stage 12.

[0039] Furthermore, the exposure device 10 includes a linear encoder (not shown) that detects the position coordinates of the stage 12 in the Y direction (sub-scanning direction).

[0040] Figure 2 : is a diagram showing a part of the circuit configuration related to the correction of the encoder signal.

[0041] The encoder signal correction processing circuit 60, which corrects the encoder signal output from the encoder 30, calculates the inclination of the workbench 12 relative to the sub-scanning direction, that is, the position offset of the exposure position of each exposure head, based on the encoder signal sent from a pair of linear scales 32A and 32B, and outputs a correction encoder signal corresponding to the position offset.

[0042] The encoder signal correction processing circuit 60 includes signal conversion circuits 66A and 66B that receive encoder signals and perform signal processing conversion, a calculation circuit 62, and signal conversion circuits 67A, 67B, and 67C that output correction encoder signals. The calculation circuit 62 includes encoder counters 63A and 63B, a coordinate correction circuit 64, and a calculation parameter input unit 65.

[0043] The coordinate correction circuit 64 calculates the positional deviation of the exposure area of ​​each exposure head corresponding to the tilt of the worktable 12, that is, the positional deviation amount relative to the position of the exposure area when the tilt does not occur, based on the encoder signal sent from the scanning head 34A, 34B. Here, the displacement along the X direction relative to the center position of the exposure area is calculated. Based on the calculated value, the encoder signal for the exposure area of ​​each exposure head is corrected and output from the signal conversion circuit 67A, 67B, 67C.

[0044] Figure 3 2 is a diagram showing a part of the circuit configuration related to the reading of drawing data. Here, the reading of drawing data by the DMD driving circuit 21A is described. The same is true for the other DMD driving circuits 21B and 21C.

[0045] The drawing data (raster data) for the exposure head 20A generated by a series of data processing is temporarily stored in the memory 70 in the DMD drive circuit 21A. The exposure heads 20B and 20C are also configured in the same manner.

[0046] The drawing data in the memory 70 is stored in the order of the drawn patterns (reading order). The memory read control unit 73 reads the drawing data from the memory 70 in sequence, and sends a drive signal corresponding to the drawing data to the DMD via the data transmission processing circuit 72. The read timing control circuit 71 receives the encoder signal and instructs the memory read control unit 73 to read the drawing data.

[0047] As described above, the encoder signal correction processing circuit 60 generates and outputs a correction encoder signal based on the positional deviation of the exposure area of ​​each exposure head caused by the tilt of the worktable 12. Therefore, the drawing data temporarily stored in each memory of each exposure head is read out based on the correction encoder signal. Therefore, the exposure operation is performed using the drawing data corresponding to the tilt of the worktable 12 caused by the deflection, etc.

[0048] Figure 4 12 is a diagram showing a state where the table 12 is tilted. When the table 12 is not tilted, the scanning heads 34A and 34B (see Figure 1 ) The output of the encoder signal outputted by the exposure head 20 does not need to be corrected, and the exposure operation is performed according to the specified count value. That is, the position coordinates of the exposure area of ​​each exposure head 20 have no positional deviation in the X direction. Figure 4 The position coordinates of the exposure area EA of the exposure head 20C shown do not differ from the position coordinates of the exposure areas of the other exposure heads.

[0049] On the other hand, when the stage 12 is tilted by θ due to deflection or the like during movement, the positions of the exposure regions of the exposure heads 20A to 20C are different from each other in the X direction. Figure 4 In FIG. 1 , the positional deviation of the exposure region of the exposure head 20A along the X direction is represented by ΔE.

[0050] In the present embodiment, coordinates are calculated in consideration of the positional deviation amount of the exposure region of each exposure head by the following formula (1).

[0051] En=(Er+El) / 2+((Er-El) / W)×(Yn-Ys)……(1)

[0052] n represents the number assigned to the exposure head (in Figure 1In the case of, 1, 2, and 3 are assigned to the exposure heads 20A, 20B, and 20C, respectively, and En represents the correction encoder coordinate for the exposure head n. Furthermore, El represents the position coordinate of the linear scale 32A based on the encoder signal (count value) output from the scanning head 34A, and Er represents the position coordinate of the linear scale 32B based on the encoder signal output from the scanning head 34B. Furthermore, Yn represents the Y coordinate of the exposure head n, Ys represents the Y coordinate of the workbench 12, and W represents the distance between the pair of linear scales 32A and 32B (refer to Figure 4 ).

[0053] In addition, Ys indicating the Y coordinate of the table 12 is measured by the above-mentioned linear encoder (not shown). Furthermore, the Y coordinate of the exposure head n is based on the detection result of the exposure position detection unit. Coordinate information other than the position coordinate information of the table 12 based on the encoder 30 is obtained based on the information from the computer 90 (see Figure 2 ) input information.

[0054] Figure 2 The coordinate correction circuit 64 shown in the figure obtains the correction encoder coordinates corresponding to the positional deviation of the exposure area of ​​each exposure head by performing the calculation processing based on the above-mentioned formula (1).

[0055] Thus, the exposure device 10 of the present embodiment has a plurality of exposure heads 20A to 20C, and has an encoder 30 composed of a pair of linear scales 32A, 32B and a pair of scanning heads 34A, 34B. The encoder 30 is configured to be able to detect the position of the workbench including the tilt relative to the Y direction (sub-scanning direction) caused by deflection, etc. during the movement of the workbench 12 in the exposure operation. Therefore, with respect to the relative position of the exposure area of ​​each exposure head, the position offset of the exposure area caused by the tilt of the workbench 12 is determined. The encoder signal correction processing circuit 60 outputs a correction encoder signal according to the above formula (1). The DMD driving circuits 21A, 21B, and 21C read out the drawing data corresponding to the exposure position of each exposure head from each memory according to the correction encoder signal, and drive the corresponding DMD.

[0056] During the exposure operation, the encoder 30 can be used to directly detect the tilt of the worktable 12, so the position deviation of the exposure area of ​​each exposure head can be quickly obtained based on the calculation process. In particular, the encoder signal correction processing circuit 60 directly obtains and corrects the encoder signal based on the encoder signal, so the calculation process can be quickly performed. In particular, unlike the laser interferometer, for the deflection generated during the exposure operation, the exposure operation that matches the position of each exposure area can be performed in real time, which can improve the tracking performance.

[0057] Furthermore, since the position coordinates of the table 12 along the X direction and the inclination of the table 12 are detected simultaneously, there is no need to prepare a separate measuring instrument for inclination detection such as a laser interferometer, and there is no need to worry about being affected by atmospheric fluctuations like a laser interferometer.

[0058] Furthermore, while the encoder signal is corrected, the drawing data is not corrected in relation to its position coordinates, but the timing of reading the drawing data from each memory is adjusted (corrected). In this way, the drawing data is read out and the drive control of the DMD is performed in accordance with the positional deviation of the exposure area of ​​each exposure head, and the drawing data itself is not corrected, so that the data processing time for dealing with the positional deviation is further shortened, and the tracking performance of the deflection, etc. can be further improved.

[0059] Next, use Figure 5 The exposure apparatus according to the second embodiment is described. In the second embodiment, an encoder capable of multi-dimensionally measuring coordinates is used.

[0060] Figure 5 It is a schematic structural diagram of the exposure apparatus according to the second embodiment.

[0061] The exposure device 100 has an encoder 130 capable of measuring multi-dimensional position coordinates. The encoder 130 has a linear scale 132 and a scanning head (not shown), and the scanning head is mounted on the bottom surface of the workbench 12. The encoder 130 is arranged along the X direction and is arranged to match the middle position of the workbench 12 in the Y direction.

[0062] Here, the scanning head of the encoder 130 is configured to detect the rotation angle about the X direction, the Y direction, and the axis perpendicular to the XY plane (for example, a combination of two scanning heads). The encoder signal correction processing circuit 160 corrects the encoder signal based on the encoder signal from the encoder 130 .

[0063] Figure 6 It is a diagram showing a part of the circuit configuration related to the correction process of the second embodiment.

[0064] The encoder signal correction processing circuit 160 includes signal conversion circuits 166A to 166C, a calculation circuit 162, and signal conversion circuits 167A to 167C that output correction encoder signals. The calculation circuit 162 includes encoder counters 163A, 163B, and 163C, a coordinate correction circuit 164, a calculation parameter input unit 165, and a rotation angle calculation circuit 169.

[0065] In the second embodiment, the correction encoder coordinates are obtained by the following equation (2).

[0066] En=Ex+R(Yn-Ys)……(2)

[0067] Here, Ex and Ys respectively represent the position coordinates of the worktable 12 obtained from the encoder signal output from the encoder 130. And R represents the rotation angle of the worktable 12 obtained from the encoder signal output from the encoder 130. The rotation angle is obtained in the rotation angle calculation circuit 169. About n, En, and Yn, it is the same as the first embodiment.

[0068] Thus, in the second embodiment, the encoder 130 capable of detecting multi-dimensional position information is used to simultaneously detect the X and Y coordinates of the table 12 and the tilt of the table 12. By configuring the encoder 130 more simply, the data processing time can be shortened.

[0069] The above-mentioned equations (1) and (2) are derived from the configuration structure of the linear scale, the position of the exposure head, etc. In the case of an exposure device different from the first and second embodiments, the equations can be derived in accordance with the structure of the exposure device. In addition, the structure of the encoder is not limited to the structure shown in the first and second embodiments, as long as the structure has a linear scale and a scanning head in a manner that can generate the tilt of the worktable 12 and the encoder correction signal.

Claims

1. An exposure device, characterized in that: The exposure device has: A plurality of exposure heads, each of which is arranged along a sub-scanning direction and has a light modulation element array; A scanning mechanism that moves a workbench on which a substrate is mounted along a main scanning direction so that exposure areas of each of the plurality of exposure heads move relative to the substrate; an encoder that detects the position of the worktable during movement of the worktable; as well as an exposure control unit that drives and controls the light modulation element array of each exposure head according to the detected position of the worktable and the drawing data corresponding to the position of the exposure area of ​​each exposure head, thereby performing an exposure operation; The encoder is configured to detect the tilt of the table. The exposure control unit performs an exposure operation in accordance with a positional deviation of an exposure region of each exposure head caused by the tilt of the stage.

2. The exposure device according to claim 1, characterized in that The exposure control unit includes a light modulator array drive circuit, which reads out drawing data sequentially stored in the memory in each exposure head according to the encoder signal from the encoder and drives and controls the light modulator array. The exposure device further includes an encoder signal correction processing circuit that corrects an encoder signal from the encoder in accordance with a positional deviation of an exposure area of ​​each exposure head caused by the tilt of the worktable. The light modulator array driving circuit reads out the drawing data sequentially stored in the memory in each exposure head according to the corrected encoder signal.

3. The exposure device according to claim 1 or 2, characterized in that: The encoder has: a pair of linear scales, the pair of linear scales being parallel to each other along a main scanning direction; and A pair of scanning heads, the pair of scanning heads are mounted on the workbench to read the scales of a pair of linear scales, The encoder signal for each exposure head is corrected based on the encoder signal output from the pair of scanning heads.

4. The exposure device according to claim 3, characterized in that The workbench can move along the secondary scanning direction, The pair of linear scales are arranged at positions outside a movement range of the stage in the sub-scanning direction during the exposure operation so as to be able to detect positions of both side surfaces of the stage during the exposure operation.

5. The exposure device according to claim 1 or 2, characterized in that: The encoder is capable of detecting a rotation angle with respect to a main scanning direction, a sub scanning direction, and an axis perpendicular to a plane along the main scanning direction and the sub scanning direction.

6. The exposure device according to claim 5, characterized in that The encoder has a linear scale arranged along the main scanning direction so as to match a middle position of the stage along the sub-scanning direction.

7. An exposure method, The working table on which the substrate is mounted is moved in the main scanning direction relative to a plurality of exposure heads arranged in the sub-scanning direction and each having an array of light modulator elements, thereby causing the exposure areas of the plurality of exposure heads to move relative to the substrate. The light modulation element array of each exposure head is driven and controlled according to the drawing data corresponding to the position of the exposure area of ​​each exposure head, thereby performing an exposure operation. It is characterized in that During the exposure operation, the position of the stage including the inclination of the stage is detected by an encoder while the stage is moving. The encoder signal output from the encoder is corrected so that an exposure operation is performed in accordance with a positional deviation of an exposure region of each exposure head caused by the tilt of the stage.

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