JP2002257757A - Fluorescent x-ray spectrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent X-ray spectrometer quickly accurately analyzing the thickness or the composition of a thin film in each layer of a multi-layer thin film sample. SOLUTION: This fluorescent X-ray spectrometer is equipped with an analytical result memory means 11 storing an analytical result until a specified laminating step every sample 3; an analytical result retrieving means 12 retrieving an analytical result until a previous step of the sample 3 based on the name of the sample from the analytical result stored in the analytical result memory means 11; and a data processing means 13 analyzing the thickness or the composition of the thin film laminated in the latest step based on the measured intensity in the latest step and the analytical result until the previous step retrieved with the analytical result retrieving means 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluorescent X-ray for measuring the intensity of a secondary X-ray generated by irradiating a so-called multilayer thin film sample with a primary X-ray and analyzing the thickness or composition of the thin film of each layer. The present invention relates to an analyzer.

[0002]

2. Description of the Related Art For a so-called multilayer thin film sample formed by laminating multilayer thin films such as a semiconductor wafer and a DVD-RAM, the thickness and composition of each thin film can be determined by X-ray fluorescence analysis. In many cases, when the same component is contained in different layers, or when there is a thick layer that absorbs fluorescent X-rays from the lower layer, etc., it is difficult or impossible to obtain all layers in one analysis. It is.

[0003] In such a case, in a process in which a sample is repeatedly produced by lamination, primary X-rays are emitted at each predetermined stage of laminating one or more thin films. The intensity of secondary X-rays generated by the irradiation is measured, and the thickness and the like of the thin film laminated at the latest stage are obtained based on the measured intensity and the analysis results up to the previous stage. That is, each time a single-layer or multiple-layer thin film that can be analyzed at one time is laminated, the measured intensity at the stage after the lamination and the analysis result (thickness of the thin film, etc.) up to the stage before the lamination are obtained. Based on this, the thickness or the like of a single layer or a plurality of thin films laminated at the latest stage is obtained. Here, conventionally, the analysis results up to the previous stage (analysis results at all stages before the latest stage)
Is manually input to the fluorescent X-ray analyzer by the operator. Of course, in the first stage, there is no analysis result up to the previous stage, and there is no need for manual input.

[0004]

However, it takes a long time to perform lamination between each stage, and it is difficult to find out the analysis results up to the previous stage and manually input the results to a fluorescent X-ray analyzer for a large number of samples. It is complicated and error-prone. This does not allow sufficiently quick and accurate analysis of the multilayer thin film sample.

The present invention has been made in view of the above-mentioned conventional problems, and has been developed in consideration of irradiation of primary X-rays to a multilayer thin film sample.
An object of the present invention is to provide a fluorescent X-ray analyzer for measuring the intensity of the next X-ray and analyzing the thickness or composition of the thin film of each layer, which can perform sufficiently quick and accurate analysis.

[0006]

In order to achieve the above object, an apparatus according to the present invention comprises a sample formed by laminating a multi-layer thin film at a predetermined stage of laminating one or more thin films. Then, the intensity of the secondary X-ray generated by irradiating the primary X-ray is measured, and the thickness or composition of the thin film laminated at the latest stage is analyzed based on the measured intensity and the analysis result up to the previous stage. The X-ray fluorescence analyzer includes the following analysis result storage means, analysis result search means, and data processing means. The analysis result storage means stores the analysis results that have been analyzed up to each stage for each sample. The analysis result retrieval means retrieves, based on the input sample name, an analysis result up to the previous stage of the sample from the analysis result stored in the analysis result storage means. The data processing means analyzes the thickness or composition of the thin film laminated at the latest stage based on the measured intensity at the latest stage and the analysis result up to the previous stage searched by the analysis result search means.

[0007] In the device of the present invention, with such a configuration,
When the operator inputs the name of the sample to be analyzed, the instrument automatically searches the stored analysis results up to the previous stage of the sample and uses it for analysis, so that the multilayer thin film sample is sufficiently quick and accurate. Analysis.

In the apparatus of the present invention, it is preferable that the storage in the analysis result storage means, the search in the analysis result search means and the analysis in the data processing means are further performed for each measurement position in each sample.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus according to an embodiment of the present invention will be described below. First, the configuration of this device will be described with reference to FIG. First, a primary X-ray is transmitted from an X-ray source 1 such as an X-ray tube to a sample 3 formed by laminating a multi-layer thin film at a predetermined stage of laminating one or a plurality of thin films. 2 such as fluorescent X-rays
This is a fluorescent X-ray analyzer that measures the intensity of the next X-ray 4 by the detecting means 9 and analyzes the thickness or composition of the thin film laminated at the latest stage based on the measured intensity and the analysis results up to the previous stage. Here, "thickness or composition" includes "thickness and composition", that is, the case where both thickness and composition are analyzed (the same applies hereinafter). The detecting means 9 detects 2 generated from the sample 3
It includes a spectroscopy element 5 for separating the secondary X-rays 4 and a detector 7 for measuring the intensity of the secondary X-rays 6 split by the spectroscopy element 5.

This apparatus has the following analysis result storage means 11
And an analysis operation means 10 including an analysis result search means 12 and a data processing means 13. The analysis result storage means 11 stores the analysis results analyzed up to each stage for each sample 3. The analysis result search means 12 searches the analysis results of the sample 3 up to the previous stage from the analysis results stored in the analysis result storage means 11 based on the input sample name. The data processing means 13 analyzes the thickness or composition of the thin film laminated at the latest stage based on the measured intensity at the latest stage and the analysis results up to the previous stage searched by the analysis result searching means 12. The analysis result storage means 11 and the analysis result search means 12 are installed separately from other parts of the X-ray fluorescence analyzer (the apparatus body, the data processing means 13, a measurement position control means 14 described later, etc.) and communicate with each other. You may connect by a line.

The data processing means 13 converts the intensity of the fluorescent X-ray 4 measured by the detecting means 9 into a theoretical intensity scale based on the measured intensity and the thickness or composition (content) of each thin film of the sample 3. The theoretical intensity of the fluorescent X-rays calculated assuming is compared for each corresponding component, so that both intensities match.
The thickness or composition of each thin film assumed is corrected and calculated by successive approximation to calculate the thickness or composition of each thin film. That is, this apparatus is an X-ray fluorescence analyzer that performs analysis by the FP method (fundamental parameter method).

In this apparatus, the storage in the analysis result storage means 11, the search in the analysis result search means 12, and the analysis in the data processing means 13 are further performed.
The measurement is performed for each measurement position in each sample 3. That is, the sample 3 is placed on a moving unit such as an rθ stage 8 and is moved relative to the detecting unit 9 so that the sample 3 has a disk shape as shown in FIG. A first measurement position A1 (r = 0, θ = 0), which is the center of the three surfaces, and a second measurement position A2 (r = 20,
θ = 0), the third counterclockwise 90 degrees away from the second measurement position
A measurement position A3 (r = 20, θ = 90) and a fourth measurement position A4 (r = 20, θ = 18) further separated by 90 degrees counterclockwise
0), and a fifth measurement position A5 further separated by 90 degrees counterclockwise.
The measurement is performed at five measurement positions (r = 20, θ = 270), and the analysis of the thickness or the composition of each thin film is also performed for each measurement position. As described above, the measurement position control means 14 for driving the rθ stage 8 to change the measurement position is also included in the analysis calculation means 10.

Next, as for the operation of the apparatus of this embodiment, as shown in FIG.
Sample 3 for forming three thin films 3a, 3b and 3c of i and Cr
In the following, a case where the thickness of each thin film is analyzed will be described as an example. In this sample 3, since the same element Cr is contained in the first layer 3a and the third layer 3c, all the layers 3a, 3b, 3c are analyzed by one analysis when the third layer 3c is stacked.
It is difficult to determine the thickness for. Therefore, the following analysis conditions 1 and 2 are created in advance and analyzed in two stages.

First, under the analysis condition 1, the first layer 3a and the second
At the stage when the layer 3b is laminated, the sample 3 is placed on the rθ stage 8 (FIG. 1) at a predetermined position and in a predetermined direction and irradiated with the primary X-ray 2 to thereby produce the Cr-Kα ray generated from the first layer 3a. 4a and the intensity of the Ni-Kα ray 4b generated from the second layer 3b are respectively measured, and based on the measured intensities, the data processing means 13 (FIG. 1) performs the FP method on the first and second layers. The thickness of each of the thin films 3a and 3b is determined.

In particular, in the apparatus of this embodiment, a sample name of the sample 3 (for distinguishing a plurality of samples, a number or the like may be used) from input means (not shown). When the analysis is performed under the analysis condition 1 and input to the analysis operation means 10 (FIG. 1), the first to fifth measurement positions A1 to A5 are controlled by the measurement position control means 14 (FIG. 1). Each thin film 3 for each A5 (FIG. 2)
The thicknesses a and 3b are obtained, and the obtained thickness is automatically stored in the analysis result storage means 11 (FIG. 1) as an analysis result in the first stage for each measurement position in the sample name. You. When analyzing another sample of the same type, the analysis under the analysis condition 1 is repeated.

Next, after the sample 3 is discharged from the rθ stage 8 (FIG. 1) and the third layer 3c is laminated in the production process, the sample 3 is again transferred to the rθ stage 8 (FIG. 1) under the analysis condition 2. Is placed at a predetermined position and in a predetermined direction, and is irradiated with primary X-rays 2 to generate Cr-K generated from the first layer 3a and the third layer 3c.
The intensities of α rays 4a and 4c (separable and undetectable) are measured, and the data processing unit 13 is operated based on the measured intensity and the analysis result in the first stage (the thickness of the first layer 3a and the second layer 3b). The thickness of the third thin film 3c is determined by the FP method (FIG. 1).

In particular, in the apparatus of this embodiment, when the analysis means 10 of FIG. By the control, the intensity of the Cr-Kα ray 4 is measured for each of the first to fifth measurement positions A1 to A5 (FIG. 2). In response, the analysis result search means 1
2 is a measurement position A1 based on the input sample name.
For each of .about.A5 (FIG. 2), the analysis result of the sample 3 in the first stage is retrieved from the analysis result stored in the analysis result storage unit 11. The data processing means 13 also has measurement positions A1 to A
5 (FIG. 2), the measured intensity of the Cr—Kα ray 4 in the second stage and the first
Based on the analysis result of the thickness of the thin films 3a and 3b (FIG. 3) at the stage, the thickness of the thin film 3c (FIG. 3) laminated at the second stage is analyzed. When analyzing another sample of the same type, the analysis under the analysis condition 2 is repeated.

Even if the number of stages increases, the analysis result storage means 11
Also stores the analysis date and time, and the analysis result search means 12
By retrieving the most recently memorized group of analysis results,
Can be dealt with similarly. For example, in the second stage, not only the analysis results analyzed up to the second stage, that is, the analysis results in the second stage (thickness of the thin film 3c), but also the analysis results in the first stage used to obtain it. (Thicknesses of the thin films 3a and 3b) are also stored, and in the analysis at the third stage, the latest, that is, the analysis results at the second and first stages stored at the second stage are retrieved. Further, the case where the thickness of each layer is obtained in a sample in which each layer is composed of one element has been described as an example. However, the case where each layer contains a plurality of elements and the case where the composition of each layer is obtained can be similarly handled. .

As described above, in the device of this embodiment,
When the operator inputs the name of sample 3 to be analyzed,
Since the apparatus automatically retrieves the analysis results of the sample 3 up to the previous stage from the stored data and uses it for analysis, there is no need to manually input the analysis results up to the previous stage, and the multilayer thin film sample is sufficiently fast. Accurate analysis can be performed. Furthermore, in the case where analysis is performed at a plurality of measurement positions for one sample, manual input becomes more complicated in the past, but this device also supports analysis at a plurality of measurement positions. Quick and accurate analysis. When the measurement position in the sample 3 is fixed to one place, the above-described intensity measurement of the fluorescent X-ray 4, the storage in the analysis result storage unit 11, the search in the analysis result search unit 12, and the analysis in the data processing unit 13 Is sufficient for each sample 3.

[0020]

As described above in detail, according to the present invention, the intensity of secondary X-rays generated by irradiating a primary X-ray to a multilayer thin film sample is measured, and the thickness or the thickness of the thin film of each layer is measured. In a fluorescent X-ray analyzer for analyzing the composition, sufficiently rapid and accurate analysis can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an X-ray fluorescence analyzer according to one embodiment of the present invention.

FIG. 2 is a plan view showing an example of a plurality of measurement positions on a sample by the same device.

FIG. 3 is a side view showing an example of a layer structure of a sample to be analyzed by the same device.

[Explanation of symbols]

2 ... primary X-ray, 3 ... sample, 3a, 3b, 3c ... thin film, 4
... secondary X-ray, 11 ... analysis result storage means, 12 ... analysis result search means, 13 ... data processing means.

Claims (2)

[The claims] An intensity of a secondary X-ray generated by irradiating a primary X-ray to a sample formed by laminating a multi-layer thin film at each predetermined stage of laminating one or a plurality of thin films. X-ray fluorescence analyzer that measures the thickness and composition of the thin film laminated at the latest stage based on the measured intensity and the analysis results up to the previous stage. Analysis result storage means for storing results, analysis result search means for searching, based on the input sample name, analysis results up to the previous stage of the sample from the analysis results stored in the analysis result storage means, Data processing means for analyzing the thickness or composition of the thin film laminated at the latest stage based on the measured intensity at the latest stage and the analysis results up to the previous stage searched by the analysis result search means. Features X-ray fluorescence analyzer. 2. The X-ray fluorescence analyzer according to claim 1, wherein the storage in the analysis result storage unit, the search in the analysis result search unit, and the analysis in the data processing unit are further performed for each measurement position in each sample.