Low-thermal-resistance thermal interface structure formed by oppositely staggered growth of carbon nanotubes and method

Abstract

The invention discloses a low-thermal-resistance thermal interface structure formed by oppositely and alternately growing carbon nanotubes and a method, the carbon nanotubes are oppositely and alternately grown in a microchannel formed by silicon oxide-silicon oxide bonding, so that a winding structure between the nanotubes is realized, the contact area is effectively increased, the contact distance is reduced, and the thermal resistance of the carbon nanotubes is improved. And the interface thermal resistance is obviously reduced to below 1mm < 2 > K / W and is lower than the contact thermal resistance 4mm < 2 > K / W which can be realized by a pressing method. According to the technical scheme, the distribution and growth conditions of the catalyst are innovatively optimized, the defects of lodging and stripping of the carbon nanotubes in a traditional pressing method are overcome, the stability and thermal conductivity of a thermal interface are greatly improved, and the method is particularly suitable for heat dissipation management of high-performance electronic devices.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation management of electronic devices and related materials technology, and in particular to a low thermal resistance interface structure and method for forming carbon nanotubes grown in opposite directions. Background Technology

[0002] In the thermal management of electronic devices, reducing interfacial thermal resistance is crucial for improving device performance and reliability. Carbon nanotubes, due to their high axial thermal conductivity, have become an ideal thermal interface material and have been widely studied and applied. Current technologies typically employ a method of pressing two surfaces with carbon nanotubes together, aiming to reduce interfacial thermal resistance through the contact between the carbon nanotubes. However, because carbon nanotubes are prone to collapsing and peeling during the pressing process, especially on highly uneven surfaces, the contact between the carbon nanotubes and the substrate is unstable, resulting in high interfacial thermal resistance and failing to fully utilize the thermal conductivity potential of carbon nanotubes.

[0003] To address this issue, some technical solutions attempt to reduce thermal resistance by increasing the density of carbon nanotubes or optimizing their arrangement. However, these methods often suffer from complex processes, poor controllability, and low repeatability. Furthermore, under high pressure, carbon nanotubes still tend to collapse. In addition, existing lamination techniques typically cannot achieve precise alignment of carbon nanotubes, resulting in limited contact area between them and persistently high thermal resistance.

[0004] Therefore, how to significantly reduce interfacial thermal resistance while ensuring the stability and uniform distribution of carbon nanotubes has become the technical problem to be solved by this invention. Summary of the Invention

[0005] The technical problem solved by the present invention is to address the deficiencies in the prior art by providing a low thermal resistance interface structure and method for forming carbon nanotubes through interleaved growth, thereby solving the problem of high interface thermal resistance caused by the easy collapse and peeling of carbon nanotubes during the pressing process mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A low thermal resistance interface structure formed by interleaved growth of carbon nanotubes, the thermal interface structure comprising:

[0008] At least two substrates, wherein the substrates are bonded together to form microchannels;

[0009] The microchannel contains catalysts related to carbon nanotube growth.

[0010] The microchannel contains intersecting carbon nanotubes, which form an entangled structure in the intersecting contact area to increase the contact area between the carbon nanotubes, reduce the contact distance, and lower the interfacial thermal resistance.

[0011] As a further aspect of the present invention, the phase-to-phase staggered growth of the carbon nanotubes is achieved through the following steps:

[0012] A catalyst is distributed on the surface of the substrate;

[0013] The substrate is bonded to form a bonding interface with microchannels;

[0014] A carbon source gas is introduced into the microchannel, and carbon nanotubes are grown under the action of the catalyst, thereby forming an interlaced carbon nanotube structure within the microchannel.

[0015] As a further embodiment of the present invention, the catalyst is iron, nickel, or a combination thereof.

[0016] As a further aspect of the present invention, the height of the microchannel is determined after substrate bonding, and is used to control the growth of the carbon nanotubes that are staggered in opposite directions.

[0017] As a further aspect of the present invention, the opposing carbon nanotubes have a parallel interlaced contact structure.

[0018] As a further aspect of the present invention, the interfacial thermal resistance does not exceed 1 mm. 2 K / W.

[0019] A method for growing carbon nanotubes in a staggered manner to form a low thermal resistance interface structure, the method comprising the following steps:

[0020] Catalysts for growing carbon nanotubes are distributed on a substrate on which a low thermal resistance interface is to be formed.

[0021] Silicon oxide-silicon oxide bonding is performed on the substrate to form a bonding interface with microchannels;

[0022] Carbon source gas is introduced into the microchannel, and carbon nanotubes are grown under the action of the catalyst, so that an interleaved carbon nanotube structure is formed in the microchannel, thereby achieving a low thermal resistance interface.

[0023] As a further embodiment of the present invention, the catalyst is iron, nickel, or a combination thereof, and the carbon source gas is acetylene, methane, or a combination thereof.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. Interlocking Carbon Nanotube Structure: This invention achieves an entangled structure between carbon nanotubes by interlocking carbon nanotube growth within microchannels. This structure not only increases the contact area between carbon nanotubes but also effectively shortens the contact distance between them, thereby significantly reducing interfacial thermal resistance. Compared with traditional pressing methods, the interfacial thermal resistance of this invention is significantly reduced, reaching a theoretically near-limit low thermal resistance level.

[0026] 2. Introduction of microchannel growth technology: Microchannels are formed using silica-silica bonding technology, and carbon nanotubes are grown within them. This method allows the height of the microchannels to be determined during the bonding process, thus precisely controlling the growth conditions of the opposing staggered carbon nanotubes. This method not only improves the controllability and repeatability of the manufacturing process but also significantly improves the arrangement structure of the carbon nanotubes, providing a reliable guarantee for achieving low thermal resistance interfaces.

[0027] 3. Optimized Catalyst Distribution: The catalyst distribution was optimized to ensure uniform growth of carbon nanotubes within the microchannels. Improvements in catalyst selection (e.g., iron, nickel, or combinations thereof) and their distribution promoted efficient carbon nanotube growth and enhanced the entanglement effect between nanotubes. This innovative catalyst design and distribution scheme enabled the thermal interface structure of this invention to achieve low thermal resistance while exhibiting higher mechanical and thermal stability.

[0028] 4. Reduced interfacial thermal resistance to 1mm 2 Below K / W, the method also avoids the problems of carbon nanotube collapse and peeling in traditional methods by precisely controlling the staggered growth of carbon nanotubes, significantly improving the overall performance of the thermal interface. Furthermore, the process of this invention is simple and easy to industrialize, making it particularly suitable for heat dissipation management of high-performance electronic devices.

[0029] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of the present invention when the catalyst is distributed on the substrate.

[0032] Figure 2 for Figure 1A schematic diagram of the bonding process to the substrate.

[0033] Figure 3 This is a schematic diagram of carbon nanotube growth.

[0034] Figure 4 This is a cross-sectional view of the interleaved carbon nanotubes within the microchannel.

[0035] Figure 5 This is a sample image without carbon nanotubes within the microchannel.

[0036] Figure 6 This is an image of a sample containing carbon nanotubes within a microchannel.

[0037] Figure 7 This is a diagram showing the entanglement between opposing carbon nanotubes. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Please see Figure 1 —7. In this embodiment of the invention, a low thermal resistance interface structure is formed by interleaved growth of carbon nanotubes, the thermal interface structure comprising:

[0040] At least two substrates, wherein the substrates are bonded together to form microchannels;

[0041] The microchannel contains catalysts related to carbon nanotube growth.

[0042] The microchannel contains intersecting carbon nanotubes, which form an entangled structure in the intersecting contact area to increase the contact area between the carbon nanotubes, reduce the contact distance, and lower the interfacial thermal resistance.

[0043] As a further aspect of the present invention, the phase-to-phase staggered growth of the carbon nanotubes is achieved through the following steps:

[0044] A catalyst is distributed on the surface of the substrate;

[0045] The substrate is bonded to form a bonding interface with microchannels;

[0046] A carbon source gas is introduced into the microchannel, and carbon nanotubes are grown under the action of the catalyst, thereby forming an interlaced carbon nanotube structure within the microchannel.

[0047] As a further embodiment of the present invention, the catalyst is iron, nickel, or a combination thereof.

[0048] As a further aspect of the present invention, the height of the microchannel is determined after substrate bonding, and is used to control the growth of the carbon nanotubes that are staggered in opposite directions.

[0049] As a further aspect of the present invention, the opposing carbon nanotubes have a parallel interlaced contact structure.

[0050] As a further aspect of the present invention, the interfacial thermal resistance does not exceed 1 mm. 2 K / W.

[0051] A method for growing carbon nanotubes in a staggered manner to form a low thermal resistance interface structure, the method comprising the following steps:

[0052] Catalysts for growing carbon nanotubes are distributed on a substrate on which a low thermal resistance interface is to be formed.

[0053] Silicon oxide-silicon oxide bonding is performed on the substrate to form a bonding interface with microchannels;

[0054] Carbon source gas is introduced into the microchannel, and carbon nanotubes are grown under the action of the catalyst, so that an interleaved carbon nanotube structure is formed in the microchannel, thereby achieving a low thermal resistance interface.

[0055] As a further embodiment of the present invention, the catalyst is iron, nickel, or a combination thereof, and the carbon source gas is acetylene, methane, or a combination thereof.

[0056] Example 1:

[0057] In the thermal management of high-performance electronic devices, chip stacking has gradually become the mainstream design. However, effective heat dissipation between stacked chips remains a technical challenge, especially when the gaps between chips are small and high power density needs to be maintained. Traditional thermal interface materials are insufficient to meet the requirements of low interfacial thermal resistance. In such applications, a common technique is to grow carbon nanotubes on the chip surface and connect them through lamination for heat dissipation. However, in traditional lamination methods, carbon nanotubes are prone to collapse due to uneven pressure during lamination, leading to increased interfacial thermal resistance and affecting heat dissipation efficiency. Furthermore, on highly uneven surfaces, the problem of carbon nanotube peeling is more severe, and may even lead to short circuits between chips, posing a threat to device reliability.

[0058] To address the aforementioned problems, this invention provides a method for interleaved growth of carbon nanotubes within microchannels formed by silicon oxide-silicon oxide bonding. In specific applications, a catalyst layer, such as iron or nickel, is first uniformly distributed on the target interface of stacked chips. The catalyst distribution is precisely controlled to ensure coverage of the entire contact area. Next, the two chip substrates are connected using silicon oxide-silicon oxide bonding technology, forming an interface structure with microchannels during the bonding process. The height of the microchannels is precisely controlled by the bonding process to ensure that the subsequently grown carbon nanotubes can form a stable structure within the microchannels.

[0059] After forming the microchannels, a carbon source gas, such as acetylene or methane, is introduced into the microchannels. With the aid of a catalyst distributed on the substrate surface, carbon nanotubes grow in opposite directions within the microchannels. Since the carbon nanotubes grow from two opposing directions, when they meet within the microchannels, they form an interlaced and entangled structure. This interlaced growth method effectively avoids the collapse and delamination problems caused by uneven pressure in traditional pressing methods. Simultaneously, due to the precise control of the microchannel height, the carbon nanotubes can achieve a parallel and interlaced arrangement in the contact area, thereby significantly increasing the contact area between the carbon nanotubes, reducing the contact distance, and resulting in a significant reduction in interfacial thermal resistance.

[0060] Through the above steps, the technical solution of this invention has been successfully applied to the heat dissipation management of stacked chips, significantly reducing the inter-chip thermal resistance to 1mm. 2 Thermal resistance values ​​below K / W. Compared to traditional technologies, this invention not only improves heat dissipation efficiency but also enhances the reliability and stability of the entire device, exhibiting superior performance, especially under high power density and long-term operating conditions. This embodiment verifies the significant advancements of this invention in practical applications, solves key problems existing in the prior art, and fully demonstrates the innovation and practicality of this invention.

[0061] Example 2:

[0062] In the thermal design of high-frequency, high-speed chips, as chip operating frequencies and power densities increase, traditional thermal interface materials are no longer sufficient to meet the requirements for low interfacial thermal resistance. Especially in some high-density packages, the thermal interface between the chip and the heatsink becomes extremely critical; even slight mishandling can lead to overheating and device failure. Traditional solutions typically involve growing carbon nanotubes on the surfaces of the chip and heatsink, then achieving thermal bonding through mechanical pressing. However, in this method, carbon nanotubes are prone to collapsing and peeling under pressure, resulting in ineffective reduction of interfacial thermal resistance and severely impacting heat dissipation performance.

[0063] To address this issue, this invention proposes a technique for growing carbon nanotubes in a staggered, inter-phase manner within microchannels. In specific applications, firstly, a layer of iron or nickel catalyst is uniformly distributed on the contact surface between a high-frequency, high-speed chip and a corresponding heat sink. Then, the chip and the heat sink substrate are connected using silicon oxide-silicon oxide bonding technology to form an interface structure with microchannels. By precisely controlling the bonding process, the height of the microchannels is ensured to meet the subsequent growth requirements of the carbon nanotubes.

[0064] After the microchannels are formed, a carbon source gas, such as methane or acetylene, is introduced into them, causing the carbon nanotubes to grow from opposite directions of the chip and the heat sink under the action of a catalyst. When the carbon nanotubes meet within the microchannels, they form an interlaced and entangled structure. This entangled structure effectively increases the contact area between the carbon nanotubes, reduces the contact distance between them, and significantly lowers the interfacial thermal resistance.

[0065] The above technical solutions, when applied to the heat dissipation management of high-frequency, high-speed chips, can significantly reduce the interfacial thermal resistance between the chip and the heat sink, achieving the theoretically extremely low interfacial thermal resistance requirement, even below 1mm. 2 K / W. This not only improves the chip's heat dissipation efficiency but also avoids the heat dissipation failure problem caused by carbon nanotube collapse in traditional lamination methods. After applying the technical solution of this invention, the operational stability of high-frequency, high-speed chips under high power density is greatly improved, extending the device's lifespan.

[0066] Example 3:

[0067] In existing technologies, carbon nanotubes possess high axial thermal conductivity, making them a promising candidate for reducing interfacial thermal resistance as a thermal interface material. Previous studies compared pressing a substrate without carbon nanotubes onto the surface of another substrate with carbon nanotubes with pressing two substrates with carbon nanotubes face-to-face. Results showed that pressing two substrates with carbon nanotubes face-to-face exhibited lower interfacial thermal resistance. This indicates that the contact thermal resistance between carbon nanotubes is lower than the interfacial thermal resistance between the carbon nanotubes and the pressed surface. However, limited by the contact pattern and ratio between carbon nanotubes, the interfacial thermal resistance achieved by pressing two substrates with carbon nanotubes face-to-face is still higher than the theoretically achievable extremely low interfacial thermal resistance using carbon nanotubes as a thermal interface material. Furthermore, during compression deformation, carbon nanotubes are prone to collapsing when encountering surfaces with significant height differences. These collapsed, blocky carbon nanotubes can detach from the growth surface, failing to effectively reduce interfacial thermal resistance. In the case of heat dissipation between stacked chip layers, this also increases the risk of short circuits with micro-soldering points.

[0068] This invention employs a method of growing carbon nanotubes in opposite directions within bonded microchannels to achieve parallel staggered contact of carbon nanotubes and reduce interfacial thermal resistance.

[0069] Specifically, firstly, catalysts for growing carbon nanotubes (such as...) are distributed at the interface where it is necessary to reduce contact thermal resistance. Figure 1 Then bond the substrate (e.g.) Figure 2 Finally, carbon nanotubes (such as...) are grown. Figure 3 ).

[0070] Interwoven carbon nanotubes formed during growth (e.g.) Figure 4 This can significantly reduce the thermal resistance between interfaces. Figure 5 and Figure 6 The temperature distribution of the sample, captured from above, using an infrared camera when heating the sample with an S-shaped heating resistor. Figure 5 The results show that, without the growth of carbon nanotubes, heat is evenly distributed in the resistance wire region and conducted to the bottom of the sample. Figure 6 The results show that when carbon nanotubes are grown in an interleaved manner within the microchannel, heat is concentrated and conducted to the bottom of the sample because the thermal resistance of the carbon nanotube regions is significantly lower than that of the bonding regions. Therefore, the thermal resistance of the interleaved carbon nanotubes is significantly lower than that of the bonding regions on both sides. The calculated contact thermal resistance of the interleaved carbon nanotube interface is approximately 1 mm. 2 K / W, lower than the contact thermal resistance achievable by the compression method by 4mm. 2 K / W.

[0071] Figure 7 The study demonstrates the intertwined structure formed between staggered carbon nanotubes. This structure effectively increases the contact area between carbon nanotubes and reduces the distance between them, thereby achieving low interfacial thermal resistance.

[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A low thermal resistance interface structure formed by the interleaved growth of carbon nanotubes, characterized in that: The thermal interface structure includes: At least two substrates, wherein the substrates are bonded together to form microchannels; The microchannel contains catalysts related to carbon nanotube growth. The microchannel contains intersecting carbon nanotubes, which form an entangled structure in the intersecting contact area to increase the contact area between the carbon nanotubes, reduce the contact distance, and lower the interfacial thermal resistance.

2. The low thermal resistance interface structure and method for forming carbon nanotubes through interleaved growth according to claim 1, characterized in that, The staggered growth of the carbon nanotubes is achieved through the following steps: A catalyst is distributed on the surface of the substrate; The substrate is bonded to form a bonding interface with microchannels; A carbon source gas is introduced into the microchannel, and carbon nanotubes are grown under the action of the catalyst, thereby forming an interlaced carbon nanotube structure within the microchannel.

3. The low thermal resistance interface structure and method for forming carbon nanotubes through interleaved growth according to claim 1, characterized in that, The catalyst is iron, nickel, or a combination thereof.

4. The low thermal resistance interface structure and method for forming carbon nanotubes through interleaved growth according to claim 1, characterized in that, The height of the microchannel is determined after substrate bonding and is used to control the growth of the phase-interlaced carbon nanotubes.

5. The low thermal resistance interface structure and method for forming carbon nanotubes through interleaved growth according to claim 1, characterized in that, The opposing carbon nanotubes have a parallel interlaced contact structure.

6. The low thermal resistance interface structure and method for forming carbon nanotubes through interleaved growth according to claim 1, characterized in that, The interfacial thermal resistance does not exceed 1 mm. 2 K / W.

7. A method for growing carbon nanotubes in a staggered manner to form a low thermal resistance interface structure, characterized in that, The method includes the following steps: Catalysts for growing carbon nanotubes are distributed on a substrate on which a low thermal resistance interface is to be formed. Silicon oxide-silicon oxide bonding is performed on the substrate to form a bonding interface with microchannels; Carbon source gas is introduced into the microchannel, and carbon nanotubes are grown under the action of the catalyst, so that an interleaved carbon nanotube structure is formed in the microchannel, thereby achieving a low thermal resistance interface.

8. The low thermal resistance interface structure and method for forming carbon nanotubes through interleaved growth according to claim 7, characterized in that, The catalyst is iron, nickel, or a combination thereof, and the carbon source gas is acetylene, methane, or a combination thereof.

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