JP2016035509A - Light source device and exposure apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device that uses a plurality of light sources with different wavelengths and does not require a strict disposition of the light sources in a predetermined arrangement.SOLUTION: A plurality of LD modules 1, 2 each include a single LD (laser diode) and a condenser lens and emit a laser beam at a different wavelength. The LD of each LD module 1, 2 is controlled by a controller 99 and is controlled for operations of lighting and non-lighting and an output (illuminance) thereof. Exiting light beams from the three LD modules 1 and the one LD module 2 are input to a first fiber bundle b1 and integrated into one second optical fiber 7 through four first optical fibers 5 and a first connector 6. The three second optical fibers 7 are further guided to a second fiber bundle b2; and fibers at an exit end side of the second fiber bundle are bundled in an arrangement pattern corresponding to a shape of an illumination region to a DMD 56 in an exposure head 18 and are connected to a third optical fiber 9, which is connected to an incident optical system 40 via a second connector 10 so as to guide the laser beam to the exposure head 18 of an exposure apparatus B.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light source device and an exposure apparatus suitable for use in a direct drawing method used in an exposure process by a photolithography method such as a printed board, a semiconductor wafer, and a liquid crystal display.

Conventionally, a contact type exposure apparatus using a photomask has been widely used for circuit patterning using a photolithography method, that is, a so-called exposure process. However, in recent years, in order to meet the high definition and high density of a circuit, a photomask is used. A direct-drawing type exposure apparatus that uses light modulation elements such as DMD (digital micro mirror device) that is not used to modulate and expose light has been used (Patent Document 1). .
However, the light source used in this direct drawing type exposure apparatus is often a single wavelength in order to enable high-definition patterning. On the other hand, some exposed resists have a sensitivity in a wide wavelength range, and there are cases where a single wavelength does not sufficiently cure or the exposure time becomes long.
Therefore, as shown in Patent Document 2, a light source device having a configuration in which light is condensed by a lens using a plurality of light sources having different wavelength characteristics has been proposed.

JP 2006-267719 A JP2012-063390

However, in the case of a configuration using a plurality of light sources and lenses having different wavelengths, a light source array and a lens array in which the light sources are strictly arranged in a predetermined arrangement are required, and there is a problem that the apparatus becomes complicated.
The object of the present invention is to overcome the drawbacks of the prior art.

In order to achieve the above object, the present invention provides one laser diode that emits laser light having a predetermined wavelength characteristic, and another laser that emits laser light having another wavelength characteristic different from the predetermined wavelength characteristic. A diode, one first optical fiber that receives light emitted from the first laser diode at the incident end and emits the light at the output end, and light emitted from the other laser diode is incident at the incident end and is emitted. A first optical fiber that emits light and a second optical fiber that integrates the light emitted from the first and other first optical fibers, the first optical fiber and the other first light. A plurality of first fiber bundles that bundle the emission end sides of the fibers in a predetermined arrangement, integrate the emission lights of the first and other first optical fibers, and enter the incident ends of the second optical fibers; and 3rd which integrates the emitted light of the 2nd optical fiber A plurality of first optical fiber bundle portions, the output end sides of the plurality of second optical fibers are bundled in a predetermined arrangement, and the output light of each second optical fiber is integrated to enter the third optical fiber. It has a 2nd fiber bundle made to enter into an end, and an output part for connecting with the output end of the 3rd optical fiber, and outputting outside.
It is desirable that the laser diode includes a control device that individually performs at least one of lighting / non-lighting control and output control. The laser diode preferably includes a control device that performs at least one of lighting / non-lighting control and output control for each predetermined group.
Further, the exposure apparatus of the present invention modulates the light emitted from the light source device by a spatial light modulation element in which a large number of pixel units each independently modulated is arranged, and exposes the photosensitive material with the modulated light. It is an apparatus, Comprising: The said light source device is used, It is characterized by the above-mentioned.

According to the light source device and the exposure apparatus of the present invention, it becomes a light source having an exposure wavelength obtained by mixing a plurality of wavelengths, so that it can cope with a wide range of resists. Further, it is not necessary to strictly arrange the light sources in a predetermined arrangement, and no lens array is required, so that the apparatus can be simplified. In addition, laser diodes can be easily added and high illuminance can be easily achieved.
Furthermore, if a control device is provided to control the lighting of the laser diode and the output control, the illuminance ratio for each wavelength can be changed, and an optimum exposure condition can be provided.

The block diagram which shows one Embodiment of the light source device of this invention. The perspective view which shows one Embodiment of the exposure apparatus of this invention. Explanatory drawing which shows schematically the structure of the exposure head in one Embodiment of the exposure apparatus of this invention.

Embodiments of the present invention will be described below.
This light source device basically collects light emitted from a plurality of laser diodes of different wavelengths, introduces them into an optical fiber, bundles them in the middle of the optical path, and bundles them several times. The optical fiber is connected by a connector and mixed.

This will be described in detail below with reference to FIGS.
As shown in FIG. 1, the light source device A includes a plurality of LD modules 1 and 2. Each of the LD modules 1 and 2 includes one laser diode (LD) and a condenser lens. The LD module 1 and the LD module 2 include LDs that emit lasers having different wavelengths (wavelength A and wavelength B). In this embodiment, three LD modules 1 having a wavelength A and one LD module 2 having a wavelength B are provided. Each group includes a total of 3 sets and 12 LD modules 1 and 2, and each LD module 1 and 2 is led to a connector 4 by an LD optical fiber 3.

Further, it is desirable that the LD wavelengths of the LD modules 1 and 2 have wavelength characteristics in the range of 190 to 530 nm.
In this embodiment, the wavelength A of the LD of the LD module 1 has a wavelength characteristic having a peak near 375 nm, and the wavelength B of the LD of the LD module 2 has a wavelength characteristic having a peak near 405 nm. Yes.

  The LD of each of the LD modules 1 and 2 is controlled by the control device 99, and is configured to control lighting, non-lighting, and output (illuminance) thereof. Each LD of the LD modules 1 and 2 may be configured to be individually controlled by the control device 99, or may be configured to be controlled for each group.

  The first optical fiber 5 of the first fiber bundle part b1 is connected to each connector 4, and the outgoing light from the LD of the LD modules 1 and 2 is incident on the incident end of the first optical fiber 5, and further the outgoing end thereof. It is comprised so that it may radiate | emit with. The first fiber bundle portion b1 includes the first optical fiber 5, the first connector 6, and the second optical fiber 7.

Light emitted from the three LD modules 1 and one LD module 2 is input to the first fiber bundle portion b1 and passes through the first connector 6 via the four first optical fibers 5. Thus, it is configured to be integrated in one second optical fiber 7.
The output ends of the first optical fibers 5 of the LD modules 1 and 2 are bundled in a predetermined arrangement, and are connected to one second optical fiber 7 via the first connector 6.

The second optical fiber 7 has a core having a size equal to or larger than that of the light emitting region in a state where the four first optical fibers 5 are bundled. As described above, the light from the four LD modules 1 and 2 is used. Are integrated into one second optical fiber 7.
In this embodiment, three first fiber bundle portions b1 are provided, and a total of 12 LD modules 1 and 2 are integrated into three second optical fibers 7 in the three first fiber bundle portions b1. doing.

  The second optical fiber 7 is a multi-mode optical fiber, and is configured to be uniformed by interference of light in the fiber and interaction between modes.

  The three second optical fibers 7 are further guided to the second fiber bundle portion b2, and the emission end side thereof is bundled in an array pattern corresponding to the shape of the light irradiation region to the DMD 56 in the exposure head 18 to be described later. Fiber 9 is formed.

The third optical fiber 9 in which the three second optical fibers 7 are bundled is connected to the incident optical system 40 via the second connector 10 at the emission end side, and the laser light is guided to the exposure head 18 of the exposure apparatus B. It is configured as follows.
In the above embodiment, an example in which laser beams of two types of wavelengths are used is shown. However, a plurality of wavelengths may be used, and the output of the apparatus can be increased by adding laser modules 1 and 2 as appropriate. It is.

Since the light source device A described above bundles the emission end sides of the first optical fiber 5 and the second optical fiber 7 and combines the laser beams from the LD modules 1 and 2, the LD modules 1 and 2 are predetermined. The LD modules 1 and 2 can be arranged independently of each other. Therefore, the degree of freedom of installation of the LD modules 1 and 2 is improved.
Further, by controlling the number and output of the LDs of the LD modules 1 and 2 by the control device 99, the illuminance ratio for each wavelength can be changed, and the necessary optimum exposure conditions can be provided.

The configuration of a digital exposure apparatus (image exposure apparatus) B using the light source apparatus A will be described with reference to FIG.
The exposure apparatus B is formed in a substantially rectangular flat plate, and a base 11 that is horizontally disposed, a movable stage 13 that is slidably attached to the base 11 and holds the substrate 12 to be exposed on the surface, and the movable stage. And an exposure unit 14 that performs exposure on the substrate 12 held on the substrate 13.

The substrate 12 is, for example, a printed wiring board or a glass panel for flat panel display on which a photosensitive material is applied or stuck. The digital exposure apparatus B records the wiring pattern or the like on the photosensitive material of the substrate 12 without masking by exposing the substrate 12 as described above. In the present embodiment, the moving direction of the moving stage 13 is described as the Y direction, the direction orthogonal to the Y direction on the horizontal plane is set as the X direction (width direction of the substrate 12), and the vertical direction orthogonal to the horizontal plane is described as the Z direction. The base 11 is formed long in the Y direction.

  The base 11 is supported by legs 115 attached to the four corners. Two guide rails 16 substantially parallel to the Y direction are provided on the upper surface 11 a of the base 11. The movable stage 13 is attached to the base 11 through these guide rails 16 so as to be slidable in the Y direction. The moving stage 13 is connected to a driving mechanism (not shown) constituted by a linear motor or the like, and moves in the Y direction according to the driving of the driving mechanism.

  The exposure unit 14 is attached to the center of the base 11 in the Y direction via a pair of support columns 17. Each column 17 is fixed to both ends of the base 11 in the X direction. Each support column 17 holds the exposure unit 14 at a predetermined distance from the upper surface 11a of the base 11 so that it passes under the exposure unit 14 when the movable stage 13 moves in the Y direction. The exposure unit 14 has 16 exposure heads 18. Each of these exposure heads 18 irradiates light to the substrate 12 passing thereunder.

  Each exposure head 18 is arranged in two rows of eight in the X direction. The exposure heads 18 in the second row are arranged in the X direction with respect to the exposure heads 18 in the first row so that their centers are located near the centers of the adjacent ones of the exposure heads 18 in the first row. They are shifted by 1/2 pitch. By disposing in this way, the portion that cannot be exposed by each exposure head 18 in the first row is exposed by each exposure head 18 in the second row, and exposure recording is performed in the X direction of the substrate 12 without any gap. Note that the number and arrangement of the exposure heads 18 provided in the exposure unit 14 may be appropriately changed according to the size of the substrate 12 and the like.

  Image data (image information) corresponding to a wiring pattern or the like recorded on the substrate 12 is input to the image processing unit 21. The image processing unit 21 creates frame data for each exposure head 18 based on the input image data. Then, the image processing unit 21 inputs frame data to each exposure head 18 via the signal cable 22. The frame data is, for example, data representing the density of each pixel constituting the image with binary values (whether or not dots are recorded).

  Each exposure head 18 modulates the laser light incident from the light source device A based on the frame data, and projects the modulated light onto the substrate 12 conveyed by the moving stage 13. As a result, an image corresponding to the image data input to the image processing unit 21 is exposed and recorded on the substrate 12.

  The base 11 is further provided with a gate 23 formed in a substantially U-shape and a pair of length measuring devices 24 attached to one end in the Y direction. The gate 23 is attached to the base 11 substantially parallel to the X direction so as to straddle each guide rail 16. Three cameras 25 are attached to the gate 23. Each camera 25 is connected to a controller (not shown) that comprehensively controls the entire digital exposure apparatus 10.

  Each camera 25 images the moving stage 13 that passes through the gate 23 and outputs the acquired image data to the controller. Based on the image data acquired by each camera 25, the controller calculates the amount of deviation in the X direction, Y direction, and θ direction (rotation about the Z direction) of the substrate 12 with respect to the appropriate position on the moving stage 13. . The calculated shift amount is input to the image processing unit 21 and used for correcting the frame data. The number of cameras 25, the arrangement interval, and the like may be appropriately changed according to the size of the substrate 12 and the like. The amount of deviation may be calculated by well-known image processing. At this time, it is preferable to provide an alignment mark or the like on the substrate 12 so that the amount of deviation can be easily calculated.

  Each length measuring device 24 is connected to the controller in the same manner as each camera 25. Each length measuring device 24 measures the position of the moving stage 13 by irradiating the side end surface of the moving stage 13 with laser light and receiving the reflected light. Each length measuring device 24 outputs the measured position of the moving stage 13 to the controller. In the present embodiment, the so-called laser interference type length measuring device 24 is shown. However, the present invention is not limited to this, and any device that can measure the position of the moving stage 13 such as one using an ultrasonic wave or a stereo camera is used. Any other one may be used.

Details of the connecting portion between the exposure head 18 and the light source device A of the exposure apparatus B configured as described above will be described with reference to FIG.
The exposure head 18 includes an incident optical system 40, a light modulator 41, a first imaging optical system 42, a micro lens array (MLA) 43, an aperture array (APA) 44, A second imaging optical system (projection optical system) 45. The incident optical system 40 is disposed so as to face the emission end of the optical fiber 9 via the second connector 10. The incident optical system 40 includes a condensing lens 50 that condenses a laser beam (LB) emitted from the optical fiber 9, and a rod disposed on the optical path of the laser light LB that has passed through the condensing lens 50. Optical integrator 51, imaging lens 52 that forms an image of laser light LB that has passed through optical integrator 51, and laser light LB imaged by imaging lens 52 is reflected to modulate light modulator 41. And a mirror 53 to be incident on the mirror.

  The optical integrator 51 is, for example, a translucent rod formed in a quadrangular prism shape. The optical integrator 51 converts the laser beam LB traveling inside while being totally reflected into a light beam that is close to parallel light and has a uniform beam cross-sectional intensity. As a result, a high-definition image without variations in illumination light intensity is exposed on the substrate 12. In addition, it is preferable to coat an antireflection film on the incident end face and the outgoing end face of the optical integrator 51 in order to increase the light transmittance.

  The light modulation unit 41 includes a TIR (total internal reflection) prism 55 and a DMD (digital micro mirror device) 56 which is a spatial light modulation element. The TIR prism 55 reflects the laser beam LB incident through the mirror 53 toward the DMD 56. The DMD 56 is a mirror device in which a micromirror that constitutes a pixel is supported on a column and tilted on a two-dimensionally arranged SRAM (Static Random Access Memory) cell.

  The DMD 56 is a light absorber in which the irradiated laser light LB is reflected toward the first imaging optical system 42 according to the digital signal written in the SRAM cell, and the irradiated laser light LB is not shown. The tilt angle of the micromirror is changed to the state of reflecting toward the screen. The light modulation unit 41 generates image light corresponding to the frame data by controlling the inclination of the micromirror of each pixel of the DMD 56 according to the frame data input from the image processing unit 21.

  The first image-forming optical system 42 includes lenses 57 and 58 and enlarges the image light generated by the light modulation unit 41 to a predetermined magnification and forms an image on the MLA 43.

  The MLA 43 is formed in a substantially rectangular flat plate shape by, for example, quartz glass. In addition, the MLA 43 is formed with a plurality of microlenses 43 a that are two-dimensionally arranged corresponding to the pixels of the DMD 56. Each micro lens 43a is a plano-convex lens having a flat upper surface and a convex lower surface. Each micro lens 43a individually forms image light from each micro mirror of the DMD 56, and sharpens the image light enlarged by the first image forming optical system 42. In addition, the shape of each micro lens 43a is not restricted to a plano-convex lens, For example, a biconvex lens etc. may be sufficient.

  The APA 44 has a light shielding property, and a plurality of apertures 44a for allowing image light to pass therethrough are formed. Each aperture 44a is two-dimensionally arranged corresponding to each pixel of the DMD 56, like each microlens 43a. The APA 44 is arranged with each aperture 44a facing each micro lens 43a, and the image light imaged by each micro lens 43a passes through each corresponding aperture 44a individually. The APA 44 prevents unnecessary light caused by chattering of each micromirror of the DMD 56 from passing, and further improves the sharpness of the exposure image.

  The second imaging optical system 45 includes lenses 60 and 61 and a prism pair 62, and projects image light that has passed through the APA 44 onto the substrate 12. Each of the lenses 60 and 61 enlarges the image light that has passed through the APA 44 to a predetermined magnification or makes it incident on the prism pair 62 at an equal magnification. The prism pair 62 is provided so as to be movable in the vertical direction, and adjusts the focus of the image light on the substrate 12 by moving up and down.

  In the above embodiment, the DMD 56 is shown as the spatial light modulation element. However, the spatial light modulation element is not limited to this, and may be, for example, a liquid crystal light shutter. Furthermore, in the above-described embodiment, the substrate 12 on which a photosensitive material is applied or stuck is shown as an exposure target. However, the exposure target is not limited to this, and may be, for example, a photographic film or a photographic paper.

  1: LD module, 2: LD module, 3: LD optical fiber, 4: connector, 5: first optical fiber, 6: first connector, 7: second optical fiber, 9: third optical fiber, 10: first 2 connectors, 12: substrate (exposure target), 14: exposure unit, 18: exposure head, 19: light source unit, 40: incident optical system, 41: light modulation unit, 42: first imaging optical system, 43: micro Lens array, 43a: Micro lens, 44: Aperture array, 44a: Aperture, 45: Second imaging optical system (projection optical system), 56: DMD (spatial light modulation element), 99: Control device, b1: First Fiber bundle portion, b2: second fiber bundle portion, A: light source device, B: exposure device B.

Claims (7)

One laser diode emitting laser light having a predetermined wavelength characteristic;
Other laser diodes that emit laser light having other wavelength characteristics different from the predetermined wavelength characteristics;
Light emitted from the first laser diode is incident at the incident end and emitted from the outgoing end, and light emitted from the other laser diode is incident at the incident end and emitted from the outgoing end. Another first optical fiber, and a second optical fiber that integrates the light emitted from the first and other first optical fibers, and the light emitted from the first first optical fiber and the other first optical fiber. A plurality of first fiber bundles that bundle the end sides in a predetermined arrangement, integrate the emitted light of the first optical fiber and the other first optical fiber, and enter the incident end of the second optical fiber;
Each of the second optical fibers includes a third optical fiber that integrates the light emitted from the second optical fiber, the output end sides of the plurality of second optical fibers of the plurality of first fiber bundle portions being bundled in a predetermined arrangement. A second fiber bundle that integrates the emitted light and enters the incident end of the third optical fiber;
An output unit for connecting to an output end of the third optical fiber and outputting the output to the outside;
A light source device comprising:   The light source device according to claim 1, wherein the laser diode includes a control device that individually performs at least one of lighting / non-lighting control and output control.   The light source device according to claim 1, wherein the laser diode includes a control device that performs at least one of lighting / non-lighting control and output control for each predetermined group. The laser diode has a wavelength characteristic included in a wavelength region of 190 nm to 530 nm.
The light source device according to claim 1. The one laser diode has a wavelength characteristic having a peak around 375 nm, and the other laser diode has a wavelength characteristic having a peak around 405 nm.
The light source device according to claim 1. An exposure apparatus that modulates light emitted from a light source device by a spatial light modulation element in which a large number of pixel units that are independently modulated are arranged, and exposes a photosensitive material with the modulated light,
An exposure apparatus using the light source device according to claim 1. A microlens array in which a large number of microlenses that individually collect a large number of light beams modulated by the large number of pixel units are arranged;
The exposure apparatus according to claim 6.

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