Optical Measurement Systems and Probes

Abstract

Provided is an optical measurement system that measures the spectral reflectivity of a sample. This optical measurement system includes: a light source that generates measurement light; a light-receiving unit that receives, as observation light, light that is produced when the sample is irradiated with the measurement light; a probe that is optically connected to the light source and the light-receiving unit and that can be positioned at a discretionary position; and a computation processing unit that measures the spectral reflectivity of a sample ont he basis of the result of detection by the light-receiving unit and that calculates a measurement result based on the measured spectral reflectivity. The probe includes a body part that is gripped by a user, and a flexible part that is capable of bending such that the measurement light can impinge perpendicularly on the sample.

Description

[Technical Field]

[0001] The present invention relates to a portable optical measurement system and a probe for use in the optical measurement system. [Background technology]

[0002] There is a demand for quality control of manufactured products, and to meet this demand, a measuring device and a measuring method for measuring film thickness are known.

[0003] As an example, measuring devices that utilize electromagnetic induction or eddy currents are known. For example, Japanese Patent Laid-Open Publication No. 07-332916 (Patent Document 1) discloses a film thickness meter that accurately measures the film thickness of a magnetic coating using a current of a practical frequency. Also, Japanese Patent Laid-Open Publication No. 06-317401 (Patent Document 2) discloses a handheld dual-use paint thickness gauge that can measure the thickness of both non-ferrous paint on a ferrous substrate and non-conductive paint on a conductive non-ferrous substrate.

[0004] Also known are measuring devices that use ultrasonic waves. For example, Japanese Patent Laid-Open Publication No. 07-167639 (Patent Document 3) discloses a thickness gauge that includes a transducer that emits ultrasonic waves into a coating, receives the ultrasonic waves, and generates a conversion signal proportional to the ultrasonic signal.

[0005] Furthermore, measurement devices that utilize light are also known. For example, International Publication No. 2010 / 013429 (Patent Document 4) discloses a film thickness measurement device that determines the film thickness of a film formed on a substrate surface by measuring spectral reflectance. Also, Japanese Patent Application Laid-Open No. 2007-198771 (Patent Document 5) discloses a film thickness measurement method for a light-transmitting film, which is capable of accurately measuring the film thickness of a light-transmitting film formed on a supporting substrate.

[0006] Among these measurement devices and methods for measuring film thickness, the measurement accuracy of devices using electromagnetic induction or eddy currents and devices using ultrasonic waves is inferior to that of devices using light, so it is preferable to use a measurement device using light for measuring film thickness. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 07-332916 [Patent Document 2] Japanese Patent Application Publication No. 06-317401 [Patent Document 3] Japanese Patent Application Publication No. 07-167639 [Patent Document 4] International Publication No. 2010 / 013429 [Patent Document 5] Japanese Patent Application Laid-Open No. 2007-198771 Summary of the Invention [Problem to be solved by the invention]

[0008] The film thickness measurement device disclosed in the above-mentioned Patent Document 4 is configured so that light from a light source is incident perpendicularly on a measurement target surface having a film, and the light reflected from the measurement target surface is incident on a spectroscopic sensor. In order to make the light from the light source incident perpendicularly on the measurement target surface, the film thickness measurement device is premised on a stationary configuration.

[0009] Furthermore, the film thickness measurement method disclosed in Patent Document 5 is premised on measurements being performed with a constant distance between the lens and the surface of the coating film, but does not teach how to maintain that distance.

[0010] For example, there is a demand for easy measurement at any position on a production line to perform quality control of products. There is also a demand for easy measurement of samples with curved surfaces or complex shapes. However, the above-mentioned prior art does not provide a solution that satisfies these demands.

[0011] One object of the present invention is to provide an optical measurement system or the like that can appropriately measure a sample. [Means for solving the problem]

[0012] According to one aspect of the present invention, there is provided an optical measurement system for measuring the spectral reflectance of a sample. The optical measurement system includes a light source that generates measurement light, a light receiving unit that receives light generated by irradiating the sample with the measurement light as observation light, a probe that is optically connected to the light source and the light receiving unit and can be positioned at any position, and a calculation processing unit that measures the spectral reflectance of the sample based on the detection result by the light receiving unit and calculates a measurement result based on the measured spectral reflectance. The probe includes a main body that is held by a user and a flexible part that can be bent so that the measurement light is incident perpendicularly on the sample.

[0013] The probe may further include a contact portion provided at the tip of the flexible portion for contacting the sample.

[0014] A bendable light guide may be disposed inside the probe. The flexible portion may be made of a flexible material.

[0015] The flexible portion may include a spring coupled to the body portion. The flexible section may include an axis mechanism that is rotatable about two axes that are perpendicular to each other.

[0016] The flexible portion may include a bellows coupled to the body portion. The flexible portion may include a ball joint rotatably connected to the body portion.

[0017] According to another aspect of the present invention, there is provided a probe constituting an optical measurement system for measuring the spectral reflectance of a sample. The optical measurement system includes a light source that generates measurement light, a light receiving unit that receives light generated by irradiating the sample with the measurement light as observation light, and a processing unit that measures the spectral reflectance of the sample based on the detection result by the light receiving unit and calculates a measurement result based on the measured spectral reflectance. The probe includes a main body that is held by a user and a flexible part that can be bent so that the measurement light is incident perpendicularly on the sample. The probe is optically connected to the light source and the light receiving unit and is configured to be positionable at any position. [Effects of the Invention]

[0018] According to an embodiment of the present invention, the sample can be measured appropriately. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram showing a configuration example of an optical measurement system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a schematic diagram showing an example of a functional configuration of the optical measurement system according to the present embodiment. [Figure 3] FIG. 2 is a schematic diagram showing an example of the functional configuration of a processing unit included in the measurement device according to the present embodiment. [Figure 4] FIG. 2 is a schematic diagram showing an example of a probe for a curved surface used in the optical measurement system according to the present embodiment. [Figure 5] FIG. 2 is a schematic diagram showing an example of a cross-sectional structure of a probe for a curved surface used in the optical measurement system according to the present embodiment. [Figure 6] FIG. 2 is a schematic diagram showing an example of the configuration of a probe for a curved surface used in the optical measurement system according to the present embodiment. [Figure 7] FIG. 2 is a schematic diagram showing an example of the configuration of a probe for a curved surface used in the optical measurement system according to the present embodiment. [Figure 8] It is a schematic diagram showing a configuration example of a probe for a curved surface used in the optical measurement system according to this embodiment. [Figure 9] It is a schematic diagram showing a configuration example of a probe for a curved surface used in the optical measurement system according to this embodiment. [Figure 10] It is a schematic diagram showing an example of a cross-sectional structure of a sample to be measured for film thickness by the optical measurement system according to this embodiment. [Figure 11] It is a diagram for explaining an example of a method for calculating measurement reliability in the optical measurement system according to this embodiment. [Figure 12] It is a diagram for explaining another example of a method for calculating measurement reliability in the optical measurement system according to this embodiment. [Figure 13] It is a diagram for explaining yet another example of a method for calculating measurement reliability in the optical measurement system according to this embodiment. [Figure 14] It is a schematic diagram showing an example of a notification form of measurement reliability in the optical measurement system according to this embodiment. [Figure 15] It is a schematic diagram showing an example of a functional configuration provided by the optical measurement system according to this embodiment. [Figure 16] It is a flowchart showing the processing procedure of the optical measurement system according to this embodiment.

Embodiments for Carrying Out the Invention

[0020] Embodiments of the present invention will be described in detail with reference to the drawings. For the same or corresponding parts in the drawings, the same reference numerals are given and the description thereof will not be repeated.

[0021] <A. Optical Measurement System> First, a configuration example of the optical measurement system 1 according to this embodiment will be described. The optical measurement system 1 is an optical measurement device that measures the spectral reflectance of a sample using light. That is, the optical measurement system 1 measures the spectral reflectance of the sample and calculates a measurement result based on the measured spectral reflectance.

[0022] In this specification, "measurement results based on spectral reflectance" includes not only the measured spectral reflectance itself, but also any measurement results calculated using the measured spectral reflectance. Examples of measurement results calculated using the spectral reflectance include film thickness, reflectance characteristics, and object color.

[0023] For convenience, the following description will mainly focus on the configuration for measuring the film thickness of a sample. In this specification, the term "film thickness" refers to the thickness of a specific layer or film contained in a sample. That is, the optical measurement system 1 measures the film thickness, which is the thickness of a layer contained in a sample.

[0024] (a1: System configuration example) 1 is a schematic diagram showing an example of the configuration of an optical measurement system 1 according to the present embodiment. Optical measurement system 1 includes a measurement device 100 and a probe 200 optically connected to measurement device 100.

[0025] In particular, the optical measurement system 1 according to this embodiment is configured as a portable system that allows measurement at any position. In the configuration example shown in Fig. 1, a user can hold the measurement device 100 in one hand and the probe 200 in the other hand to measure any sample at any position. Note that the user does not need to hold the measurement device 100 and / or the probe 200 all the time during measurement. In this way, the probe 200 can be placed at any position.

[0026] The probe 200 has a structure suitable for measuring a sample 4 having an uneven measurement surface. In the example shown in FIG. 1, the sample 4 includes a base 6 and a layer 8 whose film thickness is to be measured. At least a portion of the probe 200 is bendable so as to closely fit the surface shape of the sample 4. More specifically, the probe 200 includes a main body portion 224, a flexible portion 226, and a contact portion 228. In the example shown in FIG. 1, the flexible portion 226 realizes a bendable configuration.

[0027] The measuring device 100 and the probe 200 are connected via an optical fiber 10 and an optical fiber 20. One end of the optical fiber 10 and one end of the optical fiber 20 are detachably connected via a coupler .

[0028] Multiple types of probes 200 may be prepared depending on the shape and characteristics of the sample. In this case, a coupler 28 may be provided to allow the probes 200 to be easily replaced. The coupler 28 is preferably configured to allow the probes 200 to be attached and detached with a single touch. The coupler 28 is preferably configured so that connection, detachment, replacement, etc. do not affect the measurement. However, if only one type of probe 200 is used, the coupler 28 may be omitted.

[0029] The optical fiber 10 is a Y-shaped optical fiber, and a branch fiber 12 and a branch fiber 14 extend from a branch portion 16 of the optical fiber 10.

[0030] (a2: Configuration example of measuring device 100) 2 is a schematic diagram showing an example of the functional configuration of optical measurement system 1 according to the present embodiment. Referring to FIG. 2, measurement device 100 irradiates a sample with light and receives light (reflected light or transmitted light) generated by irradiating the sample with light. In the following description, the light irradiated onto the sample will be referred to as "measurement light" (measurement light 22 shown in FIG. 2), and the light generated by irradiating the sample with light will also be referred to as "observation light" (observation light 24 shown in FIG. 2).

[0031] More specifically, the measuring device 100 includes, as typical components, a light source 102, a spectroscopic measurement unit 104, an output unit 106, an operation unit 108, a calculation processing unit 110, and a power supply unit 130. The components included in the measuring device 100 are packaged and housed in a housing. In the configuration example shown in FIG. 2, the calculation processing unit 110 is mounted in a housing separate from the probe 200.

[0032] The probe 200 is optically connected to the light source 102 and the spectroscopic measurement unit 104. More specifically, the branch fiber 12 is optically connected to the light source 102, and the branch fiber 14 is optically connected to the spectroscopic measurement unit 104. The branch fiber 12 irradiates (projects) the measurement light 22 from the light source 102 onto the sample, and also guides the observation light 24 from the sample to the spectroscopic measurement unit 104.

[0033] The light source 102 has a light emitter such as a white LED or a natural light LED, and generates the measurement light 22. The measurement light 22 generated by the light source 102 is preferably broad light having components over a predetermined wavelength range. In order to miniaturize the measurement device 100, the light source 102 is preferably one that can operate at a relatively low voltage.

[0034] The spectroscopic measurement unit 104 corresponds to a light receiving unit that receives reflected or transmitted light generated when the measurement light 22 is irradiated onto a sample as observation light 24. The spectroscopic measurement unit 104 outputs the intensity of each wavelength of the observation light 24. Typically, the spectroscopic measurement unit 104 includes a diffraction grating that diffracts the observation light 24 incident via the branched fiber 14, and a light receiving element having multiple channels arranged in correspondence with the diffraction grating. The light receiving element is configured as a line sensor or a two-dimensional sensor, and can output the intensity of each wavelength component as a detection result.

[0035] The optical system of the spectroscopic measurement unit 104 may be, for example, a Czerny-Turner type, a Fastie-Ebert type, or a Paschen-Runge type.

[0036] The output unit 106 outputs the calculation results by the calculation processing unit 110 to the user. In particular, the output unit 106 notifies the user of the measurement reliability calculated by the calculation processing unit 110. The output unit 106 may be a display, a touch panel, or an LED that notifies the user of information by image or light, a sound generating unit (speaker) that notifies the user of information by sound, or a vibrator that notifies the user of information by vibration.

[0037] The operation unit 108 accepts user operations and may be any input device such as a touch panel, a keyboard, a mouse, a pen tablet, or buttons.

[0038] The arithmetic processing unit 110 measures the spectral reflectance based on the detection results (intensity for each wavelength of the observation light 24) by the spectroscopic measurement unit 104, and calculates a measurement result 128 based on the measured spectral reflectance. The arithmetic processing unit 110 can measure the film thickness of the sample as the measurement result 128 based on the measured spectral reflectance. In addition, the arithmetic processing unit 110 has a reliability calculation function. That is, the arithmetic processing unit 110 calculates the measurement reliability, which indicates how accurately the calculated film thickness was measured. Furthermore, the arithmetic processing unit 110 also executes various processes, as will be described later.

[0039] As an algorithm for determining the film thickness of a sample, the FFT (Fast Fourier Transform) method, optimization method, or the like can be used.

[0040] The power supply unit 130 supplies power to each component of the measuring device 100, including the arithmetic processing unit 110. The power supply unit 130 adjusts the voltage of the power supplied from an external power source and provides it to each component of the measuring device 100. The power supply unit 130 may have a built-in battery 132 so that it can continue to supply power to each component of the measuring device 100 even if the power supply from the external power source is cut off.

[0041] 3 is a schematic diagram showing an example of the functional configuration of arithmetic processing unit 110 included in measuring device 100 according to the present embodiment. Referring to FIG. 3, arithmetic processing unit 110 includes processor 112, main memory 114, internal interface 116, general-purpose interface 117, network interface 118, and storage 120.

[0042] The processor 112 is typically an arithmetic processing unit such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), and reads one or more programs stored in the storage 120 into the main memory 114 and executes them. The main memory 114 is a volatile memory such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory), and functions as a working memory for the processor 112 to execute the programs.

[0043] The storage 120 is made up of a nonvolatile memory such as a hard disk or flash memory, and stores various programs and data. More specifically, the storage 120 stores an operating system (OS) 122, a measurement program 124, detection results 126, and measurement results 128.

[0044] The operating system 122 provides an environment in which the processor 112 executes the program. The measurement program 124 is executed by the processor 112 to realize the optical measurement method according to the present embodiment. The detection result 126 includes data on the intensity of the observation light 24 for each wavelength output by the spectroscopic measurement unit 104. The measurement result 128 includes the measurement result of the film thickness of the sample obtained by executing the measurement program 124.

[0045] The internal interface 116 mediates data transmission between components included in the measurement device 100 .

[0046] The general-purpose interface 117 is configured by, for example, a USB (Universal Serial Bus) or the like, and mediates data transmission between the device and an external device. The network interface 118 is configured by, for example, a wired LAN or stomachis configured by a wireless LAN or the like and mediates data transmission between external devices. The general-purpose interface 117 and / or the network interface 118 may transmit the detection results 126 stored in the storage 120 to other information processing devices and receive the measurement results 128 processed by other information processing devices. By providing such an interface with other information processing devices, the other information processing devices can take charge of all or part of the necessary analysis processing.

[0047] The measurement program 124 and the like stored in the storage 120 may be installed via any recording medium (for example, an optical disk) or may be downloaded from a server device via the network interface 118 or the like.

[0048] The measurement program 124 may execute processing by calling necessary modules in a predetermined sequence at a predetermined timing among the program modules provided as part of the operating system 122. In such a case, a measurement program 124 that does not include such modules is also included in the technical scope of the present invention. The measurement program 124 may be provided as part of another program.

[0049] All or part of the functions provided by the processor 112 of the arithmetic processing unit 110 executing a program may be realized by a hardwired logic circuit (for example, an FPGA (field-programmable gate array) or an ASIC (application specific integrated circuit)). Also, they may be realized by using an SoC (System on Chip) that integrates a DSP (Digital Signal Processor) and an ISP (Image Signal Processor) in addition to a processor such as a CPU or GPU.

[0050] <B:プローブ200> Next, a configuration example of probe 200 used in optical measurement system 1 according to the present embodiment will be described. Probe 200 used in optical measurement system 1 according to the present embodiment is suitable for measuring sample 4 having a measurement surface that is not flat. Such a probe 200 is also called a curved surface probe.

[0051] In the optical measurement system 1, the user holds the probe 200 and measures the film thickness of the sample 4 while the probe 200 is in contact with (pressed against) the sample 4. To perform an appropriate measurement, it is necessary for the measurement light 22 irradiated from the light-emitting unit of the probe 200 to be reflected by the sample 4, and for the observation light 24 to be incident on the light-emitting and receiving unit of the probe 200. At this time, if the measurement light 22 irradiated from the probe 200 does not enter the sample 4 perpendicularly, the observation light 24 generated by the reflection will not return to the probe 200, and the film thickness of the sample 4 cannot be measured. In particular, if the surface of the sample 4 is curved, it is difficult to press the probe 200 perpendicularly against an arbitrary measurement position on the sample 4.

[0052] Therefore, a probe for curved surfaces can be used in the optical measurement system 1 according to the present embodiment. The probe for curved surfaces is mainly used to measure the film thickness of a sample where the measurement position is on a curved surface.

[0053] Below, several configuration examples of probes for curved surfaces will be described. 4 is a schematic diagram showing an example of probe 200A for curved surfaces used in the optical measurement system according to the present embodiment. Referring to FIG. 4, probe 200A has a bendable flexible section 226 at its tip. Flexible section 226 is made of a soft material. By pressing probe 200A against any measurement position on sample 4, the user can deform flexible section 226 and achieve an appropriate state (i.e., a state in which the light irradiation angle is perpendicular to the measurement surface).

[0054] A contact part 228 that comes into contact with the sample 4 is provided at the tip of the flexible part 226. The light emitting and receiving part 202 is provided at the center of the contact part 228, and a rubber packing 230 is provided on the outer periphery of the exposed surface of the contact part 228. By providing the rubber packing 230, it is possible to improve contact with the sample 4.

[0055] In the measurement state, the sample 4 is irradiated with the measurement light 22 while the contact portion 228 of the probe 200A shown in FIG. 4 is in contact with the sample 4. The observation light 24 generated in the sample 4 is analyzed by the measurement device 100, and the film thickness of the sample 4 is measured.

[0056] Fig. 5 is a schematic diagram showing an example of the cross-sectional structure of probe 200A for curved surfaces used in the optical measurement system according to the present embodiment. Referring to Fig. 5, probe 200A has a light guide path 204 formed therein that is optically connected to optical fiber 20 (see Fig. 4). Light guide path 204 guides light supplied via optical fiber 20 to light projecting and receiving unit 202, and also guides light that has entered light projecting and receiving unit 202 to optical fiber 20.

[0057] The light guide 204 is made of a bendable material such as an optical fiber. The flexible section 226 of the probe 200A is made of a flexible material such as rubber. A terminal mechanism 206 is provided at one end of the light guide 204, and the terminal mechanism 206 communicates with a terminal mechanism 208 that is optically connected to the light projecting and receiving section 202.

[0058] By configuring flexible section 226 from a flexible material and disposing bendable light guide 204 inside, probe 200A suitable for measuring sample 4 having an uneven measurement surface can be realized.

[0059] 4 and 5, probe 200A is configured so that the portion that is pressed against sample 4 can be flexibly moved. By employing such a configuration, even if the measurement position on sample 4 is a curved surface, the user can press probe 200A against sample 4 to appropriately irradiate observation light 24 at any measurement position on sample 4, thereby enabling film thickness measurement of sample 4 to be performed simply and reliably.

[0060] Fig. 6 is a schematic diagram showing an example of the configuration of a probe 200B for curved surfaces used in the optical measurement system according to the present embodiment, in which flexible section 226 is configured using a spring.

[0061] 6(A), the bendable flexible portion 226 of the probe 200B is configured using a spring 232 connected to the main body portion 224. The restoring force of the spring 232 maintains the main body portion 224 and the flexible portion 226 in a predetermined relative relationship. However, when a force exceeding the restoring force of the spring 232 is applied, the flexible portion 226 can assume any angle with respect to the main body portion 224. In other words, the flexible portion 226 is oriented obliquely with respect to the longitudinal direction of the main body portion 224 so as to fit the surface shape of the sample 4.

[0062] 6(B), a light guide path 204 optically connected to the optical fiber 20 (see FIG. 4) is formed inside the probe 200B. The light guide path 204 guides the light supplied via the optical fiber 20 to the light projecting and receiving unit 202, and also guides the light incident on the light projecting and receiving unit 202 to the optical fiber 20.

[0063] The light guide 204 is made of a bendable material such as optical fiber. A terminal mechanism 206 is provided at one end of the light guide 204, and the terminal mechanism 206 communicates with a terminal mechanism 208 that is optically connected to the light projecting and receiving unit 202.

[0064] Light guide 204 is disposed so as to penetrate through the inside of spring 232. The inner diameter of spring 232 is sufficiently larger than the outer diameter of light guide 204, so that light guide 204 and spring 232 do not come into contact with each other even when flexible portion 226 is oriented obliquely with respect to the longitudinal direction of main body portion 224.

[0065] The configuration of the contact portion 228 of the probe 200B is similar to that of the contact portion 228 of the probe 200A shown in FIG.

[0066] 6, the probe 200B employs a structure in which a main body 224 held by the user and a contact portion 228 pressed against the sample 4 are connected by a spring 232. By employing such a structure, the user can press the contact portion 228 at an angle corresponding to any measurement position on the sample 4 without being aware of the angle of the main body 224. This allows the film thickness of the sample 4 to be measured simply and reliably.

[0067] FIG. 7 is a schematic diagram showing an example of the configuration of a probe 200C for curved surfaces used in the optical measurement system according to the present embodiment.

[0068] 7(A), bendable flexible section 226 of probe 200C is configured using an axis mechanism that can rotate around two axes that are perpendicular to each other. More specifically, probe 200C includes plate 234 that rotates about first rotation axis 235 and plate 236 that rotates about second rotation axis 237. Note that the two plates 234 are provided to face each other, and similarly, the two plates 236 are provided to face each other.

[0069] One end of plate 234 is connected to main body 224, and the other end of plate 234 is connected to link member 238. Furthermore, one end of plate 236 is connected to link member 238, and the other end of plate 236 is connected to a member including contact portion 228.

[0070] Since the first rotation axis 235 of the plate 234 and the second rotation axis 237 of the plate 236 are both freely rotatable, the flexible portion 226 can be angled at any angle relative to the main body portion 224 by an external force applied by the user. That is, the flexible portion 226 is oriented obliquely relative to the longitudinal direction of the main body portion 224 so as to fit the surface shape of the sample 4.

[0071] 7(B), a light guide path 204 optically connected to the optical fiber 20 (see FIG. 4) is formed inside the probe 200C. The light guide path 204 guides the light supplied via the optical fiber 20 to the light projecting and receiving unit 202, and also guides the light incident on the light projecting and receiving unit 202 to the optical fiber 20.

[0072] The light guide 204 is made of a bendable material such as optical fiber. A terminal mechanism 206 is provided at one end of the light guide 204, and the terminal mechanism 206 communicates with a terminal mechanism 208 that is optically connected to the light projecting and receiving unit 202.

[0073] Light guide 204 is disposed so as to pass through a gap formed in the center of link member 238. The inner diameter of the gap in link member 238 is sufficiently larger than the outer diameter of light guide 204, so even when flexible section 226 is oriented obliquely with respect to the longitudinal direction of main body section 224, light guide 204 does not interfere with other members.

[0074] The configuration of the contact portion 228 of the probe 200C is similar to that of the contact portion 228 of the probe 200A shown in FIG.

[0075] 7, the probe 200C employs a structure in which a main body 224 held by the user and a contact part 228 pressed against the sample 4 are connected by a joint consisting of two axes. By employing such a structure, the user can press the contact part 228 at an angle corresponding to any measurement position on the sample 4 without being aware of the angle of the main body 224. This allows the film thickness of the sample 4 to be measured simply and reliably.

[0076] FIG. 8 is a schematic diagram showing an example of the configuration of a probe 200D for curved surfaces used in the optical measurement system according to the present embodiment.

[0077] 8A, the bendable flexible portion 226 of the probe 200D is configured using a bellows 240 connected to the main body portion 224. More specifically, the probe 200 D includes a bellows 240 for connecting the main body portion 224 with the flexible portion 226 and the contact portion 228. The bellows 240 has a predetermined rigidity and flexibility, so that the main body portion 224 and the flexible portion 226 are maintained in a predetermined relative relationship. However, by applying a force according to the flexibility of the bellows 240, the flexible portion 226 can assume any angle with respect to the main body portion 224. In other words, the flexible portion 226 faces obliquely with respect to the longitudinal direction of the main body portion 224 so as to fit the surface shape of the sample 4.

[0078] 8(B), a light guide path 204 optically connected to the optical fiber 20 (see FIG. 4) is formed inside the probe 200D. The light guide path 204 guides the light supplied via the optical fiber 20 to the light projecting and receiving unit 202, and also guides the light incident on the light projecting and receiving unit 202 to the optical fiber 20.

[0079] The light guide 204 is made of a bendable material such as optical fiber. A terminal mechanism 206 is provided at one end of the light guide 204, and the terminal mechanism 206 communicates with a terminal mechanism 208 that is optically connected to the light projecting and receiving unit 202.

[0080] Light guide 204 is disposed so as to penetrate the internal space of bellows 240. The inner diameter of bellows 240 is sufficiently larger than the outer diameter of light guide 204, so even when flexible portion 226 is oriented obliquely with respect to the longitudinal direction of main body 224, light guide 204 does not interfere with other members.

[0081] The configuration of the contact portion 228 of the probe 200D is similar to that of the contact portion 228 of the probe 200A shown in FIG.

[0082] 8, the probe 200D employs a structure in which a main body 224 held by the user and a contact part 228 pressed against the sample 4 are connected by a bellows 240 made of a cylindrical flexible material. By employing such a structure, the user can press the contact part 228 at an angle corresponding to any measurement position on the sample 4 without being aware of the angle of the main body 224. This allows the film thickness of the sample 4 to be measured simply and reliably.

[0083] FIG. 9 is a schematic diagram showing an example of the configuration of a probe 200E for curved surfaces used in the optical measurement system according to the present embodiment.

[0084] figure 9 For reference, the bendable flexible portion 226 of the probe 200E is configured using a ball joint 242 rotatably connected to the main body portion 224. More specifically, the probe 200E includes the ball joint 242 for connecting the main body portion 224 with the flexible portion 226 and the contact portion 228. The ball joint 242 has a predetermined resistance, so that the main body portion 224 and the flexible portion 226 are maintained in a predetermined relative relationship. When a force exceeding the resistance of the ball joint 242 is applied, the flexible portion 226 can assume any angle with respect to the main body portion 224. That is, the flexible portion 226 is oriented obliquely with respect to the longitudinal direction of the main body portion 224 so as to conform to the surface shape of the sample 4.

[0085] figure 9 4, a light guide path 204 optically connected to the optical fiber 20 (see FIG. 4) is formed inside the probe 200E. The light guide path 204 guides the light supplied via the optical fiber 20 to the light projecting and receiving unit 202, and also guides the light incident on the light projecting and receiving unit 202 to the optical fiber 20.

[0086] The light guide path 204 is made of a flexible material such as an optical fiber. A terminal mechanism 206 is provided at one end of the light guide path 204, and the terminal mechanism 206 communicates with a terminal mechanism 208 optically connected to the light transmitting / receiving unit 202.

[0087] The light guide path 204 is arranged to penetrate through the inside of the ball joint 242. Since the internal hole of the ball joint 242 is maintained regardless of the positional relationship between the main body portion 224 and the flexible portion 226, the light guide path 204 will not be damaged.

[0088] Note that the configuration of the contact portion 228 of the probe 200E is the same as that of the contact portion 228 of the probe 200A shown in FIG. 5.

[0089] As shown in FIG. 9, the probe 200E adopts a structure in which a main body portion 224 held by a user and a contact portion 228 pressed against the sample 4 are connected by a ball joint 242. By adopting such a structure, the user can press the contact portion 228 at an angle corresponding to an arbitrary measurement position of the sample 4 without being conscious of the angle of the main body portion 224. Thereby, the film thickness measurement of the sample 4 can be performed simply and reliably.

[0090] By adopting the probe 200 having the structure as described above, the film thickness of the sample 4 having a non-flat measurement surface can be measured. Note that, as long as the contact portion 228 can change in an arbitrary direction via the flexible portion 226 with respect to the main body portion 224 held by the user, it is not limited to the above-described structure, and any structure of the probe 200 may be adopted.

[0091] <C. Example of Film Thickness Measurement Processing> Next, an example of the film thickness measurement process by the optical measurement system 1 according to this embodiment will be described.

[0092] 10 is a schematic diagram showing an example of the cross-sectional structure of a sample 4, which is the target of film thickness measurement by the optical measurement system 1 according to the present embodiment. For ease of explanation, FIG. 10 shows sample 4, in which a coating layer 41 is formed on a substrate layer 42. It is assumed that coating layer 41 is in contact with an air layer 40.

[0093] Referring to FIG. 10, the reflected light generated when the measurement light 22 emitted from the probe 200 is reflected at the interface between the coating layer 41 and the substrate layer 42 will be considered. In the following explanation, each layer will be represented by a subscript i. That is, the air layer 40 will be represented by a subscript "0", the coating layer 41 of the sample by a subscript "1", and the substrate layer 42 by a subscript "2". The refractive index of each layer will be represented by a subscript i, and the refractive index n i It is expressed as:

[0094] Different refractive indices n i Since light is reflected at the interface of layers with different refractive indices, the amplitude reflectance (Fresnel coefficient) r of the P-polarized and S-polarized components at each interface between the i-th layer and the i+1-th layer is (P) i,i+1 ,r (S) i,i+1 can be expressed as follows:

[0095]

number

[0096] where φ i is the angle of incidence at the i-th layer. This angle of incidence φ i can be calculated from the angle of incidence of the measurement light 22 on the uppermost air layer 40 by Snell's law as follows:

[0097] N0sinφ0=N i sinφ i In a layer having a thickness that allows light to interfere, light reflected with the amplitude reflectance expressed by the above formula travels back and forth within the layer many times. As a result, the optical path lengths of light directly reflected at the interface with an adjacent layer and light after multiple reflections within the layer differ, resulting in different phases, and optical interference occurring on the surface of the coating layer 41. To show the optical interference effect within each layer, the phase angle β of light within the i-layer is i By introducing, it can be expressed as follows:

[0098]

number

[0099] where d i denotes the thickness of the i-layer, and λ denotes the wavelength of the incident light. For simplicity, when the light is irradiated perpendicularly to the sample 4, that is, when the incident angle is φ i = 0, there is no distinction between P-polarized light and S-polarized light, and the amplitude reflectance at the interface between each layer and the phase angle β1 of the film thickness are as follows:

[0100]

number

[0101] Furthermore, the reflectance R for sample 4 shown in FIG.

[0102]

number

[0103] In the above equation, when considering a frequency transformation (Fourier transform) of the phase angle β1, the phase factor cos2β1 becomes nonlinear with respect to the reflectance R. Therefore, this phase factor cos2β1 is transformed into a linear function. As an example, this reflectance R is transformed as shown in the following equation, and a unique variable, the wavenumber transformed reflectance R', is defined.

[0104]

number

[0105] This wave number transformed reflectance R' is a linear expression for the phase factor cos2β1, and has linearity. a is the intercept at the wavenumber-transformed reflectance R', and R b is the slope of the wavenumber-transformed reflectance R'. In other words, this wavenumber-transformed reflectance R' is a function for linearizing the value of the reflectance R at each wavelength with respect to the phase factor cos2β1 related to the frequency conversion. Note that a function such as 1 / (1-R) ​​may be used as the function for linearizing the phase factor.

[0106] Therefore, the wave number K1 in the target coating layer 41 can be defined as follows:

[0107]

number

[0108] Here, the propagation characteristics of electromagnetic waves within coating layer 41 depend on wave number K1. That is, light with wavelength λ in a vacuum travels at a slower speed within the layer, and so its wavelength also increases from λ to λ / n1. Taking into account this wavelength dispersion phenomenon, the wave number conversion reflectance R' is defined as follows:

[0109]

number

[0110] From this relationship, when the wavenumber transformed reflectance R' is frequency transformed (Fourier transformed) with respect to the wavenumber K, a peak appears in the periodic component corresponding to the film thickness d1 of the coating layer 41, and by identifying the position of this peak, the film thickness d1 of the coating layer 41 can be calculated.

[0111] That is, the correspondence between the spectral reflectance measured from Sample 4 and the reflectance at each wavelength is converted into the correspondence (wavenumber distribution characteristics) between the wavenumber calculated from each wavelength and the wavenumber-converted reflectance R' calculated according to the above relational expression. A spectrum is calculated by frequency-converting a function of the wavenumber-converted reflectance R' including this wavenumber K with respect to the wavenumber K, and based on the peak appearing in this calculated spectrum, the film thickness d1 of the coating layer 41 constituting Sample 4 is calculated. This means obtaining the amplitude values of each wavenumber component included in the wavenumber distribution characteristics and calculating the film thickness d1 of the coating layer 41 based on the wavenumber component with a large amplitude value among them. <00004​​​​​​​​​​​​​​​​​​​​In this specification, "measurement reliability" refers to the degree to which a measured or calculated measurement result (for example, film thickness) is accurately measured.

[0117] Any method can be used to calculate the measurement reliability, but several calculation methods will be described as typical examples.

[0118] (d1: Calculation method of measurement reliability using FFT method) First, a method suitable for calculating the film thickness using the FFT method will be described.

[0119] Fig. 11 is a diagram for explaining an example of a method for calculating measurement reliability in optical measurement system 1 according to the present embodiment. Fig. 11 shows a method for calculating measurement reliability when calculating the film thickness of a sample using the FFT method.

[0120] Referring to FIG. 11, the spectral reflectance is calculated from the observation light 24 measured from the sample 4, and converted into the wavenumber-converted reflectance R′ as described above. Then, a frequency conversion (Fourier transform) is performed on the wavenumber K, thereby calculating a spectrum (hereinafter also referred to as a “power spectrum”) with the film thickness on the horizontal axis and the power on the vertical axis.

[0121] In this way, in the FFT method, the film thickness of the sample 4 is calculated based on the peaks that appear in the spectrum calculated by frequency-converting the spectral reflectance or spectral transmittance.

[0122] The measurement reliability can be calculated based on the peak that appears at the position corresponding to the film thickness of the sample 4 for the calculated power spectrum. That is, the more appropriate the measurement conditions, the larger and sharper the peak appears in the power spectrum. Therefore, the measurement reliability can be calculated according to the size or sharpness of the peak.

[0123] 11, the area indicated by the peak that appears at the position corresponding to the film thickness of sample 4 (peak area) and the area of ​​the other part (noise area) may be calculated, and the ratio of the calculated areas may be used as the measurement reliability. Specifically, the measurement reliability can be calculated according to the following formula:

[0124] Measurement reliability = peak area / noise area Alternatively, any of the following formulas may be used:

[0125] Measurement reliability = peak area / (peak area + noise area) Measurement reliability = (peak area - noise area) / (peak area + noise area) Alternatively, the measurement reliability may be calculated based on the peak height (power magnitude). Specifically, the measurement reliability can be calculated according to any of the following formulas.

[0126] Measurement reliability = peak height / noise height Measurement reliability = peak height / (peak height + noise height) Measurement reliability = (peak height - noise height) / (peak height + noise height) In this way, when calculating the film thickness of a sample using the FFT method, the measurement reliability can be calculated based on the magnitude of the peaks that appear in the calculated power spectrum.

[0127] (d2: Calculation method of measurement reliability using optimization method) Next, a method suitable for calculating the film thickness by the optimization method will be described.

[0128] The optimization method is a method of fitting the parameters of a model that indicates the spectral reflectance so that they match the actually measured spectral reflectance (or the wavenumber-transformed reflectance R' obtained by converting the actually measured spectral reflectance).

[0129] In this way, the optimization method calculates the film thickness of the sample by fitting the model parameters that indicate the spectral reflectance or spectral transmittance so that they match the spectral reflectance or spectral transmittance calculated based on the observed light 24.

[0130] The reliability of the measurement can be calculated based on the degree to which the spectral reflectance (theoretical value) calculated using a model defined by parameters determined by the optimization method matches the actually measured spectral reflectance (i.e., the degree of agreement with the actually measured spectral reflectance, or the degree of deviation from the actually measured spectral reflectance).

[0131] More specifically, the correlation coefficient between the actually measured spectral reflectance and the spectral reflectance (theoretical value) calculated using a model defined by parameters determined by the optimization method may be determined as the measurement reliability.

[0132] Alternatively, the reciprocal of the square error between the actually measured spectral reflectance and the spectral reflectance (theoretical value) calculated using a model defined by parameters determined by the optimization method may be determined as the measurement reliability.

[0133] In this way, when calculating the film thickness of a sample using the optimization method, the measurement reliability can be calculated based on the degree of agreement between the spectral reflectance calculated using a model defined by the determined parameters and the actually measured spectral reflectance. In other words, when calculating the film thickness of a sample using the optimization method, the measurement reliability can be calculated based on the determined fitting results.

[0134] (d3: Calculation method of measurement reliability based on reflectance) FIG. 12 is a diagram for explaining another example of the method for calculating the measurement reliability in optical measurement system 1 according to the present embodiment.

[0135] FIG. 12(A) shows an example of spectral reflectance when measurement conditions are poor, and FIG. 12(B) shows an example of spectral reflectance when measurement conditions are appropriate. As shown in FIG. 12, when measurement conditions are appropriate, the amplitude of the spectral reflectance (the difference between the maximum and minimum reflectance values) is relatively large. Therefore, the measurement reliability may be calculated based on the amplitude of the spectral reflectance. For example, the amplitude of the spectral reflectance measured with the reference cap attached may be used as a reference, and the ratio of the reference amplitude to the reference amplitude may be calculated as the measurement reliability.

[0136] The reference cap is used for calibrating the optical measurement system 1. The reference cap can also be used to prevent dust and other particles from entering the probe 200 when the probe 200 is stored.

[0137] When the reference cap is attached to the probe 200, a mirror is provided at a position facing the light projecting and receiving unit 202 of the probe 200. The mirror reflects the measurement light 22 emitted from the light projecting and receiving unit 202 and returns it to the light projecting and receiving unit 202 as observation light 24. The observation light 24 measured with the reference cap attached to the probe 200 is used as a reference for reflectance. In other words, the observation light 24 measured with the reference cap 30 attached to the probe 200 is acquired as a reference signal.

[0138] In this way, the measurement reliability can be calculated based on the amplitude of the measured spectral reflectance, without relying on an algorithm for calculating the film thickness of the sample.

[0139] Furthermore, the measurement reliability may be calculated from the value of the reflectance (amplitude reflectance). For example, the reflectance may be output as the measurement reliability as is, or the measurement reliability may be calculated by inputting the reflectance into a predetermined function (for example, a function whose output monotonically increases with respect to the reflectance).

[0140] If the angle or distance of the probe 200 relative to the sample is not appropriate, or if there is a large amount of light diffusion on the sample surface, the calculated reflectance (amplitude reflectance) will be small, which means that the measurement reliability is low.

[0141] In this way, the measurement reliability can be calculated based on the magnitude of the measured reflectance (amplitude reflectance) without relying on an algorithm for calculating the film thickness of the sample.

[0142] Furthermore, the measurement reliability may be calculated from the variation in reflectance (amplitude reflectance). For example, if the user does not hold the probe 200 steadily and the angle or distance of the probe 200 fluctuates, or if there is a fine film thickness distribution on the sample surface, the variation in the calculated reflectance (amplitude reflectance) will be large, which means that the measurement reliability is low.

[0143] FIG. 13 is a diagram for explaining yet another example of the method for calculating measurement reliability in optical measurement system 1 according to the present embodiment.

[0144] Fig. 13(A) shows an example of reflectance when measurement is unstable, and Fig. 13(B) shows an example of reflectance when measurement is stable. As shown in Fig. 13, when measurement is stable, the measured reflectance is also stable, so the variation is relatively small. Therefore, the measurement reliability may be calculated based on the magnitude of the variation in reflectance.

[0145] More specifically, the measurement reliability may be calculated from the standard deviation or variance of the reflectance measured a predetermined number of times from the most recent measurement.

[0146] In this way, the measurement reliability can be calculated based on the variation in the measured reflectance (amplitude reflectance) without relying on an algorithm for calculating the film thickness of the sample.

[0147] (d4: Method for calculating measurement reliability based on reference signal) The measurement reliability may be calculated based on a reference signal, which is the observation light 24 measured with the probe 200 fitted with a reference cap.

[0148] For example, if the light source 102 deteriorates due to use, the amount of measurement light emitted by the light source 102 decreases. When this occurs, it can be considered that the measurement reliability has decreased. Therefore, the measurement reliability may be calculated based on the magnitude of the reference signal before or immediately after product shipment and the magnitude of the reference signal during actual measurement.

[0149] More specifically, the ratio of the magnitude of the reference signal during actual measurement to the magnitude of the reference signal before or immediately after product shipment may be calculated as the measurement reliability.

[0150] In this way, the reliability of the measurement can be calculated based on the magnitude of the measured reference signal, without relying on an algorithm for calculating the film thickness of the sample.

[0151] (d5: Method for calculating measurement reliability based on the variability of measurement results) The measurement reliability may be calculated from the variation in the measurement results (for example, film thickness). For example, if the user does not hold the probe 200 steadily and the angle or distance of the probe 200 fluctuates, or if there is a minute film thickness distribution on the sample surface, the variation in the measured or calculated measurement results will be large, which means that the measurement reliability is low.

[0152] 13(A) and 13(B) above, when the measurement is stable, the measured or calculated measurement results are also stable, and the variability is relatively small. Therefore, the measurement reliability may be calculated based on the magnitude of the variability in the measured or calculated measurement results.

[0153] More specifically, the measurement reliability may be calculated from the standard deviation or variance of a predetermined number of measurement results from the most recent measurement.

[0154] In this way, the measurement reliability can be calculated based on the variability of the measured or calculated measurement results, without relying on an algorithm for calculating the film thickness of the sample.

[0155] (d6: Method using multiple types of measurement reliability) As described above, the measurement reliability can be calculated using multiple methods. Therefore, multiple measurement reliabilities calculated using different methods may be combined to calculate the final measurement reliability. In this case, the multiple target measurement reliabilities may be normalized and then simply averaged to calculate the final measurement reliability.

[0156] Alternatively, the final measurement reliability may be calculated by multiplying each of the target measurement reliabilities by a corresponding weighting factor.Furthermore, the weighting factor may be changed depending on the conditions.

[0157] In this way, by using a plurality of types of measurement reliability to determine the final measurement reliability, the accuracy of the measurement reliability can be improved.

[0158] (d7: Method of notification) Any method may be used to notify the user of the measurement reliability, but a notification sound indicating the measurement reliability may be used so that the user can easily recognize the measurement reliability while holding and scanning the probe 200. For example, the level of measurement reliability may be associated with the occurrence cycle or occurrence frequency of the notification sound as follows:

[0159] Measurement reliability: Low Beep (silent) Beep Measurement reliability: Medium Beep (silent) Beep Measurement reliability: High Beep beep (silent) Beep beep In this way, a notification sound corresponding to the level of measurement reliability may be generated. Such notification sound allows the user to grasp the measurement reliability in real time, and thus adjust the probe 200 to an appropriate angle, distance, and position (measurement position). By such adjustment, the film thickness of the sample 4 can be obtained under appropriate measurement conditions.

[0160] In the above description, the notification form in which the degree of measurement reliability is associated with the occurrence cycle or occurrence frequency of the notification sound is exemplified, but the present invention is not limited to this and any other notification method can be adopted.

[0161] When the measurement reliability is notified by sound (i.e., when the user recognizes the measurement reliability through hearing), one or more of the volume, pitch, and tone may be changed according to the calculated level of the measurement reliability. The user can easily recognize the change in the measurement reliability by the change in the volume, pitch, or tone of the notification sound.

[0162] Furthermore, notifications are not limited to sound notifications, but can also be made using vibrations, light, images, and the like.

[0163] For example, when the measurement reliability is notified by vibration (i.e., when the user recognizes the measurement reliability by touch), a vibrator may be provided in the measuring device 100 and / or the probe 200, and one or more of the vibration strength, vibration period, and vibration interval of the vibrator may be changed according to the calculated level of the measurement reliability. The user can easily recognize the change in the measurement reliability by the change in the vibration they feel.

[0164] Furthermore, when the measurement reliability is notified by light or an image (i.e., when the user visually recognizes the measurement reliability), an optional light-emitting device may be provided in the measurement device 100 and / or the probe 200, and the light-emitting state of the light-emitting device may be changed depending on the level of the calculated measurement reliability. That is, at least one of light and an image indicating the measurement reliability may be output from the output unit 106. The user can easily recognize changes in the measurement reliability by the light or image that enters their eyes.

[0165] Fig. 14 is a schematic diagram showing an example of a notification form of measurement reliability in optical measurement system 1 according to the present embodiment. Fig. 14(A) to Fig. 14(C) show an example of a notification form when display 1060 is used as output unit 106 of measurement device 100.

[0166] 14(A) displays a film thickness measurement value 1062 and a status bar 1064 indicating the measurement reliability on the display 1060 of the measurement device 100. By checking the status bar 1064 indicating the measurement reliability, the user can obtain the film thickness measurement value 1062 while recognizing the measurement reliability.

[0167] 14(B) displays a film thickness measurement value 1062 and a numerical value 1066 indicating the measurement reliability on the display 1060 of the measuring device 100. By checking the numerical value 1066 indicating the measurement reliability, the user can obtain the film thickness measurement value 1062 while recognizing the measurement reliability.

[0168] 14(C) displays a film thickness measurement value 1062 on a display 1060 of the measuring device 100, and the measuring device 100 is provided with an indicator 1068 that indicates the measurement reliability. The indicators 1068 light up in numbers corresponding to the calculated level of measurement reliability. By checking the indicators 1068 that indicate the measurement reliability, the user can obtain the film thickness measurement value 1062 while recognizing the measurement reliability.

[0169] Not limited to the notification forms shown in FIGS. 14(A) to 14(C), the measurement reliability can be notified to the user in any form.

[0170] <E. Functional Block Diagram> FIG. 15 is a schematic diagram showing an example of the functional configuration provided by the optical measurement system 1 according to the present embodiment. Each function shown in FIG. 15 is typically realized by the processor 112 of the arithmetic processing unit 110 of the measurement device 100 executing the measurement program 124.

[0171] Referring to FIG. 15, the measurement device 100 includes, as a functional configuration, a buffer 150, a wave number conversion unit 152, a Fourier transform unit 154, a peak search unit 156, a film thickness determination unit 158, a measurement reliability calculation unit 160, and an output processing unit 162.

[0172] The buffer 150 stores the detection results (intensity for each wavelength of the observation light 24) from the spectroscopic measurement unit 104.

[0173] The wave number conversion unit 152 calculates the spectroscopic reflectance from the intensity for each wavelength of the observation light 24 stored in the buffer 150, and calculates the wave number conversion reflectance from the calculated spectroscopic reflectance.

[0174] The Fourier transform unit 154 Fourier-transforms the wave number conversion reflectance calculated by the wave number conversion unit 152.

[0175] The peak search unit 156 searches for peaks included in the power spectrum calculated by the Fourier transform by the Fourier transform unit 154, and outputs the position (film thickness) of the power spectrum corresponding to the searched peaks. That is, the peak search unit 156 corresponds to a film thickness calculation unit that calculates the film thickness of the sample from the spectroscopic reflectance (or spectroscopic transmittance) calculated based on the detection results by the spectroscopic measurement unit 104.

[0176] The measurement reliability calculation unit 160 calculates a measurement reliability indicating how appropriately the film thickness calculated by the peak search unit 156 is measured. More specifically, the measurement reliability calculation unit 160 calculates the measurement reliability based on the power spectrum calculated by the Fourier transform by the Fourier transform unit 154.

[0177] When a predetermined condition is satisfied, the film thickness determination unit 158 determines the film thickness output from the peak search unit 156 as a measurement result. The predetermined condition may include that the user has operated the operation unit 108, that the measurement reliability in a predetermined period becomes the maximum value, that the measurement reliability exceeds a predetermined threshold value, and the like. Thus, the film thickness determination unit 158 typically determines the film thickness at the time when the measurement reliability satisfies the predetermined condition as the measurement result.

[0178] The output processing unit 162 is in charge of the process of outputting, from the output unit 106, the film thickness output from the peak search unit 156, the measurement reliability output from the measurement reliability calculation unit 160, the measurement result (film thickness) output from the film thickness determination unit 158, and the like. The output processing unit 162 notifies the user, via the output unit 106, of the measurement reliability calculated by the measurement reliability calculation unit 160.

[0179] Although FIG. 15 shows a configuration example in the case of calculating the film thickness by the FFT method as a typical example, when measuring the film thickness by the optimization method, a fitting unit that fits a model including the film thickness of the sample as a parameter and the actually measured reflectance (or transmittance) may be provided.

[0180] <F. Processing Procedure> FIG. 16 is a flowchart showing the processing procedure of the optical measurement system 1 according to the present embodiment. Each step shown in FIG. 16 is typically realized by the processor 112 of the arithmetic processing unit 110 of the measurement device 100 executing the measurement program 124.

[0181] 16, when an instruction to start measurement is received (YES in step S100), the measurement apparatus 100 issues a drive command to the light source 102 to enable irradiation of the measurement light 22 from the light source 102 (step S102). In this way, the measurement apparatus 100 irradiates the sample 4 with the measurement light 22 generated by the light source 102 through the probe 200, which can be placed at any position.

[0182] The measurement device 100 then calculates the film thickness of the sample 4 based on the detection results (intensity for each wavelength of the observation light 24) output when the observation light 24 from the sample 4 is incident on the spectroscopic measurement unit 104 (step S104). In this way, the measurement device 100 receives the reflected light (or transmitted light) generated by irradiating the sample 4 with the measurement light 22 as observation light in the spectroscopic measurement unit 104, and calculates the film thickness of the sample 4 from the spectral reflectance (or spectral transmittance) calculated based on the detection results by the spectroscopic measurement unit 104.

[0183] Furthermore, measuring device 100 calculates the measurement reliability based on the data used in the process of calculating the film thickness of sample 4 (step S106). In this way, measuring device 100 calculates the measurement reliability indicating how accurately the calculated film thickness was measured. Then, measuring device 100 generates a notification sound corresponding to the level of the calculated measurement reliability (step S108).

[0184] When an instruction to output the measurement results is given by a trigger switch or the like (YES in step S110), the measurement device 100 determines the film thickness of the sample 4 calculated in the current calculation cycle as the measurement result (step S112). If an instruction to output the measurement results is not given (NO in step S110), the processing of step S112 is skipped.

[0185] If the measurement end is instructed (YES in step S114), measuring apparatus 100 ends the film thickness measurement process, and if not (NO in step S114), it repeats the processes from step S104 onwards.

[0186] Note that the processes of steps S106 and S108 may be omitted. In this case, in step S110, it is determined whether the conditions for outputting as measurement results are satisfied.

[0187] <G. Modified Example> The above-described measuring device 100 may be implemented using a small personal computer. In this case, many components included in the measuring device 100 will be included in the personal computer. Alternatively, the above-described measuring device 100 may be implemented using a smartphone, a tablet, or the like.

[0188] Although the configuration example in which the measuring device 100 of the optical measurement system 1 executes the necessary processes has been described, it is not limited to this. For example, the processes may be shared by a plurality of processing devices, or a part of the processes may be assigned to the probe 200. Furthermore, all or part of the necessary processes may be assigned to computing resources (so-called cloud) on a network not shown.

[0189] When many computing resources are available, machine learning may be performed using the measurement results acquired in the past and / or the measurement results acquired by other optical measurement systems 1, and the user may be notified of the optimal conditions related to film thickness measurement using the learned model obtained by the machine learning.

[0190] The implementation method of the optical measurement system 1 according to the present embodiment may be in any form, and may be appropriately implemented using the technologies available in each era.

[0191] Note that not only the above-described probe 200 but any shape of the probe 200 may be adopted. For example, the probe 200 may be configured to be changeable to different types according to the sample 4.

[0192] Examples of the multiple types of probes 200 include (1) stethoscope-type probes, (2) pen-type probes, (3) V-groove-type probes, (4) L-shaped probes, (5) mini-spot probes, (6) non-contact probes, (7) movable-tip probes, (8) submerged probes, (9) oil film probes, and (10) multi-angle probes.

[0193] Also, although a configuration example has been shown in which the measuring device 100 and the probe 200 are separate, the measuring device 100 and the probe 200 may be connected to each other, or the measuring device 100 and the probe 200 may be integrated together. Furthermore, although a configuration example has been shown in which the measuring device 100 and the probe 200 are optically connected, the measuring device 100 and the probe 200 may be wireless.

[0194] <H.まとめ> In the optical measurement system according to the present embodiment, by using a probe including a bendable flexible portion, optical measurement values ​​can be easily obtained even for samples with curved surfaces. A user holds the probe according to the present embodiment and presses the probe against any measurement position on the sample, thereby measuring the optical measurement value at that measurement position. At this time, because the probe includes a bendable flexible portion, the contact portion pressed against the sample can flexibly move. This allows light from the light source to be incident perpendicularly on the sample, even for samples with curved surfaces, thereby achieving more accurate optical measurement of the sample.

[0195] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0196] 1 Optical measurement system, 4 Sample, 6 Base, 8 Layer, 10, 20 Optical fiber, 12, 14 Branch fiber, 16 Branch section, 22 Measurement light, 24 Observation light, 28 Coupler, 30 Reference cap, 40 Air layer, 41 Coating layer, 42 Substrate layer, 100 Measurement device, 102 Light source, 104 Spectroscopic measurement section, 106 Output section, 108 Operation section, 110 Processing section, 112 Processor, 114 Main memory, 116 Internal interface, 117 General-purpose interface, 118 Network interface, 120 Storage, 122 Operating system, 124 Measurement program, 126 Detection results, 128 Measurement results, 130 Power supply section, 132 Battery, 150 Buffer, 152 Wavenumber conversion section, 154 Fourier transformation section, 156 Peak search section, 158 Film thickness determination unit, 160, measurement reliability calculation unit, 162, output processing unit, 200, 200A, 200B, 200C, 200D, 200E, probe, 202, light emitting / receiving unit, 204, light guide path, 206, 208, terminal mechanism, 224, main body, 226, flexible part, 228, contact part, 230, rubber gasket, 232, spring, 234, 236, plate, 235, first rotation axis, 237, second rotation axis, 238, link member, 240, bellows, 242, ball joint, 1060, display, 1062, measurement value, 1064, status bar, 1066, numerical value, 1068, indicator.

Claims

1. 1. An optical measurement system for measuring the spectral reflectance of a sample, comprising: a light source that generates measurement light; a light receiving unit that receives light generated by irradiating the sample with the measurement light as observation light; a probe optically connected to the light source and the light receiving unit and capable of being placed at an arbitrary position; a calculation processing unit that measures the spectral reflectance of the sample based on the detection result by the light receiving unit and calculates a measurement result based on the measured spectral reflectance, the probe includes a main body portion that is held by a user and a flexible portion that is bendable so that the measurement light is incident perpendicularly on the sample; An optical measurement system, wherein a bendable light guide is disposed within the probe.

2. The optical measurement system of claim 1 , wherein the flexible portion includes a spring coupled to the body portion.

3. 1. An optical measurement system for measuring the spectral reflectance of a sample, comprising: a light source that generates measurement light; a light receiving unit that receives light generated by irradiating the sample with the measurement light as observation light; a probe optically connected to the light source and the light receiving unit and capable of being placed at an arbitrary position; a calculation processing unit that measures the spectral reflectance of the sample based on the detection result by the light receiving unit and calculates a measurement result based on the measured spectral reflectance, the probe includes a main body portion that is held by a user and a flexible portion that is bendable so that the measurement light can be incident perpendicularly on the sample; The optical measurement system, wherein the flexible portion is made of a flexible material.

4. 1. An optical measurement system for measuring the spectral reflectance of a sample, comprising: a light source that generates measurement light; a light receiving unit that receives light generated by irradiating the sample with the measurement light as observation light; a probe optically connected to the light source and the light receiving unit and capable of being placed at an arbitrary position; a calculation processing unit that measures the spectral reflectance of the sample based on the detection result by the light receiving unit and calculates a measurement result based on the measured spectral reflectance, the probe includes a main body portion that is held by a user and a flexible portion that is bendable so that the measurement light can be incident perpendicularly on the sample; An optical measurement system, wherein the flexible portion includes an axis mechanism that can rotate around two axes that are perpendicular to each other, a bellows connected to the main body portion, or a ball joint that is rotatably connected to the main body portion.

5. 5. The optical measurement system according to claim 1, wherein the probe further includes a contact portion provided at the tip of the flexible portion and adapted to come into contact with the sample.

6. A probe constituting an optical measurement system for measuring the spectral reflectance of a sample, the optical measurement system a light source that generates measurement light; a light receiving unit that receives light generated by irradiating the sample with the measurement light as observation light; a calculation processing unit that measures the spectral reflectance of the sample based on the detection result by the light receiving unit and calculates a measurement result based on the measured spectral reflectance, the probe includes a main body portion that is held by a user and a flexible portion that is bendable so that the measurement light is incident perpendicularly on the sample; the probe is optically connected to the light source and the light receiving unit and is configured to be able to be placed at any position; A probe having a bendable light guide disposed inside the probe.

7. A probe as described in claim 6, wherein the flexible portion includes a spring connected to the main body portion.

8. A probe constituting an optical measurement system for measuring the spectral reflectance of a sample, the optical measurement system a light source that generates measurement light; a light receiving unit that receives light generated by irradiating the sample with the measurement light as observation light; a calculation processing unit that measures the spectral reflectance of the sample based on the detection result by the light receiving unit and calculates a measurement result based on the measured spectral reflectance, the probe includes a main body portion that is held by a user and a flexible portion that is bendable so that the measurement light is incident perpendicularly on the sample; the probe is optically connected to the light source and the light receiving unit and is configured to be able to be placed at any position; The probe, wherein the flexible portion is made of a flexible material.

9. A probe constituting an optical measurement system for measuring the spectral reflectance of a sample, the optical measurement system a light source that generates measurement light; a light receiving unit that receives light generated by irradiating the sample with the measurement light as observation light; a calculation processing unit that measures the spectral reflectance of the sample based on the detection result by the light receiving unit and calculates a measurement result based on the measured spectral reflectance, the probe includes a main body portion that is held by a user and a flexible portion that is bendable so that the measurement light is incident perpendicularly on the sample; the probe is optically connected to the light source and the light receiving unit and is configured to be able to be placed at any position; A probe in which the flexible portion includes an axis mechanism that can rotate around two axes that are perpendicular to each other, a bellows connected to the main body portion, or a ball joint that is rotatably connected to the main body portion.

Images