JP2003075408A - Method and apparatus for analysis of metal element in solid sample - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an analytical method for a metal element in a solid sample in which a sample aerosol is generated easily and in which the constitution of an analyzer is simple and to provide the analyzer for the analytical method. SOLUTION: In the analytical method for the metal element in the solid sample, the solid sample S is heated inside a furnace 3, a metal component discharged from the solid sample S is introduced into an inductively coupled plasma mass spectrometer 1 together with a carrier gas, and the metal element is analyzed. The analyzer is used for the analytical 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 analyzing a metal element in a solid sample and a device for analyzing the metal element in the solid sample, and more particularly to a method for analyzing a metal element capable of directly forming a sample aerosol from the solid sample and an apparatus for analyzing the metal element. .

[0002]

2. Description of the Related Art Metal contamination generated in a heat treatment process in semiconductor manufacturing is considered to be one of the causes of release of metal from various members at high temperatures. The relationship between the temperature and atmosphere and the release amount is estimated by diffusion rate and thermodynamic calculation from actual measurement results such as metal profile analysis before and after using various members and analysis of contamination amount on a semiconductor wafer.

However, the method of estimating by such a calculation involves many assumptions such as the behavior in the solid and the state of existence on the surface, and is likely to cause an error.
In addition, since there was no means to actually confirm the calculation result of the release behavior, it was not possible to confirm how much error was included. Furthermore, when the method by calculation is used, in addition to the problem of reliability, actual measurement for calculation requires chemical analysis, transcription test, etc., which consumes a lot of time. Especially when performing a transfer test, members such as a furnace, a core tube, and a boat are required, and a huge cost is required.

Further, as a powerful method for analyzing the metal content contained in various members, inductively coupled plasma mass spectrometry (Inductively Coupled Pla) is used.
sma Mass Spectrometer: ICP-
MS).

In the conventional ICP-MS, as shown in FIG. 6, a sample is dissolved in a solution contained in a container 31, the pump 32 supplies the solution to a nebulizer 33, and the sample is separated by argon gas. Then, a sample aerosol is generated. The sample aerosol is sent to the ICP section 34, where it is desolvated, atomized, and ionized. The sample ions thus obtained are differentially evacuated from the atmospheric pressure plasma in the interface unit 3.
After that, it is transferred to the MS section 38 which is located in the vacuum chamber 36 and which is equipped with the electron multiplication type detector 37. These sample ions pass through two orifices in the interface section 35 to separate the sample ions based on their mass / charge ratio and then analyzed by the electron multiplier detector 37. Each isotope appears in a different mass position with a peak intensity that is directly proportional to the initial concentration of that isotope in the sample. In this way, the elemental concentration in the sample is analyzed.

However, in the conventional ICP-MS, the sample is housed in the container 31, dissolved in the solution, and is supplied to the nebulizer 33 by the pump 32 to form the sample aerosol (fumes). Is required to be dissolved (liquid sample) in a solution, and its handling is troublesome,
Moreover, there is a problem that the device becomes complicated.

[0007] Another effective method for analyzing the metal content contained in various members is the flameless atomic absorption method. This flameless atomic absorption method uses the phenomenon that light is attenuated in proportion to the amount of atomic vapor when a component in a sample is atomized into vapor and the atomic vapor is irradiated with light of a specific wavelength (atomic absorption wavelength). The amount of atomic vapor is obtained by analyzing the attenuation ratio of the light intensity passing through the vapor layer from the light intensity before passing through the vapor layer. Even in this conventional flameless atomic absorption method, although there is an example of direct analysis of impurities in powder such as slurry, the apparatus is optimized on the assumption that a solution is introduced (several tens μl), and solid materials such as semiconductor members are There is no direct observation of the metal emitted from the.

[0008]

Therefore, there has been a demand for a method for analyzing a metal element of a solid sample and a analyzer for the same, which enables a direct analysis of a metal element from a solid sample and has a simple detector structure.

The present invention has been made in consideration of the above-mentioned circumstances, and provides a method for analyzing a metal element of a solid sample and an analysis apparatus therefor, which enables direct analysis of a metal element from a solid sample and has a simple analyzer structure. The purpose is to do.

[0010]

In order to achieve the above object, the invention of claim 1 of the present application is to heat a solid sample in a furnace and inductively couple a metal component released from the solid sample together with a carrier gas. The gist of the present invention is a method for analyzing a metal element of a solid sample, which is characterized in that the metal element is introduced into a plasma mass spectrometer to analyze the metal element.

According to the second aspect of the present invention, a solid sample is heated in a furnace, and the metal atoms released from the solid sample are introduced into a flameless atomic absorption spectrometer to analyze the metallic element in an atomic state. The gist is that it is a method for analyzing a metal element of a solid sample, which is characterized by

The invention of claim 3 of the present application comprises an electrode for heating the stored solid sample, a furnace for supplying the carrier gas to convert the solid sample into a sample aerosol, and an inductive coupling provided in communication with this furnace. An inductively coupled plasma unit that includes a plasma torch and ionizes the sample aerosol.
A mass analysis unit that receives sample ions ionized by the inductively coupled plasma unit and includes an ion lens unit, a mass filter unit, and an electron multiplier detector, and a sample ion from the inductively coupled plasma unit to the mass analysis unit. It is a gist of an inductively coupled plasma mass spectroscope characterized in that it has a sampling orifice and an interface section having a skimmer orifice.

According to a fourth aspect of the present invention, an oven for heating the stored solid sample is provided with an electrode for converting the solid sample into a sample aerosol, and further, a furnace for forming a metal atomic layer and an output wavelength for the metal atomic layer are provided. It is a gist of an atomic absorption spectroscope characterized in that it is equipped with a light source that generates adjusted light and a light intensity detector that detects the intensity of light that has passed through the atomic vapor layer.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an analyzer for analyzing a metal element of a solid sample according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram of an analyzer for analyzing a metal element of a solid sample according to the present invention.

As shown in FIG. 1, an analyzer for analyzing a metal element of a solid sample according to the present invention, for example, an inductively coupled plasma mass spectrometer (ICP-MS device) 1, heats a stored solid sample S. A furnace 3 equipped with an electrode 2 for supplying a carrier gas and converting the solid sample S into a sample aerosol.
An inductively coupled plasma torch 4 provided in communication with the furnace 3, and an inductively coupled plasma part 5 for ionizing the sample aerosol into the sample; and the inductively coupled plasma part (IC
(P part) 5 receives the sample ions ionized by the sample,
A mass spectrometric section (MS section) 9 including an ion lens section 6, a mass filter section 7, and an electron multiplier detector 8, and sample ions are transferred from the inductively coupled plasma section 5 to the mass spectrometric section 9 for sampling. It has an orifice 10 and an interface portion 12 having a skimmer orifice 11.

The furnace 3 has, for example, a cylindrical body 3a made of carbon and having a length of 30 mm and an inner diameter of 10 mm, and the carbon electrode 2 arranged so as to sandwich the cylindrical body 3a. The stored sample S is heated to generate a sample aerosol, which is a dispersion system in which a dispersion phase is a sample, using argon gas as a carrier gas as a dispersion medium.

The inductively coupled plasma section 5 is for applying a high frequency voltage to the internally coupled inductively coupled plasma torch 4 to ionize the sample aerosol.

The interface section 12 includes a detector 8
A vacuum chamber 14 for separating atmospheric plasma from a high vacuum analyzer section 13 including a rotary vacuum pump 15 for maintaining a predetermined pressure in the interface section 12, and further to the outside of the sampling orifice 10 and the skimmer orifice 11, Sampling cone 16,
It is equipped with a skimmer cone 17. Therefore, the ions are transmitted from the plasma by the sampling cone 16 through the sampling orifice 10 to the interface section 1
2, and the ions are further transferred from the interface section 12 by the skimmer cone 17 to the analyzer section 13 via the skimmer orifice 11.

The mass spectrometric section 9 comprises the ion lens section 6, the mass filter section 7 and the detector section 8.
The ion lens unit 6 comprises a vacuum chamber 18 containing a series of electrostatic ion lenses attached to the rear side of the skimmer cone 17, and the ion lens unit 6 enters the vacuum chamber 18 via a skimmer cone orifice 11. The ion beam is focused on the mass filter unit 7 provided in the analyzer unit. The mass filter unit 7 comprises a quadrupole mass filter essentially consisting of four parallel rods, to which high frequency and DC voltage are applied. For any combination of applied rf voltage and dc voltage, the mass filter only allows ions of a particular mass / charge ratio to pass to the detector 8. As a result, the detector 8
It is possible to separate and analyze ions of different elements. The ion signal of each mass is amplified and then analyzed using a multichannel counter. The mass (element) signal strength is directly proportional to the concentration of that element in the sample.

Next, a method for analyzing a metal element of a solid sample using the inductively coupled plasma mass spectrometer according to the present invention will be described.

Using an inductively coupled plasma mass spectrometer 1 as shown in FIG. 1, a solid sample S cut out from a semiconductor manufacturing member such as VAD or synthetic quartz glass is placed in a furnace 3 and argon is used as a carrier gas. While supplying gas, the electrode 2 is energized to heat the sample S. The metallic element released from the heated sample S becomes particles and becomes a dispersed phase, and forms a sample aerosol (fume) using argon gas as a dispersion medium.

Further, the sample aerosol is introduced into the inductively coupled plasma section 5, and the sample aerosol is ionized by the inductively coupled plasma torch 4.

The sample ionized sample ion is received by the mass spectrometric section 9, the detector 8 measures the ion, and the concentration of the metal element contained in the sample is analyzed. Each isotope appears at a different mass position with a peak intensity that is directly proportional to the initial concentration of that isotope in the sample.
The Cu concentration in the sample is analyzed as shown in FIG.

Further, another embodiment of the solid sample metal element analyzing apparatus according to the present invention will be described.

The present embodiment is a flameless atomic absorption spectrometer, whereas the analyzer of the above embodiment is an inductively coupled plasma mass spectrometer.

For example, as shown in FIG. 2, a metal element analyzer for a solid sample according to the present invention, for example, a flameless atomic absorption spectrometer 21 is provided with an electrode 22 for heating a contained solid sample S, A carrier gas is supplied and the metal element released from the solid sample S is converted into a sample aerosol,
Further, a furnace 23 for atomizing a metal element, an irradiation chamber 24 for retaining atomic vapor from the furnace 23 for irradiation, and
A light source 25 that emits light for irradiating the atomic vapor layer in the irradiation chamber 24 with light of a specific wavelength and a light intensity detector 26 that detects the intensity of light that has passed through the atomic vapor layer are provided.

Next, a method for analyzing a metal element of a solid sample using a flameless atomic absorption spectrometer according to another embodiment will be described.

Using a flameless atomic absorption spectrometer 21 as shown in FIG. 2, a solid sample S cut out from quartz glass for a furnace core tube made of quartz glass is housed in a furnace 23, and argon gas is supplied as a carrier gas. Meanwhile, the electrode 22 is energized to heat the sample S. The heated sample S becomes particles and becomes a dispersed phase, and forms a sample aerosol using argon gas as a dispersion medium. Furthermore, for example, 2000-2
Irradiation chamber 24 by heating to 800 ° C to atomize the metal element
The atomic vapor layer guided to the above is irradiated with light of a specific wavelength emitted from the light source 25, and is analyzed by a light intensity detector 26 that detects the intensity of the light passing through the atomic vapor layer to obtain the atomic vapor amount, Quantify.

To atomize the metal element from the solid sample as described above, the sample S is stored as a solid in the furnace 3, heated by the electrode 2, and the carrier gas is sent to remove the metal element released from the sample S. Since the sample aerosol is formed into particles and further heated to a high temperature, the sample aerosolization and atomization can be easily performed, and the apparatus is also simplified. In the conventional method in which a sample is contained in a container, dissolved in a solution, and introduced into a furnace, the release amount cannot be measured even if the bulk concentration is known.

[0031]

EXAMPLES (Test 1) The amount of Cu released from quartz glass forcibly contaminated with Cu was analyzed under the following test conditions using a furnace used in the detection apparatus according to the present invention as shown in FIG. .

Sample: Quartz glass (length 10 mm x width 3 mm
X thickness 1 mm) was forcibly contaminated with Cu.

(Bulk Cu: 65 ppm) Detector: ICP mass spectrometer (apparatus shown in FIG. 1) Carrier gas: Argon 0.9 L / min Temperature raising conditions: Room temperature → 100 ° C. for 10 seconds as follows:
Also, 100 ° C, 500 ° C, 800 ° C, 1000 ° C, 1
The holding time at 100 ° C. and 1200 ° C. was set to 10 seconds in each case.

(Test 2) The amount of Cu released from the quartz glass in which Cu was forcibly contaminated was analyzed by changing some test conditions of the above Test 1.

Modification: 12 without holding at 800 ° C.
Hold at 00 ° C. for 15 seconds.

(Test 3) The test conditions are the same as those in Test 2 above using clean quartz glass.

Results: The results of Test 1 are shown in FIG. 3, the results of Test 2 are shown in FIG. 4, and the results of Test 3 are shown in FIG. As can be seen in FIGS. 3-5, 12 from the forcedly contaminated quartz sample.
It was directly observed that Cu was rapidly released near 00 ° C. Also, an increase in the amount of release was observed by increasing the time of 1200 ° C., and the temperature dependence of the release was confirmed.
Conventionally, in order to obtain this fact, the impurity distribution analysis before and after the heat treatment of the sample, the diffusion rate calculation, and the relationship with the temperature were estimated by calculation. Therefore, it takes time and there is a problem in accuracy. Since this method is a direct analysis, it was found that it is possible to analyze the release amount quickly and with high accuracy.

[0038]

According to the method for analyzing a metal element of a solid sample and the analyzer for the same according to the present invention, it is possible to analyze the metal element directly from the solid sample, and the structure of the analyzer is simple. And its analyzer.

That is, in the method for analyzing a metal element of a solid sample, a solid sample is heated in a furnace, and a metal component released from the solid sample is introduced together with a carrier gas into an inductively coupled plasma mass spectrometer to analyze a metal element. Therefore, the sample aerosolization is carried out by accommodating the sample as it is in a solid state in a furnace, heating it with an electrode, and sending a carrier gas to atomize the metal element released from the sample.
The sample is placed in a container, dissolved in the solution, and pumped
Unlike supplying to a nebulizer to form a sample aerosol, sample aerosolization is possible easily, and
The device is also simplified.

Since the solid sample is heated in the furnace and the metal element released from the solid sample is introduced into the flameless atomic absorption spectrometer to analyze the metal element, the metal element analysis method for the solid sample is Is stored in a furnace as a solid, heated by an electrode, a carrier gas is sent to atomize the metal element released from the sample to form a sample aerosol, and further atomized by heating, as in the conventional case,
The sample is placed in a container, dissolved in the solution, and pumped
Unlike supplying to a nebulizer and vaporizing a solvent to form a sample aerosol, sample aerosolization and atomization can be easily performed, and the apparatus is also simplified.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an embodiment of a detection device for detecting a metal element of a solid sample according to the present invention.

FIG. 2 is a conceptual diagram of another embodiment of a detection device for detecting a metal element of a solid sample according to the present invention.

FIG. 3 is a test result diagram by a method of detecting a metal element of a solid sample according to the present invention.

FIG. 4 is a test result diagram by a method for detecting a metal element of a solid sample according to the present invention.

FIG. 5 is a test result diagram by a method of detecting a metal element of a solid sample according to the present invention.

FIG. 6 is a conceptual diagram of an embodiment of a detection device for detecting a metal element of a solid sample according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Inductively coupled plasma mass spectrometer (ICP-MS device) 2 Electrode 3 Furnace 3a Cylindrical body 4 Inductively coupled plasma torch 5 Inductively coupled plasma section 6 Ion lens section 7 Mass filter section 8 Electron multiplier tube detector 9 Mass spectrometer Part 10 Sampling orifice 11 Skimmer orifice 12 Interface part 13 High vacuum analyzer part 14 Vacuum chamber 15 Rotary vacuum pump 16 Sampling cone 17 Skimmer cone 21 Flameless atomic absorption spectrometer 22 Electrode 23 Furnace 24 Irradiation chamber 25 Light source 26 Light intensity detector S Solid sample

Claims (4)

[Claims] 1. A solid sample characterized by heating a solid sample in a furnace and introducing a metal component released from the solid sample together with a carrier gas into an inductively coupled plasma mass spectrometer to analyze a metal element. Metal element analysis method. 2. A solid sample is heated in a furnace, and metal atoms released from the solid sample are introduced into a flameless atomic absorption spectroscope to analyze metallic elements in the existing state. Metal element analysis method for solid samples. 3. A furnace comprising an electrode for heating a stored solid sample, a furnace for supplying a carrier gas to convert the solid sample into a sample aerosol, and an inductively coupled plasma torch provided in communication with the furnace, An inductively coupled plasma part for ionizing the sample aerosol, and a mass spectrometric part for receiving the sample ions ionized by the inductively coupled plasma part and comprising an ion lens part, a mass filter part and an electron multiplier detector. An inductively coupled plasma mass spectrometer, comprising: a sample orifice for transferring sample ions from the inductively coupled plasma portion to the mass spectrometer portion; and an interface portion having a skimmer orifice. 4. A furnace comprising an electrode for heating a housed solid sample and converting the solid sample into a sample aerosol, and further, a furnace for forming a metal atomic layer, and a light having an output wavelength adjusted in the metal atomic layer. An atomic absorption spectroscope comprising a light source and a light intensity detector for detecting the intensity of light passing through the atomic vapor layer.