JPS62152532A - Method for producing powder and hermetically closed microwave plasma reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing silicon or silicon compound powder, and to a sealed microwave plasma reactor used to carry out the method.

The object of the invention is to provide a technique that makes it possible to obtain powder with fine particle size (7 microns or less) from waste η.

Therefore, according to the invention, a powder of silicon or silicon compounds is produced, in which a gas containing silane or its derivatives is passed into a microwave plasma stream, in particular in an annular shape, and then the reaction product is cooled down. A method is provided.

The invention generally provides a micro-infrared plasma torch suitable for connection to a source of plasma-generating gas and suitable for producing a microwave plasma stream, a means for advancing reaction products throughout the plasma stream, and a torch. having an internally opening reaction casing and means for igniting a torch extending through the wall of the casing in a collapsible manner;
A closed microwave plasma reactor is provided.

Viewed from four different points of view, the present invention includes a sealed reaction casing containing an artificial passageway, an outlet sleeve and a cherry-facing orifice extending in a sealed manner into said artificial passageway. The inside of the auxiliary casing is extended in a closed manner and the inside of the sleeve is opened.
at least one gas supply tube extending into the j-line, and a T-fitting to which the tube is attached and an ffr' fift into the transversely facing orifice so as to be electrically connected to the handle of the T-fitting.
A closed microwave plasma reactor is provided, comprising an ultra-high frequency energy supply means including an end member for coupling with a sealed waveguide.

Hereinafter, with reference to the drawings, the details of the present invention will be explained.
About the shark, reveal.

The reactor generally illustrated in Figure 1 has a vertical surface.
All the elements of the reactor, consisting mainly of a double-flow microwave plasma torch 11 reaction casing and a powder collector 3, surround an internal space '8f,
- interconnected in a closed manner, v, = completely isolated from air. The torch l and the casing co are fixed to a support frame (not shown).

As clearly shown in FIG. 2, the torch l has a wedge-shaped body j, which has a right quadrilateral cross section (not shown in FIG. 2).
A stub S having a duct S is connected via an orifice.

An electrical coupling end MS material 6 is delivered to the instep of this orifice. Two concentric pipes with trunk X-X and S
The thick fr gap is □□□, and the inside of the strip body is the same @1.
Extend to group. The tube 7 is a metal outer tube, and the inner tube can be made of metal or of a heat-resistant electrically insulating material such as quartz. Above the body B+, the tube g is connected to a source of reactant gas (not shown), and the tube is connected via a transverse connecting member 9 to a source of plasma-generating gas (not shown). . The current space formed between one pipe is the one that is closed by welding above the connecting member and opens at the lower part. The handle is electrically rc connected to the end member B. The top cover 1/ that closes the private body q encloses the tube with a sealed fitting. The orifice 1 for the inflow of shielding gas
A sleeve saw with 3 is fixed around the lower opening of the rod bow, which coaxially surrounds the tube and g with a large gap. The tube 7, l#g and the lower end of the sleeve saw lie approximately in the same horizontal plane.

The casing λ is formed by a bell/Q of glass or wire mesh, and extends downwardly by a casing l of stainless steel. If the bell is made of an insulating material such as glass, it is unnecessary to provide an ignition device at and 4, and certainly ignition can be achieved externally by any known remote ignition means.

In its upper part, the bell lug is fitted with a neck 14, which has an end 7 flange/g. This neck surrounds the main body part of the sleeve saw and is fitted with a pair of horizontal flanges/9. is a glance, and a bolt (
(not shown) between the edge of the neck 14 and the sleeve/
Compress the O-ring 2/ between the outer surfaces of j.

In the illustrated example (top view 3), the bell/da is % in the downward direction.
The ignition device 15 has two removably hooked ignition devices 15 extending therein. This ignition device has a support plate 7,3 with a central orifice, which support plate is placed against the end of the facing tube 2- through the entire closing O-ring. This pressing is written horizontally!・By tightening this support et with bolts (not shown) toward the flange jK in contact with the one end flange,
I can achieve it. A collar into which a guide screw g is radially screwed is fixed to the outer surface of the support plate-3.

In the 9th year of the year, is the sleeve coordination of the poor? :fe, 2
It is fixed in the oriswiss of 3. The support plate 30 follows and extends, with a small gap, over the support plate J and the guide sleeve. This rod holds the displacement knob 3 at its inner end, has 3 grooves in its middle part that cooperate with the tip 41p of the internal screw 2g, and has an S-shaped bridge section at its inner end. kidnapping 3
It supports the insulating outer member 33 that is provided. Airtight bellows 3
5 is fixed to the end member 33 at one end and fixed to the internal sleeve cord at the other end. An adjustable stop 36 is fixed to the rod 3θ on the outside 1 of the support plate=3.

The rod 3Q is shown in Figure 3 at the point Ik (
That is, it can be displaced between a rest position, in which the bell is pulled out of the bell and the bridge member 3 is retracted into the transverse tube, and an active plasma ignition position. In this active position, the barb 30 is pushed inwardly into the barrel until the stop 36 meets the fully internally threaded collar. This displacement movement is partially translated by the guide screws 2g and f#3, but the distance between these elements is 10
Due to the angular gap of the order of 0 and the circumferential gap between the rod 30 and the orifice of the sleeve holder and the support plate 23, the end of the bridge member 3da can be brought to the end of the pipe and the S and at the same time Touching the edges of both tubes? I can do it. This method creates a short circuit that causes ignition of the microwave plasma when the torch is not supplied with plasma-generating gas and microwave (or ultra-high frequency) energy.

The double case 16 consists of an upper cylindrical part, an intermediate cylindrical part of the same diameter, and a lower conical part terminating downwards and communicating with the collecting device 3. Its upper body is clamped by flanges and sealing O-rings to the lower edge of the bell/da having the same internal diameter in a similar manner to fixing the support plate 3 to the transverse tube. 2) Case 16 is
In its upper part there is a tangentially oriented confinement gas injection orifice 3 and a cooling gas injection orifice 3g and 'ft.
fftc, get it. A hollow curved flap member 39 formed by each of the cooling gas injection orifices 3g shoulders the main body portion and the downward outlet parallel portion, and along the inner wall of the main body portion 1; t1 casing, the bell/Q extend upward into the
The outlet end section is slightly sloping towards the direction X--X and opens a short distance downwardly from the lower rudder' of the torch I. In general, the double casing 16 is provided with water cooling means that allow water to circulate downwardly into the row in the three parts of this casing between the upper inlet 4 and the lower outlet 4 (/). As a variant a includes, the water can also be circulated upwards in the case 16.The case/l is further equipped with a series of lateral conductors, which are connected to the vacuum pumper 3 and the pressure suppressor 9P dada. fI: Prepare.

The collecting device J may be any suitable powder collecting device, such as a filter. A reservoir conduit 4c3 discharging the gaseous effluent from the reactor runs from the outlet of the collection device fM3 to a station (not shown) for treating this effluent. The shielding gas, confinement gas and cooling gas are inert gases, preferably nitrogen for economic reasons. The cooling gas may contain a proportion of helium to improve its thermal conductivity.

The plasma generating gas is preferably argon.

The reactor described above operates as follows.

Initially, the air contained in the reactor is, for example, 10
m! Vacuum pump 4c3 delivers until a pressure of the order of nHg is reached, and then nitrogen or argon is introduced until a pressure of the order of 1.3 bar is reached. Presumably, after these preliminary operations have been repeated several times, the reactor becomes an inert atmosphere of 7.3 bar and contains neither oxygen nor water. During subsequent operations, the pressure was always set at approximately 1.3 bar in the casing 2 by means of the pressure regulating valve Dada, which ensured that no elements and moisture could enter the reactor. thwarted.

Plasma-generating gas and shielding gas are then supplied through the aperture and tube (sleeve), confinement gas and cooling gas are supplied through the orifice 37 and the hollow curved member 3; Super casing frequency energy is guided by wave t
irs and the end member 6, the plasma is
At the downstream end of the torch, it is ignited by an ignition product 15 in the manner previously described.

In this way, a convergent stream of plasma is obtained at the exit of the torch I. Reactant gas is then fed through the central tank S. The gas is thermally treated by the plasma as it passes through, and the reaction products are quenched in the gas flow exiting the hollow bent member 3975-.

In this way, a powder with fine particle size is formed,
Is this powder a trapped gas that follows a downward spiral path? The i-stream presses down on the inner wall of the case 16 to prevent it from being deposited. The powder is received by the inlay-3;
Depending on the nature of this collecting device, it may be continuous or
is discharged.

According to the present invention, "silane and its derivatives", hereinafter referred to as "silane", are \silicon hydride,
i.e. monosilane, disilane, trisilane and trisilane
Hydrogeno-alkyl silanes, hydrogeno-alkyl silanes, hydrogeno-alkali silanes, and mixtures of these compounds are generally considered to be cured.

As a variant, the reactive gaseous mixture can be introduced through the nine members 3, for example in order to increase the particle size of the powder produced at the mouth of the plasma stream.

Examples of using reactors include:

(a) Metathesis reactions in the gas phase, which are of particular interest in the production of refractory compositions or overlays such as silicon carbide and silicon nitride.

, 7SiH, + N2 → 513N4 (silicon nitride) +
4[2, SiH, 10CH, → 5IC (silicon carbide)
By replacing H2, N2 with NH3 or N20 or other nitrogen-containing gases or CnHm or other carbon-containing gases, as well as by redirecting SiH, with 5iCt, or other silanes, or A similar reaction can be obtained with either of them.

(1) Acetylation reaction, for example to produce silicon acetate powder. These oxides are obtained by oxidation of silane with oxygen or other oxygen-containing gases.

Thus, for example, by the reaction 5ict, +02→SiO□+coct2, 1 kl of silica powder, which is used for the preparation of gingival braces, can be produced.

(C) Reduction reaction for the production of silicon powder.

for example B i C! -, +2H2→B1+DaHct.

In this case, hydrogen can be used mixed with silane in the central tube S and/or as a component of a plasma-generating gas mixture such as argon-hydrogen.

(1 For example, monolysis reaction of silane that produces silicon powder 0
For example, 81H,→EIi+, 2H,.

In this case, the reaction gas is formed by pyrolyzed "silane" or "silanes" rather than a mixture as in the previous example.

Since the powder obtained in this way is of high quality, it can be used for the production of parts that carry extremely fine-grained gold μ-structures and thus have excellent mechanical properties, or can be used for precipitation and
Alternatively, it can be used to create extremely thin surface can breaks by projection. It is noteworthy that since the reactor is completely isolated from the surrounding atmosphere, the purity of the powder obtained depends only on the purity of the gas used.

In a variant (not shown), the tube 7 of the torch l is omitted and both the plasma-generating gas and the reactant gas are routed through a single tube g. It is also conceivable to send the reactant gas through the bra:X-ff from the location of the casing at 91I outside the torch.

[Brief explanation of drawings]

Figure 1 shows a reactor according to the invention partially in longitudinal section. The string diagram is an enlarged longitudinal sectional view of the part indicated by ■ in the Schiff diagram. Figure 3 shows Figures 12 and 11 of the part marked with ■ in Figure 41!
This is a diagram of rl&. In the drawings, l is a torch, ko is a casing, 3 is a tome, da is an annular body, 5 is a wave tube, 6 is a heat member, and 8 is a
1 is the main pipe, 9 is the horizontal connecting member, IO is the T joint, l
Ko is the sleeve, 13 is the orifice, l is the bell, 15 is the ignition device, and 16 is the case. Procedural amendment (method) January 21, 1986

Claims (1)

[Claims] 1. Process for producing powders of silicon or silicon compounds, in which a gas containing silane or its derivatives is passed into a microwave plasma stream, in particular in an annular shape, and then the reaction product is cooled. . 2. The gas is SiH_4, SiCl_4, N_2,
A method according to claim 1 for producing a powder of a refractory material such as silicon nitride or silicon carbide, which is a gaseous mixture selected from NH_3, N_2O and C_nH_m. 3. The method according to claim 1 for producing silicon oxide powder, wherein the gas contains oxygen. 4. The gas contains hydrogen and a silicon compound such as SiCl.
For producing silicon powder, which is a mixture of _4,
A method according to claim 1. 5. The method according to claim 1 for producing silicon powder, wherein the gas is a silicon compound, e.g. SiCl_4, and the plasma-generating gas is a hydrogen-containing gas, e.g. an argon-hydrogen mixture. . 6. The method according to claim 1 for producing silicon powder, wherein the reaction is monolysis of the gas. 7. Operation is achieved at a pressure slightly above atmospheric;
A method according to any one of claims 1 to 6. 8. a microwave plasma torch suitable for coupling to a source of plasma-generating gas and suitable for producing a microwave plasma stream; a means for advancing reaction products through the plasma stream; a reaction casing within which the torch opens; A sealed microwave plasma reactor having means for igniting a torch, extending through the wall of the casing in a sealed manner. 9. The reactor according to claim 8, wherein at least a portion of the casing connected to the torch is constructed of an electrically insulating material. 10. Reactor according to claim 8, wherein the casing consists of a case with passages for the circulation of cooling fluid. 11. The method of claims 8 to 10, wherein the casing includes means for injecting a converging gas stream toward a point on the axis of the torch located near the downstream end of the torch. The reactor according to any one of the items. 12. The reactor according to any one of claims 8 to 11, wherein the casing is connected to a vacuum pump. 13. Reactor according to any one of claims 8 to 12, wherein the casing is suitable for operating at a pressure higher than atmospheric pressure and is provided with a pressure regulating valve. 14. Claim 8, wherein said ignition means comprises a short circuit operated igniter slidably mounted in a sealing manner on the wall of the casing in facing relation to the downstream end of the torch. The reactor according to any one of Items 13 to 13. 15. Reactor according to any one of claims 8 to 14, wherein the casing is provided with means for injecting gas tangentially to its inner wall. 16. The torch is of dual-flow type and includes an annular passageway suitable for connection to a source of plasma-generating gas, which passageway is in a central passageway suitable for connection to a source of said reaction products. 16. A reactor according to any one of claims 8 to 15, surrounding a reactor. 17. a sealed reaction casing containing an inlet passage; a sealed auxiliary casing containing an outlet sleeve and a transverse orifice extending in a sealed manner into said inlet passage; and at least one gas supply tube extending coaxially through the sleeve, a T-fitting surrounding the tube, and a T-fitting disposed within the transverse orifice so as to be electrically connected to the handle of the T-fitting. 1. A sealed microwave plasma reactor, comprising an ultra-high frequency energy supply means including an end member for coupling with a waveguide. 18. The reactor of claim 17, wherein the auxiliary casing comprises an annular body coaxial with the outlet sleeve and with a transverse orifice. 19. Reactor according to claim 17 or 18, wherein the auxiliary casing is hermetically closed by a lid mounted on it, through which the gas supply pipe passes. 20. A reactor according to any one of claims 17 to 19, wherein the outlet sleeve comprises a gas inlet orifice.