Exposure device and exposure method

Abstract

To provide an exposure device which quickly copes with positional deviation of a stage caused by yawing and can form an appropriate pattern.SOLUTION: An exposure device 10 includes a plurality of exposure heads 20A to 20C, and an encoder 30 composed of a pair of linear scales 32A and 32B, and a pair of scanning heads 34A and 34B. The encoder 30 is configured to be capable of detecting inclination in a Y direction (sub-scanning direction) caused by yawing, while a stage 12 is moved by exposure operation. An encoder signal correction processing circuit 60 outputs a correction encoder signal on the basis of an operational expression, and a DVD driving circuit of each of the exposure heads reads out drawing data according to the exposure position from each memory, on the basis of the correction encoder signal, and drives a DMD.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an exposure apparatus, and more particularly to a positional deviation of a drawing position that occurs with the movement of a stage. [Background technology]

[0002] In a maskless exposure apparatus, exposure heads each equipped with a DMD as an optical modulation element array are arranged in a line at a predetermined interval along the sub-scanning direction. During exposure, the stage on which the substrate is placed 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 a pattern light based on drawing data (exposure data) corresponding to the position of the projection area.

[0003] While the stage is moving in the main scanning direction, yawing and other factors can occur, causing the stage to shift in position, i.e., tilt. The DMD of each exposure head is controlled based on stage position information detected by an encoder or other device, so the exposure data needs to be corrected according to the stage tilt.

[0004] A method has been proposed in which a laser interferometer is used to correct drawing data in order to detect positional deviation of the stage caused by yawing or the like (see Patent Document 1). In this method, a laser interferometer is arranged around the stage, and the distance between the stage and the laser interferometer is detected based on the light reflected from the stage. Positional deviation of the stage is detected from the detected distance, and the drawing data is corrected. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-60990 A Summary of the Invention [Problem to be solved by the invention]

[0006] When detecting stage misalignment using a laser interferometer, the drawing data is corrected while measuring the distance to the stage, so the data correction process takes time and it is difficult to improve the tracking ability to project the appropriate pattern light in response to the stage misalignment, which may result in a decrease in the resolution of the pattern formed on the substrate.

[0007] Therefore, there is a need to provide an exposure apparatus that can quickly deal with stage positional deviations caused by yawing or the like and form an appropriate pattern. [Means for solving the problem]

[0008] The exposure apparatus of the present invention comprises a plurality of exposure heads, each of which has an array of light modulation elements and is arranged along the sub-scanning direction, a scanning mechanism that moves a stage on which a substrate is placed along the main scanning direction and moves the exposure area of ​​each of the plurality of exposure heads relative to the substrate, and an encoder that detects the position of the stage while the stage is moving.

[0009] The exposure apparatus also includes an exposure control unit that drives and controls the light modulation element array of each exposure head based on drawing data corresponding to the position of the exposure area of ​​each exposure head from the detected position of the stage, and performs exposure operation. For example, the exposure control unit includes a light modulation element array drive circuit that reads out drawing data sequentially stored in the memory in each exposure head based on an encoder signal from an encoder, and drives and controls the light modulation element array.

[0010] In the present invention, the encoder is configured to detect the tilt of the stage. Then, the exposure control unit performs an exposure operation in accordance with the positional deviation of the exposure area of ​​each exposure head caused by the tilt of the stage. For example, by correcting the encoder signal from the encoder for each exposure head according to the exposure head position, drawing data corresponding to the positional deviation of the exposure area caused by the tilt of the stage can be read out and a light modulation element array such as a DMD can be driven and controlled.

[0011] For example, the exposure apparatus includes 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 stage. The light modulation element array drive circuit reads out the drawing data sequentially stored in the memory in each exposure head based on the corrected encoder signal.

[0012] The encoder may have various configurations. For example, the encoder may have a pair of linear scales parallel to each other along the main scanning direction, and a pair of scanning heads that are attached to the stage and read the graduations of the pair of linear scales. Then, the encoder signal for each exposure head is corrected based on the encoder signal output from the pair of scanning heads.

[0013] The pair of linear scales can be disposed on both sides of the stage. For example, if the stage is movable along the sub-scanning direction, the pair of linear scales can be disposed outside the range of movement of the stage in the sub-scanning direction during the exposure operation so that the positions of both side surfaces of the stage can be detected during the exposure operation.

[0014] The encoder may be configured as an encoder capable of detecting a rotation angle with respect to an axis perpendicular to the scanning direction, the sub-scanning direction, and a plane along the main scanning direction and the sub-scanning direction. For example, the encoder may include a linear scale arranged along the main scanning direction in accordance with a middle position of the stage along the sub-scanning direction.

[0015] Another aspect of the exposure method of the present invention is an exposure method in which a stage on which a substrate is placed is moved along the main scanning direction relative to a plurality of exposure heads, each of which is equipped with an array of light modulation elements and arranged along the sub-scanning direction, thereby moving the exposure area of ​​each of the plurality of exposure heads relative to the substrate, and driving and controlling the light modulation element array of each exposure head based on drawing data corresponding to the position of the exposure area of ​​each exposure head, thereby performing an exposure operation.While the stage moves during the exposure operation, an encoder detects the position of the stage, including the inclination of the stage, and the encoder signal output from the encoder is corrected so that the exposure operation is performed in accordance with the positional deviation of the exposure area of ​​each exposure head due to the inclination of the stage. Effect of the Invention

[0016] According to the present invention, it is possible to provide an exposure apparatus that can quickly deal with a positional deviation of a stage caused by yawing or the like and form an appropriate pattern. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic configuration diagram of an exposure apparatus according to a first embodiment. [Diagram 2] FIG. 4 is a diagram showing a partial circuit configuration related to correction of an encoder signal. [Diagram 3] FIG. 2 is a diagram showing a partial circuit configuration related to reading out drawing data. [Figure 4] FIG. 13 is a diagram showing a state in which the stage is tilted. [Diagram 5] FIG. 11 is a schematic configuration diagram of an exposure apparatus according to a second embodiment. [Figure 6] FIG. 11 is a diagram showing a partial circuit configuration related to correction processing in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The exposure apparatus according to the present embodiment will be described below with reference to the drawings.

[0019] FIG. 1 is a schematic diagram of an exposure apparatus according to the first embodiment.

[0020] The exposure apparatus 10 is configured as a maskless exposure apparatus equipped with a plurality of exposure heads 20. Here, three exposure heads 20A, 20B, and 20C are provided. Each exposure head includes a DMD driving circuit 21A, 21B, or 21C, an illumination optical system (not shown), a DMD (Digital Micromirror Device), and a projection optical system, and is arranged side by side at a predetermined interval along the sub-scanning direction.

[0021] Exposure apparatus 10 includes a stage 12 that supports a table (not shown) on which a substrate (not shown here) is placed. Stage 12 is movable in the main scanning direction and the sub-scanning direction, and is movable along guide rails 15A and 15B that extend along the main scanning direction and a guide rail (not shown) that extends along the sub-scanning direction. In the following, the main scanning direction is defined as the X direction, the sub-scanning direction is defined as the Y direction, and the position coordinates of stage 12 are expressed as (X, Y) coordinates.

[0022] The stage driving unit 80 controls the operation of the exposure apparatus 10, and the actuator 18 moves the stage 12 in the X and Y directions in response to a control signal from the stage driving unit 80. The actuator 18, together with the above-mentioned guide rails, constitutes a scanning mechanism that moves the stage 12.

[0023] An exposure position detector (not shown) is provided near the end of the stage 12. The exposure position detector includes a single photosensor and a pulse signal generator, and a light-shielding section that partially transmits light is provided above the exposure position detector. The control section 50 calculates the exposure position, i.e., the position of the substrate (stage 12) relative to the exposure head, based on the signal sent from the exposure position detector. The configuration of the exposure position detector is described in, for example, JP 2015-142306 A, and detailed description thereof will be omitted.

[0024] Light output from a light source such as a laser (not shown) is projected onto a substrate placed on a table via the illumination optical system, DMD, and projection optical system described above. In the DMD, which has rectangular micromirrors arranged two-dimensionally in a matrix, each micromirror is controlled to be turned on / off in response to a drive signal from DMD drive circuits 21A, 21B, and 21C. The light reflected by the micromirrors becomes a pattern light and is guided to the projection optical system, where it is imaged on the surface of the photosensitive material of the substrate.

[0025] The exposure apparatus 10 is connected to a CAD system via a network, and executes 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 generation processing of drawing data (exposure data) that becomes a DMD drive signal based on the raster data is executed.

[0026] In the exposure operation, as the stage 12 moves in the X direction at a predetermined speed, the exposure areas, which are the projection areas of the DMDs of the exposure heads 20A-20C, move relatively on the substrate. When the DMD driving circuits 21A, 21B, 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 DMDs of the exposure heads based on drawing data corresponding to the relative positions of the exposure areas. Here, multiple exposure (overlapping exposure) is performed at a predetermined exposure pitch, and a pattern is formed on the substrate as the stage 12 is moved by the scanning mechanism.

[0027] When the stage 12 moves to a predetermined position, the stage 12 moves a predetermined distance in the Y direction. Then, the stage 12 moves in the reverse direction (-X direction) so as to expose a scan band adjacent to the patterned scan band. In FIG. 1, the movement range of the stage 12 in the Y direction during the exposure operation is indicated by the symbol B.

[0028] The encoder 30 is configured to be able to detect the inclination of the stage 12 caused by yawing or the like that occurs with the movement of the stage 12. The encoder 30 is composed of a pair of linear scales 32A, 32B and a pair of scanning heads 34A, 34B.

[0029] The scanning heads 34A and 34B are mounted on the side surfaces 12S1 and 12S2 of the stage 12 along the X direction (main scanning direction) so that the scales of the linear scales 32A and 32B can be read, respectively. The linear scales 32A and 32B are parallel to each other along the X direction. The scanning heads 34A and 34B are mounted at the same mounting position along the X direction, that is, so that the X coordinates (for example, of the center positions) match.

[0030] The encoder 30 is configured to optically read the graduations of the linear scales 32A and 32B. When the stage 12 moves in the X direction in accordance 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 based on the encoder signals, as well as the positional deviation of the exposure position of each exposure head caused by the inclination of the stage 12 due to yawing or the like.

[0031] The pair of linear scales 32A, 32B are disposed outside the sub-scanning direction movement range B of the stage 12 so as to be able to detect the inclination of the stage 12 during exposure operation. The scanning heads 34A, 34B are attached to the stage 12 so as to be able to read the scales regardless of the movement of the stage 12 in the Y direction, i.e., to be able to detect reflected light.

[0032] Furthermore, the exposure apparatus 10 is equipped with a linear encoder (not shown) that detects the position coordinates of the stage 12 in the Y direction (sub-scanning direction).

[0033] FIG. 2 is a diagram showing a partial circuit configuration related to correction of an encoder signal.

[0034] An encoder signal correction processing circuit 60, which corrects the encoder signal output from the encoder 30, calculates the inclination of the stage 12 with respect to the sub-scanning direction, i.e., the amount of positional deviation of the exposure position of each exposure head, based on the encoder signals sent from a pair of linear scales 32A, 32B, and outputs a corrected encoder signal according to the amount of positional deviation.

[0035] The encoder signal correction processing circuit 60 includes signal conversion circuits 66A and 66B that receive and process and convert encoder signals, an arithmetic circuit 62, and signal conversion circuits 67A, 67B, and 67C that output corrected encoder signals. The arithmetic circuit 62 includes encoder counters 63A and 63B, a coordinate correction circuit 64, and an arithmetic parameter input unit 65.

[0036] Based on the encoder signals sent from the scan heads 34A and 34B, the coordinate correction circuit 64 calculates the positional deviation of the exposure area of ​​each exposure head according to the tilt of the stage 12, i.e., the amount of positional deviation from the position of the exposure area when no tilt occurs. Here, the displacement along the X direction relative to the center position of the exposure area is calculated. Based on this calculated value, corrected encoder signals obtained by correcting the encoder signals for the exposure area of ​​each exposure head are output from the signal conversion circuits 67A, 67B, and 67C.

[0037] 3 is a diagram showing a part of the circuit configuration related to drawing data reading. Here, drawing data reading in DMD driving circuit 21A is explained. The same applies to the other DMD driving circuits 21B and 21C.

[0038] Drawing data for exposure head 20A (raster data) generated by a series of data processing is temporarily stored in memory 70 in DMD driving circuit 21A. Exposure heads 20B and 20C are configured in a similar manner.

[0039] The drawing data in the memory 70 is stored in the order of the patterns to be drawn (read order). The memory read control unit 73 sequentially reads the drawing data from the memory 70, and sends a drive signal according to the drawing data to the DMD via the data transfer 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.

[0040] As described above, the encoder signal correction processing circuit 60 generates and outputs a correction encoder signal based on the amount of positional deviation of the exposure area of ​​each exposure head caused by the tilt of the stage 12. Therefore, the drawing data temporarily stored in each memory for each exposure head is read out based on the correction encoder signal. Therefore, the exposure operation is performed using drawing data corresponding to the tilt of the stage 12 caused by yawing or the like.

[0041] Fig. 4 is a diagram showing a tilted state of the stage 12. When the stage 12 is not tilted, there is no need to correct the output of the encoder signals output from the scanning heads 34A, 34B (see Fig. 1), and the exposure operation is performed according to a predetermined count number. That is, the position coordinates of the exposure area of ​​each exposure head 20 are not misaligned in the X direction, and there is no difference between the position coordinates of the exposure area EA of the exposure head 20C shown in Fig. 4 and the position coordinates of the exposure areas of the other exposure heads.

[0042] On the other hand, if yawing or the like occurs while stage 12 is moving, causing a tilt θ in stage 12, the positions of the exposure areas of exposure heads 20A to 20C will differ from one another in the X direction. In Fig. 4, the positional deviation in the X direction of the exposure area relative to exposure head 20A is represented as ΔE.

[0043] In this embodiment, the coordinates taking into consideration the amount of positional deviation of the exposure area of ​​each exposure head are calculated using the following equation (1). E = (Er + E) / 2 + ((Er-El) / W) x (Yn-Ys) (1)

[0044] n is the number given to the exposure head (in the case of FIG. 1, 1, 2, and 3 are given to the exposure heads 20A, 20B, and 20C, respectively), and En represents the corrected encoder coordinate for the exposure head n. Furthermore, El represents the position coordinate based on the encoder signal (count number) output from the scanning head 34A of the linear scale 32A, and Er represents the position coordinate based on the encoder signal output from the scanning head 34B of the linear scale 32B. Furthermore, Yn represents the Y coordinate of the exposure head n, Ys represents the Y coordinate of the stage 12, and W represents the distance between the pair of linear scales 32A and 32B (see FIG. 4).

[0045] Incidentally, Ys, which represents the Y coordinate of the stage 12, is measured by the linear encoder (not shown) described above. 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 stage 12 from the encoder 30 is based on input information from the computer 90 (see FIG. 2).

[0046] The coordinate correction circuit 64 shown in FIG. 2 performs calculation processing based on the above formula (1) to find corrected encoder coordinates according to the positional deviation of the exposure area of ​​each exposure head.

[0047] Thus, the exposure apparatus 10 of this embodiment includes a plurality of exposure heads 20A-20C, and also includes an encoder 30 consisting 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 stage position including the inclination in the Y direction (sub-scanning direction) caused by yawing or the like while the stage 12 moves in the exposure operation. Therefore, the positional deviation of the exposure area caused by the inclination of the stage 12 is specified with respect to the relative position of the exposure area of ​​each exposure head. The encoder signal correction processing circuit 60 outputs a correction encoder signal based on the above formula (1). The DMD driving circuits 21A, 21B, 21C read out drawing data corresponding to the exposure position of each exposure head from each memory based on the correction encoder signal, and drive the corresponding DMD.

[0048] During the exposure operation, the inclination of the stage 12 can be directly detected by the encoder 30, so the positional deviation of the exposure area of ​​each exposure head can be quickly found by calculation. In particular, the encoder signal correction processing circuit 60 can directly find a corrected encoder signal from the encoder signal, so calculation processing can be performed quickly. In particular, unlike a laser interferometer, it is possible to execute an exposure operation aligned with the position of each exposure area in real time in response to yawing that occurs during the exposure operation, and tracking performance can be improved.

[0049] In addition, since the tilt of the stage 12 is detected while also detecting the position coordinate of the stage 12 in the X direction, there is no need to prepare a separate measuring device for tilt detection, such as a laser interferometer, and there is also no need to worry about being affected by atmospheric fluctuations, as is the case with a laser interferometer.

[0050] Furthermore, while the encoder signal is corrected, the position coordinates of the drawing data are not corrected, and the timing of reading the drawing data from each memory is adjusted (corrected). In this way, the drawing data is read in accordance with the positional deviation of the exposure area of ​​each exposure head, and the DMD drive control is performed, and correction processing is not performed on the drawing data itself, so that the data processing time required to deal with positional deviations is further shortened, and the ability to follow yawing and the like can be further improved.

[0051] Next, an exposure apparatus according to a second embodiment will be described with reference to Fig. 5. In the second embodiment, an encoder capable of measuring coordinates in multiple dimensions is used.

[0052] FIG. 5 is a schematic configuration diagram of an exposure apparatus according to the second embodiment.

[0053] The exposure apparatus 100 is equipped with an encoder 130 capable of measuring multi-dimensional position coordinates. The encoder 130 includes a linear scale 132 and a scanning head (not shown), and the scanning head is attached to the bottom surface of the stage 12. The encoder 130 is disposed along the X direction, and is aligned with the middle position of the stage 12 in the Y direction.

[0054] The scanning head of the encoder 130 is configured to be able to detect the rotation angle with respect to the axis perpendicular to the X direction, the Y direction, and the XY plane (for example, a configuration in which two scanning heads are combined). The encoder signal correction processing circuit 160 corrects the encoder signal based on the encoder signal from the encoder 130.

[0055] FIG. 6 is a diagram showing a partial circuit configuration related to the correction process in the second embodiment.

[0056] The encoder signal correction processing circuit 160 includes signal conversion circuits 166A-166C, an arithmetic circuit 162, and signal conversion circuits 167A-167C that output corrected encoder signals. The arithmetic 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.

[0057] In the second embodiment, the corrected encoder coordinates are calculated by the following equation (2). E = E + R (Yn - Ys) (2) Here, Ex and Ys respectively represent the position coordinates of the stage 12 obtained from the encoder signal output from the encoder 130. Furthermore, R represents the rotation angle of the stage 12 obtained from the encoder signal output from the encoder 130. The rotation angle is obtained in a rotation angle calculation circuit 169. n, En, and Yn are the same as in the first embodiment.

[0058] In this way, in the second embodiment, by using an encoder 130 capable of detecting multi-dimensional position information, the tilt of the stage 12 is detected simultaneously along with the X and Y coordinates of the stage 12. By configuring a simpler encoder 130, the data processing time can be shortened.

[0059] The above-mentioned arithmetic expressions (1) and (2) are derived based on the arrangement of the linear scale, the position of the exposure head, etc., and in the case of an exposure apparatus different from those of the first and second embodiments, the arithmetic expressions may be derived according to the configuration of the exposure apparatus. Furthermore, the configuration of the encoder is not limited to the configuration shown in the first and second embodiments, and may be any configuration that includes a linear scale and a scanning head so as to be able to detect the tilt of the stage 12 and generate an encoder correction signal. [Explanation of symbols]

[0060] 10 Exposure equipment 12 Stages 20A, 20B, 20C Exposure head 21A, 21B, 21C DMD driver circuit 30 Encoder 32A, 32B Linear Scale 34A, 34B Scanning Head 50 Control section 60 Encoder signal correction processing circuit 64 Coordinate correction circuit

Claims

1. A plurality of exposure heads each having a light modulation element array and arranged along a sub-scanning direction; a scanning mechanism that moves a stage on which a substrate is placed along a main scanning direction and moves an exposure area of ​​each of the plurality of exposure heads relative to the substrate; an encoder for detecting a position of the stage during movement of the stage; an exposure control unit that drives and controls the light modulation element array of each exposure head based on drawing data corresponding to the position of the exposure area of ​​each exposure head from the detected position of the stage, and performs an exposure operation; The encoder is configured to detect a tilt of the stage; an exposure control unit that performs an exposure operation in accordance with a positional shift of an exposure area of ​​each exposure head caused by a tilt of the stage;

2. the exposure control unit includes a light modulation element array drive circuit that reads out drawing data sequentially stored in a memory in each exposure head based on an encoder signal from the encoder, and drives and controls the light modulation element array; 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 a tilt of the stage; 2. The exposure apparatus according to claim 1, wherein the light modulation element array drive circuit reads out drawing data stored in sequence in a memory in each exposure head based on a corrected encoder signal.

3. the encoder includes a pair of linear scales parallel to each other along a main scanning direction, and a pair of scanning heads attached to the stage for reading the graduations of the pair of linear scales; 3. The exposure apparatus according to claim 1, wherein an encoder signal for each exposure head is corrected from an encoder signal output from the pair of scanning heads.

4. The stage is movable along a sub-scanning direction, 4. An exposure apparatus according to claim 3, wherein the pair of linear scales are positioned outside the sub-scanning direction movement range of the stage during exposure operation so as to be able to detect the positions of both side surfaces of the stage during exposure operation.

5. 3. The exposure apparatus according to claim 1, wherein 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. 6. An exposure apparatus according to claim 5, wherein the encoder comprises a linear scale that is arranged along the main scanning direction in alignment with an intermediate position of the stage in the sub-scanning direction.

7. a stage on which a substrate is placed is moved along a main scanning direction relative to a plurality of exposure heads, each of which includes an array of light modulation elements and is arranged along a sub-scanning direction, thereby moving an exposure area of ​​each of the plurality of exposure heads relative to the substrate; An exposure method for performing an exposure operation by controlling the driving of a light modulation element array of each exposure head based on drawing data corresponding to a position of an exposure area of ​​each exposure head, comprising: Detecting the position of the stage, including the inclination of the stage, by an encoder while the stage is moving during an exposure operation; an encoder signal output from the encoder is corrected so that exposure operation is performed in accordance with a positional deviation of an exposure area of ​​each exposure head caused by a tilt of the stage;

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