Optical Measurement System

Abstract

To provide an optical measurement system for measuring a film thickness, which is the thickness of a layer in a sample.SOLUTION: An optical measurement system includes: a light source for generating measurement light; a light receiving unit for receiving reflected light or transmitted light as observation light, the reflected light or the transmitted light being generated when the measurement light is irradiated to a sample; a probe optically connected to the light source and the light receiving unit and placeable at an arbitrary position; a film thickness calculation unit for calculating the film thickness of the sample from spectral reflectance or spectral transmittance calculated based on a detection result by the light receiving unit; and a reliability calculation unit (160) for calculating a measurement reliability indicating how appropriately the film thickness calculated by the film thickness calculation unit was measured.SELECTED DRAWING: Figure 35

Description

[Technical Field]

[0001] The present invention relates to a portable optical measurement system, an optical measurement method in the optical measurement system, and a measurement program for implementing the optical measurement method. [Background technology]

[0002] There is a demand for controlling the film thickness of manufactured products, and to meet such 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 the spectral reflectance.

[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 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] 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.

[0010] One object of the present invention is to provide an optical measurement system that can appropriately measure the film thickness of a sample. The purpose is to provide. [Means for solving the problem]

[0011] According to one aspect of the present invention, there is provided an optical measurement system for measuring a film thickness, which is the thickness of a layer contained in a sample. The optical measurement system includes a light source that generates measurement light, a light receiving unit that receives reflected light or transmitted 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 an arbitrary position, a film thickness calculation unit that calculates the film thickness of the sample from the spectral reflectance or spectral transmittance calculated based on the detection result by the light receiving unit, and a reliability calculation unit that calculates a measurement reliability that indicates how accurately the film thickness calculated by the film thickness calculation unit was measured.

[0012] The optical measurement system may further include an output unit that notifies the measurement reliability calculated by the reliability calculation unit.

[0013] The output unit may generate a notification sound corresponding to the level of the measurement reliability.

[0014] The output unit may output at least one of light and an image indicating the measurement reliability.

[0015] The optical measurement system may further include a determination unit that determines the film thickness at the point in time when the measurement reliability satisfies a predetermined condition as the measurement result.

[0016] The film thickness calculation unit may calculate the film thickness of the sample based on peaks appearing in a spectrum calculated by frequency-converting the spectral reflectance or the spectral transmittance. The reliability calculation unit may calculate the measurement reliability based on the magnitudes of the peaks appearing in the spectrum.

[0017] The film thickness calculation unit may calculate the film thickness of the sample by fitting parameters of a model indicating the spectral reflectance or the spectral transmittance so that the parameters match the spectral reflectance or the spectral transmittance calculated based on the observed light. The reliability calculation unit may calculate the measurement reliability based on the fitting result determined by the film thickness calculation unit.

[0018] The probe may be configured to be changeable into different types depending on the sample.

[0019] At least the film thickness calculation unit and the reliability calculation unit may be mounted in a housing independent of the probe.

[0020] At least the probe, the light source, and the light receiving unit may be mounted in a single housing.

[0021] According to another aspect of the present invention, there is provided an optical measurement method for measuring a film thickness, which is the thickness of a layer contained in a sample, comprising the steps of: irradiating the sample with measurement light emitted from a light source through a probe that can be positioned at an arbitrary position; receiving reflected or transmitted light generated by irradiating the sample with the measurement light with a light receiving unit as observation light; calculating the film thickness of the sample from the spectral reflectance or spectral transmittance calculated based on the detection result by the light receiving unit; and calculating a measurement reliability that indicates how accurately the calculated film thickness was measured.

[0022] According to yet another aspect of the present invention, there is provided a measurement program for measuring a film thickness, which is the thickness of a layer contained in a sample. The measurement program causes a computer to receive, via a probe that can be positioned at an arbitrary position, reflected light or transmitted light that is generated when measurement light emitted from a light source is irradiated onto the sample, and calculates a spectral reflectance or a spectral transmittance based on the detection result. The method executes a step of calculating the film thickness of the sample from the transmittance, and a step of calculating the measurement reliability, which indicates how accurately the calculated film thickness has been measured. [Effects of the Invention]

[0023] According to an embodiment of the present invention, the film thickness of a sample can be appropriately measured. [Brief explanation of the drawings]

[0024] [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 the appearance of a probe 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 used in the optical measurement system according to the present embodiment. [Figure 6] FIG. 2 is a schematic diagram showing an example of a pen-type probe used in the optical measurement system according to the present embodiment. [Figure 7] FIG. 10 is a schematic diagram showing an example of an attachment attached to a pen-shaped probe used in the optical measurement system according to the present embodiment. [Figure 8] FIG. 2 is a schematic diagram showing an example of a V-groove type probe used in the optical measurement system according to the present embodiment. [Figure 9] FIG. 2 is a schematic diagram showing an example of an L-shaped probe used in the optical measurement system according to the present embodiment. [Figure 10] FIG. 2 is a schematic diagram showing an example of a non-contact probe used in the optical measurement system according to the present embodiment. [Figure 11] FIG. 2 is a schematic diagram showing an example of a non-contact probe used in the optical measurement system according to the present embodiment. [Figure 12] FIG. 2 is a schematic diagram showing an example of a probe with a movable tip used in the optical measurement system according to the present embodiment. [Figure 13] 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 14] FIG. 2 is a schematic diagram showing an example of a liquid probe used in the optical measurement system according to the present embodiment. [Figure 15] FIG. 2 is a schematic diagram showing an example of a probe for an oil film used in the optical measurement system according to the present embodiment. [Figure 16]FIG. 2 is a schematic diagram showing an example of a multi-angle probe used in the optical measurement system according to the present embodiment. [Figure 17] 1 is a diagram showing an example of a usage form of a measurement device and a probe in an optical measurement system according to the present embodiment. [Figure 18] FIG. 10 is a schematic diagram showing an optical measurement system according to a modified example of the present embodiment. [Figure 19] FIG. 10 is a schematic diagram showing an optical measurement system according to another modified example of the present embodiment. [Figure 20] 1 is a schematic diagram showing an example of a cross-sectional structure of a sample whose film thickness is to be measured by the optical measurement system according to the present embodiment. [Figure 21] 10A and 10B are diagrams for explaining factors that make film thickness measurement unstable in the optical measurement system according to the present embodiment. [Figure 22] 10A and 10B are diagrams for explaining another factor that makes film thickness measurement unstable in the optical measurement system according to the present embodiment. [Figure 23] FIG. 10 is a diagram for explaining yet another factor that makes film thickness measurement unstable in the optical measurement system according to the present embodiment. [Figure 24] 10A and 10B are diagrams for explaining an example of a method for calculating measurement reliability in the optical measurement system according to the present embodiment. [Figure 25] 10A and 10B are diagrams for explaining another example of the method for calculating measurement reliability in the optical measurement system according to the present embodiment. [Figure 26] FIG. 10 is a diagram for explaining yet another example of the method for calculating measurement reliability in the optical measurement system according to the present embodiment. [Figure 27] 22A to 22C are diagrams showing examples of spectral reflectance measured in each state of the probe shown in FIG. 21. [Figure 28] 10A and 10B are diagrams for explaining processing in a search support mode of the optical measurement system according to the present embodiment. [Figure 29] 10 is a flowchart showing a processing procedure in a search support mode of the optical measurement system according to the present embodiment. [Figure 30]This is a diagram for explaining the processing in the automatic measurement mode of the optical measurement system according to this embodiment. [Figure 31] This is a flowchart showing the processing procedure in the automatic measurement mode of the optical measurement system according to this embodiment. [Figure 32] This is a diagram for explaining the processing in the automatic measurement mode with search support of the optical measurement system according to this embodiment. [Figure 33] This is a flowchart showing the processing procedure in the automatic measurement mode with search support of the optical measurement system according to this embodiment. [Figure 34] This is a schematic diagram showing an example of the notification form of the measurement reliability in the optical measurement system according to this embodiment. [Figure 35] This is a schematic diagram showing an example of the functional configuration provided by the optical measurement system according to this embodiment.

Embodiments for Carrying out the Invention

[0025] 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.

[0026] <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 film thickness measurement device that measures the film thickness of a sample using light. More specifically, the optical measurement system 1 is a spectroscopic interference type film thickness measurement device.

[0027] In this specification, "film thickness" means the thickness of a specific layer or film contained in an arbitrary sample. That is, the optical measurement system 1 measures the film thickness, which is the thickness of the layer contained in the sample.

[0028] In the following explanation, we will mainly explain an optical system (reflected light observation system) that irradiates a sample with light and observes the reflected light, but it is also naturally applicable to an optical system (transmitted light observation system) that irradiates a sample with light and observes the transmitted light. Therefore, in the following explanation, unless otherwise specified, the term "reflected light" includes "transmitted light" in addition to the original "reflected light." Similarly, the term "reflectance" includes "transmittance" in addition to the original "reflectance."

[0029] (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.

[0030] In particular, the optical measurement system 1 according to this embodiment is portable and can perform measurements at any position. In the example configuration shown in Fig. 1, a user can hold the measuring device 100 in one hand and the probe 200 in the other hand, and measure any sample at any position. Note that the user does not need to hold the measuring device 100 and / or the probe 200 all the time during measurement. In this way, the probe 200 can be placed at any position.

[0031] 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 .

[0032] 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.

[0033] 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.

[0034] (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).

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] The arithmetic processing unit 110 has a film thickness calculation function, which calculates the film thickness of the sample from the spectral reflectance (or spectral transmittance) calculated based on the detection results (intensity for each wavelength of the observation light 24) by the spectroscopic measurement unit 104. In addition to the film thickness calculation function, 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, which will be described later.

[0043] The algorithm for determining the film thickness of a sample is FFT (Fast Fourier transform). Transform methods and optimization methods can be used.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] The operating system 122 provides an environment in which the processor 112 executes a 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 is output by the spectroscopic measurement unit 104. The measurement results 128 include data on the intensity for each wavelength of the input observation light 24. The measurement results 128 include the measurement results of the film thickness of the sample obtained by executing the measurement program 124.

[0049] The internal interface 116 mediates data transmission between components included in the measurement device 100 .

[0050] The general-purpose interface 117 is, for example, a USB (Universal Serial The general-purpose interface 117 and / or the network interface 118 may be configured with a network bus (LAN) or a network bus (BUS) and mediate data transmission between the general-purpose interface 117 and the network interface 118, for example, a wired LAN or a wireless LAN and mediate data transmission between the general-purpose interface 117 and the network interface 118. The general-purpose interface 117 and / or the network interface 118 may transmit the detection results 126 stored in the storage 120 to another information processing device and receive the measurement results 128 processed by the other information processing device. By providing such an interface with another information processing device, the other information processing device can be responsible for all or part of the necessary analysis processing.

[0051] 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.

[0052] 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.

[0053] 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, a field-programmable gate array (FPGA) or an application specific integrated circuit (ASIC)). In addition to processors such as a CPU or GPU, a DSP (Digital Signal Processor) may also be used. It may also be realized by using an SoC (System on Chip) that integrates a Digital Signal Processor (DSP) and an Image Signal Processor (ISP).

[0054] (a3: Probe 200 configuration example) Fig. 4 is a schematic diagram showing an example of the appearance of probe 200 used in optical measurement system 1 according to this embodiment. Probe 200 shown in Fig. 4 has a light projecting and receiving unit 202 that irradiates measurement light 22 supplied from measurement device 100 and receives observation light 24 generated by the sample. The end face of probe 200 is flat and circular, and light projecting and receiving unit 202 is formed in a recess formed in the center of the circle.

[0055] FIG. 5 is a schematic diagram showing an example of a cross-sectional structure of probe 200 used in optical measurement system 1 according to the present embodiment.

[0056] 5(A), a light guide path 204 optically connected to the optical fiber 20 is formed inside the probe 200. 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.

[0057] 5(A) is in contact with the sample 4, the sample 4 is irradiated with the measurement light 22. The observation light 24 generated by the sample 4 is analyzed by the measurement device 100, and the film thickness of the sample 4 is measured.

[0058] 5(B), a reference cap 30 may be provided to be attached to the probe 200. The reference cap 30 is used for calibrating the optical measurement system 1. The reference cap 30 can also be used to prevent dust and other particles from entering the probe 200 when the probe 200 is stored.

[0059] When the reference cap 30 is attached to the probe 200, a mirror 32 is provided at a position facing the light projecting and receiving unit 202 of the probe 200. The mirror 32 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 30 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.

[0060] As described above, multiple types of probes 200 may be prepared depending on the shape and characteristics of the sample 4. The user optically connects an appropriate probe 200 from the multiple types of probes 200 to the measuring device 100 via the coupler 28 depending on the sample 4. In this way, the probe 200 is configured to be changeable to different types depending on the sample 4.

[0061] 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) curved surface probes, (9) submerged probes, (10) oil film probes, and (11) multi-angle probes.

[0062] (1) The stethoscope-type probe has a shape as shown in FIG. 4 and is suitable for measuring the film thickness of a sample 4 that can be pressed against a measurement surface. For example, it can be used to measure the film thickness of a transparent or translucent planar sample (e.g., food packaging wrap, PET film, glass substrate, planar substrate such as a semiconductor, or a coating layer formed on a planar substrate). Because the stethoscope-type probe has a flat end face, pressing it against the sample 4 makes it easy to achieve a perpendicular light irradiation angle relative to the measurement surface (optical axis adjustment to set the angle of incidence and reflection to 0°). In other words, the measurement light 22 can be irradiated perpendicularly to the measurement surface without the user even realizing it.

[0063] (2) The pen-type probe is primarily used to measure the local film thickness of the sample 4.

[0064] 6 is a schematic diagram showing an example of a pen-shaped probe 200C used in the optical measurement system according to the present embodiment. Referring to FIG. 6, probe 200C measures the film thickness of sample 4, which contains a local three-dimensional structure. By making it similar in shape to a pen, it is possible to improve the user's grip and operability.

[0065] An attachment suitable for the sample 4 may be attached to the tip of the probe 200C.

[0066] FIG. 7 is a schematic diagram showing an example of an attachment attached to a pen-shaped probe 200C used in the optical measurement system according to the present embodiment. FIG. 7(A) shows an example of an attachment 210 that becomes wider towards the tip. By attaching the attachment 210, the sample When the measurement surface of the sample 4 is flat, it becomes easier to press the probe 200C against the sample 4. FIG. 7(B) shows an example of an attachment 212 that becomes thinner towards the tip. By attaching the attachment 212, it becomes easier to press the probe 200C against the sample 4 even when the measurement surface of the sample 4 is narrow. In this way, by providing an attachment that can be attached to the tip of the probe 200C, it is possible to accommodate samples 4 of various shapes.

[0067] (3) The V-groove probe is primarily used to measure the thickness of a coating layer formed on the outside of a cylindrical sample 4 (for example, a catheter, a metal tube, or the like).

[0068] 8 is a schematic diagram showing an example of a V-groove probe 200D used in the optical measurement system according to the present embodiment. Referring to FIG. 8, probe 200D includes a pair of support members 214 that support sample 4. A gap is provided between support members 214, allowing measurement light 22 and observation light 24 to pass through.

[0069] By supporting the sample 4 with the support members 214 of the V-groove type probe 200D, it is possible to easily achieve perpendicularity of the light irradiation angle relative to the measurement region (microsurface) on the curved surface of the sample 4. Note that a mechanism may be employed that can adjust the opening angle of the support members 214 in accordance with the curvature of the sample 4. Specifically, a mechanism may be employed in which a spring or the like is disposed between the support members 214 that form the V-shaped groove, and the opening angle can be adjusted according to the magnitude of the force pressing the sample 4 against the support members 214.

[0070] (4) The L-shaped probe is primarily used to measure the thickness of coating layers formed on the inside of cylindrical samples. The L-shaped probe is bent to allow access even when there is limited space above the sample.

[0071] 9A and 9B are schematic diagrams showing an example of an L-shaped probe used in the optical measurement system according to the present embodiment. Referring to Fig. 9A, an L-shaped probe 200E includes a light guide 204 optically connected to an optical fiber 20 and a mirror 216. Measurement light 22 emitted from light guide 204 has its propagation direction changed by 90° by mirror 216 and is then incident on the measurement surface of sample 4. Similarly, observation light 24 from sample 4 has its propagation direction changed by 90° by mirror 216 and is then guided to light guide 204.

[0072] 9(B) shows a probe 200F in which a support member 218 is provided on the outer periphery of the probe 200E shown in FIG. 9(A). The support member 218 of the probe 200F is selected to match the inner diameter of the sample 4, so that the probe 200F can be easily rotated inside the cylindrical sample 4. This makes it possible to measure the film thickness of the coating layer formed inside the sample 4 over the entire circumference.

[0073] (5) The mini-spot probe is primarily used with a stethoscope-type probe to measure the film thickness of samples with rough surfaces, uneven surfaces, or light-diffusing surfaces. The mini-spot probe reduces the noise components contained in the observation light 24 because the irradiation area (light-receiving area) of the measurement light 22 is a minute spot.

[0074] (6) The non-contact probe has an optical system designed to enable measurement even when the distance from the measurement position on the sample to the probe is relatively long, making it possible to measure without directly contacting the sample.

[0075] 10 is a schematic diagram showing an example of a non-contact type probe 200G used in the optical measurement system according to the present embodiment. Referring to FIG. 10, the probe 200G includes a lens 220 and a lens 222, and focuses the measurement light 22 irradiated from the light guide 204 onto the sample 4. Similarly, lenses 220 and 222 guide observation light 24 from sample 4 to light guide path 204. By employing such an optical system, the film thickness of sample 4 can be measured without directly contacting probe 200G with sample 4.

[0076] Since the non-contact probe is held by the user, the measurement mode (described later) provided by the optical measurement system 1 is more effective.

[0077] Although FIG. 10 shows an example of a configuration in which the focal position is fixed, the focal position may be variable.

[0078] 11 is a schematic diagram showing an example of a non-contact type probe 200H used in the optical measurement system according to the present embodiment. With reference to FIGS. 11(A) and 11(B), in probe 200H, lens 222 is configured so that its position in the optical axis direction can be changed. By moving lens 222 away from lens 220, the focal position becomes longer (see FIG. 11(A)), and by moving lens 222 closer to lens 220, the focal position becomes shorter (see FIG. 11(B)).

[0079] (7) A tip-moving probe is used, for example, to measure the thickness of a film inside a structure with a narrow entrance or a film thickness of a sample with a curved access path.

[0080] 12 is a schematic diagram showing an example of a tip-movable probe 200I used in the optical measurement system according to the present embodiment. Referring to FIG. 12, the tip of probe 200I is provided with a mirror (not shown) that changes the propagation direction of measurement light 22 and observation light 24, similar to the L-shaped probe shown in FIG. 9. As shown in FIGS. 12(A) and 12(B), the tip of probe 200I is structured so that the tip can be freely bent by user manipulation. This is effective in cases where the user cannot directly press the probe against something.

[0081] (8) A curved surface probe is primarily used to measure the film thickness of a sample whose measurement position is curved.

[0082] 13 is a schematic diagram showing an example of probe 200J for curved surfaces used in the optical measurement system according to the present embodiment. Referring to FIG. 13, probe 200J has a bendable flexible section 226 at its tip. Flexible section 226 is made of a soft material. A user can press probe 200J against any measurement position on sample 4 to 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).

[0083] 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.

[0084] (9) Liquid probes are primarily used to measure the film thickness of a sample present in a liquid.

[0085] Fig. 14 is a schematic diagram showing an example of a probe 200K for liquids used in the optical measurement system according to the present embodiment. Referring to Fig. 14, probe 200K has, as an example, a configuration similar to that of a stethoscope-type probe, but each part is sealed so that it can be used in liquids.

[0086] (10) The oil film probe has a needle-shaped part at the tip of the probe that comes into contact with the measurement position, making it easy to measure the thickness of liquid films, including oil films.

[0087] Fig. 15 is a schematic diagram showing an example of a probe 200L for an oil film used in the optical measurement system according to the present embodiment. Referring to Fig. 15, the probe 200L has, as an example, a configuration similar to that of a stethoscope-type probe, but is provided with a needle portion 234 so as to reduce the effect on the oil film.

[0088] (11) The multi-angle probe employs a configuration that allows the incident angle of the measurement light 22 on the sample 4 to be varied.

[0089] 16 is a schematic diagram showing an example of a multi-angle probe 200M used in the optical measurement system according to the present embodiment. Referring to FIG. 16, probe 200M is configured to allow measurement light 22 to be incident at an angle that is not perpendicular to the measurement surface of sample 4. Furthermore, since observation light 24 from sample 4 also propagates at an angle that is not perpendicular to the measurement surface of sample 4, probe 200M is configured to be able to receive such observation light 24.

[0090] Although the above-mentioned Figures 1 and 2 show an example of a configuration in which the measuring device 100 and the probe 200 are separate entities, 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.

[0091] FIG. 17 shows an example of how to use measuring device 100 and probe 200 in the optical measurement system according to the present embodiment.

[0092] 17(A) shows an example of a configuration in which the measurement device 100 and the probe 200 are connected and integrated together. By configuring the probe 200 to irradiate the measurement light 22 upward, a tabletop optical measurement system suitable for measuring the film thickness of a sample 4 such as a film can be realized.

[0093] 17(B) shows an example of a configuration in which the measurement device 100 and the probe 200 are integrated together. By adopting such an integrated configuration, the overall configuration of the optical measurement system can be simplified.

[0094] (a4: Variation 1: Integrated type) Fig. 18 is a schematic diagram showing an optical measurement system 1A according to a modification of the present embodiment. Referring to Fig. 18, optical measurement system 1A includes measuring device 100A that packages the functions of measuring device 100 and probe 200 shown in Figs. 1 and 2.

[0095] More specifically, the measurement device 100A 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, a power supply unit 130, and a probe 200. The probe 200 is disposed in a portion exposed from the housing of the measurement device 100A so that it can come into contact with the sample. Thus, in the configuration example shown in Fig. 18, the probe 200, the light source 102, and the spectroscopic measurement unit 104 are mounted in a single housing.

[0096] 18 have substantially the same functions as the components with the same reference numerals shown in Fig. 2, and therefore will not be described in detail here. However, light source 102 is optically connected to probe 200 via optical fiber 52 arranged within the housing of measurement device 100A, and spectroscopic measurement unit 104 is optically connected to probe 200 via optical fiber 54 arranged within the housing of measurement device 100A.

[0097] (a5: Variation 2: Wireless connection configuration) 1 and 2 show an example of a configuration in which the measuring device 100 and the probe 200 are optically connected, but the measuring device 100 and the probe 200 may be connected wirelessly.

[0098] Fig. 19 is a schematic diagram showing an optical measurement system 1B according to another modification of the present embodiment. Referring to Fig. 19, the optical measurement system 1B includes a measurement device 100B and an advanced probe 200B.

[0099] Typical components of measuring device 100B include output section 106, operation section 108, calculation processing section 110, power supply section 130, and communication section 134. The components included in measuring device 100B are packaged and housed in a housing.

[0100] In addition to the probe 200, the advanced probe 200B includes a light source 102, a spectroscopic measurement unit 104, a power supply unit 130, and a communication processing unit 136. The components included in the advanced probe 200B are packaged and housed in a housing. Thus, in the configuration example shown in Fig. 19, the probe 200, the light source 102, and the spectroscopic measurement unit 104 are mounted in a single housing.

[0101] The communication unit 134 of the measurement device 100B and the communication processing unit 136 of the advanced probe 200B exchange the detection results (intensity of each wavelength of the observation light 24) by the spectroscopic measurement unit 104 via wireless communication. Any method can be used for wireless communication, such as wireless LAN, Bluetooth (registered trademark), infrared communication, or a public wireless line such as 4G or 5G.

[0102] The communication processing unit 136 performs various processes in the highly functional probe 200B and also wirelessly transmits the detection results of the spectroscopic measurement unit 104. The communication unit 134 outputs the detection results of the spectroscopic measurement unit 104 wirelessly transmitted by the communication processing unit 136 to the arithmetic processing unit 110.

[0103] Since each of the other components shown in FIG. 19 has substantially the same function as the components with the same reference numerals shown in FIG. 2, detailed description thereof will not be given here.

[0104] The operating state of the highly functional probe 200B may be controlled by a command from the measuring device 100B. For example, in response to a command from the measuring device 100B, irradiation of the measurement light 22 from the light source 102 of the highly functional probe 200B may be enabled / disabled, or wireless transmission of the communication processing unit 136 of the highly functional probe 200B may be enabled / disabled.

[0105] When using the highly functional probe 200B, it may be operated by power supply from the battery 132 of the power supply unit 130 instead of power supply from an external power source.

[0106] (a6: Implementation method) The measurement devices 100, 100A, and 100B described above may be implemented using a small personal computer. In this case, many components included in the measurement devices 100, 100A, and 100B will be included in the personal computer. Alternatively, the measurement devices 100, 100A, and 100B described above may be implemented using a smartphone, a tablet, or the like.

[0107] 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 technologies available in each era.

[0108] <B. Example of film thickness measurement process> Next, an example of the film thickness measurement process by the optical measurement system 1 according to the present embodiment will be described.

[0109] FIG. 20 is a schematic diagram showing an example of the cross-sectional structure of the sample 4 to be measured for film thickness by the optical measurement system 1 according to the present embodiment. For convenience of explanation, FIG. 20 shows a sample 4 in which a coating layer 41 is formed on a substrate layer 42. It is assumed that the coating layer 41 is in contact with the air layer 40.

[0110] Referring to FIG. 20, we consider the reflected light that occurs when the measurement light 22 irradiated from the probe 200 is reflected at the interface between the coating layer 41 and the substrate layer 42. In the following explanation, each layer is represented by a subscript i. That is, the air layer 40 is represented by a subscript "0", the coating layer 41 of the sample is represented by a subscript "1", and the substrate layer 42 is represented by a subscript "2". The refractive index of each layer is represented by a subscript i, and the refractive index n i It is expressed as:

[0111] Different refractive indices n i Since light is reflected at the interface of layers with different refractive indices, the amplitude reflectance (Fresnel coefficient)r (P) i,i+1 ,r (S) i,i+1 can be expressed as follows:

[0112]

number

[0113] where φ i is the angle of incidence at the i-th layer. This angle of incidence φ i is similar to Snell's By law, it can be calculated from the angle of incidence of the measuring light 22 on the top air layer 40 .

[0114] 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:

[0115]

number

[0116] where d i denotes the thickness of the i-layer, and λ denotes the wavelength of the incident light.

[0117] 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:

[0118]

number

[0119] Furthermore, the reflectance R for sample 4 shown in FIG. 20 is as follows:

[0120]

number

[0121] 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.

[0122]

number

[0123] 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 Rb 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.

[0124] Therefore, the wave number K1 in the target coating layer 41 can be defined as follows:

[0125]

number

[0126] Here, the propagation characteristics of the electromagnetic wave in the coating layer 41 depend on the wave number K1. That is, It can be seen that the speed of light with wavelength λ in a vacuum decreases within the layer, and therefore the wavelength also increases from λ to λ / n1. Taking into account this wavelength dispersion phenomenon, the wavenumber transformation reflectance R' is defined as follows:

[0127]

number

[0128] 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.

[0129] 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 performing frequency conversion on the 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 value 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.

[0130] As a method for analyzing the wavenumber component with a large amplitude value from the wavenumber distribution characteristics, an FFT method using a discrete Fourier transform such as FFT or a method using an optimization method such as the Maximum Entropy Method can be adopted.

[0131] <C. Measurement reliability> Next, the measurement reliability provided by the optical measurement system 1 according to the present embodiment will be described.

[0132] The optical measurement system 1 according to the present embodiment is configured as a portable type that can be held by a user and measured at an arbitrary position. Further, in the spectroscopic interference method using the reflected light observation system adopted by the optical measurement system 1, it is necessary to receive the observation light 24 that can be generated by the sample 4 with the probe 200 for the measurement light 22 irradiated from the probe 200. Therefore, depending on the state in which the user holds it, the measurement may become unstable. Hereinafter, some factors that make the film thickness measurement unstable will be described.

[0133] FIG. 21 is a diagram for explaining the factors that make the film thickness measurement in the optical measurement system 1 according to the present embodiment unstable. FIG. 21 shows an example in which the incident angle of the measurement light 22 with respect to the measurement surface of the sample 4 becomes inappropriate.

[0134] 21, when the probe 200 is positioned directly opposite the measurement surface of the sample 4, the measurement light 22 emitted from the probe 200 generates an observation light 24 which is incident on the probe 200. As shown in FIG.

[0135] However, if the probe 200 is tilted with respect to the measurement surface of the sample 4 , the observation light 24 generated by the measurement light 22 irradiated from the probe 200 cannot be properly incident on the probe 200 .

[0136] In particular, when using a non-contact probe or a probe for curved surfaces, the user must hold the probe 200 during measurement, which can make the measurement unstable as it is difficult to maintain an appropriate angle of incidence of the measurement light 22 with respect to the measurement surface of the sample 4.

[0137] Similarly, if the surface of the sample 4 is curved or has a complex shape, it is difficult to maintain an appropriate angle of incidence of the measurement light 22 with respect to the measurement surface of the sample 4, which can make the measurement unstable.

[0138] Fig. 22 is a diagram for explaining another factor that can cause instability in film thickness measurement in optical measurement system 1 according to the present embodiment. Fig. 22 shows an example in which measurement light 22 is improperly focused on the measurement surface of sample 4.

[0139] Referring to Figure 22, when the distance between the probe 200 and the measurement surface of the sample 4 is appropriate, the measurement light 22 irradiated from the probe 200 is focused on the measurement surface of the sample 4, and appropriate observation light 24 is generated from the sample 4 and enters the probe 200.

[0140] However, if the distance between the probe 200 and the measurement surface of the sample 4 is too far or too close, the measurement light 22 emitted from the probe 200 will be focused at a position away from the measurement surface of the sample 4, and will not produce appropriate observation light 24.

[0141] In particular, when using a non-contact probe or a probe for curved surfaces, the user must hold the probe 200 during measurement, which can make it difficult to maintain an appropriate distance between the probe 200 and the measurement surface of the sample 4, which can result in unstable measurements.

[0142] Similarly, if the surface of the sample 4 is curved or has a complex shape, it is difficult to maintain an appropriate distance between the probe 200 and the measurement surface of the sample 4, which can make the measurement unstable.

[0143] 23 is a diagram for explaining yet another factor that makes film thickness measurement unstable in optical measurement system 1 according to the present embodiment. FIG. 23 shows an example caused by the microstructure of sample 4.

[0144] 23, when a sample 4 is assumed to have a coating layer 41 formed on a substrate layer 42, fine irregularities may exist in the coating layer 41. Alternatively, fine irregularities may exist on the surface of the coating layer 41. Furthermore, a sample 4 may have a structure in which only a portion of the sample 4 has a measurable structure.

[0145] Since the observation light 24 that may be generated in the sample 4 needs to be received by the probe 200, in such a sample 4, the film thickness may not be measured properly depending on the measurement position.

[0146] 23, when the measurement surface of sample 4 is substantially parallel to the end face of probe 200, observation light 24 generated by measurement light 22 irradiated from probe 200 is incident on probe 200.

[0147] However, if the measurement surface of the sample 4 is significantly tilted from the end face of the probe 200 , the observation light 24 generated by the measurement light 22 irradiated from the probe 200 cannot be properly incident on the probe 200 .

[0148] Therefore, in order to prevent a film thickness measured in an unstable state as described above from being output, the optical measurement system 1 calculates the measurement reliability of the film thickness measurement.

[0149] In this specification, "measurement reliability" refers to the degree to which a measured or calculated measurement result (for example, film thickness) is accurately measured.

[0150] Any method can be used to calculate the measurement reliability, but several calculation methods will be described as typical examples.

[0151] (c1: Calculation method of measurement reliability using FFT method) First, a method suitable for calculating the film thickness using the FFT method will be described.

[0152] Fig. 24 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. 24 shows a method for calculating measurement reliability when calculating the film thickness of a sample using the FFT method.

[0153] Referring to FIG. 24, the spectral reflectance is calculated from the observation light 24 measured from the sample 4, and converted into the wave number transformed reflectance R′ as described above. Then, a frequency transform (Fourier transform) is performed on the wave number 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.

[0154] 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.

[0155] 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.

[0156] 24, 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:

[0157] Measurement reliability = peak area / noise area Alternatively, any of the following formulas may be used:

[0158] 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.

[0159] 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.

[0160] (c2: Calculation method of measurement reliability using optimization method) Next, a method suitable for calculating the film thickness by the optimization method will be described.

[0161] 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).

[0162] In this way, the optimization method calculates the film thickness of the sample by fitting the parameters of the model that indicates the spectral reflectance or spectral transmittance so that they match the spectral reflectance or spectral transmittance calculated based on the observed light 24.

[0163] 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).

[0164] 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.

[0165] 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.

[0166] 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.

[0167] (c3: Calculation method of measurement reliability based on reflectance) FIG. 25 is a diagram for explaining another example of a method for calculating measurement reliability in optical measurement system 1 according to the present embodiment.

[0168] FIG. 25(A) shows an example of spectral reflectance when measurement conditions are poor, and FIG. 25(B) shows an example of spectral reflectance when measurement conditions are appropriate. As shown in FIG. 25, when measurement conditions are appropriate, the amplitude of the spectral reflectance (the difference between the maximum and minimum reflectance values) is relatively large. Therefore, 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 30 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.

[0169] 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.

[0170] 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).

[0171] 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.

[0172] 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.

[0173] 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 minute film thickness distribution on the sample surface, the calculated reflectance (amplitude reflectance) will vary greatly, which means that the measurement reliability is low.

[0174] FIG. 26 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.

[0175] Fig. 26(A) shows an example of reflectance when measurement is unstable, and Fig. 26(B) shows an example of reflectance when measurement is stable. As shown in Fig. 26, 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.

[0176] 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.

[0177] 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.

[0178] (c4: Calculation method of 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 reference cap 30 attached to the probe 200.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] (c5: Calculation method of 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.

[0183] 26(A) and 26(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.

[0184] 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.

[0185] 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.

[0186] (c6: 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.

[0187] Alternatively, for a plurality of measurement reliabilities of an object, they may be multiplied by corresponding weight coefficients respectively to calculate the final measurement reliability. Further alternatively, the weight coefficients may be changed according to conditions.

[0188] In this way, by using multiple types of measurement reliabilities to determine the final measurement reliability, the accuracy of the measurement reliability can be improved.

[0189] <D. Measurement mode of film thickness> In the optical measurement system 1 according to the present embodiment, the following measurement modes may be implemented by using the measurement reliability as described above.

[0190] (d1: Search support mode) The search support mode is a measurement mode that calculates the measurement reliability in real time and notifies the user of the calculated measurement reliability, making it easier for the user to find an appropriate measurement state.

[0191] FIG. 27 is a diagram showing an example of the spectral reflectance measured in each state of the probe 200 shown in FIG. 21. In the states where the film thickness measurement shown in FIGS. 27(A) and 27(C) is unstable, the amplitude of the measured spectral reflectance also becomes small. On the other hand, in an appropriate measurement state as shown in FIG. 27(B), the amplitude of the measured spectral reflectance also becomes large.

[0192] The user changes the angle, distance, and position (measurement position) of the probe 200 with respect to the measurement surface of the sample 4 in a state where the measurement light 22 is irradiated from the probe 200. The measurement device 100 repeatedly calculates the spectral reflectance from the observation light 24 generated in the sample 4 and calculates the film thickness of the sample 4 through processes such as Fourier transform. At the same time, the measurement device 100 also calculates the measurement reliability. Further, the measurement device 100 sequentially notifies the user of the calculated measurement reliability.

[0193] 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:

[0194] 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.

[0195] The user may operate the operation unit 108 (for example, a trigger switch) when the user determines that the measurement state is appropriate. The measurement device 100 outputs or stores the film thickness at the time when the user operates the operation unit 108 as an appropriate measurement result.

[0196] 28 is a diagram illustrating processing in the search support mode of optical measurement system 1 according to the present embodiment. Referring to FIG. 28, the user adjusts the angle, distance, and position (measurement position) while holding probe 200, while checking the measurement reliability using notification sound 38. At this time, measurement light 22 is emitted continuously or intermittently from probe 200. The user then maintains probe 200 in a state where the user determines that the measurement reliability is sufficiently high, and measures the film thickness of sample 4.

[0197] By using the measurement modes described above, the user can measure the film thickness of the sample 4 under appropriate measurement conditions.

[0198] Fig. 29 is a flowchart showing a processing procedure in the search support mode of optical measurement system 1 according to the present embodiment. Each step shown in Fig. 29 is typically realized by processor 112 of arithmetic processing unit 110 of measurement device 100 executing measurement program 124.

[0199] 29, 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 positioned at any position.

[0200] 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.

[0201] 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).

[0202] 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.

[0203] 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.

[0204] By using the above-described search support mode, the user can search for an appropriate measurement state.

[0205] (d2: Automatic measurement mode) The automatic measurement mode is a measurement mode in which measurement results with high measurement reliability are automatically extracted from the start to the end of measurement.

[0206] While the measurement light 22 is being emitted from the probe 200, the user changes the angle, distance, and position (measurement position) of the probe 200 relative to the measurement surface of the sample 4. The measurement device 100 calculates the spectral reflectance from the observation light 24 generated by the sample 4, and repeats the process of calculating the film thickness of the sample 4 through a Fourier transform or the like. At the same time, the measurement device 100 also calculates the measurement reliability corresponding to each film thickness.

[0207] When a series of film thickness measurements is completed, the measurement apparatus 100 determines the calculated film thickness with the highest corresponding measurement reliability as the measurement result.

[0208] 30 is a diagram for explaining the processing in the automatic measurement mode of optical measurement system 1 according to the present embodiment. Referring to FIG. 30, measurement device 100 calculates the film thickness of sample 4 and the corresponding measurement reliability from the start to the end of measurement, and extracts one or more measurement reliabilities that satisfy a predetermined condition (e.g., high measurement reliability) from the calculated measurement reliabilities. Measurement device 100 determines the film thickness corresponding to the extracted one or more measurement reliabilities as the measurement result.

[0209] As shown in Fig. 30, the maximum value of the measurement reliability calculated from the start to the end of the measurement (i.e., one measurement reliability) may be extracted, or one or more measurement reliability values ​​exceeding a predetermined threshold value may be extracted. Furthermore, even when the maximum value of the measurement reliability is extracted, an additional condition may be that the maximum value of the measurement reliability exceeds a predetermined threshold value.

[0210] In this way, any method may be used to extract the measurement reliability.

[0211] Fig. 31 is a flowchart showing the processing procedure in the automatic measurement mode of optical measurement system 1 according to the present embodiment. Each step shown in Fig. 31 is typically realized by processor 112 of arithmetic processing unit 110 of measurement device 100 executing measurement program 124.

[0212] 31, when an instruction to start measurement is given (YES in step S200), 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 S202). 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.

[0213] 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 S204). 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 with 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.

[0214] Furthermore, the measuring apparatus 100 calculates the measurement reliability based on the data used in the process of calculating the film thickness of the sample 4 (step S206). In this way, the measuring apparatus 100 calculates the measurement reliability, which indicates how accurately the calculated film thickness was measured.

[0215] If the measurement end is instructed (YES in step S208), measurement apparatus 100 executes the processes in step S210 and thereafter, and if not (NO in step S208), it repeats the processes in step S204 and thereafter.

[0216] In step S208, the measuring apparatus 100 extracts one or more measurement reliabilities that satisfy a predetermined condition from the measurement reliabilities calculated from the start to the end of the measurement (step S210). Then, the measuring apparatus 100 outputs the film thicknesses corresponding to the extracted one or more measurement reliabilities as measurement results (step S212). Then, the process ends.

[0217] By using the automatic measurement mode as described above, the user can measure the film thickness under appropriate measurement conditions without having to worry about the reliability of the measurement.

[0218] (d3: Automatic measurement mode with search assistance) The search-assisted automatic measurement mode is a measurement mode that automatically extracts measurement results with high measurement reliability from the start to the end of measurement while notifying the user of improvements in measurement reliability.

[0219] While the measurement light 22 is being emitted from the probe 200, the user changes the angle, distance, and position (measurement position) of the probe 200 relative to the measurement surface of the sample 4. The measurement device 100 calculates the spectral reflectance from the observation light 24 generated by the sample 4, and repeats the process of calculating the film thickness of the sample 4 through a Fourier transform or the like. The measurement device 100 also calculates the measurement reliability corresponding to each film thickness. Furthermore, the measurement device 100 sequentially notifies the user whether the calculated measurement reliability is improving.

[0220] Any method may be used to notify the user whether the measurement reliability is improving, but a notification sound indicating the level of measurement reliability may be used so that the user can easily recognize the improvement in measurement reliability while holding the probe 200 and scanning. For example, the notification sound may be generated only when the measurement reliability has changed in a direction higher than the previous measurement reliability. Furthermore, the notification sound to be generated may also correspond to the calculated level of measurement reliability.

[0221] Alternatively, by emitting a notification sound when the measurement reliability improves and a different notification sound when the measurement reliability decreases, the user can easily recognize whether the measurement reliability is improving through their own adjustments.

[0222] When a series of film thickness measurements is completed, the measurement apparatus 100 determines the calculated film thickness with the highest corresponding measurement reliability as the measurement result.

[0223] 32 is a diagram for explaining the processing in the search-assisted automatic measurement mode of optical measurement system 1 according to the present embodiment. Referring to FIG. 32, measurement device 100 calculates the film thickness of sample 4 and the corresponding measurement reliability from the start to the end of measurement, and notifies the user when the calculated measurement reliability has improved.

[0224] When a series of film thickness measurements is completed, the measurement apparatus 100 extracts one or more measurement reliabilities from the calculated measurement reliabilities that satisfy a predetermined condition (e.g., high measurement reliability). The measurement apparatus 100 determines the film thickness corresponding to the determined one or more measurement reliabilities as the measurement result.

[0225] As shown in Fig. 32, a peak that appears in the measurement reliability calculated from the start to the end of the measurement may be extracted, or one or more measurement reliabilities that exceed a predetermined threshold may be extracted. Even when a peak that appears in the measurement reliability is extracted, the peak An additional condition may be that the value of the check exceeds a predetermined threshold.

[0226] In this way, any method may be used to extract the measurement reliability.

[0227] Fig. 33 is a flowchart showing the processing procedure in the search-assisted automatic measurement mode of optical measurement system 1 according to the present embodiment. Each step shown in Fig. 33 is typically realized by processor 112 of arithmetic processing unit 110 of measurement device 100 executing measurement program 124.

[0228] 33, when an instruction to start measurement is given (YES in step S300), 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 S302). 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 positioned at any position.

[0229] 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 S304). 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 with 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.

[0230] Furthermore, the measuring apparatus 100 calculates the measurement reliability based on the data used in the process of calculating the film thickness of the sample 4 (step S306). In this way, the measuring apparatus 100 calculates the measurement reliability, which indicates how accurately the calculated film thickness was measured.

[0231] If the calculated measurement reliability is improving (YES in step S308), the measurement device 100 generates a notification sound indicating that the measurement reliability is improving (step S310). If the calculated measurement reliability is not improving (NO in step S308), the processing of step S310 may be skipped.

[0232] If the measurement end is instructed (YES in step S312), measurement apparatus 100 executes the processes in step S314 and thereafter, and if not (NO in step S312), it repeats the processes in step S304 and thereafter.

[0233] In step S310, the measurement apparatus 100 extracts one or more measurement reliabilities that satisfy a predetermined condition from the measurement reliabilities calculated from the start to the end of the measurement (step S314). Then, the measurement apparatus 100 outputs the film thicknesses corresponding to the extracted one or more measurement reliabilities as measurement results (step S316). Then, the process ends.

[0234] By using the above-described search-assisted automatic measurement mode, the user can search for an appropriate measurement state.

[0235] (d4: Notification method) 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.

[0236] When the measurement reliability is notified by sound (i.e., when the user recognizes the measurement reliability by hearing), one or more of the volume, pitch, and tone may be changed depending on the calculated level of the measurement reliability. The user can change any of the volume, pitch, and tone of the notification sound. By doing so, changes in measurement reliability can be easily recognized.

[0237] Furthermore, notifications are not limited to sound notifications, but can also be made using vibrations, light, images, and the like.

[0238] 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.

[0239] 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.

[0240] Fig. 34 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. 34(A) to Fig. 34(C) show an example of a notification form when display 1060 is used as output unit 106 of measurement device 100.

[0241] 34(A) displays a film thickness measurement value 1062 and a status bar 1064 indicating the measurement reliability on the display 1060 of the measuring 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.

[0242] 34(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.

[0243] On the display 1060 of the measuring device 100 shown in FIG. 34(C), the measured film thickness value 1062 is displayed, and the measuring device 100 is provided with an indicator 1068 indicating the measurement reliability. The indicator 1068 lights up by a number corresponding to the calculated height of the measurement reliability. The user can obtain the measured film thickness value 1062 while recognizing the measurement reliability by checking the indicator 1068 indicating the measurement reliability.

[0244] Not limited to the notification forms shown in FIGS. 34(A) to 34(C), the measurement reliability can be notified to the user in any form.

[0245] <E. Functional Block Diagram> FIG. 35 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. 35 is typically realized by the processor 112 of the arithmetic processing unit 110 of the measuring device 100 executing the measurement program 124.

[0246] Referring to FIG. 35, the measuring 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.

[0247] The buffer 150 stores the detection result (intensity for each wavelength of the observation light 24) from the spectroscopic measurement unit 104.

[0248] 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.

[0249] The Fourier transform unit 154 Fourier-transforms the wave number conversion reflectance calculated by the wave number conversion unit 152.

[0250] The peak search unit 156 searches for peaks included in the power spectrum calculated by the Fourier transform performed 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 result by the spectroscopic measurement unit 104.

[0251] 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 performed by the Fourier transform unit 154.

[0252] When a predetermined condition is satisfied, the film thickness determination unit 158 determines the film thickness output from the peak search unit 156 as the 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.

[0253] The output processing unit 162 is in charge of the process of outputting 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, etc. from the output unit 106. The output processing unit 162 notifies the user of the measurement reliability calculated by the measurement reliability calculation unit 160 through the output unit 106.

[0254] Note that FIG. 35 shows a configuration example in the case of calculating the film thickness by the FFT method as a typical example. However, 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.

[0255] <F. Modified Example> In the above description, an example of a configuration in which the measuring device 100 of the optical measurement system 1 executes the necessary processing has been described, but the present invention is not limited to this, and for example, the processing may be shared among a plurality of processing devices, or part of the processing may be handled by the probe 200. Furthermore, a computing resource (so-called cloud) on a network (not shown) may be responsible for all or part of the necessary processing.

[0256] When a large amount of computing resources are available, machine learning may be performed using measurement results obtained in the past and / or measurement results obtained by other optical measurement systems 1, and the trained model obtained by machine learning may be used to notify the user of the optimal conditions for film thickness measurement.

[0257] <G.まとめ> In the optical measurement system according to this embodiment, a probe that can be placed at an arbitrary position is provided. Since the film thickness of the sample is optically calculated based on the observation light acquired through the optical fiber, the film thickness measurement accuracy can be improved.

[0258] Furthermore, in the optical measurement system according to the present embodiment, the measurement reliability, which indicates how accurately the calculated film thickness was measured, is also calculated, so that the film thickness of the sample can be measured more accurately.

[0259] Furthermore, the optical measurement system according to this embodiment can measure any sample by placing a probe that can be placed at any position, so film thickness can be easily measured at production sites, production lines, etc. Furthermore, even samples with curved surfaces or complex shapes can be easily measured.

[0260] 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]

[0261] 1,1A,1B Optical measurement system, 4 Sample, 10,20,52,54 Optical fiber, 12,14 Branch fiber, 16 Branching section, 22 Measurement light, 24 Observation light, 28 Coupler, 30 Reference cap, 32,216 Mirror, 38 Notification sound, 40 Air layer, 41 Coating layer, 42 Substrate layer, 100, 100A, 100B Measuring device, 102 Light source, 104 Spectroscopic measurement unit, 106 Output unit, 108 Operation unit, 110 Processing unit, 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 unit, 132 Battery, 134 Communication unit, 136 Communication processing unit, 150 Buffer, 152 Wavenumber conversion unit, 154 Fourier transformation unit, 156 Peak search unit, 158 Film thickness determination unit, 160 Measurement reliability calculation unit, 162 Output processing unit, 200, 200C, 200D, 200E, 200F, 200G, 200H, 200I, 200J, 200K, 200L, 200M probe, 200B high-function probe, 202 light-emitting and receiving unit, 204 light guide path, 210, 212 attachment, 214, 218 support member, 220, 222 lens, 226 flexible part, 228 contact part, 230 rubber packing, 234 needle part, 1060 display, 1062 measurement value, 1064 status bar, 1066 numerical value, 1068 indicator.

Claims

1. 1. An optical measurement system comprising: a measurement device including a light source, the measurement device being holdable in one hand of a user; a probe that can be placed at any position while being held by the other hand of the user; an optical fiber that optically connects the measuring device and the probe; the probe is configured to irradiate a sample with light generated by the light source as measurement light, and return reflected light generated by the sample to the measurement device as observation light; the measuring device is configured to calculate a film thickness, which is a thickness of a layer included in the sample, based on the observed light, and display the calculated film thickness; An optical measurement system, wherein the probe is interchangeable depending on the sample.

2. 2. The optical measurement system according to claim 1, wherein the probe has a flat end surface that contacts the sample, and a light projecting and receiving unit that is irradiated with the measurement light and receives the reflected light is provided at the center of the end surface.

3. 2. The optical measurement system according to claim 1, wherein the probe includes a support member for supporting the sample, and a light guide path for irradiating the measurement light onto the sample supported by the support member and receiving the reflected light.

4. 4. The optical measurement system according to claim 1, wherein the optical fiber includes a coupler configured to allow the probe to be detachably attached.

5. the measuring device calculates the film thickness and calculates a measurement reliability indicating how accurately the calculated film thickness was measured; 4. The optical measurement system according to claim 1, wherein a first object indicating the calculated film thickness and a second object indicating the calculated measurement reliability are displayed on a display unit of the measurement device.

6. The optical measurement system according to claim 5 , wherein the display unit is provided at a position visible to the user while the user is holding the measurement device.

7. the measuring device calculates the film thickness and calculates a measurement reliability indicating how accurately the calculated film thickness was measured; 4. The optical measurement system according to claim 1, wherein the measurement device notifies the user of information indicating the calculated measurement reliability by voice or vibration.

8. the measurement device includes a spectroscopic measurement unit that outputs an intensity of light for each wavelength, 4. The optical measurement system according to claim 1, wherein the measurement device calculates the film thickness based on the intensity of the observation light for each wavelength output by the spectroscopic measurement unit.

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