KR101623256B1 - Mild steel vaccum chambers, manufactual method and ultrahigh vacuum charged particle analysis equipment using thereof - Google Patents

Abstract

The present invention relates to an ultrahigh vacuum particle beam analyzer sensitive to ultra-high vacuum chambers and external electromagnetic fields of a low carbon steel material. More particularly, the present invention relates to an ultra high vacuum particle beam analyzer using a low-carbon mild steel vacuum chamber, And also to a charged particle beam analyzer capable of analyzing materials and devices by maintaining ultra-high vacuum and extremely high vacuum environment. A container having a hollow pillar shape and having one side opened; And a cover coupled to the open side of the container so as to be hermetically sealed, wherein the container is accommodated with a charged particle beam analyzer, the container is made of a low carbon steel material, the inside of the container is ¹ x 10 & The ultra-high vacuum chamber of the low-carbon steel can be provided. According to this, it is possible to realize an inexpensive vacuum chamber capable of simultaneously achieving ultra-high vacuum environment and magnetic shielding.

Description

Technical Field [0001] The present invention relates to an ultra-high vacuum chamber having a low-carbon steel material, a method of manufacturing a vacuum chamber, and an ultra high vacuum load beam analysis apparatus using the vacuum chamber.

The present invention relates to an ultrahigh vacuum chamber, a method of manufacturing a vacuum chamber, and an ultrahigh vacuum charged particle beam analyzer sensitive to an external electromagnetic field. More particularly, the present invention relates to a vacuum chamber having a low carbon content and using a mild steels vacuum chamber And more particularly, to a charged particle beam analyzer capable of analyzing materials and devices by shielding a magnetic field while maintaining ultra-high vacuum and extremely high vacuum environment.

A charged particle beam analyzer controls the trajectory of a charged particle by an aligned electromagnetic field generated by a coil or an electrode. An irregularly flowing external electromagnetic field, especially a magnetic field, disturbs the trajectory of the charged particle beam and degrades the performance of the device. In order to prevent orbital disturbance by the magnetic field, the charged particle beam analyzer is generally a plate made of soft magnetic material to shield the external electromagnetic field, and surrounds the moving part of the charged particle in orbit. In addition, disturbances caused by collision with gas particles can not but be taken into account when the charged particles are in progress. In order for the charged particle to proceed without collision with the gas particles, the charged particle beam analyzing apparatus places the traveling portion of the charged particle in the vacuum chamber maintaining the vacuum state. At this time, the vacuum chamber is made of a soft magnetic material to simultaneously shield gas particles and external electromagnetic fields by the outside air.

Generally, vacuum means a state in which air and gas existing in a certain space are removed. It is impossible to have a perfect vacuum that does not exist in space, and when the pressure of gas in a certain space is lower than atmospheric pressure, it is called vacuum. Vacuum is usually vacuumed at a pressure of 1 torr at atmospheric pressure, medium vacuum at 1 torr to 10 ^-3 torr, high vacuum at 10 ^-3 torr to 10 ^-7 torr, ultrahigh vacuum at 10 ^-7 torr to 10 ^-11 torr, Below these are classified as very high vacuum. [Non-Patent Document 1]

A high-vacuum vacuum environment is generally required for a charged particle beam analyzer that studies the properties of a specimen by irradiating the specimen with a charged particle beam or by measuring the energy and angle distribution of the charged particle beam emitted from the specimen. For example, the main parts of a scanning electron microscope, a transmission electron microscope, a mass spectrometer, etc. are placed in a vacuum chamber made of stainless steel, aluminum or low carbon steel and operated under a high vacuum environment. On the other hand, electron gun of high performance electron microscope, low energy electron microscope, Auger electron spectrometer, photoelectron spectrometer, photoelectron microscope and the like have ultra high vacuum of 1x10 ^-8 mbar or less Operating environment is required.

When manufacturing a vacuum system requiring an ultra-high vacuum environment, a great deal of effort is required in selecting and processing materials in order to reduce the gas emission rate from the material itself. Vacuum chambers of ultrahigh vacuum systems are generally made of stainless steel and in special cases made of titanium or aluminum. When the charged particle beam equipment is operated in ultra-high vacuum, a plate made of Permalloly or Mu-Metal is generally formed in a vacuum chamber made of stainless steel and the electromagnetic field is shielded do. In certain cases, the ultra-high vacuum chamber may be made of permalloy or mu-metal, but the permalloy and mu-metal are expensive and difficult to obtain in a desired form, and the chamber cost is generally several times higher than that of stainless steel.

Low carbon steel with carbon content of 0.5 wt% or less in carbon steel [Non-Patent Document 2] It is inexpensive and good in workability and widely used as a pipe material. Low carbon steel is a soft magnetic material with relative permeability of several hundreds or more, and its magnetic shielding efficiency is lower than that of permalloy or mu metal which has relative permeability of several thousands or more. However, it is widely used for magnetic shielding of the measurement equipment sensitive to external electromagnetic field. In the electron microscope, it is used for magnetic shielding of the barrel and sample vacuum chamber for observing the sample with an electron beam. Low carbon steel is known to have a higher gas release rate than stainless steel. [Non-Patent Document 1] It is not used at all for ultrahigh vacuum and is used in low-cost vacuum equipment for thin film production.

U.S. Pat. No. 8,541,738 B2, SURFACE ANALYZER OF OBJECT TO BE MEASURED AND ANALYZING METHOD

 Paul A. Redhead, Foundations of Vacuum Science and Technology (John Wiley & Sons, Inc., New York, 1998).  The American Iron and Steel Institute (AISI) definition: http://www.keytometals.com/Articles/Art62.htm

The ultrahigh vacuum particle beam analyzer usually uses a stainless steel vacuum chamber to create an ultra-high vacuum environment and surrounds the main working area with a permalloy or mu metal plate in a vacuum chamber to shield the electromagnetic field. This method complicates the processing of the vacuum chamber and the magnetic shielding material separately and increases the processing cost. When the ultra-high vacuum chamber is made of soft magnetic material, the structure of the system is simplified and the processing cost is lowered. However, Permalloy Nanometal, which is known as soft magnetic material for ultrahigh vacuum, is expensive and hard to find a material suitable for processing. In addition, permalloy and mu-metal are difficult to process and weld, and polishing and coating costs are considerably high.

Accordingly, the present invention has been made to solve the above-described problems.

An object of the present invention is to provide an economical and high-performance charged particle beam analyzer using a vacuum chamber made of a low-carbon steel, which is a soft magnetic material having a low cost of materials itself and low cost of processing, welding, polishing and coating .

Hereinafter, specific means for achieving the object of the present invention will be described.

An object of the present invention is to provide a container having a hollow pillar shape and having one side opened; And a cover coupled to an open side of the container so as to be hermetically sealed, wherein a container is accommodated in the container, the container is made of a low carbon steel material, ^-7 torr or less in the ultrahigh vacuum chamber of low carbon steel.

Further, the container may be characterized by being made of a low carbon steel containing 0.5 wt% or less of carbon.

The container may also be characterized by being subjected to a chemical cleaning process.

The chemical cleaning process may further include: an organic oil removing step of removing the organic oil of the container; An inorganic oil removing step of removing the mineral oil of the container; And a decontamination step of simultaneously removing organic and inorganic contamination of the container.

And removing the surface oxide layer of the container after the step of removing the mineral oil.

And an antioxidant step of applying an antioxidant coating on the inner and outer surfaces of the container by nickel plating or chrome plating to prevent oxidation or corrosion of the container after the decontamination step .

And a flange protruding in a radial direction on an open side of the container, wherein the cover is coupled with the flange so that an open side of the container is hermetically sealed.

A metal gasket provided between the cover and the container so that an open side of the container is sealed; And a knife edge protruding toward the metal gasket at a portion where at least one of the cover and the container is provided with the metal gasket, the knife edge being engaged with one surface of the metal gasket.

An object of the present invention is to provide an ultra-vacuum vacuum chamber of a low carbon steel material according to an embodiment of the present invention; A charged particle beam emitter accommodated in the container which is an embodiment of the ultra-high vacuum chamber, the charged particle beam emitter emitting a charged particle beam; And a sample accommodated in the container and irradiating the charged particle beam emitted from the charged particle beam emitter, wherein the inside of the container is used in an ultra-high vacuum of ¹ x 10 < ^-7 > torr or less A high-vacuum, high-intensity ion beam analyzer.

Also, the charged particle beam emitter may be a field emission electron source or a Schottky emitter, a cold field emission electron source, or a photo cathode or electron electron source Or a liquid metal ion source or a gas field ion source containing gallium or the like which is an ion gun ion source or an ultrahigh vacuum photoemission spectrometer or Auger electron spectrometer electron source of an electron spectrometer, an electron beam source of a low energy electron microscope (LEEM), an electromagnetic wave source of a photoelectron microscope (PEEM), an electromagnetic wave source of a mass analyzer, .

An object of the present invention is to provide a method of manufacturing a container, which comprises: a container molding step of molding a container of low carbon steel containing 0.5 wt% or less of carbon into a column shape with one side opened; Removing organic matter oil from the container; An inorganic oil removing step of removing the mineral oil of the container; And a decontamination step of simultaneously removing organic and inorganic contaminants from the container. The present invention also provides a method of manufacturing a ultra-high vacuum chamber of low carbon steel material.

And a surface oxide layer removing step of removing the surface oxide layer of the container after the step of removing the mineral oil.

And an antioxidant step of applying an antioxidant coating on the inner and outer surfaces of the container by nickel plating or chrome plating to prevent oxidation or corrosion of the container after the decontamination step And further comprising

One of the most important components of a vacuum system is sealing, which prevents air from leaking between vacuum components and parts. O-rings made of rubber used at high vacuum or higher pressure can not be used in ultrahigh vacuum because water molecules diffuse and pass hydrophilic rubber. In ultra-high vacuum or lower pressure range, use a seal made of metal materials such as pure copper, nickel, silver or copper.

Means for solving the above-mentioned problems and solving the above-mentioned problems in a simpler and more economical way are as follows: a vacuum chamber is made of a general-purpose low carbon steel material, and then a chemical cleaning process suitable for ultrahigh vacuum and an anti- Ultra high vacuum and ultra high vacuum chambers using metal sealing, and by placing a charged particle beam analyzer in a low carbon steel vacuum chamber, it is possible to provide ultra high vacuum vacuum environment and magnetic shielding So that they can be achieved at the same time.

As described above, according to one embodiment of the present invention, it is possible to realize an inexpensive vacuum chamber capable of simultaneously achieving ultra-high vacuum environment and magnetic shielding.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and, together with the description, And shall not be interpreted.
1 is a cross-sectional view of a vacuum chamber according to a first embodiment of the present invention,
FIG. 2 is a cross-sectional view illustrating a vacuum chamber according to a second embodiment of the present invention,
3 is a side view showing a low-carbon steel vacuum chamber for performance evaluation according to an embodiment of the present invention,
Figure 4 is a graph showing a vacuum chamber vacuum test according to one embodiment of the present invention,
5 is a cross-sectional view illustrating an ultrahigh vacuum electron gun using a vacuum chamber according to an embodiment of the present invention.
6 is a sectional view showing a photoemission electron spectrometer, an Auger electron spectrometer or a mass analyzer using a vacuum chamber according to an embodiment of the present invention,
FIG. 7 is a cross-sectional view illustrating a low energy electron microscope (LEEM) using a vacuum chamber according to an embodiment of the present invention.
8 is a cross-sectional view illustrating a photoelectron microscope (PEEM) using a vacuum chamber according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following detailed description of the operation principle of the preferred embodiment of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may unnecessarily obscure the subject matter of the present invention.

The same reference numerals are used for portions having similar functions and functions throughout the drawings. Throughout the specification, when a part is connected to another part, it includes not only a case where it is directly connected but also a case where the other part is indirectly connected with another part in between. In addition, the inclusion of an element does not exclude other elements, but may include other elements, unless specifically stated otherwise.

As a carbon steel which can be used as a material of a vacuum chamber which can be used for high vacuum, ultra high vacuum and extreme high vacuum according to an embodiment of the present invention, a low carbon steel having a carbon content of 0.5 wt% steel is suitable and most low-carbon steels (mild steel or low carbon steel) are on the market. Carbon steels having a carbon content of more than 0.5 wt% may cause gas in the carbon steel to be exhausted in ultra-high vacuum, and self-disturbance may occur.

FIG. 1 is a cross-sectional view illustrating a vacuum chamber according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating a vacuum chamber according to a second embodiment of the present invention. 1 and 2, a vacuum chamber according to an embodiment of the present invention includes a container 12, 22, flanges 11, 21, a joint 13, a gasket 14, a knife edge 15, , And a cover (16). The flanges 11 and 21 may be provided at one side of the container 12 and the cover 16 may be coupled to the flanges 11 and 21 by the fastening means and the flanges 11 and 21 and the cover 16, A knife edge 15 may be formed between the gasket 14 and the knife edge 15 so that the gasket 14 is held against the knife edge 15. According to one embodiment of the present invention, the gasket 14 may be composed of a metal such as copper.

With regard to the method of manufacturing a vacuum chamber according to an embodiment of the present invention, first, a material such as a pipe, a tube, or a steel plate of a low carbon steel material is bended, ), Grinding, welding, or the like to form a container. At this time, when machining such as cutting, it is preferable to use a water-soluble cutting oil made of a mineral and an organic material. The portion of the flange 11 that connects the container to the chamber or other components is formed by joining the ready-made flange 11 made of stainless steel to the container 12 as shown in Fig. 1 to form the joint 13, As shown in FIG. 2, the low-carbon steel material may be cut so that the flange 21 and the container 22 are integrally formed. The joint 13 may be configured such that the container 12 and the flange 11 are joined to each other by welding or blazing.

Conical flat flanges 11 and 21 are suitable for the high vacuum, ultra-high vacuum, and ultra-high vacuum. In the case of cone-flange configuration, metal flange and copper metal gasket (standard type, improved type) which are widely used in high vacuum, ultra-high vacuum and ultra-high vacuum can be used without modification and can be connected immediately with general vacuum parts. Flanges can also be made using commercially available metal O-rings. The method of using the metal O-ring is to seal the metal O-ring with a well-polished metal surface instead of the knife edge 15 to penetrate the copper gasket 14.

As shown in FIGS. 1 and 2, the completed container can undergo a chemical cleaning process suitable for a high vacuum, ultra-high vacuum, and ultra-high vacuum chamber.

The chemical cleaning process includes a first step of removing the organic oil, a second step of removing the mineral oil, a third step of removing the thick and contaminated surface oxide film, and a fourth step of simultaneously removing the organic matter and the inorganic contamination can do. By this step, the polishing (oxide film reforming) is performed, the surface area is reduced, and the gas emission on the surface of the low carbon steel can be minimized.

However, the third step may be omitted if the surface contamination is not severe due to proper cutting process. When the chemical washing process is completed through the first to fourth steps, in order to prevent oxidation or corrosion of the carbon steel, the inner and outer surfaces of the prepared container are oxidized by nickel or chromium plating or the like And applying an anti-reflective coating. With such a coating, the effect of minimizing the gas emission on the low carbon steel surface is generated.

A vacuum chamber according to an embodiment of the present invention for ultrahigh vacuum and ultra high vacuum was made of a low carbon steel as described above to evaluate its exhaust performance. Vacuum performance was measured by using ultra low vacuum and ultra high vacuum chambers according to the present invention by using a material of low carbon steel (KS 3752) which is easily available and cheap in the market.

3 is a side view showing a low-carbon steel vacuum chamber for performance evaluation according to an embodiment of the present invention. As shown in FIG. 3, the low-carbon steel vacuum chamber for performance evaluation cut the low-carbon steel bar to fabricate the flange 21 and the container 22 integrally. The inner surface area is 1,600 mm ² and the outlet (exhaust) flange 21 is conplated CF 114.

4 is a graph showing a vacuum chamber vacuum test according to an embodiment of the present invention. FIG. 4 shows an exhaust curve exhausted by a turbo molecular pump of 300 l / s. The test is a measurement including a baking process at 150 ° C. for 24 hours while evacuating the vacuum chamber. The gauge for the measurement is an ion gauge that is standard in ultra-high vacuum. As shown in FIG. 5, the ultimate pressure of the carbon steel vacuum chamber according to an embodiment of the present invention was very low, i.e., 5 x ¹⁰ < ^-10 > Torr or less after 24 hours of bakeout, Is also evaluated as a sufficient value. As shown in FIG. 4, according to an embodiment of the present invention, it can be seen that a vacuum chamber for ultrahigh vacuum can be realized using low-cost low-carbon steel.

FIG. 5 shows an embodiment of a ultra-high vacuum electron gun or an ion gun employing the ultra-high vacuum ultra-vacuum chamber according to an embodiment of the present invention. In the low-carbon steel vacuum chamber, an electron source or ion source 31, (32), and a ceramic (33) for high voltage insulation can be provided to generate an electron or an ion beam. The charged particle beam lens 32 for focusing an electron beam or an ion beam can use both an electrostatic lens using an electric field and a magnetic lens using a magnetic field. As the electron source, a field emission electron source or a Schottky emitter, a cold field emission electron source, a photo cathode or photoelectron electron source, A liquid metal ion source including gallium or the like, a gas field ion source, or the like can be used.

FIG. 6 shows an embodiment of a low-carbon steel ultrahigh vacuum vacuum chamber according to an embodiment of the present invention applied to a photoemission electron spectrometer or an Auger electron spectrometer, An electromagnetic wave source 42 including an electron spectrometer 41, an X-ray, and ultraviolet rays, and a sample holder 43 for supporting and transporting and rotating the sample to be observed are provided, And the generated electrons are analyzed by an electron spectroscope (energy analysis) to analyze the electronic structure and atomic structure of the sample.

FIG. 6 is an embodiment of a mass analyzer employing a low-carbon steel ultra-high vacuum chamber according to an embodiment of the present invention. The low-carbon steel container 22 may include an electromagnetic wave, an ion beam, or the like. A mass analyzer 41 and a sample holder 43 for supporting and transporting and rotating the sample to be observed are provided so as to form an electromagnetic wave beam such as a laser emitted from a source or an atom, Or scattered ions can be analyzed to analyze the components of the sample, the atom-molecule structure, and the like.

FIG. 7 is an embodiment of a low energy electron microscope (LEEM) employing a low-carbon steel ultra-high vacuum chamber according to an embodiment of the present invention. In the low-carbon steel vessel 22, an electron beam source 51, An electron beam lens system 52 composed of a plurality of electron beam lenses, a sample holder 53 for supporting and transporting and rotating the sample to be observed, and a screen 54 for observing the electron beam image are provided to irradiate electrons to the sample, The surface shape of the sample and the like can be analyzed.

FIG. 8 is an embodiment of a photoelectron microscope (PEEM) employing a low-carbon steel ultra-high vacuum chamber according to an embodiment of the present invention. In the low-carbon steel vessel 22, an electromagnetic wave including X- An electron beam lens system 62 composed of a plurality of electron beam lenses, a sample holder 63 for supporting and transporting and rotating the sample to be observed, and a screen 64 for observing an electron beam image are provided, The surface shape and the electronic structure of the sample can be analyzed by imaging the electrons generated by irradiation.

As described above, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

11: Flange
12: container
13:
14: Gasket
15: Knife edge
21: Flange
22: container
31: Electron source or ion source
32: charged particle beam lens
33: Ceramics for high-voltage insulation
41: Electron spectrometer or mass analyzer.
42: an electromagnetic wave source including an X-ray, an ultraviolet ray, a visible light, a laser, etc., an electron source or an ion source
43: Sample holder
51: electron beam source
52: Electron beam lens system for LEEM
53: Sample holder
54: Screen
61: electromagnetic wave source
62: Electron beam lens system for PEEM
63: Sample holder
64: Screen

Claims (13)

A container having a hollow pillar shape and having one side opened; And
A cover coupled to an open side of the container so as to be hermetically sealed;
Lt; / RTI >
A charged particle beam analyzer is housed in the vessel,
The container is made of a low carbon steel material,
The inside of the vessel is used in ultra-high vacuum of ¹ x 10 < ^-7 > torr or less,
The container is subjected to a chemical cleaning process,
The chemical cleaning process comprises:
Removing organic matter oil from the container;
An inorganic oil removing step of removing the mineral oil of the container; And
A decontamination step of simultaneously removing organic and inorganic contamination of the container;
Wherein the vacuum chamber is made of a low-carbon steel material.
The method according to claim 1,
Characterized in that the container is made of a low carbon steel containing 0.5 wt% or less of carbon.
delete delete The method according to claim 1,
After the step of removing the mineral oil,
A surface oxide layer removing step of removing the surface oxide layer of the container;
Wherein the vacuum chamber is a vacuum chamber.
The method according to claim 1,
After the decontamination step,
An antioxidant step of applying an antioxidant coating to the inner and outer surfaces of the container by nickel plating or chromium plating to prevent oxidation or corrosion of the container;
Wherein the vacuum chamber is a vacuum chamber.
The method according to claim 1,
A flange protruding in a radial direction on an open side of the container;
Further comprising:
Wherein the cover is coupled with the flange such that an open side of the container is sealed. ≪ Desc / Clms Page number 13 >
The method according to claim 1,
A metal gasket provided between the cover and the container so that an open side of the container is sealed; And
A knife edge protruding toward the metal gasket at a portion where at least one of the cover and the container is provided with the metal gasket, the knife edge being engaged with one surface of the metal gasket;
Wherein the vacuum chamber is a vacuum chamber.
An ultra-high vacuum chamber of low carbon steel according to claim 1;
A charged particle beam emitter accommodated in the container which is an embodiment of the ultra-high vacuum chamber, the charged particle beam emitter emitting a charged particle beam; And
A sample accommodated in the container and irradiating the charged particle beam emitted from the charged particle beam emitter;
/ RTI >
Wherein the inside of the vessel is used in ultra-high vacuum of ¹ x 10 < ^-7 > torr or less.
10. The method of claim 9,
The charged particle beam emitter
A field emission electron source or a Schottky emitter of a electron gun, a cold field emission electron source or a photo cathode electron source,
A liquid metal ion source or a gas field ion source including gallium or the like, which is an ion gun ion source,
An electromagnetic wave source of a ultra-high vacuum photoemission spectrometer or an Auger electron spectrometer,
An electron beam source of a low energy electron microscope (LEEM)
An electromagnetic wave source of a photoelectron microscope (PEEM)
Wherein the analyzer is an electromagnetic wave source or an ion source of a mass analyzer.
A container forming step of forming a low-carbon steel container containing not more than 0.5 wt% of carbon into a column shape with one side opened;
Removing organic matter oil from the container;
An inorganic oil removing step of removing the mineral oil of the container; And
A decontamination step of simultaneously removing organic and inorganic contamination of the container;
Wherein the vacuum chamber is formed of a low-carbon steel material.
12. The method of claim 11,
After the step of removing the mineral oil,
A surface oxide layer removing step of removing the surface oxide layer of the container;
The method of claim 1, further comprising:
12. The method of claim 11,
After the decontamination step,
An antioxidant step of applying an antioxidant coating to the inner and outer surfaces of the container by nickel plating or chromium plating to prevent oxidation or corrosion of the container;
The method of claim 1, further comprising:

Images