JP2020056735A - Shape measurement method, shape measurement device, and article manufacturing method - Google Patents

Abstract

To provide a shape measurement method capable of performing precise shape measurement capable of effectively using multiple measurement results with different measurement directions such as a cross-section measurement, a circumference measurement for example while ensuring the measurement accuracy.SOLUTION: The shape measurement device has a linear stage, a rotary stage, and a probe. Using the shape measurement device, a piece of circumference measurement data is acquired by measuring along the multiple circumferential directions around the rotation axis of an object to be measured as the center (S201). Also, using the shape measurement device, a piece of diameter measurement data is acquired by measuring along multiple diameter directions at the indexing angle of multiple around the rotation axis of an object to be measured (S202). Using the circumference measurement data, an error in the diameter measurement data is corrected (S204, S205), and using the corrected data, an error in the circumference measurement data is corrected(S206).SELECTED DRAWING: Figure 2

Description

  The present invention provides a shape for performing shape measurement using a translation stage that linearly moves an object to be measured, a rotary stage that rotationally moves the object to be measured around a rotation axis, and a probe that traces the object to be measured. The present invention relates to a measuring method, a shape measuring device, and a method for manufacturing an article.

  In general, when measuring the surface shape of an optical element having a rotationally symmetric shape, for example, an aspherical lens, a shape measuring device that moves a contact or non-contact type probe along the lens surface and measures the surface shape from the movement locus. It has been known. This type of shape measuring apparatus includes, for example, a portal stage having at least two axes such as an axis for moving a work surface and an axis for positioning a probe on the work surface, and a work arranged at a lower part thereof. And a rotating shaft for rotating.

  In this type of shape measuring apparatus, as shown in FIG. 15, a probe is brought into contact with a work 1509, and an X-axis stage slider is driven to move the probe following a surface, thereby measuring a cross section of the work. Subsequently, the rotary stage is driven by an arbitrary angle to rotate the work, and similarly, the X-axis stage slider is driven to measure the cross section of the work. The drive of the rotary stage and the drive of the X-axis stage slider are repeated an arbitrary number of times. For example, when the rotary stage is rotated by a half turn, a plurality of cross-sectional measurements are performed on the work as shown in FIG. .

  Further, according to another method, as shown in FIG. 16, the X-axis stage slider and the Z-axis stage slider are driven to bring the probe into contact with, for example, substantially the outer periphery of the work 1509. Then, the rotary stage is driven to rotate the work 1509 to make one rotation, and the rotation angle data of the rotary stage and the position data of the Z-axis stage slider are acquired as equivalent to the circumference measurement data for one rotation. Subsequently, the X-axis stage slider is driven to move the probe by an arbitrary amount toward the center of the work 1509. Then, similarly, the rotary stage is driven to rotate, the probe makes the work 1509 make one round, and the rotation angle data of the rotary stage and the position data of the Z-axis stage slider are acquired. By repeating the movement of the X-axis stage slider and the rotation of the rotary stage, the surface measurement of the workpiece 1509 is performed in the form of a plurality of concentric circumference measurements as shown in FIG.

  However, according to the conventional measurement method as described above, there is a possibility that an error occurs in the shape due to the passage of time and the accompanying drift. In view of this point, as described in Patent Documents 1 and 2 below, a method for correcting a shape error caused by a drift such as a temperature while a probe traces the surface of a target work has been proposed.

  Further, according to the above-described conventional measurement method, an error may occur when the Z axis of the surface measurement of the work does not exactly coincide with the rotation axis of the work. Since an error occurs in the shape measurement due to the inconsistency of the rotation axes, a method of identifying and correcting the position of the rotation axis of the circumferential rotation in the coordinates of the cross-section measurement has been proposed as in Patent Document 3 below.

JP 2004-286507 A JP-A-2002-054921 JP 2014-132264 A

  In the configuration of Patent Document 1, the surface to be measured is measured so as to intersect with the trajectory data for measuring the surface, an error is obtained for the intersection, and the entire surface data is corrected. However, the configuration of Patent Document 1 has a problem in that data measured for correction is not used as surface data, and wasteful surface data measurement is performed. Therefore, high-density surface measurement may not be performed. As for the correction, the error near the intersection is processed as the entire error, so if there is an error near the intersection that does not require correction such as dust, it may affect the overall correction and increase the error. was there.

  In the configuration of Patent Document 2, the second pattern for performing the surface measurement and the first pattern for performing the correction are measured, and the error of the intersection is reduced by using the interpolation function in the first scanning pattern area. By doing so, there is a possibility that drift correction can be performed with relatively high accuracy. However, in the case of Patent Document 2, the data measured for correction is not used as the surface data, and there is a problem that useless surface data measurement is performed as described above.

  In the configuration of Patent Document 3 described above, the rotation axis of the rotary stage is used only for indexing and positioning of the work, and the rotation axis is calculated using an aspherical shape. However, a difference in dynamic runout occurs when the indexing is stopped and when the rotary drive is driven to rotate on the rotating shaft of the rotary stage, and the difference in the dynamic runout can cause a positional shift in the work. There is. The difference in the dynamic runout of the rotating shaft is defined as the rotating shaft when the rotating shaft is indexed at a certain angle, temporarily stopped, and rotated while repeating this, and the rotating shaft when the rotating shaft is continuously rotated at a constant speed. And that there is a difference. Therefore, in applications where both cross-section measurement and circumference measurement are performed and the circumference data and cross-section data are combined as data of the same surface shape, the positional displacement of the workpiece due to the difference in the rotation axis is included in some of the measurement data. If so, this could increase the measurement error.

  In view of the above, an object of the present invention is to make it possible to use a plurality of measurement results having different measurement directions, such as cross-section measurement and circumference measurement, without waste, to suppress a decrease in measurement accuracy, and to perform highly accurate shape measurement. It is to make.

  In order to solve the above problems, in the present invention, in a shape measuring method for scanning a probe following a surface of an object to be measured and measuring a shape of the object to be measured, the probe may be rotated around a predetermined rotation axis. A circumference measurement step of scanning the probe in a plurality of circumferential directions whose distances from the axis are different from each other, and acquiring the circumference measurement data of the object to be measured, and the probe in a plurality of radial directions crossing each other of the object to be measured. Scan, the diameter measurement step of acquiring the diameter measurement data of the object to be measured, and one of the circumference measurement data and the diameter measurement data, to correct the other error of the diameter measurement data and the circumference measurement data. And correcting the error of the uncorrected circumference measurement data or the diameter measurement data with the corrected diameter measurement data or the circumference measurement data. It was adopted formed.

  According to the above configuration, a plurality of measurement results such as a cross-section measurement and a circumference measurement having different measurement directions can be used without waste, a decrease in measurement accuracy can be suppressed, and a highly accurate shape measurement can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which showed the shape measuring apparatus which implemented this invention, and the structure of the production system using the same. FIG. 2 is a flowchart illustrating a flow of a main program according to the first embodiment in the shape measuring apparatus embodying the present invention. FIG. 9 is a flowchart illustrating a flow of a partial program according to a second embodiment in the shape measuring apparatus embodying the present invention. FIG. 9 is a flowchart illustrating a flow of a partial program according to a second embodiment in the shape measuring apparatus embodying the present invention. It is explanatory drawing which showed typically the trace situation of the to-be-measured object which performed several circumference measurement. It is explanatory drawing which showed typically the trace situation of the to-be-measured object which performed several cross-section measurement. FIG. 4 is an explanatory diagram showing a drift error generation factor that occurs in a plurality of circumference measurements. FIG. 5 is an explanatory diagram from a Z direction showing a drift error occurring in an object to be measured at the time of circumference measurement. FIG. 8 is an explanatory diagram from a Y direction showing a drift error occurring in a measured object at the time of circumference measurement. FIG. 4 is an explanatory diagram showing drift error occurrence factors that occur when performing a plurality of cross-section measurements. FIG. 5 is an explanatory diagram showing a drift error occurring in the object to be measured when performing a cross-section measurement from a Y direction. FIG. 5 is an explanatory diagram showing a drift error occurring in an object to be measured when performing a cross-sectional measurement from a bird's-eye view. FIG. 9 is an explanatory diagram showing a position error of the cross-sectional measurement data. It is explanatory drawing which showed the position error of circumference measurement data. It is explanatory drawing which showed typically the tracing situation of the to-be-measured object which performed several cross-section measurement with the general measuring device. It is explanatory drawing which showed typically the trace situation of the to-be-measured object which performed several circumference measurement with the general measuring device. It is explanatory drawing which showed typically the state which produced | generated the surface data by combining the circumference measurement and the cross-section measurement. FIG. 4 is an explanatory diagram schematically showing a difference between a dynamic run-out at the time of driving and a stop of a rotating shaft and an error of a work. FIG. 9 is a flowchart illustrating a flow of a main program according to a third embodiment in the shape measuring apparatus embodying the present invention. FIG. 13 is a flowchart illustrating a method of calculating a coordinate change amount according to a third embodiment in the shape measuring device embodying the present invention. FIG. 2 is an explanatory diagram showing a configuration of an aspheric lens as a work to be measured having a rotationally symmetric aspherical shape to which a three-dimensional shape measurement according to an embodiment of the present invention can be applied. FIG. 2 is an explanatory diagram showing a configuration of a control system used for three-dimensional shape measurement according to the embodiment of the present invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. The configuration described below is merely an example, and for example, a detailed configuration can be appropriately changed by those skilled in the art without departing from the spirit of the present invention. Also, the numerical values taken up in the present embodiment are reference numerical values and do not limit the present invention.

<First embodiment>
Next, an embodiment of a shape measuring device embodying the present invention will be described with reference to the drawings. FIG. 1 shows a configuration example of a shape measuring apparatus according to the present embodiment. In FIG. 1, an apparatus main body surface plate 101 constituting a base of the shape measuring apparatus 100 is installed on a vibration isolating table 102 which plays a role of not transmitting vibration to the apparatus main body and a gantry 103 which supports the entire apparatus main body.

  An X-axis stage guide 105 is supported on the apparatus main body platen 101 by two columnar frames 104. This form is a so-called portal shape. The X-axis stage guide 105 supports an X-axis stage slider 121 that can scan in the X-axis direction. The X-axis stage slider 121 constitutes a translation stage for linearly moving an object to be measured.

  A Z-axis stage guide 106 is mounted on the X-axis stage slider 121, and a Z-axis stage slider 107 that can move in the Z-axis direction is supported on the Z-axis stage guide 106.

  In FIG. 1, a contact probe 108 is mounted on the Z-axis stage slider 107 as probe means for scanning and measuring the object 109 to be measured. In the present embodiment, the contact type probe 108 is exemplified as the probe means. However, even when a non-contact type optical probe or the like is used as the probe means, the measurement technique described later can be implemented.

  The X-axis stage slider 121 has a Z-axis stage guide 106 mounted thereon, and is mounted on the X-axis stage guide 105, and can move in the X-axis direction. The Z-axis stage slider 107 is mounted on the Z-axis stage guide 106 and can move in the Z-axis direction. The contact probe 108 is mounted on the Z-axis slider 107, and is movable in the X-axis direction and the Z-axis direction by moving the X-axis stage slider 121 and driving the Z-axis slider 107. In the present embodiment, the X axis corresponds to the first stage axis, and the Z axis corresponds to the second stage axis.

  The X-axis stage guide 105 is provided with a drive mechanism for moving the X-axis stage slider 121 in the X-axis direction by a drive motor (not shown) such as a shaft motor. A drive motor (not shown) for driving the Z-axis stage slider 107 in the vertical direction in the drawing, that is, the Z-axis direction, for example, a linear motor is mounted on the Z-axis stage guide 106. Further, a scale (not shown) for measuring the position of the Z-axis stage slider 107 in the Z-axis direction is incorporated. This scale is composed of a laser scale, a linear encoder, and the like (the same applies to other axial scales described below).

  A first X-axis scale 114 for measuring the position of the X-axis stage slider 121 in the X-axis direction is supported on the apparatus main body platen 101 via an X-axis scale frame 113. The first X-axis scale 114 and the X-axis scale frame 113 supporting the first X-axis scale are arranged below the X-axis stage guide 105. Further, for example, in order to obtain measurement signals having different phases, a second X-axis scale 116 is supported by an X-axis scale frame 115 on the apparatus main body platen 101. The second X-axis scale frame 115 is installed on the apparatus main body platen 101, and supports the second X-axis scale 116. The second X-axis scale 116 and the X-axis scale frame 115 supporting the second X-axis scale are arranged below the X-axis stage guide 105.

  The first X-axis scale head 117 cooperates with the first X-axis scale 114 and outputs position data of the X-axis stage slider 121 in the X-axis direction. The first X-axis scale head 117 is mounted below the X-axis stage slider 121 via the first X-axis scale head frame 118.

  A similar structure is provided for a second scale head (not shown) that cooperates with the second X-axis scale frame 115. The second scale head (not shown) is installed on the apparatus main body platen 101 via the second X-axis scale head frame 120. The second X-axis scale head frame 120 is installed below the X-axis stage slider 121, and supports a second X-axis scale head (not shown).

  Although not shown in detail, the contact probe 108 includes, for example, a spherical contact, and, for example, a leaf spring as urging means for urging the contact in the direction of the measured object 109. Through this leaf spring, the contact pressure of the contact when the contact of the contact probe 108 comes into contact with the surface of the object to be measured 109 can be adjusted.

  For example, a displacement sensor (not shown) that measures the position of the contact with respect to the housing of the contact probe 108 is mounted on the contact. In the scanning measurement, the Z-axis position of the Z-axis stage 107 is controlled such that the contact of the contact probe 108 is brought into contact with the object 109 and the displacement of the displacement sensor indicates a constant value. The amount of deflection of the leaf spring can be controlled to be constant. With such a mechanism, the contact pressure of the contact with the DUT 109 in the scanning measurement can be controlled to be constant.

  In the configuration shown in FIG. 1, a tilt stage 110 for tilting the object to be measured 109 is provided, and the tilt stage 110 is mounted on two axes so as to tilt in a substantially orthogonal direction. The tilt stage 110 is arranged on the XY stage 111. With the XY stage 111, the DUT 109 and the tilt stage 110 can be translated in a direction substantially orthogonal to each other. Further, the XY stage 111 and the tilt stage 110 are installed on the θ rotation stage 112.

  The θ rotation stage 112 can perform a so-called indexing operation or a continuous rotational movement. The θ rotation stage 112 constitutes a rotation stage for rotating and moving an object to be measured about a predetermined rotation axis. The rotation angle position of the θ rotation stage 112 can be measured by an encoder (not shown).

  The measurement process of the shape measuring device 100 is controlled by a control device as shown in the lower part of FIG. 1, for example. The control system shown in the lower part of FIG. 1 is used for measuring the shape of an article having a rotationally symmetric aspherical shape, for example, a ground or polished aspherical optical element (for example, a lens or a mirror), and for shaping the aspherical optical element. It is used to measure the shape of the mold (die). The control system shown in the lower part of FIG. 1 determines the quality of these articles based on the results of the shape measurement and the processing apparatus 500 for grinding and polishing an aspherical lens or mirror, or a mold (die) thereof. Drive control can be performed. For example, based on the error data between the shape measurement data and the design shape data, pass / fail judgment is performed, and the drive of the processing device 500 is controlled to process these articles as objects to be measured into the design shape. Can be. That is, using the control system shown in the lower part of FIG. 1 and the processing apparatus 500, a production line for manufacturing or inspecting an article having a rotationally symmetric aspherical shape can be configured.

  FIG. 21 shows a cross-sectional shape of an aspherical lens in which one convex surface is formed as an aspherical surface, for example, as an example of an object to be rotated and has an aspherical shape whose shape can be measured by the shape measuring apparatus 100 of the present embodiment. . For example, in the case of an aspherical lens, as shown in the figure, the shape near the optical axis (lens center: one-dot chain line) is close to a spherical surface (two-dot chain line: radius R), and the shape of the peripheral portion deviates from the spherical surface. Some are parts.

  The surface shape of such an aspherical lens is defined by, for example, a height (Z) corresponding to a distance r from an optical axis (lens center: dashed line). Here, an aspheric lens having a convex surface formed of an aspheric surface is shown. However, the aspherical shape to be rotated that can be measured by the configuration of the present embodiment includes not only a convex surface but also a concave surface, and a shape such as a hyperboloid or a paraboloid used in a reflector. In addition, as a work that can be measured (or manufactured) in the present embodiment, a lens or a reflector having an aspherical shape formed by grinding, polishing, or the like, or a lens or a reflector having an aspherical shape is molded. Mold (mold) is conceivable.

  In the control system shown in the lower part of FIG. 1, the electrical equipment rack 122 includes a drive system of the shape measuring device 100. This drive system includes, for example, a driver for driving an X-axis stage slider 121 mounted on the X-axis stage guide 105 and a Z-axis stage slider 107 mounted on the Z-axis stage guide 106. The electrical rack 122 includes a driver for driving the two-axis tilt stage 110, the XY stage 111, and the θ rotation stage 112. Further, the electrical equipment rack 122 includes a board that reads data of the first and second X-axis scale positions output by the first X-axis scale head 117 and the second X-axis scale head. Further, this board can take in data output by a scale (not shown) incorporated in the Z-axis stage guide 106. Further, this board can take in data output by an encoder (not shown) of the θ rotation stage 112 and data output by a displacement sensor of the contact probe 108.

  The measurement control computer 123 controls the measurement processing of the shape measuring device 100 via the electrical equipment rack 122. The measurement control computer 123 has a program for instructing each of the drivers mounted on the electrical equipment rack 122 about the movement position and the like of the X-axis stage slider 121 and the Z-axis stage slider 107 mounted on the X-axis stage guide 105. The measurement control computer 123 has a program for instructing each driver mounted on the electrical rack 122 about the movement, rotation position, and the like of the tilt stage 110, the XY stage 111, and the θ rotation stage 112. In addition, the measurement control computer 123 has a program for loading data of each scale, encoder, and displacement sensor from the data loading board of the electrical equipment rack 122. Although FIG. 1 shows a configuration in which the measurement control computer 123 and the electrical equipment rack 122 are separate bodies, the measurement control computer 123 and the electrical equipment rack 122 may be configured as an integrated control device. .

  The data processing computer 124 has a man-machine interface function. The data processing computer 124 constitutes a user interface for taking in an operation input relating to a measurement condition parameter or the like by a user such as a system administrator or displaying (or printing) a shape measurement result. The shape measurement conditions managed by the data processing computer 124 include a measurement range, the number of measurements, a measurement speed, a measurement type, and a design value shape of the measured object. A data processing computer 124 processes these parameters to obtain measurement procedure data, and includes a measurement program to be sent to the measurement control computer 123 together with the measurement parameters. Further, the data processing computer 124 is equipped with a data acquisition program for acquiring the data of the scale of each axis and the data of the displacement sensor from the measurement control computer 123.

  Further, the data processing computer 124 has a shape data calculation program for calculating the surface shape of the workpiece 109 from each scale data, encoder data, and displacement sensor data taken in from the shape measurement device 100. Further, the data processing computer 124 has an error calculation program for calculating an error from a design value of the measured object 109 based on the calculated shape data of the measured object 109 and a design value shape of the measured object 109. Further, in the manufacturing system for an article having an aspherical shape, the data processing computer 124 is configured to judge the quality of the DUT 109 based on an error from a design value of the DUT 109 calculated by the error calculation program. It may be. Alternatively, the data processing computer 124 may be configured to be able to output to the processing apparatus 500 the calculated shape data of the measured object 109 and the error from the design value of the measured object 109 calculated by the error calculation program. Thus, the processing apparatus 500 can perform an operation of manufacturing an article for processing the object to be measured 109, for example, an aspheric lens or its mold (die) into a designed shape by numerical control.

  Further, the data processing computer 124 calculates, from the calculated shape data of the DUT 109, a shape position for calculating the three-dimensional position where the DUT 109 is placed with respect to the origin and coordinates of the apparatus or an arbitrary origin and coordinates. Equipped with a calculation program.

  Although the data processing computer 124 and the measurement control computer 123 are shown separately in FIG. 1, the data processing computer 124 and the measurement control computer 123 may be implemented as an integrated computer. Further, the data processing computer 124 and the measurement control computer 123 may be implemented as a computer integrated with the electrical equipment rack 122.

  Here, FIG. 22 shows a configuration that can be used as a control circuit of a data processing computer 124, a measurement control computer 123, an electrical rack 122, or a control device integrally formed by an arbitrary combination of these. The control device 1000 shown in FIG. 22 has a configuration including a CPU 1601 and each block disposed around the CPU 1601.

  The control device 1000 in FIG. 22 includes a CPU 1601 as main control means, a ROM 1602 as a storage device, and a RAM 1603. The ROM 1602 can store a control program of the CPU 1601 for realizing a control procedure described later, constant information, and the like. The RAM 1603 is used as a work area of the CPU 1601 when executing a control procedure described later.

  When the configuration in FIG. 22 is the data processing computer 124 or the measurement control computer 123, for example, a display 1608 and an operation unit 1609 are connected to the interface 1607 as user interface devices. The operation unit 1609 can be composed of, for example, a full keyboard and a pointing device, and constitutes a user interface for an operator.

  The control device 1000 in FIG. 22 includes a network interface 1605 as communication means for communicating via a network NW. The control device 1000 can configure a control unit of the data processing computer 124, the measurement control computer 123, and the electrical equipment rack 122. In that case, these 122, 123, and 124 or the processing device 500 can mutually communicate with other devices (1001A and 1001B in the figure) via the network interface 1605 to the network NW. For example, position data of each axis slider can be transmitted and received among the data processing computer 124, the measurement control computer 123, and the electrical equipment rack 122. In addition, pass / fail information, shape error data calculated by an error calculation program, and the like can be transmitted and received between the data processing computer 124 and the processing apparatus 500. The network interface 1605 can be configured by a communication standard based on wired communication such as IEEE 802.3 and wireless communication such as IEEE 802.11 and 802.15. However, any communication standard or protocol other than the above may be adopted as the communication standard or protocol of the network NW.

  Note that a control program of the CPU 1601 for implementing a control procedure to be described later can be stored in a storage unit such as an external storage device 1604 including an HDD or an SSD or a ROM 1602 (for example, an EEPROM area). In that case, a control program of the CPU 1601 for realizing a control procedure described later can be supplied to each of the above storage units via the network interface 1605 and updated to a new (another) program. Alternatively, a control program of the CPU 1601 for realizing a control procedure to be described later is supplied to each of the above storage units via various storage means such as a magnetic disk, an optical disk, and a flash memory, and a drive device therefor. Also, the contents can be updated. Various storage units and storage units in a state in which the control program of the CPU 1601 for implementing the above control procedure is stored constitute a computer-readable recording medium storing the control procedure of the present invention.

  The control device in FIG. 22 can be used as a control unit of the processing device 500. In that case, a drive system of the processing apparatus 500, for example, a driver circuit for a motor or a solenoid (not shown) is connected to the interface 1606.

  FIG. 2 shows a flow of a control procedure for realizing the surface shape measurement of the DUT 109 in the shape measuring apparatus of FIG. 1 embodying the present invention. The control procedure of FIG. 2 is implemented as a surface measurement program in the data processing computer 124 of FIG. In that case, in the configuration of FIG. 22, a specific program can be stored in the external storage device 1604 or the ROM 1602.

  Here, a surface measurement sequence executed by the data processing computer 124 will be described with reference to FIGS. In FIG. 2, step S201 is a circumference measurement process for measuring a plurality of circumferences of the surface of the measured object 109 in a substantially circumferential direction.

  In step S201, first, when the data processing computer 124 in FIG. 1 instructs the start of measurement, at this time, data such as design data, a measurement range, and a moving speed of the DUT 109 (for example, an aspherical lens) is obtained. I do. Subsequently, the moving position of the X-axis stage slider 121 and the moving position of the Z-axis stage slider 107 are sent to the measurement control computer 123 from the read various setting data and parameters. In response to this, the measurement control computer 123 instructs the X-axis driver of the electrical equipment rack 122 to move the X-axis stage slider 121 mounted on the X-axis stage guide 105 to the first X-axis position. Thereby, the shape measuring apparatus 100 moves the X-axis stage slider 121 to the first measured X coordinate of the measured object 109.

  When the X-axis movement is completed, the measurement control computer 123 instructs the Z-axis driver that drives the Z-axis stage slider 107 to descend. In response, the shape measuring device 100 causes the contact probe 108 to contact the surface of the object 109 to be measured. On the other hand, when the contact of the contact probe 108 comes into contact with the surface of the workpiece 109 due to the lowering of the Z-axis stage slider 107, the measurement control computer 123 detects this event via the output of a displacement sensor (not shown). Thereafter, the measurement control computer 123 or the electrical equipment rack 122 controls the Z-axis stage slider 107 so that the output from the displacement sensor (not shown) becomes constant.

  Next, the measurement control computer 123 outputs a command to the electrical equipment rack 122 to rotate the θ rotation stage 112 one round, and the electrical equipment rack 122 rotates the θ rotary stage 112 of the shape measuring device 100 one round. As a result, in the shape measuring apparatus 100, the θ-rotation stage 112 rotates while the contact probe 108 contacts the surface of the workpiece 109. Thus, a circumference measurement for scanning the surface of the object to be measured 109 by scanning measurement along the circumferential direction is performed. During this time, the Z-axis stage 107 is controlled so that the output from a displacement sensor (not shown) becomes substantially constant, and the contact state of the contact of the contact probe 108 with the object 109 is kept substantially constant.

  During the circumference measurement, the measurement control computer 123 reads the position data of the X-axis stage slider 121 with respect to the first X-axis scale 114 from the first X-axis scale head 117 via the electrical equipment rack 122. At the same time, the rotation angle is read from an encoder (not shown) of the θ rotation axis stage. At the same time, data from a Z-axis scale (not shown) and data taken from a displacement sensor are read into the measurement control computer 123 via the electrical equipment rack 122.

  The data of these scales and displacement sensors are read into the measurement control computer 123 via the scales, encoders and displacement sensor boards of the electrical equipment rack 122. When one circumference measurement is completed, the measurement control computer 123 outputs a command to the Z-axis driver of the electrical equipment rack 122 to raise the Z-axis, and raises the Z-axis stage 107. The circumference measurement for one round is performed as described above.

  The measurement control computer 123 moves the X-axis stage slider 121 mounted on the X-axis stage guide 105 to the second X-axis position in order to perform the next circumference, for example, the second (round) circumference measurement. A command is issued to the X-axis driver of the electrical equipment rack 122. Thereby, the shape measuring apparatus 100 moves the X-axis stage slider 121 to the second X coordinate of the measured object 109. Thereafter, the Z-axis stage slider 107 is driven in the same manner as described above, and the contact probe 108 is brought into contact with the surface of the object 109 to be measured. Subsequently, the second (circumferential) circumference measurement of the surface of the object 109 is performed by rotating the θ rotation stage 112 while the contact probe 108 is in contact with the surface of the object 109 in the same manner as described above. Can be.

  Step S201 is completed by repeating the above-described processing for the required number of times of the circumference measurement, whereby the measurement of the DUT 109 over a plurality of circumferences is completed. FIG. 5 schematically shows the trajectory of the measurement result when the circumference measurement is ideally performed. In the figure, four different circumferences are measured at different locations of the DUT 109 as indicated by arrows.

  FIG. 7 illustrates a drift error that may occur in the circumference measurement surface measurement data obtained in the circumference measurement in step S201 of FIG. FIG. 7 shows the positional relationship between the DUT 109 and the contact probe 108 in FIG. 1 in the form of a side view from the Y-axis direction. Note that the measurement technique of the present embodiment has a great effect particularly when the DUT 109 has a rotationally symmetric aspherical shape. However, the DUT 109 described below for explaining the measurement processing is described in FIG. Are shown as having a substantially spherical cross section for simplicity.

  In FIG. 7, C indicates a rotation center axis for rotating the object to be measured 109, A indicates an initial position (solid line) of the contact probe 108 viewed from C, and B indicates a position (dashed line) of the contact probe 108 after drift. ing. Such a drift of the position of the contact probe 108 in the X-axis direction is caused, for example, by a change in the size of a component of the mechanism due to a change over time of the environmental temperature.

  Here, an operation when the DUT 109 is rotated about C in FIG. 7 will be considered. In this case, scanning for scanning the surface of the object to be measured 109 as shown by the circles 801 (solid line) and 802 (dashed line) in FIG. 8 depending on the presence or absence of the drift of the position of the contact probe 108 in the X-axis direction. Have different radii. Thus, if the measurement control computer 123 recognizes that the circumference position of 801 (solid line) is being measured, for example, and if the measurement control computer 123 is actually measuring the circumference position of 802 (broken line), the figure is as follows. A measurement error occurs as indicated by the broken line 9. FIG. 9 shows the object to be measured 109 in the scanning state of FIG. 8 from the side.

  When the circumference scan of each circumference is performed in a state where there is a drift as shown in FIG. 8, the height of the measured object in the Z-axis direction shifted to the outer circumference side is lower than the measurement control computer 123 actually intends. A circumferential scan of the circumferential position 109 is performed. For this reason, in this example, the height in the Z-axis direction is measured lower than actual in each circumference, and is measured as having a shape indicated by a broken semicircle with respect to an actual shape indicated by a solid semicircle. I will. In the simplified drift example, the error occurs almost only in the Z direction, and the position error in the X and Y directions hardly occurs.

  Again in the control procedure of FIG. 2, following step S201, the cross-section measurement of step S202 is performed. Step S202 is a cross-section measurement (diameter measurement) process of measuring along the radial direction that passes through the approximate center of the surface of the object 109 and crosses each other. In this cross section measurement (diameter measurement), a plurality of cross sections are measured by determining the rotation angle of the object 109 to be measured. In this specification, “indexing” of a rotation angle refers to an operation of rotating the θ rotation stage 112 in units of a predetermined “index angle” in order to perform cross-sectional measurements in different radial directions. On the other hand, in the circumference measurement described above, the θ rotation stage 112 is continuously driven to rotate at a constant angular velocity, for example.

  In step S202 in FIG. 2, for example, when the data processing computer 124 in FIG. 1 instructs to start the measurement, the data such as the design data, the measurement range, and the moving speed of the DUT 109 are acquired. Regarding the design data of the device under test 109, if necessary data has already been acquired in step S201, the data is used. Subsequently, the movement position of the X-axis stage slider 121 and the movement position of the Z-axis stage slider 107 are output from the data processing computer 124 to the measurement control computer 123 based on the read various setting data and parameters. In response, the measurement control computer 123 instructs the X-axis driver of the electrical rack 122 to move the X-axis stage slider 121 mounted on the X-axis stage guide 105 to the X-axis measurement start position. As a result, the shape measuring apparatus 100 moves the X-axis stage slider 121 to the measurement start X coordinate of the workpiece 109. At the same time, the measurement control computer 123 instructs the θ rotation stage to rotate to the first index rotation position (index angle). Thereby, the shape measuring apparatus 100 rotates the θ rotation stage 112 to move the device under test 109 to the first rotation position (index angle).

  When the X-axis movement and the movement of the θ rotation stage are completed, the measurement control computer 123 instructs the Z-axis driver for driving the Z-axis stage slider 107 to descend. In response, the shape measuring device 100 causes the contact probe 108 to contact the surface of the object 109 to be measured. On the other hand, when the contact comes into contact with the surface of the workpiece 109 due to the lowering of the Z-axis stage slider 107, the measurement control computer 123 detects this event via the output of a displacement sensor (not shown).

  Next, the measurement control computer 123 instructs the X-axis driver of the electrical equipment rack 122 to move the X-axis stage slider 121 to the measurement end position in the X-axis direction. The slider 121 is moved in the X-axis direction. As a result, the contact probe 108 follows the object 109 in the radial direction and measures (cross-section measurement). That is, the X-axis stage slider 121 moves in the X-axis direction while the contact probe 108 contacts the surface of the object 109 to be measured. During this time, the measurement control computer 123 or the electrical equipment rack 122 controls the Z-axis stage slider 107 so that the output from a displacement sensor (not shown) becomes constant.

  During this cross-sectional measurement, the position data of the X-axis stage slider 121 with respect to the first X-axis scale 114 is read from the first X-axis scale head 117. At the same time, the position data of the X-axis stage slider 121 with respect to the second X-axis scale 116 is read from the second X-axis scale head. At the same time, data from a Z-axis scale (not shown) and data taken from a displacement sensor or the like are read. The index angle of the θ rotation stage 112 is detected via an encoder (not shown), and is read into the measurement control computer 123 via the electrical equipment rack 122.

  The data of these scales, encoders and displacement sensors are read into the measurement control computer 123 from the scales, encoders and displacement sensor boards of the electrical equipment rack 122. When the X-axis movement to the measurement end position is completed, the measurement control computer 123 outputs a command to the Z-axis driver of the electrical equipment rack 122 and raises the Z-axis stage 107 so that the measurement control computer 123 raises the Z-axis. . As described above, the cross-section of one diameter is measured. Data of each scale, encoder, and displacement sensor taken during the movement of the X-axis during the measurement of one section is transferred from the measurement control computer 123 to the data processing computer 124.

  With the above control, the data processing computer 124 can capture the movement trajectory coordinates of the contact probe 108 while the contact probe 108 moves while following the surface of the object 109 to be measured. Thus, the first (final) cross-sectional measurement is completed.

  Next, the measurement control computer 123 outputs a command to rotate the θ rotation stage 112 to the second indexing position to the θ rotation axis driver of the electrical equipment rack 122 in order to perform the second (final) cross section measurement. As a result, the shape measuring apparatus 100 rotates and drives the θ rotation stage 112 to move the θ rotation stage 112 to the second (real) θ rotation indexing position. Thereafter, the Z-axis stage slider 107 is driven in the same manner as the first (final) one, and the contact probe 108 is brought into contact with the surface of the object 109 to be measured. Subsequently, by moving the X-axis stage slider 121 while similarly bringing the contact probe 108 into contact with the surface of the object to be measured 109, the second (final) cross-sectional measurement of the surface of the object to be measured 109 can be performed. it can.

  By repeating the above process for the required number of times of the cross-section measurement, step S202 in FIG. 2 is completed, and the measurement of the object to be measured 109 on a plurality of cross-sections is completed. FIG. 6 schematically shows the locus of the measurement result when the circumference measurement is ideally performed. In the drawing, four positions on different diameters of the DUT 109 are measured in cross section as indicated by arrows.

  FIG. 10 illustrates a drift error that may occur in the cross-section measurement plane measurement data obtained in the cross-section measurement in step S202 in FIG. FIG. 10 shows the positional relationship between the DUT 109 and the contact probe 108 in FIG.

  In FIG. 10, C indicates the center coordinates of the object 109 to be measured, A indicates the initial position of the contact probe 108 (solid line) viewed from C, and B indicates the position of the contact probe 108 after drift (dashed line). As described above, such a drift in the position of the contact probe 108 in the X-axis direction is caused by a change in the dimensions of the components of the mechanism due to, for example, changes over time in the environmental temperature.

  In FIG. 10, when the cross section measurement is performed when the drift of the contact probe 108 occurs as shown in B, the measured object 109 relatively moves in the X direction around the C axis. Is measured as if the device under test 109 has moved in the X direction. FIG. 11 schematically shows a state where the cross-section measurement is repeated for four lines, and the object to be measured 109 is measured with its position in the X direction shifted sequentially. FIG. 12 is a perspective view showing an example of trace positions on the object to be measured 109 when four cross-sections of FIG. 11 are measured at four index angles of the object to be measured 109. As shown in FIG. 12, each cross-sectional data at four index angles is measured as if the data has moved in the X and Y directions due to drift errors. Since the time during the cross-section movement is sufficiently short, the drift error in the Z-direction of each cross-section data is extremely small, and it cannot be assumed that the drift error hardly occurs.

  As described above, when step S201 and step S202 are completed, two types of surface measurement, that is, the circumference measurement and the cross-section measurement for the object to be measured 109 are completed. Although FIG. 2 is configured to perform the circumference measurement and then the cross-section measurement as in steps S201 and S202, the order of steps S201 and S202 may be reversed.

  In the present embodiment, as described below, the error component between the circumference measurement surface data obtained in step S201 of FIG. 2 and the cross-section measurement data (diameter measurement data) obtained in step S202 is corrected, and Then, surface data (shape data) 109 is generated. Step S203 in FIG. 2 is a process for calculating the positional deviation of the circumference measurement surface data measured in step S201, and in this step S203, a fitting process is performed.

  The fitting process compares the surface shape measurement data of the object 109 with the design shape data of the object 109, and calculates the position movement amount of the surface shape data of the object 109 at which the difference is minimized. It is. Generally, the least square method is used for the correction operation for the fitting process. For example, from a coordinate transformation formula that translates and tilts the surface shape measurement data, the least square method is used to convert the surface shape measurement data and the surface shape design data to minimize the sum of squares of the surface shape data. The position amount and the tilt movement position amount can be obtained. The circumference measurement surface data of the DUT 109 whose position error has been corrected by such fitting processing is obtained.

  Next, in step S204, a process of correcting an error generated due to, for example, a drift is performed using the cross-section measurement data obtained in step S202 and the circumference measurement surface data obtained in step S203. Here, when FS is the circumference measurement plane data and FDn is the n-th data of the cross-section measurement plane data, the position errors dx and dy in the xy translation direction of each cross-section where En of the following equation (1) is minimized; The inclination errors wx and wy of each section are obtained. Also in this case, for example, the least square method can be used for the correction calculation.

そして、式（１）によるＥｎが最小となるｄｘ、ｄｙ、ｗｘ、ｗｙを求める処理を断面測定割り出しの回数分、ｎ回行う。図１３は、補正すべき断面データ１３０１と、その補正量に相当する、上記の位置誤差ｄｘ、ｄｙおよび傾き誤差ｗｘ、ｗｙを示している。

Then, a process for obtaining dx, dy, wx, wy that minimizes En according to the equation (1) is performed n times for the number of times of the cross-section measurement index. FIG. 13 shows the cross-sectional data 1301 to be corrected, and the position errors dx and dy and the tilt errors wx and wy corresponding to the correction amount.

  There is very little asymmetric component, that is, drift error in the XY directions in the circumference measurement plane data in step S201. For this reason, the XY direction position error caused by the drift, for example, included in the cross-sectional measurement data in step S202 can be accurately obtained by the above processing.

  Next, in step S205, shape (plane) data is generated from the cross-sectional measurement data for which the position error due to the drift has been obtained in step S204. In step S205, the coordinates FDn of each section are converted using the position errors dx and dy and the inclination errors wx and wy of each section. Thus, shape (plane) data in which the position error is corrected can be generated from each cross-sectional data. In this way, it is possible to obtain shape (surface) data based on the cross-section measurement data whose drift has been corrected by the calculation in step S205.

  Subsequently, in step S206, an error due to, for example, drift of the circumference measurement data measured in step S201 is corrected using the cross-section measurement plane data in which the position error has been corrected in step S205. Here, for example, when FSm is the m-th data of the circumference measurement plane data, FDf is the cross-section measurement plane data after drift correction, and dz is the position error of each circumference in the Z direction (height direction), the following equation ( An error dz that minimizes Em in 2) is obtained.

この場合も、誤差ｄｚを求めるには例えば最小二乗法を利用できる。この式（２）のＥｍが最小となる誤差ｄｚを求める処理を周測定の回数分、ｍ回、行って、各断面測定データのＺ方向の位置誤差ｄｚを求めることができる。図１４は、補正すべき周データ１４０１と、その補正量に相当する、上記のＺ方向に関する位置誤差ｄｚの方向を示している。さらに、各周測定データＦＳｍを各周の位置誤差ｄｚで座標変換することにより、位置誤差を補正した周測定データに変換することができる。

Also in this case, for example, the least square method can be used to obtain the error dz. The process of finding the error dz that minimizes Em in the equation (2) is performed m times, the number of times of the circumference measurement, and the position error dz in the Z direction of each section measurement data can be found. FIG. 14 shows the circumference data 1401 to be corrected and the direction of the position error dz in the Z direction corresponding to the correction amount. Further, by performing coordinate conversion of each circumference measurement data FSm with the position error dz of each circumference, the circumference measurement data FSm can be converted into circumference measurement data in which the position error is corrected.

  Since there is very little error in the Z direction in the cross-section measurement data obtained in step S202, the position error dz due to the drift of the circumference measurement surface data can be accurately corrected by the processing in step S206.

  As described above, according to the measurement processing of FIG. 2, drift errors of the circumference measurement and the cross-section measurement are removed from each other, surface (shape) data obtained by the corrected circumference measurement and the cross-section measurement are acquired, and the corrected circumference measurement is performed. And the cross-section measurement can be combined to generate surface (shape) data with high accuracy. In the measurement processing of the present embodiment, the measurement data obtained in the circumference measurement and the cross-section measurement can be mutually accurately corrected by utilizing the fact that the measurement error acting on the surface measurement and the cross-section measurement are different. That is, the present embodiment utilizes the point that the asymmetric component, that is, the drift error in the XY directions is very small in the surface measurement, while the error in the Z direction is very small in the cross-sectional measurement.

  According to the measurement processing of the present embodiment, the surface (shape) data obtained by the circumference measurement and the cross-section measurement can be used without waste, and is used only for the purpose of correction or calibration as in the related art. It is not necessary to execute the measurement sequence. Therefore, according to the present embodiment, a plurality of measurement results having different measurement directions, such as a cross-section measurement and a circumference measurement, can be used without waste. And high-density shape measurement can be performed.

  In the processing example described above, the error of the cross-section (surface) measurement data is corrected by the circumference measurement data (first correction step), and the circumference measurement data is corrected by the corrected cross-section (surface) measurement data. (Second Correction Step) The processing order has been exemplified. However, the measurement data used for correction may be reversed.

  For example, after fitting the cross-section (diameter) measurement data, the error of the circumference measurement data is corrected by the cross-section (diameter) measurement data (first correction step), and the cross-section (surface) measurement is performed by the corrected circumference measurement data. A processing order for correcting data (second correction step) may be adopted. That is, one of the circumference measurement data and the cross-section measurement data corrects the other error of the cross-section (diameter) data or the circumference measurement data. Then, the error of the uncorrected circumference measurement data or cross-section (diameter) data is corrected based on the corrected cross-section (diameter) data or circumference measurement data. Regardless of the processing order, the errors acting on the circumference measurement data and the cross-section (surface) measurement data are different from each other, so that the same operation and effect as described above can be expected.

<Embodiment 2>
In the second embodiment, in the measurement processing of FIG. 2, processing contents of different calculation processing that can be performed in steps S <b> 204 and S <b> 206 will be described. The hardware configuration and the software configuration other than steps S204 and S206 in FIG. 2 are the same as in the first embodiment.

  FIG. 3 shows the arithmetic processing of this embodiment executed as step S204 of FIG. 2, and FIG. 4 shows the arithmetic processing of this embodiment executed as step S206 of FIG. 2, respectively. Steps S201 to S203 in FIG. 2 are performed in the same manner as in the first embodiment.

  In the processing procedure of FIG. 3 executed as step S204 of FIG. 2, first, in step S301, a function conversion is performed in which the circumference data measured in step S201 and the cross-sectional data measured in step S202 are replaced with functions. Here, for example, the circumference data can be replaced with a Zernike function, and the cross-section data can be replaced with a design value function of the DUT 109. In this case, both may be replaced, or a method of replacing only one of them may be adopted.

  This function can be replaced by a least-squares method in which an equation for the difference from the measured data is created using the coefficient of the function as a variable, and a variable that minimizes the sum of squares of the equation can be used.

  Next, in step S302, a process of correcting the drift of the cross-sectional data after the function conversion is performed using the circumference data converted into a function in step S301. Here, assuming that the circumference measurement plane data obtained by converting FSk into a function and the FDkn becomes the nth data of the cross-section measurement plane data obtained by a function, the position errors dx and dy of the respective cross sections where Ekn in the following equation (3) is minimized. And the inclination errors wx and wy of each section are obtained. Also in this case, for example, the least square method can be used.

そして、式（３）によるＥｋｎが最小となる上記のｄｘ、ｄｙ、ｗｘ、ｗｙを求める処理を断面測定割り出しの回数分、ｎ回行う。

Then, the processing for obtaining the above dx, dy, wx, wy that minimizes Ekn by the equation (3) is performed n times for the number of times of the section measurement index.

  As described above, the circumference measurement plane data in step S201 has very little asymmetric component, that is, drift error in the XY directions. For this reason, the XY direction position error caused by the drift, for example, included in the cross-sectional measurement data in step S202 can be accurately obtained by the above processing.

  Subsequently, in step S303, surface data is generated from the cross-sectional measurement data in which the position error caused by the drift in step S302 has been corrected. In this step S303, the coordinates FDkn of each section are converted according to the position errors dx, dy and the inclination errors wx, wy of each section, and converted into section data in which the position errors have been corrected. By the calculation in the above step S303, it is possible to obtain position error data of each cross-section measurement data capable of correcting an error caused by the drift.

  Subsequently, the process of step S205 in FIG. 2 is executed as in the first embodiment. In step S205, surface data is generated from the cross-sectional measurement data in which the position error due to the drift has been corrected in steps S301 to S303 in FIG. In this step S205, the coordinates FDkn of each section are converted based on the position errors dx and dy and the tilt errors wx and wy of each section, and the data FDkn is converted into section data in which the position error is corrected. In this way, it is possible to obtain shape (surface) data based on the cross-section measurement data whose drift has been corrected by the calculation in step S205.

  Subsequently, the processing procedure of FIG. 4 is executed as step S206 of FIG. Here, first, in step S401, for example, an error caused by drift is corrected using the circumference measurement data measured in step S201 and the cross-section measurement surface data in which the position error has been corrected in step S205.

  In step S401, for example, assuming that the m-th data of the circumference measurement plane data obtained by converting the function of FSkm and the FDkf is the cross-section measurement plane data obtained by performing function correction after drift correction, Ekm of the following equation (4) is minimized. Find dz. Also in this case, for example, the least square method can be used.

そして、式（４）によるＥｋｍが最小となるｄｚを求める処理を周測定の回数分、ｍ回行う。これにより、各断面測定データのＺ方向位置誤差ｄｚを求めることができる。

Then, the processing for obtaining dz at which Ekm is minimized by the equation (4) is performed m times for the number of circumference measurements. Thereby, the Z-direction position error dz of each section measurement data can be obtained.

  Further, in step S402, each circumference measurement data FSkm is subjected to coordinate conversion using the position error dz of each circumference, and is converted into circumference measurement data in which the position error is corrected.

  As described above, there is very little error in the Z direction in the cross-sectional measurement data in step S202. Therefore, the processing in steps S401 and S402 accurately corrects the position error due to the drift of the circumference measurement surface data in step S201. can do.

  FIG. 17 is an explanatory diagram schematically showing a state in which surface data is generated by combining the circumference measurement and the cross-section measurement as described above. The figure shows a process of measuring the shape of the object to be measured from the circumferential data and the cross-sectional data obtained by performing four circumferential measurements and four radial cross-sectional measurements as indicated by arrows.

  According to the above-described measurement processing shown in FIGS. 2, 3, and 4, drift errors in the circumference and cross-section measurement are removed from each other, and corrected surface (shape) data is obtained by the circumference and cross-section measurement. The surface (shape) data can be generated with high accuracy by combining the circumference measurement and the cross-section measurement. In the measurement processing of the present embodiment, the measurement data obtained in the circumference measurement and the cross-section measurement can be mutually accurately corrected by utilizing the fact that the measurement error acting on the surface measurement and the cross-section measurement are different. That is, the present embodiment utilizes the point that the asymmetric component, that is, the drift error in the XY directions is very small in the surface measurement, while the error in the Z direction is very small in the cross-sectional measurement.

  According to the measurement processing of the present embodiment, the surface (shape) data obtained by the circumference measurement and the cross-section measurement can be used without waste, and is used only for the purpose of correction or calibration as in the related art. It is not necessary to execute the measurement sequence. Therefore, according to the present embodiment, a plurality of measurement results having different measurement directions, such as a cross-section measurement and a circumference measurement, can be used without waste. And high-density shape measurement can be performed.

  In the present embodiment, the measurement process is performed using the data obtained by performing the function conversion (S301 in FIG. 3). Therefore, even when an irregular error is present near the intersection between the circumference measurement and the cross-section (diameter) measurement, the possibility that the measurement result is affected can be reduced.

<Embodiment 3>
In the present embodiment, a shape measurement process taking into account a dynamic error of the rotation axis for indexing the circumference measurement and the cross-section measurement will be described. The hardware configuration of the shape measuring device 100 or the measurement (manufacturing) system in the present embodiment is the same as that in FIG. In the present embodiment, the shape measurement processing as shown in FIGS. 19 and 20 is performed by the data processing computer 124 of FIG.

  19, step S2001 is a circumference measurement process similar to step S201 in FIG. 2, and step S2002 is a cross-section measurement process similar to step S202 in FIG. In the present embodiment, step S2003 is performed following steps S2001 and S2002. In step S2003, coordinate conversion is performed for each cross-sectional measurement result by the amount of the dynamic shake difference.

  FIGS. 18A to 18C schematically show a work position shift caused by a difference between a dynamic fluctuation and a run-out when the work rotating shaft is stopped and when it is driven. In FIG. 18A, reference numeral 1901 denotes a rotating shaft, 1902 denotes a rotary table when stopped, and 1903 denotes a work position when stopped. Also, in FIG. 18B, reference numerals 1904 and 1905 denote, for example, a 0-degree phase rotation table and a work position during rotation driving, respectively. In FIG. 18C, reference numerals 1906 and 1907 denote a rotating table and a work position, for example, having a phase of 180 degrees during driving. 18A to 18C, the angle difference １９０ between 1903, 1904, and 1905 corresponds to a dynamic shift of the work position.

  The error of the dynamic rotation axis as described above can be corrected by performing a measurement process including coordinate conversion as shown in FIG.

  In step S2101 in FIG. 20, a rotationally symmetric and aspherical work is set on the θ rotation stage 112. It is preferable that the shape of the work has a sufficiently small error with respect to the known design shape. In step S2102, a plurality of cross-section measurements are performed with indexing of the rotation axis. The control of the cross-section measurement at this time may be the same as step S202 in FIG. In order to calculate the coordinate transformation amount more accurately, measures such as measuring as many cross sections as possible, and performing averaging processing by measuring the same cross section a plurality of times can be taken.

  Subsequently, in step S2103, the results of the plurality of cross-section measurements are processed as surface data, and the position of the aspherical workpiece in the XYZ orthogonal coordinate system is calculated. At this time, for example, as described in Patent Literature 3, each measurement section is rotated at an index angle obtained by measuring the section about a known rotation axis in advance, and all of them are coordinate-transformed back to the 0-degree azimuth. Thus, the position of the aspherical workpiece in the XYZ orthogonal coordinate system can be calculated.

  Here, assuming that FA is the design shape (or known shape) data and FD is the measurement data of a plurality of cross sections when the FD is returned to the 0-degree azimuth, the translation in the 0-degree azimuth at which the ED of the following equation (5) is minimum An installation error, dxD, dyD, and a work inclination error wxD, wyD at the 0-degree azimuth are determined. This calculation can be performed by, for example, the least squares method.

  Subsequently, in step S2104 in FIG. 20, a plurality of circumference measurements are performed. The control of this circumference measurement may be the same as step S201 in FIG. In order to calculate the coordinate transformation amount more accurately, measures such as measuring as many circumferences as possible and performing averaging processing by measuring the same circumference a plurality of times can be taken. Note that, between steps S2102 and S2104, it is not assumed that the installation position of the work on the stage is changed, such as when the work is attached or detached.

  Next, in step S2105, the result of the multiple circumference measurement is processed as surface data, and the position of the aspherical workpiece in the XYZ orthogonal coordinate system is calculated. The result of measuring the circumference around a known rotation axis in advance is converted from the RΘZ coordinate system to the XYZ orthogonal coordinate system, and a measurement result based on the 0-degree azimuth is obtained.

  Here, FA is the design shape (or known shape) data, and FS is the measurement data of a plurality of rounds. Then, the translational installation errors dxS, dyS at the 0-degree azimuth at which ES of the following equation (6) is minimum, and the work inclination errors wxS, wyS at the 0-degree azimuth are obtained. This calculation can be performed by, for example, the least squares method.

  Next, in step S2106, a difference between dxD, dyD, wxD, wyD calculated by the cross-sectional measurement and dxS, dyS, wxS, wyS calculated by the circumference measurement is calculated. The calculated difference, that is, the coordinate change amount is stored in the data processing computer 124 as the coordinate change amount of the cross-section measurement and the circumference measurement. The coordinate change amount data is stored in, for example, the RAM 1603 or the external storage device 1604. The calculation of the coordinate change amount in FIG. 20 may be performed each time the shape is measured, or may be performed at the time of starting the apparatus or at the time of periodic calibration. The coordinate conversion amount obtained in step S2003 may be obtained as a conversion amount from the cross-section measurement to the circumference measurement position, or may be obtained as a conversion amount for performing an inverse conversion from the circumference measurement to the cross-section measurement position. By performing coordinate transformation for adding the coordinate change amount thus acquired to the circumference measurement data or the diameter measurement data, corrected shape measurement data can be obtained.

  As described above, according to the present embodiment, by the measurement processing shown in FIGS. 19 and 20, the circumference measurement and the cross-section measurement in which the difference in the dynamic shaft runout between the circumference measurement and the cross-section measurement is removed are combined. Plane data can be generated. That is, according to the present embodiment, the shape measuring apparatus shown in FIGS. 1, 2, 3, 4, and 20 allows an optical element typified by an aspherical surface, a spherical surface, or the like of an object to be measured, Alternatively, it is possible to accurately determine the surface shape of a similar structure. The present invention supplies a program for realizing one or more functions of the above-described embodiments to a system or an apparatus via a network or a storage medium, and one or more processors in a computer of the system or the apparatus read and execute the program. This processing can be realized. Further, it can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

  Reference Signs List 100: Shape measuring device, 102: Anti-vibration table, 103: Stand, 104: Frame, 105: X-axis stage guide, 106: Z-axis stage guide, 107: Z-axis stage slider, 108: Contact probe, 109 ... Measurement object, 110: tilt stage, 111: XY stage, 112: θ rotation stage, 122: electrical equipment rack, 123: measurement control computer, 124: data processing computer.

Claims (20)

In the shape measuring method for scanning the probe following the surface of the object to be measured and measuring the shape of the object to be measured,
A circumference measurement step of scanning the probe in a plurality of circumference directions whose distances from the rotation axis are different from each other around a predetermined rotation axis, and obtaining circumference measurement data of the measured object,
A diameter measurement step of scanning the probe in a plurality of radial directions intersecting each other of the object to be measured, and acquiring diameter measurement data of the object to be measured,
Either the circumference measurement data or the diameter measurement data corrects the other error of the diameter measurement data and the circumference measurement data, and is not corrected by the corrected diameter measurement data or the circumference measurement data. A correcting step of correcting an error between the circumference measurement data or the diameter measurement data. In the shape measuring method for scanning the probe following the surface of the object to be measured and measuring the shape of the object to be measured,
A circumference measurement step of scanning the probe in a plurality of circumference directions whose distances from the rotation axis are different from each other around a predetermined rotation axis, and obtaining circumference measurement data of the measured object,
A diameter measurement step of scanning the probe in a plurality of radial directions intersecting each other of the object to be measured, and acquiring diameter measurement data of the object to be measured,
A first correction step of correcting an error of the diameter measurement data by the circumference measurement data;
A second correction step of correcting an error in the circumference measurement data using the corrected diameter measurement data corrected in the first correction step.   3. The shape measurement method according to claim 2, wherein, before the first or second correction step, at least one of the circumference measurement data and the diameter measurement data is function-converted, and the function-converted circumference measurement data and And / or a shape measurement method for executing the first or second correction step using the diameter measurement data.   4. The shape measuring method according to claim 2, wherein the correction in the first or second correction step is performed by a correction operation using a least squares method.   5. The shape measuring method according to claim 2, wherein, in the first correction step, a position error in a translation direction of the diameter measurement data and a tilt error of each cross section are determined by the circumference measurement data. 6. Shape measurement method to be corrected.   The shape measuring method according to any one of claims 2 to 5, wherein in the second correction step, a position error in the height direction of the circumference measurement data is corrected by the corrected diameter measurement data. Measuring method.   7. The shape measurement method according to claim 2, wherein the circumference measurement data is compared with the circumference measurement data and the design shape data of the object to be measured before the first correction step. Shape measurement method to be corrected by fitting processing.   The shape measuring method according to claim 1, wherein the object has an aspherical shape to be rotated.   The shape measuring method according to claim 1, wherein the object to be measured is a rotationally symmetric aspherical optical element or a mold used for molding a rotationally symmetric aspherical optical element. In the shape measuring method for scanning the probe following the surface of the object to be measured and measuring the shape of the object to be measured,
A circumference measurement step of scanning the probe in a plurality of circumference directions whose distances from the rotation axis are different from each other around a predetermined rotation axis, and obtaining circumference measurement data of the measured object,
A diameter measurement step of scanning the probe in a plurality of radial directions intersecting each other of the object to be measured, and acquiring diameter measurement data of the object to be measured,
From the circumference measurement data and the diameter measurement data, a calculation step of calculating a coordinate change amount caused by the fluctuation of the rotation axis,
A coordinate conversion step of adding the coordinate change amount to the circumference measurement data or the diameter measurement data.   11. The shape measuring method according to claim 10, wherein the coordinate change amount is a difference between the circumference measurement data obtained in the circumference measurement step and the diameter measurement data obtained in the diameter measurement step.   A translation stage for linearly moving the object to be measured, a rotary stage for rotating and moving the object to be measured around a rotation axis, a probe for scanning and measuring the object to be measured, and controlling a shape measurement of the object to be measured. A control program for executing each step of the shape measuring method according to any one of claims 1 to 11 by causing a computer constituting the control device of the shape measuring device including the control device to read the computer.   A computer-readable recording medium storing the control program according to claim 12. A translation stage for linearly moving the object to be measured, a rotary stage for rotating and moving the object to be measured around a rotation axis, a probe for scanning and measuring the object to be measured, and controlling a shape measurement of the object to be measured. And a control device, comprising: a shape measuring device for measuring the shape of the object to be measured,
The control device moves the probe to a plurality of circumferential positions around the rotation axis by the translation stage, causes the probe to follow and measure the object to be measured at each circumferential position, and obtains a plurality of circumferential measurement data. A circumference measurement step of obtaining the rotation stage, rotating the rotation stage at a plurality of index angles around the rotation axis, causing the probe to trace the object under each index angle, and measuring a plurality of diameter measurement data. Performing a diameter measuring step to obtain
The control device corrects the other error of the diameter measurement data and the circumference measurement data by one of the circumference measurement data and the diameter measurement data, and corrects the diameter measurement data or the circumference measurement data. A shape measuring apparatus for correcting an error of the circumference measurement data or the diameter measurement data that has not been corrected. A translation stage for linearly moving the object to be measured, a rotary stage for rotating and moving the object to be measured around a rotation axis, a probe for scanning and measuring the object to be measured, and controlling a shape measurement of the object to be measured. And a control device, comprising: a shape measuring device for measuring the shape of the object to be measured,
The control device moves the probe to a plurality of circumferential positions around the rotation axis by the translation stage, causes the probe to follow and measure the object to be measured at each circumferential position, and obtains a plurality of circumferential measurement data. A circumference measurement step of obtaining the rotation stage, rotating the rotation stage at a plurality of index angles around the rotation axis, causing the probe to trace the object under each index angle, and measuring a plurality of diameter measurement data. Performing a diameter measuring step to obtain
A shape measuring device, wherein the control device corrects an error in the diameter measurement data with the circumference measurement data, and corrects the circumference measurement data with the corrected diameter measurement data. A translation stage for linearly moving the object to be measured, a rotary stage for rotating and moving the object to be measured around a rotation axis, a probe for scanning and measuring the object to be measured, and controlling a shape measurement of the object to be measured. And a control device, comprising: a shape measuring device for measuring the shape of the object to be measured,
The control device moves the probe to a plurality of circumferential positions around the rotation axis by the translation stage, causes the probe to follow and measure the object to be measured at each circumferential position, and obtains a plurality of circumferential measurement data. A circumference measurement step of obtaining the rotation stage, rotating the rotation stage at a plurality of index angles around the rotation axis, causing the probe to trace the object under each index angle, and measuring a plurality of diameter measurement data. Performing a diameter measuring step to obtain
The control device calculates a coordinate change amount due to the fluctuation of the rotation axis from the circumference measurement data and the diameter measurement data, and adds the coordinate change amount to the circumference measurement data or the diameter measurement data. Shape measuring device.   17. An inspection method for inspecting an article using the shape measuring apparatus according to any one of claims 14 to 16, wherein the shape measurement result obtained by measuring the shape of the article as the object to be measured by the shape measuring apparatus; An inspection method for inspecting the article based on error data with respect to the design shape data.   18. A manufacturing method for inspecting an article by the inspection method according to claim 17 and manufacturing the article, wherein drive control of a processing apparatus for processing the article based on error data between the shape measurement result and the design shape data of the article. Manufacturing method of articles to be made.   19. The method for manufacturing an article according to claim 18, wherein the article to be measured as the object to be measured is a rotationally symmetric aspheric optical element or a mold used for molding a rotationally symmetric aspheric optical element. .   A shape measuring device according to any one of claims 14 to 16, and a processing device for an article whose shape is to be measured as the object to be measured, wherein the shape is measured by the shape measuring device as the object to be measured. An article manufacturing system in which the processing device is driven and controlled based on error data between a measured shape measurement result and design article shape data.

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