CN113151809B

CN113151809B - Microwave plasma processing device

Info

Publication number: CN113151809B
Application number: CN202110356303.7A
Authority: CN
Inventors: 龚闯; 朱长征; 吴剑波; 蒋剑宏
Original assignee: Shanghai Zhengshi Technology Co Ltd
Current assignee: Shanghai Zhengshi Technology Co Ltd
Priority date: 2021-04-01
Filing date: 2021-04-01
Publication date: 2022-07-22
Anticipated expiration: 2041-04-01
Also published as: CN113151809A

Abstract

The invention discloses a microwave plasma processing device, which comprises a microwave source, a microwave circulator, a power regulator, a rectangular waveguide, a tuner, an antenna, a reaction box, a gas mixing system and a vacuum system, wherein the microwave source is connected with the microwave circulator, the ejection end of the microwave circulator is connected with the rectangular waveguide, the power regulator is respectively connected with the ejection end of the microwave circulator and the microwave source, the power regulator regulates the excitation power of the microwave source according to the microwave ejection power, the tuner is arranged on the side wall of the rectangular waveguide, the reaction box is arranged on the side surface of the tail end of the rectangular waveguide, the antenna is inserted into the top ends of the rectangular waveguide and the reaction box, the gas mixing system injects working medium gas into the reaction box, and the vacuum system vacuumizes the interior of the reaction box and keeps a vacuum state; the plasma cloud in the reaction chamber is subjected to internal circulation by electromagnetic force.

Description

Microwave plasma processing device

Technical Field

The invention relates to the technical field of microwave plasma processing, in particular to a microwave plasma processing device.

Background

Microwave plasma processing is a new special processing mode, and microwave plasma has high ionization degree, high electron temperature and electron density, does not contain electrode pollutants, and can not cause pollution on a microwave path even if the plasma is properly controlled, so that the microwave plasma processing method is widely used for industrial manufacturing of diamond films.

The plasma is in a cloud shape, also called as plasma cloud, in the vapor deposition process, the plasma cloud needs to be kept in a high-temperature state, once the temperature is reduced, the ionization effect is obviously reduced, the components are converted from the plasma state to the conventional gas molecular state and are not beneficial to the deposition and generation of a diamond film, the influence is mostly generated at the edge position of the plasma cloud, the boundary position of the plasma cloud and the surrounding gas is used for carrying out heat exchange, less substance exchange is carried out, the heat provided by the microwave is easy to run away to influence the stability of the plasma state, and once the phase change occurs, the diamond film at the position is not uniform and dense any more.

In the prior art, the range of plasma is usually adjusted by adjusting physical quantities or size quantities such as the height of a resonant cavity, microwave power, the height of an antenna and the like, so that a diamond film meeting the area requirement is obtained on the surface of an expected operation base.

Disclosure of Invention

It is an object of the present invention to provide a microwave plasma processing apparatus that solves the above-mentioned problems of the background art.

In order to solve the technical problems, the invention provides the following technical scheme:

a microwave plasma processing device comprises a microwave source, a microwave circulator, a power regulator, a rectangular waveguide, a tuner, an antenna, a reaction box, a gas mixing system and a vacuum system, wherein the microwave source is connected with the microwave circulator, the ejection end of the microwave circulator is connected with the rectangular waveguide, the power regulator is respectively connected with the ejection end of the microwave circulator and the microwave source, the power regulator regulates the excitation power of the microwave source according to the microwave ejection power, the tuner is arranged on the side wall of the rectangular waveguide, the reaction box is arranged on the side surface of the tail end of the rectangular waveguide, the antenna is inserted into the rectangular waveguide and the top end of the reaction box, the gas mixing system injects working medium gas into the reaction box, and the vacuum system vacuumizes the interior of the reaction box and keeps a vacuum state; the plasma cloud in the reaction chamber is subjected to internal circulation by electromagnetic force. The microwave source emits microwaves for exciting plasmas, the emitted microwaves are emitted from the microwave circulator, the emission power is adjusted by the power regulator, the microwaves advance along the rectangular waveguide, the tail end of the rectangular waveguide is closed, the microwaves are guided into the reaction box at the position of the antenna, thin working medium molecules in the microwave excitation reaction box of the reaction box enter the reaction box, an electric field is established in the reaction box by the microwaves, gas molecules in a high electric field area are converted into a plasma state, the plasmas are gathered into clusters, vapor deposition is carried out at the cluster position in the reaction box, a needed diamond film is generated, the working medium gas is fed in by the gas mixing system according to the element proportion, generally methane gas and hydrogen gas, the vacuum system is used for maintaining a vacuum environment needed by the reaction, and redundant hydrogen gas components are pumped away so as to enter new methane gas for carbon deposition. In the application, the action of electromagnetic force is specially used, the plasma cloud is enabled to move under the action of force, high heat of a plasma core is brought to an edge position, the phenomenon that the stability of the plasma cloud is influenced due to the fact that the edge position is too cold is avoided, and the carbon deposition uniformity degree and the carbon deposition effect of the edge position are further influenced.

Furthermore, the reaction box comprises a box body, a quartz window, a substrate table and a magnet, the box body is vertically arranged, the quartz window is arranged in the middle of the box body, the quartz window divides the interior of the box body into a resonant cavity and a reaction cavity, the substrate table is arranged at the bottom, away from the quartz window, of the reaction cavity, the antenna is inserted into the top of the resonant cavity, the magnet is arranged on the side wall surface of the reaction cavity, the window is formed in the quartz window, the opening area of the window in the middle of the quartz window is larger than the opening area of the quartz window on the radial outer side, the windows are circumferentially and uniformly distributed, the air mixing system is connected to the resonant cavity, and the vacuum system is connected to the bottom of the reaction cavity. Working medium is fed into the resonant cavity from the gas mixing system, then enters the reaction cavity through the quartz window, the high electric field intensity range in the reaction cavity can be controlled through the parameters such as the length of the resonant cavity inserted by an antenna, the respective heights of the resonant cavity and the reaction cavity, the section diameter of the box body and the like, the ionization effect is generated to form plasma as long as gas exists in the region reaching the ionization intensity, the middle bulge marked by a dotted line and the revolved body region with oblate edges are the agglomeration region of plasma cloud, because the main flowing direction of the working medium gas is from the resonant cavity to the reaction cavity through the window, the reacted working medium gas is pumped away from the bottom of the reaction cavity through the vacuum system, the working medium descends from a larger opening in the center of the quartz window, when the region with enough electric field intensity below is higher, the concave arc surface conical plasma cloud can be formed, and the magnet on the side wall surface of the reaction cavity promotes the movement of particles in the plasma, the temperature of the core tends to be average, so that the high-temperature position of the core is transferred to the surface position, and the cold edge position is prevented from phase change.

Furthermore, the magnetic induction line of the magnet horizontally passes through the space above the substrate table, and the magnetic induction line of the magnet rotates around the vertical central line of the box body. The horizontal magnetic induction lines can cause the particles in the plasma cloud to do an inner circulation motion: because the particles in the plasma are ionized, all the particles are free atomic nuclei and electrons, the particles are electrically neutral on a Debye scale, the particles are deviated from the expected positions under the action of a magnetic field in the process of moving from top to bottom towards the substrate platform, the stress direction is judged according to the Hall effect by the left-hand rule, the horizontal magnetic field direction and the mainly vertical equivalent current direction are horizontal and outward, the reduced equivalent currents of positive charges and negative charges are opposite, but the positive charges have large mass, the acceleration generated after the stress is small, the negative charges are electrons and have extremely small mass, the acceleration is large after the stress, the moving direction is greatly deviated, the horizontally deviated particles tend to the outer edge position of the electron cloud, namely, the core position and the edge position of the plasma cloud have particle exchange, therefore, the high temperature of the core part is transmitted to the edge position, the plasma at the edge position is prevented from being cooled, so that a stable plasma cloud area is formed, the movement speed of particles in the plasma cloud is related to the temperature of the particles, the higher the temperature is, the higher the movement speed is, the particles with the higher movement speed are, the larger the equivalent current is, after the particles are subjected to the action of a magnetic field, the larger the yawing force is, the particles are easier to run to the edge position of the plasma cloud, the particles with the lower temperature are more reserved in the core part of the plasma cloud to be subjected to 'heat preservation', namely, the particles with the higher temperature are conditionally 'picked' from the core part of the plasma cloud and are sent to the edge position of the cloud to resist being cooled, and the plasma cloud integrally tends to be more stable.

Furthermore, the magnet comprises a plurality of electromagnets, the electromagnets are uniformly distributed on the circumference of the axis by taking the vertical central line of the box body as the axis, the two ends of the electromagnet are radially arranged, and the magnet exciting coils of all the electromagnets are interlocked. When a part of coils are excited, the N pole faces to the substrate table, and the opposite electromagnets change the direction of the exciting current to enable the S pole to face to the substrate table, so that most of the magnetic induction lines in the space above the substrate table pass in the horizontal direction, when a rotating magnetic field is needed, the exciting current of each electromagnet is respectively changed to enable the NS pole to rotate, the rotating magnetic field can enable the movement circumference of particles in the plasma cloud to be distributed, the constant horizontal magnetic field can only enable the particles to move towards two directions, heat can be supplemented only in the two directions to prevent the edges from being cooled, the rotating magnetic field can enable the deflection direction of the particles to be uniformly distributed on the whole circumference angle in the overlooking visual angle, and after positive charges are subjected to the Hall effect, the self-mass is large, the yawing is not much, if the yawing is too much, the spacing between positive charges is easy to be pulled away, therefore, the Debye scale critical changes, the electrical neutrality of the plasma cloud is influenced, the yaw magnetic field rotates, the distance between the positive and negative charge centers which are separated from each other in the previous period is reduced in the next period, and the positive and negative charge centers are kept at the center of the substrate platform as a whole.

Furthermore, the vacuum system comprises a vacuum pump set and a vacuum pumping pipeline, the vacuum pump set is connected to the reaction cavity through the vacuum pumping pipeline, the end part of the vacuum pumping pipeline is provided with a vacuum pumping port, and the vacuum pumping ports are uniformly distributed on the periphery of the substrate table. And vacuumizing the evacuation port from the side of the substrate table, and evacuating the gas components subjected to vapor deposition to allow new gas with carbon elements at the quartz window to enter and form plasma.

Furthermore, the number of the evacuation ports is the same as that of the electromagnets, the evacuation ports are uniformly distributed by taking the vertical central line of the box body as an axis, at least two electromagnets are oppositely not electrified, the evacuation pipeline is provided with an electromagnetic valve at each evacuation port and independently controls the opening and the closing, the evacuation ports between the polarities of the electromagnets are opened, and the other evacuation ports are closed. Two electromagnets are not electrified to generate a magnetic field, the evacuation port is opened to serve as an evacuation position, the motion direction of particles in the plasma cloud is perpendicular to the direction of the magnetic field according to the Hall effect, namely, the particles face to the two opened evacuation ports, the gas near the two evacuation ports is an area with enough temperature compared with the edge of the plasma cloud compared with the rest positions, and if the gas at the position with weak temperature is pumped, the temperature at the position is further reduced easily to influence the stability of the boundary of the plasma cloud.

Furthermore, on-off control of the electromagnetic valve and current control of the electromagnet are performed in an interlocking mode, when the electromagnet rotates in a magnetic field through current control, the evacuation port also rotates, and the control logic is guaranteed to be completed after the interlocking control.

Furthermore, the gas mixing system comprises a gas bottle group and a gas supply pipeline, wherein the gas bottle group is used for adjusting the proportion of the working medium gas and sending the working medium gas into the resonant cavity through the gas supply pipeline.

Compared with the prior art, the invention has the following beneficial effects: according to the invention, a stable microwave environment is constructed in the reaction box through feedback control of the microwave circulator, the power regulator, the rectangular waveguide, the tuner and the antenna, after the working medium gas enters the reaction box, the working medium gas descends to undergo an ionization process, a stable plasma cloud is formed at the position of the substrate table, a horizontal magnetic field enables particles in the plasma cloud to perform yaw movement, the particles with higher temperature are subjected to larger yaw force to move to the edge of the plasma cloud, the edge is prevented from being cooled to influence the uniformity of the edge of the diamond film, the particles with higher temperature are actively selected from the core part to move to the outer layer in the plasma cloud, the integral temperature uniformity is realized, and the uniform and round edge of the diamond film subjected to vapor deposition is ensured.

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 specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic view of the structure of a reaction tank of the present invention;

FIG. 3 is view A-A of FIG. 2;

FIG. 4 is a view A-A' of FIG. 2 in another state;

FIG. 5 is a schematic perspective view of the particle and magnetic field distribution in the reaction chamber of the present invention;

in the figure: 1-microwave source, 2-microwave circulator, 3-power regulator, 4-rectangular waveguide, 5-tuner, 6-antenna, 7-reaction box, 71-box body, 711-resonant cavity, 712-reaction cavity, 72-quartz window, 721-window, 73-substrate table, 74-magnet, 8-gas mixing system, 81-gas bottle group, 82-gas supply pipeline, 9-vacuum system, 91-vacuum pump group, 92-evacuation pipeline and 921-evacuation port.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

Referring to fig. 1-5, the present invention provides a technical solution:

a microwave plasma processing device comprises a microwave source 1, a microwave circulator 2, a power regulator 3, a rectangular waveguide 4, a tuner 5, an antenna 6, a reaction box 7, a gas mixing system 8 and a vacuum system 9, wherein the microwave source 1 is connected with the microwave circulator 2, the ejection end of the microwave circulator 2 is connected with the rectangular waveguide 4, the power regulator 3 is respectively connected with the ejection end of the microwave circulator 2 and the microwave source 1, the power regulator 3 regulates the excitation power of the microwave source 1 according to the microwave ejection power, the tuner 5 is arranged on the side wall of the rectangular waveguide 4, the reaction box 7 is installed on the side face of the tail end of the rectangular waveguide 4, the antenna 6 is inserted into the top ends of the rectangular waveguide 4 and the reaction box 7, the gas mixing system 8 injects working medium gas into the reaction box 7, and the vacuum system 9 vacuumizes the inside of the reaction box 7 and keeps a vacuum state; the plasma cloud in the reaction chamber 7 is subjected to an electromagnetic force to perform internal circulation. As shown in figure 1, a microwave source 1 emits microwaves for exciting out plasma, the emitted microwaves are emitted from a microwave circulator 2, the emission power is adjusted by a power regulator 3, the microwaves advance along a rectangular waveguide 4, the tail end of the rectangular waveguide 4 is closed, the microwaves are guided into a reaction box 7 at the position of an antenna 6 and enter the microwave excitation reaction box 7 of the reaction box 7 to excite rarefied working medium molecules in the reaction box 7, an electric field is established in the reaction box 7 by the microwave, gas molecules in a high electric field area are converted into a plasma state, the plasma is gathered into clusters, carrying out vapor deposition at the agglomeration position in the reaction box 7 to generate a required diamond film, feeding working medium gas, generally methane gas and hydrogen gas, into the gas mixing system 8 according to the element proportion, maintaining the vacuum environment required by the reaction by the vacuum system 9, and pumping away the redundant hydrogen components so as to enter new methane gas for carbon deposition. In the application, the action of electromagnetic force is specially used, so that the plasma cloud moves under the action of force, high heat of a plasma core is brought to an edge position, the phenomenon that the stability of the plasma cloud is influenced due to the fact that the edge position is too cold is prevented, and the uniformity degree and the effect of carbon deposition at the edge position are further influenced.

The reaction box 7 comprises a box body 71, a quartz window 72, a substrate table 73 and a magnet 74, wherein the box body 71 is vertically arranged, the quartz window 72 is arranged in the middle position in the box body 71, the quartz window 72 divides the interior of the box body 71 into a resonant cavity 711 and a reaction cavity 712, the substrate table 73 is arranged at the bottom of the reaction cavity 712 far away from the quartz window 72, the antenna 6 is inserted into the top of the resonant cavity 711, the magnet 74 is arranged on the side wall surface of the reaction cavity 712, a window 721 is arranged on the quartz window 72, the opening area of the window 721 in the middle position of the quartz window 72 is larger than that of the radial outer side, the windows 721 are circumferentially and uniformly distributed, the gas mixing system 8 is connected to the resonant cavity 711, and the vacuum system 9 is connected with the bottom of the reaction cavity 712. As shown in fig. 2, working medium is sent into the resonant cavity 711 from the gas mixing system 8, and then enters the reaction chamber 712 through the quartz window 72, the high electric field intensity range in the reaction chamber 712 can be controlled by the parameters such as the length of the antenna 6 inserted into the resonant cavity 711, the respective heights of the resonant cavity 711 and the reaction chamber 712, the cross-sectional diameter of the box body 71, and the like, and the region reaching the ionization intensity generates ionization to become plasma as long as there is gas, as shown in fig. 2, the revolved body region of the middle bulge and the edge oblate marked by the dotted line is the cluster region of the plasma cloud, because the main direction of the flow of the working medium gas is from the resonant cavity 711 to the reaction chamber 712 through the window 721, and the bottom of the reaction chamber 712 goes through the vacuum system 9 again to draw the reacted working medium gas, the working medium descends from the larger opening in the center of the quartz window 72, and when the region with sufficient electric field intensity below is higher, the plasma cloud with a conical concave arc surface can be formed, the magnet on the side wall surface of the reaction chamber 712 promotes the movement of particles in the plasma, so that the temperature tends to be average, the high-temperature position of the core part is transferred to the surface position, and the phase change caused by the cooling of the edge position is prevented.

The magnetic induction line of the magnet 74 horizontally passes through the space above the substrate table 73, and the magnetic induction line of the magnet 74 rotates around the vertical center line of the box 71. As shown in fig. 2, 3, 5, the horizontal lines of magnetic induction can cause the particles within the plasma cloud to move in an inner cycle: because the particles in the plasma are ionized, all the particles are free atomic nuclei and electrons, the particles are neutral in Debye scale, the particles deviate from the expected positions under the action of a magnetic field in the process of moving from top to bottom towards the substrate table, the stress direction is judged according to Hall effect by left-hand rule, the horizontal magnetic field direction and the mainly vertical equivalent current direction are the horizontal and outward stress, the reduced equivalent currents of positive charges and negative charges are opposite, the stress direction is opposite, however, the positive charges have large mass, the acceleration generated after the stress is small, the negative charges are individual electrons and have extremely small mass, the acceleration is large after the stress, the movement direction is greatly deviated, the horizontally deviated particles tend to the outer edge position of the electron cloud, namely, the core position and the edge position of the plasma cloud have particle exchange, the high temperature of the core part is transmitted to the edge position, the plasma at the edge position is prevented from being cooled, so that a stable plasma cloud area is formed, the moving speed of particles in the plasma cloud is related to the temperature of the particles, the higher the temperature is, the faster the moving speed is, the higher the equivalent current of the particles at the faster moving speed is, the larger the yawing force is after the particles are subjected to the action of a magnetic field, the particles are easier to run to the edge position of the plasma cloud, the particles at the lower temperature are more remained in the core part of the plasma cloud for heat preservation, namely, the particles with the higher temperature are conditionally "picked" from the core part of the plasma cloud and are sent to the edge position of the plasma cloud to resist being cooled, and the plasma cloud is more stable on the whole.

The magnets 74 comprise a plurality of electromagnets which are circumferentially and uniformly distributed by taking the vertical central line of the box body 71 as an axis, the two ends of the electromagnets are radially arranged, and the excitation coils of all the electromagnets are interlocked. As shown in fig. 3, when a part of coils are excited, the N pole faces the substrate stage 73, and the opposite electromagnet changes the direction of the exciting current, and the S pole faces the substrate stage 73, so that most of the magnetic induction lines in the space above the substrate stage 73 pass in the horizontal direction, when the magnetic field needs to be rotated, the exciting current of each electromagnet is changed, and the NS pole is rotated, as shown in fig. 4, the rotated magnetic field can cause the movement of the particles in the plasma cloud to be distributed circumferentially, the constant horizontal magnetic field can only cause the particles to move in two directions, and can only supplement heat in the two directions to prevent the edges from being cooled, and the rotated magnetic field can cause the deflection directions of the particles to be uniformly distributed over the full angle of the circumference in the top view, and, as mentioned above, after the positive charges receive the hall effect, the self-mass is large, so the yaw is not much, if the yaw is too much, on the contrary, the distance between positive and negative charges is easy to be increased, so that the Debye scale critical is changed, the electric neutrality of the plasma cloud is influenced, the yaw magnetic field is rotated, the distance between the positive and negative charge centers which are separated from each other in the previous period is reduced in the next period, and the positive and negative charge centers are kept at the center of the substrate table as a whole.

The vacuum system 9 comprises a vacuum pump set 91 and an evacuation pipeline 92, wherein the vacuum pump set 91 is connected to the reaction chamber 712 through the evacuation pipeline 92, evacuation ports 921 are arranged at the end part of the evacuation pipeline 92, and the evacuation ports 921 are uniformly distributed around the substrate table 73. As shown in fig. 2, the evacuation port 921 is evacuated from the side of the substrate stage 73 to evacuate the gas components that have undergone vapor deposition, and allow the new gas with carbon elements at the quartz window 72 to enter into the plasma formation.

The number of the evacuation ports 921 is the same as that of the electromagnets, the evacuation ports 921 are uniformly distributed with the vertical central line of the box 71 as the axis, at least two electromagnets are oppositely not electrified, the evacuation pipeline 92 is provided with an electromagnetic valve at each evacuation port 921 and independently controlled to be opened and closed, the evacuation ports 921 between the polarities of the electromagnets are opened, and the other evacuation ports 921 are closed. As shown in fig. 3 and 4, two electromagnets are not energized to generate a magnetic field, and the evacuation port 921 here is opened as an evacuation position, and according to the hall effect, the movement direction of particles in the plasma cloud is perpendicular to the magnetic field direction, i.e. towards the two opened evacuation ports 921, and the gas near the two evacuation ports 921 is an area with sufficient temperature compared with the edge of the plasma cloud compared with the rest positions, and if the gas at the temperature weak position is pumped, the temperature at the position is easily further reduced to influence the stability of the plasma cloud boundary.

The on-off control of the solenoid valve is interlocked with the current control of the electromagnet, and when the electromagnet rotates in the magnetic field by the current control, the evacuation port 921 also rotates, and the control logic is ensured to be completed after the interlocking control.

The gas mixing system 8 includes a gas cylinder set 81 and a gas supply line 82, and the gas cylinder set 81 adjusts the proportion of the working medium gas and sends the working medium gas into the resonant cavity 711 through the gas supply line 82.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A microwave plasma processing apparatus characterized by: the processing device comprises a microwave source (1), a microwave circulator (2), a power regulator (3), a rectangular waveguide (4), a tuner (5), an antenna (6), a reaction box (7), a gas mixing system (8) and a vacuum system (9), wherein the microwave source (1) is connected with the microwave circulator (2), the ejection end of the microwave circulator (2) is connected with the rectangular waveguide (4), the power regulator (3) is respectively connected with the ejection end of the microwave circulator (2) and the microwave source (1), the power regulator (3) adjusts the excitation power of the microwave source (1) according to the microwave ejection power, the tuner (5) is arranged on the side wall of the rectangular waveguide (4), the reaction box (7) is installed on the side surface of the tail end of the rectangular waveguide (4), the antenna (6) is inserted into the top ends of the rectangular waveguide (4) and the reaction box (7), and working medium gas is injected into the reaction box (7) by the gas mixing system (8), the vacuum system (9) is used for vacuumizing the reaction box (7) and keeping the vacuum state; the plasma cloud in the reaction box (7) is subjected to internal circulation by electromagnetic force;

the reaction box (7) comprises a box body (71), a quartz window (72), a substrate table (73) and a magnet (74), the box body (71) is vertically arranged, a quartz window (72) is arranged in the middle position in the box body (71), the quartz window (72) divides the inner space of the box body (71) into a resonant cavity (711) and a reaction cavity (712), the reaction chamber (712) is provided with a substrate stage (73) at the bottom far away from the quartz window (72), the antenna (6) is inserted into the top of the resonant cavity (711), the magnet (74) is arranged on the side wall surface of the reaction cavity (712), the quartz window (72) is provided with windows (721), the opening area of the windows (721) at the middle position of the quartz window (72) is larger than that of the radial outer side, the windows (721) are uniformly distributed on the circumference, the gas mixing system (8) is connected to the resonant cavity (711), and the vacuum system (9) is connected to the bottom of the reaction cavity (712);

the magnetic induction line of the magnet (74) horizontally passes through the space above the substrate table (73), and the magnetic induction line of the magnet (74) rotates around the vertical central line of the box body (71);

the magnets (74) comprise a plurality of electromagnets, the electromagnets are uniformly distributed on the circumference by taking the vertical central line of the box body (71) as an axis, the two ends of the electromagnet are radially arranged, and the excitation coils of all the electromagnets are interlocked;

the vacuum system (9) comprises a vacuum pump set (91) and an evacuation pipeline (92), the vacuum pump set (91) is connected to the reaction cavity (712) through the evacuation pipeline (92), evacuation ports (921) are formed in the end part of the evacuation pipeline (92), and the evacuation ports (921) are uniformly distributed on the periphery of the substrate table (73);

the number of the evacuation ports (921) is the same as that of the electromagnets, the evacuation ports (921) are uniformly distributed by taking the vertical central line of the box body (71) as an axis, at least two electromagnets are opposite and are not electrified, the evacuation pipeline (92) is provided with an electromagnetic valve at each evacuation port (921) and is controlled to be opened or closed independently, the evacuation ports (921) between the polarities of the electromagnets are opened, and the rest of the evacuation ports (921) are closed.

2. A microwave plasma processing apparatus as defined in claim 1, wherein: the on-off control of the electromagnetic valve is interlocked with the current control of the electromagnet.

3. A microwave plasma processing apparatus according to claim 1, wherein: the gas mixing system (8) comprises a gas bottle group (81) and a gas supply pipeline (82), wherein the gas bottle group (81) regulates the proportion of working medium gas and the working medium gas is supplied into a resonant cavity (711) through the gas supply pipeline (82).