JP2003057834A - Multiple exposure lithography system and multiple exposure lithography method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form circuit patterns taking the distortion of an optical system into consideration with high accuracy. SOLUTION: The prescribed patterns are formed on a forming surface by multiple exposure using an exposure unit having a multiplicity of micromirrors arrayed in a matrix form and an optical system for projecting the optical images from these micromirrors. The exposure point coordinate data indicating the relative positions of the micromirrors in the respective exposure units and the exposure position data indicating the relative positions of the respective exposure units to the drawing surface are added to form read-out address data. The exposure point coordinate data is measured values taking the distortion of the optical system into consideration. The raster data corresponding to the read-out address data is read out of a bit map memory 52 and is stored into an exposure data memory 54. The stored exposure data is applied to the individual micromirrors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing apparatus and a drawing method for drawing a predetermined pattern on a drawing surface using an exposure unit having a large number of modulators arranged in a matrix.

[0002]

2. Description of the Related Art A drawing apparatus as described above is generally used for optically drawing a fine pattern or a symbol such as a character on the surface of an appropriate object to be drawn. A typical example of use is drawing a circuit pattern when a printed circuit board is manufactured by a photolithography method. In this case, the object to be drawn is a photosensitive film for a photomask or a substrate. It is a photoresist layer.

In recent years, a series of processes from the circuit pattern design process to the drawing process have been integrated into a system, and the drawing apparatus plays a role in such an integrated system. In addition to the drawing device, the integrated system
CAD (Computer Aided) for designing circuit patterns
Design) station, CAM that edits vector data of circuit patterns obtained at this CAD station
(Computer Aided Manufacturing) Station etc. are provided. The vector data created by the CAD station or the vector data edited by the CAM station is transferred to the drawing device, where it is converted into raster data and then stored in the bitmap memory.

As one type of exposure unit, for example, D
MD (Digital Micromirror Device) or LCD (Li
quid Crystal Display) An array or the like is known. As is well known, micromirrors are arranged in a matrix on the reflecting surface of the DMD, and the reflecting directions of the individual micromirrors are independently controlled. Therefore, the entire reflecting surface of the DMD is covered. The introduced luminous flux is split as a luminous flux reflected by each micromirror, and therefore each micromirror functions as a modulation element. In the LCD array,
Liquid crystal is sealed between a pair of transparent substrates, and a large number of pairs of fine transparent electrodes aligned with each other are arranged in a matrix on both transparent substrates, and whether or not a voltage is applied to each pair of transparent electrodes. Thus, the transmission and non-transmission of the light flux is controlled, so that each pair of transparent electrodes functions as a modulation element.

The drawing apparatus is provided with an appropriate light source according to the photosensitivity of the object to be drawn, such as an ultra-high pressure mercury lamp, a xenon lamp, a flash lamp, an LED (Light Emitting Diode), a laser, and the exposure unit. Image optics are incorporated. The light flux emitted from the light source is introduced into the exposure unit through the illumination optical system, and the individual modulation elements of the exposure unit modulate the light flux incident thereon according to the raster data of the circuit pattern, whereby the circuit pattern is formed on the object to be drawn. It is exposed and optically drawn. in this case,
The size of the pixel of the drawn circuit pattern corresponds to the size of the modulation element. For example, when the magnification of the imaging optical system described above is equal, the size of the pixel of the drawing circuit pattern and the size of the modulation element are Are substantially equal.

Normally, the drawing area of the circuit pattern to be drawn on the drawing object is much larger than the exposure area by the exposure unit. Therefore, in order to draw the entire circuit pattern on the drawing object, the drawing object is drawn. It is necessary to scan the body with the exposure unit. That is, it is necessary to partially draw the circuit pattern while moving the exposure unit relative to the object to be drawn to obtain the entire circuit pattern. Therefore, conventionally, the drawing apparatus is provided with, for example, a drawing table movable along a predetermined scanning direction, and the exposure unit is arranged at a fixed position above the moving path of the drawing table. The object to be drawn is positioned at a predetermined position on the drawing table, and the circuit pattern is partially sequentially drawn and added while intermittently moving the drawing table along the scanning direction, so that the entire circuit pattern is Will be obtained. Such an exposure method is called a step & repeat method.

As another type of exposure unit,
For example, a laser beam scanning optical system is also known. In a drawing apparatus using an exposure unit of this type, a laser beam is deflected in a direction transverse to the moving direction of the drawing object, the drawing object is scanned by the laser beam, and the scanning laser beam is scanned. A desired circuit pattern is drawn by sequentially modulating the line drawing data (raster data).

[0008]

In any type of the conventional drawing apparatus as described above, the drawing resolution of the circuit pattern is determined by the pixel size (dot size) predetermined by each drawing apparatus. ). That is,
In a drawing apparatus having an exposure unit composed of modulation elements arranged in a matrix, the drawing resolution of the circuit pattern is determined by the size of each modulation element, that is, the pixel size, and in a drawing apparatus having a laser beam scanning optical system. Depends on the beam diameter of the scanning laser beam, that is, the pixel size.

Thus, conventionally, it is necessary that the pixel size when designing the circuit pattern in the CAD station or the CAM station is matched with the pixel size predetermined by the individual drawing device to draw the circuit pattern. . In other words, in order to increase the degree of freedom in designing the circuit pattern in the CAD station or the CAM station, it is necessary to prepare a drawing device that can cope with various pixel sizes, and a drawing device that can deal with various pixel sizes. If not prepared, the degree of freedom in designing the circuit pattern in the CAD station or CAM station will be limited.

In reality, the lenses used in the illumination optical system and the imaging optical system of the exposure unit have a unique distortion characteristic called distortion, and the projected image on the drawing surface has a designed circuit pattern. The problem is that they do not match exactly. In the past, various corrections were required, such as using a lens without distortion, or using only a modulation element corresponding to a portion of the projected image with less distortion for exposure. However, in the former case, a lens having no distortion is extremely expensive, and assembling of such a lens requires highly accurate mounting work, which requires a great deal of time and labor. Further, as the latter drawback, not only is the control system complicated, but the number of modulators that can actually be used is reduced, and as a result a sufficient exposure area cannot be secured.

Therefore, an object of the present invention is a drawing apparatus and a drawing method for drawing a predetermined pattern on a drawing surface by using an exposure unit having a large number of modulation elements arranged in a matrix. Regardless of the size of the pixel and the use of an optical system with distortion, it is possible to properly draw a predetermined pattern based on the pattern data. A novel multiple-exposure drawing apparatus and a multiple-exposure drawing method are provided.

[0012]

A multiple exposure drawing apparatus according to the present invention comprises a large number of modulation elements arranged in a matrix and an optical system for projecting an optical image formed by each modulation element onto a drawing surface. And an exposure unit having a predetermined pattern, memory means for holding raster data of a predetermined pattern, calculation means for calculating coordinate data indicating relative positions of optical images by individual modulators on a drawing surface, and raster data corresponding to the coordinate data. The exposure unit is provided with an exposure data generation unit that reads out and generates exposure data to be given to each modulation element of the exposure unit, and a modulation element control unit that drives and controls each modulation element based on the exposure data. The greatest feature is that a predetermined pattern is drawn on the drawing surface by exposure.

In the multiple exposure drawing apparatus, the coordinate data is specifically the sum of exposure point coordinate data indicating the relative position of each modulator in the exposure unit and exposure position data indicating the relative position of the exposure unit with respect to the drawing surface. Is.
Further, the exposure point coordinate data is an actual measurement value indicating the relative position of the optical image by each modulator when the origin is set on the optical image projected on the drawing surface by each exposure unit, and the exposure position data is , The relative movement amount from the initial exposure position when the drawing surface moves relative to the exposure unit.

The multiple exposure drawing method according to the present invention is
A multiple-exposure drawing method for drawing a predetermined pattern on a drawing surface by multiple exposure using at least one exposure unit having a large number of modulators arranged in a matrix, and holding raster data of the predetermined pattern in a memory means. And a second step of calculating coordinate data indicating the relative position of the optical image by the individual modulation elements on the drawing surface, and the raster data corresponding to the coordinate data is read out to the individual modulation elements of the exposure unit. It is characterized by comprising a third step of generating exposure data to be given and a fourth step of driving and controlling each modulation element based on the exposure data.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a multiple exposure drawing apparatus according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view schematically showing a first embodiment of a multiple exposure drawing apparatus according to the present invention. This multiple-exposure drawing apparatus is configured to directly draw a circuit pattern on a photoresist layer formed on a substrate for manufacturing a printed circuit board.

As shown in FIG. 1, the multiple exposure drawing apparatus 10 is shown.
Has a base 12 that is installed on the floor. Base 12
A pair of guide rails 14 are laid in parallel on the top, and a drawing table 16 is mounted on the guide rails 14. The drawing table 16 is driven by a suitable driving mechanism (not shown), such as a ball screw, by a motor such as a stepping motor, so that the drawing table 16 is relatively moved along the pair of guide rails 14 in the longitudinal direction, that is, the X direction. A substrate having a photoresist layer is placed on the drawing table 16 as the drawing target 30, and at this time, the drawing target 30 is appropriately fixed on the drawing table 16 by an appropriate clamp means (not shown).

A pair of guide rails 14 are mounted on the base 12.
The gate-like structure 18 is fixedly installed so as to straddle the gate.
A plurality of exposure units are provided on the upper surface of the structure 18 for drawing.
In the Y direction, which is perpendicular to the movement direction (X direction) of the bull 16.
It is arranged in two columns. Eight exposure units arranged in the first row
20 in order from the left side of the figure₀₁, 20₀₃, 20₀₅,
20₀₇, 20₀₉, 20₁₁, 20₁₃And 20₁₅Indicated by
Illustration of 7 exposure units in the 2nd row arranged behind
20 from the left side of₀₂, 20₀₄, 20₀₆, 20 ₀₈, 20
_Ten, 20₁₂And 20₁₄It shows with.

First row exposure unit 20₀₁, 20₀₃,
20₀₅, 20₀₇, 20₀₉, 20₁₁, 20₁₃And 20₁₅
And the exposure unit 20 in the second row₀₂, 20₀₄, 20₀₆,
20 ₀₈, 20_Ten, 20₁₂And 20₁₄Is so-called staggered
Will be placed. That is, the distance between two adjacent exposure units
The separation is set to be approximately equal to the width of one exposure unit.
Exposure unit 20 in the second row₀₂, 20₀₄, 20₀₆,
20₀₈, 20_Ten, 20₁₂And 20₁₄The array pitch of
First row exposure unit 20₀₁, 20₀₃, 20₀₅Two
0₀₇, 20₀₉, 20₁₁, 20₁₃And 20₁₅Array of
It is shifted by half a pitch with respect to Ji.

In this embodiment, 15 exposure units 2
Each of _{01 01 to} 20 ₁₅ is configured as a DMD unit, and the reflection surface of each exposure unit is, for example, 1024 × 1.
It is composed of 1310720 micromirrors arranged in a matrix of 280. Each exposure unit 20 ₀₁
˜20 ₁₅ are installed so that 1024 micromirrors along the X direction and 1280 micromirrors along the Y direction are arranged in a matrix.

An appropriate place on the upper surface of the gate structure 18,
For example, the light source device 22 is provided on the left side of the first exposure unit _{20001 in} the drawing. The light source device 22 includes a plurality of LEDs (Light Emitting Diodes) (not shown), and the light emitted from these LEDs is condensed and emitted from the emission port of the light source device 22 as a parallel light flux. The light source device 22 has LE
In addition to D, a laser, an ultra-high pressure mercury lamp, a xenon lamp, a flash lamp or the like may be used.

[0022] The exit of the light source device 22 is connected an optical fiber bundle of cables 15 present, each optical fiber cable 24 is extended to each of the fifteen exposure units 20 ₀₁ to 20 _15, thereby the illumination light is introduced from the light source device 22 to the respective exposure units 20 ₀₁ to 20 _15. Each of the exposure units 200 _{1 to} 20 ₁₅ modulates the illumination light from the light source device 22 according to the circuit pattern to be drawn, and advances on the drawing table 16 below the drawing, that is, inside the gate-shaped structure 18 on the drawing table 30. It emits toward. As a result, only the portion of the photoresist layer formed on the upper surface of the object 30 to be exposed is illuminated with the illumination light. The intensity of the illumination light is adjusted according to the sensitivity of the photoresist layer of the object 30 to be drawn.

[0023] Figure 2, main components of the first exposure unit 20 ₀₁ is conceptually illustrated. Other fourteen exposure units 20 ₀₂ to 20 ₁₅ have the same structure and function as the first exposure unit 20 _01, and a description thereof will be omitted.
An illumination optical system 26 and an imaging optical system 28 are incorporated in the first exposure unit ₂₀₀₀₁ , and DM is provided on the optical path between them.
The D element 27 is provided. The DMD element 27 is a device for operating a square micromirror having a side length C with high reflectance, which is formed by aluminum sputtering on a wafer, by an electrostatic field action. The micromirror is mounted on a silicon memory chip. To 1024 x 1280
1310720 are laid out in a matrix form. Each micro mirror can be rotated and tilted about a diagonal line and can be positioned in two stable postures.

The illumination optical system 26 includes a convex lens 26A and a collimating lens 26B, and the convex lens 26A is the light source 2.
It is optically coupled to the optical fiber cable 24 extended from 2. With such an illumination optical system 26, the light flux emitted from the optical fiber cable 24 is emitted from the first exposure unit 2
The entire reflective surface of 0 ₀₁ of the DMD element 27 is shaped into a parallel light beam LB such as lighting. The imaging optical system 28 includes two convex lenses 28A and 28C and a reflector 28B arranged between the two convex lenses 28A and 28C,
The magnification of the imaging optical system 28 is set to, for example, 1 × (magnification 1).

[0025] Individual micromirrors included in the first exposure unit 20 ₀₁ first reflecting position for reflecting the light beam incident on each imaging optical system 28 (hereinafter referred to as a exposure position) and the light beam Is operated so as to be rotationally displaced between a second reflection position (hereinafter, referred to as a non-exposure position) that reflects the light so as to deviate from the imaging optical system 28.
Any micromirror M (m, n) (1 ≦ m ≦ 102
4, 1 ≦ n ≦ 1280) is positioned at the exposure position, the spot light incident thereon is reflected toward the imaging optical system 28 as indicated by the alternate long and short dash line LB ₁ , and the micromirror M (m , N) are positioned in the non-exposure position, the spot light is reflected toward the light absorbing plate 29 and diverted from the image forming optical system 28 as shown by the chain line LB ₂ .

The spot light LB ₁ reflected from the micro mirror M (m, n) is guided by the imaging optical system 28 onto the drawing surface 32 of the object 30 to be drawn placed on the drawing table 16. For example, the size of each micro mirror M (m, n) included in the first exposure unit ₂₀₀₀₁ is C × C.
Then, since the magnification of the imaging optical system 28 is equal, the reflecting surface of the micromirror M (m, n) is the drawing surface 32.
An image is formed as the upper C × C exposure area U (m, n).
C is, for example, 20 μm.

One micro mirror M (m, n)
The C × C exposure area obtained by the above is referred to as a unit exposure area U (m, n) in the following description, and is obtained by all the micromirrors M (1,1) to M (1024,1280) (C ×). The exposure area of (1024) × (C × 1280) is referred to as the overall exposure area Ua ₀₁ .

In the upper left corner of FIG. 2, the micromirror M (1,
The unit exposure area U (1,1) corresponding to 1) is located in the lower left corner of the entire surface exposure area Ua ₀₁ , and the micromirror M in the lower left corner.
A unit exposure area U (102
4, 1) is located in the upper left corner of the entire exposure area Ua ₀₁ . Further, the unit exposure area U (1,1280) corresponding to the micro mirror M (1,1280) in the upper right corner is the entire surface exposure area U.
It is located in the lower right corner of a _{01, and} the micromirror M (1
024, 1280) corresponding to the unit exposure area U (102
4, 1280) is located in the upper right corner of the entire exposure area Ua ₀₁ .

In the first exposure unit ₂₀₀₀₁ , the individual micromirrors M (m, n) are normally positioned at the non-exposure position, but they are rotationally displaced from the non-exposure position to the exposure position during exposure. The control of the rotational displacement of the micro mirror M (m, n) from the non-exposure position to the exposure position is performed based on the raster data of the circuit pattern, as described later. The spot light LB ₂ diverted from the image forming optical system 28 is prevented from reaching the drawing surface 32 by the light absorbing plate 29.
Absorbed by

[0030] 131 contained in the first exposure unit 20 ₀₁
When all 0720 micromirrors are placed at the exposure position, all the spot lights reflected from all the micromirrors are made incident on the imaging optical system 28, and the first exposure unit 20 ₀₁ is placed on the drawing surface 32. Thus, the entire surface exposure area Ua ₀₁ is obtained. Regarding the size of the entire surface exposure area Ua ₀₁ , if the length C of one side of the unit exposure area U (m, n) is 20 μm, it is 25.6 mm (= 1024 × 20 μm) × 20.4.
It becomes 8 mm (= 1280 × 20 μm), and the total number of pixels included therein is of course 1024 × 1280.

A drawing process in the multiple exposure drawing apparatus will be described with reference to FIGS. Figure 3
(A)-(c) is a figure which shows a change with time of drawing processing in steps, and is a top view of drawing surface 32 of to-be-drawn object 30. For the sake of convenience of the following description, X-Y is on the plane including the drawing surface 32.
A Cartesian coordinate system is defined. Rectangular area surrounded by a broken line 15 of the exposure unit 20 _{01-20 15} entire exposure area Ua ₀₁ obtained on the X-Y plane by each ~U
a ₁₅ . 1st row whole surface exposure area Ua ₀₁ , Ua ₀₃ , U
a ₀₅ , Ua ₀₇ , Ua ₀₉ , Ua ₁₁ , Ua ₁₃ and Ua ₁₅ are arranged so that the lower side in the figure coincides with the Y axis, and the entire surface exposure regions Ua ₀₂ , Ua ₀₄ , Ua ₀₆ , Ua ₀₈ ,
Ua ₁₀ , Ua ₁₂ and Ua ₁₄ are arranged so that the lower side in the figure coincides with a straight line separated from the Y axis by a distance S on the negative side.

The X-axis of the XY orthogonal coordinate system is the exposure unit 2
It is perpendicular to the arrangement direction of _{01 01 to} 20 ₁₅ and therefore 13107 in each exposure unit 20 _{01 to} 20 ₁₅ respectively.
20 (1024 x 1280) micromirrors are also X-
They are arranged in a matrix along the X and Y axes of the Y orthogonal coordinate system.

In FIG. 3, the coordinate origin of the XY Cartesian coordinate system is
First exposure unit 20 in the first row₀₁All obtained by
Surface exposure area Ua₀₁Figure as it matches the lower left corner in the figure
Although shown, to be exact, the coordinate origin is the first exposure unit.
20₀₁The first line of the micromirror along the Y axis of the
Obtained by the first micromirror M (1,1)
Is located at the center of the unit exposure area U (1,1). Above
As described above, in the present embodiment, the unit exposure area U (1,1)
The size is 20μm × 20μm, so the Y-axis is the first dew
Overall exposure area Ua by the optical unit 20₀₁From the boundary of
Only 0 μm has entered the inside. In other words
For example, the eight exposure units 20 in the first row ₀₁, 20₀₃Two
0₀₅, 20₀₇, 20₀₉, 20₁₁, 20₁₃And 20₁₅of
1280 micros included in each first line
All centers of mirror M (1, n) (1 ≦ n ≦ 1280)
Is on the Y-axis.

Since the drawing surface 32 is moved in the negative direction along the X axis by the drawing table 16 as indicated by the white arrow, the entire surface exposure areas Ua _{01 to} Ua ₁₅ are relative to the drawing surface 32. It will move relative to the positive direction of the X axis.

Drawing start position SL set on the drawing surface 32
Is the Y axis, that is, the eight exposure units 20 in the first row₀₁Two
0₀₃, 20₀₅, 20₀₇, 20₀₉, 20₁₁, 20₁₃and
20 ₁₅The entire surface exposure area Ua of the first column corresponding to₀₁, Ua
₀₃, Ua₀₅, Ua₀₇, Ua₀₉, Ua₁₁, Ua₁₃And U
a₁₅If it coincides with the boundary of, the exposure unit of the first row
20₀₁, 20₀₃, 20₀₅, 20₀₇, 20₀₉, 20₁₁Two
0₁₃And 20₁₅The exposure of the drawing surface 32 is started by
It As shown in FIG. 3A, the entire surface exposure area in the first column
Ua₀₁, Ua₀₃, Ua₀₅, Ua₀₇, Ua₀₉, Ua₁₁, U
a₁₃And Ua₁₅Corresponding to the part that has not reached the Y-axis
The micro mirror was positioned in the non-exposure position
No exposure is performed as it is, and the entire surface exposure area Ua in the second row is
₀₂, Ua₀₄, Ua₀₆, Ua₀₈, Ua_Ten, Ua₁₂And U
a₁₄Also does not reach the Y-axis, the exposure unit 20₀₂,
20₀₄, 20₀₆, 20₀₈, 20_Ten, 20₁₂And 20₁₄
The exposure by is also stopped. In FIG. 3, the first column
8 exposure units 20₀₁, 20₀₃, 20₀₅Two
0₀₇, 20₀₉, 20₁₁, 20₁₃And 20₁₅By dew
The illuminated area is indicated by hatching that rises to the right.

When the drawing surface 32 is further moved and the boundaries of the entire surface exposure areas Ua ₀₂ , Ua ₀₄ , Ua ₀₆ , Ua ₀₈ , Ua ₁₀ , Ua ₁₂ and Ua ₁₄ coincide with the Y axis, seven pixels in the second row are aligned. Exposure units 20 ₀₂ , 20 ₀₄ , 20 ₀₆ , 20 ₀₈ , 2
The exposure with 0 ₁₀ , 20 ₁₂ and 20 ₁₄ is started. Figure 3 (b), the second column of the exposure unit 20 _02,
20 ₀₄ , 20 ₀₆ , 20 ₀₈ , 20 ₁₀ , 20 ₁₂ and 20 ₁₄
The exposure by means of the exposure unit ₂₀₀₀₁ , 2
0 _03, 20 _05, 20 _07, 20 _09, 20 _11, 20 ₁₃ and proceeds with a delay always a distance S than the exposure by 20 _15. In FIG. 3, the exposure units 20 ₀₂ , 2
The areas exposed by 0 ₀₄ , 20 ₀₆ , 20 ₀₈ , 20 ₁₀ , 20 ₁₂ and 20 ₁₄ are indicated by hatching to the lower right.

Further, the drawing surface 32 moves relatively, and FIG.
As shown in (c), the entire surface exposure area Ua of the first column₀₁, U
a₀₃, Ua₀₅, Ua₀₇, Ua₀₉, Ua₁₁, Ua₁₃and
Ua₁₅When the border of reaches the drawing end position EL, the first column
Exposure unit 20₀₁, 20₀₃, 20₀₅, 20₀₇, 20
₀₉, 20₁₁, 20₁₃And 20₁₅Stop the exposure by
To be Strictly speaking, the unit that reaches the drawing end position EL
Micromirror M corresponding to exposure area U (m, n)
It is stopped at the non-exposure position in order from (m, n). Figure 3
The drawing surface 32 further advances by the distance S from the state of (c).
And the entire surface exposure area Ua in the second column₀₂, Ua₀₄, Ua₀₆,
Ua₀₈, Ua_Ten, Ua₁₂And Ua₁₄Ends the drawing
Reaching the position EL, the exposure unit 20 in the second row₀₂, 20
₀₄, 20₀₆, 20 ₀₈, 20_Ten, 20₁₂And 20₁₄By
Exposure is stopped.

As described above, 15 exposure units 20
_{01-20 15} each exposing a band-shaped area in the X-axis, the width of the strip-like regions each entire exposure area Ua ₀₁ ~
Substantially matches the width of Ua ₁₅ . The boundary portion between two adjacent strip-shaped regions is overlapped by a small amount. In addition,
In order to match the circuit patterns to be drawn on the same line, the exposure units 20 ₀₁ , _{200 3} , 20 in the first column
_05, 20 _07, 20 _09, 20 _11, 20 when ₁₃ and 20 exposure data corresponding to the circuit pattern of the predetermined line ₁₅ is provided, the second column of the exposure unit 20 _02, 20 _04, 2
The exposure data of the same line is given to 0 ₀₆ , 20 ₀₈ , 20 ₁₀ , 20 ₁₂ and 20 ₁₄ at a timing delayed by the time when the drawing surface 32 moves the distance S.

As the exposure method, the operation of intermittently moving the drawing table 16 along the scanning direction and the operation of partially drawing the circuit pattern when the drawing table 16 is stopped are alternately repeated, A step-and-repeat (Step & Repeat) method may be adopted in which drawing areas are added to obtain the entire circuit pattern, or a method of simultaneously performing drawing operations while moving the drawing table 16 at a constant speed. Good. In the present embodiment, a step-and-repeat method is adopted to facilitate the description. That is, the multiple-exposure drawing apparatus 10 employs a drawing method of drawing the circuit pattern by multiple exposure according to the raster data of the circuit pattern while intermittently moving the drawing table 16 at a predetermined movement interval. The principle of such a multiple-exposure drawing method will be described below.

[0040] Figure 4 is a part of the entire exposure area Ua ₀₁ projected onto the drawing surface 32 by the first exposure unit 20 ₀₁ is shown, the entire exposure area Ua ₀₁ each micromirror M (m, n ) From the unit exposure area U (m, n). Here, the parameter m is the first exposure unit 20.
Shows the line numbers along the X-axis direction of _01, the parameter n is a line number along the Y-axis direction of the first exposure unit 20 _01, in the present embodiment 1 ≦ m ≦ 1024 and 1 ≦ n ≦ 1
It becomes 280.

In short, the unit exposure areas U (1,1), U
(1,2), U (1,3), U (1,4), U (1,
5), ..., U (1,1280) is the first exposure unit 20.
_The unit exposure areas U (2,1) and U (2,2) are obtained from 1280 micromirrors M (1,1) to M (1,1280) of the first line along the Y axis of _01. ), U
(2,3), U (2,4), U (2,5), ..., U
(2,1280) is 1280 micro mirrors M (2 of the second line along the Y-axis of the first exposure unit 20 _01,
1) to M (2,1280), and unit exposure areas U (3,1), U (3,2), U (3,2).
3), U (3,4), U (3,5), ..., U (3,12)
80) micromirror M of the third line along the Y-axis of the first exposure unit _{20 01 (3,1) ~M (3,1280} )
It is obtained from.

For example, the sum of the distance A (for example A = 4C) and the distance a (0 ≦ a <C) in which the moving distance per exposure is an integral multiple of the size C for one unit exposure area. To explain one case, the drawing table 16 is moved to the negative side along the X axis, that is, the first exposure unit 2
When _{01 01} moves relative to the drawing table 16 toward the positive side of the X-axis and the unit exposure area Ua ₀₁ reaches the drawing start position SL on the drawing surface 32, it is temporarily stopped there and the first exposure unit 20 of ₀₁ of the first line 1280 of the micro-mirror M (1,1) ~M (1,1280) is the first exposure to be operated in accordance with a raster data of a predetermined circuit pattern is carried out. The relative position of the drawing surface 32 at this time is defined as the first exposure position.

When the first exposure is completed, the first exposure unit ₂₀₀₀₁ again moves relative to the positive side along the X-axis, and the movement amount of the unit exposure area Ua ₀₁ becomes (A + a). , The first exposure unit ₂₀₀₀₁ is judged to have reached the second exposure position, and is stopped.
0 ₀₁ 1st to 5th lines of micromirror M (1, 1)
.About.M (5,1280) are operated according to the raster data of a predetermined circuit pattern to perform the second exposure.

When the second exposure is completed, the first exposure unit ₂₀₀₀₁ further moves along the X axis toward the positive side thereof (A
+ A) only be stopped at the third exposure position is moved, the first exposure unit 20 ₀₁ of the first to ninth lines micromirror M (1,1) ~M (9,1280) of a predetermined circuit pattern And the third exposure is performed.

As described above, every time the first exposure unit ₂₀₀₀₁ is moved to the positive side along the X axis by the movement amount (A + a), the exposure operation is repeated and the drawing surface 32 is stopped.
That is, the same area is subjected to multiple exposure by the first exposure unit ₂₀₀₀₁ multiple times. For example, a = 0, the first exposure unit 20 ₀₁ is moved to its positive side along the X-axis A (= 4C) by the unit exposure area U (m, n) center is always on the same point of Match. Therefore, the C × C area exposed by the leading micromirror M (1,1) in the first column is further exposed by the (4k + 1) th leading micromirror M (4k + 1,1) ( However, 1 ≦ k ≦ 255, a total of 256 times (= 1024C)
/ A) will be subjected to multiple exposure. On the other hand, when a ≠ 0, the centers of the overlapping unit exposure areas U (m, n) are gradually displaced by the distance a, and therefore the same area is not always subjected to multiple exposure 256 times. Therefore, the predetermined area is set to 25
In order to expose 6 times, 256 centers of each unit exposure area U (m, n) are evenly arranged in this predetermined area,
Substantially 256 times of multiple exposure is performed.

[0046] In Figure 3, the arrangement of the micromirrors of the exposure unit 20 _{01-20 15} but was parallel to the X-axis and Y-axis, fine angle posture of the exposure unit 20 _{01-20 15} with respect to the X axis α It may be configured to move while inclining only. At this time, every time the first exposure unit ₂₀₀₀₁ is moved to the positive side along the X axis by the movement amount (A + a), the unit exposure region U (m, n) is moved to the negative side along the Y axis. Will be relatively shifted by a predetermined distance.

[0047] Figure 5, the unit exposure region U when the exposure unit 20 ₀₁ is sequentially moved while inclined with respect to the X-axis
It is a figure which shows the displacement of (m, n) over time. Referring to FIG. 5, a part of the entire exposure area Ua ₀₁ with the first-time exposure position is shown in dashed lines, a portion of the entire exposure area Ua ₀₁ with the second exposure position is indicated by a dashed line, the A part of the entire surface exposure area Ua ₀₁ at the third exposure position is shown by a solid line, and a moving distance along the negative side of the Y axis of each unit exposure area U (m, n) is shown by b.

The first time the first exposure unit 20 ₀₁ of the first line micromirror M in the exposure position (1, 1) to
Unit exposure area U obtained by M (1,1280)
Focusing on (1,1), U (1,2), ... U (1,1280), these unit exposure regions U (1,1), U (1,2)
2), ... with respect to U (1,1280), units obtained by the first exposure unit 20 ₀₁ of the fifth line micromirrors M in the second exposure position (5,1) ~M (5,1280) Exposure areas U (5,1), U (5,2), ...
U (5,1280) are offset from each other by (+ a) and (-b) along the X-axis and Y-axis, respectively, and overlap each other,
Further, at the third exposure position, the first exposure unit 2
0 ₀₁ 9th line micromirrors M (9,1) to M
Unit exposure area U obtained by (9,1280)
(9,1), U (9,2), ... U (9,1280) are
They are shifted by (+ 2a) and (-2b) in the X-axis direction and the Y-axis direction, respectively, and overlap each other. In FIG. 5, three unit exposure areas U that overlap each other
(1,1), U (5,1) and U (9,1) are exemplarily shown by broken lines, one-dot chain lines and solid leader lines, respectively.

Here, the relative position of each unit exposure area U (m, n) is represented by the exposure point CN (m, n) which is the center of the unit exposure area U (m, n).
1) is the exposure point CN (1,
The exposure point CN (9,1) at the third exposure position is (+ 2a, -2) apart from the exposure point CN (1,1) at the first exposure position.
Only b) will exist. The distance between adjacent exposure points on each line is the unit exposure area U.
It matches the size C (= 20 μm) of (m, n).

As described above, when the moving distance is the sum of four times the side length C of the unit exposure area U (m, n) and the distance a, the distances a and b are appropriately selected. , An area C of the same size as each unit exposure region U (m, n)
The exposure points can be uniformly distributed in C.

For example, as shown in FIG. 6, an area C × C (= 20 μm ×) having the same size as the unit exposure region U (m, n).
In order to distribute 240 exposure points within 20 μm), it is necessary to arrange 16 along the X axis and 15 along the Y axis, and the distances a and b can be calculated by the following formulas. Determined. a = C / 16 = 20 μm / 16 = 1.25 μm b = C / 240 = 20 μm / 240 = 0.0833 μm

Needless to say, the distance b is 0.0
Setting to 833 μm means that the drawing table 16
Of the drawing table 16 so that each unit exposure region U (m, n) shifts to the negative side of the Y-axis by 0.0833 μm when is moved to the negative side of the X-axis by a distance (A + a = 81.25 μm). It is nothing but setting the inclination angle α.

In FIG. 6, the exposure point indicated by reference numeral CN (1,1) is, for example, the first exposure position at the first exposure position.
Units obtained by the beginning of the micro-mirror M of the first line of the exposure unit 20 ₀₁ (1,1) exposure area U (1,
When those of 1), as is clear from the foregoing description, the exposure point CN (5,1) is the top of the micromirror M of the fifth line of the first exposure unit 20 ₀₁ in the second exposure position ( 5, 1) unit exposure area U obtained by
(5, 1), and the exposure point CN (9, 1) is the third
Becomes round eyes exposed first exposure unit at position 20 ₀₁ of the ninth line of the top of the micromirror M (9,1) unit exposure regions obtained by U (9,1).

Further, the exposure point CN (61, 61, distant from the exposure point CN (1, 1) by a distance (+ 15a, -15b)).
1) is the center of the unit exposure area U (61,1) obtained by the micromirror M (61,1) at the head of the 61st line at the 16th exposure position, and the exposure point CN
The exposure point CN (66, 1), which is separated from (1, 1) by the distance (0, -16b), is the 66th position at the 17th exposure position.
It is the center of the unit exposure area U (66,1) obtained by the micromirror M (66,1) at the head of the line. Similarly, the distance (0, -224) from the exposure point CN (1, 1)
The exposure point CN (911,1) separated by b) is the unit exposure area U obtained by the micromirror M (911,1) at the head of the 911th line at the 241st exposure position.
The exposure point CN, which is the center of (911,1) and is separated from the exposure point CN (1,1) by a distance (15a, -239b).
(975,1) is the 97th position at the 240th exposure position.
It is the center of the unit exposure area U (975, 1) obtained by the micromirror M (975, 1) at the beginning of the 5 lines.

Thus, 15 exposure units 20 _01-
20 ₁₅ for the drawing table 16 X
When the negative side of the axis is moved intermittently, their exposure unit 20 _{01-20 15} individual micromirrors M (m,
n) the center of the unit exposure area U (m, n) obtained by
That is, the exposure points CN (m, n) are arranged over the entire drawing surface 32 at the pitches a and b along the X axis and the Y axis, respectively. 240 in a region C × C (20 μm × 20 μm) having the same size as each unit pixel region.
The individual exposure points are evenly distributed.

Of course, it is also possible to distribute the individual exposure points in the exposure units 20 _{01 to} 20 ₁₅ in a higher density over the entire drawing surface 32.
When the centers of 480 unit exposure areas are uniformly arranged within an area of 0 μm × 20 μm, the distance A is set to twice the size C of the unit exposure area (40 μm), and the distances a and b are 1 respectively. 0.25 μm / 2, 0.833 μm /
Set to 2.

Further, in the example shown in FIG. 6, 15 exposure points are arranged in parallel along the Y axis, but the distances a and b are set.
It is also possible to arrange the exposure points obliquely along the Y axis by slightly changing the value of.

As described above, in the multiple-exposure drawing apparatus 10 of the present embodiment, when the circuit pattern is drawn based on the raster data of the circuit pattern, what is the pixel size of the circuit pattern data? Also, it is possible to draw the circuit pattern. In other words, it can be said that the concept of a pixel for a circuit pattern to be drawn does not exist on the side of the multiple exposure drawing apparatus 10.

For example, if the pixel size of raster data is 20
In the case of setting to 1 μm × 20 μm, if “1” is given to any 1-bit data, one pixel area (20 μm × 20
.mu.m) corresponding to each exposure point CN (m, n) corresponding to each micromirror M (m, n) is operated by the 1-bit data to rotate from the non-exposure position to the exposure position. One pixel area (20μm × 20μ
m) will undergo multiple exposures a total of 240 times.

As another example, when the pixel size of the raster data is set to 10 μm × 10 μm, if “1” is given to any 1-bit data, the 1-bit data will be added to the 1-bit data during the exposure operation. Individual exposure points CN included in the corresponding one pixel area (10 μm × 10 μm)
The micromirror M (m, n) corresponding to (m, n) is operated by the 1-bit data to be rotated from the non-exposure position to the exposure position, whereby the one pixel area (1
0 μm × 10 μm) will be subjected to multiple exposure a total of 60 times.

The exposure time, that is, the time during which the individual micromirrors M (m, n) remain at the exposure position, is determined by the number of exposures within one pixel area on the drawing surface 32 and the object to be drawn 30 (this embodiment). Then, it is determined based on the sensitivity of the photoresist layer), the light intensity of the light source device 22, and the like, and is set so that a desired exposure amount can be obtained for each one-pixel exposure region.

FIG. 7 is a control block diagram of the multiple exposure drawing apparatus 10. As shown in FIG.
Is provided with a system control circuit 34 including a microcomputer. That is, the system control circuit 34 is a central processing unit (CPU), a read-only memory (ROM) for storing programs and constants for executing various routines, and a writable / readable memory for temporarily storing operation data and the like. Memory (RA
M) and an input / output interface (I / O), and controls the overall operation of the multiple exposure drawing apparatus 10.

The drawing table 16 is driven by the drive motor 36 along the X-axis direction. The drive motor 36 is configured as, for example, a stepping motor, and its drive control is performed according to the drive pulse output from the drive circuit 38. A drive mechanism including a ball screw or the like is interposed between the drawing table 16 and the drive motor 36, as described above.
Is symbolically indicated by a dashed arrow.

The drive circuit 38 is a drawing table control circuit 40.
This drawing table control circuit 4 is operated under the control of
0 is connected to the drawing table position detection sensor 42 provided in the drawing table 16. The drawing table position detection sensor 42 detects an optical signal from the linear scale 44 installed along the movement path of the drawing table 16 to detect the position of the drawing table 16 in the X-axis direction. In FIG. 7, detection of an optical signal from the linear scale 44 is symbolically shown by a broken line arrow.

While the drawing table 16 is moving, the drawing table position detection sensor 42 sequentially detects a series of optical signals from the linear scale 44 and outputs them as a series of detection signals (pulses) to the drawing table control circuit 40. The drawing table control circuit 40 appropriately processes the series of detection signals input thereto, and creates a series of control clock pulses based on the detection signals. Drawing table control circuit 40
Outputs a series of control clock pulses to the drive circuit 38, and the drive circuit 38 creates drive pulses for the drive motor 36 in accordance with the series of control clock pulses. In short, the drawing table 16 can be moved along the X-axis direction with accuracy according to the accuracy of the linear scale 44. Note that such a drawing table 16
The movement control itself is well known.

As shown in FIG. 7, the drawing table control circuit 40 is connected to the system control circuit 34, whereby the drawing table control circuit 40 is controlled by the system control circuit 34. On the other hand, a series of detection signals (pulses) output from the drawing table position detection sensor 42 are also input to the system control circuit 34 via the drawing table control circuit 40, whereby the system control circuit 34 causes the system control circuit 34 to display the X-axis of the drawing table 16. The position of movement along can be constantly monitored.

The system control circuit 34 is a LAN
It is connected to a CAD station or a CAM station via (Local Area Network), and the vector data of the circuit pattern created there is transferred to the system control circuit 34 from the CAD station or the CAM station. System control circuit 34
A hard disk device 46 is connected as a data storage means to the HDD, and when the vector data of the circuit pattern is transferred from the CAD station or the CAM station to the system control circuit 34, the system control circuit 34 once outputs the vector data of the circuit pattern to the hard disk device 46. Write to and store. The system control circuit 34 also includes a keyboard 4 as an external input device.
8 is connected, and various command signals, various data and the like are transmitted via the keyboard 48 to the system control circuit 34.
Entered in.

The raster conversion circuit 50 is operated under the control of the system control circuit 34. Prior to the drawing operation, the vector data of the circuit pattern is read from the hard disk device 46 and output to the raster conversion circuit 50. This vector data is converted into raster data by the raster conversion circuit 50, and this raster data is stored in the bitmap memory. 52 is written. In short, the bit map memory 52 stores bit data represented by 0 or 1 as circuit pattern data. Data conversion processing in the raster conversion circuit 50 and bitmap memory 5
The data writing in 2 is performed by a command signal input via the keyboard 48.

The read address control circuit 58 stores bit data to be given to each exposure unit in the bit map memory 5
The data is read out from No. 2 every exposure operation and stored in the exposure data memory 54 as exposure data. Exposure data is bit data for positioning the micro-mirrors of the individual exposure units 20 ₀₁ to 20 ₁₅ to the exposure position or unexposed position. When a series of read address data is output from the read address control circuit 58 to the exposure data memory 54, predetermined bit data is output from the exposure data memory 54 according to the read address data by the DMD drive circuit 56.
Is output to, DMD drive circuit 56 to the exposure unit 20 _{01-20 15} operates independently on the basis of the bit data, performs selective exposure operation individual micromirrors of each exposure unit by which It will be. Exposure data is rewritten each time the repeated exposure operation by the exposure unit 20 _{01-20 15.} The read address data and the exposure data will be described in detail later.

In FIG. 7, the exposure operation of the individual micromirrors is symbolically illustrated by broken line arrows. Also,
Although only one exposure unit is shown in FIG. 7 in order to avoid complication of the drawing, actually 15 exposure units (20 _{01 to} 20
₁₅ ) Needless to say, they exist and are each driven by the DMD drive circuit 56.

FIG. 8 schematically shows a part of the circuit pattern data (raster data) developed on the exposure data memory 54. The line number L shown in the figure corresponds to the drawing line number along the Y axis of the circuit pattern to be drawn on the drawing surface 32, and each line includes 1280 × 15 bit data. As shown in the figure, each bit data is represented by "B", and "B" is given a value of "1" or "0" according to the circuit pattern to be drawn.

According to the present invention, the pixel size of the circuit pattern data (raster data), that is, the size of each bit data "B" can be given various sizes at the design stage of the circuit pattern. . For example, if the size of the bit data “B” is 10 μm × 10 μm, the width of the drawing line to be drawn on the drawing surface 32 is also 10
The size of bit data “B” is 20 μm ×
If it is 20 μm, the width of the drawing line is also 20 μm,
If the size of the bit data “B” is 30 μm × 30 μm, the width of the drawing line is also 30 μm.

As shown in FIG. 8, 1 included in each line
The 280 × 15 bit data is the 1
It is divided into the 1st to 15th groups. First
Eight exposure units 20 in row₀₁, 20₀₃, 20₀₅Two
0₀₇, 20₀₉, 20₁₁, 20 ₁₃And 20₁₅Each of
For the exposure operation of the
7 exposure units 20 in the second row
₀₂, 20₀₄, 20₀₆, 20₀₈, 20_Ten, 20₁₂And 2
0₁₄For each exposure operation of
It is performed according to the bit data of the group.

Address data [L _x , R _y ] as schematically shown in FIG. 9 is given to the individual bit data “B” of each group. The address data component L _x indicates the line number L (FIG. 8), and the address data component R _y
Represents the number of bits counted from the most significant bit of each group. For example, address data [00000
1, 0001] represents the bit data “B” of the most significant bit of the line number 1 of each group, and the address data [0
[00003, 0001] represents the bit data "B" of the most significant bit of the line number 3 of each group, and the address data [000001, 1278] is the 1278th bit counted from the most significant bit of the line number 1 of each group. Represents data “B” and represents address data [00000
3, 1278] represents the 1278th bit data “B” counted from the most significant bit of the line number 3 of each group, and the address data [000001, 1280] is the least significant bit of the line number 1 of each group. Represents data “B” and represents address data [000003,12
80] represents the bit data “B” of the least significant bit of the line number 3 of each group.

FIG. 10 is a block diagram showing the structure of the read address control circuit 58 shown in FIG. 7 in more detail. The read address control circuit 58 is provided with control circuits corresponding to the ₁₅ exposure units 20 _{01 to} 20 ₁₅ , respectively, but only the first control circuit 580 corresponding to the first exposure unit 20 ₀₁ is shown here. The remaining 14 control circuits will be omitted.

The first control circuit 580 is provided with an exposure point coordinate data memory 582, and this exposure point coordinate data memory 582 corresponds to the micromirrors M (m, n) arranged in a matrix of 1024 × 1280. 13107
Coordinate data of 20 exposure points CN (m, n) is stored. This exposure point coordinate data is the exposure point CN (1,1) corresponding to the first micromirror M (1,1) of the first line.
It is represented by a two-dimensional rectangular coordinate system having the origin 1), and the two axes of the coordinate system are parallel to the X axis and the Y axis, respectively. This exposure point coordinate data is given from the system control circuit 34 and updated every time the entire drawing surface 32 is drawn.

The counter 581 of the first control circuit 580 has the basic control clock pulse CLK1 and the exposure clock pulse E_CLK from the system control circuit 34.
Is input, and the output is the exposure point coordinate data memory 582.
And the exposure data memory 54.

The basic control clock pulse CLK1 is 13
The exposure clock pulse E is a pulse for controlling the timing of sequentially operating each of the 10720 micromirrors.
_CLK is a pulse for controlling the exposure start timing of the first exposure unit 20 _01. Exposure clock pulse E_C
The cycle of LK is 1310 which is the cycle of the clock pulse CLK1.
720 times or more.

The counter 581 counts the number of basic control clock pulses CLK1 and outputs the count value. This count value is the exposure clock pulse E_CL
Each time K is input, the initial value is reset to 0. Therefore, the output from the counter 581 is the exposure point coordinate data memory 582.
Alternatively, it corresponds to address data indicating the order of reading bit data to be given to each micromirror from the exposure data memory 54.

Further, the first control circuit 580 is provided with an exposure position data memory 584, and the exposure position data memory 584 changes in each exposure operation of the first exposure unit 20.
Relative position data of ₀₁ with respect to the drawing surface 32 (hereinafter referred to as exposure position data), specifically, the exposure point CN corresponding to the first micromirror M (1,1) of the first line
Coordinate data of (1, 1) is stored. The exposure position data is given from the system control circuit 34 and updated every drawing.

The exposure clock pulse E_CLK is input from the system control circuit 34 to the counter 583 of the first control circuit 580, and the number of pulses is counted. The count value is output to the exposure position data memory 584 as address data for reading the exposure position data from the exposure position data memory 584.

The exposure point coordinate data memory 582 sequentially outputs the exposure point coordinate data to the adder 586 every time the address is changed in synchronization with the clock pulse CLK1, and the exposure position data memory 584 outputs the address in synchronization with the clock pulse E_CLK. The exposure position data is output to the adder 586 each time is changed. The adder 586 adds the current exposure position data to the individual exposure point coordinate data, and outputs the sum of the two to the pixel processing circuit 588. Since the exposure position data and the exposure point coordinate data are values expressed in μm units,
The pixel processing circuit 588 converts the raster data to be drawn into data based on the pixel size PS. This data becomes the read address data [L _x , R _y ] when the raster data is read from the bitmap memory 52.

In the multiple exposure drawing apparatus 10 of this embodiment
Each exposure unit 20₀₁~ 20 ₁₅Optical element of
Convex lens 26A and collimating lens of illumination optical system 26
26B and the two convex lenses 28A of the imaging optical system 28.
And 28C, reflector 28B (see FIG. 2)
Circuit pattern can be drawn by substantially correcting the
It

The principle of distortion correction will be described with reference to FIG. Without distortion optical elements 26, 28 (abbreviated in FIG. 11), projected onto the drawing surface 32 with the first exposure unit 20 _01, the total micromirror as shown by the broken line in FIG M (1, 1 ) ~ M (102
4, 1280) and has substantially the same size and shape (rectangle) as the reflecting surface. However, the optical elements 26, 28
Since there is distortion, the entire exposure area Ua _01, which is the actual projected image, is deformed as shown by the solid line in FIG. 11, for example. In the figure, the deformation is emphasized.

Micromirror M (1,1) at the upper left corner in the figure
Will be specifically described. Conventionally, the micromirror M (1,1) is given the bit data of the circuit pattern corresponding to the region R to be originally exposed.
The projected image is distorted by the distortions of 6 and 28, and an area R ′ that is actually deviated from the area R to be exposed is exposed, resulting in the displacement of the circuit pattern.

Therefore, in this embodiment, the micro mirror M is used.
By giving the bit data of the circuit pattern corresponding to the region R ′ to (1,1) as the exposure data, the displacement of the circuit pattern is substantially offset. That is, since the exposure data given to the micro mirror M (1, 1) is a value in which the distortion is taken into consideration, the circuit pattern can be drawn with high accuracy even if the optical element of the exposure unit has the distortion.

As described above, the micromirror M (1,
The bit data given to 1) is the exposure unit 20 _01.
The read address data [L _x obtained based on the sum of the exposure point coordinate data indicating the relative position of the micro mirror M (1,1) in FIG. 2 and the exposure position data indicating the relative position of the exposure unit ₂₀₀₀₁ with respect to the drawing surface 32. , R _y ] (see FIG. 7).

[0088] In the present embodiment sets the origin at a predetermined position of the optical image, i.e. entire exposure area Ua ₀₁ projected onto the drawing surface 32 by the exposure unit 20 _01, the micro-mirror M
Relative position of optical image by (1,1), that is, exposure point CN
The position (1,1) is measured by a dedicated device (not shown) before drawing, and the measured value is stored in advance in the ROM of the system control circuit 34 as exposure point coordinate data. When drawing, this measured value is output to the exposure point coordinate data memory 582 as exposure point coordinate data.

The ROM has 15 exposure units 2
0 _{01 to} 20 ₁₅ all micromirrors M (1,1) to M (1
024, 1280) is stored.

Therefore, the exposure data memory 54 holds the bit data of the distortion-corrected circuit pattern, so that the circuit pattern can be drawn on the drawing surface with high accuracy.

As described above, in the present embodiment, the distortion correction is performed by controlling the read address for reading the raster data of the circuit pattern, and the raster data in the bitmap memory 52 is not subjected to any coordinate conversion. No need to give. Therefore, no expensive lens without distortion is used, and a mechanism for rotating the drawing table 16 or driving the optical system is not required, so that the control can be simplified.

[0092] The following individual micromirrors M (m, n) of the exposure unit 20 ₀₁ and the relationship between bit data "B" at each exposure position is described.

[0093] The exposure unit 20 ₀₁ exposure point CN exposure start position or first-time exposure position in placed units obtained by any of its micro-mirror when are exposed region U (m, n) (m , n) XY coordinate P _{[x (m), y (n)]} (1 ≤
m ≦ 1024, 1 ≦ n ≦ 1280) is expressed as follows. C is the size of the unit exposure area,
Xp (m) and Yp (n) are exposure point coordinate data. Here, b is (A +
This is the amount of movement in the Y direction when moving only a). x (m) = Xp (m) = (m-1) Cy (n) = Yp (n) = (n-1) Cb (m-1)

When the exposure unit ₂₀₀₀₁ is sequentially moved in the X-axis direction by a distance (A + a) from the first exposure position and reaches the i-th exposure position, the exposure position data Xs (i) at that time and Ys (i) is represented as follows. Here, “i” is the number of exposures. Xs (i) = (A + a) (i−1) (1) Ys (i) = 0 (2)

Therefore, the X component x (m) and the Y component y (n) of the coordinates P _{[x (m), y (n)]} when the exposure unit ₂₀₀₀₁ reaches the i-th exposure position are as follows. It is shown by the formula. x (m) = Xs (i) + Xp (m) (3) y (n) = Ys (i) + Yp (n) (4)

At the i-th exposure position, the coordinates P _{[x (m), y (n)} of the exposure point CN _{(m, n)} of the unit exposure area (U _{(m, n)} ) obtained by an arbitrary micromirror. _] Is included in a certain one-pixel area, the address [L _x , R _y ] of the bit data “B” corresponding to that one-pixel area is calculated by the above two equations (3) and (4). The result can be expressed by the following formula. L _x = INT [x (m) / PS] +1 (5) R _y = INT [y (n) / PS] +1 (6) Here, in general, when division e / f is performed, The operator INT [e / f] represents the quotient of division e / f, and 0 ≦ e <f
, INT [e / f] = 0 is defined. Further, "PS" represents the size of the bit data "B".

Thus, at the i-th exposure position, the coordinate P
_The micromirror corresponding to _{[x (m), y (n)]} is (5) above.
The operation is performed in accordance with the bit data “B” of the address [L _x , R _y ] which is determined by the calculation results of the expressions and (6).

The calculation result of the above equation (3), that is, the coordinate P
_When the calculation result of the X component of _{[x (m), y (n)]} has the following relationship, x (m) <0 coordinate P _{[x (m), y (n)]} is still on the drawing surface 32. This means that you have not entered the drawing area above. Therefore, in this case, there is no bit data for operating the micromirror corresponding to the coordinate P _{[x (m), y (n)]} , and at this time, the micromirror follows dummy data “0”. Be operated.

Further, the calculation result y of the above equation (4)
(N), that is, when the calculation result of the Y component of the coordinate P _{[x (m), y (n)]} has the following relationship, y (n) <0 coordinate P _{[x (m), y (n )]} Crosses the negative boundary line along the Y axis of the drawing area. Therefore, in this case as well, the coordinate P
There is no bit data for operating the micromirror corresponding to _{[x (m), y (n)]} , and at this time, the micromirror is operated according to the dummy data “0”.

[0100] Other exposure units 20 ₀₃ - in the first row
It is possible to determine which bit data “B” should be used to operate any micromirror included in 20 ₁₅ in the exposure operation in the same manner as in the above case.
However, in that case, the exposure unit 20 is used in the above calculation.
_03, 20 _05, 20 ₁₅ each must it be considered that is remote to the positive side along the Y axis from the coordinate origin than the exposure unit 20 _01. In addition, it is also determined in the same manner as in the above case which bit data “B” should be used to operate the arbitrary micromirror of each of the exposure units 20 ₀₂ , 20 ₀₄ , and 20 ₁₄ in the second column. it is possible to, but in that case, the exposure unit 20 ₀₂ during operation of the above, 20 _04, 20 ₁₄ Further on the negative side respectively along the X-axis from the coordinate origin than the exposure unit 20 ₀₁ It must be taken into account the positive separation along the Y-axis.

Referring to FIG. 12, there is shown a flowchart of a drawing routine executed by the system control circuit 34. The execution of this drawing routine is started by turning on a power switch (not shown) of the multiple exposure drawing apparatus. .

In step S1901, the keyboard 48
It is determined whether or not the drawing start key assigned above is operated. Before the drawing start key is operated, the circuit pattern data (vector data) is converted into raster data, and the circuit pattern data (raster data) has already been expanded in the bitmap memory 52. Various data necessary for executing the routine, such as the distance A, the distance a, the drawing time, and the moving speed of the drawing table 16, are input via the keyboard 48 and already stored in the RAM of the system control circuit 34. Be present.

When the operation of the drawing start key is confirmed in step S1901, the flow advances to step S1902, in which the drive motor 36 is started and the drawing table 16 is moved from the origin position toward the negative side of the X axis at a predetermined speed. Can be moved. In other words, so that the exposure unit 20 _{01-20 15} moves to the positive side of the X axis with respect to the drawing table 16. It should be noted that here, an object to be drawn is set at a predetermined position on the drawing table 16, and the drawing start position on the drawing surface of the object to be drawn is XY at the origin position of the drawing table 16.
It is assumed to be specified with respect to the coordinate system.

In step S1903, the flag F is initialized to "0" and the counter i is initialized to "1". The flag F is the exposure unit ₂₀₀₀₁ , 2 in the first row.
0 ₀₃ , ..., 20 ₁₅ is a flag for instructing whether or not the drawing start position (that is, the first exposure position) of the drawing surface 32 of the drawing object 30 placed on the drawing table 16 is reached, Exposure unit ₂₀₀₀₁ , ₂₀₀₃ , ... 20 _{15 in} the first row
When it is confirmed that has reached the first exposure position, the flag F is rewritten from "0" to "1". Further, the counter i counts the number of exposure operations performed by the drawing apparatus, and therefore the counter i is set to "1" as an initial value.

After the initialization of the flag F and the counter i, the flow proceeds to step S1904, where the read address creation processing for creating the address data of the bit data "B" to be read from the bitmap memory 52 at the time of the first exposure operation. Is executed.

In step S1905, it is determined whether the flag F is "0". At the present early stage, F
Since = 0, the process proceeds to step S1906, where the first column of the exposure unit 20 _01, 20 _03, ... 20 ₁₅ whether the host vehicle has reached the start position or first-time exposure position drawing is monitored. The first time the first column of the exposure unit 20 ₀₁ to the exposure position, 20 _03, ... 20 the ₁₅ reaches the is confirmed, the process proceeds to step S1907, where the flag F is rewritten from "1" to "0" . Then, step S1908.
Then, the drive of the drive motor 36 is stopped and the movement of the drawing table 16 is stopped.

In step S1909, the read address control circuit 58 outputs the address data [L _x , R _y ] created by the execution of the read address creation process (step S1904) to the bit map memory 52, and thereby the bit data is generated. Predetermined bit data "B" is read from the map memory 52 and output to the DMD drive circuit 56, thus exposing units 20 ₀₁ to 18 ₈
The first exposure operation is performed according to the read bit data "B".

[0108] In the first round exposure operation, the first column of the exposure unit 20 _01, 20 _03, ... 20 ₁₅ center of the unit exposure regions obtained by the second line after the micromirrors along the Y axis of the drawing since not yet invaded the drawing area on the surface 32, the first column of the exposure unit 20 _01, 20 _03,
The micromirrors of the first line along the Y axis of 20 ₁₅ are operated, and the micromirrors of the second and subsequent lines are operated according to the dummy data “0”. At this point, the exposure unit (2
Since 0 ₀₂ , 20 ₀₄ , ... 20 ₁₄ ) have not reached the drawing start position, the exposure units (20 ₀₂ , 2
The individual micromirrors 0 ₀₄ , ..., 20 ₁₄ ) are only operated according to the dummy data “0”, and the exposure operation by the exposure units (20 ₀₂ , 20 ₀₄ , ..., 20 ₁₄ ) in the second row is also substantially effective. Will never be done.

In step S1910, it is monitored whether or not a predetermined exposure time has elapsed. If it is confirmed that the predetermined exposure time has elapsed, the flow advances to step S1911, where the exposure units 220 ₀₁ , ₂₀₀₃ , ... 20 ₁₅ The exposure operation by is stopped. Then, the process proceeds to a step S1912, whether the drawing of the circuit pattern by the exposure unit 20 _{01-20 15} is completed is determined.

Of course, at this point in time, the drawing of the circuit pattern has not been completed, so the flow advances to step S1913, where the drawing table 16 is again moved toward the negative side of the X axis. Then, in step S1914,
Therefore the count number of the counter i is only incremented "1", the exposure unit 20 _{01-20 15} provided to the second exposure operation by, then returns to step S1904.

In step S1904, the read address creating process is executed again, and at this time, the address data of the bit data "B" to be read from the bitmap memory 52 at the time of the second exposure operation is created. Then
In step S1905, it is determined whether the flag F is "0". Since F = 1 at this point, the process advances from step S1905 to step S1915, where it is monitored whether or not the drawing table 16 has moved by the distance (A + a). When it is confirmed that the movement distance of the drawing table 16 has reached the distance (A + a), the process proceeds to step S1908, in which the drive motor 36 is stopped and the movement of the drawing table 16 is stopped, and then in step S1909. The second exposure operation by the exposure units 20 _{01 to} 20 ₁₅ is performed according to the read bit data “B”.

[0112] In summary, until it is confirmed that drawing of the circuit pattern by the exposure unit 20 _{01-20 15} in step S1912 is completed, the drawing table 16 is distance (A
+ A) every time the exposure unit 20 _{01 to} 20
_The exposure operation by ₁₅ is sequentially repeated.

In step S1912, the exposure unit 20 ₀₁
When it is confirmed that the drawing of the circuit pattern by 20 to ₁₅ is completed, steps S1912 to S191
6, the drive motor 36 is reversely driven there, and the drawing table 16 is returned toward its origin position. Next, in step S1917, it is monitored whether or not the drawing table 16 has reached the origin position.
When it is confirmed that the origin position has been reached, the driving of the drive motor 36 is stopped and the execution of this routine ends.

In the above-described embodiment, during the drawing operation, the drawing table 16 is stopped each time it reaches the exposure position, and the exposure operation is performed by the exposure units 20 _{01 to} 20 ₁₅ at the stop position. However, during the writing operation, the exposure unit 20 is moved under a predetermined condition while continuously moving the drawing table 16 at a constant speed without moving intermittently.
It is also possible to perform the exposure operation according to _{01 to} 20 ₁₅ . In detail, although the drawing table 16 is distance (A + a) by exposure operation by the exposure unit 20 _{01-20 15} each time the movement is started is the same as the embodiment described above, but the exposure time, It is the time during which the drawing table 16 moves a distance d smaller than the size (20 μm) of the unit exposure area obtained by the individual micromirror of each exposure unit.

By setting the exposure time in this way, not only the circuit pattern can be drawn in the same manner as in the above case, but also the drawing time required for drawing the circuit pattern can be shortened. . Another advantage of continuously moving the drawing table 16 at a constant speed during the drawing operation is that the drive system of the drawing table 16 is unlikely to fail.

[0116]

As is apparent from the above description, according to the present invention, it is possible to properly draw a predetermined pattern regardless of the size of the pixel data of the pattern data. The flexibility in designing the circuit pattern in the CAD station or the CAM station can be greatly increased by preparing only one multiple exposure apparatus according to the present invention.

Further, in the multiple exposure apparatus according to the present invention, the distortion correction of the optical element is performed by controlling the read address of the pattern data, which can be constructed at a low cost without using a lens without distortion, and is high. The circuit pattern can be drawn accurately.

Further, as one of the characteristic effects obtained by the present invention, even if some of the modulation elements in the exposure unit do not function normally, pattern drawing can be performed without causing pixel defects. Another point is that it can be done properly. Because the drawing pattern area is obtained by multiple exposure over multiple exposure operations, the total exposure amount of the drawing pattern area is sufficient even if the exposure operation of several times is not normally performed. This is because it can be obtained.

As another function and effect obtained from the multiple exposure system according to the present invention, even if there is uneven exposure due to the imaging optical system incorporated in each exposure unit, the effect of the uneven exposure is due to the multiple exposure. There is also the point that it will be made smaller.

As a further effect obtained from the multiple exposure method according to the present invention, even if the output of the light source device is low, a sufficient exposure amount can be secured for the multiple exposure, so that the light source device can be constructed at low cost. There are also points to gain.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a multiple exposure drawing apparatus according to the present invention.

FIG. 2 is a schematic conceptual diagram for explaining a function of an exposure unit used in the multiple exposure drawing apparatus according to the present invention.

3 is a plan view for explaining a drawing surface of an object to be drawn on a drawing table of the multiple-exposure drawing device shown in FIG. 1 and an exposure area by each exposure unit.

FIG. 4 is a schematic diagram for explaining the principle of a multiple-exposure drawing method executed by the multiple-exposure drawing apparatus according to the present invention, in which exposure units are provided at a plurality of exposure positions along the X axis of the XY coordinate system. It is a figure which shows the state moved sequentially.

FIG. 5 is a schematic view similar to FIG. 4, in which the exposure unit is moved a predetermined distance along the Y axis when the exposure unit is sequentially moved to a plurality of exposure positions along the X axis of the XY coordinate system. It is a figure which shows the state displaced only by time.

FIG. 6 shows how the center of a unit exposure area obtained by a predetermined micromirror of the exposure unit when the exposure unit is sequentially moved to a plurality of exposure positions according to the multiple exposure method of the present invention is distributed within the predetermined area. It is explanatory drawing which shows whether it does.

FIG. 7 is a block diagram of a multiple exposure drawing apparatus according to the present invention.

FIG. 8 is a schematic diagram showing a part of raster data of a circuit pattern to be drawn by the multiple exposure drawing apparatus according to the present invention in a state of being expanded on an exposure data memory.

9 is a schematic diagram showing a relationship between a part of the bit data shown in FIG. 8 and its read address data.

10 is a block diagram showing the inside of the read address control circuit shown in FIG. 7 in detail.

FIG. 11 is a perspective view conceptually showing the principle of distortion correction in the present embodiment.

FIG. 12 is a flowchart of a drawing routine executed by the multiple exposure drawing apparatus according to the present invention.

[Explanation of symbols]

10 Multiple-exposure drawing apparatus 16 Drawing table 20 ₀₁ , ... 20 ₁₅ Exposure unit 27 DMD element M (1,1), ... M (1024,1280) Micromirror (modulating element) 30 Drawing target 32 Drawing surface 34 System control circuit 52 bit map memory (memory means) 58 read address control circuit (exposure data generation means) 56 DMD drive circuit (modulation element control means) 580 first control circuit (calculation means)

Claims (5)

[Claims] 1. An exposure unit having a large number of modulation elements arranged in a matrix and an optical system for projecting an optical image formed by each modulation element onto a drawing surface, and holds raster data of a predetermined pattern. A memory means, a calculation means for calculating coordinate data indicating a relative position of an optical image by each of the modulation elements on the drawing surface, and reading raster data corresponding to the coordinate data,
The exposure unit is provided with exposure data generation means for generating exposure data to be given to each of the modulation elements of the exposure unit, and modulation element control means for driving and controlling each modulation element based on the exposure data. A multiple-exposure drawing apparatus, which draws the predetermined pattern on the drawing surface by performing multiple exposure. 2. The coordinate data is a sum of exposure point coordinate data indicating a relative position of each modulation element in the exposure unit and exposure position data indicating a relative position of the exposure unit with respect to the drawing surface. The multi-exposure drawing apparatus according to claim 1. 3. The exposure point coordinate data is an actual measurement value indicating a relative position of an optical image by each modulator when an origin is set in an optical image projected on the drawing surface by each exposure unit. The multiple exposure drawing apparatus according to claim 2, wherein 4. The multiple exposure drawing according to claim 2, wherein the exposure position data is a relative movement amount from an initial exposure position when the drawing surface moves relative to the exposure unit. apparatus. 5. A multiple-exposure drawing method for drawing a predetermined pattern on a drawing surface by multiple exposure using at least one exposure unit having a large number of modulators arranged in a matrix, and raster data of the predetermined pattern. In a memory means, a second step of calculating coordinate data indicating a relative position of the optical image by each of the modulators on the drawing surface, and reading raster data corresponding to the coordinate data,
A multiple-exposure drawing method comprising: a third step of generating exposure data to be given to each of the modulation elements of the exposure unit; and a fourth step of driving and controlling each modulation element based on the exposure data. .