JP5708925B2 - Exposure apparatus and exposure optical apparatus - Google Patents

Description

  The present invention relates to an exposure apparatus and an optical apparatus for exposure that guide coherent light such as laser light to the surface of a photosensitive medium.

  In photolithography used for forming an exposure apparatus, for example, a circuit pattern of a semiconductor element or the like, a technique of transferring a reticle (mask) pattern onto a substrate such as a semiconductor wafer is employed. In this method, a photosensitive photoresist is applied on a substrate, a reticle is placed on the photoresist, and a high pressure mercury lamp, a metal halide lamp, etc. are placed above the reticle to irradiate the reticle. . Thereby, an irradiation light image corresponding to the reticle pattern is formed on the photoresist.

  In general, in a projection exposure apparatus, a pattern to be transferred drawn on a reticle is projected onto a substrate as an object to be exposed via a projection optical system to form an image. However, high-intensity discharge lamps such as high-pressure mercury lamps have a relatively short life and require frequent lamp replacement. Furthermore, the specification of a high-pressure mercury lamp that uses mercury is not preferable from the viewpoint of environmental load. In addition, since it is a divergent light source including a plurality of wavelengths, it is necessary to prepare a relatively large and highly functional optical system for condensing, shaping, and imaging, and there is a problem that the entire apparatus becomes large. .

  In order to cope with such a problem, a method using a coherent light source such as a laser has been proposed. For example, a semiconductor laser widely used in the industry has a very long life compared to a high-intensity discharge lamp such as a high-pressure mercury lamp. In addition, since it is a light source that can generate light with a single wavelength and high linearity, the optical system can be made small and simple, and the entire apparatus can be miniaturized to improve the light utilization efficiency. Has the advantage of being

  On the other hand, the generation of speckle becomes a problem in the method using a coherent light source such as a laser beam. Speckle is speckled noise that appears when a scattering surface is irradiated with coherent light such as laser light. When it occurs in a projector or the like that projects an image, luminance unevenness ( (Unevenness in brightness) is observed, which deteriorates the projected image and causes physiological adverse effects on the observer. The reason that speckle occurs when coherent light is used is that coherent light reflected by a scattering reflection surface such as a screen interferes with each other due to its extremely high coherence.

  When such coherent light is used in an exposure apparatus, speckles generated due to the coherent light cause partial irradiation unevenness on the substrate, resulting in loss of the photoresist image, thereby forming This causes problems such as the loss of the circuit to be generated.

  In order to reduce this speckle noise, various attempts have been made, such as vibrating the diffusion plate through which the laser beam passes, expanding the wavelength spectrum of the laser spectrum, and vibrating the screen itself that is the target of the laser beam irradiation. . As an attempt to reduce such speckle noise, Patent Document 1 discloses a non-speckle display device that reduces speckle noise by rotating a diffusion element through which coherent light passes.

Japanese Patent Laid-Open No. 6-208089

  However, in the speckle reduction method described in Patent Document 1, speckle noise (interference pattern) generated before reaching the diffusing element can be averaged, but the incident ray angle from the diffusion center to the screen is any Since the light scattering characteristics at each point on the screen are also constant, there is a problem that the effect of removing speckle noise generated on the screen is hardly obtained.

  Although the speckle reduction method described in Patent Document 1 can be applied to an exposure apparatus that uses coherent light, as with this screen, specs generated on a substrate as an object to be exposed. Cannot be removed effectively.

  An object of the present invention is to provide an exposure apparatus that suppresses speckles generated when coherent light is used as a light source and illuminates a substrate as an object to be exposed uniformly.

In order to solve the above-described problems, an exposure apparatus according to the present invention includes:
A diffuser that diffuses incident light;
An illumination system that illuminates the diffuser plate over time with coherent light and illuminates by changing the incident angle to each point of the diffuser over time, and
An optical modulator having a patterned region;
A condensing optical system for condensing the coherent light emitted from the diffusion plate on the pattern formation region;
And an imaging optical system for imaging the surface of the object to be exposed with the modulated coherent light in the optical modulator,
The illumination system is
A light source that emits coherent light;
An optical scanning unit that scans coherent light emitted from the light source;
The scanning light scanned by the optical scanning unit is diffused, and the diffused light emitted from each point is illuminated with coherent light by overlapping the diffuser plate over time, and the incident angle to each point of the diffuser plate is changed. A light diffusing element that changes illumination over time and illuminates,
The light diffusing element is a lens array.

In order to solve the above-described problem, an exposure apparatus according to the present invention includes:
A diffuser that diffuses incident light;
An illumination system that illuminates the diffuser plate over time with coherent light and illuminates by changing the incident angle to each point of the diffuser over time, and
An optical modulator having a patterned region;
A condensing optical system for condensing the coherent light emitted from the diffusion plate on the pattern formation region;
And an imaging optical system for imaging the surface of the object to be exposed with the modulated coherent light in the optical modulator,
The illumination system is
A light source that emits coherent light;
An optical scanning unit that scans coherent light emitted from the light source;
A lens array having a plurality of element lenses and diverging the light scanned by the light scanning unit;
An optical path conversion system configured to suppress the divergent angle of divergent light emitted from each point of the lens array and to irradiate the diverged light with the divergent angle suppressed over the illuminated region over time, and It is characterized by providing.

Furthermore, in the exposure apparatus according to the present invention,
The light modulator is a transmissive or reflective photomask.

Furthermore, in the exposure apparatus according to the present invention,
The optical modulator is a transmissive or reflective display element that forms an image based on an input video signal.

Furthermore, in the exposure apparatus according to the present invention,
A first diaphragm disposed in the vicinity of the diffusion plate and a second diaphragm disposed in the imaging optical system;
The first diaphragm and the second diaphragm are conjugate.

  According to the exposure apparatus of the present invention, the diffusion plate that illuminates the light modulator is illuminated with the coherent light superimposed over time, and the incident angle to each point of the diffusion plate is changed over time to illuminate. Thus, it is possible to perform exposure while effectively suppressing speckles generated on the object to be exposed and suppressing illumination unevenness.

The figure which shows the structure of the exposure apparatus which concerns on embodiment of this invention The figure which shows the structure of the illumination system which concerns on embodiment of this invention. The figure which shows the mode of the hologram production used with the illumination system which concerns on embodiment of this invention The figure which shows the mode of the optical scanning which concerns on embodiment of this invention. The figure which shows the mode of the optical scanning which concerns on other embodiment of this invention. The figure which shows the structure of the illumination system which concerns on other embodiment of this invention. The figure which shows the mode of hologram creation used with the illumination system which concerns on other embodiment The figure which shows the structure of the other illumination system which concerns on embodiment of this invention.

  Now, an exposure apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a view showing the arrangement of an exposure apparatus according to an embodiment of the present invention. Note that the drawings described below are schematic views and may differ from actual shapes, dimensions, and arrangements.

  The exposure apparatus 10 of the present embodiment includes an illumination system 20, a diffusion plate 31, a first diaphragm 32, a condensing optical system 33, a light modulator 34, and an imaging optical system 35, and An image formed on the light modulator 34 is exposed on the exposure target 36. In the figure, the surface of the object to be exposed 36 is the XY plane, and the axis perpendicular to the XY plane is the Z axis.

The illumination system 20 is an optical system that illuminates the diffusing plate 31 as an illuminated region, and changes the incident angle of the diffusing plate 31 with respect to the effective region with the illuminating light Lb that changes its direction with time and exits. The diffusing plate 31 is illuminated while being illuminated. At that time, the illumination light Lb changes direction over time,
It is necessary that the illumination light Lb emitted at each time is overlapped with time to illuminate the entire effective area of the diffusion plate 31. Preferably, the illumination light Lb depends on the emission direction of the illumination light Lb. Instead, the effective area of the diffusing plate 31, that is, the entire area in the diffusing plate 31 necessary for forming an image on the object to be exposed 36 is always illuminated. In this way, it is possible to make the luminance of the formed image uniform. Various configurations can be adopted for the detailed configuration of the illumination system 20 and will be described in detail later.

  The diffusing plate 31 is an optical element that diffuses incident light, and for example, glass having one surface processed into a ground glass (opaque), opal glass, or a random phase diffusing plate is used. In addition, a hologram, a microlens array, or the like may be used as the diffusion plate 31. In this embodiment, by providing such a diffuser plate 31, coherent light diffused by the diffuser plate 31 is incident on the optical modulator 34, and is generated by the optical modulator 34 and other optical components. It is possible to make the speckle to be inconspicuous.

  The condensing optical system 33 is an optical element that condenses the coherent light emitted from the diffusion plate 31 on the pattern formation region of the optical modulator 34. In the present embodiment, the light utilization efficiency is improved by condensing the coherent light emitted from the diffusion plate 31 in the pattern formation region. The condensing optical system 33 is a conjugate of the first diaphragm 32 disposed in the vicinity of the diffusion plate 31 and the second diaphragm 35b disposed in the imaging optical system 35, so that light modulation is performed. The imaging characteristics at all positions of the vessel are made uniform. The first diaphragm 32 may be formed by the diffusion plate 31 or the edge of its effective area.

  The light modulator 34 is, for example, a transmissive or reflective reticle (photomask). In this case, an optical image corresponding to the reticle pattern is formed on the surface of the object to be exposed 36 and can be used as an exposure apparatus for manufacturing a semiconductor element. The light modulator 34 may be a display element such as a liquid crystal micro display that forms an image based on an input video signal instead of the photomask. Also in this case, the display element may be either a transmission type or a reflection type. The light modulator 34 illuminated by the diffusing plate 31 selects coherent light for each pixel and transmits or reflects it, whereby a modulated image (light image) having a fine pattern can be formed on the exposed object 36.

  The object to be exposed 36 is a semiconductor wafer for forming a resist pattern, for example. In particular, the type of the object to be exposed 36 is not limited and may be a film coated with a photosensitive agent.

  The image forming optical system 35 is an optical element that forms an image formed on the light modulator 34 on the object to be exposed 36 and exposes it. In this embodiment, the image forming optical system 35 is disposed between the pair of convex lenses 35a and 35b. The second diaphragm 35b is configured. As described above, the second diaphragm 35b is conjugate with the first diaphragm 32 disposed in the vicinity of the diffusion plate 31.

  The configuration of the exposure apparatus according to the embodiment of the present invention has been described above. In the present embodiment, by adopting such a configuration, the object 36 is exposed to the image formed on the optical modulator 34. The accuracy is improved by suppressing the speckle of the image.

  Now, the principle of speckle suppression in the exposure apparatus 10 will be described. As shown in FIG. 1, the illumination light Lb (t1) emitted from the illumination system 20 illuminates at least a part of the diffusion plate 31 region. Similarly, the illumination light Lb (t2) at time t2 illuminates at least a part of the diffusion plate 31. As shown in this figure, the illumination system 20 illuminates the entire effective area of the diffusion plate 31 while changing the incident angle with time. The effective area of the diffusing plate 31 is preferably set to an area that is always illuminated regardless of the direction of the illumination light Lb emitted from the illumination system 20 in order to achieve uniform luminance.

  The light emitted from the diffusion plate 31 illuminates the light modulator 34 via the condensing optical system 33. At this time, the condensing optical system 33 illuminates the entire pattern formation region of the light modulator 34. Further, since the illumination light Lb incident on the diffusion plate 31 is incident with the incident angle changed over time, the diffused light emitted from the diffusion plate 31 also illuminates the light modulator 34 while changing the angle over time. Will be. Accordingly, speckles generated in the pattern formation region of the light modulator 34 are overlapped and averaged over an exposure time period that is an illumination time for the exposure object 36, and as a result, are generated on the exposure object 36. Irradiation unevenness can be suppressed, and the image formed on the light modulator 34 can be accurately exposed on the exposure target 36.

  In the present embodiment, the illumination system 20 that illuminates the diffusion plate 31 while changing the incident angle with time will be described. In the present embodiment, diffused light emitted from the light diffusing element is used as the illumination light Lb that illuminates the diffuser plate 31.

  FIG. 2 is a diagram showing a configuration of the illumination system 20 according to the embodiment of the present invention. The illumination system 20 of the present embodiment includes a light source 11, a light scanning unit 15, and a light diffusing element 21 (hologram). In the illumination system 20, the exposure optical device referred to in the present invention is configured with other configurations excluding the light source 11.

  As the light source 11, various laser devices such as a semiconductor laser device that emits laser light as coherent light are used. The coherent light emitted from the light source 11 illuminates the optical scanning unit 15.

  The optical scanning unit 15 is a mirror device that can rotate the reflection surface around the rotation center Ra, and mechanically rotates a movable mirror such as a polygon mirror, a galvano scanner, or a MEMS scanner. Is used. In addition, various forms such as an acousto-optic effect scanner that modulates the refractive index can be employed. In one exposure time in the exposure apparatus 10, it is preferable that the optical scanning unit 15 optically scans the light diffusing element 21 for at least one period.

  The coherent light emitted from the light source 11 is incident on the reflection surface of the optical scanning unit 15. At this time, the coherent light is reflected on the reflection surface with little positional variation when the optical scanning unit 15 rotates. It is preferably incident on the upper point (hereinafter also referred to as “reference point”). By making the coherent light incident on such a reference point, when the hologram is used for the light diffusing element 21, the condensing position of the reference light used when creating the hologram is set as the reference point of the optical scanning unit 15. It is possible to obtain a recorded hologram reproduction image with certainty.

  Here, the light diffusing element 21 scanned with the scanning light La by the light diffusing unit 15 will be described. The light diffusing element 21 is an optical element that illuminates the illuminated area, that is, the entire effective area of the diffusing plate 31 when the scanning light La is incident thereon. In this embodiment, a transmission hologram is used. By employing a hologram as the light diffusing element 21, it becomes possible to always obtain the same reproduced image regardless of the incident position of the scanning light La, and the entire effective area of the diffusing plate 31 serving as an illuminated area can be evenly distributed. Can be illuminated. Further, the beam cross-sectional shape of the scanning light La incident on the hologram or the incident angle thereof can be given freedom, and the layout of the apparatus can be made flexible.

The light diffusing element 21 is not limited to such a hologram, but may be any optical element that allows the diffused light emitted from each point to illuminate the diffusion plate 31, and diffused light emitted from each point is diffused. It is preferable to illuminate the entire plate 31. For example, a lens array in which fine lenses are arranged in an array, or a so-called normal diffusion plate such as opal glass, ground glass, or a resin diffusion plate may be used. Note that “diffusion” in the light diffusing element in the present invention means that incident light is angularly expanded in a predetermined direction and emitted, and the diffusion angle is sufficiently controlled like a diffractive optical element or a lens array. Not only the case but also the case where the emission angle is expanded by scattering particles such as opal glass is included.

  The transmission hologram as the light diffusing element 21 used in the present embodiment reproduces the diffusion plate image 22i as a recorded reproduction image. The coherent light emitted from the light source 11 is reflected by the rotating light scanning unit 15 to be scanned light La and scans back and forth on the incident surface of the light diffusing element 21. The figure shows the state of the scanning lights La (t1) and La (t2) at certain times t1 and t2. The light diffusing element 21 of the present embodiment uses a transmission hologram that forms a reproduced image with respect to light (reproduced illumination light) having a predetermined incident angle. The scanning light La scanned by the optical scanning unit 15 is set to be reproduction illumination light for the transmission hologram at any scanning position. The creation of a transmission hologram used in this embodiment will be described later.

  As shown in FIG. 2, the scanning light La (t1) at time t1 emits illumination light Lb (t1) as reproduction light at the light diffusing element 21 to form a diffusion plate image 22i. Further, the scanning light La (t2) at time t2 emits the illumination light Lb (t2) by the light diffusing element 21 to form the same diffusing plate image 22i. By scanning the scanning light La in this way, the diffusion plate images 22i are formed so as to overlap each other when the incident position of the light diffusing element 21 is irradiated. By positioning the diffusing plate image 22i so as to include the entire effective area of the diffusing plate 31, it becomes possible to uniformly illuminate the entire effective area at any scanning position.

  FIG. 3 is a diagram showing a configuration (interference exposure) when recording (creating) a transmission hologram used in the illumination system 20 according to the embodiment of the present invention. Laser light is irradiated from the back side of the diffusion plate 22, and the object light Ob diffused forward is incident from one surface of the hologram recording material 24. At that time, diffused light (object light Ob) from each point of the diffusion plate 22 is diffused so as to illuminate at least the entire use region of the hologram recording material 24.

  Then, the reference light R condensed by the condensing optical system 23 is irradiated from the same surface of the hologram recording material 24. The focal position A of the condensing optical system 23 is arranged so as to coincide with a reference point by the optical scanning unit 15 in use. The object light Ob and the reference light R are simultaneously incident and interfered in the hologram recording material 24. The object beam Ob and the reference beam need to have coherency. Therefore, it is conceivable to divide laser light oscillated from the same light source and use one as object light Ob and the other as reference light R.

  The hologram recording material 24 is subjected to a predetermined development process, and a transmission hologram 21 for reproducing a diffuser plate image at the same position is created at each point on the surface. Further, for irradiation of the object light Ob used at the time of recording, not only the diffuser plate 22 such as an opal glass file, but also an optical element (light diffusing element 21) such as a lens array, which can illuminate the entire use area with diffused light from each point. (Referred to as “second light diffusing element”). In the present embodiment, interference fringes are recorded (interference exposure) by causing the object beam Ob and the reference light R to interfere with each other. However, the interference fringes calculated by the computer are directly recorded on the hologram recording material 21. A so-called computer-generated hologram may be used.

A diffusion plate image 22i reproduced by the light diffusion element 21 in FIG. 2 is positioned so as to illuminate the entire effective area of the diffusion plate 31 in FIG. FIG. 4 shows an embodiment of the optical scanning unit 15 that performs one-dimensional scanning. In this embodiment, the coherent light emitted from the light source unit 11 is reflected on the reflection surface of the optical scanning unit 15 that resonates and vibrates in one axial direction, and scans the light diffusion element 21 back and forth on the line. When a hologram is used as the light diffusing element 21, a diffusing plate image 22i is formed at any scanning position. In such an embodiment, the light diffusion element 21 can be reduced in size because the scanning region only needs to be a line. In order to obtain a sufficiently illuminated area by line-shaped scanning, it is preferable to use a hologram.

  FIG. 5 shows an embodiment of the optical scanning unit 15 that performs two-dimensional scanning. In this embodiment, the coherent light from the light source unit 11 is reflected on the reflection surface of the optical scanning unit 15 that resonates and oscillates in two axial directions, and scans the light diffusion element 21 two-dimensionally. Also in this embodiment, the diffused light from the light diffusing element 21 sufficiently illuminates the entire illuminated area, and in particular when a hologram is used, a diffuser plate image shaped to match the illuminated area. 22i can be formed, and the light use efficiency is increased. Such an embodiment is effective when a normal diffusion plate such as opal glass is used. Even if the illuminance distribution of diffused light from each point is not constant, the illuminance can be averaged and the entire illuminated area can be illuminated uniformly.

  In the embodiment of FIG. 2, the transmissive light diffusing element 21 is used. However, as the light diffusing element 21, a reflective type may be used. 6 and 7 show an embodiment when a reflection hologram is used as the light diffusing element 21, and each drawing corresponds to the transmission type shown in FIGS. 2 and 3, respectively.

  FIG. 6 is a diagram showing a configuration of the illumination system 20, and is an embodiment using a reflection hologram as the light diffusing element 21. Similar to the above-described embodiment, the scanning light La from the optical scanning unit 15 performs scanning while changing the position of the incident surface of the light diffusing element 21 in terms of time. In the reflection hologram, this incident surface also functions as a reflection surface, and the reflected reproduced image illuminates the entire effective area of the diffusion plate 31 as in the previous embodiment. Regardless of which point of the light diffusing element 21 is scanned, the diffused light emitted from each point can illuminate the effective area of the diffuser plate 31 to vary the incident angle with respect to the effective area in terms of time. It becomes possible. Therefore, as in the previous embodiment, speckles generated on the screen 41 and speckles generated in various optical elements of the exposure apparatus 10 can be made sufficiently inconspicuous.

  FIG. 7 is a diagram showing a configuration (interference exposure) when creating a reflection hologram used in the present embodiment. Laser light is irradiated from the back side of the diffusion plate 22, and the object light Ob diffused forward is incident from one surface of the hologram recording material 24. At that time, diffused light (object light Ob) from each point from the diffusion plate 22 is diffused so as to illuminate at least the entire use region of the hologram recording material 24.

  Then, the reference light R condensed by the condensing optical system 23 is irradiated from the other surface of the hologram recording material 24. The focal position A of the condensing optical system 23 is arranged so as to coincide with a reference point by the optical scanning unit 15 in use. The object light Ob and the reference light R are simultaneously incident and interfered in the hologram recording material 24.

  The hologram recording material 24 is subjected to a predetermined development process, and a reflection hologram 21 for reproducing a diffuser plate image at the same position is created at each point on the surface. As in the previous embodiment, the object light Ob is irradiated not only with the diffuser plate 22 such as an opal glass file, but also with an optical element (second lens) such as a lens array that can illuminate the entire use area. Light diffusing element). Moreover, it is good also as using a computer-generated hologram also about this reflection type hologram.

The optical system 20 described above uses diffused light emitted from each point of the light diffusing element 21 such as a hologram as the emitted illumination light Lb. In addition to using the diffused light emitted from the light diffusing element 21 as described above, the following embodiment can also be adopted for the optical system 20.

  FIG. 8 is a diagram showing a configuration of an illumination system 20 according to another embodiment of the present invention. The illumination system 20 of this embodiment includes a light source 11, an optical scanning unit 15, a first optical path conversion system 25, a lens array 26, and a second optical path conversion system 27. In this embodiment as well, the exposure optical apparatus referred to in the present invention is configured with another configuration excluding the light source 11 in the illumination system 20. At this time, the first optical path conversion system 25 is not an essential configuration.

  Details of the configuration of the light source 11, the optical scanning unit 15, and the like are the same as those in the above-described embodiment, and thus the description thereof is omitted here. In addition, it is preferable to provide beam shaping means for uniforming the intensity distribution in the cross-sectional direction of the coherent light emitted from the light source 11. As a design example, a beam shaping unit is provided so as to be uniform on a surface in the vicinity of the optical scanning unit 15, and the surface to be illuminated and the surface of the one-dimensional light modulation element are set to be conjugate so that the illuminated area has a uniform intensity. It becomes possible to illuminate with.

  The optical scanning unit 15 of the present embodiment has a rotation center Ra in the Y-axis direction, and performs one-dimensional scanning that scans coherent light in the XZ plane. Even in this case, it is necessary to scan the incident surface of the lens array 26 and to illuminate the illuminated area sufficiently as a result.

  The coherent light incident from the light source 11 becomes scanning light La whose direction changes temporally in the optical scanning unit 15, and enters the lens array 26 through the first optical path conversion system 25. In the figure, the states of the scanning light La (t1) and La (t2) near the outermost end are shown, but actually the scanning light La passes between La (t1) and La (t2). It will move continuously.

  The first optical path conversion system 25 is an optical element that converts the scanning light La from the scanning unit 15 so as to be incident substantially perpendicular to the incident surface of the lens array 26, and uses a convex lens having a condensing function. Configured. By making the scanning light La ′ thus converted perpendicularly incident on each element lens constituting the lens array 26, the scanning light La ′ is incident on each element lens under the same conditions. . Therefore, it is possible to reduce the design burden, for example, by making the design of each element lens of the lens array 26 equal. The first optical path conversion system 25 is not necessarily provided, and can be dealt with by changing the element lenses constituting the lens array 26 and subsequent optical systems in accordance with the state of incident light. It is.

  The lens array 26 is an optical element in which a plurality of element lenses are arranged at a light scanning position (on the XY plane) by the light scanning unit 15, and the scanning light La ′ incident on each element lens is diverged. Convert to Lb ′. The size and shape of the element lens constituting the lens array 26 can be appropriately set as necessary. For example, a cylindrical lens array using a cylindrical lens as the shape of the element lens can be used. A microlens array composed of extremely small element lenses may be used.

  Furthermore, in this embodiment, each element lens has a configuration in which a plurality of stages (two stages) are arranged in the optical axis direction (Z-axis direction). The coherent light emitted from the light source 11 is not necessarily emitted as parallel light, and may include a scattered component that is somewhat deviated from the parallel state. In the present embodiment, this scattering component can be suppressed by arranging a plurality of element lenses in the optical axis direction. The element lenses arranged in the optical axis direction have the same diameter and are arranged such that the central axis is aligned with the light traveling direction. The lens array 26 may have a configuration in which each element lens is configured in one stage in the optical axis direction.

The second optical path conversion system 27 (“optical path conversion system” in the present invention) is an optical element that illuminates the diffusing plate 31 as an illuminated area with the illumination light Lb emitted from the lens array 26. The illumination light Lb emitted from each point of the lens array 26 optically scanned by the optical scanning unit 15 illuminates the illuminated area with the illumination light Lb so as to overlap with time through the second optical path conversion system 27. . The second optical path conversion system 27 preferably has a condensing function for diverging light Lb ′ emitted from the lens array 26 to illuminate an effective area of the diffusion plate 31 as an illuminated area. By suppressing the divergence angle of the diverging light Lb ′ diverged by the lens array 26 and condensing it on the effective area of the diffusing plate 31, the light utilization efficiency can be improved. Furthermore, it is preferable that the second optical path conversion system 27 converts the divergent light Lb ′ so as to become parallel light or substantially parallel light. By illuminating the effective area of the diffusing plate 31 as parallel light or substantially parallel light, it is possible to illuminate each position of the effective area under substantially the same condition. For example, the entire effective area can be illuminated uniformly. It becomes.

  Note that the second optical path conversion system 27 only needs to have a function of suppressing the divergence angle, and a combination of a lens, a concave mirror, a mirror, and a prism is used. You may implement | achieve with the hologram element, diffraction element, etc. which have an equivalent function. Moreover, you may implement | achieve by these combination.

  The illumination light Lb emitted from the second optical path conversion system 27 illuminates at least a part of the effective area of the diffusion plate 31 at each time point, and illuminates the entire effective area by scanning the optical scanning unit 15. Although it is sufficient, it is preferable that the illumination light Lb illuminates the entire effective area at each time point. According to such a configuration, the luminance distribution in the effective area of the diffusion plate 31 can be made uniform.

  Even in the case of using the illumination system 20 as in the present embodiment, the effective areas of the diffuser plate 31 are overlapped with time and illuminated with coherent light, and the incident angle to each point of the effective area is changed with time. Can be illuminated. As a result, the diffused light emitted from the diffusing plate 31 is averaged on the light modulator 34 to suppress the generation of speckles, and as a result, the uneven irradiation of the image formed on the exposed object 36 is eliminated. Thus, the image formed on the light modulator 34 can be exposed to the exposed object 36 with high accuracy.

  Note that the present invention is not limited to these embodiments, and embodiments configured by appropriately combining the configurations of the respective embodiments also fall within the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Exposure apparatus 11 ... Light source 15 ... Optical scanning part 20 ... Illumination system 21 ... Light diffusing element 22 ... Diffuser 25 ... 1st optical path conversion system 26 ... Lens array 27 ... 2nd optical path conversion system 31 ... Diffuser 32 ... 1st 1 stop 33 ... condensing optical system 34 ... light modulator 35 ... imaging optical systems 35a and 35c ... convex lens 35b ... second stop 36 ... object to be exposed

Claims (5)

A diffuser that diffuses incident light;
An illumination system that illuminates the diffuser plate over time with coherent light and illuminates by changing the incident angle to each point of the diffuser over time, and
An optical modulator having a patterned region;
A condensing optical system for condensing the coherent light emitted from the diffusion plate on the pattern formation region;
And an imaging optical system for imaging the surface of the object to be exposed with the modulated coherent light in the optical modulator,
The illumination system is
A light source that emits coherent light;
An optical scanning unit that scans coherent light emitted from the light source;
The scanning light scanned by the optical scanning unit is diffused, and the diffused light emitted from each point is illuminated with coherent light by overlapping the diffuser plate over time, and the incident angle to each point of the diffuser plate is changed. A light diffusing element that changes illumination over time and illuminates,
The exposure apparatus , wherein the light diffusing element is a lens array . A diffuser that diffuses incident light;
An illumination system that illuminates the diffuser plate over time with coherent light and illuminates by changing the incident angle to each point of the diffuser over time, and
An optical modulator having a patterned region;
A condensing optical system for condensing the coherent light emitted from the diffusion plate on the pattern formation region;
And an imaging optical system for imaging the surface of the object to be exposed with the modulated coherent light in the optical modulator,
The illumination system is
A light source that emits coherent light;
An optical scanning unit that scans coherent light emitted from the light source;
A lens array having a plurality of element lenses and diverging the light scanned by the light scanning unit;
An optical path conversion system configured to suppress the divergent angle of divergent light emitted from each point of the lens array and to irradiate the diverged light with the divergent angle suppressed over the illuminated region over time, and An exposure apparatus comprising: an exposure apparatus; 3. The exposure apparatus according to claim 1, wherein the light modulator is a transmissive or reflective photomask. 4. The exposure apparatus according to claim 1 , wherein the optical modulator is a transmissive or reflective display element that forms an image based on an input video signal. . A first diaphragm disposed in the vicinity of the diffusion plate and a second diaphragm disposed in the imaging optical system;
5. The exposure apparatus according to claim 1, wherein the first diaphragm and the second diaphragm are conjugate.

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