Diamond-reinforced silicon nitride composite material with metallurgical-grade interface bonding and preparation method of diamond-reinforced silicon nitride composite material

Abstract

The invention discloses a diamond reinforced silicon nitride composite material with metallurgical-grade interface bonding and a preparation method thereof, the diamond reinforced silicon nitride composite material comprises a silicon nitride substrate and a diamond reinforced phase dispersed in the silicon nitride substrate, and metallurgical-grade interface bonding is realized between the diamond reinforced phase and the silicon nitride substrate through an in-situ generated silicon nitride layer. The invention relates to the technical field of ceramic material preparation. According to the diamond-reinforced silicon nitride composite material with metallurgical-grade interface bonding and the preparation method thereof, diamond powder coated with silicon oxide is used as a reinforcing phase, and is sintered in an environment of 1500-1800 DEG C after being compounded with silicon nitride powder, so that a diamond-reinforced silicon nitride composite material sintered body with metallurgical-grade interface bonding can be obtained; the high thermal conductivity characteristic of the material has a wide application prospect in the field of electronic packaging.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic material preparation, in particular to a diamond reinforced silicon nitride composite material with metallurgical grade interface bonding and a preparation method thereof. BACKGROUND

[0002] With the vigorous development of microelectronic devices, new requirements have been put forward for the thermal performance of electronic packaging materials. Silicon nitride ceramics are pushed to the new market due to their excellent thermal conductivity. However, due to the existence of Si-N covalent bond in silicon nitride, the interatomic binding force is strong, which makes it difficult to densify and sinter, resulting in low actual thermal conductivity, which is difficult to meet the increasing heat dissipation demand of the electronic industry. At present, long time, ultra-high temperature gas pressure sintering is usually used to prepare silicon nitride ceramics with high thermal conductivity. However, the silicon nitride ceramics prepared by long time, ultra-high temperature sintering have the defects of high energy consumption, long cycle, high cost, and poor mechanical properties of the ceramic. Therefore, how to quickly prepare silicon nitride ceramics with high thermal conductivity is a difficult problem to be solved. Diamond is the natural material with the highest thermal conductivity known so far. Preparing diamond reinforced silicon nitride composite material with diamond as the reinforcing phase is an effective method to improve the thermal conductivity of silicon nitride ceramics. However, due to the surface inertness of diamond and silicon nitride, the interface bonding of diamond reinforced silicon nitride composite material is poor, which seriously affects the thermal and mechanical properties of the composite material.

[0003] At present, a transition metal plating layer is usually plated on the surface of diamond to form a transition metal carbide transition layer between diamond and silicon nitride to solve the interface bonding problem between diamond and silicon nitride. However, most transition metal carbides have poor insulating properties, which greatly limits the application of diamond reinforced silicon nitride composite material in the field of electronic packaging.

[0004] In order to solve the above problems, the present application innovatively plates a silicon oxide plating layer on the surface of diamond. In the subsequent composite material sintering process, silicon nitride is generated in situ on the surface of diamond by high-temperature carbon thermal reduction reaction, realizing metallurgical grade interface bonding between diamond and silicon nitride. This method solves the problem of poor interface bonding between diamond and silicon nitride, and does not introduce other impurities, which does not adversely affect the insulating property and dielectric property of the composite material.

[0005] After searching, the publication with application number CN202510881050.3 provides a hot-pressing sintering preparation method of diamond reinforced silicon nitride composite material. The method uses titanium plated diamond as the reinforcing phase, and the Ti-O-Ce / Mg solid solution formed by the titanium plating layer and the sintering reaction in the hot-pressing sintering process reduces the interface energy barrier, but this method cannot solve the problems of reduced insulation strength and increased dielectric loss caused by Ti plating layer.

[0006] The present application is essentially different from the above-mentioned published application. Specifically, the focus of the application is on the hot-pressing sintering process and formula of diamond-reinforced silicon nitride composite material. The present application does not limit the preparation method of the composite material. The focus of the present application is on the carbothermic reduction reaction between the silicon oxide plated on the surface of the diamond and the diamond during the sintering process, so that an interface with a metallurgical grade bonding strength is formed in situ on the surface of the diamond, thereby reducing the interface thermal resistance of the diamond-reinforced silicon nitride composite material. The silicon nitride layer formed in situ on the surface of the diamond not only solves the problem of poor interface bonding between the diamond and the silicon nitride, but also does not introduce other impurities, especially does not introduce a metal carbide transition layer, thereby improving the insulation and dielectric properties of the composite material. SUMMARY

[0007] To achieve the above-mentioned purpose, the present application is implemented by the following technical solutions: a diamond-reinforced silicon nitride composite material with a metallurgical grade interface bonding and a preparation method thereof, comprising the following steps: S1, silicon oxide plating: plating a silicon oxide plating layer on the surface of the diamond particles, and the plating method includes but is not limited to magnetron sputtering, atomic layer deposition, chemical vapor deposition, etc.; S2, carbothermic reduction reaction: forming silicon nitride in situ on the surface of the diamond through a carbothermic reduction reaction of the diamond particles plated with the silicon oxide plating layer; S3, composite material preparation: combining the heat-treated diamond as a reinforcing phase with silicon nitride powder to prepare a diamond-reinforced silicon nitride composite material through sintering.

[0008] Preferably, the thickness of the silicon oxide plating layer is not greater than 2µm, and the ratio of the thickness of the silicon oxide plating layer to the particle size of the diamond is less than 0.5.

[0009] Preferably, the carbothermic reduction process in step S2 is carried out in a nitrogen-containing atmosphere, which includes one or both of nitrogen gas and ammonia gas, and combinations thereof with hydrogen gas and inert gas.

[0010] Preferably, the oxygen content in the nitrogen-containing atmosphere is less than 10%, and the pressure of the nitrogen-containing atmosphere is 50-150kPa.

[0011] Preferably, the carbothermic reduction temperature is 1300-1600°C, and the reaction time is 1-7h.

[0012] The interface of the diamond-reinforced silicon nitride composite material prepared by the above-mentioned method is a direct metallurgical grade bonding between the diamond and the silicon nitride.

[0013] The relative density of the diamond-reinforced silicon nitride composite material prepared by the above-mentioned method is greater than 99%, and the thermal conductivity is greater than 200W / mk.

[0014] The present application provides a diamond reinforced silicon nitride composite material with metallurgical grade interface bonding and a preparation method thereof. The present application has the following advantages: (1) The diamond reinforced silicon nitride composite material with metallurgical grade interface bonding and the preparation method thereof are prepared by coating silicon oxide on the surface of diamond powder, and then sintering the composite of the diamond powder and silicon nitride powder at 1500-1700°C. The sintered body of the diamond reinforced silicon nitride composite material with metallurgical grade interface bonding has a wide application prospect in the field of electronic packaging due to its high thermal conductivity.

[0015] (2) The diamond reinforced silicon nitride composite material with metallurgical grade interface bonding and the preparation method thereof are prepared by coating silicon oxide on the surface of diamond powder, and then sintering the composite of the diamond powder and silicon nitride powder at 1500-1700°C. The sintered body of the diamond reinforced silicon nitride composite material with metallurgical grade interface bonding has a wide application prospect in the field of electronic packaging due to its high thermal conductivity. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present application.

[0017] The preparation of the silicon oxide coating on the surface of diamond can be performed by various conventional methods in the industry, including magnetron sputtering, high-temperature atomic layer deposition, chemical vapor deposition, etc. In addition, the silicon oxide layer can also be formed by adding silicon oxide powder and hot oxidized silicon nitride powder to the diamond / silicon nitride composite material formula, and then allowing the silicon oxide to react with the diamond reinforcing phase to form a silicon nitride interface layer during the preparation of the composite material.

[0018] In the present application, the carbon thermal reduction time is 1-7h. It should be noted that the carbon thermal reduction process of the present application can be performed separately or during the sintering process of the composite material. That is, the silicon oxide coated diamond and the silicon nitride can be directly combined and sintered in a nitrogen-containing atmosphere to allow the carbon thermal reduction reaction between the diamond and the silicon oxide to form a silicon nitride coating layer, which is also within the protection scope of the present application.

[0019] In the present application, the pyrolysis process is carried out in a nitrogen-containing atmosphere, and the nitrogen-containing reducing atmosphere refers to a nitrogen atmosphere, an ammonia atmosphere, or a mixed atmosphere of nitrogen, ammonia, hydrogen, and inert gas. The atmosphere is preferably completely free of oxygen. The nitrogen-containing atmosphere has a pressure of 50-150 kPa.

[0020] Secondly, the preparation method of the diamond / silicon nitride composite material of the present application is described: the diamond particles coated with silicon nitride having a metallurgical level interface bonding obtained by the above preparation method are used as the reinforcing phase, and the diamond / silicon nitride composite material is obtained by compounding with sintering aids and silicon nitride powder and molding, and then sintering in an environment of 1500-1700°C to obtain a dense diamond / silicon nitride composite material, the relative density of the composite material is more than 99%, and the thermal conductivity is greater than 200 W / mk.

[0021] It is explained that, since diamond and silicon nitride have strong surface inertness, it is difficult to obtain a metallurgical level interface bonding between the two by traditional sintering methods, and traditional methods all improve the bonding strength between the two phases by preparing a metal carbide transition layer between diamond and silicon nitride. However, the present application constructs a metallurgical level bonding diamond / silicon nitride interface through carbothermal reduction reaction between diamond and silicon oxide.

[0022] In the present application, the molding method of the composite material is not limited, and known powder molding technologies such as press molding, injection molding, and isostatic pressing molding can be used.

[0023] In the present application, the sintering method of the composite material is not limited, as long as the sintered body can be densified, and normal pressure sintering or gas pressure sintering in a nitrogen-containing atmosphere can be used, in addition, known technologies for simultaneous molding and sintering such as hot isostatic pressing sintering, discharge plasma sintering, and hot pressing sintering can also be used.

[0024] The present application is further described below in combination with examples.

[0025] Example 1, the present application provides a technical solution: A 500 nm thick silicon oxide film is coated on a 150 µm diamond surface by magnetron sputtering, and the coated diamond is heat treated at 1400°C for 2h in a nitrogen atmosphere (pressure 101 kPa) to obtain silicon nitride-coated diamond particles. The silicon nitride-coated diamond particles, silicon nitride powder, and sintering aids (yttrium oxide and magnesium oxide, mass ratio 7:3) are mixed in a volume ratio of 50:49:1, and then dry-pressed to form a shape, and then hot-pressed and sintered in a nitrogen atmosphere for 2h, the sintering temperature is 1600°C, and the sintering time is 2h. A diamond-reinforced silicon nitride composite material is obtained.

[0026] Example 2, the present application provides a technical solution: The 150 µm diamond surface is coated with a 100 nm thick silicon oxide film using high-temperature atomic layer deposition technology. The coated diamond is heat-treated at 1300°C for 2 hours in a nitrogen atmosphere (pressure 101 kPa) to obtain silicon nitride-coated diamond particles. The silicon nitride-coated diamond particles, silicon nitride powder, and sintering aids (lithium oxide and magnesium oxide, mass ratio 7:3) are mixed in a volume ratio of 50:49:1, then dry-pressed to form a green body, and then sintered at 1620°C for 2 hours in a nitrogen atmosphere to obtain a diamond-reinforced silicon nitride composite material.

[0027] In Example Three, the present application provides a technical solution: The 200 µm diamond surface is coated with a 100 nm thick silicon oxide film using high-temperature chemical vapor deposition technology. The coated diamond is heat-treated at 1350°C for 2 hours in a nitrogen atmosphere (pressure 101 kPa) to obtain silicon nitride-coated diamond particles. The silicon nitride-coated diamond particles, silicon nitride powder, and sintering aids (lanthanum oxide and magnesium oxide, mass ratio 7:3) are mixed in a volume ratio of 45:54:1, then dry-pressed to form a green body, and then sintered at 1700°C for 2 hours in a nitrogen atmosphere to obtain a diamond-reinforced silicon nitride composite material.

[0028] In Example Four, the present application provides a technical solution: The 400 µm diamond surface is coated with a 500 nm thick silicon oxide film using high-temperature chemical vapor deposition technology. The coated diamond is heat-treated at 1450°C for 2 hours in a nitrogen atmosphere (pressure 101 kPa) to obtain silicon nitride-coated diamond particles. The silicon nitride-coated diamond particles, silicon nitride powder, and sintering aids (lutetium oxide and magnesium oxide, mass ratio 7:3) are mixed in a volume ratio of 45:54:1, then dry-pressed to form a green body, and then sintered at 1800°C for 2 hours in a nitrogen atmosphere to obtain a diamond-reinforced silicon nitride composite material.

[0029] In Example Five, the present application provides a technical solution: The 150 µm diamond surface is coated with a 200 nm thick silicon oxide film using magnetron sputtering technology. The coated diamond, silicon nitride powder, and sintering aids (calcium oxide and magnesium oxide, mass ratio 7:3) are mixed in a volume ratio of 50:49:1, then tape-cast to form a green body, and then sintered at 1700°C for 3 hours in a nitrogen atmosphere to obtain a diamond-reinforced silicon nitride composite material.

[0030] In Comparative Example One, the present application provides a technical solution: The uncoated 150 pm diamond, silicon nitride powder, sintering aids (yttria and magnesium oxide, mass ratio 7:3) are mixed in a ratio of 50:49:1 by volume, then flow casting, and then hot-press sintering under a nitrogen atmosphere, with a sintering temperature of 1700 °C and a sintering time of 3 h, to obtain a diamond-reinforced silicon nitride composite material.

[0031] In Comparative Example Two, the present application provides a technical solution: The silicon nitride powder is heat-oxidized in an air atmosphere at 1100 °C for 1 h, and then the uncoated 150 pm diamond, silicon nitride powder, sintering aids (yttria and magnesium oxide, mass ratio 7:3) are mixed in a ratio of 50:49:1 by volume, then flow casting, and then hot-press sintering under a nitrogen atmosphere, with a sintering temperature of 1700 °C and a sintering time of 3 h, to obtain a diamond-reinforced silicon nitride composite material.

[0032] In Comparative Example Three, the present application provides a technical solution: The 150 pm diamond is coated with a 200 nm thick silicon oxide coating layer using a magnetron sputtering technique, and then the coated diamond is heat-treated at 1600 °C for 1 h in a nitrogen atmosphere (pressure 101 kPa) to obtain silicon nitride-coated diamond particles. Then the coated diamond, silicon nitride powder, and sintering aids (yttria and magnesium oxide, mass ratio 7:3) are mixed in a ratio of 50:49:1 by volume, then flow casting, and then hot-press sintering under a nitrogen atmosphere, with a sintering temperature of 1700 °C and a sintering time of 3 h, to obtain a diamond-reinforced silicon nitride composite material.

[0033] In Comparative Example Four, the present application provides a technical solution: The 150 pm diamond is coated with a 200 nm thick silicon oxide coating layer using a magnetron sputtering technique, and then the coated diamond is heat-treated at 1350 °C for 10 h in a nitrogen atmosphere (pressure 101 kPa) to obtain silicon nitride-coated diamond particles. Then the coated diamond, silicon nitride powder, and sintering aids (yttria and magnesium oxide, mass ratio 7:3) are mixed in a ratio of 50:49:1 by volume, then flow casting, and then hot-press sintering under a nitrogen atmosphere, with a sintering temperature of 1700 °C and a sintering time of 3 h, to obtain a diamond-reinforced silicon nitride composite material.

[0034] Performance test; The interfacial bonding strength between the diamond and the silicon nitride can be controlled by the thickness of the silicon oxide coating layer on the diamond surface and the heat treatment temperature and time. In addition, the diamond-reinforced silicon nitride composite materials of Examples 1-5 and Comparative Examples 1-4 shown in Table 1 are prepared using the same method as Example 1, wherein the interfacial layer preparation method and the composite material densification scheme are shown in Table 1.

[0035] Table 1 shows the specific preparation conditions and final composite material properties information of diamond reinforced silicon nitride composites in Examples 1-5 and Comparative Examples 1-4.

[0036] The above table is an interface layer preparation method and composite material preparation method and composite material performance characteristics test table.

[0037] It is to be noted that the relational terms herein, such as first and second, and the like, are used solely to distinguish one from another entity or action without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0038] While embodiments of the present application have been shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the application. The scope of the application is defined by the appended claims and their equivalents.

Claims

1. A diamond reinforced silicon nitride composite material having a metallurgical grade interfacial bond, characterized by: The silicon nitride composite material comprises a silicon nitride matrix and a diamond reinforcing phase dispersed in the silicon nitride matrix, and a metallurgical interface between the diamond reinforcing phase and the silicon nitride matrix is formed by an in-situ generated silicon nitride layer. The in-situ generated silicon nitride layer is formed by a silicon oxide plating layer plated on the surface of the diamond reinforcing phase and the diamond in a nitrogen-containing atmosphere through a carbothermic reduction reaction.

2. A method of making a diamond reinforced silicon nitride composite material having a metallurgical grade interfacial bond, characterized in that, The method comprises the following steps: Step 1: Silicon oxide plating: a silicon oxide plating layer is plated on the surface of the diamond particles, and the plating method includes but is not limited to magnetron sputtering, atomic layer deposition and chemical vapor deposition; Step 2: Carbothermic reduction reaction: the diamond particles plated with the silicon oxide plating layer in step 1 are placed in a nitrogen-containing atmosphere, and heat treatment is performed at 1300-1600 ℃ and 50-150 kPa to make the silicon oxide and the diamond undergo a carbothermic reduction reaction, so that a silicon nitride layer is in-situ generated on the surface of the diamond particles, and diamond particles coated with silicon nitride are obtained; Step 3: Composite material preparation: the diamond particles coated with silicon nitride in step S2 are used as reinforcing phases, mixed with silicon nitride powder and sintering aids, uniformly formed, and then sintered in a nitrogen-containing atmosphere to obtain the diamond-reinforced silicon nitride composite material.

3. The method for preparing a diamond-reinforced silicon nitride composite material with metallurgical-grade interfacial bonding according to claim 2, characterized in that: The thickness of the silicon oxide plating layer in step 1 is not more than 2 μm, and the ratio of the thickness of the silicon oxide plating layer to the particle size of the diamond particles is less than 0.

5.

4. The method of claim 3, wherein the diamond reinforced silicon nitride composite material having a metallurgical grade interface bond is prepared by the steps of: providing a silicon nitride substrate; providing a diamond layer; and bonding the diamond layer to the silicon nitride substrate. The nitrogen-containing atmosphere in steps 2 and 3 is one or both of nitrogen and ammonia, or a mixed atmosphere of nitrogen, ammonia, hydrogen and inert gas. The oxygen content in the nitrogen-containing atmosphere is less than 10%.

5. The method of claim 2, wherein the diamond reinforced silicon nitride composite material having metallurgical grade interface bonding is characterized by: The carbothermic reduction time in step 2 is 1-7 h.

6. The method for preparing a diamond-reinforced silicon nitride composite material with metallurgical-grade interfacial bonding according to claim 2, characterized in that: The sintering temperature in step 3 is 1500-1800 ℃, and the sintering time is 2-3 h. The sintering method is normal pressure sintering, reaction sintering, gas pressure sintering, hot pressing sintering, hot isostatic pressing sintering or spark plasma sintering.

7. The method for preparing a diamond-reinforced silicon nitride composite material with metallurgical-grade interfacial bonding according to claim 2, characterized in that: The sintering aid in step 3 is one of a mixture of rare earth oxides and magnesium oxide, or a mixture of part of alkali metal oxides, alkaline earth metal oxides and magnesium oxide. When the sintering aid is the mixture of rare earth oxides and magnesium oxide, the mass ratio of the two is 7:3; when the sintering aid is the mixture of alkali metal oxides or alkaline earth metal oxides and magnesium oxide, the mass ratio of the two is 7:

3.

8. The method of claim 2, wherein the diamond reinforced silicon nitride composite material having metallurgical grade interfacial bonding is characterized by: The volume ratio of the diamond particles coated with silicon nitride, the silicon nitride powder and the sintering aid in step S3 is 30-60:49-54:1-8.

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