WO2014174352A1

WO2014174352A1 - Exposure device

Info

Publication number: WO2014174352A1
Application number: PCT/IB2014/000553
Authority: WO
Inventors: 隆志奥山
Original assignee: 株式会社オーク製作所
Priority date: 2013-04-17
Filing date: 2014-04-16
Publication date: 2014-10-30
Also published as: KR102142747B1; TWI607291B; KR20150143622A; JPWO2014174352A1; TW201447502A

Abstract

The present invention is a method for accurately detecting a pattern formation position in a maskless exposure device. This maskless exposure device is equipped with a position detection unit having first and second photosensor groups that are positioned at an incline in reverse directions to one another with respect to a first scanning direction. By controlling a plurality of optical modulating elements, scanning is carried out while projecting light of first and second position detection pattern rows on the position detection unit, thereby detecting the position. The light of first and second position detection pattern rows is inclined along the directions perpendicular to that in which first and second photosensor groups are aligned, and the pattern width in the alignment direction of the first and second photosensor groups is smaller than the photosensor width, and larger than the interval between the photosensors. Said position detection pattern is scanned above the position detection unit, and the exposure position at which the level of the brightness signal outputted from the adjoining photosensors becomes the same is detected in a time series for the first series of exposure positions and the second series of exposure positions.

Description

Exposure equipment

The present invention relates to a maskless exposure apparatus that forms a pattern using a light modulation element array, and more particularly to position detection of a pattern projected on a substrate or the like.

In a maskless exposure apparatus, pattern light is projected onto a substrate by a light modulation element array such as DMD (Digital Micro-mirror Device) while moving a stage on which the substrate is mounted along the scanning direction. There, a light modulation element such as a micromirror arranged in a two-dimensional manner is used to detect the position of a projection area (exposure area) on a substrate placed on a stage and project pattern light according to the position. Control.
When a fine pattern is formed on the order of a micrometer, it is necessary to accurately detect the position of the substrate and project the pattern light without misalignment. However, due to a change in temperature of the DMD or the like, there may be a deviation in the projection position of the pattern light and an error in the pattern formation position.
In order to prevent this, a plurality of optical sensors such as photodiodes are arranged beside the stage, and a pattern for position detection is projected onto the optical sensor while scanning the stage. The exposure position is corrected by comparing the detected exposure position with reference position information prepared in advance (see, for example, Patent Document 1).
On the other hand, in order to detect the position of a movable body such as a stage with high accuracy, a method of detecting a reference position from a change in light quantity of two optical sensors is known (see Patent Document 2). Here, in order to detect the origin position of the encoder, that is, the reference position, a pair of photodiodes whose positions are symmetrically shifted along the scanning direction are arranged.
By moving the scale formed with the slits, the slit light for position detection passes over the diode pair. In the light amount change detected at this time, a position where the light amounts of the two photosensors are equal to each other is detected as a reference position.

JP 2008-134370 A JP 10-090008 A

The size of the photodiode is larger than the pattern resolution. There are individual differences in the photosensitive characteristics of the photodiodes. Therefore, even if a pattern is projected with the same light intensity, the amount of light detected is slightly different. In addition, the projected light may become unstable momentarily due to illuminance unevenness or the like, and it is difficult to detect the exposure position with high accuracy.
Further, in the exposure apparatus, the substrate is displaced in the sub scanning direction as well as the main scanning direction. Therefore, an error occurs in the position of the scanning band through which the exposure area passes in the main scanning direction and the sub-scanning direction, and the pattern accuracy is lowered.
Therefore, in a maskless exposure apparatus, accurate two-dimensional position detection is required using a photosensor such as a photodiode.

An exposure apparatus according to the present invention includes a light modulation element array in which a plurality of light modulation elements are arranged in a matrix, a scanning unit that relatively moves an exposure area by the light modulation element array with respect to a drawing object along a main scanning direction, A position detection unit is provided that includes a first photosensor group that is inclined with respect to the main scanning direction, and a second photosensor group that is inclined with respect to the main scanning direction in a direction opposite to the main scanning direction. . Here, the reverse rotation direction represents the opposite direction when the first photosensor group is inclined in one rotation direction when a line along the movement direction or the scanning direction is used as a reference.
Further, the exposure apparatus is inclined along the arrangement vertical direction of the first and second photosensor groups by controlling the plurality of light modulation elements, and along the arrangement direction of the first and second photosensor groups. An exposure operation control unit that projects light of the first and second position detection pattern rows, each pattern width being smaller than the photosensor width and larger than the photosensor interval, to the first and second photosensor groups, respectively. Prepare.
When the exposure area is relatively moved by moving the stage or the like, when one position detection pattern passes through the photosensor, the luminance signal level increases, follows constant, and decreases. At the same time, there is an intersecting portion in the graph of the luminance signal level of each other output from the adjacent photo sensor while the light of one position detection pattern passes through the adjacent photo sensor.
Then, the position detection unit determines the exposure positions at which the levels of the luminance signals output from the adjacent photosensors become equal as the first and second position detection pattern rows pass through the first series of exposure positions and the second series. A series of exposure positions are detected in time series. Thereby, the position detection unit can calculate a two-dimensional exposure position from the detected first and second series of exposure positions. Here, the two-dimensional exposure position can be defined based on, for example, two-dimensional coordinates defined along the main scanning direction and the sub-scanning direction.
The position detection unit of the present invention detects an exposure position where the level of the luminance signal output from the adjacent photosensor becomes equal while the light of one position detection pattern passes through the adjacent photosensor, and the position detection pattern A series of exposure positions are detected in time series as light passes through the row. Here, the exposure position represents a relative position on the stage of a predetermined position detection pattern, and is represented by, for example, position coordinates along the scanning direction defined on the stage.
By detecting a plurality of exposure positions, it is possible to perform position correction that is not affected by illuminance unevenness, individual differences among photosensors, and the like. For example, the exposure apparatus may be provided with a correction unit that corrects the exposure reference position based on a series of detected exposure positions and a predetermined standard exposure position. Here, the standard exposure position can be expressed by, for example, position coordinates determined on the drawing data. Further, as the exposure reference position, for example, a drawing start position is determined.
Furthermore, since the exposure position is detected two-dimensionally, exposure data is corrected not only for the drawing start position but also for the exposure position along the sub-scanning direction, so that the drawing area does not partially overlap and is accurate. A pattern can be formed. As for the calculation of the two-dimensional exposure position, the first and second series of exposure positions are detected in advance as vector exposure positions along the sensor arrangement direction, and representative exposure positions (averages) are obtained for each photosensor group. 2), the two-dimensional exposure position coordinates along the main scanning direction and the sub-scanning direction can be obtained.
The arrangement interval of the photosensors, the pattern interval of the pattern row, and the like can be arbitrarily set. For example, the inclination arrangement angle α with respect to the moving direction of the first photosensor group or the main scanning direction is in a range of 30 ° ≦ α ≦ 60 °, and the inclination arrangement angle β of the second photosensor group is −60 ° ≦ β. It falls within the range of ≦ −30 °. In particular, the first and second photosensor groups can be inclined at + 45 ° and −45 °, respectively, and can be arranged symmetrically with respect to the moving direction or the main scanning direction. However, the movement direction represents the movement direction of the drawing object such as the substrate (the direction opposite to the main scanning direction). In addition, it is possible to arrange a plurality of photosensors at regular intervals along the scanning direction, and to configure the position detection pattern sequence with position detection patterns arranged at regular intervals.
The shape of each pattern in the pattern row is also arbitrary, and any shape can be used as long as the photosensor can individually detect the passage of each position detection pattern. Specifically, the pattern width, the inclination angle, and the like may be determined so that pattern light is projected onto both adjacent photosensors when one position detection pattern passes between the photosensors. For example, it is possible to project light of a pattern row in which bar-shaped patterns are arranged in the main scanning direction.
The number of exposure positions detected depends on the number of photosensors and the number of patterns in the pattern row. For example, it is possible to install two or more photosensors and configure the position detection pattern sequence by two or more position detection patterns. In this case, each position detection pattern is detected between a plurality of adjacent sensors, and a plurality of exposure positions are detected by passing the pattern row between the same adjacent sensors.
The first and second photo sensor groups can be arranged along the sub-scanning direction or along the main scanning direction in one scanning band region. When the first and second photosensor groups are arranged along the sub-scanning direction, the exposure operation control unit may project the light of the first and second position detection pattern rows at the same time along the sub-scanning direction. As a result, the exposure position can be detected in an adjacent region without switching the pattern. On the other hand, when the first and second photosensor groups are arranged along the main scanning direction, the exposure operation control unit projects light of the first position detection pattern row when the exposure area passes through the first photosensor group. Then, when the exposure area passes through the second photosensor group, the light of the second position detection pattern row is projected. Thereby, a series of first and second exposure positions can be detected on the same main scanning line.
As for the position correction, it is possible to obtain a difference between each detected exposure position and the target standard exposure position and calculate a typical correction value such as an addition / weighted average value. Alternatively, a representative exposure position can be calculated from a series of detected exposure positions.
The position detection unit can adopt various configurations, and the luminance signal from a plurality of photosensors may be detected by the control unit of the exposure apparatus, or the position detection unit and the position calculation unit at the previous stage. May be provided. In order to accurately detect the timing at which the luminance signal levels match, for example, the position detection unit calculates the exposure position according to the detected pulse signal and the pulse signal generation unit that generates the pulse signal at the same timing of the luminance signal A position calculating unit.
Various arrangements of the pulse signal generation unit and the position detection unit are possible. For example, when a plurality of exposure heads are provided and position correction is performed for each exposure head, a pulse signal generation unit can be provided on the stage.
When a series of exposure positions is detected by a pulse signal, it is preferable to prevent the pulse signals from being generated simultaneously. Therefore, the detection exposure operation control unit may project the light of the position detection pattern sequence so as to generate a series of detected pulse signals at different timings. For example, the exposure operation control unit can project the light of the position detection pattern row at a predetermined pattern pitch so that a series of pulse signals are generated at substantially constant time intervals.
An exposure method according to another aspect of the present invention includes: moving an exposure area by a light modulation element array in which a plurality of light modulation elements are arranged in a matrix; relative to the object to be drawn along the main scanning direction; A first photosensor group that is inclined and a second photosensor group that is inclined in the reverse rotation direction with respect to the main scanning direction are arranged, and an arrangement of the first and second photosensor groups. First and second position detection pattern rows that are respectively inclined along the vertical direction and each pattern width along the arrangement direction of the first and second photosensor groups is smaller than the photosensor width and larger than the photosensor interval. Are projected onto the first and second photosensor groups, respectively, and in the first and second photosensor groups, the level of the luminance signal output from the adjacent photosensors The equal exposure position, detecting in time series as the first series of the exposure position and the second series of exposure positions.

According to the present invention, the pattern formation position can be accurately detected in the maskless exposure apparatus.

1 is a schematic perspective view of an exposure apparatus according to a first embodiment. It is a schematic block diagram of an exposure apparatus. It is the figure which showed the photo sensor group and the position detection pattern row | line | column. It is the figure which showed the width | variety of a photosensor and a pattern. It is the figure which showed the light quantity change of the light which injects into a photosensor. It is the figure which showed the light quantity change of the adjacent photo sensor. It is the figure which showed the output timing of the pulse signal in time series. It is the figure which showed the photo sensor group and position detection pattern in 2nd Embodiment. It is the figure which showed the positional relationship of the position detection pattern in a 1st photosensor group, and a photosensor. It is the figure which showed the positional relationship of the position detection pattern and photosensor in a 2nd photosensor group. It is the figure which showed the photo sensor group and position detection pattern row | line in 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic perspective view of an exposure apparatus according to the first embodiment. FIG. 2 is a schematic block diagram of the exposure apparatus.
The exposure apparatus (drawing apparatus) 10 is a maskless exposure apparatus that forms a pattern by irradiating light onto a substrate W coated or pasted with a photosensitive material such as a photoresist. It is installed.
A stage 12 on which a substrate W is mounted is installed on the base 14 so as to be movable along the scanning direction. The stage drive mechanism 15 can move the stage 12 along the main scanning direction X and the sub-scanning direction Y.
The exposure apparatus 10 includes a plurality of exposure heads that project pattern light, and only one exposure head 18 is illustrated here. The exposure head 18 includes a DMD 22, an illumination optical system, and an imaging optical system (all not shown), and the other exposure heads are similarly configured. The light source 20 is constituted by a discharge lamp (not shown), for example, and is driven by a light source driving unit 21.
When CAD / CAM data composed of vector data or the like is input to the exposure apparatus 10, the vector data is sent to the raster conversion circuit 26, and the vector data is converted into raster data. The generated raster data is temporarily stored in a buffer memory (not shown) and then sent to the DMD driving circuit 24.
The DMD 22 is a light modulation element array (light modulator) in which minute micromirrors are two-dimensionally arranged, and each micromirror selectively switches the light reflection direction by changing the posture. By controlling the posture of each mirror by the DMD driving circuit 24, light corresponding to the pattern is projected onto the surface of the substrate W through the imaging optical system.
The stage drive mechanism 15 moves the stage 12 in accordance with a control signal from the controller 30. The position detection unit 28 is installed near the end of the stage 12, and includes a photosensor group PD including a plurality of photosensors, and a pulse signal generation unit 29. The position calculation unit 27 calculates the exposure position, that is, the position of the substrate W, based on the signal sent from the position detection unit 28.
During the exposure operation, the drawing table 12 moves along the scanning direction X at a constant speed. A projection area (hereinafter referred to as an exposure area) by the entire DMD 22 relatively moves on the substrate W as the substrate W moves. The exposure operation is performed according to a predetermined exposure pitch, and the micromirror is controlled to project pattern light in accordance with the exposure pitch.
By adjusting the control timing of each micromirror of the DMD 22 according to the relative position of the exposure area, the light of the pattern to be drawn is sequentially projected at the position of the exposure area. Then, a pattern is formed on the entire substrate W by drawing the entire substrate W with a plurality of exposure heads including the exposure head 18.
As an exposure method, not only a continuous movement method that moves at a constant speed, but also step and repeat movements that move intermittently are possible. Also, multiple exposure (overlap exposure) in which the projection area at the time of exposure shot is partially overlapped is possible.
In the stage before starting the exposure operation, correction processing relating to the exposure start position is performed in order to form a pattern at an accurate position. While moving the stage 12 at a constant speed, light of a pattern for position detection is projected. The controller 30 corrects the exposure start position based on the position information sent from the position calculation unit 27.
Hereinafter, the detection and correction of the exposure position will be described with reference to FIGS.
FIG. 3 is a diagram illustrating a photosensor group and a position detection pattern sequence. FIG. 4 is a diagram showing the width of the photosensor and the pattern. FIG. 5 is a diagram showing a change in the amount of light incident on the photosensor.
The photosensor group PD includes N photosensors P1, P2,..., PN, and is arranged in the scanning direction at equal intervals of the arrangement pitch T. On the other hand, the position detection pattern row LP is composed of a series of bar-shaped patterns L1, L2, L3,. M patterns L1, L2, L3,... LM are arranged at equal intervals with a pattern pitch J.
The pattern width K of each of the patterns L1, L2, L3,... LM is shorter than the photosensor width Z. Therefore, when the pattern L1 at one head position passes through the photosensors P1 and P2, the level of the luminance signal output from the photosensors P1 and P2, that is, the amount of light received by the photosensor is as shown in FIG. Followed by increasing, constant, decreasing.
More specifically, the light quantity of the photosensor P1 increases as a part of the pattern L1 moves on the photosensor P1 due to the movement of one pattern L1. While the entire pattern L1 is positioned on the photosensor P1, the light quantity detected by the photosensor P1 is constant at the maximum light quantity. Then, as the moving front end side of the pattern L1 exceeds the photosensor P1 and moves between the photosensors P1 and P2, the light amount of the photosensor P1 decreases.
Similarly, in the photosensor P2 located next to the photosensor P1 in the scanning direction, the light amount increases, is constant, and decreases. This change in light amount occurs with a delay corresponding to the pattern pitch T with respect to the photosensor P1. On the other hand, the width K of the pattern L1 is larger than the interval B between adjacent photosensors. Therefore, while the pattern L1 passes between the photosensors P1 and P2, a period Q in which the light amount decrease of the photosensor P1 and the light amount increase of the photosensor P2 overlap occurs (see FIG. 5).
In this period Q, the positions and points where the light amounts of the photosensors P1 and P2 match are detected as exposure positions. Specifically, the pulse signal generation unit 29 generates a pulse signal at the light intensity coincidence timing, and detects the position of the pattern L1, that is, the position of the substrate W. Thereby, it is possible to detect an exposure position that requires an order that is equal to or smaller than the photosensor size width Z.
After the light quantity coincidence point is detected when the pattern L1 passes, the light quantity coincidence point is also detected for the patterns L2, L3,. As a result, M exposure positions are detected between the photosensors P1 and P2.
Furthermore, not only the photosensors P1 and P2, but also the adjacent photosensors Pj and Pj + 1 (1 ≦ j ≦ N−1), the light quantity coincidence point is detected as the exposure position. Accordingly, when M patterns L1, L2,... LM pass over N photosensors P1, P2,..., PN, (N-1) .times.M exposure positions are detected. That is, the M exposure positions are detected in the gaps of (N−1) photosensors.
FIG. 6 is a diagram showing a change in the light amount of the adjacent photosensors P1 and P2. FIG. 7 is a diagram showing the output timing of the pulse signal in time series.
The pattern pitch J of the position detection pattern row L is determined so as to satisfy the following expression. However, T represents the photosensor pitch, SA represents the total number of detected pulses, M represents the number of patterns, and N represents the number N of photosensors.
J = T / M + T
SA = (N−1) M (1)
By setting the pattern pitch J in this way, the output timings of a series of pulse signals output between adjacent photosensors do not overlap, but are output in time series at substantially constant intervals. FIG. 6 shows a pulse signal output at the pulse pitch PS.
Based on a series of output pulse signals, the exposure position is calculated and the exposure start position is corrected. In the position calculation unit 27 including a pulse counter, a latch circuit, and the like, the exposure position of each pattern, that is, on the substrate, is determined from a series of pulse signals sequentially output in time series based on the moving speed of the stage 12, encoder signals, and the like. X position coordinates are calculated.
The controller 30 sequentially calculates the difference between the exposure position calculated from each pulse signal and the preset standard exposure position. As standard exposure positions, position coordinates of intermediate points between (N-1) adjacent photosensors are stored and set in advance.
After calculating correction values for all detected exposure position coordinates, the average value is obtained. The exposure position is corrected by this average value. When actual drawing processing is performed, drawing is started by shifting the exposure position by the correction value. Here, the exposure position is corrected as the reference position of the substrate W for each of the plurality of exposure heads.
As described above, according to the first embodiment, the position detection unit 28 in which the plurality of photosensors P1 to PN are arranged at equal intervals along the scanning direction X is provided on the stage 12, and along the scanning direction X. A position detection pattern row L composed of bar / slit patterns L1 to LM arranged at equal intervals is projected during scanning. Then, the positions at which the received light amounts of the adjacent photosensors are equal during the pattern row detection are detected in time series as exposure positions, and the reference position is determined based on the detected (N−1) × M exposure positions. It is corrected.
By projecting pattern rows onto a plurality of photosensors arranged in the scanning direction, exposure positions are detected at a number of locations, and a number of exposure positions are also detected at the same point. This makes it possible to accurately detect the exposure position without being affected by irregularities in the illumination of the pattern light, the effects of fluctuations in the amount of light due to disturbance, individual differences in the photosensor (difference in output characteristics of the photosensor), changes over time, etc. Can be done in one scan. In addition, an accurate exposure position can be detected without using a device that is difficult in terms of device structure, such as minimizing the size of the photosensor and the interval between photosensors, and does not require a costly configuration.
Since the exposure position is detected by generating a pulse signal, the configuration of the detection unit can be simplified on the stage. In particular, when a plurality of exposure heads are arranged, it is possible to generate a pulse signal in each exposure head and provide the position calculation unit as a single circuit, and the configuration of the position detection unit can be simplified. Further, since the pattern pitch and the like are set so that the pulse signals output in time series are not output simultaneously or overlapping, it is possible to detect a large number of exposure positions.
The number of patterns in the pattern row, the pattern shape, and the number of photosensors are arbitrary. Considering that the exposure position is detected a plurality of times between different photosensors, a pattern row composed of two or more patterns may be configured, and a photosensor group may be configured with three or more photosensors. In addition, the photosensor may be configured to be detachable.
The position detection pattern shape, pattern pitch, photosensor pitch, photosensor width, and pattern width are also set so that a light quantity change occurs between adjacent photosensors when each pattern passes, and a light quantity coincidence point can be extracted. That's fine. That is, the pattern width may be smaller than the photosensor width and larger than the distance between adjacent photosensors.
The exposure position is calculated by first calculating a representative exposure position such as an average value from a series of detected exposure positions, and correcting the exposure start position based on the difference between the average value and the standard value. May be. It is also possible to configure to detect the exposure position where the light amount becomes equal by a configuration other than the generation of the pulse signal.
Next, a second embodiment will be described with reference to FIGS. In the second embodiment, a two-dimensional exposure position is detected in the main scanning direction (X direction) and the sub-scanning direction (Y direction). Other configurations are substantially the same as those in the first embodiment.
FIG. 8 is a diagram illustrating a photosensor group and a position detection pattern in the second embodiment. The arrangement and position detection pattern of the photosensor group in the second embodiment will be described with reference to FIG.
The position detection unit 128 includes a first photosensor group 128A and a second photosensor group 128B, and is arranged near the end of the stage 12 along the sub-scanning direction. In the first photosensor group 128A, a plurality of photosensors are arranged at equal intervals along a direction inclined by + 45 ° with respect to the moving direction (the direction opposite to the main scanning direction).
On the other hand, in the second photosensor group 128B, a plurality of photosensors are arranged at equal intervals along a direction inclined by −45 ° with respect to the moving direction. The sensor arrangement direction of the second photosensor group 128B corresponds to the reverse rotation direction of the first photosensor group 128A with respect to the movement direction / main scanning direction. In FIG. 8, the first photosensor group 128A is tilted counterclockwise from the moving direction, while the second photosensor group 128B is tilted clockwise.
The first photosensor group 128A and the second photosensor group 128A are arranged in the same scanning band (a region where the exposure area passes during scanning), and here, they are arranged in parallel along the sub-scanning direction. As described above, they are spaced apart from each other in adjacent scanning bands.
When detecting the exposure position, the first position detection pattern row HP is projected onto the first photosensor group 128A, and the second position detection pattern IP is projected onto the second photosensor group 128B. Accordingly, the first and second position detection patterns are projected side by side along the sub-scanning direction. The first position detection pattern row HP includes four bar-shaped position detection patterns H1 to H4. The position detection patterns H1 to H4 are inclined along the direction perpendicular to the arrangement direction (+ 45 °) of the first photosensor group 128A, and are arranged at equal intervals along the movement direction / main scanning direction.
Similarly, the second position detection pattern array IP includes four bar-shaped position detection patterns I1 to I4, and the position detection patterns I1 to I4 are perpendicular to the arrangement direction (−45 °) of the second photosensor group 128B. And are arranged along the moving direction / main scanning direction at equal intervals.
The first photosensor group 128A and the second photosensor group 128B are arranged at a predetermined interval in the sub-scanning direction so as to pass the first position detection pattern array HP and the second position detection pattern IP having different patterns, respectively. ing. Each of the position detection patterns H1 to H4 and I1 to I4 has a length that intersects with all the photosensors when passing through the

photosensor groups

128A and 128B, respectively.
Even when the main scanning direction and the moving direction of the substrate shown in FIG. 8 are reversed, it is possible to similarly arrange the photosensor groups in an inclined manner. The projection pattern shape of the position detection patterns HP and IP may be determined.
FIG. 9 is a diagram illustrating a positional relationship between the position detection pattern and the photosensor in the first photosensor group. FIG. 10 is a diagram illustrating a positional relationship between the position detection pattern and the photosensor in the second photosensor group. The exposure position detection in the second embodiment will be described with reference to FIGS.
As shown in FIG. 9, when one position detection pattern H1 passes through adjacent photosensors PN and PN-1, the position detection pattern H1 and the photosensors PN and PN-1 are inclined by 45 ° with respect to the main scanning direction. Therefore, the pattern moving direction is inclined with respect to the main scanning direction. Here, the minutely displaced position detection pattern H1 is indicated by a broken line.
The relationship among the position detection pattern width K, the photosensor width Z, and the photosensor pitch T satisfies the same relationship as in the first embodiment. Therefore, the light quantity coincidence point is detected in the light quantity distribution detected between the photosensors. The position detection pattern H1 moves relative to the arrangement direction of the photosensors PN and PN-1 in an oblique direction. However, the position detection pattern H1 has a length that is sufficiently longer than the length in the long axis direction of the photosensor. . Therefore, the pattern passes through the entire area where the light amount changes.
Regarding the photosensors PN and PN-1 of the first photosensor group 128A, when the exposure position along the photosensor arrangement direction is detected, the component is represented by a vector obtained by combining the X component and the Y component. Since the sensor array direction is inclined by + 45 ° with respect to the movement direction, the exposure position vectors along the array direction are expressed as S1, X component, and Y component vectors as dX and dY, respectively. It holds.
S1 = (dX + dY) / √2 (2)
However, the direction which inclines counterclockwise with respect to the moving direction (−X direction) is positive. For the sake of convenience, the above formula is represented without using a vector code (→).
Similarly, regarding the photosensors PM and PM-1 of the second photosensor group 128B, when detecting the exposure position along the photosensor arrangement direction, the component is represented by a vector obtained by combining the X component and the Y component. Is done. When the exposure position vector along the arrangement direction is expressed as S2, the X component, and the Y component vectors as dX and dY, respectively, the following equations are established.
S2 = (dX−dY) / √2 (3)
Therefore, the X component dX and the Y component dY of the exposure position can be obtained from the above equations (1) and (2) by the following equations.
dX = (S1 + S2) / √2
dX = (S1-S2) / √2
.... (4)
Similarly to the first embodiment, when the first position detection pattern array HP and the second position detection pattern array IP pass, when the luminance level matches from the light quantity distribution of the adjacent photosensors, the pulse signal is Output in series. The time interval of the series of detected pulse signals corresponds to the distance interval along the photosensor array direction (+/− 45 °).
Therefore, when a series of pulse signals are detected in each of the first photosensor group 128A and the second photosensor group 128B, three exposure positions S1 and S2 along the sensor array direction are calculated. From the calculated series of exposure positions, representative values (average values, etc.) relating to S1 and S2 are calculated, and the X component and Y component of the exposure position are calculated by the above equation (4).
The calculated representative value is compared with the X and Y components at the reference exposure position, and correction values for the X and Y components are obtained. Then, based on the correction value, the exposure start position is corrected in the main scanning direction and the sub-scanning direction. Alternatively, the exposure data may be corrected based on the correction value and the exposure operation may be executed.
As described above, according to the second embodiment, the first photosensor group 128A and the second photosensor group 128B are arranged so as to be inclined + 45 ° / −45 ° with respect to the main scanning direction, and the inclination directions are mutually different. It faces in the opposite direction. Then, the first position detection pattern row HP inclined in the direction perpendicular to the sensor arrangement of the first photosensor group 128A is projected onto the first photosensor group 128A, and the first photosensor group 128B is projected onto the first photosensor group 128A. The second position detection pattern array IP tilted in the direction orthogonal to the sensor array of one photosensor group 128A is projected.
A series of exposure positions are detected during scanning by arranging two photosensor groups in different directions and projecting a position detection pattern row inclined according to the sensor arrangement direction. Based on the position information along the sensor arrangement direction from the two photosensor groups, the exposure position of (X, Y coordinates) along the main scanning direction and the sub-scanning direction is calculated, and a correction value is obtained. . Thereby, the movement distance along the sub-scanning direction of the stage is corrected together with the drawing start position, or the exposure data is corrected. In particular, by adjusting the exposure position along the sub-scanning direction, it is possible to prevent the scanning bands from overlapping and causing a step in the projection area.
In consideration of easily calculating the exposure position from the pulse signals of the two photosensor groups, the sensor arrangement direction is preferably 45 °, but may be other than that, for example, in the range of 30 ° to 60 °. When appropriately selected, the exposure position can be detected with sufficient accuracy for practical use. Moreover, the magnitude | sizes of the inclination angle may mutually differ.
Specifically, the first and second photosensor groups 128A are inclined with respect to the moving direction at an angle α satisfying 0 ° <α <90 °, while the second photosensor group 128B is The moving direction may be inclined at an angle β satisfying −90 ° <β <0 °. Further, it can be similarly inclined with respect to the main scanning direction.
In that case, in the above equation (4), a two-dimensional exposure position calculation formula can be derived using a trigonometric function representing the sensor arrangement direction. However, when the main scanning direction and the sub-scanning direction are defined as two-dimensional coordinate axes, and the arrangement directions of the first photosensor group and the second photosensor group are represented by vectors, the vectors are adjacent and in different quadrants. In order to exist, it is necessary to define two arrangement directions.
Next, a third embodiment will be described with reference to FIG. In the third embodiment, the first photosensor group and the second photosensor group are arranged in the same scanning band, while being arranged at intervals along the main scanning direction.
FIG. 11 is a diagram illustrating a photosensor group and a position detection pattern sequence according to the third embodiment.
The position detection unit 228 includes a first photosensor group 228A and a second photosensor group 228B. The first photosensor group 228A is inclined in the positive direction with respect to the main scanning direction, and the second photosensor group 228B is It is inclined in the reverse rotation direction. The first photo sensor group 228A and the second photo sensor group 228B are arranged in the same scan band at a predetermined interval so that the exposure area passes through both photo sensor groups when moving along one scan band. Arranged along the scanning direction.
During scanning, the position detection pattern row HP is projected while the exposure area passes through the first photosensor group 228A. Then, while the exposure area passes through the second photosensor group 228B, the position detection pattern row HP is switched to the position detection pattern row IP and projected. Thereby, a series of pulse signals are detected as in the third embodiment, and two-dimensional exposure position calculation and exposure start position correction are performed.
Various changes, substitutions and alternatives are possible with respect to the present invention without departing from the spirit and scope of the present invention as defined by the appended claims. Furthermore, the present invention is not intended to be limited to the specific embodiments of the processes, apparatus, manufacture, components, means, methods, and steps described in the specification. Those skilled in the art will appreciate from the disclosure of the present invention devices, means, and methods that perform substantially the same functions as those provided by the embodiments described herein, or that provide substantially the same effects and advantages. You will recognize it. Accordingly, the appended claims are intended to be included within the scope of such devices, means, and methods.
This application is an application claiming priority from a Japanese application (Japanese Patent Application No. 2013-086730, filed on April 17, 2013) as a basic application, and the disclosure including the specification, drawings, and claims of the basic application is referred to. Which is incorporated herein by reference in its entirety.

10 Exposure Equipment 22 DMD (Light Modulation Element Array)
28 Position detector 30 Controller

Claims

A light modulation element array in which a plurality of light modulation elements are arranged in a matrix, and
A scanning unit that moves the exposure area by the light modulation element array relative to the object to be drawn along the main scanning direction;
A position detection unit having a first photosensor group that is inclined with respect to the main scanning direction, and a second photosensor group that is inclined with respect to the main scanning direction in a direction opposite to the main scanning direction;
By controlling the plurality of light modulation elements, each pattern width is inclined along the arrangement vertical direction of the first and second photosensor groups, and along the arrangement direction of the first and second photosensor groups. An exposure operation control unit that projects light of the first and second position detection pattern rows smaller than the photosensor width and larger than the photosensor interval to the first and second photosensor groups, respectively. ,
In the first and second photosensor groups during scanning, the position detector detects exposure positions at which the levels of the luminance signals output from adjacent photosensors are equal to each other as a first series of exposure positions and a second An exposure apparatus that detects time series as a series of exposure positions.
2. The exposure apparatus according to claim 1, wherein the position detection unit calculates a two-dimensional exposure position from the detected first and second series of exposure positions.
3. The exposure apparatus according to claim 1, wherein the first and second photo sensor groups are arranged along a sub-scanning direction.
3. The exposure apparatus according to claim 1, wherein the first and second photo sensor groups are arranged along a main scanning direction.
The position detection unit is
A pulse signal generator that generates a pulse signal at the same timing of the luminance signal;
The exposure apparatus according to claim 1, further comprising: a position calculation unit that calculates an exposure position in accordance with the detected pulse signal.
4. The exposure apparatus according to claim 3, wherein the pulse signal generator is provided on the stage.
5. The exposure operation control unit projects light of the first and second position detection pattern rows so as to generate a series of detected pulse signals at different timings. The exposure apparatus according to any one of the above.
The exposure operation control unit projects light of the first and second position detection pattern rows at a predetermined pattern pitch so that a series of pulse signals are generated at substantially constant time intervals. 5. The exposure apparatus according to 5.
The exposure apparatus according to any one of claims 1 to 8, wherein the first and second photosensor groups are integrally provided on a stage on which the drawing object is mounted.
The inclination arrangement angle α with respect to the moving direction or the main scanning direction of the first photosensor group is in a range of 30 ° ≦ α ≦ 60 °,
10. The exposure according to claim 1, wherein an inclination arrangement angle β with respect to the moving direction of the second photosensor group or the main scanning direction is in a range of −60 ° ≦ β ≦ −30 °. apparatus.
Move the exposure area by the light modulation element array in which a plurality of light modulation elements are arranged in a matrix, relative to the object to be drawn along the main scanning direction,
A first photosensor group that is inclined with respect to the main scanning direction, and a second photosensor group that is inclined with respect to the main scanning direction in a reverse rotation direction with respect to the main scanning direction;
The first and second photosensor groups are inclined along the arrangement vertical direction, and the pattern widths along the arrangement direction of the first and second photosensor groups are smaller than the photosensor width. Projecting light of the first and second position detection pattern rows larger than the first and second photosensor groups,
In the first and second photo sensor groups, the exposure positions at which the levels of the luminance signals output from the adjacent photo sensors are equal are detected in time series as the first series of exposure positions and the second series of exposure positions. An exposure method characterized by: