JP5142217B2 - Exposure equipment - Google Patents

Description

  The present invention relates to an exposure apparatus used in a manufacturing process of a semiconductor, a liquid crystal substrate, and a color filter.

  In recent years, in the manufacturing process of semiconductors, liquid crystal substrates, and color filters, the use of ultraviolet discharge lamps with large input power has shortened processing time and batch exposure of large-area workpieces. It has been. Accordingly, high-pressure discharge lamps, which are ultraviolet discharge lamps, are required to emit light with higher brightness. However, if the input power to the high-pressure discharge lamp is simply increased, the load on the electrode arranged inside the discharge vessel increases, and the inside of the high-pressure discharge lamp becomes black due to the evaporation from the electrode, There is a problem of causing a short life.

FIG. 12 is a view showing a semiconductor exposure apparatus described in Patent Document 1 according to the prior art.
As shown in the figure, this semiconductor exposure apparatus is an apparatus that irradiates a laser beam to an electrodeless discharge lamp and irradiates an irradiated object with ultraviolet light from the electrodeless discharge lamp by laser excitation. The semiconductor exposure apparatus 100 includes a laser oscillator 101, optical components 103 and 104 that adjust the laser beam emitted from the laser oscillator 101 to a desired beam diameter, and a condensing lens 105 that collects the laser beam emitted from the optical component 104. The electrodeless discharge lamp 106 that receives the laser beam condensed by the condenser lens 105, the elliptical reflector 107 that reflects the ultraviolet light emitted from the electrodeless discharge lamp 106, and the ultraviolet light reflected by the elliptical reflector 107 It comprises an optical system 111 for irradiating a semiconductor wafer 110 that is an object to be irradiated. The elliptical reflecting mirror 107 has a light taking-in hole 108 for entering the laser beam and a light extraction for radiating the laser beam transmitted without being absorbed in the electrodeless discharge lamp 106 to the outside of the elliptical reflecting mirror 107. A hole 109 is provided, and the laser beam emitted from the light extraction hole 109 is absorbed by the light absorption plate 112 and converted into heat, for example, so that the laser beam does not return to the electrodeless discharge lamp 106. Yes. According to this semiconductor exposure apparatus 100, since there is no electrode in the discharge lamp 106, the above problem that the electrode evaporates and the inside of the discharge vessel becomes black and the life of the lamp is shortened while the lamp is lit is solved. Can do.

Further, Patent Document 2 relating to another prior art discloses a light source device that makes a laser beam incident on an electrodeless discharge lamp from the top side of a parabolic reflector, and an electrodeless discharge in which a discharge vessel also serves as a parabolic reflector. There are disclosed light source devices in which a laser beam is incident from the opening side of a parabolic reflecting mirror of the lamp, and even in these light source devices, since there is no electrode in the discharge lamp, the electrode evaporates and discharges when the lamp is turned on. The problem of blackening the inside of the container and shortening the lamp life can be solved.
JP-A-61-193385 US 2007/0228300

  However, in the exposure apparatus described in Patent Document 1, a light intake hole 108 and a light extraction hole 109 are provided on the side surface of the elliptical reflecting mirror 107 for supplying energy to the electrodeless discharge lamp 106, and the light intake hole 108 is interposed. The laser beam is incident on the electrodeless discharge lamp 106. Because of the light intake hole 108 and the light extraction hole 109, the ultraviolet light emitted from the electrodeless discharge lamp cannot be extracted efficiently. When a laser beam capturing hole 108 is provided in the elliptical reflecting mirror 107 and the laser beam is incident on the electrodeless discharge lamp 106 from a direction substantially orthogonal to the optical axis of the elliptical reflecting mirror 107, the plasma formed by the laser beam The shape is an elongated shape extending in the direction along the incident direction of the laser beam. In this case, the plasma formed in an elongated shape extending in the direction intersecting the optical axis of the elliptical reflecting mirror 107 is collected by the elliptical reflecting mirror 107, and cannot be efficiently collected on the exposure surface. There is.

  In addition, when the light source device described in Patent Document 2 is applied to an exposure apparatus and when a laser beam is incident from the top side of a parabolic reflector, the laser beam that is not absorbed by the discharge vessel is reflected by a parabolic reflection. There is a problem in that unnecessary light comes out on the exposure surface because it is emitted toward the front surface from the opening side of the mirror.

  Further, when the configurations of Patent Document 1 and Patent Document 2 are applied to an actual exposure apparatus, the intensity distribution of the incident laser beam generally has a portion with the highest light intensity in the central portion such as a Gaussian distribution. Therefore, the part with the highest light intensity hits the discharge vessel or the sealing tube part of the lamp, and the laser beam cannot be collected efficiently, that is, the energy of the laser beam is sufficiently introduced into the discharge part in the discharge vessel. There is a problem that can not be.

  In order to solve this problem, when the laser beam incident on the exposure apparatus is focused on the discharge lamp, avoiding the sealing tube portion of the discharge lamp, the energy density of the laser beam increases, and a hole is formed in the discharge vessel. It is conceivable that the optical element arranged in the exposure apparatus, such as opening, may cause problems such as damage to the optical element.

  In view of the above problems, an object of the present invention is to provide a laser irradiation optical system capable of sufficiently introducing the energy of a laser beam into a discharge part in a discharge vessel and preventing damage to an optical element. Another object of the present invention is to provide an exposure apparatus.

The present invention employs the following means in order to solve the above problems.
The first means includes a discharge lamp, an elliptical reflecting mirror that reflects ultraviolet light emitted from the discharge lamp, an exposure optical system that irradiates an irradiated object with ultraviolet light reflected by the elliptical reflecting mirror, and An exposure apparatus having a laser oscillator for entering a laser beam for supplying energy to a discharge lamp, wherein the laser oscillator and a laser beam from the laser oscillator are branched to emit a plurality of laser beams A beam branching unit is disposed outside the exposure optical system, and an optical member having a wavelength selection function for introducing the laser beam is disposed on the optical path of the ultraviolet light reflected by the elliptical reflecting mirror; The plurality of laser beams branched at the branching portion avoid the reflected light inhibition region of the ultraviolet light that is reflected by the elliptical reflector that exists in the optical path of the elliptical reflector via the optical member. Wherein the elliptical reflective mirror is incident from an opening side of the elliptical reflector, an exposure apparatus characterized by being incident on the discharge lamp.
A second means is the first means, wherein the discharge lamp includes a pair of electrodes disposed opposite to each other on the optical axis of the elliptical reflecting mirror in the discharge container, and the discharge container connected in a direction opposite to each other. An exposure apparatus comprising a pair of sealing portions extending and disposed on an optical axis of the elliptical reflecting mirror.
A third means is an exposure apparatus according to the first means or the second means, wherein the beam branching section includes at least a beam splitter and a plane reflecting mirror.
A fourth means is an exposure apparatus according to the first means or the second means, wherein the beam branching section includes at least a beam splitter and a plurality of parabolic reflectors.
According to a fifth means, in any one of the first to fourth means, the exposure optical system includes a collimator lens and an integrator lens, and the optical member includes the collimator lens and the integrator lens. The exposure apparatus is arranged between the two.
A sixth means is any one of the first means to the fifth means, wherein the beam branching portion is incident on the elliptical reflecting mirror of the plurality of laser beams emitted from the beam branching portion. An exposure apparatus is characterized in that a region to be operated is configured to be asymmetric with respect to the optical axis of the elliptical reflecting mirror.
A seventh means is an exposure apparatus according to any one of the first means to the sixth means, wherein the optical member also serves as a plane reflecting mirror constituting the exposure optical system.
According to an eighth means, in any one of the first to seventh means, a laser beam attenuating member for attenuating the intensity of the laser beam reflected by the elliptical reflecting mirror after being incident on the discharge lamp. An exposure apparatus is provided outside the exposure optical system.

According to the first to fifth aspects of the present invention, the reflection light blocking area of light existing in the optical path of the elliptical reflecting mirror is avoided, and the reflection surface of the elliptical reflecting mirror is exposed from the opening side of the elliptical reflecting mirror. Since a plurality of laser beams are incident via the optical system, it is possible to efficiently guide the energy of the laser beams into the discharge vessel of the discharge lamp.
In addition, since the laser beam is spread over the entire elliptical reflector and condensed again on the light source, the energy density of the laser beam that passes through the discharge vessel of the light source can be lowered, holes are formed in the discharge vessel, and optical members are damaged. Will not cause problems such as giving.
According to the sixth aspect of the present invention, since the laser beam that has passed through the discharge vessel does not return to the laser oscillator, damage to the laser oscillator or unstable laser oscillation can be prevented.
According to the invention described in claim 7, it is not necessary to newly provide a beam splitter in the exposure optical system, and a laser beam can be easily introduced into the exposure optical system.
According to the eighth aspect of the present invention, an unnecessary laser beam can be attenuated by the laser beam attenuating member, and damage to the laser oscillator and its surroundings can be prevented.

A first embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a view showing the arrangement of an exposure apparatus according to the present embodiment.
In the figure, a discharge lamp 9 and an elliptical reflecting mirror 10 are housed in a lamp house 18, and the discharge lamp 9 has a pair of electrodes arranged in the discharge vessel in the direction of the optical axis of the elliptical reflecting mirror 10. This is a so-called electroded lamp provided with a pair of sealing parts that are connected to the container and extend in opposite directions and are arranged on the optical axis of the elliptical reflecting mirror 10. A typical example of the electroded lamp is a mercury vapor discharge lamp. The discharge lamp 9 is not limited to an electroded lamp, and may be an electrodeless lamp having no electrode in the discharge vessel.

  The laser oscillator 1 emits a laser beam 2, and the emitted laser beam 2 is expanded by a beam expander 3 for making a predetermined beam diameter, passes through a reflecting mirror 4, and becomes a laser beam 5. , Is incident on the beam branching unit 6. The laser beam 5 incident on the beam branching unit 6 is divided into a predetermined light intensity and becomes a plurality of laser beams 7 and 8. Note that the beam expander 3 is unnecessary if the laser beam 2 radiated from the laser oscillator 1 is focused on the collimator lens 13 and then fits on the reflecting surface of the elliptical reflecting mirror 10. Further, the laser oscillator 1, the beam expander 3, the reflecting mirror 4, and the beam branching unit 6 are disposed outside the optical system between one focal point of the elliptical reflecting mirror 10 and the integrator lens 11.

  The beam branching unit 6 includes a beam splitter 61 and a plane reflecting mirror 62, and emits a plurality of laser beams 7 and 8 when the laser beam 5 is incident thereon. The laser beam 5 incident on the beam splitter 61 is transmitted through and emitted as one laser beam 7, and the other laser beam 8 is reflected by the plane reflecting mirror 62 and emitted with the traveling direction changed. The plurality of laser beams 7 and 8 emitted from the beam branching unit 6 propagate in parallel to each other and are outside the reflected light inhibition region where the ultraviolet light 14 reflected from the elliptical reflecting mirror 10 of the reflecting mirror 12 which is an optical member is inhibited. Incident. The reflecting mirror 12 is disposed between at least the second focal point F2 of the elliptical reflecting mirror 10 and the integrator lens 11, and reflects the laser beams 7 and 8 and transmits the ultraviolet light 14 emitted from the discharge lamp 9. Has a selection function. The plurality of laser beams 7 and 8 reflected by the reflecting mirror 12 pass through the collimator lens 13, are collected near the aperture 15, and then spread, enter the elliptical reflecting mirror 10 while being reflected and spread by the planar reflecting mirror 16. And is incident on the discharge lamp 9 from a plurality of directions, and is collected in the first focal point F <b> 1 of the elliptical reflecting mirror 10 in the discharge lamp 9. In the present specification, the reflected light inhibition region of light existing in the optical path of the elliptical reflecting mirror 10 is reflected light that is mainly obstructed by the discharge lamp 9 on and around the front optical axis of the elliptical reflecting mirror 10. It is a region that becomes a dark part of light that is not condensed.

  When a plurality of laser beams 7 and 8 are incident on the discharge lamp 9, the discharge substance is excited, and the ultraviolet light 14 emitted from the discharge lamp 9 includes 365 nm i-line and 436 nm g-line. The mask surface 17 that is the object to be processed is irradiated through the exposure optical system. As the discharge lamp 9, usually a mercury lamp or a xenon mercury lamp is mainly used. As the laser oscillator 1, for example, a high-power laser of several tens of W or more such as a fiber laser having a wavelength of 1.06 μm is preferably used, and the driving method may be continuous wave (CW) oscillation or pulse oscillation. In the present invention, the type and emission wavelength of the discharge lamp used for exposure, the laser type and driving method of the laser oscillator are not particularly limited.

  In the present embodiment, the reflecting mirror 12 is disposed between the collimator lens 13 and the integrator lens 11, but the laser beams 7 and 8 incident on the collimator lens 13 and the ultraviolet light 14 emitted from the discharge lamp 9 are used. When chromatic aberration occurs, a lens having a long focal length may be disposed immediately before the incidence of the reflecting mirror 12. Since the light passing through the lens having a long focal length is slightly changed in direction from the traveling direction of the beam before entering the lens, it can be incident with the chromatic aberration of the collimator lens 13 corrected. Even if this long focal length lens is used, the incident laser beams 7 and 8 have almost no change in the incident angle for each part, and the thickness of the reflective multilayer film of the reflecting mirror 12 having a wavelength selection function is set for each part. There is no need to change it. Since this lens must be installed in a space between the collimator lens 13 and the integrator lens 11, it is necessary to improve the design of the exposure apparatus.

  When the reflecting mirror 12 is disposed between the aperture 15 (the second focal point F2 of the elliptical reflecting mirror 10) and the collimator lens 13, the laser beams 7 and 8 incident on the reflecting mirror 12 are shown in FIG. It is necessary to arrange a lens having a predetermined focal length at a predetermined position before entering the reflecting mirror 12 so as to have the same solid angle and focal point as the ultraviolet light 14 used for the exposure. Since there is originally a space that can be installed between the aperture 15 and the collimator lens 13, it is not necessary to improve the design of the exposure apparatus, but the incident angles of the incident laser beams 7 and 8 are different for each part. Therefore, it is necessary to change the thickness of the reflective multilayer film of the reflecting mirror 12 having the wavelength selection function for each part. For example, a reflective multilayer film that reflects 80% or more of the incident laser beams 7 and 8 needs to be deposited or deposited according to the incident angle of each part of the incident laser beams 7 and 8.

  After being used to excite the discharge substance in the discharge lamp 9, the laser beams 7 'and 8' that have not been absorbed pass through the discharge lamp 9 and follow the optical paths followed when the laser beams 8 and 7 are incident, respectively. Return to oscillator 1. At this time, the laser oscillator 1 is provided with an optical isolator (not shown) for preventing the returned laser beams 7 ′ and 8 ′ from returning to the main body of the laser oscillator 1.

A second embodiment of the present invention will be described with reference to FIGS.
FIG. 2 is a view showing the arrangement of the exposure apparatus according to the present embodiment.
The exposure apparatus of the present embodiment is different from the exposure apparatus of the first embodiment in that the configuration and arrangement of the beam branching unit 19 and the reflecting mirror 23 having a wavelength selection function are different. The other configurations correspond to the configurations with the same reference numerals shown in FIG.

  In FIG. 2, the beam branching unit 19 includes a beam splitter 191 that divides the laser beam 5 into a predetermined light intensity, and a parabolic reflector 192 that reflects and condenses one of the laser beams 20 reflected by the beam splitter 191. , A plane reflecting mirror 193 that changes the radiation direction of the other laser beam 21 that has passed through the beam splitter 191, and a parabolic reflector 194 that reflects and condenses the laser beam 21 emitted from the plane reflecting mirror 193, The laser beams 20 and 21 emitted from the paraboloid reflecting mirror 192 and the paraboloid reflecting mirror 194 are changed in the radiation direction by the reflecting mirror 22 and are incident on the reflecting mirror 23 which is an optical member. The reflecting mirror 23 has a wavelength selection function of reflecting the ultraviolet light 14 emitted from the discharge lamp 9 and transmitting the plurality of laser beams 20 and 21.

  The laser beam 2 radiated from the laser oscillator 1 passes through the beam expander 3 and then enters the beam branching unit 19 as a laser beam 5. The laser beam 20 branched and condensed from the beam branching unit 19. 21 is reflected by the plane reflecting mirror 22 along different optical paths, and is condensed at the same place as the second focal point F2 ′ of the elliptical reflecting mirror 10 and then passes through the reflecting mirror 23 while spreading. At this time, the laser beams 20 and 21 are transmitted outside the reflected light inhibition region. The reflecting mirror 23 is disposed at least between the first focal point F1 of the elliptical reflecting mirror 10 and the integrator lens 11, and the plurality of laser beams 20 and 21 transmitted through the reflecting mirror 23 enter the elliptical reflecting mirror 10 while spreading. By being reflected, the light is condensed from a plurality of directions and incident on the discharge lamp 9.

  Here, when a plane reflecting mirror is used instead of the parabolic reflecting mirrors 192 and 194, a lens is used to condense the laser beams 20 and 21 once immediately before the reflecting mirror 23 having a wavelength selection function. It may be installed. However, a lens having a predetermined focal length so as to have the same solid angle and focal point as the ultraviolet light 14 used for condensing in FIG. 1 should be installed at a predetermined position before entering the reflecting mirror 23 having a wavelength selection function. Need.

  FIG. 3 is a diagram showing a modification of the beam branching unit 19 shown in FIG. 2, and the beam branching unit 19 transmits the laser beam 5 into a predetermined light intensity and the beam splitter 195 transmitted through the beam splitter 195. A parabolic reflector 196 that reflects and condenses one laser beam 20 and a parabolic reflector 197 that reflects and condenses the other laser beam 21 reflected by the beam splitter 195 are configured. The radiation directions of the laser beams 20 and 21 emitted from the parabolic reflector 196 and the paraboloid reflector 197 are changed by the planar reflector 22, and then the plurality of laser beams 20 and 21 shown in FIG. As in the case of FIG.

  In the first and second embodiments, the laser beam has a light intensity that is low, or a light intensity that is within an allowable amount of an optical isolator (not shown) installed in the direction in which the laser beam is emitted from the laser oscillator 1. This is an example of using a beam. However, in the case where a laser beam having a light intensity higher than or equal to an allowable amount of an optical isolator (not shown) installed in a direction in which the laser beam is emitted from the laser oscillator 1 is used, The following third and fourth embodiments are employed.

A third embodiment of the present invention will be described with reference to FIGS.
FIG. 4 is a view showing the arrangement of the exposure apparatus according to the present embodiment.
The exposure apparatus of the present embodiment is different from the exposure apparatus of the first embodiment in that the configuration of the beam branching unit 24 is different. The other configurations correspond to the configurations with the same reference numerals shown in FIG.

  FIG. 5 is a diagram illustrating a configuration of the beam branching unit 24 illustrated in FIG. 4. The beam branching unit 24 includes a beam splitter 241, a plane reflecting mirror 242, and beam dampers 243 and 244. When 5 is incident, a plurality of laser beams 25 and 26 are emitted. The laser beam 5 incident on the beam splitter 241 passes through the beam splitter 241, is emitted as one laser beam 25, is reflected by the beam splitter 241, is further reflected by the plane reflecting mirror 242, and the traveling direction is changed. The other laser beam 26 is emitted. As shown in FIG. 4, the plurality of laser beams 25 and 26 emitted from the beam branching portion 24 become parallel light and are reflected by the reflecting mirror 12 which is an optical member. At this time, the laser beams 25 and 26 are reflected outside the reflected light inhibition region. On the other hand, laser beams 25 ′ and 26 ′ that have not been absorbed after being used to excite discharge substances in the discharge lamp 9 pass through the discharge lamp 9 and are different from the optical paths followed when the laser beams 25 and 26 are incident, respectively. It follows the optical path, enters the beam dampers 243 and 244 of the beam branching section 24, and does not return to the laser oscillator 1.

  In FIG. 6, laser beams 25 and 26 emitted from the beam branching portion 24 and passing through the virtual plane 27 are reflected by the elliptical reflecting mirror 10, and after the discharge substance is excited in the discharge lamp 9, the laser beam 25 not absorbed. FIG. 6 is a conceptual diagram schematically showing an optical path until it becomes “, 26” and is reflected again by the elliptical reflecting mirror 10 and returns to the beam dampers 243 and 244 of the beam branching section 24 through the virtual plane 27. According to the figure, it is understood that the laser beams 25 ′ and 26 ′ return to the beam dampers 243 and 244 without following the same optical path as the laser beams 25 and 26. As described above, when the laser beam has a high light intensity, or a laser beam having a light intensity higher than the allowable level of an optical isolator (not shown) installed in the direction in which the laser beam is emitted from the laser oscillator 1 is used. Can cause the beam dampers 244 and 245 to absorb the unabsorbed laser beams 25 ′ and 26 ′.

According to the exposure apparatus of this embodiment, as shown in FIG. 4, the laser beam 2 radiated from the laser oscillator 1 passes through the beam expander 3 and the reflecting mirror 4 having a predetermined beam diameter, and is then shown in FIG. As shown, the laser beam 25 transmitted by the beam splitter 241 and the laser beam 26 reflected by the beam splitter 241 and reflected again by the plane reflecting mirror 242 are again converted into parallel beams. Is incident on a transmission region through which the ultraviolet light 14 of the reflecting mirror 12 that is an optical member is transmitted. The reflecting mirror 12 is disposed between at least the first focal point of the elliptical reflecting mirror 10 and the integrator lens 11, and reflects the laser beams 25 and 26 and transmits the ultraviolet light 14 emitted from the discharge lamp 9. The plurality of laser beams 25 and 26 reflected by the reflecting mirror 12 pass through the collimator lens 13, are condensed near the aperture 15, spread afterwards, and reflected and spread by the planar reflecting mirror 16. By being incident on the ellipsoidal reflecting mirror 10 and reflected, the light is condensed from a plurality of directions and incident on the discharge lamp 9.
In FIG. 4, the laser beam 2 is expanded by the beam expander 3, and the beam diameter of the laser beam 5 is originally expanded. However, when the beam diameter is expanded as shown in FIGS. 1 and 2 shown in the first and second embodiments, the drawing display is complicated, so that the display is not expanded.

  As shown in FIG. 6, the beam transmitted through the discharge vessel is reflected at the position of the elliptical reflecting mirror 10 where the incident position is different from that of the laser beams 25 and 26 to become laser beams 25 ′ and 26 ′. The beams 25 ′ and 26 ′ pass through an optical path different from the optical path followed by the laser beams 25 and 26, are reflected by the plane reflecting mirror 16 while being collected, are collected near the aperture 15, and then spread, The light passes through the collimator lens 13, is reflected by the reflecting mirror 12, and is blocked by the beam dampers 243 and 244 installed at the positions shown in FIGS. 5 and 6.

  In addition, the reflecting mirror 12 is installed between the collimator lens 13 and the integrator lens 11, and between the wavelength of the laser beams 25 and 26 incident on the collimator lens 13 and the wavelength of the ultraviolet light 14 emitted from the discharge lamp 9. In the case where chromatic aberration occurs, a lens having a long focal length may be installed immediately before entering the reflecting mirror 12. The light that has passed through the lens having a long focal length can be changed in direction slightly from the traveling direction of the beam before entering the lens, so that it can be incident with the chromatic aberration of the collimator lens 13 corrected. By using this lens with a long focal length, the incident laser beams 25 and 26 have almost no change in the incident angle for each part, and the thickness of the reflective multilayer film of the reflecting mirror 12 having the wavelength selection function is made for each part. There is no need to change it. Since this lens must be installed in the space between the collimator lens 13 and the integrator lens 11, it is necessary to improve the design of the exposure apparatus.

  When the reflecting mirror 12 is disposed between the second focal point F2 (aperture 15) of the elliptical reflecting mirror 10 and the collimator lens 13, the laser beams 25 and 26 incident on the reflecting mirror 12 are shown in FIG. It is necessary to dispose a lens having a predetermined focal length at a predetermined position before entering the reflecting mirror 12 so as to have the same solid angle and focal point as the optical path 14 used for the exposure. Since there is originally a space between the aperture 15 and the collimator lens 13, there is no need to improve the design of the exposure apparatus, but the incident angles of the incident laser beams 25 and 26 are different for each part. It is necessary to change the thickness of the reflective multilayer film of the reflecting mirror 12 having a wavelength selection function for each part. For example, a reflective multilayer film that reflects 80% or more of the incident laser beams 25 and 26 needs to be deposited or deposited according to the incident angle of each part of the incident laser beams 25 and 26.

  Further, as shown in FIG. 7A, in order to reduce the diameters of the laser beams 25 and 26 emitted from the beam branching portion 24 and to reduce the transmission regions of the laser beams 25 and 26, the beam branching portion 24 is used. A reduction optical system 28 may be provided between the reflecting mirror 12 and the reflecting mirror 12. This is because there are a large number of optical elements arranged in the beam branching section 24, and depending on the size of the optical element used, the distance between the branched laser beams 25 and 26 is too far to fit in the reflecting mirror 12. Used for. As shown in FIG. 7B, the reduction optical system 28 is configured by combining convex lenses 281 and 282, and the focal lengths thereof are different. Basically, a convex lens 281 having a long focal length is arranged on the incident side of the laser beams 25 and 26, and a convex lens 282 having a short focal length is arranged on the emitting side of the laser beams 25 and 26. When the focal length f1 of the convex lens 281 having a long focal length and the focal length f2 of the convex lens 282 having a short focal length, the reduction ratio m is m = f2 / f1. FIG. 7C is a combination of a convex lens 283 and a concave lens 284, and each has a different focal length. The basic arrangement is that the convex lens 283 is arranged on the incident side of the laser beams 25 and 26 and the concave lens 284 is arranged on the emitting side of the laser beams 25 and 26. Assuming that the focal length f3 of the convex lens 283 and the focal length f4 of the concave lens 284 having a short focal length, the reduction ratio m is m = f4 / f3. The configuration shown in FIG. 7C is practical because the arrangement space is short compared to the configuration shown in FIG.

A fourth embodiment of the present invention will be described with reference to FIGS.
FIG. 8 is a view showing the arrangement of an exposure apparatus according to the present embodiment.
The exposure apparatus of the present embodiment is different from the exposure apparatus of the first embodiment in that the configuration of the beam branching unit 29 and the configuration and arrangement of the reflecting mirror 23 having a wavelength selection function are different. The other configurations correspond to the configurations with the same reference numerals shown in FIG.

  FIG. 9 is a diagram illustrating a configuration of the beam branching unit 29 illustrated in FIG. 8. The beam branching unit 29 includes a beam splitter 291, a parabolic reflecting mirror 292, a planar reflecting mirror 293, and a parabolic reflecting. When the laser beam 5 is incident on the beam branching portion 29, a plurality of laser beams 30 and 31 are emitted from the mirror 294 and beam dampers 295 and 296. The laser beam 5 incident on the beam splitter 291 is branched, transmitted through the beam splitter 291, reflected by the plane reflecting mirror 293, further reflected and collected by the parabolic reflecting mirror 294, and emitted as one laser beam 30. Then, it is reflected by the beam splitter 281, further reflected and collected by the parabolic reflector 292, and emitted as the other laser beam 31. As shown in FIG. 8, the reflected and focused laser beams 30 and 31 are changed in the radiation direction by the reflecting mirror 22 and are incident on the reflecting mirror 23 which is an optical member. The reflecting mirror 23 reflects the ultraviolet light 14 radiated from the discharge lamp 9, and the reflected light inhibition region where the plurality of laser beams 30, 31 are reflected from the elliptical reflecting mirror 10 of the reflecting mirror 23. It has a wavelength selection function to transmit outside. Although the laser beam 2 is expanded by the beam expander 3 and the beam diameter of the laser beam 5 is originally expanded, the beam diameter is expanded as shown in FIGS. 1 and 2 shown in the first and second embodiments. In this case, the drawing display is not expanded since it is complicated.

  FIG. 10 is a diagram illustrating a configuration of the beam branching unit 29 illustrated in FIG. 8, showing a configuration different from the beam branching unit 29 illustrated in FIG. 9. The beam branching unit 29 includes a beam splitter 291, a parabolic reflecting mirror 292, a parabolic reflecting mirror 294, and beam dampers 295 and 296, and the laser beam 5 is incident on the beam branching unit 29. Then, a plurality of laser beams 30 and 31 are emitted. The laser beam 5 incident on the beam splitter 291 is branched, transmitted through the beam splitter 291, reflected and collected by the parabolic reflector 294, emitted as one laser beam 30, reflected by the beam splitter 291, Further, the light is reflected and collected by a parabolic reflecting mirror 292 and emitted as the other laser beam 31.

  As shown in FIG. 8, the laser beam 2 emitted from the laser oscillator 1 is expanded by the beam expander 3 and is incident on the beam branching unit 29 as the laser beam 5. From the beam branching portion 29, the branched and condensed laser beams 30 and 31 are radiated toward the reflecting mirror 22. When the laser beams 30 and 31 are reflected by the planar reflecting mirror 22 along different optical paths, and after being condensed at the same place as the second focal point F2 ′ of the elliptical reflecting mirror 10, while spreading and passing through the reflecting mirror 23, The laser beams 30 and 31 are transmitted outside the reflected light inhibition region. The reflecting mirror 23 is disposed at least between the first focal point F1 of the elliptical reflecting mirror 10 and the integrator lens 11, and the plurality of laser beams 30 and 31 transmitted through the reflecting mirror 23 enter the elliptical reflecting mirror 10 while spreading. By being reflected, the light is condensed from a plurality of directions and incident on the discharge lamp 9.

  In FIG. 11, laser beams 30, 31 emitted from the beam branching portion 29 are incident on the elliptical reflecting mirror 10, reflected, and excited after the discharge substance in the discharge lamp 9, laser beams 30 ′, 31 not absorbed. It is the figure which looked at a mode that 'was reflected by the elliptical reflecting mirror 10 again from the optical axis direction of the elliptical reflecting mirror 10. FIG.

  After exciting the discharge substance in the discharge lamp 9, the laser beams 30 'and 31' that have not been absorbed pass through the discharge lamp 9 and are incident on the laser beam 30 and 31 as shown in FIG. Are reflected at different positions of the elliptical reflecting mirror 10. The laser beams 30 ′ and 31 ′ pass through an optical path different from the optical path followed by the laser beams 30 and 31, and pass through the planar reflecting mirror 23 while being condensed. Then, the light is condensed at the second focal point F <b> 2 ′, then spread and reflected by the planar reflecting mirror 22, and blocked by the beam dampers 295 and 296 installed at the positions shown in FIGS. 9 and 10.

  Here, in the case where a plane reflecting mirror is used instead of the parabolic reflecting mirrors 292 and 294 shown in FIGS. 9 and 10, the beam is once condensed immediately before entering the reflecting mirror 23 having a wavelength selection function. Therefore, a lens may be installed before the incidence. This lens has a lens with a predetermined focal length so as to have the same solid angle and focal point as the ultraviolet light 14 used for exposure in FIG. 8, and is placed at a predetermined position before entering the reflecting mirror 23 having a wavelength selection function. I need that.

  In the exposure apparatus according to the invention of each of the above embodiments, the number of branched laser beams is preferably two or more. When the laser beam is branched into a large number, the light intensity per unit area of the laser beam is reduced, whereby damage and significant deterioration of the optical component can be reduced, and laser beam incidence with a large solid angle can be realized. When the number of beams to be branched is two, if the energy density of one of the laser beams is increased, the optical element may be damaged. In order to reduce this possibility as much as possible, in each of the above embodiments, The used beam splitter preferably splits the light intensity of the beam into a transmitted beam having a light intensity of 50% with respect to the light intensity of the incident beam and a reflected beam having a light intensity of 50%. When the number of branched beams is n, if the energy density of any of the beams increases, the optical element may be damaged. In order to reduce this possibility as much as possible, the number of beam splitters and plane reflectors to be divided into predetermined light intensities is n−1, and the beam splitter to be divided into predetermined light intensities is the light intensity of the incident beam. On the other hand, it is preferable to divide into a transmitted beam having a light intensity of 100 / n% and a reflected beam having a light intensity of 100 (1-1 / n)%.

It is a figure which shows the structure of the exposure apparatus which concerns on invention of 1st Embodiment. It is a figure which shows the structure of the exposure apparatus which concerns on invention of 2nd Embodiment. It is a figure which shows the modification of the beam branching part 19 shown in FIG. It is a figure which shows the structure of the exposure apparatus which concerns on invention of 3rd Embodiment. It is a figure which shows the structure of the beam branching part 24 shown in FIG. It is the conceptual diagram which showed typically the optical path of the laser beams 25 and 26 and the laser beams 25 'and 26' which were not absorbed. 2 is a diagram showing a configuration of a reduction optical system 28 provided between a beam branching section 24 and a reflecting mirror 12. FIG. It is a figure which shows the structure of the exposure apparatus which concerns on invention of 4th Embodiment. It is a figure which shows the structure of the beam branching part 28 shown in FIG. FIG. 10 is a diagram showing a different configuration from the beam branching unit 28 shown in FIG. 9. It is the figure seen from the optical axis direction of the elliptical reflecting mirror. It is a figure which shows the semiconductor exposure apparatus of patent document 1 based on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser oscillator 2 Laser beam 3 Beam expander 4 Reflector 5 Laser beam 6 Beam branching part 61 Beam splitter 62 Planar reflecting mirrors 7 and 8 Laser beam 7 ', 8' Laser beam 9 which was not absorbed 9 Discharge lamp 10 Elliptical reflecting mirror 11 Integrator lens 12 Reflector 13 Collimator lens 14 Ultraviolet light 15 Aperture 16 Planar reflector 17 Mask surface 18 Lamp house 19 Beam branching section 191 Beam splitter 192 Parabolic reflector 193 Planar reflector 194 Parabolic reflector 195 Beam splitter 196 Parabolic reflecting mirror 197 Parabolic reflecting mirror 20, 21 Laser beam 22 Planar reflecting mirror 23 Reflecting mirror 24 Beam splitter 241 Beam splitter 242 Planar reflecting mirrors 243, 244 Beam dampers 25, 26 Laser beams 25 ', 26' Absorption The The laser beam 27 that has not been received Virtual surface 28 Reduction optical system 281, 282, 283 Convex lens 284 Concave lens 29 Beam splitter 291 Beam splitter 292 Parabolic reflector 293 Planar reflector 294 Parabolic reflector 295, 296 Beam damper 30, 31 Laser beam 30 ′, 31 ′ Laser beam not absorbed

Claims (8)

A discharge lamp, an elliptical reflecting mirror that reflects ultraviolet light radiated from the discharge lamp, an exposure optical system that irradiates an irradiated object with ultraviolet light reflected by the elliptical reflecting mirror, and supplies energy to the discharge lamp An exposure apparatus having a laser oscillator for incident a laser beam for performing
The laser oscillator and a beam branching section that divides a laser beam from the laser oscillator and emits a plurality of laser beams are disposed outside the exposure optical system,
An optical member having a wavelength selection function for introducing the laser beam is disposed on the optical path of the ultraviolet light reflected by the elliptical reflector,
The plurality of laser beams branched by the beam branching portion avoids the reflected light inhibition region of the ultraviolet light that is reflected by the elliptical reflector that exists in the optical path of the elliptical reflector via the optical member. An exposure apparatus that is incident on the elliptical reflecting mirror from the opening side of the elliptical reflecting mirror and is incident on the discharge lamp.   The discharge lamp includes a pair of electrodes disposed opposite to each other on the optical axis of the elliptical reflecting mirror in the discharge vessel, and extends in opposite directions to the discharge vessel and extends on the optical axis of the elliptical reflecting mirror. The exposure apparatus according to claim 1, further comprising a pair of sealing portions arranged.    The exposure apparatus according to claim 1, wherein the beam branching unit includes at least a beam splitter and a plane reflecting mirror.   The exposure apparatus according to claim 1, wherein the beam branching unit includes at least a beam splitter and a plurality of parabolic reflecting mirrors.   5. The exposure optical system includes a collimator lens and an integrator lens, and the optical member is disposed between the collimator lens and the integrator lens. An exposure apparatus according to one claim.   The beam branching unit is configured such that regions of the plurality of laser beams emitted from the beam branching unit are incident on the elliptical reflecting mirror are asymmetric with respect to the optical axis of the elliptical reflecting mirror. 6. The exposure apparatus according to any one of claims 1 to 5, wherein the exposure apparatus is provided.   The exposure apparatus according to claim 1, wherein the optical member also serves as a plane reflecting mirror that constitutes the exposure optical system.   8. A laser beam attenuating member for attenuating the intensity of a laser beam reflected by the elliptic reflecting mirror after entering the discharge lamp is provided outside the exposure optical system. An exposure apparatus according to one claim.