KR102142747B1 - Exposure device - Google Patents

Abstract

The present invention is a method for accurately detecting a pattern formation position in a maskless exposure apparatus. First and second position detection patterns on the corresponding position detection unit by having a position detection unit having first and second photo sensor groups inclined in opposite directions with respect to the main scanning direction, and controlling a plurality of optical modulation elements The position is detected by scanning while projecting the light of the column. The light of the first and second position detection pattern rows is inclined respectively along the arrangement vertical direction of the first and second photo sensor groups, and the width of each pattern according to the arrangement direction of the first and second photo sensor groups is photo sensor It is smaller than the width and larger than the photo sensor interval. Then, by scanning the position detection pattern on the position detection unit, the exposure position at which the level of the luminance signal outputted from the neighboring photo sensor is the same is detected in time series with respect to the first series of exposure positions and the second series of exposure positions. do.

Description

Exposure device {EXPOSURE DEVICE}

The present invention relates to a maskless exposure apparatus that forms a pattern using an array of optical modulation elements, and more particularly, to a 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 an array of optical modulation elements such as a digital micro-mirror device (DMD) while moving the stage on which the substrate is mounted in the scanning direction. There, an optical modulation element such as a micromirror arranged in a two-dimensional image is arranged to detect the position of the projection area (exposure area) on the substrate loaded on the stage and project the pattern light according to the position. Control.

In the case of forming a fine pattern with a micrometer order, it is necessary to accurately detect the position of the substrate and project the pattern light without misalignment. However, due to the temperature change of the DMD, a difference may occur in the projection position of the pattern light, and an error may occur in the pattern formation position.

To prevent this, a plurality of optical sensors such as photodiodes are arranged next to 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 the position information serving as a reference prepared in advance (for example, see Patent Document 1).

On the other hand, in order to accurately detect the position of a movable body such as a stage, a method of detecting a reference position from changes in the amount of light of two optical sensors is known (see Patent Document 2). There, a pair of photodiodes are arranged symmetrically staggered along the scanning direction to detect the origin position of the encoder, that is, the reference position.

By moving the scale on which the slit is formed, slit light for position detection passes over the pair of photodiodes. At this time, with respect to the change in the amount of light detected, a position where the light amounts of the two photo sensors are equal to each other is detected as a reference position.

Japanese Patent Publication No. 2008-134370 Japanese Patent Publication No. 2008-134370

The size of the photodiode is larger than the pattern resolution. In addition, there are individual differences in the photosensitive characteristics of the photodiode. Therefore, even if the pattern is projected with the same light intensity, the amount of light detected is slightly different. In addition, the light projected by roughness unevenness may become unstable instantaneously, and it is difficult to accurately detect the exposure position.

Further, in the exposure apparatus, the positional difference of the substrate also occurs in the sub-scan direction along with the main scan direction. Therefore, the position of the scanning band through which the exposure area passes causes errors 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 photo sensor such as a photodiode.

The exposure apparatus of the present invention includes a light modulation element array in which a plurality of light modulation elements are arranged in a matrix, and a scanning unit for moving the exposure area by the light modulation element array relative to the object to be drawn in the main scanning direction, The first photo sensor group is inclined with respect to the main scanning direction, and the first photo sensor group is provided with a position detection unit having a second photo sensor group inclined in the reverse rotation direction with respect to the main scanning direction. Here, the reverse rotation direction refers to the opposite direction when the first photo sensor group is inclined in one rotation direction when the line along the movement direction or the scanning direction is used as a reference.

In addition, by controlling a plurality of light modulation elements, the exposure apparatus is inclined respectively in the vertical direction of the arrangement of the first and second photo sensor groups, and the width of each pattern according to the arrangement direction of the first and second photo sensor groups is , An exposure operation control unit that projects light in the first and second position detection pattern rows smaller than the photo sensor width and larger than the photo sensor interval, respectively, to the first and second photo sensor groups.

When the exposure area moves relative to each other by stage movement or the like, when one position detection pattern passes through the photo sensor, the luminance signal level increases, constants, and decreases. At the same time, in the graph of the luminance signal level of each other output from the neighboring photo sensor while light of one position detection pattern passes through the neighboring photo sensor, an intersection occurs.

In addition, the position detection unit, as the first and second position detection pattern rows pass, the exposure positions at which the level of the luminance signal output from the neighboring photo sensor is the same, the first series of exposure positions and the second series of exposure positions Is detected in time series. Accordingly, the position detection unit can calculate the two-dimensional exposure position from the detected first and second series of exposure positions. Here, the 2D exposure position can be defined based on, for example, 2D coordinates defined according to the main scanning direction and the sub-scanning direction.

The position detection unit of the present invention detects an exposure position at which the level of the luminance signal outputted from the neighboring photo sensor is the same while the light of one position detection pattern passes through the neighboring photo sensor, and the light of the position detection pattern row passes Accordingly, a series of exposure positions is detected in a time series. In addition, the exposure position here represents the relative position of the predetermined position detection pattern on the stage, 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 unaffected by roughness unevenness, individual differences in the photo sensor, and the like. For example, the exposure apparatus may be provided with a correction unit for correcting 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 represented by, for example, position coordinates determined on the drawing data. In addition, as the exposure reference position, for example, a drawing start position and the like are determined.

In addition, since the exposure position is detected in two dimensions, exposure data can be corrected not only for the drawing start position but also for the exposure position along the sub-scanning direction, so that an accurate pattern can be formed without partially overlapping the drawing area. have. For the calculation of the two-dimensional exposure position, the first and second series of exposure positions are detected by vector representation as an exposure position along the sensor arrangement direction in advance, and a typical exposure position (average value), etc. in each photo sensor group After calculating, 2D exposure position coordinates according to the main scan direction and the sub scan direction can be obtained.

The arrangement interval of the photo sensor, the pattern interval in the pattern row, and the like can be arbitrarily set. For example, the inclination placement angle α with respect to the movement direction or the main scanning direction of the first photo sensor group is in the range of 30° ≤ α ≤ 60°, and the inclination placement angle β of the second photo sensor group is -60°. ≤β≤ -30°. In particular, it is possible to arrange the first and second photo sensor groups inclined at +45° and -45°, respectively, and symmetrically with respect to the moving direction or the main scanning direction. However, the movement direction indicates a movement direction (reverse to the main scanning direction) of the object to be imaged, such as a substrate. In addition, it is possible to arrange a plurality of photo sensors at regular intervals along the scanning direction, so that the position detection pattern rows can be configured as position detection patterns lined up at regular intervals.

The shape of each pattern in the pattern row is also arbitrary, and a photo sensor may be any shape that can individually detect the passage of each position detection pattern. Specifically, when one position detection pattern passes between the photo sensors, the pattern width, inclination angle, etc. may be determined so that pattern light is projected to both of the neighboring photo sensors. For example, it is possible to project light in a pattern row in which patterns on a bar are arranged in the main scanning direction.

The number of exposure positions detected depends on the number of photo sensors and the number of patterns in the pattern row. For example, it is possible to provide two or more photo sensors to form a position detection pattern sequence with two or more position detection patterns. In this case, each position detection pattern is detected between a plurality of adjacent sensors, and at the same time, between the same adjacent sensors, a plurality of exposure positions are detected as the pattern heat passes.

With respect to the arrangement of the first and second photo sensor groups, it is possible to line up along the sub-scanning direction or within the main scanning direction within one scanning band region. When the first and second photo sensor groups are arranged in the sub-scanning direction, the exposure operation control unit may project light in the first and second position detection pattern rows simultaneously in the sub-scanning direction. Accordingly, it is possible to detect the exposure position in an adjacent region without changing the pattern. On the other hand, when the first and second photo sensor groups are arranged along the main scanning direction, the exposure operation control unit projects light in the first position detection pattern row when the exposure area passes through the first photo sensor group and exposes the exposure. When the area passes through the second photo sensor group, light in the second position detection pattern row is projected. Accordingly, a series of first and second exposure positions can be detected on the same main scanning line.

For position correction, it is possible to calculate a typical correction value such as an added/weighted average value by finding a difference between each detected exposure position and a target standard exposure position. Alternatively, it is possible to calculate a representative exposure position from a series of detected exposure positions.

The position detection unit can employ various configurations, and the luminance signal from a plurality of photo sensors may be detected by the control unit of the exposure apparatus, or the position detection unit and the position calculation unit may be provided in the previous step. In order to accurately detect the timing at which the luminance signal levels coincide, for example, the position detection unit calculates an exposure position according to the pulse signal generation unit that generates a pulse signal at a timing at which the luminance signal becomes equal, and the detected pulse signal. Equipped with a position calculator.

Various configurations of the pulse signal generator and the position detector can be configured. For example, when a plurality of exposure heads are provided and position correction is performed for each exposure head, it is possible to provide a pulse signal generator on the stage.

When detecting a series of exposure positions by a pulse signal, it is desirable to prevent the pulse signals from occurring simultaneously. Therefore, the exposure operation control unit may project light in the position detection pattern row so as to generate a series of detected pulse signals at different timings. For example, the exposure operation control unit may project light of the position detection pattern string at a predetermined pattern pitch so that a series of pulse signals are generated at approximately constant time intervals.

In the exposure method in another aspect of the present invention, the exposure area by the array of light modulating elements in which a plurality of light modulating elements are arranged in a matrix is moved relative to the object to be drawn in the main scanning direction, and the main scanning direction is The first photo sensor group inclinedly arranged and the second photo sensor group inclined in the reverse rotational direction with respect to the main scanning direction with the first photo sensor group are arranged, and the vertical direction of the arrangement of the first and second photo sensor groups Each of the first and second position detection pattern rows inclined according to the arrangement direction of the first and second photo sensor groups is smaller than the photo sensor width and larger than the photo sensor interval. Projection to the second photo sensor group, respectively, the first and second photo sensor groups, the first exposure position and the second series of exposure positions at which the level of the luminance signal output from the neighboring photo sensor is the same. It is detected in time series as the exposure position.

According to the present invention, it is possible to accurately detect the pattern formation position in the maskless exposure apparatus.

1 is a schematic perspective view of an exposure apparatus according to a first embodiment.
2 is a schematic block diagram of an exposure apparatus.
3 is a view showing a photo sensor group and a position detection pattern sequence.
4 is a view showing the width of the photo sensor and the pattern.
5 is a view showing a change in the amount of light incident to the photo sensor.
6 is a view showing changes in the amount of light of adjacent photo sensors.
7 is a diagram showing the output timing of the pulse signal in time series.
8 is a view showing a group of photo sensors and a position detection pattern in the second embodiment.
9 is a view showing a positional relationship between the position detection pattern and the photo sensor in the first photo sensor group.
10 is a view showing a positional relationship between the position detection pattern and the photo sensor in the second photo sensor group.
11 is a view showing a group of photo sensor groups and a position detection pattern in the third embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 is a schematic perspective view of an exposure apparatus according to a first embodiment. 2 is a schematic block diagram of an exposure apparatus.

The exposure apparatus (drawing apparatus) 10 is a maskless exposure apparatus which forms a pattern by irradiating light onto a substrate W coated with or attaching a photosensitive material such as photoresist, and the drawing section 13 is a base. (14).

On the base 14, a stage 12 on which the substrate W is mounted is provided to be movable along the scanning direction. The stage driving 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 shown here. The exposure head 18 is equipped with a DMD 22, an illumination optical system, and an imaging optical system (all not shown), and other exposure heads are also configured in this way. The light source 20 is composed of, for example, a discharge lamp (not shown), and is driven by the light source driver 21.

When CAD/CAM data composed of vector data or the like is input to the exposure apparatus 10, vector data is sent to the raster conversion circuit 26, and 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 an array of optical modulation elements (optical modulators) in which two micro-mirrors are arrayed in two dimensions, and each micromirror selectively switches the direction of reflection of light by changing the posture. By controlling the posture of each mirror by the DMD driving circuit 24, light according to the pattern is projected onto the surface of the substrate W through the imaging optical system.

The stage driving mechanism 15 moves the stage 12 according to the control signal from the controller 30. The position detection unit 28 is provided near the end of the stage 12 and includes a photo sensor group PD composed of a plurality of photo sensors and a pulse signal generator 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 at a constant speed along the scanning direction X. The projection area (hereinafter referred to as an exposure area) by the entire DMD 22 moves relative to 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 according to the exposure pitch.

By adjusting the control timing of each micromirror of the DMD 22 according to the relative position of the exposure area, light of a pattern to be drawn at the position of the exposure area is sequentially projected. Then, by drawing the entire substrate W with a plurality of exposure heads including the exposure head 18, a pattern is formed on the entire substrate W.

Moreover, as an exposure system, not only the continuous movement system which moves at a constant speed, but also the step & repeat which moves intermittently is possible. In addition, multiple exposures (overlap exposures) that partially overlap the projection area during exposure shots are also possible.

In the previous step of starting the exposure operation, a correction process regarding the exposure start position is performed to form the pattern at the correct position. While moving the stage 12 at a constant speed, light of the 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, detection and correction of the exposure position will be described with reference to FIGS. 3 to 7.

3 is a view showing a group of photo sensor groups and a position detection pattern sequence. 4 is a view showing the width of the photo sensor and the pattern. 5 is a view showing changes in the amount of light incident on the photo sensor.

The photo sensor group PD includes N photo sensors P1, P2, ... , PN, and are arranged in the scanning direction at equal intervals of the array pitch T. On the other hand, the position detection pattern column LP is a series of bar-shaped patterns L1, L2, L3, ... perpendicular to the scanning direction. ,LM. M patterns L1, L2, L3,... The LMs are arranged at equal intervals with the pattern pitch J.

Patterns L1, L2, L3,… The pattern width K of each LM is shorter than the photo sensor width Z. Therefore, when the pattern L1 at one leading position passes through the photosensors P1 and P2, the level of the luminance signal outputted from the photosensor P1 and the photosensor P2, that is, the light reception amount of the photosensor is shown in Fig. 5. As shown in the figure, it leads to the increase, schedule, and decrease sequentially.

As described above, as part of the pattern L1 moves on the photo sensor P1 by the movement of one pattern L1, the light amount of the photo sensor P1 increases. While the entire pattern L1 is located on the photo sensor P1, the amount of light detected by the photo sensor P1 becomes constant at the maximum amount of light. Then, as the moving front side of the pattern L1 moves beyond the photo sensor P1 and moves between the photo sensors P1 and P2, the light amount of the photo sensor P1 decreases.

Also in the photo sensor P2 located next to the photo sensor P1 with respect to the scanning direction, the light amount similarly reaches an increase, a constant, and a decrease. This change in the amount of light occurs with respect to the photo sensor P1 by being delayed by a period corresponding to the pattern pitch T. On the other hand, the width K of the pattern L1 is larger than the interval B of neighboring photosensors. Therefore, while the pattern L1 passes between the photosensors P1 and P2, a period Q occurs in which the light quantity decrease of the photo sensor P1 and the light quantity increase of the photo sensor P2 overlap (see Fig. 5).

Then, in this period Q, positions and points where the light amounts of the photo sensors P1 and P2 coincide are detected as the exposure positions. Specifically, in the pulse signal generation unit 29, a pulse signal is generated at the timing of coincidence of the light amount, and the position of the pattern L1, that is, the position of the substrate W is detected. Thereby, it is possible to detect an exposure position where an order having a photo sensor size width Z or less is required.

After the light amount coincidence point is detected when the pattern L1 passes, the light amount coincident point is also detected for the patterns L2, L3,. As a result, the M exposure position is detected between the photo sensors P1 and P2.

Moreover, not only the photo sensors P1 and P2, but also the adjacent photo sensors Pj and Pj+1 (1≤j≤N-1) detects the coincidence point as the exposure position. Therefore, N photo sensors P1, P2,... , When M patterns L1, L2, ...LM pass through the PN image, (N-1) x M times the exposure position is detected. That is, in the gap of the (N-1) photo sensor, the M exposure positions are detected each time.

6 is a view showing changes in the amount of light of adjacent photo sensors P1 and P2. 7 is a diagram showing the timing of outputting a pulse signal in time series.

The pattern pitch J of the position detection pattern row L is determined to satisfy the following equation. However, T denotes the photo sensor pitch, SA denotes the total number of pulses detected, M denotes the number of patterns, and N denotes the photo sensor number N.

J = T/M + T

SA = (N-1)M ‥‥ (1)

In this way, by setting the pattern pitch J, the output timings of a series of pulse signals output between photo sensors adjacent to each other do not overlap, and are output in time series at approximately constant intervals. In Fig. 6, a pulse signal output from the pulse pitch PS is shown.

Then, the calculation of the exposure position and the correction of the exposure start position are performed based on a series of output pulse signals. In the position calculator 27 including a pulse counter, a latch circuit, and the like, the exposure position of each pattern from a series of pulse signals sequentially output in time series based on the moving speed of the stage 12, an encoder signal, or the like, That is, the X position coordinates on the substrate are calculated.

The controller 30 sequentially calculates a difference from a preset standard exposure position for an exposure position calculated from each pulse signal. As the standard exposure position, the position coordinates of the intermediate point between (N-1) adjacent photo sensors are stored and set in advance.

After calculating the correction values for all of the detected exposure position coordinates, the average value is required. The exposure position is corrected by this average value. When the actual drawing process is performed, the exposure position is shifted by a correction value to start drawing. Here, for each of the plurality of exposure heads, the exposure position is corrected as the reference position of the substrate W.

As described above, according to the first embodiment, a position detection unit 28 in which a plurality of photo sensors P1 to PN are arranged at equal intervals along the scanning direction X is provided on the stage 12, and is equally spaced along the scanning direction X. The position detection pattern column L consisting of the phase/slit phase patterns L1 to LM is arranged at the time of scanning. Then, during the pattern heat passage, positions where the light receiving amounts of the adjacent photo sensors are the same are detected in time series as the exposure position, and the reference position is corrected based on the detected (N-1) x M exposure positions.

By projecting a pattern row on a plurality of photo sensors lined up in the scanning direction, exposure positions are detected in multiple places, and multiple exposure positions are also detected at the same point. Accordingly, it is possible to detect an accurate exposure position without being affected by variations in illuminance of pattern light, fluctuations in light quantity due to disturbance, or individual differences of photo sensors (different output characteristics of photo sensors), changes over time, and the like. It can be performed in one injection. In addition, it is possible to detect a precise exposure position without using a difficult and costly structure due to the device structure, such as miniaturization of the photo sensor size and photo sensor spacing.

Since the exposure position is detected by generating a pulse signal, the configuration of the detection section on the stage can be simplified. In particular, when a plurality of exposure heads are arranged, it is possible to generate a pulse signal at each exposure head, so that the position calculation section can be provided as a single circuit, and the configuration of the position detection section can be simplified. Moreover, since the pattern pitch or the like is set so that the pulse signals output in time series are not output simultaneously or repeatedly, it becomes possible to detect a large number of exposure positions.

The number of patterns in the pattern row, the pattern shape, and the number of photo sensors are arbitrary. If it is considered to detect the exposure position multiple times between different photo sensors, it is sufficient to form a pattern sequence composed of two or more patterns, and to form a photo sensor group with three or more photo sensors. Moreover, about a photo sensor, you may make it the structure arrange|positioned so that separation is possible.

The shape of the position detection pattern, the pattern pitch, the photo sensor pitch, the photo sensor width, and the pattern width may also be set such that, when each pattern passes, a light amount change occurs between neighboring photo sensors, and the light amount coincidence point can be extracted. That is, the pattern width may be smaller than the photo sensor width and larger than the distance between adjacent photo sensors.

Regarding the calculation of the exposure position, a representative exposure position such as an average value is first calculated from a series of detected exposure positions, and the exposure start position may be corrected based on a difference between the average value and the standard value. It is also possible to configure to detect an exposure position where the amount of light becomes the same by a configuration other than pulse signal generation.

Next, a 2nd embodiment is demonstrated using FIGS. 8-11. In the second embodiment, two-dimensional exposure positions are detected with respect to the main scanning direction (X direction) and the sub scanning direction (Y direction). About the other structure, it is substantially the same as 1st Embodiment.

8 is a diagram showing a group of photo sensors and a position detection pattern in the second embodiment. The arrangement|positioning and position detection pattern of the photo sensor group in 2nd Embodiment are demonstrated using FIG.

The position detection unit 128 is provided with a first photo sensor group 128A and a second photo sensor group 128B, and is arranged in a row along the sub-scan direction near the end of the stage 12. In the first photo sensor group 128A, a plurality of photo sensors are arranged at equal intervals along a direction inclined by +45° with respect to the movement direction (reverse to the main scanning direction).

On the other hand, in the second photo sensor group 128B, a plurality of photo sensors are arranged at equal intervals in a direction inclined by -45° with respect to the moving direction. The sensor arrangement direction of the second photo sensor group 128B is related to the movement direction/main scanning direction, and corresponds to the reverse rotation direction with the first photo sensor group 128A. In Fig. 8, the first photo sensor group 128A is inclined in the rotational direction counterclockwise from the movement direction, while the second photo sensor group 128B is inclined in the clockwise rotation direction.

In addition, the first photo sensor group 128A and the second photo sensor group 128A are disposed in the same scanning band (the region through which the exposure area passes during scanning), and in this case, parallel to the sub-scan direction, Each of the adjacent scanning bands is spaced apart.

When detecting the exposure position, the first position detection pattern row HP is projected to the first photo sensor group 128A, and the second position detection pattern IP is projected to the second photo sensor group 128B. Therefore, the 1st and 2nd position detection patterns are lined up and projected along the sub scanning direction. The first position detection pattern row HP consists of four position detection patterns H1 to H4 on the bar. In addition, the position detection patterns H1 to H4 are inclined along a direction perpendicular to the arrangement direction (+45°) of the first photo sensor group 128A, and are lined up along the movement direction/main scanning direction at equal intervals.

Similarly, the second position detection pattern column IP is composed of four position detection patterns I1 to I4 on the bar, and the position detection patterns I1 to I4 are in the arrangement direction (-45°) of the second photo sensor group 128B. They are inclined along the vertical direction, and are lined up at equal intervals along the movement direction/main scanning direction.

The first photo sensor group 128A and the second photo sensor group 128B are spaced apart in a sub-scanning direction so as to pass through the first position detection pattern row HP and the second position detection pattern IP, each of which has a different pattern, respectively. Are deployed. Each of the position detection patterns H1 to H4 and I1 to I4 has a length that intersects all the photo sensors when passing through the photo sensor groups 128A and 128B, respectively.

In addition, even when the main scanning direction shown in Fig. 8 and the moving direction of the substrate are reversed, it is possible to have a configuration in which the photo sensor groups are inclined, and projection of the first and second position detection patterns HP and IP is made accordingly. It is good to decide the pattern shape.

9 is a view showing a positional relationship between the position detection pattern and the photo sensor in the first photo sensor group. 10 is a view showing a positional relationship between the position detection pattern and the photo sensor in the second photo sensor group. 9 and 10, exposure position detection in the second embodiment will be described.

As shown in Fig. 9, when one position detection pattern H1 passes through the neighboring photo sensors PN and PN-1, the position detection pattern H1 and the photo sensors PN and PN-1 are tilted 45° with respect to the main scanning direction. Therefore, the pattern movement direction is inclined with respect to the main scanning direction. Here, the position detection pattern H1 with a small displacement is indicated by a broken line.

The relationship between the position detection pattern width K, the photo sensor width Z, and the photo sensor pitch T satisfies the same relationship as in the first embodiment. Therefore, the light quantity coincidence point is detected from the light quantity distribution detected between the photo sensors. In addition, although the position detection pattern H1 moves relative to the arrangement direction of the photo sensors PN and PN-1 in an inclined direction, the position detection pattern H1 has a sufficient length than the length of the long axis direction of the photo sensor. Therefore, the pattern passes through the entire area where the amount of light changes.

In relation to the photo sensors PN and PN-1 of the first photo sensor group 128A, when an exposure position along the photo sensor array direction is detected, the component is represented by a vector obtained by synthesizing the X component and the Y component. Since the sensor array direction is inclined +45° with respect to the movement direction, if the magnitudes of the vectors of the S1, X component, and Y component vectors of the exposure position along the array direction are represented by dX and dY, respectively, the following equation is established.

S1 = (dX + dY) / √2 ‥‥ (2)

However, the direction inclined counterclockwise with respect to the moving direction (-X direction) is set to be positive. In addition, for convenience, the said formula is shown without using a vector code (→).

Similarly, in relation to the photo sensors PM and PM-1 of the second photo sensor group 128B, when the exposure position along the photo sensor array direction is detected, the component is represented by a vector obtained by synthesizing the X component and the Y component. Lose. When the vector of the exposure position along the alignment direction represents the sizes of the vectors of the S2, X, and Y components as dX and dY, respectively, the following equations are established.

S2 = (dX-dY) / √2 ‥‥ (3)

Therefore, from the formulas (1) and (2), the X component dX and the Y component dY at the exposure position can be obtained by the following formula.

dX = (S1 + S2) / √2

dX = (S1-S2) / √2 ‥‥ (4)

As in the first embodiment, while the first position detection pattern column HP and the second position detection pattern column IP pass, when the luminance levels match from the light quantity distributions of neighboring photo sensors, the pulse signal is output in time series. do. The time interval of the detected series of pulse signals corresponds to the distance interval along the array direction (+/-45°) of the photo sensor.

Accordingly, when a series of pulse signals are detected in each of the first photo sensor group 128A and the second photo sensor group 128B, three exposure positions S1 and S2 according to the sensor arrangement direction are calculated, respectively. From the calculated series of exposure positions, representative values (average values, etc.) for S1 and S2 are calculated, and the X component and the Y component at the exposure position are calculated by the formula (4).

The calculated representative value is compared with the X component and the Y component at the reference exposure position, and correction values for the X component and the Y component are obtained. Then, based on the correction value, the exposure start position is corrected for the main scanning direction and the sub scanning direction. Alternatively, exposure data may be corrected based on the correction value to perform an exposure operation.

As described above, according to the second embodiment, the first photo sensor group 128A and the second photo sensor group 128B are respectively disposed to be inclined +45°/-45° with respect to the main scanning direction, and the inclination direction is They are facing each other. Then, for the first photo sensor group 128A, the first position detection pattern row HP inclined in the orthogonal direction of the sensor array of the first photo sensor group 128A is projected, and for the second photo sensor group 128B , The second position detection pattern column IP inclined in the orthogonal direction of the sensor array of the first photo sensor group 128A is projected.

A series of exposure positions are detected during scanning by projecting a row of position detection patterns in which two photo sensor groups are arranged in different directions and inclined in accordance with the sensor arrangement direction. Then, based on the positional information along the sensor arrangement direction from the two photo sensor groups, the exposure positions in the main scanning direction and the sub-scanning direction (X, Y coordinates) are calculated, and a correction value is obtained. Thereby, the moving distance along the sub-scanning direction of the stage is corrected, or the exposure data is corrected together with the drawing start position. In particular, by adjusting the exposure position according to the sub-scanning direction, it is possible to prevent the scanning bands from overlapping and a step in the projection area.

In addition, considering the easy calculation of the exposure position from the pulse signals of the two photo sensor groups, the sensor arrangement direction is preferably 45°, but may be other than that, for example in the range of 30° to 60° If appropriately selected, the exposure position can be detected with sufficient accuracy in practical use. Also, the inclination angles may have different sizes.

Specifically, the first photo sensor group 128A is inclined at an angle α satisfying 0°<α<90° with respect to the moving direction, while the second photo sensor group 128B is with respect to the moving direction , It should be arranged inclined at an angle β satisfying -90°<β< 0°. In addition, it is possible to arrange the inclination in this manner also in the main scanning direction.

In this case, in equation (4), a two-dimensional exposure position calculation equation can be derived using a trigonometric function indicating the sensor array 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 photo sensor group and the second photo sensor group are respectively represented by vectors, the vectors are respectively adjacent and within different upper limits. In order to be present, it is necessary to orient two arrays.

Next, a third embodiment will be described with reference to FIG. 11. In the third embodiment, the first photo sensor group and the second photo sensor group are arranged in the same scanning band, while being spaced along the main scanning direction.

11 is a view showing a group of photo sensor groups and a position detection pattern in the third embodiment.

The position detection unit 228 includes a first photo sensor group 228A and a second photo sensor group 228B, and the first photo sensor group 228A is inclined in the positive direction with respect to the main scanning direction, and the second The photo sensor group 228B is inclined in the reverse rotation direction therefrom. The 1st photo sensor group 228A and the 2nd photo sensor group 228B are main scanning directions in the same scanning band at predetermined intervals so that the exposure area passes through both photo sensor groups when moving along one scanning band. It is arranged according to.

During scanning, while the exposure area passes through the first photo sensor group 228A, the position detection pattern row HP is projected. Then, while the exposure area passes through the second photo sensor group 228B, the position detection pattern column HP is switched to the position detection pattern column IP and projected. Thereby, as in the third embodiment, a series of pulse signals is detected, and two-dimensional exposure position calculation and exposure start position correction are performed.

As for the present invention, various modifications, substitutions, and substitutions are possible without departing from the intention and scope of the present invention as defined by the appended claims. Moreover, the present invention is not intended to be limited to the processes, apparatus, manufacturing, constructs, means, methods and steps of the specific embodiments described in the specification. Those skilled in the art will recognize that, from the disclosure of the present invention, an apparatus, means, or method that substantially achieves a function, such as a function brought by the embodiments described herein, or substantially brings an equivalent action, effect. . Accordingly, it is intended that the appended claims be included within the scope of such devices, means, and methods.

This application is an application claiming priority as a basic application for a Japanese application (Japanese Patent Application No. 2013-086730, filed April 17, 2013), and the disclosure contents including the specification, drawings, and claims of the basic application are referred to as a whole. Included.

10: exposure apparatus
22: DMD (light modulation element array)
28: position detection unit
30: controller

Claims (11)

In the exposure apparatus,
An array of optical modulation elements in which a plurality of optical modulation elements are arranged in a matrix,
A scanning unit for moving the exposure area by the light modulation element array relative to the object to be imaged in a main scanning direction;
A position detection unit having a first photo sensor group inclined with respect to the main scanning direction, and a second photo sensor group inclined from the first photo sensor group in a reverse rotational direction with respect to the main scanning direction, and
By controlling the plurality of optical modulation elements, each of the first and second photo sensor groups is inclined according to the vertical direction of the array, and each pattern width according to the arrangement directions of the first and second photo sensor groups is set to the photo sensor. Exposure operation control unit for projecting light in the first and second position detection pattern rows smaller than the width and larger than the photo sensor intervals to the first and second photo sensor groups, respectively
Including,
The photo sensor width,
The size width (Z) of the photo sensor constituting the first and second photo sensor groups,
The photo sensor interval,
It is the interval (B) of the photo sensor constituting the first and second photo sensor group,
The position detection unit,
During scanning, in the first and second photo sensor groups, an exposure position at which the level of a luminance signal output from a neighboring photo sensor is the same is detected in time series as the first series of exposure positions and the second series of exposure positions. Exposure apparatus characterized in that. According to claim 1,
And the position detection unit calculates a two-dimensional exposure position from the detected first and second series of exposure positions. The method according to any one of claims 1 to 2,
The exposure apparatus, characterized in that the first and second photo sensor groups are arranged in the sub-scanning direction. The method according to any one of claims 1 to 2,
The exposure apparatus, characterized in that the first and second photo sensor groups are arranged along the main scanning direction. The method according to any one of claims 1 to 2,
The position detection unit,
A pulse signal generator for generating a pulse signal at a timing at which the luminance signals become equal, and
Position calculation unit to calculate the exposure position according to the detected pulse signal
An exposure apparatus comprising a. The method of claim 5,
The exposure apparatus, characterized in that the pulse signal generator is provided on a stage. According to claim 2,
And 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 method of claim 5,
And 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 regular time intervals. The method according to any one of claims 1 to 2,
The exposure apparatus, characterized in that the first and second photo sensor groups are integrally provided on a stage on which the object to be imaged is mounted. The method according to any one of claims 1 to 2,
The inclination arrangement angle α with respect to the movement direction or the main scanning direction of the first photo sensor group is in a range of 30° ≤ α ≤ 60°,
The exposure apparatus, characterized in that the inclination arrangement angle β with respect to the moving direction or the main scanning direction of the second photo sensor group is in the range of -60° ≤ β ≤ -30°. The exposure area by the array of light modulating elements in which a plurality of light modulating elements are arranged in a matrix is moved relative to the object to be imaged in accordance with the main scanning direction,
A first photo sensor group inclined with respect to the main scanning direction, and a second photo sensor group inclined in a reverse rotational direction with respect to the main scanning direction are disposed with respect to the first photo sensor group,
Each of the first and second photo sensor groups is inclined according to the vertical direction, and each of the pattern widths according to the first and second photo sensor group array directions is smaller than the photo sensor width and larger than the photo sensor interval. The light of the first and second position detection pattern rows is projected to the first and second photo sensor groups, respectively.
In the first and second photo sensor groups, an exposure position at which the level of a luminance signal outputted from a neighboring photo sensor is the same is detected in time series as a first series of exposure positions and a second series of exposure positions,
The photo sensor width,
The size width (Z) of the photo sensor constituting the first and second photo sensor groups,
The photo sensor interval,
The interval (B) of the photo sensor constituting the first and second photo sensor groups
Exposure method characterized in that.

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