阅读说明：本技术 直接曝光装置和基板的曝光方法 (Direct exposure apparatus and method for exposing substrate ) 是由 绿川悟 于 2020-11-18 设计创作，主要内容包括：本发明提供一种直接曝光装置和基板的曝光方法。能够良好地保持曝光区域的平面度,即使是焦点深度浅的曝光光学系统,也能够对可进行高分辨率的图案曝光的基板的两个面同时进行曝光。直接曝光装置具有：一对曝光单元,它们隔着基板对置配置；以及一对吸附部,它们在各曝光单元的曝光区域中吸附所述基板的与所述曝光区域相反的面。(The invention provides a direct exposure apparatus and an exposure method of a substrate. The flatness of an exposure area can be well maintained, and even if the exposure optical system is a shallow focal depth exposure optical system, the exposure optical system can simultaneously expose two surfaces of a substrate capable of carrying out high-resolution pattern exposure. The direct exposure apparatus includes: a pair of exposure units arranged opposite to each other with a substrate interposed therebetween; and a pair of suction portions that suction a surface of the substrate opposite to an exposure region of each exposure unit.)

1. A direct exposure apparatus includes:

a pair of exposure units arranged opposite to each other with a substrate interposed therebetween; and

and a pair of suction portions that suck the surface of the substrate opposite to the exposure region in the exposure region of each exposure unit.

2. The direct exposure apparatus according to claim 1,

an exposure region of one exposure unit and an exposure region of the other exposure unit of the pair of exposure units are arranged so as to be shifted in the sub-scanning direction (Y).

3. The direct exposure apparatus according to claim 2,

each of the exposure units has a plurality of exposure regions arranged in the sub-scanning direction (Y) at intervals, 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 positions different from each other.

4. The direct exposure apparatus according to any one of claims 1 to 3,

the pair of suction portions are arranged on an exposure stage on which the substrate is placed,

the pair of suction portions are disposed to face each other with the substrate interposed therebetween,

the adsorption parts are respectively provided with: a plurality of exposure region holding portions for holding the opposite surfaces of the exposure regions of the exposure units by suction; and a plurality of strip-shaped openings adjacent to the exposure region holding portion and through which exposure light passes.

5. The direct exposure apparatus according to claim 4,

the direct exposure apparatus includes a first moving unit that moves the exposure stage in a scanning direction (X) to move the substrate relative to the exposure area in the scanning direction (X) to perform exposure.

6. The direct exposure apparatus according to claim 5,

the direct exposure apparatus includes a second moving unit that relatively moves the substrate and the exposure region in a sub-scanning direction (Y), and a third moving unit that moves a substrate suction position of the suction unit in the sub-scanning direction (Y).

7. The direct exposure apparatus according to claim 6,

when the substrate adsorption position is moved, at least a part of the substrate is maintained in the state of being adsorbed.

8. A method of exposing a substrate using a direct exposure apparatus for exposing both surfaces of the substrate by moving the substrate between a pair of exposure units arranged to face each other, the method comprising:

exposing a part of both surfaces of the substrate by relatively moving the pair of exposure units and the substrate adsorbed on the adsorption part in a main scanning direction (X);

relatively moving the substrate and the pair of exposure units in a sub-scanning direction (Y);

moving a position of the suction part that sucks the substrate in a sub-scanning direction (Y); and

the pair of exposure units and the substrate adsorbed on the adsorption part are relatively moved in a main scanning direction (X), and other parts of two surfaces of the substrate are exposed.

Technical Field

The present invention relates to a direct exposure apparatus and a substrate exposure method for drawing a predetermined pattern on a front surface and a back surface of a substrate.

Background

In a photolithography process for manufacturing substrates such as printed wiring boards, semiconductor wafers, LCD glass substrates, LED substrates, and organic EL substrates, a direct exposure apparatus (maskless exposure apparatus) is known which 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 is possible.

Further, when both the front and back surfaces of the substrate need to be drawn, one surface is drawn first, and then the substrate is inverted and the other surface is drawn. In particular, in a printed wiring board, circuit patterns are generally formed on both surfaces of a substrate. However, when drawing is performed on both the front and back surfaces of the substrate, a step of inverting the substrate is required, and therefore, the processing efficiency cannot be improved. In addition, the accuracy of positioning the front and back surfaces of the substrate may be lowered.

Therefore, there is an increasing demand for a direct exposure apparatus to expose both sides of a substrate simultaneously. For example, patent document 1 describes an apparatus in which an object to be drawn (substrate) is held by an upper holding frame and a lower holding frame, and both surfaces are irradiated with laser beams through glass of a through hole to perform exposure. Patent document 2 describes that both-side exposure is performed in a state where the substrate is held between the upper and lower holding portions.

Patent document 1: japanese laid-open patent publication No. 2009-122597

Patent document 2: japanese patent laid-open publication No. 2014-19 190987

The direct exposure apparatus tends to make the depth of focus of the exposure optical system shallower as the resolution of the pattern to be exposed becomes higher. Therefore, the difference in height (flatness) of the exposed area is required to be within several μm. In the apparatus described in patent document 1, since the substrate is held by the hollow square frame-shaped holding frame, exposure can be performed not only from the front surface of the substrate but also from the back surface of the substrate. However, there are the following problems: the flatness of the exposure area of the substrate cannot be maintained in the hollow square frame, and particularly, the problem of sagging of the central portion of the substrate cannot be solved at all.

In patent document 2, the substrate is held between a first holding portion and a second holding portion having a transparent portion formed of a translucent member and having a flat surface, so that the substrate can be exposed from the back surface side while preventing sagging. However, since the piping or the like blocks light, the substrate cannot be held by suction because the substrate suction mechanism cannot be provided on the translucent member. Therefore, warpage and undulation of the substrate cannot be completely eliminated only by clamping, and flatness cannot be maintained. Further, due to a local minute thickness error of the light-transmissive member, aberration occurs on the focal plane of the exposure optical system. As described above, the conventional techniques cannot cope with the depth of focus of a direct exposure apparatus with high resolution, and thus, the production of products is difficult.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a direct exposure apparatus and a substrate exposure method, which can simultaneously expose both surfaces of a substrate capable of performing pattern exposure with high resolution even in an exposure optical system with a shallow depth of focus while maintaining flatness of an exposure region.

The present invention is a direct exposure apparatus including:

a pair of exposure units arranged opposite to each other with a substrate interposed therebetween; and

and a pair of suction portions that suck the surface of the substrate opposite to the exposure region in the exposure region of each exposure unit.

According to at least one embodiment of the present invention, since the surface opposite to the exposed surface of the substrate is sucked and held by the suction portion, both surfaces of the substrate can be exposed while maintaining the flatness of the substrate well. The effect described here is not limited to this, and may be any effect described in the present invention. The contents of the present invention are not to be interpreted as being limited to the effects illustrated.

Drawings

FIG. 1 is a block diagram of one embodiment of the present invention.

A, B, C in FIG. 2 is a schematic diagram of an exposure head included in the exposure unit according to the embodiment of the present invention, a plan view as viewed from below of the first suction portion, and a sectional view taken along line A-A in FIG. 2B.

Fig. 3 is a sectional view for explaining an exposure position switching operation according to an embodiment of the present invention.

Fig. 4 is a cross-sectional view for explaining a first step of the suction position switching operation according to the embodiment of the present invention.

Fig. 5 is a cross-sectional view for explaining a second step of the suction position switching operation according to the embodiment of the present invention.

Fig. 6 is a cross-sectional view for explaining a third step of the suction position switching operation according to the embodiment of the present invention.

Fig. 7 is a cross-sectional view for explaining a fourth step of the suction position switching operation according to the embodiment of the present invention.

A, B in FIG. 8 is a plan view showing the first surface of the substrate exposed by the embodiment of the present invention and a plan view showing the second surface of the substrate exposed by the embodiment of the present invention.

Fig. 9 is a schematic diagram for explaining a modification of the present invention.

Description of the reference symbols

EU1, EU 2: an exposure unit; H1-H3, H11-H14: an exposure head; w: a substrate; 5: a first adsorption part; 15: a second adsorption part.

Detailed Description

Hereinafter, embodiments and the like of the present invention will be described with reference to the drawings. The embodiments and the like described below are preferable specific examples of the present invention, and the contents of the present invention are not limited to these embodiments and the like.

The overall structure of an embodiment of the present invention will be described with reference to fig. 1. In the direct exposure apparatus, a first exposure unit EU1 and a second exposure unit EU2 are provided to expose a first surface and a second surface, which is a surface opposite to the first surface, of a substrate W. The exposure units EU1 and EU2 are arranged to face each other with the substrate W interposed therebetween.

The exposure unit EU1 includes a light source 1 (e.g., an LED (light emitting diode), a laser diode, an ultra-high pressure mercury lamp, a xenon lamp, a flash lamp, etc.), an illumination optical system (not shown) for adjusting 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 (e.g., a wedge prism) 4 for adjusting the focus position of the projection optical system 3. The exposure unit EU2 includes a light source 11, a DMD12, a projection optical system 13, and a focus adjustment unit 14, similarly to EU 1.

In the direct exposure apparatus of the present embodiment, an exposure stage ST for holding a substrate W is provided. The exposure stage ST is provided with a first suction unit 5 that sucks the first surface of the substrate W and a second suction unit 15 that sucks the second surface of the substrate W. In the adsorption, the substrate W is adsorbed or separated (desorbed) by vacuum adsorption, electrostatic adsorption, or the like. As described later, the first suction portion 5 and the second suction portion 15 have 1 or more strip-shaped openings and an exposure area holding portion adjacent to the openings and having a flat suction surface.

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

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

The exposure position switching section 9 is constituted by a linear actuator, not shown, and moves the first suction section 5 and the second suction section 15 in the sub-scanning direction (+/-Y) independently of each other. In addition, the first suction part 5 and the second suction part 15 are moved in the direction (+/-Z) to approach and separate from the substrate W, respectively and independently.

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

A, B, C in FIG. 2 is a schematic diagram of exposure heads included in the exposure units EU1 and EU2 in the embodiment of the present invention, a plan view as viewed from below of the first adsorption part 5, and a sectional view taken along line A-A in FIG. 2B. For example, three exposure heads H1, H2, and H3 are included in the exposure unit EU1 for exposing a first surface (e.g., upper surface) of the substrate W, and 4 exposure heads H11, H12, H13, and H14 are included in the exposure unit EU2 for exposing a second surface (e.g., lower surface) of the substrate W. Each exposure head is provided with a DMD2, 12. In a of fig. 2, the gray-colored regions show exposure ranges EA1, EA2, EA3 of the exposure heads H1, H2, H3. Exposure ranges EA1, EA2, and EA3 of the exposure head are arranged at predetermined intervals in the Y direction. The exposure ranges are not necessarily arranged along a straight line, and may be staggered in the X direction, for example. Although not shown, exposure heads H11, H12, H13, and H14 have the same exposure region. The number of exposure heads is an example, and the number of exposure heads included in each exposure unit may be 3 or may be other than 3.

In fig. 2B, the first suction portion 5 sucking the first surface of the substrate W is formed with 3 strip-shaped openings 31a, 31B, and 31c (simply referred to as openings 31 when it is not necessary to distinguish them) extending in the scanning direction in parallel on a rectangular plate of metal as a whole, and the first surface of the substrate W is exposed through the openings 31 by the exposure light from the exposure heads H1, H2, and H3. In fig. 2C, L1, L2, and L3 denote exposure light beams emitted from the respective exposure heads.

The first suction portion 5 has four parallel exposure region holding portions in a prism shape in a region where the opening 31 is not formed on the surface facing the substrate W, and sucks or separates the substrate W from the substrate W by a band-shaped suction region (indicated by a hatched region) formed in a portion of the exposure region holding portion that is in contact with the substrate. The belt-like suction region is formed of a plurality of fine air holes (for example, porous bodies), and has a function of sucking the substrate W while maintaining surface accuracy. It is not intended that the substrate W be sucked only by the band-shaped suction regions, and the other portions of the first suction parts 5 may suck the substrate W in cooperation with the band-shaped suction regions.

As shown in C of fig. 2, the second suction portion 15 for sucking the second surface of the substrate W is also formed in the same shape as the first suction portion 5. That is, three strip-shaped openings extending in the scanning direction are formed in a rectangular metal plate. The exposure light from the exposure heads H11, H12, H13, and H14 passes through the opening to expose the second surface of the substrate W. In fig. 2C, L11, L12, L13, and L14 represent exposure light emitted from each exposure head. In addition, four exposure region holding portions each having a prism shape are provided in parallel to a region where no opening is formed on a surface facing the substrate W, and the substrate W is attracted to or separated from the substrate W by the exposure region holding portions.

The opening width of each opening of the first adsorption part 5 and the second adsorption part 15 is equal to or slightly larger than the width of the exposure range of the exposure head. The width of the exposure region holding portion of each of the first suction portion 5 and the second suction portion 15 is defined by the pitch of the exposure head, but is set to be substantially equal to the width of the exposure region.

As shown in C of fig. 2, in a state where the substrate W is adsorbed by the first and second adsorption portions 5 and 15, the exposure region of the first surface corresponding to the opening 31 is exposed to the exposure lights L1 to L3 of the exposure heads H1 to H3, and the exposure region of the second surface corresponding to the opening of the second adsorption portion is exposed to 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 range for exposure of the substrate W, exposure light is not projected in C of fig. 2. The exposure regions of the exposure heads H1 to H3 and the exposure regions of the exposure heads H11 to H14 are arranged in a staggered manner in the sub-scanning direction (Y). In other words, the exposure regions of the exposure heads H1 to H3 and the exposure regions of the exposure heads H11 to H14 are arranged so as to be located at positions different from each other in the sub-scanning direction (Y) when viewed from the main scanning direction (X). Since the substrate W is sandwiched between the plurality of exposure field holding portions of the first suction portion 5 and the plurality of exposure field holding portions of the second suction portion 15 during exposure, the flatness of the substrate W can be maintained well.

In one embodiment of the present invention, the exposure unit is fixed, and the exposure stage ST (substrate W) is moved in the main scanning direction (X) by the substrate moving unit 8 as the first moving unit. In the present invention, a second moving portion is provided for relatively moving the substrate W and the exposure region in the sub-scanning direction (+/-Y). In the present invention, a third moving unit is provided for moving the substrate suction position of the pair of suction units (exposure stage ST) in the sub-scanning direction (+/-Y). In one embodiment, the first suction portions 5 and the second suction portions 15 are independently moved in the sub-scanning direction (+/-Y) by the exposure position switching portion 9. Further, the second moving unit may be provided on the exposure unit side to move the exposure unit relative to the substrate.

Hereinafter, the exposure operation according to one embodiment of the present invention will be described in order. The direct exposure apparatus exposes a pattern on a substrate by a known method. In one embodiment, a pattern is directly exposed by a multiple exposure method to a band-like range extending in the main scanning direction with a width corresponding to an exposure area by modulating a light modulation element array (DMD) of an exposure unit by a screen generation unit according to a relative movement amount while relatively moving the exposure unit and a substrate in the main scanning direction (X). In the present invention, the entire surface of the substrate W is exposed by performing exposure a plurality of times. This exposure method is referred to as multiple exposure. In one embodiment, the entire surface of the substrate is exposed by 2 exposures. This mode is referred to as 2 exposures. However, 2 exposures are only an example, and 3 exposures or 3 or more exposures may be used to expose the entire surface of the substrate. In this case, the number of exposure heads can be reduced as compared with the case of 2 exposures.

As shown in C of fig. 2, when the exposure (first exposure) is completed, the exposure position switching operation is performed. That is, when the suction state is maintained, the first suction unit 5 and the second suction unit 15 (i.e., the entire exposure stage ST) are moved by one pitch in the + Y direction, and the state shown in fig. 3 is obtained. For example, the width of the exposure region holding portion and the width of the exposure region (the width of the opening) of each of the first adsorption part 5 and the second adsorption part 15 are set to be equal, and the equal widths are set to have one pitch.

Next, a first step of switching the suction position is performed. In the first step, the first adsorption part 5 releases the adsorption, moves in the + Z direction (upward), and moves in the-Y direction by 1 pitch. The resulting state is shown in fig. 4.

Next, a second step of performing a suction position switching operation. In the second step, the first suction unit 5 moves in the-Z direction (downward), and contacts the substrate W to suck the substrate W. The resulting state is shown in fig. 5.

Next, a third step of performing a suction position switching operation. In the third step, the second suction unit 15 releases the suction, moves in the-Z direction (downward), and moves in the + Y direction by one pitch. The resulting state is shown in fig. 6.

Next, a fourth step of performing a suction position switching operation. In the fourth step, the second suction unit 15 moves in the + Z direction (upward), and contacts the substrate W to suck the substrate W. Then, as shown in fig. 7, the remaining region of the first surface is exposed by exposure light L1, L2, and L3 from exposure heads H1, H2, and H3, and the remaining region of the second surface is exposed by exposure light L12, L13, and L14 from exposure heads H12, H13, and H14. In addition, since the exposure head H11 is located outside the predetermined range for exposure of the substrate W, exposure light is not projected in fig. 7.

As a result of the above processing, the first surface (upper surface) of the substrate W is exposed as shown in a of fig. 8, and the second surface (lower surface) of the substrate W is exposed as shown in B of fig. 8. In fig. 8 a and 8B, the region marked I is a region exposed by the first exposure, and the region marked II is a region exposed by the second exposure.

According to the present invention, it is possible to provide a direct exposure apparatus including a pair of suction portions that suck opposite surfaces of an exposure region, which can maintain flatness of the exposure region in a satisfactory manner, and which can simultaneously expose both surfaces of a substrate that can be subjected to pattern exposure with high resolution even in an exposure optical system with a shallow depth of focus.

While 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 idea of the present invention. For example, the exposure unit (exposure head) may be moved to switch the exposure position.

Fig. 9 shows a modification of the present invention. The substrate suction units 51 and 52 are fixed to the exposure units EU1 and EU2 (or base unit) without a moving mechanism, and perform exposure while moving the substrate W in the scanning direction by the substrate transport mechanism 53. At this time, the substrate W is sucked by the substrate suction portions 51 and 52, and the substrate W is slid while being sucked by locally blowing a small amount of air. In the above-structured two-side simultaneous direct exposure apparatus, the substrate suction unit sucks the opposite side of the substrate in the exposure region of each exposure unit, whereby the flatness of the exposure region can be maintained satisfactorily.

The present invention is not limited to a panel-shaped substrate, and can be applied to a long substrate (film-shaped substrate). Further, the exposure may be performed by intermittently turning on and off the suction unit and simultaneously performing a step movement. Alternatively, the adsorption portion adsorbs the substrate and the compressed gas is simultaneously injected to reduce the friction of the substrate, thereby performing the scanning exposure.

For example, the structures, methods, steps, shapes, materials, numerical values, and the like recited in the above embodiments are merely examples, and different structures, methods, steps, shapes, materials, numerical values, and the like may be used as necessary.

The structures, methods, steps, shapes, materials, numerical values, and the like of the above embodiments may be combined with each other without departing from the spirit of the present invention. Further, the present invention is not limited to the device, system, and the like, and may be implemented in any manner.