JP6953757B2 - Light irradiation device - Google Patents

Description

The present invention relates to a light irradiation device using a plurality of LEDs.

In the fields of semiconductor and liquid crystal exposure and other microfabrication fields, exposure technology using an ultraviolet lamp such as a metal halide lamp is used as a light source for photolithography.
However, ultraviolet lamps such as metal halide lamps have the disadvantage that it is difficult to turn them on again immediately after they are turned off, resulting in a large energy loss. In addition, there is a problem that the object to be irradiated is undesirably heated by the heat rays generated together with the ultraviolet rays.
In recent years, an exposure apparatus equipped with a light irradiation apparatus using an LED as an alternative light source for an ultraviolet lamp has been actively developed.

Therefore, when an LED is used as a light source instead of an ultraviolet lamp, there are mainly the following two problems.
First, the ultraviolet lamp can obtain a high amount of light from the bright spot of the arc formed between the electrodes, but the LED has a small amount of light emission per chip. Therefore, in order to use it as a light source for an exposure apparatus, a light source unit equipped with a large number of LEDs is required. However, the light radiation output of each LED tends to vary due to individual differences of LEDs, the influence of heat distribution, and the like. Furthermore, it is conceivable that some LEDs will not light up. For this reason, it is difficult to make the illuminance on the light irradiation surface uniform in a light irradiation device provided with a light source unit equipped with a large number of LEDs.

Secondly, in the light source unit in which a plurality of LEDs are arranged on the same plane, when the light from each LED is emitted to the light irradiation surface, there is a problem that the viewing angle with respect to the light irradiation surface tends to widen. .. When the viewing angle becomes large, it becomes a factor that the processing accuracy of the light treatment for the object to be irradiated deteriorates. In particular, as shown in FIG. 8, the bias of light absorption in the thickness direction (depth direction) of the object to be irradiated becomes large. In FIG. 8, the vertical direction indicates the thickness direction of the object to be irradiated, and the horizontal direction indicates the position of the object to be irradiated in the surface direction. In addition, La indicates a light absorption region.
As shown in FIG. 9, the “viewing angle” here indicates the spread width of the effective incident angle of light from an arbitrary position on the light irradiation surface LS, and is the angle α in FIG. In the present specification, the effective viewing angle is determined from the half width at half maximum when the incident angle intensity distribution (relative intensity distribution of light per incident angle) of the light beam incident on the light irradiation surface LS is taken. In FIG. 9, 30 is a light source unit and 31 is an LED.

For example, Patent Document 1 describes that the following measures are taken for the above two problems. FIG. 10A is a schematic diagram showing an outline of a configuration in an example of a conventional light irradiation device using an LED.
First, for the first problem, the distance between the light source unit 30 in which a plurality of LEDs 31 are arranged on the same plane and the object to be irradiated W (actually, the light source unit 30 and the object to be irradiated). It is described that the distance between the objects W and the mask 45 arranged between the objects W, the working distance) WD is increased. As a result, the light emitted from each LED 31 is mixed, so that the variation in the light radiation output of each LED 31 is alleviated (compensated), and the uniformity of illuminance on the light irradiation surface LS can be improved. There is.
Further, with respect to the second problem, as shown in FIG. 10B, it is described that the aperture array 40 is provided at a position close to the light source unit 30. As a result, the opening angle θ of the light emitted from each LED 31 is reduced, and it is said that the spatial resolution of light processing for the object W to be irradiated can be increased.

On the other hand, for example, Patent Document 2 describes that the following measures are taken for the above two problems. FIG. 11 is a schematic diagram showing an outline of a configuration in still another example of a conventional light irradiation device using an LED.
That is, it is described that a plurality of segment light sources 30a composed of a plurality of LEDs 31 and a light guide unit 35 arranged on the same substrate 32 are arranged side by side in the plane direction of the substrate 32 to form the light source unit 30. ing. As a result, the light emitted from each LED 31 is reflected by the inner surface of the light guide unit 35 and mixed, so that the illuminance on the light irradiation surface LS can be made uniform.

JP-A-2002-303988 Japanese Unexamined Patent Publication No. 2011-146746

However, in the light irradiation device described in Patent Document 1, if the opening angle θ is narrowed by using an optical component such as the aperture array 40, the light of each LED 31 becomes difficult to mix (low light mixing property). Therefore, the viewing angle on the light-irradiated surface can be narrowed, but the uniformity of the illuminance on the light-irradiated surface is deteriorated. In this case, in order to ensure the uniformity of the illuminance, it is necessary to make the working distance WD extremely large, which leads to an increase in the size of the device and a low efficiency of light utilization.

On the other hand, in the light irradiation device described in Patent Document 2, the number of LEDs 31 in each segment light source 30a is limited due to the structural reason of reflecting the light of each LED 31 a plurality of times. Therefore, in order to avoid a decrease in illuminance on the light irradiation surface LS, a large number of segment light sources 30a are required.
Furthermore, if there is a variation in illuminance for each segment light source 30a, it is necessary to provide a feedback control unit for each segment light source 30a, and it is difficult to make the illuminance uniform on the light irradiation surface LS (very complicated). ).
Furthermore, in the light irradiation device described in Patent Document 2, the opening angle of the light emitted from the LED 31 is stored in the light guide unit 35. Therefore, the viewing angle on the light irradiation surface LS cannot be narrowed. Further, since the light emitted from the opening of the light guide unit 35 tends to spread before reaching the light irradiation surface LS, the illuminance on the light irradiation surface LS is lowered. In order to prevent a decrease in illuminance on the light irradiation surface LS, it is conceivable to reduce the distance from the opening end of the light guide portion 35 to the object W to be processed from WD1 to WD2 as shown by the alternate long and short dash line in FIG. Be done. However, in such a case, it becomes a restriction on the device design, which is not preferable.

The present invention has been made based on the above circumstances, and in a light irradiation device provided with a plurality of LEDs, the viewing angle on the light irradiation surface can be suppressed to be small and high illuminance uniformity can be achieved. An object of the present invention is to provide a light irradiation device that can be obtained.

In the light irradiation device of the present invention, when three directions orthogonal to each other are the x direction, the y direction, and the z direction, a plurality of LEDs whose optical axes extend in the z direction on the same plane extending in the x direction and the y direction. In a light irradiation device including a light source unit in which lights are arranged side by side in the x direction and the y direction, and a reflection unit that reflects light from the light source unit.
When the axis extending in the z direction including the center position of the LED arrangement region in the light source unit is used as the reference axis, the xz cross section or the yz cross section including the reference axis
The reflective portion has a relationship of 0.008 ≦ A ≦ 0.5 when the ratio of the width (Wa) of the LED arrangement area and the opening width (Wb) of the reflective portion is A (= Wa / Wb). It has a form that spreads outward with respect to the reference axis toward the front in the light emitting direction so as to satisfy the above .
The angle of inclination of the first virtual line connecting the position of the end of the reflection on the light source side and the position of the edge of the opening on the light emitting side of the reflection is θ ₁ , on the reference axis. The inclination angle of the second virtual line connecting the same z-direction level position as the plane on which the light emitting surface of each LED is located and the position of the light emitting side opening edge of the reflecting portion with respect to the reference axis is θ _2. When, it is characterized in that the following relationships (1) and (2) are satisfied.
(1) 15 ° ≤ θ ₁ ≤ 37.4 °
(2) 24.8 ° ≤ θ ₂ ≤ 41.2 °, θ ₁ <θ ₂

In the light irradiation device of the present invention, it is preferable that the plurality of LEDs constituting the light source unit are made of a plurality of types having different central emission wavelengths.
Furthermore, in the light irradiation device of the present invention, it is preferable that the reflecting portion has a light diffusing reflecting surface.
In such a configuration, the diffusive reflective surface of the reflective portion is preferably composed of a large number of flat surfaces, and more preferably composed of dimples formed on the inner surface of the reflective portion. ..
Furthermore, in the light irradiation device of the present invention, it is preferable that the reflecting portion has a polygonal opening shape at the light emitting side opening end.

In the light irradiation device of the present invention, the width of the LED arrangement area is sufficiently smaller than the opening width of the reflection portion, and the light source portion has a configuration in which a plurality of LEDs are densely arranged. Moreover, since the reflecting portion has a specific form, the emission angle of the light directly emitted from the LED through the opening of the reflecting portion and the emission angle of the reflected light reflected and emitted by the reflecting portion. Is regulated. Therefore, according to the light irradiation device of the present invention, the viewing angle on the light irradiation surface can be suppressed to be small, and the light mixing property of the light from each LED is increased to improve the uniformity of the illuminance on the light irradiation surface. Can be high.

It is a perspective view which shows the outline of the structure in the example of the light irradiation apparatus of this invention. FIG. 3 is a cross-sectional view taken along a plane extending in the x-direction and the z-direction in the light irradiation device shown in FIG. 1A. It is a top view which shows the outline of the structure in an example of a light source part. FIG. 5 is a cross-sectional view taken along a plane extending in the x-direction and the z-direction, which outlines the configuration of a reflecting portion in the light irradiation device shown in FIG. 1A. It is a figure which shows the light absorption distribution in the thickness direction (depth direction) of the object to be irradiated when the viewing angle on the light irradiation surface is small. It is a figure which shows typically the structure in the example of the contact exposure apparatus to which the light irradiation apparatus of this invention was applied. It is a figure which shows the state at the time of the exposure processing in the contact exposure apparatus shown in FIG. It is a graph which shows the relationship between the ratio A and the illuminance uniformity, and the relationship between the ratio A and the illuminance. It is a figure which shows the light absorption distribution in the thickness direction (depth direction) of the object to be irradiated when the viewing angle on a light irradiation surface is large. It is a schematic diagram which shows the viewing angle on the light irradiation surface. It is a schematic diagram which shows the outline of the structure in the example of the conventional light irradiation apparatus using LED. It is a schematic diagram which shows the outline of the structure in another example of the conventional light irradiation apparatus using LED. It is a schematic diagram which shows the outline of the structure in still another example of the conventional light irradiation apparatus using LED.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1A is a perspective view showing an outline of a configuration in an example of the light irradiation device of the present invention. FIG. 1B is a cross-sectional view taken along a plane extending in the x-direction and the z-direction in the light irradiation device shown in FIG. 1A. FIG. 2 is a plan view showing an outline of the configuration in an example of the light source unit.
This light irradiation device includes a light irradiator 1 composed of a light source unit 10 in which a plurality of LEDs 12 are arranged on the same plane, and a reflection unit 20 that reflects light from the light source unit 10.

The light source unit 10 has a long substrate 11 in one direction (vertical direction in FIG. 2, hereinafter, this direction is referred to as “y direction”), and on the substrate 11, for example, a plurality of chip-shaped LEDs 12 are formed. , The substrate 11 is arranged side by side in the y direction (longitudinal direction) and the direction orthogonal to the y direction (the left-right direction in FIG. 2, hereinafter, this direction is referred to as the "x direction"). In this example, the LEDs 12 adjacent to each other in the y direction are arranged so as to be displaced from each other in the x direction, so that the plurality of LEDs 12 are arranged in a staggered pattern on the entire substrate 11. Each LED 12 is arranged in a posture in which the optical axis extends in a direction orthogonal to each of the x direction and the y direction (the direction perpendicular to the paper surface in FIG. 2, hereinafter, this direction is referred to as the "z direction"). The area shown by the broken line in FIG. 2 is the LED arrangement area 15, and O indicates the center position thereof.

The LED 12 may have the same central emission wavelength or different central emission wavelengths, but it is preferable to use a plurality of types of LEDs having different central emission wavelengths. As a result, the processing of the object to be irradiated can be performed with light having a plurality of wavelengths instead of light having a single wavelength. For example, in the case of a thick-film resist curing process, the vicinity of the surface can be cured with light of a short wavelength, and the deep part can be cured with light of a long wavelength, and as a result, high-resolution resist curing becomes possible.

The reflecting portion 20 is formed of, for example, a cylindrical hollow body, and includes an axis extending in the z direction (hereinafter, referred to as a “reference axis”) C including the center position O of the LED arrangement region in the light source portion, and is in the x direction. And has a structure symmetrical with respect to the virtual plane F extending in the z direction (symmetrical in FIG. 1B). Although not shown, the reflecting portion 20 has a structure symmetrical with respect to a virtual plane extending in the y direction and the z direction including the reference axis C. The reflecting portion 20 preferably has a polygonal opening shape at the light emitting side opening end. With such a configuration, a plurality of light irradiators can be arranged without a gap, and the above effect can be surely obtained.

Thus, in the above-mentioned light irradiation device, the reflecting portion 20 has a form in the xz cross section or the yz cross section including the reference axis C, which spreads outward with respect to the reference axis C toward the front in the light emission direction. The configuration satisfies the following relationships (1) to (3).

Relationship (1): When the inclination angle of the first virtual line connecting the end position on the light source side of the reflection unit 20 and the opening edge position on the light emission side of the reflection unit 20 with respect to the z direction is θ ₁ . 15 ° ≤ θ ₁ ≤ 37.4 °.
When the inclination angle θ ₁ is too small, it becomes difficult to reduce the size of the viewing angle on the light irradiation surface, as shown in the results of Comparative Example 7 and Comparative Example 17 described later. On the other hand, when the inclination angle θ ₁ is excessive, it becomes difficult to reduce the size of the viewing angle on the light irradiation surface, as shown in the result of Comparative Example 10 described later.

Relationship (2): The same z-direction level position (hereinafter referred to as "reference point") as the plane on which the light emitting surface of each LED 12 is located on the reference axis C, and the light emitting side opening edge of the reflecting unit 20. When the inclination angle of the second virtual line connecting the position with respect to the reference axis C is θ ₂ , θ ₁ <θ ₂ and 24.8 ° ≤ θ ₂ ≤ 41.2 °.
If the tilt angle θ ₂ is too small, it becomes difficult to reduce the size of the viewing angle on the light irradiation surface. As shown in the results of Comparative Example 4 and Comparative Example 5 described later, the viewing angle increases as the value of _{θ 1} decreases, so it is assumed that the configuration satisfies the relationship (1) with _{respect to θ 1.} In this case, the size of the viewing angle is smaller than that of the light irradiation device according to Comparative Example 4, but it is expected to be larger than the size of the viewing angle according to each of the examples. On the other hand, when the inclination angle θ ₂ is excessive, as shown in the results of Comparative Example 12 and Comparative Example 15 described later, it becomes difficult to reduce the size of the viewing angle on the light irradiation surface. It becomes difficult to obtain sufficiently high illuminance uniformity.

Relationship (3): When the ratio of the width (Wa) of the LED arrangement area 15 in the light source unit 10 to the aperture width (Wb) of the reflection unit 20 is A (= Wa / Wb), 0.008 ≦ A ≦ 0 Be .5.
When the ratio A is too small, it becomes difficult to obtain a sufficiently high illuminance on the light irradiation surface as shown in the results of Comparative Examples 19 and 20 and FIG. 7 which will be described later. On the other hand, when the ratio A is excessive, it becomes difficult to obtain a sufficiently high illuminance uniformity as shown in FIG.

The reflecting unit 20 in this example includes a pair of first mirror elements 21 facing each other in the x direction and a pair of second mirror elements 25 facing each other in the y direction, and is formed as a substantially quadrangular pyramid trapezoid as a whole. It is composed of a cylindrical mirror.

As shown in FIG. 3, the first mirror element 21 is continuous with the flat plate-shaped first inclined surface portion 22 and the lower ends of the first inclined surface portion 22 extending in an inclined direction with respect to the z direction in the xz cross section including the reference axis C. It has a flat plate-shaped second inclined surface portion 23 that extends inclined with respect to the z direction. The inclination angles of the first inclined surface portion 22 and the second inclined surface portion 23 with respect to the z direction are set to different sizes while satisfying the above relationships (1) to (3).

That is, the upper end position β of the first inclined surface portion 22 and the lower end position of the second inclined surface portion 23 (light of the reflecting portion 20) of the first mirror element 21 located at the same z-direction level position as the LED arrangement surface 10a of the light source unit 10. _{The inclination angle θ 1 of} the first virtual line L1 connecting the exit side opening edge edge) γ with respect to the z direction is set to a size satisfying 15 ° ≤ θ _{1 ≤ 37.4 °.} Further, the inclination angle θ of the second virtual line L2 connecting the reference point δ and the lower end position of the second inclined surface portion 23 (the position of the opening edge on the light emitting side of the reflecting portion 20) γ with respect to the reference axis C (z direction). ₂ is a size that satisfies _{θ 1} <θ ₂ and 24.8 ° ≤ θ _{2 ≤ 41.2.} Further, the ratio A (= Wa / Wb) of the width of the LED arrangement region 15 (dimension in the x direction in FIG. 3) Wa in the light source unit 10 to the opening width Wb in the x direction of the reflection unit 20 is 0.008 ≦. The size satisfies A ≦ 0.5.

The magnitudes of the tilt angle θ ₁ and the tilt angle θ ₂ are such that the viewing angle on the light irradiation surface LS is 40 ° or less, more preferably 30 ° or less, within the range satisfying the above relationships (1) to (3). It is preferable that it is set so as to be.
When the viewing angle is, for example, 40 ° or less, as shown in FIG. 4, the bias of light absorption in the thickness direction (depth direction) of the object to be irradiated can be suppressed to be small, and the light treatment process can be performed. The accuracy can be increased. In FIG. 4, the vertical direction indicates the thickness direction of the object to be irradiated, and the horizontal direction indicates the position of the object to be irradiated in the surface direction. In addition, La indicates a light absorption region.

The inner surface 21a of the first mirror element 21, that is, the inner surface of the first inclined surface portion 22 and the inner surface of the second inclined surface portion 23 constitutes a reflecting surface that reflects a part of the light from the LED 12 (light having a large radiation angle). The inner surface of the first inclined surface portion 22 and the inner surface of the second inclined surface portion 23 are preferably diffuse reflection surfaces. Since the inner surface 21a of the first mirror element 21 is a diffuse reflection surface, it is possible to improve the uniformity of illuminance on the light irradiation surface LS even when the irradiation distance (work distance WD) is small. It becomes easier to maintain high illuminance.

The diffuse reflection surface can be formed, for example, by subjecting the inner surface 21a of the first mirror element 21 to dimple processing to form dimples. With such a configuration, it is possible to increase the light mixing property and increase the illuminance uniformity on the light irradiation surface. Further, the diffusive reflective surface may be formed, for example, by providing a diffuser or by forming the inner surface 21a of the first mirror element 21 with a large number of flat surfaces, and even in such a case. , The light mixing property can be increased.

The second mirror element 25 is composed of, for example, a planar mirror extending at an angle with respect to the z direction. Similarly, the inner surface of the second mirror element 25 is preferably a diffuse reflection surface.

Thus, in the above-mentioned light irradiation device, the width Wa of the LED arrangement region 15 in the light source unit 10 is sufficiently smaller than the opening width Wb of the reflection unit 20 in the xz cross section including the reference axis C, and the light source unit 10 Is configured such that a plurality of LEDs 12 are densely arranged. Moreover, since the reflecting portion 20 has a specific form, the emission angle of the light directly emitted from the LED 12 through the opening of the reflecting portion 20 and the reflected light reflected and emitted by the reflecting portion 20 are emitted. The emission angle of is regulated. That is, the light directly emitted from the light source unit 10 to the light irradiation surface LS is largely restricted to a part of the light having a small emission angle. On the other hand, the light having a large emission angle from the LED 12 is reflected by the reflecting unit 20 and indirectly emitted toward the light irradiation surface LS. However, since the inner surface 21a of the first mirror element 21 reflects the reflected light toward the reference axis C in the x direction, the emission angle of the reflected light is suppressed to be small.
Therefore, according to the above-mentioned light irradiation device, as shown in the results of Examples described later, the viewing angle on the light irradiation surface LS can be suppressed to be small. Further, according to the above-mentioned light irradiation device, the light mixing property of the light from each LED 12 is increased. Therefore, even if a problem such as a variation in the light emission output of the LED or a decrease in the amount of light of an arbitrary LED with time occurs, the light from each LED 12 is superimposed on the light irradiation surface LS to compensate each other. By matching, the uniformity of illuminance on the light irradiation surface LS can be increased, and highly stable light irradiation can be performed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made.
For example, the reflecting portion is not limited to the one having the configuration according to the above embodiment as long as it satisfies the above relationships (1) to (3). For example, the first mirror element constituting the reflecting portion does not need to have a configuration having a plurality of inclined surface portions having different inclination angles with respect to the z direction.
Furthermore, the reflecting portion does not have to be arranged in a state where the end portion on the light source portion side is located at the same z-direction level position as the light source portion, and even if the reflecting portion is arranged on the front side in the light emitting direction from the light source portion. good.
Furthermore, the light irradiator of the present invention may be configured to include a plurality of light irradiators. In such a configuration, as described above, since the opening shape of the light emitting side opening end of the reflecting portion in the light irradiator is polygonal, the light irradiators can be arranged without a gap, and the above effect. Can be surely obtained.

The light irradiation device as described above can be suitably used as a light source of, for example, an exposure device used for exposure of a semiconductor substrate or a liquid crystal substrate by photolithography and other microfabrication.

FIG. 5 is a diagram schematically showing a configuration in an example of a contact exposure apparatus to which the light irradiation apparatus of the present invention is applied.
This contact exposure apparatus (hereinafter, simply referred to as “exposure apparatus”) irradiates an object to be irradiated (hereinafter, also referred to as “work”) W with exposure light (for example, ultraviolet light) via a photomask M. For example, a light irradiation unit 5 configured by a light irradiation device provided with the light irradiation device 1 shown in FIG. 1, a mask stage 50 holding a photomask M having a pattern to be exposed (transferred) to the work W, and a work. The work stage 55 that holds the W, the alignment mechanism 60 for aligning the work W held by the work stage 55 and the photomask M, the work transfer mechanism that conveys the work W, and each operation of the apparatus. It is equipped with a control unit (not shown) for controlling. As the work W, for example, a substrate material such as a printed circuit board, a semiconductor substrate, or a liquid crystal substrate can be exemplified.

The mask stage 50 includes a mask holding means (not shown) that holds the peripheral edge of the upper surface of the photomask M by, for example, vacuum suction.
The mask stage 50 may be configured to be movable in the XYθ direction in a horizontal plane along the work mounting surface of the work stage 55 by an appropriate stage drive mechanism (not shown).

The work stage 55 is provided with a work holding means (not shown) for holding the work W placed on the flat work mounting surface by, for example, vacuum suction.
The work stage 55 is configured to be movable in the XYZθ direction (plane direction along the work mounting surface, height direction, and rotation direction about an axis perpendicular to the work mounting surface) by the stage drive mechanism 56. There is. The stage drive mechanism 56 includes, for example, an XYθ stage 57 and an elevating stage (Z stage) 58.

The alignment mechanism 60 simultaneously detects the mask alignment mark Am formed on the photomask M, the work alignment mark Aw formed on the work W, the alignment mark detecting means 61, and the alignment mark detecting means 61 as a light irradiation unit. A moving mechanism (not shown) for inserting or retracting from the position between the mask stage 50 and the mask stage 50 is provided. As the alignment mark detecting means 61, an imaging device such as a CCD camera can be used.

The work transfer mechanism includes a carry-in side transfer mechanism 65a for carrying in the work W before the exposure process and a carry-out side transfer mechanism 65b for carrying out the work W after the exposure process. The carry-in side transport mechanism 65a and the carry-out side transport mechanism 65b are, for example, a plurality of rollers rotatably provided on each of a plurality of conveyor shafts 66 extending in a horizontal plane parallel to each other and in a direction orthogonal to the transport direction of the work W. It is composed of a roller conveyor provided with 67.
Further, the work transfer mechanism includes the carry-in side transfer mechanism 70a for transferring the work W on the conveyor in the carry-in side transfer mechanism 65a onto the work stage 55, and the work W after the exposure process to be carried out from the work stage 55. The carry-out side transfer mechanism 70b for transferring onto the conveyor of the transfer mechanism 65b is provided. The carry-in side transfer mechanism 70a and the carry-out side transfer mechanism 70b include, for example, a transfer arm 71 that attracts and holds the work W, and the transfer arm 71 is positioned between the work stage 55 and the mask stage 50. It is provided so that it can be inserted and retracted in.

In the above exposure apparatus, the exposure process of the work W is performed as follows.
First, the work W carried into the apparatus by the carry-in side transport mechanism 65a is transferred onto the work stage 55 by the carry-in side transfer mechanism 70a. That is, after the work W on the conveyor is attracted and held by the transfer arm 71, the transfer arm 71 is moved in the horizontal direction while holding the work W and is positioned above the work stage 55. In this state, the work W is placed on the work stage 55 by releasing the suction holding of the work W by the transfer arm 71. After that, the transfer arm 71 is retracted to a predetermined position. The work W placed on the work stage 55 is, for example, sucked and held by the work holding means provided on the work stage 55.

Next, the alignment mark detecting means 61 detects the mask alignment mark Am in the photomask M and the work alignment mark Aw in the work W. As a result, the position information of the work W on the work stage 55 and the position information of the photomask M held in the mask stage 50 are acquired, and based on the position information, the work W and the photomask M on the work stage are acquired. Alignment with is performed. That is, the control unit sets the alignment amounts in the X direction, the Y direction, and the θ direction based on the detected position information, and depending on the alignment amount, for example, the XYθ stage 57 constituting the stage drive mechanism 56 is set. Move. As a result, the work W and the photomask M are aligned. Here, the alignment of the work W and the photomask M may be performed by moving one of the work stage 55 and the mask stage 50 relative to the other, and therefore, the alignment amount set by the mask stage 50 is set. It may be driven according to.

After the alignment between the photomask M and the work W is completed, as shown in FIG. 6, the work stage 55 is raised by the elevating stage 58 constituting the stage drive mechanism 56, and the surface of the work W is brought into close contact with the mask M. It is considered to be in a state. In this state, the exposure light from the light irradiation unit 5 (for example, UV light, indicated by a white arrow in FIG. 6) of the work W on the work stage 55 via the photomask M held on the mask stage 50. The surface is irradiated, whereby the pattern formed on the photomask M is exposed (transferred) to the work W.
When the exposure process for the work W is completed, the work stage 55 is lowered by the elevating stage 58 constituting the stage drive mechanism 56, and the work W on the work stage 55 is transferred to the conveyor in the carry-out side transport mechanism 65b by the carry-out side transfer mechanism 70b. Reprinted above. Then, the work W is carried out of the apparatus by the carry-out side transport mechanism 65b.

Therefore, according to the above-mentioned exposure device, since the above-mentioned light irradiation device constituting the light irradiation unit 5 can obtain high uniformity of illuminance on the light irradiation surface, the exposure process of the work W is processed. It can be performed with high resolution without causing unevenness.

Specific examples of the present invention will be described below, but the present invention is not limited thereto.

<Examples 1 to 10, Comparative Examples 1 to 22>
According to the configurations shown in FIGS. 1A and 1B, a light irradiation device according to the present invention having the specifications shown in Table 1 below was manufactured. In addition, a light irradiation device for comparison having the specifications shown in Table 2 below was manufactured.
In each light irradiation device, as shown in FIG. 2, the light source unit is configured such that about 2000 LEDs are arranged in the x direction and the y direction in the LED arrangement area. Each LED has a light emission angle of 60 °. The LED arrangement area has a dimension (Wa) in the x direction as shown in Tables 1 and 2 below, and a dimension in the y direction is 360 mm. Further, in the "LED arrangement" in Table 1, "10 rows" means that the number of LEDs arranged in the x direction in FIG. 2 is 10, and "n parallel" means 10 rows of LED arrangements. When one LED group is used, it is shown that the number of LED groups arranged in the x direction in FIG. 2 is n.
A hammer pattern or a stucco pattern is provided on the inner surface of each of the first mirror element and the second mirror element constituting the reflecting portion to form a diffuse reflection surface.

For each of the light irradiation devices according to Examples 1 to 10 and Comparative Examples 1 to 22, the viewing angle on the light irradiation surface arranged at a position 374 mm away from the light emitting side opening end surface of the reflecting portion in the z direction. And investigated the illuminance uniformity on the light-irradiated surface. When the viewing angle defined below is 40 ° or less, the illuminance uniformity is 75% or more, and the illuminance is 20 mW / cm ² or more, "○" is used. The case of dissatisfaction was evaluated as "x". Further, the case where the viewing angle was 30 ° or less, the illuminance uniformity was 80% or more, and the illuminance was 30 mW / cm ² or more was evaluated as “⊚”. The results are shown in Tables 1 and 2 below.

The effective viewing angle was obtained from the half width of the incident angle intensity distribution on the light irradiation surface, and this value was used as the viewing angle on the light irradiation surface.
The illuminance is an average value of the illuminance measured at a plurality of measurement points on the light irradiation surface.
The illuminance uniformity is determined by (Equation) (Ea-ΔE) / Ea when the average value of the illuminance measured at a plurality of measurement points on the light irradiation surface is Ea and the illuminance distribution width at each of the plurality of measurement points is ΔE. Defined by [%].

As is clear from this result, in the light irradiation devices according to Examples 1 to 10, the viewing angle on the light irradiation surface can be suppressed to be small, and sufficiently high illuminance can be obtained on the light irradiation surface. It was confirmed that high uniformity of illuminance could be obtained.

In addition, the relationship between the size of the ratio A and the illuminance uniformity was investigated for each of the plurality of light irradiation devices in which _{θ 2 was set to an arbitrary size.} The results are shown in FIG. The curves (A) to (F) shown in FIG. 7 show _{the values of θ 2} at 21.7 °, 29.9 °, 34.8 °, 41.2 °, 48.9 °, and 57.9 °, respectively. The result of the light irradiation device is shown. The curve (G) shows the relationship between the magnitude of the ratio A and the illuminance value.
As is clear from the results shown in FIG. 7, the higher the value of the ratio A, the lower the illuminance uniformity tends to be. Especially in the range where the value of the ratio A exceeds 0.5, the illuminance uniformity (light mixing property). ) Was confirmed to be significantly worse. Further, it was confirmed that when the value of the ratio A was less than 0.008, the illuminance value was remarkably lowered. Therefore, from the viewpoint of illuminance uniformity and illuminance, when the ratio A satisfies the above relationship (3) (0.008 ≦ A ≦ 0.5), a sufficiently high illuminance can be obtained on the light irradiation surface. Moreover, it was confirmed that high illuminance uniformity can be obtained.

1 Light irradiator 5 Light irradiator 10 Light source part 10a LED placement surface 11 Board 12 LED
15 LED arrangement area 20 Reflecting part 21 First mirror element 21a Inner surface (reflecting surface)
22 First inclined surface part 23 Second inclined surface part 25 Second mirror element 30 Light source part 30a Segment light source 31 LED
32 Substrate 35 Light guide 40 Aperture array 45 Mask 50 Mask stage 55 Work stage 56 Stage drive mechanism 57 XYθ stage 58 Elevating stage 60 Alignment mechanism 61 Alignment mark detection means 65a Carry-in side transport mechanism 65b Carry-out side transport mechanism 66 Conveyor shaft 67 Roller 70a Carry-in side transfer mechanism 70b Carry-out side transfer mechanism 71 Transfer arm Am Mask alignment mark Aw Work alignment mark C Reference axis F Virtual plane LS Light irradiation surface M Photomask O LED placement area center position W Irradiation target Object (work)

Claims (6)

When the three directions orthogonal to each other are the x direction, the y direction, and the z direction, a plurality of LEDs whose optical axes extend in the z direction are arranged in the x direction and the y direction on the same plane extending in the x direction and the y direction. In a light irradiation device including a light source unit arranged in and a reflection unit that reflects light from the light source unit.
When the axis extending in the z direction including the center position of the LED arrangement region in the light source unit is used as the reference axis, the xz cross section or the yz cross section including the reference axis
The reflective portion has a relationship of 0.008 ≦ A ≦ 0.5 when the ratio of the width (Wa) of the LED arrangement area and the opening width (Wb) of the reflective portion is A (= Wa / Wb). It has a form that spreads outward with respect to the reference axis toward the front in the light emitting direction so as to satisfy the above .
The angle of inclination of the first virtual line connecting the position of the end of the reflection on the light source side and the position of the edge of the light emitting side opening of the reflection is θ ₁ on the reference axis. The inclination angle of the second virtual line connecting the same z-direction level position as the plane on which the light emitting surface of each LED is located and the position of the light emitting side opening edge of the reflecting portion with respect to the reference axis is θ _2. When the light irradiation device is used, the light irradiation device satisfies the following relationships (1) and (2).
(1) 15 ° ≤ θ ₁ ≤ 37.4 °
(2) 24.8 ° ≤ θ ₂ ≤ 41.2 °, θ ₁ <θ ₂ The light irradiation device according to claim 1, wherein the plurality of LEDs constituting the light source unit are made of a plurality of types having different central emission wavelengths. The light irradiation device according to claim 1 or 2, wherein the reflecting portion has a light diffusing reflecting surface. The light irradiation device according to claim 3, wherein the diffusive reflective surface of the reflective portion is composed of a large number of flat surfaces. The light irradiation device according to claim 3, wherein the diffusive reflective surface of the reflective portion is composed of dimples formed on the inner surface of the reflective portion. The light irradiation device according to any one of claims 1 to 5, wherein the reflecting portion has a polygonal opening shape at the light emitting side opening end.

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