JP2004077308A - Three-dimensional shape measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly accurately adjust the temperature of only necessary portions of a measuring instrument even if it is an upsized one, without preparing a large-scaled temperature conditioning device. <P>SOLUTION: This three-dimensional measuring instrument mounted with a non-contact or contact type probe has the function of partially adjusting the temperature of only the interior of a reference mirror box of a laser end-measuring machine for measuring the position of a probe axis and necessary portions of a work stocker. An air duct for partial air adjustment has a double structure so as not to mix in external air. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a three-dimensional shape measuring apparatus for measuring the three-dimensional shape of a measurement object such as an aspherical surface, a spherical surface, or a lens having a free-form surface, a mold, or a molded product with high accuracy, and is particularly used for a semiconductor manufacturing apparatus. The present invention relates to a three-dimensional shape measuring apparatus that measures a surface shape of a measurement object that requires a highly accurate surface shape such as an imaging lens.
[0002]
[Prior art]
Conventionally, Japanese Patent Application Laid-Open No. 2001-88512 has been disclosed as a temperature control method of a measuring device for performing highly accurate three-dimensional surface shape measurement. FIG. 6 shows a conventional three-dimensional shape measuring apparatus. In FIG. 6, the Fizeau surface and the surface to be measured are arranged in a constant temperature chamber 1015. The light emitted from the interferometer 1011 is applied to the reference surface 1012a and the test surface 1013a, and the reflected lights interfere with each other to generate interference fringes. The surface shape of the test object 1013 is measured by measuring the fringes and analyzing the fringes by the arithmetic device 1021. At this time, the movement of the test object necessary for the measurement, that is, the movement in the optical axis direction, the movement in the direction perpendicular to the optical axis, and the inclination correction with respect to the optical axis are all automatically performed from outside the constant temperature chamber. In FIG. 6, reference numeral 1101 denotes a chuck having a rotation axis, which is movable in the axial direction, chucks an object to be measured from an object stand 1017 for storing an unmeasured object, and measures the position. Has the role of setting This enables the setting of the test object from outside the chamber. Reference numerals 1041a to 1041n denote temperature sensors for measuring the temperature in the chamber and its distribution, the output of which is given to the controller 1042, and the controller 42 controls the temperature in the chamber to be a uniform constant temperature. When the measurement of the test object on the test object stand is completed, the test object is replaced with the test object stored in the next test object stand 1018 by opening and closing the door 1031.
[0003]
[Problems to be solved by the invention]
The conventional example shown in FIG. 6 has been devised so that a high-precision measurement with little temperature change can be performed by installing a measuring instrument main body and a plurality of unmeasured objects in a temperature-controlled chamber. However, in this method, since the main body and a plurality of unmeasured objects are placed in the same temperature-controlled chamber, that is, in a constant temperature chamber, the size of the constant temperature chamber increases. When the constant temperature chamber becomes large, it becomes very difficult to keep the temperature inside the constant temperature chamber constant, it is very difficult to control the same temperature in each part in the constant temperature chamber, and the equipment for temperature control also becomes large. Such a problem occurs.
[0004]
The present invention has been devised to solve such a problem, and enables high-precision temperature control even in a large-sized constant-temperature chamber by installing a measuring apparatus main body and a plurality of unmeasured objects in the constant-temperature chamber. This is a three-dimensional shape measuring apparatus for performing a three-dimensional shape measurement with high accuracy in an atmosphere having a very small temperature change.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the three-dimensional shape measuring apparatus of the present invention is equipped with a contact-type or non-contact-type probe, and measures the three-dimensional shape by scanning the surface of an object to be measured with the probe. In the measuring apparatus, a laser interferometer for measuring the position of the probe, a reference mirror, and a part to be measured are partially air-conditioned.
[0006]
A contact or non-contact probe is mounted on a stage movable in the Z-axis direction, the Z-axis is mounted on a Y-axis slide movable in the Y-axis direction, and the Y-axis slide is mounted on the X-axis direction. Mounted on a movable X-axis slide, the Z-axis slide, the Y-axis slide, and the X-axis slide have moving axes arranged so as to be orthogonal to each other, and as a measurement unit for detecting the position of the probe, A Z-axis reference mirror for detecting the Z-axis position of the probe, a Y-axis reference mirror for detecting the Y-axis position of the probe, and an X-axis reference for detecting the X-axis position of the probe A box-shaped structure having a mirror, the Z-axis reference mirror, the Y-axis reference mirror, and the X-axis reference mirror arranged on an inner surface, and scanning the surface of the object by the probe to form a three-dimensional shape. To In the three-dimensional shape measuring device for constant, characterized by partial air-conditioning the inside only of the box-like structure.
[0007]
Further, the three-dimensional shape measuring apparatus of the present invention includes a stocker for stocking a plurality of the object to be measured, an automatic mounting mechanism for automatically mounting the object to be measured on a measuring table of the three-dimensional measuring apparatus, It has a cover that covers one or more of the stockers, and only the inside of the cover of the stocker is partially air-conditioned.
[0008]
Further, the air conditioning duct through which the temperature control air flows for performing the partial air conditioning has a double structure.
[0009]
Further, the three-dimensional shape measuring apparatus of the present invention includes two sets of the contact-type probes, the two sets of probes are arranged to face each other, and are mounted on a Z-axis stage movable independently in the Z-axis direction. By individually tracing opposing surfaces of an object to be measured disposed between the two sets of probes, mutually opposing surface shapes of the object to be measured are simultaneously measured.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0011]
(Example)
FIG. 1 is a plan view of a high-precision three-dimensional shape measuring apparatus according to the present invention, which has a function of air-conditioning a part of the three-dimensional shape measuring apparatus with high accuracy, and FIG. , FIG. 1 as viewed from the AA direction, and FIG. 3 is a side view of the same, and FIG. 1 as viewed from the BB direction.
[0012]
In FIGS. 1, 2 and 3, reference numeral 101 denotes a gantry for supporting the measurement main body. 104a, 104b and 104c are vibration isolation tables, and the gantry 101 is mounted on the vibration isolation tables 104a, 104b and 104c. Reference numeral 108a denotes an upper probe arm on which a probe unit 203a for measuring the upper surface of the DUT 109 is mounted. Reference numeral 107a denotes an upper Z axis for moving the upper probe arm 108a in the Z direction. In the present invention, a linear air bearing is used for the Z axis guide and a linear motor is used for driving. Reference numeral 108b denotes a lower probe arm on which a probe unit 203b for measuring the lower surface of the device under test 109 is mounted. Reference numeral 107b denotes a lower Z axis for moving the lower probe arm 108b in the Z direction. In the present invention, a linear air bearing is used for the Z axis guide and a linear motor is used for driving. Steel balls are attached to the tips of the upper surface measurement probe unit 203a and the lower surface measurement probe unit 203b by vacuum suction. As the steel ball, a steel ball having good sphericity or a ruby ball is generally used. Reference numeral 106 denotes a main body Y-axis that moves the upper Z-axis 107a and the lower Z-axis 107b in the horizontal direction, that is, the Y direction. In the present invention, a linear air bearing is used for the guide of the main body Y-axis, and a linear motor is used for driving. I have.
[0013]
Reference numeral 105 denotes a main body X-axis for moving the main body Y-axis 106 in a direction orthogonal to the Y-axis, that is, in the X-axis direction. In the present invention, a rolling bearing is used as a guide for the main body X-axis, and a ball screw feed by a servomotor is used for driving. are doing. The upper measuring probe unit 203a and the lower surface mounted on the upper probe arm 108a and the lower probe arm 108b by driving the upper Z axis 107a, the lower Z axis 107b, the main body Y axis 106, and the main body X axis 105 as described above. The contact probe tip sphere of the measurement probe unit 203b can scan the upper surface and the lower surface of the measured object 109 simultaneously on both surfaces or one by one. Reference numeral 103 denotes reference mirrors 202a, 202b, 202c, 202d, 202e, and 202f serving as references for a laser length measuring device (not shown) for measuring the positions of the probe units mounted on the upper probe arm 108a and the lower probe arm 108b. It is a mirror box with attached. The mirror box 103 is attached to the gantry 101 via the column 201 and the work mounting table 119, and the mirror box 103 is received at three points by kinematic support with respect to the work mounting table 119. The mirror box 103 is supported so as not to be deformed by the deformation of the stand 119. The mount 101 on which the mirror box 103 and the column 201 are mounted is separated from the Z-axis 107a, 107b, the main body Y-axis 106, and the main body X-axis 105. The structure does not directly transmit to the mirror box 103 through the gantry 101.
[0014]
Reference numeral 110 denotes a work stocker which can prepare a plurality of objects to be measured before measurement, and controls the temperature until the measurement order comes. Reference numeral 125 denotes a work stocker air conditioning duct for covering one or more unmeasured works mounted on the work stocker 110 and partially air-conditioning the work.
[0015]
In the present invention, the constant temperature chamber 111 is divided into two chambers by a partition 113, 126 is a work stocker room in which the work stocker 110 and the like are installed, and 127 is a measuring device main body room in which the measuring device main body is set. Reference numeral 117 denotes an object to be measured before measurement. The object to be measured is sent forward by the work stocker 110 to the measuring apparatus main body side, and when the object to be measured is transferred to a position 117b, which is a portion covered by the work stocker air conditioning duct 125, a more accurate temperature control is performed before the measurement. Is applied to the device under test. The DUT before measurement is sent to the position 123 by the switching device 122. During this time, high-precision temperature control is continuously performed on the object to be measured. Therefore, the size of the high-precision temperature control region is determined by the measurement tact and the time required for the temperature control, and a minimum necessary region may be secured. Thereafter, it is sent into the main body of the measuring apparatus by the automatic hand 120, and is positioned at the position of the object to be measured 109 by the retracting device 121. At this time, the retracting device 121 performs the positioning so that an impact at the time of positioning is not applied to the object 109 to be measured. When the measurement is completed, it is pulled out of the measuring apparatus main body by the automatic hand 120 and sent to the measurement end position 118 by the work stocker 110. During this time, the movement of the device under test is automatically performed by a command from a computer or an NC controller (not shown). Therefore, there is no need for a person to approach the measuring device every time the device under test is replaced. Reference numeral 111 denotes a constant temperature chamber, and 112 denotes a constant temperature chamber control room. Reference numeral 113 denotes a partition for dividing the constant temperature chamber 111 into a measuring device main body side and a work stocker side. The purpose is to reduce the volume of the constant temperature chamber on the measuring main body side to perform more precise temperature control. In this way, after a plurality of objects to be measured are mounted on the work stocker 110, all the measurements can be performed automatically, so that there is no need for a person to enter the constant temperature chamber 111, and high-precision measurement is performed with less temperature change. I can do it.
[0016]
Reference numeral 114 denotes a damper inserted between the gantry 101 and the column 201 to absorb vibration of the column 201 with respect to the gantry 114. Reference numeral 102 denotes a unit for automatically exchanging tip balls adsorbed on the tips of the upper surface measurement probe unit 203a and the lower surface measurement probe unit 203b. Reference numeral 124 denotes a mirror box air-conditioning duct for partially air-conditioning the inside of the mirror box 103. Reference numeral 124b denotes an upper mirror box air-conditioning duct that sends air conditioned to a space in the mirror box duct 124 in which the upper surface measurement probe unit 203a moves, and 124a denotes an upper mirror box disposed outside the upper mirror box air-conditioning duct 124b. Cover air conditioning duct. That is, the upper mirror box air conditioning duct 124b and the upper mirror box cover air conditioning duct 124a form a duplex duct. Reference numeral 124d denotes a lower mirror box air-conditioning duct for feeding air-conditioned air to the space in which the lower surface measurement probe unit 203b moves in the mirror box duct 124, and 124c denotes a lower side arranged outside the lower mirror box air-conditioning duct 124d. It is a cover air conditioning duct for the side mirror box. In other words, the lower mirror box air conditioning duct 124d and the lower mirror box cover air conditioning duct 124c form a duplex duct.
[0017]
Reference numeral 301 denotes a space surrounded by the upper reference mirrors 202a, 202b, and 202e of the mirror box 103 and the upper side of the DUT 109 or the work mounting table 119, and 302 denotes a space surrounded by the lower reference mirror 202c of the mirror box 103. The space surrounded by 202 d and 202 f and the object to be measured 109 or the lower side of the work mounting table 119 is shown. Reference numeral 303 denotes an upper duct port for inserting the upper mirror box air conditioning duct 124b of the mirror box 301, and reference numeral 304 denotes a lower duct port for inserting the lower mirror box air conditioning duct 124d of the mirror box 301.
[0018]
Next, the function of the partial air conditioning will be described with reference to FIG. The main body X-axis 105, the main body Y-axis 106, and the upper Z-axis 107a are driven in accordance with instructions from a computer or an NC controller (not shown), and the top surface of the DUT 109 is moved with a tip ball attached to the tip of the top measurement probe unit 203a. Scan by scanning. At this time, the upper reference mirror 202a in the upper space 301 is formed by the upper surface measurement probe unit 203a or the laser interferometer (not shown) mounted on the upper probe arm 108a on which the upper surface measurement probe unit is mounted. The distance from 202b, 202e is measured. In this way, the trajectory coordinates when the position of the tip sphere of the upper surface measurement probe unit 203a scans along the upper surface of the measured object 109 are obtained. That is, the shape of the upper surface of the DUT 109 is measured.
[0019]
At this time, if the temperature in the upper space 301 fluctuates due to a temperature change due to the influence of disturbance, the shape of the object to be measured 109 changes, or the upper surface measurement probe unit expands and contracts, an error occurs in the measurement result. Will occur. In the present invention, the upper surface measurement probe unit 203a or the laser interferometer (not shown) mounted on the upper probe arm 108a on which the upper surface measurement probe unit is mounted is connected to the upper space 301, that is, the mirror box 103. Focusing on the relatively closed and narrow space between the upper reference mirrors 202a, 202b, 202e and the DUT 109, the upper space 301 is supplied with high-precision controlled air at a constant temperature for the upper mirror box. The temperature is controlled to be constant by being sent in by the air conditioning duct 124b. At this time, if the temperature-controlled air is simply sent into the upper space 301, the upper duct port 303 and the upper mirror box air-conditioning duct 124b may be connected without any gap, but the duct through which the air passes generally vibrates. In many cases, when the upper mirror box air conditioning duct 124b is connected to the upper duct port 303, the vibration of the upper mirror box air conditioning duct 124b is transmitted to the mirror box 103, and the upper reference mirrors 202a, 202b, and 202e, which are the measurement reference, vibrate. This causes an error in the measurement. Therefore, it is better not to connect the upper mirror box air conditioning duct 124b to the upper duct port 303. However, if the upper mirror box air conditioning duct 124b is not connected to the upper duct opening 303, a gap is formed between the upper mirror box air conditioning duct 124b and the upper duct 303. In this state, the upper mirror box air conditioning duct 124b moves to the upper space 301. When the temperature-controlled air is sent, air outside the mirror box 103 is entrained from the gap between the upper mirror box air conditioning duct 124b and the upper duct opening 303 and flows into the upper space 301.
[0020]
FIG. 5 shows a state in which air outside the mirror box 103 is caught and flows into the upper space 301. In FIG. 5, reference numeral 501 denotes a flow of air from outside the mirror box 103, and reference numeral 402 denotes a flow of temperature-regulated air from the upper mirror box air conditioning duct 124b.
[0021]
Thus, in the present invention, the upper mirror box cover air conditioning duct 124a is arranged outside the upper mirror box air conditioning duct 124b, and the air conditioning duct has a double structure. At this time, the upper mirror box cover air-conditioning duct 124 a is arranged so as not to enter the upper space 301 from the upper duct port 303 and to be opened outside the mirror box 103. By passing high-precision air through the upper mirror box air conditioning duct 124b and the upper mirror box cover air conditioning duct 124a arranged as described above, a gap between the upper mirror box air conditioning duct 124b and the upper duct opening 303 is provided. Is applied with air pressure from the upper mirror box cover air conditioning duct 124a, so that air outside the mirror box 103 is caught in the gap between the upper mirror box air conditioning duct 124b and the upper duct port 303 and flows into the upper space 301. Will not be lost. Therefore, it is possible to control the temperature of the space 301 above the mirror box 103 with high accuracy.
[0022]
FIG. 4 shows how the temperature-controlled air flows from the upper mirror box air conditioning duct 124b and the upper mirror box cover air conditioning duct 124a. In FIG. 4, reference numeral 401 denotes a flow of temperature-controlled air from the upper mirror box cover air conditioning duct 124a, and reference numeral 402 denotes a temperature-controlled air flow from the upper mirror box air conditioning duct 124b. As shown in FIG. 4, there is no possibility that air outside the mirror box 103 is caught in the gap between the upper mirror box air conditioning duct 124b and the upper duct opening 303 and flows into the upper space 301.
[0023]
Similarly, a lower mirror box cover air conditioning duct 124c is arranged outside the lower mirror box air conditioning duct 124d, and the air conditioning duct has a double structure. At this time, the lower mirror box cover air conditioning duct 124c is arranged so as not to enter the lower space 302 from the lower duct opening 304 and to be opened outside the mirror box 103. By passing high-precision air through the lower mirror box air conditioning duct 124d and the lower mirror box cover air conditioning duct 124c arranged as described above, the lower mirror box air conditioning duct 124d and the lower duct are formed. Since air pressure from the lower mirror box cover air conditioning duct 124c is applied to the gap between the ports 304, air outside the mirror box 103 is entrained from the gap between the lower mirror box air conditioning duct 124d and the lower duct port 304. It does not flow into the lower space 302. Therefore, it is possible to control the temperature of the space 302 below the mirror box 103 with high accuracy.
[0024]
In the present invention, the work stocker room 126 is set to ± 0.03 ° C., the measuring device main unit room is set to ± 0.02 ° C., the workpiece at the position 117b is set to ± 0.01 ° C. by the work stocker air conditioning duct 125, and the upper mirror is set. The inside of the space 301 above the mirror box 103 is set to ± 0.01 ° C. by the temperature-controlled air from the box air conditioning duct 124b and the upper mirror box cover air conditioning duct 124a, and the lower mirror box air conditioning duct 124d and the lower mirror. The temperature in the space 302 below the mirror box 103 is adjusted to ± 0.01 ° C. by the temperature control air from the box cover air conditioning duct 124c.
[0025]
As described above, the upper space 301 and the lower space 302 in the mirror box 103 in the measurement device main body, and the high-precision temperature control portion 117b of the work stocker 110 are heated more accurately than the work stocker room 126 and the measurement device main room 127. It is desirable to adjust.
[0026]
【The invention's effect】
As described above, according to the present invention, in a three-dimensional shape measuring apparatus that measures a lens surface shape of a high-precision imaging lens used for a stepper or the like by non-contact or by scanning with a contact probe, The laser interferometer and the reference mirror for measuring the position of the object and the part of the object to be measured are partially air-conditioned with high accuracy, and a stocker for storing a plurality of the objects to be measured is provided automatically. Has an automatic mounting mechanism for mounting on the measuring table of the three-dimensional measuring device, and a cover that covers one or more of the stockers, and partially air-conditions only the inside of the cover of the stocker with a high degree of accuracy in measuring accuracy. Since the temperature of a portion necessary for stabilizing the temperature can be controlled, it is not necessary to control the temperature of the entire measuring device body with high accuracy. Therefore, there is no need to precisely control the temperature over a wide range, so that the temperature control equipment can be downsized and the accuracy of the temperature control can be improved.
[0027]
In addition, the air conditioning duct for partial temperature control has a double structure, so that air whose temperature has been precisely controlled can be sent into the target space without entraining outside air. improves.
[Brief description of the drawings]
FIG. 1 is a plan view of a contact type three-dimensional shape measuring device embodying the present invention. FIG. 2 is a side view of a contact type three-dimensional shape measuring device embodying the present invention. FIG. Side view of the mirror box part of the original shape measuring device [Fig. 4] Description of operation when the air conditioning duct for partial temperature adjustment has a double structure [Fig. 5] Illustration of the air conditioning duct for partial temperature adjustment having a single-layer structure [ FIG. 6 is a plan view of a conventional measuring device.
101 Mounts 104a, 104b, 104c Vibration isolation table 108a Upper probe arm 107a Upper Z axis

Claims (5)

A laser interferometer for measuring a position of the probe in a three-dimensional shape measuring device equipped with a contact type or non-contact type probe and measuring a three-dimensional shape by scanning a surface of an object to be measured with the probe. A three-dimensional shape measuring device for partially air-conditioning a reference mirror and an object to be measured. A contact-type or non-contact type probe is mounted on a stage that can move in the Z-axis direction. The Z-axis is mounted on a Y-axis slide that can move in the Y-axis direction. The Y-axis slide can move in the X-axis direction. The Z-axis slide, the Y-axis slide, and the X-axis slide have moving axes arranged so as to be orthogonal to each other, and as a measuring means for detecting the position of the probe, A Z-axis reference mirror for detecting a Z-axis position, a Y-axis reference mirror for detecting a Y-axis position of the probe, and an X-axis reference mirror for detecting an X-axis position of the probe. It has a box-shaped structure in which the Z-axis reference mirror, the Y-axis reference mirror, and the X-axis reference mirror are arranged on the inner surface, and measures the three-dimensional shape by scanning the surface of the object to be measured with the probe. You In the three-dimensional shape measuring apparatus, the three-dimensional shape measuring apparatus characterized by partial air-conditioning the interior of the box-like structure. A stocker for storing a plurality of the objects to be measured is provided, and an automatic mounting mechanism for automatically mounting the object to be measured on the measuring table of the three-dimensional measuring device, and a cover covering one or more of the stockers are provided. The three-dimensional shape measuring apparatus according to claim 1, wherein only the inside of the cover of the stocker is partially air-conditioned. The three-dimensional shape measuring apparatus according to any one of claims 1 to 3, wherein an air-conditioning duct through which temperature-regulated air for performing the partial air-conditioning is formed has a double structure. The apparatus has two sets of the probes, the two sets of probes are arranged opposite to each other, mounted on a Z-axis stage that is independently movable in the Z-axis direction, and a measured object is arranged between the two sets of probes. The three-dimensional structure according to any one of claims 1 to 4, wherein the mutually opposed surface shapes of the object to be measured are simultaneously measured by individually tracing the mutually opposed surfaces of the object. Shape measuring device.

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