TW202033929A - Optical measuring system and optical measuring method that includes a light source generating measurement light, a spectroscopic detector that detects reflected light and transmitted light of the measurement light, and a processing device calculating optical characteristics - Google Patents

Optical measuring system and optical measuring method that includes a light source generating measurement light, a spectroscopic detector that detects reflected light and transmitted light of the measurement light, and a processing device calculating optical characteristics Download PDF

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TW202033929A
TW202033929A TW109102449A TW109102449A TW202033929A TW 202033929 A TW202033929 A TW 202033929A TW 109102449 A TW109102449 A TW 109102449A TW 109102449 A TW109102449 A TW 109102449A TW 202033929 A TW202033929 A TW 202033929A
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岡本宗大
稲野大輔
森本晃一
田口都一
亀本智彦
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日商大塚電子股份有限公司
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
    • G01B11/0616—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating
    • G01B11/0625—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating with measurement of absorption or reflection
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/28—Investigating the spectrum
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
    • G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/4788—Diffraction
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/59—Transmissivity
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
    • G01N2021/4126—Index of thin films
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N2021/4735—Solid samples, e.g. paper, glass

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Abstract

The present invention is structured to realize measurement of optical characteristics with higher accuracy for a sample of which the measurement accuracy may be lowered with an existing optical measuring device. An optical measuring system of the present invention comprises: a light source, which generates the measurement light irradiating a sample; a spectroscopic detector, which detects the reflected light or transmitted light of the sample generated by the measurement light; and a processing device, which is inputted with the detection result of the spectroscopic detector. The processing device is structured to perform: processing for calculating a first spectrum according to the detection result of the spectroscopic detector; the processing of specifying a section of the first spectrum of which a variation of amplitude with respect to wavelength meets a preset condition; and the processing of calculating the optical characteristics of the sample by using a second spectrum that is obtained by removing the information of the specified section from the first spectrum.

Description

光學測定系統及光學測定方法Optical measurement system and optical measurement method

本發明係關於能夠測定樣品的膜厚等的光學特性的光學測定系統及光學測定方法。The present invention relates to an optical measurement system and optical measurement method capable of measuring optical characteristics such as the film thickness of a sample.

從先前，已知藉由觀測光干涉所顯現的光，測定樣品的膜厚等光學特性的技術。例如，日本特開2009-092454號公報，揭示能夠以更高的精度測定具有波長依存性的多層膜試料的膜厚的多層膜分析裝置等。此外，日本特開2018-205132號公報，揭示可將樣品膜厚的面內分佈更高速且高精度測定的光學測定裝置等。From the past, there has been known a technique for measuring optical characteristics such as the film thickness of a sample by observing the light that appears by light interference. For example, Japanese Patent Laid-Open No. 2009-092454 discloses a multilayer film analyzer that can measure the film thickness of a wavelength-dependent multilayer film sample with higher accuracy. In addition, Japanese Patent Application Laid-Open No. 2018-205132 discloses an optical measurement device that can measure the in-plane distribution of the sample film thickness at a higher speed and with high accuracy.

使用如上所述的光學測定裝置，測定液晶材料或聚合物材料(例如，PET薄膜等)的樣品膜厚時，根據該等材料所具有的異向性，有使測定精度會降低的課題。此外，測定構造具有複數厚度的樣品時，亦有使測定精度降低的課題。When measuring the thickness of a sample of a liquid crystal material or a polymer material (for example, a PET film, etc.) using the optical measuring device as described above, there is a problem that the measurement accuracy is reduced due to the anisotropy of these materials. In addition, when measuring samples with multiple thicknesses in the structure, there is also a problem of lowering the measurement accuracy.

本發明的一個目標係在於對以先前的光學測定裝置測定精度可能會降低的樣品，亦可以提供更高的精度測定光學特性的構成。An object of the present invention is to provide a configuration that can measure optical characteristics with higher accuracy for samples whose measurement accuracy may be reduced by the conventional optical measurement device.

遵照本發明的一局面的光學測定系統，包含：光源，其係用於產生照射樣品的測定光；分光檢測器，其係用於感應樣品藉由測定光所產生的反射光或穿透光；及處理裝置，其係用於輸入分光檢測器的檢測結果。處理裝置，構成為可執行：根據分光檢測器的檢測結果算出第1光譜的處理；標定在第1光譜，關於波長的振幅變化滿足既定條件的區段的處理；使用從第1光譜去除標定區段資訊的第2光譜算出樣品的光學特性的處理。An optical measurement system in accordance with one aspect of the present invention includes: a light source, which is used to generate measurement light that illuminates the sample; a spectroscopic detector, which is used to sense the reflected light or transmitted light generated by the sample by the measurement light; And a processing device, which is used to input the detection result of the spectroscopic detector. The processing device is configured to execute: processing to calculate the first spectrum based on the detection result of the spectroscopic detector; processing to calibrate the first spectrum, and the processing of the section where the amplitude change of the wavelength satisfies the predetermined condition; using the removal of the calibration area from the first spectrum The second spectrum of the segment information is used to calculate the optical characteristics of the sample.

標定的處理，亦可包含：對第1光譜，依序設定具有預先決定的波長寬幅的評價窗的處理；根據包含在各評價窗的第1光譜的振幅的變化，判斷對應各評價窗的區段是否滿足既定條件的處理。The calibration process may also include: for the first spectrum, the process of sequentially setting evaluation windows with a predetermined wavelength width; based on the change in the amplitude of the first spectrum included in each evaluation window, determining the corresponding evaluation window Whether the section meets the established conditions.

判斷對應各評價窗的區段是否滿足既定條件的處理，亦可包含：算出在對應第1光譜的各評價窗的區段的振幅的誤差程度的處理。The process of determining whether the segment corresponding to each evaluation window satisfies a predetermined condition may also include a process of calculating the degree of error in the amplitude of the segment corresponding to each evaluation window of the first spectrum.

在對應第1光譜的各評價窗的區段的振幅的誤差程度低於既定限值時，亦可判斷對應該評價窗的區段滿足既定條件。When the error degree of the amplitude of the section corresponding to each evaluation window of the first spectrum is lower than a predetermined limit, it can also be determined that the section corresponding to the evaluation window satisfies the predetermined condition.

評價窗的波長寬幅，亦可對每一樣品種類預先設定。 算出樣品光學特性的處理，亦可包含：根據對第2光譜做傅立葉轉換的結果所出現的波峰算出膜厚的處理。The wavelength width of the evaluation window can also be preset for each sample type. The processing for calculating the optical properties of the sample may also include processing for calculating the film thickness based on the peaks that appear as a result of the Fourier transform of the second spectrum.

算出第1光譜的處理，亦可包含：作為第1光譜，根據分光檢測器的檢測結果算出樣品反射率光譜的處理。The process of calculating the first spectrum may also include a process of calculating the sample reflectance spectrum based on the detection result of the spectroscopic detector as the first spectrum.

算出第1光譜的處理，亦可包含：作為第1光譜，從根據分光檢測器的檢測結果算出樣品的反射率光譜，算出去除來自包含在樣品的測定對象外的層的資訊的反射率光譜的處理。The process of calculating the first spectrum may also include: as the first spectrum, calculating the reflectance spectrum of the sample based on the detection result of the spectroscopic detector, and calculating the reflectance spectrum excluding the information from the layer outside the measurement target included in the sample deal with.

算出第1光譜的處理，亦可進一步包含：將樣品的反射率光譜做傅立葉轉換算出第3光譜的處理；標定第3光譜之中，來自包含在樣品中的測定對象外的層的波峰的處理；及將該標定的波峰及該波峰附近的資訊從第3光譜去除算出第4光譜的處理。The processing of calculating the first spectrum may further include: processing the reflectance spectrum of the sample to calculate the third spectrum by Fourier transform; processing of calibrating the peaks from the layer outside the measurement target contained in the sample in the third spectrum ; And the processing of removing the calibrated peak and the information near the peak from the third spectrum to calculate the fourth spectrum.

算出第1光譜的處理，亦可進一步包含：將第4光譜做逆傅立葉轉換算出第1光譜的處理。The process of calculating the first spectrum may further include: performing inverse Fourier transform of the fourth spectrum to calculate the first spectrum.

遵照本發明的一局面的光學測定方法，包含：從光源對樣品照射測定光，根據分光檢測器感應樣品藉由該測定光所產生的反射光或穿透光所得檢測結果，算出第1光譜的步驟；標定在第1光譜，關於波長的振幅變化滿足既定條件的區段的步驟；使用從第1光譜去除標定區段資訊的第2光譜算出樣品的光學特性步驟。 此發明的上述及其他目標、特徵、局面及優點，應可從關於與附圖一起理解的該發明的如下詳細說明更加明瞭。 【圖示之簡單說明】An optical measurement method according to one aspect of the present invention includes: irradiating the sample with measurement light from a light source, and calculating the first spectrum based on the detection result obtained by sensing the reflected light or transmitted light of the sample by the measurement light by the spectroscopic detector Step; Calibration in the first spectrum, the step of wavelength amplitude change meets the predetermined conditions of the step; using the second spectrum to remove the calibration section information from the first spectrum to calculate the optical characteristics of the sample step. The above and other objectives, features, aspects and advantages of this invention should be made clearer from the following detailed description of this invention which is understood together with the accompanying drawings. [Simple description of the icon]

圖1係表示遵照本實施形態的光學測定系統的構成例的示意圖。 圖2係表示包含在遵照本實施形態的光學測定系統的分光檢測器的剖面結構例的示意圖。 圖3係表示包含在遵照本實施形態的光學測定系統的處理裝置的構成例的示意圖。 圖4係用於說明採用光干涉法的光學測定方法的原理的圖。 圖5(A)及(B)係表示根據使用光干涉法的光學測定方法的測定結果的一例的圖。 圖6係用於說明具有異向性的樣品所產生的雙折射的圖。 圖7(A)~(C)係用於說明去除在遵照本實施形態的光學測定方法的低頻波成分影響的方法的圖。 圖8係表示遵照第1實施形態的光學測定方法的程序的流程圖。 圖9(A)~(C)係用於說明標定在遵照第1實施形態的光學測定方法的底段的處理的圖。 圖10係表示遵照圖8所示第1實施形態的光學測定方法的步驟S4的更詳細的程序的流程圖。 圖11(A)~(E)係表示遵照第1實施形態的光學測定方法的測定例的圖。 圖12係表示遵照第2實施形態的光學測定方法的程序的流程圖。 圖13係表示作為測定對象的樣品的結構例的示意圖。 圖14(A)~(E)係示根據遵照第2實施形態的光學測定方法的測定例的圖。Fig. 1 is a schematic diagram showing a configuration example of an optical measurement system according to this embodiment. 2 is a schematic diagram showing an example of the cross-sectional structure of a spectroscopic detector included in the optical measurement system according to the present embodiment. 3 is a schematic diagram showing a configuration example of a processing device included in the optical measurement system according to this embodiment. Fig. 4 is a diagram for explaining the principle of an optical measurement method using optical interferometry. Figs. 5(A) and (B) are diagrams showing an example of measurement results by an optical measurement method using optical interferometry. Fig. 6 is a diagram for explaining the birefringence generated by an anisotropic sample. 7(A) to (C) are diagrams for explaining a method of removing the influence of low-frequency components in the optical measurement method according to the present embodiment. Fig. 8 is a flowchart showing a procedure of the optical measurement method according to the first embodiment. 9(A) to (C) are diagrams for explaining the processing of the calibration in the bottom stage of the optical measurement method according to the first embodiment. Fig. 10 is a flowchart showing a more detailed procedure of step S4 of the optical measurement method according to the first embodiment shown in Fig. 8. 11(A) to (E) are diagrams showing measurement examples in accordance with the optical measurement method of the first embodiment. Fig. 12 is a flowchart showing a procedure of the optical measurement method according to the second embodiment. Fig. 13 is a schematic diagram showing a configuration example of a sample to be measured. 14(A) to (E) are diagrams showing measurement examples according to the optical measurement method according to the second embodiment.

[較佳的實施形態的說明][Description of the preferred embodiment]

關於本發明的實施形態，邊參照圖面詳細說明。再者，關於圖中相同或相當的部分，附以相同符號不重複說明。The embodiments of the present invention will be described in detail with reference to the drawings. In addition, with regard to the same or equivalent parts in the figures, the same symbols will not be repeated.

>A.光學測定系統> 首先，說明關於遵照本實施形態的光學測定系統1的構成例。>A. Optical measurement system> First, a configuration example of the optical measurement system 1 according to this embodiment will be described.

圖1係表示遵照本實施形態的光學測定系統1的構成例的示意圖。光學測定系統1，包含：光源10，其係用於產生照射樣品2的測定光；分光檢測器20，其係用於感應樣品2藉由測定光所產生的觀測光(如後所述的反射光或穿透光)；及處理裝置100，其係輸入分光檢測器20的檢測結果。處理裝置100，係根據分光檢測器20的檢測結果算出樣品2的光學特性(典型為膜厚)。光源10與分光檢測器20，經由具有朝向樣品2的照射口的Y型光纖4，做光學性連接。FIG. 1 is a schematic diagram showing a configuration example of an optical measurement system 1 according to this embodiment. The optical measurement system 1 includes: a light source 10, which is used to generate measurement light that illuminates the sample 2; a spectroscopic detector 20, which is used to sense the observation light generated by the sample 2 by the measurement light (reflected as described later) Light or penetrating light); and the processing device 100, which inputs the detection result of the spectroscopic detector 20. The processing device 100 calculates the optical characteristics (typically film thickness) of the sample 2 based on the detection result of the spectroscopic detector 20. The light source 10 and the spectroscopic detector 20 are optically connected via a Y-shaped optical fiber 4 having an irradiation port facing the sample 2.

在光學測定系統1，藉由從光源10對樣品2照射測定光，觀測在樣品2內部所產生的光干涉所顯現的光，測定包含在樣品2的1或複數膜的膜厚等。In the optical measurement system 1, the sample 2 is irradiated with measurement light from the light source 10, the light generated by the interference of the light generated in the sample 2 is observed, and the film thickness of the 1 or plural films included in the sample 2 is measured.

在圖1作為典型例表示對樣品2照射測定光，觀測樣品2所產生的反射光的反射光學系，惟亦可採用對樣品2照射測定光，觀測穿透樣品2的穿透光的穿透光學系。As a typical example, Figure 1 shows a reflection optical system that irradiates the measurement light to the sample 2 and observes the reflected light generated by the sample 2. However, it is also possible to irradiate the measurement light to the sample 2 to observe the penetration of the transmitted light passing through the sample 2 Department of Optics.

光源10，產生具有既定波長範圍的測定光。測定光的波長範圍，可按照應從樣品2測定的波長資訊的範圍決定。光源10，可使用例如鹵素燈或白色LED等。The light source 10 generates measurement light having a predetermined wavelength range. The wavelength range of the measurement light can be determined based on the range of wavelength information to be measured from sample 2. As the light source 10, for example, a halogen lamp or a white LED can be used.

圖2係表示包含在遵照本實施形態的光學測定系統1的分光檢測器20的剖面結構例的示意圖。參照圖2，分光檢測器20，包含：繞射光柵22，其係將經由Y型光纖4入射的光繞射；受光部24，其係對應繞射光柵22而配置；及界面電路26，其係與受光部24電性連接，用於將檢測結果輸出到處理裝置100。受光部24，係以線性傳感器或2維傳感器等構成，能夠將每個頻率成分的強度作為檢測結果輸出。FIG. 2 is a schematic diagram showing an example of the cross-sectional structure of the spectroscopic detector 20 included in the optical measurement system 1 according to this embodiment. 2, the spectroscopic detector 20 includes: a diffraction grating 22, which diffracts light incident through the Y-shaped optical fiber 4; a light receiving portion 24, which is configured corresponding to the diffraction grating 22; and an interface circuit 26, which It is electrically connected to the light receiving unit 24 and used to output the detection result to the processing device 100. The light receiving unit 24 is constituted by a linear sensor, a two-dimensional sensor, etc., and can output the intensity of each frequency component as a detection result.

圖3係表示包含在遵照本實施形態的光學測定系統1的處理裝置100的構成例的示意圖。參照圖3，處理裝置100，包含：處理器102；主記憶體104；輸入部106；顯示部108；儲存裝置110；通訊界面120；網路界面122；及媒體驅動器124。FIG. 3 is a schematic diagram showing a configuration example of the processing device 100 included in the optical measurement system 1 according to this embodiment. 3, the processing device 100 includes: a processor 102; a main memory 104; an input unit 106; a display unit 108; a storage device 110; a communication interface 120; a network interface 122; and a media driver 124.

處理器102，典型為CPU(Central Processing Unit：中央處理器)或GPU(Graphics Processing Unit：圖形處理器)等演算處理部，將儲藏在儲存裝置110的1或複數程式讀取到主記憶體104而執行。主記憶體104，係DRAM(Dynamic Random Access Memory：動態隨機存取記憶體)或SRAM(Static Random Access Memory：靜態隨機存取記憶體)等揮發性記憶體，作用作為處理器102執行程式的工作記憶體。The processor 102 is typically an arithmetic processing unit such as a CPU (Central Processing Unit) or GPU (Graphics Processing Unit), which reads 1 or a complex number stored in the storage device 110 to the main memory 104 And execute. The main memory 104 is a volatile memory such as DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory), which functions as the work of the processor 102 to execute programs Memory.

輸入部106，包含：鍵盤或滑鼠等，接受來自用戶的操作。顯示部108，係將處理器102執行程式結果等對用戶輸出。The input unit 106 includes a keyboard, a mouse, etc., and accepts operations from the user. The display unit 108 outputs the results of program execution by the processor 102 to the user.

儲存裝置110，係由硬碟、快閃記憶體等的非揮發性記憶體組成，儲藏各種程式或資料。更具體而言，儲存裝置110，係用於保持：作業系統112(OS︰Operating System)；測定程式114；檢測結果116；及測定結果118。The storage device 110 is composed of non-volatile memory such as a hard disk, flash memory, etc., and stores various programs or data. More specifically, the storage device 110 is used to hold: an operating system 112 (OS: Operating System); a measurement program 114; a detection result 116; and a measurement result 118.

作業系統112，提供處理器102執行程式的環境。測定程式114，藉由處理器102執行，實現遵照本實施形態的光學測定方法等。檢測結果116，包含從分光檢測器20所輸出的數據。測定結果118，包含測定程式114的執行所得膜厚等光學特性的計算值。The operating system 112 provides an environment for the processor 102 to execute programs. The measurement program 114 is executed by the processor 102 to realize the optical measurement method according to this embodiment, etc. The detection result 116 includes the data output from the spectroscopic detector 20. The measurement result 118 includes the calculated value of optical properties such as the film thickness obtained by the execution of the measurement program 114.

通訊界面120，係仲介處理裝置100與分光檢測器20之間的數據傳送。網路界面122，係仲介處理裝置100與外部的伺服器裝置之間的數據傳送。The communication interface 120 is used to mediate the data transmission between the processing device 100 and the spectroscopic detector 20. The network interface 122 mediates data transmission between the processing device 100 and an external server device.

媒體驅動器124，係從儲藏在記錄媒體126(例如，光學磁片等)讀取在處理器102執行程式等所需數據，儲藏在儲存裝置110。再者，在處理裝置100執行的測定程式114等，亦可經由記錄媒體126等安裝，亦可經由網路界面122等從伺服裝置下載。The media drive 124 reads data necessary for executing programs and the like on the processor 102 from the recording medium 126 (for example, an optical magnetic sheet, etc.) stored in the storage device 110. Furthermore, the measurement program 114 and the like executed on the processing device 100 may also be installed via the recording medium 126 or the like, or downloaded from the server device via the network interface 122 or the like.

測定程式114，可為作為作業系統112的一部分提供的程式模組之中，將所需模組以既定的排列，以既定的時機叫出執行處理。此種情形，關於不含該模組的測定程式114，亦包含在本發明的技術上範圍。測定程式114，亦可組入其他程式的一部分來提供。The measurement program 114 may be among the program modules provided as a part of the operating system 112, and the required modules are arranged in a predetermined arrangement and called for execution at a predetermined timing. In this case, the measurement program 114 without the module is also included in the technical scope of the present invention. The measurement program 114 can also be provided as part of other programs.

再者，亦可將以處理裝置100的處理器102執行測定程式114所提供的功能的全部或一部分，藉由專用的硬體實現。Furthermore, all or part of the functions provided by the processor 102 of the processing device 100 to execute the measurement program 114 may be implemented by dedicated hardware.

>B. 課題及解決手段> 接著，說明在關於由本案發明者們所新發現之採用光干涉法的光學測定方法所發生的課題。>B. Issues and solutions> Next, a description will be given of the problems that occurred in the optical measurement method using the optical interferometry newly discovered by the inventors of the present application.

圖4係用於說明使用光干涉法的光學測定方法的原理的圖。參照圖4，作為最簡單的例子，假定由介質1(折射率n1 )所組成的樣品2(膜厚d1 )。樣品2的紙面上側與介質0(折射率n0 )相接，樣品2的紙面下側與介質2(折射率n2 )相接。Fig. 4 is a diagram for explaining the principle of an optical measurement method using optical interferometry. Referring to FIG. 4, as the most simple example, assume that a sample from the medium (refractive index n-1) consisting of 2 (thickness d 1). The upper side of the paper surface of the sample 2 is in contact with medium 0 (refractive index n 0 ), and the lower side of the paper surface of the sample 2 is in contact with the medium 2 (refractive index n 2 ).

在如此的狀態，從配置在介質0側的光源向樣品2照射測定光。測定光的一部分，在樣品2的入射面(介質0與介質1的界面)反射(反射率R1 )。測定光的其他的一部分，入射樣品2在樣品2內傳播之後，在相反側的面(介質1與介質2的界面)反射，進一步在樣品2內對逆方向傳播穿透入射面(反射率R2 )。再者，雖未示於圖，在樣品2內發生多重反射，結果可觀測到對應從樣品2射出的光的反射光。In such a state, the sample 2 is irradiated with measurement light from the light source arranged on the medium 0 side. A part of the measurement light is reflected on the incident surface of the sample 2 (the interface between the medium 0 and the medium 1) (reflectance R 1 ). The other part of the measuring light is measured. After the incident sample 2 propagates in the sample 2, it reflects on the opposite side (the interface between the medium 1 and the medium 2), and further propagates through the incident surface in the opposite direction in the sample 2 (reflectance R 2 ). In addition, although not shown in the figure, multiple reflections occurred in the sample 2, and as a result, reflected light corresponding to the light emitted from the sample 2 was observed.

對如此的測定光，在樣品2的表面及樣品2內所產生的各個反射光全體的反射率R012，成為各反射率的共計(R1+R2+R3+‧‧‧)。如以下的(1-1)式所示，反射率R012，成為複反射率r012 的平方值。此外，複反射率r012 ，係遵照以下的(1-2)式算出。再者，(1-2)式中的相位β，係遵照以下的(1-3)式算出。For such measurement light, the total reflectance R012 of each reflected light generated on the surface of the sample 2 and the sample 2 becomes the total reflectance (R1+R2+R3+‧‧‧). As shown in the following equation (1-1), the reflectance R012 becomes the square value of the complex reflectance r 012 . In addition, the complex reflectance r 012 is calculated according to the following equation (1-2). Furthermore, the phase β in the equation (1-2) is calculated according to the following equation (1-3).

Figure 02_image001
其中，r01 為介質0與介質1的界面的反射率 r12 質1與介質2的界面的反射率
Figure 02_image003
Figure 02_image001
Where r 01 is the reflectance of the interface between medium 0 and medium 1 r 12 is the reflectance of the interface between medium 1 and medium 2
Figure 02_image003

再者，上述(1-1)~(1-3)式，係表示關於具有標定波長λ的測定光的反射率，惟在圖1所示光學測定系統1，係使用具有既定波長範圍的測定光的同時，使用分光檢測器20觀測每個波長的反射光(或，穿透光)，故可測定樣品2的每個波長的反射率(以下稱為「反射率光譜」。)。反射率光譜相當於分光反射率。Furthermore, the above equations (1-1) to (1-3) indicate the reflectance of the measurement light with the calibration wavelength λ, but the optical measurement system 1 shown in Figure 1 uses a measurement with a predetermined wavelength range Simultaneously with light, the spectroscopic detector 20 is used to observe the reflected light (or transmitted light) of each wavelength, so the reflectance of each wavelength of the sample 2 can be measured (hereinafter referred to as "reflectance spectrum"). The reflectance spectrum corresponds to the spectral reflectance.

根據將測定的反射率光譜做傅立葉轉換所得功率譜所顯現的波峰，可算出對象的樣品2的膜厚或包含在樣品2的各層的膜厚。再者關於使用從穿透光被算出的透過率光譜的場合也同樣能算出包含在對象的樣品2的膜厚或樣品2中的各層的膜厚。From the peaks of the power spectrum obtained by Fourier transforming the measured reflectance spectrum, the film thickness of the target sample 2 or the film thickness of each layer included in the sample 2 can be calculated. Furthermore, in the case of using the transmittance spectrum calculated from the transmitted light, the film thickness of the target sample 2 or the film thickness of each layer in the sample 2 can be calculated similarly.

圖5係表示示使用光干涉法的光學測定方法的測定結果的一例。在圖5(A)表示從具有異向性的樣品所測定的反射率光譜的一例，在圖5(B)表示從圖5(A)的反射率光譜所算出的功率譜的一例。再者，圖5(B)的橫軸，係對膜厚d乘上各波長的折射率n(λ)的值(以下，記述為「光學膜厚」或「nd」。)。Fig. 5 shows an example of the measurement result of the optical measurement method using the optical interferometry. FIG. 5(A) shows an example of a reflectance spectrum measured from a sample having anisotropy, and FIG. 5(B) shows an example of a power spectrum calculated from the reflectance spectrum of FIG. 5(A). In addition, the horizontal axis of FIG. 5(B) is the value obtained by multiplying the film thickness d by the refractive index n(λ) of each wavelength (hereinafter, referred to as "optical film thickness" or "nd").

如圖5(A)所示，反射率光譜，顯示振幅的大小對波長週期性變動的特性。在圖5(B)所示功率譜，出現三個波峰P1、P2、P3。但是，近接的波峰P1與波峰P2係對應同一層，原本應該出現在同一位置。即，應該在波峰P1與波峰P2之間出現真的波峰。存在波峰P1及波峰P2，則可能誤判而輸出各個膜厚作為測定結果。As shown in Fig. 5(A), the reflectance spectrum shows the characteristic that the amplitude of the amplitude varies periodically with respect to the wavelength. In the power spectrum shown in Figure 5(B), three peaks P1, P2, P3 appear. However, the adjacent peaks P1 and P2 correspond to the same layer and should originally appear in the same position. That is, a true peak should appear between the peak P1 and the peak P2. If there is a peak P1 and a peak P2, it may be misjudged and each film thickness is output as a measurement result.

在如此的近接位置發生兩個波峰的理由之一，可考慮樣品具有異向性。One of the reasons why two peaks occur at such a close position is that the sample has anisotropy.

圖6係用於說明具有異向性的樣品所產生的雙折射的圖。異向性，係意指根據觀測方向看起來(光學特性)不同。參照圖6，在具有異向性的樣品，對某軸方向(x軸)的折射率nx ，與正交於該軸方向的軸方向(y軸)的折射率ny 未必一致(即nx ≠ny )。如圖5(B)所示，近接的兩個波峰，可認為是如此的折射率的軸間的些許差Δn(=|nx ny |)的影響。Fig. 6 is a diagram for explaining the birefringence generated by an anisotropic sample. Anisotropy means that it looks different (optical characteristics) depending on the viewing direction. Referring to FIG 6, the sample having the anisotropy of refractive index n of an X-axis direction (x-axis) orthogonal to the axial direction (y-axis) in the axial direction Y of the refractive index n does not necessarily match (i.e., n x ≠n y ). As shown in Figure 5(B), the two adjacent peaks can be considered to be affected by the slight difference Δn (=|n x n y |) between the axes of the refractive index.

此外，不只是異向性，亦有依存於樣品的構造，出現近接的複數波峰。再者，具有多層結構的樣品具有異向性時，會在各層發生雙折射的影響。In addition, not only the anisotropy, but also the structure that depends on the sample, the complex peaks appear close. Furthermore, when a sample with a multilayer structure has anisotropy, the effect of birefringence will occur in each layer.

如此地，以光干涉法測定具有異向性的樣品或具有特異構造的樣品時，包含在測定結果的誤差有時會變大。再者，關於具有多層結構的樣品，如此的誤差增大會在各層發生。In this way, when a sample with anisotropy or a sample with a specific structure is measured by optical interferometry, the error included in the measurement result may increase. Furthermore, for samples with a multi-layer structure, such an increase in error will occur in each layer.

在此，起因於異向性的雙折射(折射率的差異)為唯一的原因，則可考慮使用偏光板等只觀測標定軸方向的光來解決。但是，現實上，依存於樣品與偏光板的光學性位置關係(角度)，而包含在觀測光的成分會變化，故測定時需要嚴密的調整光學性位置關係。因此，在依序測定複數樣品等的應用，現實上難以適用。Here, birefringence (difference in refractive index) due to anisotropy is the only cause, and it can be solved by observing only light in the calibration axis direction, such as using a polarizing plate. However, in reality, it depends on the optical positional relationship (angle) between the sample and the polarizing plate, and the component included in the observation light changes. Therefore, it is necessary to strictly adjust the optical positional relationship during measurement. Therefore, it is practically difficult to apply to applications such as the sequential measurement of plural samples.

解決使用如上所述的光干涉法的光學測定方法所發生的課題的手段，概略如下。The outline of the means for solving the problems caused by the optical measurement method using the optical interferometry as described above is as follows.

在具有如上所述的異向性的樣品所觀測的光反射率光譜，會產生起伏(拍擊)。如此的「起伏」，泛化，則已知振動數僅少許不同的波浪的合成波的振幅週期性反複強弱的現象。例如，看從具有雙折射率nx 、ny 的樣品所測定的反射率光譜，則可使用如下(2)式的關係式泛化。The light reflectance spectrum observed on a sample having the anisotropy as described above may fluctuate (slap). Such "fluctuations" and generalization are known as the phenomenon that the amplitude of the composite wave of waves with only slightly different vibration numbers repeats strength and weakness periodically. For example, looking at the reflectance spectrum measured from a sample having birefringence n x and n y , the following relational expression (2) can be used to generalize.

Figure 02_image005
其中，I：振幅強度
Figure 02_image007
C：切片
Figure 02_image005
Among them, I: amplitude intensity
Figure 02_image007
C: Slice

如(2)式所示，反射率光譜，包含：依存於雙折射率差(nx -ny )的頻率成分(以下稱為「低頻波成分」。)；及依存於雙折射率和(nx +ny )的頻率成分(以下稱為「高頻波成分」。)。在此，低頻波成分係意指振幅變化的週期(波長的長度)相對較長的成分，高頻波成分係意指振幅變化的週期(波長的長度)相對較短的成分。As shown in equation (2), the reflectance spectrum includes: frequency components dependent on the birefringence difference (n x -n y ) (hereinafter referred to as "low frequency components"); and dependent on the birefringence sum ( n x +n y ) frequency components (hereinafter referred to as "high frequency components"). Here, the low-frequency wave component means a component with a relatively long period of amplitude change (length of wavelength), and a high-frequency wave component means a component with a relatively short period of amplitude change (length of wavelength).

相當於該等頻率成分之中，實際測定對象係相當於膜厚的平均值，係依存於雙折射率和(nx +ny )的高頻波成分，依存於雙折射率差(nx -ny )的低頻波成分係實際上不存在的疑似資訊(即，誤差要因)。Among these frequency components, the actual measurement object corresponds to the average value of the film thickness, which depends on the birefringence and the high frequency components of (n x +n y ), and depends on the birefringence difference (n x -n The low-frequency wave component of y ) is suspected information (that is, the error factor) that does not actually exist.

例如，聲波等的振幅為經時變化的波，則可藉由充分長時間觀測，測定低頻波成分。但由於關於光波無法做時間區域的觀測，故依存於光源及分光檢測器的性能，可觀測的波長範圍被固定地決定。此外，按照欲測定的膜厚(高頻波成分)，決定波長範圍及波長解析度，故在同樣的測定內，並不容易觀測低頻波成分的波。For example, if the amplitude of a sound wave or the like is a wave that changes over time, it is possible to measure the low-frequency wave component by observing for a long enough time. However, since light waves cannot be observed in the time zone, depending on the performance of the light source and the spectroscopic detector, the observable wavelength range is fixedly determined. In addition, the wavelength range and wavelength resolution are determined in accordance with the film thickness (high-frequency component) to be measured. Therefore, it is not easy to observe low-frequency components in the same measurement.

因此，當在可觀測的波長範圍，包含低頻波成分的至少一部份，則測定誤差可能會增大。即，被觀測的光，係低頻波成分與高頻波成分的混波，故會對實際測定對象的高頻波成分(即，表示膜厚的資訊)造成影響。由於低頻波成分的頻率(振幅變化的週期)依存於樣品，故無法預知。Therefore, when the observable wavelength range contains at least a part of the low-frequency wave component, the measurement error may increase. That is, the light to be observed is a mixture of low-frequency wave components and high-frequency wave components, so it affects the high-frequency wave components of the actual measurement target (that is, information indicating the film thickness). Since the frequency of the low-frequency wave component (the period of amplitude change) depends on the sample, it cannot be predicted.

圖7係用於說明去除在遵照本實施形態的光學測定方法的低頻率成分影響的方法的圖。在圖7(A)表示反射率光譜的低頻波成分的一例，在圖7(B)表示反射率光譜的高頻波成分的一例，在圖7(C)表示將低頻波成分及高頻波成分混波的反射率光譜的一例。再者，在說明的權宜上，在圖7表示單純化的波形。FIG. 7 is a diagram for explaining a method of removing the influence of low-frequency components in the optical measurement method according to this embodiment. Fig. 7(A) shows an example of the low-frequency wave component of the reflectance spectrum, Fig. 7(B) shows an example of the high-frequency wave component of the reflectance spectrum, and Fig. 7(C) shows the mixing of the low-frequency wave component and the high-frequency wave component An example of reflectance spectrum. Furthermore, for expediency of explanation, FIG. 7 shows a simplified waveform.

圖7(A)所示反射率光譜的低頻波成分之中，著眼於振幅小的區段的底段(節)，則對應的反射率光譜的高頻波成分(圖7(B))雖存在振幅，但在圖7(C)所示合成波的反射率光譜，振幅變小，可知失去顯示膜厚的資訊。如此的失去顯示膜厚的資訊，可能成為測定誤差的要因。Among the low-frequency components of the reflectance spectrum shown in Figure 7(A), focusing on the bottom section (section) of the region with small amplitude, the corresponding high-frequency components of the reflectance spectrum (Figure 7(B)) have amplitudes However, in the reflectance spectrum of the composite wave shown in FIG. 7(C), the amplitude becomes smaller, and it can be seen that the information indicating the film thickness is lost. Such loss of information indicating the film thickness may become a main cause of measurement errors.

本案發明者們，著眼於如上所述的發生在反射率光譜的低頻波成分的底段(節)為測定誤差的要因，將測定的反射率光譜之中，標定低頻波成分的底段的同時，將該標定的底段的至少一部分的資訊，及/或，在底段附近的資訊去除之後，算出光學特性。藉由去除如此的底段的至少一部分及底段附近的資訊，防止測定精度的下降。The inventors of the present case focused on the bottom band (node) of the low-frequency component occurring in the reflectance spectrum as the main cause of the measurement error, and the bottom band of the low-frequency component was calibrated in the measured reflectance spectrum. , Calculate the optical characteristics after removing at least part of the information of the calibrated bottom segment, and/or after removing the information near the bottom segment. By removing at least a part of such a bottom segment and information near the bottom segment, a decrease in measurement accuracy is prevented.

以下，說明關於本案發明者們所發現的技術思想的具體化例。 >C. 第1實施形態> 作為第1實施形態，說明包含在從樣品測定的反射率光譜的頻率成分(波峰)的數量相對較少時的處理。遵照第1實施形態的光學測定方法，典型上可適用在測定關於單層膜的樣品的膜厚等。Hereinafter, specific examples of the technical ideas discovered by the inventors of the present application will be described. >C. The first embodiment> As the first embodiment, a description will be given of processing when the number of frequency components (peaks) of the reflectance spectrum measured from the sample is relatively small. The optical measurement method according to the first embodiment is typically applicable to measurement of the film thickness of a sample of a single-layer film.

(c1:處理程序) 首先，說明關於遵照第1實施形態的光學測定方法的處理程序。(c1: handler) First, the processing procedure of the optical measurement method according to the first embodiment will be described.

圖8表示遵照第1實施形態的光學測定方法的程序的流程圖。在圖8所示主要步驟，典型上可藉由處理裝置100的處理器102將測定程式114(均參照圖3)展開到主記憶體104執行而實現。Fig. 8 shows a flowchart of a procedure of the optical measurement method according to the first embodiment. The main steps shown in FIG. 8 are typically implemented by the processor 102 of the processing device 100 expanding the measurement program 114 (all refer to FIG. 3) to the main memory 104 for execution.

參照圖8，首先，準備光學測定系統1(步驟S1)。在步驟S1，執行包含在光學測定系統1的Y型光纖4的照射口的對位，或分光檢測器20的校正處理等。然後，在光學測定系統1的既定位置配置測定對象的樣品2(步驟S2)。Referring to Fig. 8, first, the optical measurement system 1 is prepared (step S1). In step S1, the alignment of the irradiation port of the Y-type optical fiber 4 included in the optical measurement system 1, the calibration processing of the spectroscopic detector 20, and the like are executed. Then, the sample 2 to be measured is arranged at a predetermined position of the optical measurement system 1 (step S2).

接著，從光源10向樣品2照射測定光，根據分光檢測器20感應樣品2藉由該測定光所產生的反射光或穿透光所得檢測結果，執行算出光譜的處理。在第1實施形態，作為算出光譜的處理，執行根據分光檢測器20的檢測結果算出樣品2的反射率光譜的處理。Next, the sample 2 is irradiated with measurement light from the light source 10, and the spectroscopic detector 20 senses the reflected light or transmitted light of the sample 2 by the measurement light to perform the processing of calculating the spectrum. In the first embodiment, as the process of calculating the spectrum, the process of calculating the reflectance spectrum of the sample 2 based on the detection result of the spectroscopic detector 20 is executed.

更具體而言，藉由分光檢測器20感應，對樣品2照射來自光源10的測定光所產生的反射光，測定反射率光譜(步驟S3)。根據分光檢測器20的檢測結果算出樣品2的反射率光譜的處理，可以分光檢測器20執行，亦可以處理裝置100執行。在步驟S3所測定的反射率光譜，作為檢測結果116(參照圖3)，儲藏在處理裝置100的儲存裝置110。More specifically, the sample 2 is irradiated with the reflected light from the measurement light from the light source 10 by the spectroscopic detector 20 to measure the reflectance spectrum (step S3). The processing of calculating the reflectance spectrum of the sample 2 based on the detection result of the spectroscopic detector 20 may be executed by the spectroscopic detector 20 or the processing device 100. The reflectance spectrum measured in step S3 is stored in the storage device 110 of the processing device 100 as the detection result 116 (see FIG. 3).

再者，作為算出光譜的處理，亦可採用根據分光檢測器20的檢測結果，算出樣品2的穿透率光譜的處理。In addition, as the process of calculating the spectrum, a process of calculating the transmittance spectrum of the sample 2 based on the detection result of the spectroscopic detector 20 may also be adopted.

接著，處理裝置100，在算出的光譜，執行標定關於波長的振幅變化滿足既定條件的區段的處理。更具體而言，處理裝置100，係標定包含在所測定的反射率光譜的低頻波成分的底段，去除該標定的底段資訊(步驟S4)。Next, the processing device 100 executes a process of calibrating the section where the amplitude change with respect to the wavelength satisfies a predetermined condition on the calculated spectrum. More specifically, the processing device 100 calibrates the bottom band of the low-frequency components included in the measured reflectance spectrum, and removes the calibrated bottom band information (step S4).

然後，處理裝置100，係使用從算出的光譜去除標定區段的資訊後的光譜執行算出樣品2的光學特性的處理。Then, the processing device 100 executes the process of calculating the optical characteristics of the sample 2 using the spectrum obtained by removing the information of the calibration section from the calculated spectrum.

更具體而言，處理裝置100，係將去除底段資訊的反射率光譜做傅立葉轉換算出功率譜(步驟S5)。再者，傅立葉轉換，典型上亦可使用FFT(Fast Fourier Transform︰高速傅立葉轉換法)。再者，處理裝置100，搜尋包含在步驟S5所算出的功率譜的波峰(步驟S6)，根據所搜尋的波峰在功率譜上的位置，作為樣品2的光學特性，算出樣品2的膜厚(步驟S7)。然後，結束光學測定的處理。More specifically, the processing device 100 performs Fourier transform on the reflectance spectrum from which the bottom segment information is removed to calculate the power spectrum (step S5). Furthermore, for Fourier transform, FFT (Fast Fourier Transform: Fast Fourier Transform) can also be typically used. Furthermore, the processing device 100 searches for the peaks included in the power spectrum calculated in step S5 (step S6), and calculates the film thickness of the sample 2 based on the position of the searched peak on the power spectrum as the optical characteristics of the sample 2 ( Step S7). Then, the optical measurement process ends.

如步驟S5~S7所示，算出樣品2的光學特性的處理，包含根據對去除底段資訊的反射率光譜做傅立葉轉換的結果所出現的波峰算出膜厚的處理。再者，如步驟S5~S7所示，有關用於算出樣品2的膜厚的詳細的處理程序，可參照例如，日本特開2009-092454號公報(專利文獻1)。As shown in steps S5 to S7, the process of calculating the optical characteristics of the sample 2 includes a process of calculating the film thickness based on the peaks that appear as a result of Fourier transform of the reflectance spectrum with the bottom band information removed. In addition, as shown in steps S5 to S7, for the detailed processing procedure for calculating the film thickness of the sample 2, refer to, for example, Japanese Patent Application Laid-Open No. 2009-092454 (Patent Document 1).

再者，將樣品2的膜厚持續測定數次，或需要將樣品2的膜厚測定複數處時，將步驟S3~S7的處理重複執行所需次數。Furthermore, when the film thickness of the sample 2 is continuously measured several times, or the film thickness of the sample 2 needs to be measured in multiple places, the processing of steps S3 to S7 is repeated as many times as necessary.

(c2： 底段的標定) 接著，說明關於圖8的步驟S4所示標定底段的處理的細節。(c2: Calibration of the bottom section) Next, the details of the process of calibrating the bottom stage shown in step S4 of FIG. 8 will be described.

標定底段的處理，係在反射率光譜，標定相當於有關波長的振幅變化滿足既定條件的區段的處理。在此，既定條件，係意指包含在反射率光譜中的低頻波成分的振幅相對較小。換言之，既定條件，係意指反射率光譜相當於波的節的部分。The processing of the bottom section of the calibration is based on the reflectance spectrum, and the calibration is equivalent to the processing of the section where the amplitude change of the relevant wavelength meets the established conditions. Here, the predetermined condition means that the amplitude of the low-frequency wave component contained in the reflectance spectrum is relatively small. In other words, the established condition means the part of the reflectance spectrum that corresponds to the node of the wave.

在第1實施形態，根據在反射率光譜的單位段所產生的振幅變動的大小，標定底段。越近接駐波的節，振幅的變動會變小，近接駐波的波腹，振幅會大大地變動。因此，評價每個單位段的振幅變動的大小，將振幅變動相對較小的區段標定作為底段。In the first embodiment, the bottom segment is calibrated based on the magnitude of the amplitude fluctuation generated in the unit segment of the reflectance spectrum. The closer to the node of the standing wave, the smaller the amplitude variation, and the closer to the antinode of the standing wave, the greater the amplitude variation. Therefore, the magnitude of the amplitude variation of each unit segment is evaluated, and the segment with relatively small amplitude variation is calibrated as the bottom segment.

圖9係用於說明標定在遵照第1實施形態的光學測定方法的底段的處理的圖。在圖9(A)表示從樣品測定的反射率光譜的一例。對圖9(A)所示反射率光譜，邊偏移波長位置依序設定具有預先設定的波長寬幅的評價窗30。根據包含在反射率光譜的各評價窗30的區段資訊，算出顯示振幅變動大小的資訊。FIG. 9 is a diagram for explaining the processing of the calibration at the bottom stage of the optical measurement method according to the first embodiment. Fig. 9(A) shows an example of the reflectance spectrum measured from the sample. For the reflectance spectrum shown in FIG. 9(A), the evaluation window 30 having a preset wavelength width is sequentially set at the edge shift wavelength position. Based on the segment information included in each evaluation window 30 of the reflectance spectrum, information showing the magnitude of amplitude fluctuation is calculated.

如此，標定底段的處理，包含：對反射率光譜，依序設定具有預先設定的波長寬幅的評價窗30的處理；及根據包含在各評價窗30的反射率光譜的振幅變化，判斷對應各評價窗30的區段是否滿足既定條件的處理。In this way, the process of calibrating the bottom stage includes: sequentially setting the evaluation windows 30 with preset wavelength widths for the reflectance spectrum; and judging the correspondence based on the amplitude changes of the reflectance spectra included in each evaluation window 30 Whether the segment of each evaluation window 30 satisfies a predetermined condition.

作為是否滿足既定條件的振幅變化，能夠使用對應各評價窗30內的區段的振幅的誤差程度。即，處理裝置100，作為判斷對應各評價窗30的區段是否滿足既定條件的處理的一部分，執行算出對應反射率光譜的各評價窗的區段的振幅的誤差程度的處理。As the amplitude change that satisfies a predetermined condition, the degree of error corresponding to the amplitude of the segment in each evaluation window 30 can be used. In other words, the processing device 100 performs a process of calculating the degree of error in the amplitude of each evaluation window segment corresponding to the reflectance spectrum as part of the process of determining whether the segment corresponding to each evaluation window 30 satisfies a predetermined condition.

作為振幅的誤差程度，典型上能夠使用分散或標準偏差。或者，亦可使用存在於各評價窗30內的振幅的最大值與最小值的差。如此，作為表示在對應各評價窗30內的區段的振幅的誤差程度的資訊，能夠使用任意值。在以下的說明，作為典型例，使用「分散」的例子。As the degree of error in amplitude, dispersion or standard deviation can typically be used. Alternatively, the difference between the maximum value and the minimum value of the amplitude existing in each evaluation window 30 may also be used. In this way, any value can be used as information indicating the degree of error in the amplitude of the segment corresponding to each evaluation window 30. In the following description, the example of "dispersion" is used as a typical example.

在圖9(B)表示，對圖9(A)所示的反射率光譜依序設定評價窗30所算出的每個波長的分散(以下稱為「分散光譜」。)。藉由對圖9(B)所示分散光譜進行評價，標定底段。In FIG. 9(B), the dispersion for each wavelength calculated by the evaluation window 30 is sequentially set for the reflectance spectrum shown in FIG. 9(A) (hereinafter referred to as "dispersion spectrum"). By evaluating the dispersion spectrum shown in Figure 9(B), the bottom segment is calibrated.

作為典型例，對圖9(B)所示分散光譜，預先設定限值，將分散值低於既定限值的區段標定作為底段32。即，處理裝置100，在對應反射率光譜的各評價窗30的區段的振幅的誤差程度(作為一例，分散)低於既定限值時，判斷對應該評價窗30的區段滿足既定條件。As a typical example, for the dispersion spectrum shown in FIG. 9(B), a limit is set in advance, and a segment with a dispersion value lower than the predetermined limit is calibrated as the bottom segment 32. That is, the processing device 100 determines that the section corresponding to the evaluation window 30 satisfies the predetermined condition when the degree of error (as an example, dispersion) of the amplitude of the section of each evaluation window 30 corresponding to the reflectance spectrum is lower than a predetermined limit.

再者，評價窗30的波長寬幅，根據反射率光譜全體的波長範圍及波長解析度等適當決定。或者，亦可動態調整評價窗30的波長寬幅，以確保既定的測定精度。此外，限值，可為預先決定的固定值，亦可根據算出的分散光譜全體的振幅變動的大小動態決定。In addition, the wavelength width of the evaluation window 30 is appropriately determined according to the wavelength range of the entire reflectance spectrum, the wavelength resolution, and the like. Alternatively, the wavelength width of the evaluation window 30 may be dynamically adjusted to ensure a predetermined measurement accuracy. In addition, the limit may be a predetermined fixed value, or may be dynamically determined based on the magnitude of the calculated amplitude variation of the entire dispersion spectrum.

再者，評價窗30的波長寬幅，及/或限值的大小，亦可對每個樣品2的種類預先設定。此時，處理裝置100，亦可將每個樣品2的種類預先儲藏配方資訊，按照測定對象的樣品2的種類，將對應的配方資訊有效化。Furthermore, the wavelength width of the evaluation window 30 and/or the size of the limit can also be preset for each type of sample 2. In this case, the processing device 100 may store the recipe information for each type of sample 2 in advance, and validate the corresponding recipe information according to the type of sample 2 to be measured.

如圖9(C)所示，反射率光譜之中，去除標定底段資訊。再者，在算出樣品膜厚的過程，將反射率光譜做傅立葉轉換。因此，在標定底段的資訊去除，亦可執行使對應波長的振幅(反射率)更新為零(或者，預先設定的基準值)的處理。As shown in Figure 9(C), in the reflectance spectrum, the calibration bottom band information is removed. Furthermore, in the process of calculating the film thickness of the sample, the reflectance spectrum is Fourier transformed. Therefore, when the information in the bottom segment of the calibration is removed, the processing of updating the amplitude (reflectivity) of the corresponding wavelength to zero (or a preset reference value) can also be performed.

藉由如此的一連串處理，完成標定所測定的反射率光譜中的低頻波成分的底段、及去除該標定的底段資訊。Through such a series of processing, the bottom band of the low-frequency wave component in the measured reflectance spectrum is calibrated and the bottom band information of the calibration is removed.

圖10係表示遵照圖8所示第1實施形態的光學測定方法的步驟S4的更詳細的程序的流程圖。參照圖10，處理裝置100，對測定的反射率光譜，將評價窗30設定在初期位置(步驟S41)。處理裝置100，算出關於設定的評價窗30內的反射率光譜的區段的分散(步驟S42)。處理裝置100，判斷是否對所有位置完成設定評價窗30(步驟S43)。Fig. 10 is a flowchart showing a more detailed procedure of step S4 of the optical measurement method according to the first embodiment shown in Fig. 8. 10, the processing device 100 sets the evaluation window 30 at the initial position for the measured reflectance spectrum (step S41). The processing device 100 calculates the dispersion of the segments of the reflectance spectrum in the set evaluation window 30 (step S42). The processing device 100 determines whether the evaluation window 30 has been set for all positions (step S43).

若尚未對所有位置完成設定評價窗30的設定(在步驟S43為NO)，則處理裝置100，在下一個位置設定評價窗30(步驟S44)。然後，重複步驟S42以下的處理。If the setting of the evaluation window 30 has not been completed for all positions (NO in step S43), the processing device 100 sets the evaluation window 30 in the next position (step S44). Then, the processing after step S42 is repeated.

若對所有位置完成評價窗30的設定(在步驟S43為YES)，則處理裝置100，根據對各評價窗30所算出的分散，算出分散光譜(步驟S45)，標定在算出的分散光譜低於限值的區段作為底段32(步驟S46)。然後，處理裝置100，將包含在標定的底段32的各波長的反射率更新為零(步驟S47)。If the setting of the evaluation window 30 is completed for all positions (YES in step S43), the processing device 100 calculates a dispersion spectrum based on the dispersion calculated for each evaluation window 30 (step S45), and is calibrated when the calculated dispersion spectrum is lower than The section of the limit value is used as the bottom section 32 (step S46). Then, the processing device 100 updates the reflectance of each wavelength included in the calibrated bottom segment 32 to zero (step S47).

根據以上步驟，完成包含所測定的反射率光譜的低頻波成分的底段的標定、及去除該標定的底段資訊的處理。According to the above steps, the calibration of the bottom band including the low frequency components of the measured reflectance spectrum and the processing of removing the bottom band information of the calibration are completed.

(c3： 測定例) 接著，說明關於遵照第1實施形態的光學測定方法的測定例。(c3: Measurement example) Next, a measurement example according to the optical measurement method of the first embodiment will be described.

圖11係表示遵照第1實施形態的光學測定方法的測定例的圖。在圖11(A)表示從具有異向性的樣品所測定的反射率光譜的一例。在圖11(B)表示將圖11(A)所示反射率光譜直接傅立葉轉換所得的功率譜的一例。如圖11(B)所示，將從具有異向性的樣品所測定的反射率光譜直接傅立葉轉換時，會在近接的位置顯現複數波峰，而可能降低測定精度。Fig. 11 is a diagram showing a measurement example according to the optical measurement method of the first embodiment. FIG. 11(A) shows an example of a reflectance spectrum measured from a sample having anisotropy. FIG. 11(B) shows an example of a power spectrum obtained by direct Fourier conversion of the reflectance spectrum shown in FIG. 11(A). As shown in FIG. 11(B), when the reflectance spectrum measured from an anisotropic sample is directly Fourier-transformed, complex peaks appear at close positions, which may reduce the measurement accuracy.

在圖11(C)表示藉由對圖11(A)所示反射率光譜依序設定評價窗30所算出的分散光譜的一例。將低於對圖11(C)所示分散光譜設定的限值的區段，標定作為底段32。然後，藉由將包含在底段32的各波長的反射率更新為零，得到如圖11(D)所示去除底段資訊的反射率光譜。FIG. 11(C) shows an example of the dispersion spectrum calculated by sequentially setting the evaluation window 30 for the reflectance spectrum shown in FIG. 11(A). The section below the limit set for the dispersion spectrum shown in FIG. 11(C) is calibrated as the bottom section 32. Then, by updating the reflectance of each wavelength included in the bottom segment 32 to zero, a reflectance spectrum with the bottom segment information removed as shown in FIG. 11(D) is obtained.

藉由將如圖11(D)所示去除底段資訊的反射率光譜做傅立葉轉換，如圖11(E)所示，可抑制發生近接的波峰，根據這個防止測定精度的下降。By performing Fourier transform on the reflectance spectrum with the bottom band information removed as shown in Fig. 11(D), as shown in Fig. 11(E), the occurrence of close peaks can be suppressed, thereby preventing the decrease of measurement accuracy.

(c4： 優點) 根據遵照第1實施形態的光學測定方法，去除出現在從具有異向性的樣品等所測定的光譜的起伏(根據不同頻率成分的組合的變動)的影響之後，算出樣品的光學特性。因此，能夠抑制測定精度的下降。(c4: advantages) According to the optical measurement method according to the first embodiment, the optical characteristics of the sample are calculated after removing the influence of the fluctuation (variation according to the combination of different frequency components) of the spectrum measured from a sample having anisotropy. Therefore, it is possible to suppress a decrease in measurement accuracy.

>D. 第2實施形態> 在第1實施形態，作為一例說明了具有異向性的單層膜樣品。 實際的樣品大多由複數層組成的多層膜。測定具有異向性的多層膜樣品時，不只是產生起因於雙折射率的起伏(拍擊)的層的影響，亦會受到來自其他層的影響，有時難以去除起伏的影響。因此，作為第2實施形態，說明關於適於測定多層膜樣品的膜厚的光學測定方法。>D. The second embodiment> In the first embodiment, a single-layer film sample having anisotropy is described as an example. The actual samples are mostly multilayer films composed of multiple layers. When measuring an anisotropic multilayer film sample, not only the influence of the layer caused by the fluctuation (slap) of the birefringence is generated, but also the influence from other layers is generated, and it is sometimes difficult to remove the influence of the fluctuation. Therefore, as a second embodiment, an optical measurement method suitable for measuring the film thickness of a multilayer film sample will be described.

(d1: 處理概要) 首先，說明關於遵照第2實施形態的光學測定方法的處理概要。(d1: Summary of processing) First, the outline of the processing of the optical measurement method according to the second embodiment will be described.

在遵照第2實施形態的光學測定方法，將從具有異向性樣品所測定的反射率光譜做傅立葉轉換而得的功率譜的波峰之中，去除來自並非膜厚的測定對象的層的波峰及波峰附近的資訊。進一步，藉由將去除波峰及波峰附近的資訊之後的功率譜做逆傅立葉轉換，算出去除來自測定對象外的層的資訊的反射率光譜(以下，亦稱為「雜訊去除反射率光譜」。)。對所算出的雜訊去除反射率光譜，與遵照第1實施形態的光學測定方法同樣，藉由適用去除低頻波成分的影響的處理，能夠算出包含在對象樣品的測定對象層的膜厚。In the optical measurement method according to the second embodiment, among the peaks of the power spectrum obtained by Fourier transforming the reflectance spectrum measured from the anisotropic sample, the peaks and the peaks from the layer that is not the measurement target of the film thickness are removed. Information near the crest. Furthermore, by performing inverse Fourier transform on the power spectrum after removing the information from the peak and the vicinity of the peak, the reflectance spectrum (hereinafter, also referred to as "noise removal reflectance spectrum") from which the information from the layer outside the measurement target is removed is calculated. ). With respect to the calculated noise removal reflectance spectrum, as in the optical measurement method according to the first embodiment, the film thickness of the measurement target layer included in the target sample can be calculated by applying processing to remove the influence of low-frequency components.

(d2： 處理程序) 接著，說明關於遵照第2實施形態的光學測定方法的處理程序。(d2: processing procedure) Next, the processing procedure regarding the optical measurement method according to the second embodiment will be described.

圖12係表示遵照第2實施形態的光學測定方法的程序的流程圖。圖12所示主要步驟，典型上可藉由處理裝置100的處理器102將測定程式114(均參照圖3)展開到主記憶體104執行而實現。再者，在圖12的流程圖，關於與圖8的流程圖所示的處理，實質上相同的處理，賦予相同的步驟編號。Fig. 12 is a flowchart showing a procedure of the optical measurement method according to the second embodiment. The main steps shown in FIG. 12 are typically implemented by the processor 102 of the processing device 100 expanding the measurement program 114 (all refer to FIG. 3) to the main memory 104 for execution. In addition, in the flowchart of FIG. 12, regarding the processing shown in the flowchart of FIG. 8, substantially the same processing is given the same step number.

參照圖12，首先，準備光學測定系統1(步驟S1)。在步驟S1，執行包含在光學測定系統1的Y型光纖4的照射口的對位，或分光檢測器20的校正處理等。然後，在光學測定系統1的既定位置配置測定對象的樣品2(步驟S2)。Referring to Fig. 12, first, the optical measurement system 1 is prepared (step S1). In step S1, the alignment of the irradiation port of the Y-type optical fiber 4 included in the optical measurement system 1, the calibration processing of the spectroscopic detector 20, and the like are executed. Then, the sample 2 to be measured is arranged at a predetermined position of the optical measurement system 1 (step S2).

接著，從光源10對樣品2照射測定光，根據分光檢測器20感應樣品2藉由該測定分光所產生的反射光或穿透光所得檢測結果，執行算出光譜的處理。Next, the sample 2 is irradiated with measurement light from the light source 10, and the spectroscopic detector 20 senses the reflected light or transmitted light of the sample 2 by the measurement spectroscopy to perform the process of calculating the spectrum.

在第2實施形態，作為算出光譜的處理，執行從根據分光檢測器20的檢測結果算出樣品2的反射率光譜，算出去除來自包含在樣品2的測定對象外的層的資訊的反射率光譜(雜訊去除反射率光譜)的處理(步驟S3、S11、S12、S13、S14)。In the second embodiment, as the process of calculating the spectrum, the reflectance spectrum of the sample 2 is calculated from the detection result of the spectroscopic detector 20, and the reflectance spectrum ( Noise removal (reflectance spectrum) processing (steps S3, S11, S12, S13, S14).

更具體而言，藉由分光檢測器20感應，對樣品2照射來自光源10的測定光所產生的反射光，測定反射率光譜(步驟S3)。根據分光檢測器20的檢測結果算出樣品2的反射率光譜的處理，可以分光檢測器20執行，亦可以處理裝置100執行。在步驟S3所測定的反射率光譜，作為檢測結果116(參照圖3)，儲藏在處理裝置100的儲存裝置110。More specifically, the sample 2 is irradiated with the reflected light from the measurement light from the light source 10 by the spectroscopic detector 20 to measure the reflectance spectrum (step S3). The processing of calculating the reflectance spectrum of the sample 2 based on the detection result of the spectroscopic detector 20 may be executed by the spectroscopic detector 20 or the processing device 100. The reflectance spectrum measured in step S3 is stored in the storage device 110 of the processing device 100 as the detection result 116 (see FIG. 3).

首先，處理裝置100，藉由將從樣品2所測定的反射率光譜做傅立葉轉換算出功率譜(步驟S11)。然後，處理裝置100，標定包含在所算出的功率譜的並非來自膜厚測定對象的層的波峰(步驟S12)。即，處理裝置100，標定功率譜之中，來自包含在樣品2的測定對象外的層的波峰。First, the processing device 100 calculates a power spectrum by Fourier transforming the reflectance spectrum measured from the sample 2 (step S11). Then, the processing device 100 calibrates the peaks of the layers included in the calculated power spectrum that are not the target of the film thickness measurement (step S12). In other words, the processing device 100 calibrates the power spectrum with peaks from layers outside the measurement target included in the sample 2.

再者，處理裝置100，去除標定的波峰及該波峰附近的資訊(步驟S13)。即，處理裝置100，算出從功率譜去除標定的波峰及該波峰附近的資訊的功率譜(雜訊去除功率譜)。Furthermore, the processing device 100 removes the calibrated peak and the information near the peak (step S13). That is, the processing device 100 calculates a power spectrum (noise removal power spectrum) obtained by removing the calibrated peak and the information near the peak from the power spectrum.

最終，處理裝置100，藉由將去除波峰及波峰附近的資訊後的功率譜做逆傅立葉轉換算出雜訊去除反射率光譜(步驟S14)。Finally, the processing device 100 calculates the noise-removed reflectance spectrum by performing inverse Fourier transform on the power spectrum after removing the peaks and information near the peaks (step S14).

接著，處理裝置100，執行在算出的雜訊去除反射率光譜，標定關於波長的振幅變化滿足既定條件的區段的處理。更具體而言，處理裝置100，標定包含在所算出的雜訊去除反射率光譜中的低頻波成分的底段，去除該標定的底段資訊(步驟S4A)。步驟S4A的處理，在去除對象的光譜不同的點，與圖8所示步驟S4的處理不同，惟處理內容本身與第1實施形態實質上相同。Next, the processing device 100 executes a process of calibrating a section in which the amplitude change with respect to the wavelength satisfies a predetermined condition on the calculated noise removal reflectance spectrum. More specifically, the processing device 100 calibrates the bottom band of the low-frequency component included in the calculated noise removal reflectance spectrum, and removes the calibrated bottom band information (step S4A). The processing of step S4A is different from the processing of step S4 shown in FIG. 8 at the point where the spectrum of the removal target is different, but the processing content itself is substantially the same as that of the first embodiment.

然後，處理裝置100，係使用從算出的光譜去除標定區段的資訊後的光譜執行算出樣品2的光學特性的處理。Then, the processing device 100 executes the process of calculating the optical characteristics of the sample 2 using the spectrum obtained by removing the information of the calibration section from the calculated spectrum.

更具體而言，處理裝置100，係將去除底段資訊的反射率光譜做傅立葉轉換算出功率譜(步驟S5)。再者，處理裝置100，搜尋包含在步驟S5所算出的功率譜的波峰(步驟S6)，根據所搜尋的波峰在功率譜上的位置，算出樣品2的膜厚(步驟S7)。然後，結束光學測定的處理。More specifically, the processing device 100 performs Fourier transform on the reflectance spectrum from which the bottom segment information is removed to calculate the power spectrum (step S5). Furthermore, the processing device 100 searches for a peak including the power spectrum calculated in step S5 (step S6), and calculates the film thickness of the sample 2 based on the position of the searched peak on the power spectrum (step S7). Then, the optical measurement process ends.

再者，將樣品2的膜厚持續測定數次，或需要將樣品2的膜厚測定複數處時，將包含步驟S11~S14的步驟的S3~S7的處理重複執行所需次數。Furthermore, when the film thickness of the sample 2 is continuously measured several times, or when the film thickness of the sample 2 needs to be measured in multiple places, the processing of S3 to S7 including steps S11 to S14 is repeated the required number of times.

(d3： 測定例) 接著，說明關於遵照第2實施形態的光學測定方法的測定例。(d3: Measurement example) Next, a measurement example in accordance with the optical measurement method of the second embodiment will be described.

圖13係表示作為測定對象的樣品2的結構例的示意圖。參照圖13，作為測定對象的樣品2，具有在基板上配置塗層，在塗層上配置覆蓋層的構成。典型上塗層及覆蓋層係由任意的樹脂構成。Fig. 13 is a schematic diagram showing a configuration example of a sample 2 as a measurement target. Referring to Fig. 13, Sample 2 as a measurement target has a configuration in which a coating is arranged on a substrate and a covering layer is arranged on the coating. The top coat and cover layer are typically composed of any resin.

如圖13所示，測定對象為基板的層，塗層及覆蓋層的膜厚為測定對象外。As shown in FIG. 13, the measurement object is the layer of the substrate, and the film thickness of the coating layer and the covering layer are outside the measurement object.

圖14係示根據遵照第2實施形態的光學測定方法的測定例的圖。在圖14(A)表示從圖13所示樣品2所測定的反射率光譜的一例。在圖14(A)所示反射率光譜，無法明顯的確認出現在單層膜的樣品所測定的反射率光譜(例如，參照圖9(A))的「起伏」。惟，並不是不存在「起伏」，而是受到來自其他層的影響，而隱藏了「起伏」的影響的狀態。Fig. 14 is a diagram showing a measurement example according to the optical measurement method according to the second embodiment. Fig. 14(A) shows an example of the reflectance spectrum measured from the sample 2 shown in Fig. 13. In the reflectance spectrum shown in FIG. 14(A), it is impossible to clearly confirm the "fluctuations" in the measured reflectance spectrum (for example, refer to FIG. 9(A)) that appeared on the sample of the single-layer film. However, it is not that there is no "ups and downs", but the state of being affected by other layers, and the influence of "ups and downs" is hidden.

在圖14(B)表示藉由將圖14(A)所示反射率光譜做傅立葉轉換而得的功率譜一例。在圖14(B)所示功率譜，出現對應包含在樣品2的各層的波峰。標定來自包含在該算出的功率譜的並非膜厚測定對象的層(在圖13所示樣品為覆蓋層)的波峰。如圖14(B)所示，對應覆蓋層的波峰具有最大的功率。然後，從功率譜去除標定的波峰及波峰附近的資訊。Fig. 14(B) shows an example of a power spectrum obtained by Fourier transforming the reflectance spectrum shown in Fig. 14(A). In the power spectrum shown in FIG. 14(B), peaks corresponding to the layers included in sample 2 appear. The peaks derived from the layer that is not the target of the film thickness measurement included in the calculated power spectrum (the sample shown in FIG. 13 is the cover layer) are calibrated. As shown in Fig. 14(B), the peak corresponding to the covering layer has the maximum power. Then, remove the calibrated peak and the information near the peak from the power spectrum.

通常，樣品2的構造為已知，可預先決定包含在樣品2中的各層是否為測定對象。此外，由於並非測定對象的層的膜厚亦為已知，故關於在功率譜的任一位置會出現波峰，可預先設定作為條件。因此，在功率譜標定來自並非膜厚測定對象的層的波峰的處理，可藉由使用事先資訊，機械性執行。Generally, the structure of the sample 2 is known, and it can be determined in advance whether each layer included in the sample 2 is a measurement target. In addition, since the film thickness of the layer not to be measured is also known, it is possible to set a condition in advance regarding the appearance of a peak in any position of the power spectrum. Therefore, the processing of calibrating the peaks from the layer that is not the target of film thickness measurement in the power spectrum can be performed mechanically by using prior information.

在圖14所示的例子，測定對象為基板的層，惟關於對應測定對象的基板與相接的塗層資訊，由於需要算出測定對象的膜厚，故並不會被當作去除對象。In the example shown in FIG. 14, the measurement target is the layer of the substrate. However, since the coating information of the substrate corresponding to the measurement target and the coating layer adjacent to the measurement target needs to be calculated, it is not regarded as the removal target.

如圖14(B)所示，關於被去除的波峰以外的波峰，可知在近接的位置發生兩個波峰。即，意指在測定的反射率光譜，發生「起伏」。As shown in FIG. 14(B), regarding the peaks other than the removed peaks, it can be seen that two peaks occur at close positions. That is, it means that "fluctuations" occur in the measured reflectance spectrum.

在圖14(C)表示藉由將去除波峰及波峰附近的資訊後的功率譜做逆傅立葉轉換所算出的雜訊去除反射率光譜的一例。說明的權宜上，在圖14(C)，橫軸為波數(=波長的倒數)。藉由將橫軸以波數表現，可明顯的確認包含在反射率光譜的「起伏」。FIG. 14(C) shows an example of the noise removal reflectance spectrum calculated by performing inverse Fourier transform on the power spectrum after removing the peak and information near the peak. For expediency, in Figure 14(C), the horizontal axis is the wave number (= the inverse of the wavelength). By expressing the horizontal axis as a wave number, it can be clearly confirmed that the "fluctuations" contained in the reflectance spectrum are included.

在圖14(D)表示，對圖14(C)所示雜訊去除反射率光譜，適用遵照第1實施形態的光學測定方法所算出的去除底段資訊的反射率光譜的一例。再者，由於基板及塗層的光學膜厚接近，故在圖14(D)所示反射率光譜，在近接位置發生2個波峰(「基板」及「塗層」)，惟這個並非起因於「起伏」。FIG. 14(D) shows an example in which the noise removal reflectance spectrum shown in FIG. 14(C) is applied to the reflectance spectrum obtained by the optical measurement method according to the first embodiment with the bottom band information removed. Furthermore, since the optical film thickness of the substrate and the coating are close, in the reflectance spectrum shown in Figure 14(D), two peaks ("substrate" and "coating") occur at close positions, but this is not caused by "ups and downs".

如圖14(D)所示，從雜訊去除反射率光譜去除底段資訊之後，藉由再次做傅立葉轉換，可知可抑制發生近接的波峰，藉此可防止測定精度的下降。As shown in Figure 14(D), after removing the bottom band information from the noise removal reflectance spectrum, the Fourier transform is performed again to suppress the occurrence of close peaks, thereby preventing the decrease in measurement accuracy.

(d4： 優點) 根據遵照第2實施形態的光學測定方法，在從樣品所測定的反射率光譜等的光譜做傅立葉轉換的結果，去除來自測定對象外的層的資訊，以此復原成對應原本的光譜的光譜之後，算出樣品的光學特性。與遵照上述第1實施形態的光學測定方法一樣，由於可去除出現在復原光譜的起伏(因不同頻率成分所組合的變動)的影響，故可抑制測定精度的下降。(d4: advantages) According to the optical measurement method in accordance with the second embodiment, after Fourier transform results from the measured reflectance spectrum and other spectra of the sample, the information from the layer outside the measurement target is removed to restore the spectrum corresponding to the original spectrum , Calculate the optical properties of the sample. Like the optical measurement method according to the first embodiment described above, since the influence of fluctuations (variations due to a combination of different frequency components) appearing in the restored spectrum can be removed, the decrease in measurement accuracy can be suppressed.

>E. 總結> 根據上述發明的詳細說明，應可理解使用本案發明者們所發現的光干涉法的光學測定方法所發生的新課題、及對該課題的解決手段的有效性。 雖然說明了關於本發明的實施形態，惟本次所揭示的實施形態在所有的點僅為例示，不應認為是限制性。本發明的範圍係以申請範圍揭示，包含與申請範圍均等的意思及範圍內的所有變更。>E. Summary> Based on the detailed description of the above-mentioned invention, it should be understood that the new problem that occurs in the optical measurement method using the optical interferometry discovered by the inventors of the present application and the effectiveness of the solution to the problem. Although the embodiments of the present invention have been described, the embodiments disclosed this time are merely examples in all points and should not be considered restrictive. The scope of the present invention is disclosed in the scope of application, and includes the meaning equivalent to the scope of application and all changes within the scope.

1:光學測定系統 2:樣品 4:Y型光纖 10:光源 20:分光檢測器 22:繞射光柵 24:受光部 26:界面電路 30:評價窗 32:底段 100:處理裝置 102:處理器 104:主記憶體 106:輸入部 108:顯示部 110:儲存裝置 112:作業系統 114:測定程式 116:檢測結果 118:測定結果 120:通訊界面 122:網路界面 124:媒體驅動器 126:記錄媒體1: Optical measurement system 2: sample 4: Y-type fiber 10: light source 20: Spectroscopic detector 22: Diffraction grating 24: Light receiving part 26: Interface circuit 30: Evaluation window 32: bottom section 100: processing device 102: processor 104: main memory 106: Input section 108: Display 110: storage device 112: Operating System 114: Measurement program 116: test result 118: Measurement result 120: Communication interface 122: network interface 124: Media Drive 126: recording media

S1~S7:步驟 S1~S7: steps

Claims (11)

一種光學測定系統，其具備： 光源，其係用於產生照射樣品的測定光； 分光檢測器，其係用於感應上述樣品藉由上述測定光所產生的反射光或穿透光；及 處理裝置，其係用於輸入上述分光檢測器的檢測結果， 上述處理裝置，構成為可執行： 根據上述分光檢測器的檢測結果算出第1光譜的處理； 標定在上述第1光譜，關於波長的振幅變化滿足既定條件的區段的處理； 使用從上述第1光譜去除上述標定區段資訊的第2光譜算出上述樣品的光學特性的處理。An optical measurement system, which has: Light source, which is used to generate measurement light that illuminates the sample; Spectroscopic detector, which is used to sense the reflected light or transmitted light generated by the above-mentioned sample by the above-mentioned measuring light; and The processing device is used to input the detection result of the above-mentioned spectroscopic detector, The above processing device is configured to be executable: The process of calculating the first spectrum based on the detection result of the above-mentioned spectroscopic detector; Calibration in the above-mentioned first spectrum, the processing of the section where the amplitude change of the wavelength meets the established conditions; A process of calculating the optical characteristics of the sample using a second spectrum obtained by subtracting the calibration zone information from the first spectrum. 如申請專利範圍第1項所述之光學測定系統，其中上述標定的處理，包含： 對上述第1光譜，依序設定具有預先決定的波長寬幅的評價窗的處理； 根據包含在各評價窗的上述第1光譜的振幅的變化，判斷對應各評價窗的區段是否滿足上述既定條件的處理。The optical measurement system described in item 1 of the scope of patent application, wherein the above-mentioned calibration processing includes: For the above-mentioned first spectrum, the process of sequentially setting an evaluation window with a predetermined wavelength width; Based on the change in the amplitude of the first spectrum included in each evaluation window, it is a process of judging whether the segment corresponding to each evaluation window satisfies the above-mentioned predetermined condition. 如申請專利範圍第2項所述之光學測定系統，其中判斷對應各評價窗的區段是否滿足上述既定條件的處理，包含：算出在對應上述第1光譜的各評價窗的區段的振幅的誤差程度的處理。The optical measurement system described in the second item of the scope of patent application, wherein the process of judging whether the section corresponding to each evaluation window meets the above-mentioned predetermined condition includes: calculating the amplitude of the section corresponding to each evaluation window of the first spectrum The degree of error handling. 如申請專利範圍第3項所述之光學測定系統，其中在對應上述第1光譜的各評價窗的區段的振幅的誤差程度低於上述既定限值時，可判斷對應該評價窗的區段滿足上述既定條件。The optical measurement system described in item 3 of the scope of patent application, wherein when the error degree of the amplitude of each evaluation window segment corresponding to the first spectrum is lower than the predetermined limit, the segment corresponding to the evaluation window can be determined Meet the established conditions above. 如申請專利範圍第2項所述之光學測定系統，其中上述評價窗的波長寬幅，對每一樣品種類預先設定。In the optical measurement system described in item 2 of the scope of patent application, the wavelength width of the above-mentioned evaluation window is preset for each sample type. 如申請專利範圍第1至5項之任何一項所述之光學測定系統，其中算出上述樣品光學特性的處理，包含：根據對上述第2光譜做傅立葉轉換的結果所出現的波峰算出膜厚的處理。The optical measurement system described in any one of items 1 to 5 in the scope of the patent application, wherein the processing for calculating the optical characteristics of the sample includes: calculating the film thickness based on the peaks appearing as a result of Fourier transform of the second spectrum deal with. 如申請專利範圍第1至5項之任何一項所述之光學測定系統，其中算出上述第1光譜的處理，亦可包含：作為上述第1光譜，根據分光檢測器的檢測結果算出上述樣品反射率光譜的處理。The optical measurement system described in any one of items 1 to 5 in the scope of the patent application, wherein the process of calculating the first spectrum may also include: as the first spectrum, calculating the reflection of the sample based on the detection result of the spectroscopic detector Rate spectrum processing. 如申請專利範圍第1至5項之任何一項所述之光學測定系統，其中算出上述第1光譜的處理，亦可包含：作為上述第1光譜，從根據分光檢測器的檢測結果算出上述樣品的反射率光譜，算出去除來自包含在上述樣品的測定對象外的層的資訊的反射率光譜的處理。The optical measurement system described in any one of items 1 to 5 in the scope of the patent application, wherein the process of calculating the first spectrum may also include: as the first spectrum, calculating the sample from the detection result of the spectroscopic detector The process of calculating the reflectance spectrum of the above sample by removing the information from the layer outside the measurement target of the sample. 如申請專利範圍第8項所述之光學測定系統，其中算出上述第1光譜的處理，進一步包含： 將上述樣品的反射率光譜做傅立葉轉換算出第3光譜的處理； 標定上述第3光譜之中，來自包含在上述樣品中的測定對象外的層的波峰的處理；及 將該標定的波峰及該波峰附近的資訊從上述第3光譜去除算出第4光譜的處理。The optical measurement system described in item 8 of the scope of patent application, wherein the processing for calculating the first spectrum described above further includes: The reflectance spectrum of the above sample is processed by Fourier transform to calculate the third spectrum; Processing of calibrating the peaks of the third spectrum from the layer outside the measurement object contained in the sample; and The processing of calculating the fourth spectrum by removing the calibrated peak and the information near the peak from the third spectrum. 如申請專利範圍第9項所述之光學測定系統，其中算出上述第1光譜的處理，進一步包含：將上述第4光譜做逆傅立葉轉換算出上述第1光譜的處理。The optical measurement system described in claim 9, wherein the process of calculating the first spectrum further includes the process of calculating the first spectrum by performing inverse Fourier transform on the fourth spectrum. 一種光學測定方法，其具備： 從光源對樣品照射測定光，根據分光檢測器感應上述樣品藉由該測定光所產生的反射光或穿透光所得檢測結果，算出第1光譜的步驟； 標定在上述第1光譜，關於波長的振幅變化滿足既定條件的區段的步驟； 使用從上述第1光譜去除上述標定區段資訊的第2光譜算出上述樣品的光學特性步驟。An optical measurement method, which has: The step of irradiating the sample with measurement light from the light source, and calculating the first spectrum based on the detection result obtained by the spectroscopic detector sensing the reflected light or transmitted light generated by the measurement light of the sample; Steps to calibrate in the above-mentioned first spectrum, with respect to the section where the amplitude change of the wavelength meets the established conditions; A step of calculating the optical characteristics of the sample using a second spectrum obtained by subtracting the calibration zone information from the first spectrum.
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