Ultra-large-size silicon device using diamond for heat dissipation and preparation method of ultra-large-size silicon device

Abstract

The invention provides an oversized diamond heat dissipation silicon device and a preparation method thereof. The preparation method comprises the following steps: cleaning and drying a monocrystalline silicon wafer under a room temperature condition; the method comprises the following steps: carrying out pretreatment seed crystal on a monocrystalline silicon wafer, covering a diamond nanocrystalline layer on the silicon surface, and putting the monocrystalline silicon wafer into MPCVD equipment; the cavity is vacuumized, then hydrogen is introduced for purging, and then the cavity is vacuumized again; then hydrogen is introduced, the air pressure is regulated and controlled to be 5-8 torr, and starting is started to ignite the plasma; the microwave power is increased to 70 KW to 75 KW at the speed of 4.5 KW / min to 5.5 KW / min, the air pressure is increased to 165 torr to 180 torr at the speed of 10 torr / min to 30 torr / min, and the temperature is increased to 900 DEG C to 950 DEG C at the speed of 55 DEG C / min to 65 DEG C / min; the flow of hydrogen ranges from 5000 sccm to 6000 sccm, the flow of methane ranges from 100 sccm to 150 sccm, the flow of oxygen ranges from 5 sccm to 8 sccm, the flow of nitrogen ranges from 1 sccm to 2 sccm, and the flow of argon ranges from 800 sccm to 1000 sccm; and after the growth is finished, cooling at the rate of 25-35 DEG C / min until the temperature is reduced to room temperature, introducing nitrogen into the cavity for vacuum breaking to obtain the oversized diamond polycrystalline film, and preparing the silicon device through film plating, copper plating and bonding. The silicon device is excellent in heat dissipation performance.

Description

Technical Field

[0001] The invention relates to an ultra-large silicon device using diamond for heat dissipation and a preparation method thereof, belonging to the technical field of semiconductor materials. Background Art

[0002] Silicon devices refer to semiconductor electronic devices made of silicon as the main material. As the requirements for performance and functionality of modern electronic devices continue to increase, the power density of silicon devices is also increasing. Under high power density, the heat generated per unit area or unit volume increases significantly. However, the thermal conductivity of silicon is relatively low, generally around 100-120W / (m·K), which means that the heat conduction speed inside the silicon device is slow, which is not conducive to the rapid dissipation of heat. When the silicon device is in a high-power working state, the heat generated is difficult to conduct quickly to the heat dissipation medium, which can easily cause the internal temperature of the silicon device to rise, affecting its performance and reliability.

[0003] Diamond has the highest thermal conductivity among known materials, up to 2200W / (m·K), far exceeding traditional heat dissipation materials such as copper and aluminum. If a diamond polycrystalline film can be grown on a silicon device, it will be able to quickly conduct the heat generated by the silicon device to ensure stable operation of the device, solving the problem of insufficient heat dissipation of traditional heat dissipation materials in high-power, high-frequency devices and greatly improving heat dissipation efficiency.

[0004] At present, the main method for growing diamond polycrystalline films is chemical vapor deposition (CVD) technology. Among them, microwave plasma assisted chemical vapor deposition (MPCVD) has become a common method for preparing high-quality diamond polycrystalline films because of its advantages such as no electrode pollution and the ability to accurately control reaction parameters. Through this technology, diamond polycrystalline films can be grown on substrate materials, providing a basis for achieving large-scale growth. However, the existing chemical vapor deposition (MPCVD) technology for growing diamond polycrystalline films has the following defects: (1) The current growth rate of diamond polycrystalline films is relatively low, especially for high-quality large-size films, which have a long growth cycle. This limits its large-scale production and application to a certain extent. The longer growth time will also increase production costs and reduce its market competitiveness; (2) Although diamond polycrystalline films of a certain size, such as two inches, can be prepared at present, compared with traditional semiconductor materials such as silicon wafers, their size is still relatively small, and it is difficult to meet the needs of large-size wafers for large-scale integrated circuits; (3) It is more difficult to achieve thickness uniformity and performance uniformity of diamond polycrystalline films within a large size range, which may lead to inconsistent performance in different areas on the same film, affecting its application effect in large-area devices.

[0005] In addition, during the preparation of silicon devices, diamond needs to be bonded to the bonding material. Due to the large size of large-size diamond polycrystalline films, there are problems such as stress, difficulty in alignment accuracy, poor uniformity, easy introduction of defects and impurities, and the warping between diamond and bonding materials causes excessive roughness, resulting in poor bonding quality and affecting the performance of silicon devices. Summary of the invention

[0006] The present invention provides an ultra-large silicon device using diamond for heat dissipation and a preparation method thereof, which can effectively solve the above problems.

[0007] The present invention is achieved in that:

[0008] A method for preparing an ultra-large silicon device using diamond for heat dissipation comprises the following steps:

[0009] S1, cleaning and drying the single crystal silicon wafer at room temperature;

[0010] S2, pre-treating the single crystal silicon wafer to form a seed crystal, so that the silicon surface is covered with a diamond nanocrystal layer, and placing it in an MPCVD device; the MPCVD device is a 915MHZ or 433MHZ MPCVD device;

[0011] S3, evacuate the chamber, then introduce hydrogen to purge, and then evacuate again; then introduce hydrogen and adjust the pressure to 5-8 torr to start igniting the plasma;

[0012] S4, increase the microwave power to 70-75KW at a rate of 4.5-5.5KW / min, increase the gas pressure to 165-180torr at a rate of 10-30torr / min, and increase the temperature to 900-950°C at a rate of 55-65°C / min;

[0013] S5, introducing growth gas: hydrogen flow rate 5000-6000sccm, methane flow rate 100-150sccm, oxygen flow rate 5-8sccm, nitrogen flow rate 1-2sccm, argon flow rate 800-1000sccm;

[0014] S6, after the growth is completed, the temperature is lowered at a rate of 30°C / min until it reaches room temperature, and then nitrogen is introduced into the chamber to break the vacuum, thereby obtaining an ultra-large-sized diamond polycrystalline film;

[0015] S7, grinding and polishing the silicon surface of the super-large-sized diamond polycrystalline film, removing part of the silicon base, and retaining the silicon base with a thickness of 50 nm to 50 μm;

[0016] S8, coating the silicon surface of the super-large-sized diamond polycrystalline film, wherein the coating material is one or more of titanium, chromium, and nickel;

[0017] S9, copper plating is performed on the silicon surface of the oversized diamond polycrystalline film after the coating is completed, and the copper plating thickness is 10nm to 2000nm;

[0018] S10, taking two copper-plated super-large-size diamond polycrystalline films, and cleaning and surface treating the copper surfaces of the two;

[0019] S11, copper-copper bonding is performed on the copper surfaces of the two, and the bonding steps are: copper-copper bonding is performed on the copper surfaces of the two, and the bonding steps are: room temperature alignment and pre-bonding are performed in the atmosphere, and then bonding is performed in a vacuum at a temperature of 180 to 220° C. and a pressure of 1.8 to 2.2 MPa for 25 to 35 minutes.

[0020] In some embodiments, the cleaning is to use acetone, alcohol, and deionized water to ultrasonically treat the single crystal silicon wafer for 15 to 30 minutes in sequence.

[0021] In some embodiments, the drying is to use an inert gas to blow dry the single crystal silicon wafer to dry its surface.

[0022] In some embodiments, the diamond nanocrystal layer has a thickness of 10 to 50 nm.

[0023] In some embodiments, the vacuum degree of the vacuum pumping is less than 5 mtorr, and the number of vacuum pumping is 3 to 5.

[0024] In some embodiments, the size of the oversized diamond polycrystalline film is 12 inches.

[0025] In some embodiments, the coating method is one of PVD, CVD, thermal evaporation, and electroplating.

[0026] In some embodiments, the copper plating method is one of electroplating, thermal evaporation, and magnetron sputtering.

[0027] In some embodiments, the surface treatment is surface cremation using Ar plasma or surface oxide cleaning using HCl.

[0028] An ultra-large silicon device using diamond for heat dissipation prepared by the method.

[0029] The beneficial effects of the present invention are:

[0030] The method of the present invention overcomes the problems of stress, difficulty in alignment accuracy, poor uniformity, easy introduction of defects and impurities, and excessive roughness caused by warping between diamond and bonding materials in large-sized diamond polycrystalline films through a specific process flow, and successfully prepares silicon devices on 12-inch ultra-large-sized diamond polycrystalline films with excellent heat dissipation performance.

[0031] The method of the present invention can grow a 12-inch polycrystalline diamond film through a specific process flow, which is much larger than the same size in the prior art, directly solving the problem of insufficient size, providing a basis for its application in large-area electronic devices, optical elements and other fields, making it more likely to be compatible with existing silicon-based semiconductor technology, and promoting the large-scale application of diamond films in related fields. With the expansion of production scale and the maturity of technology, it is expected to reduce the production cost per unit area to a certain extent. Thereby improving the competitiveness of large-size diamond polycrystalline films in the market and accelerating its industrialization process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 This is a size measurement diagram of the ultra-large-sized diamond polycrystalline film prepared in Example 1.

[0034] Figure 2 This is a thermal conductivity test diagram of the ultra-large-sized diamond polycrystalline film prepared in Example 1.

[0035] Figure 3 This is a flow chart of the method for preparing an ultra-large-sized silicon device using diamond for heat dissipation in Example 1.

[0036] Figure 4 This is a heat distribution diagram of the ultra-large-sized silicon device using diamond for heat dissipation prepared in Example 1.

[0037] Figure 5 This is the heat distribution diagram of the ultra-large-sized silicon device using diamond for heat dissipation prepared in Example 2.

[0038] Figure 6 This is the heat distribution diagram of the silicon device prepared in Comparative Example 1. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] An embodiment of the present invention provides a method for preparing an ultra-large silicon device using diamond for heat dissipation, the method comprising the following steps:

[0041] S1, at room temperature, the single crystal silicon wafer is first thoroughly cleaned and then dried. The purpose of this process is to ensure the cleanliness of the substrate to avoid contamination in the subsequent growth process.

[0042] S2, next, the single crystal silicon wafer is pre-treated and seeded to form a diamond nanocrystal seed layer on its surface. This seed layer will help to grow a high-quality polycrystalline diamond film in the future, and can ensure the uniform and high-quality growth of the diamond polycrystalline film. In this step, the seeded silicon wafer is placed in the MPCVD device to prepare for the growth of diamond polycrystalline film. The MPCVD device can be a quartz bell MPCVD, the microwave power supply can be a magnetron or a solid-state power supply, and the operating frequency can be 915MHz or 433MHz.

[0043] S3, then the chamber is evacuated, hydrogen is introduced for purging, and then evacuated again. The purpose of this series of operations is to clean the environment inside the chamber. Subsequently, hydrogen is introduced and the pressure is adjusted to 5-8 torr, and the plasma is started. In this step, the flow rate of hydrogen is set to 50 sccm.

[0044] S4, in the next experimental steps, the experimental parameters will be gradually adjusted to optimize the growth conditions of the diamond film. First, the microwave power will be gradually increased at a rate of 4.5 to 5.5 kilowatts (KW) per minute until it reaches a range of 70 to 75 kilowatts (KW). This process requires careful control to ensure a steady increase in microwave power to provide a uniform energy environment for the experiment. At the same time, the gas pressure will be gradually increased at a rate of 10 to 30 torr per minute until it reaches a range of 165 to 180 torr. The gradual increase in gas pressure helps maintain a stable state in the reaction chamber and ensures that the reactants are evenly distributed in the chamber.

[0045] In addition, the temperature needs to be gradually increased at a rate of 55 to 65 degrees Celsius (℃) per minute until it reaches 900 to 950 degrees Celsius (℃). This heating rate is crucial for the growth of diamond films because it ensures that the temperature reaches the required high temperature in a short time while avoiding damage to the experimental equipment due to sudden temperature changes. In this process, higher microwave power and lower gas pressure work together to significantly increase the volume of the plasma. The increase in plasma volume helps to cover a larger reaction area, thereby promoting the uniform growth of large-area diamond films.

[0046] In summary, microwave power, gas pressure and temperature increase rate have a decisive influence on the growth of large-area diamond films. By precisely controlling the adjustment rate of these parameters, the growth conditions of diamond films can be effectively optimized, thereby obtaining high-quality large-area diamond film products.

[0047] S5, after that, the growth gas is introduced, including hydrogen flow rate of 5000-6000sccm, methane flow rate of 100-150sccm, oxygen flow rate of 5-8sccm, nitrogen flow rate of 1-2sccm, and argon flow rate of 800-1000sccm. When the temperature rises to the rated temperature, the process gas flow rate is continuously increased from 0 over time within 10 minutes until the rated flow rate is reached, and then maintained for 5-10 minutes after reaching the rated flow rate. Among these gases, the larger hydrogen flow rate is to ensure that the gas flow can evenly fill the entire cavity. Methane is the main growth gas, while oxygen, nitrogen and argon are auxiliary growth gases. These parameters of the growth gas introduced are very critical to the growth quality of the diamond film. If they are not properly regulated, the thermal conductivity of the diamond film will be greatly reduced.

[0048] S6, when the growth process is completed, the temperature is lowered at a rate of 25-35°C / min until the temperature drops to room temperature. Subsequently, nitrogen is introduced into the cavity to break the vacuum, thereby obtaining the super-large-sized diamond polycrystalline film. After the cavity reaches normal temperature and pressure, the chamber can be opened to take out the silicon-based diamond polycrystalline film that has completed growth. By the method of the present invention, a super-large-sized diamond polycrystalline film with a size of up to 12 inches can be obtained, which is much larger than the size of similar diamond films in the prior art. The surface polycrystalline diamond is 1 to 500 microns thick.

[0049] S7, grinding and polishing the silicon surface of the oversized diamond polycrystalline film, removing part of the silicon base, and retaining the silicon base with a thickness of 50nm to 50μm; this step is to prepare for subsequent coating and bonding. Through this thinning process, the heat dissipation efficiency of the device can be significantly improved. Specifically, the thinned silicon base layer can conduct heat more effectively, thereby accelerating the speed at which heat is transferred from the inside of the device to the external environment. This improvement is particularly important for electronic devices that generate a lot of heat during operation, because it helps keep the device operating within a safe and efficient temperature range.

[0050] S8, coating the silicon surface of the super-large diamond polycrystalline film, the coating material is one or more of titanium, chromium, and nickel; the thickness of the film layer can be between 1 and 2000nm. The film layer acts as an intermediate layer between silicon and copper, and its purpose is to improve the bonding force, improve the interface reaction, and improve the stability. Through this coating process, the adhesion between the silicon-based material and the copper conductive layer can be effectively enhanced, thereby ensuring the stability and reliability of the conductive layer during the manufacturing process of electronic devices. In addition, this coating technology can also reduce the undesirable substances generated by the interface reaction, further improving the performance and life of electronic devices.

[0051] S9, copper plating is performed on the silicon surface of the oversized diamond polycrystalline film after the coating is completed, and the copper plating thickness is 10nm to 2000nm; thereby obtaining a material of diamond-silicon (after thinning)-thin film copper structure.

[0052] S10, taking two copper-plated super-large-size diamond polycrystalline films, and cleaning and surface treating the copper surfaces of the two;

[0053] S11, copper-copper bonding is performed on the copper surfaces of the two, which is wafer-to-wafer bonding. The bonding steps are: copper-copper bonding is performed on the copper surfaces of the two, and the bonding steps are: room temperature alignment and pre-bonding are performed in the atmosphere, and then bonding is performed in a vacuum at a temperature of 180 to 220° C. and a pressure of 1.8 to 2.2 MPa for 25 to 35 minutes.

[0054] The embodiment of the present invention performs film coating, copper plating, surface cleaning and surface treatment on the silicon surface of the ultra-large-sized diamond polycrystalline film, and solves the stress problems, difficult alignment accuracy, poor uniformity, easy introduction of defects and impurities, and the problem of excessive roughness caused by warping between diamond and bonding material on large-sized diamond through special bonding process steps, thereby improving the bonding quality and the performance of silicon devices.

[0055] In certain specific embodiments, the cleaning process includes ultrasonically cleaning the single crystal silicon wafer in sequence using acetone, alcohol and deionized water, and the ultrasonic time of each cleaning agent is set between 15 and 30 minutes. First, the single crystal silicon wafer is placed in acetone for ultrasonic cleaning to remove organic pollutants and grease on the surface. Then, the wafer is transferred to alcohol for a second ultrasonic cleaning to further remove residual organic matter and particles. Finally, the wafer is placed in deionized water for a third ultrasonic cleaning to remove residual alcohol and other possible impurities. Through this ultrasonic cleaning method using different cleaning agents in sequence, the cleanliness of the surface of the single crystal silicon wafer can be ensured, providing a clean substrate for subsequent process steps.

[0056] In some specific embodiments, the drying process can be achieved by using an inert gas to blow dry the single crystal silicon wafer, which can effectively remove moisture from the surface of the wafer to make it dry. Specifically, inert gases such as nitrogen or argon, etc., due to their stable chemical properties, will not react with the single crystal silicon wafer, so they can be safely used in the drying process. In this way, the dryness of the wafer surface can be ensured, thereby avoiding the adverse effects caused by moisture in the subsequent manufacturing process.

[0057] In some specific embodiments, the thickness of the diamond nanocrystalline layer is set between 10 nanometers and 50 nanometers. By accurately controlling this thickness range, the performance of the seed layer can be effectively ensured to be optimal. Such a seed layer thickness not only helps to achieve uniform growth of the polycrystalline diamond film, but also significantly improves its quality, ensuring that the grown diamond film has excellent physical and chemical properties. The selection of this thickness range is based on a deep understanding of the diamond growth mechanism and a detailed study of the interaction between the seed layer and the diamond film. By optimizing the thickness of the seed layer, defects that may occur during the growth process can be effectively avoided, thereby obtaining a high-quality polycrystalline diamond film.

[0058] In some specific embodiments, the vacuum degree of the evacuation is less than 5mtorr, that is, less than 5 millitorr (a unit of vacuum degree), and the number of evacuations is 3 to 5 times. The purpose of this process is to clean the environment in the cavity and ensure that there are no excess impurities and gas residues in the cavity. By evacuating the cavity multiple times, the pressure in the cavity can be effectively reduced, thereby achieving a highly clean and pure environment. Such an environment is crucial for the growth of polycrystalline diamond film because it helps to ensure that the polycrystalline diamond film can be grown under uniform and high-quality conditions. In this way, the quality and performance of the polycrystalline diamond film can be significantly improved, so that it exhibits better stability and reliability in various applications.

[0059] In some specific embodiments, after step S6, the process further includes: fine grinding and polishing the diamond surface of the aforementioned super-large-sized diamond polycrystalline film, in order to make its surface roughness reach a level of less than 1 nanometer (ra<1nm). Such treatment can significantly improve the surface quality of the diamond film, making it smoother, thereby meeting the requirements of certain high-precision applications.

[0060] Steps S1 to S6 of the embodiment of the present invention provide a method for preparing an ultra-large-sized diamond polycrystalline film. Through a unique process flow, the method successfully grows a polycrystalline diamond film with a diameter of 12 inches, which is far beyond the existing technology, directly overcomes the problem of size limitation, and lays the foundation for the application of diamond films in large-area electronic devices and optical components. This technology meets the heat dissipation needs of high-power density devices: as electronic devices develop towards miniaturization and high performance, the power density of devices such as chips continues to increase. Diamond heat sinks can effectively cope with the heat dissipation challenges under high power density, ensuring that the device can still maintain a low temperature when working under high load, thereby improving the performance and reliability of the device and extending its service life. For example, the power density of diamond heat sinks manufactured using chemical vapor deposition (CVD) technology is expected to be three times or more higher than the most advanced gallium nitride (GaN) devices currently available, and is particularly suitable for high-power, high-frequency switching application scenarios such as wireless communications and radar systems.

[0061] In addition, diamond heat dissipation technology can also optimize the performance and life of the chip. During the operation of the chip, excessively high temperature will lead to performance degradation, such as reduced carrier mobility, increased leakage current, reduced breakdown voltage, etc., and will also shorten the service life of the chip. Diamond heat dissipation can effectively control the temperature of the chip, reduce the performance degradation and shortened life caused by overheating, and ensure that the chip operates stably and efficiently under high frequency and high power conditions, giving full play to its performance advantages.

[0062] The high thermal conductivity of diamond also makes the design of the heat dissipation system simpler and more efficient. Compared with traditional heat dissipation solutions, the diamond heat dissipation system does not require complex heat dissipation structures and a large number of heat dissipation components, thereby reducing the volume, weight and cost of the heat dissipation system, while improving the integration and reliability of the entire system, helping to achieve miniaturization and lightweighting of electronic equipment.

[0063] Diamond heat sinks not only have good thermal conductivity, but also have excellent insulation properties, mechanical strength and thermal stability. They can maintain stable performance in harsh environments such as high temperature, high pressure, and high humidity, and are not prone to deformation, damage or performance degradation. Therefore, in fields such as aerospace, military equipment, and industrial control that require high environmental adaptability, diamond heat sinks can provide reliable heat dissipation for electronic devices and ensure the normal operation of equipment under extreme conditions.

[0064] Finally, diamond heat dissipation technology breaks through the limitations of traditional heat dissipation materials. Traditional heat dissipation materials such as copper and aluminum have certain limitations in terms of heat dissipation performance, physical properties or cost. For example, although copper has high thermal conductivity, it has high density, high cost, and may have electromagnetic compatibility issues in certain specific applications; aluminum has relatively weak heat dissipation performance and is difficult to meet the heat dissipation requirements of high-power devices. Diamond heat dissipation overcomes the shortcomings of these traditional materials and provides a more ideal solution to solve the heat dissipation problems of high-computing chips, high-frequency power devices, etc.

[0065] In some embodiments, the size of the oversized diamond polycrystalline film is 8-12 inches.

[0066] In some embodiments, the coating method is one of PVD, CVD, thermal evaporation, and electroplating.

[0067] In some embodiments, the copper plating method is one of electroplating, thermal evaporation, and magnetron sputtering.

[0068] In some embodiments, the surface treatment includes using argon plasma (Ar plasma) to perform surface cremation treatment, or using hydrochloric acid (HCl) to clean the surface oxide. The purpose of these treatment steps is to form active groups such as hydroxyl (OH) on the surface of the material. Such surface modification can significantly improve the activity of the material surface, thereby facilitating the subsequent bonding process.

[0069] An ultra-large silicon device using diamond for heat dissipation prepared by the method described. The silicon device of the embodiment of the present invention adopts steps S1 to S6 to prepare an ultra-large diamond polycrystalline film. Through a unique process flow, the method successfully grows a polycrystalline diamond film with a diameter of 12 inches, which is far beyond the existing technology, directly overcomes the problem of size limitation, and lays the foundation for the application of diamond film in large-area electronic devices and optical components. This technology meets the demand for heat dissipation of high-power density devices: as electronic equipment develops towards miniaturization and high performance, the power density of devices such as chips continues to increase. Diamond heat sinks can effectively cope with the heat dissipation challenges under high power density, ensuring that the device can still maintain a low temperature when working under high load, thereby improving the performance and reliability of the device and extending its service life. For example, the power density of diamond heat sinks manufactured using chemical vapor deposition (CVD) technology is expected to be three times or more higher than the most advanced gallium nitride (GaN) devices currently, and is particularly suitable for high-power, high-frequency switching application scenarios such as wireless communications and radar systems.

[0070] In addition, diamond heat dissipation technology can also optimize the performance and life of the chip. During the operation of the chip, excessively high temperature will lead to performance degradation, such as reduced carrier mobility, increased leakage current, reduced breakdown voltage, etc., and will also shorten the service life of the chip. Diamond heat dissipation can effectively control the temperature of the chip, reduce the performance degradation and shortened life caused by overheating, and ensure that the chip operates stably and efficiently under high frequency and high power conditions, giving full play to its performance advantages.

[0071] The high thermal conductivity of diamond also makes the design of the heat dissipation system simpler and more efficient. Compared with traditional heat dissipation solutions, the diamond heat dissipation system does not require complex heat dissipation structures and a large number of heat dissipation components, thereby reducing the volume, weight and cost of the heat dissipation system, while improving the integration and reliability of the entire system, helping to achieve miniaturization and lightweighting of electronic equipment.

[0072] Diamond heat sinks not only have good thermal conductivity, but also have excellent insulation properties, mechanical strength and thermal stability. They can maintain stable performance in harsh environments such as high temperature, high pressure, and high humidity, and are not prone to deformation, damage or performance degradation. Therefore, in fields such as aerospace, military equipment, and industrial control that require high environmental adaptability, diamond heat sinks can provide reliable heat dissipation for electronic devices and ensure the normal operation of equipment under extreme conditions.

[0073] Finally, diamond heat dissipation technology breaks through the limitations of traditional heat dissipation materials. Traditional heat dissipation materials such as copper and aluminum have certain limitations in terms of heat dissipation performance, physical properties or cost. For example, although copper has high thermal conductivity, it has high density, high cost, and may have electromagnetic compatibility issues in certain specific applications; aluminum has relatively weak heat dissipation performance and is difficult to meet the heat dissipation requirements of high-power devices. Diamond heat dissipation overcomes the shortcomings of these traditional materials and provides a more ideal solution to solve the heat dissipation problems of high-computing chips, high-frequency power devices, etc.

[0074] This silicon device will be widely used in high-power density chips including but not limited to GPU chips, AI chips, mobile phone chips, etc.

[0075] Example 1

[0076] A method for preparing an ultra-large silicon device using diamond for heat dissipation comprises the following steps:

[0077] S1, cleaning and drying the single crystal silicon wafer at room temperature; the cleaning is to use acetone, alcohol, and deionized water to ultrasonically treat the single crystal silicon wafer for 20 minutes in sequence. The drying is to use an inert gas to blow dry the single crystal silicon wafer to dry its surface.

[0078] S2, pre-treating the single crystal silicon wafer to make the silicon surface covered with a layer of diamond nanocrystal layer, and putting it into the MPCVD equipment (UP-575 high-power MPCVD equipment of Shenzhen Youpulai Plasma Technology Co., Ltd.) to prepare for the growth of diamond film; the thickness of the diamond nanocrystal layer is about 30nm.

[0079] S3, evacuate the cavity, then introduce hydrogen for purging, and then evacuate again; then introduce hydrogen and adjust the gas pressure to 6 torr to start igniting the plasma; the vacuum degree of the evacuation is less than 5 mtorr, and the number of evacuations is 3.

[0080] S4, increase the microwave power to 75 KW at a rate of 5 KW / min, increase the gas pressure to 170 torr at a rate of 15 torr / min, and increase the temperature to 920°C at a rate of 60°C / min.

[0081] S5, introduce growth gas: hydrogen flow rate 5500sccm, methane flow rate 125sccm, oxygen flow rate 6sccm, nitrogen flow rate 1.5sccm, argon flow rate 900sccm. When the temperature rises to the rated temperature, the process gas flow rate is continuously increased from 0 over time within 10 minutes until it reaches the rated flow rate, and then maintained for 8 minutes after reaching the rated flow rate.

[0082] S6, after the growth is completed, the temperature is lowered at a rate of 30°C / min until it reaches room temperature, and then nitrogen is introduced into the chamber to break the vacuum, thereby obtaining the ultra-large-sized diamond polycrystalline film. The surface polycrystalline diamond is 500 microns thick.

[0083] S7, grinding and polishing the silicon surface of the super-large-sized diamond polycrystalline film, removing part of the silicon base, and retaining the silicon base with a thickness of 20 μm;

[0084] S8, coating the silicon surface of the super-large-sized diamond polycrystalline film, the coating material is titanium, the thickness is 200 nm, and the coating method is PVD;

[0085] S9, copper plating is performed on the silicon surface of the oversized diamond polycrystalline film after the coating is completed, and the copper plating thickness is 1000nm; the copper plating method is electroplating.

[0086] S10, taking two copper-plated super-large-sized diamond polycrystalline films, and cleaning and surface treating the copper surfaces of the two films; the method is to use Ar plasma to perform surface cremation.

[0087] S11, copper-copper bonding is performed on the copper surfaces of the two, and the bonding steps are: copper-copper bonding is performed on the copper surfaces of the two, and the bonding steps are: room temperature alignment and pre-bonding are performed in the atmosphere, and then bonding is performed in a vacuum at a temperature of 200° C. and a pressure of 2 MPa for 30 minutes.

[0088] The size of the oversized diamond polycrystalline film in step S6 is measured, such as Figure 1 As shown. Figure 1 It can be seen that the size of the super-sized diamond polycrystalline film is about 12 inches (30.48 cm). The thermal conductivity of the super-sized diamond polycrystalline film in the test step S6 is 1993.2 W / (m·K) (e.g. Figure 2 The test method is 3ω electrical test technology, and the test temperature is 25℃±10℃.

[0089] Example 2

[0090] The surface polycrystalline diamond is 400 microns thick, and other operations are the same as in Example 1.

[0091] Comparative Example 1

[0092] Without preparing an ultra-large-sized diamond polycrystalline film, steps S1 to S6 are not performed, and steps S7 to S11 are performed directly on the silicon substrate. Other operations are the same as those in Example 1.

[0093] Comparative Example 2

[0094] The coating operation in step S8 is not performed, and other operations are the same as those in Example 1.

[0095] Comparative Example 3

[0096] The copper plating operation in step S9 is not performed, and other operations are the same as those in Example 1.

[0097] Comparative Example 4

[0098] The copper surface in step S10 is not cleaned or surface treated, and other operations are the same as those in embodiment 1.

[0099] Comparative Example 5

[0100] In step S11, the temperature is 300°C and the pressure is 5 MPa, and other operations are the same as those in Example 1.

[0101] Among them, Examples 1-2 and Comparative Example 1 were successfully bonded, while Comparative Examples 2-5 could not be effectively bonded.

[0102] According to the general simulation modeling method, detailed operation steps are performed, firstly, the power density parameters in the background environment are set, then the power density value of the hot spot area is accurately set, and then the heat distribution measurement experiment is performed on Example 1, Example 2 and Comparative Example 1 for comparison. The specific heat distribution results are shown in FIG. Figure 4-6 As shown, the figure clearly shows the heat distribution of each experimental sample.

[0103] Through careful analysis Figure 4-6 From the data, it can be clearly seen that the heat dissipation efficiency of the super-large silicon devices prepared in Examples 1 and 2 using diamond materials for heat dissipation is significantly higher than that of Comparative Example 1. This result shows that the use of diamond heat dissipation materials has significant advantages in improving the heat dissipation performance of silicon devices, and illustrates that the embodiments of the present invention solve the stress problems, alignment difficulties, poor uniformity, easy introduction of defects and impurities, and the problem of excessive roughness caused by warping between diamond and bonding materials, by coating and copper plating the silicon surface of the super-large diamond polycrystalline film, and by using characteristic bonding process steps, thereby improving the bonding quality and the performance of silicon devices.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an ultra-large silicon device using diamond for heat dissipation, characterized in that: The following steps are involved: S1, cleaning and drying the single crystal silicon wafer at room temperature; S2, pre-treating the single crystal silicon wafer to form a seed crystal, so that the silicon surface is covered with a diamond nanocrystalline layer, and placing it in an MPCVD device; the MPCVD device is a 915MHZ / 433MHZ MPCVD device; S3, evacuate the chamber, then introduce hydrogen to purge, and then evacuate again; then introduce hydrogen and adjust the pressure to 5-8 torr to start igniting the plasma; S4, increase the microwave power to 70-75KW at a rate of 4.5-5.5KW / min, increase the gas pressure to 165-180torr at a rate of 10-30torr / min, and increase the temperature to 900-950°C at a rate of 55-65°C / min; S5, introducing growth gas: hydrogen flow rate 5000-6000sccm, methane flow rate 100-150sccm, oxygen flow rate 5-8sccm, nitrogen flow rate 1-2sccm, argon flow rate 800-1000sccm; S6, after the growth is completed, the temperature is lowered at a rate of 25-35°C / min until it reaches room temperature, and then nitrogen is introduced into the chamber to break the vacuum, thereby obtaining an ultra-large-sized diamond polycrystalline film; S7, grinding and polishing the silicon surface of the super-large-sized diamond polycrystalline film, removing part of the silicon base, and retaining the silicon base with a thickness of 50 nm to 50 μm; S8, coating the silicon surface of the super-large-sized diamond polycrystalline film, wherein the coating material is one or more of titanium, chromium, and nickel; S9, copper plating is performed on the silicon surface of the oversized diamond polycrystalline film after the coating is completed, and the copper plating thickness is 10nm to 2000nm; S10, taking two copper-plated super-large-size diamond polycrystalline films, and cleaning and surface treating the copper surfaces of the two; S11, copper-copper bonding is performed on the copper surfaces of the two, and the bonding steps are: room temperature alignment and pre-bonding in the atmosphere, and then bonding in vacuum at a temperature of 180 to 220° C. and a pressure of 1.8 to 2.2 MPa for 25 to 35 minutes.

2. The method for preparing an ultra-large-sized silicon device using diamond for heat dissipation according to claim 1, characterized in that: The cleaning is to use acetone, alcohol and deionized water to ultrasonically clean the single crystal silicon wafer for 15 to 30 minutes in sequence.

3. The method for preparing an ultra-large-sized silicon device using diamond for heat dissipation according to claim 1, characterized in that: The drying is to use an inert gas to blow dry the single crystal silicon wafer to make its surface dry.

4. The method for preparing an ultra-large-sized silicon device using diamond for heat dissipation according to claim 1, characterized in that: The thickness of the diamond nanocrystal layer is 10-50 nm.

5. The method for preparing an ultra-large-sized silicon device using diamond for heat dissipation according to claim 1, characterized in that: The vacuum degree of the vacuum pumping is less than 5 mtorr, and the number of vacuum pumping is 3 to 5.

6. The method for preparing an ultra-large-sized silicon device using diamond for heat dissipation according to claim 1, characterized in that: The size of the super-large-sized diamond polycrystalline film is 12 inches.

7. The method for preparing an ultra-large-sized silicon device using diamond for heat dissipation according to claim 1, characterized in that: The coating method is one of PVD, CVD, thermal evaporation and electroplating.

8. The method for preparing an ultra-large-sized silicon device using diamond for heat dissipation according to claim 1, characterized in that: The copper plating method is one of electroplating, thermal evaporation and magnetron sputtering.

9. The method for preparing an ultra-large-sized silicon device using diamond for heat dissipation according to claim 1, characterized in that: The surface treatment is to use Ar plasma to perform surface cremation or to use HCl to clean the surface oxide.

10. An ultra-large silicon device using diamond for heat dissipation prepared by the method according to any one of claims 1 to 9.

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