A new silicon nitride substrate strip and mount method

Abstract

The present application relates to the technical field of ceramic materials, in particular to a novel silicon nitride substrate glue removal and wafer mounting method, the present application vertically removes glue, that is, boron nitride supporting plates are placed on both sides in the vertical direction, the silicon nitride ceramic green wafer is vertically clamped between the two boron nitride supporting plates, and the boron nitride supporting plates and the silicon nitride ceramic green wafer are fixed by using bolts. The weight of this glue removal and wafer mounting method does not act on the interlayer, the difference between the green wafers is reduced, and the consistency of the green wafers after glue removal is good. At the same time, vertical glue removal, the wafer spacing can be adjusted by the tightness of the bolts, the number of layers can be greatly increased, and the production capacity of glue removal can be greatly increased. Through the regulation of the temperature, pressure and time of segmented glue removal, the green wafers can be tightly arranged, the organic matter can be completely removed as much as possible, the residual carbon content is small, the green wafers are not easy to deform and crack, and the prepared silicon nitride substrate has high thermal conductivity and three-point bending strength.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a novel method for mounting silicon nitride substrates. Background Technology

[0002] Silicon nitride is an inorganic compound with high thermal and chemical stability. It is a ceramic material composed of silicon and nitrogen, and its unique crystal structure endows it with excellent physical and chemical properties. Silicon nitride has a very high melting point and hardness, allowing it to maintain stability even under extreme temperatures and harsh environments. In the ceramics industry, silicon nitride is widely used in various fields, including electronics, optics, aerospace, and chemical engineering. Its excellent mechanical properties and chemical stability make it an ideal choice for manufacturing advanced electronic devices, high-temperature resistant materials, and corrosion-resistant components. The production processes of silicon nitride ceramics are becoming increasingly sophisticated, including advancements in silicon nitride powder synthesis and ceramic forming technologies, further improving the efficiency and performance of its preparation. This makes silicon nitride ceramics a promising candidate for both scientific research and industrial applications.

[0003] During the sintering process of silicon nitride, the green blank needs to be placed in a debinding furnace to remove organic additives. These additives undergo chemical reactions such as cracking, carbonization, and oxidation within the furnace, generating gases such as carbon dioxide. Currently, silicon nitride debinding mainly employs a "sandwich" structure, with a 4mm thick boron nitride permeable sintering plate at the bottom, having a porosity of approximately 29% and a density of approximately 1.55 g / cm³. 3 Neatly stacked silicon nitride green sheets, approximately 10-15 sheets in total, are placed on a boron nitride sintering plate. Finally, a 4mm silicon nitride permeable pressure plate is placed on top of the green sheets. This method has several drawbacks. First, due to gravity, the bottom green sheets experience greater pressure, causing the adhesive vapor to be trapped during the debinding process, making it difficult to completely expel. This limits the number of layers; after a certain number, the green sheets cannot completely remove the adhesive. Second, after debinding, the pressure difference between the upper and lower sheets results in different residual carbon contents, with the bottom green sheets having a higher residual carbon content. This leads to inconsistent color of the sintered substrate. Furthermore, under the influence of gravity, the asynchronous debinding rates of the upper and lower sheets cause a time difference in green sheet shrinkage, making the green sheets prone to warping, cracking, and other defects.

[0004] For example, patent document CN115745625A discloses a high thermal conductivity silicon nitride substrate and its preparation method. The substrate is made from cast silicon nitride green ceramic sheets through a debinding process and a sintering process. The debinding process is as follows: first, the debinding furnace is evacuated, and then the temperature is raised to 200℃, 350℃ and 550℃ in sequence. Then, protective gas is introduced into the debinding furnace until the pressure inside the furnace becomes 0.07-0.1 MPa. Then, the introduction of protective gas is stopped, and the temperature is maintained for 0.5 to 2 hours. After that, the furnace is cooled to obtain green ceramic sheets with a carbon atom percentage of 0.09-0.11%. However, these existing technologies have not solved the problem that the residual carbon content of the silicon nitride green sheets is different due to differences in gravity and pressure, and the sheets are prone to cracking.

[0005] Therefore, based on the relevant technologies mentioned above, there is an urgent need to develop a new method for mounting silicon nitride substrates. Summary of the Invention

[0006] In view of this, the purpose of this invention is to propose a novel silicon nitride substrate arrangement and assembly method, so as to provide a silicon nitride substrate arrangement and assembly method with high production capacity and less susceptibility to cracking.

[0007] To achieve the above objectives, the present invention provides a novel method for die bonding and mounting silicon nitride substrates.

[0008] A novel silicon nitride substrate mounting method includes the following steps:

[0009] Step S1. After silicon nitride powder is cast into silicon nitride ceramic blanks, boron nitride firing plates are placed on both sides in the vertical direction, and the silicon nitride ceramic blanks are stacked vertically between the two boron nitride firing plates. The boron nitride firing plates and silicon nitride ceramic blanks are fixed with bolts and placed in a crucible.

[0010] Step S2. Place the crucible containing the silicon nitride ceramic blank into the muffle furnace and perform segmented glue removal.

[0011] Preferably, the thickness of the silicon nitride ceramic blank in step S1 is 0.1-0.3 mm.

[0012] Preferably, the thickness of the boron nitride bearing plate in step S1 is 3-5 mm.

[0013] Preferably, the casting process in step S1 is as follows:

[0014] Silicon nitride powder, dispersant, sintering aid and ethanol are mixed and ball-milled once. Then plasticizer and binder are added and ball-milled a second time. The ball-milled slurry is filtered through a filter screen, and then defoamer is added. After vacuum centrifugation for 30-45 minutes, it is formed by scraping in a casting machine, dried and rolled up. After vacuum sealing and cold isostatic pressing, silicon nitride ceramic blanks are obtained.

[0015] Preferably, the mass ratio of the silicon nitride powder, dispersant, sintering aid, ethanol, plasticizer, binder and defoamer is 55-65:2-6:3-5:15-25:5-8:8-12:0.5-1.2.

[0016] Preferably, the conditions for the first ball milling are:

[0017] ZrO2 balls of 10mm and 5mm were selected as the milling media, with a mass ratio of 1:1, a rotation speed of 250-280rpm, and a milling time of 2-4h.

[0018] The conditions for the secondary ball milling are as follows:

[0019] ZrO2 balls of 10mm and 5mm were selected as the milling media, with a mass ratio of 1:1, a rotation speed of 250-280rpm, and a milling time of 3-8h.

[0020] Preferably, the dispersant is ammonium polyacrylate;

[0021] The sintering aid is obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 1-3:2-5;

[0022] The plasticizer is glycerin;

[0023] The adhesive is polyethylene glycol.

[0024] Preferably, the particle size of the sintering aid is 3-5 μm.

[0025] Preferably, the silicon nitride powder has a particle size of 0.3-0.8 μm.

[0026] Preferably, the segmented glue removal step in step S2 is as follows:

[0027] Step S201. First, in an atmosphere with a pressure of 0.1-0.3 MPa and an air flow rate of 200-400 L / min in a muffle furnace, the temperature is increased from room temperature to 600℃ at a heating rate of 0.5-0.8℃ / min.

[0028] Step S202. Maintain 600℃ for 2-5 hours in an atmosphere with a pressure of 0.1-0.3MPa and an air flow rate of 200-400L / min in a muffle furnace;

[0029] Step S203. In a muffle furnace atmosphere with a pressure of 0.1-0.3 MPa and a nitrogen flow rate of 100-300 L / min, the temperature is increased from 600℃ to 1100℃ at a heating rate of 0.5-0.8℃ / min.

[0030] Step S204. Under an atmosphere of 0.3-0.8 MPa pressure and 100-250 L / min nitrogen flow rate in a muffle furnace, the temperature is lowered to 120-150℃ for 10-15 hours.

[0031] Step S205. After cooling is complete, open the furnace door.

[0032] The beneficial effects of this invention are:

[0033] This invention provides a novel method for bonding and mounting silicon nitride substrates. This method employs vertical bonding, where boron nitride (BN) support plates are placed on both sides vertically. Silicon nitride ceramic blanks are stacked and vertically sandwiched between the two BN support plates, and bolts are used to secure the BN support plates and the silicon nitride ceramic blanks. This bonding and mounting method prevents weight from being applied between layers, reduces differences between blanks, and results in good uniformity of the green blanks after bonding. Furthermore, the vertical bonding allows for adjustable spacing between blanks via bolts, significantly increasing the number of stacked blanks and bonding capacity. By controlling the temperature, pressure, and time of segmented bonding, air bonding is used below 600℃, and nitrogen bonding is used above 600℃. A heat treatment is also performed at 600℃ to ensure tight bonding between blanks, completely removing organic matter, minimizing residual carbon, and reducing the likelihood of deformation and cracking. The resulting silicon nitride substrate exhibits high thermal conductivity and three-point bending strength. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram showing the arrangement of the silicon nitride ceramic blank and the boron nitride firing plate in Embodiment 1 of the present invention;

[0036] Figure 2 This is a schematic diagram showing the arrangement of the silicon nitride ceramic blank and the boron nitride firing plate in Embodiment 2 of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0038] The sources and properties of some of the raw materials used in this invention are as follows:

[0039] Ammonium polyacrylate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; yttrium oxide was purchased from Shandong Zibo Ruibokang Rare Earth Materials Co., Ltd.; magnesium oxide was purchased from Shanghai Dunhuang Chemical Plant Co., Ltd.; glycerol was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; polyethylene glycol was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; silicon nitride powder was purchased from Qinhuangdao Yinuo High-tech Materials Development Co., Ltd.; and the defoamer, model Z-502, was purchased from Shanghai Yuewan New Materials Co., Ltd.

[0040] Example 1: A novel silicon nitride substrate arrangement and mounting method, comprising the following steps:

[0041] S1. Mix 55g silicon nitride powder, 2g ammonium polyacrylate, 3g sintering aid, and 15g ethanol, and perform a first ball milling. Use 10mm and 5mm ZrO2 balls as the milling media, with a mass ratio of 1:1, at a rotation speed of 250 rpm for 2 hours. Then add 5g glycerol and 8g polyethylene glycol, and perform a second ball milling. Use 10mm and 5mm ZrO2 balls as the milling media, with a mass ratio of 1:1, at a rotation speed of 250 rpm for 2 hours. The ball milling process was carried out at 250 rpm for 3 hours. The slurry after ball milling was filtered through a filter screen, and 0.5 g of defoamer Z-502 was added. After vacuum centrifugation for 30 minutes, the slurry was formed by a scraper in a casting machine, dried, and wound up. After vacuum sealing and cold isostatic pressing, silicon nitride ceramic blanks were obtained. The sintering aid was obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 1:2. The particle size of the sintering aid was 3 μm, and the particle size of the silicon nitride powder was 0.3 μm.

[0042] S2. Place boron nitride firing plates on both sides vertically, and sandwich the silicon nitride ceramic blanks vertically between the two boron nitride firing plates. Fix the boron nitride firing plates and silicon nitride ceramic blanks with bolts, and place them in a crucible. The thickness of the silicon nitride ceramic blanks is 0.1 mm, and the thickness of the boron nitride firing plates is 3 mm.

[0043] S3. Place the crucible containing the silicon nitride ceramic blank into the muffle furnace and perform segmented glue removal;

[0044] S4. First, in an atmosphere with a pressure of 0.1 MPa and an air flow rate of 200 L / min in a muffle furnace, the temperature is increased from room temperature to 600℃ at a heating rate of 0.5℃ / min.

[0045] S5. Maintain at 600℃ for 2 hours in an atmosphere with a muffle furnace pressure of 0.1MPa and an air flow rate of 200L / min;

[0046] S6. In a muffle furnace atmosphere with a pressure of 0.1 MPa and a nitrogen flow rate of 100 L / min, the temperature is increased from 600℃ to 1100℃ at a heating rate of 0.5℃ / min.

[0047] S7. Under an atmosphere of 0.3 MPa pressure and 100 L / min nitrogen flow rate in a muffle furnace, the temperature is lowered to 120℃ for 10 hours.

[0048] S8. After cooling is complete, open the furnace door.

[0049] Example 2: A novel silicon nitride substrate arrangement and mounting method, comprising the following steps:

[0050] S1. Mix 58g silicon nitride powder, 3g ammonium polyacrylate, 3.5g sintering aid, and 18g ethanol, and perform a first ball milling, using 10mm and 5mm ZrO2 balls as the milling media in a 1:1 mass ratio, at a rotation speed of 260 rpm for 2.5 hours. Then add 6g glycerol and 9g polyethylene glycol, and perform a second ball milling, using 10mm and 5mm ZrO2 balls as the milling media in a 1:1 mass ratio. The ball milling process was carried out at a speed of 260 rpm for 4 hours. The slurry after ball milling was filtered through a filter screen, and then 0.6 g of defoamer Z-502 was added. After vacuum centrifugation for 32 minutes, the slurry was formed by a scraper in a casting machine, dried, and wound up. After vacuum sealing and cold isostatic pressing, silicon nitride ceramic blanks were obtained. The sintering aid was obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 1:2. The particle size of the sintering aid was 3 μm, and the particle size of the silicon nitride powder was 0.4 μm.

[0051] S2. Place boron nitride firing plates on both sides vertically, and sandwich the silicon nitride ceramic blanks vertically between the two boron nitride firing plates. Fix the boron nitride firing plates and silicon nitride ceramic blanks with bolts, and place them in a crucible. The thickness of the silicon nitride ceramic blanks is 0.1 mm, and the thickness of the boron nitride firing plates is 3.5 mm.

[0052] S3. Place the crucible containing the silicon nitride ceramic blank into the muffle furnace and perform segmented glue removal;

[0053] S4. First, in an atmosphere with a pressure of 0.1 MPa and an air flow rate of 250 L / min in a muffle furnace, the temperature is increased from room temperature to 600℃ at a heating rate of 0.6℃ / min.

[0054] S5. Maintain at 600℃ for 3 hours in an atmosphere with a muffle furnace pressure of 0.1MPa and an air flow rate of 250L / min;

[0055] S6. In a muffle furnace atmosphere with a pressure of 0.1 MPa and a nitrogen flow rate of 150 L / min, the temperature is increased from 600℃ to 1100℃ at a heating rate of 0.6℃ / min.

[0056] S7. Under an atmosphere of 0.4 MPa pressure and 120 L / min nitrogen flow rate in a muffle furnace, the temperature was lowered to 125℃ for 11 hours.

[0057] S8. After cooling is complete, open the furnace door.

[0058] Example 3: A novel silicon nitride substrate arrangement and mounting method, comprising the following steps:

[0059] S1. Mix 60g silicon nitride powder, 4g ammonium polyacrylate, 4g sintering aid, and 18g ethanol, and perform a first ball milling. Use 10mm and 5mm ZrO2 balls as the milling media, with a mass ratio of 1:1, at a rotation speed of 270 rpm for 3 hours. Then add 6.5g glycerol and 10g polyethylene glycol, and perform a second ball milling, using 10mm and 5mm ZrO2 balls as the milling media, with a mass ratio of 1:1, at a rotation speed of 270 rpm for 3 hours. The ball milling speed was 270 rpm, the ball milling time was 5 h, the ball milled slurry was filtered through a filter screen, and then 0.8 g of defoamer Z-502 was added for vacuum centrifugation degassing for 35 min. After that, it was formed by a scraper in a casting machine, dried and wound up, and then vacuum sealed and cold isostatically pressed to obtain silicon nitride ceramic blanks. The sintering aid was obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 2:3. The particle size of the sintering aid was 4 μm, and the particle size of the silicon nitride powder was 0.5 μm.

[0060] S2. Place boron nitride firing plates on both sides vertically, and sandwich the silicon nitride ceramic blanks vertically between the two boron nitride firing plates. Fix the boron nitride firing plates and silicon nitride ceramic blanks with bolts, and place them in a crucible. The thickness of the silicon nitride ceramic blanks is 0.2 mm, and the thickness of the boron nitride firing plates is 4 mm.

[0061] S3. Place the crucible containing the silicon nitride ceramic blank into the muffle furnace and perform segmented glue removal;

[0062] S4. First, in an atmosphere with a pressure of 0.2 MPa and an air flow rate of 300 L / min in a muffle furnace, the temperature is increased from room temperature to 600℃ at a heating rate of 0.7℃ / min.

[0063] S5. Maintain at 600℃ for 3 hours in an atmosphere with a muffle furnace pressure of 0.2MPa and an air flow rate of 300L / min;

[0064] S6. In a muffle furnace atmosphere with a pressure of 0.2 MPa and a nitrogen flow rate of 200 L / min, the temperature is increased from 600℃ to 1100℃ at a heating rate of 0.6℃ / min.

[0065] S7. Under an atmosphere of 0.5 MPa pressure and 180 L / min nitrogen flow rate in a muffle furnace, the temperature was lowered to 130℃ for 13 hours.

[0066] S8. After cooling is complete, open the furnace door.

[0067] Example 4: A novel silicon nitride substrate arrangement and mounting method, comprising the following steps:

[0068] S1. Mix 62g silicon nitride powder, 5g ammonium polyacrylate, 4.5g sintering aid, and 22g ethanol, and perform a first ball milling, using 10mm and 5mm ZrO2 balls as the milling media in a 1:1 mass ratio, at a rotation speed of 275 rpm for 3.5 hours. Then add 7g glycerol and 11g polyethylene glycol, and perform a second ball milling, using 10mm and 5mm ZrO2 balls as the milling media in a 1:1 mass ratio. The ball milling process was carried out at a speed of 275 rpm for 6 hours. The slurry after ball milling was filtered through a filter screen, and then 1g of defoamer Z-502 was added for vacuum centrifugation and degassing for 40 minutes. After that, it was formed by a scraper in a casting machine, dried, and wound up. Then, it was vacuum sealed and cold isostatically pressed to obtain silicon nitride ceramic blanks. The sintering aid was obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 2:4. The particle size of the sintering aid was 4.2 μm, and the particle size of the silicon nitride powder was 0.6 μm.

[0069] S2. Place boron nitride firing plates on both sides vertically, and sandwich the silicon nitride ceramic blanks vertically between the two boron nitride firing plates. Fix the boron nitride firing plates and silicon nitride ceramic blanks with bolts, and place them in a crucible. The thickness of the silicon nitride ceramic blanks is 0.3 mm, and the thickness of the boron nitride firing plates is 4 mm.

[0070] S3. Place the crucible containing the silicon nitride ceramic blank into the muffle furnace and perform segmented glue removal;

[0071] S4. First, in an atmosphere with a pressure of 0.3 MPa and an air flow rate of 350 L / min in a muffle furnace, the temperature is increased from room temperature to 600℃ at a heating rate of 0.7℃ / min.

[0072] S5. Maintain at 600℃ for 4 hours in an atmosphere with a muffle furnace pressure of 0.3MPa and an air flow rate of 350L / min;

[0073] S6. In a muffle furnace atmosphere with a pressure of 0.3 MPa and a nitrogen flow rate of 250 L / min, the temperature is increased from 600℃ to 1100℃ at a heating rate of 0.7℃ / min.

[0074] S7. Under an atmosphere of 0.6 MPa pressure and 220 L / min nitrogen flow rate in a muffle furnace, the temperature was lowered to 140℃ for 14 hours.

[0075] S8. After cooling is complete, open the furnace door.

[0076] Example 5: A novel silicon nitride substrate arrangement and mounting method, comprising the following steps:

[0077] S1. Mix 65g silicon nitride powder, 6g ammonium polyacrylate, 5g sintering aid, and 25g ethanol, and perform a first ball milling. Use 10mm and 5mm ZrO2 balls as the milling media, with a mass ratio of 1:1, at a rotation speed of 280 rpm for 4 hours. Then add 8g glycerol and 12g polyethylene glycol, and perform a second ball milling. Use 10mm and 5mm ZrO2 balls as the milling media, with a mass ratio of 1:1, at a rotation speed of 280 rpm for 4 hours. The ball milling process was carried out at 280 rpm for 8 hours. The slurry after ball milling was filtered through a filter screen, and then 1.2 g of defoamer Z-502 was added. After vacuum centrifugation for 45 min, the slurry was formed by a scraper in a casting machine, dried, and wound up. After vacuum sealing and cold isostatic pressing, silicon nitride ceramic blanks were obtained. The sintering aid was obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 3:5. The particle size of the sintering aid was 5 μm, and the particle size of the silicon nitride powder was 0.8 μm.

[0078] S2. Place boron nitride firing plates on both sides vertically, and sandwich the silicon nitride ceramic blanks vertically between the two boron nitride firing plates. Fix the boron nitride firing plates and silicon nitride ceramic blanks with bolts, and place them in a crucible. The thickness of the silicon nitride ceramic blanks is 0.3 mm, and the thickness of the boron nitride firing plates is 5 mm.

[0079] S3. Place the crucible containing the silicon nitride ceramic blank into the muffle furnace and perform segmented glue removal;

[0080] S4. First, in an atmosphere with a pressure of 0.3 MPa and an air flow rate of 400 L / min in a muffle furnace, the temperature is increased from room temperature to 600℃ at a heating rate of 0.8℃ / min.

[0081] S5. Maintain at 600℃ for 5 hours in an atmosphere with a muffle furnace pressure of 0.3MPa and an air flow rate of 400L / min;

[0082] S6. In a muffle furnace atmosphere with a pressure of 0.3 MPa and a nitrogen flow rate of 300 L / min, the temperature is increased from 600℃ to 1100℃ at a heating rate of 0.8℃ / min.

[0083] S7. Under an atmosphere of 0.8 MPa pressure and 250 L / min nitrogen flow rate in a muffle furnace, the temperature is reduced to 150℃ for 15 hours.

[0084] S8. After cooling is complete, open the furnace door.

[0085] Comparative Example 1:

[0086] Compared with Example 1, this comparative example only replaces "placing boron nitride firing plates on both sides in the vertical direction, vertically clamping the stacked silicon nitride ceramic blanks between the two boron nitride firing plates, and fixing the boron nitride firing plates and silicon nitride ceramic blanks with bolts" with "placing a boron nitride firing plate at the bottom, placing the stacked silicon nitride ceramic blanks on the boron nitride firing plate, and placing a boron nitride firing plate on top of the blanks". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a silicon nitride substrate is obtained.

[0087] Comparative Example 2:

[0088] Compared with Example 1, this comparative example only removes the step of "maintaining 600℃ for 2h in an atmosphere with a muffle furnace pressure of 0.1MPa and an air flow rate of 200L / min" in the segmented adhesive removal step. All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a silicon nitride substrate is obtained.

[0089] Comparative Example 3:

[0090] Compared with Example 1, this comparative example only replaces the segmented adhesive removal step with "heating from room temperature to 1100°C at a heating rate of 0.5°C / min in an atmosphere with a muffle furnace pressure of 0.1 MPa and an air flow rate of 200 L / min, and cooling down to 120°C in an atmosphere with a muffle furnace pressure of 0.3 MPa and a nitrogen flow rate of 100 L / min for 10 hours". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a silicon nitride substrate is obtained.

[0091] Comparative Example 4:

[0092] Compared with Example 1, this comparative example only replaces the phrase "cooling to 120°C for 10 hours in an atmosphere of 0.3 MPa pressure and 100 L / min nitrogen flow rate in the segmented adhesive removal step" with "cooling to 300°C for 10 hours in an atmosphere of 0.3 MPa pressure and 100 L / min nitrogen flow rate in the muffle furnace". All other steps and parameters are the same, and will not be repeated in this comparative example. The final silicon nitride substrate is obtained.

[0093] Comparative Example 5:

[0094] Compared with Example 1, this comparative example only replaces "the thickness of the silicon nitride ceramic blank is 0.1 mm" with "the thickness of the silicon nitride ceramic blank is 5 mm". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a silicon nitride substrate is obtained.

[0095] Performance testing:

[0096] Crack rate determination:

[0097] Silicon nitride ceramic blanks were mass-produced according to the methods in Examples 1-5 and Comparative Examples 1-5. After debinding, the silicon nitride ceramic blanks were sintered to obtain silicon nitride substrates, and their cracking rate was calculated.

[0098] Thermal conductivity measurement:

[0099] The thermal conductivity (W / (m·K)) of the silicon nitride substrates prepared in Examples 1-5 and Comparative Examples 1-5 was measured at room temperature using a laser pulse instrument.

[0100] Three-point bending strength test:

[0101] The three-point bending strength (MPa) of the silicon nitride substrates prepared in Examples 1-5 and Comparative Examples 1-5 of this invention was measured using the three-point bending method.

[0102] Table 1

[0103]

[0104]

[0105] Data Analysis:

[0106] As can be seen from Table 1, the silicon nitride substrate prepared by the present invention has high thermal conductivity and three-point bending strength, and is not easy to crack.

[0107] This may be because the present invention uses a vertical glue-dispensing and sheet-loading method, that is, boron nitride firing plates are placed on both sides in the vertical direction, and silicon nitride ceramic blanks are stacked vertically between the two boron nitride firing plates, and the boron nitride firing plates and silicon nitride ceramic blanks are fixed with bolts. Comparative Example 1 uses a traditional sandwich structure glue-dispensing and sheet-loading method, that is, a boron nitride firing plate is placed at the bottom, stacked silicon nitride ceramic blanks are placed on the boron nitride firing plate, and a boron nitride firing plate is placed on top of the blanks. When Example 1 and Comparative Example 1 are placed in crucibles of the same size for glue dispensing, it can be found that the vertical glue-dispensing and sheet-loading method in Example 1 can hold more silicon nitride ceramic blanks, such as... Figure 1 and Figure 2As shown, this increases the amount of adhesive removed from the furnace and expands production capacity. Traditional sandwich-structure adhesive removal and loading methods are easily affected by gravity, with the bottom blanks experiencing greater pressure. This causes adhesive vapors to be trapped during the removal process, making it difficult to completely expel them. This limits the number of layers; after a certain number of layers, the blanks cannot be completely cleaned of adhesive. Furthermore, after removal of adhesive from the upper and lower blanks, the pressure difference leads to different residual carbon contents, with the bottom blanks having a higher residual carbon content. This results in inconsistent color of the sintered substrate. Moreover, under the influence of gravity, the asynchronous removal rates of the upper and lower blanks cause a time difference in blank shrinkage, making the blanks prone to defects such as warping and cracking. Vertical adhesive removal, on the other hand, does not apply weight between layers, reducing differences between blanks and resulting in better consistency of the green blanks after removal. Additionally, with vertical adhesive removal, the spacing between blanks can be adjusted with bolts, significantly increasing the number of blanks per stack, thus greatly improving the production capacity of adhesive removal.

[0108] By controlling the temperature, pressure, and time of segmented debinding, air debinding is used below 600℃ and nitrogen debinding is used above 600℃. In addition, heat preservation treatment is carried out at 600℃. The blanks can be tightly packed, organic matter can be completely discharged as much as possible, the amount of residual carbon is small, and it is not easy to deform and crack. The resulting silicon nitride substrate has high thermal conductivity and three-point bending strength.

[0109] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0110] This 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 this invention should be included within the scope of protection of this invention.

Claims

1. A novel silicon nitride substrate arrangement and mounting method, characterized in that, Includes the following steps: Step S1. After silicon nitride powder is cast into silicon nitride ceramic blanks, boron nitride firing plates are placed on both sides in the vertical direction, and the silicon nitride ceramic blanks are stacked vertically between the two boron nitride firing plates. The boron nitride firing plates and silicon nitride ceramic blanks are fixed with bolts and placed in a crucible. Step S2. Place the crucible containing the silicon nitride ceramic blank into the muffle furnace and perform segmented glue removal; The casting process described in step S1 is as follows: Silicon nitride powder, dispersant, sintering aid and ethanol are mixed and ball-milled once. Then plasticizer and binder are added and ball-milled a second time. The ball-milled slurry is filtered through a filter screen, and defoamer is added. After vacuum centrifugation for 30-45 minutes, it is formed by scraping in a casting machine, dried and wound up. After vacuum sealing and cold isostatic pressing, silicon nitride ceramic blanks are obtained. The mass ratio of the silicon nitride powder, dispersant, sintering aid, ethanol, plasticizer, binder, and defoamer is 55-65: 2-6: 3-5: 15-25: 5-8: 8-12: 0.5-1.

2. The segmented glue removal process described in step S2 is as follows: Step S201. First, in an atmosphere with a pressure of 0.1-0.3 MPa and an air flow rate of 200-400 L / min in a muffle furnace, the temperature is increased from room temperature to 600℃ at a heating rate of 0.5-0.8℃ / min. Step S202. Maintain 600℃ for 2-5 hours in an atmosphere with a pressure of 0.1-0.3MPa and an air flow rate of 200-400L / min in a muffle furnace; Step S203. In a muffle furnace atmosphere with a pressure of 0.1-0.3 MPa and a nitrogen flow rate of 100-300 L / min, the temperature is increased from 600℃ to 1100℃ at a heating rate of 0.5-0.8℃ / min. Step S204. Under an atmosphere of 0.3-0.8 MPa pressure and 100-250 L / min nitrogen flow rate in a muffle furnace, the temperature is lowered to 120-150℃ for 10-15 hours. Step S205. After cooling is complete, open the furnace door.

2. The novel silicon nitride substrate arrangement and mounting method according to claim 1, characterized in that, The thickness of the silicon nitride ceramic blank in step S1 is 0.1-0.3 mm.

3. The novel silicon nitride substrate arrangement and mounting method according to claim 1, characterized in that, The thickness of the boron nitride bearing plate mentioned in step S1 is 3-5 mm.

4. The novel silicon nitride substrate arrangement and mounting method according to claim 1, characterized in that, The conditions for the first ball milling are as follows: ZrO2 balls of 10mm and 5mm were selected as the milling media, with a mass ratio of 1:1, a rotation speed of 250-280rpm, and a milling time of 2-4h. The conditions for the secondary ball milling are as follows: ZrO2 balls of 10mm and 5mm were selected as the milling media, with a mass ratio of 1:1, a rotation speed of 250-280rpm, and a milling time of 3-8h.

5. The novel silicon nitride substrate arrangement and mounting method according to claim 1, characterized in that, The dispersant is ammonium polyacrylate; The sintering aid is obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 1-3:2-5; The plasticizer is glycerin; The adhesive is polyethylene glycol.

6. The novel silicon nitride substrate arrangement and mounting method according to claim 1, characterized in that, The particle size of the sintering aid is 3-5 μm.

7. The novel silicon nitride substrate arrangement and mounting method according to claim 1, characterized in that, The silicon nitride powder has a particle size of 0.3-0.8 μm.

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