Three-dimensional shape measuring device and method for adjusting the position of its reference surface

Abstract

To provide a three-dimensional shape measuring device that can match a measured optical path length and a reference optical path length with each other with high accuracy at low cost regardless of the temperature of an installation environment, and a reference surface position adjustment method for the same.SOLUTION: A three-dimensional shape measuring device comprises: a light source unit that emits measuring light being white light; an interference unit that divides part of the measuring light emitted by the light source unit as reference light, emits the measuring light to a surface to be measured and emits the reference light to a reference surface, and generates interference light between the measuring light returning from the surface to be measured and the reference light returning from the reference surface; a holder that accommodates the interference unit and the reference surface, the holder formed of a material that is thermally deformed reversibly according to a change in temperature and changing a reference optical path length that is the optical path length of the reference light between the interference unit and the reference surface according to the change in temperature; and a temperature adjustment unit that, when the optical path length between the interference unit and the surface to be measured is a measured optical path length, adjusts the temperature of the holder to be a target temperature at which the reference optical path length matches the measured optical path length.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a three-dimensional shape measurement apparatus that measures the three-dimensional shape of a measurement surface using a white light interference method and a method for adjusting the position of a reference surface thereof.

Background Art

[0002] There is known a method of optically measuring three-dimensional shapes such as an all-focus image, a surface shape, and a surface roughness shape of a measurement surface of a measurement object using a three-dimensional shape measurement apparatus of a white light interference method (White Light Interferometry: WLI) described in Non-Patent Document 1 and Patent Document 1.

[0003] A three-dimensional shape measurement apparatus of the WLI method includes a white light interference microscope including a light source, an interference unit, an objective lens, and a camera, a drive mechanism, a camera, and a control device. The light source emits white light toward the interference unit. The interference unit divides a part of the white light emitted from the light source as reference light, emits the remaining white light to the measurement surface, and emits the reference light to the reference surface. Further, the interference unit emits interference light between the white light reflected by the measurement surface and the reference light reflected by the reference surface toward the camera.

[0004] The focus of the objective lens is adjusted to the measurement surface by known focusing control, and condenses white light before division (for example, Michelson type) or after division (for example, Linnik type) by the interference unit on the measurement surface. The drive mechanism scans the interference unit or the white light interference microscope along the scanning direction (vertical direction). The camera continuously captures the interference light emitted from the interference unit during the scanning of the interference unit and the like by the scanning mechanism, and acquires a plurality of images including interference fringes. The control device measures the three-dimensional shape of the measurement surface by comparing the luminance values of pixels at the same coordinates of each image and calculating the height information of the measurement surface for each pixel.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] [Non-Patent Document 1] ISO 25178-604:2013”Geometrical product specifications (GPS) - Surface texture: Area-Part 604: Nominal characteristics of non-contact (coherence scanning interferometry) instruments” [Overview of the project] [Problems that the invention aims to solve]

[0007] Figures 13 to 15 are explanatory diagrams illustrating the challenges of conventional white-light interference microscopes, which constitute three-dimensional shape measuring devices. Here, a Michelson-type white-light interference microscope is used as an example.

[0008] As shown by the symbol XIIIA in Figure 13, at least the interference objective lens 500, interference section 501, reference plane 502, and objective lens 504 of the white light interference microscope are housed in a holder 506 made of a metal material such as brass. When measuring the three-dimensional shape of the surface to be measured W, the focus of the objective lens 504 is aligned with the surface to be measured W, and the reference optical path length D2, which is the optical path length of the reference light L2 between the interference section 501 and the reference plane 502, is matched to the measurement optical path length D1, which is the optical path length of the measurement light L1 between the interference section 501 and the surface to be measured W. As a result, interference fringes are generated in the interference light L3 emitted from the interference objective lens 500, making it possible to measure the three-dimensional shape of the surface to be measured W.

[0009] In this process, the holder 506, which is made of brass or the like, undergoes reversible thermal deformation (expansion and contraction) in response to changes in the ambient temperature. As a result, as shown by the symbols XIIIB in Figure 13 and XIVA in Figure 14, if the holder 506 expands due to thermal expansion, the reference optical path length D2 changes, causing a mismatch between the measured optical path length D1 and the reference optical path length D2. Consequently, the generation of interference fringes in the interference light L3 is suppressed, making it difficult to measure the three-dimensional shape of the surface W to be measured.

[0010] Therefore, as shown by the symbol XIVB in Figure 14, it is conceivable to change the distance between the holder 506 (interference objective lens 500) and the surface to be measured W, i.e., change the measurement optical path length D1, in order to match the measurement optical path length D1 with the reference optical path length D2 which has changed due to the thermal expansion of the holder 506. However, if the measurement optical path length D1 is changed, the focus of the objective lens 504 will no longer be aligned with the surface to be measured W. If the three-dimensional shape of the surface to be measured W is measured in this state, as shown in Figure 15, the measured shape (see symbol XVB) will be distorted relative to the actual shape of the surface to be measured W (see symbol XVA), resulting in a decrease in measurement accuracy. In addition, the intensity of the interference light incident on the camera decreases, making it impossible to measure the three-dimensional shape of the surface to be measured W or reducing the measurement accuracy.

[0011] Therefore, the holder 506 is equipped with a reference surface position adjustment mechanism that allows for manual adjustment of the position of the reference surface 502. Depending on the ambient temperature in which the white light interference microscope is installed, the operator manually adjusts the position of the reference surface 502 by operating the reference surface position adjustment mechanism so that the reference optical path length D2 matches the measured optical path length D1. As a result, the accuracy, adjustment resolution, and reproducibility of the position of the reference surface 502 were low, and this further hindered the efficiency (automation) of three-dimensional shape measurement of the surface W to be measured.

[0012] Furthermore, in order to adjust the position of the reference plane 502 using the reference plane position adjustment mechanism so that the reference optical path length D2 matches the measurement optical path length D1, a highly accurate reference plane position adjustment mechanism is required. For example, assuming that the numerical aperture (NA) of the objective lens 504 is 0.7 and the wavelength of the measurement light L1 is 550 nm, the depth of field (DOF) of the objective lens 24a is "DOF = λ / (2 × (NA) 2 This results in a resolution of 0.56 μm. In this case, the reference plane position adjustment mechanism requires a control resolution significantly smaller than 0.56 μm, which would drastically increase costs.

[0013] This invention has been made in view of these circumstances, and aims to provide a three-dimensional shape measuring device that can accurately match the measured optical path length and the reference optical path length at low cost, regardless of the ambient temperature of the installation environment, and a method for adjusting the position of its reference surface. [Means for solving the problem]

[0014] A three-dimensional shape measuring apparatus for achieving the object of the present invention comprises: a light source unit that emits measuring light which is white light; an interference unit that splits a portion of the measuring light emitted from the light source unit as reference light, emits the measuring light to the surface to be measured and emits the reference light to the reference surface, and generates interference light between the measuring light returning from the surface to be measured and the reference light returning from the reference surface; a holder that houses the interference unit and the reference surface, which is made of a material that reversibly deforms with heat in response to temperature changes, and changes the reference optical path length, which is the optical path length of the reference light between the interference unit and the reference surface, in response to temperature changes; and a temperature adjustment unit that adjusts the temperature of the holder to a target temperature where the reference optical path length matches the measuring optical path length, when the optical path length of the measuring light between the interference unit and the surface to be measured is set as the measuring optical path length.

[0015] This three-dimensional shape measuring device allows the reference optical path length to be precisely matched to the measured optical path length by adjusting the temperature of the holder.

[0016] In another aspect of the present invention, a three-dimensional shape measuring apparatus includes: a temperature measuring unit for measuring the temperature of a holder; an objective lens for focusing measurement light onto the surface to be measured; a camera for imaging the interference light generated by an interference unit; a provisional target temperature control unit for controlling a temperature adjustment unit to adjust the temperature of the holder to a predetermined provisional target temperature; a focusing control unit for aligning the focus of the objective lens with the surface to be measured; and a reference surface position adjustment mechanism that, when the holder is adjusted to the provisional target temperature and the focus of the objective lens is aligned with the surface to be measured, accepts manual adjustment of the position of the reference surface and adjusts the reference optical path length to roughly match the measurement optical path length. The system includes a temperature change control unit that controls the temperature adjustment unit to change the holder temperature while the illuminated optical path length is approximately equal to the measured optical path length; an image acquisition unit that causes a camera to repeatedly capture interference light and acquires multiple images from the camera while the temperature change control unit is changing the holder temperature; a temperature acquisition unit that acquires the temperature measurement result from the temperature measurement unit each time the camera captures interference light; and a target temperature determination unit that determines the temperature at which the intensity of the interference fringes is maximized as the target temperature, based on the multiple images acquired by the image acquisition unit and the temperature measurement result acquired by the temperature acquisition unit for each image. This makes it possible to match the measured optical path length and the reference optical path length with high accuracy at low cost.

[0017] In another aspect of the present invention, a three-dimensional shape measuring apparatus comprises: a temperature measuring unit for measuring the temperature of a holder; an objective lens for focusing measurement light onto the surface to be measured; a camera for capturing interference light generated by an interference unit; a focusing control unit for adjusting the focus of the objective lens to the surface to be measured; a temperature change control unit for controlling a temperature adjustment unit to change the temperature of the holder while the focus of the objective lens is aligned with the surface to be measured; an image acquisition unit for repeatedly having the camera capture interference light and acquiring multiple images from the camera while the temperature change control unit is changing the temperature of the holder; a temperature acquisition unit for repeatedly acquiring the temperature measurement results of the temperature measuring unit while the temperature change control unit is changing the temperature of the holder; and a target temperature determination unit for determining the temperature at which the intensity of the interference fringes is maximized as the target temperature, based on the multiple images acquired by the image acquisition unit and the multiple temperature measurement results acquired by the temperature acquisition unit for each image. This enables the determination of the target temperature to be automated.

[0018] In a three-dimensional shape measuring apparatus according to another aspect of the present invention, a temperature measuring unit that measures the temperature of the holder, and a target temperature control unit that controls a temperature adjusting unit based on a target temperature and the temperature measurement result of the temperature measuring unit to adjust the temperature of the holder to the target temperature are provided. Thereby, the temperature of the holder can be accurately adjusted and maintained at the target temperature.

[0019] In a three-dimensional shape measuring apparatus according to another aspect of the present invention, the temperature adjusting unit changes the temperature of a reference surface storage unit that stores a reference surface in the holder, and the temperature measuring unit measures the temperature of the reference surface storage unit. Thereby, the reference optical path length can be adjusted by controlling the temperature of the holder.

[0020] In a three-dimensional shape measuring apparatus according to another aspect of the present invention, a heat insulating material that covers at least the reference surface storage unit, the temperature measuring unit, and the temperature adjusting unit is provided. Thereby, the temperature of the reference surface storage unit and its vicinity can be stabilized.

[0021] In a three-dimensional shape measuring apparatus according to another aspect of the present invention, a target temperature storage unit that stores the correspondence relationship between an adapter unit to which a plurality of lens systems including a holder, a temperature adjusting unit, and a temperature measuring unit are selectively attached, the plurality of lens systems, and a target temperature determined for each lens system, a lens system discrimination unit that discriminates the lens system attached to the adapter unit, and a target temperature acquisition unit that acquires the target temperature corresponding to the lens system attached to the adapter unit from the target temperature storage unit based on the discrimination result of the lens system discrimination unit are provided, and the target temperature control unit controls the temperature adjusting unit according to the target temperature acquired by the target temperature acquisition unit. Thereby, the influence of individual differences in the lens system can be suppressed, and the reference optical path length can be surely made to coincide with the measurement optical path length, so that the three-dimensional shape of the measurement surface can be measured with higher accuracy.

[0022] In a three-dimensional shape measuring apparatus according to another aspect of the present invention, an objective lens that condenses measurement light on the measurement surface is provided, an interference unit is disposed between the objective lens and the measurement surface, and a reference surface is disposed between the objective lens and the interference unit.

[0023] In a three-dimensional shape measurement device according to another aspect of the present invention, a camera that images interference light generated by an interference unit, a scanning unit that relatively scans at least the interference unit with respect to the measurement surface in a scanning direction in which the measurement optical path length changes, and during scanning by the scanning unit, based on the luminance values of pixels at the same coordinates in a plurality of images obtained by repeatedly imaging the interference light by the camera, a shape calculation unit that calculates the height information of the measurement surface for each pixel and obtains the three-dimensional shape of the measurement surface is provided.

[0024] A method for adjusting the reference surface position of a three-dimensional shape measurement device for achieving the object of the present invention includes: splitting a part of measurement light, which is white light, as reference light, emitting the measurement light onto the measurement surface and the reference light onto the reference surface to generate interference light between the measurement light returning from the measurement surface and the reference light returning from the reference surface; an objective lens that condenses the measurement light onto the measurement surface; a holder that houses the interference unit and the reference surface and is formed of a material that reversibly thermally expands in response to temperature changes, and that changes the reference optical path length, which is the optical path length of the reference light between the interference unit and the reference surface, in response to temperature changes. In the method for adjusting the reference surface position of the three-dimensional shape measurement device, there are provided: a temporary target temperature adjustment step of adjusting the temperature of the holder to a predetermined temporary target temperature; a focusing step of focusing the objective lens on the measurement surface; a rough position adjustment step of manually adjusting the position of the reference surface in a state where the holder is adjusted to the temporary target temperature and the objective lens is focused on the measurement surface, so that the reference optical path length substantially matches the measurement optical path length, which is the optical path length of the measurement light between the interference unit and the measurement surface; a temperature change step of changing the temperature of the holder after the rough position adjustment step; an imaging step of repeatedly imaging the interference light while the temperature of the holder is changing; a temperature acquisition step of acquiring the temperature of the holder each time the interference light is imaged in the imaging step; a target temperature determination step of determining, as the target temperature, the temperature at which the intensity of the interference fringes is maximized based on the plurality of images obtained in the imaging step and the temperature of the holder for each image obtained in the temperature acquisition step; and a target temperature adjustment step of adjusting the temperature of the holder to the target temperature determined in the target temperature determination step.

[0025] A method for adjusting the reference surface position of a three-dimensional shape measuring apparatus to achieve the object of the present invention comprises: an interference unit that splits a portion of the measurement light, which is white light, into reference light, emits the measurement light to the surface to be measured and emits the reference light to the reference surface, thereby generating interference light between the measurement light returning from the surface to be measured and the reference light returning from the reference surface; an objective lens that focuses the measurement light onto the surface to be measured; and a holder for housing the interference unit and the reference surface, which is made of a material that reversibly deforms with temperature changes, and which changes the reference optical path length, which is the optical path length of the reference light between the interference unit and the reference surface, with respect to temperature changes. The system includes a focusing step of aligning the objective lens with the surface to be measured; a temperature change step of changing the temperature of the holder after the focusing step; an imaging step of repeatedly imaging interference light while the temperature of the holder is changing; a temperature acquisition step of acquiring the temperature of the holder each time interference light is imaged in the imaging step; a target temperature determination step of determining the temperature at which the intensity of the interference fringes is maximized as the target temperature, based on the multiple images obtained in the imaging step and the temperature of the holder for each image obtained in the temperature acquisition step; and a temperature adjustment step of adjusting the temperature of the holder to the target temperature determined in the target temperature determination step. [Effects of the Invention]

[0026] This invention enables high-precision matching of the measurement optical path length and the reference optical path length at low cost, regardless of the ambient temperature during installation. [Brief explanation of the drawing]

[0027] [Figure 1] This is a schematic diagram of the three-dimensional shape measuring device according to the first embodiment. [Figure 2] This is a functional block diagram of the control unit. [Figure 3] Reference numerals 3A to 3C are explanatory diagrams illustrating the process for determining the target temperature of the reference surface housing. [Figure 4]Reference numeral 4A represents the camera image corresponding to the state shown by reference numeral 3A in Figure 3, reference numeral 4B represents the camera image corresponding to the state shown by reference numeral 3B in Figure 3, and reference numeral 4C represents the camera image corresponding to the state shown by reference numeral 3C in Figure 3. [Figure 5] This is a functional block diagram of the temperature control unit. [Figure 6] This is an explanatory diagram illustrating the calculation of the three-dimensional shape of the surface being measured by the shape calculation unit. [Figure 7] This flowchart shows the process of measuring the three-dimensional shape of a surface to be measured using the three-dimensional shape measuring device of the first embodiment, particularly the method for adjusting the position of the reference surface. [Figure 8] This is a flowchart showing the processing flow of the shape measurement step in Figure 7. [Figure 9] This is a flowchart showing the flow of the measurement process for the three-dimensional shape of a surface to be measured using the three-dimensional shape measuring device of the second embodiment. [Figure 10] This is a functional block diagram of the temperature control unit of the three-dimensional shape measuring device according to the third embodiment. [Figure 11] This is a magnified view of the interference objective lens and thermal insulation material of the white-light interference microscope of the three-dimensional shape measuring device of the fourth embodiment. [Figure 12] This is a magnified view of the interference objective lens of the white-light interference microscope of the three-dimensional shape measuring device according to the fifth embodiment. [Figure 13] This is an explanatory diagram illustrating the challenges of conventional white-light interference microscopes, which constitute a three-dimensional shape measuring device. [Figure 14] This is an explanatory diagram illustrating the challenges of conventional white-light interference microscopes, which constitute a three-dimensional shape measuring device. [Figure 15] This is an explanatory diagram illustrating the challenges of conventional white-light interference microscopes, which constitute a three-dimensional shape measuring device. [Modes for carrying out the invention]

[0028] [First Embodiment] Figure 1 is a schematic diagram of the three-dimensional shape measuring device 9 according to the first embodiment. In the figure, among the mutually orthogonal XYZ directions, the XY direction is parallel to the horizontal direction, and the Z direction is parallel to the vertical direction.

[0029] As shown in Figure 1, the three-dimensional shape measuring device 9 performs three-dimensional shape measurement of the surface to be measured W using the WLI method. This three-dimensional shape measuring device 9 comprises, broadly speaking, a white light interference microscope 10, a drive mechanism 12, a scale 14, a control device 16, and an operating unit 17.

[0030] The white light interference microscope 10 is a Michelson-type scanning white light interference microscope and comprises a light source unit 20, a beam splitter 22, an interference objective lens 24, a temperature control unit 26, a temperature sensor 28, a heat insulating material 30, an imaging lens 32, and a camera 34. The interference objective lens 24, beam splitter 22, imaging lens 32, and camera 34 are arranged in that order along the Z-direction upward from the measurement surface W. The light source unit 20 is positioned opposite the beam splitter 22 in the X-direction (or Y-direction).

[0031] The light source unit 20, under the control of the control device 16, emits a parallel beam of white light (low coherence light with little coherence) as measurement light L1 toward the beam splitter 22. The light source unit 20, although not shown in the figures, includes a light source capable of emitting measurement light L1, such as a light-emitting diode, semiconductor laser, halogen lamp, and high-intensity discharge lamp, and a collector lens that converts the measurement light L1 emitted from this light source into a parallel beam.

[0032] The beam splitter 22 is, for example, a half-mirror. The beam splitter 22 reflects a portion of the measurement light L1 incident from the light source 20 toward the interference objective lens 24 on the lower side in the Z direction. The beam splitter 22 also transmits a portion of the interference light L3, described later, incident from the interference objective lens 24 toward the upper side in the Z direction, and emits this interference light L3 toward the imaging lens 32.

[0033] The interference objective lens 24 is of the Michelson type and comprises an objective lens 24a, a beam splitter 24b, a reference surface 24c, and a holder 24d. The beam splitter 24b and the objective lens 24a are arranged in order along the Z-direction upward from the surface W to be measured, and the reference surface 24c is positioned opposite the beam splitter 24b in the X-direction (or Y-direction).

[0034] The objective lens 24a has a focusing function, and focuses the measurement light L1 incident from the beam splitter 22 onto the surface to be measured W through the beam splitter 24b. For example, a high-magnification objective lens with an NA of 0.7 or higher is used as the objective lens 24a.

[0035] The beam splitter 24b corresponds to the interference section of the present invention, and for example, a half mirror is used. The beam splitter 24b splits a portion of the measurement light L1 incident from the objective lens 24a into reference light L2, transmits the remaining measurement light L1 to the surface to be measured W, and reflects the reference light L2 toward the reference surface 24c. In the figure, the symbol D1 indicates the measurement optical path length, which is the optical path length of the measurement light L1 between the beam splitter 24b and the surface to be measured W. The measurement light L1 that has passed through the beam splitter 24b is irradiated onto the surface to be measured W, and then reflected by the surface to be measured W and returns to the beam splitter 24b.

[0036] The reference plane 24c, for example, uses a reflective mirror to reflect the reference light L2 incident from the beam splitter 24b back towards the beam splitter 24b. The position of this reference plane 24c in the X direction can be manually adjusted by the reference plane position adjustment mechanism 25.

[0037] The reference plane position adjustment mechanism 25 is, for example, a screw-type fine adjustment mechanism that adjusts the X-direction position of the reference plane 24c in response to input from the operator. This makes it possible to adjust the reference optical path length D2, which is the optical path length of the reference light L2 between the beam splitter 24b and the reference plane 24c. The reference plane position adjustment mechanism 25 is used for manual adjustment (approximate adjustment) to adjust the X-direction position of the reference plane 24c so that the reference optical path length D2 approximately matches the measured optical path length D1.

[0038] The beam splitter 24b generates interference light L3 from the measurement light L1 returning from the surface to be measured W and the reference light L2 returning from the reference surface 24c, and emits this interference light L3 toward the objective lens 24a on the upper side in the Z direction. This interference light L3 passes through the objective lens 24a and the beam splitter 22 and enters the imaging lens 32. The interference light L3 is light that contains interference fringes 101 (see Figure 4).

[0039] The holder 24d is made of a metal material such as brass, that is, a material that is reversibly thermally deformable. This holder 24d comprises a lens barrel 24d1 and a reference surface housing section 24d2. The lens barrel 24d1 is formed in a cylindrical shape extending in the Z direction and houses (holds) the objective lens 24a and the beam splitter 24b. The reference surface housing section 24d2 is formed in a cylindrical shape extending in the X direction from the holding position of the beam splitter 24b in the lens barrel 24d1 and houses the reference surface 24c. As previously described, the position of the reference surface 24c in the X direction can be manually adjusted by the reference surface position adjustment mechanism 25.

[0040] The temperature adjustment unit 26 is located near the reference plane housing 24d2 and, under the control of the control device 16 described later, adjusts the temperature at least between the beam splitter 24b and the reference plane 24c, i.e., the temperature of the reference plane housing 24d2. For example, a heater and a Peltier element can be used as this temperature adjustment unit 26.

[0041] As previously described, the reference surface housing 24d2 is made of brass and therefore undergoes reversible thermal deformation (expansion and contraction) in response to temperature changes. For this reason, by changing the temperature of the reference surface housing 24d2 using the temperature adjustment unit 26, the reference surface housing 24d2 is thermally deformed, and the X-direction position of the reference surface 24c can be adjusted accordingly. Furthermore, by precisely controlling the temperature of the reference surface housing 24d2, the X-direction position of the reference surface 24c can be adjusted with higher precision (higher resolution) than with the reference surface position adjustment mechanism 25, i.e., the reference optical path length D2 can be adjusted with higher precision. In this embodiment, under the control of the control device 16, the temperature of the reference surface housing 24d2 is adjusted by the temperature adjustment unit 26 to precisely adjust the X-direction position of the reference surface 24c (reference optical path length D2) so that the reference optical path length D2 matches the measured optical path length D1.

[0042] The temperature sensor 28 corresponds to the temperature measuring unit of the present invention. The temperature sensor 28 is located near the reference surface housing 24d2 and measures the temperature of at least the reference surface housing 24d2 (between the beam splitter 24b and the reference surface 24c) within the holder 24d, and outputs the temperature measurement result to the control device 16. The measurement result of this temperature sensor 28 is used by the control device 16 to control the temperature adjustment unit 26, that is, to adjust the X-direction position of the reference surface 24c (adjustment of the reference optical path length D2).

[0043] The thermal insulation material 30 is provided to cover the entire interference objective lens 24, the temperature adjustment unit 26, and the temperature sensor 28. This prevents the temperature inside the thermal insulation material 30, particularly the temperature of the reference surface housing unit 24d2 and its vicinity, from changing due to external influences.

[0044] The imaging lens 32 images the interference light L3 incident from the beam splitter 22 onto the imaging plane of the camera 34 (not shown in the figure). Specifically, the imaging lens 32 images a point on the focal plane of the objective lens 24a as an image point on the imaging plane of the camera 34.

[0045] Camera 34, although not shown in the figure, is equipped with a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) type image sensor. Camera 34 captures the interference light L3 that is imaged onto the imaging surface of the image sensor using an imaging lens 32, and processes the image signal of the interference light L3 obtained by this capture to output an image 36. This image 36 is an image that includes interference fringes 101 (see Figure 4).

[0046] The drive mechanism 12 corresponds to the scanning unit of the present invention. The drive mechanism 12 is composed of various actuators, such as a known linear motor or motor drive mechanism, and holds the white light interference microscope 10 so that it can move in the scanning direction, which is the Z direction. Under the control of the control device 16, the drive mechanism 12 scans the white light interference microscope 10 along the Z direction. This makes it possible to change the measurement optical path length D1 when measuring the three-dimensional shape of the surface to be measured W.

[0047] The drive mechanism 12 only needs to be capable of scanning the white light interference microscope 10 or at least its beam splitter 24b relative to the surface to be measured W in the Z direction. For example, it may scan the surface to be measured W (the support part that supports the surface to be measured W) in the Z direction.

[0048] Scale 14 is a position detection sensor that detects the Z-direction position of the white light interference microscope 10, and a linear scale is used, for example. This scale 14 repeatedly detects the Z-direction position of the white light interference microscope 10 and repeatedly outputs the position detection result to the control device 16.

[0049] The control device 16 comprehensively controls the adjustment of the X-direction position of the reference surface 24c, the measurement operation of the three-dimensional shape of the surface W to be measured by the white light interference microscope 10, and the calculation of the three-dimensional shape of the surface W to be measured, in response to input operations to the operation unit 17. This control device 16 is equipped with an arithmetic circuit composed of various processors and memory. Various processors include CPUs (Central Processing Units), GPUs (Graphics Processing Units), ASICs (Application Specific Integrated Circuits), and programmable logic devices [e.g., SPLDs (Simple Programmable Logic Devices), CPLDs (Complex Programmable Logic Devices), and FPGAs (Field Programmable Gate Arrays)]. The various functions of the control device 16 may be implemented by a single processor, or by multiple processors of the same or different types.

[0050] Figure 2 is a functional block diagram of the control device 16. As shown in Figure 2, the control device 16 is connected to various parts of the white light interference microscope 10 (light source unit 20, temperature adjustment unit 26, temperature sensor 28, and camera 34), the drive mechanism 12, the scale 14, and the operation unit 17.

[0051] The control device 16 functions as a focus control unit 98, a temperature control unit 100, a measurement control unit 102, and a shape calculation unit 104 by executing a control program (not shown) read from a storage unit (not shown).

[0052] The focusing control unit 98 performs focusing control to adjust the focus of the objective lens 24a to the surface to be measured W when adjusting the position of the reference surface 24c in the X direction (when determining the target temperature, as described later) and when measuring the three-dimensional shape of the surface to be measured W.

[0053] For example, the focusing control unit 98 emits measurement light L1 from the light source unit 20 and scans the white light interference microscope 10 in the Z direction using the drive mechanism 12. Furthermore, while this scanning is being performed, the camera 34 repeatedly captures interference light L3 and outputs the captured images 36. Next, the focusing control unit 98 calculates the degree of focus (contrast value) for each pixel of each captured image 36 based on the multiple captured images 36 output from the camera 34, and determines the Z-direction position of the white light interference microscope 10 so that the focus of the objective lens 24a aligns with the surface to be measured W based on this calculation result. Then, based on the determination result of the Z-direction position of the white light interference microscope 10, the focusing control unit 98 controls the drive mechanism 12 to adjust the Z-direction position of the white light interference microscope 10 so that the focus of the objective lens 24a aligns with the surface to be measured W.

[0054] The method of focusing control by the focusing control unit 98 is not limited to the method described above, and various known methods may be used. In this embodiment, a test pattern 99 for focusing control is formed on the surface W to be measured, which is used for adjusting the X-direction position of the reference surface 24c (see Figure 4).

[0055] The temperature control unit 100 controls the temperature adjustment unit 26 to adjust the temperature of the reference plane housing unit 24d2. This allows the temperature control unit 100 to adjust the X-direction position of the reference plane 24c, i.e., the reference optical path length D2. As previously described, the reference plane housing unit 24d2 (holder 24d) is made of a material that is reversibly thermally deformable. Therefore, the reference optical path length D2 changes as the reference plane housing unit 24d2 deforms thermally depending on the ambient temperature in which the white light interference microscope 10 is installed. Conversely, the reference optical path length D2 can be adjusted to a desired value by adjusting the temperature of the reference plane housing unit 24d2.

[0056] Therefore, in this embodiment, with the objective lens 24a focused on the surface to be measured W, the target temperature of the reference surface housing 24d2 (holder 24d) is determined in advance so that the reference optical path length D2 matches the measurement optical path length D1, and the reference surface housing 24d2 is adjusted to the target temperature. This adjusts the X-direction position of the reference surface 24c so that the reference optical path length D2 matches the measurement optical path length D1.

[0057] The symbols 3A to 3C in Figure 3 are explanatory diagrams illustrating the flow of the process for determining the target temperature of the reference plane storage unit 24d2. In Figure 4, symbol 4A is an image 36 captured by camera 34 corresponding to the state of symbol 3A in Figure 3, symbol 4B is an image 36 captured by camera 34 corresponding to the state of symbol 3B in Figure 3, and symbol 4C is an image 36 captured by camera 34 corresponding to the state of symbol 3C in Figure 3. The vertical axis in Figure 4 indicates the Z-direction position of the white interference microscope 10 when imaging is performed by camera 34.

[0058] The white light interference microscope 10 has a surface to be measured W on which a test pattern 99 is formed, pre-set. As shown by reference numeral 3A in Figure 3 and reference numeral 4A in Figure 4, the temperature control unit 100 controls the temperature adjustment unit 26 to adjust the temperature of the reference surface storage unit 24d2 to a predetermined provisional target temperature. In this case, the temperature control unit 100 functions as a provisional target temperature control unit of the present invention. The provisional target temperature is, for example, the recommended ambient temperature for use of the interference objective lens 24 as determined by the manufacturer. In this state, the image of the test pattern 99 in the captured image 36 captured by the camera 34 is out of focus.

[0059] Next, as shown by reference numeral 3B in Figure 3 and reference numeral 4B in Figure 4, the aforementioned focusing control unit 98 performs focusing control (adjustment of the Z-direction position of the white light interference microscope 10) to align the focus of the objective lens 24a with the test pattern 99 on the surface to be measured W. As a result, the image of the test pattern 99 in the captured image 36 captured by the camera 34 is in focus, but the measurement optical path length D1 changes, causing a mismatch between the measurement optical path length D1 and the reference optical path length D2, thus suppressing the generation of interference fringes 101 in the captured image 36.

[0060] As shown by reference numeral 3C in Figure 3 and reference numeral 4C in Figure 4, after the focusing control unit 98 completes the focusing control, the operator manually adjusts (approximately adjusts) the X-direction position of the reference plane 24c using the reference plane position adjustment mechanism 25 to approximate match the reference optical path length D2 with the measured optical path length D1. For example, the operator operates the reference plane position adjustment mechanism 25 while observing the captured image 36 captured by the camera 34 to adjust the X-direction position of the reference plane 24c to the position where the intensity of the interference fringes 101 in the captured image 36 is strongest.

[0061] As previously described, in order to precisely match the reference optical path length D2 to the measured optical path length D1 using only the reference plane position adjustment mechanism 25, a reference plane position adjustment mechanism 25 having a control resolution sufficiently smaller than the depth of focus of the objective lens 24a (e.g., DOF = 0.56 μm) is required. On the other hand, if it is only necessary to roughly match the reference optical path length D2 to the measured optical path length D1, as in this embodiment, this can be done with a screw-type reference plane position adjustment mechanism 25.

[0062] After manual adjustment by the reference plane position adjustment mechanism 25 is completed, the temperature control unit 100 controls the temperature adjustment unit 26 to change the temperature of the reference plane housing 24d2 from the provisional target temperature, while repeatedly performing the acquisition of interference light L3 by the camera 34 and output of the acquired image 36, and the measurement of the temperature of the reference plane housing 24d2 by the temperature sensor 28. The range of temperature change of the reference plane housing 24d2 is set to, for example, a certain range centered on the provisional target temperature.

[0063] Next, the temperature control unit 100 searches for and determines a target temperature in which the reference optical path length D2 matches the measured optical path length D1, based on the multiple captured images 36 obtained during the temperature change of the reference surface housing unit 24d2 and the temperature of the reference surface housing unit 24d2, as will be described in more detail later. Then, the temperature control unit 100 controls the temperature adjustment unit 26 to adjust the temperature of the reference surface housing unit 24d2 to the target temperature. In this case, the temperature control unit 100 functions as a target temperature control unit of the present invention.

[0064] Figure 5 is a functional block diagram of the temperature control unit 100. As shown in Figure 5, the temperature control unit 100 controls the adjustment of the reference surface housing unit 24d2 to a provisional target temperature, the temperature change of the reference surface housing unit 24d2, the determination of the target temperature, and the adjustment of the reference surface housing unit 24d2 to the target temperature.

[0065] Furthermore, the temperature control method for the reference surface housing 24d2 by the temperature control unit 100 is, for example, feedback control that adjusts the temperature of the reference surface housing 24d2 based on the measurement results of the temperature sensor 28. PID (Proportional-Integral-Differential) control is an example of this feedback control.

[0066] The temperature control unit 100 includes a temperature acquisition unit 100a, a target temperature storage unit 100b, a calculation processing unit 100c, an output control unit 100d, a temperature change control unit 100e, an image acquisition unit 100f, and a target temperature determination unit 100g.

[0067] The temperature acquisition unit 100a is, for example, an interface connected to the temperature sensor 28. The temperature acquisition unit 100a repeatedly acquires the temperature measurement result from the temperature sensor 28 and outputs the temperature measurement result to the calculation processing unit 100c or the target temperature determination unit 100g each time the temperature measurement result of the reference surface storage unit 24d2 is repeatedly output from the temperature sensor 28. When the temperature adjustment is performed to adjust the reference surface storage unit 24d2 to a provisional target temperature or the target temperature, the temperature acquisition unit 100a outputs the temperature measurement result to the calculation processing unit 100c. In addition, when the temperature of the reference surface storage unit 24d2 changes, the temperature acquisition unit 100a outputs the temperature measurement result to the target temperature determination unit 100g in conjunction with the imaging of the interference light L3 by the camera 34.

[0068] The target temperature storage unit 100b stores a predetermined provisional target temperature according to the type of interference objective lens 24, and the target temperature determined by the target temperature determination unit 100g, which will be described later. The target temperature storage unit 100b may be located on a server on the internet.

[0069] The calculation processing unit 100c obtains a provisional target temperature from the target temperature storage unit 100b before determining the target temperature, and obtains the target temperature from the target temperature storage unit 100b after determining the target temperature. Then, each time a new temperature measurement result is input from the temperature sensor 28, the calculation processing unit 100c calculates the difference between this temperature measurement result and the provisional target temperature or target temperature (hereinafter abbreviated as target temperature, etc.), and outputs this difference calculation result to the output control unit 100d.

[0070] The output control unit 100d controls the temperature of the temperature adjustment unit 26. The output control unit 100d stores, for example, a data table or calculation formula that defines the relationship between the difference calculation result from the calculation processing unit 100c and the amount of temperature adjustment required by the temperature adjustment unit 26 to adjust the temperature of the reference surface housing unit 24d2 to a target temperature. Based on the difference calculation result input from the calculation processing unit 100c, the output control unit 100d controls the temperature adjustment unit 26 by referring to the aforementioned data table or formula to adjust the temperature of the reference surface housing unit 24d2 to a target temperature.

[0071] When an operator performs a temperature change start operation on the operation unit 17 after manually adjusting the reference surface position adjustment mechanism 25, the temperature change control unit 100e controls the temperature adjustment unit 26 via the output control unit 100d to change the temperature of the reference surface storage unit 24d2 within a certain range centered on, for example, a provisional target temperature.

[0072] The image acquisition unit 100f is, for example, an interface connected to the camera 34. While the temperature of the reference surface storage unit 24d2 is being changed, the image acquisition unit 100f repeatedly causes the camera 34 to capture interference light L3, and repeatedly acquires the captured image 36 from the camera 34 and outputs the captured image 36 to the target temperature determination unit 100g.

[0073] The target temperature determination unit 100g determines the target temperature of the reference surface storage unit 24d2. The camera 34 and the temperature acquisition unit 100a are connected to this target temperature determination unit 100g. While the temperature adjustment unit 26 is changing the temperature of the reference surface storage unit 24d2, the target temperature determination unit 100g repeatedly acquires captured images 36 from the image acquisition unit 100f and repeatedly acquires temperature measurement results from the temperature acquisition unit 100a to search for and determine the target temperature.

[0074] Specifically, the target temperature determination unit 100g detects interference fringes 101 within each of the multiple captured images 36 input from the image acquisition unit 100f, and further detects their intensity (pixel value). Next, the target temperature determination unit 100g selects the captured image 36 from among the multiple captured images 36 input from the image acquisition unit 100f that has the maximum intensity of interference fringes 101, that is, the captured image 36 that was captured while the measurement optical path length D1 and the reference optical path length D2 were matching.

[0075] The target temperature determination unit 100g then determines the temperature measurement result corresponding to the selected image 36 as the target temperature and stores this target temperature in the target temperature storage unit 100b. As a result, with the objective lens 24a focused on the surface to be measured W, the temperature control unit 100 adjusts the temperature of the reference surface storage unit 24d2 to the target temperature, thereby automatically adjusting the X-direction position of the reference surface 24c so that the reference optical path length D2 matches the measured optical path length D1.

[0076] Returning to Figure 2, the measurement control unit 102 controls the drive mechanism 12, the light source unit 20, and the camera 34 to perform three-dimensional shape measurement of the surface to be measured W using the WLI method.

[0077] Specifically, the measurement control unit 102 starts emitting measurement light L1 from the light source unit 20, and then controls the drive mechanism 12 to scan the white light interference microscope 10 in the Z direction. While the drive mechanism 12 is scanning the white light interference microscope 10 in the Z direction, the measurement control unit 102, based on the detection result of the Z-direction position of the white light interference microscope 10 by the scale 14, repeatedly causes the camera 34 to capture interference light L3 and outputs the captured image 36 to the control device 16 each time the white light interference microscope 10 moves by a certain pitch in the Z direction. The captured image 36 for each pitch is then input from the camera 34 to the shape calculation unit 104.

[0078] Furthermore, since the Z-direction position of camera 34 when imaging interference light L3 with camera 34 can be detected by scale 14, the pitch when scanning the white light interference microscope 10 in the Z-direction is not limited to a constant pitch but may be an unequal pitch (the same applies hereafter).

[0079] Figure 6 is an explanatory diagram illustrating the calculation of the three-dimensional shape of the surface to be measured W by the shape calculation unit 104. The shape calculation unit 104 calculates the three-dimensional shape of the surface to be measured W. Each time the white light interference microscope 10 moves by a certain pitch, the shape calculation unit 104 acquires the captured image 36 input from the camera 34 via an interface such as the image acquisition unit 100f described above.

[0080] Next, as shown in Figure 6, the shape calculation unit 104 detects the brightness value of each pixel in each captured image 36 where interference fringes 101 are generated. The shape calculation unit 104 then compares the brightness values ​​(see symbol P1) of each pixel at the same coordinate in each captured image 36 (image sensor of the camera 34). Here, Figure 6 shows the relationship between the brightness value and the Z-direction position of any single pixel. The shape calculation unit 104 calculates the height information of the surface W to be measured for each pixel at the same coordinate by determining the Z-direction position where the brightness value is maximized for each pixel at the same coordinate. This allows the three-dimensional shape of the surface W to be measured to be determined. Note that the calculation of the three-dimensional shape of the surface W to be measured using the WLI method is a known technique (see Patent Document 1 above), so a detailed explanation is omitted here.

[0081] [Operation of the First Embodiment] Figure 7 is a flowchart showing the flow of the measurement process of the three-dimensional shape of the surface to be measured W by the three-dimensional shape measuring device 9 of the first embodiment, particularly the method for adjusting the reference surface position. As shown in Figure 7, the measurement process of the three-dimensional shape of the surface to be measured W by the three-dimensional shape measuring device 9 is broadly divided into a target temperature determination step S10 and a shape measurement step S20.

[0082] In the target temperature determination step S10, the target temperature of the reference plane storage section 24d2 (holder 24d) is determined. The target temperature determination step S10 is performed, for example, each time a new interference objective lens 24 is attached to the white light interference microscope 10, or at regular intervals.

[0083] First, the operator sets the surface to be measured W on which the test pattern 99 is formed in the white light interference microscope 10. Alternatively, various patterns formed on the surface W of a three-dimensional object to be measured may be used as the test pattern 99.

[0084] After setting the surface to be measured W (test pattern 99) on the white interference microscope 10, the operator operates the control unit 17 to initiate the target temperature determination operation. The temperature acquisition unit 100a then repeatedly acquires the temperature measurement result from the temperature sensor 28 to the reference surface storage unit 24d2 and outputs the temperature measurement result to the calculation processing unit 100c.

[0085] At the same time, the calculation processing unit 100c acquires information on the provisional target temperature from the target temperature storage unit 100b. Next, each time a new temperature measurement result is input from the temperature acquisition unit 100a, the calculation processing unit 100c calculates the difference between this temperature measurement result and the provisional target temperature, and outputs this difference calculation result to the output control unit 100d. Then, the output control unit 100d controls the temperature adjustment unit 26 based on the difference calculation result to adjust the reference surface storage unit 24d2 to the provisional target temperature (step S11, corresponding to the provisional target temperature adjustment step of the present invention).

[0086] In this embodiment, the interference objective lens 24, the temperature adjustment unit 26, and the temperature sensor 28 are covered with the heat insulating material 30, so that the temperature inside the heat insulating material 30, especially the reference surface housing unit 24d2 and its vicinity, can be stabilized at a provisional target temperature.

[0087] If the reference surface housing 24d2 is adjusted to a provisional target temperature based on the temperature measurement result of the temperature sensor 28, the focus control unit 98 controls the light source unit 20, the drive mechanism 12, and the camera 34 to perform focus control to adjust the focus of the objective lens 24a to the test pattern 99 (step S12, corresponding to the focus step of the present invention). Step S12 may be performed before step S11 or simultaneously with step S11.

[0088] Once focusing control is complete, the operator manually adjusts the X-direction position of the reference plane 24c using the reference plane position adjustment mechanism 25 to roughly match the reference optical path length D2 with the measured optical path length D1 (step S13, corresponding to the approximate position adjustment step of the present invention). As described above, since it is sufficient to roughly match the reference optical path length D2 with the measured optical path length D1, this can be done with a screw-type reference plane position adjustment mechanism 25, which reduces the cost of the white light interference microscope 10. Then, the operator initiates the temperature change operation of the reference plane storage section 24d2 using the operation unit 17.

[0089] When the operation to start the temperature change is performed in the operation unit 17, the temperature change control unit 100e controls the temperature adjustment unit 26 via the output control unit 100d to start the temperature change of the reference surface storage unit 24d2 (step S14, corresponding to the temperature change step of the present invention).

[0090] When the temperature of the reference surface storage unit 24d2 begins to change, the image acquisition unit 100f repeatedly causes the camera 34 to capture the interference light L3, and repeatedly acquires the captured image 36 from the camera 34 and outputs the captured image 36 to the target temperature determination unit 100g (step S15, corresponding to the imaging step of the present invention). At the same time, the temperature acquisition unit 100a repeatedly acquires the temperature measurement results from the temperature sensor 28 in conjunction with the imaging of the interference light L3 by the camera 34 and repeatedly outputs them to the target temperature determination unit 100g (step S15, corresponding to the temperature acquisition step of the present invention).

[0091] Subsequently, while the temperature change of the reference surface storage unit 24d2 continues, the output of the captured image 36 from the image acquisition unit 100f to the target temperature determination unit 100g and the output of the temperature measurement result from the temperature acquisition unit 100a to the target temperature determination unit 100g are repeatedly performed (NO in step S16).

[0092] After the temperature change of the reference surface storage unit 24d2 is complete (YES in step S16), the target temperature determination unit 100g selects the image 36 from among the image acquisition units 36 input from the image acquisition unit 100f that has the maximum intensity of interference fringes 101, and determines the temperature measurement result corresponding to this image 36 as the target temperature (step S17, corresponding to the target temperature determination step of the present invention). Then, the target temperature determination unit 100g stores the determined target temperature in the target temperature storage unit 100b. This completes all processing of the target temperature determination step S10.

[0093] Figure 8 is a flowchart showing the processing flow of the shape measurement step S20 in Figure 7. As shown in Figure 8, after the target temperature determination step S10 is completed, the operator sets the surface to be measured W in the white light interference microscope 10 and operates the control unit 17 to start the measurement of the three-dimensional shape of the surface to be measured W.

[0094] When the measurement start operation is performed, the focus control unit 98 performs the same focus control as in step S13 described above to adjust the focus of the objective lens 24a to the surface to be measured W (step S21). Note that the focus control in step S21 may be omitted.

[0095] Once the focusing control is complete, the temperature acquisition unit 100a repeatedly acquires the temperature measurement result of the reference surface housing unit 24d2 from the temperature sensor 28 and outputs the temperature measurement result to the calculation processing unit 100c.

[0096] At the same time, the calculation processing unit 100c acquires target temperature information from the target temperature storage unit 100b, and each time a new temperature measurement result from the temperature acquisition unit 100a is input from the temperature sensor 28, it outputs the difference calculation result between this temperature measurement result and the target temperature to the output control unit 100d. The output control unit 100d then controls the temperature adjustment unit 26 based on the difference calculation result to adjust the reference plane housing unit 24d2 to the target temperature (step S22, corresponding to the target temperature adjustment step of the present invention). Since the interference objective lens 24, the temperature adjustment unit 26, and the temperature sensor 28 are covered with heat insulating material 30, the reference plane housing unit 24d2 and its vicinity stabilize at the target temperature.

[0097] When the reference surface housing 24d2 is adjusted to the target temperature determined in the target temperature determination step S10, the reference surface housing 24d2 is thermally deformed, and the X-direction position of the reference surface 24c can be automatically adjusted to a position where the reference optical path length D2 matches the measured optical path length D1.

[0098] Here, for example, the linear thermal expansion coefficient of brass is 20 × 10 -6 Assuming a temperature of (1 / °C) and a reference optical path length D2 of 5 mm, the change in the X-direction position of the reference surface 24c for a temperature change of 1°C in the reference surface housing 24d2 is 0.1 μm [= (20 × 10 -6 ) × (5 × 10 -3 )×1]. Generally, temperature control in units of 1°C is easy, so when adjusting the X-direction position of the reference surface 24c by adjusting the temperature of the reference surface housing 24d2, sufficient control resolution can be obtained for the depth of focus (DOF = 0.56 μm) of the objective lens 24a. As a result, when the focus of the objective lens 24a is aligned with the surface to be measured W, the reference optical path length D2 can be matched with the measurement optical path length D1 with high precision. Consequently, the intensity of the interference fringes 101 contained in the interference light L3 generated by the beam splitter 24b becomes stronger.

[0099] Furthermore, in this embodiment, regardless of the ambient temperature at which the white light interference microscope 10 is installed, the temperature adjustment unit 26 can adjust and maintain the temperature of the reference plane storage unit 24d2 to the target temperature, making it possible to maintain a state in which the reference optical path length D2 matches the measured optical path length D1.

[0100] The timing of step S22 is not limited to this. For example, step S22 may be started when the system (three-dimensional shape measuring device 9) is powered on, and the temperature of the holder (reference surface storage unit 24d2) may be continuously adjusted until the measurement of all objects to be measured (surfaces to be measured W) is completed.

[0101] Then, based on the temperature measurement result of the temperature sensor 28, when the reference surface storage unit 24d2 is adjusted to the target temperature, the measurement control unit 102 controls the drive mechanism 12 to start scanning the white light interference microscope 10 in the Z direction (step S23). Also, based on the detection result of the Z-direction position of the white light interference microscope 10 by the scale 14, the measurement control unit 102 repeatedly performs imaging of interference light L3 with the camera 34 each time the white light interference microscope 10 moves by a certain pitch in the Z direction (steps S24, NO in step S25, step S26). As a result, the captured image 36 in which interference fringes 101 are generated is sequentially input from the camera 34 to the shape calculation unit 104.

[0102] When scanning by the white light interference microscope 10 is completed (YES in step S25), the shape calculation unit 104 detects the brightness value for each pixel in each captured image 36 where interference fringes 101 are generated, and determines the Z-direction position where the brightness value is maximized for each pixel at the same coordinate in each captured image 36, thereby calculating the height information of the surface to be measured W for each pixel at the same coordinate. As a result, the shape calculation unit 104 calculates the three-dimensional shape of the surface to be measured W (step S27).

[0103] Subsequently, each time the surface W to be measured changes, the process from step S21 (step S21 is optional) to step S27 described above is repeatedly executed. Note that when switching the interference objective lens 24 attached to the white interference microscope 10, the process from the target temperature determination step S10 described above is repeatedly executed.

[0104] As described above, in the first embodiment, with the objective lens 24a focused on the surface to be measured W, the target temperature of the reference surface housing 24d2 is determined in advance so that the reference optical path length D2 matches the measured optical path length D1. By adjusting the temperature of the reference surface housing 24d2 to this target temperature, the reference optical path length D2 can be automatically and accurately matched to the measured optical path length D1. Furthermore, a costly, high-resolution reference surface position adjustment mechanism 25 becomes unnecessary. Regardless of the ambient temperature at which the white light interference microscope 10 is installed, the state in which the reference optical path length D2 matches the measured optical path length D1 can be maintained at low cost.

[0105] [Second Embodiment] Next, a description of the three-dimensional shape measuring device 9 according to the second embodiment of the present invention will be given. In the three-dimensional shape measuring device 9 of the first embodiment described above, when determining the target temperature of the reference surface housing section 24d2, the operator manually adjusts the reference surface position adjustment mechanism 25 to roughly match the reference optical path length D2 with the measurement optical path length D1. In contrast, the three-dimensional shape measuring device 9 of the second embodiment automatically determines the target temperature of the reference surface housing section 24d2 without manual adjustment of the reference surface position adjustment mechanism 25.

[0106] Figure 9 is a flowchart showing the flow of the measurement process for the three-dimensional shape of the surface to be measured W by the three-dimensional shape measuring device 9 of the second embodiment. The three-dimensional shape measuring device 9 of the second embodiment has basically the same configuration as the three-dimensional shape measuring device 9 of the first embodiment, except that it performs the target temperature determination step S10A instead of the target temperature determination step S10 of the first embodiment. Therefore, components that are functionally or structurally identical to those of the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0107] As shown in Figure 9, in the target temperature determination step S10A of the second embodiment, after the measurement surface W is set on the white interference microscope 10, the operator operates the control unit 17 to start the target temperature determination operation, and the focus control unit 98 performs focus control to adjust the focus of the objective lens 24a to the test pattern 99 (step S12).

[0108] In the second embodiment, once the focusing control is complete, the temperature change control unit 100e controls the temperature adjustment unit 26 via the output control unit 100d to start the temperature change of the reference surface housing unit 24d2 (step S14). In the second embodiment, since the reference optical path length D2 is not roughly matched to the measurement optical path length D1 in advance as in the first embodiment, it is preferable to set the range of temperature change of the reference surface housing unit 24d2 to be wider than in the first embodiment.

[0109] Hereafter, as in the first embodiment (see Figure 7), while the temperature change of the reference surface storage unit 24d2 continues, the output of the captured image 36 from the image acquisition unit 100f to the target temperature determination unit 100g and the output of the temperature measurement result from the temperature acquisition unit 100a to the target temperature determination unit 100g are repeatedly performed (NO in steps S15 and S16).

[0110] Next, the target temperature determination unit 100g determines the target temperature and stores it in the target temperature storage unit 100b, similar to the first embodiment, based on the multiple captured images 36 input from the image acquisition unit 100f and the multiple temperature measurement results input from the temperature acquisition unit 100a during the temperature change of the reference surface storage unit 24d2 (YES in step S16, step S17). This completes all processing of the target temperature determination step S10A of the second embodiment. Note that the shape measurement step S20 is the same as in the first embodiment (see Figure 8), so a detailed explanation is omitted.

[0111] As described above, in the second embodiment, the target temperature of the reference surface storage section 24d2 can be determined entirely automatically without manual adjustment by the reference surface position adjustment mechanism 25. Therefore, in addition to the effects described in the first embodiment, the three-dimensional shape measurement of the surface to be measured W is made more efficient (automated) than in the first embodiment.

[0112] [Third Embodiment] Figure 10 is a functional block diagram of the temperature control unit 100 of the three-dimensional shape measuring device 9 of the third embodiment. The white light interference microscope 10 of the three-dimensional shape measuring device 9 of the third embodiment is provided with an adapter unit 23. Multiple lens systems 110, each consisting of an interference objective lens 24, a temperature adjustment unit 26, and a temperature sensor 28, are selectively mounted on this adapter unit 23.

[0113] Here, temperature variations occur in the lens system 110 due to the position of the temperature adjustment unit 26, the position of the temperature sensor 28, and the condition of the heat insulating material 30. These temperature variations differ from one lens system 110 to another, and even if lens systems 110 are equipped with the same type of interference objective lens 24, the target temperature is not necessarily the same. For this reason, it is necessary to manage the target temperature for each lens system 110. Therefore, the three-dimensional shape measuring device 9 of the third embodiment manages the target temperature for each of the multiple lens systems 110 and adjusts the temperature of the reference surface storage unit 24d2 according to the target temperature corresponding to the lens system 110 mounted on the adapter unit 23.

[0114] As shown in Figure 10, the three-dimensional shape measuring device 9 of the third embodiment has basically the same configuration as the three-dimensional shape measuring device 9 of each of the above embodiments, except that the database 112 is stored in the target temperature storage unit 100b of the temperature control unit 100, and the temperature control unit 100 functions as a lens system discrimination unit 100h and a target temperature acquisition unit 100i. For this reason, components that are functionally or structurally identical to those of each of the above embodiments are given the same reference numerals and their descriptions are omitted. Note that in Figure 10, some functions of the temperature control unit 100 (temperature change control unit 100e, image acquisition unit 100f, and target temperature determination unit 100g) are omitted from the illustration in order to avoid making the drawing more complex.

[0115] Database 112 stores information showing the correspondence between the lens ID (identification), which is the unique identification information (individual identification number) for each lens system 110, and the target temperature determined for each lens system 110 in the aforementioned target temperature determination steps S10 and S10A. Note that database 112 may be located on an external server rather than within the target temperature storage unit 100b.

[0116] The lens system discrimination unit 100h discriminates the lens ID of the lens system 110 attached to the adapter unit 23 and outputs the discrimination result to the target temperature acquisition unit 100i. For example, the lens system 110 may be provided with an ID storage unit (not shown) that stores the lens ID, and the lens system discrimination unit 100h may perform lens ID discrimination by obtaining the lens ID from the ID storage unit. Alternatively, the lens system discrimination unit 100h may perform lens ID discrimination based on the lens ID input by the operator operating the operation unit 17.

[0117] The target temperature acquisition unit 100i acquires the target temperature corresponding to the lens ID input from the lens system discrimination unit 100h from the database 112 and outputs it to the calculation processing unit 100c. The calculation processing unit 100c then calculates the difference between the temperature measurement results of the temperature sensor 28, which are repeatedly input from the temperature acquisition unit 100a, and the target temperature input from the target temperature acquisition unit 100i. Then, similar to the embodiments described above, the output control unit 100d controls the temperature adjustment unit 26 based on the difference calculation result to adjust the reference surface housing unit 24d2 of the lens system 110 to the target temperature (provisional target temperature).

[0118] As described above, in the third embodiment, since the target temperature corresponding to the lens system 110 mounted on the adapter unit 23 can be obtained from the database 112, the reference surface storage unit 24d2 can be adjusted to the target temperature specified for each lens system 110. As a result, the influence of individual differences in the lens system 110 can be suppressed, and the reference optical path length D2 can be reliably matched to the measurement optical path length D1 when the focus of the objective lens 24a is aligned with the surface W to be measured. This enables more accurate measurement of the three-dimensional shape of the surface W to be measured.

[0119] [Fourth Embodiment] Figure 11 is an enlarged view of the interference objective lens 24 and thermal insulation material 30A of the white light interference microscope 10 of the three-dimensional shape measuring device 9 of the fourth embodiment.

[0120] In each of the above embodiments, the entire interference objective lens 24, the temperature adjustment unit 26, and the temperature sensor 28 are covered by the heat insulating material 30. However, as shown in Figure 11, in the fourth embodiment, only the reference plane housing unit 24d2, the temperature adjustment unit 26, and the temperature sensor 28 are covered by the heat insulating material 30A. The fourth embodiment has basically the same configuration as the above embodiments, except that it is equipped with a different heat insulating material 30A than the heat insulating material 30 of the above embodiments. Therefore, components that are functionally or structurally identical to those in the above embodiments are denoted by the same reference numerals and their descriptions are omitted.

[0121] In this way, by covering the reference surface housing 24d2, temperature adjustment unit 26, and temperature sensor 28 with the heat insulating material 30A, the reference surface housing 24d2 and its vicinity can be stabilized at the target temperature (provisional target temperature), similar to the embodiments described above. Furthermore, since the occurrence of aberrations in the objective lens 24a due to the heat generated in the temperature adjustment unit 26 can be minimized, three-dimensional shape measurement of the surface to be measured W that is resistant to temperature changes can be performed. As a result, even higher accuracy and reliability of three-dimensional shape measurement of the surface to be measured W becomes possible.

[0122] [Fifth Embodiment] Figure 12 is an enlarged view of the interference objective lens 200 of the white light interference microscope 10 of the three-dimensional shape measuring device 9 of the fifth embodiment.

[0123] In each of the above embodiments, the white light interference microscope 10 is equipped with a Michelson-type interference objective lens 24. However, as shown in Figure 12, in the fifth embodiment, the white light interference microscope 10 is equipped with a Mirau-type interference objective lens 200. The fifth embodiment has basically the same configuration as the above embodiments, except that it is equipped with an interference objective lens 200 that is different from the interference objective lens 24 of the above embodiments. Therefore, components that are functionally or structurally identical to those in the above embodiments are denoted by the same reference numerals and their descriptions are omitted.

[0124] The Mirau-type interference objective lens 200 comprises an objective lens 200a, a beam splitter 200b, a reference plane 200c, a holder 200d, and a reference plane position adjustment mechanism 202. The beam splitter 200b, the reference plane 200c, and the objective lens 200a are arranged in order along the Z-direction upward from the surface W to be measured. That is, the reference plane 200c is positioned between the objective lens 200a and the beam splitter 200b.

[0125] The objective lens 200a has a focusing function, and focuses the measurement light L1 incident from the beam splitter 22 (see Figure 1) onto the surface to be measured W through the beam splitter 200b.

[0126] The beam splitter 200b corresponds to the interference section of the present invention, splitting a portion of the measurement light L1 incident from the objective lens 200a into reference light L2, transmitting the remaining measurement light L1 downward in the Z direction to the surface to be measured W, and reflecting the reference light L2 toward the reference surface 24c on the upper side in the Z direction.

[0127] The reference surface 200c, for example, is a reflective mirror that reflects the reference light L2 incident from the beam splitter 200b on the lower side in the Z direction back towards the beam splitter 200b. The position of this reference surface 200c in the Z direction can be manually adjusted by, for example, a screw-type reference surface position adjustment mechanism 202. This allows for manual adjustment of the reference optical path length D2 between the beam splitter 200b and the reference surface 200c. As a result, as in the first embodiment described above, the reference optical path length D2 can be made to roughly match the measured optical path length D1 by manual adjustment using the reference surface position adjustment mechanism 202.

[0128] The beam splitter 200b generates interference light L3 from the measurement light L1 returning from the surface to be measured W and the reference light L2 returning from the reference surface 200c, and emits this interference light L3 toward the objective lens 200a on the upper side in the Z direction. After this interference light L3 enters the beam splitter 22 from the objective lens 200a, it is imaged by the camera 34 via the imaging lens 32, as in the embodiments described above.

[0129] The holder 200d, like the holder 24d in each of the above embodiments, is formed in a cylindrical shape extending in the Z direction from a reversibly heat-deformable material such as brass, and houses (holds) the objective lens 200a, the beam splitter 200b, and the reference plane 200c. The portion (region) within this holder 200d that houses the beam splitter 200b and the reference plane 200c becomes the reference plane housing section 200d1.

[0130] In the fifth embodiment, the temperature adjustment unit 26 is located near the reference surface housing unit 200d1 and, under the control of the temperature control unit 100 described above, adjusts the temperature at least between the beam splitter 200b and the reference surface 200c, i.e., the temperature of the reference surface housing unit 200d1. By changing the temperature of the reference surface housing unit 200d1, the reference surface housing unit 200d1 is thermally deformed, and the Z-direction position of the reference surface 200c can be adjusted according to this thermal deformation. As a result, similar to the embodiments described above, the Z-direction position of the reference surface 200c can be adjusted so that the reference optical path length D2 matches the measured optical path length D1.

[0131] The temperature sensor 28 is located near the reference surface housing 200d1 and measures the temperature of at least the reference surface housing 200d1 within the holder 200d, outputting the temperature measurement result to the temperature control unit 100 (see Figure 5). As a result, similar to the embodiments described above, the temperature control unit 100 can perform feedback control to control the temperature adjustment unit 26 so that the reference surface housing 24d2 is adjusted to the target temperature (provisional target temperature) based on the measurement result of the temperature sensor 28.

[0132] In the fifth embodiment, the heat insulating material 30 is provided so as to cover the interference objective lens 200, the temperature adjustment unit 26, and the temperature sensor 28. This allows the reference plane housing unit 200d1 and its vicinity to be stabilized at the target temperature (provisional target temperature). Alternatively, as in the fourth embodiment shown in Figure 11 described above, the heat insulating material 30A may be used to cover only the reference plane housing unit 200d1, the temperature adjustment unit 26, and the temperature sensor 28.

[0133] As described above, in the fifth embodiment as well, the Z-direction position of the reference surface 200c (reference optical path length D2) can be precisely adjusted so that the reference optical path length D2 matches the measured optical path length D1 by controlling the temperature of the reference surface housing section 200d1 (holder 200d) of the Mirau-type interference objective lens 200. As a result, the same effects as in each of the above embodiments can be obtained.

[0134] [others] In the above embodiments, the example described was that the white light interference microscope 10 is equipped with a Michelson-type interference objective lens 24 or a Mirau-type interference objective lens 200. However, various known interference objective lenses, such as the Linik type, may also be provided. Furthermore, each part of the interference objective lens 24 (objective lenses 24a, 200a, beam splitters 24b, 200b, and reference planes 24c, 200c) may be provided separately.

[0135] In each of the above embodiments, the white interference microscope 10 is scanned in the Z direction by the drive mechanism 12, but the object to be scanned is not particularly limited as long as at least the interference objective lenses 24 and 200 can be scanned in the Z direction.

[0136] [Note] As can be seen from the descriptions of the embodiments detailed above, this specification includes disclosures of a variety of technical ideas, including the inventions shown below.

[0137] [Additional note 1] A light source unit that emits white light for measurement, An interference unit that splits a portion of the measurement light emitted from the light source unit into reference light, emits the measurement light onto the surface to be measured, and emits the reference light onto the reference surface, thereby generating interference light between the measurement light returning from the surface to be measured and the reference light returning from the reference surface. A holder for housing the interference portion and the reference surface, formed of a material that reversibly deforms with temperature changes, and which changes the reference optical path length, which is the optical path length of the reference light between the interference portion and the reference surface, in accordance with the temperature changes. When the optical path length of the measurement light between the interference unit and the surface to be measured is defined as the measurement optical path length, the temperature adjustment unit adjusts the temperature of the holder to a target temperature where the reference optical path length matches the measurement optical path length. A three-dimensional shape measuring device equipped with the following features.

[0138] [Additional note 2] A temperature measuring unit for measuring the temperature of the holder, An objective lens that focuses the aforementioned measurement light onto the surface to be measured, A camera that captures the interference light generated by the interference unit, A provisional target temperature control unit controls the temperature adjustment unit to adjust the temperature of the holder to a predetermined provisional target temperature, A focusing control unit that aligns the focus of the objective lens with the surface to be measured, A reference surface position adjustment mechanism that, when the holder is adjusted to the provisional target temperature and the objective lens is focused on the surface to be measured, accepts manual adjustment of the position of the reference surface and adjusts the reference optical path length to roughly match the measurement optical path length, A temperature change control unit controls the temperature adjustment unit to change the temperature of the holder while the reference optical path length is approximately equal to the measured optical path length, While the temperature change control unit changes the temperature of the holder, the image acquisition unit causes the camera to repeatedly capture the interference light and acquires multiple images from the camera. Each time the camera captures the interference light, a temperature acquisition unit acquires the temperature measurement result from the temperature measurement unit, A target temperature determination unit determines the temperature at which the intensity of the interference fringes is maximized as the target temperature, based on the plurality of images acquired by the image acquisition unit and the temperature measurement results acquired by the temperature acquisition unit for each image. A three-dimensional shape measuring device as described in Appendix 1, comprising the above.

[0139] [Additional note 3] A temperature measuring unit for measuring the temperature of the holder, An objective lens that focuses the aforementioned measurement light onto the surface to be measured, A camera that captures the interference light generated by the interference unit, A focusing control unit that aligns the focus of the objective lens with the surface to be measured, A temperature change control unit controls the temperature adjustment unit to change the temperature of the holder while the objective lens is focused on the surface to be measured, While the temperature change control unit changes the temperature of the holder, the image acquisition unit causes the camera to repeatedly capture the interference light and acquires multiple images from the camera. While the temperature change control unit is changing the temperature of the holder, a temperature acquisition unit repeatedly acquires the temperature measurement results of the temperature measurement unit, A target temperature determination unit determines the temperature at which the intensity of the interference fringes is maximized as the target temperature, based on the plurality of images acquired by the image acquisition unit and the plurality of temperature measurement results acquired by the temperature acquisition unit. A three-dimensional shape measuring device as described in Appendix 1, comprising the above.

[0140] [Additional note 4] A temperature measuring unit for measuring the temperature of the holder, A target temperature control unit controls the temperature adjustment unit to adjust the temperature of the holder to the target temperature based on the target temperature and the temperature measurement result of the temperature measurement unit, A three-dimensional shape measuring device according to any one of the appendices 1 to 3, comprising:

[0141] [Additional note 5] The temperature adjustment unit changes the temperature of the reference surface housing portion that houses the reference surface within the holder, The three-dimensional shape measuring device according to Appendix 4, wherein the temperature measuring unit measures the temperature of the reference surface storage unit.

[0142] [Additional note 6] The three-dimensional shape measuring device according to Appendix 5, comprising at least an insulating material covering the reference surface storage section, the temperature measuring section, and the temperature adjustment section.

[0143] [Additional note 7] An adapter section to which a plurality of lens systems, including the holder, the temperature adjustment unit, and the temperature measurement unit, are selectively attached, A target temperature storage unit that stores the correspondence between a plurality of lens systems and the target temperature defined for each lens system, A lens system discrimination unit for identifying the lens system attached to the adapter portion, A target temperature acquisition unit that acquires the target temperature corresponding to the lens system attached to the adapter unit from the target temperature storage unit based on the determination result of the lens system determination unit, Equipped with, The three-dimensional shape measuring apparatus according to any one of the appendices 4 to 6, wherein the target temperature control unit controls the temperature adjustment unit according to the target temperature acquired by the target temperature acquisition unit.

[0144] [Additional note 8] The system includes an objective lens that focuses the measurement light onto the surface to be measured, The interference portion is positioned between the objective lens and the surface to be measured. The three-dimensional shape measuring apparatus according to any one of the appendices 1 to 7, wherein the reference surface is positioned between the objective lens and the interference portion.

[0145] [Additional note 9] A camera that captures the interference light generated by the interference unit, A scanning unit that scans at least the interference portion relative to the surface to be measured in the scanning direction in which the measurement optical path length changes, A three-dimensional shape measuring device according to any one of the appendices 1 to 8, further comprising a shape calculation unit that calculates height information of the surface to be measured for each pixel based on the brightness value of each pixel at the same coordinate in a plurality of images obtained by the camera repeatedly capturing the interference light during scanning by the scanning unit, thereby determining the three-dimensional shape of the surface to be measured.

[0146] [Additional Note 10] An interference unit that splits a portion of the measurement light, which is white light, into a reference light, emits the measurement light onto the surface to be measured and emits the reference light onto the reference surface, and generates interference light between the measurement light returning from the surface to be measured and the reference light returning from the reference surface, An objective lens that focuses the aforementioned measurement light onto the surface to be measured, A holder for housing the interference portion and the reference surface, formed of a material that reversibly deforms with temperature changes, and which changes the reference optical path length, which is the optical path length of the reference light between the interference portion and the reference surface, in accordance with the temperature changes. In a method for adjusting the reference surface position of a three-dimensional shape measuring device, A provisional target temperature adjustment step in which the temperature of the holder is adjusted to a predetermined provisional target temperature, A focusing step in which the focus of the objective lens is aligned with the surface to be measured, With the holder adjusted to the provisional target temperature and the objective lens focused on the surface to be measured, the position of the reference plane is manually adjusted to roughly match the reference optical path length to the measurement optical path length, which is the optical path length of the measurement light between the interference portion and the surface to be measured. After the approximate position adjustment step, a temperature change step is performed to change the temperature of the holder, The imaging step involves repeatedly capturing the interference light while the temperature of the holder is changing, Each time the interference light is imaged in the imaging step, a temperature acquisition step is performed to acquire the temperature of the holder, A target temperature determination step in which, based on the plurality of images obtained in the imaging step and the temperature of the holder for each image obtained in the temperature acquisition step, the temperature at which the intensity of the interference fringes is maximized is determined as the target temperature. A target temperature adjustment step in which the temperature of the holder is adjusted to the target temperature determined in the target temperature determination step, A method for adjusting the reference surface position of a three-dimensional shape measuring device.

[0147] [Additional Note 11] An interference unit that splits a portion of the measurement light, which is white light, into a reference light, emits the measurement light onto the surface to be measured and emits the reference light onto the reference surface, and generates interference light between the measurement light returning from the surface to be measured and the reference light returning from the reference surface, An objective lens that focuses the aforementioned measurement light onto the surface to be measured, A holder for housing the interference portion and the reference surface, formed of a material that reversibly deforms with temperature changes, and which changes the reference optical path length, which is the optical path length of the reference light between the interference portion and the reference surface, in accordance with the temperature changes. In a method for adjusting the reference surface position of a three-dimensional shape measuring device, A focusing step in which the focus of the objective lens is aligned with the surface to be measured, After the focusing step, a temperature change step is performed to change the temperature of the holder, The imaging step involves repeatedly capturing the interference light while the temperature of the holder is changing, Each time the interference light is imaged in the imaging step, a temperature acquisition step is performed to acquire the temperature of the holder, A target temperature determination step in which, based on the plurality of images obtained in the imaging step and the temperature of the holder for each image obtained in the temperature acquisition step, the temperature at which the intensity of the interference fringes is maximized is determined as the target temperature. A temperature adjustment step to adjust the temperature of the holder to the target temperature determined in the target temperature determination step, A method for adjusting the reference surface position of a three-dimensional shape measuring device. [Explanation of Symbols]

[0148] 9 Three-dimensional shape measuring device 10 White light interference microscope 12 Drive mechanism 1 / 14 scale 16 Control device 17 Control section 20 Light source section 22 Beam Splitter 23 Adapter section 24 Interferometric objective lenses 24a objective lens 24b Beam Splitter 24c reference plane 24d holder 24d1 lens barrel 24d2 Reference surface storage compartment 25 Reference plane position adjustment mechanism 26 Temperature adjustment section 28 Temperature Sensor 30 Insulation 30A insulation 32 imaging lenses 34 Cameras 36 Acquired Images 98 Focusing Control Unit 99 Test Patterns 100 Temperature control unit 100a Temperature acquisition part 100b Target temperature storage section 100c Calculation Processing Unit 100d Output Control Unit 100e Temperature Change Control Unit 100f Image acquisition unit 100g Target temperature determination section 100h Lens System Discrimination Unit 100i Target temperature acquisition section 101 Interference fringes 102 Measurement Control Unit 104 Shape calculation section 110 Lens System 112 Databases 200 Interferometric objective lens 200a objective lens 200b Beam Splitter 200c reference plane 200d holder 200d1 Reference surface storage section 202 Reference plane position adjustment mechanism 500 Interferometric Objective Lens 501 Interference section 502 Reference plane 504 Objective Lens 506 Holder D1 Measurement optical path length D2 Reference optical path length L1 Measurement light L2 Reference Light L3 Interferometry W Surface to be measured

Claims

1. A light source unit that emits white light for measurement, An interference unit that splits a portion of the measurement light emitted from the light source unit into reference light, emits the measurement light onto the surface to be measured, and emits the reference light onto the reference surface, thereby generating interference light between the measurement light returning from the surface to be measured and the reference light returning from the reference surface. A holder for housing the interference portion and the reference surface, formed of a material that reversibly deforms with temperature changes, and which changes the reference optical path length, which is the optical path length of the reference light between the interference portion and the reference surface, in accordance with the temperature changes. When the optical path length of the measurement light between the interference unit and the surface to be measured is defined as the measurement optical path length, the temperature adjustment unit adjusts the temperature of the holder to a target temperature where the reference optical path length matches the measurement optical path length. A three-dimensional shape measuring device equipped with the following features.

2. A temperature measuring unit for measuring the temperature of the holder, An objective lens that focuses the aforementioned measurement light onto the surface to be measured, A camera that captures the interference light generated by the interference unit, A provisional target temperature control unit controls the temperature adjustment unit to adjust the temperature of the holder to a predetermined provisional target temperature, A focusing control unit that aligns the focus of the objective lens with the surface to be measured, A reference surface position adjustment mechanism that, when the holder is adjusted to the provisional target temperature and the objective lens is focused on the surface to be measured, accepts manual adjustment of the position of the reference surface and adjusts the reference optical path length to roughly match the measurement optical path length, A temperature change control unit controls the temperature adjustment unit to change the temperature of the holder while the reference optical path length is approximately equal to the measured optical path length, While the temperature change control unit changes the temperature of the holder, the image acquisition unit causes the camera to repeatedly capture the interference light and acquires multiple images from the camera. Each time the camera captures the interference light, a temperature acquisition unit acquires the temperature measurement result from the temperature measurement unit, A target temperature determination unit determines the temperature at which the intensity of the interference fringes is maximized as the target temperature, based on the plurality of images acquired by the image acquisition unit and the temperature measurement results acquired by the temperature acquisition unit for each image. A three-dimensional shape measuring device according to claim 1, comprising:

3. A temperature measuring unit for measuring the temperature of the holder, An objective lens that focuses the aforementioned measurement light onto the surface to be measured, A camera that captures the interference light generated by the interference unit, A focusing control unit that aligns the focus of the objective lens with the surface to be measured, A temperature change control unit controls the temperature adjustment unit to change the temperature of the holder while the objective lens is focused on the surface to be measured, While the temperature change control unit changes the temperature of the holder, the image acquisition unit causes the camera to repeatedly capture the interference light and acquires multiple images from the camera. While the temperature change control unit is changing the temperature of the holder, a temperature acquisition unit repeatedly acquires the temperature measurement results of the temperature measurement unit, A target temperature determination unit determines the temperature at which the intensity of the interference fringes is maximized as the target temperature, based on the plurality of images acquired by the image acquisition unit and the plurality of temperature measurement results acquired by the temperature acquisition unit. A three-dimensional shape measuring device according to claim 1, comprising:

4. A temperature measuring unit for measuring the temperature of the holder, A target temperature control unit controls the temperature adjustment unit to adjust the temperature of the holder to the target temperature based on the target temperature and the temperature measurement result of the temperature measurement unit, A three-dimensional shape measuring device according to any one of claims 1 to 3.

5. The temperature adjustment unit changes the temperature of the reference surface housing portion that houses the reference surface within the holder, The three-dimensional shape measuring device according to claim 4, wherein the temperature measuring unit measures the temperature of the reference surface storage unit.

6. The three-dimensional shape measuring device according to claim 5, comprising at least an insulating material covering the reference surface storage section, the temperature measuring section, and the temperature adjustment section.

7. An adapter section to which a plurality of lens systems, including the holder, the temperature adjustment unit, and the temperature measurement unit, are selectively attached, A target temperature storage unit that stores the correspondence between a plurality of lens systems and the target temperature defined for each lens system, A lens system discrimination unit for identifying the lens system attached to the adapter portion, A target temperature acquisition unit that acquires the target temperature corresponding to the lens system attached to the adapter unit from the target temperature storage unit based on the determination result of the lens system determination unit, Equipped with, The three-dimensional shape measuring apparatus according to claim 4, wherein the target temperature control unit controls the temperature adjustment unit according to the target temperature acquired by the target temperature acquisition unit.

8. The system includes an objective lens that focuses the measurement light onto the surface to be measured, The interference portion is positioned between the objective lens and the surface to be measured. The three-dimensional shape measuring apparatus according to any one of claims 1 to 3, wherein the reference surface is arranged between the objective lens and the interference portion.

9. A camera that captures the interference light generated by the interference unit, A scanning unit that scans at least the interference portion relative to the surface to be measured in the scanning direction in which the measurement optical path length changes, A three-dimensional shape measuring device according to any one of claims 1 to 3, further comprising a shape calculation unit that calculates height information of the surface to be measured for each pixel based on the brightness value of each pixel at the same coordinate in a plurality of images obtained by the camera repeatedly capturing the interference light during scanning by the scanning unit, thereby determining the three-dimensional shape of the surface to be measured.

10. An interference unit that splits a portion of the measurement light, which is white light, into a reference light, emits the measurement light onto the surface to be measured and emits the reference light onto the reference surface, and generates interference light between the measurement light returning from the surface to be measured and the reference light returning from the reference surface, An objective lens that focuses the aforementioned measurement light onto the surface to be measured, A holder for housing the interference portion and the reference surface, formed of a material that reversibly deforms with temperature changes, and which changes the reference optical path length, which is the optical path length of the reference light between the interference portion and the reference surface, in accordance with the temperature changes. In a method for adjusting the reference surface position of a three-dimensional shape measuring device, A provisional target temperature adjustment step in which the temperature of the holder is adjusted to a predetermined provisional target temperature, A focusing step in which the focus of the objective lens is aligned with the surface to be measured, With the holder adjusted to the provisional target temperature and the objective lens focused on the surface to be measured, the position of the reference plane is manually adjusted to roughly match the reference optical path length to the measurement optical path length, which is the optical path length of the measurement light between the interference portion and the surface to be measured. After the approximate position adjustment step, a temperature change step is performed to change the temperature of the holder, The imaging step involves repeatedly capturing the interference light while the temperature of the holder is changing, Each time the interference light is imaged in the imaging step, a temperature acquisition step is performed to acquire the temperature of the holder, A target temperature determination step in which, based on the plurality of images obtained in the imaging step and the temperature of the holder for each image obtained in the temperature acquisition step, the temperature at which the intensity of the interference fringes is maximized is determined as the target temperature. A target temperature adjustment step in which the temperature of the holder is adjusted to the target temperature determined in the target temperature determination step, A method for adjusting the reference surface position of a three-dimensional shape measuring device.

11. An interference unit that splits a portion of the measurement light, which is white light, into a reference light, emits the measurement light onto the surface to be measured and emits the reference light onto the reference surface, and generates interference light between the measurement light returning from the surface to be measured and the reference light returning from the reference surface, An objective lens that focuses the aforementioned measurement light onto the surface to be measured, A holder for housing the interference portion and the reference surface, formed of a material that reversibly deforms with temperature changes, and which changes the reference optical path length, which is the optical path length of the reference light between the interference portion and the reference surface, in accordance with the temperature changes. In a method for adjusting the reference surface position of a three-dimensional shape measuring device, A focusing step in which the focus of the objective lens is aligned with the surface to be measured, After the focusing step, a temperature change step is performed to change the temperature of the holder, The imaging step involves repeatedly capturing the interference light while the temperature of the holder is changing, Each time the interference light is imaged in the imaging step, a temperature acquisition step is performed to acquire the temperature of the holder, A target temperature determination step in which, based on the plurality of images obtained in the imaging step and the temperature of the holder for each image obtained in the temperature acquisition step, the temperature at which the intensity of the interference fringes is maximized is determined as the target temperature. A temperature adjustment step to adjust the temperature of the holder to the target temperature determined in the target temperature determination step, A method for adjusting the reference surface position of a three-dimensional shape measuring device.

Images