A debinding process for high thermal conductivity silicon nitride substrate

Abstract

The invention relates to the technical field of silicon nitride material preparation, and in particular to a high thermal conductivity silicon nitride substrate debinding process. The invention comprises the following steps: firstly performing gradient heating debinding after vacuuming a debinding furnace, then charging a protective gas into the debinding furnace to make the pressure in the furnace reach 0.07-0.1Mpa, then sequentially performing ultra-high temperature treatment and temperature control and cooling treatment, and finally cooling the furnace to room temperature to obtain a silicon nitride green sheet; the gradient heating debinding comprises firstly heating the temperature to 150-200°C at 1-3°C / min and keeping the temperature for 0.5-1h, then heating the temperature to 300-350°C / min at 1-3°C / min and keeping the temperature for 1-2h, and finally heating the temperature to 550-600°C at 2-5°C / min and keeping the temperature for 1-2h; the ultra-high temperature treatment comprises heating the temperature to 1100-1150°C at 4-6°C / min and keeping the temperature for 2-6h; and the temperature control and cooling treatment comprises cooling the temperature to 150-200°C at 2-5°C / min. The present invention reduces the carbon atomic percentage of the silicon nitride green sheet to the greatest extent through the debinding process, thereby further improving the thermal conductivity of the silicon nitride substrate.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon nitride material preparation, and in particular to a high thermal conductivity silicon nitride substrate debinding process. Background Art

[0002] Silicon nitride is a high-performance semiconductor material with good thermal conductivity, electrical insulation, high temperature resistance and chemical stability. Therefore, it is widely used in heat dissipation devices in the fields of electronics, aerospace and automobiles. However, the preparation cost of silicon nitride is relatively high, mainly due to the high price of silicon nitride raw powder. In addition, the thermal conductivity of silicon nitride is also affected by its oxygen content. The higher the oxygen content, the worse the thermal conductivity.

[0003] There are currently two main methods for preparing silicon nitride: one is the high-temperature solid-phase reaction method, and the other is the chemical vapor deposition method. The high-temperature solid-phase reaction method is to react silicon powder and nitrogen at high temperature to generate silicon nitride. The advantage of this method is that the process is simple, but the energy consumption is high, and the purity of the obtained silicon nitride is not high; the chemical vapor deposition method is to deposit a silicon nitride film on the surface of the substrate through a chemical reaction. The advantage of this method is that the purity of the obtained silicon nitride is high, but the equipment is complex and the cost is high.

[0004] The existing silicon nitride preparation method has the following main problems: first, the preparation cost is high, mainly due to the high price of silicon nitride raw powder; second, the thermal conductivity of the obtained silicon nitride is affected by factors such as its oxygen content, making the thermal conductivity worse. Therefore, how to reduce its preparation cost and improve its thermal conductivity while ensuring the quality of silicon nitride is an important problem facing the current silicon nitride preparation technology. In order to solve this technical problem, those skilled in the art have proposed many solutions, such as a high thermal conductivity silicon nitride substrate and a preparation method thereof disclosed in patent technology document CN118439872B, which uses nano-carbon powder, nano-silicon dioxide, nano-magnesium oxide and nano-yttrium oxide as raw materials, and ball mills with solvents and hyperdispersants to obtain a suspension, and adds a binder and a plasticizer to the suspension, and performs secondary ball milling to obtain a slurry; then, a thin plate green body is obtained by a tape casting process, and then a binder is removed in a nitrogen atmosphere, and finally a gas pressure sintering process is used to obtain a silicon nitride substrate.

[0005] However, these prior art methods do not take into account the effects of processes such as debinding on the thermal conductivity of silicon nitride substrates. Debinding is the process of removing the organic binder in the green body. Because if these organic components are not removed, during the subsequent high-temperature sintering process, the binder will undergo reactions such as decomposition and carbonization, affecting the quality of the substrate. For example, defects such as pores and cracks may occur, thereby reducing many important properties of the silicon nitride substrate, such as thermal conductivity and mechanical properties. In summary, in the preparation process of high thermal conductivity silicon nitride substrates, it is also crucial whether the debinding process can discharge the carbon atoms produced by the carbonization of the organic binder in the green body to the greatest extent.

[0006] Therefore, according to the above-mentioned related technologies, it is urgent to develop a high thermal conductivity silicon nitride substrate debinding process. Summary of the invention

[0007] In view of this, the object of the present invention is to provide a debinding process for a high thermal conductivity silicon nitride substrate, so as to provide a debinding process to reduce the low carbon atomic percentage of the silicon nitride substrate, thereby improving its thermal conductivity.

[0008] Based on the above objectives, the present invention provides a high thermal conductivity silicon nitride substrate debinding process.

[0009] A high thermal conductivity silicon nitride substrate debinding process, the debinding process is as follows:

[0010] After the binder removal furnace is evacuated, a gradient temperature increase is performed to remove binders, and then a protective gas is filled into the binder removal furnace to make the pressure in the furnace reach 0.07-0.1Mpa, and then ultra-high temperature treatment and temperature control and cooling treatment are performed in sequence, and finally the furnace is cooled to room temperature to obtain a silicon nitride green sheet;

[0011] The gradient heating debinding process is to first heat the temperature to 150-200°C at 1-3°C / min and keep it for 0.5-1h, then heat the temperature to 300-350°C / min at 1-3°C / min and keep it for 1-2h, and finally heat the temperature to 550-600°C at 2-5°C / min for three times and keep it for 1-2h.

[0012] The ultra-high temperature treatment is to increase the temperature to 1100-1150°C at 4-6°C / min and keep the temperature for 2-6h;

[0013] The temperature control and cooling treatment is to cool the temperature to 150-200°C at 2-5°C / min.

[0014] Preferably, the vacuum degree in the debinding furnace after evacuation is 30-150 Pa.

[0015] Preferably, the protective gas is any one of nitrogen and argon.

[0016] Preferably, the preparation method of the high thermal conductivity silicon nitride substrate is as follows:

[0017] Step A1: mixing nano silicon nitride, nano yttrium oxide and a solvent and subjecting the mixture to ball milling, then adding a binder and a plasticizer and subjecting the mixture to secondary ball milling to obtain a slurry;

[0018] Step A2: the slurry is tape-casted and dried, and then subjected to a binder removal process to obtain a silicon nitride green sheet;

[0019] Step A3: placing the silicon nitride green sheet into a sintering furnace filled with protective gas for gas pressure sintering to obtain a silicon nitride substrate.

[0020] Preferably, the solvent in step A1 is any one or more of ethanol, xylene, and n-butanol.

[0021] Preferably, the binder in step A1 is a modified chlorinated polypropylene adhesive.

[0022] Preferably, the plasticizer in step A1 is butyl benzyl phthalate.

[0023] Preferably, the mass ratio of nano silicon nitride, nano yttrium oxide, solvent, binder and plasticizer in step A1 is 150-200:10-15:100-120:9-14:4-8.

[0024] Preferably, the protective gas in step A3 is any one of nitrogen and argon.

[0025] Preferably, the gas pressure during the gas pressure sintering treatment in step A3 is 0.07-0.1Mpa;

[0026] The gas pressure sintering treatment in step A3 is to first increase the temperature to 1750-1850° C. at a rate of 5-10° C. / min, keep the temperature for 2-8 hours, and then cool naturally to room temperature.

[0027] Beneficial effects of the present invention:

[0028] The present invention provides a high thermal conductivity silicon nitride substrate debinding process. The present invention first evacuates a debinding furnace and then performs gradient temperature debinding, so that the reaction is carried out in stages rather than simultaneously during the debinding process, thereby improving the uniformity of distribution of various components in the silicon nitride substrate and effectively reducing the carbon content; after that, a protective gas is filled into the debinding furnace to make the pressure in the furnace reach 0.07-0.1Mpa, so that the gas pressure drops suddenly in the phase change stage, promoting carbon and oxygen oxidation overflow, thereby achieving the purpose of reducing the oxygen atom content and carbon atom content in the silicon nitride substrate; and ultra-high temperature treatment and temperature control and cooling treatment further ensure the uniformity of distribution of various components in the silicon nitride substrate, and further reduce the carbon atom content, oxygen atom content and the possibility of cracking of the silicon nitride substrate; therefore, the high thermal conductivity silicon nitride substrate prepared by the debinding process of the present invention has lower oxygen atom content and carbon atom content, and higher thermal conductivity. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0030] The sources and properties of some of the raw materials used in the present invention are as follows:

[0031] Modified chlorinated polypropylene adhesive was purchased from Beijing Zhongke Optical Analysis Chemical Technology Research Institute; butyl benzyl phthalate was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; xylene was purchased from Shandong Zhengxing New Materials Co., Ltd.; and n-butanol was purchased from Jinan Yuanfei Weiye Chemical Co., Ltd.

[0032] Example 1: A high thermal conductivity silicon nitride substrate debonding process and a high thermal conductivity silicon nitride substrate preparation process are as follows:

[0033] S1: 150 g of nano silicon nitride, 10 g of nano yttrium oxide, and 100 g of ethanol were mixed and ball-milled, and then 9 g of modified chlorinated polypropylene adhesive and 4 g of butyl benzyl phthalate were added and ball-milled for a second time to obtain a slurry;

[0034] S2: The slurry is tape-casted, dried, and then subjected to a binder removal process to obtain a silicon nitride green sheet;

[0035] The debinding process is as follows: after vacuuming the debinding furnace, gradient heating debinding is first performed, then nitrogen is filled into the debinding furnace to make the pressure in the furnace reach 0.07Mpa, then ultra-high temperature treatment and temperature control and cooling treatment are performed in sequence, and finally the furnace is cooled to room temperature to obtain a silicon nitride green sheet;

[0036] The gradient heating debinding process is to first heat the temperature to 150°C at 1°C / min and keep it for 0.5h, then heat the temperature to 300°C / min at 1°C / min and keep it for 1h, and finally heat the temperature to 550°C at 2°C / min for three times and keep it for 1h.

[0037] The ultra-high temperature treatment is to increase the temperature to 1100°C at 4°C / min and keep the temperature for 2h;

[0038] The temperature control and cooling treatment is to cool the temperature to 150°C at 2°C / min;

[0039] The vacuum degree in the debinding furnace after evacuation is 30pa;

[0040] S3: placing the silicon nitride green sheet into a sintering furnace filled with nitrogen for gas pressure sintering to obtain a silicon nitride substrate;

[0041] The gas pressure during the gas pressure sintering process is 0.07Mpa;

[0042] The gas pressure sintering process is to first increase the temperature to 1750°C at a rate of 5°C / min, keep the temperature for 2 hours, and then naturally cool to room temperature;

[0043] Example 2: A high thermal conductivity silicon nitride substrate debinding process and a high thermal conductivity silicon nitride substrate preparation process are as follows:

[0044] S1: 160 g of nano silicon nitride, 11 g of nano yttrium oxide, and 105 g of xylene were mixed and ball-milled, and then 10 g of modified chlorinated polypropylene adhesive and 5 g of butyl benzyl phthalate were added and ball-milled for a second time to obtain a slurry;

[0045] S2: The slurry is tape-casted, dried, and then subjected to a binder removal process to obtain a silicon nitride green sheet;

[0046] The debinding process is as follows: after vacuuming the debinding furnace, gradient heating debinding is first performed, then nitrogen is filled into the debinding furnace to make the pressure in the furnace reach 0.08Mpa, then ultra-high temperature treatment and temperature control and cooling treatment are performed in sequence, and finally the furnace is cooled to room temperature to obtain a silicon nitride green sheet;

[0047] The gradient heating debinding method is to first heat the temperature to 160°C at 2°C / min and keep it for 0.6h, then heat the temperature to 310°C / min at 2°C / min and keep it for 1.2h, and finally heat the temperature to 560°C at 3°C / min for three times and keep it for 1.2h.

[0048] The ultra-high temperature treatment is to increase the temperature to 1110°C at 5°C / min and keep the temperature for 3h;

[0049] The temperature control and cooling treatment is to cool the temperature to 160°C at 3°C / min;

[0050] The vacuum degree in the debinding furnace after evacuation is 60pa;

[0051] S3: placing the silicon nitride green sheet into a sintering furnace filled with nitrogen for gas pressure sintering to obtain a silicon nitride substrate;

[0052] The gas pressure during the gas pressure sintering process is 0.08Mpa;

[0053] The gas pressure sintering treatment is to first increase the temperature to 1760°C at a rate of 6°C / min, keep the temperature for 3 hours, and then naturally cool to room temperature;

[0054] Example 3: A high thermal conductivity silicon nitride substrate debinding process and a high thermal conductivity silicon nitride substrate preparation process are as follows:

[0055] S1: 170 g of nano silicon nitride, 12 g of nano yttrium oxide, and 110 g of n-butanol were mixed and ball-milled, and then 11 g of modified chlorinated polypropylene adhesive and 6 g of butyl benzyl phthalate were added and ball-milled for a second time to obtain a slurry;

[0056] S2: The slurry is tape-casted, dried, and then subjected to a binder removal process to obtain a silicon nitride green sheet;

[0057] The debinding process is as follows: after vacuuming the debinding furnace, gradient heating debinding is first performed, then argon is filled into the debinding furnace to make the pressure in the furnace reach 0.09 MPa, then ultra-high temperature treatment and temperature control and cooling treatment are performed in sequence, and finally the furnace is cooled to room temperature to obtain a silicon nitride green sheet;

[0058] The gradient heating debinding method is to first heat the temperature to 170°C at 2°C / min and keep it for 0.7h, then heat the temperature to 320°C / min at 2°C / min and keep it for 1.5h, and finally heat the temperature to 570°C at 4°C / min for three times and keep it for 1.5h.

[0059] The ultra-high temperature treatment is to increase the temperature to 1130°C at 5°C / min and keep the temperature for 4 hours;

[0060] The temperature control and cooling treatment is to cool the temperature to 170°C at 4°C / min;

[0061] The vacuum degree in the debinding furnace after evacuation is 90pa;

[0062] S3: placing the silicon nitride green sheet into a sintering furnace filled with argon gas for gas pressure sintering to obtain a silicon nitride substrate;

[0063] The gas pressure during the gas pressure sintering process is 0.08Mpa;

[0064] The gas pressure sintering treatment is to first increase the temperature to 1770°C at a rate of 7°C / min, keep the temperature for 5 hours, and then naturally cool to room temperature;

[0065] Example 4: A high thermal conductivity silicon nitride substrate debonding process and a high thermal conductivity silicon nitride substrate preparation process are as follows:

[0066] S1: 190 g of nano silicon nitride, 13 g of nano yttrium oxide, 100 g of ethanol, and 15 g of xylene were mixed and ball-milled, and then 12 g of modified chlorinated polypropylene adhesive and 7 g of butyl benzyl phthalate were added and ball-milled for a second time to obtain a slurry;

[0067] S2: The slurry is tape-casted, dried, and then subjected to a binder removal process to obtain a silicon nitride green sheet;

[0068] The debinding process is as follows: after vacuuming the debinding furnace, gradient heating debinding is first performed, then argon is filled into the debinding furnace to make the pressure in the furnace reach 0.09 MPa, then ultra-high temperature treatment and temperature control and cooling treatment are performed in sequence, and finally the furnace is cooled to room temperature to obtain a silicon nitride green sheet;

[0069] The gradient heating debinding method is to first heat the temperature to 190°C at 2°C / min and keep it for 0.9h, then heat the temperature to 340°C / min at 2°C / min and keep it for 1.8h, and finally heat the temperature to 590°C at 4°C / min for three times and keep it for 1.8h.

[0070] The ultra-high temperature treatment is to increase the temperature to 1140°C at 5°C / min and keep the temperature for 5 hours;

[0071] The temperature control and cooling treatment is to cool the temperature to 190°C at 4°C / min;

[0072] The vacuum degree in the debinding furnace after evacuation is 120pa;

[0073] S3: placing the silicon nitride green sheet into a sintering furnace filled with argon gas for gas pressure sintering to obtain a silicon nitride substrate;

[0074] The gas pressure during the gas pressure sintering process is 0.09Mpa;

[0075] The gas pressure sintering treatment is to first increase the temperature to 1800°C at a rate of 9°C / min, keep the temperature for 6 hours, and then naturally cool to room temperature;

[0076] Example 5: A high thermal conductivity silicon nitride substrate debonding process and a high thermal conductivity silicon nitride substrate preparation process are as follows:

[0077] S1: 200 g of nano silicon nitride, 15 g of nano yttrium oxide, 100 g of ethanol, and 20 g of n-butanol were mixed and ball-milled, and then 14 g of modified chlorinated polypropylene adhesive and 8 g of butyl benzyl phthalate were added, and ball-milled for a second time to obtain a slurry;

[0078] S2: The slurry is tape-casted, dried, and then subjected to a binder removal process to obtain a silicon nitride green sheet;

[0079] The debinding process is as follows: after vacuuming the debinding furnace, gradient heating debinding is first performed, then argon is filled into the debinding furnace to make the pressure in the furnace reach 0.1Mpa, then ultra-high temperature treatment and temperature control and cooling treatment are performed in sequence, and finally the furnace is cooled to room temperature to obtain a silicon nitride green sheet;

[0080] The gradient heating debinding process is to first heat the temperature to 200°C at 3°C / min and keep it for 1 hour, then heat the temperature to 350°C / min at 3°C / min and keep it for 2 hours, and finally heat the temperature to 600°C at 5°C / min for three times and keep it for 2 hours.

[0081] The ultra-high temperature treatment is to increase the temperature to 1150°C at 6°C / min and keep the temperature for 6 hours;

[0082] The temperature control and cooling treatment is to cool the temperature to 200°C at 5°C / min;

[0083] The vacuum degree in the debinding furnace after evacuation is 150 Pa;

[0084] S3: placing the silicon nitride green sheet into a sintering furnace filled with argon gas for gas pressure sintering to obtain a silicon nitride substrate;

[0085] The gas pressure during the gas pressure sintering process is 0.1Mpa;

[0086] The gas pressure sintering treatment is to first increase the temperature to 1850°C at a rate of 10°C / min, keep the temperature for 8 hours, and then naturally cool to room temperature;

[0087] Comparative Example 1:

[0088] Compared with Example 1, this comparative example only replaces the following steps in the gradient heating debinding process: "first heating to 150°C at 1°C / min once and keeping warm for 0.5h, then heating to 300°C / min twice at 1°C / min and keeping warm for 1h, and finally heating to 550°C three times at 2°C / min and keeping warm for 1h" with "first heating to 150°C at 1°C / min once, then heating to 300°C / min twice at 0.5°C / min and keeping warm for 2h, and finally heating to 550°C three times at 2°C / min and keeping warm for 1h". The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a high thermal conductivity silicon nitride substrate is obtained.

[0089] Comparative Example 2:

[0090] Compared with Example 1, this comparative example only replaces the following steps in the gradient heating debinding process: "first heating to 150°C at 1°C / min once and keeping warm for 0.5h, then heating to 300°C / min at 1°C / min twice and keeping warm for 1h, and finally heating to 550°C at 2°C / min three times and keeping warm for 1h" with "first heating to 300°C / min at 1°C / min once and keeping warm for 2h, and finally heating to 550°C at 2°C / min twice and keeping warm for 1h", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a high thermal conductivity silicon nitride substrate is obtained;

[0091] Comparative Example 3:

[0092] Compared with Example 1, this comparative example only replaces the following steps in the gradient heating debinding process: "first heating to 150°C at 1°C / min and keeping warm for 0.5h, then heating to 300°C / min at 1°C / min and keeping warm for 1h, and finally heating to 550°C at 2°C / min and keeping warm for 1h" with "heating to 550°C at 2°C / min and keeping warm for 3h", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a high thermal conductivity silicon nitride substrate is obtained;

[0093] Comparative Example 4:

[0094] Compared with Example 1, this comparative example does not perform ultra-high temperature treatment during the preparation of the silicon nitride green sheet, and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a high thermal conductivity silicon nitride substrate is obtained;

[0095] Comparative Example 5:

[0096] Compared with Example 1, this comparative example only replaces "cooling to 150°C at 2°C / min" in the temperature control and cooling process with "cooling to 300°C at 2°C / min", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a high thermal conductivity silicon nitride substrate is obtained.

[0097] Performance Test:

[0098] Determination of C content:

[0099] The carbon atom content (%) of the high thermal conductivity silicon nitride substrates prepared in Examples 1 to 5 and Comparative Examples 1 to 5 of the present invention was measured by chemical titration. The measurement results are shown in Table 1.

[0100] Determination of O content:

[0101] The oxygen atomic content (%) of the high thermal conductivity silicon nitride substrates prepared in Examples 1 to 5 of the present invention and Comparative Examples 1 to 5 was measured, and the measurement results are shown in Table 1;

[0102] Determination of thermal conductivity:

[0103] The thermal conductivity w / (m·k) of the high thermal conductivity silicon nitride substrates prepared in Examples 1 to 5 and Comparative Examples 1 to 5 of the present invention was measured at 25° C. using a laser pulse instrument. The measurement results are shown in Table 1.

[0104] Determination of flexural strength:

[0105] The three-point bending method was used to test the flexural strength. The span was 30 mm and the loading rate of the pressure head was 0.5 mm / min. The flexural strength (Mpa) of the high thermal conductivity silicon nitride substrates prepared in Examples 1 to 5 and Comparative Examples 1 to 5 of the present invention was measured according to this method. The measurement results are shown in Table 1.

[0106] Table 1

[0107]

[0108] Data Analysis:

[0109] As can be seen from Table 1, the high thermal conductivity silicon nitride substrate prepared by the debinding process of the present invention has lower oxygen atom content and carbon atom content, as well as higher thermal conductivity and flexural strength;

[0110] This may be because the debinding process of the present invention first evacuates the debinding furnace and then performs gradient temperature debinding, which can make the reaction proceed in stages rather than simultaneously during the debinding process, thereby improving the uniformity of distribution of the components in the silicon nitride substrate while effectively reducing the porosity and carbon content; after the combination, the protective gas is filled into the debinding furnace to make the pressure in the furnace reach 0.07-0.1Mpa, so that the gas pressure drops suddenly during the phase change stage, promoting carbon and oxygen oxidation overflow, thereby achieving the purpose of reducing the oxygen atom content and carbon atom content in the silicon nitride substrate; and the ultra-high temperature treatment and temperature control and cooling treatment ensure that the binder and other components in the green body can be completely reacted, and further ensure the uniformity of distribution of the components in the silicon nitride substrate, and further reduce the carbon atom content, oxygen atom content and the possibility of cracking of the silicon nitride substrate; therefore, the high thermal conductivity silicon nitride substrate prepared by the debinding process of the present invention has lower oxygen atom content and carbon atom content, as well as higher thermal conductivity and bending strength.

[0111] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0112] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high thermal conductivity silicon nitride substrate debinding process, characterized in that: The debinding process is as follows: After the binder removal furnace is evacuated, a gradient temperature increase is performed to remove binders, and then a protective gas is filled into the binder removal furnace to make the pressure in the furnace reach 0.07-0.1Mpa, and then ultra-high temperature treatment and temperature control and cooling treatment are performed in sequence, and finally the furnace is cooled to room temperature to obtain a silicon nitride green sheet; The gradient heating debinding process is to first heat the temperature to 150-200°C at 1-3°C / min and keep it for 0.5-1h, then heat the temperature to 300-350°C / min at 1-3°C / min and keep it for 1-2h, and finally heat the temperature to 550-600°C at 2-5°C / min for three times and keep it for 1-2h. The ultra-high temperature treatment is to increase the temperature to 1100-1150°C at 4-6°C / min and keep the temperature for 2-6h; The temperature control and cooling treatment is to cool the temperature to 150-200°C at 2-5°C / min.

2. The high thermal conductivity silicon nitride substrate debinding process according to claim 1, characterized in that: The vacuum degree in the debinding furnace after evacuation is 30-150 Pa.

3. The high thermal conductivity silicon nitride substrate debinding process according to claim 1, characterized in that: The protective gas is any one of nitrogen and argon.

4. The high thermal conductivity silicon nitride substrate debinding process according to claim 1, characterized in that: The preparation method of the high thermal conductivity silicon nitride substrate is as follows: Step A1: mixing nano silicon nitride, nano yttrium oxide and a solvent and subjecting the mixture to ball milling, then adding a binder and a plasticizer and subjecting the mixture to secondary ball milling to obtain a slurry; Step A2: the slurry is tape-casted and dried, and then subjected to a binder removal process to obtain a silicon nitride green sheet; Step A3: placing the silicon nitride green sheet into a sintering furnace filled with protective gas for gas pressure sintering to obtain a silicon nitride substrate.

5. The high thermal conductivity silicon nitride substrate debinding process according to claim 4, characterized in that: The solvent in step A1 is any one or more of ethanol, xylene, and n-butanol.

6. The high thermal conductivity silicon nitride substrate debinding process according to claim 4, characterized in that: The adhesive in step A1 is a modified chlorinated polypropylene adhesive.

7. The high thermal conductivity silicon nitride substrate debinding process according to claim 4, characterized in that: The plasticizer in step A1 is butyl benzyl phthalate.

8. The high thermal conductivity silicon nitride substrate debinding process according to claim 4, characterized in that: The mass ratio of nano silicon nitride, nano yttrium oxide, solvent, binder and plasticizer in step A1 is 150-200: 10-15: 100-120: 9-14: 4-8.

9. The high thermal conductivity silicon nitride substrate debinding process according to claim 4, characterized in that: The protective gas in step A3 is any one of nitrogen and argon.

10. The high thermal conductivity silicon nitride substrate debinding process according to claim 4, characterized in that: The gas pressure during the gas pressure sintering process in step A3 is 0.07-0.1Mpa; The gas pressure sintering treatment in step A3 is to first increase the temperature to 1750-1850° C. at a rate of 5-10° C. / min, keep the temperature for 2-8 hours, and then cool naturally to room temperature.

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