JP2000314689A - Method for preparing sample for analyzing impurities in depth direction of alumina sintered body and impurity analyzing method using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing a sample capable of analyzing impurities in the depth direction of an alumina sintered body to easily and highly accurately determine the same without generating pollution and an impurity analyzing method using the same. SOLUTION: In a method for forming a sample for analyzing impurities in the depth direction of an alumina sintered body, an alumina sintered body analyzing sample and sulfuric acid are housed in a pressure decomposing container to etch a predetermined amt. of the analyzing sample by pressure decomposition and sulfuric acid after etching is recovered. The etching of a predetermined amt. of the analyzing sample and the recovery of sulfuric acid after etching are performed repeatedly and this recovered sulfuric acid is used as an impurity analyzing sample. This analyzing sample is used to analyze impurities of the alumina sintered body by a high sensitivity analyzing method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a sample for impurity analysis in the depth direction of an alumina sintered body and an impurity analysis method using the same, and more particularly, to an alumina sintered body easily and accurately. The present invention relates to a method for preparing a sample for analyzing impurities in a depth direction of an alumina sintered body capable of analyzing impurities in a depth direction, and an impurity analysis method using the same.

[0002]

2. Description of the Related Art Conventionally, alumina-based sintered bodies have been used as semiconductor processing members because of their excellent heat resistance, high purity and strength, and alumina-based porous bodies have been used for filters and the like. .

However, in recent years, the degree of integration of semiconductor devices has been advanced, and the demand for high purity of semiconductor wafer processing members has become strict, and the alumina sintered body has also been required to have high purity.

[0004] In order to meet the demand for higher purity, it is necessary to control the impurity content by measuring impurities in the depth direction of the alumina sintered body used for the semiconductor processing member.

Regarding the method of chemical analysis of alumina, see JCRS 104-1993, "Chemical analysis method of alumina fine powder for fine ceramics", Japan Ceramic Association.
The alumina fine powder analysis sample is put into a resin container of a pressure decomposition container, and the whole sample is decomposed with a reagent such as sulfuric acid.
The decomposed sample solution is analyzed by ICP-emission spectroscopy. In this analysis method, the amount of metal impurities contained in the alumina fine powder analysis sample can be quantified, but the amount of metal impurities in the depth direction (for each layer) of the sample cannot be quantified, and powder is used as the analysis sample. Therefore, a problem of contamination occurs in the pulverizing step.

JIS R6123-1995 “Chemical analysis method of alumina-based abrasive” describes that an alumina-based abrasive is put into a platinum crucible, and the whole sample is decomposed with a reagent.
This decomposed sample solution is analyzed by molybdenum yellow absorption spectrophotometry. With this analysis method, the amount of metal impurities contained in the alumina-based abrasive analysis sample can be quantified, but the amount of metal impurities in the depth direction of the sample cannot be quantified,
Further, preparation of an analysis sample for high-sensitivity analysis is not suitable for quantification of trace impurities.

Japanese Patent Application Laid-Open No. 5-256744 discloses a method of analyzing a sample in the depth direction by irradiating a laser beam to the surface of the sample and sequentially collecting the sample from the surface toward the inside. An analysis method for performing a depth direction analysis is described. Since this analysis method uses a laser beam, it requires a large-scale apparatus, it is difficult to prepare a sample easily, and there is a possibility that the sample may be contaminated when a molten sample is collected.

[0008]

SUMMARY OF THE INVENTION Therefore, a depth-wise impurity analysis of an alumina sintered body capable of analyzing impurities in a depth direction of the alumina sintered body easily and without contamination and capable of quantitatively determining impurities with high precision. There has been a demand for a method for preparing a sample for use and an impurity analysis method using the same.

The present invention has been made in view of the above circumstances, and is an alumina sintered body capable of analyzing impurities in the depth direction of an alumina sintered body that is easy, free of contamination, and capable of quantifying impurities with high precision. It is an object of the present invention to provide a method for preparing a sample for impurity analysis in the depth direction and a method for analyzing impurities using the same.

[0010]

Means for Solving the Problems According to the first aspect of the present invention, which has been made to achieve the above object, an alumina-based sintered body analysis sample and sulfuric acid are housed in a pressure decomposition vessel, and a predetermined amount is decomposed by pressure decomposition. An alumina sample characterized by etching an analysis sample, collecting sulfuric acid after etching, and repeatedly etching a predetermined amount of the analysis sample and collecting sulfuric acid after etching, and using each of the collected sulfuric acid as an analysis sample. The gist is to provide a method for producing a sample for impurity analysis in the depth direction of a porous sintered body.

According to the second aspect of the present invention, the etching of the predetermined amount of the analysis sample is determined by a pressure decomposition time and a pressure temperature. The gist is to provide a method for preparing a sample for impurity analysis in the vertical direction.

The invention according to claim 3 of the present invention is characterized in that the inner container in which the sample for alumina-based sintered body and the sulfuric acid of the pressure decomposition vessel are stored is made of PFA.
Or the method of preparing a sample for analyzing impurities in the depth direction of the alumina-based sintered body described in 2 above.

According to the invention of claim 4 of the present application, the alumina-based sintered body analysis sample and sulfuric acid are stored in a pressure decomposition vessel, a predetermined amount of the analysis sample is etched by pressure decomposition, and the sulfuric acid after the etching is recovered. A predetermined amount of an analytical sample is repeatedly etched and sulfuric acid after the etching is collected, and the sulfuric acid after the etching is quantitatively determined by a high-sensitivity analysis method using each of the collected sulfuric acids. The gist is that it is an analysis method.

In the invention of claim 5 of the present application, the high-sensitivity analysis method is plasma emission analysis or flameless atomic absorption spectroscopy, and the depth of the alumina-based sintered body according to claim 4 is characterized in that: The gist is that it is a method for analyzing impurities in one direction.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for preparing a sample for impurity analysis in the depth direction of an alumina sintered body according to the present invention and an impurity analysis method using the same will be described with reference to the accompanying drawings.

The amount of impurities in the depth direction of the alumina sintered body is measured, for example, by preparing a sample for impurity analysis by a method having a process as shown in FIG.

For example, an alumina sintered body as a sample and sulfuric acid (1 + 3) as a solvent are prepared and stored in a pressure decomposition vessel 2 having a PFA inner vessel 1 as shown in FIG. The alumina sintered body is etched by a predetermined amount (predetermined depth) by pressure decomposition for a time, and after cooling, the sulfuric acid used for the etching is recovered and fixed in volume to prepare a sample for high sensitivity analysis. The heating time and the amount of etching in the depth direction of the alumina sintered body show a tendency as shown in FIG. 3, and the amount of dissolution can be generally adjusted by the heating temperature and the heating time.

Further, sulfuric acid as a solvent is put into the inner vessel 1 in which the alumina sintered body of the sample is left, and the alumina sintered body is etched by a predetermined amount by pressure decomposition at a predetermined temperature for a predetermined time, followed by cooling. Thereafter, the sulfuric acid used for the etching is recovered, and the volume is fixed to prepare a sample for high sensitivity analysis.

By repeating the cycle of pressure decomposition and constant volume a plurality of times, an analytical sample for high sensitivity analysis of impurities is obtained in each depth direction (layer) of the alumina sintered body.

Next, a method of analyzing impurities in the depth direction of the alumina sintered body according to the present invention will be described.

As shown in FIG. 4, according to a high-sensitivity analysis method, for example, inductively coupled plasma emission spectrometry (ICP-AES), ICP-AES is used for quantification of a trace amount of a metal element contained in an analysis sample. The purpose is to examine the qualitative properties of a specific element from the wavelength of a signal emitted from atoms or ions excited by inductively coupled plasma, and to quantify the element from the intensity of the signal.

For example, the analysis sample s is introduced into the inductively coupled plasma 12 through the nebulizer 11. The elements in the sample s are excited by the inductively coupled plasma 12 and emit a luminescent signal. This emission signal is transmitted from the entrance slit 13 to the mirror 15
6. The light is guided to the exit slit 18 by the mirror 17 and output. The photomultiplier tube 19 detects this output signal, amplifies the detected signal with an amplifier 20, and
1 and a signal is sent to the data processing unit 22 to perform data processing.

By using such ICP-AES, Mg, Si, Ca, Ti, Cr, Fe, Ni, Cu
Can be measured with high sensitivity.

Further, as shown in FIG.
For example, according to the flameless atomic absorption method (FLAA),
FLAA dissociates into atomic vapors by an electric heating method and guides light from a light source (such as a hollow cathode discharge tube) to this,
The light intensity of a specific monochromatic resonance line is measured. Since the absorbance is proportional to the atomic density of the target metal element in the sample, the concentration in the analysis sample is determined from this.

For example, 5 to 50 μl of an analysis sample (liquid) s is injected into a small hole of a tubular graphite furnace 32 with a micropipette 31 and a very small amount of the analysis sample s is injected from the electrode 33 to the graphite furnace 3.
The sample (liquid) s is completely vaporized by Joule heat generated by passing an electric current through the sample 2. Irradiation light 35 emitted from the light source of the hollow cathode tube 34 is irradiated to the atomized state in the graphite furnace 32, reaches the detector 37 via the spectroscope 36, and the light absorption is measured by the detector 37. You. Next, the absorbance is output to the display unit 39 via the signal processing unit 38.
The absorption signal appears immediately after atomization and its peak value or integrated value is recorded. Since the absorbance signal intensity is proportional to the concentration of the metal element in the analysis sample s, the quantitative analysis of the metal element is performed using this relationship as a calibration curve for the standard solution.

By using FLAA in this way, N
The content of impurities a and K can be measured with high sensitivity.

[0027]

Example (1) Investigation of Test 1 Recovery Yield A solution containing 1 ng of each metal element was placed in a pressure decomposition vessel as shown in FIG. 2 and heated at 230 ° C. for 16 hours. , FLAA and the recovery of each metal element was investigated. Table 1 shows the average value of the results of performing the same test five times.

[0028]

[Table 1]

A recovery rate of about 100% was obtained for each element, and it was confirmed that each impurity metal element could be almost completely recovered.

(2) Test 2 Repeatability The same test as the above (1) was performed 10 times (5 times for Na and K), and the ratio of run-out was investigated.

Table 2 shows the test results.

[0032]

[Table 2]

(3) Test 3 Quantitative limit of sample preparation method Five blank tests were performed, and 3σ of the measured value was converted to concentration to determine the quantification limit. Table 3 shows the results.

[0034]

[Table 3]

(4) Test 4 Actual sample test The alumina sintered body (diameter 20 mm x length 30 mm) and sulfuric acid were put in a PFA container (capacity 23 ml) of a pressure decomposition container as shown in FIG. The etching was repeated 9 times at 230 ° C. for 16 hours per etching, and the sulfuric acid after the etching was recovered, fixed in volume, and analyzed by plasma emission analysis and atomic absorption spectroscopy to find the depth of the alumina-based sintered body. The amount of each metal element contained in the direction (for each layer) was determined. Table 4 shows the quantitative results.

[0036]

[Table 4]

[0037]

According to the method for preparing a sample for analyzing impurities in the depth direction of an alumina sintered body according to the present invention, the analysis of impurities in the depth direction of the alumina sintered body can be performed with high accuracy. A method for producing a sample for analyzing impurities in the depth direction of an alumina sintered body, which can perform the above, can be provided.

That is, a predetermined amount of the analytical sample is repeatedly etched and sulfuric acid after the etching is recovered, and the recovered sulfuric acid is used as an analytical sample, whereby an impurity analysis sample in the depth direction of the alumina sintered body can be easily and easily obtained. It can be manufactured without contamination.

Further, since the etching of a predetermined amount of the analysis sample is determined by the pressure decomposition time and the pressure temperature, the amount of dissolution of the alumina-based sintered body in the depth direction can be easily adjusted, and each depth (layer) can be adjusted. 2) An analysis sample can be easily prepared.

Since the alumina-based sintered body analysis sample of the pressure decomposition vessel and the inner container containing sulfuric acid are made of PFA, an analysis sample without contamination can be prepared.

Further, since the quantitative determination is performed by the high sensitivity analysis method using the analytical sample prepared by the method for preparing a sample for impurity analysis in the depth direction of the alumina sintered body according to the present invention, the alumina sintered body is highly sensitive. Of impurities in the depth direction of the substrate.

Since the high sensitivity analysis is performed by plasma emission analysis or flameless atomic absorption spectroscopy,
Impurity analysis in the depth direction of the alumina sintered body can be performed with higher sensitivity.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a method for producing a sample for impurity analysis in the depth direction of an alumina sintered body according to the present invention and the steps of an impurity analysis method using the same.

FIG. 2 is a cross-sectional view of a pressurized decomposition vessel used in a method for producing a sample for impurity analysis in a depth direction of an alumina sintered body according to the present invention.

FIG. 3 is an explanatory view showing a relationship between an etching time and an etching amount in a method for manufacturing a sample for impurity analysis in a depth direction of an alumina sintered body according to the present invention.

FIG. 4 is a conceptual diagram of a plasma emission analysis method used for analyzing impurities in a depth direction of an alumina sintered body according to the present invention.

FIG. 5 is a conceptual diagram of flameless atomic absorption spectroscopy used for analyzing impurities in a depth direction of the alumina sintered body according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PFA inner container 2 Pressurized decomposition vessel 11 Nebulizer 12 Inductively coupled plasma 13 Inlet slit 14 Spectroscopic part 15 Mirror 16 Grating 17 Mirror 18 Outlet slit 19 Photomultiplier tube 20 Amplifier 21 Recorder 22 Data processing part 31 Micropipette 32 Graphite furnace 33 Electrode 34 Hollow cathode tube 35 Irradiation light 36 Spectrometer 37 Detector 38 Signal processing unit 39 Display unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G042 AA01 BA20 BC01 BC02 BC04 BC06 BC08 BC10 CA04 CB06 DA10 EA03 FA01 FB02 GA01 GA02 HA02 HA05

Claims (5)

[Claims] 1. An alumina-based sintered body analysis sample and sulfuric acid are housed in a pressure decomposition vessel, a predetermined amount of the analysis sample is etched by pressure decomposition, the sulfuric acid after the etching is recovered, and a predetermined amount of the analysis sample is repeatedly repeated. A method for producing a sample for impurity analysis in the depth direction of an alumina-based sintered body, characterized in that etching of sulfuric acid and recovery of sulfuric acid after etching are performed, and each of the recovered sulfuric acid is used as an analysis sample. 2. The method for analyzing impurities in a depth direction of an alumina sintered body according to claim 1, wherein the predetermined amount of etching of the analysis sample is determined by a pressure decomposition time and a pressure temperature. Sample preparation method. 3. The alumina-based sintered body according to claim 1, wherein the container for storing the sample for analysis of the alumina-based sintered body and sulfuric acid in the pressure decomposition vessel is made of PFA. Of preparing a sample for impurity analysis in the depth direction of the sample. 4. An alumina-based sintered body analysis sample and sulfuric acid are housed in a pressure decomposition vessel, a predetermined amount of the analysis sample is etched by pressure decomposition, sulfuric acid after the etching is collected, and a predetermined amount of the analysis sample is repeated. And analyzing the sulfuric acid after the etching, and quantifying the sulfuric acid using the collected sulfuric acid by a high-sensitivity analysis method. 5. The method for analyzing impurities in a depth direction of an alumina-based sintered body according to claim 4, wherein the high-sensitivity analysis is plasma emission analysis or flameless atomic absorption spectroscopy.