Direct imaging exposure device

Abstract

To provide a direct drawing type exposure apparatus that realizes autofocusing in projecting an exposure pattern onto a substrate.SOLUTION: An exposure pattern formed by a spatial light modulator 3 provided inside each exposure head 1A,1B is projected in an irradiation area by a projection optical system 4 in each exposure head 1A,1B, and a stage 6 mounting a substrate W is moved by a stage moving mechanism 61 to perform exposure such that the substrate W passes the irradiation area. An AF-use range finder 3 which measures a distance from the substrate W perform measurement, and a controller 7 controls an optical path length changer 91 or a mirror 82A provided between the exposure head 1A,1B and the irradiation area according to measurement data of the AF-use range finder 3 to achieve a focused state.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The invention of this application relates to a direct imaging exposure apparatus that forms an exposure pattern using a spatial light modulator and performs exposure. [Background technology]

[0002] Direct imaging exposure equipment is known as an exposure equipment used in photolithography processes, etc. Direct imaging exposure equipment is a type of maskless exposure equipment that forms an exposure pattern using a spatial light modulator such as a DMD (Digital Mirror Device) and directly draws and exposes the pattern without a mask. Direct imaging exposure equipment is extremely easy to change the exposure pattern as needed, making it suitable for small-lot production of a wide variety of products. For this reason, it is widely used for manufacturing circuit boards for various products and for manufacturing various micro-components (MEMS). The object to be exposed is often a plate (substrate), but it can also be non-plate-shaped. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-300543 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the invention of this application is to realize autofocus when projecting an exposure pattern onto a substrate in the above-mentioned direct imaging exposure apparatus. [Means for solving the problem]

[0005] In order to solve the above problems, the direct imaging exposure apparatus according to the invention disclosed in this specification is a direct imaging exposure apparatus that includes a stage on which a substrate is placed, a stage movement mechanism that moves the stage on which the substrate is placed from a standby position so that the substrate passes through an irradiation area, and an exposure head that houses a spatial light modulator that spatially modulates light from a light source and a projection optical system that projects the light pattern formed by the spatial light modulator onto the irradiation area, and that exposes the substrate with the light pattern formed by the spatial light modulator as the substrate passes through the irradiation area. The direct imaging exposure device includes a range finder that measures the distance to the substrate at a position between the stage moving from the standby position and the substrate reaching the irradiation area, and a light source on the optical path between the exposure head and the irradiation area. placed Optical path length changer and two mirrors and a controller that controls the optical path length changer in accordance with measurement data from the rangefinder to change the optical path length, thereby achieving a focused state with the projection optical system. The two mirrors are mirrors that bend the optical path whose optical path length is changed by the optical path length changer. Furthermore, in order to solve the above-mentioned problems, a direct imaging exposure apparatus according to another invention disclosed in this specification is a direct imaging exposure apparatus that includes: a stage on which a substrate is placed; a stage movement mechanism that moves the stage on which the substrate is placed from a standby position so that the substrate passes through an irradiation area; an exposure head that houses a spatial light modulator that spatially modulates light from a light source; and a projection optical system that projects the light pattern formed by the spatial light modulator onto the irradiation area, and that exposes the substrate with the light pattern formed by the spatial light modulator as the substrate passes through the irradiation area. The direct imaging exposure device includes a range finder that measures the distance to the substrate at positions between the stage being moved from the standby position and the substrate reaching the irradiation area, and an exposure head. From the projection optical system in Irradiation area until The system is provided with a mirror that bends the optical path, an actuator that moves the mirror to change the optical path length from the exposure head to the irradiation area, and a controller that controls the actuator in accordance with measurement data from a rangefinder to change the optical path length, thereby achieving a focused state with the projection optical system. [Effects of the Invention]

[0006] As will be explained below, the direct imaging exposure apparatus according to the disclosed inventions realizes autofocus when projecting an exposure pattern onto a substrate using a projection optical system. By providing an optical path length changer on the optical path between the exposure head and the irradiation area, the structure within the exposure head is simplified. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic front view of a direct imaging exposure apparatus according to a reference example. [Figure 2] FIG. 1 is a schematic side view of a direct imaging exposure apparatus according to a reference example. [Figure 3] FIG. 1 is a schematic plan view of a direct imaging exposure apparatus according to a reference example. [Figure 4] FIG. 2 is a schematic diagram showing the internal structure of the exposure head. [Figure 5] FIG. 10 is a schematic front view showing an offset optical system in a reference example. [Figure 6] FIG. 1 is a perspective schematic diagram showing one offset optical system. [Figure 7] FIG. 10 is a schematic plan view showing the action of each offset optical system. [Figure 8] 10A and 10B are schematic plan views showing the operation of a direct imaging exposure apparatus according to a reference example. [Figure 9] 10A and 10B are schematic diagrams showing the effect of improving productivity by each offset optical system. [Figure 10] 1 is a schematic front view showing a main part of a direct imaging exposure device according to a first embodiment. [Figure 11] FIG. 10 is a schematic front view showing the main part of a direct imaging exposure device according to a second embodiment. [Figure 12] FIG. 10 is a schematic front view showing the main parts of a direct imaging exposure device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, a mode (embodiment) for carrying out the invention of this application will be described. Prior to describing the direct imaging exposure apparatus of the embodiment, a direct imaging exposure apparatus of a reference example will be described. Figures 1 to 3 are schematic diagrams of the direct imaging exposure apparatus of the reference example, with Figure 1 being a schematic front view, Figure 2 being a schematic side view, and Figure 3 being a schematic plan view. The direct imaging exposure apparatus shown in FIGS. 1 to 3 includes a plurality of exposure heads 1A and 1B, a stage 6 on which a substrate W is placed, and a stage moving mechanism 61.

[0009] Each of the exposure heads 1A and 1B is cylindrical overall, arranged vertically, and emits light downward. Fig. 4 is a schematic diagram showing the internal structure of the exposure head. As shown in Fig. 4, each of the exposure heads 1A and 1B has a housing (not shown) that contains a light source 2, a spatial light modulator 3 that spatially modulates the light from the light source 2, and an optical system (hereinafter referred to as a projection optical system) 4 that projects an image formed by the light modulated by the spatial light modulator 3.

[0010] The light source 2 used is one that outputs light of an optimum wavelength depending on the photosensitive wavelength of the photosensitive layer on the substrate W. The photosensitive wavelength of resist films is often in the visible short wavelength range to the ultraviolet range, and so the light source 2 used is one that outputs light in the visible short wavelength range to the ultraviolet range, such as 405 nm or 365 nm. Furthermore, to make the most of the performance of the spatial light modulator 3, it is preferable that the light source output coherent light, and for this reason a laser light source is preferably used. For example, a gallium nitride (GaN) semiconductor laser is used.

[0011] In this reference example, a DMD is used as the spatial light modulator 3. As shown enlarged in Fig. 4, in the DMD, each pixel is a tiny mirror 31. The mirror (hereinafter referred to as pixel mirror) 31 is, for example, a square mirror with a side size of about 13.68 µm, and a large number of pixel mirrors 31 are arranged in a rectangular lattice pattern. The number of arrangements is, for example, 1024 x 768.

[0012] The spatial light modulator 3 includes a modulator controller 32 that controls each pixel mirror 31. The exposure apparatus of the reference example includes a main controller 7 that controls the entire system. The modulator controller 32 controls each pixel mirror 31 in accordance with signals from the main controller 7. Each pixel mirror 31 uses the plane on which the pixel mirrors 31 are arranged as a reference plane, and can take a first attitude along this reference plane and a second attitude inclined at, for example, approximately 11 to 13 degrees relative to this reference plane. The first attitude is the off state, and the second attitude is the on state. The spatial light modulator 3 includes a drive mechanism for driving each pixel mirror 31, and the modulator controller 32 can independently control whether each pixel mirror 31 takes the first position or the second position. Such a spatial light modulator 3 is available from Texas Instruments.

[0013] As shown in Fig. 4, the exposure heads 1A and 1B are equipped with an illumination optical system 5 that illuminates the spatial light modulator 3 with light from the light source 2. In this reference example, the illumination optical system 5 includes an optical fiber 51. In order to form an image with higher illuminance, each exposure head 1A and 1B is equipped with a plurality of light sources 2, and an optical fiber 51 is provided for each light source 2. As the optical fiber 51, for example, a quartz-based multimode fiber is used.

[0014] In order to form an image with high precision using the spatial light modulator 3, which is a DMD, it is desirable to make parallel light incident and have it reflected by each pixel mirror 31, and it is also desirable to make the light incident obliquely on each pixel mirror 31. For this reason, the irradiation optical system 5 includes a collimator lens 52, as shown in Fig. 4, which converts the diverging light emitted from each optical fiber 51 into parallel light.

[0015] The projection optical system 4 is composed of two projection lens groups 41 and 42 and a microlens array (hereinafter abbreviated as MLA) 43 arranged between the projection lens groups 41 and 42. The MLA 43 is arranged as an auxiliary element to perform exposure with higher shape accuracy. The MLA 43 is an optical component in which a large number of minute lens elements are arranged in a rectangular lattice pattern. Each lens element corresponds one-to-one to each pixel mirror 31 of the spatial light modulator 3.

[0016] In the above-described exposure heads 1A and 1B, light from the light source 2 is guided by the optical fiber 61 and then incident on the spatial light modulator 3 by the irradiation optical system 5. At this time, each pixel mirror 31 of the spatial light modulator 3 is controlled by the modulator controller 32 and selectively tilted in accordance with the exposure pattern. That is, in accordance with the exposure pattern to be formed, pixel mirrors 31 positioned to allow light to reach the irradiation area are turned on, and other pixel mirrors 31 are turned off. Light reflected by pixel mirrors 31 in the off state does not reach the irradiation area, and only light reflected by pixel mirrors 31 in the on state reaches the irradiation area. As a result, light of a predetermined exposure pattern is irradiated onto the irradiation area.

[0017] The stage 6 is a member on whose horizontal upper surface the substrate W is placed. The upper surface is provided with vacuum suction holes (not shown) that vacuum-suck the substrate W. The stage movement mechanism 61 is a mechanism that moves the stage 6 on which the substrate W is placed through the irradiation area. In this reference example, the stage movement mechanism 61 is a mechanism that not only moves the stage 6 in the X direction to pass through the irradiation area for exposure, but also moves the stage in the X direction. Specifically, the stage movement mechanism 61 includes an X-direction linear guide 611 arranged along the X direction through the irradiation areas EA and EB, a base 612 provided on the X-direction linear guide 611, an X-direction drive source (not shown) that moves the base 612 along the X-direction linear guide 611, and a Y-direction linear guide 613 provided on the base 612. The stage 6 is mounted on the Y-direction linear guide 613, and is provided with a Y-direction drive source (not shown) that moves the stage 6 along the Y-direction linear guide 613. Linear motors, for example, are used as the X-direction drive source and the Y-direction drive source, and a linear motor stage configuration may be adopted. In the X direction, a standby position for the stage 6 is set on one side away from the irradiation areas EA and EB. A transfer mechanism (not shown) is disposed at the standby position.

[0018] As shown in Fig. 1, the main controller 7 includes a storage unit 71, which stores a main sequence program 72 for sequence control of the entire apparatus, and pixel sequence programs 731 and 732 for sequence control of each pixel mirror 31 of the spatial light modulator 3 in each exposure head 1A, 1B when exposing one substrate W. In this reference example, exposure is performed on an outward path and a return path, so a pixel sequence program 731 for the outward path and a pixel sequence program 732 for the return path are stored. The main sequence program 72 sequentially calls and executes the pixel sequence programs 731 and 732 when exposing each substrate W. Note that it is the modulator controller 32 that actually controls each pixel mirror 31, so the pixel sequence programs 731 and 732 are programs that provide a sequence to the modulator controller 32 so that each pixel mirror 31 is driven according to that sequence.

[0019] Between the standby position and the irradiation area, a camera (not shown) is provided to capture an image of an alignment mark on the substrate W in order to control (align) the formation position of the exposure pattern on the substrate W. The image data captured by the camera is sent to the main controller 7. The main controller 7 controls the formation position of the exposure pattern by executing pixel sequence programs 731 and 732 using the image data as an argument.

[0020] In addition, a rangefinder for autofocusing during exposure (hereinafter referred to as AF rangefinder) 10 is provided between the standby position and the location where each irradiation area is lined up. The AF rangefinder 10 measures the distance to the substrate W when it passes directly underneath, and a laser displacement meter is used, for example. The AF rangefinder 10 is connected to the main controller 7, and sends the measured value to the main controller 7. The main controller 7 feeds this value back to the projection optical system 4 in each exposure head 1A, 1B, and uses it for focus control of the projection lenses 41, 42.

[0021] In order to address the problem of reduced productivity due to higher resolution, the direct imaging exposure apparatus of this reference example has a configuration in which the position at which the irradiation area is formed differs from conventional configurations, and is equipped with offset optical systems 8A and 8B as a means for achieving this. These points will be explained with reference to Figures 5 to 7. Figure 5 is a schematic front view showing the offset optical systems of the reference example, Figure 6 is a schematic perspective view of one offset optical system, and Figure 7 is a schematic plan view showing the action of each offset optical system.

[0022] The offset optical systems 8A and 8B are optical systems that ensure that the irradiation areas EA and EB of the exposure heads 1A and 1B are not directly below the exposure heads 1A and 1B but are shifted (offset) in the X direction. An offset optical system 8 is provided for each exposure head 1A and 1B. For convenience of explanation, of the two rows of exposure heads 1A and 1B arranged in the Y direction, the exposure heads 1A in the row closer to the standby position (left side in FIG. 1) will be referred to as the first row, and the exposure heads 1B farther from the standby position will be referred to as the second row. Furthermore, the offset optical system 8A provided for each exposure head 1A in the first row will be referred to as the first row offset optical system, and the offset optical system 8B provided for each exposure head 1B in the second row will be referred to as the second row offset optical system.

[0023] Each offset optical system 8A, 8B is composed of two mirrors (total reflection mirrors) 81A, 82A, 81B, 82B. Of the two mirrors 81A, 82A, 81B, 82B, the mirrors 81A, 81B, which are located on the optical axis near the exposure heads 1A, 1B, are oriented at 45 degrees to the optical axis and are mirrors that bend the optical axis horizontally toward the exposure heads 1A, 1B in the adjacent row (hereinafter referred to as the first mirror). The other mirrors 82A, 82B are also oriented at 45 degrees to the optical axis and are mirrors that return the horizontally bent optical axis to the vertical direction (hereinafter referred to as the second mirror).

[0024] 5 and 6, each first mirror 81A in the first row offset optical system 8A is a mirror that bends the optical axis toward the second row, and conversely, each first mirror 81B in the second row offset optical system 8B is a mirror that bends the optical axis toward the first row. The first mirrors 81A in the first row offset optical system 8A are arranged along the Y direction and are located at the same height. The first mirrors 81B in the second row offset optical system 8B are also arranged along the Y direction and are located at the same height, the same height as the first mirrors 81A in the first row offset optical system 8A.

[0025] 5, the second mirrors 82A in each first row offset optical system 8A are arranged along the Y direction, and are at the same height and orientation as the first mirrors 81A. The second mirrors 82B in each second row offset optical system 8B are also arranged along the Y direction, and are at the same height and orientation as the first mirrors 81B. Therefore, the second mirrors 82A in each first row offset optical system 8A and the second mirrors 82B in each second row offset optical system 8B are all arranged on the same straight line in the Y direction, and are oriented such that their angles differ by 180 degrees from each other.

[0026] 5 and 7, each irradiation area EA of light from each exposure head 1A in the first row is shifted toward the second row by each first row offset optical system 8A, and each irradiation area EB of light from each exposure head 1B in the second row is shifted toward the first row by each second row offset optical system 8B. In particular, in this reference example, each second mirror 82A in each first row offset optical system 8A and each second mirror 82B in each second row offset optical system 8B are aligned on the same straight line in the Y direction, so each irradiation area EA by each exposure head 1A in the first row and each irradiation area EB by each exposure head 1B in the second row are aligned on the same straight line in the Y direction, as shown in FIG.

[0027] Each micropattern M in each irradiation area EA, EB is the same as that in the above-mentioned Fig. 14. That is, as shown in Fig. 6, although they are arranged in a staggered pattern, the distance between each micropattern M in the Y direction is longer than the diameter φ of the micropattern M, and gap-free exposure cannot be achieved in a single pass. In this reference example, each of the illumination areas EA, EB is rectangular, as shown in Fig. 7 etc. This is due to the arrangement of each pixel mirror 31 in the spatial light modulator 3. Also, in Fig. 7 etc., the longitudinal direction of each of the illumination areas EA, EB coincides with the Y direction, but in many cases it is slightly tilted (by a few degrees) with respect to the Y direction. This is also achieved by disposing the spatial light modulator 3 at a slight tilt.

[0028] Next, the operation of such a direct imaging exposure apparatus of the reference example will be described with reference to Fig. 8. Fig. 8 is a schematic plan view showing the operation of the direct imaging exposure apparatus of the reference example. 8(1), when exposure is performed by the direct imaging exposure apparatus of the reference example, the substrate W is placed on the stage 6 at the standby position by a transfer mechanism (not shown). The stage 6 vacuum-sucks the substrate W and moves it in the X direction toward each of the irradiation areas EA and EB by a stage movement mechanism 61.

[0029] When the stage 6 passes directly below a camera (not shown), the camera photographs the alignment marks on the substrate W and sends the photograph to the main controller 7. Also, when the stage 6 passes directly below an AF rangefinder, the AF rangefinder 10 measures the distance to the substrate W on the stage 6, and the measurement data is sent to the main controller 7.

[0030] Then, when the substrate W on the stage 6 passes through each of the irradiation areas EA and EB on the outward journey, the main controller 7 executes the pixel sequence program 731 for the outward journey, so that each of the irradiation areas EA and EB is irradiated with light of an exposure pattern by each of the exposure heads 11. At this time, photographing data of the alignment marks by the camera is passed, and light of the exposure pattern is irradiated at a predetermined position, and in addition, measurement data by the AF rangefinder 10 is used to control each of the projection lenses 41 and 42, so that exposure is performed in an optimally focused state.

[0031] In this way, exposure is performed on the outward journey, and the substrate W on the stage 6 passes through each of the irradiation areas EA and EB. Then, the stage 6 then performs an inversion operation at the inversion position. As shown in Figure 8(2), the inversion position is a position where the substrate W has completely passed through each of the irradiation areas EA and EB (the rear end of the substrate W has passed through each of the irradiation areas EA and EB) and is slightly further forward.

[0032] As shown in Figure 8(3), at the inversion position, the stage movement mechanism 61 moves (shifts) the stage 6 in the Y direction. The movement distance (hereinafter referred to as the shift distance) at this time is a distance that ensures that the substrate W is exposed without gaps by combining the outgoing and returning passes during exposure on the return path, and is set in advance. The shift distance is indicated by S in Figure 8(3). In addition to the shift distance S, the movement direction of the shift distance S is also set in advance so that exposure is achieved without gaps.

[0033] After the stage 6 has been moved by the shift distance S at the reversal position, it starts moving in the reverse direction toward each of the irradiation areas EA and EB. Then, as it passes through each of the irradiation areas EA and EB, the pixel sequence program 732 for the return pass is executed, and each exposure head 11 performs exposure on the return pass. After the substrate W passes through each of the irradiation areas EA and EB on the return path, the stage 6 returns to the standby position as shown in Fig. 8(4). Then, the substrate W is carried out from the stage 6 by a transfer mechanism (not shown). Then, an unexposed substrate W is placed on the stage 6 again, and the same process is repeated.

[0034] In the direct imaging exposure apparatus of this reference example, the offset optical systems 8A and 8B bring the irradiation areas EA of the first row of exposure heads 1A and the irradiation areas EB of the second row of exposure heads 1B closer together, shortening the travel distance of the stage 6 for the substrate W to completely pass through these irradiation areas EA and EB. In FIG. 7, the travel distance required for the substrate W to completely pass through the irradiation areas EA and EB without offsetting is indicated by D, and the distance required for the substrate W to completely pass through the irradiation areas EA and EB with offsetting is indicated by D' (note that in practice, the length of the substrate W in the X direction is added, but since this is common, it is omitted here). This reduction in travel distance significantly improves productivity. This effect is particularly advantageous in cases where the micropattern M becomes smaller to meet the demand for higher resolution, requiring exposure on both the forward and backward passes. This allows for higher resolution exposure while suppressing a decrease in productivity.

[0035] In this reference example, each offset optical system 8A, 8B is an optical system that offsets each irradiation area EA by the first row of exposure heads 1A and each irradiation area EB by the second row of exposure heads 1B so that they are aligned in a straight line, thereby maximizing the effect of improving productivity. However, even if the alignment is not perfectly straight, the effect of improving productivity can be fully expected. This point will be explained with reference to Fig. 9. Fig. 9 is a schematic diagram showing the effect of improving productivity by each offset optical system.

[0036] Figure 9(1) shows an example in which each irradiation area EA by the first row of exposure heads 1A and each irradiation area EB by the second row of exposure heads 1B are not perfectly aligned, but overlap when viewed in the Y direction. Also, Figure 9(2) shows an example in which each irradiation area EA by the first row of exposure heads 1A and each irradiation area EB by the second row of exposure heads 1B do not overlap, but are offset from a position directly below to a position closer to each other. These configurations also have the effect of improving productivity compared to conventional non-offset configurations, and can be implemented.

[0037] In the above examples, offset optical systems 8A and 8B are provided for each exposure head 1A and 1B in both rows. However, offset optical systems may be provided only in one row. For example, an offset optical system may be provided only in each exposure head 1A in the first row, and no offset optical system may be provided in each exposure head 1B in the second row, with each irradiation area EB located directly below. In this case, productivity is improved by offsetting each irradiation area EA of each exposure head 1A in the first row toward each irradiation area EB of each exposure head 1B in the second row. In this case, the most effective method is to align the irradiation areas EA and EB perfectly, but productivity can also be improved even if they overlap or are close to each other but not overlapping. However, in a configuration in which offset optical systems 8A and 8B are provided on each exposure head 1A and 1B in both rows, the design brings the irradiation areas EA and EB closer to each other from both sides, so even if the irradiation areas EA and EB are overlapped or aligned in a straight line, the offset distance does not become too long and they can be arranged symmetrically, making the design easier.

[0038] Furthermore, the effect of improving productivity is obtained by shortening the distance required for the substrate W to completely pass through each irradiation area EA, EB, so it is not necessarily limited to a configuration in which exposure is performed on both the outbound and return passes. For example, it is also effective when exposure is performed only on the return pass and not on the outbound pass. During exposure, the movement speed of the stage 6 is slowed to ensure a predetermined exposure dose, so the movement distance at low speeds is shortened, shortening the takt time and improving productivity.

[0039] Next, a direct imaging exposure apparatus according to the first embodiment will be described. Figure 10 is a schematic front view showing the main components of the direct imaging exposure apparatus according to the first embodiment. The direct imaging exposure apparatus of the first embodiment differs from the first embodiment in that each of the offset optical systems 8A and 8B has an autofocus function. Specifically, as shown in Fig. 10, each of the offset optical systems 8A and 8B is provided with an optical path length changer 9. In this example, the optical path length changer 9 is a prism pair unit.

[0040] The optical path length changer 9, which is a prism pair unit, is a combination of two prisms 91 and 92 of the same size and shape. In this example, the two prisms 91 and 92, each with a right-angled triangular cross section, are arranged with their inclined faces facing each other. The other face, which forms an acute angle with the inclined face, is perpendicular to the optical axis.

[0041] One of the two prisms 91, 92 is a fixed prism 91, and the other is a movable prism 92. An actuator 93 such as a piezoelectric element is provided on the movable prism 92. The actuator 93 is connected to the main controller 7, and the main controller 7 controls the actuator 93 in accordance with measurement data from the AF rangefinder 10. 10, the optical path length (optical distance) changes. Therefore, by controlling the actuator 93 in accordance with the measurement data of the AF rangefinder 10, an optimal focusing state can be achieved.

[0042] In the first embodiment, the optical path length changer 9 is provided in the offset optical systems 8A and 8B, so there is no need to provide it within the exposure head 1, simplifying the structure within the exposure head 1. In particular, in the first embodiment, the optical path length changer 9 is provided between the first mirror 81 and the second mirror 82, so adjustments during placement are easy. After the first mirror 81, the second mirror 82, and the optical path length changer 9 are housed in a housing and aligned, the housing can be precisely positioned relative to the exposure head 1, making adjustments easy.

[0043] The optical path length changer 9 may be disposed on the optical path between the first mirror 81 and the exposure heads 1A, 1B, or may be disposed on the exit side (below) of the second mirror 82. Furthermore, the optical path length changer 9 may have a configuration other than a prism pair unit.

[0044] Next, a direct imaging exposure apparatus according to a second embodiment will be described below. Figure 11 is a schematic front view showing the main components of the direct imaging exposure apparatus according to the second embodiment. In the direct imaging exposure apparatus of the second embodiment, each of the offset optical systems 8A and 8B has an autofocus function, similar to the first embodiment. The second embodiment differs from the first embodiment in that the autofocus function is realized by moving an offset mirror.

[0045] 11, the second mirror 82A is a movable mirror and is provided with an actuator 83. The actuator 83 is also connected to the main controller 7 and is controlled in accordance with measurement data from the AF rangefinder 10. As a result of the movement of the second mirror 82A by the actuator 83, the optical path length changes and an optimal focusing state is achieved. According to the second embodiment, the focusing state is achieved by moving the optical elements that make up the offset optical system 8, and no optical path length modulator is used. This simplifies the configuration and is expected to reduce costs by reducing the number of parts.

[0046] Next, a direct imaging exposure apparatus according to a third embodiment will be described below. Fig. 12 is a schematic front view showing the main components of the direct imaging exposure apparatus according to the third embodiment. As in the second embodiment, the third embodiment also implements an autofocus function using optical elements that constitute offset optical systems 8A and 8B. As shown in Fig. 12, in the third embodiment, two mirrors 84 and 85 are added to the output side of second mirror 82A. That is, third mirror 84 is provided directly below second mirror 82A at an angle of 45 degrees with respect to the optical axis. Third mirror 84 is oriented 180 degrees differently from second mirror 82A, and bends the optical axis in the opposite direction to the horizontal direction (X direction).

[0047] A fourth mirror 85 is provided at the same height as the third mirror 84. The fourth mirror 85 is also oriented at 45 degrees with respect to the optical axis, and is disposed in the same orientation as the third mirror 84. 12, the optical axis is bent vertically downward by fourth mirror 85 and reaches illumination area EA. The distance between third mirror 84 and fourth mirror 85 is shorter than the distance between first mirror 81A and second mirror 82A, and the distance between first mirror 81A and fourth mirror 85 as viewed in the X direction is the offset distance.

[0048] In the third embodiment, the second mirror 82A and the third mirror 84 are integrally held by a frame (not shown), and this frame is provided with an actuator 86. The actuator 86 is connected to the frame (not shown) so as to move the second mirror 82A and the third mirror 84 integrally in the X direction.

[0049] In the third embodiment, too, the actuator 86 is controlled by a signal from the main controller 7, and the second mirror 82A and the third mirror 84 move together and change their positions in accordance with the measurement data of the AF rangefinder 10. As a result, the optical path length changes, and an optimal focusing state is achieved.

[0050] Compared to the second embodiment, the third embodiment has the advantage that the illumination area EA does not move during autofocus. In the second embodiment, autofocus is achieved by moving only the second mirror 82A, so the position of the illumination area EA also shifts in the X direction. For this reason, it is necessary to change the pixel sequence program 731 according to the drive amount (direction and distance) of the actuator 83 so that exposure is performed at a position that compensates for the shift. The configuration of the third embodiment is superior in that this is not necessary. Although only the exposure heads 1A in the first row are shown in FIGS. 11 and 12, the same configuration is also adopted for the exposure heads 1B in the second row.

[0051] In the above-described reference example and each embodiment, the offset optical systems 8A and 8B are optical systems using mirrors, but prisms may be used instead of mirrors. Each prism is positioned so that its optical axis is bent at a right angle, just like a mirror. In the reference example and each embodiment, exposure was performed on the outbound and return journeys, but this is not essential, and when two round trips are made, exposure may be performed on two outbound journeys or on two return journeys.

[0052] Furthermore, it is not essential for the present invention that the substrate W passes through each of the irradiation areas EA and EB twice, and an apparatus may be used in which gap-free exposure is performed in only one pass. That is, even if the separation distance L of the micropatterns M in the Y direction is smaller than the diameter φ of the micropatterns M as shown in Figure 13 and gap-free exposure is performed in only one pass, a configuration in which the movement distance of the stage 6 required for the substrate W to completely pass through the irradiation areas EA and EB is shortened contributes to improved productivity.

[0053] In addition, in the above-mentioned reference examples and each embodiment, a so-called twin-stage configuration may be adopted. A twin-stage configuration is a configuration in which two stages are provided, and standby positions for the stages are set on both sides of the irradiation areas EA and EB. The stages on both sides alternately move back and forth through the irradiation areas, and the substrates W placed on each stage are alternately exposed. In this case, too, the movement distance for the substrate W to completely pass through each irradiation area EA and EB is shortened by each offset optical system 8A and 8B, improving productivity. [Explanation of symbols]

[0054] 1A exposure head 1B Exposure head 10 AF rangefinder 6 Stages 61 Stage movement mechanism 611 X-direction linear guide 613 Y-direction linear guide 7 Main Controller 72 Main Sequence Program 731 pixel sequence program 732 pixel sequence program 8A Offset Optical System 8B offset optical system 81 First Mirror 82 Second Mirror 9 Optical path length changer W substrate

Claims

1. a stage on which a substrate is placed; a stage moving mechanism that moves a stage on which a substrate is placed from a standby position so that the substrate passes through the irradiation area; an exposure head that accommodates a spatial light modulator that spatially modulates light from a light source and a projection optical system that projects the light pattern formed by the spatial light modulator onto an irradiation area; a direct imaging exposure apparatus that exposes a substrate with a light pattern formed by a spatial light modulator when the substrate passes through an irradiation area, a range finder that measures the distance to the substrate at a position between when the stage is moved from the standby position and when the substrate reaches the irradiation area; an optical path length changer and two mirrors arranged on an optical path between the exposure head and the irradiation area; a controller that controls the optical path length changer in accordance with measurement data from the rangefinder to change the optical path length, thereby achieving a focused state by the projection optical system; 1. A direct imaging exposure apparatus, wherein the two mirrors are mirrors that bend an optical path whose optical path length is changed by an optical path length changer.

2. a stage on which a substrate is placed; a stage moving mechanism that moves a stage on which a substrate is placed from a standby position so that the substrate passes through the irradiation area; an exposure head that accommodates a spatial light modulator that spatially modulates light from a light source and a projection optical system that projects the light pattern formed by the spatial light modulator onto an irradiation area; a direct imaging exposure apparatus that exposes a substrate with a light pattern formed by a spatial light modulator when the substrate passes through an irradiation area, a range finder that measures the distance to the substrate at a position between when the stage is moved from the standby position and when the substrate reaches the irradiation area; a mirror that bends the optical path from the projection optical system in the exposure head to the irradiation area; an actuator that moves a mirror to change the optical path length from the exposure head to the irradiation area; a controller for controlling an actuator in accordance with measurement data from a rangefinder to change the optical path length, thereby achieving a focused state by a projection optical system.

Images