Novel silicon nitride substrate glue discharging and chip mounting mode

Abstract

The invention relates to the technical field of ceramic materials, in particular to a novel silicon nitride substrate glue discharging and loading mode, which comprises the following steps of: vertically discharging glue, namely placing boron nitride setter plates on two sides in the vertical direction, vertically clamping a silicon nitride ceramic blank sheet lamination between the two boron nitride setter plates, and loading the silicon nitride ceramic blank sheet lamination between the two boron nitride setter plates; bolts are used for fixing the boron nitride burning bearing plate and the silicon nitride ceramic blank pieces, the weight cannot act on the layers in the glue discharging and piece loading mode, the difference between the blank pieces is reduced, and the consistency of the green blank pieces obtained after glue discharging is good. Meanwhile, vertical glue discharging is achieved, the tightness of the distance between the sheets can be adjusted through bolts, the number of the laminated sheets can be greatly increased, and the glue discharging capacity can be greatly improved. By regulating and controlling the temperature, the pressure and the time of segmented glue discharging, the blank sheets can be tightly arranged, organic matters can be completely discharged as far as possible, the carbon residue amount is small, deformation and cracking are not prone to occurring, and the prepared silicon nitride substrate has high heat conductivity and three-point bending strength.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic materials, and in particular to a novel silicon nitride substrate debonding and mounting method. Background Art

[0002] Silicon nitride is an inorganic compound with high thermal and chemical stability. It is a ceramic material composed of silicon and nitrogen elements, and its special crystal structure gives it excellent physical and chemical properties. Silicon nitride has a very high melting point and hardness, which enables it to remain stable under extremely high temperatures and harsh environments. In the ceramic industry, silicon nitride is widely used in various fields, including electronics, optics, aerospace, and chemical industry. Its excellent mechanical properties and chemical stability make it an ideal choice for the preparation of advanced electronic devices, high-temperature resistant materials, and corrosion-resistant components. The production process of silicon nitride ceramics is becoming increasingly perfect, including the synthesis of silicon nitride powder and the development of ceramic forming technology, which further improves the efficiency and performance of its preparation, which makes silicon nitride ceramics have broad prospects in scientific research and industrial applications.

[0003] During the sintering process of silicon nitride, the green body needs to be placed in a debinding furnace to remove the organic additives. These additives will undergo chemical reactions such as cracking, carbonization and oxidation in the furnace, and produce gases such as carbon dioxide. At present, the debinding of silicon nitride mainly adopts a "sandwich" structure, with a 4mm thick boron nitride breathable support plate placed at the bottom, with a porosity of about 29% and a density of about 1.55g / cm 3 , place neatly stacked silicon nitride green sheets on the boron nitride support plate, the number is about 10-15 sheets. Finally, place a 4mm silicon nitride breathable pressure plate on the top of the green sheet. This method has several defects. One is that due to the influence of gravity, the green sheet at the bottom is subjected to greater pressure, resulting in the colloidal vapor being suppressed during the debinding process, making it difficult to completely discharge, resulting in an upper limit on the number of layers. After reaching a certain number of layers, the green sheet cannot completely drain the colloidal material. At the same time, after the upper and lower sheets are debinded, the residual carbon content is different due to the pressure difference, and the remaining carbon content of the green sheet at the bottom is higher. As a result, the color of the substrate after sintering is inconsistent. Moreover, under the influence of gravity, the debinding rates of the upper and lower sheets are not synchronized, resulting in a time difference in the shrinkage of the green body, which makes the green sheet prone to defects such as warping and cracking.

[0004] For example, patent document CN115745625A discloses a high thermal conductivity silicon nitride substrate and a preparation method thereof, wherein the substrate is obtained by sequentially subjecting the silicon nitride green ceramic sheet after tape casting to a debinding process and a sintering process, and the debinding process is operated as follows: first, the debinding furnace is evacuated, and then the temperature is raised to 200°C, 350°C and 550°C in sequence, and protective gas is filled into the debinding furnace until the pressure in the furnace becomes 0.07-0.1Mpa, and then the filling of protective gas is stopped, and the temperature is kept warm for 0.5-2 hours: then the furnace is cooled to obtain a green ceramic sheet with a carbon atomic percentage of 0.090.11%. However, these prior arts do not solve the problem that the residual carbon content of the silicon nitride green sheet is different due to the difference in gravity and pressure, and the green sheet is prone to cracking.

[0005] Therefore, according to the above-mentioned related technologies, it is urgent to develop a new method for debonding and mounting silicon nitride substrates. Summary of the invention

[0006] In view of this, the purpose of the present invention is to propose a novel method for debonding and mounting silicon nitride substrates, so as to provide a method for debonding and mounting silicon nitride substrates with high productivity and low cracking potential.

[0007] Based on the above purpose, the present invention provides a novel method for debonding and mounting silicon nitride substrates.

[0008] A novel method for debonding and mounting silicon nitride substrates comprises the following steps:

[0009] Step S1. Silicon nitride powder is tape-casted to form a silicon nitride ceramic green sheet, boron nitride setter plates are placed on both sides in the vertical direction, the silicon nitride ceramic green sheet stack is vertically clamped between the two boron nitride setter plates, the boron nitride setter plates and the silicon nitride ceramic green sheet are fixed with bolts, and the green sheet is placed in a crucible;

[0010] Step S2: placing the crucible containing the silicon nitride ceramic green sheet into a muffle furnace for segmented debinding.

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

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

[0013] Preferably, the steps of tape casting in step S1 are as follows:

[0014] Silicon nitride powder, dispersant, sintering aid and ethanol are mixed and ball-milled once, and then plasticizer and adhesive are added thereto and ball-milled twice. The ball-milled slurry is filtered through a filter screen, and then a defoamer is added to perform vacuum centrifugal degassing for 30-45 minutes, and then formed by a scraper in a casting machine, dried, and wound, and finally vacuum-sealed and cold isostatically pressed to obtain a silicon nitride ceramic green sheet.

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

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

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

[0018] The conditions of the secondary ball milling are:

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

[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 glycerol;

[0023] The adhesive is polyethylene glycol.

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

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

[0026] Preferably, the step of segmented debinding in step S2 is as follows:

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

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

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

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

[0031] Step S205: After the temperature is lowered, the furnace door is opened.

[0032] Beneficial effects of the present invention:

[0033] The present invention provides a novel method for debonding and loading silicon nitride substrates. The present invention uses vertical debonding, that is, placing boron nitride support plates on both sides in the vertical direction, vertically clamping the silicon nitride ceramic green sheet stack between two boron nitride support plates, and fixing the boron nitride support plates and the silicon nitride ceramic green sheets with bolts. The weight of this debonding and loading method will not act between layers, the difference between green sheets is reduced, and the consistency of the green sheets after debonding is good. At the same time, in vertical debonding, the sheet spacing can be adjusted by bolts to be loose, the number of stacked sheets can be greatly increased, and the debonding capacity can be greatly increased. By regulating the temperature, pressure and time of segmented debonding, air debonding is used below 600°C, nitrogen debonding is used above 600°C, and heat preservation treatment is performed at 600°C, so that the green sheets can be close together, organic matter can be discharged as completely as possible, the amount of residual carbon is small, and it is not easy to deform and crack. The silicon nitride substrate obtained has high thermal conductivity and three-point bending strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 Schematic diagram of the arrangement of the silicon nitride ceramic green sheet and the boron nitride setter plate of Example 1 of the present invention;

[0036] Figure 2 Schematic diagram of the arrangement of the silicon nitride ceramic green sheet and the boron nitride support plate of Example 2 of the present invention. DETAILED DESCRIPTION

[0037] 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.

[0038] The sources and properties of some of the raw materials used in the present 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.; the defoamer model was defoamer Z-502, which was purchased from Shanghai Yuewan New Materials Co., Ltd.

[0040] Embodiment 1: A novel silicon nitride substrate arrangement and mounting method comprises the following steps:

[0041] S1. 55g silicon nitride powder, 2g ammonium polyacrylate, 3g sintering aid and 15g ethanol were mixed and ball milled once. 10mm and 5mm ZrO2 balls were selected as ball milling media with a mass ratio of 1:1, a rotation speed of 250rpm and a ball milling time of 2h. Then 5g glycerol and 8g polyethylene glycol were added thereto for a second ball milling. 10mm and 5mm ZrO2 balls were selected as ball milling media with a mass ratio of 1:1 and a rotation speed of 250rpm and a ball milling time of 2h. The speed is 250rpm, the ball milling time is 3h, the ball milled slurry is filtered through a filter, and then 0.5g of defoamer Z-502 is added for vacuum centrifugal degassing for 30min, and then the slurry is scraped in a casting machine, dried, and rolled, and then vacuum-sealed and cold isostatically pressed to obtain a silicon nitride ceramic green sheet, wherein the sintering aid is obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 1:2, the particle size of the sintering aid is 3μm, and the particle size of the silicon nitride powder is 0.3μm;

[0042] S2. Put boron nitride firing plates on both sides in the vertical direction, sandwich the silicon nitride ceramic green sheet stack vertically between the two boron nitride firing plates, use bolts to fix the boron nitride firing plates and the silicon nitride ceramic green sheet, and put it into a crucible, wherein the thickness of the silicon nitride ceramic green sheet is 0.1mm, and the thickness of the boron nitride firing plate is 3mm;

[0043] S3. The crucible containing the silicon nitride ceramic green sheet is placed in a muffle furnace for segmented debinding;

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

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

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

[0047] S7. In an atmosphere with a muffle furnace pressure of 0.3 MPa and a nitrogen flow rate of 100 L / min, the temperature was lowered to 120°C for 10 h;

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

[0049] Embodiment 2: A novel silicon nitride substrate arrangement and loading method comprises the following steps:

[0050] S1. 58g silicon nitride powder, 3g ammonium polyacrylate, 3.5g sintering aid and 18g ethanol were mixed and ball milled once. 10mm and 5mm ZrO2 balls were selected as ball milling media with a mass ratio of 1:1. The rotation speed was 260rpm and the ball milling time was 2.5h. Then 6g glycerol and 9g polyethylene glycol were added thereto for secondary ball milling. 10mm and 5mm ZrO2 balls were selected as ball milling media with a mass ratio of 1:1. The rotation speed is 260rpm, the ball milling time is 4h, the ball milled slurry is filtered through a filter, and then 0.6g of defoamer Z-502 is added for vacuum centrifugal degassing for 32min, and then the slurry is scraped in a casting machine, dried, and rolled, and then vacuum sealed and cold isostatically pressed to obtain a silicon nitride ceramic green sheet, wherein the sintering aid is obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 1:2, the particle size of the sintering aid is 3μm, and the particle size of the silicon nitride powder is 0.4μm;

[0051] S2. Put boron nitride setter plates on both sides in the vertical direction, sandwich the silicon nitride ceramic green sheet stack vertically between the two boron nitride setter plates, use bolts to fix the boron nitride setter plates and the silicon nitride ceramic green sheet, and put it into a crucible, wherein the thickness of the silicon nitride ceramic green sheet is 0.1 mm, and the thickness of the boron nitride setter plates is 3.5 mm;

[0052] S3. The crucible containing the silicon nitride ceramic green sheet is placed in a muffle furnace for segmented debinding;

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

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

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

[0056] S7. In an atmosphere with a muffle furnace pressure of 0.4 MPa and a nitrogen flow rate of 120 L / min, the temperature was lowered to 125°C for 11 h;

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

[0058] Embodiment 3: A novel silicon nitride substrate arrangement and mounting method comprises the following steps:

[0059] S1. 60g silicon nitride powder, 4g ammonium polyacrylate, 4g sintering aid and 18g ethanol were mixed and milled once. 10mm and 5mm ZrO2 balls were selected as the milling media in a mass ratio of 1:1. The rotation speed was 270rpm and the milling time was 3h. Then 6.5g glycerol and 10g polyethylene glycol were added thereto and milled twice. 10mm and 5mm ZrO2 balls were selected as the milling media in a mass ratio of 1:1. The rotation speed was 270rpm and the milling time was 3h. The speed is 270rpm, the ball milling time is 5h, the ball milled slurry is filtered through a filter, and then 0.8g of defoamer Z-502 is added for vacuum centrifugal degassing for 35min, and then it is scraped in a casting machine, dried, and rolled, and finally vacuum-sealed and cold isostatically pressed to obtain a silicon nitride ceramic green sheet, wherein the sintering aid is obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 2:3, the particle size of the sintering aid is 4μm, and the particle size of the silicon nitride powder is 0.5μm;

[0060] S2. Put boron nitride setter plates on both sides in the vertical direction, sandwich the silicon nitride ceramic green sheet stack vertically between the two boron nitride setter plates, use bolts to fix the boron nitride setter plates and the silicon nitride ceramic green sheet, and put it into a crucible, wherein the thickness of the silicon nitride ceramic green sheet is 0.2 mm, and the thickness of the boron nitride setter plates is 4 mm;

[0061] S3. The crucible containing the silicon nitride ceramic green sheet is placed in a muffle furnace for segmented debinding;

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

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

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

[0065] S7. In an atmosphere with a muffle furnace pressure of 0.5 MPa and a nitrogen flow rate of 180 L / min, the temperature was lowered to 130°C for 13 h;

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

[0067] Embodiment 4: A novel silicon nitride substrate arrangement and mounting method comprises the following steps:

[0068] S1. 62g silicon nitride powder, 5g ammonium polyacrylate, 4.5g sintering aid and 22g ethanol were mixed and ball milled once. 10mm and 5mm ZrO2 balls were selected as ball milling media with a mass ratio of 1:1. The rotation speed was 275rpm and the ball milling time was 3.5h. Then 7g glycerol and 11g polyethylene glycol were added thereto for secondary ball milling. 10mm and 5mm ZrO2 balls were selected as ball milling media with a mass ratio of 1:1. The rotation speed is 275rpm, the ball milling time is 6h, the ball milled slurry is filtered through a filter, and then 1g of defoamer Z-502 is added for vacuum centrifugal degassing for 40min, and then the slurry is scraped in a casting machine, dried, and rolled, and then vacuum sealed and cold isostatically pressed to obtain a silicon nitride ceramic green sheet, wherein the sintering aid is obtained by mixing yttrium oxide and magnesium oxide in a mass ratio of 2:4, the particle size of the sintering aid is 4.2μm, and the particle size of the silicon nitride powder is 0.6μm;

[0069] S2. Boron nitride support plates are placed on both sides in the vertical direction, and the silicon nitride ceramic green sheet is vertically sandwiched between two boron nitride support plates, and the boron nitride support plates and silicon nitride ceramic green sheets are fixed with bolts and placed in a crucible, wherein the thickness of the silicon nitride ceramic green sheet is 0.3 mm, and the thickness of the boron nitride support plate is 4 mm;

[0070] S3. The crucible containing the silicon nitride ceramic green sheet is placed in a muffle furnace for segmented debinding;

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

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

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

[0074] S7. In an atmosphere with a muffle furnace pressure of 0.6 MPa and a nitrogen flow rate of 220 L / min, the temperature was lowered to 140°C for 14 h;

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

[0076] Embodiment 5: A novel method for arranging and mounting silicon nitride substrates, comprising the following steps:

[0077] S1. Mix 65g silicon nitride powder, 6g ammonium polyacrylate, 5g sintering aid and 25g ethanol, and perform a ball milling. Select 10mm and 5mm ZrO2 balls as the ball milling medium, the mass ratio is 1:1, the speed is 280rpm, and the ball milling time is 4h. Then add 8g glycerol and 12g polyethylene glycol, and perform a secondary ball milling. Select 10mm and 5mm ZrO2 balls as the ball milling medium, the mass ratio is 1:1, the speed is The speed was 280 rpm, the ball milling time was 8 hours, the ball milled slurry was filtered through a filter, and then 1.2 g of defoamer Z-502 was added for vacuum centrifugal degassing for 45 minutes, and then the slurry was scraped in a casting machine, dried, and rolled, and then vacuum-sealed and cold isostatically pressed to obtain a silicon nitride ceramic green sheet, wherein 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. Put boron nitride setter plates on both sides in the vertical direction, sandwich the silicon nitride ceramic green sheet stack vertically between the two boron nitride setter plates, use bolts to fix the boron nitride setter plates and the silicon nitride ceramic green sheet, and put it into a crucible, wherein the thickness of the silicon nitride ceramic green sheet is 0.3mm, and the thickness of the boron nitride setter plates is 5mm;

[0079] S3. The crucible containing the silicon nitride ceramic green sheet is placed in a muffle furnace for segmented debinding;

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

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

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

[0083] S7. In an atmosphere with a muffle furnace pressure of 0.8 MPa and a nitrogen flow rate of 250 L / min, the temperature was lowered to 150°C for 15 h;

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

[0085] Comparative Example 1:

[0086] Compared with Example 1, this comparative example only replaces "placing boron nitride supporting plates on both sides in the vertical direction, vertically clamping the silicon nitride ceramic green sheet stack between the two boron nitride supporting plates, and fixing the boron nitride supporting plates and the silicon nitride ceramic green sheets with bolts" with "placing a boron nitride supporting plate at the bottom, placing the stacked silicon nitride ceramic green sheets on the boron nitride supporting plate, and placing a boron nitride supporting plate on the top of the green sheets". The remaining 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°C for 2h in an atmosphere with a muffle furnace pressure of 0.1MPa and an air flow rate of 200L / min" in the segmented debinding step. The remaining 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, the present comparative example only replaces the segmented debinding step with "in an atmosphere with a muffle furnace pressure of 0.1 MPa and an air flow rate of 200 L / min, heating from room temperature to 1100°C at a heating rate of 0.5°C / min, and cooling to 120°C in an atmosphere with a muffle furnace pressure of 0.3 MPa and a nitrogen flow rate of 100 L / min, and the cooling time is 10 h". The remaining steps and parameters are the same and will not be repeated in this comparative example, and a silicon nitride substrate is finally obtained.

[0091] Comparative Example 4:

[0092] Compared with Example 1, this comparative example only replaces the step of "cooling to 120°C for 10 hours in an atmosphere with a muffle furnace pressure of 0.3 MPa and a nitrogen flow rate of 100 L / min" in the segmented debinding step with "cooling to 300°C for 10 hours in an atmosphere with a muffle furnace pressure of 0.3 MPa and a nitrogen flow rate of 100 L / min". The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, a 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 green sheet is 0.1 mm" with "the thickness of the silicon nitride ceramic green sheet is 5 mm", and the remaining steps and parameters are the same and will not be repeated in this comparative example, and finally a silicon nitride substrate is obtained.

[0095] Performance Test:

[0096] Determination of fragmentation rate:

[0097] Silicon nitride ceramic green sheets are mass-produced according to the methods in Examples 1 to 5 and Comparative Examples 1 to 5, and the silicon nitride ceramic green sheets after debinding are sintered to obtain silicon nitride substrates, and their cracking rates are calculated;

[0098] Thermal conductivity determination:

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

[0100] Three-point bending strength test:

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

[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 adopts a vertical debinding and loading method, that is, boron nitride support plates are placed on both sides in the vertical direction, the silicon nitride ceramic green sheet stack is vertically clamped between the two boron nitride support plates, and the boron nitride support plates and the silicon nitride ceramic green sheets are fixed with bolts, while Comparative Example 1 adopts a traditional sandwich structure debinding and loading method, that is, a boron nitride support plate is placed at the bottom, the stacked silicon nitride ceramic green sheets are placed on the boron nitride support plate, and a boron nitride support plate is placed on the top of the green sheets. Example 1 and Comparative Example 1 are placed in crucibles of the same size for debinding. It can be found that the vertical debinding and loading method adopted in Example 1 can load more silicon nitride ceramic green sheets, such as Figure 1 and Figure 2As shown, this increases the amount of debinding furnace loading and increases production capacity. The traditional sandwich structure debinding and loading method is easily affected by gravity. The bottom green sheet is subjected to greater pressure, resulting in the colloid vapor being suppressed during the debinding process, making it difficult to completely discharge, resulting in an upper limit on the number of stacking layers. After reaching a certain number of layers, the green sheet cannot completely drain the colloid. At the same time, after the upper and lower sheets are debinded, the residual carbon content is different due to the pressure difference, and the remaining carbon content of the bottom green sheet is high. This causes the color of the sintered substrate to be inconsistent. Moreover, under the influence of gravity, the debinding rates of the upper and lower sheets are not synchronized, resulting in a time difference in the shrinkage of the green body, which makes the green sheet prone to defects such as warping and cracking; vertical debinding, the weight will not act between the layers, the difference between the green sheets is reduced, and the consistency of the green sheets after debinding is good. At the same time, in vertical debinding, the sheet spacing can be adjusted by bolts to increase the number of stacked sheets, so that the number of sheets in each stack will not be limited. The debinding capacity can be greatly improved.

[0108] By regulating the temperature, pressure and time of segmented debinding, air is used for debinding below 600°C, nitrogen is used for debinding above 600°C, and heat preservation treatment is performed at 600°C. The green sheets can be tightly packed together, organic matter can be discharged as completely as possible, the amount of residual carbon is small, and it is not easy to deform or crack. The obtained 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 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.

[0110] 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 novel method for disassembling and mounting silicon nitride substrates, characterized in that: The following steps are involved: Step S1. Silicon nitride powder is tape-casted to form a silicon nitride ceramic green sheet, boron nitride setter plates are placed on both sides in the vertical direction, the silicon nitride ceramic green sheet stack is vertically clamped between the two boron nitride setter plates, the boron nitride setter plates and the silicon nitride ceramic green sheet are fixed with bolts, and the green sheet is placed in a crucible; Step S2: placing the crucible containing the silicon nitride ceramic green sheet into a muffle furnace for segmented debinding.

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

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

4. The novel silicon nitride substrate debonding and mounting method according to claim 1, characterized in that: The steps of tape casting in step S1 are as follows: Silicon nitride powder, dispersant, sintering aid and ethanol are mixed and ball-milled once, and then plasticizer and adhesive are added thereto and ball-milled twice. The ball-milled slurry is filtered through a filter screen, and then a defoamer is added to perform vacuum centrifugal degassing for 30-45 minutes, and then formed by a scraper in a casting machine, dried, and wound, and finally vacuum-sealed and cold isostatically pressed to obtain a silicon nitride ceramic green sheet.

5. The novel silicon nitride substrate debonding and mounting method according to claim 4 is characterized in that: The mass ratio of the silicon nitride powder, dispersant, sintering aid, ethanol, plasticizer, adhesive and defoamer is 55-65:2-6:3-5:15-25:5-8:8-12:0.5-1.

2.

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

7. The novel silicon nitride substrate debonding and mounting method according to claim 4, 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 glycerol; The adhesive is polyethylene glycol.

8. The novel silicon nitride substrate debonding and mounting method according to claim 4, characterized in that: The particle size of the sintering aid is 3-5 μm.

9. The novel silicon nitride substrate debonding and mounting method according to claim 4, characterized in that: The particle size of the silicon nitride powder is 0.3-0.8 μm.

10. The novel silicon nitride substrate debonding and mounting method according to claim 1, characterized in that: The steps of segmented debinding in step S2 are as follows: Step S201. First, in an atmosphere with a muffle furnace pressure of 0.1-0.3 MPa and an air flow rate of 200-400 L / min, the temperature is raised from room temperature to 600°C at a heating rate of 0.5-0.8°C / min; Step S202. Maintain 600°C for 2-5h in an atmosphere with a muffle furnace pressure of 0.1-0.3MPa and an air flow rate of 200-400L / min; Step S203. In an atmosphere with a muffle furnace pressure of 0.1-0.3 MPa and a nitrogen flow rate of 100-300 L / min, the temperature is increased from 600°C to 1100°C at a heating rate of 0.5-0.8°C / min; Step S204. In an atmosphere with a muffle furnace pressure of 0.3-0.8 MPa and a nitrogen flow rate of 100-250 L / min, the temperature is lowered to 120-150° C. for 10-15 hours; Step S205: After the temperature is lowered, the furnace door is opened.

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