Three-dimensional (3D) thermal joints including rheology-controlled thermal interface materials (TIMs)

Abstract

This invention provides a method for filling the gap between a heat-generating element and a heat-sinking element using a thermal interface material (TIM) with good thermal conductivity, as well as a three-dimensional thermal joint and an electronic device. [Solution] Three-dimensional (3D) thermal joints are formed using TIMs, etc., which are based on metal amalgam, low-melting-point alloys, and liquid metals, and fillers made of refractory materials are mixed in, thereby controlling the rheology of these materials to a desired range.

Description

[Technical Field]

[0001] This disclosure generally relates to three-dimensional (3D) thermal joints, including thermal interface materials (TIMs), such as metal amalgams, low-melting-point alloys, liquid metals, and rheology-controlled thermal TIMs. [Background technology]

[0002] This section provides background information relating to this disclosure that is not necessarily prior art. Semiconductors, integrated circuit packages, transistors, and other electrical components typically have a pre-designed operating temperature. Ideally, this pre-designed temperature is close to the ambient air temperature. However, the operation of electrical components generates heat. If this heat is not dissipated, electrical components may operate at temperatures significantly higher than their normal or desired operating temperature. Such excessive temperatures can adversely affect the operating characteristics of electrical components and the operation of associated devices.

[0003] To avoid, or at least mitigate, unfavorable operating characteristics due to heat generation, heat must be removed, for example, by conducting heat from operating electrical components to a heatsink. The heatsink can then be cooled by conventional convection and / or radiation techniques. During conduction, heat can be transferred from operating electrical components to the heatsink by direct surface contact between the electrical components and the heatsink, and / or by contact between the electrical components and the heatsink surface via an intermediate medium or TIM. Compared to filling gaps with air, which has relatively low thermal conductivity, TIM can be used to fill gaps between heat transfer surfaces to improve heat transfer efficiency. [Modes for carrying out the invention]

[0004] Detailed description of the invention Next, exemplary embodiments will be described in more detail with reference to the attached drawings. As recognized herein, high-performance processors may have multiple heights due to their 2D, 2.5D, 3D, chiplet, and other designs, which makes heat dissipation more difficult as it results in multiple different heights with respect to these components. Having recognized the above, exemplary embodiments of methods for forming three-dimensional (3D) thermal joints using rheology-controlled thermal interface materials (TIMs), such as metal amalgams, low-melting-point alloys (e.g., gallium-based liquid metal alloys, low-melting-point alloys having a melting point of 160°C or less, and other low-melting-point alloys), and liquid metals (e.g., liquid metals that can form thermal joints at near room temperature, and liquid metals that can form thermal joints at temperatures of about 19°C or less).

[0005] In exemplary embodiments, a three-dimensional (3D) thermal joint comprises a rheology-controlled thermal interface material (TIM). A 3D thermal joint can be used to fill gaps between heat sources in electronic devices and other components. For example, a 3D thermal joint can be used to fill gaps between multiple components / heat sources of varying heights (e.g., integrated circuit (IC) components of varying heights, 2D processors, 2.5D processors, 3D processors, chiplet segmented processors, and other components having multiple heights) and a heat removal / dissipation component (e.g., a heat sink, heat spreader, heat pipe, vapor chamber, water block, device outer casing, housing, chassis, etc.). In such exemplary embodiments, a 3D thermal joint formed by the rheology-controlled thermal interface material is three-dimensionally molded in such a way that the 3D thermal joint will have multiple different heights or thicknesses, determined by the size of the gaps between the heat removal / dissipation component and the multiple components / heat sources of varying heights that are filled by the rheology-controlled thermal interface material.

[0006] In exemplary embodiments, a 3D thermal joint formed or defined by a rheology-controlled thermal interface material (e.g., a metal amalgam, low-melting-point alloy, liquid metal, etc.) is used to fill the gap between a multi-height integrated circuit (IC) (broadly speaking, a heat source or component) and a heat sink (broadly speaking, a heat removal and dissipation component). The 3D thermal joint establishes or defines an efficient thermal path for conducting heat from the multi-height integrated circuit to the heat sink, allowing heat to flow from the multi-height integrated circuit to the heat sink through the thermal joint during the operation of the electronic device, thereby reducing the temperature of the multi-height integrated circuit. The rheology-controlled thermal interface material can be configured such that the thereby defined 3D thermal joint has a high thermal conductivity of 10 watts / meter·Kelvin (W / mK) or more and a bond line thickness (BLT) in the range of about 3 micrometers to about 3 millimeters (mm).

[0007] Exemplary methods include applying rheology-controlled thermal interface materials (e.g., metal amalgams, low-melting-point alloys, liquid metals, etc.) to heat sinks (broadly speaking, heat removal and dissipation components), multi-height integrated circuits (ICs) (broadly speaking, heat sources or components), or both heat sinks and multi-height integrated circuits. For example, liquid metal may be applied to heat sinks, multi-height integrated circuits (ICs) (broadly speaking, heat sources or components), or both heat sinks and multi-height integrated circuits.

[0008] In exemplary embodiments, the rheology-controlled thermal interface material includes a liquid metal configured to form a 3D thermal joint at near room temperature (e.g., room temperature of about 20°C to 22°C, temperature of about 19°C, etc.). In such exemplary embodiments, the liquid metal may be applied to a heat sink (broadly speaking, a heat removal and dissipation component), a multi-height integrated circuit (IC) (broadly speaking, a heat source or component), or both a heat sink and a multi-height integrated circuit. Advantageously, the liquid metal does not require heating to form a 3D thermal joint filling the gap between the multi-height integrated circuit and the heat sink. The 3D thermal joint formed by the liquid metal is three-dimensionally shaped in such a way that the 3D thermal joint will have multiple different heights or thicknesses, determined by the size of the gap filled by the liquid metal between the heat sink and the IC component of varying heights.

[0009] In other exemplary embodiments, the rheology-controlled thermal interface material includes a low-melting-point alloy (e.g., gallium-based liquid metal alloys, low-melting-point alloys having a melting point of 160°C or less, and other low-melting-point alloys). In such exemplary embodiments, the low-melting-point alloy may be applied to a heat sink (broadly speaking, a heat removal and dissipation component), a multi-height integrated circuit (IC) (broadly speaking, a heat source or component), or both the heat sink and the multi-height integrated circuit. The low-melting-point alloy may then be heated to its melting point (e.g., a melting point of 160°C or less), and as a result, the molten low-melting-point alloy flows into the gap between the multi-height integrated circuit and the heat sink, filling the gap. After the molten low-melting-point alloy cools and resolidifies, it forms a 3D thermal joint that fills the gap between the multi-height integrated circuit and the heat sink. A 3D thermal joint formed from a low-melting-point alloy is three-dimensionally shaped in such a way that the 3D thermal joint will have multiple different heights or thicknesses, determined by the size of the gap filled by the liquid metal between the heat sink and the IC components of varying heights.

[0010] In some exemplary embodiments, a heat sink (broadly speaking, a heat removal and dissipation component) can be pre-assembled to a multi-height integrated circuit (IC) (broadly speaking, a heat source or component) of an electronic device before applying a rheology-controlled thermal interface material. In such exemplary embodiments, the rheology-controlled thermal interface material (e.g., a metal amalgam, a low-melting-point alloy, a liquid metal, etc.) is applied (e.g., by dispensing) to fill the gap between the pre-assembled heat sink and the multi-height integrated circuit. For example, a liquid metal may be dispensed to fill the gap between the pre-assembled heat sink and the multi-height integrated circuit. Alternatively, for example, a molten low-melting-point alloy may be dispensed to fill the gap between the pre-assembled heat sink and the multi-height integrated circuit.

[0011] In some exemplary embodiments, the rheology-controlled thermal interface material may include a preform having a pre-formed shape, pattern, thickness, etc. During the assembly of a heat sink (broadly speaking, a heat removal / dissipation component) to a multi-height integrated circuit (IC) (broadly speaking, a heat source or component) of an electronic device, the preform of the rheology-controlled thermal interface material can be positioned or sandwiched between the heat sink and the multi-height integrated circuit (IC). The preform of the rheology-controlled thermal interface material can then be heated (for example, to a melting point of 160°C or less) to allow the molten rheology-controlled thermal interface material to flow into the gap between the multi-height integrated circuit and the heat sink, filling the gap. After the molten rheology-controlled thermal interface material cools and re-solidifies, the rheology-controlled thermal interface material fills the gap between the multi-height integrated circuit and the heat sink. A 3D thermal joint formed by a rheology-controlled thermal interface material is three-dimensionally shaped in such a way that the 3D thermal joint will have multiple different heights or thicknesses, determined by the size of the gaps filled by the rheology-controlled thermal interface material between the heat sink and IC components of varying heights.

[0012] As merely one example, exemplary embodiments disclosed herein may include rheology-controlled thermal interface materials including metal amalgams containing non-refractory filler particles (e.g., non-refractory metal filler particles) as disclosed in U.S. Patent Application Publication No. 2025 / 0257432, published on 14 August 2025 and incorporated herein in its entirety by reference. However, other exemplary embodiments include other rheology-controlled thermal interface materials other than metal amalgams containing non-refractory filler particles, and other methods for rheology-controlling thermal interface materials other than the use of non-refractory filler particles; therefore, the metal amalgams containing non-refractory filler particles disclosed in U.S. Patent Application Publication No. 2025 / 0257432 are merely examples. Accordingly, embodiments of this disclosure should not be limited to metal amalgams containing non-refractory filler particles.

[0013] In exemplary embodiments, 3D thermal joints are formed by using a rheology-controlled thermal interface material (TIM) containing non-refractory (not corrosion-resistant) metal fillers incorporated into the TIM (e.g., metal amalgam, liquid metal, low-melting-point alloy) to obtain a stable suspension, with viscosity controlled based on the total amount of filler added without sacrificing the thermal properties of the TIM application. In such exemplary embodiments, the rheology-controlled TIM remains in place (e.g., does not move, flow, discharge, or detach) during thermal reliability tests, such as vertical reliability tests in thermal shock from -40°C to 150°C over 1000 cycles. Furthermore, the rheology-controlled TIM can be processed on a substrate in a controlled manner by rheology control, which allows for isotropic spreading of the TIM when pressed between heat transfer surfaces of an electronic device or between substrates, for example, when compressed between a heat source and a heat removal / dissipation component. When rheologically controlled TIM is pressed between heat transfer surfaces or between substrates, isotropic spreading control occurs (e.g., material movement is limited, reduced, or not), which is a processing advantage in the TIM field because the material is sandwiched during application and the surface coverage of the TIM is important. Conventional liquid metal diffusion anisotropy makes processing difficult.

[0014] In exemplary embodiments, 3D thermal joints are formed using a rheology-controlled thermal interface material (TIM) containing a metal alloy (e.g., a low-viscosity gallium-indium-tin liquid metal alloy) filled with non-refractory copper and nickel particles, which enables stable and homogeneous suspension, resulting in increased viscosity, rheology control based on the total amount of filler added, stable wettability of various surfaces, and diffusion control in workability and reliability. These properties are enhanced without sacrificing the thermal performance of the rheology-controlled TIM after the copper and nickel particles are mixed into the metal alloy. As just one example, the rheology-controlled TIM may be filled or mixed with about 1 wt% to about 10 wt% (e.g., about 6 wt%) of nickel and copper, resulting in a rheology-controlled TIM having an increased or elevated viscosity (e.g., a custard-like consistency). Furthermore, as just one example, when the rheology-controlled TIM contained approximately 6 wt% nickel and copper, the rheology-controlled TIM had a thermal conductivity in the range of 28 W / mK to 30 W / mK.

[0015] In exemplary embodiments, the 3D thermal joint is formed by using a rheology-controlled thermal interface material (TIM) containing a metal amalgam containing nickel and copper, such that the nickel-to-copper ratio by weight percentage (wt%) is in the range of about 1:1 to about 5:1. For example, in exemplary embodiments, a nickel-to-copper ratio of about 2:1 can be maintained, which achieves a stable and homogeneous metal amalgam suspension. In exemplary embodiments, the metal amalgam is filled or mixed with nickel and copper such that the total amount of nickel and copper added ranges from about 1 wt% to about 10 wt% (e.g., 4 wt%, 6 wt%, 8 wt%, etc.). In such exemplary embodiments, the filler-compounded metal amalgam has a thermal conductivity of over 15 W / mK (e.g., 28 W / mK to 30 W / mK, etc.), and about 4 mm². 2 Less than kW, but approximately 1 mm 2It may have a thermal resistance of K / W or more, and a viscosity of 2800 Pascal seconds or less at a shear rate of 0.5 / s and 75 Pascal seconds or less at a shear rate of 5 / s.

[0016] As merely one example, one exemplary embodiment includes a 3D thermal joint formed by using a filler-compounded metal amalgam containing a gallium-indium-tin liquid metal alloy filled or mixed with about 6 wt% nickel and copper. In this example, the filler-compounded metal amalgam has a thermal conductivity in the range of about 28 W / mK to about 30 W / mK and about 4 mm 2 It had a contact thermal resistance of less than kW / W, a strain rate of 5 / s viscosity (in air) in the range of about 28 to about 33 Pascal seconds, and a strain rate of 0.5 / s viscosity (in air) at about 407 Pascal seconds. From consistency observations, the filler-containing metal amalgam had a custard-like appearance. The specific alloys, 6 wt% additive amounts, thermal conductivity, thermal resistance, and viscosity presented in this paragraph and elsewhere are merely examples, and other exemplary embodiments may be configured differently, for example, with different metal alloys (e.g., another low-melting-point alloy having a melting point below 160°C), different liquid metals, higher or lower wt% additive amounts, higher or lower thermal conductivity, higher or lower thermal resistance, and / or higher or lower viscosity.

[0017] As merely another example, another exemplary embodiment includes a 3D thermal joint formed by using a filler-compounded metal amalgam containing a gallium-indium-tin liquid metal alloy filled or mixed with about 8 wt% nickel and copper. In this example, the filler-compounded metal amalgam has a thermal conductivity in the range of about 28 W / mK to about 30 W / mK and about 4 mm 2It had a contact thermal resistance of less than kW / W, a strain rate of 5 / s viscosity (in air) in the range of about 60 to about 65 Pascal seconds, and a strain rate of 0.5 / s viscosity (in air) at about 1997 Pascal seconds. Consistency observations and comparisons showed that the filler-containing metal amalgam had the consistency of a coatable paste. The specific alloys, 8 wt% additive amounts, thermal conductivity, thermal resistance, and viscosity presented in this paragraph and elsewhere are merely examples, and other exemplary embodiments may be configured differently, for example, with different metal alloys (e.g., another low-melting-point alloy having a melting point below 160°C), different liquid metals, higher or lower wt% additive amounts, higher or lower thermal conductivity, higher or lower thermal resistance, and / or higher or lower viscosity.

[0018] Furthermore, and this is merely one example, a further exemplary embodiment includes a 3D thermal joint formed by using a filler-compounded metal amalgam containing a gallium-indium-tin liquid metal alloy filled or mixed with about 10 wt% nickel and copper. In this example, the filler-compounded metal amalgam has a thermal conductivity in the range of about 28 W / mK to about 30 W / mK and about 4 mm 2 It had a contact thermal resistance of less than K / W, a strain rate of 5 / s viscosity (in air) in the range of about 60 Pascals-seconds to about 65 Pascals-seconds, and a strain rate of 0.5 / s viscosity (in air) at about 2595 Pascals-seconds. Consistency observations and comparisons showed that the filler-containing metal amalgam had the consistency of a thick, applicable paste. The specific alloys, 10 wt% additive amounts, thermal conductivity, thermal resistance, and viscosity presented in this paragraph and elsewhere are merely examples, and other exemplary embodiments may be configured differently, for example, with different metal alloys (e.g., another low-melting-point alloy having a melting point below 160°C), different liquid metals, higher or lower wt% additive amounts, higher or lower thermal conductivity, higher or lower thermal resistance, and / or higher or lower viscosity.

[0019] As illustrated by the above example, the final consistency of a rheology-controlled TIM containing a metal amalgam mixed with non-refractory filler particles is based on the total amount of metal filler added. In exemplary embodiments, the nickel-to-copper ratio by weight percentage (wt%) is in the range of about 1:1 to about 5:1. For example, a nickel-to-copper ratio of about 2:1 may be maintained in the filler-compounded metal amalgam, which achieves a stable and homogeneous metal amalgam suspension. Even if the consistency of the metal amalgam changes with the amount of metal filler added, the thermal performance remains substantially the same, for example, with a thermal conductivity of over 15 W / mK (e.g., in the range of about 28 W / mK to about 30 W / mK, etc.) and about 4 mm 2 Less than kW, but approximately 1 mm 2 The thermal resistance is greater than K / W. The above examples illustrate a range of compositions in which enhanced effects have been observed due to the presence of non-refractory fillers (nickel and copper). In these exemplary compositions, when pressurized between two heat transfer surfaces or substrates, increased viscosity and enhanced spreading control (e.g., material movement is limited, reduced, or absent) are observed, but no change in thermal properties is observed. This is beneficial in this field, as other systems containing rheologically controlled liquid metals sacrifice thermal performance when rheological and spreading properties are controlled.

[0020] Accordingly, the exemplary embodiments disclosed herein can provide one or more (but not necessarily one or all) of the following advantages. For example, conventional polymer composite-based TIMs are limited in how thin the bond line can be based on the particles used to improve thermal conductivity. Conventionally, particles are larger than 10 μm or even larger to have high thermal conductivity. For example, for a composite-based TIM to achieve a thermal conductivity of 10 W / mK, particles larger than 25 μm are required, but particles larger than 25 μm result in a minimum bond line of 25 μm or more. Advantageously, the exemplary embodiments disclosed herein include a rheology-controlled TIM that can achieve a bond line thickness of 3 μm or less while still having a thermal conductivity of 10 W / mK or higher. Compared with other conventional liquid metals, the rheology-controlled liquid metal used to form a 3D thermal joint in the exemplary embodiments disclosed herein can maintain a three-dimensional shape with a maximum thickness of up to about 3 mm without the rheology-controlled liquid metal falling out of the thermal joint. In contrast, conventional, rheologically uncontrolled liquid metals self-level and move away from thermal joints.

[0021] The exemplary embodiments disclosed herein advantageously include rheologically controlled TIMs (e.g., metal amalgams, low melting point alloys, liquid metals, etc.), which do not require sacrificing thermal conductivity and thermal resistance to maintain rheological and diffusion control (e.g., limiting or preventing material migration, etc.). Since rheologically controlled TIMs (e.g., metal amalgams, liquid metals, low melting point alloys, etc.) can wet surfaces as they are, the exemplary embodiments disclosed herein do not require any solder preforms or surface treatments to maintain the TIM in place and / or to wet the surface. In exemplary embodiments, the rheologically controlled TIM does not contain any organic solvents and / or organic compounds that may reduce wettability and / or result in void formation from outgassing during thermal cycling. In conventional filler-blended liquid metal all-metal amalgam systems, maintaining a stable suspension of particles in the liquid metal is a significant challenge. In the exemplary embodiments disclosed herein, the rheologically controlled TIM remains a stable suspension after particles are mixed into the TIM (e.g., metal amalgam, liquid metal, low melting point alloy, etc.).

[0022] An exemplary method is disclosed that includes using a rheologically controlled thermal interface material to form a three-dimensional thermal joint that fills a plurality of gaps of varying distances between a first heat transfer surface and a second heat transfer surface of an electronic device, allowing heat to flow through the three-dimensional thermal joint between the first heat transfer surface and the second heat transfer surface.

[0023] In an exemplary embodiment, the three-dimensional thermal joint formed by the rheologically controlled thermal interface material is three-dimensionally shaped to have a plurality of different heights determined by the plurality of gaps filled by the rheologically controlled thermal interface material between a first heat transfer surface and a second heat transfer surface of an electronic device.

[0024] In an exemplary embodiment, the first and / or second heat transfer surfaces are defined by one or more of a heat removal / dissipation structure, a heat source of an electronic device, a component of a solid state drive, and / or a board level shield.

[0025] In an exemplary embodiment, the first heat transfer surface is defined by a heat removal / dissipation component such as a heat sink, a heat spreader, a heat pipe, a vapor chamber, a water block, a device outer case, a housing, or a chassis. And the second heat transfer surface is defined by a heat source of an electronic device, such as an integrated circuit (e.g., an integrated circuit with multiple heights, etc.) or other components of an electronic device.

[0026] In an exemplary embodiment, the first heat transfer surface is defined by a heat removal / dissipation component. The second heat transfer surface is defined by heat sources with multiple heights. And the three-dimensional thermal joint formed by the rheology-controlled thermal interface material has a plurality of different heights determined by a plurality of gaps filled between the heat removal / dissipation component and the heat sources with multiple heights by the rheology-controlled thermal interface material, so that it is shaped three-dimensionally. During operation of the electronic device, heat can flow from the heat sources with multiple heights through the three-dimensional thermal joint to the heat removal / dissipation component, thereby reducing the temperature of the heat sources with multiple heights. In such exemplary embodiments, the heat removal / dissipation component can include a heat sink, a heat spreader, a heat pipe, a vapor chamber, a water block, a device outer case, a housing, a chassis, and the like. And the heat sources with multiple heights can include integrated circuits with multiple heights, 2D processors, 2.5D processors, 3D processors, chiplet segmented processors, and the like.

[0027] In an exemplary embodiment, a first heat transfer surface is defined by a heat sink. A second heat transfer surface is defined by a multi-height integrated circuit. A three-dimensional thermal joint formed from a rheology-controlled thermal interface material is three-dimensionally shaped to have multiple different heights, determined by multiple gaps between the heat sink and the multi-height integrated circuit that are filled by the rheology-controlled thermal interface material. During operation of the electronic device, heat can flow from the multi-height integrated circuit through the three-dimensional thermal joint to the heat sink, thereby lowering the temperature of the multi-height integrated circuit. The multi-height integrated circuit may include a 2D processor, a 2.5D processor, a 3D processor, a chiplet segmented processor, and the like.

[0028] In exemplary embodiments, a first heat transfer surface is defined by a first component of an electronic device. A second heat transfer surface is defined by a second component of an electronic device. The method also includes applying a rheology-controlled thermal interface material to the first and / or second heat transfer surfaces of the electronic device, and subsequently assembling the first component with the second component.

[0029] In an exemplary embodiment, a first heat transfer surface is defined by a first component of the electronic device. A second heat transfer surface is defined by a second component of the electronic device. The method also includes assembling the first component to the second component and subsequently applying a rheology-controlled thermal interface material to fill a plurality of gaps of varying distances between the first and second heat transfer surfaces of the electronic device.

[0030] In exemplary embodiments, the rheology-controlled thermal interface material includes a preform. The method also includes placing the preform of the rheology-controlled thermal interface material between a first heat transfer surface and a second heat transfer surface; heating the preform of the rheology-controlled thermal interface material to allow the molten rheology-controlled thermal interface material to flow into a plurality of gaps of varying distances between the first and second heat transfer surfaces to fill the plurality of gaps of varying distances; and allowing the molten rheology-controlled thermal interface material to cool and re-solidify, thereby forming a three-dimensional thermal joint that fills a plurality of gaps of varying distances between the first and second heat transfer surfaces of an electronic device.

[0031] In exemplary embodiments, the rheology-controlled thermal interface material includes a liquid metal. The method also includes applying the liquid metal to a first and / or second heat transfer surface, allowing the liquid metal to flow into a plurality of gaps of varying distances between the first and second heat transfer surfaces to fill the plurality of gaps of varying distances, and solidifying the liquid metal to form a three-dimensional thermal joint that fills the plurality of gaps of varying distances between the first and second heat transfer surfaces of the electronic device. In such exemplary methods, the step or process of solidifying the liquid metal may include solidifying the liquid metal at substantially room temperature. Therefore, the liquid metal does not require heating to form a three-dimensional thermal joint that fills the plurality of gaps of varying distances between the first and second heat transfer surfaces of the electronic device.

[0032] In an exemplary embodiment, the rheology-controlled thermal interface material comprises a metal alloy. The method comprises: applying the metal alloy to a first heat transfer surface and / or a second heat transfer surface; heating the metal alloy to cause the molten metal alloy to flow into a plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface, filling the plurality of gaps of varying distances; and allowing the molten metal alloy to cool and resolidify, thereby forming a three-dimensional thermal joint that fills the plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface of an electronic device. In such exemplary methods, the low-melting-point alloy may comprise a gallium-based liquid metal alloy, and / or the low-melting-point alloy may have a melting point of about 160°C or lower.

[0033] In an exemplary embodiment, the rheology-controlled thermal interface material comprises a metal amalgam having non-refractory filler particles dispersed therein. The non-refractory filler particles may comprise non-refractory (non-corrosion-resistant) metallic filler particles. For example, the non-refractory filler particles may comprise copper and nickel. The metal amalgam may comprise from about 1 percent to about 10 percent of nickel and copper by weight percent (wt%) and / or volume percent (vol%), within a nickel:copper ratio ranging from about 1:1 to about 5:1, or at a nickel:copper ratio of about 2:1 by weight percent (wt%) and / or volume percent (vol%). A metal amalgam comprising nickel and copper has a thermal conductivity greater than 15 W / mK, about 4 mm 2 K / W but less than about 1 mm 2 K / W or higher thermal resistance, and may have a viscosity of no more than 2800 Pascal-seconds at a shear rate of 0.5 / s and no more than 75 Pascal-seconds at a shear rate of 5 / s.

[0034] In an exemplary embodiment, the rheology-controlled thermal interface material comprises a gallium-based liquid metal including copper particles and nickel particles. In exemplary embodiments, the gallium-based liquid metal includes a low-viscosity gallium-indium-tin liquid metal alloy mixed with copper and nickel particles, thereby providing a stable, homogeneous suspension resulting in increased viscosity of the low-viscosity gallium-indium-tin liquid metal alloy, and / or rheological control based on the total amount of filler particles added, stable wettability of various surfaces, limitation or prevention of material migration, and diffusion control in workability and reliability, without sacrificing thermal performance after the copper and nickel particles are mixed into the low-viscosity gallium-indium-tin liquid metal alloy.

[0035] In exemplary embodiments, the rheology-controlled thermal interface material does not contain any organic solvents and / or organic compounds that may reduce wettability and / or lead to void formation from gas release during thermal cycling.

[0036] In exemplary embodiments, the rheology-controlled thermal interface material does not contain any silicone and / or polymer components that may reduce thermal conductivity.

[0037] In exemplary embodiments, the rheology-controlled thermal interface material consists solely of metal. In exemplary embodiments, the rheology-controlled thermal interface material includes a gallium-indium-tin liquid metal alloy containing copper and nickel, such that the gallium-indium-tin liquid metal alloy contains a nickel:copper ratio in the range of about 1:1 to about 5:1 in weight percent (wt%) and / or volume percent (vol%).

[0038] Furthermore, exemplary embodiments of three-dimensional thermal joints formed by the methods disclosed herein are also disclosed herein. In an exemplary embodiment, a first heat transfer surface is defined by a heat removal / dissipation component. A second heat transfer surface is defined by heat sources of multiple heights. A three-dimensional thermal joint formed from a rheology-controlled thermal interface material is three-dimensionally shaped to have multiple different heights, determined by multiple gaps filled by the rheology-controlled thermal interface material between the heat removal / dissipation component and the heat sources of multiple heights. During the operation of the electronic device, heat can flow from the heat sources of multiple heights through the three-dimensional thermal joint to the heat removal / dissipation component, thereby lowering the temperature of the heat sources of multiple heights. In such an exemplary embodiment, the heat removal / dissipation component may include a heat sink, heat spreader, heat pipe, vapor chamber, water block, device outer case, housing, chassis, etc. The heat sources of multiple heights may include multi-height integrated circuits, 2D processors, 2.5D processors, 3D processors, chiplet segmented processors, etc.

[0039] In an exemplary embodiment, a first heat transfer surface is defined by a heat sink. A second heat transfer surface is defined by a multi-height integrated circuit. A three-dimensional thermal joint formed from a rheology-controlled thermal interface material is three-dimensionally shaped to have multiple different heights, determined by multiple gaps filled by the rheology-controlled thermal interface material between the heat sink and the multi-height integrated circuit. During operation of the electronic device, heat can flow from the multi-height integrated circuit through the three-dimensional thermal joint to the heat sink, thereby lowering the temperature of the multi-height integrated circuit. In such an exemplary embodiment, the multi-height integrated circuit may include a 2D processor, a 2.5D processor, a 3D processor, a chiplet segmented processor, and the like.

[0040] Furthermore, exemplary embodiments of electronic devices including a three-dimensional thermal joint formed by the method disclosed herein are also disclosed. In an exemplary embodiment, the electronic device includes a first heat transfer surface defined by a heat removal / dissipation component and a second heat transfer surface defined by heat sources of multiple heights. The three-dimensional thermal joint is formed from a rheology-controlled thermal interface material. The three-dimensional thermal joint is three-dimensionally molded to have multiple different heights, determined by multiple gaps filled by the rheology-controlled thermal interface material between the heat removal / dissipation component and the heat sources of multiple heights. During the operation of the electronic device, heat can flow from the heat sources of multiple heights through the three-dimensional thermal joint to the heat removal / dissipation component, thereby lowering the temperature of the heat sources of multiple heights. In such an exemplary embodiment, the heat removal / dissipation component may include a heat sink, heat spreader, heat pipe, vapor chamber, water block, device outer case, housing, chassis, etc. The heat sources of multiple heights may include multi-height integrated circuits, 2D processors, 2.5D processors, 3D processors, chiplet segmented processors, etc.

[0041] In an exemplary embodiment, the electronic device includes a first heat transfer surface defined by a heat sink and a second heat transfer surface defined by a plurality of height integrated circuits. The three-dimensional thermal joint is formed by a rheology-controlled thermal interface material. The three-dimensional thermal joint is three-dimensionally molded to have a plurality of different heights, determined by a plurality of gaps filled by the rheology-controlled thermal interface material between the heat sink and the plurality of height integrated circuits. During operation of the electronic device, heat can flow from the plurality of height integrated circuits through the three-dimensional thermal joint to the heat sink, thereby lowering the temperature of the plurality of height integrated circuits. In such an exemplary embodiment, the plurality of height integrated circuits may include a 2D processor, a 2.5D processor, a 3D processor, a chiplet segmented processor, and the like.

[0042] Various aspects of the present invention as described herein include, but are not limited to, those listed in the following numbered sections. [Item 1] A method comprising using a thermal interface material to form a three-dimensional thermal joint that fills a plurality of gaps of varying distances between a first heat transfer surface and a second heat transfer surface of an electronic device, wherein the three-dimensional thermal joint formed by the thermal interface material is three-dimensionally shaped to have a plurality of different heights determined by the plurality of gaps filled by the thermal interface material between the first heat transfer surface and the second heat transfer surface of the electronic device, so that heat can flow through the three-dimensional thermal joint between the first heat transfer surface and the second heat transfer surface.

[0043] [Clause 2] The method according to Clause 1, wherein the thermal interface material comprises a rheology-controlled thermal interface material, and the method for forming the three-dimensional thermal joint between the first heat transfer surface and the second heat transfer surface of the electronic device comprises dispensing the rheology-controlled thermal interface material between the first heat transfer surface and the second heat transfer surface, and causing the rheology-controlled thermal interface material to fill a plurality of gaps of the various distances between the first heat transfer surface and the second heat transfer surface so as to form the three-dimensionally molded thermal joint having a plurality of different heights corresponding to the various distances, thereby providing an uninterrupted heat path between the first heat transfer surface and the second heat transfer surface.

[0044] [Clause 3] The method according to Clause 1, wherein the thermal interface material comprises a rheology-controlled thermal interface material and / or the thermal interface material comprises a metal amalgam containing non-refractory filler particles internally.

[0045] [Clause 4] The method according to Clause 3, wherein the non-fire-resistant filler particles include non-fire-resistant (not corrosion-resistant) metal filler particles. [Item 5] The non-refractory filler particles contain copper and nickel, and the metal amalgam contains about 1 percent to about 10 percent nickel and copper in a nickel:copper ratio of about 1:1 to about 5:1 in weight percent (wt%) and / or volume percent (vol%), or in a nickel:copper ratio of about 2:1 in weight percent (wt%) and / or volume percent (vol%), and / or the metal amalgam containing nickel and copper has a thermal conductivity of more than 15 W / mK and about 4 mm 2 Less than kW, but approximately 1 mm 2 The method according to item 3, having a thermal resistance of kW or more, and a viscosity of 2800 Pascal seconds or less at a shear rate of 0.5 / s and 75 Pascal seconds or less at a shear rate of 5 / s.

[0046] [Clause 6] The method according to Clause 1, wherein the thermal interface material comprises a gallium-based liquid metal containing copper particles and nickel particles. [Clause 7] The method according to Claim 6, wherein the gallium-based liquid metal comprises a low-viscosity gallium-indium-tin liquid metal alloy mixed with the copper particles and the nickel particles.

[0047] [Clause 8] The method according to Clause 1, wherein the thermal interface material comprises a rheology-controlled thermal interface material consisting solely of metal, the rheology-controlled thermal interface material does not contain any organic solvents or organic compounds that may reduce wettability and cause void formation from gas release during thermal cycling, and the rheology-controlled thermal interface material does not contain any silicone or polymer components that may reduce thermal conductivity.

[0048] [Clause 9] The method according to Clause 1, wherein the thermal interface material comprises a gallium-indium-tin liquid metal alloy containing copper and nickel, the gallium-indium-tin liquid metal alloy comprising a nickel:copper ratio in the range of about 1:1 to about 5:1 in weight percent (wt%) and / or volume percent (vol%).

[0049] [Clause 10] The method according to Clause 1, wherein the thermal interface material is a rheology-controlled thermal interface material comprising a metal amalgam, a liquid metal, or a low-melting-point alloy.

[0050] [Clause 11] The method according to Clause 1, wherein the thermal interface material comprises a low-melting-point alloy, the first heat transfer surface is defined by a first component of the electronic device, and the second heat transfer surface is defined by a second component of the electronic device, and the method comprises: assembling the first component to the second component such that the low-melting-point alloy is between the first heat transfer surface and the second heat transfer surface; heating the low-melting-point alloy to a temperature above the typical operating temperature of the electronic device to allow the low-melting-point alloy to flow into a plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface of the electronic device to fill the plurality of gaps of varying distances; and allowing the low-melting-point alloy to cool to form the three-dimensional thermal joint that fills the plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface of the electronic device.

[0051] [Clause 12] The method according to Clause 11, wherein assembling the first component to the second component includes applying pressure to the low-melting-point alloy between the first heat transfer surface and the second heat transfer surface, the pressure being removed or maintained during the operation of the electronic device.

[0052] [Clause 13] The method according to Clause 1, wherein the thermal interface material comprises a liquid metal, and the method comprises: applying the liquid metal to the first heat transfer surface and / or the second heat transfer surface; flowing the liquid metal into a plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface to fill the plurality of gaps of varying distances; and solidifying the liquid metal to form the three-dimensional thermal joint that fills the plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface of the electronic device.

[0053] [Clause 14] The method of Clause 13, wherein solidifying the liquid metal comprises solidifying the liquid metal at substantially room temperature, and therefore the liquid metal does not require heating to form the three-dimensional thermal joints that fill the plurality of gaps of various distances between the first heat transfer surface and the second heat transfer surface of the electronic device.

[0054] [Clause 15] The method according to Clause 1, wherein the thermal interface material comprises a metal alloy, and the method comprises: applying the metal alloy to the first heat transfer surface and / or the second heat transfer surface; heating the metal alloy to allow the molten metal alloy to flow into a plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface to fill the plurality of gaps of varying distances; and allowing the molten metal alloy to cool and re-solidify to form the three-dimensional thermal joint that fills the plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface of the electronic device.

[0055] [Clause 16] The method according to Clause 15, wherein the metal alloy comprises a gallium-based liquid metal alloy and / or has a melting point of about 160°C or less. [Clause 17] The method according to any one of Clauses 1 to 16, wherein the first heat transfer surface is defined by a heat removal / dissipation component, the second heat transfer surface is defined by a plurality of height heat sources, and the three-dimensional thermal joint formed of the thermal interface material is three-dimensionally molded to have a plurality of different heights determined by the plurality of gaps between the heat removal / dissipation component and the plurality of height heat sources that are filled by the thermal interface material, so that heat can flow from the plurality of height heat sources through the three-dimensional thermal joint to the heat removal / dissipation component during operation of the electronic device, thereby lowering the temperature of the plurality of height heat sources.

[0056] [Clause 18] The method according to any one of Clauses 1 to 16, wherein the first heat transfer surface is defined by a heat sink, the second heat transfer surface is defined by a plurality of height integrated circuits, and the three-dimensional thermal joint formed of the thermal interface material is three-dimensionally molded to have a plurality of different heights determined by a plurality of gaps between the heat sink and the plurality of height integrated circuits that are filled by the thermal interface material, so that heat can flow from the plurality of height integrated circuits through the three-dimensional thermal joint to the heat sink during operation of the electronic device, thereby lowering the temperature of the plurality of height integrated circuits.

[0057] [Clause 19] The method according to Clause 18, wherein the multiple height integrated circuits include a 2D processor, a 2.5D processor, a 3D processor, or a chiplet segmented processor. [Clause 20] The method according to any one of Clauses 1 to 10, wherein the first heat transfer surface is defined by a first component of the electronic device, and the second heat transfer surface is defined by a second component of the electronic device, and the method comprises applying the thermal interface material to the first heat transfer surface and / or the second heat transfer surface of the electronic device, and then assembling the first component to the second component; or assembling the first component to the second component, and then applying the rheology-controlled thermal interface material to fill a plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface of the electronic device.

[0058] [Clause 21] The method according to any one of Clauses 1 to 10, wherein the thermal interface material includes a preform, and the method comprises: placing the preform of the thermal interface material between a first heat transfer surface and a second heat transfer surface; heating the preform of the thermal interface material to allow the molten thermal interface material to flow into a plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface to fill the plurality of gaps of varying distances; and allowing the molten thermal interface material to cool and re-solidify to form a three-dimensional thermal joint that fills a plurality of gaps of varying distances between the first heat transfer surface and the second heat transfer surface of the electronic device.

[0059] [Clause 22] The method according to any one of Clauses 1 to 21, wherein the first heat transfer surface and / or the second heat transfer surface are defined by one or more of the following: a heat removal / dissipation structure, a heat source for an electronic device, a component of a solid-state drive, and / or a board-level shield.

[0060] [Clause 23] The method according to any one of Clauses 1 to 22, wherein the first heat transfer surface is defined by a heat removal / dissipation component such as a heat sink, heat spreader, heat pipe, vapor chamber, water block, device outer case, housing, or chassis, and the second heat transfer surface is defined by a heat source of an electronic device such as an integrated circuit or other components of an electronic device.

[0061] [Clause 24] The method according to any one of Clauses 1 to 23, wherein the thermal interface material exhibits isotropic diffusion control under compression between the surfaces such that movement, outflow, discharge, or escape during assembly and thermal cycling is restricted.

[0062] [Clause 25] The method according to any one of Clauses 1 to 24, wherein the thermal interface material provides a bond line thickness of approximately 3 μm to approximately 3 mm in situ.

[0063] [Clause 26] The thermal interface material having a thermal conductivity of at least 10 W / m·K, according to any one of Clauses 1 to 25. [Clause 27] The method according to any one of Clauses 1 to 26, wherein the thermal interface material is a liquid metal that forms the thermal joint at substantially room temperature without external heating.

[0064] [Clause 28] The method according to any one of Clauses 1 to 27, wherein the thermal interface material is a low-melting alloy that is heated to a melting point of about 160°C or less, dispensed or flowed to fill the plurality of gaps, and resolidified to form the three-dimensional thermal joint.

[0065] [Clause 29] The method according to any one of Clauses 1 to 28, wherein the thermal interface material forms the three-dimensional shape under gravity in a vertical orientation without self-leveling movement from the joint.

[0066] [Clause 30] The method according to any one of Clauses 1 to 29, wherein the three-dimensional thermal joint maintains its position during a thermal shock cycling test of at least 1,000 cycles in the range of -40°C to 150°C.

[0067] [Item 31] A three-dimensional thermal joint formed by the method described in any one of items 1 to 30. [Clause 32] The three-dimensional thermal joint according to Clause 31, wherein the first heat transfer surface is defined by a heat removal / dissipation component, the second heat transfer surface is defined by a plurality of height heat sources, and the three-dimensional thermal joint formed of the thermal interface material is three-dimensionally molded to have a plurality of different heights determined by a plurality of gaps between the heat removal / dissipation component and the plurality of height heat sources filled by the thermal interface material, so that heat can flow from the plurality of height heat sources through the three-dimensional thermal joint to the heat removal / dissipation component during operation of the electronic device, thereby lowering the temperature of the plurality of height heat sources.

[0068] [Clause 33] The three-dimensional thermal joint according to Clause 31, wherein the first heat transfer surface is defined by a heat sink, the second heat transfer surface is defined by a plurality of height integrated circuits, and the three-dimensional thermal joint formed of the thermal interface material is three-dimensionally molded to have a plurality of different heights determined by a plurality of gaps between the heat sink and the plurality of height integrated circuits that are filled by the thermal interface material, so that heat can flow from the plurality of height integrated circuits through the three-dimensional thermal joint to the heat sink during operation of the electronic device, thereby lowering the temperature of the plurality of height integrated circuits.

[0069] [Clause 34] The three-dimensional thermal joint according to Clause 33, wherein the multiple height integrated circuits include a 2D processor, a 2.5D processor, a 3D processor, or a chiplet segmented processor.

[0070] [Clause 35] An electronic device comprising a three-dimensional thermal joint formed by the method described in any one of Clauses 1 to 30. [Clause 36] The electronic device according to Clause 3, wherein the first heat transfer surface is defined by a heat removal / dissipation component, the second heat transfer surface is defined by a plurality of height heat sources, and the three-dimensional thermal joint formed of the thermal interface material is three-dimensionally molded to have a plurality of different heights determined by a plurality of gaps between the heat removal / dissipation component and the plurality of height heat sources that are filled by the thermal interface material, so that heat can flow from the plurality of height heat sources through the three-dimensional thermal joint to the heat removal / dissipation component during operation of the electronic device, thereby lowering the temperature of the plurality of height heat sources.

[0071] [Clause 37] The electronic device according to Clause 35, wherein the first heat transfer surface is defined by a heat sink, the second heat transfer surface is defined by a plurality of height integrated circuits, and the three-dimensional thermal joint formed of the thermal interface material is three-dimensionally molded to have a plurality of different heights determined by a plurality of gaps between the heat sink and the plurality of height integrated circuits that are filled by the thermal interface material, so that heat can flow from the plurality of height integrated circuits through the three-dimensional thermal joint to the heat sink during operation of the electronic device, thereby lowering the temperature of the plurality of height integrated circuits.

[0072] [Clause 38] The electronic device according to Clause 37, wherein the multiple height integrated circuits include a 2D processor, a 2.5D processor, a 3D processor, or a chiplet segmented processor.

[0073] [Clause 39] A three-dimensional thermal joint comprising a thermal interface material configured to fill a plurality of gaps of varying distances between a first heat transfer surface and a second heat transfer surface of an electronic device, wherein heat can flow through the three-dimensional thermal joint between the first heat transfer surface and the second heat transfer surface, and the three-dimensional thermal joint formed by the thermal interface material is three-dimensionally molded to have a plurality of different heights determined by the plurality of gaps between the first heat transfer surface and the second heat transfer surface of the electronic device that are filled by the thermal interface material.

[0074] [Clause 40] The three-dimensional thermal joint according to Clause 39, wherein the thermal interface material is a rheology-controlled thermal interface material comprising a metal amalgam, a liquid metal, or a low-melting-point alloy.

[0075] [Clause 41] The three-dimensional thermal joint according to Clause 39, wherein the thermal interface material comprises a rheology-controlled thermal interface material and / or the thermal interface material comprises a metal amalgam containing non-fire-resistant filler particles internally.

[0076] [Clause 42] The three-dimensional joint according to Clause 41, wherein the non-fire-resistant filler particles include non-fire-resistant (not corrosion-resistant) metal filler particles. [Item 43] The non-refractory filler particles contain copper and nickel, and the metal amalgam contains about 1 percent to about 10 percent nickel and copper in a nickel:copper ratio of about 1:1 to about 5:1 in weight percent (wt%) and / or volume percent (vol%), or in a nickel:copper ratio of about 2:1 in weight percent (wt%) and / or volume percent (vol%), and / or the metal amalgam containing nickel and copper has a thermal conductivity greater than 15 W / mK and about 4 mm 2 Less than kW, but approximately 1 mm 2A three-dimensional joint according to item 41 or 42, having a thermal resistance of kW or more, and a viscosity of 2800 Pascal seconds or less at a shear rate of 0.5 / s and 75 Pascal seconds or less at a shear rate of 5 / s.

[0077] [Clause 44] The three-dimensional joint according to any one of Clauses 39 to 43, wherein the thermal interface material comprises a gallium-based liquid metal containing copper particles and nickel particles. [Clause 45] The three-dimensional joint according to Clause 44, wherein the gallium-based liquid metal comprises a low-viscosity gallium-indium-tin liquid metal alloy mixed with copper particles and nickel particles.

[0078] [Clause 46] The three-dimensional joint according to any one of Clauses 39 to 45, wherein the thermal interface material comprises a rheology-controlled thermal interface material consisting solely of metal, the rheology-controlled thermal interface material does not contain any organic solvents or organic compounds that may reduce wettability and cause void formation from gas release during thermal cycling, and the rheology-controlled thermal interface material does not contain any silicone or polymer components that may reduce thermal conductivity.

[0079] [Clause 47] The three-dimensional joint according to any one of Clauses 39 to 46, wherein the thermal interface material comprises a gallium-indium-tin liquid metal alloy containing copper and nickel, the gallium-indium-tin liquid metal alloy comprising a nickel:copper ratio in the range of about 1:1 to about 5:1 in weight percent (wt%) and / or volume percent (vol%).

[0080] [Clause 48] The three-dimensional joint according to any one of Clauses 39 to 47, wherein the thermal interface material comprises a gallium-based liquid metal alloy and / or a metal alloy having a melting point of about 160°C or less.

[0081] [Clause 49] The three-dimensional thermal joint according to any one of Clauses 39 to 48, wherein the thermal interface material exhibits stable suspension and isotropic diffusion control of metal filler particles under assembly compression.

[0082] [Clause 50] The three-dimensional thermal joint according to any one of Clauses 39 to 49, wherein the three-dimensional thermal joint provides a bond line thickness of approximately 3 μm to approximately 3 mm and a thermal conductivity of at least 10 W / m·K in situ.

[0083] [Clause 51] The three-dimensional thermal joint according to any one of Clauses 39 to 50, wherein the maximum joint thickness that can be maintained without loss from the three-dimensional thermal joint is up to about 3 millimeters.

[0084] [Clause 52] An electronic device comprising a three-dimensional thermal joint as described in any one of Clauses 39 to 51. [Clause 53] The electronic device according to Clause 52, wherein the first heat transfer surface is defined by a heat removal / dissipation component, the second heat transfer surface is defined by a plurality of height heat sources, and the three-dimensional thermal joint formed of the thermal interface material is three-dimensionally molded to have a plurality of different heights determined by a plurality of gaps between the heat removal / dissipation component and the plurality of height heat sources that are filled by the thermal interface material, so that heat can flow from the plurality of height heat sources through the three-dimensional thermal joint to the heat removal / dissipation component during operation of the electronic device, thereby lowering the temperature of the plurality of height heat sources.

[0085] [Clause 54] The electronic device according to Clause 52, wherein the first heat transfer surface is defined by a heat sink, the second heat transfer surface is defined by a plurality of height integrated circuits, and the three-dimensional thermal joint formed of the thermal interface material is three-dimensionally shaped to have a plurality of different heights determined by a plurality of gaps between the heat sink and the plurality of height integrated circuits that are filled by the rheology-controlled thermal interface material, so that heat can flow from the plurality of height integrated circuits through the three-dimensional thermal joint to the heat sink during operation of the electronic device, thereby lowering the temperature of the plurality of height integrated circuits.

[0086] [Clause 55] The electronic device according to Clause 54, wherein the multiple height integrated circuits include a 2D processor, a 2.5D processor, a 3D processor, or a chiplet segmented processor.

[0087] [Item 56] A rheology-controlled metallic thermal interface material comprising a gallium-indium-tin liquid metal alloy mixed with copper and nickel particles, wherein the nickel:copper ratio is about 1:1 to about 5:1 by weight, and the total metal filler content is about 1 wt% to about 10 wt%, and the thermal interface material (a) a stable homogeneous suspension of the particles, (b) 0.5 s -1 and less than 2800 Pa·s and 5s -1 (c) Viscosity of 75 Pa·s or less, and thermal conductivity exceeding 15 W / m·K and 4 mm 2 A thermal interface material exhibiting a contact thermal resistance of less than kW.

[0088] [Clause 57] The thermal interface material according to Clause 56, wherein the nickel:copper ratio is approximately 2:1 by mass and the total filling amount is approximately 6 wt%. [Clause 58] The thermal interface material according to Clause 56 or 57, having a custard consistency with a filler addition of approximately 6 wt%, or having a spreadable paste consistency with a filler addition of approximately 8-10 wt%.

[0089] [Clause 59] A thermal interface material according to any one of Clauses 56 to 58, consisting solely of metal and free from organic solvents, organic compounds, silicones, and polymer components.

[0090] [Clause 60] The gallium alloy has a melting point of approximately 160°C or less, and is a thermal interface material according to any one of Clauses 56 to 59. The exemplary embodiments are provided to ensure that the disclosure is sufficient and fully conveys its scope to those skilled in the art. Numerous specific details are given, including examples of certain components, electronic devices, and methods, to provide a complete understanding of the embodiments of the disclosure. It will be apparent to those skilled in the art that the use of these specific details is not necessary, that the exemplary embodiments can be embodied in many different forms, and that neither should be construed as limiting the scope of the disclosure. In some exemplary embodiments, well-known processes, well-known electronic device structures, and well-known technologies are not described in detail. Furthermore, any advantages and improvements that may be achieved in one or more exemplary embodiments of the disclosure are provided for illustrative purposes only, and the exemplary embodiments of the disclosure do not limit the scope of the disclosure, as they may provide all or none of the above advantages and improvements and are still within the scope of the disclosure.

[0091] The specific dimensions, specific materials, and / or specific shapes disclosed herein are illustrative in nature and do not limit the scope of this disclosure. The disclosure herein regarding specific values ​​and ranges of values ​​for a given parameter does not preclude other values ​​and ranges of values ​​that may be useful in one or more examples disclosed herein. Furthermore, it is assumed that any two specific values ​​of a particular parameter described herein may define an endpoint of a range of values ​​that may be suitable for the given parameter (i.e., the disclosure of a first and second value of a given parameter may be interpreted as disclosing that any value between the first and second values ​​may be used for the particular parameter). For example, if parameter X is illustrated herein as having value A and also illustrated as having value Z, it is assumed that parameter X may have a range of values ​​from about A to about Z. Similarly, the disclosure of two or more ranges of values ​​for a parameter (whether such ranges are nested, overlapping, or distinct) is assumed to encompass all possible combinations of ranges of values ​​that may be claimed using the disclosed range endpoints. For example, if parameter X is exemplified herein as having values ​​in the range of 1 to 10, or 2 to 9, or 3 to 8, it is also conceivable that parameter X may have values ​​in other ranges, including 1 to 9, 1 to 8, 1 to 3, 1 to 2, 2 to 10, 2 to 8, 2 to 3, 3 to 10, and 3 to 9.

[0092] The terms used herein are for the sole purpose of describing specific exemplary embodiments and are not intended to be limiting. As used herein, the singular forms “one” and “it” are intended to include the plural form as well, unless the context clearly indicates otherwise. The terms “includes,” “contains,” and “have” are inclusive and thus identify the presence of the described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring their performance in a specific order described or illustrated unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be employed.

[0093] Where an element or layer is described as "on top of," "engaged with," "connected to," or "bonded to" another element or layer, it may be directly on top of, engaged with, connected to, or bonded to that other element or layer, or any intervening element or layer that may exist. In contrast, where an element is described as "directly on top of," "directly engaged with," "directly connected to," or "directly bonded to" another element or layer, there may be no intervening element or layer. Other words used to describe relationships between elements should be interpreted in a similar manner (e.g., "between" and "directly between," "adjacent" and "directly adjacent"). As used herein, the term "and / or" includes any and all combinations of one or more of the listed items relating to it.

[0094] When applied to a value, the term “approximately” indicates that the calculation or measurement allows for a slight inaccuracy in the value (approximately or reasonably close to the value, depending on the approach to accuracy of the value). Where, for any reason, the inaccuracy provided by “approximately” is not understood in this ordinary sense in the Art, “approximately” as used herein indicates at least the variation that may arise from the ordinary methods of measuring or using such a parameter. For example, the terms “generally,” “approximately,” and “substantially” may be used herein to mean within manufacturing tolerances. Alternatively, for example, when used when changing the amount of an ingredient or reactant of the Invention, for example, through careless errors in typical measurement and handling procedures used when producing concentrates or solutions in the real world; or through differences in the production, source, or purity of the ingredients used to make a composition or perform a method; the term “approximately” also encompasses different amounts due to different equilibrium conditions of compositions resulting from a particular initial mixture. Whether or not the term “approximately” is used, the claims include that quantity and an equivalent quantity.

[0095] Terms such as "first," "second," and "third" may be used herein to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms can only be used to distinguish one element, component, region, layer, or section from another region, layer, or section. As used herein, terms such as "first," "second," and other numerical terms do not imply order or sequence unless explicitly indicated by the context. Thus, a first element, component, region, layer, or section discussed below may be referred to as a second element, component, region, layer, or section without departing from the teaching of the exemplary embodiments.

[0096] Spatially relative terms such as “inside,” “outside,” “down,” “below,” “underside,” “up,” and “above” may be used herein to facilitate the description of the relationship between one element or feature and another, as shown in the figures. Spatially relative terms may be intended to encompass different orientations of an electronic device in use or operation, in addition to the orientation shown in the figures. For example, if the electronic device in the figure is turned upside down, an element described as “below” or “below” another element or feature becomes “above” the other element or feature. Thus, an example of the term “below” may encompass both up and down directions. The electronic device may be oriented differently (rotated 90 degrees or in other directions), and the spatially relative descriptors used herein may be interpreted accordingly.

[0097] The foregoing description of embodiments is provided for illustrative and explanatory purposes only. It is not intended to be exhaustive or to limit the disclosure. Individual elements, intended or described uses, or features of a particular embodiment are, in most cases, not limited to that particular embodiment, but are interchangeable where applicable and can be used in selected embodiments even if not specifically shown or described. The same can also be modified in many ways. Such modifications should not be considered deviations from the disclosure, and all such modifications are intended to be within the scope of the disclosure.

Claims

1. A method comprising using a thermal interface material to form a three-dimensional thermal joint that fills a plurality of gaps of varying distances between a first heat transfer surface and a second heat transfer surface of an electronic device, wherein the three-dimensional thermal joint formed by the thermal interface material is three-dimensionally shaped to have a plurality of different heights determined by the plurality of gaps filled by the thermal interface material between the first heat transfer surface and the second heat transfer surface of the electronic device, so that heat can flow through the three-dimensional thermal joint between the first heat transfer surface and the second heat transfer surface.

2. The thermal interface material includes a rheology-controlled thermal interface material. A method for forming the three-dimensional thermal joint between the first heat transfer surface and the second heat transfer surface of the electronic device is: Dispense the rheology-controlled thermal interface material between the first heat transfer surface and the second heat transfer surface, The rheology-controlled thermal interface material is made to fill the gaps of various distances between the first heat transfer surface and the second heat transfer surface in order to form the three-dimensionally molded thermal joint having a plurality of different heights corresponding to the various distances, The method according to claim 1, wherein the three-dimensional thermal joint provides an uninterrupted heat path between the first heat transfer surface and the second heat transfer surface.

3. The thermal interface material includes and / or a rheology-controlled thermal interface material. The method according to claim 1, wherein the thermal interface material comprises a metal amalgam containing non-fire-resistant filler particles internally.

4. The method according to claim 3, wherein the non-fire-resistant filler particles include non-fire-resistant (not corrosion-resistant) metal filler particles.

5. The non-fire-resistant filler particles contain copper and nickel. The aforementioned metal amalgam contains approximately 1 percent to approximately 10 percent nickel and copper. Nickel:copper ratio in the range of approximately 1:1 to approximately 5:1 in weight percent (wt%) and / or volume percent (vol%), or In weight percent (wt%) and / or volume percent (vol%), nickel:copper in a ratio of approximately 2:1 Mixed in, and / or The metal amalgam containing nickel and copper has a thermal conductivity of over 15 W / mK and a thickness of approximately 4 mm. ２ Less than kW, but approximately 1 mm ２ The method according to claim 3, having a thermal resistance of kW or more, and a viscosity of 2800 Pascal seconds or less at a shear rate of 0.5 / s and 75 Pascal seconds or less at a shear rate of 5 / s.

6. The method according to claim 1, wherein the thermal interface material comprises a gallium-based liquid metal containing copper particles and nickel particles.

7. The method according to claim 6, wherein the gallium-based liquid metal comprises a low-viscosity gallium-indium-tin liquid metal alloy mixed with copper particles and nickel particles.

8. The thermal interface material includes a rheology-controlled thermal interface material consisting solely of metal. The rheology-controlled thermal interface material does not contain any organic solvents or organic compounds that may reduce wettability and lead to void formation from gas release during thermal cycling. The method according to claim 1, wherein the rheology-controlled thermal interface material does not contain any silicone or polymer components that may reduce thermal conductivity.

9. The method according to claim 1, wherein the thermal interface material comprises a gallium-indium-tin liquid metal alloy containing copper and nickel, the gallium-indium-tin liquid metal alloy comprising a nickel:copper ratio in the range of about 1:1 to about 5:1 in weight percent (wt%) and / or volume percent (vol%).

10. The method according to claim 1, wherein the thermal interface material is a rheology-controlled thermal interface material comprising a metal amalgam, a liquid metal, or a low-melting-point alloy.

11. The thermal interface material includes a low-melting-point alloy. The first heat transfer surface is defined by the first component of the electronic device. The second heat transfer surface is defined by the second component of the electronic device. The aforementioned method, Assembling the first component to the second component such that the low-melting-point alloy is located between the first heat transfer surface and the second heat transfer surface; Heating the low-melting-point alloy to a temperature exceeding the typical operating temperature of the electronic device, thereby allowing the low-melting-point alloy to flow into the gaps of various distances between the first and second heat transfer surfaces of the electronic device, thereby filling the gaps of various distances; and, The method according to claim 1, comprising forming the three-dimensional thermal joint that fills a plurality of gaps of various distances between the first heat transfer surface and the second heat transfer surface of the electronic device by allowing the low-melting-point alloy to cool.

12. The method according to claim 11, wherein assembling the first component to the second component includes applying pressure to the low-melting-point alloy between the first heat transfer surface and the second heat transfer surface, the pressure being removable or maintained during operation of the electronic device.

13. The thermal interface material includes a liquid metal. The aforementioned method, Applying the liquid metal to the first heat transfer surface and / or the second heat transfer surface; The liquid metal is poured into the gaps of various distances between the first heat transfer surface and the second heat transfer surface to fill the gaps of various distances; and, The method according to claim 1, comprising solidifying the liquid metal to form the three-dimensional thermal joint that fills the plurality of gaps of various distances between the first heat transfer surface and the second heat transfer surface of the electronic device.

14. The method according to claim 13, wherein solidifying the liquid metal involves solidifying the liquid metal at substantially room temperature, and therefore the liquid metal does not require heating to form the three-dimensional thermal joint that fills the plurality of gaps of various distances between the first heat transfer surface and the second heat transfer surface of the electronic device.

15. The thermal interface material includes a metal alloy. The aforementioned method, Applying the aforementioned metal alloy to the first heat transfer surface and / or the second heat transfer surface; By heating the metal alloy, the molten metal alloy flows into the gaps of various distances between the first heat transfer surface and the second heat transfer surface, thereby filling the gaps of various distances; and, The method according to claim 1, comprising allowing the molten metal alloy to cool and re-solidify to form the three-dimensional thermal joint that fills the plurality of gaps of various distances between the first heat transfer surface and the second heat transfer surface of the electronic device.

16. The method according to claim 15, wherein the metal alloy includes a gallium-based liquid metal alloy and / or has a melting point of about 160°C or less.

17. The first heat transfer surface is defined by a heat sink. The second heat transfer surface is defined by an integrated circuit of multiple heights. The method according to any one of claims 1 to 16, wherein the three-dimensional thermal joint formed by the thermal interface material is three-dimensionally molded to have a plurality of different heights determined by the plurality of gaps between the heat sink and the plurality of height integrated circuits that are filled by the thermal interface material, so that heat can flow from the plurality of height integrated circuits through the three-dimensional thermal joint to the heat sink during operation of the electronic device, thereby lowering the temperature of the plurality of height integrated circuits.

18. A three-dimensional thermal joint comprising a thermal interface material configured to fill a plurality of gaps of varying distances between a first heat transfer surface and a second heat transfer surface of an electronic device, wherein heat can flow through the three-dimensional thermal joint between the first heat transfer surface and the second heat transfer surface, and the three-dimensional thermal joint formed by the thermal interface material is three-dimensionally molded to have a plurality of different heights determined by the plurality of gaps between the first heat transfer surface and the second heat transfer surface of the electronic device that are filled by the thermal interface material.

19. The three-dimensional thermal joint according to claim 18, wherein the thermal interface material is a rheology-controlled thermal interface material comprising a metal amalgam, a liquid metal, or a low-melting-point alloy.

20. The thermal interface material includes and / or a rheology-controlled thermal interface material. The three-dimensional thermal joint according to claim 18, wherein the thermal interface material comprises a metal amalgam containing non-fire-resistant filler particles internally.

21. The three-dimensional joint according to claim 20, wherein the non-fire-resistant filler particles include non-fire-resistant (not corrosion-resistant) metal filler particles.

22. The non-fire-resistant filler particles contain copper and nickel. The aforementioned metal amalgam contains approximately 1 percent to approximately 10 percent nickel and copper. Nickel:copper ratio in the range of approximately 1:1 to approximately 5:1 in weight percent (wt%) and / or volume percent (vol%), or In weight percent (wt%) and / or volume percent (vol%), nickel:copper in a ratio of approximately 2:1 It is mixed in, and / or The metal amalgam containing nickel and copper has a thermal conductivity of over 15 W / mK and a thickness of approximately 4 mm. ２ Less than kW, but approximately 1 mm ２ The three-dimensional joint according to claim 20, having a thermal resistance of kW or more, and a viscosity of 2800 Pascal seconds or less at a shear rate of 0.5 / s and 75 Pascal seconds or less at a shear rate of 5 / s.

23. The three-dimensional joint according to claim 18, wherein the thermal interface material comprises a gallium-based liquid metal containing copper particles and nickel particles.

24. The three-dimensional joint according to claim 23, wherein the gallium-based liquid metal comprises a low-viscosity gallium-indium-tin liquid metal alloy mixed with copper particles and nickel particles.

25. The thermal interface material includes a rheology-controlled thermal interface material consisting solely of metal. The rheology-controlled thermal interface material does not contain any organic solvents or organic compounds that may reduce wettability and lead to void formation from gas release during thermal cycling. The three-dimensional joint according to claim 18, wherein the rheology-controlled thermal interface material does not contain any silicone or polymer components that may reduce thermal conductivity.

26. The three-dimensional joint according to claim 18, wherein the thermal interface material comprises a gallium-indium-tin liquid metal alloy containing copper and nickel, the gallium-indium-tin liquid metal alloy comprising a nickel:copper ratio in the range of about 1:1 to about 5:1 in weight percent (wt%) and / or volume percent (vol%).

27. The three-dimensional joint according to claim 18, wherein the thermal interface material includes a gallium-based liquid metal alloy and / or a metal alloy having a melting point of about 160°C or less.

28. An electronic device comprising a three-dimensional thermal joint according to any one of claims 18 to 27, The first heat transfer surface is defined by a heat sink. The second heat transfer surface is defined by an integrated circuit of multiple heights. The three-dimensional thermal joint formed by the thermal interface material is three-dimensionally shaped to have a plurality of different heights, determined by a plurality of gaps between the heat sink and the plurality of height integrated circuits filled by the rheology-controlled thermal interface material, so that heat can flow from the plurality of height integrated circuits through the three-dimensional thermal joint to the heat sink during operation of the electronic device, thereby lowering the temperature of the plurality of height integrated circuits.