Method for depositing high quality silicon nitride thin films and system therefor

Abstract

The present application relates to a method for depositing high-quality silicon nitride film, which uses hot-wire chemical vapor deposition technology, comprising: preheating the hot wire arranged in the process cavity with small current; heating the preheated hot wire with large current and introducing ammonia into the process cavity, controlling the pressure of the process cavity to react; keeping the hot wire heated with large current and introducing ammonia, introducing silane into the process cavity, controlling the pressure of the process cavity to react; continue to keep the hot wire heated with large current and continue to keep the ammonia, and the process cavity is not controlled pressure; the hot wire heated with large current is cooled to small current for heating buffer. In addition, the present application also relates to a HoFCVD system. The present application effectively solves the problem that silane is preferentially decomposed to ammonia, and improves the quality of silicon nitride film. The present application can also perfectly solve the problems of amorphous silicon film layer damage caused by too high temperature of the film-coated substrate of PECVD equipment and insufficient production capacity caused by slow film-coating rate of ALD equipment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor material preparation, and more particularly, relates to a method for depositing a high-quality silicon nitride film and a system thereof. BACKGROUND

[0002] Crystalline silicon solar cells are threatened by various corrosion factors during long-term outdoor operation. For example, moisture, oxygen, acidic or alkaline pollutants (such as sulfur dioxide, nitrogen oxides, sea salt particles, etc.) in the air can cause corrosion to the battery components. These corrosion factors can damage the electrodes, films and packaging materials of the battery, thereby reducing the photoelectric conversion efficiency and service life of the battery.

[0003] Silicon nitride has excellent chemical stability. It can remain stable in general acid-base environments and does not easily react with common acidic or alkaline substances. This property enables it to effectively block external corrosive media from contacting the key components of crystalline silicon solar cells. In addition, silicon nitride has good interface compatibility with crystalline silicon materials. In the structure of a solar cell, it can be closely attached to the surface of crystalline silicon and will not cause interface separation due to differences in thermal expansion coefficient, etc. This enables it to play a long-term stable anti-corrosion role and ensure the performance of crystalline silicon solar cells. In addition, the silicon nitride film not only has an anti-corrosion effect, but also can improve the photoelectric performance of the battery. It can act as an anti-reflective coating to reduce the reflection loss of light on the surface of the battery, thereby improving the light absorption efficiency of the battery and increasing the short-circuit current.

[0004] Currently, the main equipment for preparing silicon nitride is plasma enhanced chemical vapor deposition (PECVD), hot filament chemical vapor deposition (HoFCVD), and atomic layer deposition (ALD). The silicon nitride film prepared by chemical vapor deposition has a dense microstructure, with atoms closely arranged to form a physical barrier that can effectively prevent the penetration of small molecules such as moisture and oxygen. The prepared silicon nitride film has been widely applied to crystalline silicon solar cells as an anti-corrosion layer and an anti-reflective layer.

[0005] However, the PECVD equipment has a high film coating rate, but the surface of the cell piece is damaged by plasma, and the film coating temperature is usually 300-400 DEG C, which is limited in application field, for example, the temperature requirement of the crystalline silicon heterojunction cell process route is lower than 200 DEG C, otherwise the amorphous silicon layer will be damaged. The ALD equipment has good film uniformity and high film thickness control precision, but the deposition rate is slow, which is not suitable for large-scale deposition of thin film application, the production capacity is limited, and the equipment cost is high, the investment is large, and the cost performance is low. The HoFCVD equipment has low cost, fast thin film deposition rate, and the price is only half of the PECVD under the same production capacity, and the HoFCVD equipment has no plasma damage in the film coating process, which can reduce the surface defects caused by the thin film deposition process, in addition, the HoFCVD equipment can simultaneously compatible with high temperature deposition of silicon nitride, low temperature deposition of silicon nitride process, and has wide application field, therefore, the HoFCVD equipment becomes the first choice for depositing silicon nitride thin film.

[0006] However, the HoFCVD equipment utilizes the hot wire under large current, and the temperature rises sharply to 1800-2200 DEG C, and active groups are formed by high temperature catalytic cracking of reaction gas, but the hot wire will experience a process of rapid rising and reaching stable voltage after passing through large current, and in the voltage rising stage, the temperature of the hot wire is relatively low, and the decomposition temperature of silane (400 DEG C) is less than that of ammonia (800 DEG C), therefore, in this stage, silane will be preferentially decomposed and deposited on the substrate to form amorphous silicon thin film, which leads to poor quality of the prepared silicon nitride thin film, easy to be corroded by acid and alkali, and slightly poor light transmission performance.

[0007] Therefore, it is urgent to design a process capable of depositing and preparing high-quality silicon nitride thin film to solve the above problems. SUMMARY

[0008] In view of the deficiencies of the prior art, the purpose of the present application is to provide a method for preparing high-quality silicon nitride thin film by optimizing the formula process, so as to improve the light transmission, corrosion resistance and other properties of the silicon nitride thin film, and further improve the electrical properties and service life of the crystalline silicon cell piece.

[0009] In order to solve the above technical problems or achieve the above purpose, the present application adopts the following technical scheme:

[0010] According to one aspect of the present application, a method for depositing high-quality silicon nitride thin film is provided, using hot wire chemical vapor deposition technology, comprising:

[0011] S1: preheating the hot wire arranged in the process cavity by small current;

[0012] S2: heating the preheated hot wire by large current and introducing ammonia into the process cavity, and controlling the pressure of the process cavity to react;

[0013] S3: keeping the hot wire using large current heating and passing in ammonia, and passing in silane into the process cavity, and controlling the pressure of the process cavity to react;

[0014] S4: continuing to keep the hot wire using large current heating and continuing to keep passing in ammonia, and not controlling the pressure of the process cavity;

[0015] S5: reducing the hot wire using large current heating to use small current heating buffer.

[0016] In an embodiment of the present application, the method further comprises:

[0017] Based on the thickness of the required silicon nitride film, repeating steps S2-S4.

[0018] In an embodiment of the present application, in steps S1-S5, the range of small current is 6-8A, and the range of large current is 30-36A.

[0019] In an embodiment of the present application, in step S1, the preheating time of the hot wire is 5-6s, in step S2, the reaction time of passing in ammonia is 5-6s, in step S3, the reaction time of passing in silane is 6-8s, in step S4, the time of continuing to keep passing in ammonia is 3-4s, and in step S5, the heating buffer time is 10-12s.

[0020] In an embodiment of the present application, in steps S2-S4, the flow rate of passing in ammonia is 5000-5500sccm, and the flow rate of passing in silane is 500-550sccm.

[0021] In an embodiment of the present application, in steps S2 and S3, the pressure of the process cavity is controlled at 1-1.5Pa.

[0022] In an embodiment of the present application, the diameter of the hot wire is 0.7mm.

[0023] According to another aspect of the present application, a system for depositing high-quality silicon nitride film using the method of depositing high-quality silicon nitride film as described above is provided, which is a hot wire chemical vapor deposition system, comprising:

[0024] A main machine table, comprising a feeding cavity, a heating cavity, a uniform heating cavity, a process cavity and a discharging cavity which are sequentially communicated with each other;

[0025] The automation equipment comprises a large gantry and a turnover machine on one side of the feeding cavity, a large gantry and a turnover machine on one side of the discharging cavity, and a carrier plate backflow rack below the main machine table, wherein each large gantry is configured to grab the silicon wafer to complete the feeding and discharging of the silicon wafer, each turnover machine is configured to turn the carrier plate from a vertical state to a horizontal state to facilitate the feeding and discharging of the large gantry, and the carrier plate backflow rack is configured to realize the recycling of the carrier plate after the carrier plate is discharged from the discharging station and turned to the feeding station.

[0026] The automation equipment comprises a large gantry and a turnover machine on one side of the feeding cavity, a large gantry and a turnover machine on one side of the discharging cavity, and a carrier plate backflow rack below the main machine table, wherein each large gantry is configured to grab the silicon wafer to complete the feeding and discharging of the silicon wafer, each turnover machine is configured to turn the carrier plate from a vertical state to a horizontal state to facilitate the feeding and discharging of the large gantry, and the carrier plate backflow rack is configured to realize the recycling of the carrier plate after the carrier plate is discharged from the discharging station and turned to the feeding station.

[0027] In an embodiment of the present application, the heating cavity is heated by high power to rapidly heat the carrier plate to 110 DEG C, and the uniform heating cavity is heated by low power to control the temperature uniformity of the carrier plate within ± 5 DEG C.

[0028] In an embodiment of the present application, the system is a 700 MW capacity hot filament chemical vapor deposition system, and the hot filament chemical vapor deposition system adopts a double-carrier plate vertical coating process, each carrier plate places 216 silicon wafers, and the single process cavity cycle is 96s.

[0029] Compared with the prior art, the technical scheme provided by the present application has the following advantages:

[0030] The present application effectively solves the problem of decomposition of silane in preference to ammonia by precisely controlling the current and / or gas flow in multiple steps and stages of the hot filament CVD (HoFCVD) process, and improves the quality of the silicon nitride film.

[0031] The HoFCVD system for depositing the silicon nitride film in the present application can match a 700 MW capacity crystalline silicon heterojunction scheme, and perfectly solve the problems of damage to amorphous silicon film layer caused by excessively high substrate temperature in PECVD equipment and insufficient production capacity caused by slow coating rate in ALD equipment. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.

[0033] In order to more clearly illustrate the technical schemes in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced as follows, and obviously, other accompanying drawings can also be obtained by those skilled in the art without any creative effort on the basis of these accompanying drawings.

[0034] Figure 1A flowchart of a method for depositing high-quality silicon nitride film is shown.

[0035] Figure 2 A brief structural schematic diagram of a HoFCVD system for high-quality silicon nitride film deposition is shown. Figure 1

[0036] Figure 3 A schematic diagram of a mass production line carrier plate temperature measurement point of a HoFCVD system is shown. Figure 2

[0037] Figure 4 A schematic diagram of a measured carrier plate heating curve based on a mass production line carrier plate temperature measurement point of a HoFCVD system is shown. Figure 3

[0038] 1, main machine table; 2, feeding cavity; 3, heating cavity; 4, uniform heating cavity; 5, first process cavity; 6, second process cavity; 7, discharging cavity; 8, automation equipment; 9, large gantry; 10, turnover machine; 11, carrier plate backflow frame; 12, buffer bin. DETAILED DESCRIPTION

[0039] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the embodiments of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0040] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some of the embodiments of the present application, not all the embodiments.

[0041] As shown in Figure 1 The embodiments of the present application provide a method for depositing high-quality silicon nitride film, which uses hot wire chemical vapor deposition technology and includes the following steps:

[0042] S1: preheat the hot wire arranged in the process cavity with a small current;

[0043] S2: heat the preheated hot wire with a large current and introduce ammonia into the process cavity, and control the pressure of the process cavity to react;

[0044] S3: continue to heat the hot wire with a large current and continue to introduce ammonia, and introduce silane into the process cavity, and control the pressure of the process cavity to react;

[0045] S4: continue to heat the hot wire with a large current and continue to introduce ammonia, and do not control the pressure of the process cavity; ​​​

[0046] S5: cooling the hot filament heated by the large current to heating buffering by the small current.

[0047] The method of the present application effectively solves the problem of decomposition of silane in preference to ammonia, and improves the quality of the silicon nitride film, by precise control of the multi-step, phased current and / or gas flow of the hot filament CVD (HoFCVD) process.

[0048] In the above embodiment of the present application, preferably, the method further comprises: repeating steps S2-S4 based on the thickness of the required silicon nitride film. According to the target thickness of the required silicon nitride film, the operation of the above steps S2-S4 is repeated, and such repeated process can precisely control the thickness of the film to reach the required target thickness.

[0049] In the above embodiment of the present application, in steps S1-S5, the small current is in the range of 6-8A, preferably 6A; and the large current is in the range of 30-36A, preferably 30A.

[0050] In the above embodiment of the present application, in step S1, the preheating time of the hot filament is 5-6s, preferably 5s; in step S2, the ammonia gas reaction time is 5-6s, preferably 5s; in step S3, the silane gas reaction time is 6-8s, preferably 6s; in step S4, the ammonia gas continues to be supplied for 3-4s, preferably 3s; and in step S5, the heating buffering time is 10-12s, preferably 10s.

[0051] In the above embodiment of the present application, in steps S2-S4, the flow rate of the ammonia gas supplied is 5000-5500sccm, preferably 5000sccm; and the flow rate of the silane gas supplied is 500-550sccm, preferably 500sccm.

[0052] In the above embodiment of the present application, in steps S2 and S3, the pressure in the process chamber is controlled to be in the range of 1-1.5Pa, preferably 1Pa.

[0053] In the above embodiment of the present application, the diameter of the hot filament is 0.7mm.

[0054] As shown in Figure 2 The embodiment of the present application also provides a system for depositing high-quality silicon nitride film by the method for depositing high-quality silicon nitride film as shown in Figure 1 The system is a hot filament chemical vapor deposition system, which comprises:

[0055] A main machine table 1, which comprises a feeding chamber 2, a heating chamber 3, a uniform heating chamber 4, process chambers (a first process chamber 5 and a second process chamber 6), and a discharging chamber 7, which are sequentially and mutually connected;

[0056] The automation device 8 includes a large gantry 9 and a turnover machine 10 located on one side of the feeding cavity 2, a large gantry 9 and a turnover machine 10 located on one side of the discharging cavity 7, and a carrier plate backflow rack 11 located below the main machine table 1, wherein each large gantry 9 is configured to grab the silicon wafer to complete the feeding and discharging of the silicon wafer, each turnover machine 10 is configured to turn the carrier plate from a vertical state to a horizontal state to facilitate the feeding and discharging of the large gantry 9, and the carrier plate backflow rack 11 is configured to turn the carrier plate from the unloading station to the loading station after unloading to realize the recycling of the carrier plate.

[0057] Two buffer warehouses 12 are located at both ends of the carrier plate backflow rack 11 and adjacent to the corresponding turnover machines 10, and the buffer warehouse 12 is configured to realize the transition of the carrier plate from the carrier plate backflow rack 11 to the turnover machine 10 and from the turnover machine 10 to the main machine table 1.

[0058] The HoFCVD system for depositing silicon nitride film in the application can match a 700MW capacity of a crystalline silicon heterojunction scheme, and can perfectly solve the problems of amorphous silicon film layer damage caused by too high substrate temperature of a PECVD device and insufficient production capacity caused by slow film deposition rate of an ALD device.

[0059] In the above embodiment of the application, the heating cavity 3 is heated by high power to rapidly heat the carrier plate to 110℃, and the uniform heating cavity 4 is heated by low power to control the temperature uniformity of the carrier plate within ±5℃.

[0060] In the above embodiment of the application, the system is a 700MW capacity hot filament chemical vapor deposition system, and the hot filament chemical vapor deposition system adopts double carrier plate vertical film deposition, each carrier plate places 216 silicon wafers, and the single process cavity cycle is 96s.

[0061] The above technical solutions of the application will be described in detail through specific embodiments.

[0062] In order to solve the problem of amorphous silicon film deposition caused by the decomposition of silane in preference to ammonia during the heating process of the hot filament, the process formula is optimized as follows: a method for depositing high-quality silicon nitride film, which uses hot filament chemical vapor deposition technology, and the specific steps are as follows.

[0063] First step: the hot filament arranged in the process cavity is preheated by a small current of 6-8A, and the process time is 5-6s.

[0064] This step aims to initially preheat the hot filament to make it enter a relatively stable initial state and prepare for the subsequent deposition process.

[0065] Second step: increase the current of the hot wire to a large current of 30-36A for heating, and at the same time, introduce ammonia into the process cavity, set the flow rate of the ammonia to 5000-5500sccm, and control the pressure of the process cavity to 1-1.5Pa for reaction for 5-6s.

[0066] In this step, the hot wire is rapidly heated by a large current, and a large amount of ammonia is introduced to decompose the ammonia near the hot wire and form a high-concentration atmosphere, creating favorable conditions for subsequent synergistic reaction with silane.

[0067] Third step: keep the hot wire heated by a large current of 30-36A and keep introducing ammonia, set the flow rate of the ammonia to 5000-5500sccm, and at the same time, introduce silane into the process cavity, set the flow rate of the silane to 500-550sccm, and control the pressure of the process cavity to 1-1.5Pa for reaction for 6-8s.

[0068] In this step, by controlling the flow rates of ammonia and silane, the two gases are decomposed and reacted in an orderly manner around the hot wire. In this stage, silane and ammonia begin to chemically react under the high-temperature catalytic cracking of the hot wire, and thin films are deposited on the substrate. Since the hot wire has been raised to the target temperature in advance, the situation that silane is preferentially decomposed over ammonia at low temperature of the hot wire is avoided, and there is a sufficient amount of high-concentration active nitrogen atoms in the process cavity, which helps to form high-quality silicon nitride films.

[0069] Fourth step: continue to keep the hot wire heated by a large current of 30-36A and continue to introduce ammonia, set the flow rate of the ammonia to 5000-5500sccm, and do not control the pressure of the process cavity for reaction for 3-4s.

[0070] This step further ensures the dominant position of active nitrogen atoms in the reaction process and avoids the deposition of amorphous silicon films caused by gas evacuation.

[0071] Fifth step: reduce the hot wire heated by a large current of 30-36A to a small current of 6-8A for heating for 10-12s.

[0072] This step serves as a buffer stage to avoid excessive elongation of the hot wire caused by long-term large-current work and catalysis, which affects the service life, and also reduces the substrate temperature to avoid damage to the high-temperature film layer caused by excessive radiation from the hot wire.

[0073] In addition, the above method further comprises: repeating the operations of the second step to the fourth step according to the target thickness of the silicon nitride film required. Through this repeated process, the thickness of the film can be accurately controlled to reach the target thickness required.

[0074] In addition, referring again to Figure 2The present application uses a HoFCVD system to prepare a silicon nitride film, the HoFCVD system comprising a main machine 1 and an automatic device 8.

[0075] The main machine 1 comprises a feeding cavity 2, a heating cavity 3, a uniform heating cavity 4, a first process cavity 5, a second process cavity 6 and a discharging cavity 7. The feeding cavity 2 and the discharging cavity 7 are responsible for completing the transition from vacuum to atmosphere. Two-stage heating is adopted in the present application to ensure temperature uniformity: the heating cavity 3 is heated by high power to quickly heat the carrier plate to 110℃, and the uniform heating cavity 4 is heated by small power to make the temperature of the higher area of the carrier plate decrease faster than the lower area, so as to achieve the goal of uniform heating and ensure that the temperature uniformity of the carrier plate is controlled within ±5℃. For example, as shown in Figure 3 , Figure 3 The temperature measuring points of the mass production line carrier plate are shown, for example, the temperature measuring points A2, D3, E7, A10, H11, I16 and L17. As shown in Figure 4 , Figure 3 based on the temperature measuring points, Figure 4 The actual measured carrier plate heating curve of the mass production line is shown, it can be seen that two-stage heating of the carrier plate is adopted to ensure temperature uniformity, and the temperature range after uniform heating is 7℃. The first process cavity 5 and the second process cavity 6 are provided with uniformly arranged hot wires with a diameter of 0.7mm, which can catalyze the cracking of the special gas when connected to a large current, so as to realize the deposition of the silicon nitride film.

[0076] The automatic device 8 comprises a large gantry 9, a turnover machine 10 and a carrier plate backflow rack 11. The large gantry 9 is responsible for grabbing the silicon wafer to complete the material taking and discharging of the silicon wafer. The turnover machine 10 is responsible for laying the vertical carrier plate flat to facilitate the material taking and discharging action of the large gantry 9. The buffer warehouse 12 is used to realize the transition of the carrier plate from the carrier plate backflow rack 11 to the turnover machine 10 and the turnover machine 10 to the main machine 1. The carrier plate backflow rack 11 is responsible for rotating the carrier plate from the unloading station to the loading station after unloading, so as to realize the recycling of the carrier plate.

[0077] The HoFCVD system can place 216 silicon wafers (model 210 half pieces) per carrier plate, and can coat 432 pieces at a time by adopting double-carrier vertical coating. The single-process cavity cycle is 96s, which can meet the production capacity of 700MW.

[0078] Example 1

[0079] A method for depositing high-quality silicon nitride film, which uses hot wire chemical vapor deposition technology, the specific steps are as follows:

[0080] First step: the hot wire arranged in the process cavity is preheated by small current 6A for 5s;

[0081] Second step: increase the current of the hot wire to a large current of 30A for heating, and at the same time, introduce ammonia into the process chamber, the flow rate of the ammonia is set to 5000sccm, and the pressure of the process chamber is controlled to 1 Pa for reaction for 5s;

[0082] Third step: keep the hot wire heated by the large current of 30A and introduce ammonia, the flow rate of the ammonia is set to 5000sccm, and at the same time, introduce silane into the process chamber, the flow rate of the silane is 500sccm, and the pressure of the process chamber is controlled to 1 Pa for reaction for 6s;

[0083] Fourth step: continue to keep the hot wire heated by the large current of 30A and continue to introduce ammonia, the flow rate of the ammonia is set to 5000sccm, and the process chamber is not controlled in pressure for reaction for 3s;

[0084] Fifth step: reduce the hot wire heated by the large current of 30A to the hot wire heated by the small current of 6A for buffering for 10s.

[0085] Example 2

[0086] A method for depositing high-quality silicon nitride thin film, which uses hot wire chemical vapor deposition technology, and the specific steps are as follows:

[0087] First step: preheat the hot wire arranged in the process chamber by a small current of 6.5A for 6s;

[0088] Second step: increase the current of the hot wire to a large current of 35A for heating, and at the same time, introduce ammonia into the process chamber, the flow rate of the ammonia is set to 5200sccm, and the pressure of the process chamber is controlled to 1.2 Pa for reaction for 6s;

[0089] Third step: keep the hot wire heated by the large current of 35A and introduce ammonia, the flow rate of the ammonia is set to 5200sccm, and at the same time, introduce silane into the process chamber, the flow rate of the silane is 530sccm, and the pressure of the process chamber is controlled to 1.2 Pa for reaction for 8s;

[0090] Fourth step: continue to keep the hot wire heated by the large current of 35A and continue to introduce ammonia, the flow rate of the ammonia is set to 5200sccm, and the process chamber is not controlled in pressure for reaction for 4s;

[0091] Fifth step: reduce the hot wire heated by the large current of 35A to the hot wire heated by the small current of 6.5A for buffering for 12s.

[0092] Example 3

[0093] A method for depositing high-quality silicon nitride thin film, which uses hot wire chemical vapor deposition technology, and the specific steps are as follows:

[0094] First step: preheat the hot wire arranged in the process chamber by a small current of 8A for 5.5s;

[0095] The second step is to increase the current of the hot wire to a large current 36A heating, and at the same time, ammonia gas is introduced into the process cavity, the flow rate of the ammonia gas is set to 5500sccm, and the pressure of the process cavity is controlled to 1.5Pa, and the reaction is 5.5s;

[0096] The third step is to keep the hot wire using a large current 36A heating and introducing ammonia gas, the flow rate of the ammonia gas is set to 5500sccm, and at the same time, silane is introduced into the process cavity, the flow rate of the silane is 550sccm, and the pressure of the process cavity is controlled to 1.5Pa, and the reaction is 7s;

[0097] The fourth step is to continue to keep the hot wire using a large current 36A heating and continue to keep introducing ammonia gas, the flow rate of the ammonia gas is set to 5500sccm, and the process cavity is not controlled pressure, and the reaction is 3.5s;

[0098] The fifth step is to reduce the hot wire using a large current 36A heating to using a small current 8A heating buffer 11s.

[0099] Therefore, the present application effectively solves the problem of decomposition of silane in preference to ammonia by precise control of the current and / or gas flow of the hot wire CVD process in multiple steps and stages, and improves the quality of the silicon nitride film. The present application prepares a high-quality silicon nitride film by optimizing the formula process, which can improve the light transmittance, corrosion resistance and other properties of the silicon nitride film, and further improve the electrical properties and service life of the crystalline silicon cell.

[0100] It should be noted that, in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to the process, method, article or equipment. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or equipment including the element.

[0101] The above is only an embodiment of the present application, which enables those skilled in the art to understand and implement the present application. Various modifications of the embodiment will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and features disclosed herein.

Claims

1. A method of depositing a high quality silicon nitride film, characterized by, The hot wire chemical vapor deposition technology comprises the following steps: S1: preheating the hot wire arranged in the process cavity by small current; S2: heating the preheated hot wire by large current, introducing ammonia into the process cavity, and controlling the pressure of the process cavity to react; S3: keeping the hot wire heated by large current and introducing ammonia, introducing silane into the process cavity, and controlling the pressure of the process cavity to react; S4: keeping the hot wire heated by large current and continuously introducing ammonia, and not controlling the pressure of the process cavity; S5: cooling the hot wire heated by large current to small current for heating buffering. In steps S1-S5, the small current ranges from 6A to 8A, and the large current ranges from 30A to 36A; in steps S2-S4, the flow rate of ammonia introduced is 5000-5500sccm, and the flow rate of silane introduced is 500-550sccm; in steps S2 and S3, the pressure of the process cavity is controlled to be 1-1.5Pa.

2. The method of claim 1, wherein the method is characterized by: Further comprising: Based on the thickness of the required silicon nitride film, repeating steps S2-S4.

3. The method of claim 1, wherein the method is characterized by: In step S1, the preheating time of the hot wire is 5-6s, in step S2, the reaction time of the ammonia introduced is 5-6s, in step S3, the reaction time of the silane introduced is 6-8s, in step S4, the time of continuously introducing ammonia is 3-4s, and in step S5, the heating buffering time is 10-12s.

4. The method of claim 1, wherein the method is characterized by: The diameter of the hot wire is 0.7mm.

5. A system for depositing high quality silicon nitride thin film using the method of depositing high quality silicon nitride thin film according to any one of claims 1 to 4, characterized by The system is a hot wire chemical vapor deposition system, comprising: A main machine table, which comprises a feeding cavity, a heating cavity, a uniform heating cavity, a process cavity and a discharging cavity which are sequentially and mutually communicated; An automatic device, which comprises a large gantry and a turnover machine on one side of the feeding cavity, a large gantry and a turnover machine on one side of the discharging cavity, and a carrier plate circulation rack below the main machine table, wherein each large gantry is configured to grab a silicon wafer to complete the feeding and discharging of the silicon wafer, each turnover machine is configured to turn the carrier plate from a vertical state to a horizontal state when the carrier plate is in the vertical state to facilitate the feeding and discharging of the large gantry, and the carrier plate circulation rack is configured to circulate the carrier plate from the unloading station to the loading station after unloading; At least two buffer warehouses, which are located at both ends of the carrier plate circulation rack and adjacent to the corresponding turnover machines, and are configured to realize the transition of the carrier plate from the carrier plate circulation rack to the turnover machine and from the turnover machine to the main machine table.

6. The system of claim 5, wherein, The heating cavity is heated by high power to rapidly heat the carrier plate to 110℃, and the uniform heating cavity is heated by low power to control the uniformity of the carrier plate temperature within ±5℃.

7. The system of claim 5, wherein, The system is a 700MW-capacity hot wire chemical vapor deposition system, which adopts double-carrier vertical film coating, each carrier plate places 216 silicon wafers, and the single-process cavity cycle is 96s.

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