Direct-writing exposure system

Abstract

To provide a direct-writing exposure system that can achieve high-precision exposure while preventing a decrease in throughput. [Solution] A direct-draw exposure apparatus according to one embodiment of the present invention comprises an exposure head, a stage, a scale, a first encoder, a second encoder, an exposure control unit, and a movement control unit. The exposure head irradiates an exposure pattern onto an exposure surface. The stage is movable relative to the exposure head and on which the object to be exposed is placed. The scale is fixed relative to the exposure head and extends along the direction of movement of the stage. The first encoder is fixed relative to the stage, detects the scale markings, and outputs a first output signal. The second encoder is fixed relative to the stage, detects the scale markings, and outputs a second output signal. The exposure control unit controls the exposure by the exposure head based on the first output signal. The movement control unit controls the movement of the stage based on the second output signal.

Description

[Technical Field]

[0001] The present invention relates to a direct-drawing exposure apparatus that performs exposure according to an exposure pattern formed by a spatial light modulator. [Background Art]

[0002] A direct-drawing exposure apparatus that performs exposure by irradiating an exposure object such as a substrate with an exposure pattern formed by an exposure head provided with a spatial light modulator is known. In a direct-drawing exposure apparatus, the exposure object is placed on a stage, and moves relative to the exposure head as the stage moves. The exposure head irradiates an exposure pattern in accordance with the movement of the stage, thereby enabling exposure over a wide range of the exposure object.

[0003] In a direct-drawing exposure apparatus, a linear encoder is used for position control of the stage (see, for example, Patent Documents 1 to 3). The linear encoder reads the scale of a linear scale while moving together with the stage to detect the position of the stage. The exposure head is controlled based on the position of the stage detected by the linear encoder, and performs exposure. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-283896 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-030873 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-271867 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] In conventional direct-writing exposure systems, a frequency division function of the motor driver that controls the motor for moving the stage was used to improve the positional resolution of the stage. However, using the frequency division function limits the stage's movement speed due to the limitations of the motor driver. In particular, in recent years, high precision in exposure has been required, and increasing the frequency division ratio to improve positional resolution leads to a significant decrease in the stage's movement speed, resulting in a problem of reduced throughput in the direct-writing exposure system.

[0006] In view of the above circumstances, the object of the present invention is to provide a direct-writing exposure apparatus that can prevent a decrease in throughput while achieving high precision in exposure. [Means for solving the problem]

[0007] To achieve the above objective, a direct-drawing exposure apparatus according to one embodiment of the present invention is a direct-drawing exposure apparatus that irradiates an exposure pattern formed by a spatial light modulator onto the exposure surface of an object to be exposed, and comprises an exposure head, a stage, a scale, a first encoder, a second encoder, an exposure control unit, and a movement control unit. The exposure head is provided with the spatial light modulator and irradiates the exposure pattern onto the exposure surface. The stage is movable relative to the exposure head along a predetermined direction, and the object to be exposed is placed on it. The scale is fixed to the exposure head and extends along the direction of movement of the stage. The first encoder is fixed to the stage, detects the scale markings, and outputs a first output signal. The second encoder is fixed to the stage, detects the scale markings, and outputs a second output signal. The exposure control unit controls the exposure by the exposure head based on the first output signal. The movement control unit controls the movement of the stage based on the second output signal.

[0008] In this configuration, the exposure control unit controls exposure based on the first output signal output by the first encoder, and the movement control unit controls the movement of the stage based on the second output signal output by the second encoder. Since exposure control and stage movement control are performed based on the outputs of separate encoders, it is not necessary to use the frequency division function of the motor driver to improve the position resolution of the stage, making it possible to achieve high-precision exposure while preventing a decrease in throughput.

[0009] The exposure control unit may identify the position of the stage in the predetermined direction based on the first output signal and generate stage position information indicating the position of the stage.

[0010] The direct-draw exposure apparatus further comprises an exposure head control unit that controls the exposure head, The exposure control unit supplies the stage position information to the exposure head control unit. The exposure head control unit may control the exposure head based on the stage position information.

[0011] The exposure head control unit may control the spatial light modulator according to the stage position information so that a predetermined exposure pattern is irradiated onto the region of the exposure surface that is exposed by the exposure head.

[0012] The exposure head has an autofocus module for adjusting the focus of the exposure head. The direct-writing exposure apparatus further comprises an autofocus control unit that controls the autofocus module, The exposure control unit supplies the stage position information to the autofocus control unit. The autofocus control unit may control the autofocus module based on the stage position information.

[0013] Said autofocus control unit stores a separation distance, which is the distance between said exposure head and said exposure surface, in association with said stage position information, specifies said separation distance in accordance with said stage position information, and may control said autofocus module so as to focus on said exposure surface in accordance with said separation distance.

[0014] Said direct-drawing exposure apparatus further comprises an alignment camera that photographs said exposure object, and an alignment camera control unit that controls said alignment camera, Said exposure control unit supplies said stage position information to said alignment camera control unit, Said alignment camera control unit may control said alignment camera based on said stage position information.

[0015] Said alignment camera control unit associates a captured image with said stage position information and supplies the same to said exposure control unit, Said exposure control unit may specify the positional relationship between said stage and said exposure object based on said captured image and said stage position information, and correct the exposure pattern supplied to said exposure head control unit based on said positional relationship.

[0016] Said movement control unit may control the movement amount and movement speed of said stage in said predetermined direction in accordance with said second output signal.

[0017] Said direct-drawing exposure apparatus further comprises a motor that moves said stage along said predetermined direction, and a motor driver that drives said motor, Said motor driver may supply the second output signal output from said second encoder to said movement control unit without frequency division. Effects of the Invention

[0018] According to the present invention, it is possible to provide a direct-drawing exposure apparatus capable of preventing a decrease in throughput while achieving high-precision exposure. Brief Description of the Drawings

[0019] [Figure 1] It is a schematic diagram of a direct-drawing exposure apparatus according to an embodiment of the present invention. [Figure 2] It is a schematic diagram of an exposure head included in the above-mentioned direct-drawing exposure apparatus. [Figure 3] It is a schematic diagram of exposure performed by the above-mentioned direct-drawing exposure apparatus. [Figure 4] It is a block diagram showing a configuration related to stage movement of the above-mentioned direct-drawing exposure apparatus. [Figure 5] It is a block diagram showing signal processing related to stage movement of the above-mentioned direct-drawing exposure apparatus. [Figure 6] It is a block diagram showing signal processing related to stage movement in a conventional method. [Figure 7] It is a schematic diagram showing a home position return operation in the above-mentioned direct-drawing exposure apparatus. [Figure 8] It is a schematic diagram showing a home position return operation in the above-mentioned direct-drawing exposure apparatus. [Figure 9] It is a schematic diagram showing a home position return operation in the above-mentioned direct-drawing exposure apparatus. [Figure 10] It is a schematic diagram showing a home position return operation in the above-mentioned direct-drawing exposure apparatus. MODE FOR CARRYING OUT THE INVENTION

[0020] A direct-drawing exposure apparatus according to an embodiment of the present invention will be described.

[0021] [Configuration of Direct-Drawing Exposure Apparatus] FIG. 1 is a schematic diagram showing a configuration of a direct-drawing exposure apparatus 1 according to the present embodiment. As shown in this figure, the direct-drawing exposure apparatus 1 includes a direct-drawing exposure machine 10, a light source unit 11, and a control device 12.

[0022] The direct-drawing exposure apparatus 1 uses a direct-drawing exposure machine 10 and a light source unit 11 to expose an object 14 based on raster data obtained by rasterizing a predetermined drawing pattern (e.g., a printed circuit pattern), thereby irradiating the object 14 with a desired exposure pattern without the need for a mask.

[0023] The object to be exposed 14 is, for example, a printed circuit board or a glass substrate for a flat panel display on which a photosensitive material is coated or attached to the exposure surface 14a. The specific type of object to be exposed 14 is not limited. Alignment marks 15 are provided on the exposure surface 14a to indicate the reference exposure position. The alignment marks 15 are formed, for example, by the unevenness of a thin film, and are arranged one at each of the four corners of the exposure surface 14a, for a total of four marks.

[0024] The direct-draw exposure machine 10 has a flat base 16. The base 16 is supported by four legs 17 and is arranged parallel to the horizontal plane (the XY plane shown in Figure 1). The short side of the base 16 coincides with the X direction, and the long side coincides with the Y direction.

[0025] Two guide rails 18 are provided side by side on the upper surface of the base 16, parallel to each other in the Y direction. A stage 19, which holds the object to be exposed 14 by suction, is attached to the guide rails 18 so as to be slidable in the Y direction. When the object to be exposed 14 is placed on the stage 19, the exposure surface 14a becomes parallel to the XY plane.

[0026] Stage 19 is configured to reciprocate in the Y direction by a motor, which will be described later. As a result, the object to be exposed 14 placed on stage 19 is also transported in the Y direction. Although not shown in the illustration, stage 19 is also equipped with a movement mechanism for adjusting its position in the Z direction.

[0027] In this embodiment, the stage 19 does not move in the X direction or the rotational direction (θ direction in Figure 1). This reduces the number of movement axes and makes it possible to reduce errors related to movement. On the other hand, movement in the X direction or rotational direction may be possible.

[0028] An exposure unit 20 is positioned in the center of the base 16 in the Y direction. The exposure unit 20 is fixed to a gate-shaped first gate 21 that is erected to straddle the guide rail 18. The exposure unit 20 is equipped with a total of eight cylindrical exposure heads 22, four in each direction along the X direction and arranged in two rows along the Y direction.

[0029] Figure 2 is a schematic diagram showing the configuration of the exposure head 22. As shown in the figure, the exposure head 22 includes an incident optical system 51, a spatial light modulator 52, an illumination optical system 53, and an AF (autofocus) module 54.

[0030] The incident optical system 51 is connected to the light source unit 11 by an optical fiber 61 and includes a collimating lens 62 and a mirror 63. In the light source unit 11, light L emitted from the light source is transmitted to the incident optical system 51 via the optical fiber 61 and then to the spatial light modulator 52 via the collimating lens 62 and mirror 63. Light L is, for example, laser light.

[0031] The spatial light modulator 52 modulates the light L incident from the incident optical system 51. The spatial light modulator 52 is connected to the control device 12 and performs modulation according to the control signal supplied by the control device 12. As the spatial light modulator 52, a DMD (Digital Micromirror Device) can be used, in which a large number (e.g., 1024 x 768) of small mirrors are arranged in a planar shape. The DMD allows control of the angle of each micromirror, and each micromirror can be switched between a state in which the incident light is reflected toward the illumination optical system 53 (hereinafter referred to as the "on state") and a state in which the incident light L is reflected toward a direction different from the illumination optical system 53 (hereinafter referred to as the "off state").

[0032] The illumination optical system 53 irradiates the object to be exposed 14 with light L incident from the spatial light modulator 52. The illumination optical system 53 has a lens 64 and a microlens array 65, and directs the light L incident from the spatial light modulator 52 onto the exposure surface 14a via the AF module 54.

[0033] The AF module 54 adjusts the focus of the exposure head 22. The AF module 54 is positioned between the illumination optical system 53 and the object to be exposed 14, and adjusts the focus of the exposure head 22 so that the focal point of the light L incident from the illumination optical system 53 coincides with the exposure surface 14a. The AF module 54 is connected to the control device 12 and performs focus adjustment according to the control signal supplied from the control device 12. The AF module 54 can be a prism pair or the like.

[0034] The exposure head 22 has the configuration described above. Although the configuration of one exposure head 22 has been described here, the other exposure heads 22 have a similar configuration. Note that the configuration of the exposure head 22 is not limited to that shown here; it is sufficient if it is capable of irradiating the exposure surface 14a with light modulated by the spatial light modulator 52. The number of exposure heads 22 in the direct-writing exposure machine 10 is not limited to eight; one or more are sufficient.

[0035] The AF (autofocus) sensor 27 (see Figure 1) is provided in conjunction with each exposure head 22 and measures the distance between each exposure head 22 and the exposure surface 14a. The AF sensor 27 is connected to the control device 12 and supplies the measured distance to the control device 12. As the AF sensor 27, a laser interferometer type displacement meter can be used, which measures the distance between the exposure head 22 and the exposure surface 14a by irradiating the exposure surface 14a with laser light and receiving the reflected light at the right time.

[0036] A gate-shaped second gate 25 is erected on the base 16, straddling the guide rail 18. Three alignment cameras 28 are installed on the second gate 25 to photograph the exposure target object 14, which passes directly beneath it as the stage 19 moves in the Y direction, from above in the Z direction. The alignment cameras 28 are connected to the control device 12 and supply the captured images to the control device 12. The number of alignment cameras 28 equipped in the direct-drawing exposure machine 10 is not limited to three; one or more are sufficient.

[0037] The direct-drawing exposure machine 10 has the configuration described above. However, the configuration of the direct-drawing exposure machine 10 is not limited to that shown here; it is sufficient if the exposure pattern can be irradiated onto the exposure surface 14a of the object to be exposed 14 by moving the stage 19.

[0038] The light source unit 11 is connected to the incident optical system 51 (see Figure 2) of each exposure head 22 by an optical fiber 61, and supplies light L to each incident optical system 51. The light source unit 11 includes a light source and an optical system that causes the light emitted from the light source to enter each optical fiber 61. The light source is, for example, a laser light source.

[0039] The control device 12 controls the direct-writing exposure machine 10 to perform exposure. The control device 12 has a functional configuration realized through the cooperation of software and hardware, the details of which will be described later. The software may be stored on a storage medium provided by the control device 12, or it may be obtained from a recording medium or information communication network that can be read by the information processing device. The hardware includes an arithmetic unit such as a CPU (Central Processing Unit) and main memory, and is configured to enable information processing.

[0040] The control device 12 may be an information processing device incorporated into the direct-writing exposure machine 10, or it may be an information processing device connected to the direct-writing exposure machine 10 directly or via an information and communication network. Furthermore, part of the functional configuration of the control device 12 may be incorporated into the direct-writing exposure machine 10, or part or all of the functional configuration may be realized via an information and communication network.

[0041] [About exposure using a direct-drawing exposure system] Figure 3 is a schematic diagram showing exposure by a direct-drawing exposure machine 10. As indicated by arrow A in the figure, the direct-drawing exposure machine 10 performs exposure while moving the object to be exposed 14 in the Y direction by the stage 19. The figure shows the irradiation spots S of light irradiated onto the exposure surface 14a from each exposure head 22. As shown in an enlarged view in Figure 3, the irradiation spot S contains a large number of minute patterns M, and each minute pattern M is formed by a spatial light modulator 52. Specifically, light is incident on the minute patterns M corresponding to the ON state micromirrors, and light is not incident on the minute patterns M corresponding to the OFF state micromirrors. The spatial light modulator 52 is controlled by the control device 12 in accordance with the movement of the stage 19, switching the presence or absence of light incidence on each minute pattern M.

[0042] As the stage 19 moves in the Y direction, the area of ​​the exposure surface 14a that has passed through the irradiation spot S is exposed. In Figure 3, the area of ​​the exposure surface 14a that has passed through the irradiation spot S of each exposure head 22 is shown as the exposure area E. The exposure heads 22 are arranged so that their ends overlap between adjacent exposure areas E, and are configured to expose the exposure surface 14a without any gaps.

[0043] [Configuration related to stage transitions] The configuration related to stage movement of the direct-drawing exposure apparatus 1 will now be described. Figure 4 is a block diagram showing the configuration related to stage movement of the direct-drawing exposure apparatus 1. As shown in the figure, the direct-drawing exposure apparatus 1 includes a stage 19, a scale 121, a moving motor 122, a first encoder 123, a second encoder 124, a serial converter 125, a motor driver 126, a movement control unit 127, an exposure control unit 128, a head control unit 129, an AF (autofocus) control unit 130, and an alignment camera control unit 131. Of these, the movement control unit 127, the exposure control unit 128, the head control unit 129, the AF control unit 130, and the alignment camera control unit 131 are functional components of the control device 12.

[0044] As described above, the stage 19 is movable relative to the base 16 along the Y direction, that is, movable relative to the exposure head 22 along the Y direction. The object to be exposed 14 is placed on the stage 19. The scale 121 is a linear scale and is fixed to the base 16 and also to the exposure head 22. The scale 121 extends along the Y direction, which is the direction of movement of the stage 19. The type of scale 121 is not particularly limited and may be any type of scale, such as a transmissive photoelectric scale, a reflective photoelectric scale, or an electromagnetic induction scale.

[0045] The moving motor 122 moves the stage 19 along the Y direction relative to the base 16, that is, moves the stage 19 along the Y direction relative to the exposure head 22. The moving motor 122 is supplied with a drive signal, which will be described later, from the motor driver 126 and operates according to that drive signal. A linear motor with a stator that extends along the Y direction can be used as the moving motor 122.

[0046] The first encoder 123 is fixed to the stage 19 and connected to the exposure control unit 128. The first encoder 123 detects the scale 121 and outputs a signal to the exposure control unit 128 according to the detected scale. Hereinafter, the signal output by this first encoder 123 will be referred to as the "first output signal". The first output signal is not particularly limited, but can be a TTL (Transistor Transistor Logic) signal, for example.

[0047] The second encoder 124 is fixed to the stage 19 and connected to the serial converter 125. The second encoder 124 detects the scale markings on the scale 121 and outputs a signal to the serial converter 125 according to the detected markings. That is, the first encoder 123 and the second encoder 124 detect the same scale markings. Hereinafter, the signal output by this second encoder 124 will be referred to as the "second output signal". The second output signal is not particularly limited, but can be an analog signal, for example. The second output signal may also be the same type of signal as the first output signal.

[0048] The serial converter 125 is connected to the second encoder 124 and the motor driver 126, and the second output signal is supplied from the second encoder 124. The serial converter 125 performs serial conversion on the second output signal and supplies the serially converted second output signal to the motor driver 126.

[0049] The motor driver 126 is connected to the mobile motor 122, the serial converter 125, and the movement control unit 127, and drives the mobile motor 122. When the serial-converted second output signal is supplied from the serial converter 125, the motor driver 126 supplies that signal to the movement control unit 127. Also, when the motor driver 126 receives a control signal from the movement control unit 127 to control the movement of the stage 19, it generates a drive signal to drive the mobile motor 122 according to that control signal and supplies it to the mobile motor 122.

[0050] The movement control unit 127 controls the movement of the stage 19 based on the second output signal. The movement control unit 127 can control the movement of the stage 19 by sequentially determining the position of the stage 19 based on the second output signal and controlling the amount of movement and the speed of movement in the Y direction accordingly. Specifically, the movement control unit 127 generates a control signal that specifies the amount of movement and the speed of movement of the stage 19 and supplies it to the motor driver 126.

[0051] The exposure control unit 128 controls exposure by the exposure head 22 based on the first output signal. Based on the first output signal, the exposure control unit 128 sequentially determines the position of the stage 19 in the Y direction and sequentially generates "stage position information" indicating the position of the stage 19. The stage position information is the distance from a predetermined reference position, for example, information such as "+1000mm". The exposure control unit 128 controls exposure by the exposure head 22 by supplying the generated stage position information to the head control unit 129, the AF control unit 130, and the alignment camera control unit 131.

[0052] Specifically, the exposure control unit 128 holds an exposure pattern to be drawn on the object to be exposed 14 (hereinafter referred to as the "overall exposure pattern"). The exposure control unit 128 generates exposure patterns (hereinafter referred to as "divided exposure patterns") by dividing this overall exposure pattern into exposure regions E (see Figure 3). The exposure control unit 128 supplies each divided exposure pattern to the head control unit 129 of the exposure head 22 responsible for that exposure region E. Furthermore, when the movement of the stage 19 begins, the exposure control unit 128 generates stage position information based on the first output signal and supplies it to the head control unit 129 of each exposure head 22.

[0053] Each head control unit 129 is provided, corresponding to each exposure head 22. If the direct-writing exposure machine 10 has eight exposure heads 22, the control device 12 has eight head control units 129. Each head control unit 129 controls the exposure head 22 it is responsible for based on stage position information supplied from the exposure control unit 128.

[0054] Specifically, the head control unit 129 switches the angle of each micromirror of the spatial light modulator 52 between an on state and an off state based on the segmented exposure pattern and stage position information supplied from the exposure control unit 128, thereby switching the presence or absence of light incidence on the minute pattern M (see Figure 3), and controls the spatial light modulator 52 so that a segmented exposure pattern is formed in the exposure area E of each exposure head 22.

[0055] One AF (autofocus) control unit 130 is provided for each exposure head 22, and if the direct-drawing exposure machine 10 has eight exposure heads 22, the control device 12 has eight AF control units 130. The AF control unit 130 controls the AF module 54 (see Figure 2) based on stage position information supplied from the exposure control unit 128. The AF control unit 130 maintains the distance between the exposure head 22 and the exposure surface 14a (hereinafter referred to as the separation distance) in association with the stage position information as follows.

[0056] The AF control unit 130 measures the separation distance before exposure begins. Specifically, the AF sensor 27 (see Figure 1) sequentially measures the separation distance while the stage 19 is moving. At this time, the AF control unit 130 is supplied with stage position information sequentially from the exposure control unit 128 and records the stage position information in association with the separation distance. Each AF control unit 130 measures the separation distance for each exposure head 22 as described above, and individually associates the stage position information with the separation distance to generate a separation distance distribution for each stage position (hereinafter referred to as the "separation distance distribution").

[0057] When exposure begins, the AF control unit 130 sequentially determines the separation distance at each stage position using stage position information and separation distance distribution, and sequentially controls the AF module 54 so that the exposure head 22 is in focus on the exposure surface 14a according to the separation distance. Each AF control unit 130 performs the above autofocus control individually for each exposure head 22.

[0058] The alignment camera control unit 131 controls the alignment camera 28 (see Figure 1) based on the stage position information supplied from the exposure control unit 128. The alignment camera control unit 131 takes a photograph of the object to be exposed 14 before exposure begins. Specifically, it photographs the object to be exposed 14 on the stage 19 while the stage 19 is moving, associates the stage position information at the time of shooting with the captured image, and supplies it to the exposure control unit 128.

[0059] The exposure control unit 128 detects the object to be exposed 14 on the stage 19 based on the captured image supplied by the alignment camera control unit 131 and identifies the positional relationship between the stage 19 and the object to be exposed 14. The exposure control unit 128 can detect the object to be exposed 14 in the captured image by extracting the periphery of the object to be exposed 14 and alignment marks 15 provided on the object to be exposed 14 through image processing of the captured image. The exposure control unit 128 can correct the segmented exposure pattern according to the identified positional relationship between the stage 19 and the object to be exposed 14, for example, the position of the object to be exposed 14 (X direction and Y direction in Figure 1) and angle (θ direction in Figure 1).

[0060] [Operation of a direct-writing exposure system] The operation of the direct-writing exposure apparatus 1 will now be explained. In the direct-writing exposure apparatus 1, after the object to be exposed 14 is placed on the stage 19, the "measurement operation" and the "exposure operation" are performed.

[0061] During the measurement operation, the stage 19 begins to move from the initial position shown in Figure 1. The movement control unit 127 controls the movement motor 122 based on the second output signal output by the second encoder 124 (see Figure 4), moving the stage 19 along the Y direction towards the upper right in Figure 1. Simultaneously, the exposure control unit 128 sequentially determines the position of the stage 19 based on the first output signal output by the first encoder 123 and generates stage position information. The exposure control unit 128 sequentially supplies the stage position information to the AF control unit 130 and the alignment camera control unit 131.

[0062] As the stage 19 passes below the exposure unit 20, the AF sensors 27 corresponding to each exposure head 22 sequentially measure the distance between each exposure head 22 and the exposure surface 14a, and generate a distance distribution in association with the stage position information. Furthermore, when the stage 19 reaches the shooting range of the alignment camera 28, the alignment camera control unit 131 causes the alignment camera 28 to photograph the object to be exposed 14, and supplies the captured image and the stage position information in association to the exposure control unit 128.

[0063] The exposure control unit 128 identifies the positional relationship between the stage 19 and the object to be exposed 14 based on the captured image, and corrects the segmented exposure pattern according to the identified positional relationship. The exposure control unit 128 supplies the corrected segmented exposure pattern to the head control unit 129 of each exposure head 22.

[0064] During the exposure operation, the stage 19 begins to move from the position where the measurement operation has finished, i.e., the upper right in Figure 1. The movement control unit 127 controls the movement motor 122 based on the second output signal output by the second encoder 124, moving the stage 19 along the Y direction towards the lower left in Figure 1. Simultaneously, the exposure control unit 128 sequentially determines the position of the stage 19 based on the first output signal output by the first encoder 123 and generates stage position information. The exposure control unit 128 supplies the stage position information to the head control unit 129 and the AF control unit 130.

[0065] As the stage 19 passes below the exposure unit 20, the AF control unit 130 sequentially determines the separation distance of each exposure head 22 using the stage position information and the separation distance distribution. This separation distance varies depending on the position of the stage 19, but it can be determined using the stage position information and the separation distance distribution. The AF control unit 130 sequentially controls the AF module 54 so that the focus of each exposure head 22 is aligned with the exposure surface 14a according to the separation distance.

[0066] Simultaneously, the head control unit 129 sequentially controls the spatial light modulator 52 based on the stage position information so that a segmented exposure pattern is formed in the exposure area E (see Figure 3) of each exposure head 22. The head control unit 129 uses the stage position information to control the control timing of the spatial light modulator 52, specifically the on / off timing of each micromirror, thereby switching the presence or absence of light incidence on each minute pattern M and forming a segmented exposure pattern in the exposure area E.

[0067] When stage 19 returns to its initial position, exposure is complete and the object to be exposed 14 is removed. When a new object to be exposed 14 is placed on stage 19, the above measurement and exposure operations are performed, and exposure takes place.

[0068] [Regarding signal processing related to stage transitions] The signal processing related to stage movement in the direct-draw exposure apparatus 1 will be explained. Figure 5 is a schematic diagram showing this signal processing, with the upper part of the figure showing the signal processing related to the movement control of stage 19, and the lower part showing the signal processing related to exposure control.

[0069] For the movement control of stage 19, as shown in the upper part of the figure, the second encoder 124 outputs a second output signal. The second encoder 124 can detect the scale markings on the scale 121 (see Figure 2) and output a second output signal according to the detected markings. The second output signal output from the second encoder 124 is supplied to the serial converter 125, where it is converted to serial format before being supplied to the motor driver 126.

[0070] The motor driver 126 supplies a second output signal to the movement control unit 127, which sequentially determines the position of the stage 19 based on the second output signal. The accuracy of this position is sufficient for controlling the movement of the stage 19, but insufficient for exposure control, which will be described later. The movement control unit 127 generates a control signal that specifies the amount of movement and the speed of movement according to the position of the stage 19 and supplies it to the motor driver 126. The motor driver 126 generates a drive signal to drive the movement motor 122 according to this control signal and supplies it to the movement motor 122. As a result, the movement motor 122 is driven and the stage 19 moves.

[0071] For exposure control, as shown in the lower part of the figure, the first encoder 123 outputs a first output signal. The first encoder 123 can detect the scale 121 (see Figure 2) and output a first output signal according to the detected scale. The first output signal output from the first encoder 123 is supplied to the exposure control unit 128, which sequentially determines the position of the stage 19 based on the first output signal and generates stage position information.

[0072] The exposure control unit 128 supplies the generated stage position information to the head control unit 129, the AF control unit 130, and the alignment camera control unit 131. Based on this, the head control unit 129, the AF control unit 130, and the alignment camera control unit 131 control their respective parts as described above and perform exposure.

[0073] On the other hand, Figure 6 is a schematic diagram showing the signal processing related to stage movement control of a conventional direct-draw exposure apparatus 300 for comparison. When the encoder 301 provided on the stage detects a mark on the linear scale, an output signal is output from the encoder 301, as shown in Figure 6. This output signal is serial-converted by the serial converter 302 and then supplied to the motor driver 303. The motor driver 303 divides the frequency of the output signal, and the divided output signal is supplied to the exposure control unit 304.

[0074] In the exposure control unit 304, the stage position is sequentially determined based on the divided output signal. Because the output signal is divided, the resolution of the stage position is improved, and the accuracy of the stage position becomes sufficient for exposure. The exposure control unit 304 supplies the generated stage position information to the head control unit 305, the AF (autofocus) control unit 306, and the alignment camera control unit 307, which then control their respective components to perform exposure.

[0075] In direct-draw exposure systems, it is necessary to precisely control the irradiation position and focus of the exposure pattern relative to the object being exposed. Therefore, conventionally, as described above (see Figure 6), the motor driver 303 performed frequency division of the encoder output signal to improve the resolution of the stage position. While this process limits the operating speed of the encoder 301 due to serial conversion and frequency division, it was still a sufficient speed and not considered a problem.

[0076] On the other hand, in recent years, the resolution of exposure patterns has increased, and there is a demand for further improvement in the resolution of the stage position. In response to this, it is possible to further improve the resolution of the stage position by increasing the frequency division ratio. However, in this case, the operating speed of the encoder 301 becomes insufficient, resulting in a problem of reduced throughput.

[0077] For example, if the encoder's maximum operating speed is 4000 mm / s, the speed limitation due to frequency division with conventional frequency division is 720 mm / s. This is above the 500 mm / s speed required to avoid throughput degradation and is therefore sufficient. However, if the frequency division is set to the level required for high-resolution exposure patterns, the speed limitation due to frequency division becomes 144 mm / s, which is below 500 mm / s and therefore insufficient.

[0078] In contrast, in the direct-drawing exposure apparatus 1 according to this embodiment, as described above (see Figure 5), the exposure control unit 128 determines the position of the stage 19 based on the first output signal output by the first encoder 123 provided on the stage 19. Furthermore, the movement control unit 127 controls the movement of the stage 19 based on the second output signal output by the second encoder 124 provided on the stage 19. Therefore, in the direct-drawing exposure apparatus 1, the movement control of the stage 19 and the exposure control according to the position of the stage 19 are performed based on the output signals of separate encoders.

[0079] Therefore, there is no need to utilize the frequency division function of the motor driver 126, and the operating speed of the second encoder 124 is not limited, thus preventing the problem of reduced throughput. Furthermore, since the first encoder 123 is used only for detecting the position of the stage 19, it is possible to output signals suitable for high resolution, such as TTL signals. Thus, the direct-writing exposure apparatus 1 can achieve both improved position resolution of the stage 19 and high throughput.

[0080] Furthermore, the first encoder 123 and the second encoder 124 measure the position of the stage 19 by detecting the same scale markings on the same scale 121. This eliminates the need for the direct-writing exposure machine 10 to have multiple scales 121, enabling space savings and cost reductions. If multiple scales 121 were to be provided, the scale pitch of the linear scales would be on the order of submicrons, leading to errors in the detection position of the stage 19 due to errors between the linear scales. However, this problem does not occur in the direct-writing exposure machine 10.

[0081] [Regarding returning to the origin] In the direct-drawing exposure apparatus 1, the following home position return operation is performed, enabling the movement control unit 127 (see Figure 4) to move the stage 19 based on the position of the stage 19 identified based on the first output signal. The first output signal is the output signal output by the first encoder 123 as described above, and is the output signal used by the exposure control unit 128 for exposure control. This home position return operation is performed when the direct-drawing exposure apparatus 1 is installed, etc.

[0082] Figures 7 to 10 are schematic diagrams showing the origin return operation in the direct-draw exposure apparatus 1. In these figures, the "Z phase" is a marker provided on the scale 121, which can be detected by the first encoder 123 and the second encoder 124. For example, the Z phase is a slit provided on the scale 121, and the encoder can detect the Z phase by detecting that the light it emits has passed through the slit.

[0083] In scale 121, the initial position and the Z-phase position are precisely predetermined, and if the distance between the initial position and the Z-phase is denoted as "Y1", then "Y1" is an accurate value. On the other hand, if the distance between the first encoder 123 and the second encoder 124 is denoted as "Y2", then Y2 may be inaccurate due to variations inherent in the encoders and errors due to the scale position. For example, the design value of Y2 may be 300 mm, but in reality it may be 305 mm.

[0084] During the return to home position operation, the movement control unit 127 (see Figure 4) controls the movement motor 122 to move the stage 19. As shown in Figure 7, when the second encoder 124 detects the Z phase, the movement control unit 127 sets the position coordinates of the second encoder 124 to "Y1". The movement control unit 127 moves the stage 19 further, and as shown in Figure 8, when the first encoder 123 detects the Z phase, the exposure control unit 128 sets the position coordinates of the first encoder 123 to "Y1+Y2".

[0085] Next, as shown in Figure 9, the movement control unit 127 moves the stage 19 to its initial position. At this time, the movement control unit 127 controls the movement motor 122 so that the amount of movement of the stage 19 is "Y1 + Y2". As a result, the position coordinates of the second encoder 124 detected by the movement control unit 127 become "0", but the position coordinates of the first encoder 123 detected by the exposure control unit 128 become "0 + α". This α includes the errors due to the encoder's inherent variations and scale position, as described above.

[0086] Next, the movement control unit 127 obtains the value of "α" from the exposure control unit 128 and sets the position coordinates of the second encoder 124 to "α". This allows the movement control unit 127 to move the stage 19 based on the position of the stage 19 identified based on the first output signal.

[0087] [About this disclosure] It is also possible to combine at least two of the feature elements of this technology described above. Furthermore, the various effects described above are merely examples and are not limiting, and other effects may also occur. [Explanation of Symbols]

[0088] 1…Direct-writing exposure system 10…Direct-drawing exposure machine 14…Object to be exposed 19… Stage 22… Exposure head 52...Spatial light modulator 121... Scale 122...Movement motor 123...First Encoder 124...Second encoder 126...Motor Driver 127...Movement Control Unit 128... Exposure Control Unit 129...Head Control Unit 130... Autofocus control unit 131... Alignment Camera Control Unit

Claims

1. A direct-writing exposure apparatus that irradiates the exposure surface of an object to be exposed with an exposure pattern formed by a spatial light modulator, The spatial light modulator is provided, and an exposure head is provided for irradiating the exposure pattern onto the exposure surface, A stage on which the object to be exposed is placed, which is movable relative to the exposure head along a predetermined direction, A scale fixed to the exposure head and extending along the direction of movement of the stage, A first encoder is fixed to the stage, detects the scale markings, and outputs a first output signal. A second encoder is fixed to the aforementioned stage, detects the scale markings, and outputs a second output signal. An exposure control unit that controls exposure by the exposure head based on the first output signal, A movement control unit that controls the movement of the stage based on the second output signal, and A direct-writing exposure apparatus equipped with the following:

2. A direct-writing exposure apparatus according to claim 1, The exposure control unit identifies the position of the stage in the predetermined direction based on the first output signal and generates stage position information indicating the position of the stage. Direct-writing exposure system.

3. A direct-writing exposure apparatus according to claim 2, The direct-draw exposure apparatus further comprises an exposure head control unit that controls the exposure head, The exposure control unit supplies the stage position information to the exposure head control unit. The exposure head control unit controls the exposure head based on the stage position information. Direct-writing exposure system.

4. A direct-writing exposure apparatus according to claim 3, The exposure head control unit controls the spatial light modulator according to the stage position information so that a predetermined exposure pattern is irradiated onto the region of the exposure surface that is exposed by the exposure head. Direct-writing exposure system.

5. A direct-writing exposure apparatus according to claim 2, The exposure head has an autofocus module for adjusting the focus of the exposure head. The direct-writing exposure apparatus further comprises an autofocus control unit that controls the autofocus module, The exposure control unit supplies the stage position information to the autofocus control unit. The autofocus control unit controls the autofocus module based on the stage position information. Direct-writing exposure system.

6. A direct-writing exposure apparatus according to claim 5, The autofocus control unit maintains a separation distance, which is the distance between the exposure head and the exposure surface, in association with the stage position information. It identifies the separation distance according to the stage position information and controls the autofocus module to bring the exposure surface into focus according to the separation distance. Direct-writing exposure system.

7. A direct-writing exposure apparatus according to claim 2, The direct-draw exposure apparatus further comprises an alignment camera for photographing the object to be exposed and an alignment camera control unit for controlling the alignment camera. The exposure control unit supplies the stage position information to the alignment camera control unit. The alignment camera control unit controls the alignment camera based on the stage position information. Direct-writing exposure system.

8. A direct-draw exposure apparatus according to claim 7, The alignment camera control unit associates the captured image with the stage position information and supplies it to the exposure control unit. The exposure control unit identifies the positional relationship between the stage and the object to be exposed based on the captured image and the stage position information, and corrects the exposure pattern supplied to the exposure head control unit based on the positional relationship. Direct-writing exposure system.

9. A direct-writing exposure apparatus according to claim 1, The movement control unit controls the amount of movement and the speed of movement of the stage in the predetermined direction according to the second output signal. Direct-writing exposure system.

10. A direct-writing exposure apparatus according to claim 9, The direct-writing exposure apparatus further comprises a motor for moving the stage along the predetermined direction and a motor driver for driving the motor. The motor driver supplies the second output signal output from the second encoder to the motion control unit without frequency division. Direct-writing exposure system.

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