JPS6288904A - Detecting method for displacement and rotation - Google Patents

Abstract

PURPOSE:To detect displacement and an angle with high precision by detecting the displacement perpendicular to the projection direction of a beam and the direction of rotation around an axis perpendicular to the projection direction of said beam from the combination of the outputs of plural two-dimensional photodetecting means. CONSTITUTION:A laser beam oscillated by a laser light source is split by a parallel prism 4 into two laser beams, which are converted by an axicon 5 into two ring-sectioned laser beams and incident on photodetecting element substrates 6 and 7 in a sensor housing 10. Then, the lengthwise position of a ring piece is detected by optical array sensors 6a-6d and 7a-7d arrayed in a cross shape to detect the beam positions on the substrates. Namely, when a stage 5 enters motion with the degree 5 of freedom, variation patterns of the ring positions on the substrates 6 and 7 are different as to y-directional and z-directional displacement and rotation. For the purpose, the variation patterns are detected by the optical arrays sensors simultaneously with the shaft in position, and then the extent of variation in a motion component direc tion is known.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is applicable to a high-precision positioning stage device in the phosphorography process of semiconductor manufacturing, a feed table device for precision machine tools, a high-precision stage for various measuring devices, etc. The present invention relates to a displacement/rotation detection method that can be applied to any high-precision motion stage device.

[Prior art]

In order to achieve high +S linear motion with conventional IJ near stage equipment, etc., it is necessary to combine a laser interferometer and a control machine with the Otoba static IE bearing mechanism or Tadaki bearing guide mechanism, for example. ,
A method was used in which the error was measured using a laser interferometer and the bearing was controlled by a control mechanism to correct the error. but,
In order to measure error direction components other than the direction of movement of a stage, etc. with a laser interferometer, a laser interferometer is required in the direction of the component, and a laser beam is irradiated to measure error components perpendicular to the direction of movement. Since the point moving along with the movement of the stage, the reference plane must extend to the full length of the stage, and furthermore, there is a drawback that linear movement at a high n degree is limited to the length of this reference plane.

[Purpose of the invention]

An object of the present invention is to eliminate the drawbacks of the conventional example described above, and to be able to measure all error direction components other than the stage's traveling direction using only a beam parallel to the stage's traveling direction, where the irradiation point is not affected by the stage position. At the same time, it is an object of the present invention to provide a displacement/rotation detection method that can easily identify the error direction.

〔Example〕

A first embodiment of the present invention is shown in FIGS. 1 and 4. FIG. 1st
The figure is a perspective view of the error measurement unit, where 1 is a laser oscillator which is a light source, and 4 is a laser beam! E-Parallel prism to make two parallel beams, 5 is an optical element (axico/) that converts the cross-sectional shape of the laser beam into a ring shape, 6 and 7 are light receiving element substrates, 6a to 6d and 7a to 7d are respectively The original array/su arranged on the receiving element substrates 6, 7
is a sensor housing that holds a part of the sensor. Although not shown in the figure, the housing 10 is placed on a stage, and the laser oscillator 1, parallel prism 4, and axicon 5 are placed on a fixed substrate. The stage is movable in the direction of the arrow.

In the above configuration, the laser beam oscillated by the laser light source 1 is divided into two laser beams by the parallel prism 4, and is divided into two laser beams having a curved cross section by the axicon 5. The original array sensors 6a to 6d, 7 are incident on the light receiving element substrate 6.7 in the sensor housing 101F3 and arranged in a cross pattern.
a to 7d, the respective longitudinal ring piece positions are detected, and as a result, the beam position on the substrate is detected.

Generally, if you set the stage coordinates as shown in Figure 2 I and send the stage in the direction of the arrow in the figure, that is, in the direction of Xa, the other 5
Movement of degree of freedom, i.e. y-axis, translational movement in 2-axis direction %X@1
Rotational motion around the 3' axis and the 2nd axis occurs. X in Figure 2
Axis, y-axis tz@The direction of rotation according to the length is “X+’Y”
, 'N.

FIG. 3 shows changes in the position of the ring-shaped laser source incident on the light-receiving substrate when the stage moves am+ with the five degrees of freedom in the configuration shown in FIG.

In the figure, the broken line represents the ring position before the movement, and the solid line represents the ring position after the movement. As shown in the figure, y direction a! Displacement in direction -! For each rotation in the direction, the change pattern of the sliding/gating position on the light-receiving element substrates 6 and 7 is different. Therefore, by detecting this change pattern at the same time as the original array centimeter position changes, it is possible to measure the force that has changed in which motion component direction.

Figure 4 shows a block diagram of the control system of this embodiment.In Figure 4, 11 is the stage body, 13 is the guide, 14 is the actuator, and the signals sent from the main body are converted, amplified, etc. Reference numeral B designates an error signal detection section for processing, a calculation section and a command section that process the error signal according to a certain command, and C an actuator driver section that operates the actuator 14 based on the sent signal. When the stage moves and its posture changes, a deviation from the reference laser source occurs on the optical sensor, and this signal is detected, performs appropriate arithmetic processing, issues a command to correct the posture, and sends a signal via the driver. By moving the actuator belonging to the stage, the stage can move with high precision.

Since the beam is parallel to the advancing direction of the stage, the beam will be incident on the same position on the substrates 6 and 7 no matter where the stage moves unless the above-mentioned free movement of the stage occurs. Therefore, high-precision linear motion with a long stroke of the stage is possible. In addition, since the beam direction only needs to be in one direction, the error measuring device is simple.Since the ring-shaped beam is detected by the zero axicon with an array of seven sensors arranged in a cross, the emitted laser beam can simply be used as it is on the original electric board, etc. Since the beam position can be detected with a smaller number of photoelectric elements than when the beam is incident on the beam, and the thickness of the ring that substantially coincides with the direction in which the original array sensor is arranged can be made sufficiently small, the accuracy of position detection by the original array sensor can be sufficiently increased.

Configuration of the error measuring device in the embodiment shown in Figure 1 I can think of cases where a similar pattern appears. Figure 5 ζ
The second embodiment shown here can also solve this problem.

In FIG. 5, the same members as those in FIG. 1 are given the same symbols. 2 is a beam splitter that splits Nu f in the direction of the laser source 82, and 3 is a beam pender that bends the direction of travel of the laser source.Beam splitter 2 and beam pender 3
are arranged to create two parallel laser beams. 4
° is the same parallel prism as 4, 5' is the same Aki 7 as 5, 8a to 8d, 9a to 9d are n6a to 6d, 7a respectively
~7d #This is the original array sensor, 10I is the same sensor housing as 10. Housing 10.10
' is installed on a linear stage main body 11 of a silent pressure guide type. 12 is a stage driving linear motor.

In the above configuration, the laser source oscillated by the laser light source 1 is split into two directions by the beam splitter 2I;
The transmitted light enters Akinko 15 through parallel prism 47i! ? Sensor housing 1 by converting the surface into a ring shape
The light is incident on the light receiving element substrates 6 and 7 inside the sensor 0, and is detected by the original array sensors 6a to 6d and 7a to 7d. Similarly (this reflected light is also reflected by the bender 3, the parallel prism 411, and the optical array sensors 8a to 8d, 9a)
, 9d.

The senna housings l 0 , 10' are installed on the stage main body in a vertically symmetrical manner, one direction apart from each other in the driving direction of the linear stage. FIG. 6 shows an example of changes in the rings on the substrates 6, 7, 8.9 as the five degrees of freedom other than the driving direction are achieved in this case. This image
The change patterns of the mounting/gating device on the four substrates are different depending on the direction, displacement in two directions, and rotation around XpYmZ:I'11. Therefore, by simultaneously detecting the amount of change and the change pattern, you can measure in which direction and by how much it has changed at once.
It is T-noh.

The third implementation column is shown in FIG. 7, and FIG.
Components that are the same as those in FIG. 5 are indicated by the same reference symbols. The bearing body of the direct-acting magnetic bearing guide is installed at 11 degrees. 15 is an electromagnet, and 13a is a guide.

The senna housings 10 and 10' are installed in one vertically symmetrical position on the bearing body 11', and the ring changes on the four substrates caused by the movement of the five degrees of freedom are the same as in the second embodiment. The pattern will be as shown in Figure 6.

Therefore, it is possible to simultaneously measure the amount of change in the direction of change. Since it is a direct-acting magnetic bearing, correction operations can be performed without an actuator by controlling the electromagnet current.

FIG. 8 shows a fourth embodiment. In the same figure, Figure 1,
The same symbols are used for the same members as those shown in FIGS. 5 and 7. T, 91 is a photoelectric element substrate made of a transparent member, 6aI to 6dl and 8al to 8dM! Son
Optical array sensors 7a1-7d', 9a'-9, respectively
The substrates 6' and 8' form an angle of 45° with dl.
These are the original array sensors arranged above.

The beam emitted from the laser oscillator 1 is split into two by the beam splitter 2, and the transmitted light remains unchanged, while the reflected light is made parallel to the transmitted light by the beam pender 3.
, the cross section is converted into a ring shape, and each n-substrate 7
It is incident at 9g. The part of the incident beam ring that hits the optical array sensor 7a''~7d1°9a1~9dl is blocked, but the other part is blocked by the transparent substrate 7'.
, 9' and enter rt, substrates 51 and 81, respectively.

Original arrays/substrates 6a' to 6d' on substrates 6' and 8'
, 8a' to 8dl are respectively former Aleise/su7 a
'~7d', 9a'9dl and 45@ shifted arrangement. The ring part shaded by the original array centimeter on the substrate 7'91 is the original array within the range of movement of the stage 11.6a'~6d', 8a'~8d
'No rice on top, always substrate T.

The distance between the opposing optical array sensors is sufficient so that the portion of the ring that has passed through the ring is detected. Therefore, one glue/
This makes it possible to detect the cross beam with two sets of cross bedside array sensors, and the structure becomes simpler and more compact than the first to third embodiments. In addition, in the second and third embodiments, two boards are installed in one housing shifted in the y direction or two directions, so when the rotation in the The amount of change in each of them takes on different values, and when movement in other directions is added to this, the pattern of change is complicated. In this fourth embodiment, the two substrates in one housing are not misaligned in the y direction and the two directions, ω!
Even when the ring is rotated in one direction, the amount of change in the rings on the two substrates is the same, and the pattern of change when movement in another direction is applied does not become complicated. 44th Example 1 Cool, 5 degrees of freedom other than the driving direction! Substrate 6' accompanying @,
Examples of changes in the rings on 7', 8', and 9' are shown in Figure 91.
This is shown. Although the position of the original array sensor at 8° on the substrate 6' is different, the ring change pattern is the same as in FIG.

FIG. 10 shows a fifth embodiment. In this figure, the same symbols are used for the same members as those in FIGS. 1, 5, 7, and 8.

17. 19 is a light-receiving element substrate 16 which is installed in the housing, tilting 4511 in the direction of movement of the stage 11.
．． Reference numerals 18 denote light receiving element substrates 17 and 19 at positions where the beams shown in the figure that are incident on the light receiving element substrates 17 and 19 are approximately reflected.
The housing (this is the light-receiving element board) is installed so as to form an angle of 45 degrees with the housing.

The surface of the substrate 17.19 is in close contact with the substrate and is half-mirrored.
The two are installed. The thickness of the bar 7 is made sufficiently small so that the incident light is not refracted as much as possible when transmitted. The original array sensors 17a to 17d, 19a to 19d are connected to the half mirrors on the substrates 17 and 19 (the incident beams are divided into two, and the transmitted light remains in close contact with the original array sensors 17a to 17d, 19a to 19d).
is detected. On the other hand, the reflection sources are incident on the substrates 16 and 18 tilted at 45 degrees to the half mirror, respectively, and the source array sensor 1
Light is received at 6a to 16d and 18a to 18d. In this case, the substrate 16.1 accompanies movement in 5 degrees of freedom other than the driving direction.
7, 18.19 An example of the decoration of the above ring is shown in Fig. 11. Unlike Fig. 6, the position of the ring on the substrate 17.19 does not change during rotation in the Y direction and the #2 direction.However, the pattern of change in the position of the ring on the four substrates for each movement is different. Similar to the second to fourth embodiments, it is possible to simultaneously measure the amount of change in the direction of change. Also, the pattern does not become complicated when rotating in the # direction, and the device i8 can be further miniaturized than the fourth embodiment. It is possible to measure the displacement and angle of only the area.

1st to 3rd Embodiments In the figure, the two substrates in one housing may be shifted in two directions or may be shifted in the y direction.In the fourth embodiment, the laser oscillator Viewed from the side, the distance between the optical array centimeters on the front substrate and the optical array centimeters on the back substrate is the distance between the optical array centimeters on the front substrate and the optical array centimeters on the back substrate. As long as it doesn't have rice on top, it can be in any shape. In the fifth embodiment, the substrate that receives the reflected light from the half mirror, which is inclined at 45 degrees with respect to the traveling direction, may be located on the side or bottom side of the housing. In addition, the filler substrate is formed of a total reflection mirror without a half mirror, and the alignment of the optical array centimeters of the substrate that receives the reflected light is shifted from the alignment of the original array sensor of the tilted substrate as in the fourth embodiment. It doesn't matter. Beam beam using Aki7con in all examples? The cross-sectional shape of the beam may be any shape within the scope of the present invention. For example, since the cross-sectional intensity distribution of the laser beam has a Gaussian distribution as shown in FIG. 12, the same effect as the embodiment described can be obtained by detecting a point with a certain intensity using the original array sensor. . The photoelectric elements on the substrate can be arranged in any shape other than a cross as long as the effects of the embodiments are not impaired. The laser oscillator and receiver may be installed in reverse.

〔Effect of the invention〕

According to the present invention, it is possible to detect displacements and angles with high precision at all fiLllts of the stage without being influenced by the moving distance of the stage, and at the same time, it is possible to easily identify the displacement directions and angular directions.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the error measuring device according to the first embodiment of the present invention, FIG. 2 is a coordinate diagram showing the directional relationship of the other five degrees of freedom with respect to the moving direction t of the moving body, and FIG. In the second embodiment, the light is incident on the light receiving element substrate when the movement with the five degrees of freedom is performed. FIG. 4 is a block diagram of the control system of the first embodiment, FIG. 5 is a perspective view of the second embodiment of the present invention, and FIG. FIG. 7 is a pattern diagram of the position change of the ring-shaped laser beam incident on the light receiving element substrate when the movement of the five degrees of freedom is performed in the second embodiment, and FIG. FIG. 8 is a perspective view of the fourth embodiment of the present invention, and FIG. 9 is a perspective view of the light incident on the light receiving element substrate when the movement of the five degrees of freedom is performed in the fourth embodiment. Fig. 1O is a perspective view of the fifth embodiment of the present invention, and Fig. 11 is a pattern diagram of the position change of the ring-shaped laser beam in the fifth embodiment. Pattern diagram of the position change of the ring-shaped laser beam incident on the photodetector substrate of Zeng,
FIG. 12 is an explanatory diagram of an example of the cross-sectional intensity distribution of a laser beam. T, 8°, 9I: Light receiving element substrates 6a to 6d, 7a to 7d, 8a to 8d. 8 a' to 8 d', 9 a' to 9 d'10
．． 10': Sensor housing 11: Linear stage main body 12: Linear motor 13.13': Hydrostatic bearing guide 13a: Magnetic bearing guide 14.14': Fine movement actuator 15:'Rim stones 16, 17, 18, 19: Light receiving element Substrates 16a-1
6d+17a~17d+18a~18d+19a~19
d: Original array sensor.

Claims (4)

[Claims] (1) In a beam-based displacement/rotation detection method, by combining the outputs of a plurality of two-dimensional light receiving means, at least displacement perpendicular to the beam emission direction and rotation around an axis perpendicular to the beam emission direction are detected. A displacement/rotation detection method characterized by direction detection. (2) A claim characterized in that there are three or more of the two-dimensional light receiving means, and the direction of rotation about an axis parallel to the beam is also detected by combining the outputs of the two-dimensional light receiving means. The displacement/rotation detection method according to item 1. (3) In a beam-based displacement/rotation detection method, a plurality of light-receiving element groups fixedly arranged apart from each other in the direction of travel of the light are used to detect at least displacement perpendicular to the direction of travel of the light and the direction of travel of the light. A displacement/rotation detection method that distinguishes between detection and rotation around a vertical axis. (4) A plurality of groups of light-receiving elements fixedly arranged apart from each other in a direction perpendicular to the direction of travel of the light are used to distinguish and detect rotation around the direction of travel of the light. Displacement/rotation detection method described in Section 3.