CN101135863A - drawing device - Google Patents

Abstract

A drawing device that accurately measures the position of a reference mark on an object to be drawn, such as a substrate, within a short period of time. In the drawing apparatus for drawing circuit patterns, a camera movable in the (Y) direction (main scanning direction) is arranged, and a drawing table on which a board is mounted movable in the (X) direction (sub-scanning direction) is installed. Also, the reference scale (16) is arranged along the (Y) direction and fixed to the base. Also, a light source unit for selectively emitting red light and green light is attached to the camera (11), and a dichroic mirror (15) is provided below the camera (11).

Description

drawing device

technical field

The present invention relates to a drawing device for forming a pattern such as a circuit pattern on a photo-mask (reticle) serving as an original plate, or directly on a printed object such as a printed circuit board or a silicon wafer.

Background technique

In the manufacturing process of substrates, etc., drawing processing for pattern formation is carried out on the object to be drawn that is coated with a photosensitive material such as photo-resist, and after development processing, etching or plating processing, photoresist (resist) ) stripping and other projects, the style is formed on the object to be drawn. On the substrate, pointers to be references such as marks and holes are regularly formed toward a predetermined position, and when the substrate is mounted on a drawing table (stage), by moving the drawing table and the camera, The position of the fiducial mark is detected. Also, based on the detected position, a drawing pattern is formed toward a predetermined area.

When measuring the reference mark, since it is necessary to know the correct position of the camera, for example, on the drawing table, a reference scale (scale) is installed, the drawing table is moved to a predetermined position, and the scale of the reference scale is used as a reference to measure the reference The position coordinates of the mark (Patent Document 1). In addition, based on the position coordinates of the measured reference marks, the deformation amount and alignment error of the substrate are calculated, and the drawing position is corrected.

[Patent Document 1] Japanese Patent Laid-Open No. 2004-348045

Since the reference scale is attached to the drawing table, it is necessary to move the drawing table for measuring the mark of the reference scale and the scale to the predetermined position (origin position) of the camera. Therefore, when there is an error in determining the position along the moving direction due to the driving mechanism of the drawing table, a table error occurs in the measured position coordinates. Also, every time the reference scale is used, the drawing table must be returned to the predetermined origin position, and it takes time to detect the position of the reference mark on the substrate.

Contents of the invention

The drawing device of the present invention can accurately and in a short time measure the position of the mark for measurement and the position of the hole provided on the substrate or the like, including: the object to be drawn with the reference mark for position measurement is set Equipped with a drawing table relatively movable in a first scanning direction relative to the base, and a camera mounted movably in a second scanning direction perpendicular to the first scanning direction relative to the base to measure the position of a reference mark . The reference marks here include stamps, holes, and the like, and are formed, for example, at the four corners of an object to be drawn such as a substrate. For example, the drawing table and the camera may be configured so as to be moved in the sub-scanning direction and the main-scanning direction (or vice versa).

The drawing device of the present invention includes a reference scale installed on the base and extending along the second scanning direction, and further includes: a first light source for irradiating the first illumination light for measuring the position of the reference mark, and illuminating the illumination reference scale The second light source of the second illuminating light with the wavelength range different from the first illuminating light is used, and guiding the first illuminating light to the object to be drawn and guiding its reflected light to the illuminating machine, and directing the second illuminating light Measuring optical system that guides the reference scale and its reflected light to the camera.

The optical system for measurement selects the first illumination light and the second illumination light, and guides them to the reference mark and the object to be drawn, respectively. When the camera is moved in the second scanning direction based on the position coordinates of the drawing data included in the design data, the reference scale is captured by the second illumination light emitted from the second light source while the camera is stopped at this position. The ruler becomes measurable. Also, the position of the reference mark can be directly measured by the first illumination light. The shape and configuration of the reference scale are arbitrary, and for example, a scale in which fine holes are regularly arranged at equal intervals may be used. The pitch of marks and scales may be determined according to the configuration of the drawing device, but the pitch of the driving mechanism for moving the camera must be considered, and the pitch may be determined so that the drive error does not exceed the pitch of the scales. Furthermore, the drawing device includes: a measuring device for measuring the position of the reference mark; and a correction device for correcting the drawing position based on the measured position of the reference mark.

In order to selectively distinguish the first illuminating light and the second illuminating light, it is preferable to install a spectroscopic optical system that transmits the first illuminating light and its reflected light and reflects the second illuminating light and its reflected light in the optical system for measurement. . For example, the optical system for measurement is provided with a first optical system that reflects the first and second illumination lights toward the object to be drawn, directly transmits the reflected light, and transmits the first illumination light and the reflected light. , a second optical system that reflects the second illuminating light toward the reference scale and reflects the reflected light toward the camera. Alternatively, a third optical system that reflects the first illumination light toward the object to be drawn and directly transmits the reflected light, and a second optical system that transmits the first illumination light and its reflected light and makes it incident through the reference scale is provided. A fourth optical system that reflects illumination light toward the camera. As the first and third optical systems, for example, prisms are provided. As the spectroscopic optical system, second, and fourth optical systems, for example, dichroic mirrors are provided.

As a configuration of the spectroscopic optical system, for example, a camera may be integrally attached, and the measuring optical system and the camera may move relative to the reference scale. Alternatively, the camera may be installed on the reference scale so as to extend along the reference scale, and the camera relatively moves with respect to the measuring optical system and the reference scale.

The measurement mechanism of the drawing device of the present invention includes: a camera installed movably along a second scanning direction orthogonal to the first scanning direction in which the drawing table moves relative to the base, and the measuring device is mounted on a The position of the reference mark of the object to be drawn on the drawing table; the reference scale is installed on the base and extends along the second scanning direction; the first light source irradiates the first illumination light for measuring the position of the reference mark; the second light source , illuminating the second illuminating light having a different wavelength range from the first illuminating light for illuminating the reference scale; camera, and direct the second illumination light to the reference scale and direct its reflected light to the camera.

According to the present invention, it is possible to accurately measure the position of a reference mark on a subject to be drawn such as a substrate in a short time.

Description of drawings

FIG. 1 is a perspective view schematically showing a rendering system as a present embodiment;

2 is a perspective view schematically showing a part of a measuring mechanism including a camera;

Figure 3 is a plan view of the measuring mechanism;

Fig. 4 is a block diagram of a drawing device and a drawing control unit;

5 is a plan view showing a substrate;

Figure 6 is an icon representing the position of the alignment hole of the reference scale;

Fig. 7 is the icon representing the photography screen of the alignment hole;

Fig. 8 is a plan view of the measuring mechanism in the second embodiment;

Fig. 9 is a perspective view schematically showing a part of the measuring mechanism in the third embodiment.

Symbol Description

10: Drawing device; 11: Camera;

11B: prism; 13A: first light source part;

13B: second light source part; 15: dichroic mirror;

16: Reference scale; 18: Drawing table;

20: exposure unit; 20A: light source;

20B: DMD; 21: Light source unit;

30A: drawing control unit; 32: system control circuit;

34: DMD control department; 38: Station control department;

40: stage position detection unit; SW: substrate (body to be drawn);

X: sub-scanning direction; Y: main scanning direction.

Detailed ways

Embodiments of the present invention are described below with reference to figures.

FIG. 1 is a perspective view schematically showing a rendering system of this embodiment.

The drawing device 10 of the drawing system is a device for forming a circuit pattern by irradiating light on a substrate SW coated with a photosensitive material such as photoresist on the surface, and the drawing unit 30 is connected. The drawing unit 30 includes a drawing unit 30A, a keyboard 30B, and a screen 30C, and controls the operation of the drawing device 10 while generating raster data based on CAM data (vector data) corresponding to the circuit pattern.

The drawing device 10 includes a gate-like structure 12 and a base 14 . On the base 14, a drawing table 18 is arranged, and on the drawing table 18, each substrate SW is arranged. The drawing table is carried on a pair of guide rails 19 and can move along the guide rails 19 .

An exposure unit 20 for forming a circuit pattern on the surface of the substrate SW is provided on the gate-like structure 12 fixed to the base 14 . The exposure unit 20 is mounted on a pair of guide rails 17 and is movable along the guide rails 17 . The substrate SW, for example, is a silicon wafer (silicon wafer), a film (film), a glass substrate, or a copper-clad laminate, and the blanks are applied in the prebake (prebake) process, photoresist coating, etc. ) state, it is mounted on the drawing table 18. Here, a negative photoresist is formed on the surface of the substrate.

Alignment holes AM1 to AM4 for adjusting drawing positions are formed at the four corners of the substrate SW, and a camera 11 for detecting the positions of the alignment holes is attached to the gate structure 12 . On the bottom surface of the gate-like structure 12, a guide rail (not shown) parallel to the guide rail 17 is provided, and the camera 11 can move along the guide rail. For the drawing table 18, mutually orthogonal X-Y coordinates are specified, and based on the X-Y coordinate system, the substrate SW is scanned. Here, let the main scanning direction of the moving direction of the exposure unit 20 be the Y direction, and let the sub scanning direction of the moving direction of the drawing table be the X direction.

The exposure unit 20 includes a light source, a DMD (digital micro-mirror device), and an illumination optical system and an imaging optical system (none of which are shown). The light source continuously emits light such as a semiconductor laser at a constant intensity. The radiated light is shaped into a light beam that illuminates the entire DMD by the illumination optical system, and is guided to the DMD.

DMD is a spatial light modulator in which tiny micro-mirrors are arranged in a matrix, and each micro-mirror is turned and moved by the action of an electrostatic field. Each micromirror is positioned at any one of a first posture in which the beam from the light source is reflected toward the exposure surface of the substrate SW, and a second posture in which it is reflected in a direction outside the exposure surface, and the posture is determined according to the control signal. is switched. In the DMD, the micromirrors are independently ON/OFF controlled, and the light irradiated to the entire DMD is light consisting of beams of light selectively reflected by the micromirrors. As a result, light corresponding to the circuit pattern to be formed at this location is irradiated on the exposure surface.

When the substrate SW is positioned toward the drawing start position by the movement of the drawing table 18, the exposure unit 20 moves in the Y direction. While the exposure unit 20 is moving, a pattern corresponding to the position of the irradiation spot (exposure area) of the DMD is formed, and each micromirror of the DMD is ON/OFF controlled. After the movement of the exposure region 20 along one scanning area (band) is completed, the drawing table 18 for performing drawing processing along the next band moves by a predetermined distance. Also, in order to scan the next swath, the exposure unit 20 moves at a certain speed in the opposite direction, during which the DMD is controlled corresponding to the drawing pattern.

By repeating such scanning, a circuit pattern is formed on the entire substrate. To the substrate SW on which the drawing process has been completed, development processing, etching or plating, photoresist stripping processing, etc. are applied, and a substrate on which a circuit pattern is formed is manufactured.

FIG. 2 is a perspective view schematically showing a part of a measurement mechanism including a camera, and FIG. 3 is a plan view of the measurement mechanism.

In the internal space 12A of the gate-shaped structure 12, a reference scale 16 extending in the Y direction is provided, and is attached to the gate-shaped structure 12 via a supporting member (not shown). In the reference scale 16 , fine holes (scales) are formed at regular intervals (here, intervals of about several centimeters). At the front end portion of the camera 11, a camera lens (camera lens) 11A is provided, and below the camera lens 11A, that is, on the subject side, a dichroic mirror 15 is provided. The dichroic mirror 15 is integrally attached to the camera 11 via a supporting member (not shown), and the dichroic mirror 15 moves along the Y direction, that is, along the reference scale 16 according to the movement of the camera 11 .

As shown in Figure 3, at the front end of the camera lens 11A, an optical fiber (fiber, not shown) light source unit 13 (in Figure 2, not shown) is installed along the horizontal direction, and the optical fiber transmits the light of the light source unit 13 to the camera. Inside the lens 11A. The light source unit 13 includes a first light source unit 13A and a second light source unit 13B. The first light source unit 13A emits red light L1 with a wavelength of about 660 nm, and the second light source unit emits green light L2 with a wavelength of about 525 nm.

The red light emitted from the first light source unit 13A is deflected by the prism 11B provided in the camera lens 11A, and guided to the direction of the dichroic mirror 15 along the optical axis E of the camera lens 11A. In addition, the green light emitted from the second light source unit 13A is also guided to the dichroic mirror 15 by the prism 11B.

The dichroic mirror 15 reflects light in a wavelength range (500 to 600 nm) corresponding to green, and transmits light in a long wavelength range (600 nm to) corresponding to red. Therefore, the red light L1 from the first light source unit 13A directly reaches the substrate SW, and the green light L2 from the second light source unit 13B is guided to the reference scale 16 by reflection.

The red light reaching the substrate SW is reflected, and the reflected light enters the dichroic mirror 15 . The dichroic mirror 15 directly transmits the reflected red light, and the prism 11B also directly transmits the reflected light. Thereby, the reflected light of the red light L1 enters the camera 11 . On the other hand, the green light reaching the reference scale 16 is reflected, and the reflected light enters the dichroic mirror 15 . The dichroic mirror 15 reflects the reflected green light, and the reflected light of the green light L2 passes through the prism 11B and enters the camera 11 .

FIG. 4 is a block diagram of the rendering device 10 and the rendering control unit 30A.

The rendering control unit 30A connected to the keyboard 30B includes a system control circuit 32 , a DMD control unit 34 , a stage control unit 38 , a stage position detection unit 40 , and a light source control unit 44 . The system control circuit 32 including CPU, RAM, ROM, etc. controls the overall operation of the rendering device 10 and outputs a control signal for controlling exposure time (timing) to the DMD control unit 34 . The DMD control unit 34 controls the DMD 20B according to the drawing processing program stored in the ROM in advance.

Circuit pattern data as vector data (CAM data) is input from a workstation (not shown) to mesh conversion unit 42 of drawing control unit 30A. The input vector data is converted into grid data corresponding to the grid scan, and sent to the DMD control unit 34 .

In the DMD control unit 34, the grid data is sequentially read out at a predetermined time in accordance with the relative position of the exposure area. That is, based on the read-out two-dimensional point data and the relative position information of the exposure area sent from the stage position detector 40, the control signal for ON/OFF control of the micromirror is read from the bitmap memory (bitmap memory) 43. out, towards the DMD 20B is output.

The X stage mechanism 37A includes a motor (not shown), and moves the drawing table 18 in the X direction. The Y-stage mechanism 37B also includes a motor (not shown), and moves the exposure unit 20 including the light source 20A and the DMD 20B in the Y direction. The stage control unit 38 controls the motors (not shown) of the X stage mechanism 37A and the Y stage mechanism 37B, and controls the position determination of the exposure unit 20 and the drawing stage 18.

The stage position detection unit 40 is based on an image signal (that is, a photodetection signal) transmitted from a CCD (not shown) provided in the camera 11 and a signal indicating the motor rotation position of the X stage mechanism 37A transmitted from the stage control unit 38 . The position detection signal detects the position coordinates of the alignment holes AM1 to AM4 of the substrate SW. Movement along the Y direction of the camera 11 is controlled by a camera drive mechanism 39 including a motor (not shown), and the stage control unit 38 controls the camera drive mechanism 39 .

The system control circuit 32 calculates, from the position coordinates of the alignment holes AM1 to AM4 transmitted from the stage position detection unit 40, the difference between the position coordinates of the preset drawing data and the actually measured position coordinates of the substrate SW. Alignment error. In addition, a control signal for correcting the drawing position is output to the DMD control unit 34 . In the DMD control unit 34, the storage position of the mesh data in the bitmap memory 43 is shifted by a certain amount in response to the alignment error.

The light source control unit 44 drives the light source 20A in the exposure unit 20 to emit laser light from the light source 20A. Furthermore, the system control circuit 32 drives the light source unit 21 mounted on the camera 11 to selectively turn on the first light source unit 13A and the second light source unit 13B shown in FIG. 3 . The system control circuit 32 displays an image of the alignment hole on the screen 30C based on the light detection signal transmitted from the camera 11, performs signal processing, and outputs the image signal to the screen 30C.

FIG. 5 is a plan view showing the substrate SW. FIG. 6 is a diagram showing the positions of the alignment holes of the reference scale 16 . FIG. 7 is an icon showing a photographing screen of an alignment hole. Using FIGS. 5 to 7 , the measurement procedure related to the alignment hole will be described.

The positions of the alignment holes AM1 to AM4 provided at the four corners of the substrate SW may be shifted in the X and Y directions by deformation of the substrate SW, and any one of the alignment holes AM1 to AM4 may be formed in advance. corrected position. In FIG. 5 , the position of the alignment hole AM1 is shifted in the Y direction with respect to the alignment hole AM2 .

When measuring the positions of the alignment holes AM1 - AM4 , they are measured in the X and Y directions respectively. The position coordinate data of the alignment holes AM1 to AM4 are included in the circuit pattern data as the vector data, and the movement amount along the Y direction of the camera 11 and the movement amount of the drawing table 18 are based on the position coordinate data of the alignment holes AM1 to AM4 was decided. Moreover, regarding the Y coordinate, as shown below, the positions of the alignment holes AM1 to AM4 are measured using the reference scale 16 .

When the board|substrate SW is arrange|positioned at the initial position (origin position), in order to move it, the camera 11 is moved along the predetermined distance Y direction based on the measured Y-coordinate data of an alignment hole. However, the camera 11 is at the position of Y=0 in the initial state. For example, when measuring the alignment hole AM1, the camera 11 only moves a distance Y1.

In the drive mechanism of the camera 11, a transmission error occurs, and actually, a deviation occurs between the coordinates of the position where the camera moves and the coordinates of the alignment hole in which the drawing data is included. Here, an error occurs within the range of the pitch (several centimeters) of the holes arranged on the reference scale 16 . After the camera 11 moves, the second light source unit 13B of the light source unit 21 is turned on, and the green light L2 is irradiated on the reference scale 16 . When a transmission error occurs, the position of the hole corresponding to the alignment hole to be measured of the reference scale 16 deviates from the center position of the field of view of the camera. In FIG. 6 , the hole of the reference scale 16 in the state where there is no transmission error is indicated by T1 , and the actual hole where the transmission error occurs is indicated by T2 .

Reflected light of the green light L2 is input to the CCD provided in the camera 11 , and an image signal (that is, a photodetection signal) indicating the input position of the reflected light is output from the CCD. Also, based on the detection signal, the amount of positional deviation of the holes of the reference scale 16 is detected. Afterwards, the drawing table 18 is moved only a certain amount in the X direction, and the position of the camera 11 is determined to be on top of the alignment hole. When the drawing table 18 stops, the first light source unit 13A of the light source unit 21 is turned on, the red light L1 is irradiated to the substrate SW, and the second light source unit 13B is turned off. Also, regarding the X direction, the amount of movement of the drawing table 18 is detected based on a position detection signal output from an encoder attached to a motor of the X stage drive mechanism 37A. The substrate SW is driven with the origin position of X=0 as the initial position.

When the position of the alignment hole is deviated due to deformation or the like, the alignment hole deviates from the center position of the field of view of the camera 11 . At this time, the camera 11 is moved as if the center position of the alignment hole is moved toward the center position of the field of view of the camera 11 by the operator's keyboard operation (refer to FIG. 7 ). When the camera 11 is moved, the first light source unit 13A is turned off, and the reference scale 16 is irradiated with the green light L2 again from the second light source unit 13B. Also, the amount of deviation in the position of the hole corresponding to the alignment hole of the reference scale 16 is measured.

In the system control circuit 32, the correction amount of the drawing position coordinates is detected based on the amount of positional deviation caused by the transmission error of the camera 11 and the amount of positional deviation caused by the position adjustment of the alignment hole. Also, based on the correction amount, the mesh data is corrected, and light is irradiated toward the correct drawing position of the substrate SW.

As described above, according to this embodiment, in the drawing apparatus in which the camera 11 is movable in the Y direction (main scanning direction) and the drawing table 18 on which the substrate SW is placed is movable in the X direction (sub-scanning direction), the scale of the substrate is The ruler 16 is arranged along the Y direction and fixed to the base 12 . Also, a light source unit 21 for selectively emitting red light L1 and green light L2 is attached to the camera 11 , and a dichroic mirror 15 is provided below the camera 11 .

Since the reference scale 16 does not move integrally with the drawing table 18, without driving the drawing table, the scale of the reference scale can be measured while maintaining the position of the camera with respect to the substrate, without being affected by the driving amount of the drawing table 18. The position information of the alignment hole can be accurately measured due to the influence of the error.

Next, a drawing system as a second embodiment will be described using FIG. 8 . In the second embodiment, the light source for the reference scale and the light source for alignment hole measurement are independently provided. Other configurations are the same as those of the first embodiment.

Fig. 8 is a plan view of the measuring mechanism in the second embodiment.

In the light source unit 21', only the first light source unit 13'A is provided, and behind the reference scale 16, the second light source unit 13'B is provided. When green light is emitted from the second light source unit 13'B, the green light passing through the hole of the reference scale 16 enters the dichroic mirror 15, and the green light is reflected toward the camera 11 by the dichroic mirror 15.

Next, a drawing system as a third embodiment will be described using FIG. 9 . In a third embodiment, the dichroic mirror does not move with the camera. Other configurations are the same as those of the first embodiment.

Fig. 9 is a perspective view schematically showing a part of the measuring mechanism in the third embodiment. The dichroic mirror 15' extends parallel to the reference scale, and is fixed to the gate-like structure 12 by an indicating member (not shown). The camera 11 moves along the dichroic mirror 15'.

The pitch and shape of the reference scale 16 are arbitrary, and reference scales with other configurations may be used. However, the pitch of the holes of the reference scale 16 should be determined in consideration of the transmission error of the driving mechanism of the camera, the positional deviation of the alignment holes, etc., since the holes of the specific reference scale do not fall out of the camera field of view, the holes during measurement It is enough to determine the pitch if the deviation becomes less than half of the pitch. In addition, a configuration in which the reference scale is provided in the sub-scanning direction may also be used.

An optical system other than a dichroic mirror or a prism may be used to selectively guide red light and green light to a substrate or a reference scale. In addition, instead of red light and green light, light in a wavelength range that does not react to the photosensitive material of the substrate may be used, and light in a different wavelength range may be used.

Instead of a spatial light modulator such as a DMD, a drawing device suitable for laser beam scanning using a polygon mirror or the like may be used.

Claims (7)

1. drawing apparatus, this drawing apparatus comprises:

Draw table, the drawn body that the datum mark of position measurement usefulness is set up is carried, and can relatively move along first direction of scanning for base station;

Camera can be mounted along second direction of scanning with the above-mentioned first direction of scanning quadrature movably for above-mentioned base station, measures said reference mark position;

The reference graduation chi is installed in above-mentioned base station, extends along above-mentioned second direction of scanning;

First light source, irradiation measure first illumination light that said reference mark position is used;

Secondary light source, second illumination light that irradiating illumination said reference rule is used with wavelength field different with above-mentioned first illumination light;

Measure and use optical system, above-mentioned first illuminated light guide is caused above-mentioned drawn body and its reflected light is directed to above-mentioned camera, and above-mentioned second illuminated light guide is caused the said reference rule and its reflected light is directed to above-mentioned camera;

Measuring equipment, the position of measurement said reference mark; And

Compensating device, based on the position of the said reference mark that is measured, the position is drawn in revisal.

2. drawing apparatus as claimed in claim 1, wherein above-mentioned measurement comprises with optical system:

First optical system makes above-mentioned first and second illumination light towards above-mentioned drawn body reflection, and its reflected light is directly seen through; And

Second optical system, with above-mentioned first illumination light with and reflected light see through, make above-mentioned second illumination light towards the reflection of above-mentioned reference graduation chi and its reflected light is reflected towards above-mentioned camera.

3. drawing apparatus as claimed in claim 1, wherein above-mentioned measurement comprises with optical system:

The 3rd optical system makes above-mentioned first illumination light towards above-mentioned drawn body reflection, and its reflected light is directly seen through; And

The 4th optical system, make above-mentioned first illumination light with and reflected light see through, above-mentioned second illumination light via the incident of said reference rule is reflected towards above-mentioned camera.

4. drawing apparatus as claimed in claim 1, wherein above-mentioned measurement with optical system comprise with above-mentioned first illumination light with and reflected light sees through, will above-mentioned second illumination light with and the beam-splitting optical system that reflects of reflected light.

5. drawing apparatus as claimed in claim 4, wherein above-mentioned beam-splitting optical system is mounted integratedly towards above-mentioned camera, and above-mentioned measurement can relatively be moved for the said reference rule with optical system and above-mentioned camera.

6. drawing apparatus as claimed in claim 4, wherein above-mentioned beam-splitting optical system are installed in the said reference rule as extending along the said reference rule, and above-mentioned camera can relatively move with optical system and said reference rule for above-mentioned measurement.

7. the measurement mechanism of a drawing apparatus, this measurement mechanism comprises:

Camera can measure the position of the datum mark that is arranged at the drawn body that is equipped on above-mentioned drafting table along for base station, be mounted movably with second direction of scanning of drawing the first direction of scanning quadrature that table relatively moves;

The reference graduation chi is installed in above-mentioned base station, extends along above-mentioned second direction of scanning;

First light source, irradiation measure first illumination light that said reference mark position is used;

Secondary light source, second illumination light that irradiating illumination said reference rule is used with wavelength field different with above-mentioned first illumination light; And

Measure and use optical system, above-mentioned first illuminated light guide is caused above-mentioned drawn body and its reflected light is directed to above-mentioned camera, and above-mentioned second illuminated light guide is caused the said reference rule and its reflected light is directed to above-mentioned camera.

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