Method and equipment for preparing low-temperature silicon nitride film

Abstract

The invention relates to a method for preparing a low-temperature silicon nitride film, which adopts a hot filament chemical vapor deposition technology and comprises the following steps of: placing a substrate on a support plate and feeding the support plate into a vacuum reaction chamber; introducing required process gas into the vacuum reaction chamber, wherein the process gas comprises any one or both of ammonia gas and nitrogen gas, hydrogen gas and silane; and dynamically adjusting the temperature of the hot filament, and depositing on the substrate to obtain the required silicon nitride film. In addition, the invention also relates to equipment for preparing the low-temperature silicon nitride film by adopting the method for preparing the low-temperature silicon nitride film. The hot filament chemical vapor deposition technology is adopted, the compact silicon nitride thin film can be prepared when the temperature of the substrate is higher than the room temperature, the application field of equipment is greatly widened, the silicon nitride thin film deposited under the condition that the temperature of the substrate is kept low can be produced under the proper air pressure, and the production efficiency is improved. And manufacturing of HBC cells and perovskite cells in the photovoltaic field is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor material preparation, and more specifically, relates to a method and equipment for preparing silicon nitride thin films at low temperature, which is suitable for the manufacturing process of high-efficiency solar cells in the photovoltaic field, such as HBC (heterojunction back contact cells) and perovskite cells. Background Art

[0002] Silicon nitride thin films are widely used in semiconductor devices due to their excellent optical properties and good dielectric properties, especially in the field of photovoltaic technology, as passivation layers or anti-reflection layers. Traditional methods for preparing silicon nitride thin films mainly include sputtering coating in physical vapor deposition technology, and plasma chemical vapor deposition (PECVD), high-temperature thermal chemical vapor deposition (HTCVD), and low-pressure chemical vapor deposition (LPCVD) in chemical vapor deposition technology. Although these methods have shown high deposition efficiency and good film quality within their respective applicable ranges, they generally have a significant limitation - the substrate heating temperature is generally high, usually reaching above 200°C.

[0003] For example, in magnetron sputtering (PVD), high-energy particles bombard the target material, causing the target atoms to evaporate and deposit on the substrate to form a thin film. This method is simple to operate, but the target material is expensive and there is a phenomenon that high-energy particles damage the substrate.

[0004] In plasma chemical vapor deposition (PECVD), plasma is used to excite the reaction gas to produce a chemical reaction, thereby depositing a thin film on the substrate. Although the deposition temperature can be reduced to a certain extent, it still needs to be maintained above 200°C, which cannot fully meet the substrate temperature requirements of HBC cells and perovskite cells.

[0005] In the high temperature thermal chemical vapor deposition method (HTCVD), a high temperature of 2000-2500°C is required to promote the chemical reaction, which is obviously not suitable for the preparation of photovoltaic cells that require a low temperature environment.

[0006] In low-pressure chemical vapor deposition (LPCVD), high-quality thin films can be obtained by depositing thin films through chemical reactions in a low-pressure environment. However, when depositing silicon nitride films, the substrate temperature must be higher than 890°C, which is not suitable for low-temperature sensitive materials.

[0007] For HBC cells (heterojunction back contact cells) and perovskite cells, which are currently developing rapidly and are regarded as the mainstream direction of future photovoltaic technology, their preparation process has more stringent requirements on substrate temperature. Specifically, in order to protect the sensitive functional layers in the cell structure from high temperature damage and ensure the high efficiency of the cell, the substrate temperature must be controlled below 200°C during the preparation of these new photovoltaic cells. However, the existing silicon nitride thin film preparation technology is difficult to meet this demand, which has become one of the key bottlenecks restricting the further development and commercialization of the above two advanced photovoltaic cells.

[0008] It can be seen that the existing silicon nitride film preparation technology has obvious shortcomings when facing the manufacture of new photovoltaic cells that require a low temperature environment. Therefore, developing a new method that can effectively prepare silicon nitride films under low temperature conditions is of great significance for promoting the development of HBC cells and perovskite cells and similar temperature-sensitive semiconductor industries. Summary of the invention

[0009] In view of the deficiencies in the prior art, an object of the present invention is to provide a method and an apparatus for preparing a low-temperature silicon nitride film.

[0010] In order to solve the above technical problems or achieve the above objectives, the present invention adopts the following technical solutions:

[0011] According to one aspect of the present invention, there is provided a method for preparing a low-temperature silicon nitride film, the method using a hot wire chemical vapor deposition technique, comprising:

[0012] Placing the substrate on a carrier and placing the carrier into a vacuum reaction chamber;

[0013] Introducing required process gases into the vacuum reaction chamber, wherein the process gases include: any one or both of ammonia and nitrogen, hydrogen and silane;

[0014] The temperature of the hot wire is dynamically adjusted to deposit the desired silicon nitride film on the substrate.

[0015] In one embodiment of the present invention, the method further comprises:

[0016] The temperature of the carrier in the vacuum reaction chamber is controlled so that the temperature of the carrier gradually rises to the set value. After the temperature of the carrier reaches and is maintained at the set value, the required process gas is introduced into the vacuum reaction chamber, and the cooling gas is further sprayed onto the substrate surface, thereby jointly controlling the substrate temperature.

[0017] In one embodiment of the present invention, the substrate is a single crystal silicon wafer, the carrier temperature is controlled at 0-500°C, and the substrate temperature is controlled above room temperature and does not exceed 200°C.

[0018] In one embodiment of the present invention, the refractive index of the obtained silicon nitride film is 1.6-2.6.

[0019] In one embodiment of the present invention, the vacuum degree of the vacuum reaction chamber is controlled at 0-10Pa.

[0020] According to another aspect of the present invention, there is provided a device for preparing a low-temperature silicon nitride film using the method for preparing a low-temperature silicon nitride film as described above, wherein the device uses a hot wire chemical vapor deposition technology for coating, and comprises:

[0021] a conveying system configured to place the substrate on a carrier and convey the carrier into the vacuum reaction chamber;

[0022] A gas homogenizing system, which is disposed in the vacuum reaction chamber and is configured to introduce required process gases into the vacuum reaction chamber, wherein the process gases include: any one or both of ammonia and nitrogen, hydrogen and silane;

[0023] The reaction system is arranged in a vacuum reaction chamber and is configured to dynamically adjust the temperature of the hot wire.

[0024] An automation system is communicatively connected with the conveying system, the gas homogenizing system and the reaction system.

[0025] In one embodiment of the present invention, the device further comprises:

[0026] A temperature control system is configured to control the temperature of the carrier and the temperature of the substrate, and the temperature control system is communicatively connected with the automation system.

[0027] In one embodiment of the present invention, the temperature control system includes a contact temperature control device and a gas cooling system. The contact temperature control device is in direct contact with the carrier to control the temperature of the carrier and thus the temperature of the substrate on the carrier. The gas cooling system cooperates with the gas uniformization system and further controls the substrate temperature by spraying cooling gas on the substrate surface.

[0028] In one embodiment of the present invention, the gas uniformization system adopts a multi-partitioned independent gas transportation system, and each partition structure adopts independent gas pipelines for different gases. During the coating reaction, the gas uniformization system passes the process gas into the vacuum reaction chamber through the corresponding gas pipelines.

[0029] In one embodiment of the present invention, the automation system includes a hardware part and a software part. The hardware part includes a PLC and sensors, pump groups and transmission devices controlled by the PLC. The software part is configured to implement process control, recipe compilation, data monitoring and data analysis and is configured to automatically execute the entire process of substrate loading, coating process and substrate unloading according to the compiled recipe.

[0030] The technical solution provided by the present invention has the following advantages compared with the prior art:

[0031] (1) The present invention adopts hot wire chemical vapor deposition technology, which can realize the preparation of dense silicon nitride film when the substrate temperature is above room temperature, greatly improving the application field of the equipment.

[0032] (2) The deposition gas pressure in the present invention is low, dust is not easily generated, and the cavity maintenance cost is low.

[0033] (3) In the present invention, nitrogen (N2) and / or ammonia (NH3) can be used as nitrogen sources, which has good safety and low gas cost.

[0034] (4) The overall cost of the HoFCVD (hot wire chemical vapor deposition) equipment used in the present invention is low.

[0035] (5) The present invention can solve the problem of uncontrollable spontaneous reactions of multiple reaction gases or process gases before entering the reaction chamber. The present invention ensures that such spontaneous reactions are effectively prevented from occurring during the entire reaction process by adopting a process formula that reduces the reaction gas pressure and combining the designed layout between the hot wire and the carrier. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or 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 creative work.

[0038] Figure 1 A schematic flow chart of a method for preparing a low-temperature silicon nitride film provided by an embodiment of the present invention is shown;

[0039] Figure 2 Shows the use of Figure 1 A schematic diagram of the structure of a gas homogenization system in an apparatus for preparing a low-temperature silicon nitride thin film by a method;

[0040] Figure 3 Shows Figure 2 Structural schematic diagram of a single partition structure in a uniform gas system.

[0041] Among them, 1. vacuum reaction chamber; 2. uniform gas system; 3. partition structure; 4. gas pipeline. DETAILED DESCRIPTION

[0042] In order to more clearly understand the above-mentioned purposes, features and advantages of the present disclosure, the embodiments of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0044] like Figure 1 As shown, in one embodiment of the present invention, a method for preparing a low-temperature silicon nitride film is provided, the method using a hot wire chemical vapor deposition technology, comprising:

[0045] S101: placing a substrate on a carrier and sending the carrier into a vacuum reaction chamber;

[0046] S102: introducing required process gases into the vacuum reaction chamber, wherein the process gases include: any one or both of ammonia and nitrogen, hydrogen and silane;

[0047] S103: Dynamically adjust the temperature of the hot wire to deposit the required silicon nitride film on the substrate.

[0048] Hot Wire Chemical Vapor Deposition (HoFCVD) is a technology that uses a high-temperature metal wire (hot wire) as a catalyst to decompose the reaction gas or process gas. In this process, the reaction gas or process gas is activated when it contacts the high-temperature metal wire (hot wire) to generate active groups. These active groups then migrate from the surface of the hot wire to the surface of the substrate, where they undergo chemical reactions and eventually form the desired thin film. Since the generation and deposition of active groups occur on the hot wire and the substrate respectively, a significant advantage of this technology is that there are no strict requirements for substrate temperature and deposition pressure, so that the deposition of thin films can be achieved at substrate temperatures above room temperature and under appropriate pressure conditions. This feature makes hot wire chemical vapor deposition an ideal choice for preparing thin films of temperature-sensitive materials, especially in applications where a low substrate temperature needs to be maintained, such as the manufacture of HBC cells and perovskite cells in the photovoltaic field.

[0049] Therefore, through the method of the above embodiment of the present invention, the present invention adopts hot wire chemical vapor deposition technology, which can realize the preparation of dense silicon nitride film when the substrate temperature is above room temperature, greatly improving the application field of the equipment; and the deposition gas pressure in the present invention is low, dust is not easily generated, and the cavity maintenance cost is low; nitrogen and / or ammonia can be used as nitrogen sources in the present invention, which has good safety and low gas cost.

[0050] In the above embodiment of the present invention, preferably, the method further comprises: controlling the carrier temperature in the vacuum reaction chamber, gradually raising the carrier temperature to a set value, and after the carrier temperature reaches and maintains at the set value, introducing the required process gas into the vacuum reaction chamber, and further spraying the substrate surface with cooling gas (e.g., high-purity nitrogen), thereby jointly controlling the substrate temperature. Preferably, the substrate is a single crystal silicon wafer, the carrier temperature can be controlled at 0-500°C, and the substrate temperature can be controlled above room temperature and not more than 200°C.

[0051] In the above embodiments of the present invention, preferably, the vacuum degree of the vacuum reaction chamber is controlled at 0-10Pa, and more preferably, the vacuum degree of the vacuum reaction chamber is 5Pa.

[0052] In the above embodiment of the present invention, the refractive index of the silicon nitride film prepared by the above method is adjustable, and the refractive index ranges from 1.6 to 2.6.

[0053] In addition, an embodiment of the present invention also provides a device for preparing a low-temperature silicon nitride film using the method for preparing a low-temperature silicon nitride film as described above, the device uses hot wire chemical vapor deposition technology for coating, and includes: a conveying system, a gas homogenization system, a reaction system, a temperature control system, and an automation system. Among them: the conveying system is configured to place the substrate on a carrier and convey the carrier into a vacuum reaction chamber; the gas homogenization system is arranged in the vacuum reaction chamber and is configured to introduce the required process gas into the vacuum reaction chamber, wherein the process gas includes: any one or both of ammonia and nitrogen, hydrogen and silane; the reaction system is arranged in the vacuum reaction chamber, and the reaction system is configured to dynamically adjust the temperature of the hot wire; the temperature control system is configured to control the carrier temperature and the substrate temperature; the automation system is connected in communication with the conveying system, the gas homogenization system, the reaction system, and the temperature control system.

[0054] In the above-mentioned device of the present invention, preferably, the temperature control system includes a contact temperature control device and a gas cooling system, the contact temperature control device is in direct contact with the carrier to control the temperature of the carrier and thus the temperature of the substrate on the carrier, and the gas cooling system cooperates with the gas homogenization system to spray cooling gas onto the substrate surface to further control the substrate temperature. That is, the present invention can realize the control of the substrate temperature by controlling the carrier temperature and spraying cooling gas onto the substrate surface.

[0055] In the above-mentioned device of the present invention, preferably, Figure 2-3As shown, the gas homogenizing system 2 adopts a multi-partitioned independent gas transport system. For example, it is preferably designed with four partition structures 3, and each partition structure 3 adopts independent gas pipelines 4 for different gases. The gas homogenizing system 2 passes the process gas into the vacuum reaction chamber 1 through the respective corresponding gas pipelines 4 during the coating reaction. Therefore, the four partition structures 3 in the gas homogenizing system 2 can achieve uniform distribution of the gas entering the vacuum reaction chamber 1. Gas pipelines 4 for different gases are arranged on each partition structure 3, so that different gases enter the vacuum reaction chamber 1 through their respective corresponding gas pipelines 4, thereby avoiding uncontrollable spontaneous reactions between different gases before entering the vacuum reaction chamber 1.

[0056] In the above-mentioned equipment of the present invention, preferably, the automation system includes a hardware part and a software part, the hardware part includes a PLC and sensor devices, a pump group and a transmission device controlled by the PLC, and the software part is configured to realize process flow control, recipe compilation, data monitoring and data analysis and is configured to automatically execute the entire process flow of substrate loading, coating process and substrate unloading according to the compiled recipe.

[0057] The above technical solution of the present invention is described in detail below through specific embodiments.

[0058] In the specific embodiment of the present invention, a self-developed HoFCVD device is used, which is composed of a uniform gas system, a reaction system, a temperature control system, a chamber structure, and an automation system.

[0059] like Figure 2-3 As shown, the design of the uniform gas system 2 adopts a multi-partitioned independent gas transport system, for example, four partition structures 3, each partition structure 3 further subdivides independent gas pipelines 4 for different gases, aiming to physically isolate gases that can react with each other, avoid premature mixing between gases, thereby reducing unnecessary side reactions, and improving the purity and quality of the target product. At the same time, different gases enter the vacuum reaction chamber 1 through different gas pipelines 4, and a more uniform gas distribution can also be achieved. Such a design not only ensures the safety and stability of gas transportation, but also greatly improves the controllability and efficiency of the reaction process and improves the uniformity of the film.

[0060] The reaction system consists of a self-developed domestic hot wire and a fixed structure. By adjusting the power supply, the temperature of the hot wire can be freely adjusted to support the requirements of the hot wire temperature for the decomposition of different process gases.

[0061] The temperature control system is divided into a contact temperature control device and a gas cooling system. The contact temperature control device can monitor the temperature of the carrier in real time and perform cooling and heating operations by directly contacting the carrier to control the temperature through heat conduction. The gas cooling system cooperates with the uniform gas system to cool the silicon wafer substrate by spraying cooling gas on the surface of the silicon wafer substrate. The combination of the two can achieve 0-500℃ temperature control of the carrier, thereby controlling the temperature of the silicon wafer substrate.

[0062] The chamber structure has a vacuum reaction chamber, a feed chamber and a discharge chamber. The vacuum reaction chamber will maintain a high vacuum state (below 10Pa) for a long time except for maintenance, and external pollutants are prohibited from entering the vacuum reaction chamber to ensure the cleanliness of the coating environment and improve the film quality. The feed chamber is a transition chamber, one end of which is connected to the atmospheric environment and the other end is connected to the vacuum reaction chamber. Under the control of the automation system, the carrier will carry the silicon wafer substrate into the feed chamber in the atmospheric state, and then the automation system controls the pump group to vacuum the feed chamber. After the feed chamber reaches a high vacuum, the carrier enters the vacuum reaction chamber for thin film deposition. The discharge chamber is a transition chamber, which is connected to the vacuum reaction chamber and maintains a vacuum during the process. The deposited film can enter the discharge chamber. A pressure relief valve is provided on the discharge chamber, and the film can be taken out after the pressure is relieved.

[0063] The automation system is divided into two parts: software and hardware. The hardware consists of PLC and various sensors, pumps and transmission devices controlled by PLC. The software part is independently developed and can realize the functions of process control, recipe compilation, data monitoring and data analysis. The automation system is the control center of the whole set of equipment, and can automatically execute the entire process of substrate loading, coating process execution and substrate unloading according to the compiled recipe.

[0064] The above-mentioned HoFCVD equipment is used to prepare low-temperature silicon nitride film, and the process gas may include ammonia (NH3), hydrogen (H2), silane (SiH4) and nitrogen (N2). Among them, ammonia and nitrogen are used as nitrogen sources, and silane is used as a silicon source. In the specific embodiment of the present invention, according to the specific performance indicators of the silicon nitride film to be prepared and the requirements of other process parameters, ammonia or nitrogen can be selected to participate in the reaction alone, or the two gases can be introduced simultaneously according to a certain volume ratio (the volume ratio is any ratio between pure ammonia and pure nitrogen) according to actual needs. In addition, by accurately controlling the volume ratio of each process gas (for example, the volume ratio can be as follows: silane: ammonia is 1:1 to 1:50; silane: nitrogen is 1:1 to 1:50; silane: hydrogen is 1:1 to 1:50), the physical and chemical properties of the film can be effectively optimized to meet the special requirements under different application scenarios.

[0065] During the preparation process, the present invention can be automatically implemented by an automated system. A user can input a predetermined process formula through the interface of the automated system. After the automated system receives the formula information, the corresponding process is automatically executed, which mainly includes the following steps:

[0066] Wafer loading: Control the robot or corresponding device to accurately place the substrate on a dedicated carrier;

[0067] Carrier transfer and preheating: The loaded carrier is sent into the vacuum reaction chamber. At this stage, the carrier temperature can be precisely controlled according to the recipe parameters, so that it gradually rises to and stabilizes at the set target temperature value;

[0068] Gas introduction: When the carrier temperature reaches and maintains at the set target temperature, the gas homogenization system is started to introduce the required process gas into the vacuum reaction chamber through the pre-designed specific gas pipeline;

[0069] Hot wire temperature adjustment: According to the formula requirements, the temperature of the hot wire is dynamically adjusted to ensure that the reaction conditions meet expectations, thereby ensuring the quality and performance of the silicon nitride film.

[0070] In the above process, the process gas (including but not limited to ammonia, hydrogen, silane, nitrogen) is catalytically decomposed on the surface of the high-temperature hot wire to form active groups. These active groups then migrate from the surface of the hot wire to the surface of the substrate, where they undergo a chemical reaction and are finally deposited to form a silicon nitride film. This process mainly relies on the high temperature condition of the hot wire to promote the decomposition of the process gas, and there is no strict requirement for the substrate temperature. In other words, even if the substrate temperature is at room temperature or slightly above room temperature, the film can be deposited smoothly. In addition, through the carrier temperature control device, the specific operating temperature of the substrate can also be flexibly adjusted according to the experimental requirements to adapt to the different requirements of different substrate materials for the growth temperature, which greatly broadens the scope of application of the process. At the same time, there are no strict requirements for the gas pressure in the process, and the pressure can be regulated according to specific needs. Above 0Pa, film formation can be achieved. The preferred gas pressure is between 0-10Pa. Because the gas pressure is extremely low, the mean free path of the reactant molecules in the vacuum reaction chamber is large, and the collision probability is extremely low, so that dust-free can be achieved and the maintenance frequency of the equipment can be reduced.

[0071] In the above process, the volume ratio of each reaction gas or process gas can be finely controlled (for example, the volume ratio can be as follows: silane: ammonia is 1: 1 to 1: 50; silane: nitrogen is 1: 1 to 1: 50; silane: hydrogen is 1: 1 to 1: 50) to prepare a silicon nitride film with an adjustable refractive index between 1.6 and 2.6. These films not only have high conformality and excellent density, but also have a wide range of uses. They can be used as optical films to improve the optical properties of optoelectronic devices, and can also be used as effective gas barrier films and wear-resistant protective layers to improve the environmental stability and mechanical strength of the device. Therefore, the silicon nitride film preparation technology provided in the embodiment of the present invention can not only meet the current semiconductor industry's demand for high-performance thin film materials, but also provide strong technical support for future new photovoltaic cells and other high-end applications.

[0072] In the above process, in the hot wire chemical vapor deposition (HWCVD) technology, the decomposition process of the process gas on the hot wire surface can be divided into three main steps: adsorption, decomposition and detachment. The efficiency of these three steps is directly affected by the temperature of the hot wire. Specifically, different hot wire temperatures will result in different decomposition products of gas molecules, and will also change the degree to which these products detach from the hot wire surface.

[0073] In addition, when the hot wire is in a relatively low temperature state, the gas molecules and their decomposition products cannot completely detach from the hot wire surface, which will cause metal compounds to gradually accumulate on the hot wire surface. This accumulation will not only reduce the decomposition efficiency of the hot wire on the reaction gas, but also shorten the service life of the hot wire, thereby affecting the overall operation cycle of the equipment. Therefore, the present invention proposes to introduce hydrogen as a protective gas in the process gas. Due to its strong reducing properties, hydrogen can effectively inhibit the formation of metal compounds, thereby maintaining the cleanliness of the hot wire surface and improving the decomposition efficiency and stability of the hot wire; at the same time, hydrogen can also play a certain cleaning function on the vacuum reaction chamber, reducing the maintenance frequency of the vacuum reaction chamber. In this way, not only can the service life of the hot wire be extended, but also the service life of the equipment can be effectively extended, maintenance costs can be reduced, and production efficiency can be improved.

[0074] Therefore, by reasonably regulating the temperature of the hot wire and introducing hydrogen as a protective gas, the process of the present invention can improve the reliability and economy of the process while ensuring the deposition of the silicon nitride film.

[0075] It can be seen that the hot wire chemical vapor deposition technology is used in the embodiment of the present invention to prepare a low-temperature silicon nitride film, which can realize the preparation of a dense silicon nitride film when the temperature of the silicon wafer substrate is above room temperature. At the same time, through the temperature control system, the specific working temperature of the substrate can be flexibly adjusted according to the experimental requirements to adapt to the different requirements of different substrate materials for the growth temperature, and the substrate temperature will not exceed 200°C. Under the appropriate gas pressure, it is possible to produce a silicon nitride film deposited under the condition of maintaining a relatively low substrate temperature, which is beneficial to the manufacture of HBC cells and perovskite cells in the photovoltaic field. In addition, the structure of the gas homogenization system is designed in the device of the present invention, which can solve the problem of uncontrollable spontaneous reactions of multiple reaction gases or process gases before entering the vacuum reaction chamber.

[0076] 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.

[0077] The above is only an embodiment of the present application, and the embodiment enables those skilled in the art to understand and implement the present application. Various modifications to the 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 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 for preparing a low-temperature silicon nitride film, characterized in that: Using hot-wire chemical vapor deposition technology, including: Placing the substrate on a carrier and placing the carrier into a vacuum reaction chamber; Introducing required process gases into the vacuum reaction chamber, wherein the process gases include: any one or both of ammonia and nitrogen, hydrogen and silane; The temperature of the hot wire is dynamically adjusted to deposit the desired silicon nitride film on the substrate.

2. The method for preparing a low-temperature silicon nitride film according to claim 1, characterized in that: Also includes: The temperature of the carrier in the vacuum reaction chamber is controlled so that the temperature of the carrier gradually rises to the set value. After the temperature of the carrier reaches and is maintained at the set value, the required process gas is introduced into the vacuum reaction chamber, and the cooling gas is further sprayed onto the substrate surface, thereby jointly controlling the substrate temperature.

3. The method for preparing a low-temperature silicon nitride film according to claim 2, characterized in that: The substrate is a single crystal silicon wafer, the carrier temperature is controlled at 0-500°C, and the substrate temperature is controlled above room temperature and not exceeding 200°C.

4. The method for preparing a low-temperature silicon nitride film according to claim 1, characterized in that: The refractive index of the obtained silicon nitride film is 1.6-2.

6.

5. The method for preparing a low-temperature silicon nitride film according to claim 1, characterized in that: The vacuum degree of the vacuum reaction chamber is controlled at 0-10Pa.

6. A device for preparing a low-temperature silicon nitride film using the method for preparing a low-temperature silicon nitride film as described in any one of claims 1 to 5, characterized in that: The equipment uses hot wire chemical vapor deposition technology for coating, including: a conveying system configured to place the substrate on a carrier and convey the carrier into the vacuum reaction chamber; A gas homogenizing system, the gas homogenizing system is disposed in the vacuum reaction chamber and is configured to introduce required process gases into the vacuum reaction chamber, wherein the process gases include: any one or both of ammonia and nitrogen, hydrogen and silane; A reaction system, wherein the reaction system is disposed in a vacuum reaction chamber and configured to dynamically adjust the temperature of the hot wire; An automation system is communicatively connected with the conveying system, the gas homogenization system and the reaction system.

7. The device according to claim 6, characterized in that Also includes: A temperature control system is configured to control the temperature of the carrier and the temperature of the substrate, and the temperature control system is communicatively connected with the automation system.

8. The device according to claim 7, characterized in that The temperature control system includes a contact temperature control device and a gas cooling system. The contact temperature control device is in direct contact with the carrier to control the temperature of the carrier and thus the temperature of the substrate on the carrier. The gas cooling system cooperates with the gas homogenization system and further controls the substrate temperature by spraying cooling gas onto the substrate surface.

9. The device according to claim 6, characterized in that The gas homogenization system adopts a multi-partitioned independent gas transportation system, and each partition structure adopts independent gas pipelines for different gases. During the coating reaction, the gas homogenization system passes the process gas into the vacuum reaction chamber through the corresponding gas pipelines.

10. The device according to claim 6, characterized in that The automation system includes a hardware part and a software part. The hardware part includes a PLC and sensors, pump groups and transmission devices controlled by the PLC. The software part is configured to realize process flow control, recipe compilation, data monitoring and data analysis and is configured to automatically execute the entire process flow of substrate loading, coating process and substrate unloading according to the compiled recipe.

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