Direct imaging exposure apparatus and stage cleaning method for direct imaging exposure apparatus

Abstract

To provide a direct drawing type exposure device which can sufficiently remove dust even there is irregularity on surfaces of a substrate and a stage, and can improve exposure quality.SOLUTION: When a stage 6 on which a substrate W is mounted is moved by a stage movement mechanism 61, and the substrate W passes through an irradiation area irradiated with light of an exposure pattern by each exposure head 1 provided with spatial light modulators 3, exposure is performed. After a predetermined times of exposure, a main sequence program 72 moves the stage 6 in the state where the substrate W is not mounted, a negative pressure by a suction source 82 acts on and sucks a slit 810 of a nozzle 81 held at a predetermined distance d by a nozzle position adjustment mechanism 83, and dust P attached to a groove 601 and a hole 602 of the stage 6 is sucked and removed.SELECTED DRAWING: Figure 1

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] In such direct imaging exposure apparatuses, there is a problem in that exposure quality is reduced due to the inclusion of foreign matter such as dust and dirt (hereinafter referred to as "dust"). This type of exposure apparatus is installed in a clean room where the required level of cleanliness is maintained, and clean air is blown down inside the apparatus to prevent dust from being transferred to the substrate. However, it is difficult to completely eliminate dust inside the equipment, which is an obstacle to improving exposure quality. One of the causes of dust is that the substrate itself brings dust into the equipment.

[0005] Although substrates are often cleaned with a down-blow of clean air before being carried into the equipment, dust can still easily be carried into the equipment if it adheres to the backside of the substrate or to the handle that carries the substrate. Dust can also be generated when part of the substrate is chipped or when chips occur in structures such as thin films formed in previous processes.

[0006] To remove such dust and prevent deterioration of exposure quality, a sticky roller is sometimes used. The sticky roller is brought into contact with the substrate or the stage on which the substrate is placed and rolled, transferring and removing the dust before exposure. While dust removal using such adhesive rollers is somewhat effective, there is a problem in that it cannot sufficiently remove dust from uneven surfaces such as uneven surfaces or steps. For example, if there is dust at the step between the edge of the substrate placed on the stage and the stage (a step equal to the thickness of the substrate), the dust cannot be transferred properly to the adhesive roller and is likely to remain. Similarly, if the substrate has uneven surfaces or through-holes, it is often difficult to remove the dust using only an adhesive roller.

[0007] Furthermore, even if dust on the substrate or its periphery can be removed, it cannot be removed from the surface of the stage (the backside of the substrate) that is covered by the substrate. While it would be possible to remove the substrate from the stage and roll it over the stage with an adhesive roller, the stage also has irregularities created by vacuum suction to hold the substrate, and any dust that gets caught there cannot be removed with an adhesive roller. For example, if dust gets into a vacuum suction hole and is accidentally released, it may be transferred during exposure, causing a loss of exposure quality.

[0008] The invention of this application was made to solve the above-mentioned problems with direct imaging exposure apparatuses, and aims to enable sufficient dust removal even when the surface of a substrate or stage is uneven, thereby improving exposure quality. [Means for solving the problem]

[0009] In order to solve the above problems, this specification discloses a direct imaging exposure apparatus that forms an exposure pattern using a spatial light modulator and exposes a substrate. This device is an exposure head including a light source and a spatial light modulator; a stage on which a substrate is placed; a stage moving mechanism that moves the stage so that the substrate passes through an irradiation area, which is an area that is irradiated with light of an exposure pattern by the exposure head; It is equipped with: In this direct imaging exposure device, a dust suction means for removing dust adhering to the stage or the substrate placed on the stage by suction using negative pressure; The dust suction means includes a nozzle having a long slit and a suction source connected to the nozzle, the nozzle is positioned a predetermined distance above the stage or the substrate placed on the stage; The nozzle is provided so that its length is in the horizontal direction perpendicular to the direction of movement of the stage. In order to solve the above problem, in a direct imaging exposure apparatus, the nozzle may be provided with a nozzle position adjustment mechanism that adjusts the distance from the stage or the substrate placed on the stage to a predetermined distance. In order to solve the above problems, a direct imaging exposure apparatus is provided. a rangefinder is provided to measure the distance of the stage or the substrate relative to a reference height; The nozzle position adjustment mechanism is equipped with a vertical drive source that moves the nozzle up and down to adjust its position according to the data measured by the rangefinder. It can have the following configuration. In order to solve the above problems, a direct imaging exposure apparatus is provided. The exposure head includes a projection lens that projects the formed exposure pattern onto an irradiation area; an autofocus rangefinder is provided to measure the distance to the surface of the substrate in order to focus the projection of the exposure pattern by the projection lens; The rangefinder is also used as an autofocus rangefinder. It can have the following configuration. In order to solve the above problems, a direct imaging exposure apparatus is provided. A brush made of elastic wire is provided, When the stage is moved by the stage moving mechanism, the brush comes into contact with the stage or the substrate on the stage, causing the wire to bend; The nozzle is positioned so that it can suck up the dust scraped off by the brush wires while the stage is being moved by the stage movement mechanism. It can have the following configuration. In addition, in order to solve the above problem, in a direct imaging exposure apparatus, the brush may be capable of entering a groove or hole in the stage in a bent state when the stage is moved by a stage movement mechanism, or may be capable of abutting against a step between the stage and the substrate. In order to solve the above problem, in a direct imaging exposure device, the nozzle may have a shape that covers the brush except for the tip of the wire. In order to solve the above problem, the direct imaging exposure apparatus may have a configuration in which the nozzle is conductive and grounded. In order to solve the above problems, a direct imaging exposure apparatus is provided. A control unit is provided to control the stage moving mechanism and the dust collecting means, The control unit is equipped with a main sequence program. The main sequence program is programmed to perform a predetermined number of exposure processes by placing a substrate on the stage and moving the stage using the stage movement mechanism, and then perform stage cleaning by suctioning and removing dust by moving the stage using the stage movement mechanism with the nozzle positioned a predetermined distance above the stage without a substrate being placed on the stage. It can have the following configuration. In order to solve the above problems, this specification also discloses a stage cleaning method for a direct imaging exposure apparatus. This method is a method for cleaning the stage in a direct imaging exposure apparatus that includes an exposure head including a light source and a spatial light modulator, a stage on which a substrate is placed, and a stage movement mechanism that moves the stage so that the substrate passes through an irradiation area that is an area irradiated with light of an exposure pattern by the exposure head, and that forms a light pattern by the spatial light modulator to expose the substrate. This stage cleaning method uses a stage having a long slit in the horizontal direction perpendicular to the direction of movement of the stage by the stage movement mechanism. together This method involves positioning a nozzle connected to a suction source a predetermined distance above the stage without a substrate placed on it, and then moving the stage using a stage movement mechanism in this state to suck up and remove dust adhering to the stage. [Effects of the Invention]

[0010] As explained below, in the direct imaging exposure apparatus according to the disclosed invention, dust is sucked and removed by the nozzle, thereby avoiding the problem of exposure quality degradation due to dust. In this case, the nozzle can also remove dust that has gotten into grooves and holes in the stage, so dust that could not be removed by an adhesive roller can be sufficiently removed. This is therefore highly effective in improving exposure quality. The same applies to removing dust from a substrate; dust adhering to the step between the substrate and the stage and dust that has gotten into recesses and through-holes in the substrate can be sufficiently removed, preventing this dust from being accidentally released and degrading exposure quality. Furthermore, in a configuration in which a nozzle position adjustment mechanism is provided to maintain a predetermined distance between the nozzle and the stage or the substrate placed on the stage, an optimal suction force can be applied to the stage or the substrate, thereby optimizing dust collection. Furthermore, in a configuration in which the autofocus rangefinder is also used to measure the vertical position of the stage or substrate relative to the reference height, the structure is simplified and the number of parts is reduced, thereby reducing costs. Furthermore, in a configuration in which a brush is provided that contacts the stage or the substrate on the stage, causing the wire to bend, and the brush is positioned so that it can suck up dust scraped off by the wire, even tightly adhered dust can be sucked up and removed, thereby enhancing the effect of improving exposure quality. In this case, if the brush wires are able to enter the grooves or holes in the stage in a bent state, or to abut against the step between the stage and the substrate, it is possible to more effectively remove dust that has entered the grooves, holes, or steps that could not be removed by dust removal with an adhesive roller, thereby further improving the effect of improving exposure quality. Furthermore, in a configuration in which the nozzle covers the brush except for the tip of the wire, the dust scraped off by the brush can be sucked in and removed more effectively, further improving the exposure quality. Furthermore, in a configuration in which the brush is a charge-removing brush, dust that is electrostatically attracted can also be removed reliably, and in this respect the effect of improving exposure quality is further enhanced. Furthermore, according to an apparatus or method that performs the exposure process a predetermined number of times, and then positions the nozzle a predetermined distance above the stage without placing a substrate on it, and moves the stage using a stage movement mechanism to suck up and remove dust, it is possible to improve exposure quality without significantly reducing productivity, and since dust can be sucked up from the surface of the stage that was covered by the substrate, the effect of improving exposure quality is even greater in this respect. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic front view of a direct imaging exposure apparatus according to a first embodiment. [Figure 2] 1 is a schematic side view of a direct imaging exposure apparatus according to a first embodiment. [Figure 3] 1 is a schematic plan view of a direct imaging exposure apparatus according to a first embodiment. [Figure 4] FIG. 2 is a schematic diagram showing the internal structure of the exposure head. [Figure 5] FIG. 2 is a perspective schematic diagram showing an irradiation area. [Figure 6] 10A and 10B are schematic front views showing adjustment of nozzle positions by a nozzle position adjustment mechanism. [Figure 7] 5A to 5C are schematic front views showing the dust suction operation in the device of the first embodiment. [Figure 8] FIG. 10 is a schematic side view showing an example in which two vertical drive sources are independently controlled. [Figure 9] FIG. 10 is a schematic front view of the main part of a direct imaging exposure device according to a second embodiment. [Figure 10] FIG. 10 is a schematic side view of the main part of a direct imaging exposure apparatus according to a second embodiment. [Figure 11] 10 is a front schematic view showing the operation of the dust suction means in the second embodiment. FIG. [Figure 12] FIG. 10 is a schematic front view showing the main parts of a direct imaging exposure device according to a third embodiment. [Figure 13] FIG. 10 is a schematic side view showing the main parts of a direct imaging exposure apparatus according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, modes (embodiments) for carrying out the invention of this application will be described. 1 to 3 are schematic diagrams of a direct imaging exposure apparatus according to the first embodiment, with FIG. 1 being a schematic front view, FIG. 2 being a schematic side view, and FIG. 3 being a schematic plan view. 1 and 2 is a direct imaging exposure apparatus that forms a light pattern using a spatial light modulator to expose a substrate. Specifically, this apparatus is equipped with an exposure head 1 including a light source and a spatial light modulator, a stage 6 on which a substrate W is placed, and a stage movement mechanism 61.

[0013] The exposure head 1 is cylindrical overall, is positioned vertically, and emits light downward. Figure 4 is a schematic diagram showing the internal structure of the exposure head. As shown in Figure 4, the exposure head 1 is equipped with 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.

[0014] 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 the resist film is often in the visible short wavelength range to the ultraviolet range, and 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 outputs coherent light, and for this reason a laser light source 2 is preferably used. For example, a gallium nitride (GaN) semiconductor laser is used.

[0015] In this embodiment, 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 a 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 arranged mirrors is, for example, 1024 x 768.

[0016] The spatial light modulator 3 includes a modulator controller 32 that controls each pixel mirror 31. The exposure apparatus of this embodiment includes a main controller 7 that controls the entire apparatus. 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.

[0017] As shown in Fig. 4, the exposure head 1 is equipped with an illumination optical system 5 that illuminates the spatial light modulator 3 with light from the light source 2. In this embodiment, the illumination optical system 5 includes an optical fiber 51. In order to form an image with higher illuminance, one exposure head 1 is equipped with multiple 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.

[0018] 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.

[0019] 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 consisting of a large number of tiny lenses arranged in a rectangular lattice pattern. Each lens element corresponds one-to-one to each pixel mirror 31 of the spatial light modulator 3.

[0020] In the exposure head 1 described above, 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 the 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 the predetermined exposure pattern is irradiated onto the irradiation area. A plurality of such exposure heads 1 are provided. As shown in Fig. 3, eight exposure heads 1 are provided in this embodiment. The eight exposure heads 1 form a single exposure pattern as a whole. Each exposure head 1 has the same configuration.

[0021] 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. The stage movement mechanism 61 includes a linear guide 60 arranged throughout the irradiation area, and a drive source (not shown) that moves the stage 6 linearly along the linear guide 60. A linear motor, for example, is used as the drive source, and a linear motor stage 6 configuration can be adopted. The direction in which the linear guide 60 extends is the transport direction. Hereinafter, this direction will be referred to as the X direction, and the horizontal direction perpendicular to the X direction will be referred to as the Y direction. In addition, a standby position for the stage 6 is set on one side away from the irradiation area in the transport direction. A transfer mechanism (not shown) is disposed at the standby position.

[0022] The irradiation area will be further explained with reference to Figure 5. Figure 5 is a perspective schematic diagram showing the irradiation area. In Figure 5, an area E (hereinafter referred to as an individual area) onto which light can be irradiated by one exposure head 1 is indicated by a square frame. A collection of individual areas E constitutes the irradiation area. 5 (X direction), the substrate W is irradiated with light at each individual area E. At this time, the two rows of exposure heads 1 are arranged offset from each other, so exposure is performed without gaps even in the horizontal direction (Y direction) perpendicular to the movement direction.

[0023] As shown enlarged in Figure 5, each individual area E is actually a collection of minute irradiation patterns (hereinafter referred to as "minute patterns") M. One minute pattern M is a pattern created by one pixel mirror 31. The substrate W placed on the stage 6 moves through the irradiation area as the stage 6 moves, and the minute patterns M are turned on and off in a predetermined sequence in accordance with the timing of this movement. In this way, the desired exposure pattern is formed on the substrate W.

[0024] 1, the main controller 7 is equipped with a storage unit 71, which stores a main sequence program 72 for sequence control of the entire apparatus, and a pixel sequence program 73 for sequence control of each pixel mirror 31 of the spatial light modulator 3 in each exposure head 1 when exposing one substrate W. The main sequence program 72 calls and executes the pixel sequence program 73 when exposing each substrate W. Since it is the modulator controller 32 that actually controls each pixel mirror 31, the pixel sequence program 73 is a program that provides a sequence to the modulator controller 32 so that each pixel mirror 31 is driven in accordance with that sequence.

[0025] Between the standby position and the irradiation area, a camera (not shown) is provided for capturing 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 captured image data from the camera is sent to the main controller 7. The main controller 7 controls the formation position of the exposure pattern by executing a pixel sequence program 73 using the captured image data as an argument.

[0026] In order to improve exposure quality, the direct imaging exposure apparatus of this embodiment is equipped with a dust removal means of a different type than conventional ones. That is, the apparatus of the embodiment is equipped with a dust collection means that sucks and removes dust. The dust collection means is a means for sucking and removing dust adhering to the stage 6 or the substrate W on the stage 6 by using negative pressure. 1, the dust suction means includes a nozzle 81 having a slit 810, and a suction source 82 connected to the nozzle 81. A blower suction device such as a ring blower can be used as the suction source 82. The negative pressure created by the suction source 82 is, for example, about -5 kPa to -20 kPa relative to atmospheric pressure.

[0027] 2 and 3, nozzle 81 is a long member that has a slit 810 extending in the longitudinal direction and that sucks in dust through slit 810. As shown in FIGS. 2 and 3, nozzle 81 is arranged along the width direction (Y direction) of stage 6, and is slightly longer than the width (length in the Y direction) of stage 6, and slit 810 is also slightly longer than the width of stage 6. The width of slit 810 (length in the X direction, indicated by w in FIG. 1) is approximately 0.5 mm to 3.0 mm. Nozzle 81 is installed with slit 810 facing downward. Nozzle 81 is preferably lightweight, and from this point of view, it is made of a resin such as PVC (polyvinyl chloride) resin or PMMA (acrylic) resin. It may also be made of a metal such as aluminum.

[0028] The nozzle 81 is connected to a suction source 82 by a suction hose 821. A valve 822 is provided in the suction path, and the valve 822 is opened and closed by a signal from the main controller 7. Note that air is released from the suction source 82 as suction occurs, but the suction source 82 is either installed outside the clean room or is configured to release air through a filter such as a HEPA filter, so that the sucked dust is not released again into the clean room.

[0029] The dust suction means also includes a nozzle position adjustment mechanism 83 for positioning the nozzle 81 at an optimum position relative to the substrate W or the stage 6. In this embodiment, the nozzle position adjustment mechanism 83 is a mechanism that moves the nozzle 81 up and down to maintain a position a predetermined distance above the substrate W or the stage 6. The device also has an upper frame (not shown) for mounting each component. The nozzle position adjustment mechanism 83 is fixed to the upper frame, and the nozzle 81 is suspended via the vertical position adjustment mechanism 83.

[0030] The vertical position adjustment mechanism 83 includes a vertical drive source 831. As shown in FIGS. 2 and 3, the vertical drive source 831 is connected to both ends of the nozzle 81. As the vertical drive source 831, for example, a servo motor is used. The vertical drive source 831 includes a mechanism that converts rotation into vertical linear motion using, for example, a ball screw, and both ends of the nozzle 81 are connected to the vertical drive source 831 via this mechanism. Therefore, by operating the vertical drive sources 831 on both sides in synchronization, the nozzle 81 can be raised and lowered. The nozzle 81 is attached while being held by the vertical drive sources 831 on both sides, and the vertical drive sources 831 on both sides are fixed to the upper frame.

[0031] The apparatus is equipped with a rangefinder that measures the distance from a reference height position to the substrate W or the stage 6, and the nozzle position adjustment mechanism 83 is a mechanism that controls the vertical drive source 831 in accordance with the measured distance. This point will be explained using Figure 6. Figure 6 is a front schematic view showing adjustment of the nozzle position by the nozzle position adjustment mechanism.

[0032] In this embodiment, the distance from the reference height position to the substrate W or the stage 6 is measured by a rangefinder 10 used for autofocusing during exposure by each exposure head 1 (hereinafter referred to as an AF rangefinder). As shown in Figures 1 and 6, the AF rangefinder 10 is provided in a position close to the irradiation area. In this embodiment, the stage 6 on which the substrate W is placed passes through the irradiation area once, and then exposure is performed as it returns (on the return trip). For this reason, the AF rangefinder 10 is attached in a position opposite the standby position with respect to the irradiation area. A laser displacement meter, for example, is used as the AF rangefinder 10.

[0033] 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 1 and uses it for focus control of the projection lenses 41, 42. In addition, the main controller 7 sends the measurement value to the nozzle position adjustment mechanism 83, which positions the nozzle 81 at an optimum position in the vertical direction in relation to the measured position of the substrate W or stage 6. That is, the height position of the nozzle 81 is calculated according to the measurement value so that the distance between the upper surface of the substrate W or the upper surface of the stage 6 and the lower surface of the nozzle 81 is a predetermined distance d, and each vertical drive source 831 is controlled to position the nozzle 81 at that position.

[0034] 6 shows, as an example, a state in which dust suction is performed to remove dust from the surface of the stage 6 without the substrate W present. As shown in Fig. 6, the nozzle position adjustment mechanism 83 synchronously operates the up and down drive sources 831 on both sides, and controls (servo controls) the distance between the upper surface of the stage 6 and the lower end of the nozzle 81 to a predetermined distance d according to the measurement value of the AF rangefinder 10.

[0035] The predetermined distance d is preferably about 0.5 mm to 3.0 mm. A smaller predetermined distance d is preferable because it allows dust to be sucked in with a weaker suction force. However, if the predetermined distance d is shorter than 0.5 mm, depending on the precision of the stage movement mechanism 61, the nozzle 81 may collide with the stage 6, which could damage the nozzle 81 or cause fragments to become a source of dust. If the predetermined distance d is longer than 3.0 mm, a greater suction force is required to sufficiently suck in dust, which could result in a larger structure and the possibility of unnecessary stirring up of surrounding dust. For this reason, the predetermined distance d is preferably 0.5 mm to 3.0 mm.

[0036] The same applies when dust collection is performed with the substrate W placed on the stage 6, but the nozzle position adjustment mechanism 83 controls the vertical drive source 831 so that a predetermined distance d is maintained based on the highest position of the heights of each part of the substrate W measured by the AF rangefinder 10. That is, there may be structures built into the substrate W due to previous processing, causing unevenness, and in such cases the predetermined distance d is controlled using the value of the rangefinder when the highest part is measured. When dust is vacuumed with the substrate W placed on the stage 6, it is preferable that the negative pressure in the slit 810 of the nozzle 81 generated by the suction source 82 does not become lower than the negative pressure for vacuum suction of the substrate W on the stage 6. This is because if the pressure becomes lower than the negative pressure for vacuum suction, the substrate W may become misaligned during dust vacuuming.

[0037] The main sequence program 72 implemented in the main controller 7 includes a module for controlling the operation of the dust collection means. In this embodiment, the main sequence program 72 is a sequence for operating the dust collection means after a predetermined number of exposure processes (a predetermined number of times) have been performed.

[0038] The operation of the direct imaging exposure apparatus according to the embodiment having the above configuration will be described below with reference to Fig. 7. Fig. 7 is a schematic front view showing the dust collection operation in the apparatus according to the first embodiment. When exposure is performed using the direct imaging exposure apparatus of this embodiment, the substrate W is placed on the stage 6 at a standby position by a transfer mechanism (not shown) and vacuum-adsorbed. The stage 6 on which the substrate W is placed is moved by a stage movement mechanism 61 and heads toward the irradiation area. At this time, a camera (not shown) takes an image of the alignment mark on the substrate W and sends the image to the main controller 7. After the stage 6 passes through the irradiation area once, it turns around and heads toward the irradiation area. At this time, 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.

[0039] On the return path, when the substrate W on the stage 6 passes through the irradiation area, the main controller 7 executes the pixel sequence program 73 so that the irradiation area is irradiated with light of an exposure pattern by each exposure head 1. At this time, photographed data of the alignment mark by the camera is passed, and light of the exposure pattern is irradiated at a predetermined position, and in addition, measurement data from the AF rangefinder 10 is used to control each projection lens 41, 42, so that exposure is performed in an optimally focused state. After exposure on the return path, the stage 6 is returned to the standby position, and a transfer mechanism (not shown) carries the substrate W out of the stage 6. Then, an unexposed substrate W is placed on the stage 6 again, and the same process is repeated.

[0040] After exposure processing has been performed on a predetermined number of substrates W in this manner, the main sequence program 72 executes a dust collection processing sequence. That is, the stage 6 is moved by the stage movement mechanism 61 without a substrate W placed on it, and passes through the irradiation area. The AF rangefinder 10 then measures the distance to the upper surface of the stage 6, and sends the measurement data to the main controller 7. The main controller 7 sends this measurement data to the nozzle position adjustment mechanism 63 to control the vertical drive source 831 so that the lower end of the nozzle 81 is at a height of a predetermined distance d from the upper surface of the stage 6. The suction source 82 is operated in advance, but the valve 822 is kept closed.

[0041] Then, just before the front end in the traveling direction of stage 6 moving on the return path reaches a position directly below nozzle 81, main controller 7 opens valve 822 so that suction pressure (negative pressure) from suction source 82 acts on nozzle 81. In this state, stage 6 passes the position directly below nozzle 81, and at this time, dust present on stage 6 is sucked into nozzle 81 and removed. More specifically, as shown in FIG. 7 , in addition to dust present on flat areas of the top surface of stage 6, dust P present inside groove 601 and dust P that has entered vacuum suction holes 602 are sucked into nozzle 81 and removed.

[0042] When the rear end of the stage 6 in the traveling direction passes the position directly below the nozzle 81, the main controller 7 closes the valve 822 and stops suction. Thereafter, as described above, the substrate W is placed on the stage 6, and the single wafer processing is repeated. When removing dust adhering to the substrate W, the dust suction means is operated in the same manner with the substrate W placed on the stage 6. In this case, after passing the irradiation area and measuring the distance with the AF rangefinder 10, the stage 6 turns around, and as it passes the irradiation area without performing exposure on the return trip and moves toward the standby position, dust suction is performed directly below the nozzle 81. The stage 6 then turns around again and heads toward the irradiation area, and exposure is performed on the outward or return trip. This results in two round trips.

[0043] In the direct imaging exposure apparatus according to the embodiment of the above operation, dust is sucked and removed by the dust suction means, thereby avoiding the problem of exposure quality degradation due to dust. In this case, the nozzle 81 can also remove dust that has gotten into the grooves 601 and holes 602 of the stage 6, so dust that could not be removed by an adhesive roller can be sufficiently removed. This is also true when removing dust from the substrate W; dust adhering to the step between the substrate W and the stage 6 and dust that has gotten into recesses and through-holes in the substrate W can be sufficiently removed, preventing this dust from being accidentally released and degrading exposure quality. The "predetermined number of times" which is the interval at which stage cleaning is performed may be 1. In other words, stage cleaning may be performed every time one substrate W is processed.

[0044] Furthermore, since the nozzle position adjustment mechanism 63 is provided, the nozzle 61 can be positioned at an optimum position relative to the stage 6 or the substrate W, and an optimum suction force can be applied to the stage 6 or the substrate W. This allows for optimum dust collection. In this case, the AF rangefinder 10 is also used to measure the vertical position of the stage 6 or the substrate W relative to the reference height, so the structure is simplified and the number of parts is reduced, resulting in cost reduction.

[0045] In the device of the first embodiment, the vertical drive sources 831 that move the nozzle 81 up and down may be operated synchronously or independently. In this case, a suitable control example is control to place the nozzle 81 in an appropriately oblique position. This point will be explained with reference to Fig. 8. Fig. 8 is a side schematic view showing an example of independently controlling two vertical drive sources 831.

[0046] 8, by independently controlling two vertical drive sources 831 and slightly shifting the height position of one end of the nozzle 81 from the height of the other end, the nozzle 81 will assume a slightly oblique position. In this way, if the stage 6 or substrate W assumes a slightly oblique position, the nozzle 81 can be correspondingly positioned obliquely, thereby reducing the variation in the distance between the nozzle 81 and the stage 6 or substrate W in the longitudinal direction of the nozzle 81 and approaching the predetermined distance d. This reduces variation in the dust suction action, enabling more reliable dust removal.

[0047] 3, multiple AF rangefinders 10 are provided lined up in the Y direction. Therefore, it is possible to measure variations in the height position of the stage 6 or the height position of the substrate W in the Y direction, and this variation indicates that the stage 6 or the substrate W is in an oblique position. Therefore, by identifying the oblique position using the measurement data from each AF rangefinder 10 and independently controlling the two up / down drive sources 831 accordingly, dust collection can be performed more reliably.

[0048] The stage 6 is processed and manufactured with good flatness, and is moved by a stage movement mechanism 61 with good linearity, so cases like the one shown in Figure 8 are rare, but the substrate W may be slightly warped or distorted. Even if the substrate is slightly warped or distorted, it may not be considered a defective product, and dust collection may be performed in the state shown in Figure 8. Therefore, it is advantageous to be able to control the two vertical drive sources 831 to position the nozzle 81 at an appropriate angle. The control to maintain the oblique posture is performed within the range of allowable gaps in the connection structure of the two vertical drive sources 831 to the nozzle 81. Alternatively, an elastic hinge or the like may be appropriately provided in the connection structure to the nozzle 81 to enable vertical drive while maintaining the oblique posture.

[0049] As the vertical drive source 831, an electric actuator such as a servo motor or a fluid pressure actuator such as an air cylinder may be used. When a fluid pressure actuator is used, the vertical position can be adjusted by appropriately arranging stoppers. The nozzle 81 can be controlled to assume an oblique posture by setting the left and right stoppers at different height positions.

[0050] Furthermore, it is not essential that the vertical drive sources 831 be provided at both ends of the nozzle 81; a single vertical drive source may be provided in the center of the length direction (Y direction) to move the nozzle up and down. In this case, the vertical drive source may be electric or hydraulic. When a drive source is provided in the center to move the nozzle up and down, linear guides are provided at both ends, but if the nozzle 81 is not particularly long, linear guides may not be provided and the accuracy of the vertical position may be ensured by the linearity of the vertical drive source. Alternatively, a single linear guide may be provided in the center, and products that combine an air cylinder with a linear guide provided behind it as a unit are commercially available, so this can also be used.

[0051] Next, a direct imaging exposure apparatus according to a second embodiment will be described. Figures 9 and 10 are schematic diagrams of the main parts of the direct imaging exposure apparatus according to the second embodiment, with Figure 9 being a schematic front view and Figure 10 being a schematic side view. As shown in Figures 9 and 10, the direct imaging exposure device of the second embodiment also has a dust collection means, which includes a nozzle 81 and a suction source 82 connected to the nozzle 81 via a suction hose 821.

[0052] In the second embodiment, in order to enhance the dust suction action of the dust suction means, a brush 84 is employed. As shown in Figures 9 and 10, the nozzle 81 is a hollow member, and the brush 84 is disposed inside the nozzle 81. In this embodiment as well, the nozzle 81 is long in the width direction (Y direction) of the stage 6. A band-shaped holder 841 extending in the same direction as the nozzle 81 is fixed inside the nozzle 81, and the brush 84 is attached to the lower surface of the holder 841.

[0053] 9 and 10, the brush 84 has a length that passes through the suction port 810 of the nozzle 81 and protrudes slightly from the suction port. In other words, the brush 84 is covered by the nozzle 81 except for its tip. Each wire of the brush 84 has a moderate elasticity, and the protruding length of the brush 84 in its free state (indicated by L in FIG. 9) is slightly longer than the predetermined distance d described above. Therefore, when the nozzle 81 is disposed so as to maintain the predetermined distance d from the stage 6 or the substrate W, each wire of the nozzle 81 is slightly bent. The protruding length L is set to be, for example, approximately 1 mm to 3 mm longer than the predetermined distance d.

[0054] Such brush 84 is preferably a so-called static elimination brush. That is, it is preferable that each wire of brush 84 is conductive and attached in a grounded state. For example, the holder may be made of metal, and brush 84 may be grounded via the holder as shown in FIG. 9. The material for brush 84, which is a static elimination brush, may be selected appropriately from amorphous metal fiber, stainless steel fiber, carbon fiber, Thunderon, etc.

[0055] The operation of the dust suction means equipped with the brush 84 will be described with reference to Fig. 11. Fig. 11 is a schematic front view showing the operation of the dust suction means in the second embodiment. Fig. 11 shows dust suction for the stage 6 as an example. In the second embodiment as well, the brush 84 is positioned above the stage 6 at a predetermined distance d relative to the stage 6 when, for example, the substrate W is not present, and the stage 6 is moved in this state by the stage movement mechanism 61. At this time, as shown in Fig. 11 , each wire of the brush 84 has a protruding length L in its free state that is longer than the predetermined distance d, and therefore, due to its elasticity, enters the grooves 601 and holes 602 of the stage 6 and efficiently scrapes out the dust P adhering to the inside of the grooves 601 and holes 602. The scraped-out dust P is sucked through the slits 810, enters the nozzle 81, and is discharged through the suction hose 821.

[0056] As described above, according to the second embodiment, dust P in the grooves 601 and holes 602, which could not be removed by conventional dust removal using an adhesive roller, is scraped out by the brush 84 and efficiently removed. This further improves the exposure quality. The same applies to dust adhering to step portions of the substrate W. In the second embodiment, the brush 84 is a static elimination brush, which eliminates static electricity from the stage 6 and dust. This makes it possible to sufficiently remove dust that is electrostatically attracted to the stage 6. The same is true for dust P that is attached to the inside of the grooves 601 and holes 602; static elimination makes it easier to scrape out the dust P, allowing for more efficient dust collection, further enhancing the above-mentioned effect.

[0057] The brush 84 protrudes from the slit 811 of the nozzle 81 and is covered by the nozzle 81 except for its tip, which is significant in that it allows the dust scraped out by the brush 84 to be reliably removed without scattering. A similar structure could be adopted, in which the brush 84 is positioned in front of the nozzle 81. "In front" means the position that first faces the stage 6 or the substrate W when the stage 6 or the substrate W moves. Even with this structure, dust can be removed from the grooves 601 and the holes 602, but if the brush 84 scoops out dust and scatters it outside the area that can be sucked up by the nozzle 81, the dust cannot be sucked up. With the structure in which the brush 84 extends through the slit 811 of the nozzle 81 as described above, this problem does not occur, and the dust is reliably sucked up and removed. As another structure, it is conceivable to fix the brush 84 to the lower surface (the surface where the slit 811 is provided) of the nozzle 81. Although this structure is also acceptable, a structure in which the brush 84 is disposed through the suction port is more effective.

[0058] Next, a direct imaging exposure apparatus according to a third embodiment will be described. Figures 12 and 13 are schematic diagrams showing the main components of the direct imaging exposure apparatus according to the third embodiment, with Figure 12 being a schematic front view and Figure 13 being a schematic side view. The third embodiment also includes a dust suction means, which includes a nozzle 81 and a suction source 82 connected to the nozzle 81 via a suction hose 821. In the third embodiment, the nozzle 81 includes wheels 85, as shown in Figures 12 and 13 .

[0059] As shown in Figures 12(1) and 13, two wheels 85 are provided on both ends of the nozzle 81 in the Y direction. However, as shown in Figure 12(2), there may be cases where wheels 85 are also provided on both ends in the X direction, making a total of four. Although not shown, each wheel 85 is fitted with a tire made of a material that suppresses dust generation. These wheels 85 are employed as a simple structure for maintaining the predetermined distance d. That is, the axle of each wheel 85 is fixed inside the nozzle 81, and the fixed position is such that the protruding length of the wheel 85 from the underside of the nozzle 81 coincides with the predetermined distance d. Therefore, as shown in FIGS. 12 and 13 , when each wheel 85 is in contact with the stage 6, the nozzle 81 maintains the predetermined distance d from the stage 6. When the stage 6 moves, the distance d is maintained and each wheel 85 rolls (following rotation). This provides a sufficient suction effect on dust adhering to the stage 6. At this time, because the predetermined distance d is maintained by each wheel 85, there is no need for feedback control of the position of the nozzle 81, which is convenient.

[0060] The structure of the third embodiment may also be applied to dust removal from the substrate W, but there are cases where it is not preferable to have the wheels 85 contact the substrate W. In such cases, a structure can be adopted in which each wheel 85 contacts the stage 6 outside the substrate W. In this case, the protruding length of each wheel 85 is set to a length obtained by adding the thickness of the substrate W to the predetermined distance d. In the third embodiment, the brush 84 can be used in combination with the nozzle 81 as in the second embodiment, and it is preferable that the brush 84 be arranged inside the nozzle 81 and project through the suction port.

[0061] In each of the above-described embodiments, the nozzle 81 is disposed between the standby position and the irradiation area, but it may also be disposed on the opposite side of the irradiation area from the standby position. In this case, the stage 6 or the substrate W passes through the irradiation area once, and then dust is collected on the opposite side. With this configuration, even when dust is collected on the substrate W, exposure can be performed as the substrate passes through the irradiation area on the return trip, so there is no need to make two round trips.

[0062] In both the above-described modified examples, it is preferable to avoid vacuuming while exposure is occurring, i.e., to avoid simultaneous exposure and vacuuming. This is because vacuuming can cause vibrations, and even slight vibrations can affect exposure. For example, when vacuuming a substrate W in a configuration in which the nozzle 81 is positioned close to the irradiation area, the nozzle 81 scans the substrate W as the stage 6 moves. However, it is possible that the front portion of the substrate W reaches the irradiation area after vacuuming has finished. In this case, exposure is performed on the front portion while vacuuming is being performed on the rear portion. This configuration is not preferable because it can be affected by vibrations. To avoid this, the nozzle 81 can be positioned away from the irradiation area, and the front end of the substrate W enters the irradiation area for exposure after vacuuming has been completed up to the rear end.

[0063] In each of the above embodiments, the AF rangefinder 10 is also used as the rangefinder for exposure, but a rangefinder may be provided separately from the AF rangefinder 10. For example, a possible configuration is to provide a rangefinder immediately after the standby position, measure the distance here, and have the nozzle 81 scan the stage 6 or substrate W just before the irradiation area to perform dust collection.

[0064] Furthermore, a rangefinder is not essential for implementing the present invention, and there are cases where a rangefinder is not necessary. For example, when only dust suction is performed on the stage 6, and the height position of the upper surface of the stage 6, which is moved by the stage movement mechanism 61, is always constant and stable, it is sufficient to position the nozzle 81 at a position that is a predetermined distance d from that position, and no rangefinder is particularly necessary. When dust suction is performed on the substrate W, if there is no significant change in the thickness of the substrate W, or if there is a change but the degree of difference does not affect the dust suction function, it is sufficient to position the nozzle 81 at a certain height position, and no rangefinder is necessary. Furthermore, in these cases, it may not be necessary to adjust the position of the nozzle 81, and there may be cases where the nozzle position adjustment mechanism 83 is not provided (when the nozzle 81 is provided in a fixed position).

[0065] It should be noted that a vacuum pump can be used as the suction source 82, in addition to a blower such as a ring blower. In this case, a vacuum pump that exhausts the vacuum suction holes of the stage 6 can also be used in combination.

[0066] In each of the above-described embodiments, the direct imaging exposure apparatus may have a so-called twin-stage configuration. A twin-stage configuration is a configuration in which two stages are provided, with standby positions for the stages on either side of an irradiation area. The two stages alternately reciprocate through the irradiation area, and the substrates W placed on each stage are alternately exposed. In this case, the dust collection means may be shared to collect dust from both stages and the substrates W on both stages, or may be provided separately to collect dust from each stage and the substrates on each stage. [Explanation of symbols]

[0067] 1 exposure head 10 AF rangefinder 6 Stages 601 Groove 602 Vacuum suction hole 61 Stage movement mechanism 7 Main Controller 72 Main Sequence Program 81 nozzle 82 Suction source 821 Suction hose 822 Valve 83 Nozzle position adjustment mechanism 831 Vertical drive source 84 Brushes 85 wheels W substrate P dust

Claims

1. A direct imaging exposure apparatus that forms an exposure pattern using a spatial light modulator and exposes a substrate, an exposure head including a light source and a spatial light modulator; a stage on which a substrate is placed; a stage moving mechanism that moves the stage so that the substrate passes through an irradiation area, which is an area that is irradiated with light of an exposure pattern by the exposure head; It is equipped with a dust suction means for removing dust adhering to the stage or the substrate placed on the stage by suction using negative pressure; The dust suction means includes a nozzle and a suction source connected to the nozzle, A brush made of elastic wire is provided, When the stage is moved by the stage moving mechanism, the brush comes into contact with the stage or the substrate on the stage, causing the wire to bend; The nozzle is positioned so that it can suck up dust scraped off by the brush wires while the stage is being moved by the stage moving mechanism, The nozzle has a long slit, the nozzle is positioned a predetermined distance above the stage or the substrate placed on the stage; The nozzle is provided so that the length direction of the slit is horizontal and perpendicular to the direction of movement of the stage. the nozzle has a shape that covers the brush except for the tip of the wire, A direct imaging exposure apparatus characterized in that the length of the wire projecting from the nozzle is 1.5 mm or more and 6 mm or less.

2. 2. A direct imaging exposure apparatus according to claim 1, wherein the nozzle is provided with a nozzle position adjustment mechanism for adjusting the distance from the stage or the substrate placed on the stage to the predetermined distance.

3. a rangefinder is provided to measure the distance of the stage or the substrate relative to a reference height; 3. A direct imaging exposure apparatus according to claim 2, wherein said nozzle position adjusting mechanism includes a vertical drive source for adjusting the position of said nozzle by moving said nozzle vertically in accordance with data measured by a range finder.

4. the exposure head includes a projection lens that projects the formed exposure pattern onto an irradiation area; an autofocus rangefinder is provided to measure the distance to the surface of the substrate in order to focus the projection of the exposure pattern by the projection lens; 4. A direct imaging exposure apparatus according to claim 3, wherein the rangefinder also serves as a rangefinder for autofocusing.

5. 5. A direct imaging exposure apparatus as described in any one of claims 1 to 4, wherein the brush is capable of entering a groove or hole in the stage in a bent state when the stage is moved by the stage moving mechanism, or capable of abutting against a step between the stage and the substrate.

6. 6. A direct imaging exposure apparatus according to claim 1, wherein said nozzle is conductive and grounded.

7. a control unit is provided to control the stage moving mechanism and the dust suction means, The control unit is equipped with a main sequence program.

7. The direct imaging exposure apparatus according to claim 1, wherein the main sequence program is programmed to perform a predetermined number of exposure processes in which a substrate is placed on the stage and the stage is moved by the stage movement mechanism, and then to perform stage cleaning in which dust is sucked and removed by positioning the nozzle a predetermined distance above the stage with no substrate placed on the stage and moving the stage by the stage movement mechanism.

8. A method for cleaning a stage in a direct imaging exposure apparatus that includes an exposure head including a light source and a spatial light modulator, a stage on which a substrate is placed, and a stage movement mechanism that moves the stage so that the substrate passes through an irradiation area that is an area that is irradiated with light of an exposure pattern by the exposure head, and that forms an exposure pattern by the spatial light modulator to expose the substrate, comprising: A stage cleaning method for a direct imaging exposure apparatus, characterized in that a nozzle (excluding a nozzle attached to a member that adsorbs and fixes a substrate for carrying in the substrate) that has a long slit in the horizontal direction perpendicular to the direction of movement of the stage by the stage movement mechanism and that is connected to a suction source is positioned a predetermined distance above the stage with no substrate placed on it, and the stage is moved in this state by the stage movement mechanism, thereby sucking and removing dust that has adhered to the stage.

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