Sample analysis method and sample analysis device

Abstract

To improve analytical efficiency when analyzing multiple sites on a sample using an ellipsometer.SOLUTION: A sample analysis method for analyzing a sample W is provided, the method involving the use of a sputtering device 2 for sputtering multiple sites on the sample W, and an ellipsometer 3 for analyzing the multiple sputtered sites.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sample analysis method and a sample analysis device. [Background technology]

[0002] Conventionally, a spectroscopic ellipsometer has been used to analyze the properties of a substrate or a thin film on a substrate, as shown in Patent Document 1. This spectroscopic ellipsometer measures the amount of change in polarization between incident light and reflected light for each wavelength, creates an optical model based on the obtained measurement data, and performs fitting calculations to determine the film thickness (d) and optical constants (refractive index n, extinction coefficient k) of the thin film in a non-destructive and non-contact manner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-236900 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to analyze the film thickness (d) and optical constants (refractive index n, extinction coefficient k) of each layer in the multilayer substrate, an analysis sample consisting of only the substrate and a number of analysis samples each consisting of a top layer of the multilayer substrate are prepared. Each analysis sample is then analyzed using a spectroscopic ellipsometer.

[0005] However, it is necessary to analyze each of the multiple analytical samples using the spectroscopic ellipsometer, and the time and effort required to replace the analytical samples reduces the efficiency of sample analysis.

[0006] Therefore, the present invention has been made in consideration of the above-mentioned problems, and has as its main object to improve the analysis efficiency when multiple locations on a sample are analyzed by an ellipsometer. [Means for solving the problem]

[0007] In other words, the sample analysis method of the present invention is a sample analysis method for analyzing a sample, characterized in that multiple locations on the sample are sputtered using a sputtering device, and the multiple sputtered locations are analyzed using an ellipsometer.

[0008] In this sample analysis method, multiple locations on the sample are sputtered and the sputtered locations are analyzed by an ellipsometer, so there is no need to prepare multiple dedicated analytical samples corresponding to the multiple locations on the sample. As a result, when multiple locations on a sample are analyzed by an ellipsometer, the analysis efficiency can be improved.

[0009] The sputtering device is preferably a glow discharge optical emission spectrometer. With this configuration, the composition (element information) of the sputtered portion can be analyzed by the glow discharge optical emission analyzer, and the analysis results can be used for analysis by the ellipsometer.

[0010] It is desirable that the sputtering apparatus be used to cause the sample to have different sputter depths at a plurality of locations. With this configuration, it is possible to analyze a plurality of locations within the sample that are at different depth positions from the surface.

[0011] In the sample analysis method according to the present invention, it is preferable that the sample to be analyzed is a multilayer substrate. With this configuration, each layer of the multilayer substrate can be analyzed by the ellipsometer without the need to prepare a dedicated analysis sample with each layer of the multilayer substrate as the uppermost layer.

[0012] Specifically, it is desirable to perform sputtering using the sputtering device so that the sputtering reaches different layers at multiple locations on the multi-layer substrate. With this configuration, each layer of the multilayer substrate can be analyzed by the ellipsometer without the need to prepare a dedicated analysis sample with each layer of the multilayer substrate as the top layer. In this configuration, it is particularly preferable to use the glow discharge optical emission analyzer as the sputtering device. When a glow discharge optical emission analyzer is used, the analysis results indicate which layer has been sputtered and that the sputtering depth has reached the desired layer.

[0013] In the sample analysis method according to the present invention, it is desirable to adjust sputtering conditions such as the sputtering rate of the sputtering device using the analysis results obtained by the ellipsometer. With this configuration, the sputtering depth can be determined with high accuracy by adjusting the sputtering conditions of the sputtering device.

[0014] In addition, when the sputtering device is a glow discharge optical emission analyzer, the analysis results obtained by the glow discharge optical emission analyzer can be used for the analysis by the ellipsometer. Also, the analysis results obtained by the ellipsometer can be used for the analysis by the glow discharge optical emission analyzer.

[0015] In addition, the sample analysis apparatus according to the present invention is a sample analysis apparatus that analyzes a sample, and is characterized by comprising a sputtering device that sputters multiple locations on the sample, and an ellipsometer that analyzes the multiple sputtered locations. Effect of the Invention

[0016] According to the present invention as described above, when the inside of a sample is analyzed at a plurality of locations, the efficiency of the analysis can be improved. [Brief description of the drawings]

[0017] [Figure 1] 1 is an overall schematic diagram of a sample analyzer according to an embodiment of the present invention; [Diagram 2] 4 is a flowchart of a sample analysis method according to the embodiment. [Diagram 3] FIG. 13 is a cross-sectional view showing an etched sample of an alternative embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] <One embodiment of the present invention> DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sample analyzing apparatus and a sample analyzing method according to the present invention will be described below with reference to the drawings. In addition, in any of the drawings shown below, for the purpose of easy understanding, some parts are omitted or exaggerated in schematic form as appropriate. The same components are denoted by the same reference numerals and the description thereof is omitted as appropriate.

[0019] <Configuration of sample analyzer 100> As shown in FIG. 1, the sample analyzer 100 of this embodiment includes a sputtering device 2 that sputters a plurality of locations on a sample W, and an ellipsometer 3 that analyzes each of the plurality of locations sputtered by the sputtering device 2.

[0020] Here, the sample W of this embodiment is a multilayer substrate, and for example, four multilayer films W1 to W4 are formed on a base material W0 as shown in Fig. 2. Here, a gallium nitride (GaN) layer as a first layer W1, an aluminum gallium nitride (AlGaN) layer as a second layer W2, a gallium nitride (GaN) layer as a third layer W3, and an aluminum gallium nitride (AlGaN) layer as a fourth layer W4 are formed on a sapphire base material W0.

[0021] The sputtering apparatus 2 sputters a plurality of locations of the sample W to expose the inside of the sample W to the outside. The sputtering apparatus 2 of this embodiment is a glow discharge optical emission spectrometry apparatus.

[0022] This glow discharge optical emission spectrometer 2 analyzes a sample by measuring the spectrum of light emitted by sputtering accompanying a glow discharge.

[0023] Specifically, the glow discharge optical emission analyzer 2 comprises a glow discharge tube 21 that generates a glow discharge in the sample W, a power supply unit 22 that applies a high-frequency voltage to the glow discharge tube 21, a gas supply unit 23 that supplies an inert gas (e.g., argon gas) required for the measurement to the glow discharge tube 21, a spectrometer 24 that separates the light generated from the glow discharge tube 21 and measures the intensity of each spectral component, and an analysis control unit 25 that acquires the measurement signal from the spectrometer 24 and performs analysis of the sample components, etc.

[0024] The sputtering device 2 makes the sputtering depths of the multiple locations of the sample W different from one another. Specifically, each location of the sample W is sputtered in sequence to make the sputtering depths of the locations different from one another. The size of the opening for sputtering is equal to or larger than the irradiation diameter of the incident light of the ellipsometer 3.

[0025] More specifically, the sputtering device 2 sputters the sample W so that the sputtering reaches different layers at multiple locations. That is, in the case of a multilayer substrate in which four multilayer films W1 to W4 are formed on a base material W0, at least four locations are sputtered. The four sputtering locations SP1 to SP4 reach different layers or base materials. The first sputtering location SP1 reaches the base material W0, the second sputtering location SP2 reaches the first layer W1, the third sputtering location SP3 reaches the second layer W2, and the fourth sputtering location SP4 reaches the third layer W3. Here, the sputtering locations SP1 to SP4 reaching the base material W0 or each layer W1 to W3 means that the bottom surface of the sputtering locations SP1 to SP4 is formed of the base material W0 or each layer W1 to W3.

[0026] Here, the sputtering depth at each of the sputtering points SP1 to SP4 is controlled based on the analysis results of the sample components obtained by the analysis control unit 25. (a) At the first sputtering point SP1, it is determined whether or not a component (sapphire) of the base material W0 is detected. (b) At the second sputtering location SP2, it is determined whether or not the component of the first layer W1 (GaN) is detected after the component of the fourth layer W4 (AlGaN), the component of the third layer W3 (GaN), and the component of the second layer W2 (AlGaN). (c) At the third sputtering point SP3, it is determined whether or not the component of the second layer W2 (AlGaN) is detected after the component of the fourth layer W4 (AlGaN) and the component of the third layer W3 (GaN). (d) At the fourth sputtering point SP4, it is determined whether or not the component of the third layer W3 (GaN) is detected after the component of the fourth layer W4 (AlGaN).

[0027] The ellipsometer 3 analyzes the multiple sputtering locations SP1 to SP4 that are sputtered by the sputtering device 2. The ellipsometer 3 analyzes the bottom surface of each of the sputtering locations SP1 to SP4.

[0028] The ellipsometer 3 is a spectroscopic ellipsometer that measures the characteristics of the sample W, such as its film thickness and optical constants (refractive index, extinction coefficient), by observing the change in the polarization state of the reflected light relative to the incident light when light is incident on the sample W and reflected.

[0029] Specifically, the spectroscopic ellipsometer 3 can detect Ψ and Δ at high speed, for example, by the action of a rotating compensator. In FIG. 1, reference numeral 31 denotes a light source, and in this example, a xenon lamp is used. Reference numeral 32 denotes a polarizer, reference numeral 33 denotes a rotating compensator, reference numeral W denotes a sample to be analyzed, reference numeral 34 denotes a rotating analyzer, reference numeral 35 denotes a spectrometer, and reference numeral 36 denotes an information processing device that takes in and processes data output from the spectrometer 35. Reference numeral 37 denotes an optical fiber for guiding light from the light source 31 to the polarizer 32, and reference numeral 38 denotes an optical fiber for introducing light that has passed through the rotating analyzer 34 and guiding it to the spectrometer 35. The information processing device 36 approximates fitting data determined by a plurality of parameters to actual measurement data consisting of Δ values ​​and Ψ values ​​for each wavelength, or values ​​directly calculated from these Δ values ​​and Ψ values, and calculates the characteristics of the sample W from the values ​​of the parameters that determine the approximate fitting data.

[0030] <Sample analysis method> Next, a sample analysis method using the above-described sample analyzer 100 will be described with reference to FIG.

[0031] First, a single sample W, which is a multilayer substrate, is prepared (step S1). The sample W to be prepared may be a finished product or a semi-finished product.

[0032] Then, the sample W is set in the glow discharge optical emission analyzer 2, and sputtering is performed at multiple locations on one sample W (step S2). Then, using the glow discharge optical emission analyzer 2, sputtering is performed so that the multiple locations on the sample W reach different layers, as described above (see FIG. 1). Here, the sputtering depth of each of the sputtering locations SP1-SP4 is controlled based on the analysis results (composition) of the glow discharge optical emission analyzer 2. The sputtering depth of each of the sputtering locations SP1-SP4 may be controlled by the user by checking the analysis results, or may be controlled automatically by the analysis control unit 25.

[0033] Next, the sample W, which has been sputtered at multiple locations, is analyzed by the spectroscopic ellipsometer 3 (step S3). Here, the multiple sputtered locations SP1 to SP4 and the non-sputtered surface are each analyzed by the spectroscopic ellipsometer 3. This makes it possible to analyze the film thickness or optical constants (refractive index, extinction coefficient) of the base material W0 and each of the layers W1 to W4 constituting the multilayer substrate.

[0034] <Effects of this embodiment> According to the sample analyzer 100 of the present embodiment configured as described above, multiple locations on the sample W are sputtered and the sputtered locations are analyzed by the ellipsometer 3, so there is no need to prepare multiple dedicated analysis samples corresponding to the multiple locations on the sample W. As a result, when the inside of the sample W at multiple locations is analyzed by the ellipsometer 3, the analysis efficiency can be improved.

[0035] Furthermore, according to this embodiment, a glow discharge optical emission analyzer is used as the sputtering device 2, so that the composition (elemental information) of the sputtered portion can be analyzed by the glow discharge optical emission analyzer, and the analysis results can be used for analysis by the ellipsometer 3.

[0036] Furthermore, according to this embodiment, since the sputtering apparatus 2 sputters at multiple locations on the multilayer substrate so as to reach different layers, each layer of the multilayer substrate can be analyzed by an ellipsometer without the need to prepare a dedicated analysis sample with each layer of the multilayer substrate as the top layer. Here, since a glow discharge optical emission analyzer is used as the sputtering apparatus 2, the analysis results indicate which layer has been sputtered and that the sputtering depth has reached the desired layer.

[0037] <Other embodiments> For example, in the above embodiment, a plurality of locations on the sample are sputtered, but a single location on the sample may be sputtered. In this case, the ellipsometer may analyze the single sputtered location, or may analyze the single sputtered location and the non-sputtered sample surface.

[0038] Alternatively, sputtering may be performed so as to reach only an unknown layer in a multilayer substrate, and the sputtering location may be analyzed by the ellipsometer 3. In this case, the layer below the unknown layer is a known layer or a known substrate, and the information on the known layer or known substrate may be, for example, information stored in a database or memory.

[0039] In the above embodiment, the sputtering depths are different from one another at the multiple sputtering locations, but the sputtering depths may be the same at multiple sputtering locations. In a multi-layer substrate, the sputtering depths may be set to a depth that reaches the same layer at multiple sputtering locations. With this configuration, the film thickness or optical constants (refractive index, extinction coefficient) of the sample W in its plane can be analyzed.

[0040] In the above embodiment, the sputtering points are separated from one another, but as shown in Fig. 3, the sputtering points SP1 to SP4 may be continuous with one another. Fig. 3(a) shows an embodiment in which the adjacent sputtering points SP1 to SP4 are continuous with one another. Fig. 3(b) shows an embodiment in which the sputtering points SP1 to SP4 with a deeper sputtering depth are formed inside the sputtering points SP1 to SP4 with a shallower sputtering depth.

[0041] Furthermore, the sample analyzer 100 can also adjust sputtering conditions such as the sputtering rate of the sputtering apparatus 2 using the analysis results (e.g., film thickness) obtained by the ellipsometer 3. In this case, it is conceivable that the analysis results of the ellipsometer 3 are transmitted or input to the analysis control unit 25 of the sputtering apparatus 2, and the analysis control unit 25 that receives the analysis results adjusts the sputtering conditions such as the sputtering rate. With this configuration, the sputtering depth can be accurately determined by the sputtering apparatus 2 by adjusting the sputtering conditions such as the sputtering rate of the sputtering apparatus 2.

[0042] Furthermore, the sample analyzer 100 can also use the analysis results obtained by the glow discharge optical emission analyzer 2 for analysis by the ellipsometer 3. In this case, it is considered that the analysis results of the glow discharge optical emission analyzer 2 are transmitted or input to the information processing device 36 of the ellipsometer 3, and the information processing device 36 receiving the analysis results calculates the characteristics of the sample W using the analysis results of the glow discharge optical emission analyzer 2.

[0043] Furthermore, the sample analyzer 100 can use the analysis results obtained by the ellipsometer 3 in the analysis by the glow discharge optical emission analyzer 2 .

[0044] The sputtering apparatus in the above embodiment is a glow discharge optical emission spectrometer, but may be other types of sputtering apparatus.

[0045] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention. [Explanation of symbols]

[0046] 100... Sample analysis device W ··· Sample (multilayer board) 2. Sputtering equipment (glow discharge optical emission analyzer) 25 Analysis control section 3. Ellipsometer 36 Information processing device

Claims

1. A sample analysis method for analyzing a sample, comprising the steps of: sputtering a plurality of locations of the sample using a sputtering device; A sample analysis method comprising: analyzing the sputtered portions by an ellipsometer.

2. 2. The sample analysis method according to claim 1, wherein the sputtering device is a glow discharge optical emission spectrometer.

3. 3. The method of claim 1, wherein the sputtering device causes a plurality of locations on the sample to have different sputter depths.

4. 4. The method for analyzing a sample according to claim 1, wherein the sample is a multilayer substrate.

5. 5. The method of claim 4, wherein said sputtering device sputters said multilayer substrate at a plurality of locations so as to reach different layers from one another.

6. 6. The method of claim 1, further comprising adjusting sputtering conditions of the sputtering apparatus using the analysis results obtained by the ellipsometer.

7. 3. The sample analysis method according to claim 2, further comprising the step of calculating characteristics of the sample measured by the ellipsometer using analysis results obtained by the glow discharge optical emission analyzer.

8. A sample analysis device for analyzing a sample, comprising: A sputtering device for sputtering a plurality of locations on the sample; and an ellipsometer for analyzing the plurality of sputtered locations.

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