Direct exposure device and substrate exposure method

Abstract

The present invention provides a direct exposure device and a substrate exposure method. The flatness of the exposure area can be well maintained, and even with an exposure optical system with a shallow depth of focus, two surfaces of a substrate capable of high-resolution pattern exposure can be simultaneously exposed. The direct exposure device comprises: a pair of exposure units, which are arranged opposite to each other with a substrate sandwiched therebetween; and a pair of adsorption portions, which adsorb the surface of the substrate opposite to the exposure area in the exposure area of ​​each exposure unit.

Description

Technical Field

[0001] The present invention relates to a direct exposure device for drawing a predetermined pattern on the front and back sides of a substrate and an exposure method for the substrate. Background Art

[0002] In the photolithography process of manufacturing substrates such as printed wiring boards, semiconductor wafers, LCD glass substrates, LED substrates, and organic EL substrates, there is a known direct exposure device (maskless exposure device) that does not use a photomask. According to this direct exposure method, since a photomask is not required, it is advantageous in terms of cost, and high-precision exposure can be performed.

[0003] Furthermore, when it is necessary to draw both the front and back sides of the substrate, one side is drawn first, and then the substrate is turned over and the other side is drawn. In particular, in a printed wiring board, circuit patterns are generally made on both sides of the substrate. However, when drawing both the front and back sides of the substrate, the processing efficiency cannot be improved because the process of turning the substrate over is required. In addition, the alignment accuracy of the front and back sides of the substrate may be reduced.

[0004] Therefore, there is an increasing demand for using a direct exposure device to expose both sides of a substrate at the same time. For example, Patent Document 1 describes a device that exposes a body to be drawn (substrate) by holding an upper holding frame and a lower holding frame, and irradiates a laser beam to both sides through a through-hole glass. In addition, Patent Document 2 describes a device that exposes both sides while holding a substrate by upper and lower clamping parts.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-122597

[0006] Patent Document 2: Japanese Patent Application Publication No. 2014-190987

[0007] The direct exposure device has a tendency that the depth of focus of the exposure optical system becomes shallower as the resolution of the exposed pattern becomes higher. Therefore, the height difference (flatness) of the exposure area is required to be within a few μm. In the device described in Patent Document 1, since the substrate is held by a hollow square frame-shaped holding frame, it is possible to expose not only from the front side of the substrate but also from the back side of the substrate. However, there is the following problem: the flatness of the exposure area of ​​the substrate cannot be maintained in the hollow square frame, and in particular, the problem of sagging in the center of the substrate cannot be dealt with at all.

[0008] In Patent Document 2, the substrate is clamped by a first clamping portion and a second clamping portion, so that the substrate can be prevented from sagging and exposure can be performed from the back side of the substrate. The first clamping portion and the second clamping portion have a transmissive portion formed by a light-transmitting component and having a flat surface. However, since piping and the like block light, a substrate adsorption mechanism cannot be provided on the light-transmitting component, and therefore the substrate cannot be held by adsorption. Therefore, the warping and undulation of the substrate cannot be completely eliminated by clamping alone, and the flatness cannot be maintained. In addition, due to the local slight thickness error of the light-transmitting component, aberrations will occur on the focusing plane of the exposure optical system. As described above, in the prior art, it is impossible to cope with the focal depth of a high-resolution direct exposure device, and commercialization is difficult. Summary of the invention

[0009] Therefore, the object of the present invention is to provide a direct exposure device and an exposure method for a substrate, which can well maintain the flatness of the exposure area and can simultaneously expose both sides of the substrate for high-resolution pattern exposure even with an exposure optical system with a shallow depth of focus.

[0010] The present invention is a direct exposure device, which comprises:

[0011] a pair of exposure units disposed opposite to each other with the substrate interposed therebetween; and

[0012] A pair of adsorption portions adsorbs the surface of the substrate opposite to the exposure region in the exposure region of each exposure unit.

[0013] According to at least one embodiment of the present invention, since the surface opposite to the exposed surface of the substrate is held by the adsorption portion, both surfaces of the substrate can be exposed while maintaining the flatness of the substrate. In addition, the effects described here are not limited to these, and can be any effect described in the present invention. In addition, the content of the present invention is not limited to the effects illustrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a block diagram of one embodiment of the present invention.

[0015] Figure 2 A, B, and C are a schematic diagram of an exposure head included in an exposure unit according to an embodiment of the present invention, a top view when viewed downward from a first adsorption portion, and Figure 2 AA line section view of B.

[0016] Figure 3 It is a cross-sectional view for explaining the exposure position switching operation according to one embodiment of the present invention.

[0017] Figure 4This is a cross-sectional view for explaining a first step of the suction position switching operation according to one embodiment of the present invention.

[0018] Figure 5 It is a cross-sectional view for explaining the second step of the suction position switching operation according to one embodiment of the present invention.

[0019] Figure 6 It is a cross-sectional view for explaining the third step of the suction position switching operation according to one embodiment of the present invention.

[0020] Figure 7 It is a cross-sectional view for explaining the fourth step of the suction position switching operation according to one embodiment of the present invention.

[0021] Figure 8 A and B are a plan view showing a first surface of a substrate after exposure according to one embodiment of the present invention and a plan view showing a second surface of a substrate after exposure according to one embodiment of the present invention.

[0022] Fig. 9 It is a schematic diagram for explaining a modified example of the present invention.

[0023] Description of symbols

[0024] EU1, EU2: exposure units; H1~H3, H11~H14: exposure heads; W: substrate; 5: first adsorption part; 15: second adsorption part. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the embodiments described below are preferred specific examples of the present invention, and the content of the present invention is not limited to these embodiments.

[0026] Reference Figure 1 The overall structure of one embodiment of the present invention is described. In the direct exposure device, a first exposure unit EU1 and a second exposure unit EU2 are provided to expose the first surface and the second surface opposite to the first surface of the substrate W. The exposure units EU1 and EU2 are arranged opposite to each other with the substrate W interposed therebetween.

[0027] The exposure unit EU1 includes a light source 1 (e.g., LED (light emitting diode), laser diode, ultra-high pressure mercury lamp, xenon lamp, flash lamp, etc.), an illumination optical system (not shown) for adjusting the light emitted from the light source 1, a DMD (digital micromirror device) 2 for modulating the illumination light from the illumination optical system to form pattern light, a projection optical system 3 for projecting the pattern light onto the substrate W, and a focus adjustment unit (wedge prism, etc.) 4 for adjusting the focus position of the projection optical system 3. The exposure unit EU2, like EU1, includes a light source 11, a DMD 12, a projection optical system 13, and a focus adjustment unit 14.

[0028] In the direct exposure device of the present embodiment, an exposure stage ST for holding a substrate W is provided. A first adsorption unit 5 for adsorbing a first surface of the substrate W and a second adsorption unit 15 for adsorbing a second surface of the substrate W are provided on the exposure stage ST. During adsorption, the substrate W is adsorbed or separated (released) from the substrate by vacuum adsorption, electrostatic adsorption, etc. As described later, the first adsorption unit 5 and the second adsorption unit 15 have one or more strip-shaped openings and an exposure region holding unit adjacent to the openings and having a flat adsorption surface.

[0029] The light sources 1 and 11 are supplied with electric power from the light source driving units 6 and 16. The DMDs 2 and 12 are supplied with control signals from the screen generating units 7 and 17, and the DMDs 2 and 12 display predetermined patterns corresponding to the control signals.

[0030] In the direct exposure apparatus, a substrate moving unit 8 is provided to move the substrate W. The substrate moving unit 8 is composed of a linear actuator (not shown), and moves the exposure stage ST in the main scanning direction (+ / -X).

[0031] The exposure position switching unit 9 is composed of a linear actuator (not shown) to independently move the first adsorption unit 5 and the second adsorption unit 15 in the sub-scanning direction (+ / -Y). In addition, the first adsorption unit 5 and the second adsorption unit 15 independently move in the direction of approaching / leaving the substrate W (+ / -Z).

[0032] The direct exposure device is provided with a controller 20 for controlling the entire exposure device. A memory 21 is provided in association with the controller 20. The controller 20 controls the light source driving unit 6, 16, the image generating unit 7, 17, the substrate moving unit 8, and the exposure position switching unit 9 based on the recipe data, exposure pattern data, etc. retrieved from the memory 21. In addition, CAD (computer aided design) / CAM (computer aided manufacturing) data or recipe data, etc., are received from the outside of the exposure device and stored in the memory 21.

[0033] Figure 2 A, B, and C are schematic diagrams of exposure heads included in exposure units EU1 and EU2 according to an embodiment of the present invention, a top view when viewed downward from the first adsorption unit 5, and Figure 2 B is a cross-sectional view taken along line AA. In order to expose the first surface (e.g., the top) of the substrate W, the exposure unit EU1 includes, for example, three exposure heads H1, H2, and H3. In order to expose the second surface (e.g., the bottom) of the substrate W, the exposure unit EU2 includes four exposure heads H11, H12, H13, and H14. Each exposure head is provided with a DMD2, 12. Figure 2 In A, the gray area shows the exposure ranges EA1, EA2, and EA3 of the exposure heads H1, H2, and H3. The exposure ranges EA1, EA2, and EA3 of the exposure heads are arranged at predetermined intervals in the Y direction. In addition, the exposure ranges are not necessarily arranged in a straight line, and may be staggered in the X direction, for example. In addition, although not shown, the same exposure areas also exist in the exposure heads H11, H12, H13, and H14. The number of exposure heads is an example, and the number of exposure heads included in each exposure unit may be 3 or a number other than 3.

[0034] exist Figure 2 In B, the first adsorption part 5 that adsorbs the first surface of the substrate W is formed as a whole with three strip-shaped openings 31a, 31b, and 31c (referred to as the openings 31 for short when there is no need to distinguish them) extending in parallel along the scanning direction on the metal rectangular plate, and the exposure light from the exposure heads H1, H2, and H3 passes through the openings 31 to expose the first surface of the substrate W. Figure 2 In C, L1, L2, and L3 represent exposure lights emitted from the respective exposure heads.

[0035] The first adsorption unit 5 has four parallel prism-shaped exposure region holding parts in the area where the opening 31 is not formed on the surface facing the substrate W, and the substrate W is adsorbed or separated from the substrate W through the band-shaped adsorption area (indicated by the oblique line area) formed in the part of the exposure region holding part that contacts the substrate. The band-shaped adsorption area is formed by a plurality of fine vents (for example, a porous body) and has the function of adsorbing the substrate W while maintaining the surface accuracy. In addition, it does not mean that the substrate W is adsorbed only by the band-shaped adsorption area, and other parts of the first adsorption unit 5 can also cooperate with the band-shaped adsorption area to adsorb the substrate W.

[0036] like Figure 2 As shown in C, the second adsorption part 15 for adsorbing the second surface of the substrate W is also formed in the same shape as the first adsorption part 5. That is, three openings in the shape of strips extending in the scanning direction are formed on the rectangular metal plate. The exposure light from the exposure heads H11, H12, H13, and H14 passes through the openings to expose the second surface of the substrate W. Figure 2 In C, L11, L12, L13, and L14 represent exposure lights emitted from the respective exposure heads. In addition, four prism-shaped exposure region holding portions are provided in parallel in the region where no opening is formed on the surface opposite to the substrate W, and the substrate W is adsorbed or separated from the substrate W by the exposure region holding portions.

[0037] The opening width of each opening of the first adsorption unit 5 and the second adsorption unit 15 is equal to or slightly larger than the width of the exposure range of the exposure head. In addition, the width of each exposure area holding portion of the first adsorption unit 5 and the second adsorption unit 15 is determined by the pitch of the exposure heads, but is set to be approximately equal to the width of the exposure area.

[0038] like Figure 2 As shown in FIG. 3 , when the substrate W is adsorbed by the first adsorption unit 5 and the second adsorption unit 15, the exposure area of ​​the first surface corresponding to the opening 31 is exposed by the exposure lights L1 to L3 of the exposure heads H1 to H3, and the exposure area of ​​the second surface corresponding to the opening of the second adsorption unit is exposed by the exposure lights L11 to L13 of the exposure heads H11 to H13. In addition, since the exposure head H14 is located outside the predetermined exposure range of the substrate W, Figure 2 The exposure light is not projected in C. The exposure areas of the exposure heads H1 to H3 and the exposure areas of the exposure heads H11 to H14 are staggered in the sub-scanning direction (Y). In other words, when viewed from the main scanning direction (X), the exposure areas of the exposure heads H1 to H3 and the exposure areas of the exposure heads H11 to H14 are arranged in different positions from each other in the sub-scanning direction (Y). Since the substrate W is clamped by the multiple exposure area holding parts of the first adsorption part 5 and the multiple exposure area holding parts of the second adsorption part 15 during exposure, the flatness of the substrate W can be well maintained.

[0039] In one embodiment of the present invention, the exposure unit is fixed, and the exposure stage ST (substrate W) is moved along the main scanning direction (X) by the substrate moving part 8 as the first moving part, but the substrate W may be fixed and the exposure unit may be moved. In the present invention, a second moving part is provided to relatively move the substrate W and the exposure area in the sub-scanning direction (+ / -Y). In addition, in the present invention, a third moving part is provided to move the substrate adsorption position of a pair of adsorption parts (exposure stage ST) in the sub-scanning direction (+ / -Y). In one embodiment, the first adsorption part 5 and the second adsorption part 15 are independently moved in the sub-scanning direction (+ / -Y) by the exposure position switching part 9. In addition, the second moving part may be provided on the exposure unit side to move the exposure unit relative to the substrate.

[0040] The exposure action of one embodiment of the present invention is described in sequence below. The direct exposure device exposes a pattern on the substrate by a known method. In one embodiment, while the exposure unit and the substrate are relatively moved in the main scanning direction (X), the light modulation element array (DMD) of the exposure unit is modulated by the screen generation unit according to the relative movement amount, thereby directly exposing the pattern to a band-shaped range extending in the main scanning direction with a width corresponding to the exposure area by a multiple exposure method. In the present invention, the entire surface of the substrate W is exposed by performing multiple exposures. This exposure method is called multiple exposure. In one embodiment, the entire surface of the substrate is exposed by two exposures. This method is called two-time exposure. However, two-time exposure is only an example, and the entire surface of the substrate can also be exposed by three or more exposures. In this case, the number of exposure heads can be reduced compared to the case of two exposures.

[0041] like Figure 2 As shown in C, when the exposure (first exposure) is completed, the exposure position switching operation is performed. That is, the first adsorption portion 5 and the second adsorption portion 15 (that is, the entire exposure stage ST) are moved in the +Y direction by a spacing while maintaining the adsorption state, becoming Figure 3 For example, the width of the exposure region holding portion of each of the first adsorption unit 5 and the second adsorption unit 15 is set equal to the width of the exposure region (width of the opening), and the equal width is set to one pitch.

[0042] Next, the first step of the adsorption position switching operation is performed. In this first step, the first adsorption part 5 is released from adsorption, moves in the +Z direction (upward), and moves 1 pitch in the -Y direction. The resulting state is as follows: Figure 4 shown.

[0043] Next, the second step of the suction position switching operation is performed. In the second step, the first suction portion 5 moves in the -Z direction (downward) to contact the substrate W and suction the substrate W. The resulting state is as follows: Figure 5 shown.

[0044] Next, the third step of the adsorption position switching operation is performed. In the third step, the second adsorption portion 15 is released from adsorption, moves in the -Z direction (downward), and moves in the +Y direction by one pitch. The resulting state is as follows: Figure 6 shown.

[0045] Next, the fourth step of the suction position switching operation is performed. In the fourth step, the second suction portion 15 moves in the +Z direction (upward) to contact the substrate W and suction the substrate W. Then, as shown in FIG. Figure 7 As shown, the remaining area of ​​the first surface is exposed by the exposure lights L1, L2, and L3 from the exposure heads H1, H2, and H3, and the remaining area of ​​the second surface is exposed by the exposure lights L12, L13, and L14 from the exposure heads H12, H13, and H14. In addition, since the exposure head H11 is located outside the exposure range of the substrate W, Figure 7 There is no projected exposure light.

[0046] The result of the above processing is that Figure 8 As shown in A, the first surface (top) of the substrate W is exposed. Figure 8 As shown in FIG. 1B , the second side (lower side) of the substrate W is exposed. Figure 8 A and Figure 8 In B, the area marked with I is the area exposed by the first exposure, and the area marked with II is the area exposed by the second exposure.

[0047] According to the present invention, a direct exposure device can be provided, which has a pair of adsorption parts for adsorbing opposite sides of an exposure area, and can well maintain the flatness of the exposure area. Even with an exposure optical system with a shallow depth of focus, it is possible to simultaneously expose both sides of a substrate that can perform high-resolution pattern exposure.

[0048] Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above embodiments, and various modifications can be made based on the technical concept of the present invention. For example, the exposure unit (exposure head) may be moved to switch the exposure position.

[0049] Fig. 9This is a modified example of the present invention. The substrate adsorption units 51 and 52 do not have a moving mechanism, but are fixed to the exposure units EU1 and EU2 (or the base unit), and the substrate W is exposed while being moved in the scanning direction by the substrate transport mechanism 53. At this time, while the substrate adsorption units 51 and 52 adsorb the substrate W, a small amount of air is blown locally, so that the substrate W is slid while being adsorbed. In a two-sided simultaneous direct exposure device with such a structure, by using the substrate adsorption unit to adsorb the opposite side of the substrate in the exposure area of ​​each exposure unit, the flatness of the exposure area can also be well maintained.

[0050] In addition, the present invention is not limited to panel-shaped substrates, and can also be applied to long strip substrates (film-shaped substrates). Furthermore, exposure can be performed by stepping while the adsorption unit is intermittently turned on and off. Alternatively, scanning exposure can be performed by spraying compressed gas while the adsorption unit is adsorbing to reduce the friction of the substrate.

[0051] For example, the structures, methods, processes, shapes, materials, and numerical values ​​listed in the above embodiments are merely examples, and different structures, methods, processes, shapes, materials, and numerical values ​​may be used as needed.

[0052] In addition, the structures, methods, processes, shapes, materials, and numerical values ​​of the above-mentioned embodiments can be combined with each other as long as they do not depart from the gist of the present invention. In addition, the present invention is not limited to devices, systems, etc., and can be implemented in any form.

Claims

1. A direct exposure device, comprising: a pair of exposure units, which are opposed to each other with the substrate interposed therebetween and are respectively arranged on both sides of the substrate; and a pair of adsorption parts, which are opposite to each other with the substrate interposed therebetween and are respectively arranged on both sides of the substrate, The adsorption parts respectively include: a plurality of exposure region holding parts having flat adsorption surfaces for adsorbing and holding the surface of the substrate opposite to the exposure region; and a plurality of strip-shaped openings adjacent to the exposure region holding parts and for allowing exposure light to pass through. The exposure area of ​​one exposure unit of the pair of exposure units is arranged in a manner offset from the exposure area of ​​the other exposure unit in the sub-scanning direction (Y). The exposure unit performs exposure in a state where the exposure region holding portion on one side of the substrate and the exposure region holding portion on the other side of the substrate adsorb the substrate.

2. The direct exposure device according to claim 1, wherein: Each of the exposure units has a plurality of exposure regions arranged at intervals in the sub scanning direction (Y), and the plurality of exposure regions of the one exposure unit and the plurality of exposure regions of the other exposure unit are arranged so as to be located at different positions from each other.

3. The direct exposure apparatus according to claim 1, wherein: The direct exposure device includes a first moving unit that moves the pair of adsorption units in a scanning direction (X) so that the substrate is relatively moved with respect to the exposure region in the scanning direction (X) to perform exposure.

4. The direct exposure apparatus according to claim 3, wherein: The direct exposure device includes a second moving part and a third moving part. The second moving part moves the substrate and the exposure area relative to each other in the sub-scanning direction (Y). The third moving part moves the substrate adsorption position of the adsorption part in the sub-scanning direction (Y).

5. The direct exposure apparatus according to claim 4, wherein: When the substrate suction position is moved, a state in which at least a portion of the substrate is suctioned is maintained.

6. A method for exposing a substrate, the method utilizing a direct exposure device, the direct exposure device comprising: a pair of exposure units, which are opposed to each other with the substrate interposed therebetween and are respectively arranged on both sides of the substrate; as well as A pair of adsorption parts are opposed to each other with the substrate interposed therebetween and are respectively arranged on both sides of the substrate, the adsorption parts respectively comprising: a plurality of exposure area holding parts having flat adsorption surfaces for adsorbing and holding the surfaces of the substrate opposite to the exposure area; and a plurality of strip-shaped openings adjacent to the exposure area holding parts and for allowing exposure light to pass through, the exposure area of ​​one exposure unit in the pair of exposure units being arranged in a staggered manner with the exposure area of ​​the other exposure unit in a sub-scanning direction (Y), and the exposure method of the substrate comprising the following steps: The pair of exposure units and the substrate adsorbed on the adsorption portion are relatively moved in a main scanning direction (X) to expose a portion of both surfaces of the substrate; causing the substrate and the pair of exposure units to move relative to each other in a sub-scanning direction (Y); Moving the position of the adsorption portion adsorbing the substrate in the secondary scanning direction (Y); and The pair of exposure units and the substrate adsorbed on the adsorption portion are relatively moved in the main scanning direction (X) to expose other portions of the two surfaces of the substrate. The exposure unit performs exposure in a state where the exposure region holding portion on one side of the substrate and the exposure region holding portion on the other side of the substrate adsorb the substrate.

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