JP2008058154A - X-ray photoelectron spectroscopic instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve precision of analysis on a sample surface by controlling a damage such as a change in a bonding state, and the composition of the sample. <P>SOLUTION: The system comprises: a UV light source 17 emitting light with the wavelength of 184.9 nm; a UV light source 18 emitting light with the wavelength of 253.7 nm; an oxygen supply tube 21 to supply oxygen; an exhaust pipe 22 capable of auxiliary evacuation for generating vacuum by evacuation; an auxiliary evacuation chamber 12 for cleaning a sample surface with application of UV light from UV light sources 17 and 18 under a hydrocarbon-free oxygen atmosphere; a gate valve 23; and a communicating passage 15 which communicates a measuring chamber 11 with the auxiliary evacuation chamber 12 and carries the cleaned sample to the measuring chamber 11 when the gate valve is opened. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an X-ray photoelectron spectrometer equipped with a cleaning mechanism.

  The surface of samples stored in the atmosphere is usually contaminated with natural oxidation or hydrocarbons. These contaminations are the surfaces of samples such as X-ray photoelectron spectroscopy (XPS). This hinders measurement and analysis during analysis.

  When performing surface analysis of a sample, cleaning methods using organic solvents (such as acetone) and ion sputtering methods using various ions (as a cleaning method to remove contaminants present on the sample surface) Sputter cleaning is generally known (see, for example, Non-Patent Document 1).

In particular, the ion sputtering method is a method of irradiating a sample to be measured with an ion beam and removing the atoms of the deposits existing on the sample surface by sputtering, and is widely used. As the ion species used here, a rare gas is used in order to avoid a chemical reaction with the sample, and Ar ions accelerated to several hundred to several keV are generally used. Therefore, some XPS apparatuses are provided with an ion sputtering mechanism using Ar or He.
X-ray photoelectron spectroscopy, edited by Japan Society for Surface Science, p.60, p.73, p.179-181, Maruzen Co., Ltd. (1998)

  However, in the above ion sputtering method, by irradiating the sample with ions, the bonding state and the composition are changed due to decomposition or reduction of the compound in the sample. In addition, it often involves structural changes such as rough surface shapes and cone formation.

  Such a change in bonding state and composition makes the bonding state and composition of the sample different from that before sputtering in the surface analysis (measurement) performed after cleaning, and the change in structure is the depth at the time of depth direction analysis. This causes degradation of the resolution.

  Even if the sample is cleaned and cleaned by ion sputtering in advance, if there is a process in contact with the atmosphere before the measurement, such as moving to a device that performs analysis (measurement), the components in the atmosphere are There is also a problem that the cleaning effect cannot be sufficiently obtained by reattaching to the surface.

  Therefore, when performing surface analysis using XPS or the like, the properties of the sample itself are accurate without affecting the state of the sample, which is the test substance, without reattaching contaminants. Actually, a method that can measure well has not been established yet.

  The present invention has been made in view of the above, and suppresses reattachment of contaminants before cleaning after cleaning and damage of the sample due to cleaning, and can perform measurement and analysis such as surface analysis of the sample with high accuracy. An object of the present invention is to provide a linear photoelectron spectrometer, and to achieve the object.

  According to the present invention, an X-ray photoelectron spectrometer (hereinafter abbreviated as XPS apparatus) is based on the knowledge that cleaning effect in the atmosphere reduces the cleaning effect on the sample surface due to resorption of contaminants in the atmosphere. And an oxygen-containing atmosphere (hereinafter referred to as “UV”) that is preliminarily evacuated and does not contain hydrocarbons or has a small amount (preferably low pressure or vacuum). The cleaning atmosphere is sometimes referred to as “cleaning atmosphere”).

  In order to achieve the above object, the X-ray photoelectron spectrometer according to the present invention irradiates light having a peak wavelength in a region having a wavelength of 120 nm or more and less than 200 nm and light having a peak wavelength in a region having a wavelength of 200 nm or more and 300 nm or less. And an oxygen supply means for supplying oxygen and an exhaust means for exhausting, and after evacuating by the exhaust means or replacing the gas, oxygen is supplied by the oxygen supply means, and in the presence of oxygen formed by the irradiation means Measurement of measuring the preliminary exhaust chamber and the sample by irradiating two light beams having different peak wavelengths to clean at least a part of the sample, a partition valve, and opening the partition valve And a communication means capable of communicating with the chamber and allowing the cleaned sample to be carried into the measurement chamber.

Preliminary exhaust refers to exhausting the indoor air, such as when a sample is introduced into a measurement chamber for measuring the sample or a container connected to the measurement chamber. The preliminary exhaust is preferably performed from the atmospheric pressure to a constant low pressure, for example, a low pressure of 10 ⁻³ Pa or less or a vacuum state.
Further, “having a peak wavelength” means that a waveform protruding in a mountain shape exists in the absorption spectrum of light, and the absorption peak may not necessarily be the maximum.

  In the X-ray photoelectron spectrometer (XPS device) of the present invention, the conventional sputter cleaning or the like causes a change in the binding state and composition due to decomposition or reduction of the sample compound due to ion irradiation or the like, and correct measurement results are obtained. Although not obtained, the sample was cleaned (cleaned) in advance under a UV cleaning atmosphere after evacuation or gas replacement with a gas having low reactivity with oxygen (for example, an inert gas) (specifically, After pre-evacuation to a desired low pressure or vacuum state, or after pre-evacuation or gas replacement without pre-exhaust, oxygen is supplied to the sample to be measured. Irradiation with two different types of short-wavelength light (preferably ultraviolet light) can damage the sample (bonding state, composition change, structural change, etc.) Ku, also, details as described later, to oxidize the contaminants present in the sample surface, since changing the volatile substances to be removed, good clean (cleaning) effect is obtained.

  In addition, the preliminary exhaust chamber constituting the apparatus is provided with a cleaning mechanism, and the preliminary exhaust chamber to be cleaned is configured to be able to communicate with the measurement chamber for measuring the sample without exposing the cleaned sample to the atmosphere. Since it can be carried into the measurement chamber, it is possible to prevent the reattachment of contaminants before the measurement and to accurately measure the properties of the surface of the sample.

Here, the cleaning action by irradiating two types of short wavelength light having different wavelengths will be described in detail below. That is,
When the sample surface is first irradiated with light on the short wave side (120 nm ≦ wavelength λ <200 nm), the molecules of contaminants (contaminants) existing on the sample surface are cut, and at the same time, oxygen molecules (O ₂ ) Decomposes. The decomposition generates active single-molecule oxygen O (ground state oxygen having low energy), and when this active single molecule O is combined with oxygen molecule O ₂ , ozone O ₃ is generated. The generated ozone O ₃ absorbs the irradiated long-wave side light (200 nm ≦ wavelength λ ≦ 300 nm) and is decomposed again into O ₂ and O to generate active oxygen O. The active oxygen O is in a high energy excited state, and when the active oxygen is combined with molecules of the deposit on the sample surface, the deposit is oxidized to a volatile product and then removed.

At this time, the inside of the preliminary exhaust chamber in which the sample is placed does not necessarily need to form a low pressure or a vacuum state by the preliminary exhaust, but the pressure is preferably 10 ⁻³ Pa or less.
Since the sample is generally introduced into a measurement chamber where a high vacuum state is formed, the preliminary exhaust chamber is set to a low pressure or a vacuum state after cleaning.

  In the present invention, the sample is provided in the measurement chamber (XPS device) while suppressing the reattachment of the contaminants to the sample surface after removing the deposits (contaminants) by exhausting or replacing the preliminary exhaust chamber. Can be carried into the measurement chamber), and the clean state during measurement of the sample surface can be effectively enhanced.

  The X-ray photoelectron spectrometer according to the present invention has been kept useful as a cleaning method such as ion irradiation because it has a small effect on the sample during cleaning such as damage (bonding state, composition change, structural change, etc.). It is possible to construct a measurement system applicable to the measurement of samples in a wide range of fields such as organic materials such as polymers, semiconductor materials, and metal materials such as electrodes, which are not suitable because they are easily damaged by the cleaning method.

  According to the present invention, there is provided an X-ray photoelectron spectrometer capable of accurately performing measurement and analysis such as surface analysis of a sample by suppressing reattachment of a contaminant before cleaning and cleaning of the sample due to cleaning. be able to.

  Hereinafter, an example of an embodiment of an X-ray photoelectron spectrometer (XPS apparatus) of the present invention will be described in detail with reference to FIGS. However, the present invention is not limited to these embodiments.

  In the present embodiment, the case where two types of UV light sources having different peak wavelength regions are used as irradiation means will be mainly described.

  As shown in FIG. 1, the XPS apparatus of this embodiment includes a measurement chamber 11 that is a measurement chamber for sample measurement, an oxygen supply pipe that supplies oxygen, and an exhaust mechanism that exhausts the chamber, and cleans the sample. The preliminary exhaust chamber 12, UV light sources 17 and 18 that are irradiation means attached to the preliminary exhaust chamber 12, and a partition valve are provided, and a communication state between the measurement chamber 11 and the preliminary exhaust chamber 12 is formed by switching the partition valve. And a communication passage 15 which is a communication means that can be used.

  The XPS device irradiates the surface of a solid sample with X-rays (for example, soft X-rays such as Mgkα rays and Alkα rays), and measures the energy inherent to the element of photoelectrons emitted from the surface several nanometer region. Analysis of constituent elements and chemical bonding states on the material surface is performed, and sample measurement is performed by the measurement chamber 11.

The measurement chamber 11 has an X-ray generator, is a measurement chamber for applying X-rays to a target sample and performing measurement by X-ray photoelectron spectroscopy, and is in a predetermined low-pressure state (preferably 10 ⁻⁶ to The sample surface is configured so that X-ray irradiation can be performed while maintaining a vacuum state of 10 ⁻⁸ Pa. This measurement chamber can be configured in the same manner as a commercially available XPS apparatus (for example, PHI-5500MC manufactured by ULVAC-PHI).
The measurement conditions at the time of measurement can be selected in the same manner as in the past depending on the type and purpose of the sample.

  When measuring a sample in a measurement chamber, the photoelectrons emitted by X-ray irradiation are scattered by gas molecules in the measurement chamber or the sample surface is oxidized by oxygen molecules present in the measurement chamber. In this embodiment, since the measurement of the photoelectron spectrum reflecting the electronic state in the inside becomes difficult, in this embodiment, the communication chamber is connected to the measurement chamber 11 so as to communicate with the measurement chamber 11 so that the inside of the measurement chamber is not exposed to the atmosphere. A preliminary exhaust chamber 12 is provided through 15.

  The preliminary exhaust chamber 12 is a sample exchange chamber in which an exhaust mechanism is constructed so that a measurement sample can be taken in and out and the sample can be exchanged. After the sample is stored, the chamber is exhausted (preliminary exhaust) by the exhaust mechanism. , Low pressure or vacuum can be formed.

The exhaust mechanism is configured by connecting an exhaust pipe 22 at one end to the exhaust port of the preliminary exhaust chamber. The exhaust mechanism is sucked and exhausted by a suction pump (not shown) attached to the exhaust pipe 22, and the preliminary exhaust chamber is exhausted. The pressure can be low or vacuum (preferably vacuum).
The suction pump can be selected from known suction devices such as a rotary pump and a turbo molecular pump.

Here, the preliminary exhaust is exhausting the indoor atmosphere, and can be exhausted so that at least hydrocarbons are exhausted, preferably exhausted below atmospheric pressure substantially free of hydrocarbons, especially The exhaust is preferably performed from atmospheric pressure to a constant low pressure (preferably 10 ⁻³ Pa or less). “Substantially free” means that the measurement accuracy of the sample after cleaning is not impaired.

  In the present embodiment, in order to perform cleaning, which will be described later, after the sample is stored in the preliminary exhaust chamber in the atmosphere, or in order to move the cleaned sample to the measurement chamber after cleaning, preliminary exhaust is performed to obtain a desired low pressure. Or form a vacuum. At this time, the atmosphere is discharged in the former and oxygen gas is mainly discharged in the latter.

The low pressure or vacuum state refers to a state where the pressure in the preliminary exhaust chamber is 10 ⁻³ Pa or less, preferably a vacuum state in the range of 10 ⁻⁶ to 10 ⁻⁸ Pa.

The preliminary exhaust chamber is further connected to one end of an oxygen supply pipe 21 for supplying an oxygen-containing gas into the room, and the oxygen-containing gas is supplied to the preliminary exhaust chamber to adjust the atmosphere to an atmosphere in which oxygen exists. can do. The other end of the oxygen supply pipe 21 is connected to an oxygen supply device or an oxygen tank (not shown).
The oxygen-containing gas is a gas that does not substantially contain hydrocarbons, and “substantially does not contain” means a range that does not impair the measurement accuracy of the sample after cleaning as described above.

  Further, flanges (windows) 13 and 14 for introducing ultraviolet light are formed in the preliminary exhaust chamber 12, and a UV light source 17 and a UV light source 18 are attached to the flanges, respectively. The accommodated sample can be irradiated with ultraviolet rays (UV) simultaneously or alternately.

In the present embodiment, the UV light source 17 can irradiate the sample with ultraviolet light having a peak wavelength of 184.9 nm, and the UV light source 18 can irradiate the sample with ultraviolet light having a peak wavelength of 253.7 nm. Irradiation with ultraviolet light is preferably performed simultaneously from both the UV light source 17 and the UV light source 18, but irradiation with the UV light source 18 may be performed slightly after irradiation with the UV light source 17.
By irradiating two types of ultraviolet rays having different peak wavelengths in a UV cleaning atmosphere, the sample surface can be cleaned well.

A controller is electrically connected to each of the UV light sources 17 and 18 so that irradiation for a predetermined time can be performed with desired irradiation energy.
Moreover, although irradiation time changes with the kind of sample, irradiation energy, etc., about 10 to 300 second is suitable.

The irradiation energy of the UV light source is preferably 0.5 kw / m ² or more and more preferably in the range of 3 to 4 kw / m ² in terms of the cleaning effect.

  As the UV light source, in addition to a light source that emits ultraviolet light having a peak wavelength at 184.9 nm or 253.7 nm as in the present embodiment, a peak wavelength in a range from 120 nm to less than 200 nm from various commercially available light sources. A light source that emits light having a peak wavelength and a light source that emits light having a peak wavelength in a wavelength region of 200 nm to 300 nm can be appropriately selected and used.

  As in the present embodiment, the irradiation means used for cleaning the sample has a light source (first light source) that emits light having a peak wavelength in a region having a wavelength of 120 nm or more and less than 200 nm, and a peak wavelength in a region having a wavelength of 200 nm or more and 300 nm or less. A light source (second light source) that emits light having two types of UV light sources, light having a peak wavelength in a region of wavelength 120 nm or more and less than 200 nm, and light having a peak wavelength in a region of wavelength 200 nm or more and 300 nm or less It is also possible to use a single light source that can irradiate both.

  The preliminary exhaust chamber 12 is further provided with an inlet for introducing a sample, and a sample introduction mechanism 16 for introducing a measurement sample into the preliminary exhaust chamber 12 through the sample inlet. Is provided. The sample introduction mechanism 16 can introduce a sample to be measured into the preliminary exhaust chamber.

  The preliminary exhaust chamber 12 has a function of forming a low pressure or a vacuum state by preliminary exhaust when the sample is introduced into the measurement chamber 11, and further, before introducing the sample into the measurement chamber 11, UV cleaning is performed in advance as described above. The sample surface is cleaned by irradiating with ultraviolet rays in an atmosphere. Because of ultraviolet irradiation, the sample surface can be cleaned without damaging the sample.

For cleaning the surface of the sample, the sample is stored in the preliminary exhaust chamber 11 in the atmosphere and sealed, oxygen is supplied from the oxygen supply pipe 21, and two types of ultraviolet rays having different wavelengths are emitted from the UV light sources 17 and 18 in the UV cleaning atmosphere. Irradiate the sample.
At this time, the oxygen concentration in the atmosphere is preferably 25% or more.

Specifically, the sample surface is first irradiated with light of 184.9 nm from the UV light source 17 in a UV cleaning atmosphere, and the adhered molecules that are contaminants existing on the sample surface are cut. At the same time, oxygen molecules (O ₂ ) in the atmosphere are decomposed. At this time, active monomolecular oxygen O (low-energy ground state oxygen) is generated by decomposition, and the active monomolecule O combines with oxygen molecules O ₂ to generate ozone O ₃ . The generated ozone O ₃ absorbs light of 253.7 nm irradiated by the UV light source 18 and is decomposed again into O ₂ and O to generate active oxygen O. Since the active oxygen O generated at this time is in an excited state with high energy, when the active oxygen is combined with the molecules of the deposit on the sample surface, the deposit is oxidized and changed into a volatile product. In this way, deposits are removed and the sample surface can be cleaned.

Here, regarding the cleaning effect by ultraviolet light in the present invention, MoO ₃ is cleaned by irradiating two kinds of ultraviolet light having different wavelengths having a peak wavelength at 184.9 nm or 253.7 nm in a UV cleaning atmosphere. 2 and a case where cleaning is performed by ion sputtering using conventional Ar ions will be described with reference to the spectrum of FIG.
As shown in FIG. 2- (a), in the case of the present invention in which two types of ultraviolet light having different wavelengths are irradiated in a UV cleaning atmosphere, almost no change in spectrum from the initial stage is observed, and the sample is in a bonded state or composition. It can be seen that there is no damage accompanying the change of On the other hand, in the case of ion sputtering, as shown in FIG. 2- (b), the spectrum change from the beginning increases with time, and the time increases, so that the number of oxygen gradually decreases. It can be seen that there is a change (damage). Thus, the cleaning according to the present invention is effective in that the sample itself can be measured and analyzed.

  The communication passage 15 has one end connected to the measurement chamber 11 and the other end connected to the preliminary exhaust chamber 12, and a gate valve 23 is attached near the center of the passage as shown in FIG. By opening and closing the gate valve 23, the measurement chamber 11 and the preliminary exhaust chamber 12 are separated and sealed when they are closed, and when the valve is opened, the measurement chamber 11 and the preliminary exhaust chamber 12 are communicated with each other by the communication passage 15. can do.

  As described above, the preliminary exhaust chamber 12 is adjusted to a low pressure or a low vacuum state by the preliminary exhaust after cleaning. However, the cleaning is performed by opening the gate valve 23 to allow the measurement chamber 11 and the preliminary exhaust chamber 12 to communicate with each other. The finished sample can be moved to the measurement chamber without touching the atmosphere.

  As described above, when the sample is stored in the preliminary exhaust chamber 12, the gate valve 23 is closed in advance to prevent the air from entering the measurement chamber 11 and the sample is removed by the cleaning mechanism provided in the preliminary exhaust chamber 12. When the surface is cleaned, the preliminary exhaust chamber 12 keeps the state at the end of cleaning, opens the gate valve 23, and sends the sample to the measurement chamber 11 through the communication passage 15, so that the surface of the cleaned sample is cleaned. It is possible to prevent the measurement accuracy from being lost due to re-adhesion of pollutants in the atmosphere or the like.

When the measurement is performed by the XPS apparatus of the present embodiment, first, the target sample is introduced into the preliminary exhaust chamber 12 in the atmosphere using the sample introduction mechanism 16, and the indoor air is preliminarily exhausted from the exhaust pipe 22 after the introduction. A low pressure or vacuum state (preferably a pressure state of 10 ⁻³ Pa or less) is formed. Thereafter, oxygen is supplied into the preliminary exhaust chamber through the oxygen supply pipe 21, and the sample surface is cleaned (cleaned) by irradiating the sample with UV light from the UV light sources 17 and 18 in a UV cleaning atmosphere. After the cleaning is completed, oxygen in the room is exhausted from the exhaust pipe 22 again to form a desired low pressure or vacuum state (preferably a pressure state of 10 ⁻³ Pa or less). Then, the gate valve 23 is opened and the measurement chamber 11 is in a low-pressure state (preferably in a vacuum state) in advance, or the exhaust pipe 22 is continuously evacuated to the communication passage 15 and the measurement chamber 11 in a low-pressure state (preferably vacuum). The preliminary exhaust chamber 12 and the measurement chamber 11 are communicated with each other so that the (state) is formed. Then, a sample is carried into the measurement chamber 11 from the preliminary exhaust chamber 12 through the communication passage 15, the gate valve is closed again, and measurement is performed in the measurement chamber 11 by X-ray photoelectron spectroscopy.

  The preliminary exhaust chamber in the present invention has the same structure as the preliminary exhaust chamber (also referred to as a sample exchange chamber) provided in various commercially available X-ray generators, and two types (120 nm to 200 nm) having different emission wavelengths. (A wavelength range of less than 200 nm and a wavelength range of 300 nm to 300 nm) and an oxygen supply means capable of supplying oxygen can be further provided.

In the present embodiment, the preliminary exhaust is used to prevent the measurement accuracy from being lost due to the reattachment of pollutants in the atmosphere by forming a low pressure or vacuum state in the preliminary exhaust chamber. Alternatively, preliminary exhaust may be performed and gas may be substituted in the room using a gas having low reactivity with oxygen to prevent reattachment of contaminants. At this time, the preliminary exhaust chamber may be in a low pressure or a vacuum state, or may be an atmospheric pressure or a pressure in the vicinity thereof.
In this case, the preliminary exhaust chamber can be provided with a replacement gas supply pipe for supplying a gas having low reactivity with oxygen into the chamber. When the gas is supplied from the replacement gas supply pipe, the preliminary exhaust chamber can be replaced with the replacement gas by exhausting with the exhaust mechanism. After the gas replacement, the room can be adjusted to an atmosphere in which oxygen exists.

The gas having low reactivity with oxygen includes an inert gas. For example, a rare gas such as nitrogen gas (N ₂ ) or argon (Ar) gas can be used.

  In addition, the measurement by the X-ray photoelectron spectroscopy in the X-ray photoelectron spectrometer (XPS apparatus) of the present invention can be performed according to a conventionally performed method and measurement conditions.

The X-ray photoelectron spectrometer of the present invention can damage even when a sample using a semiconductor material [for example, SiO ₂ film], a photocatalyst [for example TiO ₂ ], a hard film [for example, TiN film, CrN film] or the like is used. Without giving, the sample surface can be cleaned (cleaned) satisfactorily and measurement can be performed while maintaining the clean surface before measurement, and the measurement accuracy can be effectively improved regardless of the sample type.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.

(Example 1)
As an XPS device, PHI-5500MC manufactured by ULVAC-PHI was prepared. This apparatus can be connected to a preliminary exhaust chamber that allows preliminary exhaust and introduces a measurement sample, a measurement chamber that is a measurement chamber for measuring a sample, and a preliminary exhaust chamber and a measurement chamber. And a connecting path.

And the window material of two 70 mm diameter flanges installed in the preliminary exhaust chamber of this apparatus is changed to MgF _2, and a UV light source L9026 (160 nm band enhancement type; peak wavelength 160 nm) manufactured by Hamamatsu Photonics is used as one of them. On the other side, a UV light source L8858 (250 nm band enhancement type; peak wavelength 253.7 nm) manufactured by Hamamatsu Photonics Co., Ltd. was attached so that the introduced sample could be irradiated with two types of ultraviolet light having different peak wavelengths.

  In addition, an oxygen supply pipe is provided in the vicinity of the sensor unit for detecting whether or not the sample is introduced by the sample introduction mechanism provided in the preliminary exhaust chamber, as in FIG. Oxygen gas can be supplied into the exhaust chamber.

The preliminary exhaust chamber is further provided with an exhaust mechanism. The exhaust mechanism includes a rotary pump and a turbo-molecular pump, and the interior of the chamber can be preliminarily exhausted by driving these pumps.
In addition, an open / close valve is attached to the connection path connecting the pre-exhaust chamber and the measurement chamber as shown in FIG. 1, and by opening the open / close valve as necessary, the pre-exhaust chamber, the measurement chamber, Can be communicated.

  Using the above XPS apparatus, molybdenum (Mo) (manufactured by Kojundo Chemical Laboratory Co., Ltd.), which is a metal piece of 5 × 10 mm size, was introduced into the preliminary exhaust chamber as a sample using a sample introduction mechanism.

Subsequently, preliminary exhaust is performed by the exhaust mechanism of the preliminary exhaust chamber, and the pressure in the preliminary exhaust chamber is reduced to vacuum [1.33 × 10 ⁻⁵ Pa (1 × 10 ⁻⁷ torr)], and then oxygen is supplied from the oxygen supply pipe. Gas was supplied (about -0.05 atm) to make the pre-exhaust chamber an oxygen atmosphere. In this state, the metal Mo was simultaneously irradiated with two types of ultraviolet light having different wavelengths. Irradiation with ultraviolet light was performed with the irradiation time set to 180 seconds and 300 seconds to clean the metal Mo surface.

Thereafter, the rotary pump and the turbo molecular pump of the exhaust mechanism are driven to exhaust the interior of the preliminary exhaust chamber again, the oxygen in the preliminary exhaust chamber is exhausted, and the degree of vacuum is 1.33 × 10 ⁻⁵ Pa (1 × 10 ⁻⁷ torr). ) When the pressure reached the level, the valve of the connection path was opened, and the cleaned metal Mo was transported through the connection path connecting the preliminary exhaust chamber and the measurement chamber and carried into the measurement chamber. After carrying in, the measurement chamber was operated and measurement of metal Mo was started.

  Here, for each of the cleaned metal Mos with different irradiation times, the amount of carbon (%; carbon residual ratio) present on the metal Mo surface was also measured by PHI-5500MC manufactured by ULVAC-PHI. The measurement results are shown in FIG.

The measurement conditions in the above measurement chamber were as follows.
X-ray source: Mgkα ray, 1253.6 eV, 15 kV, 400 W
・ X-ray irradiation area: about 800μmφ
-Photoelectron extraction angle: 45 °
-Chamber internal pressure during measurement: 1.33 × 10 ⁻⁷ Pa (1 × 10 ⁻⁹ torr)

(Comparative Examples 1-2)
In Example 1, the cleaning of the surface of the metal Mo performed by simultaneously irradiating the metal Mo with two types of ultraviolet light having different wavelengths is performed only for the UV light source L9026 (160 nm band enhancement type) (Comparative Example 1) or the UV light source L8858. Except for using only (250 nm band enhancement type) (Comparative Example 2), the same operation as in Example 1 was performed, and the carbon residual ratio was measured in the same manner. The measurement results are shown in FIG.

  As a result of each surface analysis of metal Mo in Example 1 and Comparative Examples 1 and 2, in Example 1, compared with Comparative Examples 1 and 2, the surface of the metal Mo was clean, so that a highly accurate surface analysis was performed. I was able to do it.

1 is a perspective view showing a schematic configuration of an XPS apparatus according to an embodiment of the present invention. (A) is a spectrum when two types of ultraviolet light having different wavelengths are irradiated and cleaned, and (b) is a spectrum when cleaned by changing the time by ion sputtering. It is a graph which shows the relationship between the irradiation time of an ultraviolet light, and the carbon residual rate after irradiation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Measurement chamber 12 ... Preliminary exhaust chamber 15 ... Communication passage 17, 18 ... UV light source 21 ... Oxygen supply pipe 22 ... Exhaust pipe 23 ... Gate valve

Claims (1)

Irradiating means for irradiating light having a peak wavelength in a region having a wavelength of 120 nm or more and less than 200 nm and light having a peak wavelength in a region having a wavelength of 200 nm or more and 300 nm or less;
An oxygen supply means for supplying oxygen and an exhaust means for exhausting are provided, and differ depending on the irradiation means in the presence of oxygen formed by supplying oxygen by the oxygen supply means after exhausting or gas replacement by the exhaust means. A preliminary exhaust chamber for irradiating two light beams having a peak wavelength to clean at least a part of the sample;
A communication means having a gate valve, communicating between the preliminary exhaust chamber and the measurement chamber for measuring the sample by opening the gate valve, and capable of carrying the cleaned sample into the measurement chamber;
X-ray photoelectron spectrometer equipped with

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