JP2002367900A - Exposure apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure apparatus and method for exposure in a shape coincident with a desired pattern by correcting a distortion curve by an optical system and perform exposure with an irradiating intensity uniform in a space and time. SOLUTION: The exposure apparatus comprises a light source means 1 for supplying substantially parallel luminous fluxes, many infinitesimal mirrors capable of changing directions independently from each other, and a space optical modulation means 2 for reflecting the luminous fluxes from the means 1 via the many mirrors to deflect the fluxes, in such a manner that an image is formed on an article 5 to be exposed by the fluxes reflected and deflected by the means 2 and the article 4 is exposed. The apparatus comprises a photodetecting means 81 disposed near the article to be exposed, and a control means 9 for controlling directions of the mirrors of the means based on an output of the means 81.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the exposure of a circuit pattern to a silicon wafer or printed circuit board coated with a photoresist, a bar code having information such as a date and a serial number on a metal product, a silicon wafer or a resin product. The present invention relates to an exposure apparatus and an exposure method for performing exposure drawing without using a mask pattern, which can be used for marking a two-dimensional code.

[0002]

2. Description of the Related Art As a conventional exposure apparatus, for example,
No. 112579. Hereinafter, FIG.
This will be described with reference to FIG.

In FIG. 27, 1 is a light source, 2 is a digital micromirror device (hereinafter referred to as "DMD"), 3 is an optical absorber that absorbs light reflected on the DMD, 4 is a lens, and 5 is a lens. A photoresist coated wafer, 6 is a support table, and 7 is an XY stage.

In the above configuration, pattern data such as a figure formed by CAD is input to the DMD 2 as an electric signal. Each of the plurality of micro mirrors of the DMD 2 tilts according to the input electric signal. When light from the light source 1 is incident on the plurality of micromirrors, an image similar to a figure composed of tilted micromirrors is exposed on the wafer 5 through the lens 4. The wafer 5 is moved to the next position by the XY stage 7, and the same operation is performed to perform the next exposure.

[0005]

However, the prior art described in Japanese Patent Application Laid-Open No. H10-112579 has a problem in that the light source is not ideally parallel light and distortion due to an optical system such as lens aberration causes a problem on the wafer. The resulting image is distorted compared to the desired pattern.

Further, since the amount of light from the light source is not spatially uniform and the amount of light is concentrated near the optical axis by the lens, the amount of light irradiated on the wafer is uneven. Therefore, there is a problem in that the time required for exposure differs depending on the irradiated portion, and a portion where the exposure is partially overexposed occurs. Further, when the light amount of the light source fluctuates with time due to the influence of the ambient temperature or the aging of the light source, there is a problem that overexposure or incomplete exposure occurs as a whole.

Accordingly, the present invention provides an exposure apparatus and an exposure method capable of correcting distortion caused by an optical system, performing exposure with a shape conforming to a desired pattern, and performing exposure with uniform irradiation intensity both spatially and temporally. That is.

[0008]

An exposure apparatus according to the present invention has a light source means for supplying a substantially parallel light beam, and a large number of micromirrors capable of changing directions independently of each other. Consisting of spatial light modulating means for reflecting and deflecting the light flux from the light source means by each of the micro mirrors,
An exposure apparatus for forming an image on an object to be exposed by a light beam reflected and deflected by the spatial light modulator and exposing the object to be exposed, comprising: (1) a light detector arranged near the object to be exposed; Control means for controlling the direction of each of the micromirrors of the spatial light modulation means based on the output of the detection means.When the present exposure apparatus is used, image distortion due to the optical system is reduced. The exposure can be performed in a shape conforming to the desired pattern after the correction, and the exposure can be performed with a uniform irradiation intensity, so that no exposure unevenness occurs.

(2) A dummy optical system provided in a traveling direction of a light beam reflected in a direction not contributing to exposure by the spatial light modulating means; a light detecting means arranged in the dummy optical system; Control means for controlling the direction of each of the micromirrors of the spatial light modulation means based on the output, and using the present exposure apparatus, corrects image distortion due to the optical system. Exposure can be performed in a shape that matches a desired pattern. In addition, exposure can be performed with a uniform irradiation intensity, and no exposure unevenness occurs. Furthermore, since the fluctuation of the light amount can be always detected during the exposure, the light amount of the light source is
Exposure can be performed with a uniform irradiation intensity even when it fluctuates due to the influence of the ambient temperature or aging of the light source.

Further, according to the exposure method of the present invention, the plurality of micromirrors of the spatial light modulator having a plurality of micromirrors capable of changing directions of substantially parallel light beams supplied by the light source means independently of each other. In an exposure method for forming an image on an object to be exposed while exposing the object to be exposed in the shape of the image, wherein: (1) distortion data of an image on the object to be calculated obtained by calculation; Or changing and controlling the micro mirror to be tilted in the spatial light modulator based on distortion data of an image on the object to be exposed obtained by measurement by a light detector provided near the object to be exposed. When this exposure method is used, image distortion due to the optical system can be corrected, and exposure can be performed in a shape that matches a desired pattern.

(2) On the dummy optical system obtained by measurement by the light detecting means provided on the dummy optical system through which the light not directed to the object to be exposed among the reflected light from the spatial light modulating means passes. Based on the distortion data of the image, the micromirror to be tilted in the spatial light modulator is changed and controlled, and using this exposure method, the distortion of the image due to the optical system is corrected, and the desired pattern is corrected. Exposure can be carried out in a shape that matches.

(3) Based on distortion data of an image on the object to be exposed obtained by calculation or light amount distribution data of an image on the object to be exposed obtained by measurement by a light detecting means provided near the object to be exposed. The micromirrors in the spatial light modulating means are repeatedly tilted by PWM control. When the present exposure method is used, exposure can be performed with a uniform irradiation intensity and no exposure unevenness occurs.

(4) An image on the dummy optical system obtained by measurement by the light detecting means provided on the dummy optical system through which the light not directed toward the object to be exposed among the reflected light from the spatial light modulating means passes. Characterized in that the micromirrors in the spatial light modulating means are repeatedly tilted by PWM control based on the light amount data of the spatial light modulating means. Absent. Further, since the fluctuation of the light amount can always be detected even during the exposure, even when the light amount of the light source fluctuates due to the influence of the ambient temperature or the aging of the light source, the exposure can be performed with a uniform irradiation intensity.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An exposure apparatus according to a first embodiment of the present invention will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes light source means for supplying a substantially parallel light beam. 2 is a DMD, 3 is an optical absorber, 4 is a lens system, 5 is a wafer coated with photoresist, 6 is a support table for supporting the wafer 5, and 7 is X-ray.
Y stage, 71 and 72 are motor encoder signals of XY stage, 81 is photodiode, 9 is control means,
Reference numeral 10 denotes a recording unit.

By using a laser light source as the light source means 1, a bar code or a two-dimensional code can be marked on a metal product, a silicon wafer or a resin product. As a laser light source, a He-Cd laser,
Ar laser or gas laser of excimer laser, Y
A harmonic laser light source that emits a laser beam having a wavelength of a harmonic component can be used in combination with a solid laser such as an AG laser, a YLF laser, a fiber laser or a semiconductor laser, a liquid laser such as a dye laser, and a nonlinear optical crystal. By using a lamp light source as the light source means 1, it is possible to expose an irradiation target object coated with a photoresist. As the lamp light source, an ultraviolet light source that emits ultraviolet light that is easily exposed to the photoresist is preferable. By adding a collimating lens after these light sources, the light beams can be made closer to parallel.

The DMD 2 is an example of a spatial light modulator, and has a large number of micro mirrors whose directions can be changed independently of each other. Each of the micro mirrors reflects a light beam from the light source 1. And deflect. DMD2
Is composed of a large number of micromirrors (fine reflection mirrors) arranged in a grid pattern. The DMD 2 is an integrated micro-mirror, and the angle (ie, direction) of the micro-mirror changes due to electrostatic attraction between an electrode provided for each micro-mirror and the micro-mirror. That is, the orientation of each micromirror is configured to be individually driven and controlled. Even if it has a structure different from that of the DMD 2 or a device using other force such as a magnetic force, as long as it is composed of a large number of elements capable of independently changing the traveling direction of light, spatial light It can be used as modulation means.

The light absorber 3 absorbs light reflected by the spatial light modulator in a direction that does not contribute to exposure.

When a reduction lens system for reducing the light beam from the spatial light modulator and irradiating the object to be exposed is used as the lens system 4, an image smaller than the size of the spatial light modulator can be formed on the object to be exposed. . If a magnifying lens system for expanding the light beam from the spatial light modulator and irradiating the object to be exposed is used as the lens system 4, an image larger than the size of the spatial light modulator can be formed on the object to be exposed. The wafer 5 is an example of an object to be exposed to which a light beam reflected and deflected by the spatial light modulator is irradiated. In addition, as the object to be exposed, a metal, resin, organic or metal thin film-deposited glass substrate, a printed substrate coated with a photoresist, or the like is used.

The photodiode 81 is an example of a light detecting means arranged near the object to be exposed. As the light detecting means, another semiconductor device element such as a phototransistor may be used. Further, a phototransistor array or a photodiode array arranged in an array may be used.
Furthermore, a CCD or MOS type photodetection device may be used. The mounting position of the light detecting means is preferably a position that does not interfere with the object 5 and that can be moved at the same height as the object 5. In FIG. 1, a photodiode 81 is fixed to a support table 6 via a support 801.

The control means 9 controls the direction of each micro mirror of the spatial light modulation means based on the output of the photodiode 81. The recording means 10 is provided in the control means 9 and records a signal detected by the photodiode 81 or data calculated by the control means. As the control means 9, a computer can be used, and the recording means 1 in the control means is used.
As 0, a semiconductor memory such as a RAM or a magnetic memory such as a hard disk can be used.

An exposure method for exposing a wafer by correcting image distortion due to the optical system using the exposure apparatus having the above configuration will be described with reference to the flowchart of FIG.

(Step 201) In a state where the wafer 5 is not supplied onto the support table 6, light is emitted from the light source 1 to the DMD 2.

(Step 202) Photodiode 81
Is moved to an arbitrary XY coordinate on the expected wafer supply position and stopped.

(Step 203) The micromirrors of the DMD 2 are scanned one by one, and a micromirror that maximizes the detection signal of the photodiode 81 is specified. That is, the micro mirror that reflects light to the position where the photodiode 81 is stopped is specified.

(Step 204) The XY stage 7 is sequentially moved, and the operations of steps 202 to 203 are repeated to move the photodiode 81 to the respective XY positions.
The micro mirror that reflects light is specified, and the micro mirror of the DMD 2 corresponding to the XY coordinate position of the wafer supply scheduled position is measured.

(Step 205) From the relationship between the XY coordinates of the expected wafer supply position obtained by the above measurement and the corresponding micro mirror of the DMD 2, the distortion data of the image is created by the control means 9 and The information is recorded in the recording means 10.

(Step 206) The irradiation of the light from the light source 1 is stopped, and the wafer is supplied onto the support table 6.

(Step 207) The data of the pattern to be actually exposed is input to the control means 9.

(Step 208) The control means 9 creates corrected pattern data based on the distortion data of the image recorded in advance and inputs it to the DMD 2. Therefore, the figure constituted by the tilted minute mirror has a shape different from the command pattern data.

(Step 209) Light from the light source 1 is irradiated again. An image of light reflected by the micro mirror of the DMD 2 tilted according to the corrected pattern data is generated on the wafer. Therefore, it is possible to correct the image distortion due to the light source and the lens aberration, and to expose a pattern shape that matches the commanded pattern shape.

Another exposure method for correcting image distortion due to the optical system using the exposure apparatus having the above configuration will be described with reference to the flowchart of FIG.

(Step 301) In the state where a wafer is not supplied onto the support table 6, pseudo pattern data is input to the control means. This pseudo pattern is a pattern for measuring image distortion, and may be a simple geometric pattern as shown in FIG.

(Step 302) The control means tilts each micro mirror of the DMD 2 in accordance with the input pseudo pattern data. Therefore, the DMD 2 has a shape similar to the pseudo pattern as shown in FIG. 5, and the mirror is inclined.

(Step 303) DMD from the light source 1
Irradiate 2 One of the light beams reflected by the tilted micromirror travels to the wafer supply scheduled position on the support table 6, and the other travels toward the optical absorber 3. FIG. 6 shows an image by the DMD 2 generated at the wafer supply scheduled position.

(Step 304) Photodiode 81
By scanning the XY stage 7 on which
A change in the amount of light on the horizontal plane at the wafer supply scheduled position is measured.

(Step 305) Photodiode 81
The control means calculates the shape of the image generated above the wafer supply position on the basis of the signal from the controller.

(Step 306) The control means 9 compares the input pseudo pattern data with the shape of the image detected by the light detecting means (photodiode) 81, creates distortion data of the image, and records it on the recording means 10. I do.

(Step 307) The irradiation of the light from the light source 1 is stopped, and the wafer is supplied onto the support table 6.

(Step 308) The data of the pattern to be actually exposed is input to the control means 9.

(Step 309) The control means creates corrected pattern data based on the distortion data of the recorded image and inputs it to the DMD2. The mirror of the DMD 2 is tilted in a shape different from the command pattern data input by the corrected pattern data. (Step 310) The light from the light source 1 is irradiated again. An image of light reflected by the micro mirror of the DMD 2 tilted according to the corrected pattern data is generated on the wafer. Therefore, it is possible to correct the image distortion due to the light source and the lens aberration, and to expose a pattern shape that matches the commanded pattern shape.

In any of the above exposure methods, when the wafer is repeatedly exposed, even if the input pattern data is changed, the above-described process of creating the distortion data only needs to be performed once.
Correction pattern data may be generated each time based on the distortion data recorded in the recording means 10.

In any of the above exposure methods, when a two-dimensionally arranged light detecting element such as a CCD 82 is used as the light detecting means, it is not necessary to move the XY stage 7 in the process of creating image distortion data. There is an advantage.

In the above-described exposure method, the shape of the image is detected by using the light detecting means attached to the exposure apparatus to generate the distortion data. However, the distortion data of the image generated by the optical design value of the exposure apparatus or the simulation result is obtained. If
Exposure can be performed by creating correction pattern data based on the distortion data. In this case, no light detection means is required.

An exposure method for performing exposure by correcting unevenness in the amount of light using the exposure apparatus having the above configuration will be described with reference to the flowchart of FIG.

(Step 701) Light is irradiated from the light source 1 to the DMD 2 in a state where the wafer is not supplied onto the support table 6.

(Step 702) The control means 9 tilts all the micro mirrors of the DMD 2 so that the reflected light is directed to the wafer supply scheduled position.

(Step 703) Photodiode 81
By scanning the XY stage 7 on which
The light amount of the image generated at the wafer supply scheduled position is measured. The signal measured by the photodiode 81 is input to the control means 9 and the distribution of the light amount is measured.

(Step 704) The control means 9 creates light amount correction data based on the detected light amount distribution.

The light quantity correction data is data in which a portion having a large light quantity is small and a portion having a small light quantity is weighted in a large amount. In accordance with the light quantity correction data, the control means 9 determines the tilting time of each micro mirror of the DMD 2. Is subjected to PWM control. Specifically, the micromirror that reflects on the portion where the amount of light is small, and the micromirror that reflects on the portion where the amount of light is small so that the time inclined in the wafer installation direction becomes short,
The control means 9 performs the PWM control of the DMD 2 so that the time inclined in the wafer installation direction becomes longer.

(Step 705) The irradiation of the light from the light source 1 is stopped, and the wafer is supplied onto the support table 6.

(Step 706) Command pattern data to be actually exposed is input to the control means 9.

(Step 707) The control means calculates the AND of the command pattern data and the light quantity correction data, and the micro mirror of the DMD 2 corresponding to the negative part of the command pattern is tilted toward the optical absorber 3 and stopped. The micro mirror corresponding to the positive portion continues to tilt by PWM control.

(Step 708) Light from the light source 1 is irradiated again. An image of light reflected by the micro mirror of the DMD 2 that tilts with the corrected pulse width is generated on the wafer 5. Therefore, it is possible to correct unevenness in the light amount of the image due to the light source and the lens system, and to expose the pattern with a uniform light amount.

When the wafer is repeatedly exposed in the above exposure method, the measurement of the light quantity distribution of the image only needs to be performed once.
Thereafter, exposure may be performed based on the light quantity correction data recorded in the recording means 10 in the control means 9.

In the above exposure method, when a two-dimensionally arranged photodetector such as a CCD 82 is used as the photodetector, the XY stage 7 is used in the process of measuring the light quantity distribution of the image.
There is an advantage that there is no need to move the.

In the above-described exposure method, the light amount distribution is detected by using the light detecting means attached to the exposure device to generate the light amount correction data. Is obtained, light amount correction data is created based on the light amount distribution data, and exposure can be performed. In this case, no light detection means is required.

An exposure apparatus according to a second embodiment of the present invention will be described with reference to FIG.

In FIG. 8, the main difference from the first embodiment shown in FIG. 1 is that the dummy optical system 11 is used instead of the optical absorber in the traveling direction of light reflected by the spatial light modulator in a direction not contributing to exposure. And a photodetector (CCD) 82 is disposed in the dummy optical system 11. The dummy optical system 11 is preferably an optical unit equivalent to the optical unit provided between the spatial light modulator 2 and the object to be exposed. 12
Is a dummy lens system equivalent to the lens system 4 provided between the spatial light modulator 2 and the object to be exposed.

It is preferable that the light detecting means 82 is arranged at a position in the dummy optical system 11 corresponding to the installation position of the object to be exposed. Light detection means 8 arranged in dummy optical system 11
2 does not need to move because it does not interfere with the object to be exposed. Other semiconductor device elements such as a photodiode and a phototransistor may be used as the light detecting means. Further, a phototransistor array or a photodiode array arranged in an array may be used. further,
A CCD or MOS-type distortion-type light detection device may be used. However, in order to use the light detecting means without scanning, it is preferable to use a two-dimensionally arranged phototransistor array, photodiode array, CCD or MOS type light detecting device. In FIG. 8, two-dimensionally arranged CCDs 82 are used as light detecting means. 13
Is an openable / closable shutter provided between the spatial light modulator 2 and the object to be exposed.

An exposure method for correcting and correcting image distortion due to the optical system using the exposure apparatus having the above configuration will be described with reference to the flowchart of FIG.

(Step 901) Light is emitted from the light source 1 to the DMD 2 with the shutter 13 closed.

(Step 902) Only one micro mirror of the DMD 2 is tilted.

(Step 903) The position of the pixel of the CCD 82 at which the amount of received light changes due to the tilt of the micro mirror of the DMD 2 is detected.

(Step 904) DM to be tilted sequentially
The micromirror D2 is scanned to detect the position of the pixel of the CCD 82 where the amount of received light changes at that time.

(Step 905) The control means 9 compares the position of the tilted micromirror with the position of the pixel of the light detecting means (CCD) 82 in which the amount of received light has changed, and creates image distortion data. Is recorded in the recording means 10.

(Step 906) Command pattern data to be actually exposed is input to the control means 9.

(Step 907) The control means 9 creates corrected pattern data from the command pattern data,
Input to MD2.

(Step 908) The shutter 13 is opened. DM tilted according to the corrected pattern data
An image of the light reflected by the micromirror D2 is formed on the wafer 5. Therefore, it is possible to correct the image distortion due to the light source and the lens aberration, and to expose a pattern shape that matches the commanded pattern shape.

Another exposure method for correcting image distortion caused by the optical system using the exposure apparatus having the above configuration will be described with reference to the flowchart of FIG.

(Step 1001) With the shutter 13 closed, command pattern data to be exposed is input to the control means 9.

(Step 1002) The control means 9 tilts the micro mirror of the DMD 2 according to the command pattern.

(Step 1003) DMD 2 from light source 1
Is irradiated with light. The light reflected by the micromirror tilted to one side goes to the wafer supply position on the support table 6, and the light deflected by the micromirror tilted to the other goes to the dummy optical system 11.

(Step 1004) The light heading for the dummy optical system 11 passes through the dummy lens system 12, and the image of the DMD 2 is placed on the CCD 82 arranged at a position on the dummy optical system 11 equivalent to the expected wafer supply position. To form CCD
The DMD2 image formed on the image 82 has a shape obtained by reversing the negative / positive of the DMD2 image generated at the wafer supply scheduled position.

(Step 1005) The control means 9 compares the input pattern data with the shape of the image detected by the light detecting means (CCD) 82, creates distortion data of the image, and records it on the recording means 10.

(Step 1006) Command pattern data to be actually exposed is input to the control means 9.

(Step 1007) The control means 9 creates corrected pattern data from the command pattern data,
Input to DMD2.

(Step 1008) The shutter 13 is opened. D tilted according to the corrected pattern data
An image of light reflected by the micromirrors of the MD2 is generated on the wafer. Therefore, it is possible to correct the image distortion due to the light source and the lens aberration, and to expose a pattern shape that matches the commanded pattern shape.

In any of the above exposure methods, when the object to be exposed is repeatedly exposed, steps 1002 to 10
Step 04 may be performed only once, and correction pattern data may be created each time based on the distortion data recorded in the recording unit 10. By providing the shutter 13, step 1
Since the object to be exposed can be supplied to the exposure position during the operations of 001 to 1005, the working time can be reduced.

An exposure method for performing exposure by correcting unevenness in the amount of light using the exposure apparatus having the above configuration will be described with reference to the flowchart of FIG.

(Step 1101) With the shutter 13 closed, the DMD 2 from the light source 1 is irradiated with light.

(Step 1102) By the control means 9,
All the micro mirrors of the DMD 2 are tilted so that the reflected light goes to the dummy optical system 11.

(Step 1103) The CCD 82 measures the amount of light received from each pixel. (Step 1104) The control means 9 obtains the light quantity distribution based on the signal measured by the CCD 82. The light quantity distribution measured by the CCD 82 on the dummy optical system is equivalent to the light quantity distribution generated on the wafer.

(Step 1105) The control means 9 creates light quantity correction data based on the detected light quantity distribution and records it in the recording means 10. The light amount correction data is data in which a portion with a large light amount is small and a portion with a small light amount is weighted with a large amount. In accordance with the light amount correction data, the control means 9 determines the tilting time of each micro mirror of the DMD 2. PWM control is performed. Specifically, the micromirror that reflects on the portion where the amount of light is small, the time when the micromirror that reflects on the portion where the amount of light is small is short The control device 9 performs PWM control of the DMD 2 so as to be longer.

(Step 1106) Command data of a pattern to be actually exposed is input to the control means 9.

(Step 1107) The control means 9 calculates an AND of the command pattern data and the light quantity correction data, and
The micro mirror of the DMD 2 corresponding to the negative portion of the command pattern is tilted toward the dummy optical system 11 and stopped, and the micro mirror corresponding to the positive portion continues to tilt by PWM control.

(Step 1108) The shutter 13 is opened. An image of light reflected by the micro mirror of the DMD 2 that tilts with the corrected pulse width is generated on the wafer 5. Therefore, it is possible to correct unevenness in the light amount of the image due to the light source and the lens system, and to expose the pattern with a uniform light amount.

Further, since the temporal change of the light amount can be measured in real time by the CCD 82 even during the exposure, the CCD 82
By feeding back the signal of the light amount obtained from the control unit 9 to the control means 9, fluctuations in the light amount due to aging of the light source 1 and the like can be corrected, and exposure can always be performed with uniform irradiation intensity.

In the case of repeatedly performing exposure in the above exposure method, steps 1101 to 1105 may be performed once.
Thereafter, exposure may be performed based on the light quantity correction data recorded in the recording means 10 in the control means 9.

[0090]

[Embodiment 1] An embodiment of the exposure apparatus shown in FIG. 1 will be described.

As the object to be exposed, a silicon wafer 5 coated with a photoresist was used. A collimator lens was used as the light source 1 and a collimator lens was used to convert the light into parallel light. The DMD 2 used as the spatial light modulator has a height of 480
And 600 horizontal micromirrors. Between the DMD and the silicon wafer 5, a reduction lens 4 for reducing the size by half
Was placed.

First, for comparison, exposure was performed using the exposure apparatus shown in FIG. 1 by a conventional method in which neither distortion correction nor light amount correction was performed. A grid pattern having a line width of 150 μm as shown in FIG. 12 was input to the control means 9 and exposed for 3 seconds. DM
The micromirror D2 was tilted at a pulse width of 50% and a period of 60 Hz. As a result, the wafer was exposed as shown in FIG. The maximum distortion of the command pattern and the actually exposed pattern was 50 μm. In addition, overexposure occurred at the center of the pattern, and underexposure occurred at the periphery of the pattern. Next,
Exposure for correcting image distortion was performed by an exposure method according to the flowchart of FIG.

The XY stage 7 was moved as shown in FIG. 14, and the photodiode 81 was stopped at 24 positions ax on the expected wafer supply position as shown in FIG. The coordinates of the stop position of the photodiode 81 were obtained from the motor encoder signals 71 and 72 of the XY stage 7. DM
By scanning the micromirrors of D2 one by one, the micromirrors that reflect light to the position of the photodiode 81 shown in FIG. 14 were specified. Based on the data at the 24 locations, the image distortion data was created by the control means 9 and recorded in the memory 10 in the control means 9.

The control means 9 creates corrected pattern data from the input pattern shown in FIG. 12 based on the image distortion data, inputs the corrected pattern data to the DMD 2, and performs exposure. As a result, the wafer was exposed as shown in FIG. The distortion between the command pattern and the actually exposed pattern could be suppressed to 7 μm or less.

Further, as shown in the flow of FIG. 17, an exposure method for correcting the amount of light was simultaneously performed. Photodiode 81
Is scanned continuously in the X-axis direction and at 100 μm intervals in the Y-axis direction, thereby measuring the light amount distribution of the image generated at the wafer supply scheduled position.

As a result of measuring the distribution of the light amount, the central portion had 3.2 times the light amount as compared with the peripheral portion. Therefore, based on the detected light amount distribution, the light amount correction data is created by the control means 9. The weight of the central part where the amount of light is large is 3.125.
(= 10 / 3.2), the weight of the peripheral portion where the amount of light was small became 10. The data in the Y-axis direction was interpolated using an appropriate function (here, a spline function was used). According to the light quantity interpolation data, a weight 10
Are always tilted (= pulse width 100%) so as to face the wafer, and the micromirror at the center with a weight of 3.125 has a pulse width of 31.25% and a period of 6
Tilt at 0 Hz. As a result of exposure for 3 seconds, the wafer was uniformly exposed over the entire pattern as shown in FIG.

Embodiment 2 The results of the embodiment relating to the exposure apparatus shown in FIG. 8 will be described.

For the object to be exposed, a photoresist is applied to about 0.
Using chrome-deposited glass coated 8 μm, line width 150
A μm pattern was exposed. A parallel light was created by using a mercury lamp as a light source 1 and a collimator lens. The DMD 2 used as the spatial light modulator has a length of 480
And 600 horizontal micromirrors. A two-dimensional code of one cell is formed by a total of 100 micromirrors, 10 in each of the vertical and horizontal sides of the DMD, and a 20 × 20 cell and a 3.4 mm square two-dimensional code are formed by 200 × 200, a total of 4000 micromirrors. Formed on DMD. Between the DMD and the chromium-deposited glass 52, a reduction mirror 4 that reduces the size by half
Was placed.

First, for comparison, exposure was performed using the exposure apparatus shown in FIG. 8 by a conventional method in which neither distortion correction nor light amount correction was performed. The exposure time was 1 second, during which the micro mirror of DMD2 was tilted with a pulse width of 50% and a period of 60 Hz. FIG.
A two-dimensional code command pattern as described above was input to the control means 9 to perform exposure. FIG. 20 shows the exposure result. Overexposure occurred at the center of the pattern, and underexposure occurred at the periphery of the pattern. Since the two-dimensional code in FIG. 20 was insufficient at the peripheral portion, the code could not be read by the two-dimensional code reader. The distortion between the command pattern 2 and the actually exposed pattern was 50 μm at the maximum.

Next, exposure for correcting unevenness in the light amount of the image was performed by the exposure method according to the flowchart of FIG. CCD
As a result of measuring the distribution of the light amount at 82, the central portion had three times the light amount as compared with the peripheral portion. Therefore, based on the detected light amount distribution, the light amount correction data is created by the control means 9. The weight of the central part where the amount of light is large is 3.3 (= 10 /
3), the weight of the peripheral portion where the light quantity was small was 10; According to the light quantity interpolation data, the micromirrors at the periphery of weighting 10 are always tilted (= pulse width 100%) so as to face the chromium-deposited glass, and the small mirror at the center of weighting 3.125 has a pulse width of 31.25. % And a cycle of 60 Hz. The command pattern data was input to the control means 9, and the AND of the command pattern data and the light quantity correction data was calculated. The control means 9 inputs the result of the AND operation to the DMD 2. Therefore, the micro mirror of the DMD 2 corresponding to the negative portion of the command pattern tilted toward the dummy optical system 11 and stopped, and the micro mirror corresponding to the positive portion continued tilting by PWM control. Exposure was performed for 3 seconds in this state. As a result, a uniform two-dimensional code could be exposed as a whole as shown in FIG. When the two-dimensional code was read by a two-dimensional code reader, the code could be read at an error rate of 20%.

Further, as shown in the flow of FIG. 22, an exposure method for correcting image distortion was performed at the same time. As a result, FIG.
Exposure is uniform over the entire pattern as shown in 3,
In addition, a two-dimensional code without distortion could be created. When this two-dimensional code was read by a two-dimensional code reader, it became possible to read with a high accuracy of an error rate of 5% or less.

The mercury lamp used as the light source 1 in FIG.
When used for a long period of time, it changes over time as shown in FIG. Therefore, as shown in FIG. 25, the light amount signal measured by the CCD 2 is fed back to the mercury lamp power supply via the control means 9 so that the light amount change of the light source 1 during exposure becomes constant as shown in FIG. By keeping the light amount of the light source 1 constant,
The exposure quality did not change even after exposure to 00H.

[0103]

As described above, when the exposure method of the present invention is used, image distortion due to the optical system can be corrected, and exposure can be performed in a shape that matches a desired pattern. further,
Exposure can be performed with uniform irradiation intensity, and no exposure unevenness occurs. In addition, since the fluctuation of the light amount can always be detected even during the exposure, even when the light amount of the light source fluctuates due to the influence of the ambient temperature or the aging of the light source, the exposure can be performed with a uniform irradiation intensity.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an exposure method according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing an exposure method according to the first embodiment of the present invention.

FIG. 4 Pseudo-pattern for measuring image distortion

FIG. 5 shows the shape of a DMD due to the inclination of a micro mirror when a pseudo pattern is input.

FIG. 6 is an image by DMD2 generated at a scheduled wafer flooding position.

FIG. 7 is a flowchart showing an exposure method according to the first embodiment of the present invention.

FIG. 8 is a schematic view showing an exposure apparatus according to a second embodiment of the present invention.

FIG. 9 is a flowchart showing an exposure method according to a second embodiment of the present invention.

FIG. 10 is a flowchart illustrating an exposure method according to a second embodiment of the present invention.

FIG. 11 is a flowchart showing an exposure method according to a second embodiment of the present invention.

FIG. 12 is a diagram illustrating an example of an input pattern according to the first embodiment.

FIG. 13 is a view showing an exposure result obtained by exposing by a conventional method in Example 1.

FIG. 14 is a schematic diagram showing a method of measuring an image shape in the first embodiment.

FIG. 15 is a schematic diagram showing a position where a photodiode is stopped in order to measure an image shape in the first embodiment.

FIG. 16 is a diagram illustrating a result of exposure performed by an exposure method that performs distortion correction in the first embodiment.

FIG. 17 is a flowchart showing an exposure method in which distortion correction and light amount correction are simultaneously performed in the first embodiment.

FIG. 18 is a diagram illustrating a result of exposure performed by an exposure method in which distortion correction and light amount correction are simultaneously performed in the first embodiment.

FIG. 19 is a diagram of a two-dimensional code input in Embodiment 2.

FIG. 20 is a view showing an exposure result obtained by exposing by a conventional method in Example 2.

FIG. 21 is a diagram illustrating a result of exposure performed by an exposure method in which light amount correction is performed in Example 2.

FIG. 22 is a flowchart showing an exposure method in which distortion correction and light amount correction are simultaneously performed in the second embodiment.

FIG. 23 is a diagram showing a result of exposure performed by an exposure method in which distortion correction and light amount correction are simultaneously performed in Example 2.

FIG. 24 is a diagram showing the secular change of the light source light quantity;

FIG. 25 is a schematic diagram of an exposure apparatus when feedback is performed on the light source light amount in the second embodiment.

FIG. 26 is a diagram illustrating a change in the light source light amount when feedback is performed in the second embodiment.

FIG. 27 is a schematic view showing a conventional exposure apparatus.

[Explanation of symbols]

1: light source 2: DMD 3: light absorber 4: lens system 5: wafer 6: support table 7: XY stage 81: light detection means (photodiode) 82: light detection means (CCD) 9: control means 10: Recording means
11: Dummy optical system 12: Dummy lens system 13: Shutter 801: Support 71: Motor encoder signal 72: Motor encoder signal

Claims (13)

[Claims] 1. A light source means for supplying a substantially parallel light beam, and a plurality of micro mirrors capable of changing directions independently of each other, and the light beam from the light source means is provided by each of the plurality of micro mirrors. An exposure apparatus for forming an image on an object to be exposed by the light flux reflected and deflected by the spatial light modulator, and exposing the object to be exposed; An exposure apparatus, comprising: a light detecting means disposed in the light detecting means; and a control means for controlling an orientation of each of the micro mirrors of the spatial light modulating means based on an output of the light detecting means. 2. A light source means for supplying a substantially parallel light beam, and a plurality of micro mirrors capable of changing directions independently of each other, and each of the plurality of micro mirrors outputs light from the light source means. An exposure apparatus for forming an image on an object to be exposed by the light beam reflected and deflected by the spatial light modulation means, and exposing the object to be exposed; A dummy optical system provided in a traveling direction of a light beam reflected in a direction not contributing to exposure by the modulation unit; a light detection unit arranged in the dummy optical system; and the spatial light modulation based on an output of the light detection unit. Control means for controlling the direction of each of said micromirrors. 3. The control unit according to claim 1, wherein the control unit includes a recording unit that records measurement data obtained by the light detection unit and calculation data calculated by the control unit based on the measurement data. Exposure equipment. 4. An exposure apparatus according to claim 1, wherein an openable shutter is provided between said spatial light modulator and said object to be exposed. 5. The exposure apparatus according to claim 1, wherein the light source is a laser light source. 6. The exposure apparatus according to claim 1, wherein said light source means is a lamp light source. 7. The exposure apparatus according to claim 1, wherein a collimating lens is added to said light source means. 8. The exposure apparatus according to claim 1, wherein the spatial light modulator is a digital micromirror device (DMD). 9. A reduction optical unit or an enlargement optical unit is provided between the spatial light modulator and the object to be exposed.
The exposure apparatus according to any one of claims 1 to 8. 10. A substantially parallel light beam supplied by the light source means is reflected and deflected by each of the plurality of minute mirrors of the spatial light modulation means having a plurality of minute mirrors capable of changing directions independently of each other; In an exposure method for forming an image on an object to be exposed and exposing the object to be exposed to the shape of the image, distortion data of an image on the object to be exposed calculated or light provided near the object to be exposed is calculated. An exposure method, comprising: changing and controlling the tilting minute mirror in the spatial light modulator based on distortion data of an image on the object to be exposed obtained by measurement by a detector. 11. A substantially parallel light beam supplied by the light source means is reflected and deflected by each of the plurality of minute mirrors of the spatial light modulation means having a plurality of minute mirrors capable of changing directions independently of each other. An exposure method for forming an image on an object to be exposed and exposing the object to be exposed to the shape of the image, wherein a dummy optical system through which light not directed to the object to be exposed among reflected light from the spatial light modulating means passes. Exposure characterized by changing and controlling the micro mirror to be tilted in the spatial light modulating means based on distortion data of an image on the dummy optical system obtained and measured by the light detecting means provided above. Method. 12. A light beam supplied by the light source means is reflected and deflected by each of the plurality of minute mirrors of the spatial light modulating means having a plurality of minute mirrors capable of changing directions independently of each other. In an exposure method for forming an image on an object to be exposed and exposing the object to be exposed to the shape of the image, distortion data of an image on the object to be exposed calculated or light provided near the object to be exposed is calculated. Based on the light quantity distribution data of the image on the object to be exposed obtained by the measurement by the detecting means, each micro mirror in the spatial light modulating means
An exposure method characterized by repeatedly tilting by M control. 13. A substantially parallel light beam supplied by the light source means is reflected and deflected by each of the plurality of minute mirrors of the spatial light adjusting means having a plurality of minute mirrors capable of changing directions independently of each other. An exposure method for forming an image on an object to be exposed and exposing the object to be exposed to the shape of the image, wherein a light not reflected on the object to be exposed among light reflected from the spatial light modulator passes therethrough. The respective small mirrors in the spatial light modulator are repeatedly tilted by PWM control based on light amount data of an image on the dummy optical system obtained by measurement by a light detector provided on the system. Exposure method.