JP2001324311A - Three-dimensional shape measuring machine and its measuring method - Google Patents

Abstract

(57) [Problem] To accurately measure the shape of both sides of an object to be measured, without inverting the object or using interference, while holding the object to be measured in the same horizontal direction as used. Provided is a three-dimensional shape measuring instrument having a simple configuration and a measuring method therefor. An upper surface optical probe that scans an upper surface of an object to be measured and a lower surface optical probe that scans a lower surface of the object to be measured include an upper surface R stage and a lower surface R stage in a horizontal R axis direction, and a vertical direction. The object to be measured is mounted on the upper and lower Z-stages in the Z-axis direction, respectively, and the object to be measured is mounted horizontally on the θ-stage in the θ-axis direction, which is the rotation component of the Z-axis. A position detecting means for detecting a scanning position and a θ-axis rotation angle of the object to be measured, and a movement error detecting means for detecting a movement error caused by scanning of the optical probe or rotation of the object to be measured, and Calculating the shape of the measured object from the detection result of the motion error detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional shape measuring machine for measuring the surface shape of an optical component, a mold or the like with high accuracy and a measuring method therefor.

[0002]

2. Description of the Related Art Conventionally, it has been widely known to use a three-dimensional shape measuring machine to measure the surface shape of an object such as an optical component or a mold with high accuracy. Generally, a three-dimensional shape measuring instrument moves a probe of a contact type or a non-contact type close to an object to be measured, and controls a probe position so that the two have a substantially constant distance or a substantially constant force relationship. The shape is measured by scanning the object to be measured.

As an example of such a three-dimensional shape measuring instrument, an ultra-high precision three-dimensional shape measuring instrument disclosed in Japanese Patent Application Laid-Open No. 4-299206 will be described with reference to FIG. In the figure, reference numeral 27 denotes an X stage, on which a Y stage 28 and a Z stage 4 are further formed. X reference mirrors 2 on YZ-XZ-XY planes which are on planes perpendicular to the XYZ axes, respectively
9, a Y reference mirror 30, and a Z reference mirror 5 are arranged. On the Z stage 4, an optical probe 26 for detecting a distance Z1 between the DUT 1 and a specific point on the Z stage 4, a distance Z2 between the specific point on the Z stage 4 and a fixed position Z reference mirror 5
Means 9c for detecting the distance X, a specific point on the Z stage 4 and a distance X between the fixed position X reference mirror 29, and a distance Y between the specific point on the Z stage 4 and the position fixed Y reference mirror 30. Measuring means 9k (Z stage 4
(Not shown in the figure).

Accordingly, the optical probe 26 installed on the Z stage 4 can move in the XYZ axis directions, and the three-dimensional coordinates at that time are (X, Y, Z1 and Z2).
Z) calculated from the following. Optical probe 2
6 is scanned over the entire surface of the DUT 1 and the three-dimensional coordinates at that time are detected, whereby the three-dimensional shape of the DUT can be measured.

As another conventional example, Japanese Patent No.
The surface shape measuring device disclosed in Japanese Patent No. 71479 will be described with reference to FIG. In FIG. 1, a Fizeau interferometer is used to measure both surfaces 1a and 1b while the DUT 1 is held in the same horizontal direction as that in use.

The light beam emitted from the laser light source 15 is divided into a lens 31, a half mirror 32 and a collimator lens 3.
Through 3, the light goes to the reflection mirror 34 a. The reflecting mirror 34a is variable in and out of the optical path. When the reflecting mirror 34a enters the optical path, the light beam is bent in the vertical direction by the reflecting mirror 34a, is reflected by the reflecting mirrors 34b and 34c, and then enters the reference lens 35. . Here, a part of the light beam is reflected by the reference surface 35a of the reference lens 35, and the other light is transmitted. The light beam transmitted through the reference lens 35 and incident on the DUT 1 is reflected by the surface 1 a of the DUT 1 to be a measurement lightwave. The light wave reflected by the reference surface 35a of the reference lens 35 becomes a reference light wave. The reference lightwave and the measurement lightwave overlap again and interfere with each other, and return along the optical path from which they came.
After the optical path is bent in the vertical direction by the reflection mirrors 34c, 34b, and 34a, the light enters the half mirror 32 via the collimator lens 33. Here, the interference light wave is bent in the vertical direction, and is detected by the interference detection means 38 such as a CCD camera via the condenser lens 37. This means that the difference between the surface shape of the reference surface 35a of the reference lens 35 and the surface shape of the surface 1a of the DUT 1 has been measured.

Next, a method of measuring the surface shape of the back surface 1b of the DUT 1 will be described. The reflection mirror 34a that has just been put into the optical path is put out of the optical path. Similarly to the above, the light beam emitted from the laser light source 15 travels to the reflection mirror 34a, but here, since the reflection mirror 34a is out of the optical path, the light beam proceeds straight and continues to the next reflection mirror 3a.
It will bend in the vertical direction at 4d. After that, this light beam enters the reference lens 36, but most of the light beam is transmitted, reflected on the back surface 1b of the DUT 1, and becomes a measurement light wave. On the other hand, the light wave reflected by the reference surface 36a of the reference lens 36 becomes a reference light wave. The reference light wave and the measurement light wave overlap again to interfere with each other and return along the optical path where they came. The light is detected by an interference fringe detecting means 38 such as a CCD camera via a reflection mirror 34d, a collimator lens 33, a half mirror 32, and a condenser lens 37. Thereby, the difference between the surface shapes of the reference surface 36a of the reference lens 36 and the back surface 1b of the DUT 1 can be measured.

As described above, the optical path is switched by moving the reflection mirror 34a in and out of the optical path, and the surface of the surface 1a of the device 1 is held while the device 1 is held in the horizontal direction as in the use state. The shape or the surface shape of the back surface 1b of the DUT 1 can be measured.

[0009]

However, among the above-mentioned conventional three-dimensional shape measuring machines, in the apparatus shown in FIG. 9, YZ-XZ-Z perpendicular to the XYZ axes are respectively used.
Although the reference mirrors 29, 30, and 5 are arranged on the ZY plane to enable high-accuracy measurement, when measuring both sides of the DUT 1, it is troublesome to reverse the direction of the DUT 1 after single-sided measurement. Required. When the DUT 1 is used while being held in the horizontal direction, the measurement is performed in a state in which the shape of the lower surface of the DUT 1 is different from that in use, that is, with the lower surface of the DUT 1 turned upside down. As a result, there is a problem in that the measurement result includes an error due to the distortion due to gravity as an error.

In the surface shape measuring device shown in FIG. 10, when the device under test 1 is used while being held in a horizontal direction,
By switching the optical system, the surface shape of both surfaces of the device under test 1 can be measured while the device under test 1 is held in the horizontal direction as in the use state, but interference is used in the surface shape measurement. In addition, if the difference between the measurement lightwave and the reference lightwave is too large, the measurement cannot be performed.

The present invention solves the inconveniences of the conventional example, and allows the object to be measured to be held in the same horizontal direction as at the time of use without inverting the object or utilizing interference. Surface shape can be measured with high accuracy.
It is an object of the present invention to provide a three-dimensional shape measuring instrument having a simple configuration and a measuring method therefor.

[0012]

In order to achieve the above object, according to the first aspect of the present invention, a non-contact optical probe which can be moved in a horizontal direction and in a direction perpendicular thereto is provided in a shape of an object to be measured. In a three-dimensional shape measuring device that scans along a three-dimensional shape of an object to be measured, the optical probe includes:
An upper surface optical probe that scans along the upper surface shape of the object to be measured, and a lower surface optical probe that scans along the lower surface shape of the object to be measured, and the scanning positions of the upper surface optical probe and the lower surface optical probe Or position detection means for detecting the scanning position and the rotation angle of the object as three-dimensional position information, and movement error detection means for detecting a movement error caused by scanning of the optical probe or rotation of the object. And calculating the shapes of the upper surface and the lower surface of the measured object from the detection results of the position detecting means and the motion error detecting means.

The invention according to claim 2 is characterized in that the horizontal direction is the R axis, the vertical direction is the Z axis, and the rotation direction around the Z axis is the θ axis.
In a three-dimensional shape measuring machine that uses a Z coordinate system to scan a non-contact optical probe to measure the shape of an object to be measured held in the same horizontal direction as at the time of use, the optical probe includes:
An upper surface optical probe that scans along the upper surface shape of the object to be measured, and a lower surface optical probe that scans along the lower surface shape of the object to be measured, wherein the upper surface optical probe is movable on the upper surface in the R-axis direction. The lower surface optical probe is disposed on an R stage and an upper surface Z stage movable in the Z axis direction, and the lower surface optical probe is disposed on a lower surface R stage movable in the R axis direction and a lower surface Z stage movable in the Z axis direction. The device under test is mounted on a θ stage that is rotatable in the θ axis direction and includes a rotor portion and a housing portion that supports the rotor portion, and the upper surface optical probe and the lower surface light It detects the scanning position of the probe and the θ-axis rotation angle of the object to be measured as three-dimensional position information, and includes position detecting means arranged on the same RZ plane, scanning of the optical probe, and scanning of the object. It is for detecting a motion error caused by rotation of the fixed object, and comprises a motion error detecting means arranged on the same R-Z plane, wherein the position detecting means and the motion error detecting means detect It is characterized in that the shapes of the upper surface and the lower surface of the object to be measured are calculated.

According to a third aspect of the present invention, in the second aspect of the present invention, the position detecting means includes an R-axis position detecting means for detecting position information of the optical probe in the R-axis direction; It is characterized by comprising Z-axis position detecting means for detecting axial position information, and θ-axis position detecting means for detecting the rotation angle of the θ stage.

According to a fourth aspect of the present invention, in the second or third aspect, the R-axis position detecting means includes an R reference mirror disposed in the Z-axis direction, and the upper and lower Z stages. And a laser length measuring device which is mounted two by two and emits in a direction perpendicular to the R reference mirror.

According to a fifth aspect of the present invention, in the second or third aspect, the Z-axis position detecting means includes a Z reference mirror disposed in the R-axis direction, and the upper and lower Z stages. And a laser length measuring device which is attached one by one and emits in a direction perpendicular to the Z reference mirror.

According to a sixth aspect of the present invention, in the second or third aspect, the θ-axis position detecting means includes a θ scale provided on the rotor section for detecting a rotation angle of the θ stage. , And a scale detecting unit for detecting this.

According to a seventh aspect of the present invention, in the second aspect of the present invention, the motion error detecting means is disposed on a θ thrust reference mirror disposed on the rotor section of the θ stage, and on an outer peripheral surface of the rotor section. A radial reference mirror, a θ radial measurement reference mirror provided at least on two sides facing the θ radial reference mirror at a predetermined interval, and disposed near both ends of the upper surface and the lower surface Z reference mirror, respectively. It is characterized by comprising a reference mirror for measuring up-and-down expansion and contraction provided on four sides for detecting a distance variation between the upper and lower Z reference mirrors, and at least six laser length measuring devices for measuring the distance between these reference mirrors. And

According to an eighth aspect of the present invention, the three-dimensional shape of the measured object is measured by scanning the non-contact type optical probe movable in the horizontal direction and the vertical direction along the shape of the measured object. In the three-dimensional shape measuring method, when the upper surface shape and the lower surface shape of the object to be measured are scanned by the optical probe, the optical probe is moved in a horizontal direction so that the distance between the object and the optical probe is always substantially constant. Scanning along the shape of the object to be measured while moving in the vertical direction, and at this plurality of arbitrary positions during this scanning, the position information of the optical probe and its motion error information were detected and calculated from these information. It is characterized in that the shapes of the upper surface and the lower surface of the object to be measured are calculated based on the three-dimensional position information.

According to a ninth aspect of the present invention, there is provided an R-θ-axis in which the horizontal direction is the R axis, the vertical direction is the Z axis, and the rotation direction around the Z axis is the θ axis.
In a three-dimensional shape measuring method for measuring the three-dimensional shape of an object held in the same horizontal direction as the time of use by scanning the optical probe using a Z coordinate system, the upper surface shape and the lower surface shape of the object are measured. When scanning with the optical probe, so that the distance between the object to be measured and the optical probe is always substantially constant,
While moving the optical probe in the R-axis direction and the Z-axis direction, the optical probe is scanned along the shape of the object to be measured. During this scanning, position information and motion error information of the optical probe are detected at a plurality of arbitrary positions. The shape of the upper surface and the lower surface of the object to be measured is calculated based on the three-dimensional position information calculated from these information.

According to a tenth aspect of the present invention, there is provided the fourth aspect of the present invention.
Or the position information includes a distance Ru between the upper surface R reference mirror and the upper surface optical probe, a distance Zu between the upper surface Z reference mirror and the upper surface optical probe, a distance Rd between the lower surface R reference mirror and the lower surface optical probe, Detected from the distance Zd between the lower Z reference mirror and the lower optical probe, deviations Pu and Pd of the distance between the optical probe and the DUT generated during scanning of the upper and lower optical probes, and the rotation angle Rθ of the DUT. It is characterized by doing.

According to an eleventh aspect, in the seventh or ninth aspect, the motion error information includes a motion error θSD in the thrust direction of the θ stage, a motion error θRD in the radial direction of the θ stage, and the upper surface. It is characterized in that it is detected from the fluctuation VD between the Z reference mirror and the lower surface Z reference mirror.

According to a twelfth aspect of the present invention, in the method of the second or ninth aspect, when measuring the top surface shape of the object to be measured,
While the upper surface optical probe is scanning along the upper surface shape, the lower surface optical probe is held on the rotation axis of the θ stage to detect a vertical vibration component of the object to be measured, and the lower surface of the object to be measured. When measuring the shape, while the lower surface optical probe scans along the lower surface shape, the upper surface optical probe is held on the rotation axis of the θ stage to detect vertical vibration components of the object to be measured, and these are detected. It is characterized in that the upper surface shape or the lower surface shape is corrected based on the vertical vibration component obtained.

According to a thirteenth aspect of the present invention,
In the invention according to the ninth aspect, when measuring the upper surface shape of the object to be measured, the upper surface optical probe is simultaneously scanned along the upper surface shape of the object to be measured, and the lower surface optical probe is simultaneously scanned along the lower surface shape. I have.

[0025]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a structural view of a main part of a three-dimensional shape measuring instrument showing an embodiment of the present invention, FIG. 2 is a side view showing the three-dimensional shape measuring instrument of FIG. 1, and FIG. FIG. 4 is an arrangement diagram showing a θ stage, FIG. 5 is an optical diagram showing an optical probe, and FIG. 6 is a Z diagram.
FIG. 7 is a block diagram showing a servo configuration of the axis, and FIG. 7 is an optical arrangement diagram showing a laser length measuring device. 1 and 2, 1
Denotes an object to be measured, which is an axisymmetric aspheric lens which is used while being held in the horizontal direction. On the upper surface side and the lower surface side of the DUT 1, an upper surface optical probe 2u and a lower surface optical probe 2d that scan along the shape of the DUT 1 are arranged. Here, a non-contact type optical probe that does not damage the lens is employed.

First, the configuration of the measurement system on the upper surface 1u side of the DUT 1 will be described. Reference numeral 3u denotes an upper surface R stage that moves in parallel with the DUT 1, that is, moves in the horizontal direction.
Is an upper surface Z stage that moves in the vertical direction with respect to. Therefore, upper surface R stage 3u and upper surface Z stage 4u
The upper optical probe 2u is configured to be movable in the RZ direction. 5u is an upper surface R reference mirror arranged parallel to the R axis and at the position of the RZ surface, and 6u is an upper surface R reference mirror arranged parallel to the Z axis and at the position of the RZ surface.

Next, the configuration of the measurement system on the lower surface 1d of the DUT 1 will be described. Reference numeral 3d denotes a lower surface R stage that moves in parallel with the DUT 1, that is, moves in the horizontal direction, and 4d denotes a lower Z stage that moves in a direction perpendicular to the DUT 1. Therefore, the optical probe 2d on the lower surface R stage 3d and the lower surface Z stage 4d is configured to be movable in the RZ direction. 5d is a lower surface Z reference mirror arranged parallel to the R axis and at the position of the RZ surface, and 6d is a lower surface R reference mirror arranged parallel to the Z axis and at the position of the RZ surface. . Numeral 40 denotes a θ stage comprising an air bearing, which is means for rotating the DUT 1 in the θ-axis direction (Z-axis rotation direction). stage 40 is composed of a rotating-side rotor section 8 and a fixed-side housing section 7 that rotatably supports the rotor section. Although details will be described later, the scale 13 and the θ reference mirrors 14a, 1
4b (see FIG. 4).

The component denoted by 9 is a laser length measuring device (collectively referred to as a laser length measuring device 9) for detecting the positions of the optical probes 2u and 2d on the RZ plane. 9a
u and 9bu are for upper surface R measurement, and 9ad and 9bd are for lower surface R measurement. Here, two are each used to eliminate the influence of Abbe error. 9cu is for upper surface Z measurement,
9cd is for lower surface Z measurement,
Since the cat's eye points created by u and 2d are arranged on lines extending in parallel with the Z axis, Abbe errors do not occur.

The upper and lower surface R reference mirrors 6u, 6
d, R-axis position detection means of the optical probes 2u, 2d is constituted by the laser length measuring devices 9au, 9bu, 9ad, 9bd, and the Z-axis position is determined by the upper and lower surface Z reference mirrors 5u, 5d and the laser length measuring devices 9cu, 9cd. Detection means is configured.

Further, 9d and 9e are for measuring θ thrust,
9f and 9g are laser length measuring devices for θ radial measurement, and 9h and 9i are laser length measuring devices for vertical expansion and contraction measurement, each of which is used as a part of a motion error detecting means for detecting a distance variation during the measurement. 10 is θ on the rotor portion 8 of the air bearing.
This is a scale detection unit that detects the rotation angle of the scale 13 (see FIG. 4). The scale 13 and the scale detector 10 constitute a θ-axis position detector.

11a and 11b are reference mirrors for θ radial measurement, 11c and 11d are near both sides of the upper Z reference mirror 5u, and 11e and 11f are reference mirrors for vertical expansion and contraction arranged near both sides of the lower Z reference mirror 5d. It is a mirror. 12u is upper surface R stage 3u and upper surface Z stage 4u
12d is lower surface R stage 3d and lower surface Z
This is a mount on which the stage 4d is mounted.

As shown in FIG. 2, the upper surface optical probe 2u,
Laser length measuring device 9 for lower surface optical probe 2d and optical probes 2u and 2d (only a typical laser length measuring device is shown in the figure)
Are all arranged on the RZ plane.

The R axis position detecting means, the Z axis position detecting means, and the θ axis position detecting means constitute a position detecting means.

FIG. 3 shows the arrangement of the laser length measuring device 9. In the figure, the distance between the laser length measuring device 9 and the upper surface R reference mirror 6u is Ru, and Rlu is the laser length measuring device 9
au and the distance between the upper surface R reference mirror 6u, and R2u the distance between the laser length measuring device 9bu and the upper surface R reference mirror 6u, respectively, which are used for the amount of movement of the upper surface R stage 3u and the Abbe error correction generated during the movement. I do. Zu indicates the distance between the laser length measuring device 9cu and the upper surface Z reference mirror 5u, Pu indicates the deviation of the phase difference output from the upper surface optical probe 2u, and indicates the movement amount of the upper surface Z stage 4u and Z such as Z direction vibration. Used to correct measurement error factors that occur in the direction. Similarly, the distance between the laser length measuring device 9 and the lower surface R reference mirror 6d is Rd, Rld is the distance between the laser length measuring device 9ad and the lower surface R reference mirror 6d, and R2d is the laser length measuring device 9bd.
And the distance between the lower R reference mirror 6d and the distance between the lower R stage 3d and the Abbe error generated during the movement. Zd indicates the distance between the laser length measuring device 9cd and the lower surface Z reference mirror 5d, Pd indicates the deviation of the phase difference output from the lower surface optical probe 2d, and the Z amount such as the movement amount of the lower surface Z stage 4d and the vibration in the Z direction. Used to correct measurement error factors that occur in the direction. θSD (θSD1, θSD2) is θ
The distance between the θ reference mirror 14a on the thrust surface of the stage 40 and the upper surface Z reference mirror 5u is shown.
Is used to detect the amount of shake (surface shake) in the thrust direction.
ΘRD (θRD1, θRD2) indicates the distance between the θ reference mirror 14b and the radial measurement mirrors 11a, 11b on the radial surface of the θ stage 40, respectively, and indicates the amount of radial shake (axis shake) of the θ stage 40. Used for detection. VD (VD1, VD2) is reference mirrors 11c, 11d, 11 for vertical expansion and contraction installed on the upper and lower surfaces.
Indicates the distance between e and 11f, and is used for error correction of a distance variation between the upper surface Z reference mirror 5u and the lower surface Z reference mirror 5d during measurement. Rθ indicates the rotation angle of the θ stage 40 detected based on the θ scale 13.

The air bearing portion serving as the θ stage 40 is means for rotating the DUT 1 in the θ axis direction as shown in FIG. In the figure, reference numeral 7 denotes a fixed housing part, and reference numeral 8 denotes a rotating rotor part. The θ reference mirrors 14a and 14b are formed on a part of the surface of the rotor unit 8 by aluminum deposition and polishing after precision processing, and the θ thrust reference mirror 14a for the thrust direction is formed on a part of the upper surface of the rotor unit 8. A radial reference mirror 14b for the radial direction is provided on the entire outer peripheral surface of the rotor unit 8. By measuring the distance between the upper surface Z reference mirror 5u and the θ thrust reference mirror 14a using the laser length measuring devices 9d and 9e (see FIG. 2), it is possible to detect a change in the thrust direction when the θ stage is driven. Similarly, by measuring the distance between the radial measurement reference mirrors 11a and 11b and the θ radial reference mirror 14b using the laser length measuring devices 9f and 9g (see FIG. 2), the radial direction fluctuation during the θ stage movement is detected. it can. Also, a θ scale 13 is attached in the radial direction,
The rotation angle Rθ of the θ stage 40 can be detected using the scale detection unit 10.

The θ thrust reference mirror 14a, θ radial reference mirror 14b, radial measurement reference mirror 11
a, 11b, reference mirrors 11c, 11 for vertical expansion and contraction measurement
d, 11e, 11f, laser length measuring devices 9d, 9e, 9f,
The motion error detecting means is constituted by 9g, 9h and 9i.

FIG. 5 shows the detailed structure of the upper and lower optical probes 2u and 2d. In the figure, reference numeral 15 denotes a laser light source that generates two light waves whose polarization directions are orthogonal to each other. The light wave emitted from the laser light source 15 is expanded by the beam expander 16 and then divided into a reflected light wave and a transmitted light wave by the polarization beam splitter 17a. The reflected light wave changes from linearly polarized light to circularly polarized light by passing through the λ / 4 plate 18a, and is incident on the DUT 1 via the condenser lens 20a. Here, the object 1 is measured in a state where the light beam is focused on the light by the condenser lens 20a (cat's eye point).
And is reflected as a measurement light wave. Although details will be described later, the Z axis servo is adjusted so that the object to be measured 1 is always incident at the cat's eye point. The reflected measurement light wave returns to the original optical path and passes again through λ /
The linearly polarized light is rotated by 90 ° as compared with the outgoing light by the four plates 18a, and is transmitted by the polarizing beam splitter 17a this time. The other transmitted light wave at the polarization beam splitter 17a is changed from linearly polarized light to circularly polarized light through the λ / 4 plate 18b, enters the reference plane mirror 19, and is reflected as a reference light wave. The reflected reference light wave passes again through λ / 4.
The light becomes linearly polarized light rotated by 90 ° as compared with the outgoing light at the plate 18b, and is reflected at this time by the polarizing beam splitter 17a. The measurement lightwave and the reference lightwave overlap each other in the polarization beam splitter 17a, and pass through the polarizing plate 21 in the 45 ° azimuth to become an interference lightwave. This interference light wave is transmitted to the beam splitter 1
The interference light wave split into two by 7b and transmitted as it is is detected by the line sensor 22. Line sensor 22
There are usually several tens to several thousand channels, and here, a high frequency response type capable of detecting an interference light wave having about several tens channels is used. The selection condition when one channel is selected from a plurality of line sensor output channels and used as a measurement signal is such that an inclination angle is calculated from a design shape of the DUT 1 at a measurement point, and In the normal direction, that is, by tracing the light wave of the specularly reflected light, which channel on the line sensor 22 receives the light flux is calculated and stored in advance, and the multiplexer selects the channel to be used depending on the measurement position. Will be. Further, the interference light wave reflected by the beam splitter 17b is captured by the photodetector 23 via the condenser lens 20b and becomes a reference signal.

FIG. 6 shows the configuration of the Z-axis servo. However, the upper surface 1u side and the lower surface 1d side of the DUT 1 have the same configuration, but here, the upper surface 1u side will be described as an example. The upper surface Z stage 4u is moved so that the light beam from the optical probe 2u enters the DUT 1 at the cat's eye point. From the interference light wave in that state, the line sensor 22
The measurement signal detected via the multiplexer 44 (see FIG. 5) and the reference signal from the photodetector 23 (see FIG. 5) are input to the phase meter 41, respectively. The phase difference Puo is calculated by the phase meter 41, and the computer 4
When it is stored in 2, the Z-axis servo by the Z servo controller 43 is started. Next, the upper surface R stage 4u and the θ stage 40 are moved simultaneously or independently, and the phase difference Pui obtained at that time is compared with the stored phase difference Puo, so that the deviation ΔPui is always zero or almost zero. Then, the Z servo controller 43 moves the upper surface Z stage 4u (servo lock state).

Deviation ΔPui = Pui−Puo At this time, if the deviation ΔPui is corrected and reflected in the measurement data later, an accurate value obtained by correcting the error in the servo lock can be obtained. In this manner, the upper surface optical probe 2u scans and measures the upper surface 1u of the object 1 while the distance between the object 1 and the upper surface optical probe 2u is always kept constant or substantially constant.

FIG. 7 shows the structure of the laser length measuring device 9. FIG. 7A shows a type for measuring the distance between a laser length measuring device and one reference mirror.
The configuration of u, 9bu, 9cu, 9ad, 9bd, 9cd is shown. In this case, the measurement resolution of the laser length measuring device is doubled because the double path method is used in which the optical path to be measured is reciprocated twice. In FIG. 1A, reference numeral 15 denotes a laser light source that generates two light waves whose polarization directions are orthogonal to each other. The light beam emitted from the laser light source 15 is divided into a reflected light wave and a transmitted light wave by the polarization beam splitter 17c. The transmitted light wave is reflected twice by the corner cube 24a to become a reference light wave, and passes through the polarization beam splitter 17c again. One reflected light wave changes from linearly polarized light to circularly polarized light by passing through the λ / 4 plate 18c, and is reflected by a reference mirror (for example, the upper surface Z reference mirror 5u) to become a measurement light wave.
The measurement light wave returns to the original optical path, becomes linearly polarized light rotated by 90 ° as compared with the outgoing light at the λ / 4 plate 18c passing again, transmitted through the polarization beam splitter 17c, and reflected twice by the corner cube 24b. Again the polarizing beam splitter 17
c and returns to the reference mirror through the λ / 4 plate 18c. The measurement light wave reflected again becomes linearly polarized light rotated by 90 ° as compared with the outgoing light on the λ / 4 plate 18c, and is reflected on the polarization beam splitter 17c. Here, the measurement lightwave and the reference lightwave overlap each other, become an interference lightwave when passing through the polarizing plate 21, and are detected by the length measuring device receiver 25. The change in the phase difference between the measurement lightwave and the reference lightwave is observed by the length measuring device receiver 25 as the count of the fringe of the interference lightwave. Since the optical path length of the reference light wave is always constant, the variation of the measurement light wave, that is, two round trips of each stage movement from each reference mirror can be detected here from the count of the interference light wave fringes.

Similarly, FIG. 7B shows a type for measuring the distance between two reference mirrors.
f, 9g, 9i, 9h are shown. Fig. (B)
In, two orthogonal light waves emitted from the laser light source 15 are divided into a reflected light wave and a transmitted light wave by the polarization beam splitter 17c. Transmitted light wave is corner cube 24a
Are reflected twice, become reference light waves, and again pass through the polarization beam splitter 17c. One reflected light wave is
When the light passes through the λ / 4 plate 18c, the light is changed from linearly polarized light to circularly polarized light. The measurement light wave returns to the original optical path, becomes linearly polarized light rotated by 90 ° as compared with the forward path at the λ / 4 plate 18c which passes again, passes through the polarization beam splitter 17c, and passes through the λ / 4 plate 18d for reference. The light is reflected by a mirror (for example, the θ thrust reference mirror 14a) and returns to the original optical path.
The measurement light wave again incident on the λ / 4 plate 18d becomes linearly polarized light rotated by 90 ° as compared with the outward path, is reflected by the polarization beam splitter 17c, and is incident on the corner cube 24a. The measurement light wave is reflected twice by the corner cube 24a, reenters the polarization beam splitter 17c, and is reflected there. Thereafter, the measuring light wave passes through the λ / 4 plate 18d again and returns to the reference mirror (for example, the θ thrust reference mirror 14).
The light is reflected by a), transmitted through the λ / 4 plate 18d, the polarization beam splitter 17c, and the λ / 4 plate 18c, again incident on the reference mirror (for example, the upper surface Z reference mirror 5u) and reflected.
The measurement light wave reflected by the reference mirror is again applied to the λ / 4 plate 1.
8c, the light becomes linearly polarized light rotated by 90 ° compared to the outward path, and is reflected by the polarization beam splitter 17c. Here, the measurement lightwave and the reference lightwave overlap, and when passing through the polarizing plate 21, become an interference lightwave.
Is detected by The variation of the phase difference between the measurement lightwave and the reference lightwave is
It is observed by the length measuring device receiver 25 as the count of the fringe of the interference light wave. Since the optical path length of the reference light wave is always constant, a change in the optical path length of the measured light wave, that is, two round trips of the amount of change in the distance between the two reference mirrors is detected from the count of the interference light wave fringes. it can.

Next, a specific measuring method using the three-dimensional shape measuring instrument of this embodiment will be described with reference to FIG. The axisymmetric symmetric lens, which is the DUT 1, is set so that its axis substantially coincides with the rotation axis of the θ stage 40. Thus, by combining the θ-axis rotation on the DUT 1 side and the RZ-axis scanning on the optical probes 2u and 2d, the optical probes 2u and 2d are adjusted to the shape of the DUT 1 over the entire surface. You will be able to scan.

First, a method for measuring the shape of the upper surface 1u of the DUT 1 will be described. The upper surface optical probe 2u is moved to the rotation center of the θ axis using the upper surface R stage 3u, and then the upper surface Z stage 4u is lowered to approach the DUT 1, and a cat's eye point generated by the light beam of the upper surface optical probe 2u. Is adjusted to be incident on the DUT 1, and servo lock is started. The upper surface optical probe 2u is used while scanning the upper surface R stage 3u and following the Z-axis servo according to the surface shape of the DUT 1 to move the upper surface Z stage 4u.

Similarly, the lower surface optical probe 2d is moved to the rotation center of the θ axis by using the lower surface R stage 3d, and thereafter, the lower surface Z stage 4d is raised to approach the DUT 1, and The state is adjusted so that the cat's eye point generated by the light beam of the probe 2d is incident on the DUT 1, and servo lock is started. In addition, the lower surface optical probe 2
During the measurement, d is not moved while the position of the R-axis is maintained during the measurement, and the DUT 1 is moved by following the Z-axis servo only by the vertical movement of the Z-axis due to vibration or the like.

Here, when the servo lock is started, each measurement data at the start is taken as reference data. That is, the laser length measuring devices 9au to 9cu, 9cd, 9d
R1u, R2u, Z1u, Z1d, θ
D1, θD2, θD3, θD4, VD1, VD2, the output value RE of the rotary encoder 10, and the data of the phase deviations Pu, Pd of the Z-axis servo are R1uo,
R2o, Z1o, Z1o, θD1o, θD2o, θD3o, θ
D4o, VD1o, VD2o, REo, Puo, and Pdo are stored in the computer 42. Next, the upper surface R stage 3u and the θ stage 40 remain in the servo locked state.
Are moved independently or simultaneously, and the laser length measuring device 9 is measured at arbitrary plural points (i = 1 to n, i: order of capture).
The output values of au to 9cu, 9cd, 9d to 9i, the output value RE of the rotary encoder 10, and the deviation of the phase of the Z-axis servo are simultaneously captured, and R1ui, R2ui, Z1 are respectively obtained.
i, Z1i, θD1i, θD2i, θD3i, θD4i, VD
1i, VD2i, REi, Pui, and Pdi are stored in the computer 42. Similarly, a total of n sets of measurement data are fetched while scanning the measurement areas of the DUT 1 with the optical probes 2u and 2d. For example, by performing the following arithmetic processing, the shape of the upper surface 1u of the DUT 1 can be expressed as n sets of three-dimensional data (R2ui, θui, Zui) of the R-θ-Z coordinate system. Measurement accuracy can be realized on the order of nm.

1. R coordinate: Rui Ridata = ((R1ui−R1uo) + (R2ui−R2)
uo)) / 2 Abbe error = ((R1ui−R1uo) + (R2ui−
R2uo)) × (D1u / D2u) Shaft runout error = ((θD3i−θD3o) + (θD4i−
θD4o)) / 2 Rui = Ridata + Abbe error + Shaft runout error 2. θ coordinate: θui θui = REi-REo Z coordinate: Zui Servo deviation = Pui−Pu Surface runout error = ((θD1i−θD1o) + (θD2i−
θD2o)) / D3 × formu (Ridata) Z direction vibration = (Z1di−Z1do) + (Pdi−
Pdo) Zui = Z1ui + servo deviation + surface runout error + Z direction vibration D1u: distance of the Z direction component between the middle of laser length measuring devices 9au, 9bu and the cat's eye point of the optical probe D2u: laser length measuring device 9au , 9bu in the Z direction D3: distance in the R direction between the laser length measuring devices 9d and 9e formu (Ridata): function calculated from the relationship between the upper surface design shape and Ridata In addition, the lower surface 1d of the DUT 1 The shape is measured as follows. After moving the upper surface optical probe 2u to the servo lock position on the rotation axis of the θ axis by using the upper surface R stage 3u and the upper surface Z stage 4u, the measurement object is not moved while the position of the R axis is maintained during the measurement. 1 is moved by following the Z-axis servo only by the amount that the Z-axis vertically moves due to vibration or the like.
After moving the lower surface optical probe 2d to the servo lock position on the rotation axis of the θ axis using the lower surface R stage 3d and the lower surface Z stage 4d, the lower surface R stage 3d and the θ stage 40 are moved independently or simultaneously. become.
As in the case of the upper surface 1u, the reference data at the start of the servo lock may be fetched. Note that the measurement data taken in at this time is the same data R1d, R2d,
Z1u, Z1d, θD1, θD2, θD3, θD4, R
E, Pu, and Pd.

The shape of the lower surface 1d of the DUT 1 can be represented as three-dimensional data (Rdi, θdi, Zdi) of n sets of R-θ-Z coordinate systems by performing arithmetic processing as follows. The measurement accuracy can be realized on the order of nm.

1. R coordinate: Rdi Ridata = ((R1di−R1do) + (R2di−R2)
do)) / 2 Abbe error = ((R1di−R1do) + (R2di−
R2do)) × (D1d / D2d) Shaft runout error = ((θD3i−θD3o) + (θD4i−
θD4o)) / 2 Rdi = Ridata + Abbe error + shaft run-out error θ coordinate: θdi θdi = REi−REo Z coordinate: Zdi Servo deviation = Pdi−Pdo Plane runout error = ((θD1i−θD1o) + (θD2i−
θD2o)) / D3 × formd (Ridata) Z-direction vibration = (Z1ui−Z1uo) + (Pui−
Puo) Expansion / contraction between reference mirrors = ((VD1i−VD1o) + (VD2
i-VD2o)) / 2 Zdi = Z1di + servo deviation + surface deflection error + Z direction vibration + expansion between reference mirrors D1d: Z direction between the middle of the laser length measuring devices 9ad and 9bd and the cat's eye point of the optical probe Component distance D2d: distance in the Z direction of laser length measuring devices 9ad, 9bd D3: distance in the R direction between laser length measuring devices 9d, 9e formu (Ridata): calculated from the relationship between the top surface design shape and Ridata Function Among the motion errors, the θ thrust measurement is performed with reference to the upper surface Z reference mirror 5u, and the thickness of the DUT 1 may be measured. As described above, a correction for the expansion and contraction between the reference mirrors is added.

FIG. 8 shows an example of taking in data of three patterns viewed on the R-θ cross section. However, the axes in the figure are those converted to the commonly used XY coordinate system. In the present invention, the R stages 3u, 3d
If the data is captured at equal intervals while independently moving the θ stage 40 and the θ stage 40, the R stage 3u, 3d and the θ stage 40 are not moved at the same time as the spiral data shown in FIG. If data is captured at regular intervals while moving independently, it can be detected as concentric circle data shown in FIG. In general, the grid data shown in FIG. 3C, which is often used in a three-dimensional shape measuring instrument, is such that the movement amounts of the R stages 3u and 3d and the θ stage 40 are adjusted in a grid pattern, or spiral data or concentric data is obtained. The present invention can also cope with a method of performing conversion using coordinate conversion or interpolation.

In the present invention, when the shape of the DUT 1 is axially symmetric, when data is detected by the spiral data, the light that moves in the servo lock state with respect to the θ stage 40 and the minute R stages 3 u and 3 d moves. Probe 2u, 2d
Is extremely small in the Z direction, so that high-speed optical probe scanning becomes possible. When data detection is performed using concentric circle data, after moving the R stages 3u and 3d, the state is maintained, and the data can be captured at equal intervals while the θ stage 40 is independently moved.
Similarly to the above, the amount of movement of the optical probes 2u and 2d moving in the Z direction in the Z direction with respect to the movement of the θ stage 40 becomes extremely small, so that high-speed optical probe scanning becomes possible.

As described above, in the three-dimensional shape measuring apparatus of the present invention, the DUT 1 is mounted on the θ stage 40, and the optical probes 2u and 2d are arranged on the upper surface 1u side and the lower surface 1d side of the DUT 1, respectively. During the scanning of the optical probes 2u and 2d, the positions of the R and Z axes of the optical probes 2u and 2d, the rotational position of the θ-axis of the DUT 1, and various motion errors are detected at a plurality of arbitrary positions in synchronization. Then, the shape measurement of the upper surface 1u and the lower surface 1d of the DUT 1 is performed based on the three-dimensional position information calculated therefrom.

The present embodiment described above corresponds to FIGS.
There are three points significantly different from the conventional example shown in FIG. One of them is to dispose an upper optical probe 2u and a lower optical probe 2d independently on the upper surface 1u side and the lower surface 1d side of the DUT 1, and to hold the DUT 1 in the horizontal direction while keeping the DUT 1 horizontal. This is the point where the 3D shape of the upper surface 1u and the lower surface 1d of the DUT 1 is measured by scanning 2d on the upper surface 1u and the lower surface 1d of the DUT 1. 2
The third is to configure the coordinate system as an R-θ-Z system, and as means for detecting the position information of the optical probes 2u and 2d on the R axis and the Z axis, respectively, on the upper surface 1u side and the lower surface 1d side of the DUT 1. R reference mirrors 5u, 5d, Z reference mirrors 6u, 6
d is arranged and detected using the laser length measuring devices 9au, 9ad, etc., and the scale detector 10 attached to the θ stage 40 is read by the scale detector 10 as means for detecting the position information of the θ axis. is there. Third, in order to detect a motion error during measurement, a plurality of reference mirrors are arranged to correct the measurement result.

Therefore, when the device under test 1 is used while being held in the horizontal direction, the shape measurement of the upper surface 1u and the lower surface 1d of the device 1 under test can be performed in the same state as at the time of use. In addition, the measurement results of the shape of the lower surface 1d do not cause a distortion error due to gravity caused by inverting the DUT 1, thereby enabling highly accurate surface shape measurement. In addition, since the surface shape is measured using the optical probes 2u and 2d, a reference wavefront used in interference measurement is not required, and it is possible to cope with various shape measurements of an object to be measured.

The upper surface 1u and the lower surface 1d of the DUT 1
By measuring the shape at the same time, the measurement time can be reduced.

Next, a second embodiment will be described.
In this embodiment, as in the first embodiment, the upper surface 1u shape and the lower surface 1d shape of the DUT 1 are measured at the same time, but the measurement time is substantially reduced even if some measurement accuracy is sacrificed. This is an example that can be reduced to about half. As shown in FIG. 1, the upper surface optical probe 2u is moved to the rotation center of the θ axis using the upper surface R stage 3u, and then the upper surface Z stage 4u is lowered to approach the DUT 1;
The state where the cat's eye point generated by the light beam of the upper surface optical probe 2u is incident on the DUT 1 is started, and the servo lock is started. Similarly, the lower surface optical probe 2d is set to θ
After being moved to the rotation center of the shaft using the lower surface R stage 3d, the lower surface Z stage 4d is raised to approach the DUT 1, and the cat's eye point generated by the light beam of the lower surface optical probe 2d becomes the DUT 1. Adjust to the incident state and start servo lock. The scanning by the upper surface optical probe 2u and the lower surface optical probe 2d is performed by following the Z-axis servo according to the surface shape of the DUT 1.

Reference data (i =
0) and any measurement data at arbitrary points (i = 1 to n, i: acquisition order) to be measured. Note that the measurement data to be captured are R1u, R2u, Z1, Z1,
θSD1, θSD2, θRD1, θRD2, VD1, V
D2, Rθ, Pu, and Pd.

The shape of the upper surface 1u and the shape of the lower surface 1d of the DUT 1 are calculated as follows to obtain n sets of R
-Three-dimensional data of the θ-Z coordinate system (Rui-θui-Zu
i) and (Rdi-θdi-Zdi), and the accuracy measurement can be realized on the order of nm. In addition, Rui-θui-
Since Zui and Rdi-θdi-Zdi can be expressed by the same formula as in the first embodiment, they are omitted here.

Upper surface Z coordinate: Zui servo deviation = Pui−Pu surface runout error = ((θSD1i−θSD1o) + (θSD2)
i−θSD2o)) / D3 × formu (Ridata) Zui = Z1ui + servo deviation + surface deflection error • Lower surface Z coordinate: Zdi servo deviation = Pdi−Pdo surface deflection error = ((θSD1i−θSD1o) + (θSD2)
i−θSD2o)) / D3 × formd (Ridata) Expansion / contraction between reference mirrors = ((VD1i−VD1o) + (VD2)
i−VD2o)) / 2 Zdi = Z1di + servo deviation + surface deflection error + expansion between reference mirrors As described above, when the shape of the upper surface 1u and the lower surface 1d of the DUT 1 are measured at the same time, the measurement time can be reduced. You can expect.

[0060]

As described above, the optical probe comprises the upper surface optical probe that scans along the upper surface shape of the object to be measured and the lower surface optical probe that scans along the lower surface shape of the object to be measured. The upper surface optical probe is provided on an upper surface R stage movable in the horizontal R axis direction, and an upper surface Z stage movable in the vertical Z axis direction. The object to be measured is provided on a lower surface R stage movable in the R axis direction and a lower surface Z stage movable in the Z axis direction, and the object to be measured is on a θ stage movable in the θ axis direction as a Z axis rotation component. It is placed in a state held in the horizontal direction, the scanning position of the upper surface optical probe and the lower surface optical probe, and detects the θ-axis rotation angle of the DUT as three-dimensional position information,
Position detecting means arranged on the same R-Z plane, and for detecting a motion error caused by scanning of the optical probe and rotation of the object to be measured, are arranged on the same R-Z plane. Movement error detecting means, wherein the optical probe scans along the shape of the measured object while moving in the Z-axis direction so that the distance to the measured object is always substantially constant. At any given position, the position of the optical probe and the movement error thereof are synchronously detected by the position detection means and the movement error detection means, and the top and bottom surfaces of the object to be measured are calculated from this information. When the measurement object is used while being held in the horizontal direction, the shape measurement of the upper surface and the lower surface of the measurement object can be performed in the same state as at the time of use without providing a reversing mechanism or the like. The measurement result of the bottom surface Is inverted can avoid such a disadvantage distortion error due to gravity, resulting in is added, it is possible to highly accurate surface shape measurement performed. In addition, since the surface shape is measured using an optical probe and does not use light interference, a reference wavefront used in interference measurement is not required, and a device to be measured having a more diverse shape than an apparatus using interference can be obtained. Measurement becomes possible.

Further, if simultaneous measurement of the upper surface shape and the lower surface shape of the object to be measured is performed, it is possible to shorten the measurement time, which has the above-described effect.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of a three-dimensional shape measuring machine showing an embodiment of the present invention.

FIG. 2 is a side view showing the three-dimensional shape measuring machine of FIG. 1;

FIG. 3 is an arrangement configuration diagram showing an optical probe and a laser length measuring device on the RZ plane.

FIG. 4 is a schematic configuration diagram showing a θ stage.

FIG. 5 is an optical layout diagram showing a schematic configuration of an optical probe.

FIG. 6 is a block diagram illustrating a configuration of a Z-axis servo.

FIG. 7 is an optical layout diagram showing a schematic configuration of a laser length measuring device.

FIG. 8 is an explanatory diagram showing an example of a capturing pattern of position data of an optical probe.

FIG. 9 is a schematic configuration diagram showing a conventional three-dimensional shape measuring machine using XYZ coordinates.

FIG. 10 is an optical layout diagram showing a conventional three-dimensional shape measuring instrument using interference.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DUT 1u Upper surface of DUT 1d Lower surface of DUT 2u Upper surface optical probe 2d Lower surface optical probe 3u Upper surface R stage 3d Lower surface R stage 4u Upper surface Z stage 4d Lower surface Z stage 5u Upper surface Z reference mirror 5d Lower surface Z reference mirror 6u Upper surface R reference mirror 6d Lower surface R reference mirror 7 Housing unit (θ stage) 8 Rotor unit (θ stage) 9au, etc. Laser length measuring device 10 Scale detector (rotary encoder) 11a, 11b Reference mirror for θ radial measurement 11c to 11f Reference mirror for vertical expansion / contraction measurement 12u, 12d Mount 13 Scale 14a Thrust reference mirror 14b θ radial reference mirror 15 Laser light source

Continued on the front page F term (reference) 2F065 AA04 AA39 AA53 DD14 FF17 FF49 FF52 FF55 GG04 HH04 HH13 JJ02 JJ05 JJ15 JJ25 LL09 LL12 LL17 LL36 LL37 MM04 MM07 PP22 2F069 AA04 AA66 GG07H08 GG03H BA20 BA22

Claims (13)

[Claims] 1. A three-dimensional shape measuring apparatus for measuring a three-dimensional shape of an object by scanning a non-contact optical probe movable in a horizontal direction and a direction perpendicular thereto along the shape of the object. In the optical probe, an upper surface optical probe that scans along the upper surface shape of the object to be measured, and a lower surface optical probe that scans along the lower surface shape of the object to be measured, the upper surface optical probe and Position detecting means for detecting the scanning position of the lower surface optical probe, or the scanning position and the rotation angle of the object to be measured as three-dimensional position information; and a motion error caused by scanning of the optical probe and rotation of the object to be measured. A three-dimensional shape measurement, comprising: calculating a shape of an upper surface and a lower surface of the object to be measured based on detection results of the position detecting device and the motion error detecting device. Machine. 2. An object held in the same horizontal direction as in use using an R-θ-Z coordinate system in which a horizontal direction is an R axis, a vertical direction is a Z axis, and a rotation direction around the Z axis is a θ axis. In a three-dimensional shape measuring instrument for measuring the shape of a measured object by scanning a non-contact type optical probe, the optical probe is configured to scan along an upper surface shape of the measured object; A lower surface optical probe that scans along the lower surface shape of the above, the upper surface optical probe is disposed on the upper surface R stage movable in the R axis direction and the upper surface Z stage movable in the Z axis direction, The lower surface optical probe has a lower surface R stage movable in the R axis direction and a lower surface Z movable in the Z axis direction.
The object to be measured is placed on a stage, the object to be measured is mounted on a θ stage rotatable in the θ axis direction, which is composed of a rotor part and a housing part supporting the rotor part, and the upper surface optical probe And a position detecting means disposed on the same RZ plane for detecting a scanning position of the lower surface optical probe and a θ-axis rotation angle of the object to be measured as three-dimensional position information, and scanning the optical probe. And motion error detection means for detecting a motion error caused by rotation of the object to be measured, the motion error detection means being arranged on the same RZ plane, and detecting the position detection means and the motion error detection means. A three-dimensional shape measuring machine, wherein the shape of the upper surface and the lower surface of the object to be measured is calculated from the result. 3. The optical system according to claim 1, wherein the position detecting unit detects an R-axis position of the optical probe in an R-axis direction, and a Z-axis position information of the optical probe in a Z-axis direction. 3. The three-dimensional shape measuring apparatus according to claim 2, further comprising: a position detecting means; and a θ-axis position detecting means for detecting a rotation angle of the θ stage. 4. The R-axis position detecting means is mounted on the upper and lower Z-stages, two each for the upper and lower R reference mirrors arranged in parallel to the Z-axis. 4. The three-dimensional shape measuring apparatus according to claim 2, further comprising a laser length measuring device that emits light in a direction perpendicular to the lower surface R reference mirror. 5. The Z-axis position detecting means is attached to the upper and lower Z-stage mirrors, one each for the upper and lower Z-stage mirrors, which are arranged in parallel to the R-axis. The three-dimensional shape measuring apparatus according to claim 2, further comprising a laser length measuring device that emits light in a direction perpendicular to the lower surface Z reference mirror. 6. The θ-axis position detecting means includes a θ scale installed on the rotor unit for detecting a rotation angle of the θ stage, and a scale detecting unit for detecting the θ scale. The three-dimensional shape measuring apparatus according to claim 2 or 3, wherein 7. The θ-thrust reference mirror disposed on the rotor section of the θ-stage, the θ-radial reference mirror disposed on the outer peripheral surface of the rotor section, and the θ-radial reference mirror. On the other hand, a θ radial measurement reference mirror provided at least on two surfaces facing each other at a predetermined interval is disposed near both ends of the upper and lower surface Z reference mirrors, respectively, and detects a distance variation between the upper and lower surface Z reference mirrors. 3. The three-dimensional shape measuring apparatus according to claim 2, comprising four reference mirrors for measuring vertical expansion and contraction, and at least six laser length measuring devices for measuring the distance between the reference mirrors. . 8. A three-dimensional shape measuring method for measuring a three-dimensional shape of an object by scanning a non-contact optical probe movable in a horizontal direction and a direction perpendicular thereto along the shape of the object. In the above, when scanning the upper surface shape and the lower surface shape of the object to be measured with the optical probe, the optical probe is moved in a horizontal direction and a vertical direction so that a distance between the object to be measured and the optical probe is always substantially constant. While scanning along the shape of the object to be measured, and at this plurality of arbitrary positions during this scanning, the position information of the optical probe and its motion error information are detected, and the three-dimensional position information calculated from these information is obtained. A three-dimensional shape measuring method, wherein the shapes of the upper surface and the lower surface of the object to be measured are calculated based on the three-dimensional shape. 9. An R-θ-Z coordinate system in which a horizontal direction is an R axis, a vertical direction is a Z axis, and a rotation direction around the Z axis is a θ axis,
In a three-dimensional shape measuring method for measuring the three-dimensional shape of an object held in the same horizontal direction as in use by scanning an optical probe, the upper surface shape and the lower surface shape of the object are scanned by the optical probe. At this time, the optical probe is scanned along the shape of the object to be measured while moving the optical probe in the R-axis direction and the Z-axis direction so that the distance between the object and the optical probe is always substantially constant. At multiple arbitrary positions,
Detecting a position information of the optical probe and its motion error information, and calculating a shape of an upper surface and a lower surface of the object to be measured based on the three-dimensional position information calculated from the information; Measuring method. 10. The position information includes a distance Ru between the upper surface R reference mirror and the upper surface optical probe, a distance Zu between the upper surface Z reference mirror and the upper surface optical probe, a distance Rd between the lower surface R reference mirror and the lower surface optical probe, and a lower surface. The distance Zd between the Z reference mirror and the lower surface optical probe, the deviation P of the distance between the optical probe and the object to be measured generated during scanning of the upper surface optical probe and the lower surface optical probe.
10. The three-dimensional shape measuring method according to claim 4, wherein the detection is performed from u and Pd, and the rotation angle Rθ of the measured object. 11. The motion error information is detected from a motion error θSD of the θ stage in a thrust direction, a motion error θRD of the θ stage in a radial direction, and a variation VD between the upper Z reference mirror and the lower Z reference mirror. The method of measuring a three-dimensional shape according to claim 7, wherein the method is performed. 12. When measuring the shape of the upper surface of the object to be measured, the lower surface optical probe is held on the rotation axis of the θ stage while the upper surface optical probe scans along the upper surface shape. When detecting the vertical vibration component of the object, and measuring the lower surface shape of the object to be measured, while the lower surface optical probe scans along the lower surface shape, the upper surface optical probe is rotated by the rotation axis of the θ stage. 10. The method according to claim 2, wherein the vertical vibration component of the object to be measured is detected while being held at the top, and the upper surface shape or the lower surface shape is corrected based on the detected vertical vibration component. Dimensional shape measurement method. 13. When measuring the upper surface shape of the object to be measured, the upper surface optical probe is simultaneously scanned along the upper surface shape of the object to be measured and the lower surface optical probe is simultaneously scanned along the lower surface shape. The three-dimensional shape measuring method according to claim 1, 2, 8, or 9.