A gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity, a preparation method and applications thereof

Abstract

The application belongs to the technical field of heat dissipation and 3D packaging, and particularly relates to a gradient diamond / ceramic composite material for enhancing longitudinal thermal conductivity, a preparation method and application, the preparation method comprising the following steps: firstly, using a ceramic sheet as a substrate, processing through holes on the ceramic sheet to obtain a ceramic sheet with a through hole array; grinding the surface of the ceramic sheet with the through hole array obtained in S1 with diamond powder, and placing the ground substrate into a diamond micro powder ethanol solution for ultrasonic treatment; then, performing ultrasonic cleaning and drying; adding a grid support under the substrate, introducing mixed gas through a plasma chemical vapor deposition device, and adjusting the temperature to obtain a ceramic sheet with a diamond heat dissipation layer; finally, filling the through holes with metal through metal slurry vacuum filling to obtain a gradient diamond / ceramic composite material for enhancing longitudinal thermal conductivity.

Description

Technical Field

[0001] This invention belongs to the field of heat dissipation and 3D packaging technology, specifically relating to a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity, its preparation method, and its application. Background Technology

[0002] The rapid development of the semiconductor industry, in order to surpass Moore's Law, is driving integrated circuits towards 3D integration to increase the performance of corresponding semiconductor devices. Leading chip manufacturers have demonstrated their advancements in 3D packaging solutions, such as Intel's Foveros, TSMC's 3DFabric, and AMD's 3DV-Cache. 3D packaging leads to a higher number of chips per unit area, increased heat flux, and exacerbated hotspot issues and heat accumulation. This necessitates next-generation, more powerful heat dissipation methods to ensure the normal operation of chips after 3D packaging. Currently, the commonly used packaging substrate is the PCB board. While SiO2 is commonly used as the insulating material for through-holes in 3D IC packaging, and glass substrates have been proposed, their low thermal conductivity does not fundamentally solve the increasingly serious heat accumulation problem.

[0003] The patent disclosed in CN 112310051A, "Heat Dissipation Structure and Stacking Structure," demonstrates a three-dimensional chip packaging structure. It describes a heat dissipation layer with interconnecting structures on a substrate, connecting multiple layers of heat dissipation layers and multiple layers of chips. The substrate can be a silicon wafer, a compound semiconductor, or an alloy semiconductor. The heat dissipation layer material can be cobalt, titanium, tungsten, copper, aluminum, tantalum, titanium nitride, tantalum nitride, gold, silver, other metals, metal alloys, or combinations thereof. These heat dissipation materials are also conductive materials for electrical connections.

[0004] The patent disclosed in CN 210443552U, "Heat Dissipation Structure for System-in-Package", uses TIM (thermal interface material) to connect the chip and the heat dissipation device. The chip and the packaging substrate are electrically connected by wire bonding. The original packaging cover is replaced with a heat dissipation device to reduce the thermal resistance. The heat dissipation device is a heat dissipation fin, heat dissipation plate or heat pipe.

[0005] Some researchers have also used surface bonding to attach diamond films to substrate surfaces for heat dissipation. Patent CN118782474A discloses a "chip substrate and its preparation method," which involves bonding the bonding surfaces of a heat dissipation substrate and a chip substrate together. The heat dissipation substrate is made of polycrystalline diamond, has a diameter of 3 inches, and the chip substrate has a diameter of 12 inches; the chip substrate is a silicon wafer. However, for 3D packaging, this method only increases in-plane heat dissipation; the thermal conductivity in the longitudinal direction of the stacked 3D structure is not significantly improved. Summary of the Invention

[0006] To address the heat accumulation problem in existing technologies and the inability of materials to achieve efficient heat dissipation in the longitudinal direction, this invention provides a method for preparing a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity, comprising the following steps:

[0007] S1: Using a ceramic sheet as a substrate, through holes are processed on the ceramic sheet to obtain a ceramic sheet with an array of through holes;

[0008] S2: The ceramic sheet with through-hole array obtained in S1 is ground with diamond powder to polish the surface of the substrate. The polished substrate is then placed in a diamond micro powder ethanol solution for ultrasonic treatment. Then, ultrasonic cleaning and drying are performed.

[0009] S3: A grid support is added under the substrate, and a mixed gas is introduced through a plasma chemical vapor deposition device, and the temperature is adjusted to obtain a ceramic sheet with a diamond heat dissipation layer.

[0010] S4: Metal is vacuum-injected into through-holes through a metal slurry to obtain a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity.

[0011] Furthermore, the diameter of the through holes in the ceramic sheet described in S1 is 5μm-2mm, and the spacing between the through holes is 10μm-5mm.

[0012] Furthermore, the diamond particle size described in S2 is 1-20 μm.

[0013] Furthermore, the mixed gas mentioned in S3 is any one of the following: a mixture of methane and hydrogen, methane, a mixture of hydrogen and nitrogen, methane, a mixture of hydrogen and argon, or a mixture of methane, hydrogen, and carbon dioxide. The concentration of the mixed gas is 0.5% to 20%, and the gas pressure is 4-20 kPa. The temperature mentioned in S3 is 700-1000℃.

[0014] Furthermore, the metal mentioned in S4 is any one of copper, tungsten, or molybdenum.

[0015] Furthermore, the ceramic material described in S1 is any one of sintered silicon carbide, silicon nitride, or aluminum nitride.

[0016] A gradient diamond / ceramic composite material for enhancing longitudinal thermal conductivity, wherein the through-hole walls of the gradient diamond / ceramic composite material for enhancing longitudinal thermal conductivity have a gradient diamond heat dissipation layer.

[0017] Application of a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity, wherein the gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity is used in the preparation of ceramic substrate materials for semiconductor 3D packaging.

[0018] Beneficial effects

[0019] The present invention provides a method for preparing a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity. This method involves drilling special through holes on the surface of a ceramic sheet and growing a special gradient diamond coating on both the surface of the ceramic sheet and the walls of the through holes. This results in a diamond / ceramic composite substrate material that can conduct heat efficiently in both the longitudinal and planar directions, thus solving the problems of poor heat dissipation and thermal conductivity in the prior art.

[0020] This invention provides a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity. This diamond / ceramic composite substrate material allows for control of diamond grain size through pretreatment and growth conditions, resulting in diamond layers with varying grain sizes to meet the requirements of different via diameters. Simultaneously, directly growing diamond layers on the ceramic substrate effectively increases bonding strength with the substrate, reduces interfacial thermal resistance, ensures improved thermal conductivity, and enhances the planar and longitudinal thermal conductivity of the heat dissipation layer. Furthermore, the use of a mesh support to form a gradient diamond coating on the via walls facilitates matching the thermal expansion of metals during electrical connections, providing a new option for heat dissipation materials in electronic 3D packaging. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0022] Figure 1 This is a schematic diagram of the through holes, diamond layer, and filling material on the ceramic sheet according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the mesh support during growth according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram illustrating the enhancement of longitudinal heat dissipation through the growth of a gradient coating on the through-hole wall of a ceramic sheet according to an embodiment of the present invention.

[0025] Figure 4 The images shown are scanning electron microscope (SEM) images and corresponding Raman spectra of the gradient coating grown on the pore walls according to an embodiment of the present invention.

[0026] Figure Labels

[0027] 1. Ceramic substrate; 2. Diamond grown on the surface; 3. Through-hole; 4. Diamond grown inside the hole wall; 5. Through-hole filling material; 6. Mesh support. Detailed Implementation

[0028] The following will describe in conjunction with embodiments 1 to 5 of the present invention and the appendix. Figures 1-4 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] S1: Uses 2mm thick sintered silicon carbide ceramic sheets without through holes;

[0031] S2: The sintered silicon carbide ceramic sheet without through holes in S1 is ground with W10 diamond powder to polish the surface of the sintered silicon carbide. Then, the substrate is ultrasonically treated with W10 diamond powder ethanol suspension for 30 minutes. After cleaning and drying, the ceramic sheet is obtained.

[0032] S3: Place the ceramic sheet in a plasma chemical vapor deposition apparatus, add a grid support under the ceramic sheet, and then introduce a mixed gas of methane and hydrogen. With a gas pressure of 13.0 kPa, a substrate temperature of 910 °C, and a methane concentration of 8%, the growth time is 6 h, and a diamond layer with an average grain size of about 12 μm is obtained.

[0033] S4: Tungsten metal is vacuum-injected into through-holes to obtain a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity.

[0034] The composite material obtained in Example 1, after being heated for 120 seconds at 100°C on a heating table, resulted in a temperature of 89.82°C for the un-drilled diamond / ceramic composite substrate. This is approximately 7.6% higher than the 83.49°C of a pure SiC ceramic sheet of the same thickness, indicating better thermal conductivity.

[0035] Combination Figures 1-4 , Figure 1 and Figure 2 It can be seen that the grid support used in the embodiment is Figure 4 This describes the actual morphology and composition observed on the pore walls. Figure 3 It is Figure 4 A visualized view was created; therefore, the resulting gradient coating is as follows: Figure 3 Demonstration: A diamond coating is formed on the upper surface of the substrate and at the orifice. Moving downwards from the orifice, the central region contains a mixed phase of diamond and graphite, while further down, near the bottom, it consists of a mixed phase of graphite and graphene. The diamond content decreases from top to bottom, while the graphite and graphene content increases. This gradient coating structure is used to regulate thermal expansion. (Diamond alone has a low coefficient of thermal expansion, significantly different from that of metals.)

[0036] Example 2

[0037] S1: Drill through holes in a 2mm thick ceramic sheet. The diameter of the through holes is 700μm and the spacing between the through holes is 4mm, to obtain a sintered silicon carbide ceramic sheet with an array of through holes.

[0038] S2: The sintered silicon carbide ceramic sheet with through-hole array obtained in S1 is ground with W10 diamond powder. Then, the substrate is ultrasonically treated with W10 diamond powder ethanol suspension for 30 minutes. After cleaning and drying, the ceramic sheet is obtained.

[0039] S3: The ceramic sheet obtained in S2 was placed in a plasma chemical vapor deposition apparatus. A grid support was added under the ceramic sheet, and a mixture of methane and hydrogen gas was introduced. The growth was carried out for 6 hours at a gas pressure of 11.00 kPa, a substrate temperature of 930 °C, and a methane concentration of 8%, resulting in a diamond layer with an average grain size of 8 μm.

[0040] S4: Metallic copper is vacuum-injected into through-holes through a metal slurry to obtain a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity.

[0041] The composite material obtained in Example 2, after heating at 100°C for 120 seconds, resulted in a diamond / ceramic composite substrate temperature of 88.74°C after drilling. This is approximately 6.3% higher than the 83.49°C of a pure SiC ceramic sheet of the same thickness, indicating better thermal conductivity. However, due to the influence of the gas phase in the through-hole, the thermal conductivity is slightly lower than that of the un-drilled diamond / ceramic composite substrate in Example 1.

[0042] The sample in Example 2, after sealing the through-hole with copper metal, had its thermal conductivity tested using the laser scintillation method. The thermal conductivity was close to 500 W / (mK), which significantly exceeded the thermal conductivity of commonly used ceramic substrates (the theoretical thermal conductivity of aluminum nitride ceramics, which is considered to have high thermal conductivity, is 320 W / (mK), the thermal conductivity of commercial silicon nitride ceramic Toshiba TSN-90 is 90 W / (mK), and the thermal conductivity of laboratory samples is reported to be 170 W / (mK)).

[0043] Example 3

[0044] S1: Drill through holes in a 2mm thick ceramic sheet. The diameter of the through holes is 600μm and the spacing between the through holes is 4mm, to obtain a sintered silicon carbide ceramic sheet with an array of through holes.

[0045] S2: The sintered silicon carbide ceramic sheet with through-hole array obtained in S1 is ground with W10 diamond powder. Then, the substrate is ultrasonically treated with W10 diamond powder ethanol suspension for 30 minutes. After cleaning and drying, the ceramic sheet is obtained.

[0046] S3: The ceramic sheet obtained in S2 was placed in a plasma chemical vapor deposition apparatus. A grid support was added under the ceramic sheet, and a mixture of methane and hydrogen gas was introduced. The growth was carried out for 6 hours at a gas pressure of 12.00 kPa, a substrate temperature of 860 °C, and a methane concentration of 6%, resulting in a diamond layer with an average grain size of 11 μm.

[0047] S4: Metallic copper is vacuum-injected into through-holes through a metal slurry to obtain a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity.

[0048] The composite material obtained in Example 3, after heating at 100°C for 120 seconds, resulted in a diamond / ceramic composite substrate temperature of 87.88°C after reducing the aperture diameter. This temperature is approximately 5.3% higher than that of a pure SiC ceramic substrate of the same thickness (83.49°C), indicating improved thermal conductivity.

[0049] Example 4

[0050] S1: Drill through holes in a 2mm thick ceramic sheet. The diameter of the through holes is 600μm and the spacing between the through holes is 4mm, to obtain a sintered silicon nitride ceramic sheet with an array of through holes.

[0051] S2: The sintered silicon carbide ceramic sheet with through-hole array obtained in S1 is ground with W10 diamond powder. Then, the substrate is ultrasonically treated with W10 diamond powder ethanol suspension for 30 minutes. After cleaning and drying, the ceramic sheet is obtained.

[0052] S3: The ceramic sheet obtained in S2 was placed in a plasma chemical vapor deposition apparatus. A grid support was added under the ceramic sheet, and a mixture of methane and hydrogen gas was introduced. The growth was carried out for 6 hours at a gas pressure of 11.00 kPa, a substrate temperature of 920 °C, and a methane concentration of 8%, resulting in a diamond layer with an average grain size of 10 μm.

[0053] S4: Metallic copper is vacuum-injected into through-holes through a metal slurry to obtain a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity.

[0054] The composite material obtained in Example 4, after being heated for 120 seconds at 100°C on a heating table, resulted in a diamond / ceramic composite substrate temperature of 87.12°C after the ceramic substrate was replaced. This temperature was approximately 3.8% higher than the 83.92°C of a pure silicon nitride ceramic substrate of the same thickness, indicating improved thermal conductivity.

[0055] Example 5

[0056] S1: Drill through holes in a 0.5mm thick ceramic sheet. The diameter of the through holes is 600μm and the spacing between the through holes is 4mm, to obtain a sintered silicon carbide ceramic sheet with an array of through holes.

[0057] S2: The sintered silicon carbide ceramic sheet with through-hole array obtained in S1 is ground with W10 diamond powder. Then, the substrate is ultrasonically treated with W10 diamond powder ethanol suspension for 60 min. After cleaning and drying, the ceramic sheet is obtained.

[0058] S3: The ceramic sheet obtained in S2 was placed in a plasma chemical vapor deposition apparatus. A grid support was added under the ceramic sheet, and a mixture of methane and hydrogen gas was introduced. The growth was carried out for 6 hours at a gas pressure of 11.00 kPa, a substrate temperature of 930 °C, and a methane concentration of 8%, resulting in a diamond layer with an average grain size of 13 μm.

[0059] S4: Metallic copper is vacuum-injected into through-holes through a metal slurry to obtain a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity.

[0060] The composite material obtained in Example 5, after heating at 100°C for 120 seconds on a heating table, resulted in a diamond / ceramic composite substrate temperature of 93.00°C after reducing the thickness of the ceramic substrate. This temperature is approximately 11.2% higher than the 83.60°C of a pure SiC ceramic substrate of the same thickness. Due to the reduced thickness of the ceramic sheet, the effect of the diamond layer is enhanced, and the thermal conductivity is significantly improved.

[0061] Table 1 shows a comparison of the temperatures after heating in Examples 1-5. Figure 4 We can obtain the scanning electron microscope (SEM) image of the gradient coating growing on the pore walls and the corresponding Raman spectrum. Figure 4 From this, we can see that the orifice is made of diamond, the middle part is a diamond / graphite mixed phase, and the bottom of the orifice is a graphite / graphene mixed phase.

[0062] Table 1. Comparison of temperatures after heating in Examples 1-5

[0063]

[0064] Table 2 shows that, due to the relatively large coefficient of thermal expansion of graphite in the vertical direction, the gradient layer formed by graphite mixed with diamond or graphene can adjust the coefficient of thermal expansion, reducing the large difference in the coefficients of thermal expansion between diamond and copper, and thus better matching the thermal expansion of the metal. Table 2 is as follows:

[0065] Table 2. Relevant thermal properties of Cu, diamond, graphite, and graphene.

[0066]

[0067]

[0068] The present invention provides a method for preparing gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity. This method significantly increases longitudinal thermal conductivity by using a grid support and through-holes, thus solving the heat accumulation problem in 3D packaging in the prior art. The grid support facilitates gas flow and allows gradient diamond coating to grow on the walls of the through-holes, which is beneficial for matching the thermal expansion during electrical connections.

Claims

1. A method for preparing a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity, characterized in that, Includes the following steps: S1: Using a ceramic sheet as a substrate, through holes are processed on the ceramic sheet to obtain a ceramic sheet with an array of through holes; S2: The ceramic sheet with through-hole array obtained in S1 is ground with diamond powder to polish the surface of the substrate, and the polished substrate is placed in a diamond micro powder ethanol solution for ultrasonic treatment. Then, ultrasonic cleaning and drying are performed. S3: A grid support is added under the substrate, and a mixed gas is introduced through a plasma chemical vapor deposition device while adjusting the temperature to obtain a ceramic sheet with a diamond heat dissipation layer; the diamond heat dissipation layer forms a diamond coating on the upper surface of the substrate and in the orifice area, a mixed phase coating of diamond and graphite in the middle area of ​​the orifice, and a mixed phase coating of graphite and graphene in the bottom area of ​​the orifice; the mixed gas is any one of methane and hydrogen mixture, methane, hydrogen and nitrogen mixture, methane, hydrogen and argon mixture, methane, hydrogen and carbon dioxide mixture, the concentration of the mixed gas is 0.5% to 20%, the gas pressure is 4-20 kPa; the temperature is 700-1000℃; S4: Metal is vacuum-injected into through-holes through a metal slurry to obtain a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity.

2. The method for preparing a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity according to claim 1, characterized in that, The diameter of the through holes in the ceramic sheet described in S1 is 5μm-2mm, and the spacing between the through holes is 10μm-5mm.

3. The method for preparing a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity according to claim 1, characterized in that, The diamond particle size described in S2 is 1-20 μm.

4. The method for preparing a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity according to claim 1, characterized in that, The metal mentioned in S4 is any one of copper, tungsten, or molybdenum.

5. The method for preparing a gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity according to claim 1, characterized in that, The ceramic sheet material mentioned in S1 is any one of sintered silicon carbide, silicon nitride, or aluminum nitride.

6. A gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity obtained by the preparation method according to any one of claims 1 to 5, characterized in that, The aforementioned gradient diamond / ceramic composite material for enhancing longitudinal thermal conductivity has a gradient diamond heat dissipation layer on the pore walls.

7. The application of the gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity according to claim 6, characterized in that, The aforementioned gradient diamond / ceramic composite material with enhanced longitudinal thermal conductivity is used in the preparation of ceramic substrate materials for semiconductor 3D packaging.

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