JPH03271110A - Method and equipment for production of pure material - Google Patents

Abstract

PURPOSE:To enable various metals having been left contaminated to be purified to ppb level through such processes that a raw metal is vaporized and ionized, and the resulting metallic ions are separated and then solidified. CONSTITUTION:The objective equipment 1 made up of (A) a vaporizing means 4 (e.g. laser beam irradiation devices) where a raw metal 8 is heated in a non- contact state under a ultra-high vacuum (using a vacuum pump: 3) to vaporize this metal 8, (B) an ionizing means 5 (e.g. laser pulse irradiation device) where the resulting metal atoms vaporized are ionized, (C) a separating means 6 (e.g. mass separator) where the resultant metallic ions are separated taking advantage of the difference in the ratio mass/electric charge, and (D) a solidifying means 7 (made up of a bell jar 9, a cryogenic device 11 and a substrate 12 made of a high-purity metal) where the metallic ions thus separated are solidified under a ultra-high vacuum (using a vacuum pump 10).

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides an apparatus for producing a pure substance, a method for producing a pure substance,
Specifically, the present invention relates to a pure substance manufacturing apparatus and a manufacturing method thereof that manufacture a high purity substance by separating impurities from a pure substance based on the difference in the ratio between mass and charge of the substance.

<Prior Art> Conventionally, attempts have been made to improve the purification of various metal materials with the aim of improving their functional characteristics.

The most advanced pure substance manufacturing method at present is a silicon manufacturing method, and the purity of silicon deposited by this manufacturing method is about 99.9999999% (nine nines).

A method for producing high-purity silicon will be described below.

First, silica stone (S i 02), which is an ore, is heated in an electric furnace together with coke or charcoal, and metallic silicon is obtained by a reduction reaction shown by the formula (2).

The purity of silicon obtained at this stage is approximately 99.5%.

The boiling point of 5iC14 is 55°C, and the boiling point of SiHC13 is 31.8°C.

When 5iC14 or 5iHC13 purified to contain several ppm of hydrocarbons is heated together with hydrogen, thermal decomposition and hydrogen reduction result in the following formula (■).
Silicon is precipitated by the reaction (2).

SiO2+2C=Si+2co... ■Silicon used as a semiconductor must be extremely pure.

For this reason, the metallic silicon obtained as described above,
Further, by reacting with chlorine or chlorine gas, silicon tetrachloride (SjCIa) or silane trichloride (S i HCIa) gas obtained by the reaction of formula 0 or formula 0 is purified by fractional distillation.

S i +2 CI Si Cl a・◆◆・
・■S i +3HCl-1→5iHC13+H2◆・
■5iC14+2H2−-→S i +4HCl
・ ・■S j HC13+H2-1-→Si+3HC
1. ・■ At this time, if a silicon rod is placed in a reactor and heated to around 1000℃ by electricity, polycrystalline silicon will precipitate and grow around the silicon rod, and the diameter of the rod will become thicker. Polycrystalline silicon of high purity (electrically active impurity *ffi is Ippb or less) can be obtained.

A conceptual diagram of this process is shown in FIG.

As shown in this figure, metal silicon and chlorine gas react in the fluidized fluidized furnace 1 according to equation 0, and silane trichloride (SiHC) reacts with chlorine gas.
l2) is generated. This 5iHC13 is introduced into a distillation column 2, and harmful impurities are removed by utilizing the difference in boiling points to produce highly pure 5iHC13. This is mixed with high-purity hydrogen and introduced into the reduction reactor 3, and high-purity polycrystalline silicon is deposited on the silicon mandrel 5 in the quartz cylinder 4 according to the 0 formula.

<Problems to be Solved by the Invention> However, such conventional methods for producing pure substances have the following disadvantages.

In this conventional method for producing high-purity substances, the raw metal is vaporized as a predetermined compound, and then the chemical properties of the metal (
The desired pure substance and impurities were separated due to differences in distillation point, etc.).

Therefore, in this production method, if the raw metal cannot be vaporized as a compound, or if a pure substance and an impurity have similar chemical properties, for example,
When the pure substance and the impurity are transition metals or rare earth metals, a problem has arisen in that the desired pure substance and impurity cannot be separated.

As a result, a problem has arisen in that a desired high-purity substance cannot be obtained depending on the raw material metal.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an apparatus for producing pure substances and a method for producing the same, which can improve the purity of various metals whose purity has been delayed to the ppb level.

<Means for Solving the Problems> The first invention of the present application provides a vaporizing means for vaporizing the raw metal by heating the raw metal in a non-contact state under an ultra-high vacuum, and a method for vaporizing the raw metal. ionization means for ionizing the metal atoms vaporized by the ionization means; separation means for separating the plurality of metal ions generated by the ionization means based on the difference in their mass-to-charge ratio; A solidification means for solidifying under vacuum.

The second invention of the present application includes a vaporization step of vaporizing raw metal;
An ionization process in which this vaporized metal is ionized to generate multiple types of metal ions, and a voltage is applied to accelerate these multiple types of metal ions to separate them according to their mass-to-charge ratio. This is a method for producing a pure substance, which includes a separation step of separating metal ions, and a solidification step of solidifying the separated metal ions.

<Operation> In the pure substance manufacturing apparatus according to the present invention, first, the raw material metal is vaporized by the vaporization means, and the vaporized metal is ionized by the ionization means to generate a plurality of types of metal ions. Then, a voltage is applied to these multiple types of metal ions by the separation means to accelerate them, and these metal ions are separated according to the ratio of mass to charge. Then,
The separated metal ions are solidified by the solidification means.

As a result, it is possible to produce highly pure substances (for example, ppb level high purity substances) for all metals.

<Example> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual diagram showing a schematic configuration of a pure substance manufacturing apparatus according to an embodiment of the invention set forth in the first claim of the present application.

In this figure, 1 indicates a pure substance manufacturing apparatus.

This pure substance manufacturing apparatus 1 includes a bell jar 2, an ultra-high vacuum pump 3, a plurality of laser beam irradiation devices 4, a laser pulse irradiation device 5, a mass separator 6, a solidification device 7,
It consists of

The bell jar 2 is a cylindrical vacuum container made of stainless steel, and the raw metal 8 is placed inside the bell jar 2 . This bell jar 2 is equipped with a valve (not shown), and by operating this valve, air can be introduced into or shut off inside the bell jar 2.

The ultra-high vacuum pump 3 exhausts the air inside the bell jar 2 (including hydrogen, helium, etc. in the air), and reduces the degree of vacuum inside the bell jar 2 to an ultra-high vacuum (10-11 to 10-13 To
r r). As this ultra-high vacuum pump 3, for example, a cryosorption pump using a Gifford-McMahon refrigerator is used. As a result, there are fewer contaminants such as gas elements inside the bell jar 2. Hydrogen and helium are exhausted from this ultra-high vacuum container using the cryosorption effect of activated carbon in a charcoal panel, for example.

Further, gas release from the wall surface of the vacuum container is prevented by heating and oxidizing the aluminum alloy vacuum container in oxygen diluted with argon to form an oxide film on the inner wall surface. Further, the leakage is prevented by a metal seal or the like.

Note that ultra-high vacuum refers to a vacuum state of 10-8 Torr or less.

The laser beam irradiation device 4 irradiates the raw material metal (for example, silicon) 8 placed in the bell jar 2 with a laser beam and directly applies heat (heating without contacting the raw material metal 8). , multiple types of metal atoms (silicon and metals as impurities contained in the raw metal) are vaporized from the raw metal 8. As a result, the vaporized metal atoms of the plurality of types are not contaminated by the heating device (vaporization device) itself. In other words, when raw metal is heated via a boat as in the resistance heating method,
Although impurity atoms from the boat are mixed into the evaporated atoms, this non-vessel type heating device 4 can prevent this. Furthermore, it is also possible to use a high frequency induction type heating device.

As this laser beam irradiation device 4, for example, a Q-switched Nd/YAG laser, an N2 laser, or the like is used. In the former, the wavelength λ is 11060 nm and the pulse width is 15 ns, and in the latter, the wavelength λ is 337 nm and the pulse width is 10 to 20 ns.
Uses ec laser. Also, this Q switch Nd/
The YAG laser has a tube diameter of several microns, a power of 80 mJ, and a power density of 106 to 1011 W/Cm2.

In addition, as means for vaporizing the metal atoms of the raw material metal 8, there are also an electron beam irradiation device using a thermionic emission type electron beam (acceleration voltage 5 kV, beam current 103 μA),
Ion beam irradiation device (e.g. 1-2 a9Ga ions)
Acceleration at 5 kV, maximum emission current is 102 μA; Ar+ ions by duoplasmatron are accelerated at 12 kV, emission current is 103 μA).

The laser pulse irradiation device 5 irradiates a plurality of types of vaporized metal atoms with laser pulses, thereby imparting energy greater than ionization energy to the orbital electrons of the vaporized metal atoms, thereby turning them into metal ions. As the laser pulse irradiation device 5, for example, one that excites the laser medium by multiphoton resonance (wavelength is 312.3 nm, pulse radiation is 6 nsec), or one that excites the laser medium by non-resonance may be used. For the former, 100mJ
Ionization is saturated with /cm2/1 pulse, but selective ionization can be achieved in an ideal case.

In addition, the mass separator 6 accelerates the metal ions in a semicircular acceleration tube by applying a voltage to the metal ions, and multiple types of metal ions are collected by double focusing by electric field deflection and magnetic field deflection. It is something that separates. The resolution of this mass separator 60 is about M/ΔM=10,000.

The solidification device 7 selects one of the metal ions thus separated and solidifies it on the substrate, and is composed of a bell jar 9, an ultra-high vacuum pump 10, and a cryogenic device 11. Specifically, the inside of the bell jar 9 is brought into an ultra-high vacuum state (10-13 Torr) by the ultra-high vacuum pump 10,
[Cryogenic apparatus] The metal ions described above are vapor-deposited onto a substrate 12 made of a high-purity metal that has been cooled to a cryogenic temperature (-253° C.) by the cryogenic apparatus 1.

Note that this substrate is kept at an extremely low temperature (-253° C.), which is a temperature sufficient to ignore the expansion of the vapor-deposited metal in the solid.

Hereinafter, a method for producing a pure substance will be explained.

FIG. 2 is a flowchart showing each step of a method for producing a pure substance according to an embodiment of the invention described in the second claim of the present application.

First, the raw metal 8 is placed inside the bell jar 2, and the interior of the bell jar 2 is pumped to an ultra-high vacuum (10-13
T o r r) state.

Thereafter, the raw metal 8 is irradiated with a laser beam of a predetermined wavelength from the laser beam irradiation devices 4, 4 to apply heat and vaporize the raw metal 8 (step Sl). As a result,
The vaporized raw material metal 8 floats in the bell jar 2 as multiple types of metal atoms.

Next, a plurality of types of metal atoms floating in the bell jar 2 are irradiated with laser light having a shorter wavelength than that from the device 4 from the laser pulse irradiation device 5 at a high density. As a result,
Energy is given to the orbital electrons of the vaporized metal atoms, and multiple types of metal ions are generated (step S2).

Then, the metal ions are introduced into the mass separator 6 and accelerated in the semicircular acceleration tube 8 by applying a voltage to the metal ions. Then, the metal ions are separated by type by double focusing by this electric field deflection and magnetic field deflection (step S3).

Next, one of the separated metal ions is introduced into the bell jar 9 in an ultra-high vacuum state, and the metal ion is vapor-deposited (solidified) on the substrate 12 cooled to an extremely low temperature (-253°C) (step S4). .

In this way, specific metal elements can be separated, making it possible to produce thin films of highly pure pure substances (for example ppb
high-purity substances) can be produced.

In addition, as a ripple effect of producing high-purity metal materials, the possibility of discovering new physical properties of each metal material increases, as well as quantifying the influence of impurities contained in metal materials on metal elements. can be converted into

Furthermore, the production of highly pure standard samples will facilitate the analysis and quantification of each metal substance.

<Effects> As described above, according to the invention described in the first and second claims of the present application, the purity of various metals can be improved to ppb level.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing a schematic configuration of a pure substance manufacturing apparatus according to an embodiment of the invention set forth in the first claim of the present application;
The figure is a flowchart showing each step of a method for manufacturing a pure substance according to an embodiment of the invention described in the second claim of the present application, and FIG. 3 is a conceptual diagram showing a process for manufacturing high-purity polycrystalline silicon. 1... Pure substance manufacturing device, 4... Laser beam irradiation device (vaporization means), 5... Laser pulse irradiation device (ionization means), 6... ...Mass separator (separation means), 7...
...Solidification device (solidification means).

Claims (2)

[Claims] (1) A vaporization means that vaporizes the raw metal by heating the raw metal in a non-contact state under an ultra-high vacuum, and an ionization means that ionizes the metal atoms vaporized by the vaporization means. , having a separation means for separating a plurality of metal ions generated by the ionization means based on the difference in their mass-to-charge ratio, and a solidification means for solidifying the separated metal ions under ultra-high vacuum. Pure substance manufacturing equipment featuring: (2) A vaporization process that vaporizes the raw metal; an ionization process that ionizes the vaporized metal to generate multiple types of metal ions; and a voltage is applied to these multiple types of metal ions to accelerate them and calculate their mass and mass. A method for producing a pure substance, comprising: a separation step of separating these metal ions according to their charge ratio; and a solidification step of solidifying the separated metal ions.