CN117637421A

CN117637421A - Plasma processing apparatus and processing method thereof

Info

Publication number: CN117637421A
Application number: CN202210995008.0A
Authority: CN
Inventors: 王明明; 徐朝阳
Original assignee: Advanced Micro Fabrication Equipment Inc Shanghai
Current assignee: Advanced Micro Fabrication Equipment Inc Shanghai
Priority date: 2022-08-18
Filing date: 2022-08-18
Publication date: 2024-03-01
Also published as: TW202410743A

Abstract

The invention discloses a plasma processing device and a processing method, wherein the device comprises a gas spraying device and a base which are arranged in a reaction cavity in a relative way, and a processing area is formed between the gas spraying device and the base; a moving ring surrounding the processing region, wherein an air outlet is arranged on the moving ring; and the replacement gas source is communicated with the gas outlet, and the replacement gas stored in the replacement gas source can flow into the treatment area through the gas outlet hole. According to the invention, between two adjacent treatment steps, the replacement gas is introduced into the treatment area through the gas outlet on the movable ring, so that the gas pressure in the treatment area can be rapidly increased in a short time, and when the gas extraction device extracts the residual process gas in the treatment area, the effective extraction speed of the gas extraction device can be increased, thereby accelerating the discharge of the residual process gas in the treatment area and preventing the residual process gas from affecting the treatment effect of the next treatment step. In addition, the invention does not need to modify the existing gas spraying device, and has lower cost.

Description

Plasma processing apparatus and processing method thereof

Technical Field

The present invention relates to the field of semiconductor devices and the fabrication thereof, and more particularly, to a plasma processing apparatus and a method thereof.

Background

In the existing plasma processing device, in the process of plasma processing, process gas from an external gas source enters a reaction cavity through a gas spraying device, plasma is generated after the process gas is ionized, and the plasma processing is carried out on a substrate on an electrostatic chuck arranged on a base.

In the plasma treatment process, different process gases need to be introduced into the reaction chamber when different process steps are performed, so as to execute different process steps. For example, in 3d nand etching, in order to be able to etch deposited layers of different materials, it is generally necessary to etch a specific layer by introducing a corresponding etching gas. However, when the process gas is switched, the residual process gas in the reaction chamber in the previous processing step cannot be discharged in time, which affects the plasma processing process in the next processing step.

The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art.

Disclosure of Invention

The invention provides a plasma processing device and a processing method, wherein when the last processing step is finished, replacement gas is introduced into a reaction cavity, so that the gas pressure of the reaction cavity is increased in a time gap between the two processing steps, and further the vacuumizing speed of a vacuumizing device is increased, and the process gas remained in the reaction cavity can be discharged more quickly.

In order to achieve the above object, the present invention provides a plasma processing apparatus comprising:

a reaction chamber;

the gas spraying device is positioned at the top of the reaction cavity and is used for conveying process gas into the reaction cavity;

a base which is positioned at the bottom of the reaction cavity and is opposite to the gas spraying device, wherein a treatment area is formed between the gas spraying device and the base;

a moving ring surrounding the processing region;

at least one replacement gas source positioned outside the reaction cavity, wherein the replacement gas is stored in the replacement gas source;

an air outlet is arranged on the inner surface of the movable ring, and the air outlet is communicated with the replacement air source through an air channel.

Optionally, the gas channel comprises a gas cavity, and the gas cavity is positioned in the moving ring and is communicated with the gas outlet.

Optionally, the gas chamber comprises an annular diffusion chamber.

Optionally, the annular diffusion chamber is connected to the same source of displacement gas via at least one gas inlet.

Optionally, the annular diffusion chamber communicates with different said displacement gas sources through different gas inlets.

Optionally, the gas chamber comprises at least two arc-shaped diffusion chambers, and each arc-shaped diffusion chamber is not communicated with each other.

Optionally, each of the arcuate diffusion chambers is connected to a different one of the displacement gas sources by a gas inlet.

Optionally, the gas channel further comprises a gas supply pipeline, and the gas supply pipeline is respectively communicated with the gas inlet and the replacement gas source.

Optionally, the gas supply pipeline comprises at least one gas conveying pipeline and electronic valves respectively positioned on the gas conveying pipelines; the number of the gas conveying pipelines is equal to that of the gas inlets, and the electronic valve is used for controlling the conveying quantity of the replacement gas.

Optionally, the air outlet comprises an annular air outlet hole along the circumference of the inner surface of the moving ring, and the annular air outlet hole is communicated with the annular diffusion cavity.

Optionally, the air outlet comprises at least two arc air outlet holes, and the at least two arc air outlet holes are communicated with the at least two arc diffusion cavities in a one-to-one correspondence manner.

Optionally, the air outlet comprises a plurality of round holes distributed at intervals along the circumference of the moving ring.

Optionally, the moving ring is movable between at least two positions, a high position and a low position; during plasma processing, the moving ring is lowered to a low position.

Optionally, when the moving ring is lowered to a low position, the height of the air outlet is lower than the height of the gas spraying device and higher than the height of the base.

Optionally, the gas delivery conduit comprises a hose, the hose being collapsible.

Optionally, the plasma processing apparatus further comprises: and the lifting driving piece is connected with the movable ring and used for fixing and moving the movable ring.

Optionally, the plasma processing device further comprises an air extracting device, and the air extracting device is located at the bottom of the reaction cavity.

The invention also provides a plasma treatment method based on the same inventive concept, which comprises the following steps:

placing the wafer to be processed on the base of any one of the plasma processing devices, and if the book moving ring descends to a low position;

introducing process gas into the processing area to carry out plasma processing on the wafer;

and when the current treatment step is finished, introducing replacement gas into the treatment area through the movable ring so as to accelerate the discharge of the residual process gas in the treatment area.

Optionally, the plasma processing method further comprises: before the following process steps are started, the introduction of the displacement gas into the process zone is stopped.

The invention has the following advantages:

the invention is provided with the air outlet on the movable ring and is communicated with the replacement air source through the air channel, when the current etching step is finished, the replacement air stored in the replacement air source can be introduced into the cavity of the reaction cavity through the air outlet, so that the air pressure in the reaction cavity is rapidly increased in a short time, the effective pumping speed of the air pumping device can be obviously increased when the residual process air in the reaction cavity is pumped by the air pumping device, the discharge of the residual process air in the reaction cavity is further accelerated, and the residual process air is prevented from affecting the treatment effect of the next treatment step. In addition, the movable ring is provided with the air outlet, the existing gas spraying device is not required to be modified, the structure is simple, the cost is low, and meanwhile, the worry that the replacement gas remains in the gas spraying device to dilute the next process gas is also not required.

Drawings

Fig. 1 is a schematic structural view of a plasma processing apparatus according to a first embodiment of the present invention.

Fig. 2 is a schematic plan view of the gas chamber from the gas shower end to the base end in fig. 1.

FIG. 3 is a schematic bottom view of the gas outlet from the base end to the gas shower end in accordance with one embodiment of the present invention.

Fig. 4 is a schematic bottom view of the air outlet provided in the first embodiment of the present invention.

Fig. 5 is a schematic top view of a gas chamber according to a second embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a plasma processing apparatus according to a second embodiment of the present invention.

Fig. 7 is a schematic structural diagram of a plasma processing apparatus according to a second embodiment of the present invention.

Fig. 8 is a schematic top view of a gas chamber according to a third embodiment of the present invention.

Fig. 9 is a schematic bottom view of an air outlet according to a third embodiment of the present invention.

Fig. 10 is a schematic flow chart of a plasma processing method according to an embodiment of the invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present invention is not limited to the specific embodiments disclosed below.

As described in the background section, in the process of the current plasma processing apparatus, the process gas of the previous processing step cannot be timely discharged from the reaction chamber, and remains in the processing region to affect the process of the next processing step.

In view of this, the present invention provides a plasma processing apparatus, as shown in fig. 1, comprising a reaction chamber 4 capable of being evacuated, wherein a gas shower apparatus 1 is disposed at the top of the reaction chamber 4, and a process gas source 13 is provided to charge a process gas into the reaction chamber 4 through the gas shower apparatus 1, and the gas shower apparatus 1 is used as an upper electrode. The bottom of the reaction chamber 4 is provided with a base 11 opposite to the gas spraying device 1 for bearing and fixing a wafer to be processed, the base 11 can be used as a lower electrode at the same time, and a processing area is formed between the gas spraying device 1 and the base 11. A high frequency rf power source is connected to the susceptor 11 to form an rf electric field between the upper electrode and the lower electrode to excite the process gas in the reaction chamber 4 into plasma for plasma processing the wafer.

Since the plasma is diffuse, although the plasma mostly stays in the processing region between the upper electrode and the lower electrode, once the plasma diffuses into the unprotected region of the reaction chamber 4, unnecessary etching reactions occur in the reaction chamber 4, thereby contaminating the wafer. Therefore, a moving ring 2 is arranged between the periphery of the gas spraying device 1 and the side wall of the reaction chamber 4, and the moving ring 2 can move between two positions, namely a high position and a low position under the action of the lifting driving piece 12. When the movable ring 2 descends to a low position, the movable ring 2 surrounds the processing area, so that plasma generated in the plasma processing process is limited in the processing area, and unnecessary etching reaction in the reaction cavity is avoided. When the moving ring 2 is lifted to a high position, the transfer channel 3 on the side wall of the reaction chamber 4 can be reserved for moving the wafer into or out of the reaction chamber 4.

The bottom of the reaction chamber 4 is also provided with an air extractor 5, and when the wafer is subjected to plasma treatment, the air extractor 5 is used for maintaining the vacuum state in the reaction chamber 4, so that the pressure in the reaction chamber 4 is ensured to be stable; when a certain process step in the reaction chamber 4 is completed or the wafer processing is completed, the air extractor 5 is operated at full power to extract the residual process gas and reaction byproducts in the reaction chamber 4.

The inner surface of the movable ring 2 near the processing area is provided with an air outlet 15, the air outlet 15 is communicated with a displacement air source 6 outside the reaction cavity 4 through an air channel, the displacement air source 6 stores displacement air, in some embodiments, the displacement air does not participate in plasma processing, and inert air is adopted as the displacement air. When the chamber environment needs to be cleaned or between two adjacent process steps, that is, before the last process step is finished and the next process step is started, the replacement gas source 6 introduces replacement gas into the processing area through the gas outlet 15 on the moving ring 2, so as to rapidly increase the pressure value in the chamber in a short time, and meanwhile, increase the pressure difference between the processing area and the gas extraction device 5, and when the gas extraction device 5 operates at full power to extract the residual process gas in the reaction chamber 4, the effective flow of the gas extraction device 5 can be improved, that is, more gas extraction quantity under the same extraction force can be improved, so that the discharge of the process gas can be accelerated. In addition, the movable ring 2 is provided with the air outlet 15, the existing gas spraying device 1 is not required to be modified, and the movable ring is simple in structure and low in cost.

The opening direction of the gas outlet 15 is toward the treatment area, and when the movable ring 2 is lowered to the low position, the height of the gas outlet 15 is lower than the height of the gas spraying device 1 and higher than the height of the susceptor 11. It should be noted that the process gas discharge rates are different in different regions of the process region, for example, in the horizontal direction, the region of the process region close to the gas extraction device 5 has a faster discharge rate than the region of the process region far from the gas extraction device 5; in the vertical direction, the process gas in the region of the process region near the susceptor has a faster discharge speed than the region of the process region near the gas shower apparatus 1. In order to make the process gas in the reaction chamber 4 be discharged more quickly, preferably, when the moving ring 2 is lowered to a low position, the opening direction of the gas outlet 15 is set to be towards the bottom of the gas spraying device 1, and at this time, the replacement gas can press the process gas at the top of the treatment area to move downwards while increasing the gas pressure in the reaction chamber 4, so as to accelerate the discharge of the process gas.

The gas channel comprises a gas cavity 10 positioned in the moving ring, and the gas cavity 10 is communicated with a gas outlet 15 on the moving ring 2. At least one gas inlet 14 is arranged on the gas cavity 10, and the gas inlet 14 is communicated with the replacement gas source 6. The displacement gas in the displacement gas source 6 flows into the gas cavity 10, is homogenized through the gas cavity 10, and flows into the treatment area through the gas outlet 15, so that the flow rate of the displacement gas blown out from the gas outlet 15 is uniform.

The gas channel further comprises a gas supply conduit for communicating the displacement gas source 6 with the gas chamber 10. The gas supply pipeline comprises at least one gas transmission pipeline 8 and at least one electronic valve 7 respectively positioned on at least one gas transmission pipeline 8, and the number of the gas transmission pipelines 8 is consistent with that of the gas inlets 14. One end of the gas transmission pipeline is connected with the replacement gas source 6, and the other end of the gas transmission pipeline penetrates through the cavity wall of the reaction cavity 4, extends into the reaction cavity 4 and is communicated with the gas inlet 14. The gas delivery pipe 8 comprises a bellows 9, the bellows 9 is telescopic, and the telescopic range of the bellows 9 is greater than or equal to the movable range of the movable ring 2, so as to ensure the connection stability of the gas delivery pipe and the annular cavity 10 when the movable ring 2 moves. The electronic valve 7 is used for controlling the on-off state and the gas conveying amount of the replacement gas so that the replacement gas is introduced into the processing area when the current processing step is finished, and the replacement gas is stopped from being introduced into the processing area before the next processing step is started.

The plasma processing apparatus further comprises a control device (not shown). The control device is used for controlling the operation of the electronic valve 7 so as to control the on-off of the replacement gas in each gas inlet 14. The control device is also used for controlling the operation of the lifting driving member 12 so as to control the moving ring 2 to move between at least a high position and a low position.

As shown in fig. 2, a top view of a gas chamber according to a first embodiment of the invention is provided. The gas chamber comprises an annular diffusion chamber 1001, and a gas inlet 14 is provided in the annular diffusion chamber 1001. The inlet 14 communicates with a source of displacement gas via the gas delivery conduit 8. The replacement gas in the replacement gas source 6 flows into the annular diffusion cavity 1001 through the gas inlet 14, and flows into the treatment area through the gas outlet 15 after being homogenized through the annular diffusion cavity 1001, so that the flow rate of the replacement gas blown out from the gas outlet 15 is uniform. Further, the annular surface of the annular diffusion chamber 1001 forms an angle with the horizontal surface, so that the displacement gas in the diffusion chamber 1001 is blown to the treatment area through the gas outlet 15. Preferably, the displacement gas flows through the gas outlet 15 to the bottom of the gas shower 1.

The air outlet 15 may comprise an annular air outlet hole (as shown in fig. 3) circumferentially disposed along the inner surface of the moving ring, or may comprise a plurality of circular holes 1502 (as shown in fig. 4) circumferentially spaced apart along the moving ring 2. Further, the circular holes 1502 may be uniformly distributed or unevenly distributed; the opening angles of the circular holes 1502 may be the same or different, which is not limited by the present invention. However, when the circular holes 1502 having the same opening angle are used to inject the replacement gas toward the same position in the processing region, there may be a case where the gas flows collide with each other, and preferably, one circular hole 1502 is provided in the same axial direction of the moving ring 2.

According to the invention, the gas outlet 15 is arranged on the movable ring 2 and is communicated with the replacement gas source 6 through the gas channel, when the current plasma treatment step is finished, the replacement gas stored in the replacement gas source 6 is introduced into the cavity of the reaction cavity 4 through the gas outlet 15, so that the gas pressure in the reaction cavity 4 is rapidly increased in a short time, the effective pumping speed of the gas pumping device 5 can be obviously increased when the residual process gas in the reaction cavity 4 is pumped by the gas pumping device 5, the discharge of the residual process gas in the reaction cavity 4 is further accelerated, and the residual process gas is prevented from affecting the treatment effect of the next treatment step. In addition, the opening direction of the air outlet 15 is oriented to the bottom of the gas spraying device 1, so that the air pressure in the reaction cavity 4 is increased, and meanwhile, the process gas at the top of the treatment area can be pressed to move downwards, so that the process gas at the bottom of the gas spraying device 1 is effectively discharged out of the treatment cavity.

Fig. 5 is a plan view of a gas chamber according to a second embodiment of the present invention. The difference between this embodiment and the first embodiment is that the gas chamber includes an annular diffusion chamber 1001, and a plurality of gas inlets 14 are provided on the annular diffusion chamber 1001. The multiple gas inlets 14 may be respectively connected to the same replacement gas source 6 (as shown in fig. 6) through corresponding gas delivery pipelines 8, or may be connected to different replacement gas sources 6 (as shown in fig. 7). By controlling the opening and closing degree of the electronic valve 7 on each gas conveying pipeline 8, the gas conveying amount of the replacement gas in each gas inlet 14 can be controlled, and then the flow speed and flow rate of the replacement gas output by the gas outlet 15 corresponding to the gas inlet 14 are controlled, so that the replacement gas in the region far away from the air extractor 5 in the treatment region has higher flow speed and flow rate, the process gas is driven to flow to the air extractor 5, and the discharge of the residual process gas in the treatment region is accelerated.

In addition, other structures and operation modes of each component in this embodiment are the same as those in the foregoing embodiments, and are not described in detail.

When the current treatment step is finished, the replacement gas is introduced into the reaction cavity 4 through the gas outlet on the movable ring 2, so that the gas pressure in the reaction cavity 4 is increased, and meanwhile, the effective extraction of the air extractor 5 is increased, and the discharge of the residual process gas in the reaction cavity 4 is further accelerated. In addition, the invention is provided with a plurality of gas inlets 14 on the gas cavity 10, and the output quantity of the replacement gas at the gas outlets 15 corresponding to each gas inlet 14 can be adjusted by controlling the gas transmission quantity of the replacement gas in each gas inlet 14, so as to control the sweeping direction of the process gas in the treatment area, and further enable the process gas in the area far away from the air extractor 5 in the treatment area to flow to the air extractor 5, thereby accelerating the discharge of the process gas.

As shown in fig. 8, a top view of a gas chamber according to a third embodiment of the present invention is provided. This embodiment differs from the second embodiment of the present invention in that the gas chamber 10 includes a plurality of arc-shaped diffusion chambers 1002 that are separately disposed along the circumferential direction of the moving ring, each of the arc-shaped diffusion chambers 1002 is provided with a gas inlet 14, and each of the arc-shaped diffusion chambers 1002 is connected with a gas outlet 15. In the second embodiment of the present invention, all the gas inlets 14 and the gas outlets 15 are connected to the same annular diffusion chamber 1001, and even if the gas delivery amounts of the replacement gas introduced into the respective gas inlets 14 are different, the flow rate and the flow rate of the replacement gas outputted from the respective gas outlets 15 have small differences under the uniform gas action of the annular diffusion chamber 1001. In this embodiment, each of the gas inlets 14 and the gas outlets 15 is correspondingly connected to one arc-shaped diffusion chamber 1002, and the replacement gas flowing in through the different gas inlets 14 is diffused only in the corresponding arc-shaped diffusion chamber 1002, and then is output to the processing area through the corresponding gas outlets 15. Compared with the second embodiment of the present invention, the present embodiment can better adjust the gas output of each gas outlet 15.

As shown in fig. 9, the air outlet 15 includes a plurality of arc-shaped air outlet holes 1503 distributed along the circumferential direction of the inner surface of the moving ring 2. The opening angles of the plurality of arc-shaped air outlet holes 1503 may be the same or different. For example, the opening directions of the plurality of arc-shaped air outlet holes 1503 are all towards the upper surface of the base 11, or all towards the bottom of the spraying device 1, for example, the opening directions of the air outlet holes close to the air extracting device 5 in the plurality of arc-shaped air outlet holes 1503 are towards the bottom of the spraying device 1, and the opening directions of the air outlet holes far away from the air extracting device 5 in the plurality of arc-shaped air outlet holes 1503 are towards the upper surface of the base 11. In addition, the air outlet may further include a plurality of circular holes, which is not described in detail in this embodiment.

In addition, other structures and operation modes of each component in this embodiment are the same as those in the first embodiment, and the description of this embodiment is omitted.

When the current treatment step is finished, the replacement gas is introduced into the reaction cavity through the gas outlet 15 on the movable ring 2, so that the effective extraction of the air extractor 5 is increased while the gas pressure in the reaction cavity 4 is increased, and the discharge of the residual process gas in the reaction cavity 4 is further accelerated. In addition, the gas chamber 10 of the present invention comprises a plurality of separated arc-shaped diffusion chambers 1002, each arc-shaped diffusion chamber 1002 is provided with a gas inlet 14, and the output quantity of the replacement gas at the gas outlet 15 corresponding to each gas inlet 14 can be adjusted by controlling the gas delivery quantity of the replacement gas at each gas inlet 14, so as to control the purging direction of the process gas in the treatment area, so that the process gas in the area far from the gas extraction device 5 in the treatment area flows to the gas extraction device, and the discharge of the process gas is accelerated.

Correspondingly, the invention also provides a plasma processing method which is applied to the plasma processing equipment provided in any embodiment. As shown in fig. 6, the plasma processing method comprises the steps of:

placing the wafer to be processed on the susceptor 11, and lowering the movable ring 2 to a low position;

introducing process gas into the processing area to perform plasma processing on the wafer;

when the current treatment step is finished, introducing replacement gas into the treatment area through the movable ring 2, and simultaneously, operating the air extractor 5 at full power to extract residual process gas in the treatment area;

stopping introducing the replacement gas into the treatment area before the next treatment step is started;

repeating the above steps until the wafer processing is completed.

According to the plasma processing method provided by the embodiment of the invention, when the wafer is processed by plasma, the replacement gas is introduced between two adjacent processing steps, so that the pressure value in the processing area can be increased in a short time, and meanwhile, the pressure difference between the processing area and the air extractor 5 is also increased, and the effective pumping speed of the air extractor 5 is further improved, so that the residual process gas in the reaction cavity 4 can be more quickly discharged out of the reaction cavity 4, and the influence on the processing effect of the next processing step is avoided.

In the description, each part is described in a parallel and progressive mode, and each part is mainly described as a difference from other parts, and all parts are identical and similar to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A plasma processing apparatus, comprising:

a reaction chamber;

a moving ring surrounding the processing region;

2. The plasma processing apparatus of claim 1 wherein said gas passage comprises a gas chamber located within said moving ring and in communication with said gas outlet.

3. The plasma processing apparatus of claim 2 wherein said gas chamber comprises an annular diffusion chamber.

4. The plasma processing apparatus as recited in claim 3 wherein said annular diffusion chamber is connected to the same said displacement gas source through at least one gas inlet.

5. The plasma processing apparatus of claim 3 wherein said annular diffusion chamber is connected to different said displacement gas sources through different gas inlets.

6. The plasma processing apparatus of claim 2 wherein said gas chamber comprises at least two arcuate diffusion chambers, each of said arcuate diffusion chambers not communicating with each other.

7. The plasma processing apparatus as recited in claim 6 wherein each of said arcuate diffusion chambers is connected to a different one of said displacement gas sources through a gas inlet.

8. The plasma processing apparatus according to claim 4, 5 or 7, wherein the gas passage further comprises a gas supply pipe that communicates the gas inlet and the displacement gas source, respectively.

9. The plasma processing apparatus of claim 8 wherein said gas supply conduit comprises at least one gas delivery conduit and electronic valves respectively located on said gas delivery conduit; the number of the gas conveying pipelines is equal to that of the gas inlets, and the electronic valve is used for controlling the conveying quantity of the replacement gas.

10. The plasma processing apparatus of claim 3 wherein said gas outlet comprises an annular gas outlet aperture along a circumference of an inner surface of said moving ring, said annular gas outlet aperture being in communication with said annular diffusion chamber.

11. The plasma processing apparatus as recited in claim 6 wherein said gas outlet comprises at least two arcuate gas outlet holes, at least two of said arcuate gas outlet holes in one-to-one communication with at least two of said arcuate diffusion chambers.

12. The plasma processing apparatus according to claim 1, 3 or 6, wherein the gas outlet includes a plurality of circular holes spaced apart along a circumferential direction of the moving ring.

13. The plasma processing apparatus as recited in claim 1 wherein said moving ring is movable between at least a high position and a low position; during plasma processing, the moving ring is lowered to a low position.

14. The plasma processing apparatus of claim 13 wherein the height of the gas outlet is lower than the height of the gas shower and higher than the height of the susceptor when the moving ring is lowered to a low position.

15. The plasma processing apparatus of claim 9 wherein said gas delivery conduit comprises a hose, said hose being collapsible.

16. The plasma processing apparatus according to claim 1, further comprising: and the lifting driving piece is connected with the movable ring and used for fixing and moving the movable ring.

17. The plasma processing apparatus of claim 1 further comprising an air extraction device located at a bottom of said reaction chamber.

18. The plasma processing apparatus according to claim 1, wherein the replacement gas is an inert gas.

19. A method of plasma processing, comprising:

placing a wafer to be processed on a susceptor of a plasma processing apparatus according to any one of claims 1 to 18, the moving ring being lowered to a low position,

and when the current treatment step is finished, introducing replacement gas into the treatment area through the moving ring so as to accelerate the discharge of the residual process gas in the treatment area.

20. The method as recited in claim 19, further comprising: and stopping introducing the replacement gas into the treatment area before the next treatment step is started.