JP6652618B2 - Illuminance ratio changing method and exposure method - Google Patents

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 step by a photolithography method, such as a printed circuit board, a semiconductor wafer, and a liquid crystal display.

In the past, contact-type exposure devices using photomasks have been widely used for circuit patterning using photolithography, so-called exposure processes, but in recent years, photomasks have been used to meet the demands for higher definition and higher density of circuits. A direct-writing type exposure apparatus that modulates light using a light modulation element such as a DMD (digital micromirror device) that does not use light and exposes the light has been used (Patent Document 1). .
However, the light source used in this direct exposure apparatus often has a single wavelength in order to enable high-definition patterning. On the other hand, some resists to be exposed have sensitivity in a wide wavelength range, and in some cases, curing is not sufficiently performed at a single wavelength, and the exposure time may be long.
Therefore, as shown in Patent Document 2, there has been proposed a light source device configured to collect light by a lens using a plurality of light sources having different wavelength characteristics.

JP 2006-267719 A JP 2012-063390 A JP-A-2004-146793 JP 2008-256765 A JP 2005-316409 A JP 2009-080364 A

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 light sources are strictly arranged in a predetermined arrangement are required, and there is a problem that the apparatus becomes complicated.
The present invention aims at overcoming such disadvantages of the prior art.

In order to achieve the above object, the present invention provides
One laser diode that emits laser light having a first wavelength characteristic;
Another laser diode that emits laser light having a second wavelength characteristic different from the first wavelength characteristic,
One first optical fiber that emits light from the one laser diode at the input end and emits light at the output end, and output light from the other laser diode enters at the input end and emits at the output end. And a second optical fiber that integrates outgoing light of the first and other first optical fibers, and an outgoing light of 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 outgoing light of the first and other first optical fibers and enter the incident end of the second optical fiber,
A third optical fiber for integrating the output light of the second optical fiber, and the output end sides of the plurality of second optical fibers of the plurality of first fiber bundles are bundled in a predetermined arrangement; A second fiber bundle that integrates outgoing light from the first optical fiber and enters the incident end of the third optical fiber;
An output unit connected to the output end of the third optical fiber and outputting to the outside;
In a light source device having a control device that controls each of the laser diodes, an illuminance ratio changing method of changing an illuminance ratio for each wavelength,
The laser diode is divided into one laser diode group having the first wavelength characteristic and another laser diode group having the second wavelength characteristic,
The control device controls lighting and non-lighting for each group to change the illuminance ratio for each wavelength.
Further, the exposure apparatus of the present invention is 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 sections each independently modulating are arranged, and exposes a photosensitive material with the modulated light. An apparatus, wherein the light source device is used, and the illuminance ratio is changed by performing the illuminance ratio changing method.

According to the illuminance ratio changing method and the exposure method of the present invention, since the light source has an exposure wavelength obtained by mixing a plurality of wavelengths, it is possible to cope with a wide range of resists. Further, it is not necessary to arrange the light sources strictly in a predetermined arrangement, and a lens array is not required, so that the apparatus can be simplified. In addition, laser diodes can be easily added, and high illuminance can be easily achieved.
Furthermore, since the control of the lighting of the laser diode is performed by providing a control device, it is possible to change the illuminance ratio for each wavelength and to provide an optimum exposure condition.

FIG. 2 is a configuration diagram showing a light source device used in the method of the embodiment of the present invention. FIG. 2 is a perspective view showing an exposure apparatus used in the method according to the embodiment of the present invention. FIG. 1 is an explanatory view schematically showing a configuration of an exposure head in an exposure apparatus used in a method according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described.
This light source device basically collects light emitted from a plurality of laser diodes of different wavelengths, introduces the light into an optical fiber, and after guiding the light individually, bundles several light beams in the middle of the optical path. The optical fiber is connected to the optical fiber with 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 laser beams of different wavelengths (wavelengths A and B). In this embodiment, three LD modules 1 of the wavelength A and one LD module 2 of the wavelength B are used. A total of 12 sets of LD modules 1 and 2 are provided, and each LD module 1 and 2 is guided to the connector 4 by the LD optical fiber 3.

Further, it is desirable that the LDs 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. I have.

  The LD of each of the LD modules 1 and 2 is controlled by the control device 99, and is configured to control its lighting, non-lighting, and its output (illuminance). 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 portion b1 is connected to each connector 4, and the outgoing light from the LDs of the LD modules 1 and 2 enters at the input end of the first optical fiber 5, and further the outgoing end thereof. Is configured to emit light. The first fiber bundle portion b1 includes the first optical fiber 5, the first connector 6, and the second optical fiber 7.

The outgoing light of the three LD modules 1 and one LD module 2 is input to the first fiber bundle part b1 and passes through the first connector 6 via the four first optical fibers 5. Thus, it is configured to be integrated on one second optical fiber 7.
The first optical fibers 5 of the LD modules 1 and 2 are bundled in a predetermined arrangement on the emission end side, 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 the light emitting area in a state where four first optical fibers 5 are bundled, and the light from the four LD modules 1 and 2 is provided as described above. Are integrated in one second optical fiber 7.
In this embodiment, three first fiber bundles 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 bundles b1. are doing.

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

  The three second optical fibers 7 are further guided to the second fiber bundle portion b2, and the emitting ends of the three optical fibers 7 are bundled in an array pattern according to the shape of a light irradiation area on the DMD 56 in the exposure head 18, which will be described later. Fiber 9 is provided.

The output end of 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, 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 device can be increased by appropriately adding laser modules 1 and 2. It is.

In the light source device A described above, the emission ends of the first optical fiber 5 and the second optical fiber 7 are bundled to combine the laser beams from the LD modules 1 and 2, so that the LD modules 1 and 2 , And the LD modules 1 and 2 can be independently arranged. Therefore, the degree of freedom in installing the LD modules 1 and 2 is improved.
Further, by controlling the number of lit LDs and outputs of the LD modules 1 and 2 by the control device 99, the illuminance ratio for each wavelength can be changed, and the necessary optimal exposure conditions can be provided.

A 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 has a base 11 that is horizontally arranged, a movable stage 13 that is slidably mounted on the base 11, and that holds a substrate 12 to be exposed by suction on a surface thereof; And an exposure unit 14 for exposing the substrate 12 held by the exposure unit 13 to light.

The substrate 12 is, for example, a printed wiring board or a glass substrate for a flat panel display having a surface coated or adhered with a photosensitive material. The digital exposure apparatus B exposes the substrate 12 as described above to record, for example, a wiring pattern on a photosensitive material of the substrate 12 without a mask. In the present embodiment, the moving direction of the moving stage 13 is described as a Y direction, a direction perpendicular to the Y direction on a horizontal plane is defined as an X direction (width direction of the substrate 12), and a vertical direction perpendicular to the horizontal plane is defined as a Z direction. The base 11 is formed to be long in the Y direction.

  The base 11 is supported by legs 115 attached to each of the four corners. On the upper surface 11a of the base 11, two guide rails 16 substantially parallel to the Y direction are provided. The moving stage 13 is slidably mounted in the Y direction via the guide rails 16 on the base 11. A drive mechanism (not shown) constituted by a linear motor or the like is connected to the movement stage 13, and moves in the Y direction according to the drive of the drive mechanism.

  The exposure unit 14 is attached to the center of the base 11 in the Y direction via a pair of columns 17. Each support 17 is fixed to both ends of the base 11 in the X direction. Each support 17 holds the exposure unit 14 at a predetermined distance from the upper surface 11a of the base 11 so as to pass below the exposure unit 14 when the moving stage 13 moves in the Y direction. The exposure section 14 has 16 exposure heads 18. Each of these exposure heads 18 irradiates the substrate 12 passing therethrough with light.

  Each exposure head 18 is arranged in two rows of eight in the X direction. Each of the exposure heads 18 in the second row is moved in the X direction with respect to each of the exposure heads 18 in the first row so that the center of each is located near the center between adjacent ones of the exposure heads 18 in the first row. They are displaced by ピ ッ チ pitch. By arranging in this manner, a portion that cannot be exposed by each of the exposure heads 18 in the first row is exposed by each of the exposure heads 18 in the second row, and exposure recording is performed without any gap in the X direction of the substrate 12. 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 the frame data to each exposure head 18 via the signal cable 22. The frame data is, for example, data expressing the density of each pixel constituting an image in binary (presence or absence of dot printing).

  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 on the substrate 12 transported by the moving stage 13. Thus, 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 in parallel with the X direction so as to straddle each guide rail 16. The gate 23 is provided with three cameras 25. Each camera 25 is connected to a controller (not shown) that controls the entire digital exposure apparatus 10.

  Each camera 25 photographs the moving stage 13 passing through the gate 23 and outputs the acquired image data to the controller. The controller calculates, based on the image data acquired by each camera 25, the amount of deviation of the substrate 12 from the appropriate position on the moving stage 13 in the X direction, the Y direction, and the θ direction (rotation about the Z direction). . The calculated shift amount is input to the image processing unit 21 and used for correcting frame data. Note that 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. Further, the calculation of the shift amount may be performed 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 displacement amount can be easily calculated.

  Each length measuring device 24 is connected to the controller similarly to 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 a laser beam and receiving the reflected light. Then, 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 has been described. Any other material may be used.

Details of a connection portion between the exposure head 18 of the exposure apparatus B having the above configuration and the light source device A will be described with reference to FIG.
The exposure head 18 includes an incident optical system 40, a light modulation unit 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 arranged to face the emission end of the optical fiber 9 via the second connector 10. The incident optical system 40 includes a condenser lens 50 that collects laser light (LB: laser beam) emitted from the optical fiber 9, and a rod disposed on the optical path of the laser light LB that has passed through the condenser lens 50. Optical integrator 51, an imaging lens 52 that forms an image of the laser light LB that has passed through the optical integrator 51, and a light modulator 41 that reflects the laser light LB that is formed by the imaging lens 52. And a mirror 53 for making the light incident on the mirror 53.

  The optical integrator 51 is, for example, a light-transmitting rod formed in a quadrangular prism shape. The optical integrator 51 converts the laser beam LB traveling inside while undergoing total reflection into a light beam that is close to parallel light and has uniform intensity in a beam cross section. As a result, a high-definition image having no variation in illumination light intensity is exposed on the substrate 12. In addition, it is preferable that the incident end face and the output end face of the optical integrator 51 are coated with an anti-reflection film in order to increase the light transmittance.

  The light modulator 41 includes a TIR (total internal reflection) prism 55 and a DMD (digital micro mirror device) 56 that is a spatial light modulator. The TIR prism 55 reflects the laser light LB incident via the mirror 53 toward the DMD 56. The DMD 56 is a mirror device in which a micromirror constituting a pixel is supported on a support and is tiltably provided on a two-dimensionally arranged SRAM (Static Random Access Memory) cell.

  The DMD 56 has a state in which the irradiated laser light LB is reflected toward the first imaging optical system 42 in accordance with the digital signal written in the SRAM cell, and a state in which the irradiated laser light LB is a light absorber not shown. The inclination angle of the micromirror is changed so that the light is reflected toward the micromirror. The light modulation unit 41 controls the inclination of the micro mirror of each pixel of the DMD 56 according to the frame data input from the image processing unit 21 to generate image light corresponding to the frame data.

  The first imaging optical system 42 includes lenses 57 and 58, and enlarges the image light generated by the light modulator 41 to a predetermined magnification to form an image on the MLA 43.

  The MLA 43 is, for example, formed in a substantially rectangular flat plate shape using quartz glass. Further, the MLA 43 has a plurality of microlenses 43a two-dimensionally arranged corresponding to each pixel of the DMD 56. Each micro lens 43a is a plano-convex lens having a flat upper surface and a lower convex surface. Each micro lens 43a individually forms an image of the image light from each micro mirror of the DMD 56, and sharpens the image light enlarged by the first imaging optical system 42. The shape of each micro lens 43a is not limited to a plano-convex lens, but may be, for example, a biconvex lens.

  The APA 44 has a light-shielding property, and is provided with a plurality of apertures 44a for transmitting image light. Each aperture 44a is two-dimensionally arranged corresponding to each pixel of the DMD 56 similarly to each micro lens 43a. The APA 44 is arranged with the apertures 44a facing the microlenses 43a, and allows the image light formed by the microlenses 43a to pass through the corresponding apertures 44a. The APA 44 prevents unnecessary light generated by chattering of each micro mirror of the DMD 56 from passing through, and further improves the sharpness of an exposed 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 having passed through the APA 44 to a predetermined magnification, or makes the image light enter the prism pair 62 at the same magnification. The prism pair 62 is provided movably in the up-down direction, and adjusts the focus of the image light on the substrate 12 by moving up and down.

  Further, in the above embodiment, the DMD 56 is shown as the spatial light modulator, but the spatial light modulator is not limited to this, and may be, for example, a liquid crystal light shutter. Further, in the above embodiment, the substrate 12 on which the photosensitive material is applied or stuck is shown as the exposure target, but the exposure target is not limited to this, and may be, for example, a photographic film or a photographic paper.

DESCRIPTION OF SYMBOLS 1 LD module 2 LD module 3 LD optical fiber 4 connector 5 1st optical fiber 6 1st connector 7 2nd optical fiber 9 3rd optical fiber 10 2nd connector 12 Substrate (exposure object)
14 Exposure Unit 18 Exposure Head 19 Light Source Unit 40 Incident Optical System 41 Light Modulation Unit 42 First Imaging Optical System 43 Microlens Array 43a Microlens 44 Aperture Array 44a Aperture 45 Second Imaging Optical System (Projection Optical System)
56 DMD (Spatial Light Modulator)
99 control device b1 first fiber bundle portion b2 second fiber bundle portion A light source device B exposure device

Claims (6)

One laser diode that emits laser light having a first wavelength characteristic;
Another laser diode that emits laser light having a second wavelength characteristic different from the first wavelength characteristic,
One first optical fiber that emits light from the one laser diode at the input end and emits light at the output end, and output light from the other laser diode enters at the input end and emits at the output end. And a second optical fiber that integrates outgoing light of the first and other first optical fibers, and an outgoing light of 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 outgoing light of the first and other first optical fibers and enter the incident end of the second optical fiber,
A third optical fiber that integrates the output light of the second optical fiber, and the output end sides of the plurality of second optical fibers of the plurality of first fiber bundles are bundled in a predetermined arrangement; A second fiber bundle that integrates outgoing light and enters the incident end of the third optical fiber;
An output unit connected to the output end of the third optical fiber and outputting to the outside;
In a light source device having a control device that controls each of the laser diodes, an illuminance ratio changing method of changing an illuminance ratio for each wavelength,
The laser diode is divided into one laser diode group having the first wavelength characteristic and another laser diode group having the second wavelength characteristic,
An illuminance ratio changing method, wherein the illuminance ratio for each wavelength is changed by controlling lighting and non-lighting for each group using the control device.   The illuminance ratio changing method according to claim 1, wherein the emission wavelength of each of the laser diodes in the first wavelength characteristic and the second wavelength characteristic is included in a wavelength range of 190 nm to 530 nm.   3. The illuminance ratio changing method according to claim 2, wherein the one laser diode has a wavelength characteristic having a peak near 375 nm, and the other laser diode has a wavelength characteristic having a peak near 405 nm. An exposure method using an exposure device that modulates light emitted from a light source device with a spatial light modulation element in which a number of pixel portions that independently modulate are arranged, and exposes a photosensitive material with the modulated light. hand,
The exposure device is
One laser diode that emits laser light having a first wavelength characteristic;
Another laser diode that emits laser light having a second wavelength characteristic different from the first wavelength characteristic,
One first optical fiber that emits light from the one laser diode at the input end and emits light at the output end, and output light from the other laser diode enters at the input end and emits at the output end. And a second optical fiber that integrates outgoing light of the first and other first optical fibers, and an outgoing light of 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 outgoing light of the first and other first optical fibers and enter the incident end of the second optical fiber,
A third optical fiber that integrates the output light of the second optical fiber, and the output end sides of the plurality of second optical fibers of the plurality of first fiber bundles are bundled in a predetermined arrangement; A second fiber bundle that integrates outgoing light and enters the incident end of the third optical fiber;
An output unit connected to the output end of the third optical fiber and outputting to the outside;
A light source device having a control device for controlling each of the laser diodes,
An exposure method, wherein the illuminance ratio is changed by performing the illuminance ratio changing method according to any one of claims 1 to 3.   The exposure apparatus includes a microlens array in which a large number of microlenses for individually condensing a large number of light beams modulated by the large number of pixel units are arranged, and exposure is performed using this exposure apparatus. The exposure method according to claim 4, wherein the exposure is performed.   The illuminance ratio changing method according to claim 1, wherein the light source device is for direct drawing in which light is exposed by modulating light using a light modulation element.

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