JP4788924B2 - Atomic hydrogen adsorption removal method and apparatus - Google Patents

Description

  The present invention relates to an atomic hydrogen adsorption removal method and an apparatus therefor.

  In recent years, substrate surface cleaning technology using atomic hydrogen has attracted attention mainly in the semiconductor industry. It has also been clarified that atomic hydrogen generated from the raw material determines the performance of the semiconductor device during the thin film deposition process. Therefore, a technique for quantifying the amount of atomic hydrogen generated and a technique for removing atomic hydrogen for controlling the amount of atomic hydrogen are required.

There is a method for measuring the amount of atomic hydrogen by irradiating a special glass with atomic hydrogen and coloring the glass as a simple method known for a long time for quantifying atomic hydrogen. (For example, refer nonpatent literature 1.). However, with this method, it is difficult to accurately measure the amount of atomic hydrogen.
On the other hand, there are a two-photon laser induced fluorescence method and a vacuum ultraviolet absorption method as a method for correctly measuring the amount of atomic hydrogen (see, for example, Non-Patent Document 2). However, both of these methods require a large laser device, which causes problems such as a complicated device configuration and increased device cost.
There is also a quantification method using an extraction reaction of atomic deuterium (D) on crystalline silicon by atomic hydrogen. This method is characterized in that the amount of atomic hydrogen can be measured relatively accurately because it can be distinguished from hydrogen present in the background by using atomic deuterium. (For example, refer nonpatent literature 3 and nonpatent literature 4.). However, in this case, it is difficult to handle such as crystalline silicon must be cleaned in an ultra-high vacuum. In addition, the quantitative reproducibility is very poor and it is used only for some scientific research purposes.
Takashi Morimoto, Koji Yoneyama, Hironobu Umemoto, Satoshi Masuda, Hideki Matsumura, Keiji Ishibashi, Hiroki Sasayama, Hiroshi Kawade, Quantitative determination of H atom density using tungsten oxide-containing glass, Spring 51st Joint Conference on Applied Physics, ( Tokyo), 28P-ZE-1, March 2004 H. Umemoto, K. Ohara, D. Morita, Y. Nozaki, A. Masuda, and H. Matsumura, DirectDetection of Atomic Hydrogen in the Catalytic Chemical Vapor Deposition of the SiH4 / H2 System, J. Appl. Phys., 91, 3, 1650, 2002. HNWaltenburug, JT Yates, Surface-chemistry of silicon, Chem. Reviews, 95, 5,1589 (1995). S. Shimokawa, A. Namiki, T. Ando, Y. Sato, J. Lee, J. Chem. Phys., 112, 356 (2000).

  The problem to be solved is that there is no method for removing atomic hydrogen.

  This invention is made | formed in view of said subject, and it aims at providing the atomic hydrogen adsorption removal method and apparatus which can remove atomic hydrogen.

The method for adsorbing and removing atomic hydrogen according to the present invention includes a desorption step of desorbing atomic hydrogen adsorbed on Inconel by heating Inconel (registered trademark) , and exposing Inconel to a target gas containing atomic hydrogen. And an adsorption removal step of adsorbing and removing atomic hydrogen in the target gas.

  Further, the atomic hydrogen adsorption / removal device according to the present invention includes an adsorption removal unit comprising an inconel and a heating mechanism for heating the inconel, and the inconel in a state where the atomic hydrogen is desorbed in the target gas containing atomic hydrogen. It is characterized by being used after being exposed to.

  In the present invention, the atomic hydrogen in the target gas can be removed using a material capable of remarkably adsorbing and desorbing atomic hydrogen.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

First, the atomic hydrogen determination method according to the present invention will be described.
In the atomic hydrogen quantification method according to the present invention, after preparing a sensor material under initial conditions (sensor preparation step), the sensor is exposed to a measurement target gas containing atomic hydrogen, in other words, the sensor is irradiated with atomic hydrogen. (Sensor exposure process), and further heating the sensor (heating process) desorbs the hydrogen produced on the sensor. Next, the strength of the desorbed hydrogen is measured by mass spectrometry (strength measurement step), and the irradiation time of atomic hydrogen on the sensor material determined in advance and the strength of the hydrogen desorbed from the sensor material by mass spectrometry are measured. Based on the correlation, the atomic hydrogen in the measurement target gas is quantified (atomic hydrogen quantification step).
Here, as a method of preparing the sensor material under the initial conditions, a method of performing initial cleaning by removing hydrogen at a high temperature can be used. However, the method is not limited to this as long as reproducibility can be ensured.

In the atomic hydrogen quantification method according to the present invention, more preferably, in the sensor preparation step, atomic deuterium (D) is irradiated (captured) by irradiating the sensor material with atomic deuterium (D). ) Deuterium termination. Accordingly, in the sensor exposure step, by irradiating the atomic hydrogen on the sensor, abstraction reaction of deuterium by atomic hydrogen _(D) (D 2) and deuterium compounds (HD) occurs. Next, after heating the sensor (heating step), in the strength measurement step, the deuterium compound (HD) and deuterium (D ₂ ) strengths desorbed from the sensor are measured, and the atomic weight remaining in the sensor is thereby measured. The amount of hydrogen (D) is calculated. Next, in the atomic hydrogen determination step, the correlation between the intensity of the atomic hydrogen (H) irradiation with respect to the sensor determined in advance and the amount of atomic deuterium (D) remaining on the sensor by mass spectrometry (deuterium The atomic hydrogen (D) in the measurement target gas is quantified based on the calibration curve) based on the amount of molecules contained. In the above method of irradiating atomic deuterium, the sensor is exposed to atomic hydrogen during the sensor exposure process. The gas containing the desorbed component desorbed from the mass is subjected to mass spectrometry to measure the strength of deuterium or deuterium compound (strength measurement step A). In addition, a method of measuring the strength of deuterium or a deuterium compound by mass spectrometry of a gas containing a desorbed component that is directly desorbed from the sensor by an extraction reaction may be used (strength measurement step B).
In the case of the quantitative method using the atomic hydrogen extraction with atomic hydrogen described in the prior art, it is difficult to handle because the crystalline silicon must be cleaned in an ultra-high vacuum. . Also, quantitative reproducibility is very poor. On the other hand, according to the present invention, since a large amount of extracted gas can be obtained by using a sensor irradiated with a large amount of atomic deuterium, there is no need for complicated handling such as applying a high degree of cleaning to the sample. Atomic hydrogen can be quantified with high accuracy. In addition, according to this method, quantitative determination of atomic deuterium can also be performed.

When the atomic deuterium is not irradiated, the operations described above are performed, for example, in the sensor preparation step under an ultrahigh vacuum condition of about 10 ⁻⁸ Pa or less and a temperature condition of about 50 ° C. or less. The sensor exposure step is performed under an ultrahigh vacuum condition of about 10 ⁻⁸ Pa or less and a temperature condition of about 20 to 500 ° C. In the intensity measurement step, the measurement is performed under an ultrahigh vacuum condition of about 10 ⁻⁸ Pa or less. In the strength measurement step B, the measurement is performed under an ultrahigh vacuum condition of about 10 ⁻⁸ Pa or less and a temperature condition of about 20 to 500 ° C.
On the other hand, when irradiating atomic deuterium, for example, in the sensor preparation step, under an ultrahigh vacuum condition of about 10 ⁻⁴ Pa to 10 ⁻⁸ Pa and under a temperature condition of room temperature to about 100 ° C. Do. The sensor exposure step is performed under an ultrahigh vacuum condition of about 1 Pa to 10 ⁻⁸ Pa and a temperature condition of about −269 to 100 ° C. In the strength measurement step A, the measurement is performed under an ultrahigh vacuum condition of about 10 ⁻⁴ Pa to 10 ⁻⁸ Pa and under a temperature condition of about 100 to 500 ° C. In the strength measurement process B, the measurement is performed under an ultrahigh vacuum condition of about 10 ⁻⁴ Pa to 10 ⁻⁸ Pa and a temperature condition of about room temperature to about 100 ° C.

  In the present invention, as long as the sensor material satisfies the determination of atomic hydrogen, the sensor material takes in a sufficient amount of atomic deuterium and irradiates with atomic hydrogen, particularly when irradiating atomic deuterium. There are no particular limitations on the type of material as long as a sufficient amount of extraction gas is generated, and appropriate materials such as crystalline silicon, stainless steel, and aluminum can be used. However, from the viewpoint of more effectively expressing the above action, it is selected from Ni, Cr, Al, Mn, Fe, Co, Be, W, V, Si, C, Nb, Ta, Cu, and Ti. It is more preferable to use an alloy composed of at least two kinds of metals. As such an alloy, it is more preferable to use Inconel, and Invar, Hastelloy and the like are also preferable.

  In the present invention, mass spectrometry can be performed using an appropriate apparatus, but a quadrupole mass spectrometer is more preferable.

  An atomic hydrogen quantification apparatus according to the present invention that can suitably implement the atomic hydrogen quantification method according to the present invention will be described with reference to FIG.

In the atomic hydrogen quantification apparatus (atomic hydrogen monitoring apparatus) 10 shown in FIG. 1, a sensor substrate (sensor) 14 and a heating mechanism 16 for heating the sensor substrate 14 are provided (accommodated) in the sensor chamber 12. The heating mechanism 16 includes, for example, a heating plate that also serves as a mounting table for the sensor substrate 14 and a heat source that heats the heating plate.
Connected to the sensor chamber 12, an atomic deuterium introduction unit 18, a measurement target gas introduction unit 20, and a sensor chamber gas lead-out unit 22 are provided. The measurement target gas introduction unit 20 includes a valve mechanism such as a gate valve that connects the sensor chamber 12 and the outside so as to be able to shut off the flow. Each of the atomic deuterium introduction section 18 and the sensor chamber gas outlet section 22 is also provided with an appropriate shut-off mechanism. If atomic deuterium is not used, the atomic deuterium introduction part 18 is not necessary.
The apparatus configured as described above can be used, for example, as a portable type, transported to a measurement place, and connected to an atomic deuterium generator, a measurement target gas, and a mass spectrometer, respectively.

The apparatus configured as described above can also be used as a portable atomic hydrogen removing apparatus (portable atomic hydrogen monitoring apparatus). In this case, the measurement target gas introduction part (target gas introduction part) 20 is connected to an atmosphere containing atomic hydrogen to be removed. Further, the sensor chamber gas deriving unit 22 is unnecessary, and further, if the atomic deuterium is previously taken into the sensor substrate 14, the atomic deuterium introducing unit 18 is also unnecessary.
In this case, it is more convenient to adopt a method in which atomic deuterium is taken in and the heated sensor substrate 14 is arranged in an atmosphere containing the atomic hydrogen to be removed.

  In addition, as shown in FIG. 1, the atomic hydrogen quantification apparatus 10 has an atomic deuterium generator 24 connected to the atomic deuterium introduction section 18 and a mass spectrometer 26 connected to the sensor chamber gas outlet section 22, respectively. It can also be used. When atomic deuterium is not used, the atomic deuterium introduction part 18 and the atomic deuterium generator 24 are not necessary.

A method of using the atomic hydrogen quantification apparatus 10 will be described.
Atomic deuterium generated from the atomic deuterium generator 24 is introduced into the sensor chamber 12 and the sensor substrate 14 is irradiated with atomic hydrogen. In a state where the sensor substrate 14 is heated by the heating mechanism 16, a measurement target gas containing atomic deuterium or an atmosphere gas containing atomic hydrogen to be removed is introduced into the sensor chamber 12.
The measurement target gas containing atomic deuterium or the atmospheric gas containing atomic hydrogen to be removed is generated by, for example, a thin film deposition apparatus or a dry etching apparatus.
These so-called atomic hydrogen generator and atomic hydrogen quantification apparatus 10 are connected via a gas introduction unit 20 to be measured, and a gas containing atomic hydrogen of the atomic hydrogen generator is introduced into the sensor chamber 12, The heated sensor substrate 14 is exposed to this gas. Atomic hydrogen is consumed in the reaction with atomic deuterium.

  The sensor substrate 14 irradiated with atomic hydrogen is heated by the heating mechanism 16 to a temperature higher than that at the time of irradiation, and the strength of desorbed deuterium or deuterium compound (HD) is measured by the mass spectrometer 26. From this, the amount of atomic deuterium remaining in the sensor is calculated. And based on the correlation data of the intensity | strength by mass spectrometry of the atomic hydrogen irradiation amount with respect to the sensor board | substrate 14 previously calculated | required incorporated in the mass spectrometer 26, and the amount of atomic deuterium which remains in the sensor board | substrate 14 Atomic hydrogen is quantified.

  The result of the deuterium extraction experiment using atomic hydrogen will be described below.

Fig. 2-1 shows an extraction reaction by atomic hydrogen (H) for a sensor that uses an alloy (Inconel) composed of Ni, Cr, Al, Mn, Fe, and Co and adsorbs atomic deuterium (D). The experimental results are shown. In addition, the results of using stainless steel, crystalline silicon, and aluminum as sensors instead of this alloy are also shown in FIGS. FIGS. 2-1 to 5-1 show the relationship between the irradiation time of atomic hydrogen and the deuterium (D ₂ ) intensity desorbed, respectively. FIGS. 2-2 to 5-2 show the relationship between the irradiation time of atomic hydrogen and the desorption HD intensity.
Each material (sensor) used in this experiment was only organically cleaned. From this result, it can be seen that each material takes in a lot of atomic hydrogen and causes a reaction with atomic deuterium.
It can also be seen that Inconel has a stronger initial deuterium strength than other materials and takes in a lot of atomic hydrogen to cause a reaction with atomic deuterium. It can also be seen that Inconel has a sharp decrease in deuterium intensity with respect to atomic hydrogen irradiation time compared to other materials. This shows that the amount of atomic hydrogen can be obtained more correctly by using Inconel. The results also show that Inconel plays the most efficient role in removing atomic hydrogen.

FIG. 6 shows the relationship of deuterium intensity when the deuterium is sufficiently irradiated with deuterium atoms (atomic deuterium) and then desorbed by temperature with respect to Inconel whose irradiation time of atomic deuterium is changed. The pressure at the time of irradiation with atomic deuterium (corresponding to the flux of atomic deuterium) shows two results of 0.5 × 10 ⁻⁵ Pa and 2.5 × 10 ⁻⁵ Pa.
From this result, it is understood that when the pressure is 0.5 × 10 ⁻⁵ Pa, there is a linear relationship between the irradiation time of atomic deuterium and the deuterium intensity within a range of 300 seconds. In addition, when the pressure is 2.5 × 10 ⁻⁵ Pa, there is the same linear relationship as before in the initial irradiation for about 50 seconds, and the deuterium intensity is the same as when the pressure is 0.5 × 10 ⁻⁵ Pa Compared to the increase in pressure, it is 5 times. This result shows that atomic hydrogen can be measured correctly.
The above experiment was repeated. Compared to stainless steel, crystalline silicon, and aluminum, Inconel was able to obtain the same results with good reproducibility.

Next, the method for adsorbing and removing atomic hydrogen according to the present invention will be described.
The method for adsorbing and removing atomic hydrogen according to the present invention includes an adsorption and removing step of adsorbing and removing atomic hydrogen in a target gas by exposing a material capable of adsorbing and desorbing atomic hydrogen to the target gas containing atomic hydrogen. A desorption step of desorbing atomic hydrogen adsorbed on the material.

Here, as the material capable of adsorbing and desorbing atomic hydrogen, the materials described in the explanation of the atomic hydrogen determination method can be used.
That is, the material capable of adsorbing and desorbing atomic hydrogen is not particularly limited as long as it exhibits the effects of the present invention, and for example, an appropriate material such as crystalline silicon, stainless steel, or aluminum is used. Can do. However, from the viewpoint of more effectively expressing the above action, it is selected from Ni, Cr, Al, Mn, Fe, Co, Be, W, V, Si, C, Nb, Ta, Cu, and Ti. It is more preferable to use an alloy composed of at least two kinds of metals, and it is more preferable to use Inconel as such an alloy.

  In the adsorption removal step, for example, the material is exposed to a target gas containing atomic hydrogen. Thereby, the atomic hydrogen in the target gas can be adsorbed and removed.

  In the desorption process, for example, the material is heated to a temperature of 100 to 500 ° C. under atmospheric pressure or reduced pressure. At this time, the sensor irradiated with atomic deuterium described in the explanation of the atomic hydrogen quantification method can be used. By this step, atomic hydrogen adsorbed on the material can be removed, so that the same material can be used repeatedly.

The atomic hydrogen adsorption / removal device according to the present invention, which can suitably realize the atomic hydrogen adsorption / removal method according to the present invention described above, comprises a material capable of adsorbing and desorbing atomic hydrogen and a material that heats the atomic hydrogen. And a heating mechanism that desorbs hydrogen, and the material in a state where atomic hydrogen is desorbed is exposed to a target gas containing atomic hydrogen. In addition, a heating mechanism becomes unnecessary by the method of exchanging and using a material.
As such an apparatus, for example, the apparatus shown in FIG. 1 described in the explanation of the atomic hydrogen quantification apparatus can be used. Alternatively, an apparatus composed only of a material and a heating mechanism may be arranged and used as it is in a target gas containing atomic hydrogen. Alternatively, an apparatus made of only a material may be used as it is in a target gas containing atomic hydrogen.

It is a figure which shows schematic structure of an atomic hydrogen determination apparatus. When irradiating a sensor material with atomic deuterium, it is a figure which shows the relationship between the irradiation time of atomic hydrogen at the time of using Inconel for a sensor, and the intensity | strength of deuterium to detach | desorb. When irradiating a sensor material with atomic deuterium, it is a figure which shows the relationship between the irradiation time of atomic hydrogen and the intensity | strength of desorption when Inconel is used for a sensor. When irradiating a sensor material with atomic deuterium, it is a figure which shows the relationship between the irradiation time of atomic hydrogen when the stainless steel is used for a sensor, and the intensity | strength of deuterium to detach | desorb. In the case where atomic deuterium is irradiated to the sensor material, it is a diagram showing the relationship between the irradiation time of atomic hydrogen and the desorption HD intensity when stainless steel is used for the sensor. FIG. 5 is a diagram showing the relationship between the irradiation time of atomic hydrogen and the deuterium intensity desorbed when crystalline silicon is used for the sensor when atomic deuterium is irradiated to the sensor material. In the case where atomic deuterium is irradiated to a sensor material, it is a diagram showing the relationship between the irradiation time of atomic hydrogen and the desorption HD intensity when crystalline silicon is used for the sensor. When irradiating a sensor material with atomic deuterium, it is a figure which shows the relationship between the irradiation time of atomic hydrogen when aluminum is used for a sensor, and the intensity | strength of deuterium to detach | desorb. FIG. 5 is a diagram showing the relationship between the irradiation time of atomic hydrogen and the desorption HD intensity when aluminum is used for the sensor when atomic deuterium is irradiated to the sensor material. It is a figure which shows the relationship of the deuterium intensity | strength when carrying out thermal desorption with respect to Inconel which changed the irradiation time of atomic deuterium in the case of irradiating a sensor material with atomic deuterium.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Atomic hydrogen determination apparatus 12 Sensor chamber 14 Sensor substrate 16 Heating mechanism 18 Atomic deuterium introduction part 20 Measurement object gas introduction part 22 Sensor chamber gas derivation part 24 Atomic deuterium generator 26 Mass spectrometer

Claims (2)

Desorption process to desorb atomic hydrogen adsorbed on Inconel by heating Inconel (registered trademark) , and adsorption of atomic hydrogen in target gas by exposing Inconel to target gas containing atomic hydrogen An adsorption removal process for removing the atomic hydrogen.   Atomic hydrogen adsorption characterized in that it has an adsorption removal unit consisting of inconel and a heating mechanism that heats inconel, and inconel in a state where atomic hydrogen is desorbed is exposed to the target gas containing atomic hydrogen Removal device.

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