JP6723564B2 - Exposure method - Google Patents

Description

The present invention relates to an exposure method, and can be suitably used for an exposure method using a DMD (Digital Micromirror Device), for example.

For example, in Japanese Patent Laid-Open No. 2006-186364 (Patent Document 1), a data operation arranged so as to perform conversion by adding a point spread function matrix in a pseudo-inverse matrix format to a column vector representing a requested pattern. A lithographic apparatus comprising a device is described. The point spread function matrix contains information about the shape and relative position of the point spread function of each light spot exposed on the substrate by one of the sub-beams of radiation at a given time.

JP, 2006-186364, A

In the exposure method using the DMD, the exposure patterns are projected onto the substrate (the surface of the substrate, the upper surface of the substrate) by turning on or off the micro mirrors arranged in a grid pattern (switching the inclination of the micro mirrors). .. The light emitted from the light source to the DMD through the illumination optical system is reflected by the ON micromirror and is further projected onto the substrate to be exposed through the reduction projection optical system. However, there is a problem that the exposure amount on the substrate depends on the shape of the exposure pattern, and a resist pattern having a desired processed shape cannot be formed on the substrate, and as a result, the manufacturing yield of products is reduced.

Other problems and novel features will be apparent from the description of the present specification and the accompanying drawings.

An exposure method according to one embodiment includes (a) a step of preparing original image data, (b) an image processing filter applied to the original image data, and filter image data approximate to an exposure pattern projected on a surface of a substrate. A step of acquiring, (c) a step of dividing the original image data by the filter image data to obtain corrected image data, and a step of (d) applying an image processing filter to the corrected image data to form an exposure pattern projected on the surface of the substrate. The step of acquiring new filtered image data to be approximated is included. Further, the step (e) includes a step of determining whether or not the amount of light in a region exposed to light in the new filtered image data is constant. In step (e), when the amount of light in the area illuminated by light shows a desired value, the corrected image data is converted into gradation grayscale drawing data. When the amount of light in the area illuminated by light in step (e) does not indicate the desired value, the corrected image data is replaced with the original image data, the new filtered image data is replaced with the filtered image data, and (e) The steps (c), (d), and (e) are repeated until the amount of light in the area exposed to light in step) shows a desired value.

According to one embodiment, it is possible to suppress the bias of the exposure amount on the substrate depending on the shape of the exposure pattern and form a resist pattern having a desired processed shape on the substrate. As a result, the manufacturing yield of products can be improved.

1 is a schematic configuration diagram of an exposure apparatus according to an embodiment. FIG. 6 is a flowchart illustrating a method of creating corrected image data according to one embodiment. FIG. 6 is a light amount distribution chart of a point spread function of one pixel according to one embodiment. FIG. 6 is a light amount distribution chart showing a light amount of each divided portion by dividing a light diffusion region of one pixel into a plurality of portions according to one embodiment. FIG. 3 is a light amount distribution chart showing a light amount of each pixel by dividing a light diffusion region of one pixel into a plurality of regions according to one embodiment. (A) is a plan view showing original image data according to one embodiment, and (b) is a light amount distribution diagram showing a light amount along line AA′ in FIG. (A) is a plan view showing filtered image data obtained by applying an image processing filter to original image data according to one embodiment, and (b) is a light amount distribution showing a light amount along line AA′ in FIG. It is a figure. It is a figure explaining the correction calculation method of the image data by one embodiment. (A) is a plan view showing corrected image data according to one embodiment, and (b) is a light quantity distribution chart showing a light quantity along line AA′ in FIG. (A) is a plan view showing new filtered image data obtained by applying an image processing filter to the corrected image data according to one embodiment, and (b) shows the light quantity along the line AA' in (a). It is a light amount distribution map. (A) is a plan view showing corrected image data after repeating correction calculation of original image data four times according to one embodiment, and (b) shows a light amount along line AA′ in FIG. It is a light amount distribution chart shown. FIG. 7A is a plan view showing new filtered image data obtained by applying an image processing filter to the corrected image data after the correction calculation of the original image data according to one embodiment is repeated four times, and FIG. It is a light quantity distribution chart which shows the light quantity in the AA' line of (a). (A) is a plan view of a resist pattern formed on a substrate by exposure using original image data, (b) is an exposure using corrected image data after repeating correction calculation of original image data four times FIG. 6 is a plan view of a resist pattern formed on a substrate by.

Hereinafter, embodiments will be described in detail with reference to the drawings. In all the drawings for explaining the embodiments, members having the same function are designated by the same or related reference numerals, and repeated description thereof will be omitted. In addition, when there are a plurality of similar members (sites), a symbol may be added to the generic symbol to indicate an individual or specific site. In the following embodiments, the description of the same or similar parts will not be repeated in principle unless particularly necessary.

Further, in the drawings used in the embodiments, hatching may be omitted even in a sectional view in order to make the drawings easy to see. Further, even in a plan view, hatching may be added in order to make the drawing easy to see.

Further, in the sectional view and the plan view, the size of each part does not correspond to the actual device, and in order to make the drawing easy to understand, a specific part may be displayed relatively large. Even when the cross-sectional view and the plan view correspond to each other, a specific portion may be displayed relatively large in order to make the drawing easy to understand.

(task to solve)
In the exposure method using the DMD, the exposure pattern is projected on the substrate by turning on or off the micromirrors arranged in a grid pattern. The light emitted from the light source to the DVD through the illumination optical system is reflected by the ON micromirror, and is further projected through the reduction projection optical system onto the substrate to be exposed. In the reduction projection optical system, light reflected by, for example, a square micromirror having a side of 10.8 μm, which constitutes the DMD, is reduced to a square light spot having a side of 0.5 μm on the substrate.

However, when a rectangular light spot with a side of 0.5 μm is reduced and projected on the substrate through the reduction projection optical system, a square with a side of 0.5 μm is generated by a distribution called a point spread function (point spread function). Light spreads to the surrounding area. Therefore, when one micromirror is ON, the amount of light reflected by the one micromirror and incident on the substrate changes depending on whether the micromirrors around it are OFF or ON. ..

For example, when one micro mirror is ON and all the surrounding micro mirrors are OFF, the light reflected from the one micro mirror is projected onto the projection surface on the substrate, and the light is not incident from the surroundings. Don't come However, when one micro mirror is ON and some or all of the surrounding micro mirrors are ON, the projection surface on the substrate onto which the light reflected by the one micro mirror is projected is Light comes in and the amount of light increases.

That is, the exposure amount on the substrate is biased depending on the shape of the exposure pattern, and a resist pattern having a desired processed shape cannot be formed on the substrate. Specifically, an exposure pattern with a small number of pixels with micromirrors ON in the surroundings, for example, a thin exposure pattern or an exposure amount at the corners of the exposure pattern is insufficient, and an exposure pattern with many pixels with micromirrors in the surroundings, such as a thick one. The pattern has too much exposure. As a result, there is a problem that the manufacturing yield of the products is reduced.

(Embodiment)
《Exposure device》
An exposure apparatus according to this embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of an exposure apparatus according to this embodiment.

As shown in FIG. 1, the exposure apparatus 10 includes an exposure optical system 30 that projects an exposure pattern onto the surface of the substrate 20 during exposure, and an autofocus that detects a focus position (focus position) of the surface of the substrate 20. Optical system 40 for use. The optical system for projecting the focusing pattern on the surface of the substrate 20 of the autofocus optical system 40 has the same configuration as the exposure optical system 30.

The exposure optical system 30 projects an exposure pattern onto the surface of the substrate 20 placed on the stage 50. The exposure optical system 30 includes an exposure light source 31, a collimator lens 32, mirrors 33a, 33b and 33c, a DMD 34 that is a spatial light modulator, a relay lens 35, an objective lens 36, and the like.

Light for exposure (short wavelength light such as blue light or ultraviolet light) output from the exposure light source 31 enters the DMD 34 via the collimator lens 32 and the mirrors 33a and 33b, and the light reflected by the DMD 34 is reflected by the mirror 33c, The light enters the surface of the substrate 20 via the relay lens 35 and the objective lens 36. As described above, the exposure apparatus 10 according to the present embodiment is a maskless exposure apparatus.

The exposure light source 31 is composed of, for example, an LED (Light Emitting Diode) whose main wavelength is 405 nm.

The collimator lens 32 shapes the light output from the exposure light source 31 into parallel light, and the mirrors 33a and 33b make the light transmitted through the collimator lens 32 incident on the DMD 34.

The DMD 34 is a panel formed by laying fine micromirrors (also called “mirror elements”) on a semiconductor element in a grid pattern (lattice pattern), and each micromirror is independent. By changing the tilt angle, the projection of the light output from the exposure light source 31 can be turned on or off. A controller (not shown) is electrically connected to the DMD 34, and a micromirror at a predetermined position in the DMD 34 reflects light. As a result, the DMD 34 forms an exposure pattern of a desired shape projected on the surface of the substrate 20.

The mirror 33c causes the light reflected by the DMD 34 to enter the relay lens 35, and the relay lens 35 corrects the exposure pattern formed by the DMD 34 by magnification. For example, in the case of projecting an exposure pattern formed by the DMD 34, the micromirror of the DMD 34 is a quadrangle having a side of 10.8 μm, and when it is reduced and projected by the objective lens 36 to, for example, a size of 1/20, the substrate 20 On the surface of, the exposure pattern is a quadrangle having a side of 0.54 μm. However, by correcting the magnification with the relay lens 35, it is possible to reduce and project a square exposure pattern having a side of 0.5 μm on the surface of the substrate 20.

In the present embodiment, a quadrangle exposure pattern corresponding to one micro mirror and projected on the surface of the substrate 20 and having a side of 0.5 μm is defined as one pixel, but it goes without saying that the exposure pattern is not limited to this.

The objective lens 36 focuses the light transmitted through the relay lens 35 on the surface of the substrate 20.

The auto-focusing optical system 40 projects a focusing pattern onto the surface of the substrate 20 placed on the stage 50 and receives light reflected by the surface of the substrate 20. The auto-focusing optical system 40 includes a focusing light source 41, a collimator lens 42, a half mirror 43, mirrors 33a, 33b and 33c, a DMD 34, a relay lens 35, an objective lens 36, a half mirror 44, an imaging lens 45, and a CCD (Charge). Coupled Device) 46 and the like. Of these, the mirrors 33a, 33b, 33c, the DMD 34, the relay lens 35, and the objective lens 36 are commonly used in the exposure optical system 30 and the autofocus optical system 40.

The light (long-wavelength light such as infrared light) output from the focusing light source 41 enters the DMD 34 via the collimator lens 42, the half mirror 43, and the mirrors 33a and 33b, and the light reflected by the DMD 34 is reflected by the mirror 33c and the relay lens 35. And enters the surface of the substrate 20 through the objective lens 36. Further, the light reflected on the surface of the substrate 20 forms an image on the CCD 46 via the objective lens 36, the half mirror 44, and the imaging lens 45.

The focusing light source 41 is composed of, for example, a red light emitting diode.

The collimator lens 42 shapes the light output from the focusing light source 41 into parallel light, and the half mirror 43 makes the optical axis of the light transmitted through the collimator lens 42 coaxial with the optical axis of the exposure light source 31 and the mirrors 33a and 33b. Incident on.

The DMD 34 forming the focusing optical system 40 forms a focusing pattern, for example, a stripe pattern, of a desired shape projected on the surface of the substrate 20.

The objective lens 36 also serves as an image forming optical system that forms an image of the light reflected on the surface of the substrate 20 on the image forming surface of the CCD 46 as the light for focusing, and the light reflected on the surface of the substrate 20 is the objective lens again. It passes through 36 and enters the half mirror 44.

The light entering from the objective lens 36 is reflected by the half mirror 44 and enters the imaging lens 45. The CCD 46 is a photoelectric conversion element that receives the light that has passed through the imaging lens 45 and converts it into an electrical signal, and also functions as an imaging unit.

<Exposure method>
An exposure method according to this embodiment will be described with reference to FIG.

As shown in FIG. 1, first, the substrate 20 is placed on the stage 50.

Then, the substrate 20 is moved so that the exposure pattern is projected from the DMD 34 to a predetermined position on the surface of the substrate 20.

Next, an autofocus process is performed using the focusing optical system 40. First, when the focusing light (long-wavelength light) is output from the focusing light source 41, this output light is shaped into parallel light by the collimator lens 42 and is coaxial with the optical axis of the output light of the exposure light source 31 by the half mirror 43. Then, the light is reflected by the mirrors 33a and 33b and enters the DMD 34.

Subsequently, when the focusing pattern is reflected by the micro mirror of the DMD 34, the focusing pattern is reflected by the mirror 33c, the magnification is corrected by the relay lens 35, and the objective pattern is projected from the objective lens 36 onto the surface of the substrate 20.

Subsequently, when the focusing pattern is projected on the surface of the substrate 20, the reflected light of the substrate 20 again passes through the objective lens 36 and enters the half mirror 44. Then, the reflected light is made incident on the imaging lens 45 by the half mirror 44.

Subsequently, the light transmitted through the imaging lens 45 is received by the CCD 46, and the focus position of the substrate 20 is determined by analyzing the focusing pattern received by the CCD 46. After that, the substrate 20 is moved to the in-focus position according to an instruction signal from a control unit (not shown).

Next, an exposure process is performed using the exposure optical system 30. First, when the exposure light (short-wavelength light) is output from the exposure light source 31, the output light is shaped into parallel light by the collimator lens 32, transmitted through the half mirror 43, and then reflected by the mirrors 33a and 33b. It is incident on the DMD 34.

Then, when the exposure pattern is reflected by the micro mirror of the DMD 34, the exposure pattern is reflected by the mirror 33c, the magnification is corrected by the relay lens 35, and the exposure pattern is projected from the objective lens 36 onto the surface of the substrate 20. As a result, an exposure pattern having a desired shape is projected on the surface of the substrate 20. As described above, in the present embodiment, by repeating the autofocus process and the exposure process, a desired exposure pattern can be exposed on the resist applied to the surface of the substrate 20.

The exposure method according to the present embodiment is characterized in that the exposure amount on the substrate 20 is adjusted for each pixel in accordance with the shape of the exposure pattern in order to reduce the bias of the exposure amount on the substrate 20. That is, although the original image data is binary data that is ON or OFF for each pixel, the original image data is converted into corrected image data having an 8-bit luminance gradation, for example. Then, the brightness of each pixel is adjusted according to the shape of the exposure pattern. For example, a pixel having a small number of ON pixels in the periphery such as a thin exposure pattern is bright, and a pixel having a large number of ON pixels in the periphery such as a thick exposure pattern is dark. Then, by exposing according to the brightness of the corrected image data, the bias of the exposure amount on the substrate depending on the shape of the exposure pattern is suppressed.

Hereinafter, a method of creating corrected image data according to the present embodiment will be described in detail with reference to FIGS.

FIG. 2 is a flowchart illustrating a method of creating corrected image data. FIG. 3 is a light quantity distribution diagram of a point spread function of one pixel obtained from a theoretical formula. FIG. 4 is a light amount distribution chart showing a light amount of each divided portion by dividing the light diffusion region of one pixel into a plurality of portions. FIG. 5 is a light quantity distribution diagram showing a light quantity of one pixel divided into a plurality of areas and numerically representing the light quantity of each of the divided areas.

6A and 6B are a plan view and a light amount distribution diagram showing the original image data, respectively. 7A and 7B are respectively a plan view and a light amount distribution diagram showing filtered image data obtained by applying an image processing filter to original image data. FIG. 8 is a diagram illustrating a method of calculating correction of image data. 9A and 9B are a plan view and a light amount distribution diagram showing corrected image data, respectively. 10A and 10B are a plan view and a light amount distribution diagram showing new filtered image data obtained by applying the image processing filter to the corrected image data. 11A and 11B are a plan view and a light amount distribution diagram showing the corrected image data after the correction calculation of the original image data is repeated four times, respectively. 12A and 12B are a plan view and a light amount distribution diagram showing new filtered image data obtained by applying the image processing filter to the corrected image data after the correction calculation of the original image data is repeated four times, respectively. ..

<Step 1 (Process P1 shown in FIG. 2)>
As shown in FIG. 3, the light spread of one pixel is obtained from a theoretical formula.

FIG. 3 shows the light amount distribution of the point spread function when the light amount of one pixel made of a quadrangle having a side of 0.5 μm is 1. Specifically, in a region of 5 μm in the X direction and 5 μm in the Y direction orthogonal to the X direction (hereinafter, referred to as a light spread region), it is located at the center of the region and is composed of a quadrangle of 0.5 μm on each side. The light amount distribution of the point spread function when the light amount of the pixel is normalized as 1 (the maximum value is 1 and the minimum value is 0) is shown. In the present embodiment, one pixel corresponds to one micromirror forming the DMD.

<Step 2 (Process P2 shown in FIG. 2)>
As shown in FIGS. 4 and 5, the light diffusion area of one pixel is divided into a plurality of areas, and the light amount of each of the divided areas is obtained to create an image processing filter.

This image processing filter is applied to black-and-white image data (corresponding to original image data or corrected image data described later) (also referred to as "convolution calculation") to simulate the amount of light emitted to the work surface (surface of the substrate). can do.

For example, a light spread region consisting of a quadrangle with a side of 5 μm is divided into nine in the X direction and divided into nine in the Y direction, and a quadrangle with a side of 0.5 μm is formed. Set up. At the center of the light spreading area, one pixel having a square shape of 0.5 μm on a side and having a light amount of 1 is arranged. Then, the amount of light at each of the divisions is obtained, and an image processing filter is created from the distribution of the amount of light in the spread area of the light.

<Step 3 (Process P3 shown in FIG. 2)>
As shown in FIGS. 6A and 6B, the original image data OD is prepared.

In the present embodiment, the original image data OD of 0.5 μm line and space is used as an example. The original image data OD is represented by binary data in which the maximum value of the light amount is 1 and the minimum value of the light amount is 0.

<Step 4 (Process P4 shown in FIG. 2)>
As shown in FIGS. 7A and 7B, filtered image processing is performed on the original image data OD to obtain filtered image data FDn.

By applying the image processing filter to the original image data OD, it is possible to obtain the filtered image data FDn that approximates the image (exposure pattern) projected on the surface of the substrate.

However, in the filtered image data FDn obtained by performing the filtered image processing on the original image data OD, the amount of light in the area illuminated by the light is not constant. That is, in the exposure using the original image data OD, the amount of light is increased or decreased at the end of the line & space as compared with the central portion of the line & space, and the exposure amount on the surface of the substrate is the pattern of line & space. It can be seen that there is a bias depending on the shape or pattern position.

Therefore, the original image data OD is corrected so that the amount of light in a region of the filtered image data FDn that is exposed to light becomes constant. Specifically, as described in <Step 5> to <Step 10> below, the original image data OD is corrected, filtered image processing is performed on the corrected original image data OD, and the corrected original image data is corrected. Acquire new filtered image data of OD. Then, the correction of the original image data OD is repeated until the amount of light in the area that is exposed to light in the new filtered image data becomes constant.

<Step 5 (Process P5 shown in FIG. 2)>
As shown in FIGS. 8 and 9A and 9B, the original image data OD is divided by the filtered image data FDn to obtain corrected image data CD (=OD/FDn) obtained by correcting the original image data OD. ..

That is, the corrected image data CD is obtained by calculating the light amount of the pixel having the same position in the original image data OD and the position in the filtered image data FDn for all the pixels. The original image data OD is represented by binary data, but the corrected image data CD is represented by a plurality of bits of brightness gradation, for example, 16 bits of brightness gradation.

<Step 6 (Process P6 shown in FIG. 2)>
As shown in FIGS. 10A and 10B, filtered image processing is performed on the corrected image data CD obtained by correcting the original image data OD, and new filtered image data FD(n+1) is acquired.

By applying the image processing filter to the corrected image data CD, it is possible to acquire new filtered image data FD(n+1) that approximates the image (exposure pattern) projected on the surface of the substrate.

In the new filter image data FD(n+1) obtained by performing the filter image processing on the corrected image data CD, the amount of light in the area illuminated by the light is the same as the filter image data FDn shown in FIGS. 7A and 7B. Closer to a constant value than.

<Step 7 (Process P7 shown in FIG. 2)>
In the new filter image data FD(n+1) obtained by performing the filter image processing on the corrected image data CD, it is determined whether or not the light amount of the area illuminated by light satisfies or does not satisfy a desired constant value.

In the new filter image data FD(n+1), when the light amount of the area on which the light hits does not satisfy the desired constant value, the process proceeds from <Step 8> to <Step 9>, and the new filter image data FD(n+1) In the case where the amount of light in the area illuminated by light satisfies the desired constant value, the process proceeds to <Step 10>.

<Step 8 (Step 8 shown in FIG. 2)>
With the new filtered image data FD(n+1) shown in FIGS. 10(a) and 10(b), it is determined that the amount of light in the area exposed to light does not satisfy the desired constant value, and the corrected image data CD Is further corrected.

Therefore, the corrected image data CD is replaced with the original image data OD, and the new filtered image data FD(n+1) is replaced with the filtered image data FDn.

<Step 9 (Processes P5, P6, P7 shown in FIG. 2>
Using the corrected image data CD replaced with the original image data OD and the new filtered image data FD(n+1) replaced with the filtered image data FDn, the above <step 5>, the above <step 6> and the above <step Repeat 7>.

First, in the same manner as described in <Step 5> above, a new filter image in which the original image data OD (correction image data CD replaced with the original image data OD) is replaced with the filter image data FDn (filter image data FDn). The corrected image data CD (=OD/FDn) is obtained again by dividing by the data FD(n+1).

Subsequently, in the same manner as described in the above-mentioned <Step 6>, the filter image processing is performed on the corrected image data CD to obtain new filter image data FD(n+1).

Then, in the same manner as described in the above-mentioned <Step 7>, it is determined whether or not the light amount of the area to which the light is applied satisfies the desired constant value in the new filter image data FD(n+1).

Then, in the new filtered image data FD(n+1), when the light amount of the area illuminated by the light does not satisfy the desired constant value, the corrected image data CD is further corrected. That is, in the same manner as described in <Step 8> above, the corrected image data CD is replaced with the original image data OD, the new filter image data FD(n+1) is replaced with the filter image data FDn, and the above-mentioned <Step 5>, <Step 6> described above, and <Step 7> described above are repeated.

In this way, the original image data OD is obtained until the amount of light in the area exposed to light in the new filtered image data FD(n+1) reaches a desired constant value, in other words, until the luminance of the pixels whose micromirrors are ON is sufficiently aligned. Repeat the correction calculation of. Then, by the filter image processing, the corrected image data CD that can obtain the new filter image data FD(n+1) in which the light amount of the area on which the light hits has a desired constant value is obtained.

In the new filtered image data FD(n+1), if the amount of light in the area illuminated by light satisfies the desired constant value, the process proceeds to <Step 10>.

In the present embodiment, new filtered image data FD5 (see FIG. 11) obtained by performing filtered image processing on the corrected image data CD4 (FIGS. 11A and 11B) in which the correction calculation of the original image data OD is repeated four times. 12(a) and 12(b), the amount of light in the region where the light hits could satisfy the desired constant value.

<Step 10 (Process P9 shown in FIG. 2)>
In the new filtered image data FD(n+1), when the amount of light in the area illuminated by light satisfies a desired constant value, the corrected image data CD is converted into the desired grayscale drawing data. Then, using this drawing data, a desired exposure pattern is projected on the surface of the substrate.

In the present embodiment, as shown in FIGS. 12(a) and 12(b), the amount of light in the area where the new filter image data FD5 is exposed to light has a substantially constant value. That is, since the light amount becomes almost constant at the end and center of the line & space, the exposure of the surface of the substrate is performed in the exposure using the corrected image data CD4 shown in FIGS. 11A and 11B. Since the amount does not depend on the line & space pattern shape or pattern arrangement, it is possible to form a line & space resist pattern having a desired processing shape on the surface of the substrate.

In the present embodiment, the correction calculation of the original image data OD is repeated four times to obtain the corrected image data CD4 in which the exposure amount on the surface of the substrate 20 does not depend on the shape of the exposure pattern. It goes without saying that the number of corrections of is not limited to this.

FIG. 13A is a plan view of the resist pattern formed on the substrate by exposure using the original image data, and FIG. 13B is a plan view of the original image data correction calculation according to the present embodiment. It is a top view of a resist pattern formed on a substrate by exposure using the corrected image data after repeating.

In the exposure using the original image data shown in FIG. 13A, the lines located outside the repeating pattern of lines and spaces are thin and short. On the other hand, in the exposure using the corrected image data according to the present embodiment shown in FIG. 13B, the thickness and length of the line located outside the repeating pattern of lines and spaces are different from those in other regions. The thickness and length of the positioned line are approximately the same, and a desired line & space repeating pattern is formed.

As described above, according to the present embodiment, by correcting the original image data by performing the filter image processing a plurality of times, it is possible to create the corrected image data in which the bias of the exposure amount is reduced. As a result, it is possible to suppress the bias of the exposure amount on the substrate depending on the shape of the exposure pattern and form a resist pattern having a desired processed shape on the substrate. As a result, the manufacturing yield of products can be improved.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

10 exposure device 20 substrate 30 exposure optical system 31 exposure light source 32 collimator lenses 33a, 33b, 33c mirror 34 DMD
35 Relay Lens 36 Objective Lens 40 Auto Focus Optical System 41 Focusing Light Source 42 Collimator Lens 43 Half Mirror 44 Half Mirror 45 Imaging Lens 46 CCD
50 stages

Claims (3)

An exposure method for projecting an exposure pattern on a surface of a substrate by turning on or off a plurality of micromirrors arranged in a grid pattern that form a DMD,
(A) a step of preparing original image data,
(B) applying an image processing filter to the original image data to obtain filtered image data that approximates an exposure pattern projected on the surface of the substrate,
(C) dividing the original image data by the filtered image data to correct the original image data to obtain corrected image data,
(D) applying the image processing filter to the corrected image data to obtain new filtered image data that approximates an exposure pattern projected on the surface of the substrate,
(E) a step of determining whether or not the amount of light in a region exposed to light in the new filtered image data is constant,
Including
The image processing filter is a light amount obtained by obtaining the spread of light of one pixel from a theoretical formula, dividing the spread region of light of the one pixel into a plurality, and obtaining each of the divided portions,
In the step (e), when the amount of light in the area illuminated by the light shows a constant value , the corrected image data is converted into gradation grayscale drawing data, and the surface of the substrate is exposed using the drawing data. Project the pattern,
In the step (e), when the amount of light in the area illuminated by the light does not show a constant value , the corrected image data is replaced with the original image data, and the new filtered image data is replaced with the filtered image data. An exposure method in which the steps (c), (d) and (e) are repeated. The exposure method according to claim 1 Symbol placement,
The one pixel is a quadrangle with 0.5 μm on each side,
The light spreading area is formed by a quadrangle having a side of 5 μm,
The one pixel is located at the center of the light spread area, and the light quantity of the light spread area is normalized by setting the light quantity of the one pixel to 1, thereby obtaining the image processing filter of the light spread area. , Exposure method. The exposure method according to claim 1 Symbol placement,
An exposure method in which one pixel corresponds to one micromirror.