JP2020091402A - Light source device for exposure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure light source device which supplies light having an angle distribution equivalent to that of a light source device using a discharge lamp by using a plurality of semiconductor laser light sources. SOLUTION: A plurality of collimating optical systems that convert a plurality of semiconductor laser light sources and light bundles emitted from the semiconductor laser light sources into substantially parallel light bundles and emit the light bundles, and a light flux emitted from the collimating optical system. A condensing optical system 12 for condensing 22 and an optical waveguide including a circular incident surface are provided, and each light bundle 22 emitted from a plurality of semiconductor laser light sources on the incident surface 20 of the condensing optical system When the optical axes 15 of the condensing optical system are virtually rotated and arranged in the same radial direction, some of the adjacent light fluxes overlap, and the plurality of semiconductor laser light sources condense. On the incident surface of the optical system, the number of light fluxes belonging to the light flux group having the same distance from the optical axis of the condensing optical system is based on the nth light bundle group whose distance from the optical axis is the nth closest. , Arranged so as to gradually decrease as the distance from the optical axis increases. [Selection diagram] FIG. 3B

Description

The present invention relates to an exposure light source device, and more particularly to an exposure light source device that uses light emitted from a semiconductor laser light source.

Conventionally, a discharge lamp having a high light intensity has been used for an exposure device used in a manufacturing process of a printed circuit board or the like. In recent years, with the progress of solid-state light source technology, studies are being made to replace a discharge lamp with a highly efficient and long-life semiconductor laser light source.

With a single semiconductor laser light source, the emitted light flux is small as a light source of the exposure apparatus. In order to obtain high intensity light, a method of arranging a plurality of semiconductor laser light sources and condensing the light emitted from each semiconductor laser light source can be considered. For example, Patent Document 1 discloses an exposure apparatus for a flexible printed circuit board, which includes a plurality of semiconductor laser light sources and optical fibers corresponding to the respective semiconductor laser light sources.

JP, 2001-272791, A

To collect light emitted from a plurality of semiconductor laser light sources, a method of collecting light using a collimator lens or a condenser lens can be considered. However, the present inventors replace the light source device for the exposure apparatus with a light source device that condenses light emitted from a plurality of semiconductor laser light sources by an optical system from a light source device that uses a discharge lamp. Upon examination, they found that the following problems existed. Hereinafter, description will be given with reference to the drawings.

FIG. 7A is a drawing schematically showing an exposure light source device including a semiconductor laser light source 100, a collimator lens 101 (also referred to as “collimation lens”), a condenser lens 102, and a rod integrator 104. .. FIG. 7A schematically illustrates the traveling paths of each principal ray and each ray bundle of light (laser light) emitted from the plurality of semiconductor laser light sources 100. In this specification, a light beam emitted from the center of the semiconductor laser light source 100 in parallel with the optical axis 140 is referred to as a “main light beam”, and a bundle of light beams emitted from the semiconductor laser light source 100 is referred to as a “bundle light beam”. A ray bundle".

In FIG. 7A, an axis orthogonal to the incident surface 105 of the rod integrator 104 is an optical axis 140. The optical axis 140 direction is the Z direction, the plane orthogonal to the Z direction is the XY plane, and the incident angle of light with respect to the incident surface 105 is θ1.

The light flux (121a, 121b, 121c) emitted from the semiconductor laser light source 100 is converted into a substantially parallel light flux (122a, 122b, 122c) by the collimator lens 101. The bundles of rays (122a, 122b, 122c) are parallel to each other, do not overlap each other, and enter the condenser lens 102 at the subsequent stage. The bundle of rays (122a, 122b, 122c) incident on the condenser lens 102 is converted into a bundle of rays (123a, 123b, 123c) that converges toward the focus position 150 of the condenser lens 102.

A rod integrator 104 is arranged in the subsequent stage of the condenser lens 102 in order to make the light intensity distribution of the light bundles (123a, 123b, 123c) condensed by the condenser lens 102 uniform. The rod integrator 104 is arranged so that the incident surface 105 is aligned with the focal position 150 of the condenser lens 102.

Here, since the semiconductor laser light source 100 and the collimator lens 101 cannot be arranged in close contact with each other, a gap is generated between the light beam bundles (122a, 122b, 122c), and light is incident on the incident surface 103 of the condenser lens 102. There are places where it exists and places where it does not exist, and uneven illumination occurs.

Therefore, a part of the light flux (123a, 123b, 123c) converted by the condenser lens 102 so as to be condensed at the focal position 150 of the light generated on the emission surface of the condenser lens 102 is generated. There is no light in the angle range, or a region 130 having extremely low light intensity is generated as compared with the vicinity of the principal rays (110a, 110b, 110c).

Further, a case where the entrance surface 103 of the condenser lens 102 is viewed on the XY plane will be described. FIG. 7B is a schematic view of the condenser lens 102 of FIG. 7A when viewed from the incident surface 103 side in the Z direction. For convenience of description, the same number of semiconductor laser light sources 100 and collimating lenses 101 are aligned in the Y direction at the same intervals as in the X direction, and the chief ray 110b of the ray bundle 122b is aligned with the optical axis 140. I was supposed to do it. In addition, in order to facilitate understanding of the relative positional relationship on the XY plane, FIG. 7A shows that in addition to the bundle of rays (122a, 122b, 122c) incident on the incident surface 103 of the condenser lens 102, The rod integrator 104 located in the +Z direction from the optical lens 102 is also illustrated.

Each ray bundle (122a, 122b, 122c) has an elliptical shape on the incident surface 103 of the condenser lens 102. FIG. 8 is a perspective view schematically showing the structure of the semiconductor laser chip 200. In the case of a so-called “edge emitting type” semiconductor laser chip 200 as shown in FIG. 8, it is known that the light flux 121 emitted from the emitter 201 has an elliptic cone shape. Therefore, as shown in FIG. 7B, the cross section of each ray bundle (122a, 122b, 122c) is elliptical. The semiconductor laser light source 100 shown in FIG. 7A is a laser light source in which the semiconductor laser chip 200 shown in FIG. 8 is casing. The semiconductor laser light source 100 is a laser light source that emits light so that the principal rays (110a, 110b, 110c) pass through the center of the light emission window.

In the present specification, of the two directions (X direction and Y direction) orthogonal to the optical axis (Z direction shown in FIG. 8), the direction in which the divergence angle of the ray bundle 121 is large (Y direction shown in FIG. 8) is The “Fast axis direction” is called, and the direction in which the divergence angle of the light bundle 121 is small (X direction shown in FIG. 8) is called the “Slow axis direction”. Here, the divergence angle is an angle formed between the principal ray (110a, 110b, 110c) and a ray propagating at a light intensity of 1/e ² of the principal ray (110a, 110b, 110c) having the maximum light intensity. Points twice the angle.

As shown in FIG. 7B, on the incident surface 103 of the condenser lens 102, each ray bundle (122a, 122b, 122c) has no light or is in the vicinity of the principal ray on a concentric circle centered on the optical axis 140. In comparison, a region 130 having extremely low light intensity is generated. This is because the semiconductor laser light source 100 and the collimator lens 101 cannot be arranged in close contact with each other for the same reason as described above.

Since the rod integrator 104 guides the incident light to the emission surface 106 (see FIG. 7A) while repeatedly totally reflecting the incident light on the side surface, the light intensity distribution at the position on the XY plane (hereinafter, “position distribution”). However, the light intensity distribution for each incident angle θ1 on the incident surface 105 of the rod integrator 104 (hereinafter, referred to as “angle distribution”) is also maintained on the emitting surface 106. However, there is no effect of improving the uniformity of angular distribution.

Therefore, even if the rod integrator 104 is used, a region where light does not exist in a part of the angular range or where the light intensity is extremely low as compared with the vicinity of the chief ray cannot be eliminated. That is, the unevenness of the angular distribution generated on the emission surface of the condenser lens 102 is not eliminated even by the light emitted from the emission surface 106 of the rod integrator 104.

Here, the angular distribution of the light emitted from the light source device using the discharge lamp 160 will be described. FIG. 9 is a drawing schematically showing a configuration example of a light source device using the discharge lamp 160. As shown in FIG. 9, in a light source device using a discharge lamp 160, a discharge gas is enclosed in a tube body 161, and light is emitted from a light emitting section 164 by being discharged between a cathode 162 and an anode 163. ..

A part of the light emitted from the discharge lamp 160 is reflected by the elliptical mirror 165 and condensed on the incident surface 105 of the rod integrator 104. The elliptic mirror 165 has an elliptic arc shape with two focal points, the light emitting section 164 and the entrance surface 105 of the lot integrator 104.

As shown in FIG. 9, the maximum incident angle of light on the incident surface 105 of the rod integrator 104 is set to the angle α1. Further, of the light emitted from the light emitting unit 164, the light traveling in the vicinity of the optical axis 15 is blocked by a part of the tube body 161, and does not reach the incident surface 105 of the rod integrator 104. Therefore, there is no light in the region where the incident angle is smaller than the angle α2.

That is, as shown in FIG. 9, the angle distribution of the light source device using the discharge lamp 160 is such that light does not exist in the angle range smaller than the angle α2 from the optical axis 140 and is in the range from the angle α2 to the angle α1. Light is distributed continuously. Moreover, among the lights uniformly emitted from the discharge lamp 160 in all directions, a part of the lights reflected by the elliptical mirror 165 is denser as the incident angle on the incident surface 105 of the rod integrator 104 is smaller. And the light intensity increases.

FIG. 10 is a graph schematically showing the angular distribution of the light emitted from the light source device using the discharge lamp 160. As shown in FIG. 10, the angular distribution of the light source device using the discharge lamp 160 is such that there is no light in the portion where the incident angle is close to 0°, and the angle within the angular range in which the condensed light exists. Has a peak in a small range, and the light intensity continuously decreases as the angle increases. The position distribution is made uniform by the lot integrator 104.

Since the light source device for the exposure apparatus is replaced with the light source device using the semiconductor laser light source from the light source device using the discharge lamp 160, the light source device using the semiconductor laser light source is equivalent to the light source device using the discharge lamp 160. It is expected that the light has the same position distribution and angle distribution as the light source device using the discharge lamp 160.

However, as described above, the light emitted from the plurality of semiconductor laser light sources 100 is converted into light equivalent to that when the discharge lamp 160 is used, only by the configuration of the collimator lens 101, the condenser lens 102, and the rod integrator 104. I can't. That is, it has been found that the position distribution of the light source device using the discharge lamp 160 can be made equal, but the angular distribution is not equal.

In view of the above problems, it is an object of the present invention to provide an exposure light source device that uses a plurality of semiconductor laser light sources to supply light having an angular distribution equivalent to that of a light source device that uses a discharge lamp.

The exposure light source device according to the present invention is
A plurality of semiconductor laser light sources,
A plurality of collimating optical systems, which are arranged corresponding to the plurality of semiconductor laser light sources, convert the light flux emitted from the semiconductor laser light source into a substantially parallel light flux, and emit the light.
A condensing optical system that includes an incident surface on which the light flux emitted from the collimating optical system is incident, and that condenses the light flux emitted from the collimating optical system,
An optical waveguide including a circular incident surface, which is arranged at a position where a bundle of rays emitted from the condensing optical system is condensed,
The respective light fluxes emitted from the plurality of semiconductor laser light sources on the entrance surface of the condensing optical system are virtually rotated about the optical axis of the condensing optical system and are directed in the same radial direction. When arranged side by side, some of the adjacent ray bundles overlap,
In the plurality of semiconductor laser light sources, on the incident surface of the condensing optical system, the number of ray bundles belonging to the bundle of ray bundles having the same distance from the optical axis of the condensing optical system is the distance from the optical axis. It is characterized in that it is arranged so as to gradually decrease with increasing distance from the optical axis, with the n-th ray bundle group close to the n-th reference.

In the exposure light source device, on the incident surface of the condensing optical system, the respective light fluxes emitted from the respective semiconductor laser light sources are rotated about the optical axis of the condensing optical system and directed in the same radial direction. When they are arranged side by side, some of the adjacent ray bundles overlap. The process of rotating the condensing optical system about the optical axis and arranging them in the same radial direction will be described later in the description of FIG. 3B.

According to the above configuration, as shown in FIG. 7B, on a concentric circle centered on the optical axis of the condensing optical system, light does not exist between adjacent ray bundle groups, or compared with the vicinity of the chief ray. Therefore, a region having extremely low light intensity does not occur. That is, in the angle direction with respect to the optical axis, there is no range where light does not exist in a part of the region where light exists. Details will be described later in the description of FIG. 3B.

n is an arbitrary natural number. Further, with the n-th ray bundle group whose distance from the optical axis is closest to the nth as a reference, it means that the ray bundle group gradually decreases as the number of n increases from the arbitrarily determined value n. It means that the number of belonging ray bundles decreases intermittently or continuously. That is, the number of ray bundles belonging to the ray bundle group next to the optical axis next to the n-th ray bundle group is the same as the number of ray bundles belonging to the n-th ray bundle group, or of the ray bundles belonging to the n-th ray bundle group. This means that the plurality of semiconductor laser light sources are arranged so as to be less than the number.

The larger the number of light bundles belonging to the light bundle group having the same distance from the optical axis of the condensing optical system, the higher the light intensity for each incident angle on the incident surface of the optical waveguide. That is, according to the above configuration, in the range where the angle of incidence on the incident surface of the optical waveguide is larger than the predetermined angle of incidence, the light intensity gradually decreases as the angle of incidence increases, and the light is emitted from the light source device using the discharge lamp. Light having an angular distribution close to that of the generated light is obtained.

The same distance from the optical axis is not limited to the same distance from the optical axis. If the distance error is 1 mm or less, the light bundles belonging to the same light bundle group are included. May be regarded as

The exposure light source device includes an optical waveguide whose incident surface is circular. Since the incident surface is circular, the light emitted from the optical waveguide is converted into uniform light on a concentric circle centered on the optical axis while maintaining the incident angle on the incident surface. Details will be described later in the description of FIG. 1B.

In the exposure light source device,
The plurality of semiconductor laser light sources may be arranged on the same plane.

According to the above configuration, since all the semiconductor laser light sources are arranged on the same substrate, it is possible to wire each semiconductor laser light source on the same substrate. Furthermore, the semiconductor laser light source may be cooled by a cooling mechanism on the same substrate.

In the exposure light source device,
In the plurality of semiconductor laser light sources, on the incident surface of the condensing optical system, the number of ray bundles belonging to the bundle of ray bundles having the same distance from the optical axis of the condensing optical system is the distance from the optical axis. The closest first ray bundle group may be used as a reference, and the first ray bundle group may be arranged so as to gradually decrease with distance from the optical axis.

According to the above configuration, the number of ray bundles belonging to the first ray bundle group is at least 2 or more. This is because if the number of the light ray bundles belonging to the first light ray bundle group is 1, the number of the light ray bundles belonging to all the light ray bundle groups becomes 1, and there is no decrease. Then, the light beam bundle is not arranged on the optical axis of the condensing optical system, and light does not exist near the incident angle of 0° on the incident surface of the optical waveguide. Furthermore, within a range of angles larger than the incident angle corresponding to the first bundle of rays, the light intensity gradually decreases as the incident angle increases, and the angle distribution of the light emitted from the light source device using the discharge lamp is further reduced. It is possible to obtain light having a close angular distribution.

In the exposure light source device,
Each of the light fluxes emitted from the plurality of semiconductor laser light sources on the incident surface of the condensing optical system has an elliptical shape whose major axis direction faces the optical axis side of the condensing optical system. I don't care.

According to the above configuration, on the entrance surface of the condensing optical system, the respective light fluxes emitted from the respective semiconductor laser light sources are arranged along the radial direction when rotated about the optical axis of the condensing optical system. Since the major axis directions are aligned with each other, adjacent ray bundles are easily overlapped with each other, and the adjacent ray bundles can be separated from each other as compared with the case where they are aligned in the minor axis direction. Therefore, adjacent semiconductor laser light sources and adjacent collimating optical systems can be arranged more sparsely. If the semiconductor laser light source and the collimating optical system can be arranged sparsely, the degree of freedom of each arrangement can be increased, and a configuration in which wiring is easier can be adopted.

Further, the fact that the major axis direction of the bundle of rays faces the optical axis side of the condensing optical system means that the major axis of the bundle of rays incident on the condensing optical system is It is not limited to the case where the straight line drawn from the axis toward the center of the light beam bundle is parallel, that is, the angle formed by both straight lines is 0°, and the angle includes less than 45°.

In the exposure light source device,
It may include an integrator optical system that homogenizes the position distribution of the light beam emitted from the optical waveguide and emits the light beam.

According to the above configuration, since the integrator optical system improves the uniformity of the position distribution, it is close to the angular distribution of the light emitted from the light source device using the discharge lamp, and the uniformity of the position distribution is improved. You get the light.

According to the present invention, it is possible to provide an exposure light source device that uses a plurality of semiconductor laser light sources to supply light having an angle distribution equivalent to that of a light source device that uses a discharge lamp.

It is drawing which shows typically the structural example of one Embodiment of the light source device for exposure. It is the drawing which showed typically the light which progresses in an optical waveguide in YZ plane view. It is the drawing which showed typically the light which advances in an optical waveguide in XY plane view. 3 is a drawing schematically showing light emitted from an optical waveguide 13. 2 is a schematic view of the condensing optical system of FIG. 1 when viewed from the incident surface side in the Z direction. FIG. 3B is a schematic drawing showing a state in which the light beam bundles on the entrance surface of the condensing optical system shown in FIG. 3A are rotated about the optical axis and arranged in the same radial direction. FIG. It is drawing which expands and shows a set of adjacent light beam bundles on the entrance surface of the condensing optical system shown in FIG. 3B. It is drawing which shows typically the structural example of another embodiment of the light source device for exposure. 4B is a schematic view of the condensing optical system of FIG. 4A when viewed from the incident surface side in the Z direction. FIG. It is drawing which shows typically the structural example of another embodiment of the light source device for exposure. It is drawing which shows the structure of an exposure apparatus typically. It is drawing which showed typically the light source device for exposure comprised by the semiconductor laser light source, the collimating lens, the condensing lens, and the rod integrator. 7B is a schematic view of the condenser lens of FIG. 7A when viewed from the incident surface side in the Z direction. FIG. It is a perspective view which shows the structure of a semiconductor laser chip typically. It is drawing which shows typically the structural example of the light source device using a discharge lamp. It is a graph which shows typically the angular distribution of the light radiate|emitted from the light source device which used the discharge lamp.

An exposure light source device of the present invention will be described below with reference to the drawings. It should be noted that each of the following drawings is a schematic illustration, and the dimensional ratios and the numbers in the drawings do not necessarily match the actual dimensional ratios and numbers.

[First embodiment]
FIG. 1 is a drawing schematically showing a configuration example of a first embodiment of an exposure light source device. The exposure light source device 1 includes a plurality of semiconductor laser light sources 10, a plurality of collimating optical systems 11, a condensing optical system 12, and an optical waveguide 13.

In the first embodiment, the optical waveguide 13 has a cylindrical shape, and in FIG. 1, the axis orthogonal to the incident surface 14 is the optical axis 15 and is arranged so as to coincide with the optical axis of the condensing optical system 12. .. Further, the optical axis 15 direction is the Z direction, the plane orthogonal to the Z direction is the XY plane, and the incident angle of light with respect to the incident surface 14 is θ1. Here, as the optical waveguide 13, specifically, an optical fiber, a cylindrical glass body, or the like can be used.

The semiconductor laser light source 10 is a laser light source in which a semiconductor laser chip is casing. The semiconductor laser light source 10 is a laser light source that emits light so that the principal ray 22a passes through the center of the light emission window.

As shown in FIG. 1, the collimating optical system 11 is a collimating lens that converts a light beam bundle 21 emitted from the semiconductor laser light source 10 into a substantially parallel light beam bundle 22 and emits it. A plurality of collimating optical systems 11 are arranged corresponding to each semiconductor laser light source 10.

As shown in FIG. 1, the condensing optical system 12 is a condensing lens that converts the light beam bundle 22 emitted from the collimating optical system 11 into a light beam bundle 23 that converges toward a focus position and emits the light beam bundle 23.

The optical waveguide 13 shown in FIG. 1 is arranged such that the incident surface 14 is at the focal point of the condensing optical system 12. However, in the present specification, “to be placed at the focal position” means that the position is perfectly coincident with the focal position and that the lens is moved by a distance of ±10% in the direction parallel to the optical axis 15 with respect to the focal length. It is assumed to be a concept including position. The optical axis 15 in FIG. 1 is an axis that is orthogonal to the incident surface 20 of the condensing optical system 12 and passes through the center of the incident surface 20. As shown in FIG. 1, in the present embodiment, the axis passing through the center of the condensing optical system 12 is arranged so as to coincide with the optical axis 15, but the optical axis 15 and the center of the condensing optical system 12 are arranged. The axes to pass do not have to match.

The optical waveguide 13 homogenizes the distribution of the light incident from the incident surface 14 in the circumferential direction around the optical axis 15 while maintaining the angle of incidence angle θ1 with respect to the optical axis 15 from the emission surface 16. The light is emitted at an emission angle θ2 (see FIG. 2A) that is the same as the incident angle θ1.

Here, how the light flux incident on the optical waveguide 13 is converted and emitted will be described. FIG. 2A is a diagram schematically showing light traveling in the optical waveguide 13 in a YZ plan view. As shown in FIG. 2A, the optical waveguide 13 guides the light beam to the emission surface 16 while repeatedly reflecting the incident light on the side surface.

In FIG. 2A, only one light beam is schematically shown, but a plurality of light beam bundles are incident on the optical waveguide 13, and the light beams are aggregated in the optical waveguide 13 and travel, so that the emission surface 16 At, the light flux is emitted as a bundle of rays with a uniform distribution on the XY plane.

Next, a case where the light traveling in the optical waveguide 13 is viewed on the XY plane will be described. FIG. 2B is a diagram schematically showing light traveling in the optical waveguide 13 in XY plan view. As shown in FIG. 2B, the light beam bundle 24 that has entered the optical waveguide 13 is reflected on the inner wall surface of the circular optical waveguide 13. Here, when the light bundle 24 having a constant width is reflected on the circular inner wall surface of the optical waveguide 13, the light bundle 24 advances toward the opposite wall surface while widening the width.

FIG. 2C is a diagram schematically showing the light emitted from the optical waveguide 13. The light bundle 24 travels while repeating reflection on the inner wall surface of the optical waveguide 13, and eventually becomes a light bundle 24 that travels while reflecting all over the inner wall surface of the optical waveguide 13 in the circumferential direction. The light beam bundle 24 that has reached the output surface 16 is output as an annular light beam bundle 25 having an output angle θ2 with the optical axis 15 as the center.

In order that the light emitted from the optical waveguide 13 does not cause illuminance unevenness, as described above, there is no light on the concentric circle with the optical axis 15 as the center, or as compared with the vicinity of the chief ray 22a, It is necessary to arrange the light source and the optical system so that there is no region of low light intensity.

In the first embodiment, the semiconductor laser light sources 10 are arranged on the same plane, and the light beam bundle on the incident surface 20 of the condensing optical system 12 is rotated about the optical axis 15 to be the same. When arranged in the radial direction 30, the adjacent ray bundles are arranged so as to partially overlap each other. Each collimating optical system 11 is also arranged on the same plane so as to correspond to each semiconductor laser light source 10, but neither the semiconductor laser light source 10 nor the collimating optical system 11 may be arranged on the same plane. ..

FIG. 3A is a schematic view of the condensing optical system 12 of FIG. 1 when viewed from the incident surface 20 side in the Z direction. FIG. 3B shows a state in which the light beam bundles 22 on the incident surface 20 of the condensing optical system 12 shown in FIG. 3A are virtually rotated about the optical axis 15 and arranged in the same radial direction 30. It is a schematic drawing shown. As shown in FIG. 3B, each ray bundle 22 arranged in the same radial direction 30 overlaps a part of an adjacent ray bundle 22. In FIG. 3B, the region where the adjacent light beam bundles 22 overlap each other is shown by hatching.

In FIG. 3B, in the incident surface 20 of the condensing optical system 12, when the light beams 22 are rotated about the optical axis 15 and arranged in the same radial direction 30, adjacent light beam bundles 22 partially overlap with each other. There is. FIG. 3C is an enlarged view of a set of adjacent light beam bundles 22 on the entrance surface 20 of the condensing optical system 12 shown in FIG. 3B. As shown in FIG. 3C, an area of a region L1 where adjacent light fluxes 22 overlap each other on the incident surface 20 of the condensing optical system 12 is S1, and an irradiation area of the light flux 22 on the incident surface 20 of the condensing optical system 12 is set. When the area of L2 is S2, the value of S1/S2 is preferably 20% or more and 70% or less, and more preferably 30% or more and 50% or less. The same applies to the overlapping of the other adjacent ray bundles 22.

Therefore, the light flux emitted from the condensing optical system 12 in which the unevenness of the angular distribution is suppressed is incident on the incident surface 14 of the optical waveguide 13, and the circumferential distribution around the optical axis 15 is made uniform. The light is emitted from the emission surface 16.

Further, in the example shown in FIG. 3A, regarding the light collection optical system 12 with respect to the light bundle 22 on the incident surface 20, the number of light bundle groups arranged at the same distance from the optical axis 15 is the light bundle close to the optical axis. In order from the group, the number belonging to the first ray bundle group having the first radius R1 is 4, the number belonging to the second ray bundle group having the second radius R2 is 3, and the number belonging to the third ray bundle group having the third radius R3. Is 2, and the number belonging to the fourth ray bundle group having the fourth radius R4 is 1.

That is, the numbers belonging to the bundle of light rays having the same distance from the optical axis 15 gradually decrease as the distance from the optical axis 15 increases. Therefore, the light emitted from the emission surface 16 of the optical waveguide 13 exhibits an angular distribution in which the light intensity gradually decreases as the emission angle θ2 increases. Thereby, as illustrated in FIG. 10, it is possible to obtain an angular distribution close to the angular distribution when the light source device is a discharge lamp.

In the first embodiment, up to the fourth ray bundle group is configured, but the ray bundle groups are the first ray bundle group, the second ray bundle group, and the third ray bundle in order from the ray bundle closest to the optical axis 15. A bundle group,..., An n-th ray bundle group,. Further, in this configuration, the number of light ray bundles belonging to the light ray bundle group may gradually decrease with distance from the optical axis 15 with reference to the nth light ray bundle group whose distance from the optical axis 15 is the nth closest. Absent. As described above, n is an arbitrary natural number.

[Second embodiment]
The configuration of the second embodiment of the exposure light source device of the present invention will be described focusing on the points different from the first embodiment.

FIG. 4A is a drawing schematically showing a configuration example of another embodiment of the exposure light source device. In the embodiment shown in FIG. 4A, a bundle of rays 22 that enters the entrance surface 20 of the condensing optical system 12 is a bundle of rays 22p that enters the positive direction side of the optical axis 15 in the Y direction, and a bundle of rays 22 that enters the negative direction side. It is divided into a light beam bundle 22m that The bundle of light rays (22p, 22m) traveling in a direction not parallel to the optical axis 15 is converted by the mirror 40 into a bundle of light rays (22p, 22m) traveling in a direction parallel to the optical axis 15 and collected. It is incident on the incident surface 20 of the optical optical system 12.

As shown in FIG. 4A, in the second embodiment, the semiconductor laser light source 10p related to the light beam bundle 22p and the collimating optical system 11p are arranged in the positive direction with respect to the optical axis 15 in the Y direction, and the semiconductor laser light source 10m related to the light beam bundle 22m. The collimating optical system 11m is arranged on a plane facing each other in the negative direction with respect to the optical axis 15 in the Y direction. The semiconductor laser light sources (10p, 10m) and the collimating optical systems (11p, 11m) do not have to be arranged on the same plane.

FIG. 4B is a schematic view of the condensing optical system of FIG. 4A when viewed from the incident surface side in the Z direction. The bundle of rays (22p, 22m) that has become a light traveling parallel to the optical axis 15 by the mirror 40 is incident on the incident surface 20 of the condensing optical system 12. As shown in FIG. 4B, when the light ray bundles (22p, 22m) are rotated about the optical axis 15 on the entrance surface 20 of the condensing optical system 12 and aligned in the same radial direction 30, , Are arranged so that adjacent light beam bundles partially overlap with each other.

Also in the second embodiment, regarding the bundle of rays 22 on the entrance surface 20 through the condensing optical system 12, the number of bundles of rays arranged at the same distance from the optical axis 15 has the center at the optical axis 15. A certain ray bundle 22 is 1, the number of which belongs to the first ray bundle group of the first radius R1 is 4, the number of which belongs to the second ray bundle group of the second radius R2 is 3, and the third in the order of being closest to the optical axis. The number belonging to the third ray bundle group having the radius R3 is 2, and the number belonging to the fourth ray bundle group having the fourth radius R4 is 1.

That is, the numbers belonging to the bundle of light rays having the same distance from the optical axis 15 gradually decrease as the distance from the optical axis 15 increases. Therefore, the light emitted from the emission surface 16 of the optical waveguide 13 exhibits an angular distribution in which the light intensity gradually decreases as the emission angle θ2 increases. Thereby, as illustrated in FIG. 10, it is possible to obtain an angular distribution close to the angular distribution when the light source device is a discharge lamp.

The exposure light source device 1 that emits light having an angle distribution close to that of the light emitted from the light source device using the discharge lamp as described above can be used as a light source of the exposure device as follows.

FIG. 6 is a drawing schematically showing the configuration of the exposure apparatus 70. The exposure apparatus 70 shown in FIG. 6 includes the exposure light source device 1 of the first embodiment described above, but may include the exposure light source device 1 of the second embodiment. Then, an integrator optical system 71, a projection optical system 72, and a mask 73 that make the position distribution uniform are provided at the subsequent stage of the optical waveguide 13, and a projection lens 74 is provided as necessary. A mask 73 is installed at a position where it is projected by the projection optical system 72, and a photosensitive substrate 75, which is a target for printing a pattern image of the mask 73, is installed at a subsequent stage of the mask 73. As the integrator optical system 71, for example, an optical system such as a rod integrator or a fly's eye lens that emits light with improved uniformity of position distribution of incident light is used.

In this state, when light is emitted from the optical waveguide 13, the integrator optical system 71 makes the position distribution uniform and irradiates the projection optical system 72. The projection optical system 72 projects this light onto the photosensitive substrate 75 either directly or via the projection lens 74 as a pattern image of the mask 73.

The exposure apparatus 70 includes the exposure light source device 1 described in each of the above-described embodiments, and thus uses the semiconductor laser light source to expose the light emitted from the light source device using the discharge lamp, which is close to the angular distribution of the light. be able to.

[Another embodiment]
Hereinafter, another embodiment will be described.

<1> FIG. 5 is a drawing schematically showing a configuration example of another embodiment of the exposure light source device. As shown in FIG. 5, on the entrance surface 20 of the condensing optical system 12, the major axis 22L of the bundle of rays 22 having an elliptical shape has an elliptical shape facing the optical axis 15 side.

According to such a configuration, as described above, on the incident surface 20 of the condensing optical system 12, each light beam bundle 22 is arranged so as to be along the radial direction 30 when rotated about the optical axis 15. Since the major axis 22L directions are aligned, adjacent ray bundles 22 are likely to overlap with each other, and the adjacent ray bundles 22 can be separated from each other as compared with the case where they are aligned in the minor axis 22S direction. Therefore, the adjacent semiconductor laser light sources 10 and the adjacent collimating optical system 11 as shown in FIG. 1 can be arranged more sparsely. If the semiconductor laser light source 10 and the collimating optical system 11 can be arranged sparsely, the degree of freedom of each arrangement can be increased, and a configuration in which wiring is easier can be adopted.

<2> As shown in FIG. 4A, the configuration of the present invention is such that when the light is incident on the entrance surface 20 of the condensing optical system 12 when they are rotated about the optical axis 15 and aligned in the same radial direction 30, they are adjacent to each other. The number of ray bundles 22 that belong to the ray bundle group having the same distance from the optical axis 15 and the number of ray bundles that belong to the same distance from the optical axis 15 are The distance between the semiconductor laser light source 10 and the collimating optical system 11 is not limited to that in the above embodiment, as long as the distance from the optical axis 15 is reduced.

For example, one embodiment of the exposure light source device may include an optical fiber into which the light beam bundle 22 emitted from the semiconductor laser light source 10 and converted into substantially parallel light by the collimating optical system 11 is incident. The light beam bundles 22 incident on the condensing optical system 12 are adjacent to each other on the incident surface 20 of the condensing optical system 12 when they are rotated around the optical axis 15 and aligned in the same radial direction 30. The light emitting surface of the optical fiber is arranged such that the number of light beam bundles 22 that overlap each other and belong to the light beam bundle group having the same distance from the optical axis 15 gradually decreases as the distance from the optical axis 15 increases. May be.

<3> In the above-described embodiment, it is assumed that the semiconductor laser chip included in the semiconductor laser light source 10 has a so-called “edge emission type” structure similar to each semiconductor laser chip 200 described with reference to FIG. 8. Explained. However, the present invention can be similarly applied even if each semiconductor laser chip has a so-called “surface emitting type” structure in which light is extracted in the stacking direction of the semiconductor layers. However, in this case, the bundle of rays incident on the entrance surface 20 of the condensing optical system 12 has a substantially perfect circular shape.

1: Light source device 10, 10p, 10m: Semiconductor laser light source 11, 11p, 11m: Collimating optical system 12: Condensing optical system 13: Optical waveguide 14: Optical waveguide incident surface 15: Optical axis 16: Optical waveguide emitting surface 20: Condensing optical system incident surface 21: Ray bundle 22, 22p, 22m: Ray bundle 22a: Chief ray 22L: Long axis of ray bundle 22S: Short axis of ray bundle 23: Ray bundle 24: Ray bundle 25: Ray bundle 30: Radial direction 40: Mirror 70: Exposure device 71: Integrator optical system 72: Projection optical system 73: Mask 74: Projection lens 75: Photosensitive substrate 100: Semiconductor laser light source 101: Collimator lens 102: Condenser lens 103: Condenser lens Incident surface 104: Rod integrator 105: Rod integrator incident surface 106: Rod integrator exit surface 110a, 110b, 110c: Chief rays 111a, 111b, 111c: Chief rays 121, 121a, 121b, 121c: Ray bundles 122a, 122b, 122c: Ray bundles 123a, 123b, 123c: Ray bundle 130: Region 140: Optical axis 150: Focus position 200: Semiconductor laser chip 201: Emitter θ1: Incident angle θ2: Exit angle α1, α2: Incident angle R1: First radius R2: Second radius R3: Third radius R4: Fourth radius L1: Irradiation overlapping area L2: Irradiation area S1, S2: Area

Claims (5)

A plurality of semiconductor laser light sources,
A plurality of collimating optical systems, which are arranged corresponding to the plurality of semiconductor laser light sources, convert the light flux emitted from the semiconductor laser light source into a substantially parallel light flux, and emit the light.
A condensing optical system that includes an incident surface on which the light flux emitted from the collimating optical system is incident, and that condenses the light flux emitted from the collimating optical system,
An optical waveguide including a circular incident surface, which is arranged at a position where a bundle of rays emitted from the condensing optical system is condensed,
The respective light fluxes emitted from the plurality of semiconductor laser light sources on the entrance surface of the condensing optical system are virtually rotated about the optical axis of the condensing optical system and are directed in the same radial direction. When arranged side by side, some of the adjacent ray bundles overlap,
In the plurality of semiconductor laser light sources, on the incident surface of the condensing optical system, the number of ray bundles belonging to the bundle of ray bundles having the same distance from the optical axis of the condensing optical system is the distance from the optical axis. An exposure light source device, wherein the light source device for exposure is arranged so as to gradually decrease with distance from the optical axis, with an n-th ray bundle group close to the n-th reference. The light source device for exposure according to claim 1, wherein the plurality of semiconductor laser light sources are arranged on the same plane. In the plurality of semiconductor laser light sources, on the incident surface of the condensing optical system, the number of ray bundles belonging to the bundle of ray bundles having the same distance from the optical axis of the condensing optical system is the distance from the optical axis. 3. The exposure light source device according to claim 1, wherein the exposure light source device is arranged so as to gradually decrease with distance from the optical axis, with the closest first bundle of rays as a reference. Each of the light fluxes emitted from the plurality of semiconductor laser light sources on the incident surface of the condensing optical system has an elliptical shape whose major axis direction faces the optical axis side of the condensing optical system. The exposure light source device according to claim 1. The light source device for exposure according to any one of claims 1 to 4, further comprising an integrator optical system that homogenizes a position distribution of a light beam emitted from the optical waveguide and emits the light beam.

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