KR100927979B1 - Composition and structure analysis method of nano thin film using angular decomposition photoelectron spectrometer - Google Patents

Abstract

A composition and structure analysis method of a nano thin film according to the present invention includes: inputting at least one of an arbitrary composition ratio of a nano thin film and a thickness of a thin film layer; Obtaining a theoretical photoelectron intensity value according to the input arbitrary composition ratio and thickness of the thin film layer; Obtaining an optoelectronic intensity ratio according to the theoretical optoelectronic intensity value; Measuring the photoelectron intensity value of the particular nano thin film; Obtaining an actual photoelectron intensity ratio according to the measured photoelectron intensity value; And comparing the theoretical optoelectronic intensity ratio with the actual optoelectronic intensity ratio to obtain at least one of a composition ratio of the specific nano thin film and a thickness of the thin film layer.

The present invention enables the composition and structure distribution analysis in the in-situ and non-destructive state without using the photoelectron angular spectroscopic analyzer without exposing the multi-layered thin film material of several nano-thickness of the nano-film in the air. In addition, the present invention may provide a structural analysis and chemical composition analysis results in real time at each step of the deposition process.

Description

Method for analyzing composition and structure of nano thin layer using angle resolved X-ray photoelectron spectroscopy

The present invention is a method for analyzing the composition and structure of a nano thin film using an angular decomposition spectrometer, more specifically using a angular decomposition spectrometer to measure the photoelectron intensity ratio of the nano thin film and apply the intensity ratio to the simulation model in the depth direction A method of analyzing the composition and structure.

In recent years, the development of semiconductor manufacturing process technology has made it possible to manufacture a thin film of a few nanometers thick, it is necessary to secure a technology that can evaluate the composition and multi-layer structure of the nano-thin film of several nanometers thick.

To this end, first, a method using a photoelectron spectroscopy (XPS) for the composition analysis of a thin film having a thickness of several nanometers has been proposed and used for thin film analysis of a single layer structure. In addition, a method of observing a cross section of a nano thin film structure using a transmission electron microscopy (TEM) is mainly used for structural analysis of a nano thin film deposited in multiple layers.

However, in order to observe the cross-section of the thin film structure with a transmission electron microscope for the structure analysis of a conventional nano-layer laminated thin film, a process for separately preparing a specimen for transmission electron microscope analysis is required. However, analytical specimens are time consuming to produce. Moreover, the thin film is often damaged during the preparation of the sample, and when the specimen is exposed to the atmosphere after fabrication, the thin film is contaminated by the surface reaction. In addition, the transmission electron microscope analysis can confirm the thickness distribution of the laminated thin film accurately, but it is impossible to confirm the exact chemical composition distribution of each thin film layer in the multilayer thin film having nano-thickness, and it is impossible to derive the planar average composition of the thin film.

Therefore, the present invention is to solve the problem of the structural analysis of the conventional nano-thin film.

That is, an object of the present invention is to provide a method capable of directly analyzing a deposited thin film (ie, analyzing in an in-situ state) without exposing the deposited thin film to the atmosphere.

Another object of the present invention is to provide a method capable of providing structural analysis and chemical composition analysis results in real time at each step of the deposition process.

In addition, an object of the present invention is to provide a method that can accurately analyze the thickness structure of the nano thin film and the composition distribution of each unit nano thin film without using a transmission electron microscope.

Composition and structure analysis method of the nano thin film according to the present invention for achieving the above object:

Inputting at least one of an arbitrary composition ratio of the nano thin film and a thickness of the thin film layer;

Obtaining a theoretical photoelectron intensity value according to the input arbitrary composition ratio and thickness of the thin film layer;

Obtaining an optoelectronic intensity ratio according to the theoretical optoelectronic intensity value;

Measuring the photoelectron intensity value of the particular nano thin film;

Obtaining an actual photoelectron intensity ratio according to the measured photoelectron intensity value;

Obtaining at least one of a composition ratio of the specific nano thin film and a thickness of the thin film layer by comparing the theoretical optoelectronic intensity ratio with the actual photoelectron intensity ratio

Characterized in that it comprises a.

In addition, in the step of inputting at least one of the arbitrary composition ratio of the nano thin film and the thickness of the thin film layer, it is preferable that a plurality of the arbitrary composition ratio and the thickness of the thin film layer are input.

In addition, in the step of inputting at least one of the arbitrary composition ratio of the nano thin film and the thickness of the thin film layer, the arbitrary composition ratio and the thickness of the thin film layer is preferably determined according to the expected value of the composition ratio of the specific nano thin film and the thickness of the thin film layer. Do.

In addition, the theoretical photoelectron intensity value is preferably calculated using at least one of the following equations:

;

;

.

.

In addition, the photoelectron intensity value of the specific nano thin film is preferably measured using an angular decomposition spectrometer.

In addition, the photoelectron intensity value of the specific nano thin film is preferably measured using an angular decomposition spectrometer.

In addition, the composition and structure analysis system of the nano thin film according to the present invention compares the theoretical photoelectric intensity value of the nano thin film having an arbitrary composition ratio and the thickness of the thin film layer with the actual measured photoelectron intensity value of the specific nano thin film to A computing device for obtaining at least one of a composition ratio and a thickness of the thin film layer, and a database for storing theoretical photoelectron intensity values of the nano thin film having the arbitrary composition ratio and thickness of the thin film layer,

The computing device receives at least one of an arbitrary composition ratio of the nano thin film and a thickness of the thin film layer; Obtaining a theoretical photoelectric strength value according to the input arbitrary composition ratio and thickness of the thin film layer; Obtaining an optoelectronic intensity ratio according to the theoretical optoelectronic intensity value; Measuring the photoelectron intensity of the particular nano thin film; Obtaining an actual photoelectron intensity ratio based on the measured photoelectron intensity value; Compare the theoretical optoelectronic intensity ratio with the actual optoelectronic intensity ratio to obtain at least one of the composition ratio of the specific nano thin film and the thickness of the thin film layer,

The photoelectron intensity value of the specific nano thin film is measured using an angular decomposition spectrometer.

In addition, the theoretical optoelectronic intensity value according to the arbitrary composition ratio and the thickness of the thin film layer is preferably used by extracting the theoretical optoelectronic intensity value stored in a predetermined database.

In addition, in the step of inputting at least one of the arbitrary composition ratio of the nano thin film and the thickness of the thin film layer, it is preferable that a plurality of the arbitrary composition ratio and the thickness of the thin film layer are input.

In addition, in the step of inputting at least one of the arbitrary composition ratio of the nano thin film and the thickness of the thin film layer, the arbitrary composition ratio and the thickness of the thin film layer is preferably determined according to the expected value of the composition ratio of the specific nano thin film and the thickness of the thin film layer. Do.

The invention also preferably includes a computer program product that is run on a computer and includes one or more computer readable media having instructions executable on the computer for performing the composition and structure analysis method of the nano thin film.

The present invention enables the composition and structure distribution analysis in the in-situ and non-destructive state without using the photoelectron angular spectroscopic analyzer without exposing the multi-layered thin film material of several nano-thickness of the nano-film in the air. In addition, the present invention may provide a structural analysis and chemical composition analysis results in real time at each step of the deposition process.

In addition, through this, the qualitative and quantitative analysis technology of the polar surface state is established, and thus it can be applied to the analysis of the surface properties of the constituent materials of the micro system formed of the multi-layer structured thin film.

In particular, modeling that can systematically analyze the thickness and composition of a multilayer structure thin film can be applied to the evaluation of the characteristics of a multilayer high dielectric thin film which is being actively studied, thereby improving stabilization of a process.

With reference to the accompanying drawings, a method of analyzing the composition and structure of the nano-thin film using the angular decomposition spectrometer according to a preferred embodiment of the present invention will be described in detail below.

The present invention relates to a method of determining a structure such as the composition of a nano thin film and the thickness of a thin film layer by comparing the photoelectron intensity ratio value of an arbitrary element measured by an angular spectroscopic analyzer with a theoretical value of the photoelectron intensity of a specific element. That is, the photoelectron intensity of the nano thin film shows a change that decreases as the takeoff angle increases, and the photoelectron intensity of the substrate increases. The relative depth of each bonding component from the comparison of increase and decrease according to the change of takeoff angle of the intensity It is possible to simulate the composition and structure of the nano thin film using the comparison of distributions.

1 is a flow diagram schematically illustrating a procedure for analyzing the composition and structure of a nano thin film according to the present embodiment.

As shown in FIG. 1, first, an expected composition ratio and a thickness of a layer of a nano thin film are input (S102), and a theoretical photoelectron intensity value according to the expected composition ratio and thickness is obtained (S104).

The theoretical value of the photoelectron intensity is calculated as follows.

First, when the structure having a multi-layered thin film layer and composed of one component, the intensity (I) of each photoelectron generated in each layer of the thin film layer can be calculated according to the following equation (1).

Here, I0 is the incident amount per unit area of X-rays irradiated onto the sample, A is the analysis area, and A = A ₀ / sinθ (where A ₀ is the analysis area when θ = 90 °) at a specific takeoff angle θ. Further, σ _a (hυ) is the photoionization cross section of the photoelectrons generated at a specific energy level of a atom by the photon energy (hυ), and D (E _a ) is the detection efficiency of each electron transferred by the electron spectrometer, , L _a (β) is the dependence on the angle of the photoelectron intensity generated from each atom, L _a (β) = 1 + 1/2/2 (3 / 2sin2γ), where γ is the angle between the incident beam and the photon emission direction Where β is asymmetric and has a constant value at a specific energy level of each atom. In this embodiment, a value by Reilman et al. Is used. Also, T (E _a ) is the transmission function of the analyzer for the photoelectrons with energy of E _a , and λ (E _k ) is the inelastic mean free path.

On the other hand, for analysis of a multi-component thin film, when each layer is not composed of a single component and has a constant fraction (X _n ), the intensity of photoelectrons generated in each layer is converted by Equation 2 below.

If the theoretical photoelectron intensity according to the arbitrary composition ratio and thickness is calculated | required (S104), then the photoelectron intensity ratio based on the calculated theoretical photoelectron intensity | strength is calculated | required (S106). For example, assuming a layered structure composed of two compositions, A and B, suppose that the theoretical intensity of component _A is C _A , and the theoretical strength of component _B is C _B. Becomes C _n = C _A / C _B.

When the photoelectron intensity ratio according to the theoretical photoelectron intensity is obtained (S106), the photoelectron intensity value of the nano thin film to be actually measured is directly measured (S108), and then the photoelectron intensity ratio of the nano thin film is calculated (S110).

Specifically, the photoelectron intensity value in this embodiment uses an angle resolved X-ray photoelectron spectroscopy (ARXPS). In addition, the measurement of the actual optoelectronic strength is preferably performed for various takeoff angles.

On the other hand, the method for obtaining the photoelectron intensity ratio using the actually measured photoelectron intensity is as follows.

The photoelectron intensity for the constituent elements of the nano thin film to be measured is measured according to the change in takeoff angle. For example, in the case of a mixed thin film composed of A and B elements, when the photoelectron intensities of the A and B elements in the thin film are measured, the strength of each element is displayed numerically on the graph. In this case, if the measured values of each element are I _A and I _B , the photon intensity ratio can be obtained by performing the arithmetic process of the measured values I _A / I _B.

Finally, by comparing the theoretical photoelectron intensity ratio with the photoelectric intensity ratio of the actual thin film, it is possible to accurately simulate the composition of the components constituting the actual thin film and the thickness of the thin film layer (S112). That is, the photoelectron intensity ratio of the actual nano thin film measured for various takeoff angles can be represented by a graph as described below. The graph of the photoelectron intensity ratio for the real thin film is theoretically obtained for various compositions and thicknesses. After comparing with the graph of the intensity ratio of optoelectronics, the theoretical graphs closest to the actual graphs are selected, and the structure and thickness of the selected theoretical graphs can be checked to accurately understand the structure and thickness information of the actual nano thin film. have.

Experimental Example 1

A method of theoretically calculating the photoelectron intensity for the nano thin films having various structures composed of Al ₂ O ₃ and HfO ₂ will be described below with reference to FIGS. ₂ and ₃ .

First, a sample 21 of Fig. (A) is an Al ₂ O ₃ and HfO ₂ on the Si substrate 1: a diagram showing the case that the mounting is mixed at a ratio of 1: 1. In addition, FIG. 2 (b), which is sample 2, shows a structure in which Al ₂ O ₃ and HfO ₂ are sequentially stacked on a Si substrate, and FIG. 2 (c), which is sample 3, has HfO ₂ on a Si substrate. Since the content of Al ₂ O ₃ increases as the layer is stacked upward, the uppermost layer is a diagram showing a multilayer thin film structure laminated with only Al ₂ O ₃ . In addition, in order to provide theoretical photoelectron intensity values for nano thin films of various thicknesses, Sample 2 and Sample 3 sequentially change the thickness of the thin film at the bottom of the thin film of the structure [1] 1 nm / 1 nm / 1 nm, respectively. / 1 nm / 1 nm, [2] 2 nm / 2 nm / 2 nm / 2 nm / 2 nm, [3] 1 nm / 2 nm / 1 nm / 2 nm / 1 nm, [4] 2 nm / 1 The theoretical intensity ratios were calculated for the case of lamination with nm / 2 nm / 1 nm / 2 nm, respectively.

The theoretical strength ratio (C (Al ₂ O ₃ ) / C (HfO ₂ )) according to various takeoff angles was calculated using the method described in this embodiment for the thin film structure having the thin film structure as shown in FIG. One result is shown in FIG. 3. That is, FIG. 3 (a) shows the results of calculating the strength ratios for the various takeoff angles of Sample 1, and FIG. 3 (b) shows the results of calculating the strength ratios for the various takeoff angles and thicknesses of the thin films. 3 (c) shows the results of calculating the intensity ratios for various takeoff angles of Sample 3. FIG. In addition, the IMFPs of Al2O3 and HfO2 were substituted with 2.88 nm and 2.83 nm, respectively, when Al K _α corresponding to 1486.6 eV was calculated from the kinetic energy of Hf 4f and Al 2p when source energy was used.

Experimental Example  2

Next, specific experimental results of determining the thickness and composition of the thin film nano-film composed of SiO ₂ and La ₂ O ₃ using the method according to the preferred embodiment of the present invention will be described.

First, the thicknesses of the SiO ₂ and La ₂ O ₃ thin films used in this experiment were formed to be 3 nm. In addition, by applying the inelastic mean free path proposed by PJ Cumpson, inelastic mean free path values of 3.7 nm for Si 2p electrons and 2.3 nm for La 4d electrons were applied. Accordingly, first, the theoretical photoelectron intensity ratio for each of the compositions of SiO ₂ and La ₂ O ₃ ranging from 9: 1 to 1: 9 was obtained, and the results are shown in FIG. 4 (a).

Then, the actual strength value for the SiO ₂ / La ₂ O ₃ thin film used in the experiment was measured, and the intensity ratio was calculated. In FIG. 4B, the left graph shows XPS analysis results of La ₂ O ₃ and SiO ₂ mixed thin films deposited on a GaAs substrate. The measured results are obtained in a state in which La, Si, and Ga peaks are mixed, and the analysis can separate regions according to the contribution of each element. The black area on the left graph shows Si 2p and the white area shows the La 4d peak. The intensity ratios of La 4d and Si 2p peaks according to the takeoff angle are as follows and the intensity ratio La 4d / Si 2p can be obtained using these values.

Takeoff angle La 4d photoelectric strength Si 2p Optoelectronic Strength La 4d / Si 2p photoelectric intensity ratio 15 ° 0.659 0.500 1.31 30 ° 0.661 0.473 1.39 45 ° 0.661 0.448 1.48 60 ° 0.661 0.418 1.58 75 ° 0.661 0.411 1.60 90 ° 0.666 0.409 1.63

Through this process, the intensity ratio of the actual measured strength value was calculated and compared with the theoretical value calculated previously. As a result, the actual strength ratio is shown as shown in Figure 4 (b), it can be seen that SiO ₂ and La ₂ O ₃ is composed of 0.45: 0.55.

Next, the composition and structure analysis system of the nano thin film according to the preferred embodiment of the present invention compares the theoretical photoelectric intensity value of the nano thin film having an arbitrary composition ratio and the thickness of the thin film layer with the actual measured photoelectron intensity value of the specific nano thin film And a computing device for obtaining at least one of the composition ratio of the specific nano thin film and the thickness of the thin film layer, and a database for storing theoretical photoelectron intensity values of the nano thin film having the arbitrary composition ratio and thickness of the thin film layer. The computing device may also receive at least one of an arbitrary composition ratio of the nano thin film and a thickness of the thin film layer; Obtaining a theoretical photoelectric strength value according to the input arbitrary composition ratio and thickness of the thin film layer; Obtaining an optoelectronic intensity ratio according to the theoretical optoelectronic intensity value; Measuring the photoelectron intensity of the particular nano thin film; Obtaining an actual photoelectron intensity ratio according to the measured photoelectron intensity value; The theoretical optoelectronic intensity ratio and the actual optoelectronic intensity ratio are operable to obtain at least one of the composition ratio of the specific nano thin film and the thickness of the thin film layer. In addition, in this embodiment, the photoelectron intensity value of the specific nano thin film is measured using an angular decomposition spectrometer. In addition, since each calculation process of the computing device is substantially the same as each step according to the composition and structure analysis method of the nano-thin film according to a preferred embodiment of the present invention will not be described in detail.

In addition, the methods and systems described above are computer programs that include one or more computer readable media running on a computer and having computer executable instructions for analyzing the components and structures of the nano thin films using the methods and / or systems described above. It will be appreciated that it is available as a product. That is, another embodiment of the present invention relates to the implementation of the various embodiments described above of the present invention using hardware and software.

In addition, the computing device or processor may be, for example, a general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other programmable logic device. Various embodiments of the present invention may also be carried out or practiced by a combination of these devices.

In addition, various embodiments of the present invention may also be implemented by software modules, which may be executed by a processor or directly in hardware. In addition, a combination of software modules and hardware implementations may be possible. The software module may be stored in any kind of computer readable storage medium such as, for example, RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROMs, DVDs and the like.

The composition and structure analysis method and system of the nano thin film according to the preferred embodiment of the present invention have been described in detail. However, one of ordinary skill in the art will recognize that various modifications and variations can be made to the embodiment. Therefore, the scope of the present invention is limited only by the claims which will be described later.

1 is a flow diagram schematically illustrating a procedure for analyzing the composition and structure of a nano thin film according to the present embodiment.

FIG. 2 (a) is a view showing a case where Al ₂ O ₃ and HfO ₂ are mixed and mounted on a Si substrate in a ratio of 1: 1, and FIG. 2 (b) shows Al ₂ O ₃ and HfO ₂ on a Si substrate. 2 (c) shows a structure in which HfO ₂ is stacked on a lowermost layer and an Al ₂ O ₃ content increases in an uppermost layer on a Si substrate, and the uppermost layer is a multilayered layer of Al ₂ O ₃ alone. It is a figure which shows a thin film structure.

FIG. 3 (a) shows the results of calculating the strength ratios for the various takeoff angles according to FIG. 2 (a), and FIG. 3 (b) shows the various takeoff angles and thicknesses of the thin films according to FIG. 2 (b). The result of calculating the intensity ratio is shown, and FIG. 3 (c) shows the result of calculating the intensity ratio for various takeoff angles according to FIG. 2 (c).

FIG. 4 (a) is a graph showing the results of measuring theoretical optoelectronic intensity ratios at various takeoff angles according to the ratio of SiO ₂ and La ₂ O ₃ , and FIG. 4 (b) is a SiO ₂ / La ₂ O ₃ thin film. Is a comparison between the actual intensity ratio of and the theoretical optoelectronic intensity ratio shown in FIG.

Claims (10)

Inputting at least one of an arbitrary composition ratio of the nano thin film and a thickness of the thin film layer; Obtaining a theoretical photoelectron intensity value according to the input arbitrary composition ratio and thickness of the thin film layer; Obtaining an optoelectronic intensity ratio according to the theoretical optoelectronic intensity value; Measuring the photoelectron intensity value of the particular nano thin film; Obtaining an actual photoelectron intensity ratio according to the measured photoelectron intensity value; And Obtaining at least one of a composition ratio of the specific nano thin film and a thickness of the thin film layer by comparing the theoretical optoelectronic intensity ratio with the actual photoelectron intensity ratio Composition and structure analysis method of the nano-thin film comprising a. The composition and structure analysis of the nano thin film according to claim 1, wherein in the step of inputting at least one of an arbitrary composition ratio of the nano thin film and a thickness of the thin film layer, a plurality of the arbitrary composition ratio and the thickness of the thin film layer are input. Way. The method of claim 1 or 2, wherein the step of inputting at least one of the arbitrary composition ratio of the nano thin film and the thickness of the thin film layer, the arbitrary composition ratio and the thickness of the thin film layer is expected of the composition ratio of the specific nano thin film and the thickness of the thin film layer. Composition and structure analysis method of a nano thin film, characterized in that determined according to the value. The method of claim 1 or 2, wherein the theoretical photoelectron intensity value is calculated using at least one of the following equations:

;

. The method of claim 1 or 2, wherein the photoelectron intensity value of the specific nano thin film is measured using an angular decomposition spectroscopic analyzer. A computing device for obtaining at least one of the composition ratio of the specific nano thin film and the thickness of the thin film layer by comparing the theoretical photoelectron intensity value of the nano thin film having an arbitrary composition ratio and the thickness of the thin film layer with the actual measured photoelectron intensity value of the specific nano thin film; A database for storing theoretical photoelectron intensity values of the nano thin film having an arbitrary composition ratio and thickness of the thin film layer, The computing device receives at least one of an arbitrary composition ratio of the nano thin film and a thickness of the thin film layer; Obtaining a theoretical photoelectric strength value according to the input arbitrary composition ratio and thickness of the thin film layer; Obtaining an optoelectronic intensity ratio according to the theoretical optoelectronic intensity value; Measuring the photoelectron intensity of the particular nano thin film; Obtaining an actual photoelectron intensity ratio according to the measured photoelectron intensity value; Compare the theoretical optoelectronic intensity ratio with the actual optoelectronic intensity ratio to obtain at least one of the composition ratio of the specific nano thin film and the thickness of the thin film layer, The photoelectron intensity value of the particular nano thin film is a nano-film adjustment and structure analysis system, characterized in that measured using an spectral analyzer. The system of claim 6, wherein the theoretical photoelectron intensity value according to the arbitrary composition ratio and the thickness of the thin film layer is extracted by using a theoretical photoelectron intensity value stored in a predetermined database. According to claim 6 or 7, wherein in the step of inputting at least one of the arbitrary composition ratio of the nano thin film and the thickness of the thin film layer, the adjustment of the nano thin film, characterized in that a plurality of the arbitrary composition ratio and the thickness of the thin film layer is input. And structural analysis system. The method of claim 6 or 7, wherein the inputting at least one of the arbitrary composition ratio of the nano thin film and the thickness of the thin film layer, wherein the arbitrary composition ratio and the thickness of the thin film layer is expected of the composition ratio of the specific nano thin film and the thickness of the thin film layer. System for the adjustment and structure analysis of nano thin films, characterized in that determined according to the value. A computer program product running on a computer, the computer program product comprising one or more computer readable media having instructions executable on the computer for carrying out the method according to claim 1.

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