CN117109455A - Film thickness measurement device and method - Google Patents

Film thickness measurement device and method Download PDF

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CN117109455A
CN117109455A CN202311221203.9A CN202311221203A CN117109455A CN 117109455 A CN117109455 A CN 117109455A CN 202311221203 A CN202311221203 A CN 202311221203A CN 117109455 A CN117109455 A CN 117109455A
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sample
light
film thickness
ellipsometry
measurement
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孙伟
金尚忠
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China Jiliang University
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01BMEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00Measuring arrangements characterised by the use of optical techniques
    • G01B11/02Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/06Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material

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Abstract

The application provides a film thickness measuring device, which comprises a sample stage, wherein the film thickness measuring device further comprises: the emission end is used for emitting incident light to a sample on the sample table, the incident light is formed by converging four lasers with different wavelengths, and the emission end can adjust the incident light into linearly polarized light; the receiving end is used for receiving emergent light formed by sample reflection, comprises a polarization detection component and a detection component, realizes detection of emergent light intensity under different azimuth angles by adjusting the polarization detection component, and obtains a group of light intensity values corresponding to the wavelengths of four lasers under each azimuth angle; and the processing component is used for respectively adopting an ellipsometry calculation method and a spectroscopic measurement calculation method according to the azimuth angle and the light intensity value to obtain the film thickness and the optical parameters of the sample, and comparing the film thicknesses calculated by the ellipsometry calculation method and the spectroscopic measurement calculation method to determine the film thickness value of the sample. The measuring device provided by the application can completely cover the measuring range of the film thickness.

Description

薄膜厚度测量装置及方法Film thickness measurement device and method

技术领域Technical field

本申请涉及光学测量技术领域,尤其涉及一种薄膜厚度测量装置及方法。The present application relates to the field of optical measurement technology, and in particular to a film thickness measurement device and method.

背景技术Background technique

光学薄膜的检测主要由两个方面构成,薄膜厚度和光学常数;在实际的生产制备中,还需要对薄膜的厚度分布的均匀性进行检测。在薄膜厚度和光学常数的测量中,椭偏测量和光谱测量是目前使用最为广泛的技术,但是两者在薄膜厚度的测量范围和精度不同,目前针对不同的薄膜厚度需要采用不同的方法进行测量,测量步骤较为复杂。The detection of optical films mainly consists of two aspects, film thickness and optical constants; in actual production preparation, the uniformity of the thickness distribution of the film also needs to be detected. In the measurement of film thickness and optical constants, ellipsometry and spectrometry are currently the most widely used technologies. However, they have different measurement ranges and accuracy of film thickness. Currently, different methods need to be used to measure different film thicknesses. , the measurement steps are more complicated.

在相关技术中,光谱测量多采用分光光度计,通过分光光度计测量得出薄膜的反射(或透射)光谱,进而计算薄膜的反射率和透过率,并计算薄膜的厚度和光学常数。椭偏测量则可以采用激光、LED灯、卤素灯等作为光源,通过调制入射到薄膜的和经由薄膜反射的偏振光,对薄膜的厚度和光学常数进行测量。其中光谱测量的测量范围较大,但是测量几百纳米薄膜的测量精度较差,无法满足测量需求;而对于椭偏测量来说,由于薄膜厚度的周期性问题,无法对多个周期厚度的薄膜进行测量,会存在多解的问题,虽然目前也有采用穆勒矩阵的宽光谱薄膜厚度测量装置,但是需要对每一个器件进行定标,同时安装等误差会对测量结果产生较大的影响。In related technologies, spectrophotometers are often used for spectral measurement. The reflection (or transmission) spectrum of the film is measured by the spectrophotometer, and then the reflectivity and transmittance of the film are calculated, as well as the thickness and optical constants of the film. Ellipsometry measurement can use lasers, LED lamps, halogen lamps, etc. as light sources to measure the thickness and optical constants of the film by modulating the polarized light incident on the film and reflected by the film. Among them, the measurement range of spectral measurement is relatively large, but the measurement accuracy of measuring films of several hundred nanometers is poor and cannot meet the measurement needs; and for ellipsometry, due to the periodicity problem of film thickness, it is impossible to measure films with multiple periodic thicknesses. There will be multiple solutions to the problem of measurement. Although there are currently wide-spectrum film thickness measurement devices using Mueller matrices, each device needs to be calibrated, and errors such as installation will have a greater impact on the measurement results.

因此,有必要提出一种技术方案,解决相关技术中薄膜厚度测量方法测量薄膜厚度时测量范围受限的问题。Therefore, it is necessary to propose a technical solution to solve the problem of limited measurement range when measuring film thickness using film thickness measurement methods in related technologies.

发明内容Contents of the invention

本申请的目的在于提出一种技术方案,解决相关技术中薄膜厚度测量方法测量薄膜厚度时测量范围受限的问题。The purpose of this application is to propose a technical solution to solve the problem of limited measurement range when measuring film thickness using film thickness measurement methods in related technologies.

基于以上问题,本申请提供一种薄膜厚度测量装置,包括样品台,样品台用于承载样品,薄膜厚度测量装置用于检测样品的薄膜厚度和光学常数,薄膜厚度测量装置包括:Based on the above problems, this application provides a film thickness measurement device, which includes a sample stage. The sample stage is used to carry the sample. The film thickness measurement device is used to detect the film thickness and optical constants of the sample. The film thickness measurement device includes:

发射端,发射端用于向样品台上的样品发射入射光,入射光由四个波长不同的激光汇合形成,并且,发射端可以将入射光调节为线偏振光;The emission end is used to emit incident light to the sample on the sample stage. The incident light is formed by the convergence of four lasers with different wavelengths, and the emission end can adjust the incident light into linearly polarized light;

接收端,接收端用于接收样品反射形成的出射光,接收端包括检偏组件和探测组件,通过调节检偏组件,实现对不同方位角下出射光强的探测,在每一方位角下,获得一组四个激光的波长对应的光强值;The receiving end is used to receive the outgoing light formed by the reflection of the sample. The receiving end includes an analyzer component and a detection component. By adjusting the analyzer component, the detection of the outgoing light intensity at different azimuth angles is achieved. At each azimuth angle, Obtain the light intensity values corresponding to the wavelengths of a set of four lasers;

处理组件,根据方位角和光强值,分别采用椭偏测量和光谱测量的计算方法,获得样品的薄膜厚度和光学参数,并将两者方法计算得的薄膜厚度进行对比,以确定样品的薄膜厚度取值。The processing component uses the calculation methods of ellipsometry and spectral measurement to obtain the film thickness and optical parameters of the sample based on the azimuth angle and light intensity value, respectively, and compares the film thickness calculated by the two methods to determine the film thickness of the sample. Thickness value.

进一步的,发射端包括:Further, the transmitter includes:

光源组件,包括四个激光发射器,各个激光发射器所发射的激光波长各不相同;The light source assembly includes four laser transmitters, each of which emits laser light with different wavelengths;

分束器组,包括级联的分束器,将各个激光发射器所发射的激光组合成公共光束;A beam splitter group, including a cascade of beam splitters, combines the lasers emitted by each laser transmitter into a common beam;

起偏组件,包括第一偏振器,第一偏振器可旋转方位角,用于将公共光束转换为线偏振光,并将转换为线偏振光的公共光束作为入射光。The polarizing component includes a first polarizer, the first polarizer can rotate the azimuth angle, and is used to convert the common light beam into linearly polarized light, and use the common light beam converted into linearly polarized light as incident light.

进一步的,接收端包括:Further, the receiving end includes:

检偏组件,包括第二偏振器和第三偏振器,入射光经过样品表面反射后形成出射光,出射光依次经过第二偏振器和第三偏振器,第二偏振器和第三偏振器的方位角可调;The analyzer component includes a second polarizer and a third polarizer. The incident light is reflected by the surface of the sample to form outgoing light. The outgoing light passes through the second polarizer and the third polarizer in sequence, and the second polarizer and the third polarizer. Azimuth angle adjustable;

二向色镜组,二向色镜组包括三个二向色镜,各个二向色镜同光轴排列,出射光经过二向色镜时部分反射、部分透射,以将不同波长的光分离;Dichroic mirror group. The dichroic mirror group includes three dichroic mirrors. Each dichroic mirror is arranged on the same optical axis. When the outgoing light passes through the dichroic mirror, it is partially reflected and partially transmitted to separate the light of different wavelengths. ;

探测组件,包括四个探测器,其中三个探测器分别接收各个二向色镜反射的光束,剩余一个探测器接收从最后一个二向色镜透射的光束,探测器用于探测所接收光束的光强。The detection component includes four detectors, three of which receive the light beam reflected by each dichroic mirror respectively, and the remaining one receives the light beam transmitted from the last dichroic mirror. The detector is used to detect the light of the received light beam. powerful.

进一步的,第二偏振器采用磁光调制器件。Further, the second polarizer adopts a magneto-optical modulation device.

进一步的,处理组件通过如下公式计算椭偏参数ψ和Δ:Further, the processing component calculates the ellipsometric parameters ψ and Δ through the following formulas:

2ψ=arccos(-s1/s0)2ψ=arccos(-s 1 /s 0 )

Δ=arccos(s2/s0·sin2ψ)Δ=arccos(s 2 /s 0 ·sin2ψ)

式中,s0、s1、s2表示斯托克斯参量,通过如下公式计算:In the formula, s 0 , s 1 , and s 2 represent Stokes parameters, which are calculated by the following formula:

s0-i=4×(a0-i-a4-i)s 0-i =4×(a 0-i -a 4-i )

式中,a0-i、a2-i、b2-i、a4-i、b4-i为傅里叶系数,通过如下公式计算获得:In the formula, a 0-i , a 2-i , b 2-i , a 4-i , and b 4-i are Fourier coefficients, which are calculated by the following formula:

式中,i表示探测器序号,N表示检测的方位角总数,Ij表示探测器i在第j次检测中获得的光强值,Wj表示第二偏振器在第j次检测中的方位角;In the formula, i represents the detector serial number, N represents the total number of azimuth angles detected, I j represents the light intensity value obtained by detector i in the j-th detection, and W j represents the orientation of the second polarizer in the j-th detection. horn;

处理组件根据椭偏参数ψ和Δ,通过数值反演计算获得样品薄膜厚度的椭偏测量值和对应的光学常数。The processing component obtains the ellipsometric measurement value of the sample film thickness and the corresponding optical constants through numerical inversion calculation based on the ellipsometric parameters ψ and Δ.

进一步的,处理组件还根据S偏振光和P偏振光的光强,计算P光分量和S光分量的总反射系数,P光分量和S光分量的总反射系数通过如下公式表示:Further, the processing component also calculates the total reflection coefficient of the P light component and the S light component based on the light intensity of the S polarized light and P polarized light. The total reflection coefficient of the P light component and the S light component is expressed by the following formula:

其中,r1p,r1s分别为空气/薄膜界面进行一次反射的P分量的反射系数和S分量的反射系数,r2p,r2s分别为薄膜/基片界面上进行一次反射的P分量的反射系数和S分量的反射系数,2δ是相邻反射光光束之间的相位差,通过如下公式表示:Among them, r 1p and r 1s are respectively the reflection coefficient of the P component and the S component that are reflected once at the air/film interface. r 2p and r 2s are the reflection coefficients of the P component that is reflected once at the film/substrate interface. coefficient and the reflection coefficient of the S component, 2δ is the phase difference between adjacent reflected light beams, expressed by the following formula:

式中,而λ为光的波长,n为薄膜的复折射率,为薄膜中的折射角;In the formula, λ is the wavelength of light, n is the complex refractive index of the film, is the refraction angle in the film;

处理组件还根据计算得到的薄膜对四个波长的反射率,计算得出薄膜厚度的光谱测量值和对应的光学常数。The processing component also calculates spectral measurements of film thickness and corresponding optical constants based on the calculated reflectivity of the film at four wavelengths.

进一步的,处理组件根据椭偏测量原理对光强数据进行处理,获得椭偏参数,并根据椭偏参数获得椭偏测量结果,椭偏测量结果包括样品的薄膜厚度的椭偏测量值和对应的光学常数;Further, the processing component processes the light intensity data according to the ellipsometry principle to obtain the ellipsometry parameters, and obtains the ellipsometry measurement results based on the ellipsometry parameters. The ellipsometry measurement results include the ellipsometry measurement value of the film thickness of the sample and the corresponding optical constants;

处理组件还根据光谱测量原理对光强数据进行处理,计算样品薄膜对不同波长光束的反射率,并根据反射率获得光谱测量结果,光谱测量结果包括样品的薄膜厚度的光谱测量值和对应的光学常数;The processing component also processes the light intensity data according to the principle of spectral measurement, calculates the reflectivity of the sample film to light beams of different wavelengths, and obtains spectral measurement results based on the reflectivity. The spectral measurement results include the spectral measurement value of the film thickness of the sample and the corresponding optical constant;

处理组件还将椭偏测量结果与光谱测量结果对比,当椭偏测量值与光谱测量值均在一个厚度周期范围内时,测量结果输出椭偏测量值,若两者的测量结果之间大于一个厚度周期,则输出光谱测量值作为测量结果。The processing component also compares the ellipsometry measurement results with the spectrum measurement results. When the ellipsometry measurement value and the spectrum measurement value are both within a thickness period range, the measurement result outputs the ellipsometry measurement value. If the difference between the two measurement results is greater than one thickness period, the spectrum measurement value is output as the measurement result.

进一步的,样品台包括:Furthermore, the sample stage includes:

载物平面用于承载样品;The loading plane is used to carry the sample;

五维调节平台用于保障待测样品所在平面与入射平面垂直,并调整让载物平面中心与入射光轴重合;The five-dimensional adjustment platform is used to ensure that the plane of the sample to be measured is perpendicular to the incident plane, and is adjusted so that the center of the carrier plane coincides with the incident optical axis;

电动旋转平台带动载物平面旋转,从而使待测样品旋转,实现圆周测量。The electric rotating platform drives the load plane to rotate, thereby rotating the sample to be measured and achieving circumferential measurement.

本申请还提供一种薄膜厚度测量方法,该方法基于如上所述的薄膜厚度测量装置进行,方法包括一下步骤:This application also provides a film thickness measurement method, which is based on the film thickness measurement device as described above. The method includes the following steps:

S1、根据样品上薄膜的折射率范围,设置入射光的入射角度;S1. Set the incident angle of the incident light according to the refractive index range of the film on the sample;

S2、样品台上放置样品基片,并将第一至第三偏振器的偏光轴先后调节至P分量和S分量,调整样品台和接收端,获得合适信号,并记录作为基线;S2. Place the sample substrate on the sample stage, adjust the polarization axes of the first to third polarizers to the P component and S component successively, adjust the sample stage and the receiving end, obtain a suitable signal, and record it as the baseline;

S3、将样品放置在样品台上,样品中心与样品台中心对准;S3. Place the sample on the sample stage and align the center of the sample with the center of the sample stage;

S4、调节第一至第三偏振器,采集光强数据,根据椭偏测量原理对光强数据进行处理,获得椭偏参数,并根据椭偏参数获得椭偏测量结果,椭偏测量结果包括样品的薄膜厚度的椭偏测量值和对应的光学常数;S4. Adjust the first to third polarizers, collect light intensity data, process the light intensity data according to the ellipsometry principle, obtain ellipsometry parameters, and obtain ellipsometry measurement results based on the ellipsometry parameters. The ellipsometry measurement results include the sample Ellipsometric measurement values of film thickness and corresponding optical constants;

S5、调节第一至第三偏振器,采集光强数据,根据光谱测量原理对光强数据进行处理,计算样品薄膜对不同波长光束的反射率,并根据反射率获得光谱测量结果,光谱测量结果包括样品的薄膜厚度的光谱测量值和对应的光学常数;S5. Adjust the first to third polarizers, collect light intensity data, process the light intensity data according to the principle of spectral measurement, calculate the reflectivity of the sample film to light beams of different wavelengths, and obtain the spectral measurement results based on the reflectance. The spectral measurement results Includes spectral measurements of film thickness of the sample and corresponding optical constants;

S6、将椭偏测量结果与光谱测量结果对比,当椭偏测量值与光谱测量值均在一个厚度周期范围内时,输出椭偏测量值作为测量结果,若两者的测量结果之间大于一个厚度周期,则输出光谱测量值作为测量结果。S6. Compare the ellipsometry measurement results with the spectrum measurement results. When the ellipsometry measurement value and the spectrum measurement value are both within a thickness period range, output the ellipsometry measurement value as the measurement result. If the difference between the two measurement results is greater than one thickness period, the spectrum measurement value is output as the measurement result.

进一步的,步骤S4中包括以下步骤:Further, step S4 includes the following steps:

S41、控制第一偏振器的偏光轴与入射光的入射面成45°角,第三偏振器的偏光轴与入射面成0°角;S41. Control the polarization axis of the first polarizer to form an angle of 45° with the incident surface of the incident light, and the polarization axis of the third polarizer to form an angle of 0° with the incident surface;

S42、调节第二偏振器,使得第二偏振器的初始偏光轴位置与入射面成0°角;S42. Adjust the second polarizer so that the initial polarization axis position of the second polarizer forms an angle of 0° with the incident surface;

S43、采用磁光调制改变第二偏振器的方位角,方位角每改变θ,记录一次光强数据;S43. Use magneto-optical modulation to change the azimuth angle of the second polarizer. Every time the azimuth angle changes θ, record the light intensity data;

S44、根据椭偏测量原理对光强数据进行处理,获得椭偏参数,并根据椭偏参数获得样品的薄膜厚度的椭偏测量值和对应的光学常数。S44. Process the light intensity data according to the ellipsometry principle to obtain the ellipsometry parameters, and obtain the ellipsometry measurement value of the film thickness of the sample and the corresponding optical constants based on the ellipsometry parameters.

根据以上说明,本发明将光谱测量与椭偏测量结合,可以完整地覆盖薄膜厚度测量的范围,并可以根据椭偏测量和光谱测量的结果实现自标定,提高了测量精度膜厚。并在载物台的设计中引入自动位移结构,在对一点的厚度测量后,可以根据不同位置处的光强,快速获得薄膜分布情况,判断薄膜均匀性。According to the above description, the present invention combines spectral measurement and ellipsometry, which can completely cover the range of film thickness measurement, and can realize self-calibration based on the results of ellipsometry and spectrum measurement, improving the accuracy of film thickness measurement. An automatic displacement structure is introduced into the design of the stage. After measuring the thickness at a point, the distribution of the film can be quickly obtained based on the light intensity at different positions and the uniformity of the film can be judged.

附图说明Description of drawings

图1为本申请实施例提供的薄膜厚度测量装置示意图;Figure 1 is a schematic diagram of a film thickness measurement device provided by an embodiment of the present application;

图2为本申请实施例提供的薄膜厚度测量装置中发射端和接收端结构示意图;Figure 2 is a schematic structural diagram of the transmitting end and receiving end of the film thickness measuring device provided by the embodiment of the present application;

图3为本申请实施例提供的薄膜厚度测量装置中第二偏振器的结构示意图;Figure 3 is a schematic structural diagram of the second polarizer in the film thickness measuring device provided by the embodiment of the present application;

图4为本申请实施例提供的样品台示意图;Figure 4 is a schematic diagram of the sample stage provided by the embodiment of the present application;

图5为本申请实施例提供的薄膜厚度测量方法流程图。Figure 5 is a flow chart of a film thickness measurement method provided by an embodiment of the present application.

薄膜厚度测量装置100,样品台11,发射端12,接收端13,处理组件14,载物平面111,五维调节平台112,电动旋转平台113,电动X轴位移平台114,光源组件121,分束器组122,起偏组件123,检偏组件131,二向色镜组132,探测组件133,第一偏振器1231,第二偏振器1311,第三偏振器1312,磁光晶体1311a,控制器1311b。Film thickness measuring device 100, sample stage 11, transmitting end 12, receiving end 13, processing component 14, load plane 111, five-dimensional adjustment platform 112, electric rotation platform 113, electric X-axis displacement platform 114, light source assembly 121, minute Beam set 122, polarizing component 123, analyzer component 131, dichroic mirror group 132, detection component 133, first polarizer 1231, second polarizer 1311, third polarizer 1312, magneto-optical crystal 1311a, control Device 1311b.

具体实施方式Detailed ways

以下将结合附图所示的具体实施方式对本申请进行详细描述,但这些实施方式并不限制本申请,本领域的普通技术人员根据这些实施方式所做出的结构、方法、或功能上的变换均包含在本申请的保护范围内。The present application will be described in detail below with reference to the specific embodiments shown in the drawings. However, these embodiments do not limit the present application. Those of ordinary skill in the art may make structural, method, or functional changes based on these embodiments. are included in the protection scope of this application.

如图1所示,本申请提供一种薄膜厚度测量装置100,包括样品台11,样品台11用于承载样品,薄膜厚度测量装置100用于检测样品的薄膜厚度和光学常数。薄膜厚度测量装置100还包括:As shown in Figure 1, this application provides a film thickness measurement device 100, which includes a sample stage 11. The sample stage 11 is used to carry a sample, and the film thickness measurement device 100 is used to detect the film thickness and optical constants of the sample. The film thickness measuring device 100 also includes:

发射端12,所述发射端12用于向所述样品台11上的样品发射入射光,所述入射光由四个波长不同的激光汇合形成,并且,所述发射端12可以将所述入射光调节为线偏振光;Emitting end 12. The emitting end 12 is used to emit incident light to the sample on the sample stage 11. The incident light is formed by the convergence of four lasers with different wavelengths, and the emitting end 12 can transmit the incident light. The light is adjusted to linearly polarized light;

接收端13,所述接收端13用于接收所述样品反射形成的出射光,所述接收端13包括检偏组件131和探测组件133,通过调节所述检偏组件131,实现对不同方位角下出射光强的探测,在每一方位角下,获得一组四个所述激光的波长对应的光强值;Receiving end 13. The receiving end 13 is used to receive the outgoing light formed by reflection of the sample. The receiving end 13 includes an analyzer component 131 and a detection component 133. By adjusting the analyzer component 131, it is possible to detect different azimuth angles. Detect the outgoing light intensity, and obtain a set of four light intensity values corresponding to the wavelengths of the laser at each azimuth angle;

处理组件14,根据所述方位角和所述光强值,分别采用椭偏测量和光谱测量的计算方法,获得所述样品的薄膜厚度和光学参数,并将两者方法计算得的薄膜厚度进行对比,以确定样品的薄膜厚度取值。The processing component 14, according to the azimuth angle and the light intensity value, uses the calculation methods of ellipsometry and spectral measurement respectively to obtain the film thickness and optical parameters of the sample, and calculates the film thickness calculated by the two methods. Compare to determine the film thickness value of the sample.

根据以上说明,本申请实施例提供一种将椭偏测量和光谱测量相结合的薄膜测量装置。利用本申请实施例提供的装置,可以在同一时间同时对椭偏测量和光谱测量两种测量方式所需的参数进行测量,确保两者测量方式所采用的计算参数是在同等条件下测量获得,从而可以通过将椭偏测量和光谱测量的计算结果进行对比,可以自动判断薄膜厚度范围,对测量结果进行自主验证,从而可以解决椭偏测量对多个周期厚度的薄膜进行测量会存在多解的问题,利用本申请提供的薄膜厚度测量装置100,可以完整地覆盖薄膜厚度测量的范围,并可以根据椭偏测量和光谱测量的结果实现自标定,提高了测量精度膜厚。According to the above description, embodiments of the present application provide a thin film measurement device that combines ellipsometry and spectrum measurement. Using the device provided by the embodiment of the present application, the parameters required for the two measurement methods of ellipsometry and spectrum measurement can be measured at the same time, ensuring that the calculation parameters used in the two measurement methods are measured under the same conditions. Therefore, by comparing the calculation results of ellipsometry and spectral measurement, the film thickness range can be automatically determined and the measurement results can be independently verified, thereby solving the problem of multiple solutions when ellipsometry measures films with multiple periodic thicknesses. To solve the problem, the film thickness measurement device 100 provided by the present application can completely cover the range of film thickness measurement, and can realize self-calibration based on the results of ellipsometry and spectrum measurement, thereby improving the accuracy of film thickness measurement.

如图2所示,作为一种可选的实现方式,发射端12包括光源组件121、分束器组122以及起偏组件123。As shown in FIG. 2 , as an optional implementation manner, the emission end 12 includes a light source component 121 , a beam splitter group 122 and a polarizing component 123 .

其中,光源组件121包括四个激光发射器,各个激光发射器所发射的激光波长各不相同。本申请实施例提供的薄膜厚度测量装置100采用激光作为光源,具有良好的准直特性,不必采用透镜等结构,减少色散对检测的影响,提高了检测精度。The light source component 121 includes four laser emitters, and the laser wavelengths emitted by each laser emitter are different. The film thickness measurement device 100 provided in the embodiment of the present application uses laser as the light source, has good collimation characteristics, does not need to use structures such as lenses, reduces the impact of dispersion on detection, and improves detection accuracy.

分束器组122包括级联的分束器,将各个激光发射器所发射的激光组合成公共光束。The beam splitter group 122 includes cascaded beam splitters that combine the lasers emitted by the individual laser emitters into a common beam.

起偏组件123包括第一偏振器1231,第一偏振器1231可旋转方位角,用于将公共光束转换为线偏振光,线偏振光作为入射光照射在样品表面。The polarizing component 123 includes a first polarizer 1231. The first polarizer 1231 can rotate the azimuth angle and is used to convert the common light beam into linearly polarized light. The linearly polarized light is irradiated on the surface of the sample as incident light.

作为一种可选的实现方式,接收端13包括检偏组件131、二向色镜组132和探测组件133。As an optional implementation, the receiving end 13 includes an analysis component 131 , a dichroic mirror group 132 and a detection component 133 .

其中,检偏组件131包括第二偏振器1311和第三偏振器1312,入射光经过样品表面反射后形成出射光,出射光依次经过第二偏振器1311和第三偏振器1312,第二偏振器1311和第三偏振器1312的方位角可调;Among them, the analyzer component 131 includes a second polarizer 1311 and a third polarizer 1312. The incident light is reflected by the sample surface to form outgoing light. The outgoing light passes through the second polarizer 1311 and the third polarizer 1312 in sequence. The second polarizer The azimuth angles of 1311 and the third polarizer 1312 are adjustable;

二向色镜组132包括三个二向色镜,各个二向色镜同光轴排列,出射光经过二向色镜时部分反射、部分透射,以将不同波长的光分离;The dichroic mirror group 132 includes three dichroic mirrors. Each dichroic mirror is arranged on the same optical axis. When the emitted light passes through the dichroic mirror, it is partially reflected and partially transmitted to separate the light of different wavelengths;

探测组件133包括四个探测器,其中三个探测器分别接收各个二向色镜反射的光束,剩余一个探测器接收从最后一个二向色镜透射的光束,探测器用于探测所接收光束的光强。The detection component 133 includes four detectors, three of which receive the light beam reflected by each dichroic mirror respectively, and the remaining one receives the light beam transmitted from the last dichroic mirror, and the detector is used to detect the light of the received light beam. powerful.

处理组件14可以根据方位角和光强值,分别采用椭偏测量和光谱测量的计算方法,获得样品的薄膜厚度和光学参数,并将两者方法计算得的薄膜厚度进行对比,以确定样品的薄膜厚度取值以及所述薄膜厚度取值所对应的所述光学参数。The processing component 14 can obtain the film thickness and optical parameters of the sample using calculation methods of ellipsometry and spectrum measurement respectively based on the azimuth angle and light intensity value, and compare the film thickness calculated by the two methods to determine the thickness of the sample. The film thickness value and the optical parameter corresponding to the film thickness value.

具体的,对于椭偏测量,通过同一光谱对反射光的偏振态变化进行测量,如果已知偏振方向的线偏振光从样品表面反射,则反射光会变成椭圆偏振光,椭圆偏振光的偏振态取决于入射角、线偏振光的入射方向以及样品表面的反射特性,可以在椭圆偏振测量中确定两个椭偏参数ψ和Δ,利用椭偏参数ψ和Δ获得材料的光学常数和样品的薄膜厚度。其中,对于椭偏参数ψ,tanψ表示p光与s光反射后振幅的比值,Δ则表示p光与s光相位差的变化量。Specifically, for ellipsometry, the change in polarization state of the reflected light is measured through the same spectrum. If linearly polarized light with a known polarization direction is reflected from the sample surface, the reflected light will become elliptically polarized light. The polarization of the elliptically polarized light The state depends on the incident angle, the incident direction of linearly polarized light and the reflection characteristics of the sample surface. Two ellipsometric parameters ψ and Δ can be determined in ellipsometry measurement. The ellipsometric parameters ψ and Δ are used to obtain the optical constants of the material and the sample. membrane thickness. Among them, for the ellipsometric parameter ψ, tanψ represents the ratio of the amplitude after reflection of p light and s light, and Δ represents the change in the phase difference between p light and s light.

作为一种可选的实现方式,处理组件14可以根据以下方式计算获得椭偏参数ψ和Δ。As an optional implementation manner, the processing component 14 can calculate and obtain the ellipse parameters ψ and Δ according to the following manner.

S11、调节第二偏振器1311件的方位角至第j个预设角度Wj,每一探测器获得在该方位角下对应的光强值Ij,每一探测器通过检测N个不同方位角下的光强,获得N个光强值。S11. Adjust the azimuth angle of the second polarizer 1311 to the j-th preset angle W j . Each detector obtains the corresponding light intensity value I j at this azimuth angle. Each detector detects N different azimuths. The light intensity under the corner is obtained, and N light intensity values are obtained.

S12、构建光强表示公式,光强表示公式如下:S12. Construct a light intensity expression formula. The light intensity expression formula is as follows:

Ii=a0-i+a2-icos 2A+b2-isin2A+a4-icos4A+b4-isin4AI i =a 0-i +a 2-i cos 2A+b 2-i sin2A+a 4-i cos4A+b 4-i sin4A

式中,Ii为不同探测器获得的光强,a0-i、a2-i、b2-i、a4-i、b4-i为傅里叶系数;In the formula, I i is the light intensity obtained by different detectors, a 0-i , a 2-i , b 2-i , a 4-i , b 4-i are Fourier coefficients;

S13、针对第i个探测器,根据其检测获得的N个不同方位角下对应的光强值,按照离散周期函数傅里叶系数公式计算傅里叶系数,离散周期函数傅里叶系数公式表示如下:S13. For the i-th detector, according to the corresponding light intensity values at N different azimuth angles obtained by its detection, calculate the Fourier coefficient according to the discrete periodic function Fourier coefficient formula, which is expressed by the discrete periodic function Fourier coefficient formula. as follows:

式中,i表示探测器序号,N表示检测的方位角总数,Ij表示探测器i在第j次检测中获得的光强值,Wj表示第二偏振器1311在第j次检测中的方位角。In the formula, i represents the detector serial number, N represents the total number of azimuth angles detected, I j represents the light intensity value obtained by detector i in the j-th detection, and W j represents the intensity value of the second polarizer 1311 in the j-th detection. Azimuth.

S14、根据傅里叶系数计算斯托克斯参量。斯托克斯参量可以通过如下公式计算获得:S14. Calculate Stokes parameters based on Fourier coefficients. Stokes parameters can be calculated by the following formula:

s0-i=4×(a0-i-a4-i)s 0-i =4×(a 0-i -a 4-i )

S15、根据斯托克斯参量,计算获得椭偏参数ψ和Δ。S15. According to the Stokes parameters, calculate the ellipse parameters ψ and Δ.

可以通过如下公式计算椭偏参数ψ和Δ:The ellipsometric parameters ψ and Δ can be calculated by the following formulas:

2ψ=arccos(-s1/s0)2ψ=arccos(-s 1 /s 0 )

Δ=arccos(s2/s0·sin2ψ)Δ=arccos(s 2 /s 0 ·sin2ψ)

当只有单个波长时,是不完全偏振仪,只能获得3个斯托克斯参量,无法判断Δ的正负,同时考虑到测量以及光电探测器的相应误差等,无法解得光学常数。而本申请采用四个激光器组成的四波长的入射光,对于每一波长,均可以求得一组椭偏参数ψ和Δ,因此可以获得四组椭偏参数ψ和Δ。根据每一组椭偏参数ψ和Δ,均可以通过数值反演计算可以求出待测样品的薄膜厚度和光学常数等参数。将根据四组椭偏参数数值反演计算得的薄膜厚度作均值处理,以薄膜厚度的平均值作为样品薄膜厚度的测量结果。类似的,将根据四组椭偏参数数值反演计算得的光学常数作均值处理,以光学常数的平均值作为样品薄膜的光学常数测量结果。When there is only a single wavelength, it is an incomplete polarizer, and only three Stokes parameters can be obtained, and the positive and negative of Δ cannot be judged. At the same time, considering the corresponding errors of measurement and photodetector, the optical constants cannot be solved. This application uses four wavelengths of incident light composed of four lasers. For each wavelength, a set of ellipsometric parameters ψ and Δ can be obtained, so four sets of elliptical parameters ψ and Δ can be obtained. According to each set of ellipsometric parameters ψ and Δ, parameters such as film thickness and optical constants of the sample to be measured can be obtained through numerical inversion calculation. The film thickness calculated based on the numerical inversion of the four sets of ellipsometric parameters is averaged, and the average value of the film thickness is used as the measurement result of the sample film thickness. Similarly, the optical constants calculated based on the numerical inversion of the four sets of ellipsometric parameters were averaged, and the average of the optical constants was used as the optical constant measurement result of the sample film.

根据以上说明可知,本申请实施例提供的薄膜厚度测量装置100可以利用椭偏测量方式获得样品的薄膜厚度和光学常数等参数。According to the above description, it can be seen that the film thickness measurement device 100 provided in the embodiment of the present application can obtain parameters such as film thickness and optical constants of the sample using ellipsometry.

本申请实施例提供的薄膜厚度测量装置100还可以利用光谱测量的方式获得样品的薄膜厚度和光学常数等参数。The film thickness measurement device 100 provided in the embodiment of the present application can also use spectral measurement to obtain parameters such as film thickness and optical constants of the sample.

作为一种可选的实现方式,在光谱测量中,需要先对薄膜基片进行测量定标,定标时偏振器件光轴位于同一平面,分别测量S偏振光和P偏振光的光强,然后放上薄膜样品,获得对应的光强信息,由多光束平板干涉理论可得,P光分量和S光分量的总反射系数为:As an optional implementation method, in spectral measurement, the film substrate needs to be measured and calibrated first. During calibration, the optical axis of the polarizing device is located on the same plane, and the light intensity of S-polarized light and P-polarized light is measured respectively, and then Place the film sample to obtain the corresponding light intensity information. According to the multi-beam plate interference theory, the total reflection coefficient of the P light component and S light component is:

其中,r1p,r1s分别为空气/薄膜界面进行一次反射的P分量的反射系数和S分量的反射系数,r2p,r2s分别为薄膜/基片界面上进行一次反射的P分量的反射系数和S分量的反射系数。2δ是相邻反射光光束之间的相位差,可以通过如下公式表示:Among them, r 1p and r 1s are respectively the reflection coefficient of the P component and the S component that are reflected once at the air/film interface. r 2p and r 2s are the reflection coefficients of the P component that is reflected once at the film/substrate interface. coefficient and the reflection coefficient of the S component. 2δ is the phase difference between adjacent reflected light beams, which can be expressed by the following formula:

式中,而λ为光的波长,n为薄膜的复折射率,为薄膜中的折射角,将测量计算得到的四个波长的反射率带入即可计算得出薄膜的厚度和光学常数。In the formula, λ is the wavelength of light, n is the complex refractive index of the film, is the refraction angle in the film, and the thickness and optical constants of the film can be calculated by bringing in the reflectivity of the four wavelengths calculated by measurement.

根据以上说明可知,本申请实施例提供的薄膜厚度测量装置100可以通过一次测量,同时利用椭偏测量和光谱测量的方式分别计算获得样品的薄膜厚度和光学常数,并根据两者对测量结果进行验证,提高了测量的准确性,同时提高测量的简便性。并且,通过这种方式,本申请实施例提供的薄膜厚度测量装置100可以覆盖完整薄膜测量的厚度范围,可以满足薄膜测量需求。According to the above description, it can be seen that the film thickness measurement device 100 provided by the embodiment of the present application can calculate and obtain the film thickness and optical constants of the sample by using ellipsometry and spectrum measurement in one measurement, and perform the measurement results based on both. Verification improves the accuracy of measurement while improving the simplicity of measurement. Moreover, in this way, the film thickness measurement device 100 provided by the embodiment of the present application can cover the thickness range of the complete film measurement, and can meet the film measurement requirements.

具体的,对于测量几百纳米以上薄膜厚度的情况,可以根据光谱测量的结果作为薄膜的厚度。而对于测量几百纳米以下的薄膜厚度情况,可以将椭偏测量的结果作为样品薄膜的厚度。Specifically, for measuring the thickness of a film above several hundred nanometers, the thickness of the film can be determined based on the results of spectral measurement. For measuring film thickness below a few hundred nanometers, the results of ellipsometry can be used as the thickness of the sample film.

而对于椭偏测量由于薄膜周期性问题会存在多解的情况,本申请将光谱测量与椭偏测量结合,实现自标定。由于厚度的周期数已知,当椭偏测量的测量值(以下简称为椭偏测量值)与光谱测量的测量值(以下简称光谱测量值)均在一个厚度周期范围内时,测量结果输出椭偏测量值,若两者的测量结果之间大于一个厚度周期,则输出光谱测量值作为测量结果。通过这种方式,可以排除膜厚的不确定值,提高膜厚测量精度。As for ellipsometry, there are multiple solutions due to film periodicity issues. This application combines spectral measurement with ellipsometry to achieve self-calibration. Since the period number of thickness is known, when the measured value of ellipsometry (hereinafter referred to as ellipsometric measurement value) and the measured value of spectral measurement (hereinafter referred to as spectral measurement value) are both within a thickness period range, the measurement result output ellipsometry Offset measurement value, if the difference between the two measurement results is greater than one thickness period, the spectrum measurement value will be output as the measurement result. In this way, the uncertain value of film thickness can be eliminated and the accuracy of film thickness measurement can be improved.

作为一种可选的实现方式,本申请实施例提供的薄膜厚度测量装置100中,第二偏振器1311可以采用磁光调制器件。As an optional implementation manner, in the film thickness measurement device 100 provided by the embodiment of the present application, the second polarizer 1311 may use a magneto-optical modulation device.

具体的,磁光调制器件如图3所示。磁光调制器件包括磁光晶体1311a和控制器1311b。Specifically, the magneto-optical modulation device is shown in Figure 3. The magneto-optical modulation device includes a magneto-optical crystal 1311a and a controller 1311b.

磁光调制器件的工作原理为:若一束线偏振光沿磁光晶体轴线方向传播,利用控制器调整缠绕在磁光晶体上的电压,从而在沿着光轴方向产生直流磁场,出射光的偏振面将会旋转一个角度W,这个现象被称为磁光效应,磁光效应满足如下规律:The working principle of the magneto-optical modulation device is: if a beam of linearly polarized light propagates along the axis of the magneto-optical crystal, the controller is used to adjust the voltage wound on the magneto-optical crystal, thereby generating a DC magnetic field along the direction of the optical axis. The polarization plane will rotate by an angle W. This phenomenon is called the magneto-optical effect. The magneto-optical effect satisfies the following rules:

W=VLBW=VLB

其中,W为光波偏振面旋转的角度,V是Verdet(维尔德)常量,L是磁光晶体的长度,B是磁感应强度。通过控制器改变线圈上的电流来改变磁感应的强度B,从而让光波偏振面的旋转角度W。Among them, W is the angle of rotation of the light wave polarization plane, V is the Verdet constant, L is the length of the magneto-optical crystal, and B is the magnetic induction intensity. The controller changes the current on the coil to change the intensity B of the magnetic induction, thereby causing the rotation angle W of the light wave polarization plane.

根据以上说明,本申请采用磁光调制的方式控制第二偏振器1311,减少了运动器件,从而可以增加运行的稳定性,并提高了测量精度。此外,采用磁光调制的方式,对于方位角的调节更为方便迅捷,可以提高测量效率。According to the above description, this application uses magneto-optical modulation to control the second polarizer 1311, which reduces moving components, thereby increasing the stability of operation and improving measurement accuracy. In addition, the use of magneto-optical modulation makes the adjustment of azimuth angle more convenient and faster, which can improve measurement efficiency.

作为一种可选的实现方式,在本申请实施例中,样品台11的设计引入了自动控制的X轴(或Y轴)和旋转结构,在实际测试中,通过控制X轴(或Y轴)位移和载物平面111旋转,将薄膜的每一个点移动至入射面,实现对每一个位置的薄膜厚度测量。As an optional implementation method, in the embodiment of the present application, the design of the sample stage 11 introduces an automatically controlled X-axis (or Y-axis) and rotation structure. In the actual test, by controlling the X-axis (or Y-axis) ) displacement and rotation of the carrier plane 111 move each point of the film to the incident surface to achieve film thickness measurement at each position.

样品台11的结构如图4所示,样品台11包括:载物平面111、五维调节平台112、电动旋转平台113、电动X轴位移平台114。The structure of the sample stage 11 is shown in Figure 4. The sample stage 11 includes: a load plane 111, a five-dimensional adjustment platform 112, an electric rotation platform 113, and an electric X-axis displacement platform 114.

其中,载物平面111用于承载样品。Among them, the loading plane 111 is used to carry the sample.

五维调节平台112用于保障待测样品所在平面与入射平面垂直,并调整让载物平面111中心与入射光轴重合。The five-dimensional adjustment platform 112 is used to ensure that the plane of the sample to be measured is perpendicular to the incident plane, and is adjusted so that the center of the object plane 111 coincides with the incident optical axis.

电动旋转平台113带动载物平面111旋转,从而使待测样品旋转,实现圆周测量。The electric rotating platform 113 drives the load plane 111 to rotate, thereby rotating the sample to be measured and achieving circumferential measurement.

电动X轴位移平台114带动载物平面111前后(或左右)移动,实现距中心不同位置处的测量。The electric X-axis displacement platform 114 drives the load plane 111 to move forward and backward (or left and right) to achieve measurements at different positions from the center.

作为一种可选的实现方式,本申请实施例提供的薄膜厚度测量装置100包括薄膜均匀性测试模式。在薄膜均匀性测试模式下,首先将自动调整零位,设置检测区域后,五维调节平台112、电动旋转平台113、电动X轴位移平台114等装置相互配合,带动样品台11移动,从而薄膜厚度测量装置100可以扫描检测区域内的每一个点,并记录数据,显示膜厚分布并计算均匀性。As an optional implementation, the film thickness measurement device 100 provided by the embodiment of the present application includes a film uniformity test mode. In the film uniformity test mode, the zero position is automatically adjusted first. After setting the detection area, the five-dimensional adjustment platform 112, the electric rotation platform 113, the electric X-axis displacement platform 114 and other devices cooperate with each other to drive the sample stage 11 to move, so that the film The thickness measurement device 100 can scan every point in the detection area, record data, display film thickness distribution and calculate uniformity.

作为一种可选的实现方式,可以将旋转第一、第二、第三偏振器1312的偏光轴均调整到S光平面,由S光分量的总反射系数公式可得,在光学常数(一般同一样品的光学常数默认不变)、波长已知的情况下,总反射率仅和薄膜厚度相关,故可以根据反射率的变化快速得出薄膜的厚度分布。As an optional implementation method, the polarization axes of the rotating first, second, and third polarizers 1312 can all be adjusted to the S light plane. According to the total reflection coefficient formula of the S light component, in the optical constant (generally When the optical constants of the same sample remain unchanged by default) and the wavelength is known, the total reflectance is only related to the thickness of the film, so the thickness distribution of the film can be quickly obtained based on changes in reflectivity.

为了进一步说明本申请实施例提供的薄膜厚度测量装置100,如图5所示,本申请还提供一种薄膜厚度测量方法,该方法基于如上所述的薄膜厚度测量装置100进行。In order to further illustrate the film thickness measurement device 100 provided by the embodiment of the present application, as shown in FIG. 5 , the present application also provides a film thickness measurement method, which is based on the film thickness measurement device 100 as described above.

首先,定义入射光与接触面法线构成的平面为入射面,反射光与接触面法向量构成的平面为反射面。在偏极光的讨论中,电场的垂直分量S与水平分量P均是针对这两个平面。First, define the plane formed by the incident light and the normal vector of the contact surface as the incident surface, and the plane formed by the reflected light and the normal vector of the contact surface as the reflective surface. In the discussion of polarized light, the vertical component S and the horizontal component P of the electric field are both directed to these two planes.

薄膜厚度测量方法包括以下步骤:The film thickness measurement method includes the following steps:

S1、根据样品上薄膜的折射率范围,设置入射光的入射角度。S1. Set the incident angle of the incident light according to the refractive index range of the film on the sample.

S2、样品台11上放置样品基片,并将第一至第三偏振器1312的偏光轴先后调节至P分量和S分量,调整样品台11和接收端13,获得合适信号,并记录作为基线。S2. Place the sample substrate on the sample stage 11, adjust the polarization axes of the first to third polarizers 1312 to the P component and S component successively, adjust the sample stage 11 and the receiving end 13, obtain a suitable signal, and record it as the baseline .

S3、将样品放置在样品台11上,样品中心与样品台11中心对准。S3. Place the sample on the sample stage 11, and align the center of the sample with the center of the sample stage 11.

S4、调节第一至第三偏振器1312,采集光强数据,根据椭偏测量原理对光强数据进行处理,获得椭偏参数,并根据椭偏参数获得椭偏测量结果,椭偏测量结果包括样品的薄膜厚度的椭偏测量值和对应的光学常数。S4. Adjust the first to third polarizers 1312, collect light intensity data, process the light intensity data according to the ellipsometry principle, obtain ellipsometry parameters, and obtain ellipsometry measurement results based on the ellipsometry parameters. The ellipsometry measurement results include Ellipsometric measurements of the film thickness of the sample and the corresponding optical constants.

步骤S4中包括以下步骤:Step S4 includes the following steps:

S41、控制第一偏振器1231的偏光轴与入射光的入射面成45°角,第三偏振器1312的偏光轴与入射面成0°角。S41. Control the polarization axis of the first polarizer 1231 to form an angle of 45° with the incident surface of the incident light, and control the polarization axis of the third polarizer 1312 to form an angle of 0° with the incident surface.

S42、调节第二偏振器1311,使得第二偏振器1311的初始偏光轴位置与入射面成0°角。S42. Adjust the second polarizer 1311 so that the initial polarization axis position of the second polarizer 1311 forms an angle of 0° with the incident surface.

S43、采用磁光调制改变第二偏振器1311的方位角,方位角每改变θ,记录一次光强数据。S43. Use magneto-optical modulation to change the azimuth angle of the second polarizer 1311. Each time the azimuth angle changes θ, light intensity data is recorded.

S44、根据椭偏测量原理对光强数据进行处理,获得椭偏参数,并根据椭偏参数获得样品的薄膜厚度的椭偏测量值和对应的光学常数。S44. Process the light intensity data according to the ellipsometry principle to obtain the ellipsometry parameters, and obtain the ellipsometry measurement value of the film thickness of the sample and the corresponding optical constants based on the ellipsometry parameters.

S5、调节第一至第三偏振器1312,采集光强数据,根据光谱测量原理对光强数据进行处理,计算样品薄膜对不同波长光束的反射率,并根据反射率获得光谱测量结果,光谱测量结果包括样品的薄膜厚度的光谱测量值和对应的光学常数。S5. Adjust the first to third polarizers 1312, collect light intensity data, process the light intensity data according to the principle of spectral measurement, calculate the reflectivity of the sample film to light beams of different wavelengths, and obtain spectral measurement results based on the reflectance. Spectral measurement Results include spectral measurements of the sample's film thickness and corresponding optical constants.

步骤S5中包括以下步骤:Step S5 includes the following steps:

S51、将第一至第三偏振器1312的偏光轴先后调整到p分量和s分量。S51. Adjust the polarization axes of the first to third polarizers 1312 to the p component and the s component successively.

S52、记录并处理四个波长对应的光强,根据光强,由多光束平板干涉理论计算得薄膜对四个波长光束的反射率。S52. Record and process the light intensities corresponding to the four wavelengths. Based on the light intensity, the reflectivity of the film to the four wavelength beams is calculated based on the multi-beam plate interference theory.

S53根据四个波长光束的反射率计算得薄膜厚度的光谱测量值和对应的光学常数。S53 calculates the spectral measurement value of the film thickness and the corresponding optical constants based on the reflectivity of the four wavelength beams.

S6、将椭偏测量结果与光谱测量结果对比,当椭偏测量值与光谱测量值均在一个厚度周期范围内时,测量结果输出椭偏测量值,若两者的测量结果之间大于一个厚度周期,则输出光谱测量值作为测量结果。S6. Compare the ellipsometry measurement results with the spectrum measurement results. When the ellipsometry measurement value and the spectrum measurement value are both within a thickness period, the measurement results output the ellipsometry measurement value. If the difference between the two measurement results is greater than one thickness. period, the spectrum measurement value is output as the measurement result.

以上所揭露的仅为本申请的较佳实施例而已,然其并非用以限定本申请之权利范围,本领域普通技术人员可以理解:在不脱离本申请及所附的权利要求的精神和范围内,改变、修饰、替代、组合、简化,均应为等效的置换方式,仍属于发明所涵盖的范围。What is disclosed above is only the preferred embodiment of the present application, but it is not used to limit the scope of rights of the present application. Those of ordinary skill in the art can understand that: without departing from the spirit and scope of the present application and the appended claims, Within the scope of the invention, changes, modifications, substitutions, combinations, and simplifications should all be equivalent substitutions and still fall within the scope of the invention.

Claims (10)

1.一种薄膜厚度测量装置,包括样品台,所述样品台用于承载样品,所述薄膜厚度测量装置用于检测所述样品的薄膜厚度和光学常数,其特征在于,所述薄膜厚度测量装置包括:1. A film thickness measurement device, comprising a sample stage, the sample stage is used to carry a sample, and the film thickness measurement device is used to detect the film thickness and optical constants of the sample, characterized in that the film thickness measurement Devices include: 发射端,所述发射端用于向所述样品台上的样品发射入射光,所述入射光由四个波长不同的激光汇合形成,并且,所述发射端可以将所述入射光调节为线偏振光;The emission end is used to emit incident light to the sample on the sample stage. The incident light is formed by the convergence of four lasers with different wavelengths, and the emission end can adjust the incident light into a line. polarized light; 接收端,所述接收端用于接收所述样品反射形成的出射光,所述接收端包括检偏组件和探测组件,通过调节所述检偏组件,实现对不同方位角下出射光强的探测,在每一方位角下,获得一组四个所述激光的波长对应的光强值;The receiving end is used to receive the outgoing light formed by the reflection of the sample. The receiving end includes an analyzer component and a detection component. By adjusting the analyzer component, the detection of the outgoing light intensity at different azimuth angles is achieved. , at each azimuth angle, obtain a set of four light intensity values corresponding to the wavelengths of the laser; 处理组件,根据所述方位角和所述光强值,分别采用椭偏测量和光谱测量的计算方法,获得所述样品的薄膜厚度和光学参数,并将两者方法计算得的薄膜厚度进行对比,以确定样品的薄膜厚度取值。The processing component, according to the azimuth angle and the light intensity value, uses the calculation methods of ellipsometry and spectral measurement respectively to obtain the film thickness and optical parameters of the sample, and compares the film thickness calculated by the two methods. , to determine the film thickness value of the sample. 2.根据权利要求1所述的薄膜厚度测量装置,其特征在于,2. The film thickness measuring device according to claim 1, characterized in that, 所述发射端包括:The transmitter includes: 光源组件,包括四个激光发射器,各个所述激光发射器所发射的激光波长各不相同;The light source component includes four laser emitters, and the laser wavelengths emitted by each of the laser emitters are different; 分束器组,包括级联的分束器,将各个所述激光发射器所发射的激光组合成公共光束;A beam splitter group, including a cascade of beam splitters, combines the lasers emitted by each of the laser transmitters into a common beam; 起偏组件,包括第一偏振器,所述第一偏振器可旋转方位角,用于将所述公共光束转换为线偏振光,并将转换为所述线偏振光的所述公共光束作为入射光。A polarizing component, including a first polarizer, the first polarizer can rotate the azimuth angle, and is used to convert the common light beam into linearly polarized light, and use the common light beam converted into the linearly polarized light as the incident light. Light. 3.根据权利要求1所述的薄膜厚度测量装置,其特征在于,3. The film thickness measuring device according to claim 1, characterized in that, 所述接收端包括:The receiving end includes: 检偏组件,包括第二偏振器和第三偏振器,所述入射光经过所述样品表面反射后形成出射光,所述出射光依次经过所述第二偏振器和所述第三偏振器,所述第二偏振器和所述第三偏振器的方位角可调;An analyzer component, including a second polarizer and a third polarizer, the incident light is reflected by the sample surface to form outgoing light, and the outgoing light passes through the second polarizer and the third polarizer in sequence, The azimuth angles of the second polarizer and the third polarizer are adjustable; 二向色镜组,所述二向色镜组包括三个二向色镜,各个所述二向色镜同光轴排列,所述出射光经过所述二向色镜时部分反射、部分透射,以将不同波长的光分离;Dichroic mirror group, the dichroic mirror group includes three dichroic mirrors, each of the dichroic mirrors is arranged on the same optical axis, and the outgoing light is partially reflected and partially transmitted when passing through the dichroic mirror. , to separate light of different wavelengths; 探测组件,包括四个探测器,其中三个所述探测器分别接收各个所述二向色镜反射的光束,剩余一个所述探测器接收从最后一个所述二向色镜透射的光束,所述探测器用于探测所接收光束的光强。The detection component includes four detectors, three of which respectively receive the light beams reflected by each of the dichroic mirrors, and the remaining one of the detectors receives the light beams transmitted from the last dichroic mirror, so The detector is used to detect the light intensity of the received light beam. 4.根据权利要求3所述的薄膜厚度测量装置,其特征在于,4. The film thickness measuring device according to claim 3, characterized in that, 所述第二偏振器采用磁光调制器件。The second polarizer uses a magneto-optical modulation device. 5.根据权利要求1所述的薄膜厚度测量装置,其特征在于,5. The film thickness measuring device according to claim 1, characterized in that, 所述处理组件通过如下公式计算椭偏参数ψ和Δ:The processing component calculates the ellipsometric parameters ψ and Δ through the following formulas: 2ψ=arccos(-s1/s0)2ψ=arccos(-s 1 /s 0 ) Δ=arccos(s2/s0·sin 2ψ)Δ=arccos(s 2 /s 0 ·sin 2ψ) 式中,s0、s1、s2表示斯托克斯参量,通过如下公式计算:In the formula, s 0 , s 1 , and s 2 represent Stokes parameters, which are calculated by the following formula: s0-i=4×(a0-i-a4-i)s 0-i =4×(a 0-i -a 4-i ) 式中,a0-i、a2-i、b2-i、a4-i、b4-i为傅里叶系数,通过如下公式计算获得:In the formula, a 0-i , a 2-i , b 2-i , a 4-i , and b 4-i are Fourier coefficients, which are calculated by the following formula: 式中,i表示探测器序号,N表示检测的方位角总数,Ij表示探测器i在第j次检测中获得的光强值,Wj表示第二偏振器在第j次检测中的方位角;In the formula, i represents the detector serial number, N represents the total number of azimuth angles detected, I j represents the light intensity value obtained by detector i in the j-th detection, and W j represents the orientation of the second polarizer in the j-th detection. horn; 所述处理组件根据所述椭偏参数ψ和Δ,通过数值反演计算获得样品薄膜厚度的椭偏测量值和对应的光学常数。The processing component obtains the ellipsometry measurement value of the sample film thickness and the corresponding optical constants through numerical inversion calculation based on the ellipsometric parameters ψ and Δ. 6.根据权利要求1所述的薄膜厚度测量装置,其特征在于,6. The film thickness measuring device according to claim 1, characterized in that, 所述处理组件还根据S偏振光和P偏振光的光强,计算P光分量和S光分量的总反射系数,所述P光分量和所述S光分量的总反射系数通过如下公式表示:The processing component also calculates the total reflection coefficient of the P light component and the S light component based on the light intensity of the S polarized light and the P polarized light. The total reflection coefficient of the P light component and the S light component is expressed by the following formula: 其中,r1p,r1s分别为空气/薄膜界面进行一次反射的P分量的反射系数和S分量的反射系数,r2p,r2s分别为薄膜/基片界面上进行一次反射的P分量的反射系数和S分量的反射系数,2δ是相邻反射光光束之间的相位差,通过如下公式表示:Among them, r 1p and r 1s are respectively the reflection coefficient of the P component and the S component that are reflected once at the air/film interface. r 2p and r 2s are the reflection coefficients of the P component that is reflected once at the film/substrate interface. coefficient and the reflection coefficient of the S component, 2δ is the phase difference between adjacent reflected light beams, expressed by the following formula: 式中,而λ为光的波长,n为薄膜的复折射率,为薄膜中的折射角;In the formula, λ is the wavelength of light, n is the complex refractive index of the film, is the refraction angle in the film; 所述处理组件还根据计算得到的所述薄膜对四个波长的反射率,计算得出薄膜厚度的光谱测量值和对应的光学常数。The processing component also calculates the spectral measurement value of the film thickness and the corresponding optical constant based on the calculated reflectivity of the film at four wavelengths. 7.根据权利要求1所述的薄膜厚度测量装置,其特征在于,7. The film thickness measuring device according to claim 1, characterized in that, 所述处理组件根据椭偏测量原理对光强数据进行处理,获得椭偏参数,并根据椭偏参数获得椭偏测量结果,所述椭偏测量结果包括样品的薄膜厚度的椭偏测量值和对应的光学常数;The processing component processes the light intensity data according to the ellipsometry principle to obtain ellipsometry parameters, and obtains ellipsometry measurement results based on the ellipsometry parameters. The ellipsometry measurement results include the ellipsometry measurement value of the film thickness of the sample and the corresponding optical constants; 所述处理组件还根据光谱测量原理对光强数据进行处理,计算样品薄膜对不同波长光束的反射率,并根据反射率获得光谱测量结果,所述光谱测量结果包括样品的薄膜厚度的光谱测量值和对应的光学常数;The processing component also processes the light intensity data according to the principle of spectral measurement, calculates the reflectivity of the sample film to light beams of different wavelengths, and obtains spectral measurement results based on the reflectance. The spectral measurement results include spectral measurement values of the film thickness of the sample. and corresponding optical constants; 所述处理组件还将所述椭偏测量结果与所述光谱测量结果对比,当椭偏测量值与光谱测量值均在一个厚度周期范围内时,测量结果输出椭偏测量值,若两者的测量结果之间大于一个厚度周期,则输出光谱测量值作为测量结果。The processing component also compares the ellipsometry measurement result with the spectrum measurement result. When the ellipsometry measurement value and the spectrum measurement value are both within a thickness period range, the measurement result outputs the ellipsometry measurement value. If the two If the interval between measurement results is greater than one thickness period, the spectrum measurement value will be output as the measurement result. 8.根据权利要求1所述的薄膜厚度测量装置,其特征在于,所述样品台包括:8. The film thickness measuring device according to claim 1, wherein the sample stage includes: 载物平面用于承载样品;The loading plane is used to carry the sample; 五维调节平台用于保障待测样品所在平面与入射平面垂直,并调整让载物平面中心与入射光轴重合;The five-dimensional adjustment platform is used to ensure that the plane of the sample to be measured is perpendicular to the incident plane, and is adjusted so that the center of the carrier plane coincides with the incident optical axis; 电动旋转平台带动载物平面旋转,从而使待测样品旋转,实现圆周测量。The electric rotating platform drives the load plane to rotate, thereby rotating the sample to be measured and achieving circumferential measurement. 9.一种薄膜厚度测量方法,其特征在于,所述方法基于如权利要求1~8任一项所述的薄膜厚度测量装置进行,所述方法包括一下步骤:9. A method for measuring film thickness, characterized in that the method is based on the film thickness measuring device according to any one of claims 1 to 8, and the method includes the following steps: S1、根据样品上薄膜的折射率范围,设置入射光的入射角度;S1. Set the incident angle of the incident light according to the refractive index range of the film on the sample; S2、样品台上放置样品基片,并将第一至第三偏振器的偏光轴先后调节至P分量和S分量,调整样品台和接收端,获得合适信号,并记录作为基线;S2. Place the sample substrate on the sample stage, adjust the polarization axes of the first to third polarizers to the P component and S component successively, adjust the sample stage and the receiving end, obtain a suitable signal, and record it as the baseline; S3、将样品放置在样品台上,样品中心与样品台中心对准;S3. Place the sample on the sample stage and align the center of the sample with the center of the sample stage; S4、调节第一至第三偏振器,采集光强数据,根据椭偏测量原理对所述光强数据进行处理,获得椭偏参数,并根据所述椭偏参数获得椭偏测量结果,所述椭偏测量结果包括样品的薄膜厚度的椭偏测量值和对应的光学常数;S4. Adjust the first to third polarizers, collect light intensity data, process the light intensity data according to the ellipsometry measurement principle, obtain ellipsometry parameters, and obtain ellipsometry measurement results according to the ellipsometry parameters. The ellipsometry measurement results include the ellipsometry measurement value of the film thickness of the sample and the corresponding optical constants; S5、调节第一至第三偏振器,采集光强数据,根据光谱测量原理对所述光强数据进行处理,计算样品薄膜对不同波长光束的反射率,并根据所述反射率获得光谱测量结果,所述光谱测量结果包括样品的薄膜厚度的光谱测量值和对应的光学常数;S5. Adjust the first to third polarizers, collect light intensity data, process the light intensity data according to the principle of spectral measurement, calculate the reflectivity of the sample film to light beams of different wavelengths, and obtain spectral measurement results based on the reflectance. , the spectral measurement results include the spectral measurement value of the film thickness of the sample and the corresponding optical constant; S6、将所述椭偏测量结果与所述光谱测量结果对比,当所述椭偏测量值与所述光谱测量值均在一个厚度周期范围内时,输出所述椭偏测量值作为测量结果,若两者的测量结果之间大于一个厚度周期,则输出所述光谱测量值作为测量结果。S6. Compare the ellipsometry measurement result with the spectrum measurement result. When the ellipsometry measurement value and the spectrum measurement value are both within a thickness period range, output the ellipsometry measurement value as the measurement result, If the difference between the two measurement results is greater than one thickness period, the spectrum measurement value is output as the measurement result. 10.根据权利要求9所述的薄膜厚度测量方法,其特征在于,10. The film thickness measurement method according to claim 9, characterized in that, 所述步骤S4中包括以下步骤:The step S4 includes the following steps: S41、控制第一偏振器的偏光轴与入射光的入射面成45°角,第三偏振器的偏光轴与入射面成0°角;S41. Control the polarization axis of the first polarizer to form an angle of 45° with the incident surface of the incident light, and the polarization axis of the third polarizer to form an angle of 0° with the incident surface; S42、调节第二偏振器,使得第二偏振器的初始偏光轴位置与入射面成0°角;S42. Adjust the second polarizer so that the initial polarization axis position of the second polarizer forms an angle of 0° with the incident surface; S43、采用磁光调制改变第二偏振器的方位角,方位角每改变θ,记录一次光强数据;S43. Use magneto-optical modulation to change the azimuth angle of the second polarizer. Every time the azimuth angle changes θ, record the light intensity data; S44、根据椭偏测量原理对光强数据进行处理,获得椭偏参数,并根据椭偏参数获得样品的薄膜厚度的椭偏测量值和对应的光学常数。S44. Process the light intensity data according to the ellipsometry principle to obtain the ellipsometry parameters, and obtain the ellipsometry measurement value of the film thickness of the sample and the corresponding optical constants based on the ellipsometry parameters.
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