JP4502596B2 - Pattern drawing method and pattern drawing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pattern drawing method and a pattern drawing apparatus applied to a mask drawing apparatus used for manufacturing a mask used in an exposure process at the time of manufacturing a semiconductor integrated circuit. The present invention also provides a pattern drawing method and a pattern drawing apparatus that can be applied to a maskless exposure apparatus that directly draws a circuit pattern on a wafer without using a mask.
[0002]
[Prior art]
In general, in an exposure process at the time of manufacturing a semiconductor integrated circuit, a circuit pattern is drawn on a resist-coated wafer using a mask (also referred to as a reticle) on which a circuit pattern is drawn (called pattern exposure). .) There is a need, and an apparatus for this purpose is called an exposure apparatus or an exposure machine.
[0003]
On the other hand, in order to manufacture a mask, it is necessary to provide a light-shielding chromium film or the like on the surface of a quartz plate or the like serving as a mask substrate so that exposure light passes in a pattern corresponding to a target circuit pattern. . The chromium film or the like is formed by pattern exposure, and an apparatus that performs the pattern exposure is called a mask drawing apparatus. As a mask drawing apparatus technique, electron beam drawing using an electron beam is generally used, and an apparatus for that purpose is called an electron beam drawing apparatus (hereinafter referred to as an EB drawing apparatus).
[0004]
However, in addition to the EB drawing device, the mask drawing device uses a laser beam in the ultraviolet region (hereinafter abbreviated as an ultraviolet laser beam) to draw a pattern (that is, pattern exposure to a mask substrate coated with a resist). An apparatus based on this technique (sometimes called a laser beam drawing apparatus) has also been commercialized. As a conventional example of the apparatus, a device in which a large number of micromirrors are arranged in a two-dimensional array (referred to as a digital micromirror device or the like, but hereinafter abbreviated as a mirror device) is used. The pattern is drawn on the mask substrate by controlling the reflected light in a pattern. This laser beam drawing apparatus is known to have a high processing speed because a part of the circuit pattern can be exposed at a time. This is shown in, for example, Non-Patent Document 1 or Patent Document 1.
[0005]
According to this, in a conventional laser beam drawing apparatus using a mirror device, a mirror device using about 1 million (about 500 × about 2000) micromirrors is used, and each micromirror has a size of about 16 microns. That's it. This is reduced and projected to a size of 1/160 on the mask substrate by a reduction projection optical system. As a result, the pattern corresponding to one micromirror is a 0.1 micron side, that is, a 100 nm square. However, when drawing a mask, the minimum design dimension is generally as small as 1 to 4 nm, which is called a minimum grid. Therefore, in order to realize a pattern shape far smaller than a mirror projection pattern having a side of 100 nm, the amount of light irradiated on the projected pattern is changed. For example, according to the above document, the minimum grid is made to correspond to 1.56 nm, which is 1/64 of 100 nm, by changing the light amount in 64 steps (using an intermediate light amount).
[0006]
As described above, in the conventional method using the intermediate light quantity and corresponding to the minimum grid having a size smaller than the reduced projection pattern of one micromirror, the deflection angle of each micromirror in the mirror device is controlled, and thus the projection is performed. The intensity of the laser beam is changed. In this regard, if exposure is performed so that the micromirror projected every 1.56 nm which is the minimum grid is moved (that is, scanning of the mask substrate), the scan speed is reduced to 1/64, and the number of scans Since the time is also increased by 64 times, the drawing time becomes extremely long as 64 × 64 = 4096 times. That is, using the intermediate light amount is indispensable for shortening the drawing time in the laser beam drawing apparatus.
[0007]
In addition, an excimer laser that performs a repetitive pulse operation of 2000 Hz is used for a laser device that is an ultraviolet light source in the conventional laser beam drawing apparatus, similarly to a normal exposure apparatus (generally called an excimer stepper). It is done. However, since the variation in pulse energy is large, the variation in energy is reduced by irradiating four pulses of laser light for exposure to the same pixel, which is called four-pass writing. Therefore, as the actual exposure processing speed, the projection image of the mirror device is moved at a repetition rate of 500 Hz (that is, 500 times per second).
[0008]
[Non-Patent Document 1]
Proceedings of SPIE, Vol.4186, PP.16-21
[0009]
[Patent Document 1]
U.S. Patent 6,428,940
[0010]
[Problems to be solved by the invention]
However, in the conventional method of controlling the mirror deflection angle in order to produce an intermediate light quantity, it is necessary to accurately control the voltage applied to each micromirror. However, in order to change the intermediate light amount to 64 steps as described above, it is necessary to control the voltage by finely dividing the voltage into 64 steps, and 0.0005 corresponding to the repetition rate of 2000 Hz of the excimer laser as the light source. It has been difficult to accurately control all the voltages of as many as one million micromirrors within at least a fraction of a short time in seconds. As a result, there are cases where the actually applied voltage does not have exactly 64 steps, and variation occurs, so that the amount of light can be substantially controlled by only a few steps.
[0011]
An object of the present invention is to provide a pattern drawing method and a pattern drawing apparatus that can use an intermediate light amount without being controlled using an intermediate value of a voltage applied to each micromirror.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the mirror device exposes the entire pattern projection area projected at a certain moment by overlapping a plurality of times. According to this, since it is possible to obtain gradations of light amounts corresponding to the number of times of overlapping, it is not necessary to perform intermediate value control of the deflection angle in each micromirror.
[0013]
In particular, by using a wavelength conversion solid-state laser, a microwave excitation excimer laser, or a copper vapor laser as a light source, a pulse operation can be performed at a high repetition rate of about 10,000 Hz in the ultraviolet region, as will be described later. The pattern generation speed with respect to can be increased to the number of frames of the mirror device itself. According to this, it is 20 times faster than 500 Hz in the case of an excimer laser used in a conventional laser beam drawing apparatus. Therefore, for example, even when reproducing 64 gradations equivalent to the conventional one without performing the intermediate value control of the deflection angle in each micromirror, the scan speed of the projection pattern is not limited to 1/64, but about 1/3.
[0014]
Further, if a mirror device having a frame number of about 30000 Hz is used and the laser of the light source is also operated at 30000 Hz, the intermediate value control of the deflection angle in each micromirror is not performed, and it is equivalent to the conventional laser beam drawing apparatus. Drawing speed can be obtained.
[0015]
That is, it is known that a wavelength conversion type solid-state laser can perform a pulse operation at a repetition rate up to about 1000 to 30000 Hz by an ultrasonic Q switch operation. On the other hand, it is also known that the number of repetitions can be freely set in a wide range of 100 to 100,000 Hz by repeatedly performing a pulse operation (but simple ON / OFF operation) of a microwave as a power source even in a microwave excitation excimer laser. Therefore, in the present invention, a wavelength conversion type solid laser or a microwave excitation excimer laser is used as the ultraviolet light source. On the other hand, a normal (that is, direct current pulse discharge type) excimer laser used as a light source of a conventional laser beam drawing apparatus has a repetition rate of usually only 100 to 1000 Hz, and is particularly developed as an exposure light source. Even in the high repetition type, the number of repetitions of about 4000 Hz is the limit.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
A first embodiment will be described with reference to FIGS. FIG. 1 is a configuration diagram of a pattern drawing apparatus 100 as a first embodiment of the present invention, and FIG. 2 is an explanatory diagram of a pattern drawing method by the pattern drawing apparatus 100.
[0018]
The pattern drawing apparatus 100 shown in FIG. 1 is roughly composed of a mask pattern projection unit 101, an XY stage 102, a mask pattern output apparatus 103, and a wavelength conversion type solid-state laser 104 that is an ultraviolet light source. The wavelength conversion type solid-state laser 104 uses the third harmonic of a YAG laser that performs a repetitive pulse operation at 10000 Hz, and a pulsed laser beam L1 having a wavelength of 355 nm is extracted. The laser light L1 enters the mask pattern projection unit 101, is reflected by the mirror 105, and enters the mirror device 106, which is a two-dimensional array of minute mirrors. The mirror device 106, here, 2048 × 512 (that is, about 1 million) micromirrors are arranged vertically and horizontally at a pitch of about 16 microns. In the mirror device 106, the deflection angle of each micromirror is controlled by the mask pattern data output device 103 at a frame rate of 10,000 Hz. In the present invention, however, the mirror device 106 is controlled only in two directions (that is, ON / OFF control). As a result, the laser beam L2 advances in the direction used for exposure. The laser light L2 travels through the lenses 107a and 107b and is transferred as a projection pattern 109 on the mask substrate 108. That is, the lenses 107a and 107b form a reduction projection optical system, and the surface of the mirror device 106 is reduced and projected onto the mask substrate 108 coated with the i-line resist. Further, the mask substrate 108 is placed on the XY stage 102, whereby the projection pattern 109 can be moved over the entire area of the mask substrate 108, and a pattern can be drawn on the entire surface of the mask substrate 108.
[0019]
In transferring the pattern on the mirror device 106 onto the mask substrate 108, the present invention uses a drawing method as shown in FIG. FIG. 2 shows, in time series, how the projection pattern 109 is moved in the X direction in FIG. In the pattern drawing apparatus 100, as described above, the pattern on the mirror device 106 is controlled with the number of frames of 10,000 Hz, so that a new pattern is projected onto the mask substrate 108 every 0.1 ms. 2 (a), (b), (c), (d), and (e), the positions of the projection pattern 109 at intervals of 0.1 ms (sequentially, 109a, 109b, 109c, 109d, 109e). That is, the pattern projected on the mask substrate 108 is moved by ¼ of the size of the projection pattern (width in the X direction) by the generation of the pulsed laser beam L1 every 0.1 ms. The projection pattern 109 is moved by moving the mask substrate 108 by the XY stage 102.
[0020]
As described above, in this embodiment, each projection pattern has a 3/4 area overlap between frames, so that the projection pattern overlaps the entire surface of the mask substrate 108 four times. Accordingly, four levels of gradation can be obtained. However, in the present embodiment, the case of four gradations is shown for ease of explanation, but in practice, it is preferable to perform about 50 gradations such that the areas of 49/50 overlap, for example, between frames. This is because the minimum grid can be reduced to about several nanometers.
[0021]
In this embodiment, since the number of repetitions of the wavelength conversion solid-state laser 104 that is a light source is 10,000 Hz, each generated pulse corresponds to each frame of the mirror device 106. Although it may be operated at a higher repetition rate, it is preferably an integer multiple of the number of frames of the mirror device 106. For example, when the wavelength conversion solid-state laser 104 is operated at 20000 Hz, it is only necessary to irradiate one frame of the mirror device 106 with two pulses of laser light. According to this, since a plurality of pulse lights are supplied to the same pattern, an adverse effect due to variations in pulse energy is mitigated (ie, averaged).
[0022]
Next, the movement in the Y direction of the projection pattern 109 in the pattern drawing method of the mask substrate 108 in the present embodiment shown in FIG. 1 will be described with reference to FIG. FIG. 3A shows only the outline of the projection pattern 109 shown in FIG. 1 for each frame. However, as shown in FIG. 2, since the projection patterns overlap between the frames, in FIG. 3, the four consecutive projection patterns 109f, 109g, 109h, and 109i are drawn slightly shifted in the Y direction. Actually, it may be the same position in the Y direction. When one scan is completed in the X direction when projecting onto the enlargement mask 110, the process steps once in the Y direction and scans again in the X direction. As a result, as shown in FIG. 3A, the pattern projected next to the projection pattern 109f is the projection pattern 109j, and is slightly overlapped with the end of 109f.
[0023]
On the other hand, as shown in FIG. 3B, the patterns to be projected next to the four projection patterns 109f, 109g, 109h, and 109i after one step may be projected so as to largely overlap. In other words, the projection patterns 109k, 109l, 109m, and 109n may be overlapped by 3/4. According to this, 3/4 overlap in the X direction and 3/4 overlap in the Y direction. As a result, when the entire surface of the mask substrate 108 is projected, the overlap occurs 16 times at all positions, resulting in 16 gradations. Can be issued. As described above, by overlapping in the two directions X and Y, abnormal exposure due to the stitching error after the step can be reduced.
[0024]
Next, a second embodiment of the present invention will be described with reference to FIG. A pattern drawing apparatus 200 of the present invention shown in FIG. 4 includes a mask pattern projection unit 101, a mask pattern output apparatus 103, and an ultraviolet light source, which are the same components as the pattern drawing apparatus 100 of the first embodiment shown in FIG. And a wavelength conversion type solid-state laser 104. However, instead of directly drawing a mask by the mask pattern projection unit 101, the intermediate mask 201 is drawn by a pattern, and this is masked on the mask substrate 204 placed on the XY stage 205 by the reduction projection optical system 202. An apparatus for forming the pattern 205. In this embodiment, the same mask pattern projection unit 101 as in the first embodiment is used and the drawing method as shown in FIG. 2 is used. As a result, the intermediate mask 201 is drawn at high speed. As a feature of the present embodiment, the mask pattern 205 that is actually transferred to the mask substrate 204 can be made dimensionally smaller than the intermediate mask 201 by about ¼. The configuration is suitable for.
[0025]
Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 5, the pattern drawing apparatus 300 of the present invention has a configuration similar to that of the pattern drawing apparatus 100 of the first embodiment shown in FIG. 1, but the wavelength conversion type solid-state laser device 304 used as a light source is a YAG laser. This is a device that generates the second harmonic. Therefore, the extracted laser beam L31 is a green laser beam having a wavelength of 532 nm. The laser beam L31 is reflected by the mirror 305, hits the mirror device 306, and the laser beam L32 used for exposure travels downward and enters the lens 307a. As a result, the laser beam L33 in the ultraviolet region having a wavelength of 266 nm, which is the second harmonic of the laser beam L31, is generated in order to condense on the wavelength conversion element 315. The laser beam L33 passes through the lenses 307b and 307c and strikes the projection pattern 309 of the mask substrate 312 coated with KrF resist. In the projection pattern 309, the pattern in the wavelength conversion element 315 is enlarged and projected, but the pattern of the mirror device 306 is reduced and projected in the wavelength conversion element 315. Therefore, the projection pattern 309 is a reduction projection of the pattern of the mirror device 306.
[0026]
As a feature of the present embodiment, there is an effect that the mirror device 306 is hardly deteriorated by using a laser device in the visible region as the wavelength conversion type solid-state laser device 304 which is a light source. That is, conventionally, as one of the problems of a laser beam drawing apparatus using a mirror device, the mirror device may be deteriorated in a short period of time by irradiation with ultraviolet laser light. On the other hand, in this embodiment, the mirror device 306 is hardly deteriorated.
[0027]
Incidentally, a copper vapor laser may be used in place of the wavelength conversion type solid-state laser device 304 which is the light source of the present embodiment. It is known that a copper vapor laser can generate laser light with a high average output at a wavelength of 510.6 nm with a high repetition rate of 5000 to 30000 Hz. Therefore, when this is used as a light source, the wavelength conversion element 315 can generate an ultraviolet laser beam L33 having a wavelength of 255.3 nm. Therefore, the mask substrate 312 coated with the KrF resist can be exposed more efficiently. That is, many KrF resists have the best characteristics at a wavelength of 248 nm of a KrF excimer laser, but the second harmonic of the copper vapor laser as in this example is more than the second harmonic of the YAG laser. This is because the wavelength is close to 248 nm.
[0028]
Next, another embodiment of the present invention will be described with reference to FIG.
[0029]
FIG. 6 is a configuration diagram of the pattern drawing apparatus 400 of the present invention as viewed from above.
[0030]
In the pattern drawing apparatus 400, two ultraviolet lasers are used as light sources, which are wavelength conversion type solid-state lasers 404a and 404b, respectively. Each of the wavelength conversion solid-state lasers 404a and 404b is configured to generate pulsed laser light having the same energy at a wavelength of 355 nm and a repetition rate of 10,000 Hz at the same timing by synchronous operation. The laser beam L41 extracted from the wavelength conversion type solid-state laser 404a is reflected by the mirror 405a and enters the beam splitter 410. On the other hand, the laser beam L42 extracted from the wavelength conversion solid-state laser 404b also enters the beam splitter 410. The beam splitter 410 has a reflectivity and a transmittance of approximately 50% with respect to 45-degree incidence of laser light having a wavelength of 355 nm. Therefore, both the laser beams L43 and L44 traveling from the beam splitter 410 have an average power. The laser beam L43 is supplied to the mask pattern projection unit 401a, and the laser beam L44 is reflected by the mirror 405b and then supplied to the mask pattern projection unit 401b. The structure of the mask pattern projection units 401a and 401b is the same as that of the mask pattern projection unit 101 of the first embodiment shown in FIG.
[0031]
On the other hand, the mask substrate 408 indicated by hatching drawn by the mask pattern projection units 401a and 401b is placed on the Y stage base 402a in the XY stage 402, and as indicated by an arrow 411, the mask substrate 408 is arranged in the Y direction. The scan moves. The Y stage base 402a is placed on the X stage base 402b and moves stepwise in the X direction as indicated by an arrow 412. That is, the entire surface of the mask substrate 408 can be drawn by the scanning movement of the Y stage base 402a and the step movement of the X stage base 402b.
[0032]
The feature of the present embodiment is that two pulse lasers (that is, wavelength conversion type solid-state lasers 404a and 404b) are used as an ultraviolet light source, and the extracted laser light is formed via a beam splitter (or half mirror). That is, two laser beams are used for exposure. As a result, since the pulse energy variation in the two pulse lasers can be averaged, the energy variation of the pulse laser light supplied to the two mask pattern projection units 401a and 401b is the wavelength conversion type solid-state laser 404a. , And the pulse energy variation of 404b is smaller. Therefore, more uniform exposure can be performed.
[0033]
In the present embodiment, two ultraviolet light sources and two mask pattern projection units are shown. However, the number of each may be larger, for example, both may be provided in units of four. In that case, three beam splitters are required, but this has the effect of further reducing pulse energy variations.
[0034]
Note that the pulse energy variation can be reduced because not only uniform exposure is possible, but conventionally, when the variation is large, multiple exposures are required, i.e., since multiple scans are performed at the same location, the total exposure time can be reduced. There is an effect that can solve the problem that the time is long.
[0035]
Next, two other embodiments relating to the pattern drawing apparatus of the present invention will be described with reference to FIGS.
[0036]
FIG. 7 is a configuration diagram of the pattern drawing device 500 as viewed from above, and FIG. 8 is a configuration diagram of the pattern drawing device 600 as viewed from above. Both embodiments show the configuration in the case where a plurality of light sources are used as in the embodiment shown in FIG. 6. In FIG. 7, when three light sources are used, FIG. In particular, the present invention relates to a method for synthesizing laser beams. The stage for driving the mask substrates 508 and 608 is the same as in FIG. 6, and the mask pattern projection units 501a, 501b, 501c, 601a, 601b, 601c, and 601d have the same structure as in FIG. Therefore, it is omitted here.
[0037]
In the pattern drawing apparatus 500 shown in FIG. 7, three pulse laser apparatuses 504a, 504b, and 504c are used as light sources.
[0038]
These are preferably a wavelength conversion type solid-state laser or a wavelength conversion type copper vapor laser. The laser beams L51, L52, and L53 in the ultraviolet region extracted from the pulse laser devices 504a, 504b, and 504c travel along the dotted line in the drawing. The laser beam L51 is reflected by the mirror 505a, enters the beam splitter 510a having a reflectance of 50%, and is divided into transmission and reflection in half. The laser beam L51 transmitted through the beam splitter 510a is incident on the beam splitter 510b having a transmittance of about 66.7%. As a result, approximately 33.3% (= 50% × 66.7%) of the original energy of the laser beam L51 advances toward the laser beam L54.
[0039]
Further, 50% of the original energy of the laser beam L51 reflected by the beam splitter 510a is reflected by the mirror 505b and then enters the beam splitter 510c having a reflectivity of 50%. On the other hand, about 16.7% (= 50% × 33.3%) of the original energy of the laser beam L51 reflected from the beam splitter 510b also enters the beam splitter 510c. As a result, the laser beam L51 traveling from the beam splitter 510c as shown in the right laser beam L55 in the drawing becomes 33.3% (= 16.7% × 50% + 50% × 50%) of the original energy.
[0040]
From the above, in all of the laser beams L54, L55, and L56, the laser beam L51 is included in about 33.3%. Similarly, the laser beams L52 and L53 are also included in about 33.3%. As a result, each pulse energy in the laser beams L54, L55, and L56 becomes an average value of each pulse energy of the laser beams L51, L52, and L53, so that variations in pulse energy are reduced.
[0041]
Next, the configuration of the pattern drawing apparatus 600 shown in FIG. 8 will be described. The laser beams L61, L63, and L64 extracted from the four pulse laser devices 604a, 604b, 604c, and 604d used in the pattern drawing apparatus 600 are a large number of mirrors 605a to 605h and four beams as shown in the figure. Splitting and combining are repeated by the splitters 610a, 610b, 610c, and 610d, and four laser beams L65, L66, L67, and L68 are generated. In this embodiment, the four beam splitters 610a, 610b, 610c, and 610d all have a reflectivity of 50% (transmittance of 50%), and the laser beams L61, L62, L63, and L64 are beams twice. Since it is incident on the splitter, everything becomes 1/4 energy and is distributed to four beams. Accordingly, the four laser beams L65, L66, L67, and L68 all include the laser beams L61, L62, L63, and L64 only with the same energy, that is, are averaged. Therefore, the laser beams L61, L62 are averaged. , L63, and L64, each energy variation is reduced to less than half.
[0042]
By the way, as in the embodiments shown in FIGS. 6, 7, and 8, the beam splitter used for splitting and synthesizing a plurality of laser beams extracted from a plurality of pulse laser devices is the above-described embodiment. In the example, a type that is divided into reflection and transmission having a specific ratio is used without depending on the polarization direction of the incident laser light. However, for example, a type having a greatly different reflectance (or transmittance) with respect to the polarization direction of the laser light may be used as generally called a polarization beam splitter. In particular, in the case of a wavelength conversion type laser, the extracted laser light is often linearly polarized light. Therefore, it is possible to combine two beams into one by a polarizing beam splitter.
[0043]
According to this, since one laser beam can be generated from two pulse laser apparatuses, even when there is one mask pattern projection unit, it is possible to reduce pulse energy variations. Similarly, two laser beams can be supplied to two mask pattern projection units by four pulse laser devices.
[0044]
【The invention's effect】
According to the pattern drawing apparatus of the present invention, gradation can be obtained without performing fine voltage control on the mirror device, so that not only high-precision and high-speed drawing can be performed, but also intermediate light quantity can be generated accurately and without malfunction.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a pattern drawing / shading apparatus 100 according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram of a pattern drawing method according to the present invention.
FIGS. 3A and 3B are diagrams illustrating an example of a pattern drawing method according to the present invention.
FIG. 4 is a configuration diagram of a pattern drawing apparatus 200 according to a second embodiment of the present invention.
FIG. 5 is a configuration diagram of a pattern drawing apparatus 300 according to a third embodiment of the present invention.
FIG. 6 is a configuration diagram of a pattern drawing apparatus 400 according to a fourth embodiment of the present invention.
FIG. 7 is a configuration diagram of a pattern drawing apparatus 500 according to a fifth embodiment of the present invention.
FIG. 8 is a configuration diagram of a pattern drawing apparatus 600 according to a sixth embodiment of the present invention.
[Explanation of symbols]
100, 200, 300, 400, 500, 600 Pattern drawing apparatus
101 Mask pattern projection unit
102, 302, 402 XY stage
103 Mask pattern data output device
104, 304, 404a, 404b Wavelength conversion type solid-state laser
105 mirror
106,306 Mirror device
107a, 107b, 307a, 307b, 307c Lens
108, 204, 312, 408, 508, 608 Mask substrate
109, 109a, 109b, 109c, 109d, 109e, 109f, 109g, 109h, 109i, 109j, 109k, 109l, 109m, 109n, 309 Projection pattern
201 Intermediate mask
202 Reduction projection optical system
203 stages
205 Mask pattern
L1, L2, L31, L32, L33 Laser light

Claims (6)

Exposure light from a light source is incident on a mirror device that includes two-dimensionally arranged micromirrors and the pattern is controlled at a predetermined frame rate, and a pattern is formed on the substrate using a projection pattern output from the mirror device. In the pattern drawing method for drawing, a pulse operation is performed as the light source at a repetition number equal to or higher than the frame speed of the mirror device, and a laser for supplying exposure light to the mirror device is prepared. By irradiating the mirror device with laser light by performing pulse operation with a number , the micro mirror of the mirror device is controlled to be turned on / off at the predetermined frame speed to directly or reduce the projection pattern output from the mirror device. the projection to substantially the entire surface of the pattern projection region on the substrate, optionally A plurality of times determined in accordance with the number of gradations, and exposed by overlap whereby, pattern exposure method, characterized in that can realize an intermediate light amount corresponding to the number of the gradation by the on-off control of the micromirrors .   2. The pattern according to claim 1, wherein the light source is a wavelength conversion solid-state laser or a microwave-excited excimer laser in which the number of repetitions of the pulse operation in the light source is an integral multiple of the frame speed of the mirror device. Drawing method.   2. The pattern drawing method according to claim 1, wherein a second harmonic of a solid laser or a copper vapor laser is used as the light source, and the projection light is wavelength-converted and projected onto the substrate. A mirror device that includes two-dimensionally arranged micromirrors and that controls the on / off of the micromirrors at a predetermined frame rate, and a pulse operation with a repetition rate equal to or greater than the frame rate of the mirror devices. By using a light source for supplying exposure light to the mirror device, a mask pattern drawing substrate, a moving mechanism for moving the substrate in the X and Y directions, and a projection pattern output from the mirror device. and means for projecting directly or shrink the substrate, the projection pattern on the substantially entire surface of the pattern projection region on the substrate, a plurality of times defined in accordance with the desired number of gradations, thereby overlapping look including a controller for exposure, thereby, an intermediate amount of light corresponding to the number of the gradation by the on-off control of the micromirrors Pattern writing apparatus characterized by be present. As the light source, the pattern of claim 4, wherein the number of repetitions of the pulse operation in the light source using frame rate of the wavelength-conversion solid-state laser or microwave excitation excimer laser is an integer multiple of said mirror device Drawing device.   5. The pattern writing apparatus according to claim 4, further comprising a wavelength conversion element that uses a second harmonic of a solid-state laser or a copper vapor laser as the light source and converts the wavelength of the projection light.

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