JPS59171809A - Positioning mechanism - Google Patents

Abstract

PURPOSE:To enable stable positioning operations by supporting a sample table rotatably around two axes crossing at right angles to each other, and by detecting the direction of regular reflection of a laser beam on the surface of a sample, which is applied thereto from the reference direction. CONSTITUTION:A laser beam 17 is applied obliquely from above to the central point on the surface of a sample 1 by a laser oscillator 16, and a light regularly reflected on the surface of the sample is received by a one-dimensional position sensor 18. The reception position signal output thereof is inputted to a control device 8 through an amplifier 19 and an analog operator 20. The control device 8 drives a pulse motor 15-1 by an amount corresponding to the modification of a height, thus moving a height adjusting mechanism 15 by the amount.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a positioning mechanism, and more particularly to a positioning mechanism for positioning a thin plate-like sample so that it has an inclination of a predetermined angle with respect to a reference direction.

[Prior art]

For example, the flatness of a flat sample surface can be measured with high accuracy (error 0.0
In a flatness measuring device for measuring K (approximately 1 μm), the sample surface is set in advance in the reference direction, and its
It is also necessary to match the Z position to the reference position.

The most problematic of these is setting the surface to be measured in the feeding direction, and conventionally the following mechanism has been used.

Fig. 1 shows an outline of a conventional spring-balance type perpendicularity adjustment mechanism for positioning a plane perpendicular to the optical axis, and (a) is a partially cutaway perspective view. ,
(b) is a side view showing main parts.

This mechanism is supported at one point by a steel ball 1', and
Table 3 whose periphery is connected at several points by springs 2'
By placing the sample on the XY table 5' and moving the position of the steel ball 1' on the XY table 5', the inclination of the table 3' surface is corrected by balancing the tension between the support point and the spring 2'. It is.

However, with this mechanism, there are problems in that the center of rotation of the above-mentioned tilt correction operation (tilt) is not constant, so the vertical position changes when adjusting the verticality, and the fixing force of the table is weak, causing external vibrations and moving the sample on the table. It is easily affected by changes in the center of gravity, and there are problems such as a lack of stability.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide a positioning mechanism that solves the above-mentioned problems in conventional positioning mechanisms and allows stable positioning operations.

[Summary of the invention]

The gist of the present invention is to provide a mechanism for positioning a flat sample placed on a sample stand at a predetermined angle with respect to a reference direction. means for detecting the inclination of the sample surface by detecting the direction of specularly reflected light on the sample surface of a laser beam irradiated onto the sample surface from the reference direction; and means for adjusting the inclination of the sample stage based on the output of the detection means.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

The following description will be made by taking as an example a comprehensive sample positioning mechanism that is an embodiment of the present invention, which is a sample table tilt adjustment mechanism combined with an XY-direction positioning mechanism and a Z-direction positioning mechanism.

Note that in this specification, the XY directions refer to mutually orthogonal directions defined within a plane including the sample surface, and the Z direction refers to a direction perpendicular to the plane.

An outline of the positioning mechanism of this embodiment will be described below.

(1) Multiple small samples (for example, several n squares) are lined up in a straight line and loaded onto an adapter (a type of pallet), and the adapter can be handled as a unit, and the individual samples can be handled in detail. I do.

(2) Positioning in the X and Y directions is performed by pressing the adapter against a linear guide block whose positioning accuracy has been ensured in advance and fixing the position. Unloading is performed using a common push rod.

(3) Positioning in the Z direction is adjusted by converting the amount of deviation from a reference value detected using a laser beam and a position sensor into the number of pulses sent to a pulse motor, and using a ball screw, taper slide, etc.

(4) Tilt adjustment is performed by converting the deviation from a reference value detected using a laser beam and a position sensor into the number of pulses sent to a pulse motor, and adjusting from two directions via a ball screw, slide guide, etc.

Each item will be explained in detail below.

(1) Loading/unloading and XY direction positioning mechanism FIG. 2(a) shows details of an adapter for setting a plurality of samples at once. Sample 1 is mounted on adapter 2 and leaf springs 2-1. Its X individually by pin 2-2 and straight block 2-3.

The Y direction position is fixed. That is, the position in the X direction is regulated to an equal pitch by contacting the linear block 2-3, and the position in the Y direction is regulated to the reference line A by the pin 2-2.
This state is maintained by the leaf spring 2-1. Pins 2-4 indicated by broken lines are provided on the back side of the adapter 2, and will be described later.

Figure 2(b) shows the adapter 2 holding the sample as described above.
This figure shows the main part of the mechanism for loading and unloading the data onto and from the measurement table 9. The adapter 2 placed on the right side of the measurement table 9 is sent onto the measurement table 9 by a linear feed mechanism 1 (hereinafter simply referred to as "feed mechanism") 4. The feeding mechanism 4 includes a pulse motor 4-1. Rack and binion 4-2° feed guide 4-3. Sample feeding rod 4-
4 and a feed position detection switch group 4-5. The main feed mechanism is the feed position detection switch group 4-5.
Adapter 2 is moved at a predetermined pitch based on the output of
It has a function to stop. Then, with each sample 1 at the center position of the measurement table 9, necessary measurement operations are performed, and when this is completed, the next sample is sent to the center position of the measurement table 9. Repeat this process and when all the samples have been measured, operate the feed mechanism 4 again.
The adapter 2 is sent to the position of the adapter carrying belt 5 provided on the left side of the measurement table 9. The carry-out belt 5 is driven by a mokuro to carry out the adapter 2. These controls are performed by a control device 8 equipped with a microcomputer.

Next, the X of the adapter 2 on the measurement table 9,
Y-direction alignment will be explained. FIG. 2(C) is a diagram showing details of positioning of the adapter 2 on the measurement table 9 in the X and Y directions.

The adapter 2 has the pins 2 for each arrangement pitch of the sample 1.
-4 is provided. An adapter X and Y direction positioning mechanism 3 are provided on the measurement table 9. The positioning mechanism 3 is rotatable about a fulcrum 3-IA and is pivotable about a presser lever 3-2. Ratchet 3-3. is biased in direction 3-0 by spring 3-5. It is composed of a reference slide surface 3-8 and a leaf spring 3-7.

The adapter 2 fed from the right side of the figure by the feeding mechanism 4 is moved by the above-mentioned ratchet) 3-3. Press lever ~ 3-2
are moved against the springs 3-5 and 3-4, respectively, and stopped at the position shown in the figure. When the feed mechanism is moved slightly backward, the holding lever 3-2 pushes the pin 2-4 to the right in the figure by the spring 3-4, and the ratchet 3-2
3 is restrained by the stopper 3-6, the adapter 2 stops at a position regulated by the ratchet 3-3 and is aligned with a predetermined reference position in the X direction.

In addition, regarding the Y direction, the adapter 2 is connected to the plate spring 3-7.
A fixed position can be obtained by pressing against the reference slide surface 3-8. In addition, by feeding the same pitch in the X direction and stopping in the same manner as above, it is possible to align the position of each sample 1 on the adapter 2 in the X and Y directions with an accuracy of about ±10μm. can. Since the positioning mechanism 3 is provided on the measurement table, the stopping accuracy of the sample feeding rond 4-4 of the feeding mechanism 4 is sufficient at approximately ±0.5 mm.

(2) Tilt Setting Mechanism FIG. 3(a) is a perspective view showing an example of setting the sample surface accurately perpendicular to the laser beam irradiated onto the sample surface. The measurement table 9 is composed of an inner table 9-1 on which the adapter 2 is mounted and an outer tape #19-3, and the inner tape A/9-1 is engaged with the outer table 9-3 via the shaft 9-2. The outer table 9-3 is connected to the shaft 9-
It is engaged with the fixed support part 7 via 4. Therefore, the inner table 9-1 is rotatable about each of the shafts 9-2, 9-4. Furthermore, the axes 9-2 and 9-4 are provided within a plane that includes the surface of the sample 1 on the inner table 9-1 (more precisely, on the adapter 2 above it), and are orthogonal to each other. . Note that the direction of the axis 9-2, 9-4 is X
, may be a direction having an appropriate angle (for example, 45°) with the Y direction.

The intersection point 01 on the extension of the axes 9-2 and 9-4 is set as the center of the table, and the sample 1 (either omitted in Fig. 3(a) or mounted on the adapter 2 as described above) is placed here. position. A highly rigid arm 9-5 is extended directly below from the fork point oI, and several steel balls 9-t3 are fired at its tip. The steel ball 9-6 is attached to the hook c+tsuku 10-1. l0-
2 in the X direction and Y direction, respectively.
It is possible to move in the direction.

Note that 9-7 and 9-8 are springs, and by configuring them as described above, it becomes possible to swing the surface of the measurement table 9 in all directions.

The above blocks 10-1 and 10-2 are precision X shown below,
It is driven by the Y feed mechanism 10. The details of the feeding mechanism 10 are shown in FIG. 3(b). Figure 3(b) shows X, Y
Although only the X direction feeding portion of the feeding mechanism 10 is shown,
The directional feed portion also has a completely similar configuration. Pulse motor 1
By hand rotation of the ball screw 10 directly connected to the ball screw 10-3, the ball nut 105 on the ball screw 10-4 moves in the Z direction. This movement is achieved by moving the block 1o-1 through the Taber sliding surface 1o-6 consisting of a slide guide.
is transformed so as to move it in the X direction. Also, if the angle that the Taber sliding animation 10-6 makes with the Z axis is A, block 1
A feed deceleration of 0-1 will be proportional to tan A.

In addition, on the actual flow side, in order to minimize play during feeding, each sliding surface 10-6.10-7.10-8°1
All slide guides are used for 0-9.

Next, error detection and feedback of perpendicularity to the laser beam will be explained. In FIG. 3(b), the incident laser beam 21 is specularly reflected on the surface of the sample 1, passes through the beam splitter 11, and passes through the beam splitter 11.
The light is received by the The position sensor 12 is adjusted in advance so that when the sample surface is exactly perpendicular to the incident source axis, the specularly reflected light is received at the center of the position sensor 12. If the surface of the sample 10 is tilted by an angle θ from the normal position, the specularly reflected beam will have an angle of 2θ with respect to the incident beam. (the optical path length up to the sensor 12). The light receiving position on the position sensor 12 is detected by the amplifier 13. The analog calculation unit 14 calculates the amount of displacement, inputs it to the control device 8 equipped with the microcomputer, and calculates the amount of displacement by the pulse motor 0.
-3 pulses and drives the block 10-1 to correct the tilt.

Here, the driving amount (ball null) of the ball screw 10-4 (movement amount of Ic)-5) is set to 2. If the steel ball arm length is l, the inclination angle θ of the sample 1 is expressed as θ tan A . Therefore, if 2 and A are small and l
By setting large, fine tilt adjustment becomes possible.

Note that, as described above, the above operation is exactly the same for movement in the Y direction.

(3) Z-direction positioning mechanism Although the height of the sample surface from the measurement optical system must always be kept constant, the height may fluctuate when measuring samples with different thicknesses or due to tilt adjustment. In some cases, it becomes necessary to correct the height of the entire foot measuring table. An example of this is shown in FIG.

Needless to say, the following operations are performed after performing the tilt correction.

In FIG. 4, the height of the surface of the sample 1° is detected, and the deviation from the reference position is fed back and corrected by the number of pulses of the pulse motor. The one-dimensional position sensor 18 receives the specularly reflected light of the laser beam 17 irradiated from obliquely upward onto the center point of the surface of the sample 10 by the laser oscillator 16', and the received position signal output is sent to the amplifier 19.
．． The signal is input to the control device 8 through the analog computing unit 20. The control device 8 drives the pulse motor 15-1 by an amount corresponding to the amount of height correction, and moves the height adjustment mechanism 15 up and down by that amount. The height adjustment mechanism 15 is a precision X shown in FIG. 3(b).
, is exactly the same as one side of the Y feed mechanism (it is a fissure).

According to the positioning mechanism of this embodiment, which is equipped with the above-mentioned XY direction positioning mechanism, 1 rotation setting mechanism, and Z direction positioning mechanism, for example, precise positioning with an XYZ positioning accuracy of ±1 μm or less than a one-plane tilt accuracy can be automatically performed. This could be done by operation.

It goes without saying that the present invention should not be limited to the above embodiments.

〔Effect of the invention〕

As described above, the present invention has the remarkable effect that it is possible to realize a positioning mechanism capable of extremely high precision positioning by using ordinary precision parts that are mostly available in vehicles. It is.

The positioning mechanism of the present invention also has the advantage that it can be easily controlled using a microcomputer and is extremely easy to automate.

[Brief explanation of the drawing]

FIG. 1(a) is a partially cutaway perspective view showing an example of a conventional positioning mechanism, FIG. 1(b) is a side view showing the narrow part, and FIGS.
FIG. 4 shows an embodiment of the present invention, and FIG. 2(a)
3(b) is a plan view showing the adapter feeding mechanism; FIG. 3(C) is a plan view showing the XY direction positioning mechanism; FIG. 3(a) is a perspective view showing the tilting rectangular mechanism; FIG. 4B is a side view showing the details thereof, and FIG. 4 is a side view showing the Z-direction positioning mechanism. 1: Sample, 2 Near doubler, 3: XY direction positioning mechanism, 4: Feeding mechanism, 5: Carrying out belt, 8: Control device, 9
: Bottle measuring table, lo: XY tree top feed mechanism, 11: Beam splitter, 12.18: Position sensor, 14.
20: Analog computing unit. 1st Fig. 3' 2nd Fig. 49- Fig. 2 (c) 4. Fig. 3 (b) Upper -m=・\

Claims (2)

[Claims] (1) In a mechanism for positioning a flat sample placed on a sample stage so that it has an inclination of a predetermined angle with respect to a reference direction, the sample stage is rotated about two axes that are perpendicular to each other. means for detecting the inclination of the sample surface by movably supporting the sample surface and detecting the direction of specularly reflected light on the sample surface of a laser beam irradiated onto the sample surface from the reference direction; A positioning mechanism characterized by comprising: means for adjusting the inclination of the sample stage based on the output of the means. (2) The positioning mechanism according to claim 1, wherein the predetermined angle is 90°.