Radio frequency plasma generating device with radial confinement magnetic field

Abstract

The invention discloses a radio frequency plasma generating device with a radial confinement magnetic field, and belongs to the technical field of plasma generating devices. Comprising a plasma generation area and a diffusion area which are vertically distributed and communicated, a quartz glass cover is arranged outside the plasma generation area, a water-cooling shielding device is arranged in the quartz glass cover, a magnet exciting coil is arranged outside the quartz glass cover, a quartz shell is arranged outside the diffusion area, and an outer annular magnet is fixedly arranged on the periphery of the quartz shell in a sleeving mode. An inner annular magnet matched with the outer annular magnet is fixed to the inner bottom of the quartz tube, and the bottom end of the quartz glass cover is fixedly connected with the top end of the quartz shell. The beneficial effects of the invention are that magnetic field configuration is optimized, and an induced potential field generated by electron cyclotron motion and an external constraint magnetic field are mutually counteracted; lateral diffusion of electron beams is effectively inhibited, spatial non-uniformity of plasma density is remarkably reduced, and the electron beams can be highly and uniformly diverged and distributed in a whole plasma area.

Description

Technical Field

[0001] The invention relates to a radio frequency plasma generating device with a radial confined magnetic field, belonging to the technical field of plasma generating devices. Background Art

[0002] Inductively coupled plasma sources (ICPs) are a typical type of radio frequency plasma generator, widely used in fields such as semiconductor micromachining and functional thin film deposition. In the diffusion and extraction zones of a plasma system, radial potential gradients form, creating an electric field within the plasma. In ICP devices, E×B drift (E cross B drift) is a collective motion phenomenon caused by charged particles (such as electrons or ions) under the influence of the simultaneous presence of an electric field (E) and a magnetic field (B). When the device's electric field interacts with the axial magnetic field, E×B drift occurs. Ultimately, this phenomenon causes electrons and ions to accumulate near the upper and lower walls, generating a Hall effect potential difference in the radial direction of the plasma. This drift can cause the electron beam to spiral and diverge during its motion, leading to spatially uneven plasma density distribution, decreased plasma stability, reduced energy transfer efficiency, and increased losses. Summary of the Invention

[0003] In order to solve the defects of the prior art, the purpose of the present invention is to provide a radio frequency plasma generating device with a radial confining magnetic field to improve the uniformity of the spatial distribution of plasma density.

[0004] The technical solution of the present invention is: a radio frequency plasma generator with a radial confined magnetic field, comprising a plasma generating zone and a diffusion zone distributed and connected in an upper and lower manner, a quartz glass cover provided outside the plasma generating zone, a water-cooling shielding device provided inside the quartz glass cover, an excitation coil provided outside the quartz glass cover, a quartz shell provided outside the diffusion zone, an outer ring magnet fixedly sleeved on the outer periphery of the quartz shell, a quartz tube passing through the quartz glass cover and extending to the inner bottom of the quartz shell, a cover plate welded and fixed to the upper portion of the quartz tube, the quartz tube passing through the center of the cover plate, the outer periphery of the cover plate being sealedly connected to the top of the quartz glass cover, an inner ring magnet cooperating with the outer ring magnet fixedly fixed to the inner bottom of the quartz tube, and the bottom end of the quartz glass cover being fixedly connected to the top of the quartz shell.

[0005] The water-cooled shielding device is a water-cooled Faraday shielding device, which includes a Faraday mesh cover, and a cooling water channel is fixed on the Faraday mesh cover.

[0006] The inlet and outlet ends of the cooling water channel are located outside the quartz glass cover.

[0007] The quartz glass cover, the quartz housing, the quartz tube, the outer annular magnet and the inner annular magnet are coaxial.

[0008] The outer annular magnet and the inner annular magnet are arranged at the same height.

[0009] The bottom of the quartz shell is open.

[0010] An annular groove is provided on the outer periphery of the quartz shell, and the outer annular magnet is fixed on the quartz shell through the annular groove.

[0011] The beneficial effects of the present invention are: optimizing the magnetic field configuration, the induced electric potential field generated by the electron cyclotron motion and the external confining magnetic field offset each other; effectively suppressing the lateral diffusion of the electron beam, and significantly reducing the spatial inhomogeneity of the plasma density, so that the electron beam can achieve a highly uniform divergent distribution in the entire plasma area. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Structural diagram of the present invention.

[0013] The reference numerals in the figure are as follows: 1, quartz glass cover, 2, Faraday mesh cover, 3, cooling water channel, 4, inlet end, 5, outlet end, 6, excitation coil, 7, quartz shell, 8, outer ring magnet, 9, quartz tube, 10, cover plate, 11, inner ring magnet. DETAILED DESCRIPTION

[0014] The following is combined with Figure 1 The present invention will be further described:

[0015] A radio frequency plasma generator with a radially confined magnetic field includes a plasma generating region and a diffusion region that are distributed and connected in an upper and lower manner. A quartz glass cover 1 is provided outside the plasma generating region, and a water-cooled shielding device is provided inside the quartz glass cover 1 to achieve an electromagnetic shielding effect and accelerate internal heat dissipation through cooling. An excitation coil 6 is provided outside the quartz glass cover 1, and a quartz shell 7 is provided outside the diffusion region. An annular groove is provided on the outer periphery of the quartz shell 7, and an outer annular magnet 8 is fixed to the quartz shell 7 through the annular groove. A quartz tube 9 passes through the quartz glass cover 1 and extends to the inner bottom of the quartz shell 7. A cover plate 10 is welded and fixed to the upper portion of the quartz tube 9, and the quartz tube 9 passes through the center of the cover plate 10. The outer periphery of the cover plate 10 is sealed and connected to the top of the quartz glass cover 1. An inner annular magnet 11 that cooperates with the outer annular magnet 8 is fixed to the inner bottom of the quartz tube 9. The outer annular magnet 8 and the inner annular magnet 11 are arranged at the same height. The bottom end of the quartz glass cover 1 is fixedly connected to the top of the quartz shell 7, and the bottom of the quartz shell 7 is open. The quartz glass cover 1, quartz housing 7, quartz tube 9, outer annular magnet 8, and inner annular magnet 11 are coaxial, and the magnetic field equipotential lines are distributed in concentric circles, forming a radially uniform magnetic field distribution. In this optimized magnetic field configuration, due to the change in magnetic field configuration, the induced electromotive force field generated by the electron cyclotron motion and the external confining magnetic field cancel each other out. On the one hand, this effectively suppresses the lateral diffusion of the electron beam, and on the other hand, the spatial inhomogeneity of the plasma density is significantly reduced, enabling the electron beam to achieve a highly uniform divergent distribution throughout the entire plasma region.

[0016] The water-cooled shield device is a water-cooled Faraday shield device, comprising a Faraday cage 2 on which a cooling water channel 3 is arranged. The inlet end 4 and outlet end 5 of the cooling water channel 3 are located outside the quartz glass cage 1. Cooling water enters the cooling water channel 3 from the inlet end 4 outside the quartz glass cage 1, and the flowing cooling water removes heat.

[0017] By systematically optimizing the geometry of conventional radio frequency plasma sources, a ring-shaped electrode design was adopted instead of the traditional flat-plate electrode structure. This created a uniformly diffuse radial confining magnetic field within the reaction chamber. By adjusting the geometry of the existing ICP radio frequency ion source, the confining magnetic field configuration was altered. In this optimized magnetic field configuration, the induced potential difference generated by electrons in the magnetic field forms a dynamic equilibrium with the magnetic field distribution, thereby canceling each other out. This effectively suppresses the instability caused by E×B drift and enables the electron beam to diverge uniformly throughout the entire plasma region.

[0018] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A radio frequency plasma generating device with a radial confining magnetic field, characterized in that: The invention comprises a plasma generating area and a diffusion area which are distributed and connected in an upper and lower direction. A quartz glass cover (1) is provided outside the plasma generating area, a water-cooling shielding device is provided inside the quartz glass cover (1), an excitation coil (6) is provided outside the quartz glass cover (1), a quartz shell (7) is provided outside the diffusion area, an outer ring magnet (8) is fixedly sleeved on the outer periphery of the quartz shell (7), a quartz tube (9) passes through the quartz glass cover (1) and extends to the inner bottom of the quartz shell (7), a cover plate (10) is welded and fixed to the upper part of the quartz tube (9), the quartz tube (9) passes through the center of the cover plate (10), the outer periphery of the cover plate (10) is sealed and connected to the top of the quartz glass cover (1), an inner ring magnet (11) which matches the outer ring magnet (8) is fixed on the inner bottom of the quartz tube (9), and the bottom end of the quartz glass cover (1) is fixedly connected to the top of the quartz shell (7).

2. The radio frequency plasma generating device with a radial confinement magnetic field according to claim 1, characterized in that: The water-cooled shielding device is a water-cooled Faraday shielding device, comprising a Faraday mesh cover (2), on which a cooling water channel (3) is arranged.

3. The radio frequency plasma generating device with a radial confining magnetic field according to claim 2, characterized in that: The inlet end (4) and the outlet end (5) of the cooling water channel (3) are located outside the quartz glass cover (1).

4. The radio frequency plasma generating device with a radial confining magnetic field according to claim 1, characterized in that: The quartz glass cover (1), the quartz housing (7), the quartz tube (9), the outer annular magnet (8) and the inner annular magnet (11) are coaxial.

5. The radio frequency plasma generating device with a radial confining magnetic field according to claim 1, characterized in that: The outer annular magnet (8) and the inner annular magnet (11) are arranged at the same height.

6. The radio frequency plasma generating device with a radial confining magnetic field according to claim 1, characterized in that: The bottom of the quartz housing (7) is open.

7. The radio frequency plasma generating device with a radial confining magnetic field according to claim 1, characterized in that: An annular groove is provided on the outer periphery of the quartz housing (7), and the outer annular magnet (8) is fixed on the quartz housing (7) via the annular groove.

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