JP2005172487A - Flatness measurement method and flatness measurement program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flatness measurement method and a flatness measurement program capable of correcting measurements, even in relation with mutual measurement lines. <P>SOLUTION: The flatness measuring method using serial three-point method is provided with processes as follows: a reference plane setting process for setting up the reference plane by measuring Z-coordinates of stoppable point of XY driving mechanism existing on an assumed triangle abc; a Y-line measurement process for measuring Y-line on a plurality of Y-coordinates so as to pass through the stoppable points; an X-line measurement process for measurement by setting X-line so as to pass through the X-coordinate measured in the Y-line measurement process; an X-line fitting process for fitting the X-line onto the Y-line; an XY-line fitting process for fitting the Y-line onto the reference surface integrating the X-line fitted to the Y-line; and a flatness computing process based on the measurements after the processes. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flatness measurement method and a flatness measurement program for measuring the flatness of a wafer, a photomask, or another object to be measured. In particular, the present invention is a high-precision flatness measurement method and flatness measurement program capable of measuring large-scale nm orders.

Conventionally, as a method of measuring straightness in nanometer order, a sequential three-point double-shearing heterodyne interferometry is known (for example, see Patent Document 1).
In this method, errors due to vibrations of the object to be measured and the interference optics themselves that occur during the movement of the interference optical system can be corrected, and straightness can be determined from nanometer order to sub-nanometer order.

This method has an advantage that, when the measurement is performed linearly, the transition between each measurement can be accurately measured, and the influence of mechanical vibration and laser fluctuation can be canceled.
In the measurement, the measurement is performed in a line shape at predetermined intervals, and after the measurement along the line is performed, the measurement is performed along another line parallel to the line.

Then, the difference in the distance from the light source to the object to be measured at the measurement point measured in a grid shape is measured, and based on the measurement result, the mesh-shaped curved object surface state having the grid is displayed on the monitor. Is displayed.
At the same time, the flatness within the predetermined area is also calculated.

JP 2001-165640 A

However, even when a heterodyne type shearing interferometer is used, when the measurement lines are compared with each other, there is a problem in that the inclination state in the height direction of each measurement line varies with a low correlation.
For this reason, there has been a problem that the surface shape of the object to be measured cannot be accurately monitored and accurate flatness cannot be calculated.

The present invention has been made on the basis of such a technical background, and has been made to overcome the above-described problems of the prior art.
That is, an object of the present invention is to provide a flatness measurement method and a flatness measurement program capable of correcting a measurement value even in a relationship between measurement lines.

  According to the first aspect of the present invention, there is provided a flatness measuring device having an XY driving mechanism that moves stepwise at predetermined intervals, and that adopts a three-point method to measure the Z-direction position of the object to be measured. The at least two sides of the triangle abc are such that the stop point of the XY drive mechanism other than the points a, b, and c is equal to the Y coordinate of the stop points. Assuming that the triangle abc is set so that it can be set, the Z coordinates of points a, b, and c and the stop points of the XY drive mechanism other than points a, b, and c existing on the sides of the triangle abc A reference plane setting step of measuring a Z coordinate and setting a reference plane using the measured Z coordinate, and a Y line along the X-axis direction intersects two of the sides of the triangle abc (or With triangles abc) The Y line measurement process in which the Y line is measured at a plurality of Y coordinates so as to pass through the stoppable point of the XY drive mechanism existing in the X line, and the X line so as to pass through the X coordinate position measured in the Y line measurement process And the X line measurement step of measuring the Z coordinates of a plurality of stoppable points on the X line along the Y-axis direction, and the intersection position of the X line and the Y line, The Z coordinate is transformed to match or approximate the Z coordinate of the intersection position on the Y line, and the X line is fitted to the Y line in the X line fitting process. XY line frame that fits the Y line to the reference plane at the intersection of the Y line and the triangle abc while integrating the X line. And potting step consists in having a flatness calculating step of calculating a flatness on the basis of the measurement result after the XY line fitting process.

  According to a second aspect of the present invention, there is provided a flatness measuring instrument having an XY driving mechanism that moves stepwise at predetermined intervals and that adopts a three-point method to measure the Z-direction position of an object to be measured. The at least two sides of the triangle abc are such that the stop point of the XY drive mechanism other than the points a, b, and c is equal to the Y coordinate of the stop points. Assuming that the triangle abc is set so that it can be set, the Z coordinates of points a, b, and c and the stop points of the XY drive mechanism other than points a, b, and c existing on the sides of the triangle abc A reference plane setting step of measuring a Z coordinate and setting a reference plane using the measured Z coordinate, and a Y line along the X-axis direction intersects two of the sides of the triangle abc (or With triangles abc) The Y line measurement process for measuring the Y line at a plurality of Y coordinates so as to pass through the stop point of the XY drive mechanism existing in the X line, and the X line so as to pass through the X coordinate position measured in the Y line measurement process An X-line measuring step of setting and measuring the Z-coordinates of a plurality of stoppable points on the X-line along the Y-axis direction, and the Z-coordinate of the intersection position of the Y-line at the intersection of the Y-line and the triangle abc Is converted to be equal to the Z coordinate of the intersection position of the reference plane, and the Y line fitting process for fitting the Y line to the reference plane, and the intersection position of the X line at the intersection position of the X line and the Y line X is transformed so that the Z coordinate of the Y line becomes equal to the Z coordinate of the intersection position of the Y line after the Y line fitting process, and the X line is fitted to the Y line. Consists in having a push-in fitting step, a flatness calculating step of calculating a flatness on the basis of the measurement result after the X-line fitting process, the.

  A third aspect of the invention resides in that in the flatness measuring method according to the first or second aspect, the number of Y lines to be measured in the Y line measuring step is two.

  According to a fourth aspect of the present invention, in the flatness measuring method according to the first or second aspect, one side of the triangle abc is arranged in parallel to the X axis, and in the Y line measuring step, The Y line measurement of the same Y coordinate is performed.

  The invention according to claim 5 has an rθ drive mechanism that moves and rotates stepwise at predetermined intervals, and adopts a three-point method successively to measure the Z-direction position of the object to be measured, Is a method for measuring flatness according to the above, wherein there are stop points of the rθ drive mechanism other than the points a, b, and c on the sides of the triangle abc, and the stop point and the points a, b, or c. Are assumed to exist on one reference line passing through the coordinate origin, the Z coordinates of points a, b, and c, and the triangle abc other than points a, b, and c and the reference A reference plane setting step of measuring a Z coordinate of an intersection position with the line and setting a reference plane using the measured Z coordinate, and a reference for measuring the Z coordinate with a plurality of r coordinates on the reference line The line measurement process and the r coordinate position measured in the reference line measurement process are passed. Thus, in the circle line measurement step of measuring the Z coordinates of a plurality of stoppable points along the θ direction and the intersection position of the reference line and the circle line, the Z coordinate of the intersection position on the circle line is set on the reference line. The circle line fitting step of fitting the circle line to the reference line and the circle line fitted to the reference line in the circle line fitting step are integrated, It has an rθ line fitting step of fitting a reference line to a reference plane at the intersection of the line and the triangle abc, and a flatness calculation step of calculating flatness based on a measurement result after the rθ line fitting step. .

  The invention described in claim 6 has an rθ drive mechanism that moves and rotates stepwise at predetermined intervals, and adopts a three-point method successively to measure the Z-direction position of the object to be measured, Is a method for measuring flatness according to the above, wherein there are stop points of the rθ drive mechanism other than the points a, b, and c on the sides of the triangle abc, and the stop point and the points a, b, or c. Are assumed to be on a single reference line passing through the coordinate origin, the Z coordinates of points a, b and c, and the triangle abc and reference line other than points a, b and c A reference plane setting step of measuring the Z coordinate of the intersection position of the two and setting a reference plane using the measured Z coordinate, and a reference line measurement for measuring the Z coordinate at a plurality of r coordinates on the reference line The reference line is the reference at the intersection of the process and the reference line and the triangle abc. In the reference line fitting process for fitting to the surface, and the intersection position of the reference line and the circle line, the Z coordinate of the intersection position on the circle line matches the Z coordinate of the intersection position on the reference line after the reference line fitting process Thus, the present invention has a circle line fitting step of performing coordinate transformation so as to fit a circle line to a reference line, and a flatness calculation step of calculating flatness based on a measurement result after the circle line fitting step.

  According to a seventh aspect of the present invention, in the flatness measuring method according to the fifth or sixth aspect, at the two intersection positions of the reference line and the circle line, both the Z coordinate measurement is performed in the reference line measuring step. And the fitting of the reference line and the circle line is performed at the intersection position of the two places.

  According to an eighth aspect of the present invention, in the flatness measuring method according to the fifth or sixth aspect, a triangle that allows a plurality of the reference lines to be drawn is assumed, and the plurality of reference lines are used as a reference plane. The fitting is performed so that the circle lines are fitted to a plurality of reference lines.

  According to a ninth aspect of the present invention, in the flatness measuring method according to the fifth aspect of the invention, the surface state of the object to be measured is displayed in a mesh form on the monitor using the measurement result after the rθ line fitting step. Exist.

  According to a tenth aspect of the present invention, in the flatness measuring method according to the sixth aspect, using the measurement result after the circle line fitting step, the surface state of the object to be measured is displayed as a mesh on the monitor. Exist.

  The eleventh aspect of the present invention is the flatness measurement method according to the first, second, fifth, or sixth aspect, wherein in the reference plane setting step, a triangle composed of vertices a, b, and c is formed. Instead of assuming a polygon, a circle or a circle is assumed, the Z coordinates of four or more positions are measured, a plane close to the measurement point is obtained, and used as a reference plane.

  According to a twelfth aspect of the present invention, the adjacent planes are obtained by a least square method.

  A thirteenth aspect of the present invention is the flatness measurement method according to the first, second, fifth, or sixth aspect, wherein the measurement position is changed when the measurement position is changed in the reference plane setting step. Rotating a turntable on which an object is placed.

  According to a fourteenth aspect of the present invention, the flatness measuring method according to the first to thirteenth aspects is executed by using a flatness measuring device.

  In addition, as long as the objective of this invention is met, the structure which combined the said claim suitably is also employable.

  According to the present invention, by fitting the X line to the Y line and bringing the mesh shape to the position of the reference plane, the measurement value can be corrected even in the relationship between the measurement lines, The flatness of the entire sample surface can be accurately measured with simple calculation and a small number of measurement points.

In particular, by making a stoppable point at which the XY drive mechanism stops on the side of the triangle abc, the Z coordinate of the intersection position of the side of the triangle abc and the Y line can be linearly calculated from the measurement results of other positions. Since it is not necessary to perform the calculation of approximation by interpolation or the like, the calculation accuracy of flatness can be improved.
In addition, the same effect can be obtained even in the rθ plane.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
FIG. 1 shows a flatness measuring apparatus 1 for carrying out a flatness measuring method according to an embodiment of the present invention.

The flatness measuring device 1 is a device that measures flatness using light.
Further, the flatness measuring device 1 is a heterodyne type sharing interferometer, and the measurement is sequentially performed by a three-point method.
Further, the flatness measuring apparatus 1 has a base 2, and a pair of guide rails 3 parallel to each other are laid on the base 2.

The guide rail 3 is formed in an L-shape, and a guide bar 4 is provided on the inner side of the L-shape, and the X-axis movable table 5 is reciprocated along the guide bar 4. ing.
Further, a pair of L-shaped guide rails 6 parallel to each other are also provided on the X-axis direction movable table 5, and the Y-axis direction movable table 7 reciprocates along the guide rail 6.

A rotary table 8 is placed on the Y-axis direction movable table 7. And the measurement position of a to-be-measured object is changed by mounting a to-be-measured object in the rotation part 8A, and driving the X-axis direction movable stand 5, the Y-axis direction movable stand 7, and the rotation part 8A.
The X-axis direction movable table 5 and the Y-axis direction movable table 7 are driven using, for example, the principle of a linear motor in order to perform precise driving.

For example, a stepping motor is used to drive the rotating unit 8A.
If a stepping motor is used, it rotates in steps at predetermined intervals, that is, it rotates every minute angle, and the object to be measured can be rotated at an accurate angle.

On one end side of the base 2, an upright portion 9 is provided in an inverted L shape, and a head 10 for irradiating the object to be measured with light for measuring flatness is provided at the tip of the L shape. .
Various components for executing the double shearing heterodyne method are incorporated in the head 10.
Therefore, three light beams are irradiated on the object to be measured.

By adopting this method, it is possible to reduce the influence of mechanical vibration and laser fluctuation during measurement.
A cable 11 is connected to the flatness measuring apparatus 1, and a computer 12 is connected to one end of the cable 11.
The flatness is calculated by the computer 12 in accordance with a command from the flatness measurement program, and the result is displayed on the monitor 13.

Hereinafter, a case where the measurement surface of the object to be measured is an XY plane and an rθ plane will be described.
[When the measurement surface of the object to be measured is an XY plane]
(First processing flow)
FIG. 2 shows the flow of the first processing by the flatness measuring instrument 1 of the present invention.
First, in step S10, preparation for starting measurement is performed.
Hereinafter, this preparation step will be described in detail with reference to FIG.

First, the flatness measuring apparatus 1, the computer 12, and the monitor 13 are turned on, and the object to be measured is placed on the rotating unit 8 </ b> A of the rotary table 8.
Next, the object to be measured is placed directly below the head 10 that emits light by moving the XY drive mechanism.

Next, in step S11, a reference surface shape is selected.
Specifically, a screen as shown in FIG. 3 is displayed on the monitor 13.
The triangle displayed in the number 1 on the screen is an isosceles triangle of θ≈54 °.
The triangle displayed in the number 2 on the screen is a regular triangle of θ = 60 °.
The figure displayed in the number 3 on the screen is a circle.
The figure displayed in the number 4 on the screen is a square.
Here, the number 1 is selected.

  Next, in step S12, as shown in FIG. 4, a pending screen as to whether or not measurement can be started is displayed. If yes, "Yes" is selected.

Next, in step S13, a reference plane setting process is executed.
In this step, at least two of the sides of the triangle abc, the stop points of the XY drive mechanism other than the points a, b, and c can be set so that the Y coordinates of the stop points are equal. In addition, assuming the triangle abc, the Z coordinates of the points a, b, and c, and the Z coordinates of the stop points of the XY drive mechanism other than the points a, b, and c existing on the sides of the triangle abc, , And a reference plane is set using the measured Z coordinate.

Here, the triangle selected in step S11 is applied as an example with reference to FIG.
The triangle of No. 1 is θ≈54 °, but is exactly an isosceles triangle with a ratio of height to hypotenuse of 8: 9.
The reason for this angle is to allow the sides of the triangle abc to pass through the stoppable points that are the intersection positions of the X direction and the Y direction, such as points d and e.

Assuming a triangle that can set the d and e points, which are points that can be stopped (intersections of grids) other than the points a, b, and c, so that their Y coordinates are equal. To do.
Then, the Z coordinates of points a to e are measured, and a reference plane is set based on the measurement result.

At that time, a triangle passing through points a, b, and c is set as a reference plane.
In addition, based on the measurement result of 5 points | pieces, you may obtain | require the plane close | similar to 5 points | pieces by the least square method.

Next, in step S14, the Y line measurement process is executed.
In this process, the Y line along the X-axis direction passes through the stop point of the XY drive mechanism existing on the side of the triangle abc so that two of the sides of the triangle abc intersect (or have continuous points). Y line measurement is performed with a plurality of Y coordinates.

Here, it demonstrates concretely using FIG.
Assuming one Y line so as to pass through the points d and e determined in step S13, that is, to intersect two of the sides of the triangle abc, (x, y) = (1, 12) Measure the points (23, 12).

Further, assume that another Y line passes through the points b and c, that is, has two continuous points of the sides of the triangle abc, and (x, y) = (1, 4 ) To (23, 4) are measured.
In this way, one side of the triangle abc is arranged in parallel to the X axis, and in the Y line measurement process, Y line measurement of the same Y coordinate as the one piece is performed, so that the interval between Y lines is increased as much as possible. Therefore, accurate flatness measurement capable of covering a wide measurement area can be performed.

Next, in step S15, an X-line measurement process is executed.
Here, the Z coordinates of a plurality of stoppable points are measured along the Y-axis direction so as to pass through the measurement points measured in the Y line measurement process.

Here, it demonstrates concretely using FIG.
X coordinate positions (x, y) = (1, 4) to (23, 4) and (x, y) = (1, 12) to (23, 12) measured in the Y line measurement process of step S14. X-line measurement is performed along the Y-axis direction so as to pass.
At this time, measurement is performed at each point from y = 1 to 23 for each X line.
In addition, the mark of the measured position is abbreviate | omitted in the figure.

Next, in step S16, an X-line fitting process is executed.
In this step, at the intersection position of the X line and the Y line, the Z coordinate of the intersection position on the X line is coordinate-converted so as to coincide with the Z coordinate of the intersection position on the Y line, and the X line is converted to the Y line. To fit.

That is, at the intersection position ((x, y) = (1, 4) to (23, 4), (1, 12) to (23, 12)) of the X line and the Y line, the intersection point on the X line. Coordinate conversion is performed so that the Z coordinate of the position coincides with the Z coordinate of the intersection position of the Y line, specifically, parallel translation.
Then, a grid-like net is formed.
Note that a method of approximating three or more Y lines and approximating the X line to three or more Y lines by a least square method or the like may be used.

Next, in step S17, an XY line fitting process is executed.
In this step, the Y line is fitted to the reference plane set in step S4, that is, the points b to e of the triangle abc, while integrating the X line fitted to the Y line in the X line fitting step of step S16.

Next, in step S18, the measurement result after the XY line fitting process is displayed on the monitor 13 three-dimensionally as shown in FIG.
The grid indicated by the thin lines is the reference plane S, and the black circles are measurement points.
At the same time, the flatness is calculated from the data of the black circle points.

  As mentioned above, by bringing the mesh-like shape by the X-line fitting process to the position of the reference plane, the measured value can be corrected even in the relationship between measurement lines, simple calculation and few measurements The flatness of the entire sample surface can be accurately measured by the points.

In particular, on the sides of the triangle abc, the points d and e, which are the points where the XY drive mechanism stops, exist so that the Z coordinate of the intersection point between the side of the triangle abc and the Y line can be changed. Therefore, it is not necessary to perform a calculation of approximation by linear interpolation or the like from the measurement result of the position, so that the flatness calculation accuracy can be improved.
Further, since the surface state of the object to be measured is displayed in a mesh shape on the monitor 13, the surface state of the sample can be grasped visually and accurately.

(Second processing flow)
FIG. 9 shows the flow of the second processing by the flatness measuring instrument 1 of the present invention.
Steps S20 to S25 are the same as the flow of the first process, and thus description thereof is omitted.
The difference between the first process flow and the second process flow is that the fitting process is different.

In the second processing flow, a Y line fitting process is executed in step S26.
In this step, at the intersection point of the Y line and the triangle abc, coordinate transformation is performed so that the Z coordinate of the intersection position of the Y line becomes equal to the Z coordinate of the intersection position of the triangle abc, and the Y line is fitted to the reference plane. To do.
Here, it demonstrates concretely.

  In the intersection position ((x, y) = (4, 4), (8, 12), (16, 12), (20, 4)) between the Y line and the triangle abc, the intersection position on the Y line The coordinate is converted, specifically translated so that the Z coordinate coincides with the Z coordinate of the intersection position existing on the side of the triangle abc.

Next, in step S27, an X-line fitting process is executed.
In this process, at the intersection position of the X line and the Y line, coordinate transformation is performed so that the Z coordinate of the intersection position of the X line becomes equal to the Z coordinate of the intersection position of the Y line after fitting. Fitting to the line.

That is, at the intersection position ((x, y) = (1, 4) to (23, 4), (1, 12) to (23, 12)) of the X line and the Y line, the intersection point on the X line. The coordinate of the position is converted so that it coincides with the Z coordinate of the intersection position of the Y line after the Y line fitting process, specifically, it is translated.
Then, a grid-like net is formed.

  The flow of the second process has the same effect as the flow of the first process.

(Third processing flow)
FIG. 10 shows a third processing flow by the flatness measuring instrument 1 of the present invention.
First, in step 30, as in step S1 of the first processing flow, preparation for starting measurement is performed.

Next, in step S31, the reference surface shape shown in FIG. 3 is selected.
Here, the number 1 is selected.

  Next, in step S32, a pending screen as to whether or not measurement can be started is displayed as shown in FIG. 4. If yes, "Yes" is selected.

  Next, in step S33, a reference plane setting process is executed in the same manner as in step S4.

Next, in step S34, the Y line measurement process is executed.
In this process, the Y line along the X-axis direction passes through the stop point of the XY drive mechanism existing on the side of the triangle abc so that two of the sides of the triangle abc intersect (or have continuous points). Y line measurement is performed with a plurality of Y coordinates.

Here, it demonstrates concretely using FIG.
Assume that one Y line passes through the points d and e determined in step S33, that is, intersects with two of the sides of the triangle abc, and (x, y) = (4, 12) to The point (20, 12) is measured.

  Further, assume that another Y line passes through the points b and c, that is, has two continuous points of the sides of the triangle abc, and (x, y) = (4, 4 ) To (20, 4) are measured.

Next, in step S35, an X-line measurement process is executed.
The Z coordinates of a plurality of stoppable points are measured along the Y-axis direction so as to pass the X coordinate position measured in the Y line measurement process.

Here, it demonstrates concretely using FIG.
The X coordinate positions (x, y) = (4, 4) to (20, 4) and (x, y) = (4, 12) to (20, 12) measured in the Y line measurement process of step S34. X-line measurement is performed along the Y-axis direction so as to pass.
At this time, measurement is performed at each point from x = 1 to 23 for each X line.
In addition, the mark of the measured position is abbreviate | omitted in the figure.

Next, in step S36, measurement is performed along the Y line passing through a point marked with a white square mark, which is the point where the measurement was performed in the X line measurement step in FIG.
Specifically, as shown by black circles in FIG. 13, (x, y) = (1, 8) to (3, 8), (21, 8) to (23, 8), (1, 16) Measure the positions of (3, 16), (21, 16) to (23, 16).

Next, in step S37, the X-line measurement process is executed again.
The Z coordinates of the plurality of stoppable points are measured along the Y-axis direction so as to pass the X coordinate position measured in the Y line measurement step in step S36.

Here, it demonstrates concretely using FIG.
X coordinate position (x, y) = (1, 8) to (3, 8), (21, 8) to (23, 8), (1, 16) to (X) measured in the Y line measurement step of step S36 X line measurement is performed along the Y-axis direction so as to pass through (3, 16) and (21, 16) to (23, 16).
At this time, measurement is performed at each point from y = 1 to 23 for each X line.
In addition, the mark of the measured position is abbreviate | omitted in the figure.

Next, in step S38, various fittings are performed.
First, the X line (x = 1 to 3, 21 to 23) measured in step S37 is fitted to the Y line (y = 8, 16).
Next, the Y line (y = 8, 16) in which the X line (x = 1-3, 21-23) is integrated is changed to (x, y) = (4, 8), (4, 16), ( Fitting is made to the X line (x = 4, 20) at the points 20, 8) and (20, 16).

Further, the line group fitted twice and the other X lines (x = 5 to 19) are fitted to the Y line (y = 4, 12).
Finally, all these lines are fitted to the reference plane at the positions (x, y) = (4, 4), (8, 12), (16, 12), (20, 4), The fitting ends.

Note that, as described above, the Y line is measured at the position of y = 8, 16 as compared with the case of measuring at the position of y = 4, 12, but the width in the Y direction is the same. It is because it can measure.
That is, if measurement is performed at the position y = 8, 16, the error in the entire measurement region can be reduced as compared with the case where measurement is performed at the position y = 4, 12.

In addition, the above-described fitting order can be changed as appropriate.
For example, the fitting order may be reversed, and the Y line (y = 4, 12) may be fitted to the triangle abc first.

  Next, in step S39, the measurement result after the fitting process is displayed three-dimensionally as shown in FIG.

In the first to third processing flows described above, the example in which the triangle displayed on the screen No. 1 is an isosceles triangle of θ≈54 ° has been described. However, the numbers 2 to 4 are selected. However, the same processing is performed.
In particular, the number 2 equilateral triangle is suitable for securing a large number of stoppable points on the hypotenuse of the triangle.

In the hypotenuse of the equilateral triangle, y increases by 2 as x increases by 1. Therefore, a stoppable point can be secured for each Y-direction width that is twice the minimum movement pitch of the XY drive mechanism.
Further, when measuring a circular surface, the method of number 3 is effective.
This is because the reference surface shape is also circular, so that variations in measurement errors in the circumferential direction can be suppressed, and all the parts to be measured can be included in the circle of number 3.

Similarly, when measuring a square surface, the method of number 4 is effective.
This is because the reference surface shape is also a square, and all the parts to be measured can be included in the square of number 4.
The shape of the triangle abc is not limited to the shape displayed on the monitor 13.

For example, a triangle whose base is not parallel to the X axis as shown in FIG. 15 may be used.
In short, each of the two Y lines may be a triangle that intersects two sides of the triangle at a stoppable point of the XY drive mechanism (or has a continuous point).
In the above-described embodiment, the example in which the moving direction of the X-axis movable table 5 is set to the longitudinal direction of the base 2 has been described. However, the moving direction of the Y-axis movable table 7 is set to the longitudinal direction of the base 2. It may be taken.

Further, the intersection angle between the X axis and the Y axis may not be 90 °.
That is, the X line may be a net-like shape that is inclined with respect to the Y line.

[When measuring surface of object to be measured is rθ plane]
(4th process flow)
FIG. 16 shows a fourth processing flow by the flatness measuring instrument 1 of the present invention.
Steps S40 to S42 are the same as the flow of the first process, and thus the description thereof is omitted.
The fourth processing flow is different in that the first to third flows adopt the XY coordinates while the rθ coordinates are adopted.

In the fourth process flow, a reference plane setting step is executed in step S43.
In this step, there is a stop point of the rθ drive mechanism other than the points a, b, and c on the side of the triangle abc, and the stop point and the points a, b, or c have the coordinate origin. Assuming that a triangle exists on one passing reference line, the Z position of points a, b and c, and the position of the intersection of the triangle abc other than points a, b and c and the reference line And the reference plane is set using the measured Z coordinate.

Here, with reference to FIG. 17, the triangle selected in step S41 (assumed to be a regular triangle of number 2) is applied as an example.
On the sides of the triangle abc determined in step S43, there are stop points (d points) of the rθ drive mechanism other than the points a, b and c, and the points d and b pass through the coordinate origin 1 Assume a triangle to be on the reference line of the book.
Then, the Z coordinates of the points a to d are measured, and a reference plane is set based on the measurement result.

  At that time, a triangle passing through points a, b, and c may be used as a reference plane. However, based on the measurement results of the four points, more accurate measurement is obtained by obtaining a plane close to the four points by the least square method. It can be carried out.

Next, in step S44, a reference line measurement process is executed.
In this step, as shown in FIG. 18, the Z coordinate is measured at a plurality of r coordinates on the reference line.

Next, in step S45, a circle line measurement process is executed.
Here, the Z coordinates of a plurality of stoppable points are measured along the θ direction so as to pass the r coordinate position measured in the reference line measurement step.
That is, as shown in FIG. 19, the circle line measurement is performed along the θ direction so as to pass through the point (black circle in the figure) measured in the reference line measurement process in step S44.

Next, in step S46, a circle line fitting process is executed.
In this process, at the intersection position of the reference line and the circle line, the Z coordinate of the intersection position on the circle line is coordinate-transformed so as to coincide with the Z coordinate of the intersection position on the reference line, and the circle line is converted to the reference line. To fit.
For example, for a circle line with a radius of 9, fitting is performed at the intersection position of r = 9, θ = 30 °, r = 9, θ = 210 °.
Note that it is possible to assume two or more reference lines and approximate the circle line to two or more reference lines by the least square method or the like.

Next, in step S47, an rθ line fitting process is executed.
In this step, the reference line is fitted to the reference plane at the intersection of the reference line and the triangle abc while integrating the circle line fitted to the reference line in the circle line fitting step.

Note that the above-described fitting order can be changed as appropriate.
For example, the fitting order may be reversed, the reference line may be fitted to the reference plane, and then the circle line may be fitted to the reference line after coordinate conversion.

Next, in step S48, the measurement result after the rθ line fitting process is displayed three-dimensionally on the monitor 13 as shown in FIG.
The grid indicated by the thin lines is the reference plane S, and the black circles are measurement points.
At the same time, the flatness is calculated from the data of the black circle points.

  In the fourth processing flow, the measurement value can be corrected even in the relationship between the measurement lines by bringing the mesh-like one formed by the rθ line fitting process to the position of the reference plane, and the measurement value can be corrected easily. The flatness of the entire sample surface can be accurately measured by calculation and a small number of measurement points.

In the above-described fourth processing flow, the example in which the equilateral triangle displayed on the screen number 2 is selected has been described, but the same processing is performed even if the numbers 1, 3, and 4 are selected.
In particular, when the reference surface shape is a circle, variations in measurement error in the circumferential direction can be suppressed.

Further, the shape of the triangle abc is not limited to the shape displayed on the monitor 13.
Furthermore, although the example in which the circle line is fitted to the reference line has been described, a spiral line instead of the circle line may be fitted to the reference line.

Although the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible.
For example, instead of assuming a triangle consisting of vertices a, b, and c, assume a polygon or a circle, measure Z coordinates at four or more positions, find a plane close to the measurement point, and use it as a reference plane. Also good.

  In this way, the area of the reference surface can be increased compared to a triangle, and more accurate flatness measurement can be performed. In particular, in the case of a circle, the circumferential position in the XY plane and the rθ plane can be stabilized.

Further, although the flatness measuring apparatus 1 has been described with respect to an example of a heterodyne type sharing interferometer, that is, an optical sequential three-point system, the present invention is not limited to this.
For example, a mechanical sequential three-point method using three displacement meters may be used.

Moreover, although the example which rotates the rotation part 8A of the turntable 8 by the r (theta) drive mechanism was demonstrated, you may make it the structure which rotates a head side.
Similarly, the example in which the X-axis direction movable table 5 and the Y-axis direction movable table 7 are moved by the XY drive mechanism has been described, but the head side may be moved.

It is explanatory drawing which shows the flatness measuring apparatus for enforcing the measuring method of flatness which concerns on one Embodiment of this invention. It is explanatory drawing which shows the flow of the 1st process by the flatness measuring device of this invention. It is explanatory drawing which shows the reference plane shape selection screen displayed on the monitor of FIG. It is explanatory drawing which shows the pending screen displayed on the monitor of FIG. It is a figure for demonstrating a reference plane setting process. It is a figure for demonstrating a Y line measurement process. It is a figure for demonstrating a X line measurement process. It is explanatory drawing which shows the measurement result after the XY line fitting process displayed on a monitor three-dimensionally. It is explanatory drawing which shows the flow of the 2nd process by the flatness measuring device of this invention. It is explanatory drawing which shows the flow of the 3rd process by the flatness measuring device of this invention. It is a figure for demonstrating a Y line measurement process. It is a figure for demonstrating a X line measurement process. It is a figure for demonstrating a Y line measurement process. It is a figure for demonstrating a X line measurement process. It is a figure for demonstrating the modification of the triangle assumed in a reference plane setting process. It is explanatory drawing which shows the flow of the 4th process by the flatness measuring device of this invention. It is a figure for demonstrating a reference plane setting process. It is a figure for demonstrating a reference line measurement process. It is a figure for demonstrating a circle line measurement process. It is explanatory drawing which shows the measurement result after the r (theta) line fitting process displayed on a monitor three-dimensionally.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flatness measuring apparatus 2 Base 3 Guide rail 4 Guide bar 5 X-axis direction movable stand 6 Guide rail 7 Y-axis direction movable stand 8 Rotating table 8A Rotating part 9 Standing part 10 Head 11 Cable 12 Computer 13 Monitor S Reference plane

Claims (14)

A flatness measuring method using a flatness measuring instrument that has an XY drive mechanism that moves stepwise at predetermined intervals and that sequentially measures the Z-direction position of an object to be measured using a three-point method,
In at least two sides of the triangle abc, the triangle abc is set such that the stop points of the XY drive mechanism other than the points a, b, and c can be set so that the Y coordinates of the stop points are equal to each other. Assuming
Z coordinates of points a, b, and c, and Z coordinates of points where the XY drive mechanism other than the points a, b, and c existing on the side of the triangle abc can be stopped,
Measure and
A reference plane setting step of setting a reference plane using the measured Z coordinate;
The Y line along the X-axis direction intersects with two of the sides of the triangle abc (or has a continuous point) and passes through the stop point of the XY drive mechanism existing on the side of the triangle abc. Y line measurement process for measuring the Y line at a plurality of Y coordinates,
An X-line measuring step of setting the X-line so as to pass through the X-coordinate position measured in the Y-line measuring step, and measuring the Z coordinates of a plurality of stoppable points on the X line along the Y-axis direction;
At the intersection point of the X line and the Y line, the Z coordinate of the intersection point position on the X line is transformed to match or approximate the Z coordinate of the intersection point position on the Y line, and the X line is fitted to the Y line An X-line fitting process,
XY line fitting step of fitting the Y line to the reference plane at the intersection position of the Y line and the triangle abc while integrating the X line fitted to the Y line in the X line fitting step;
A flatness calculating step of calculating flatness based on the measurement result after the XY line fitting step;
A flatness measuring method characterized by comprising: A flatness measuring method using a flatness measuring instrument that has an XY drive mechanism that moves stepwise at predetermined intervals and that sequentially measures the Z-direction position of an object to be measured using a three-point method,
In at least two sides of the triangle abc, the triangle abc is set such that the stop points of the XY drive mechanism other than the points a, b, and c can be set so that the Y coordinates of the stop points are equal to each other. Assuming
Z coordinates of points a, b, and c, and Z coordinates of points where the XY drive mechanism other than the points a, b, and c existing on the side of the triangle abc can be stopped,
Measure and
A reference plane setting step of setting a reference plane using the measured Z coordinate;
The Y line along the X-axis direction intersects with two of the sides of the triangle abc (or has a continuous point), and passes through the stop point of the XY drive mechanism existing on the side of the triangle abc. Y-line measurement process for measuring the Y-line at a plurality of Y-coordinates;
An X-line measuring step of setting the X-line so as to pass through the X-coordinate position measured in the Y-line measuring step, and measuring the Z coordinates of a plurality of stoppable points on the X line along the Y-axis direction;
Y-line fitting that performs coordinate transformation so that the Z coordinate of the intersection position of the Y line is equal to the Z coordinate of the intersection position of the reference plane at the intersection position of the Y line and the triangle abc, and fitting the Y line to the reference plane Process,
At the intersection position of the X line and the Y line, coordinate conversion is performed so that the Z coordinate of the intersection position of the X line becomes equal to the Z coordinate of the intersection position of the Y line after the Y line fitting process, and the X line is converted to the Y line. An X-line fitting process for fitting to
A flatness calculating step of calculating flatness based on the measurement result after the X-line fitting step;
A flatness measuring method characterized by comprising: In the flatness measuring method according to claim 1 or 2,
The flatness measuring method, wherein the number of Y lines measured in the Y line measuring step is two. In the flatness measuring method according to claim 1 or 2,
One side of the triangle abc is arranged parallel to the X axis,
A flatness measurement method, wherein a Y line measurement of the same Y coordinate as the one piece is performed in the Y line measurement step. A flatness measurement method using a flatness measuring device that has an rθ drive mechanism that moves and rotates stepwise at predetermined intervals, and that successively adopts a three-point method to measure the Z-direction position of an object to be measured,
On the side of the triangle abc, there is a stop point of the rθ drive mechanism other than the points a, b, and c, and the stop point and the point a, b, or c pass through the coordinate origin. Assuming a triangle to be on the baseline of
the Z coordinates of the points a, b, and c, and the Z coordinates of the intersection position of the triangle abc other than the points a, b, and c and the reference line;
Measure and
A reference plane setting step of setting a reference plane using the measured Z coordinate;
A reference line measurement step of measuring the Z coordinate at a plurality of r coordinates on the reference line;
A circle line measuring step of measuring Z coordinates of a plurality of stoppable points along the θ direction so as to pass through the r coordinate position measured in the reference line measuring step;
A circle for fitting the circle line to the reference line by converting the Z coordinate of the intersection position on the circle line so as to match the Z coordinate of the intersection position on the reference line at the intersection position of the reference line and the circle line A line fitting process;
An rθ line fitting step of fitting the reference line to the reference plane at the intersection of the reference line and the triangle abc, while integrating the circle line fitted to the reference line in the circle line fitting step;
A flatness calculation step of calculating flatness based on a measurement result after the rθ line fitting step;
A flatness measuring method characterized by comprising: A flatness measurement method using a flatness measuring device that has an rθ drive mechanism that moves and rotates stepwise at predetermined intervals, and that successively adopts a three-point method to measure the Z-direction position of an object to be measured,
On the side of the triangle abc, there is a stop point of the rθ drive mechanism other than the points a, b, and c, and the stop point and the point a, b, or c pass through the coordinate origin. Assuming a triangle on the reference line
the Z coordinates of the points a, b, and c, and the Z coordinates of the intersection position of the triangle abc other than the points a, b, and c and the reference line;
Measure and
A reference plane setting step of setting a reference plane using the measured Z coordinate;
A reference line measurement step of measuring the Z coordinate at a plurality of r coordinates on the reference line;
A reference line fitting step of fitting the reference line to the reference plane at the intersection point of the reference line and the triangle abc;
At the intersection position of the reference line and the circle line, the Z coordinate of the intersection position on the circle line is coordinate-converted so as to coincide with the Z coordinate of the intersection position on the reference line after the reference line fitting process, and the circle line is A circle line fitting process for fitting to a reference line;
A flatness calculation step of calculating flatness based on the measurement results after the circle line fitting step;
A flatness measuring method characterized by comprising: In the flatness measuring method according to claim 5 or 6,
At the two intersection points of the reference line and the circle line,
Both Z coordinate measurement is performed in the reference line measurement process,
A flatness measuring method, wherein fitting of a reference line and a circle line is performed at the two intersection positions. In the flatness measuring method according to claim 5 or 6,
Assuming a triangle that can draw a plurality of the reference lines,
Fitting the plurality of reference lines to approximate the reference plane,
A flatness measurement method characterized in that a circle line is fitted to a plurality of reference lines. The flatness measuring method according to claim 5,
A flatness measuring method, comprising: using a measurement result after the rθ line fitting step, displaying a surface state of an object to be measured on a monitor in a mesh shape. In the flatness measuring method according to claim 6,
A flatness measurement method, comprising: using a measurement result after the circle line fitting step, displaying a surface of an object to be measured in a mesh shape on a monitor. In the flatness measuring method according to claim 1, claim 2, claim 5, or claim 6,
In the reference plane setting step, instead of assuming a triangle composed of vertices a, b, and c, a polygon or a circle is assumed, Z coordinates at four or more positions are measured, and a plane close to the measurement point is determined. A flatness measuring method characterized in that it is obtained as a reference plane. The flatness measurement method according to claim 11,
The flatness measuring method, wherein the adjacent planes are obtained by a least square method. In the flatness measuring method according to claim 1, claim 2, claim 5, or claim 6,
In the reference plane setting step, a flatness measurement method characterized by rotating a rotary table on which an object to be measured is placed when changing a measurement position.   The program for performing the flatness measuring method of Claim 1 thru | or 13 using a flatness measuring device.

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