JP2000346618A - Method and apparatus for precise alignment for rectangular beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position measuring apparatus capable of simply retrieving a position measuring mark and measuring an accurate position. SOLUTION: A position measuring apparatus has a coaxial type binocular two-magnification projection optical system 60 for focusing an alignment mark on a work W, first and second photographing units 71, 72 for converting a low one-magnification image and a high two-magnification image projected by the system 60 into image signals, and an image processor 80 for suitably signal processing the image signals output from the units 71, 72. First, the work W is conveyed to a stage 30, a large global mark is searched and aligned by the unit 71, and a fine mark disposed at a center of the global mark is guided to an image filed of the unit 72. Thus, the work W can be accurately measured only by moving the work W in the case of the searching and aligning, and the position of the work W can be rapidly measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a laser annealing apparatus or the like used for manufacturing a semiconductor thin film, and measures the position of an object to be measured for the purpose of aligning the object to be processed. The present invention relates to an apparatus and a method for position measurement.

[0002]

2. Description of the Related Art In a laser annealing apparatus, an amorphous semiconductor thin film formed on a glass substrate is crystallized by heating with a laser. In such a laser annealing apparatus, it may be necessary to scan a laser linear beam or spot beam on a glass substrate. At the time of such scanning, it may be necessary to detect the position of the glass substrate placed on the stage with high accuracy using a position measuring device and perform alignment.

In a conventional position measuring device, in order to accurately and quickly measure the position of a work such as a glass substrate, a positioning mark formed on the surface of the work is read by a CCD camera, and necessary image processing is performed on the read image data. To obtain a position detection signal.

[0004]

However, when performing the above-described image processing, it is necessary to insert a positioning mark on the work into the field of view of the CCD camera in advance. In particular, when high-precision positioning is required, the positioning mark becomes small, and it is extremely difficult to insert the positioning mark into the field of view of the CCD camera. Specifically, it is necessary to perform a search operation to put the positioning mark on the workpiece into the field of view, move the stage over the entire area where the positioning mark may exist, and move the stage to the position of the positioning mark in the field of view. It is necessary to confirm whether or not it exists, and the position measurement is extremely time-consuming.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a position measuring device and a method which can easily search for a mark for position measurement such as a positioning mark and perform accurate position measurement.

[0006]

In order to solve the above-mentioned problems,
The position measuring device according to the present invention has the same optical axis as the stage on which the object to be measured is mounted, and converts the image of the object to be measured on the stage to a predetermined first magnification and a second magnification larger than the first magnification. And a two-lens, two-magnification projection optical system that individually projects at different magnifications.

The position measuring device has a projection optical system having the same optical axis and individually projecting an image of the object to be measured on the stage at a first magnification and a second magnification higher than the first magnification. If the object to be measured having the first mark and the second mark smaller than the first mark at predetermined positions on the surface is placed on the stage, the image of the first mark is changed to the first mark.
By photographing at a magnification and moving the projection optical system relative to the stage by an amount corresponding to the relative position of both marks, the second mark can be arranged in the field of view of the projection optical system at the second magnification. it can. That is, the search alignment of the second mark can be performed by using the result of photographing the first mark at the first magnification, and the search alignment is performed by using the second mark arranged in the field of view of the second magnification. Precise position measurement becomes possible. Thereby, the search for the position measurement mark is simplified, and accurate position measurement is possible. When the center of the second mark coincides with the center of the first mark, an image of the first mark is photographed at the first magnification, and the photographed image of the first magnification is projected to be moved to the center of the visual field. By simply moving the optical system relatively to the stage, the second mark can be easily arranged in the field of view of the projection optical system at the second magnification. At this time, as long as the projection optical system of the two-lens two-magnification system can observe the center of the field of view at the first magnification at a higher magnification at the second magnification,
This can be achieved by using various coaxial optics.

Here, the first and second magnifications can be set appropriately according to the required measurement accuracy. From the viewpoint of quick search alignment, it is desirable to increase the field of view, that is, to reduce the first magnification. However, when performing position measurement by image processing, since the second magnification usually has a lower limit value from the viewpoint of ensuring accuracy,
If the first magnification is made smaller than necessary, the magnification difference becomes large, and it becomes difficult to perform search alignment at the first magnification and arrange the second mark in the field of view of the second magnification. Further, the sizes of the first and second marks need to be within the visual field ranges of the first and second magnifications, respectively.
In particular, the size of the first mark depends on the accuracy of placing the measurement target on the stage in order to make it easy to observe in the field of view of the first magnification. Preferably, it is small. further,
The size of the second mark needs to be set in consideration of the accuracy of the search alignment. In other words, even when the second mark is arranged at a position deviated from the center of the field of view of the second magnification due to an error in the search alignment, if the field of view of the second magnification is sufficiently larger than the second mark, the second mark is obtained. You can always catch the second mark with the magnification,
The intended precise measurement can be reliably performed.

In a preferred aspect of the position measuring device, a driving means for moving the stage relatively to the projection optical system, and a driving means for converting an image of the first magnification projected by the projection optical system into an image signal. (1) an imaging device, a second imaging device that converts an image of the second magnification projected by the projection optical system into an image signal, and driving based on an image signal of the first magnification image output from the first imaging device Control means for operating the means to guide the image at the second magnification into the field of view of the second imaging device.

In the above position measuring device, the control means includes a
The driving unit is operated based on the image signal of the first magnification image output from the imaging device to guide the image of the second magnification into the field of the second imaging device. High accuracy can be achieved.

It is preferable that the position measuring device is incorporated in a laser annealing device. The laser annealing apparatus includes a light source that generates laser light for heating an amorphous semiconductor thin film formed on a glass substrate, and an irradiation optical system that guides the laser light to the substrate in a line or spot shape. Then, the driving unit moves the stage on which the glass substrate as the measurement target is mounted relative to the projection optical system and the irradiation optical system. In this case, since the glass substrate can be precisely aligned with the irradiation optical system by the position measuring device, the process control of the laser annealing becomes more precise, and a high-quality semiconductor thin film can be obtained.

In addition, the position measuring method according to the present invention includes a step of placing an object to be measured having a predetermined first mark and a second mark smaller than the first mark at a predetermined position on the surface on a stage. A two-lens, two-magnification projection optical system having the same optical axis and capable of individually projecting an image of the measurement object on the stage at a predetermined first magnification and a second magnification larger than the first magnification. Projecting an image of one mark at a first magnification and projecting a second mark by moving the projection optical system relative to a stage based on the image of the first magnification photographed by the projection optical system; Disposing the optical system in the field of view of the second magnification of the optical system.

In the above position measuring method, the second mark is projected by moving the projection optical system relative to the stage based on the image of the first mark of the first magnification photographed by the projection optical system. Since it is arranged in the field of view of the second magnification of the system, the second mark for position measurement can be quickly contained in the field of view of the second magnification, and precise measurement using the second mark can be performed. That is, the search for the position measurement mark is simplified, and accurate position measurement is possible.

When the center of the second mark coincides with the center of the first mark, the search alignment for arranging the second mark in the field of view of the projection optical system at the second magnification becomes rapid.
Efficient position measurement becomes possible.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] Hereinafter, a position measuring apparatus and method according to a first embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a diagram conceptually illustrating the structure of a laser annealing device incorporating the position measuring device of the embodiment. The laser annealing apparatus is a work W which is a glass plate.
A laser light source 10 for generating an excimer laser or other laser light AL for heating a semiconductor thin film of amorphous Si or the like formed thereon, and forming the laser light AL in a line or spot shape on the work W at a predetermined illuminance. Irradiating optical system 20, a stage 30 on which a work W is placed and which can be smoothly moved in the XY plane and rotatable around the Z axis, and a stage 30 on which the work W is placed
And a stage driving device 40, which is a driving means for moving the laser beam by a required amount with respect to the irradiation optical system 20 and the like. The irradiation optical system 20 includes, for example, a homogenizer 20a that makes the incident laser beam AL a uniform distribution, and a homogenizer 20a.
And a projection lens 20c for reducing and projecting the slit image of the mask 20b onto the workpiece W.

Further, this laser annealing apparatus is a position measuring device, in addition to the stage 30 and the stage driving device 40, a moving amount measuring device 50 for detecting the moving amount of the stage 30 as optical information or electric information. A projection optical system 60 of a two-lens, two-magnification type that forms an alignment mark on the work W as a pair of images, and a relatively low magnification first magnification image projected by the projection optical system 60. A first imaging device 71 for converting the image into a signal, a second imaging device 72 for converting an image of the second magnification having a relatively high magnification projected by the projection optical system 60 into an image signal, and a first and a second imaging device.
An image processing device 80 that performs appropriate signal processing on image signals output from the imaging devices 71 and 72 and an illumination lamp 65 that supplies illumination light to the projection optical system 60 for illuminating the surface of the work W are provided. The main controller 85 controls not only the position measuring device but also the operation of each part of the laser annealing device.

The projection optical system 60 will be described in more detail. The projection optical system 60 is a coaxial type two-lens two-magnification optical system as described above, and converts the image of the work W on the stage 30 to a first imaging device 71 at a relatively low first magnification.
First lens systems 61a and 61b projecting upward, second lens systems 62a and 62b projecting the first lens systems 61a and 61b onto the second imaging device 72 at a relatively high second magnification, and image light IL from the work W
A half mirror 63 that divides the laser light into first lens systems 61a and 61b and second lens systems 62a and 62b, and an illumination lamp 6 that generates illumination light having a wavelength different from that of the laser light source 10.
Illumination light from the second imaging device 7 via the cable 66
And an epi-illumination system 67 for guiding the light onto the second optical axis.

Here, first lens systems 61a and 61b,
The second lens systems 62a and 62b are coaxial optical systems sharing an optical axis. That is, the first lens systems 61a, 61
The image light IL emitted from the work W along the optical axis 1b is
When the light is reflected by the half mirror 63, the first imaging device 7
1 and enters the center of the
Is transmitted to the center of the field of view of the second imaging device 72 along the optical axes of the second lens systems 62a and 62b. The epi-illumination system 67 is also coaxially arranged with the second lens systems 62a and 62b, and the first and second imaging devices 71 and 7
A region on the workpiece W corresponding to the second field is uniformly illuminated.

The first imaging device 71 is composed of a CCD which is a solid-state imaging device.
The D camera 73 is configured. The CCD camera 73 is fixed to one end of a lens barrel 75 that houses the lens 61a. On the other hand, the second imaging device 72 also includes a CCD element,
A CCD camera 74 is configured together with the lens 62b. The CCD camera 74 includes a lens barrel 7 containing a lens 61a.
6 is fixed to one end. The other ends of both barrels 76 are fixed to a case that houses half mirror 63.

FIG. 2 is a diagram showing an example of the arrangement of alignment marks formed on the surface of the work W placed on the stage 30. Alignment marks M1, M2 shown
Are double patterns in which light and dark binary cross patterns are combined in magnitude.

The first alignment mark M1 indicates that the workpiece W
Are formed at one of the four corners of the work W, and the second alignment mark M2 is formed at the other of the four corners of the work W. Thus, the first and second alignment marks M
1. The reason why M2 is formed at two places on the work W is to detect not only the position of the work W but also the rotation of the work W. That is, the first and second alignment marks M1,
By measuring the position of M2, the coordinates of the two reference points on the work W can be known, so that the alignment of moving the work W to an appropriate position after correcting the posture of the work W becomes possible.

FIG. 3 is an enlarged view for explaining the shape of the alignment mark of FIG. FIG. 3A shows an example of an alignment mark when the background is dark, and FIG.
(B) shows another example of the alignment mark when the background is bright. In the case of the alignment mark shown in FIG. 3A, a white mark global mark M11 which is the first mark.
The black mark fine mark M12, which is the second mark smaller in size than the global mark M11, is arranged so that the center of symmetry coincides with the center of the mark. In the case of the alignment mark shown in FIG. 3B, the center of symmetry coincides with the center of the black mark global mark M11 'as the first mark, and the white mark as the second mark smaller in size than the global mark M11'. Are arranged.

FIG. 4 is a view for explaining position detection using the alignment marks shown in FIG. FIG. 4 (a)
3A shows an image of the alignment mark of FIG. 3A, and FIG. 4B is a graph showing the integrated light amount in the Y direction of the alignment mark of FIG. 3A as a function of the X coordinate. This integrated light amount is obtained by performing image processing on the image of the alignment mark by the image processing device 80.
That is, the image of the alignment mark is
However, since the output of the image signal of the first imaging device 71 is data on a pixel basis, the image processing device 80 adds all these image signals in the Y direction for each X coordinate, thereby A distribution as shown in FIG. 4 (b) is obtained. As is clear from the graph, a peak appears at a portion corresponding to the white cross vertical bar of the global mark M11. When this distribution is processed with an appropriate threshold value TH, a pair of X coordinates (X1, X1) corresponding to a pair of edges extending in the Y direction of the global mark M11.
X2) is obtained, and by averaging the pair of X coordinates (X1, X2), the X coordinate of the center of the global mark M11 can be determined.

In the above description, the X coordinate of the global mark M11 is determined, but the same applies to the Y coordinate of the global mark M11. That is, the image processing device 8
At 0, by adding the image signal from the first imaging device 71 in the X direction for each Y coordinate, a distribution similar to that shown in FIG. 4B is obtained, and the center of the global mark M11 is obtained by the same procedure as described above. The Y coordinate can be determined.

When the coordinates of the global mark M11 are determined as described above, the fine mark M12 arranged at the center of the global mark M11 can be moved almost exactly to the center of the field of view of the second image pickup device 72. .

If the fine mark M12 can be positioned substantially at the center of the field of view of the second image pickup device 72, the above-described position detection method applied to the global mark M11 can be applied to the position detection of the fine mark M12. Therefore, the XY coordinates of the fine mark M12 can be accurately determined. In this case, the second imaging device 72 has a large enlargement ratio and detects an image of the work W in finer pixel units, so that more precise position detection is possible.

Hereinafter, the operation of the laser annealing apparatus of the present embodiment will be described. First, the work W is transported and placed on the stage 30 of the laser annealing apparatus. Next, the work W on the stage 30 is aligned with the irradiation optical system 20 that guides the annealing laser beam AL. next,
While appropriately moving the stage 30 with respect to the irradiation optical system 20, the laser light AL from the laser light source 10 is incident on the workpiece W in a line shape or a spot shape. On the work W, a thin film of an amorphous semiconductor such as amorphous Si is formed, and the semiconductor is annealed and recrystallized by irradiation with the laser beam AL to provide a semiconductor thin film having excellent electrical characteristics. it can.

When aligning the work W on the stage 30 with respect to the irradiation optical system 20, a position measuring device is used. That is, the stage 30 is appropriately moved by the stage driving device 40, and the first alignment mark M1, that is, the global mark M11 and the fine mark M12 are guided into the field of the first imaging device 71 (step S1). Since the position of the work W on the stage 30 is within a certain range of the conveyance accuracy (in the embodiment, 0.5 to 1 mm), the stage 30 is appropriately moved with respect to the projection optical system 60, and the first lens The first alignment mark M1 can be moved within the field of view of the systems 61a and 61b, that is, within the field of view of the first imaging device 71 (5 mm size in the embodiment). For example, if the position of the first alignment mark M1 on the work W is previously input and stored as data, the stage 30 is appropriately moved based on the position data of the first alignment mark M1, and the first imaging device 71
It is assured that the first alignment mark M1 is almost certainly inserted into the field of view.

Next, among the first alignment marks M1, first, for the global mark M11, the image processing device 80
In, the position is measured by processing the image signal from the first imaging device 71 with a low magnification by the method shown in FIG. 4 (step S2). Note that there is a precise correspondence between the pixels of the first imaging device 71 and the distance on the stage 30, and the center of the first imaging device 71, ie, the first lens system 6
The XY components of the distance from the optical axes 1a and 61b to the center of the global mark M11 can be accurately determined.

Next, while measuring the moving amount by the moving amount measuring device 50, the stage driving device 40 is driven to
0 in the XY plane, the first lens system 6
The center of the global mark M11 is made to coincide with the optical axes of 1a and 61b (step S3). In addition, the movement amount measuring device 50
Corresponds to the distance obtained in step S2. At this time, the positioning accuracy by the global mark M11 is about 10 μm in the embodiment. By the search alignment as described above, the fine mark M12 arranged at the center of the global mark M11 can be surely moved into the field of view (0.5 mm size in the embodiment) of the high-magnification second imaging device 72. it can.

Next, the position of the fine mark M12 is measured by processing the image signal from the second image pickup device 72 in the image processing device 80 in the same manner as shown in FIG. 4 (step S4). Note that there is a precise correspondence between the pixel of the second imaging device 72 and the distance on the stage 30, and the center of the second imaging device 72, ie, the second
From the optical axis of the lens systems 62a and 62b, the fine mark M12
The distance to the center of can be determined accurately. The position measurement accuracy of the fine mark M12 is about 1 μm in the embodiment.

Here, the projection optical system 60 for measuring the position of the fine mark M12 has a predetermined positional relationship with the irradiation optical system 20 for laser annealing, and this positional relationship is measured in advance or Has been adjusted. Therefore, the distance from the optical axis of the second lens system 62a, 62b to the center of the fine mark M12 is converted to the distance from the laser annealing irradiation optical system 20 to the center of the fine mark M12 based on the above positional relationship. (Step S5). Thus, the first alignment mark M
1 enables precise coordinate determination.

The above measurement (steps S1 to S5) is similarly performed for the second alignment mark M2, and precise coordinates can be determined for the second alignment mark M2 (step S6). In the embodiment, the second
One pixel of the imaging device 72 was set to 1 μm, and position detection was performed with an accuracy of about 1 μm.

Next, the work W is aligned with the irradiation optical system 20 based on the precise coordinate measurement results of the first and second alignment marks M1 and M2 obtained in steps S5 and S6 (step S7). Specifically, the first and second alignment marks M based on the irradiation optical system 20
1. The position and rotation of the work W are obtained based on the coordinate measurement values for the fine mark of M2, and the work W is arranged at the necessary position at the start of laser annealing based on the result and the required rotation posture.

Next, a laser beam AL such as a laser spot or a laser line irradiated from the irradiation optical system 20 is scanned on the work W by using the stage driving device 40 and the movement amount measuring device 50. Is recrystallized to sequentially form a polycrystalline thin film on the work W. At this time, by scanning the stage 30 in the X direction or the Y direction by the stage driving device 40 while observing the movement amount with the movement amount measuring device 50, the scanning with the laser beam AL becomes possible. The scanning of the laser beam AL can also be performed by giving the irradiation optical system 20 a scanning function, for example, by moving a mask 20b inside the irradiation optical system 20.

According to the position measuring method of the first embodiment described above, after the work W is conveyed and mounted on the stage 30, high precision can be obtained only by moving the work W by search alignment using the global mark M11. The position can be measured, and the position of the workpiece W can be quickly measured.
Further, since the outlines of the global mark M11 and the fine mark M12 are similar, the image measurement algorithm for measuring the marks M11 and M12 can be made substantially common, so that the arithmetic processing and the like can be simplified. .

[Second Embodiment] Hereinafter, a second embodiment according to the present invention will be described.
The position measuring device and method according to the embodiment will be specifically described with reference to the drawings. In the second embodiment, the first
This is a modification of the embodiment, and the structure of the position measuring device itself is the same as the device of the first embodiment, but the shape and arrangement of the alignment marks formed on the surface of the workpiece are different from those of the device of the first embodiment. I have. For this reason, the position measurement algorithm is slightly different from that in the first embodiment.

FIG. 5 is a perspective view for explaining the arrangement of the alignment marks formed on the surface of the work W placed on the stage 30 (see FIG. 1).

First and second global marks M111, M2
Reference numerals 11 are formed at any of the four corners of the work W. The two global marks M111 and M211 have the same coordinates on the work X axis and different coordinates on the work Y axis. On the other hand, the first and second fine marks M112,
M212 are arranged near the processing area PA on the work W, respectively. The fine marks M112 and M212 have the same coordinates on the work X axis and different coordinates on the work Y axis. The processing area PA is an area where a slit image or the like of the mask 20b is to be projected by the projection lens 20c, and is arranged at an appropriate interval on the work W (only two are illustrated in the drawing).

First and second global marks M111, M2
By the position measurement of 11, the coordinates of the two reference points around the work W can be known, and after correcting the posture of the work W, each of the first and second fine marks M112 and M212 is moved to the second position on the high magnification side. 2. Search alignment (global alignment) in the field of view of the two imaging devices 72 becomes possible. On the other hand, by measuring the positions of the first and second fine marks M112 and M212, the precise coordinates of the two reference points around the processing area PA corresponding thereto can be determined. Processing image P
A can be precisely projected on A.

FIG. 6 is an enlarged view for explaining the shape of the alignment mark of FIG. FIG. 6A shows an example of alignment marks M111 and M112 with a white cross on a dark background, and FIG. 6B shows an example of alignment marks M111 'and M112' with a black cross on a light background. Show. In the position detection using the first global mark M111 as shown in FIG. 6A, the integrated light amount in the X direction and the Y direction of the alignment mark is calculated by the image processing device 80, thereby obtaining the position shown in FIG. With such a distribution, the XY coordinates of the center of the first global mark M111 can be determined. In the same manner, the XY coordinates of the center of the second global mark M112 can be determined. Further, although the first and second fine marks M112 and M212 have different sizes, the XY coordinates can be determined by performing similar processing in the image processing device 80.

Hereinafter, the alignment operation and the like of the laser annealing apparatus of this embodiment will be described. First, the stage 30 is appropriately moved by the stage driving device 40,
The first global mark M111 is guided into the field of view of the first imaging device 71. Then, the position (X-Y coordinate) of the first global mark M111 is measured by processing the image signal of the low magnification from the first imaging device 71 in the image processing device 80. The above measurement is similarly performed for the second global mark M112, and the position is also measured for the second global mark M112.

Next, the main controller 85 controls the first and second
Based on the measurement positions (coordinate values) of the global marks M111 and M112, the approximate positional deviation amounts (ΔXg, ΔYg, Δθg) from the target values when the work W is mounted on the stage 30
Is calculated.

Next, while measuring the movement amount by the movement amount measuring device 50, the stage driving device 40 is driven to
0 is translated or rotated in the XY plane to guide the first fine mark M112 into the field of view of the second imaging device 72. At this time, the coordinate values (ΔXg, ΔYg, ΔYg,
Since the correction is performed based on Δθg) and the coordinate value is converted into an actual coordinate value, the first fine mark M112 always enters the field of view of the second imaging device 72 with high magnification. Then, the image processing device 80 processes the image signal from the second imaging device 72 to measure the precise position of the first fine mark M112. The above measurement is similarly performed for the second fine mark M212, and the second fine mark M2
Measure the precise position for 12 as well.

Next, the first and second samples obtained as described above are obtained.
Based on the precise coordinate measurement results of the fine marks M112 and M212, the position and rotation of the work W, that is, the amount of positional deviation (ΔXf, ΔYf, Δθf) are obtained. The work W is precisely arranged with a proper rotation posture. The XY of the work W
The reference position (processing start position) on the axis is, for example, the mask 20.
b is aligned with the corresponding reference position on the XY axes,
The rotation angle θ of the work W corresponds to the processing direction, but is aligned with the rotation angle θ of the mask 20b.

Next, while scanning the linear laser light AL emitted from the irradiation optical system 20 within the processing area PA on the work W using the stage driving device 40 and the movement amount measuring device 50, the work W The amorphous thin film in the upper processing area PA is recrystallized, and a polycrystalline thin film is sequentially formed on the work W. At this time, while observing the movement amount with the movement amount measuring device 50, the stage driving device 40
Is moved in the X direction or the Y direction so that the laser beam AL
Can be scanned. Further, when the scanning of the laser beam AL in one processing area PA is completed, the stage 30 is moved stepwise to scan the laser beam AL in the next processing area PA. When moving from one processing area PA to the next processing area PA, the precision of the first and second fine marks M112 and M212 arranged near such a next processing area PA is improved in order to increase the alignment accuracy. It is also possible to correct the positional deviation amount (ΔXf, ΔYf, Δθf) by performing a proper coordinate measurement.

According to the position measurement method of the second embodiment described above, the large global marks M111 and M211 formed at two locations are image-measured using the low-magnification CCD camera 73, and the work W is loaded. Displacement amount at the time (△ Xg,
ΔYg, Δθg), the position of the high-magnification mark is corrected, and small fine marks M112 and M212 formed at two locations are image-measured using the high-magnification CCD camera 74 to determine the minute position. Since the processing start point position and the processing direction are corrected by calculating the deviation amounts (ΔXf, ΔYf, Δθf), alignment can be performed more accurately and at high speed.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment. Global mark M11, M111 and fine mark M1
2. The contour of M112 is not limited to a cross, and may be, for example, a pair of large and small rings, and the size ratio between the two may be appropriately determined according to the target position measurement accuracy, the size of the field of view, and the like. Can be adjusted. Furthermore, the global mark M1
The contours of M1 and M111 and the fine marks M12 and M112 are not limited to similar shapes.
A variety of mark shapes can be combined, such as a ring zone for 11, 111 and a cross for fine marks M12, M112. Further, the contrast of the global marks M11, M111 and the fine marks M12, M112 can be appropriately set according to required accuracy, workability of the work W, surface color, and the like.

The coaxial type two-lens, two-magnification projection optical system 60 is not limited to the structure shown in FIG. 1, but projects a low-magnification image onto the first image pickup device 71 to produce a low-magnification image. Various optical systems can be used as long as the centers are substantially the same and can project a high-magnification image onto the second imaging device 72.

In addition, the above-mentioned position measuring device uses the laser light A
L is used to anneal the semiconductor layer on the work W. However, if the structures of the laser light source 10 and the irradiation optical system 20 are appropriately changed, not only the annealing of the semiconductor material but also the modification and cutting of various materials can be performed. , A pulse laser processing apparatus or the like that enables welding and the like.

[0052]

As is apparent from the above description, according to the position measuring apparatus of the present invention, the image of the object to be measured on the stage has the same optical axis and the second magnification of the first magnification and the high magnification. Since it has a projection optical system that projects individually with the magnification,
If an object to be measured having a predetermined first mark and a second mark smaller than the first mark attached to a predetermined position on the surface is placed on a stage, an image of the first mark is photographed at a first magnification, By moving the projection optical system relative to the stage by an amount corresponding to the relative position of both marks, the second
The mark can be located in the field of view of the projection optical system at the second magnification. That is, the search alignment of the second mark can be performed by using the result of photographing the first mark at the first magnification, and the search alignment is performed by using the second mark arranged in the field of view of the second magnification. Precise position measurement becomes possible. Thereby, the search for the position measurement mark is simplified, and accurate position measurement is possible.

According to the position measuring method of the present invention, the projection optical system is moved relative to the stage based on the image of the first mark of the first magnification photographed by the projection optical system. Since the second mark is disposed in the field of view of the second magnification of the projection optical system, precise measurement can be performed using the second mark for position measurement. That is, the search for the position measurement mark is simplified, and accurate position measurement is possible.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a laser annealing apparatus incorporating a position measuring device according to a first embodiment.

FIG. 2 is a diagram illustrating a position measurement mark on a work placed on a stage of the apparatus of FIG.

3A is a diagram illustrating a detailed shape of a position measurement mark in FIG. 2, and FIG. 3B is a modified example thereof.

4A and 4B are diagrams illustrating a position measurement algorithm of the position measurement mark in FIG. 3; FIG. 4A is a graph corresponding to the image in FIG. 3A, and FIG. It is.

FIG. 5 is a perspective view illustrating an arrangement of position measurement marks according to a second embodiment.

6A is a diagram illustrating a detailed shape of the position measurement mark in FIG. 5, and FIG. 6B is a modified example thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Laser light source 20 Irradiation optical system 30 Stage 40 Stage driving device 50 Moving amount measuring device 60 Projection optical system 61a, 61b First lens system 62a, 62b Second lens system 65 Illumination lamp 71, 72 First and second imaging device 73, 74 Camera 80 Image processing device 85 Main control device IL Image light M1, M2 First and second alignment marks

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA03 AA17 AA20 BB28 CC17 DD06 FF01 FF04 FF67 GG04 HH04 HH05 JJ03 JJ05 JJ26 LL30 LL63 MM03 MM16 PP12 QQ27 QQ29 QQ31 QQ42 TT02 UU07 BA12CA05 BC05CAB HA57 JA04 JA38 KA06 MA27 MA30 5F052 AA02 BA18 BB07

Claims (4)

[Claims] A stage on which the object to be measured is mounted; and an image of the object to be measured on the stage having the same optical axis and a predetermined first magnification and a second magnification larger than the first magnification. A position measuring device comprising: a two-lens, two-magnification projection optical system that individually projects. A driving unit configured to move the stage relative to the projection optical system; a first imaging device configured to convert the first magnification image projected by the projection optical system into an image signal; A second imaging device that converts the second magnification image projected by the projection optical system into an image signal, and the driving based on the image signal of the first magnification image output from the first imaging device. 2. The position measuring apparatus according to claim 1, further comprising control means for operating the means to guide the image at the second magnification into the field of view of the second imaging device. 3. A step of placing on a stage an object to be measured on which a predetermined first mark and a second mark smaller than the first mark are attached at predetermined positions on the surface; An image of the object to be measured on the stage is set at a predetermined first magnification and a second magnification larger than the first magnification.
A step of photographing the image of the first mark at a first magnification by a two-lens two-magnification projection optical system capable of individually projecting a magnification and a magnification, based on the image of the first magnification photographed by the projection optical system; Disposing the second mark in the field of view of the projection optical system at the second magnification by moving the projection optical system relative to the stage. 4. The position measuring method according to claim 3, wherein the center of the second mark coincides with the center of the first mark.