Method and system for depositing high-quality silicon nitride film

Abstract

The invention relates to a method for depositing a high-quality silicon nitride film, which adopts a hot filament chemical vapor deposition technology and comprises the following steps of: preheating a hot filament arranged in a process cavity by adopting small current; the preheated hot wire is heated through large current, ammonia gas is introduced into the process cavity, and the pressure of the process cavity is controlled for reaction; heating the hot wire by adopting large current, introducing ammonia gas, introducing silane into the process cavity, and controlling the pressure of the process cavity for reaction; continuously keeping heating of the hot wire by adopting large current, continuously keeping introduction of ammonia gas, and not controlling the pressure of the process cavity; and cooling the hot wire heated by adopting the large current until the hot wire is heated and buffered by adopting the small current. In addition, the invention also relates to a HoFCVD system. The problem that silane is decomposed prior to ammonia gas is effectively solved, and the quality of the silicon nitride film is improved. The problems that the amorphous silicon film layer is damaged due to the fact that the temperature of the coating substrate of the PECVD equipment is too high and the productivity is insufficient due to the fact that the coating speed of the ALD equipment is low can also be perfectly solved.

Description

Technical Field

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

[0002] Crystalline silicon solar cells are exposed to 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 may cause corrosion to the battery components. These corrosion factors can damage the battery's electrodes, film layers, and packaging materials, thereby reducing the battery's photoelectric conversion efficiency and service life.

[0003] Silicon nitride has excellent chemical stability. It can remain stable in general acid and alkaline environments and will not easily react chemically with common acidic or alkaline substances. This property enables it to effectively prevent 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 solar cells, it can fit tightly on the surface of crystalline silicon and will not cause problems such as interface separation due to differences in thermal expansion coefficients. This enables it to play an anti-corrosion role for a long time and ensure the performance of crystalline silicon solar cells. In addition, silicon nitride film not only has an anti-corrosion effect, but also improves the photoelectric performance of the battery. It can be used 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] At present, the main equipment for preparing silicon nitride includes plasma enhanced chemical vapor deposition equipment (PECVD), hot filament chemical vapor deposition equipment (HoFCVD), and atomic layer deposition equipment (ALD). The silicon nitride film prepared by chemical vapor deposition has a dense microstructure, and its atoms are closely arranged to form a physical barrier that can effectively prevent the penetration of small molecules such as water and oxygen. The prepared silicon nitride film has been widely used on crystalline silicon cells as an anti-corrosion layer, anti-reflection layer, etc.

[0005] However, the coating rate of PECVD equipment is fast, but there is plasma damage to the surface of the battery cell, and the coating temperature is often 300-400℃, which limits its application areas. For example, the temperature requirement of the crystalline silicon heterojunction battery process route is lower than 200℃, otherwise it will damage the amorphous silicon layer. The ALD equipment has good film uniformity and high film thickness control accuracy, but the deposition rate is slow and is not suitable for large-scale thin film deposition applications. The production capacity is limited, and the equipment cost is high, the investment is large, and the cost performance is low. HoFCVD equipment has low cost and fast film deposition rate. At the same production capacity, the price is only half of PECVD. Moreover, the coating process of HoFCVD equipment is gentle, without plasma damage, and can reduce surface defects caused by the thin film deposition process. In addition, HoFCVD equipment is compatible with both high-temperature and low-temperature silicon nitride deposition processes, and has a wide range of applications. Therefore, HoFCVD equipment has become the first choice for depositing silicon nitride films.

[0006] However, the HoFCVD device uses a hot wire under a large current, and the temperature rises rapidly to 1800-2200°C. The reaction gas is cracked by high-temperature catalysis to form active groups. However, after a large current is passed through the hot wire, it will undergo a process of rapid rise and reach a stable voltage. During the voltage rise stage, the temperature of the hot wire is relatively low, and the decomposition temperature of silane (400°C) is lower than the decomposition temperature of ammonia (800°C). Therefore, at this stage, silane will preferentially decompose and deposit on the substrate to form an amorphous silicon film, resulting in the poor quality of the prepared silicon nitride film, which is easily corroded by acids and alkalis and has slightly poor light transmittance.

[0007] Therefore, it is urgent to design a process that can deposit and prepare high-quality silicon nitride films to solve the above problems. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a silicon nitride film of better quality by optimizing the formulation process, so as to improve the light transmittance, corrosion resistance, etc. of the silicon nitride film, thereby improving the electrical performance and service life of crystalline silicon cell pieces.

[0009] In order to solve the above technical problems or achieve the above objectives, the present invention adopts the following technical solutions:

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

[0011] S1: preheating the hot wire arranged in the process chamber with a small current;

[0012] S2: The preheated hot wire is heated by a large current and ammonia is introduced into the process chamber, and the pressure of the process chamber is controlled to react;

[0013] S3: Keep the hot wire heated by a large current and introduce ammonia, introduce silane into the process chamber, and control the pressure of the process chamber to react;

[0014] S4: Continue to heat the hot wire with a large current and continue to introduce ammonia gas, and do not control the pressure of the process chamber;

[0015] S5: Cooling down the hot wire heated by a large current to a temperature where a small current is used for heating buffering.

[0016] In one embodiment of the present invention, the method further comprises:

[0017] Based on the desired thickness of the silicon nitride film, steps S2-S4 are repeated.

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

[0019] In one embodiment of the present invention, the time for preheating the hot wire in step S1 is 5-6s, the time for introducing ammonia to react in step S2 is 5-6s, the time for introducing silane to react in step S3 is 6-8s, the time for continuing to introduce ammonia in step S4 is 3-4s, and the time for heating buffer in step S5 is 10-12s.

[0020] In one embodiment of the present invention, in steps S2-S4, the flow rate of the introduced ammonia gas is 5000-5500 sccm, and the flow rate of the introduced silane is 500-550 sccm.

[0021] In one embodiment of the present invention, in steps S2 and S3, the pressure of the process chamber is controlled to be 1-1.5Pa.

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

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

[0024] A main machine platform, which includes a feeding chamber, a heating chamber, a heat-uniform chamber, a process chamber and a discharging chamber which are interconnected in sequence;

[0025] Automation equipment, the automation equipment includes a large gantry and a flipper located on one side of the feed chamber, a large gantry and a flipper located on one side of the discharge chamber, and a carrier reflow rack located under the main machine, wherein each large gantry is configured to grab silicon wafers to complete the picking and unloading of silicon wafers, each flipper is configured to flip the carrier to a horizontal state when the carrier is in an upright state so as to facilitate the large gantry to pick and unload, and the carrier reflow rack is configured to unload the carrier from the unloading station and rotate it back to the loading station to realize the recycling of the carrier;

[0026] At least two buffer bins are located at both ends of the carrier board reflow rack and adjacent to the corresponding flipping machines. The buffer bins are configured to realize the transition of the carrier board from the carrier board reflow rack to the flipping machine, and from the flipping machine to the main station.

[0027] In one embodiment of the present invention, the heating chamber is heated at high power to quickly heat the carrier to 110° C., and the uniform heating chamber is heated at low power to ensure that the temperature uniformity of the carrier is controlled within ±5° C.

[0028] In one embodiment of the present invention, the system is a hot-wire chemical vapor deposition system with a production capacity of 700MW. The hot-wire chemical vapor deposition system adopts double-carrier vertical coating, wherein each carrier is placed with 216 silicon wafers and the cycle of a single process chamber is 96s.

[0029] The technical solution provided by the present invention has the following advantages compared with the prior art:

[0030] The present invention effectively solves the problem of silane decomposing before ammonia by precisely controlling the current and / or gas flow in multiple steps and stages of the hot filament CVD (HoFCVD) process, thereby improving the quality of the silicon nitride film.

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

[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the description of the embodiments or the prior art are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1A schematic flow chart of a method for depositing a high-quality silicon nitride film provided by an embodiment of the present invention is shown;

[0035] Figure 2 Shows the use of Figure 1 A schematic diagram of the structure of a HoFCVD system for high-quality silicon nitride film deposition using a method;

[0036] Figure 3 Shows the use of Figure 2 Schematic diagram of the temperature measurement points of the carrier board of the mass production line of the HoFCVD system;

[0037] Figure 4 Shown based on Figure 3 Schematic diagram of the measured substrate heating curve at the substrate temperature measurement points on the mass production line.

[0038] Among them, 1. Main machine; 2. Feed chamber; 3. Heating chamber; 4. Uniform heating chamber; 5. First process chamber; 6. Second process chamber; 7. Discharge chamber; 8. Automation equipment; 9. Large gantry; 10. Turning machine; 11. Plate carrier reflow rack; 12. Buffer bin. DETAILED DESCRIPTION

[0039] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the embodiments of the present invention will be further described below. It should be noted that the embodiments of the present invention 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 to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0041] like Figure 1 As shown, an embodiment of the present invention provides a method for depositing a high-quality silicon nitride film, the method using hot wire chemical vapor deposition technology, comprising the following steps:

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

[0043] S2: The preheated hot wire is heated by a large current and ammonia is introduced into the process chamber, and the pressure of the process chamber is controlled to react;

[0044] S3: Keep the hot wire heated by a large current and introduce ammonia, introduce silane into the process chamber, and control the pressure of the process chamber to react;

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

[0046] S5: Cooling down the hot wire heated by a large current to a temperature where a small current is used for heating buffering.

[0047] The method of the invention effectively solves the problem of silane decomposing before ammonia by precisely controlling the current and / or gas flow in multiple steps and stages of the hot filament CVD (HoFCVD) process, thereby improving the quality of the silicon nitride film.

[0048] In the above embodiment of the present invention, preferably, the method further comprises: repeating steps S2-S4 based on the desired thickness of the silicon nitride film. According to the desired target thickness of the silicon nitride film, the operations of steps S2 to S4 are repeated. This repeated process can accurately control the thickness of the film to achieve the desired target thickness.

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

[0050] In the above-mentioned embodiment of the present invention, the time for preheating the hot wire in step S1 is 5-6s, preferably 5s; the time for introducing ammonia to react in step S2 is 5-6s, preferably 5s; the time for introducing silane to react in step S3 is 6-8s, preferably 6s; the time for continuing to introduce ammonia in step S4 is 3-4s, preferably 3s; the time for heating buffer in step S5 is 10-12s, preferably 10s.

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

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

[0053] In the above-mentioned embodiment of the present invention, the diameter of the heating wire is 0.7 mm.

[0054] like Figure 2 As shown, the embodiment of the present invention also provides a method of using Figure 1 The method for depositing a high-quality silicon nitride film is shown in a system for depositing a high-quality silicon nitride film, which is a hot wire chemical vapor deposition system, comprising:

[0055] A mainframe 1, the mainframe 1 comprises a feeding chamber 2, a heating chamber 3, a uniform heating chamber 4, a process chamber (a first process chamber 5 and a second process chamber 6) and a discharging chamber 7 which are sequentially connected to each other;

[0056] The automation equipment 8 includes a large gantry 9 and a flipper 10 located on one side of the feed chamber 2, a large gantry 9 and a flipper 10 located on one side of the discharge chamber 7, and a carrier reflow rack 11 located below the main platform 1, wherein each large gantry 9 is configured to grab silicon wafers to complete the picking and unloading of silicon wafers, each flipper 10 is configured to flip the carrier to a horizontal state when the carrier is in an upright state so as to facilitate the large gantry 9 to pick and unload, and the carrier reflow rack 11 is configured to unload the carrier from the unloading station and rotate it to the loading station to realize the recycling of the carrier;

[0057] Two buffer bins 12 are located at both ends of the carrier board reflow rack 11 and adjacent to the corresponding flipping machine 10 . The buffer bins 12 are configured to realize the transition of the carrier board from the carrier board reflow rack 11 to the flipping machine 10 and from the flipping machine 10 to the main station 1 .

[0058] The HoFCVD system for depositing silicon nitride thin films in the present invention can match the crystalline silicon heterojunction solution with a production capacity of 700MW, and can perfectly solve the problems of damage to the amorphous silicon film layer caused by excessively high temperature of the coating substrate of the PECVD equipment and insufficient production capacity caused by slow coating rate of the ALD equipment.

[0059] In the above embodiment of the present invention, the heating chamber 3 heats the carrier quickly to 110° C. through high-power heating, and the uniform heating chamber 4 heats the carrier at low power to ensure that the temperature uniformity is controlled within ±5° C.

[0060] In the above embodiment of the present invention, the system is a hot wire chemical vapor deposition system with a production capacity of 700MW. The hot wire chemical vapor deposition system adopts double-carrier vertical coating, in which each carrier is placed with 216 silicon wafers and the cycle of a single process chamber is 96s.

[0061] The above technical solution of the present invention is described in detail below through specific embodiments.

[0062] In order to solve the problem of amorphous silicon film deposition caused by silane decomposing before ammonia during the heating process of the hot wire, the present invention optimizes the process formula as follows: a method for depositing high-quality silicon nitride film, the method uses hot wire chemical vapor deposition technology, and the specific steps are as follows.

[0063] Step 1: Preheat the hot wire arranged in the process chamber with a small current of 6-8A, and the process time is 5-6s.

[0064] This step is to preheat the hot wire initially so that it enters a relatively stable initial state and prepares for the subsequent deposition process.

[0065] Step 2: Increase the current of the hot wire to a high current of 30-36A for heating, and at the same time introduce ammonia into the process chamber. The flow rate of ammonia is set to 5000-5500sccm, and the pressure of the process chamber is controlled to 1-1.5Pa for reaction for 5-6s.

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

[0067] Step 3: Keep the hot wire heated with a large current of 30-36A and introduce ammonia with a flow rate of 5000-5500sccm. At the same time, introduce silane into the process chamber with a flow rate of 500-550sccm. Control the pressure of the process chamber to 1-1.5Pa and react for 6-8s.

[0068] In this step, the flow rates of ammonia and silane are controlled to allow the two to decompose and react in an orderly manner around the hot wire. In this stage, silane and ammonia begin to react chemically under the high-temperature catalytic cracking effect of the hot wire, and thin film deposition is performed on the substrate. Since the hot wire has been raised to the target temperature in advance, the situation in which silane decomposes before ammonia due to the low-temperature stage of the hot wire is avoided, and there is a high concentration of active nitrogen atoms in the process chamber, which helps to form a high-quality silicon nitride film.

[0069] Step 4: Continue to heat the hot wire with a large current of 30-36A and continue to introduce ammonia. The flow rate of ammonia is set to 5000-5500sccm, and the pressure of the process chamber is not controlled. The reaction lasts 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 film during the gas evacuation stage.

[0071] Step 5: Cool down the hot wire heated by a large current of 30-36A to a small current of 6-8A for heating buffering for 10-12s.

[0072] This step serves as a buffer stage to prevent the hot wire from working at high current for a long time, which may cause excessive elongation of the hot wire and catalysis that may affect its service life. It can also reduce the substrate temperature and prevent the high-temperature film layer on the substrate from being damaged due to excessive radiation from the hot wire.

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

[0074] In addition, refer again Figure 2The present invention uses a HoFCVD system to prepare a silicon nitride film, and the HoFCVD system includes a main machine 1 and an automation device 8.

[0075] The main machine 1 includes a feed chamber 2, a heating chamber 3, a uniform heating chamber 4, a first process chamber 5, a second process chamber 6 and a discharge chamber 7. The feed chamber 2 and the discharge chamber 7 are responsible for completing the transition between vacuum and atmosphere. The present invention adopts two-stage heating to ensure temperature uniformity: the heating chamber 3 is heated by high power to quickly heat the carrier to 110°C, and the uniform heating chamber 4 applies low power to make the area with higher carrier temperature cool faster than the area with lower carrier temperature, so as to achieve the goal of uniform heating and ensure that the carrier temperature uniformity is controlled within ±5°C. For example, Figure 3 As shown, Figure 3 The temperature measurement points of the carrier board of the mass production line are shown, for example, the temperature measurement points are A2, D3, E7, A10, H11, I16 and L17. Figure 4 As shown, based on Figure 3 The temperature measurement points, Figure 4 The measured carrier heating curve of the mass production line is shown. It can be seen that the two-stage heating carrier is used to ensure temperature uniformity, and the temperature difference after uniform heating is 7°C. The first process chamber 5 and the second process chamber 6 are equipped with uniformly arranged hot wires with a diameter of 0.7mm. When a large current is connected, the special gas introduced can be catalytically cracked to achieve the deposition of silicon nitride film.

[0076] The automation equipment 8 includes a large gantry 9, a turning machine 10 and a carrier reflow rack 11. The large gantry 9 is responsible for grabbing silicon wafers and completing the material collection and discharge of silicon wafers. The turning machine 10 is responsible for flattening the vertical carrier to facilitate the large gantry 9 to perform material collection and discharge actions. The buffer bin 12 is used to realize the transition of the carrier from the carrier reflow rack 11 to the turning machine 10, and the turning machine 10 to the main station 1. The carrier reflow rack 11 is responsible for unloading the carrier from the unloading station and rotating it to the loading station to realize the recycling of the carrier.

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

[0078] Example 1

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

[0080] Step 1: preheat the hot wire arranged in the process chamber with a small current of 6A for 5s;

[0081] Step 2: Increase the current of the hot wire to a maximum current of 30A for heating, and at the same time introduce ammonia into the process chamber. The flow rate of ammonia is set to 5000sccm, and the pressure of the process chamber is controlled to 1Pa for 5s.

[0082] Step 3: Keep the hot wire heated with a high current of 30A and introduce ammonia gas with a flow rate of 5000sccm. At the same time, introduce silane into the process chamber with a flow rate of 500sccm. Control the pressure of the process chamber to 1Pa for 6s.

[0083] Step 4: Continue to heat the hot wire with a high current of 30A and continue to introduce ammonia gas. The flow rate of ammonia gas is set to 5000sccm, and the pressure of the process chamber is not controlled. The reaction lasts for 3s.

[0084] Step 5: Cool down the hot wire heated by a large current of 30A to a small current of 6A for heating buffer for 10s.

[0085] Example 2

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

[0087] Step 1: preheat the hot wire arranged in the process chamber with a small current of 6.5A for 6s;

[0088] Step 2: Increase the current of the hot wire to a maximum current of 35A for heating, and at the same time introduce ammonia into the process chamber. The flow rate of ammonia is set to 5200sccm, and the pressure of the process chamber is controlled to 1.2Pa for a reaction of 6s.

[0089] Step 3: Keep the hot wire heated with a high current of 35A and introduce ammonia gas with a flow rate of 5200sccm. Simultaneously, introduce silane into the process chamber with a flow rate of 530sccm. Control the pressure of the process chamber to 1.2Pa for 8s.

[0090] Step 4: Continue to heat the hot wire with a high current of 35A and continue to introduce ammonia gas. The flow rate of ammonia gas is set to 5200sccm, and the pressure of the process chamber is not controlled. The reaction lasts for 4s.

[0091] Step 5: Cool down the hot wire heated by a large current of 35A to a small current of 6.5A for heating buffer for 12s.

[0092] Example 3

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

[0094] Step 1: preheat the hot wire arranged in the process chamber with a small current of 8A for 5.5s;

[0095] Step 2: Increase the current of the hot wire to a maximum current of 36A for heating, and introduce ammonia into the process chamber at the same time. The flow rate of ammonia is set to 5500sccm, and the pressure of the process chamber is controlled to 1.5Pa for a reaction time of 5.5s.

[0096] Step 3: Keep the hot wire heated with a high current of 36A and introduce ammonia gas with a flow rate of 5500sccm. At the same time, introduce silane into the process chamber with a flow rate of 550sccm. Control the pressure of the process chamber to 1.5Pa for 7s.

[0097] Step 4: Continue to heat the hot wire with a high current of 36A and continue to introduce ammonia gas. The flow rate of ammonia gas is set to 5500sccm, and the pressure of the process chamber is not controlled. The reaction lasts for 3.5s.

[0098] Step 5: Cool down the hot wire heated by a large current of 36A to a small current of 8A for heating buffer for 11s.

[0099] It can be seen that the present invention effectively solves the problem of silane decomposing before ammonia by precisely controlling the current and / or gas flow rate in multiple steps and stages of the hot wire CVD process, thereby improving the quality of the silicon nitride film. The present invention optimizes the formulation process to prepare a silicon nitride film of good quality, thereby improving the light transmittance and corrosion resistance of the silicon nitride film, and thus improving the electrical performance and service life of the crystalline silicon cell.

[0100] It should be noted that, in this article, 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 these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusions, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to the process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

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

Claims

1. A method for depositing high-quality silicon nitride thin films, characterized in that: Using hot-wire chemical vapor deposition technology, including: S1: preheating the hot wire arranged in the process chamber with a small current; S2: The preheated hot wire is heated by a large current and ammonia is introduced into the process chamber, and the pressure of the process chamber is controlled to react; S3: Keep the hot wire heated by a large current and introduce ammonia, introduce silane into the process chamber, and control the pressure of the process chamber to react; S4: Continue to heat the hot wire with a large current and continue to introduce ammonia gas, and do not control the pressure of the process chamber; S5: Cooling down the hot wire heated by a large current to a temperature where a small current is used for heating buffering.

2. The method for depositing a high-quality silicon nitride film according to claim 1, characterized in that: Also includes: Based on the desired thickness of the silicon nitride film, steps S2-S4 are repeated.

3. The method for depositing a high-quality silicon nitride film according to claim 1, characterized in that: In steps S1-S5, the range of the small current is 6-8A, and the range of the large current is 30-36A.

4. The method for depositing a high-quality silicon nitride film according to claim 1, characterized in that: The time for preheating the hot wire in step S1 is 5-6s, the time for introducing ammonia to react in step S2 is 5-6s, the time for introducing silane to react in step S3 is 6-8s, the time for continuing to introduce ammonia in step S4 is 3-4s, and the time for heating buffer in step S5 is 10-12s.

5. The method for depositing a high-quality silicon nitride film according to claim 1, characterized in that: In steps S2-S4, the flow rate of the ammonia gas is 5000-5500 sccm, and the flow rate of the silane gas is 500-550 sccm.

6. The method for depositing a high-quality silicon nitride film according to claim 1, characterized in that: In steps S2 and S3, the pressure of the process chamber is controlled at 1-1.5Pa.

7. The method for depositing a high-quality silicon nitride film according to claim 1, characterized in that: The diameter of the hot wire is 0.7 mm.

8. A system for depositing a high-quality silicon nitride film using the method for depositing a high-quality silicon nitride film according to any one of claims 1 to 7, characterized in that: The system is a hot wire chemical vapor deposition system comprising: A main machine platform, the main machine platform comprising a feeding chamber, a heating chamber, a heat-uniform chamber, a process chamber and a discharging chamber which are sequentially interconnected; Automation equipment, the automation equipment includes a large gantry and a flipper located on one side of the feed chamber, a large gantry and a flipper located on one side of the discharge chamber, and a carrier reflow rack located under the main machine, wherein each of the large gantry is configured to grab silicon wafers to complete the picking and unloading of silicon wafers, each of the flippers is configured to flip the carrier to a horizontal state when the carrier is in an upright state so as to facilitate the large gantry to pick and unload, and the carrier reflow rack is configured to unload the carrier from the unloading station and rotate it to the loading station to realize the recycling of the carrier; At least two buffer bins are located at both ends of the carrier reflow rack and adjacent to the corresponding flipping machines, and the buffer bins are configured to realize the transition of the carrier from the carrier reflow rack to the flipping machine, and from the flipping machine to the main station.

9. The system according to claim 8, characterized in that The heating chamber heats the carrier plate to 110° C. quickly by high-power heating, and the uniform heating chamber heats the carrier plate to ensure that the temperature uniformity is controlled within ±5° C. by low-power heating.

10. The system according to claim 8, characterized in that The system is a hot wire chemical vapor deposition system with a production capacity of 700MW. The hot wire chemical vapor deposition system adopts double-carrier vertical coating, wherein each carrier is placed with 216 silicon wafers and the cycle of a single process chamber is 96s.

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