Gas mixing structure and thin film deposition equipment

Abstract

The invention provides a gas mixing structure and thin film deposition equipment. The gas mixing structure comprises a gas mixing cavity provided with a gas outlet; the at least one gas inlet tank is arranged in the gas mixing cavity and comprises a plurality of mutually independent buffer cavities, and each buffer cavity is provided with a corresponding one-way opening; the first end of each gas inlet pipeline is connected with at least one gas source, and the second end of each gas inlet pipeline penetrates through the outer wall of the gas mixing cavity so as to extend into the corresponding buffer cavity and input gas into the corresponding buffer cavity, so that gas is supplied to the gas mixing cavity through the corresponding one-way opening.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor manufacturing, and in particular to a gas mixing structure and a thin film deposition device. BACKGROUND

[0002] In the process of semiconductor chip manufacturing, thin film deposition is the core process for preparing interlayer dielectric, pre-metal dielectric, metal interconnection layer and other key structures, and the quality of the thin film directly determines the core performance, structural reliability and long-term stability of the chip. With the advancement of chip manufacturing process to more advanced nodes of 3nm and below, the demand for high precision and high integration of chip manufacturing process continues to upgrade, which means that higher standards are required for the precision of thin film deposition and the stability of the process. In the traditional thin film deposition process, multiple reaction gases and carrier gases are usually introduced into the chamber at the same time. However, due to the differences in mass, viscosity and diffusion coefficient of different gas molecules, this approach can easily cause gas stratification, making it difficult to achieve uniform mixing, and thus causing poor uniformity of thin film thickness and deviation of chemical composition ratio from the target value. In addition, the differences in flow rate and viscosity of different gases can also cause instantaneous fluctuations in the pressure in the chamber when multiple gases are introduced into the chamber, affecting process repeatability and product consistency. Therefore, advanced chip manufacturing processes consider pre-mixing of various gases before they are introduced into the process chamber to improve production efficiency and product yield of chip manufacturing.

[0003] In the prior art, the gas is usually introduced into the process chamber first, and then guided into the gas mixing structure with the gas mixing function. After the various gases are mixed uniformly in the structure, they are introduced into the process chamber. However, the commonly used gas mixing structure is bidirectional, which cannot avoid the backflow of multiple gases in the structure into the gas inlet pipeline of other gases during the mixing process, thereby causing pipeline contamination. In addition, after various gases are output from the gas source, they are directly introduced into the gas mixing structure along the gas inlet pipeline, and the large initial momentum carried by them can easily destroy the stability of the flow field inside the gas mixing structure, thereby causing uneven mixing of various gases.

[0004] In order to overcome the above-mentioned defects in the prior art, there is an urgent need in the art for a gas mixing structure and a thin film deposition device that can solve the problem of gas cross-contamination in the gas mixing structure, eliminate the influence of the initial momentum carried by the gas on the mixing process, and thus balance the anti-pollution reliability and the uniformity of the mixing process to improve the product yield of the semiconductor chip manufacturing process. SUMMARY

[0005] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0006] To overcome the above-mentioned defects existing in the prior art, the present application provides a gas mixing structure and a thin film deposition device. By arranging multiple independent buffer chambers respectively connected with multiple gas sources inside the gas mixing structure, and adjusting the gas outlet structure of the buffer chambers as one-way openings, the influence of the initial momentum carried by the gas on the gas mixing process is eliminated while solving the problem of cross contamination of the gas inside the gas mixing structure, thereby improving the product yield of the semiconductor chip manufacturing process by taking into account the reliability of contamination prevention and the uniformity of gas mixing.

[0007] Specifically, the gas mixing structure according to the first aspect of the present application comprises: a gas mixing chamber provided with a gas outlet; at least one gas inlet tank arranged in the gas mixing chamber and comprising multiple independent buffer chambers, wherein each buffer chamber has a corresponding one-way opening; and multiple gas inlet pipelines, wherein the first end of each gas inlet pipeline is respectively connected with at least one gas source, and the second end thereof penetrates through the outer wall of the gas mixing chamber to extend into the corresponding buffer chamber and input gas into the corresponding buffer chamber to supply gas to the gas mixing chamber through the corresponding one-way opening.

[0008] Further, in some embodiments of the present application, the one-way opening is provided with a normally closed shutter rotating outwardly, wherein the normally closed shutter rotates outwardly when the gas pressure inside the buffer chamber is greater than the gas pressure outside the buffer chamber to open the one-way opening, and rotates back when the gas pressure inside the buffer chamber is less than or equal to the gas pressure outside the buffer chamber to close the one-way opening.

[0009] Further, in some embodiments of the present application, the one-way opening is arranged upwardly, and the normally closed shutter rotates upwardly against its own gravity when the gas pressure inside the buffer chamber is greater than the gas pressure outside the buffer chamber, and rotates back downwardly under the action of its own gravity when the gas pressure inside the buffer chamber is less than or equal to the gas pressure outside the buffer chamber.

[0010] Further, in some embodiments of the present application, the gas outlet is arranged at the bottom of the gas mixing chamber, and / or the front end of the gas outlet is provided with at least one narrowing structure.

[0011] Further, in some embodiments of the present application, the air inlet tank is divided into two independent buffer chambers, a rotating shaft is arranged on the partition between the two buffer chambers, and the two normally closed flaps share the rotating shaft to realize one-way rotation to the left and right sides.

[0012] Further, in some embodiments of the present application, a sealing mechanism is arranged at the position where the normally closed flap contacts the one-way opening.

[0013] Further, in some embodiments of the present application, a positioning pin is arranged on the outer wall of the air inlet tank, and a positioning hole is arranged at the corresponding position of the inner wall of the gas mixing chamber, and the air inlet tank is installed in the gas mixing chamber through the positioning pin and the positioning hole.

[0014] Further, in some embodiments of the present application, the gas mixing structure is arranged at the air inlet end of the process chamber of a thin film deposition device, wherein the first end of one of the air inlet pipelines is connected to a precursor source of a thin film deposition process, and the first end of the other air inlet pipeline is connected to a reaction gas source of the thin film deposition process.

[0015] Further, in some embodiments of the present application, an air inlet is further arranged on the gas mixing chamber, wherein the air inlet is connected to a dilution gas source.

[0016] In addition, the above-mentioned thin film deposition device according to the second aspect of the present application comprises: a process chamber, the air inlet end of which is provided with any of the gas mixing structures provided by the first aspect of the present application; a precursor source connected to the first air inlet pipeline of the gas mixing structure; and a reaction gas source connected to the second air inlet pipeline of the gas mixing structure. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above features and advantages of the present application can be better understood by reading the detailed description of embodiments of the present application in conjunction with the following drawings, in which: the components are not necessarily drawn to scale, and components having similar or related properties or features can have the same or similar reference numbers.

[0018] Figure 1 The overall structure of the gas mixing structure according to some embodiments of the present application is shown.

[0019] Figure 2 The structure of the air inlet tank according to some embodiments of the present application is shown.

[0020] Figure 3 The structure of the narrowing structure and the air outlet according to some embodiments of the present application is shown.

[0021] Figure 4 The top view of the air inlet tank according to some embodiments of the present application is shown.

[0022] Figure 5 A gas mixing flow chart of the gas mixing structure according to some embodiments of the present application is shown.

[0023] Reference signs:

[0024] Gas mixing structure 10

[0025] Air inlet tank 11

[0026] Air inlet pipeline 12

[0027] Buffer cavity 13

[0028] Normally closed shutter 14

[0029] Partition 15

[0030] Rotary shaft 16

[0031] Positioning pin 17

[0032] Air outlet 20

[0033] Narrowing structure 21 DETAILED DESCRIPTION

[0034] The present application is described herein with reference to particular embodiments for a purpose of illustration only. The present application is not limited to the embodiments described herein, but rather the scope of the present application is defined by the appended claims. Various further aspects and advantages of the present application will become apparent from the following description, when considered in conjunction with the accompanying drawings. It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not intended to be restrictive of the present application, as claimed.

[0035] In the description of the present application, it is to be understood that the specific terms of "mounting", "connected", "connecting" should be construed broadly according to the content amenable to the present application, unless otherwise specifically defined and limited. For example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium; it can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] In addition, "upper", "lower", "left", "right", "top", "bottom", "horizontal", "vertical" used in the following description and shown in the drawings should be understood as the orientation shown in the drawing and relative to the article being described. These relative terms are used only to facilitate the description of the application and are not intended to limit the application to a particular orientation of the article being described, and should not be construed as limiting the application.

[0037] It is to be understood that the terms "first", "second", "third", and so on, used herein to describe various components, regions, layers and / or sections, should not be construed as limiting those components, regions, layers and / or sections, and the terms are only used to distinguish different components, regions, layers and / or sections. Therefore, the first components, regions, layers and / or sections discussed below can be referred to as the second components, regions, layers and / or sections without departing from some embodiments of the application.

[0038] In the prior art, the gas is usually guided into the gas inlet structure with a gas mixing function before being introduced into the process chamber. After the various gases are mixed uniformly in the structure, they are introduced into the process chamber. However, the commonly used gas mixing structure is bidirectional, which cannot avoid the backflow of various gases in the structure during the gas mixing process, thereby causing pipeline pollution. In addition, after various gases are output from the gas source, they are directly introduced into the gas mixing structure along the gas inlet pipe path, and the large initial momentum carried by the gases easily destroys the stability of the flow field inside the gas mixing structure, thereby causing uneven mixing of various gases.

[0039] In order to overcome the above-mentioned defects in the prior art, the present application provides a gas mixing structure and a thin film deposition device. By arranging a plurality of independent buffer cavities respectively connected to a plurality of gas sources in the gas mixing structure, and adjusting the gas outlet structure of the buffer cavities to be a one-way opening, the gas mixing structure can solve the problem of cross contamination of gases inside the gas mixing structure, eliminate the influence of the initial momentum carried by the gases on the gas mixing process, and thus improve the product yield of semiconductor chip manufacturing process by taking into account the reliability of pollution prevention and the uniformity of gas mixing.

[0040] In some non-limiting embodiments, the above-mentioned gas mixing structure provided by the first aspect of the present application can be installed in the above-mentioned thin film deposition device provided by the second aspect of the present application.

[0041] Please refer to Figures 1-5 .

[0042] Figure 1 The overall structure of the gas mixing structure provided by some embodiments of the present application is shown.

[0043] Figure 2 The structure of the gas inlet tank provided by some embodiments of the present application is shown.

[0044] Figure 3 A schematic diagram of the narrowing structure and air outlet provided according to some embodiments of the present invention is shown.

[0045] Figure 4 A top view of the air intake tank provided according to some embodiments of the present invention is shown.

[0046] Figure 5 A gas mixing flow diagram of a gas mixing structure provided according to some embodiments of the present invention is shown.

[0047] like Figure 1 and Figure 2 As shown, the mixing structure 10 provided by the first aspect of the present invention includes a mixing chamber, at least one air inlet tank 11, and multiple air inlet pipes 12.

[0048] In some embodiments, the mixing chamber is provided with an air outlet 20.

[0049] In some embodiments, at least one air inlet 11 is disposed in the mixing chamber and includes a plurality of independent buffer chambers 13.

[0050] Specifically, in some embodiments, at least one air inlet 11 is disposed in the mixing chamber, and each air inlet 11 is divided into multiple independent buffer chambers 13.

[0051] Optionally, in some embodiments, a plurality of air intake cans 11 are disposed in the mixing chamber, and each air intake can 11 includes at least one buffer chamber 13.

[0052] Furthermore, in some embodiments, each buffer cavity 13 has a corresponding one-way opening.

[0053] In some instances, the first end of each intake pipe 12 is connected to at least one air source, while its second end passes through the outer wall of the mixing chamber to extend into the corresponding buffer chamber 13 and inputs gas into the corresponding buffer chamber 13 to supply gas to the mixing chamber via the corresponding one-way opening.

[0054] Thus, this invention solves the problem of cross-contamination of gases inside the gas mixing structure 10 by setting multiple independent buffer chambers 13, each connected to multiple gas sources, and adjusting the outlet structure of the buffer chambers 13 to a unidirectional opening structure. This improves the backflow phenomenon of gases inside the gas mixing structure 10 to other inlet pipes 12. Furthermore, the independent buffer chambers 13 can also eliminate the negative impact of the initial lateral momentum carried by the input gas, thereby stabilizing the internal gas pressure of the mixing chamber and reducing its internal gas velocity. This facilitates thorough mixing of the input gas within the mixing chamber, thus balancing the anti-contamination reliability and gas mixing uniformity of the gas mixing structure 10, and improving the product yield of semiconductor chip manufacturing processes.

[0055] Furthermore, in some embodiments, a normally closed baffle 14 that rotates outward in one direction is provided on the one-way opening. The normally closed baffle 14 rotates outward to open the one-way opening when the air pressure inside the buffer cavity 13 is greater than the air pressure outside the buffer cavity 13, and rotates back to close the one-way opening when the air pressure inside the buffer cavity 13 is less than or equal to the air pressure outside the buffer cavity 13.

[0056] Furthermore, in some embodiments, the one-way opening is arranged facing upwards, and an elastic mechanism is provided on the normally closed baffle 14. When the air pressure inside the buffer cavity 13 is greater than the air pressure outside the buffer cavity 13, the normally closed baffle 14 rotates outwards against the elastic force of the elastic mechanism and its own weight. When the air pressure inside the buffer cavity 13 is less than or equal to the air pressure outside the buffer cavity 13, it rotates back under the action of the elastic force of the elastic mechanism and the action of its own weight.

[0057] Thus, by setting an adjustable elastic structure on the normally closed baffle 14, the present invention can not only achieve one-way ventilation of the air inlet tank 11, but also control the gas inside the buffer chamber 13 to output gas to the mixing chamber for gas mixing at different pressure nodes inside the chamber, so as to meet the pressure requirements of different process flows for the internal pressure of the buffer chamber 13 and expand the adjustment window of the semiconductor thin film deposition process.

[0058] Optionally, in some embodiments, the one-way opening is arranged upwards. When the air pressure inside the buffer chamber 13 is greater than the air pressure outside the buffer chamber 13, the normally closed baffle 14 rotates upwards against its own gravity, and when the air pressure inside the buffer chamber 13 is less than or equal to the air pressure outside the buffer chamber 13, it rotates downwards under its own gravity.

[0059] Thus, the present invention utilizes the gravity of the normally closed baffle 14 to achieve one-way ventilation of the air inlet tank 11, thereby reducing process costs, simplifying device structure, reducing additional pollution to the process chamber caused by aging and corrosion of elastic structure, and extending the service life of the device, thereby balancing the process cost and production reliability of semiconductor chip manufacturing.

[0060] Furthermore, in some embodiments, the air outlet 20 is located at the bottom of the mixing chamber.

[0061] Thus, by placing the gas outlet 20 at the bottom of the mixing chamber, which is far from the one-way opening of the buffer chamber 13, the present invention maximizes the mixing path of the various gases after they are output from the buffer chamber 13, thereby increasing the residence time of the various gases in the mixing chamber, and thus improving the mixing effect of the various gases and improving the product yield of semiconductor chip manufacturing.

[0062] Optionally, such as Figure 3 As shown, in some embodiments, the front end of the air outlet 20 is provided with at least one narrowing structure 21.

[0063] Thus, by setting a structure at the front end of the outlet 20 that first narrows, then maintains the same diameter, and finally diffuses, the present invention increases the flow resistance at the front end of the outlet 20, further increasing the residence time of multiple gases in the mixing chamber, thereby improving the mixing effect of multiple gases and increasing the product yield of semiconductor chip manufacturing.

[0064] Furthermore, in some embodiments, the air intake tank 11 is divided into two independent buffer chambers 13, and a rotating shaft 16 is provided on the partition 15 between the two buffer chambers 13. The two normally closed baffles 14 reuse the rotating shaft 16 to achieve outward unidirectional rotation to both sides.

[0065] Thus, by setting two independent buffer chambers 13 with normally closed baffles 14 sharing the same rotating shaft 16, the present invention simplifies the one-way opening structure while enabling the two normally closed baffles 14 to rotate outward in one direction to both sides. Furthermore, by enabling the two normally closed baffles 14 to rotate outward in one direction to both sides, multiple gases are prevented from contacting at the one-way opening position, thereby avoiding the reaction of multiple gases and the deposition of by-products, and thus improving the sealing performance and service life of the normally closed baffles 14.

[0066] Furthermore, in some embodiments, a sealing mechanism is provided at the position where the normally closed baffle 14 contacts the one-way opening.

[0067] Specifically, in some embodiments, the sealing mechanism is a sealing ring.

[0068] Furthermore, such as Figure 4 As shown, in some embodiments, the outer wall of the air inlet tank 11 is provided with a positioning pin 17, and the corresponding position of the inner wall of the mixing chamber is provided with a positioning hole (not shown in the figure). The air inlet tank 11 is installed in the mixing chamber via the positioning pin 17 and the positioning hole.

[0069] Thus, by setting a positioning pin 17 on the outer wall of the air inlet tank 11 and a positioning hole matching the positioning pin 17 on the inner wall of the mixing chamber, the present invention can accurately position the air inlet tank 11 in the mixing chamber, thereby improving the ease of device assembly and maximizing the mixing effect of the mixing chamber for multiple gases.

[0070] Furthermore, the thin film deposition apparatus provided in the second aspect of the present invention includes a process chamber, a precursor source, and a reactive gas source.

[0071] In some embodiments, the air inlet of the process chamber is provided with any of the gas mixing structures 10 provided by the first aspect of the present invention.

[0072] In some embodiments, the precursor source is connected to the first intake pipe of the mixing structure 10.

[0073] In some embodiments, the reaction gas source is connected to the second air inlet pipe of the mixing structure 10.

[0074] Furthermore, in some embodiments, the gas mixing structure 10 is disposed at the air inlet end of the process chamber of the thin film deposition apparatus.

[0075] In some embodiments, the first end of an intake pipe is connected to a precursor source for a thin film deposition process.

[0076] Specifically, in some embodiments, the precursor source includes a TEOS source.

[0077] In some embodiments, the first end of another intake pipe is connected to the reaction gas source of the thin film deposition process.

[0078] Specifically, in some embodiments, the reaction gas source includes an O3 source.

[0079] Furthermore, in some embodiments, the mixing chamber is also provided with an air inlet, which is connected to a dilution gas source.

[0080] Specifically, in some embodiments, the dilution gas source includes an inert gas source.

[0081] Specifically, in some embodiments, the inert gas source includes an argon gas source.

[0082] Optionally, in some embodiments, the inert gas source includes a nitrogen source.

[0083] Optionally, in some embodiments, the inert gas source includes a helium source.

[0084] The working principle of the gas mixing structure 10 will be described below with reference to some embodiments of the gas mixing method of the gas mixing structure 10. Those skilled in the art will understand that these embodiments of the gas mixing method are merely non-limiting implementations provided by the present invention, intended to clearly demonstrate the technical concept of the present invention and provide some specific solutions convenient for public implementation, rather than limiting all working methods of the gas mixing structure 10. Similarly, the gas mixing structure 10 described above is also merely a non-limiting implementation of the present invention and does not limit the execution order or the objects of operation in the following gas mixing methods.

[0085] like Figure 5 As shown, gas mixing using the gas mixing structure 10 includes the following steps:

[0086] Step S01: During the thin film deposition process, a precursor source (e.g., a TEOS source) is first supplied to the gas mixing structure via the first gas inlet pipe.

[0087] Step S02: After the precursor is mixed with dilution gas and the pressure is adjusted in the mixing chamber, it is input into the process chamber for precursor deposition.

[0088] Step S03: The reaction gas source (e.g., O3 source) supplies the reaction gas to the mixing structure via the second gas inlet pipe.

[0089] Step S04: After the reaction gas is mixed with the dilution gas and the pressure is adjusted in the mixing chamber, it is introduced into the process chamber to react with the deposition precursor and form a thin film.

[0090] Optionally, in some embodiments, the first air intake pipe is connected to the precursor source, and the second air intake pipe is connected to the dilution gas source. The precursor source and the dilution gas source simultaneously supply gas to the air intake tank 11 through corresponding pipes to perform mixed gas pressure regulation of the precursor.

[0091] Optionally, in some embodiments, the first air inlet pipe is connected to the reactant source, and the second air inlet pipe is connected to the dilution gas source. The precursor source and the dilution gas source simultaneously supply gas to the air inlet tank 11 through the corresponding pipes to perform gas mixing and pressure regulation of the reactant gases.

[0092] Although the methods described above are illustrated and depicted as a series of actions for the sake of simplicity, it should be understood and appreciated that these methods are not limited by the order of the actions, as some actions may occur in a different order and / or concurrently with other actions from the illustrations and descriptions herein or not illustrated and described herein but which may be understood by those skilled in the art, according to one or more embodiments.

[0093] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A gas mixing structure, characterized by, The application relates to a gas mixing structure. The gas mixing structure comprises: a mixing cavity provided with a gas outlet; at least one gas inlet tank arranged in the mixing cavity and comprising a plurality of mutually independent buffer cavities, wherein each buffer cavity is respectively provided with a corresponding one-way opening; and 2. The gas mixing structure of claim 1, wherein a plurality of gas inlet pipelines, wherein the first ends of the gas inlet pipelines are respectively connected to at least one gas source, and the second ends of the gas inlet pipelines penetrate the outer wall of the mixing cavity to extend into the corresponding buffer cavities and input gas into the corresponding buffer cavities to supply gas to the mixing cavity through the corresponding one-way openings.

3. The gas mixing structure of claim 2, wherein The one-way opening is provided with a normally closed shutter which rotates outwardly in a one-way manner, wherein the normally closed shutter rotates outwardly when the air pressure in the buffer cavity is greater than the air pressure outside the buffer cavity to open the one-way opening, and the normally closed shutter rotates back when the air pressure in the buffer cavity is less than or equal to the air pressure outside the buffer cavity to close the one-way opening.

4. The gas mixing structure of claim 3, wherein The one-way opening is arranged upwardly, and the normally closed shutter rotates upwardly against its own gravity when the air pressure in the buffer cavity is greater than the air pressure outside the buffer cavity, and the normally closed shutter rotates downwardly under the action of its own gravity when the air pressure in the buffer cavity is less than or equal to the air pressure outside the buffer cavity. The gas outlet is arranged at the bottom of the mixing cavity, and / or 5. The gas mixing structure of claim 2, wherein The front end of the gas outlet is provided with at least one narrowing structure.

6. The gas mixing structure of claim 2, wherein The gas inlet tank is divided into two mutually independent buffer cavities, and a rotating shaft is arranged on the partition plate between the two buffer cavities, and the two normally closed shutters share the rotating shaft to realize outward one-way rotation to the two sides.

7. The gas mixing structure of claim 1, wherein The position where the normally closed shutter contacts the one-way opening is provided with a sealing mechanism.

8. The gas mixing structure of claim 1, wherein The outer wall of the gas inlet tank is provided with a positioning pin, and the corresponding position of the inner wall of the mixing cavity is provided with a positioning hole, and the gas inlet tank is installed in the mixing cavity through the positioning pin and the positioning hole.

9. The gas mixing structure of claim 8, wherein The gas mixing structure is arranged at the gas inlet end of a process cavity of a thin film deposition device, wherein the first end of one of the gas inlet pipelines is connected to a precursor source of a thin film deposition process, and the first end of another of the gas inlet pipelines is connected to a reaction gas source of the thin film deposition process.

10. A thin film deposition apparatus, characterized by, The mixing cavity is further provided with a gas inlet, wherein the gas inlet is connected to a dilution gas source. The application further relates to a thin film deposition device. The thin film deposition device comprises: a process cavity provided with the gas mixing structure as claimed in any one of claims 1 to 9 at the gas inlet end of the process cavity; a precursor source connected to the first gas inlet pipeline of the gas mixing structure; and a reaction gas source connected to the second gas inlet pipeline of the gas mixing structure.

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