JP4197640B2 - Subject setting device and interferometer device provided with the subject setting device - Google Patents

Description

  The present invention has a reference surface having substantially the same shape when measuring the absolute shape of a reference surface such as a reference plate used as a reference in measurement using an interferometer by using a so-called three-surface alignment method. The present invention relates to an object placement device for placing two predetermined ones of two reference plates and the like at two predetermined positions on the optical axis of an interference optical system, and an interferometer device including the subject placement device.

  Since a reference surface such as a reference plate used in the interferometer serves as a reference for the shape of the surface to be measured when performing optical interference measurement, it needs to be formed with a very high accuracy so as to have a predetermined shape. . Conventionally, a so-called three-surface alignment method is known as a method for measuring the absolute shape of such a highly accurate reference surface (see Patent Documents 1 and 2 below).

  In this type of three-plane alignment method, measurement is generally performed in the following procedure. That is, three reference plates having substantially the same shape of reference surfaces are prepared as subjects, and predetermined two of these three subjects are sequentially selected three times with different combinations. Each time this selection operation is performed, the two selected subjects are separated from each other at a predetermined interval so that the respective reference surfaces become the measurement target surfaces at two predetermined positions on the optical axis of the interference optical system. Are arranged so as to face each other, and the relative displacement between these two faces to be measured is measured two-dimensionally. Then, a predetermined calculation is performed based on the measurement results for each of the three selections, and the absolute shape of the measurement surface (reference surface) of each subject is obtained.

  In the measurement in the predetermined two selections among the three times, an operation of rotating one of the two measured surfaces facing each other little by little relative to the other is required, and the remaining one time In the measurement in the selection, an operation of placing the subject placed in one of the two predetermined positions in the other one selection in the other of the two positions is required.

JP-A-6-281427 JP 11-37742 A

  In order to implement the three-surface alignment method as described above, a mechanism for arranging and maintaining two predetermined positions on the optical axis of the interference optical system, or one of two measured surfaces facing each other with respect to the other. Therefore, a mechanism for rotating relatively little by little is required. Conventionally, subject placement apparatuses having these mechanisms are also known. However, in the conventional subject placement apparatus, sufficient consideration is given to the following error factors associated with performing the three-plane alignment method. Not.

  That is, in the three-plane alignment method, each measurement is performed by changing the combination of the objects, so that the object is exchanged for each measurement, but the position of the object relative to the measurement optical axis (the optical axis of the interference optical system) before and after the exchange is If it changes, an error will occur. Further, it is necessary to rotate one subject little by little around the measurement optical axis at the time of measurement. If this rotation axis does not coincide with the measurement optical axis, so-called miso-spicing occurs and an error occurs. Furthermore, if the central axes of the two objects arranged opposite to each other are not parallel to the measurement optical axis, an error occurs because the relative inclination postures of the two measurement surfaces change according to the rotation of one of the objects. .

  The present invention has been made in view of such circumstances, and the error factors associated with the three-plane alignment method, that is, the positional deviation of the subject relative to the measurement optical axis when the subject is replaced, the rotational axis of the subject, and the like. And measuring optical axis, and an object placement device capable of suppressing a mismatch in inclination between the central axis of two subjects arranged opposite to each other and a measurement optical axis, and an interferometer device provided with the subject placement device The purpose is to provide.

In order to solve the above-described problem, the subject installation apparatus of the present invention includes:
A predetermined two of three subjects having measurement surfaces having substantially the same shape as each other are sequentially selected three times by changing the combination, and each time the selection operation is performed, the two selected subjects are The measurement surfaces are arranged so as to oppose each other at a predetermined interval at two predetermined positions on the optical axis of the interference optical system, and the relative displacements of these opposing measurement surfaces are measured two-dimensionally. In the subject placement apparatus for performing a three-surface alignment method for calculating the measurement result of three times to obtain the shape of the measurement surface of each subject,
First holding means for holding one of the two subjects selected by the selection operation at one of the two positions;
Second holding means for holding the other of the two subjects selected by the selection operation so as to be rotatable around a predetermined rotation axis in the other of the two positions;
When the subject held by the first and / or second holding means is exchanged with another subject, the positions of the central axes of the subjects before and after the exchange with respect to the holding means are substantially the same. Alignment means for matching;
Alignment means for causing the central axis of the subject held by the first holding means, the central axis of the subject held by the second holding means, and the rotation axis to substantially coincide with the optical axis; equipped with a,
The alignment means includes a first biaxial tilt adjustment mechanism that makes the central axis of the subject held by the first holding means substantially parallel to the optical axis, and the rotation axis substantially parallel to the optical axis. A second biaxial tilt adjusting mechanism that makes the center axis of the subject held by the second holding means substantially parallel to the rotating shaft, and the rotating shaft An axis position adjusting mechanism that substantially matches the position of the optical axis with the position of the optical axis ,
The three subjects are configured to be held by the first and second holding means via the respective frames attached to these subjects,
In each of the two predetermined positions of the frame and the fixing plate of the third biaxial inclination adjusting mechanism, each extraction pin hole through which two extraction pins for positioning adjustment are respectively communicated is formed.
Each frame attached to each of these subjects only when the alignment between the subject held by the first holding means and the subject held by the second holding means is completed. The two extraction pins can be communicated with each extraction pin hole of the body and the fixing plate of the third biaxial inclination adjusting mechanism .

Before Symbol alignment means, wherein for the positioning of the frame member and the first and / or second retaining means when the subject is exchanged to the other object, these retaining means and the frame Each of which is provided with an alignment index.

  Further, the interferometer apparatus of the present invention includes an interferometer main body section provided with the interference optical system, a subject placement apparatus of the present invention having the above characteristics, and a calculation for performing a predetermined calculation in the three-plane alignment method. It is characterized by comprising a part.

  According to the subject placement apparatus of the present invention, since the above configuration is provided, an error factor associated with performing the three-surface alignment method, that is, a positional deviation of the subject with respect to the measurement optical axis at the time of subject replacement, It is possible to suppress the mismatch between the rotation axis of the specimen and the measurement optical axis and the mismatch between the inclinations of the central axes of the two specimens arranged opposite to each other and the measurement optical axis.

  In addition, according to the interferometer apparatus of the present invention, since the subject placement apparatus of the present invention as described above is provided, the error factors associated with performing the three-plane alignment method can be suppressed. The absolute shape of the reference surface such as the reference plate can be measured with high accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an interferometer apparatus provided with a subject setting apparatus according to an embodiment of the present invention.

<Device configuration>
An interferometer apparatus 1 shown in FIG. 1 is for measuring an absolute shape of a reference surface such as a reference plate used as a reference in measurement using an interferometer by using a three-surface alignment method. A subject placement device 3 comprising a main body 2 and first and second holding means 3A, 3B is provided. In addition, the interferometer device 1 includes a monitor for observing the captured interference fringes, and a computation unit (not shown) such as a computer that executes the analysis in the interference fringe analysis and the three-plane alignment method described later. .

  The interferometer body 2 is arranged on the first holding means 3A side, and includes a light source unit that emits a light beam such as a laser beam, a magnifying lens and a collimator lens for irradiating the subject with measurement light, and the like. And an imaging optical system (all not shown) including an imaging lens for capturing an interference image of the subject and an imaging element such as a CCD. In addition, a first biaxial tilt adjusting mechanism 24 is provided at the light beam exit end of the subject, and the first biaxial tilt adjusting mechanism 24 has a fringe scan adapter 25 for shifting the phase of the interference fringes. It is attached. A frame holder 26 is attached to the fringe scan adapter 25, and a phase shift measurement is performed in a direction along the optical axis L (in the direction of the arrow in the figure) by a piezo element (not shown) in the fringe scan adapter 25. Can be finely moved. A positioning pin 41 is provided at a predetermined position on the flange portion 27 of the frame holder 26. The pin 41 and the pin hole 42 of the frame 7A, 7B, or 7C (7A in FIG. 1) holding the subject 4 or 5 or 6 (the subject 4 in FIG. 1) are fitted, and screws (not shown) are used. The frame body 7A is positioned and fixed to the flange portion 27.

  The interferometer body 2 is placed on the X stage 23 via the uniaxial tilt stage 21 and the first rotary stage 22, and can be moved in the direction perpendicular to the paper surface by the X stage 23. In addition, the inclination of the optical axis L of the interference optical system in the plane of the paper can be adjusted by the uniaxial tilt stage 21, and the first rotary stage 22 is perpendicular to the plane of the optical axis L of the interference optical system. It is possible to adjust the rotation angle in a horizontal plane.

  The second holding means 3B side interferes with a measurement surface (measurement surface 5a in FIG. 1) of a predetermined one of the three subjects 4, 5, and 6 (subject 5 in FIG. 1). The second rotation stage 32 for rotating the subject 5 and the rotation axis R of the rotation stage 32 and the interference described above so that the interference measurement can be sequentially performed while rotating around the optical axis L of the meter body 2. The second biaxial tilt adjusting mechanism 31 and the Z stage 39 for matching the optical axis L of the meter body 2 and the second measured means on the second holding means 3B attached to the second rotary stage 32 A third biaxial tilt adjustment mechanism 33 is provided for making the surface 5a face the measured surface 4a on the interferometer body 2 side in a null state.

  The second rotary stage 32 is integrally attached to the movable plate 35 of the second biaxial tilt adjusting mechanism 31, and a light beam passage opening (see FIG. 1 (indicated by a broken line). Further, a fixed plate 38 of a third biaxial tilt adjusting mechanism 33 is attached to the surface opposite to the mounting surface with the movable plate 35, and the second rotary stage 32 rotates around the rotational axis R according to the rotation. The fixed plate 38 is also rotated. The rotation angle can be read by an angle reading mechanism (not shown) provided on the side surface of the second rotary stage 32.

  The second biaxial tilt adjusting mechanism 31 includes a support 36, a movable plate 35, an adjusting screw, and a coil spring (not shown). The movable plate 35 of the second tilt adjustment mechanism 31 to which the second rotation stage 32 is integrally attached is tilted with respect to the support 36 by rotating the adjustment screw of the second tilt adjustment mechanism 31. It is possible to adjust. This makes it possible to adjust the tilt so that the rotation axis R of the second rotation stage 32 is parallel to the optical axis L of the interferometer body 2.

  Further, the support 36 is provided with a Z stage 39, and the height of the rotation axis R of the rotary stage 32 and the optical axis L of the interferometer main body 2 can be matched. .

  The third biaxial tilt adjusting mechanism 33 includes a fixing plate 38, a holding plate 37, an adjusting screw, and a coil spring (not shown) attached to the second rotary stage 32, and the center between the fixing plate 38 and the holding plate 37. The part is provided with a light beam passage opening (indicated by a broken line in FIG. 1) similar to the light beam passage opening provided in the second rotary stage 32. Positioning pins 41 are provided at predetermined positions on the surface of the holding plate 37 opposite to the fixed plate 38. The pin 41 and the pin hole 42 of the frame 7A, 7B or 7C (7B in FIG. 1) holding the subject 4 or 5 or 6 (the subject 5 in FIG. 1) are fitted, and screws (not shown) are used. The frame 7B can be positioned and fixed to the holding plate 37. For these reasons, the measurement surface 5a of the subject 5 with respect to the measurement surface 4a of the subject 4 on the first holding means 3A side by rotating the adjustment screw of the third biaxial tilt adjustment mechanism 33. It is possible to adjust the inclination.

The above three objects 4, 5, and 6 are used as reference plates for the interferometer, and each of the measurement surfaces 4a, 5a, and 6a is a reference surface (reference) for comparison of the shape of the test plane in the interference measurement. The surface is polished with high precision so as to form a surface. The three subjects 4, 5, and 6 are attached to the frame bodies 7A, 7B, and 7C, respectively, and the flange portion 27 of the frame body holder 26 and the third two-axis are interposed through the frame bodies 7A, 7B, and 7C. The tilt adjusting mechanism 33 is held by a holding plate 37. That is, the pin 27 and the holding plate 37 are provided with two pins 41 used for alignment with the frame bodies 7A, 7B, and 7C when holding the three subjects 4, 5, and 6, respectively. Each of the frame bodies 7A, 7B, and 7C is provided with two pin holes 42 that serve as alignment indexes for engaging and aligning with the pins. The pin 41 and the pin hole 42 constitute the alignment means of the present invention. By engaging these pins with each other, the central axes C ₁ , C ₂ , C ₃ of the subjects 4, 5, 6 are arranged. However, it is configured so as to always be substantially coincident when it is attached to the flange 27 or the holding plate 37 while replacing the frames 7A, 7B, and 7C during the three-surface alignment measurement.

  Further, the uniaxial tilt stage 21, the first rotary stage 22, the X stage 23 and the first biaxial adjustment mechanism 24 provided on the first holding means 3A side, and the second holding means 3B side are provided. The second biaxial adjustment mechanism 31, the second rotary stage 32, the third biaxial adjustment mechanism 33, and the Z stage 39 provided in the present invention constitute the alignment means of the present invention. The tilt stage 21, the first rotary stage 22, the X stage 23, and the Z stage 39 constitute an axis position adjusting mechanism.

  In this embodiment, the center axis of the subject 4 or 5 or 6 (the subject 4 in FIG. 1) held by the first holding means 3A and the second holding means 3B are held by the setup procedure shown below. Alignment is performed so that the central axis of the subject 4 or 5 or 6 (subject 5 in FIG. 1) and the rotation axis R substantially coincide with the optical axis L. Moreover, in order to confirm the state where the alignment is completed, the punch pins 34 are used. The extraction pins 34, 34 are the frame bodies 7A, 7B, or 7C respectively held by the first and second holding means 3A, 3B only when the alignment is completed (the frame bodies 7A, 7B in FIG. 1). And it is comprised so that it can communicate with each extraction pin hole 43 each formed in the predetermined position of the fixing plate 38 of the said 3rd biaxial inclination adjustment mechanism 33. As shown in FIG. The movable plate 35 and the support 36 of the second biaxial inclination adjusting mechanism 31 and the holding body 37 of the third biaxial inclination adjusting mechanism 33 are allowed to pass through the extraction pin 34. An insertion hole 44 having a diameter larger than that of the punch pin hole 43 is provided.

<Setup procedure>
Hereinafter, the setup procedure of the apparatus for carrying out the three-plane alignment method will be described with a procedure number attached. In the following description, the subjects 4 and 5 are selected in the first selection operation of the three times in the three-surface alignment method, the subjects 6 and 5 are selected in the second time, and the subjects 6 and 4 are selected in the third time. A case where is selected will be described as an example. In addition, the measurement procedure by the three-plane matching method performed at each stage of the setup will be described later.

  (1) First, the subject 4 accommodated in the frame 7A is attached to the first holding means 3A side. At this time, the two pin holes 42, 42 of the frame 7A and the two pins 41, 41 provided on the flange portion 27 of the frame holder 26 on the first holding means 3A side are engaged with each other, and The measurement surface 4a of the specimen 4 is set to face the second holding means 3B side.

(2) Next, by the first 2-axis tilt adjustment mechanism 24, aligned to the center axis C ₁ and the optical axis L of the specimen 4 are substantially coincident with each other. In this alignment, a method using a corner cube (not shown) arranged on an extension line of the optical axis L (for example, on the left side of the second holding means 3B in FIG. 1) can be used. That is, first, the alignment optical system (not shown) of the interferometer body 2 is used to align the alignment spot of the measurement surface 4a with the alignment spot of the corner cube, and then the corner cube interference image is null while viewing the interference image. Adjustment by the first biaxial tilt adjustment mechanism 24 is performed so that

  (3) Next, the subject 5 accommodated in the frame 7B is attached to the second holding means 3B side. At this time, the two pin holes 42 and 42 of the frame 7B and the two pins 41 and 41 of the holding body 37 on the second holding means 3B side are engaged with each other, and the measurement surface 5a of the subject 5 is Then, it is made to face the measurement surface 4a of the subject 4 on the first holding means 3A side.

(4) After the attachment, the above-described interference is caused by the uniaxial tilt stage 21 and the first rotary stage 22 on the first holding means 3A side and the third biaxial tilt adjusting mechanism 33 on the second holding means 3B side. Using the alignment optical system of the meter body 2, the alignment spot of the measurement surface 5 a of the subject 5 matches the alignment spot of the measurement surface 4 a of the subject 4, and the central axis C _{1 of the} subject 4. to tilt adjustment so that the central axis C ₂ of the object 5 is substantially parallel to each other and. In this adjustment, the imaging optical system of the interferometer body 2 is switched from the alignment optical system to the interference image photographing optical system, and the upper part of the first holding means 3A side (interference) is viewed by the X stage 23 while viewing the screen. 1) is moved in a direction perpendicular to the paper surface of FIG. 1, and the second holding means 3B side is moved up and down by the Z stage 39 on the second holding means 3B side. for even aligned with the central axis C ₁ of the sample 4 and the central axis C ₂ of the object 5, schematically performed.

(5) Next, the second with a biaxial inclination adjustment mechanism 31, adjusted to the center axis C ₁ of the rotation axis R and the object 4 of the second rotary stage 32 is substantially parallel to each other To do. Specifically, this is performed as follows. First, the imaging optical system of the interferometer body 2 is returned to the alignment optical system, and the subject 5 is rotated by the second rotary stage 32. At this time, since the measuring surface 5a is rotated about an axis of rotation R of the rotary stage 32, when the center axis C ₁ of the subject 4 is inclined to the rotational axis R of the second rotation stage 32, The alignment spot on the surface to be measured 5a draws a circle having a diameter corresponding to the inclination without stopping at one point. The adjustment screw of the second biaxial tilt adjustment mechanism 31 may be operated so that the diameter of this circle is minimized.

(6) After the adjustment, the third biaxial tilt adjusting mechanism 33 adjusts the tilt of the central axis C ₂ of the subject 5 with respect to the second rotary stage 32, so that the central axis C ₂ of the subject 5 Alignment is performed so that the rotation axis R of the second rotation stage 32 substantially coincides with each other. Specifically, the alignment spot of the measurement surface 5a adjusted to draw the minimum diameter in the procedure of (5) above overlaps the alignment spot of the measurement surface 4a of the subject 4, and the subject 5 is rotated. Even so, the adjustment screw of the third biaxial tilt adjustment mechanism 33 may be operated so that it stops at approximately one point.

(7) above (5) and performs repeated operations (6), with the central axis C ₂ of the object 5 and the rotation axis R of the second rotary stage 32 is substantially coincide with each other, these central axes C ₂ and Adjustment is made so that the rotation axis R is substantially parallel to the central axis C ₁ of the subject 4.

  (8) After this adjustment, the second rotary stage 32 is adjusted to the initial angular position while reading the rotation angle by an angle reading mechanism (not shown).

(9) Next, the center of the subject 4 is detected by the X stage 23 and the Z stage 39 while confirming the positions of the frame bodies 7A, 7B and the fixing plate 38 using the two extraction pins 34, 34. Positioning adjustment is performed so that the axis C ₁ , the rotation axis R of the second rotation stage 32, and the center axis C ₂ of the subject 5 substantially coincide with each other. In a state where the central axis C ₁ , the central axis C ₂ and the rotation axis R are substantially coincident with each other, the two extraction pins 34 and 34 are respectively formed at predetermined positions on the frame bodies 7A and 7B and the fixing plate 38. The extraction pin hole 43 is communicated with each insertion hole 44 formed in the movable plate 35, the support 36 and the holding body 37.

  (10) After the positioning adjustment is completed, the first stage of setup is completed by removing the two extraction pins 34 and 34. After the first stage of the setup is completed, the first measurement is performed by the three-plane alignment method.

  (11) After the first measurement is completed, the X stage 23 moves the frame holder 26 on the first holding means 3A side together with the interferometer main body 2 in a direction perpendicular to the paper surface, and the subject 4 is moved to the frame 7A. It removes from the collar part 27 of the frame holder 26, storing.

(12) Next, the subject 6 accommodated in the frame 7C is attached to the first holding means 3A side. At this time, the two pin holes 42, 42 of the frame body 7C and the two pins 41, 41 of the flange portion 27 of the frame body holder 26 are engaged with each other, and the measurement surface 6a of the subject 6 is the second surface. Facing the holding means 3B side. In addition, by engaging the two pins 41 and 41 on the collar part 27 side and the two pin holes 42 and 42 on the frame body 7C side, the central axis C ₃ of the subject 6 after the exchange with respect to the collar part 27 is performed. position, substantially coincides with the position of the center axis C ₁ of the subject 4 before exchange.

(13) after mounting, by the first 2-axis tilt adjustment mechanism 24, aligned to the center axis C ₃ and the optical axis L of the subject 6 are parallel to each other. At this time, by moving the first holding means 3A side substantially to its original position by the X stage 23, for the alignment of the central axis C ₂ and the center axis C ₃ of the object 6 of the object 5, schematically To do.

(14) Next, the center of the subject 5 is detected by the X stage 23 and the Z stage 39 while confirming the position between the frame bodies 7B and 7C and the fixing plate 38 using the two extraction pins 34 and 34. Positioning adjustment is performed so that the axis C ₂ , the rotation axis R of the second rotation stage 32, and the center axis C ₃ of the subject 6 are substantially coincident with each other. In a state where the central axis C ₂ , the central axis C ₃ and the rotation axis R are substantially coincident with each other, the two extraction pins 34 and 34 are respectively formed at predetermined positions of the frame bodies 7B and 7C and the fixing plate 38. The extraction pin hole 43 is communicated with each insertion hole 44 formed in the movable plate 35, the support 36 and the holding body 37.

  (15) After the positioning adjustment is completed, the second stage of setup is completed by removing the two extraction pins 34 and 34. After the second stage of this setup is completed, the second measurement is performed by the three-plane alignment method.

  (16) After completion of the second measurement, the subject 5 is removed from the second holding means 3B side while being stored in the frame 7B.

(17) Next, the subject 4 removed after the first measurement is completed is attached to the second holding means 3B side while being accommodated in the frame body 7A. At this time, the two pin holes 42, 42 of the frame 7A and the two pins 41, 41 of the holding body 37 on the second holding means 3B side are engaged with each other, and the measurement surface 4a of the subject 4 is It is made to oppose the to-be-measured surface 6a of the subject 6. That is, the subject 4 is attached to the holding body 37 such that the subject 4 is reversed with respect to the state held on the first holding means 3A side. In addition, by engaging the two pins 41 and 41 on the holding body 37 side and the two pin holes 42 and 42 on the frame body 7A side, the central axis C of the subject 4 after the exchange with respect to the holding body 37 is performed. ₁ position, substantially coincides with the position of the center axis C ₂ before replacement of the object 5. Accordingly, at the stage when attached to the holding member 37 in a state where the frame member 7A was reversed, the central axis C ₁ of the subject 4, the center axis C ₃ axis of rotation R and the subject 6 in the second rotary stage 32 It almost matches.

(18) after mounting, by the third two-axis inclination adjustment mechanism 33, by finely adjusting the inclination of the central axis C ₁ of the subject 4, third stage set-up is completed. After the third stage of setup, the third measurement is performed by the three-plane alignment method.

<Measurement procedure by three-plane alignment method>
Hereinafter, the measurement procedure by the three-surface alignment method performed at each stage of the setup will be briefly described. In addition, the measurement procedure demonstrated below is based on the procedure of the 3 surface alignment method described in the said patent document 2. FIG.

  In the first measurement at the end of the first stage of the setup, the subject 5 is rotated around the rotation axis R by a predetermined angle by the second rotary stage 32, and the reflected light from the measurement surface 4a is By performing fringe scan measurement of interference fringes caused by optical interference with reflected light from the surface to be measured 5a and averaging the measurement results, the rotationally symmetric component of the surface to be measured 5a is relative to the surface to be measured 4a. Shape data A is obtained.

  In the second measurement at the end of the second stage of the setup, the subject 5 is rotated around the rotation axis R by a predetermined angle by the second rotary stage 32, and the reflected light from the measurement surface 6a is By performing fringe scan measurement of interference fringes caused by optical interference with reflected light from the surface to be measured 5a and averaging the measurement results, the rotationally symmetric component of the surface to be measured 5a and the surface to be measured 6a are relative to each other. Shape data B is obtained.

  In the third measurement at the end of the third stage of the setup, fringe scan measurement of interference fringes caused by optical interference between the reflected light from the measured surface 4a and the reflected light from the measured surface 6a is performed. Relative shape data C between the measured surface 6a and the inverted measured surface 4a is obtained.

  Next, the measurement surface 4a was inverted in the arithmetic unit with respect to the data A of the relative shape between the rotationally symmetric component of the measurement surface 5a and the measurement surface 4a obtained in the first measurement. In this way, the coordinate conversion process for converting the coordinates is performed to obtain the relative shape data A ′ between the rotationally symmetric component of the surface to be measured 5a and the surface to be measured 4a that is inverted in software.

  Thereafter, (data A′−data C + data B) / 2 is calculated to obtain shape data of the rotationally symmetric component of the measured surface 5a. The absolute shape data of the measured surfaces 4a and 6a is obtained based on the shape data of the rotationally symmetric component of the measured surface 5a, and the absolute shape data of the measured surface 5a is obtained from the data.

  In the above embodiment, the plane reference plate is the subject. However, even when the reference lens for optical interference measurement of the curved surface shape is the subject, the first holding means 3A and the second holding unit 3A are used. The present invention can be similarly applied by adding a one-axis moving stage capable of moving the test surface along the optical axis L to one or both of the holding means 3B.

1 is a schematic configuration diagram of an interferometer apparatus provided with a subject installation apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Interferometer apparatus 2 Interferometer main-body part 3 Object installation apparatus 3A 1st holding means 3B 2nd holding means 4, 5, 6 Subject 4a, 5a, 6a Measuring surface 7A-7C Frame 21 Uniaxial inclination Stage 22 First rotary stage 23 X stage 24 First biaxial tilt adjusting mechanism 25 Fringe scan adapter 26 Frame holder 27 Hook 31 Second biaxial tilt adjusting mechanism 32 Second rotary stage 33 Third 2 axis tilt adjustment mechanism 34 core pin 35 movable plate 36 support 37 support frame 38 fixed plate 39 Z stage 41 pin 42 pin holes 43 discharge pin hole 44 through hole L optical axis R rotational axis C ₁ -C ₃ central axis

Claims (3)

A predetermined two of three subjects having measurement surfaces having substantially the same shape as each other are sequentially selected three times by changing the combination, and each time the selection operation is performed, the two selected subjects are The measurement surfaces are arranged so as to oppose each other at a predetermined interval at two predetermined positions on the optical axis of the interference optical system, and the relative displacements of these opposing measurement surfaces are measured two-dimensionally. In the subject placement apparatus for performing a three-surface alignment method for calculating the measurement result of three times to obtain the shape of the measurement surface of each subject,
First holding means for holding one of the two subjects selected by the selection operation at one of the two positions;
Second holding means for holding the other of the two subjects selected by the selection operation so as to be rotatable around a predetermined rotation axis in the other of the two positions;
When the subject held by the first and / or second holding means is exchanged with another subject, the positions of the central axes of the subjects before and after the exchange with respect to the holding means are substantially the same. Alignment means for matching;
Alignment means for causing the central axis of the subject held by the first holding means, the central axis of the subject held by the second holding means, and the rotation axis to substantially coincide with the optical axis; equipped with a,
The alignment means includes a first biaxial tilt adjustment mechanism that makes the central axis of the subject held by the first holding means substantially parallel to the optical axis, and the rotation axis substantially parallel to the optical axis. A second biaxial tilt adjusting mechanism that makes the center axis of the subject held by the second holding means substantially parallel to the rotating shaft, and the rotating shaft An axis position adjusting mechanism that substantially matches the position of the optical axis with the position of the optical axis ,
The three subjects are configured to be held by the first and second holding means via the respective frames attached to these subjects,
In each of the two predetermined positions of the frame and the fixing plate of the third biaxial inclination adjusting mechanism, each extraction pin hole through which two extraction pins for positioning adjustment are respectively communicated is formed.
Each frame attached to each of these subjects only when the alignment between the subject held by the first holding means and the subject held by the second holding means is completed. A subject placement apparatus characterized in that the two extraction pins can be communicated with each extraction pin hole of the body and the fixing plate of the third biaxial tilt adjustment mechanism . Before Symbol alignment means, wherein for the positioning of the frame member and the first and / or second retaining means when the subject is exchanged to the other object, these retaining means and the frame claim 1 Symbol placement subject installed device is characterized in that it comprises an alignment indicator respectively provided. Wherein an interferometer body portion having said interference optical system, and the object placing device according to claim 1 or 2, to become an arithmetic unit for implementing a predetermined operation in the three planes combined method Interferometer device.

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