Gas uniformizing and mixing structure

Abstract

The invention provides a gas uniformizing and mixing structure. The gas uniformizing and mixing structure comprises an upper spraying plate, a baffle and a spraying plate which are sequentially arranged from top to bottom. The baffle is provided with a horizontal plate and an annular ring, the annular ring is arranged along the circumference of the horizontal plate, the upper surface of the annular ring is connected with the lower surface of the upper spraying plate, and the upper spraying plate and the baffle form a first gas uniformizing and mixing cavity; a plurality of vent holes are formed in the horizontal plate; a plurality of baffle side wall exhaust holes are formed in the side wall of the annular ring; and the spraying plate and the baffle plate form a second gas uniformizing and mixing chamber.

Description

Technical Field

[0001] The invention relates to semiconductor process equipment, and in particular to a uniform gas mixing structure. Background Art

[0002] In the prior art, the gap of the uniform gas mixing structure used for thin film deposition is large. During the execution of the process recipe, the gap will be filled when the precursor is injected. The gas retained at the edge will cause a dead zone, thereby affecting the efficiency of the precursor entering the shower plate. The concentration of the precursor in the dead zone will increase indefinitely, which may easily cause the edge of the deposited film to thicken, thereby making the uniformity within the film worse. In addition, the uneven distribution of the purge gas will also lead to uneven cleaning in the cavity, which may easily cause local particle risks.

[0003] In addition, when the process cannot meet the requirements and the spray plate hole design needs to be improved, the flow field and RF distribution will change at the same time, which greatly increases the difficulty of problem analysis. Summary of the invention

[0004] In order to overcome the defects of the prior art, the present invention provides a uniform gas mixing structure.

[0005] The uniform gas mixing structure comprises a spray upper plate, a baffle plate and a spray plate which are arranged in sequence from top to bottom.

[0006] The baffle plate comprises a horizontal plate and an annular ring, the annular ring is arranged along the circumference of the horizontal plate, the upper surface of the annular ring is connected to the lower surface of the spray upper plate, and the spray upper plate and the baffle plate form a first uniform gas mixing chamber. The horizontal plate is provided with a plurality of vents. The side wall of the annular ring is provided with a plurality of baffle side wall exhaust holes.

[0007] The spray plate and the baffle plate form a second uniform gas mixing chamber.

[0008] In one embodiment, the shower plate has a shower disc and a side ring; the side ring is arranged along the circumference of the shower disc; the upper surface of the side ring is connected to the lower surface of the shower upper plate; the shower plate also has an upper electrode for forming radio frequency plasma.

[0009] In one embodiment, the spray plate is provided with a plurality of spray holes; the side wall of the side ring is provided with a plurality of spray plate side wall exhaust holes; the radius of the side ring is greater than the radius of the annular ring; a first gap is formed between the side ring and the annular ring as part of the second uniform gas mixing chamber; a second gap is formed between the side ring and the side wall of the reaction chamber as part of the reaction chamber.

[0010] In one embodiment, the plurality of exhaust holes on the baffle sidewalls are evenly distributed along the circumferential direction.

[0011] In one embodiment, the plurality of exhaust holes on the side wall of the shower plate are evenly distributed along the circumferential direction.

[0012] In one embodiment, the spray upper plate has an air inlet, and the air inlet is located at the center of the spray upper plate, and the gas enters the first uniform gas mixing chamber from the air inlet.

[0013] In one embodiment, after the gas enters the first uniform gas mixing chamber from the air inlet of the spray upper plate for uniform gas mixing, it is output downward from the multiple air vents of the horizontal plate to the second uniform gas mixing chamber. At the same time, the gas is also radially output from the multiple baffle side wall exhaust holes of the annular ring to the first gap of the second uniform gas mixing chamber.

[0014] In one embodiment, after the gas enters the second uniform gas mixing chamber from the multiple air holes of the horizontal plate and the multiple exhaust holes on the baffle side wall, it is output downward from the spray hole to the reaction chamber. At the same time, the gas is also output radially from the exhaust holes on the side wall of the spray plate to the second gap in the reaction chamber.

[0015] In one embodiment, the ratio of the flow resistance of the baffle plate to the flow resistance of the shower plate is maintained within a range, so that the coupling between the gas flow formed by the gas and the radio frequency plasma is released.

[0016] In one embodiment, the range is 5:1 to 15:1.

[0017] The uniform gas mixing structure of the present invention has the following beneficial technical effects:

[0018] First, the baffle has holes on the side for exhaust, which reduces the dead zone caused by trapped gas at the edge and greatly improves the stability of the equipment.

[0019] Secondly, the side of the spray plate is opened for exhaust, which reduces the dead zone caused by trapped gas at the edge, improves the uniformity within the piece and the stability of the equipment; at the same time, it can improve the cleaning efficiency and improve the performance of cavity particles.

[0020] Third, the flow resistance ratio of the baffle plate to the spray plate is maintained in the range of 5:1 to 15:1, the gas uniformity efficiency of the baffle plate is increased, the gas uniformity effect of the spray plate is reduced, and the coupling between the RF plasma and the airflow is released. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above invention content and the following specific embodiments of the present invention will be better understood when read in conjunction with the accompanying drawings. It should be noted that the accompanying drawings are only examples of the claimed invention. In the accompanying drawings, the same reference numerals represent the same or similar elements.

[0022] Figure 1 A cross-sectional view of a homogenous gas mixing structure according to an embodiment of the present invention is shown;

[0023] Figure 2 A front view of a homogenous gas mixing structure according to an embodiment of the present invention is shown;

[0024] Figure 3 A schematic diagram showing the gas flow direction of a uniform gas mixing structure according to an embodiment of the present invention;

[0025] Figure 4A The process repeatability of the traditional gas homogenization structure is shown;

[0026] Figure 4B The process repeatability of the uniform gas mixing structure according to an embodiment of the present invention is shown;

[0027] Figure 5 A schematic diagram showing the gas flow direction of a uniform gas mixing structure according to an embodiment of the present invention;

[0028] Figure 6 An experimental effect diagram of a uniform gas mixing structure according to an embodiment of the present invention is shown;

[0029] Figure 7 The choking flow distribution and plasma distribution of the uniform gas mixing structure according to one embodiment of the present invention are shown;

[0030] Figure 8 The choking flow distribution and plasma distribution of the uniform gas mixing structure according to one embodiment of the present invention are shown;

[0031] Fig. 9 A schematic diagram showing the relationship between film thickness (THK) and refractive index (RI) according to an embodiment of the present invention is shown, wherein the flow resistance ratio of the baffle plate to the shower plate is less than 5:1;

[0032] Fig.10 A schematic diagram showing the relationship between film thickness and refractive index according to an embodiment of the present invention is shown, wherein the flow resistance ratio of the baffle plate to the shower plate is in the range of 5:1 to 15:1. DETAILED DESCRIPTION

[0033] The detailed features and advantages of the present invention are described in detail in the specific embodiments below, and the content is sufficient to enable any person skilled in the art to understand the technical content of the present invention and implement it accordingly, and according to the description, claims and drawings disclosed in this specification, those skilled in the art can easily understand the relevant purposes and advantages of the present invention. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this embodiment. On the contrary, the purpose of introducing the invention in conjunction with the embodiment is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, many specific details will be included in the following description. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description.

[0034] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal" and "vertical" used in the following description should be understood as the directions shown in the paragraph and the related drawings. Such relative terms are only used for the convenience of description and do not mean that the device described therein must be manufactured or operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0036] It is understood that although the terms "first", "second", "third", etc. may be used herein to describe various components, channels, components, regions, layers and / or parts, these components, channels, components, regions, layers and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, channels, components, regions, layers and / or parts. In addition, the terms "first", "second", "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0037] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0038] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0039] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0040] Figure 1 FIG. 2 shows a cross-sectional view of a homogenous gas mixing structure according to an embodiment of the present invention. Figure 1 As shown, the uniform gas mixing structure of the present invention includes a spray upper plate 101 , a baffle 102 and a spray plate 103 .

[0041] The spray upper plate 101 has an air inlet 104. The air inlet 104 is located at the center of the spray upper plate. Gas enters the gas homogenizing chamber from the air inlet 104.

[0042] The baffle 102 is located below the spray upper plate 101 , and is used to perform gas homogenization and gas mixing on the gas from the spray upper plate 101 , thereby further improving the gas homogenization and gas mixing efficiency.

[0043] The baffle 102 has a horizontal plate 109 and an annular ring 110. The annular ring 110 is arranged along the circumference of the horizontal plate 109. The upper surface of the annular ring 110 is connected to the lower surface of the spray upper plate 101. The spray upper plate 101 and the baffle 102 form a first uniform gas mixing chamber. The horizontal plate 109 of the baffle 102 is provided with a plurality of vents 107, and the annular ring 110 is provided with a plurality of baffle side walls (see Figure 2 ).

[0044] The spray plate 103 is located below the baffle 102. The spray plate 103 has a spray disc 111 and a side ring 112. The side ring 112 is arranged along the circumference of the spray disc 111. The upper surface of the side ring 112 is connected to the lower surface of the spray upper plate 101. The spray plate 103 and the baffle 102 form a second uniform gas mixing chamber. The spray disc 111 of the spray plate 103 has a plurality of spray holes 108, and the side wall of the side ring 112 has a plurality of spray plate side wall exhaust holes (see Figure 2 ).

[0045] The shower plate 103 also has an upper electrode for forming radio frequency plasma together with the lower electrode of the heating disk.

[0046] The gas enters the first gas-homogenizing chamber from the gas inlet 104 of the spray upper plate 101 for gas-homogenizing and gas-mixing, and then further enters the second gas-homogenizing chamber for gas-homogenizing and gas-mixing, and finally the gas is output from the spray holes of the spray plate 103 .

[0047] Figure 2 FIG. 2 shows a front view of a homogenous gas mixing structure according to an embodiment of the present invention. Figure 2 As shown, the uniform gas mixing structure of the present invention includes a spray upper plate 101 , a baffle 102 and a spray plate 103 .

[0048] The spray upper plate 101 has an air inlet 104. The air inlet 104 is located at the center of the spray plate. Gas enters the gas homogenizing chamber from the air inlet 104.

[0049] The baffle 102 is located directly below the spray upper plate 101 . The baffle 102 is located between the spray upper plate 101 and the spray plate 103 , dividing the uniform gas mixing space into two parts, so as to further improve the uniform gas mixing efficiency.

[0050] The baffle 102 has a horizontal plate 109 and an annular ring 110. The annular ring 110 is arranged along the circumference of the horizontal plate 109. The upper surface of the annular ring 110 is connected to the lower surface of the spray upper plate 101. The spray upper plate 101 and the baffle 102 form a first uniform gas mixing chamber.

[0051] The horizontal plate 109 of the baffle 102 is provided with a plurality of ventilation holes 107 .

[0052] A plurality of baffle side wall exhaust holes 105 are provided on the side wall of the annular ring 110 .

[0053] In one embodiment, the plurality of baffle side wall exhaust holes 105 are evenly distributed along the circumferential direction.

[0054] The spray plate 103 is located directly below the baffle plate 102. The spray plate 103 has a spray disc 111 and a side ring 112. The side ring 112 is arranged along the circumference of the spray disc 111. The upper surface of the side ring 112 is connected to the lower surface of the spray upper plate 101. The spray plate 103 and the baffle plate 102 form a second uniform gas mixing chamber.

[0055] The spray plate 111 of the spray plate 103 has a plurality of spray holes 108 .

[0056] The side wall of the side ring 112 has a plurality of shower plate side wall exhaust holes 106 .

[0057] In one embodiment, the plurality of shower plate side wall exhaust holes 106 are evenly distributed along the circumferential direction.

[0058] The radius of the side ring 112 of the shower plate 103 is greater than the radius of the annular ring 110 of the baffle 102. A first gap (combined with Figure 1 Reference), as part of the second homogenous gas mixing chamber.

[0059] In the prior art, the precursor entering from the spray plate is easily retained in the first gap, forming a dead zone, thereby affecting the efficiency of the precursor entering the spray plate. The concentration of the precursor in the dead zone will increase indefinitely, and the stability of the equipment cannot be guaranteed.

[0060] In the present invention, a baffle sidewall exhaust hole 105 is additionally provided on the side of the baffle to reduce the dead zone caused by gas trapped at the edge and improve the stability of the equipment.

[0061] In addition, since the radius of the side ring 112 of the shower plate 103 is smaller than the radius of the reaction chamber, a second gap (combined with the second gap) is formed between the side ring 112 of the shower plate and the side wall of the reaction chamber. Figure 1 Reference), the gas output from the shower plate 103 is easily retained in the gap, making the gap also a dead zone, resulting in uneven distribution of gas concentration, which further easily causes the edge of the deposited film to thicken, thereby deteriorating the uniformity within the film. In addition, when the shower plate is passed with purge gas, the existence of the dead zone will cause uneven distribution of the purge gas, resulting in uneven cleaning in the cavity, which is prone to local particle risks.

[0062] In the present invention, a spray plate side wall exhaust hole 106 is added to the side of the spray plate to reduce the dead zone caused by gas retention at the edge, improve the uniformity within the sheet and the stability of the equipment; at the same time, it can improve the cleaning efficiency and improve the performance of cavity particles.

[0063] Figure 3 A schematic diagram showing the gas flow direction of a uniform gas mixing structure according to an embodiment of the present invention is shown.

[0064] like Figure 3 As shown by the arrows, the gas enters the first homogenizing and mixing chamber from the air inlet 104 of the spray upper plate 101 for homogenizing and mixing, and then is output downward from the multiple vents 107 of the horizontal plate 109 of the baffle 102 to the second homogenizing and mixing chamber. At the same time, the gas can also be discharged from the multiple baffle side wall exhaust holes 105 ( Figure 3 A circle of exhaust holes 105 on the baffle side wall are framed and output to the side (i.e. radially) to the first gap of the second homogenous gas mixing chamber.

[0065] Figure 4A The process repeatability of the traditional gas homogenization structure is shown. Figure 4B The figure shows the process repeatability of the uniform gas mixing structure according to an embodiment of the present invention. The horizontal axis represents the data sequence number, and the vertical axis represents the normalized process film thickness. Figure 4A and Figure 4B It can be seen from the comparison that the uniform gas mixing structure of the present invention improves the uniformity within the chip and the stability of the equipment, and improves the process repeatability.

[0066] Figure 5 A schematic diagram showing the gas flow direction of a uniform gas mixing structure according to an embodiment of the present invention is shown.

[0067] like Figure 5 As shown, after the gas enters the second uniform gas mixing chamber from the multiple vent holes 107 of the horizontal plate 109 of the baffle plate 102 and the multiple baffle side wall exhaust holes 105, it is output downward to the reaction chamber from the spray hole 108 of the spray plate 103. At the same time, the gas can also be discharged from the spray plate side wall exhaust holes 106 ( Figure 5 A circle of exhaust holes 106 on the baffle side wall are framed and output to the side (ie radially) to the second gap of the reaction chamber.

[0068] Figure 6 The experimental effect diagram of the uniform gas mixing structure according to an embodiment of the present invention is shown, wherein the film thickness distribution, unevenness, range before and after the improvement are respectively shown. Data such as particle distribution and particle count.

[0069] In addition, it has been found through research that the uniform gas mixing structure of the present invention allows the coupling of airflow and plasma to be released by changing the flow resistance ratio of the baffle plate and the spray plate.

[0070] For example, when the ratio of the flow resistance of the baffle to the flow resistance of the shower plate is within a certain range, the gas is mainly concentrated in the baffle space (the first uniform gas mixing chamber) to form a congested flow, and the opening morphology of the baffle will affect the pattern of the film more. At this time, the shower plate is only used to diffuse the gas and affect the distribution of the RF plasma, and its opening morphology is unlikely to affect the pattern of the film. That is, the influence of the shower plate as the upper electrode on the distribution of the gas is weakened at this time. At this time, the pattern of the process film thickness is mainly controlled by the baffle, and the process performance can be improved by changing the hole distribution of the baffle, which greatly reduces the cost and processing cycle of hardware improvement. At the same time, the airflow and plasma are decoupled, making it easier to analyze whether the process performance is affected by the airflow or the plasma distribution.

[0071] According to the actual process performance, the recommended flow resistance ratio of the baffle and the spray plate is in the range of 5:1 to 15:1. This can not only realize the pattern of controlling the film thickness with the baffle and decoupling the airflow and plasma, but also prevent the gas from being trapped between the baffle and the spray upper plate due to excessive flow resistance, causing excessive local pressure.

[0072] In one embodiment, the flow resistance of the baffle plate or shower plate is changed by changing the diameter / depth / number of the vent holes in the direction facing the vacuum chamber.

[0073] Figure 7 The choking flow range and plasma distribution range of the uniform gas mixing structure according to an embodiment of the present invention are shown, wherein the flow resistance ratio of the baffle plate to the shower plate is less than 5:1.

[0074] Figure 8 The choking flow distribution range and the plasma distribution range of the uniform gas mixing structure according to an embodiment of the present invention are shown, wherein the flow resistance ratio of the baffle plate to the shower plate is in the range of 5:1 to 15:1.

[0075] Fig. 9 A schematic diagram showing the relationship between film thickness (THK) and refractive index (RI) according to an embodiment of the present invention is shown, wherein the flow resistance ratio of the baffle plate to the shower plate is less than 5:1.

[0076] Fig.10 A schematic diagram showing the relationship between film thickness (THK) and refractive index (RI) according to an embodiment of the present invention is shown, wherein the flow resistance ratio of the baffle plate to the shower plate is in the range of 5:1 to 15:1.

[0077] Compare Figure 7 and Figure 8 as well as Fig. 9 and Fig.10 It is found that when the flow resistance ratio of the baffle plate to the shower plate is different, the coupling degree between the congested flow 501 (601) and the plasma 502 (602) is different.

[0078] When the flow resistance ratio of the baffle plate to the spray plate is less than 5:1, Figure 7 As shown, the baffle and the shower plate both play a considerable role in gas uniformity, so the congested flow distribution range 501 and the plasma distribution range 502 are very close and are easily coupled together.

[0079] When the flow resistance ratio of the baffle plate to the spray plate is in the range of 5:1 to 15:1, Figure 8 As shown, the gas uniformity efficiency of the baffle is greatly enhanced, the congested flow 601 is basically concentrated on the baffle, and the gas uniformity effect of the shower plate is almost non-existent. The shower plate only acts as an upper electrode and gas diffusion, so that the coupling between the airflow (congested flow 601) and the plasma 602 is released. In this way, when it is necessary to improve the design of the shower plate hole, since the coupling between the airflow and the plasma is released, the analysis problem can be realized by single variable analysis, which greatly reduces the difficulty of solving the problem.

[0080] In the present disclosure, "gas" may include materials that are gases, vaporized solids, and / or vaporized liquids at normal temperature and pressure, and may consist of a single gas or a mixture of gases, depending on the context. A "gas" may be a process gas or a reactive gas, and may be a rare or otherwise inert gas. The term inert gas refers to a gas that does not participate in a chemical reaction to any appreciable extent and / or a gas that can excite a precursor when plasma power is applied. The terms precursor and reactant may be used interchangeably.

[0081] The terms and expressions used above are for descriptive purposes only, and the present invention should not be limited to these terms and expressions. The use of these terms and expressions does not mean to exclude any equivalent features of the illustrations and descriptions (or parts thereof), and it should be recognized that various modifications that may exist should also be included in the scope of the claims. Other modifications, changes and substitutions may also exist. Accordingly, the claims should be deemed to cover all such equivalents.

[0082] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus facilitate the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of this application, multiple features are sometimes combined into one embodiment, drawing or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims.

[0083] Similarly, it should be pointed out that although the present invention has been described with reference to the current specific embodiments, ordinary technicians in this technical field should realize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions may be made without departing from the spirit of the present invention. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present invention, they will fall within the scope of the claims of this application.

Claims

1. A uniform gas mixing structure, characterized in that: include: The spray upper plate, baffle plate and spray plate are arranged in sequence from top to bottom; The baffle plate comprises a horizontal plate and an annular ring, the annular ring is arranged along the circumference of the horizontal plate, the upper surface of the annular ring is connected to the lower surface of the spray upper plate, and the spray upper plate and the baffle plate form a first uniform gas mixing chamber; the horizontal plate is provided with a plurality of vent holes; the side wall of the annular ring is provided with a plurality of baffle side wall exhaust holes; The spray plate and the baffle plate form a second uniform gas mixing chamber.

2. The homogenous gas mixing structure according to claim 1, characterized in that: The spray plate comprises a spray disk and a side ring; the side ring is arranged along the circumference of the spray disk; the upper surface of the side ring is connected to the lower surface of the spray upper plate; the spray plate also comprises an upper electrode for forming radio frequency plasma.

3. The homogenous gas mixing structure according to claim 2, characterized in that: The spray plate is provided with a plurality of spray holes; the side wall of the side ring is provided with a plurality of spray plate side wall exhaust holes; the radius of the side ring is greater than the radius of the annular ring; a first gap is formed between the side ring and the annular ring as part of the second uniform gas mixing chamber; a second gap is formed between the side ring and the side wall of the reaction chamber as part of the reaction chamber.

4. The homogenous gas mixing structure according to claim 1, characterized in that: The plurality of exhaust holes on the baffle side walls are evenly distributed along the circumferential direction.

5. The homogenous gas mixing structure according to claim 1, characterized in that: The plurality of exhaust holes on the side wall of the spray plate are evenly distributed along the circumferential direction.

6. The homogenous gas mixing structure according to claim 1, characterized in that: The spray upper plate has an air inlet, which is located at the center of the spray upper plate, and gas enters the first uniform gas mixing chamber from the air inlet.

7. The homogenous gas mixing structure according to claim 6, characterized in that: After the gas enters the first uniform gas mixing chamber from the air inlet of the spray upper plate for uniform gas mixing, it is output downward from the multiple air vents of the horizontal plate to the second uniform gas mixing chamber. At the same time, the gas is also radially output from the multiple baffle side wall exhaust holes of the annular ring to the first gap of the second uniform gas mixing chamber.

8. The uniform gas mixing structure according to claim 6, characterized in that: After the gas enters the second uniform gas mixing chamber from the multiple air holes of the horizontal plate and the multiple exhaust holes on the baffle side wall, it is output downward from the spray hole to the reaction chamber. At the same time, the gas is also radially output from the exhaust holes on the side wall of the spray plate to the second gap in the reaction chamber.

9. The homogenous gas mixing structure according to claim 6, characterized in that: The ratio of the flow resistance of the baffle plate to the flow resistance of the shower plate is maintained within a range, so that the coupling between the congested flow formed by the gas and the radio frequency plasma is released.

10. The homogenous gas mixing structure according to claim 6, characterized in that: The range is 5:1 to 15:1.

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