Thermal interface materials containing functionalized liquid metal droplets, formed circuit assemblies, and methods for manufacturing them.

Abstract

A thermal interface material comprising a functionalized liquid metal droplet, a circuit assembly formed therefrom, and a method for manufacturing them are provided. The thermal interface material comprises a polymer component and liquid metal droplets dispersed throughout the polymer component. At least a portion of the liquid metal droplet includes an outer surface containing a metal oxide. The thermal interface material comprises a functionalized component bonded to at least a portion of the metal oxide by an acid.

Description

Technical Field

[0001] <Cross - Reference to Related Applications> This application claims priority to U.S. Provisional Patent Application No. 63 / 489,XX, filed on March 8, 2023, the content of which is incorporated herein by reference.

[0002] This disclosure relates to a thermal interface material comprising functionalized liquid metal droplets, a circuit assembly formed therefrom, and methods of manufacturing them.

Background Art

[0003] Thermal interface materials (TIMs) can be used to thermally connect two or more layers together. For example, TIMs are often used in a CPU package to thermally connect the integrated heat spreader (IHS) of the CPU package to a heat sink. There are various types of TIMs that can be used. However, current TIMs present challenges.

Summary of the Invention

[0004] In one general aspect, this disclosure is directed to a thermal interface material comprising a polymer component and liquid metal droplets dispersed throughout the polymer component. The liquid metal droplets have a melting point of 30 degrees Celsius or less, a D within the range of 1 micron to 300 microns, and / or can include at least one of gallium, gallium alloys, indium, indium alloys, tin, tin alloys, mercury, and mercury alloys. At least a portion of the liquid metal droplets includes an outer surface comprising at least one of metal oxides such as gallium oxide, indium oxide, tin oxide, iron oxide, and mercury oxide. The thermal interface material includes a functionalized component (e.g., a coupling agent, a polymer chain) bonded to at least a portion of the metal oxide by an acid, such as at least one of sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, and carboxylic acid. In various examples, the concentration of the functionalized component on the surface of the liquid metal droplets is 1×10 90 ~5 units / nm -6 ~5 units / nm It should be noted that in the original text, the numbers in ' ' etc. and the number in '1×10 ' are not complete in the provided text. The translation is based on the existing text content as accurately as possible. If there are any errors or missing information in the original text, it may affect the understanding and integrity of the translation.2 It is within the range. In various examples, the thermal interface material includes additional components, such as at least one of catalysts, rigid particles, coupling agents, and fumed silica.

[0005] In another general embodiment, the present disclosure covers an assembly comprising a first layer, a second layer, and a thermal interface material according to the present disclosure disposed in contact with and between the first and second layers.

[0006] In another general embodiment, the Disclosure relates to a method comprising applying the thermal interface material according to the Disclosure onto a first layer of an assembly such that the thermal interface material is in contact with and between a first layer and a second layer of the assembly. The method comprises compressing the assembly and thereby deforming the liquid metal droplets. D of the liquid metal droplets in the thermal interface material before application 90 This is greater than the thickness of the bond line formed between the first and second layers.

[0007] In another general embodiment, the disclosure relates to a method for producing a thermal interface material. This method includes combining a polymer component and a liquid metal to form an intermediate mixture. This method includes dispersing the liquid metal throughout the polymer component in the intermediate mixture to form liquid metal droplets having an outer surface containing a metal oxide. This method includes contacting the metal oxide with an acid to form a functionalized component bonded to at least a portion of the metal oxide.

[0008] The present invention can provide both low contact resistance at the material interface and low thermal resistance through the TIM. Low contact resistance can be achieved by applying a polymer in a conformable state so that the polymer and liquid metal droplets can conform to the surface of the layer and achieve the desired contact resistance. Low thermal resistance through the TIM can be achieved by the liquid metal droplets, including the size and / or shape of the liquid metal droplets. In addition, the methods described herein can achieve the desired uniformity of the liquid metal droplets in the TIM, the desired distribution of the liquid metal droplets on the circuit assembly, and / or the desired shape of the liquid metal droplets in the TIM, thereby improving the effective thermal conductivity of the TIM. These and other advantages achievable from various embodiments of the present invention will be apparent from the following description. [Brief explanation of the drawing]

[0009] The features and advantages of various embodiments of the present invention, as well as the ways in which they are achieved, will become clearer, and the embodiments will be better understood by referring to the following description of the embodiments illustrated in conjunction with the accompanying drawings.

[0010] [Figure 1] This is a perspective view of the assembly according to this disclosure after deposition of the thermal interface material.

[0011] [Figure 2] This is a side view of the assembly formed by compressing the first and second layers of Figure 1.

[0012] Corresponding reference letters indicate corresponding parts across several figures. The examples described herein illustrate a particular embodiment in one form, and such examples should not be construed as limiting the scope of the embodiment in any way. [Modes for carrying out the invention]

[0013] Certain exemplary embodiments of the present invention are described herein to provide an overall understanding of the principles and methods of the compositions, functions, manufactures, and uses of the compositions disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the compositions, articles, and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments, and that the scope of the various embodiments of the present invention is defined solely by the claims. Features illustrated or described in relation to one exemplary embodiment may be combined with features of other embodiments. Such modifications and variations are intended to fall within the scope of the present invention.

[0014] Appropriate formulation of a thermal interface material (TIM) applied to a circuit assembly between an integrated heat spreader (IHS) and a heat sink may require balancing the thermal resistance through the TIM with the contact resistance at the material interface. For example, polymer materials may have low contact resistance at the material interface but high thermal resistance through the material. Solid metals may have low thermal resistance through the material but high contact resistance at the material interface. In addition, some solid materials (polymers or metals) may require high pressure during installation to achieve the desired contact resistance. Furthermore, when using a TIM with liquid metal droplets, the inventors have found challenges in achieving the desired distribution of liquid metal droplets on the circuit assembly, the desired stability of the liquid metal droplets and polymer component emulsion in the TIM, the desired shape of the liquid metal droplets on the circuit assembly, and the uniformity of the liquid metal in the TIM, and these challenges may affect the effective thermal conductivity through the TIM.

[0015] Therefore, the inventors provide a thermal interface material comprising, in various examples, a polymer component and liquid metal droplets dispersed throughout the polymer component. At least a portion of the liquid metal droplets includes an outer surface containing a metal oxide. The thermal interface material includes a functionalizing component bonded to at least a portion of the metal oxide by an acid. The thermal interface material according to this disclosure can improve the resistance of the liquid metal droplets to migration through the polymer component, improve the affinity of the liquid metal droplets to the polymer component, enable the liquid metal droplets to be crosslinked to the polymer component, and / or improve the surface wettability of the liquid metal droplets. Therefore, the thermal interface material according to this disclosure can achieve a desired distribution of liquid metal droplets on a circuit assembly, a desired stability of the liquid metal droplet and polymer component emulsion in the TIM, a desired shape of the liquid metal droplets on the circuit assembly, uniformity of the liquid metal in the TIM, and / or improved effective thermal conductivity.

[0016] As used herein, the terms “on,” “onto,” and “over,” and their variations (e.g., “applied on,” “formed on,” “deposited on,” “provided on,” “located on,” etc.), particularly in relation to layers, films, or materials, mean that they are applied to, formed on, deposited on, provided on, or otherwise located on the surface of a substrate, but not necessarily in contact with the surface of the substrate. For example, a TIM “deposited on” a substrate or “deposited between” two elements does not preclude the presence of another layer or other layer of the same or different composition located between the applied TIM and the substrate or layer. Similarly, a second layer “deposited on” a first layer does not preclude the presence of another layer or other layer of the same or different composition located between the deposited second layer and the deposited TIM.

[0017] As used herein, the terms “polymer” and “polymeric” mean both prepolymers, oligomers, and homopolymers and copolymers. As used herein, “prepolymer” means a polymer precursor that can undergo further reaction or polymerization with one or more reactive groups to form a higher molecular weight or crosslinked state.

[0018] The polymer may be at least one of a polymer binder, a thermosetting polymer, and a thermoplastic polymer. As used herein, the term “thermosetting” refers to a polymer that “cures” irreversibly upon curing or crosslinking, where the polymer chains of the polymer component are covalently bonded together, and these covalent bonds are often induced, for example, by heat or radiation. In various examples, the curing or crosslinking reaction may be carried out under ambient conditions. Once cured or crosslinked, a thermosetting polymer may become non-flowing upon application of heat, irreversibly increase in viscosity, and / or be insoluble in conventional solvents. As used herein, the term “thermoplastic” refers to a polymer containing a polymer component whose constituent polymer chains are not covalently bonded (e.g., crosslinked), thereby allowing it to undergo liquid flow upon heating and being soluble in conventional solvents. In certain embodiments, the polymer may be an elastomer (e.g., rubbery, soft, stretchable) or a rigid (e.g., glassy). For example, the polymer may be an elastomer.

[0019] The thermosetting polymer may contain at least one crosslinking agent, which may include, for example, aminoplasts, polyisocyanates (including blocked isocyanates), polyepoxides, beta-hydroxyalkylamides, polyacids, anhydrides, organometallic acid functional materials, polyamines, polyvinyl, hydrogenated polysilicon, polyalcohols, polyacid chlorides, polyhalides, and polyamides. The polymer may have functional groups that react with the crosslinking agent.

[0020] The thermosetting polymers in TIM described herein may be selected from any of the various polymers known in the art. For example, the thermosetting polymers may include acrylic polymers, acrylate polymers, vinyl polymers, polyester polymers, polyurethane polymers, polybutadiene, polyamide polymers, polyether polymers, polysiloxane polymers (e.g., poly(dimethylsiloxone)), silicon hydrogenation polymers, fluoropolymers, polyisoprene polymers (e.g., rubber), and at least one copolymer of two or more of these. The functional groups on the thermosetting polymers may be selected from any of the various reactive functional groups, including at least one of carboxylic acid groups, amine groups, epoxide groups, hydroxyl groups, thiol groups, carbamate groups, amide groups, urea groups, isocyanate groups (including blocked isocyanate groups), vinyl groups, silicon hydrogenation groups, acid chloride groups, acrylate groups, halide groups, and mercaptan groups.

[0021] The thermoplastic polymer may include at least one of propylene-ethylene copolymer, styrene-butadiene-styrene, and styreneethylenebutylenestyrene. The polymer may have a melting point of at least 100 degrees Celsius, for example, at least 120 degrees Celsius, at least 150 degrees Celsius, or at least 200 degrees Celsius.

[0022] The polymer binder may be a polyether binder.

[0023] Liquid metal droplets for TIM may include at least one of gallium, gallium alloys, indium, indium alloys, tin, tin alloys, mercury, and mercury alloys. Liquid metal droplets may have melting points of 30 degrees Celsius or less, for example, 25 degrees Celsius or less, 20 degrees Celsius or less, 15 degrees Celsius or less, 10 degrees Celsius or less, 5 degrees Celsius or less, 0 degrees Celsius or less, or -10 degrees Celsius or less. Liquid metal droplets may have melting points of at least -40 degrees Celsius, for example, at least -20 degrees Celsius, at least -19 degrees Celsius, at least -10 degrees Celsius, at least 0 degrees Celsius, at least 5 degrees Celsius, at least 10 degrees Celsius, at least 15 degrees Celsius, at least 20 degrees Celsius, or at least 25 degrees Celsius. Liquid metal droplets can have melting points within a range of -40°C to 30°C, for example, -20°C to 30°C, -19°C to 30°C, or -19°C to 25°C. The melting point can be determined at a pressure of 1 absolute atmosphere. In certain embodiments, the TIM can include gallium indium tin (Galinstan) with a melting point of -19°C.

[0024] At least a portion of the liquid metal droplet includes an outer surface containing a metal oxide. For example, at least 5% of the surface area of ​​the outer surface can be covered with a metal oxide film, and for example, at least 10%, at least 20%, at least 30%, at least 40%, at least 60%, at least 70%, or at least 80% of the surface area of ​​the outer surface can be covered with a metal oxide film.

[0025] The metal oxide may include transition metal oxides. The metal oxide may include at least one of gallium oxide, indium oxide, tin oxide, iron oxide, mercury oxide, aluminum oxide, nickel oxide, zinc oxide, copper oxide, and other metal oxides. For example, in cases where the liquid metal droplet contains gallium or a gallium alloy, a film of gallium oxide may form on the liquid metal droplet by oxidation due to exposure to water and / or air. In various examples, the metal oxide film may be formed by the incorporation of metal oxide particles (e.g., aluminum oxide, zinc oxide) into the polymer binder or into the liquid metal droplet.

[0026] The functionalizing component can be bonded to at least a portion of the metal oxide by an acid. For example, the functionalizing component can be bonded to at least a portion of the metal oxide (e.g., covalent bond, ionic bond). The functionalizing component may include coupling agents, polymer chains, or combinations thereof. The polymer chains may have molecular weights of at least 400 g / mol when measured by gel permeation chromatography (GPC), for example, at least 500 g / mol, at least 1,000 g / mol, at least 2,000 g / mol, or at least 5,000 g / mol when all measured by GPC. In various examples, the polymer chains may include at least one of acrylic polymers, acrylate polymers, vinyl polymers, polyester polymers, polyurethane polymers, polybutadiene polymers, polyamide polymers, polyether polymers, polysiloxane polymers, hydrogenated silicon polymers, fluoropolymers, polyisoprene polymers, polystyrene polymers, polyepoxide polymers, and any two or more copolymers thereof. In certain examples, the functionalizing component includes an acid-functionalized polymer.

[0027] The acid may be Brønsted-Lowry acid. The acid may include at least one of the following: an acid containing a sulfate group, an acid containing a nitrate group, an acid containing a phosphoric acid group, an acid containing a chloride group, an acid containing a bromide group, an acid containing an iodide group, a carboxylic acid, and an acid containing a sulfonic acid group. For example, the acid may include at least one of sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, and a carboxylic acid. The acid may be a monobasic acid or a polybasic acid.

[0028] The amount of functionalizing components bonded to at least a portion of the metal oxide may be sufficient to achieve improved resistance of the liquid metal droplets to moving through the polymer component by at least one of steric hindrance and charge repulsion, compared to liquid metal droplets not bonded to the functionalizing components; improved affinity of the liquid metal droplets to the polymer component, compared to liquid metal droplets not bonded to the functionalizing components; enable crosslinking of the liquid metal droplets to the polymer component; and / or improved surface wettability of the liquid metal droplets compared to liquid metal droplets not bonded to the functionalizing components.

[0029] The surface wettability of a liquid metal droplet can be determined by measuring the contact angle of the liquid metal droplet. Liquid metal droplets according to this disclosure may have a contact angle of 120 degrees or less, for example, 100 degrees or less or 75 degrees or less. Liquid metal droplets according to this disclosure may have a contact angle of at least 30 degrees, for example, at least 40 degrees. In various examples, liquid metal droplets according to this disclosure may have a contact angle in the range of 30 degrees to 120 degrees, for example, 30 degrees to 100 degrees. Some conventional liquid metal droplets without functionalizing components may have a contact angle greater than 150 degrees. The reduced contact angle of liquid metal droplets according to this disclosure may be a result of reduced surface energy on the liquid metal droplet, which correlates with the surface density of the functionalizing component. For example, the concentration of the functionalizing component on the surface of the liquid metal droplet is 1 × 10⁻⁶ on the outer surface of the liquid metal droplet. -6 ~5 molecules / nm 2It may be within a certain range. The contact angle can be measured by placing a liquid metal droplet on a glass slide and using an optical microscope to measure the angle formed by the droplet at the point where the liquid-vapor interface of the droplet contacts the glass slide.

[0030] Adding functionalizing components that increase the size of liquid metal droplets can induce improved steric hindrance, which can suppress the movement of liquid metal droplets within the polymer component. Adding functionalizing components with a similar charge to the polymer component can also suppress the movement of liquid metal droplets within the polymer component due to charge repulsion.

[0031] Adding a functionalizing component to a liquid metal droplet with a similar composition to the polymer matrix and / or a charge opposite to that of the polymer component (e.g., charge attraction) can improve the affinity of the liquid metal droplet to the polymer component compared to a liquid metal droplet that is not bound to the functionalizing component.

[0032] In various examples, functionalizing components can be configured to crosslink with polymer components. For instance, functionalizing components can participate in polymerization reactions with polymer components and chemically bond to them.

[0033] In various examples, the metal oxide includes gallium oxide, the liquid metal droplets include gallium or gallium alloys, the acid is a carboxylic acid, and the functionalizing component includes polymer chains covalently bonded to the carboxylic acid.

[0034] TIM can be produced by combining polymer components and liquid metal to form an intermediate mixture. This method may further include dispersing the liquid metal throughout the polymer components in the intermediate mixture, thereby forming liquid metal droplets having an outer surface containing metal oxides. For example, the polymer and bulk liquid metal can be mixed together to form an emulsion by at least one of the following: a high-shear mixer, a centrifugal mixer, shaking in a container, a mortar and pestle, and ultrasonic treatment.For more details on exemplary methods for forming polymer emulsions and liquid metal droplets, see (1) published PCT WO / 2019 / 136252, “Method of Synthesizing a Thermally Conductive and Stretchable Polymer Composite”, (2) published U.S. application No. 2017 / 0218167, “Polymer Composite with Liquid Phase Metal Inclusions”, (3) U.S. Patent No. 10,777,483, “Method, apparatus, and assembly for thermally connecting layers”, (4) provisional U.S. patent No. 63 / 268,134, “Thermal interface material, an integrated circuit assembly, and a method for thermally connecting layers”, (5) published PCT WO 2022 / 204689, “A method of This is described in U.S. Provisional Application No. 63 / 479,879, titled "Manufacture of a Thermal Interface Material, a Thermal Interface Material Formed Therefrom, and an Integrated Circuit Formed Therefrom," all of which are incorporated herein by reference.

[0035] A method for producing TIM may include contacting a metal oxide with an acid to form a functionalized component bonded to at least a portion of the metal oxide. For example, an acid and / or acid-functionalized polymer can be reacted with a metal oxide after the liquid metal has been dispersed throughout the polymer component and / or before the polymer component and the liquid metal are combined. In certain examples, the functionalized component can be added to the emulsion after the liquid metal has been dispersed throughout the polymer. In various examples, the functionalized component can be added to the polymer component before the polymer component is combined with the liquid metal. In certain examples, the functionalized component can be added to the liquid metal before the polymer component is combined with the liquid metal.

[0036] The composition and / or mixing technique can be selected such that the viscosity of the TIM is less than 850,000 cP (centipoise), for example less than 750,000 cP, less than 500,000 cP, less than 250,000 cP, 200,000 cP, less than 150,000 cP, less than 100,000 cP, less than 50,000 cP, less than 15,000 cP, less than 14,000 cP, less than 13,000 cP, less than 12,000 cP, less than 11,000 cP, or less than 10,000 cP. For example, the composition and / or mixing technique can be selected such that the viscosity of the TIM is at least 1,000 cP, for example at least 2,000 cP, at least 5,000 cP, or at least 10,000 cP. The composition and / or mixing technique can be selected so that the viscosity of the TIM is within the range of 1,000 cP to 850,000 cP, for example, 2,000 cP to 750,000 cP, or 2,000 cP to 500,000 cP. The viscosity of the TIM emulsion can be measured by a parallel plate (40 mm) rheometer at 25 degrees Celsius, a frequency of 10 radians per second, and a strain of 5%. Selecting the viscosity may require a balance between the increased installation pressure that can result from higher viscosity and the ability to resist undesirable rapid spreading during TIM application and pump-out during operation.

[0037] The TIM can include liquid metal droplets that are at least 1% of the total volume of the TIM, based on the total volume of all liquid metal droplets, for example, at least 5% of the liquid metal droplets, at least 10% of the liquid metal droplets, at least 20% of the liquid metal droplets, at least 30% of the liquid metal droplets, at least 40% of the liquid metal droplets, at least 50% of the liquid metal droplets, at least 60% of the liquid metal droplets, at least 70% of the liquid metal droplets, at least 80% of the liquid metal droplets, or at least 90% of the liquid metal droplets, etc. The TIM can include liquid metal droplets that are 95% or less of the total volume of the TIM, based on the total volume of all the TIM, for example, 93% or less of the liquid metal droplets, 90% or less of the liquid metal droplets, 80% or less of the liquid metal droplets, 70% or less of the liquid metal droplets, 60% or less of the liquid metal droplets, 50% or less of the liquid metal droplets, 40% or less of the liquid metal droplets, 30% or less of the liquid metal droplets, 20% or less of the liquid metal droplets, or 10% or less of the liquid metal droplets, etc. The TIM can include a range of liquid metal droplets that are 1% - 95% of the total volume of the TIM, based on the total volume of all the TIM, for example, 5% - 93% of the liquid metal droplets, 50% - 93% of the liquid metal droplets, 60% - 93% of the liquid metal droplets, 70% - 95% of the liquid metal droplets, or 70% - 93% of the liquid metal droplets, etc. The amount of liquid metal droplets can be selected while balancing the desired elasticity and the desired effective thermal conductivity of the TIM.

[0038] The composition and / or mixing technique can be selected to achieve the desired D of the liquid metal droplets in the TIM before compression 50 and / or D 90 The D of the liquid metal droplets 50 can be, before compression, at least 1 micron, all before compression, for example, at least 5 microns, at least 10 microns, at least 15 microns, at least 20 microns, at least 30 microns, at least 35 microns, at least 40 microns, at least 50 microns, at least 60 microns, at least 70 microns, at least 80 microns, at least 90 microns, at least 100 microns, at least 120 microns, at least 150 microns, or at least 200 microns, etc. The D of the liquid metal droplets 50These are all 300 microns or less before compression, and may be, for example, 250 microns or less, 200 microns or less, 150 microns or less, 120 microns or less, 100 microns or less, 90 microns or less, 80 microns or less, 70 microns or less, 60 microns or less, 50 microns or less, 40 microns or less, 35 microns or less, 30 microns or less, 20 microns or less, 10 microns or less, or 5 microns or less. For example, D of a liquid metal droplet. 50 The micron size can range from 1 micron to 300 microns, all measured before compression, and may fall within ranges such as 5 microns to 300 microns, 150 microns to 250 microns, 5 to 150 microns, 15 to 150 microns, 35 microns to 150 microns, 35 microns to 70 microns, or 5 microns to 100 microns.

[0039] When used in this specification, D x The size can be measured using microscopy (e.g., optical microscopy or electron microscopy). The size may be the diameter of a spherical particle, or, in the case of an ellipsoidal or other irregularly shaped particle, the length along the maximum dimension. When used herein, the "D" of a particle refers to the diameter of a spherical particle. X " represents the diameter at which X% of the particle's volume has a smaller diameter.

[0040] D of liquid metal droplets 90 The diameter of the liquid metal droplet is at least 1 micron, all before compression, and can be, for example, at least 5 microns, at least 10 microns, at least 15 microns, at least 20 microns, at least 30 microns, at least 35 microns, at least 40 microns, at least 50 microns, at least 60 microns, at least 70 microns, at least 80 microns, at least 90 microns, at least 100 microns, at least 120 microns, at least 150 microns, or at least 200 microns. 90The size can be 300 microns or less, all before compression, for example, 250 microns or less, 200 microns or less, 150 microns or less, 120 microns or less, 100 microns or less, 90 microns or less, 80 microns or less, 70 microns or less, or 50 microns or less. For example, D of a liquid metal droplet. 90 The micron size can range from 1 micron to 300 microns, all measured before compression, and may fall within ranges such as 5 microns to 300 microns, 150 microns to 250 microns, 10 to 200 microns, 15 microns to 150 microns, 35 microns to 150 microns, 35 microns to 120 microns, or 50 microns to 100 microns.

[0041] TIM may optionally include other components, such as rigid particles, catalysts, fumed silica, and coupling agents. The rigid particles may include at least one of iron, iron alloys (e.g., steel), vanadium, vanadium alloys, niobium, niobium alloys, titanium, titanium alloys, copper, copper alloys (e.g., bronze), rigid polymers, glass, and ceramics. The rigid particles may be resistant to deformation and / or corrosion by liquid metal droplets. For example, the rigid particles may have a Young's modulus of at least 100 MPa (megapascals), e.g., at least 110 MPa, at least 150 MPa, at least 200 MPa, at least 250 MPa, at least 500 MPa, at least 750 MPa, at least 1 GPa (gigapascals), or at least 2 GPa. The Young's modulus can be measured according to ASTM E111-17. TIM can include a range of rigid particles, such as 0.1% to 30% of the total volume of TIM, 0.1% to 10% of rigid particles, 0.1% to 5% of rigid particles, 1% to 10% of rigid particles, or 1% to 5% of rigid particles, based on the total volume of TIM.

[0042] In various examples, the polymer component may contain 0.1% to 0.5% by weight of a coupling agent, based on the total weight of the polymer component. For example, the coupling agent may include at least one of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and bis(3-trimethoxysilylpropyl)amine.

[0043] In various examples, the polymer component may contain 0.1% to 0.5% by weight of a coupling agent, based on the total weight of the polymer component. For example, the coupling agent may include at least one of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and bis(3-trimethoxysilylpropyl)amine.

[0044] In certain examples, the polymer component may contain 0.1% to 5% by weight of fumed silica, based on the total weight of the polymer component.

[0045] D of rigid particles in TIM 50 The rigid particles may be selected to achieve a desired bond line thickness in the assembly. The average particle size of the rigid particles may be at least 1 micron, for example, at least 5 microns, at least 10 microns, at least 20 microns, at least 30 microns, at least 35 microns, at least 40 microns, at least 50 microns, at least 60 microns, at least 70 microns, at least 80 microns, at least 90 microns, at least 100 microns, at least 120 microns, or at least 125 microns. 50 This can be 150 microns or less, for example, 125 microns or less, 120 microns or less, 100 microns or less, 90 microns or less, 80 microns or less, 70 microns or less, 60 microns or less, 50 microns or less, 40 microns or less, 35 microns or less, 30 microns or less, 20 microns or less, 10 microns or less, or 5 microns or less. For example, the D of rigid particles 50This can be within the range of 1 to 150 microns, for example, 15 to 150 microns, 5 to 125 microns, 35 to 125 microns, 35 to 70 microns, or 50 to 70 microns.

[0046] TIM can be applied to various layers and devices, and is described below with reference to circuit assemblies and Figures 1-2, but is not limited to circuit assemblies and can be applied to other assemblies. Referring to Figure 1, the method according to the present disclosure includes depositing TIM 104 according to the present disclosure between a first layer 106 and a second layer 108 of assembly 102. The thickness of the TIM can be selected based on the desired application.

[0047] Deposition of TIM104 can include, for example, dispensing, extrusion (through a nozzle such as a circular nozzle, fan nozzle, or other nozzle shape), application with an instrument (e.g., brush, spatula), stencil printing, 3D printing, and screen printing. TIM104 can be deposited in a conformable state so that it conforms to the surfaces of the first layer 106 and the second layer 108 to achieve a desired level of surface contact between them. In various examples, TIM104 can be applied directly to the first layer 106, and then the second layer 108 can be applied directly to TIM104. In various other examples, TIM104 can be applied directly to the second layer 108, and then the first layer 106 can be applied directly to TIM104. In certain examples, TIM104 can be applied to both the first layer 106 and the second layer 108, and then the first layer 106 and the second layer 108 can be applied together. In various examples, after the deposition of TIM 104 and the compression of assembly 102, TIM 104 may come into direct contact with the first layer 106 and the second layer 108. In certain examples, the application of TIM 104 may be limited to the surface of the first layer 106 so that TIM 104 can be used efficiently.

[0048] TIM104 can be dispensed from a container and applied to a layer in a conformable state. TIM104 can be stored in the container before use. TIM104 may be in a conformable state within the container. The container may include at least one of a pillow pack, syringe, beaker, bottle, and drum. In various examples, the container may be a readily available dispensing device, such as a pillow pack or syringe. In certain examples, TIM104 may not be stored and can be used after emulsion preparation without storage.

[0049] TIM104 can be applied to at least 1% of the surface area of ​​the exposed side 106a of the first layer 106, or to all of the surface area of ​​the exposed side 106a of the first layer 106, for example, at least 2%, at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, or at least 50%, etc., before the assembly 102 is compressed. For example, TIM104 can be applied to 1% to 100% of the surface area of ​​the exposed side 106a of the first layer 106, or to all of the surface area of ​​the exposed side 106a of the first layer 106, for example, 2% to 100%, 5% to 90%, or 5% to 80%, etc., before the assembly 102 is compressed.

[0050] The first layer 106 is a heat-generating electronic component (e.g., battery, memory, data storage unit, power inverter, thermoelectric generator, motor winding, integrated circuit) and / or can be thermally connected to the heat-generating electronic component. The integrated circuit may comprise a processor (e.g., central processing unit (CPU), tensor processing unit (TPU), graphics processing unit (GPU), processor specialized for artificial intelligence, ASIC, and / or system-on-a-chip (SOC)). The second layer 108 may be a top layer that can be thermally conductive. The first layer 106 and the second layer 108 may, individually, comprise at least one of a battery, processor, heat sink (e.g., fin, fan, liquid cooling, cooling plate, heat sink, heat wick, heat pipe), integrated heat spreader, and packaging. In various examples, the first layer 106 may comprise a processor, and the second layer 108 may comprise at least one of a heat sink, integrated heat spreader, and packaging. In certain examples, the first layer 106 may include an integrated heat spreader, and the second layer 108 may include at least one of a heat sink, an integrated heat spreader, and packaging. In various examples, the first layer 106 may include a battery, and the second layer 108 may include at least one of a heat sink, an integrated heat spreader, and packaging.

[0051] After the deposition of TIM104, this method includes compressing the assembly 102, thereby deforming the liquid metal droplets 112 and forming the assembly 202. For example, referring to the detailed diagrams in Figures 1-2, the first layer 106 and the second layer 108 can both be biased. For example, compressing the assembly 102 may include applying a pressure to the first layer 106 and the second layer 108 of at least 1 psi, for example, at least 5 psi, at least 10 psi, at least 15 psi, or at least 20 psi. Compressing the assembly 102 may include applying a pressure to the first layer 106 and the second layer 108 of 50 psi or less. In various examples, compressing the assembly 102 includes a displacement-based first compression process, where the pressure is such that the TIM104 reaches a desired bond line thickness t Bl It is added to the first layer 106 and the second layer 108 until it is compressed.

[0052] In various examples, the relative liquid metal surface area coverage between TIM 104 and the first and second layers 106 and 108 can increase with compression. For example, the relative liquid metal surface area coverage after compression may be in the range of 1% to 100%, e.g., 1% to 5%, 5% to 10%, 10% to 30%, 30% to 50%, or may increase until the liquid metal surface area coverage reaches 100%. As used herein, “relative liquid metal surface area coverage” is the surface area covered by the liquid metal, normalized by the total contact surface area between TIM 104 and the first and second layers 108. The relative liquid metal surface area coverage can be measured using cross-sectioning, followed by optical imaging using a ZEISS Axio Zoom.V16, or confocal scanning acoustic microscopy using a Hitachi FineSAT III for CSAM.

[0053] After compression, the thickness of the joint line t of assembly 102 BlThe thickness of the bond wire t of assembly 102 may be 300 microns or less, for example, 250 microns or less, 200 microns or less, 150 microns or less, 145 microns or less, 140 microns or less, 125 microns or less, 100 microns or less, 80 microns or less, 70 microns or less, 50 microns or less, 40 microns or less, 35 microns or less, or 30 microns or less. Bl The thickness of the bond wire t of assembly 102 may be at least 1 micron, for example, at least 10 microns, at least 15 microns, at least 30 microns, at least 35 microns, at least 40 microns, at least 50 microns, at least 70 microns, at least 75 microns, at least 80 microns, at least 100 microns, at least 120 microns, at least 140 microns, at least 145 microns, or at least 200 microns. BL The micron size can be within the range of 1 micron to 300 microns, for example, 1 micron to 250 microns, 10 microns to 300 microns, 10 microns to 250 microns, 1 micron to 200 microns, 15 microns to 200 microns, 15 microns to 150 microns, 30 microns to 150 microns, 50 microns to 120 microns, 75 microns to 125 microns, or 15 microns to 100 microns.

[0054] D of liquid metal droplet 112 in TIM104 before application 90 The bond line thickness t Bl It can be larger than that. For example, the D of the liquid metal droplet 312 before application and / or compression process. 90 The bond line thickness t Bl Larger than, for example, bond line thickness t Bl Bond line thickness t is 1% larger than Bl Bond line thickness t is 2% larger than Bl 5% greater than, bond line thickness t Bl 10% larger than, bond line thickness t Bl 15% larger than, bond line thickness t Bl The bond line thickness t is 20% larger than Bl 30% larger than, bond line thickness t BlBond line thickness t is 40% larger than Bl 50% greater than, or bond line thickness t Bl It may be 75% larger than, for example. D of liquid metal droplet 112 before application and / or compression process. 90 The bond line thickness t Bl For example, a bond line thickness t that is less than 100% greater than Bl Bond line thickness t is 75% or less greater than Bl Bond line thickness t is 50% or less greater than Bl Bond line thickness t is 40% or less greater than Bl Bond line thickness t is 30% or less greater than Bl Bond line thickness t is 20% or less greater than Bl Bond line thickness t is 15% or less greater than Bl Bond line thickness t is 10% or less greater than Bl 5% or less greater than, or bond line thickness t Bl It may be 2% or less greater than the D of the liquid metal droplet 112 before application and / or compression process. 90 The bond line thickness t Bl A bond line thickness t that is 1% to 100% larger than Bl Bond line thickness t is 1% to 50% larger than Bl Bond line thickness t is 1% to 30% larger than Bl 2% to 30% greater than, or bond line thickness t Bl It can be within a range of 5% to 20% greater than that.

[0055] After compressing the circuit assembly, the TIM can cover at least 90% of the surface area of ​​the exposed side 106a of the first layer 106, for example, at least 95% of the surface area of ​​the exposed side 106a.

[0056] Compressing assembly 102 can apply force to TIM 104, deforming the liquid metal droplets 112 dispersed within the polymer component 110 of TIM 104. The compressive force can deform the liquid metal droplets 112 because the polymer component 110 remains conformable and movable. The liquid metal droplets 112 may remain in a liquid phase during deformation, requiring lower pressure for compression to achieve the desired deformation. For example, the liquid metal droplets 112 may be approximately spherical, as shown in Figure 1, and then approximately ellipsoidal, as shown in Figure 2. In various examples, the liquid metal droplets 112 before compression may have a first mean aspect ratio, and after compression, the liquid metal droplets 112 may have a second mean aspect ratio. The second mean aspect ratio may differ from the first mean aspect ratio. For example, the second mean aspect ratio may be greater than the first mean aspect ratio. The average aspect ratio may be the average ratio of the width of the liquid metal droplet 112 to the height of the liquid metal droplet 112. In various examples, the first aspect ratio may be 1, and the second aspect ratio may be greater than 1. In certain examples, the first aspect ratio may be in the range of 1 to 1.5. In certain examples, the second aspect ratio may be at least 0.5 greater than the first aspect ratio, for example, at least 1 greater than the first aspect ratio, at least 2 greater than the first aspect ratio, or at least 5 greater than the first aspect ratio, etc. In certain examples, the second aspect ratio may be at least 2 after the assembly 102 has been compressed, for example, at least 3 or at least 4 after the assembly 102 has been compressed, etc.

[0057] The width (e.g., the longest dimension) of the liquid metal droplet 112 may be substantially aligned with the longitudinal plane of the TIM 104 within the assembly 102, and the height of the liquid metal droplet 112 may be the thickness of the TIM 104 (e.g., the bond line thickness, d Bl) can be substantially aligned with the assembly 102. The width of the liquid metal droplet 112 may increase when the assembly 102 is compressed. For example, in a particular example, the diameter of the liquid metal droplet 112 before compression may be 200 μm (having a first aspect ratio of 1), and after compression to a bond line thickness of 100 μm, the liquid metal droplet can be deformed into an elliptical shape having a width of 400 μm (e.g., a second aspect ratio of 4).

[0058] In certain cases, the liquid metal droplet 112 can be aligned in substantially a single layer after compression, as shown in Figure 2. The single layer is the D of the liquid metal droplet 112. 50 and / or D 90 , and bond line thickness t Bl This can be achieved by selecting [this option]. Constituting liquid metal droplets 112 in a single layer can reduce the thermal resistance of TIM 104.

[0059] Liquid metal droplet 112 D 50 and / or D 90 The deformation of the liquid metal droplet 112, and the method of depositing the liquid metal droplet 112, can improve the thermal resistance of the TIM 104. For example, the TIM 104 has a thermal resistance of at least 0.5 (°K*mm 2 ) / W, for example, at least 1 (°K*mm 2 ) / W, at least 2(°K*mm 2 ) / W, at least 3(°K*mm 2 ) / W, at least 5(°K*mm 2 ) / W, or at least 10(°K*mm 2 It can include thermal resistance values ​​such as ) / W. TIM104 is 30(°K*mm 2 ) / W or less, for example, 20(°K*mm 2 ) / W or less, 15(°K*mm 2 ) / W or less, 10(°K*mm 2 ) / W or less, 9(°K*mm 2 ) / W or less, 8(°K*mm 2 ) / W or less, 7(°K*mm 2 ) / W or less, or 5(°K*mm 2It can include thermal resistance values ​​such as ) / W or less. TIM104 is 0.5(°K*mm 2 ) / W~30(°K*mm 2 ) / W, for example, 0.5(°K*mm 2 ) / W~20(°K*mm 2 ) / W, 0.5(°K*mm 2 ) / W~15(°K*mm 2 ) / W, 1(°K*mm 2 ) / W~10(°K*mm 2 ) / W, 2(°K*mm 2 ) / W~10(°K*mm 2 ) / W, or 2(°K*mm 2 ) / W~8(°K*mm 2 This can include thermal resistance values ​​within the range of ) / W, etc. Thermal resistance values ​​can be measured using a TIMA 5 instrument manufactured by NanoTest (Germany).

[0060] Composition of TIM104, D of liquid metal droplet 112 50 and / or D 90 The deformation of the liquid metal droplet 112, and the method of depositing the liquid metal droplet 112, can improve the thermal conductivity value of the TIM 104. For example, the TIM 104 may have an effective thermal conductivity value of at least 5 W / m*K, for example, at least 10 W / m*K, at least 12 W / m*K, at least 15 W / m*K, at least 17 W / m*K, or at least 20 W / m*K. The TIM may have an effective thermal conductivity value in the range of 5 W / m*K to 50 W / m*K, for example, 10 W / m*K to 40 W / m*K, or 10 W / m*K to 30 W / m*K. As used herein, effective thermal conductivity is calculated by dividing the thickness of the TIM by the thermal resistance of the TIM.

[0061] Depending on the application, TIM104 may or may not be cured. For example, TIM104 may be cured to thicken the TIM, which can increase the viscosity of polymer component 110. In certain examples, TIM may be cured to a solid. In various examples, TIM104 is cured after compressing the first layer 106 and the second layer 108 of assembly 102. Applying TIM104 at a lower viscosity can allow for more efficient installation and the ability to wet the surfaces of the first layer 106 and the second layer 108. Increasing the viscosity after application can allow TIM104 to resist pump-out and enhance removal of TIM104. In various examples, TIM104 may not be cured.

[0062] In various examples, the cured polymer component 110 is an elastomer. Curing the polymer component 110 can suppress pump-out from the liquid metal droplets 112 during the thermal cycling of the assembly 102 and can provide a mechanical bond between the first layer 106 and the second layer 108. In various examples, curing the TIM 104 may include crosslinking the liquid metal droplets 114 to the polymer component 110 using a functionalizing component. For example, the functionalizing component can bond to the liquid metal droplets 114 via a metal oxide, or the functionalizing component can chemically react with the polymer component 110 to form a bond.

[0063] Curing TIM104 may include at least one of the following: heating TIM104 (for example, in the case of a thermosetting polymer), adding a catalyst to TIM104, exposing TIM104 to air, cooling TIM104 (for example, in the case of a thermoplastic polymer), applying electromagnetic radiation (e.g., photopolymerization), and applying pressure to TIM104. Curing TIM104 can increase the viscosity of the TIM emulsion. For example, TIM104 may have a post-curing viscosity that is at least twice that of the pre-curing TIM, for example, at least three times, at least four times, or ten times the viscosity of the pre-curing TIM. For example, TIM104 can have cured viscosities exceeding 15,000 cP, such as exceeding 20,000 cP, 30,000 cP, 50,000 cP, 100,000 cP, 150,000 cP, 200,000 cP, 250,000 cP, 500,000 cP, 750,000 cP, 850,000 cP, 1,000,000 cP, 1,500,000 cP, 2,500,000 cP, 4,000,000 cP, or 5,000,000 cP. In various examples, TIM104 can be an adhesive. The polymer in TIM104 may be selected to reduce gas release of TIM104 during curing. In certain cases, TIM104 can be removed by solvent and / or exfoliation.

[0064] As used herein, the terms “curing” and “curing” refer to the chemical crosslinking of components in an emulsion or material applied to a substrate, or the increase in viscosity of components in an emulsion or material applied to a substrate. Therefore, the terms “curing” and “curing” do not encompass only the physical drying of the emulsion or material through solvent or carrier evaporation. In this regard, as used herein in examples involving thermosetting polymers, the term “cured” refers to the state of an emulsion or material in which components have chemically reacted to form new covalent bonds within the emulsion or material (e.g., new covalent bonds formed between the binder resin and the curing agent). As used herein in examples involving thermoplastic polymers, the term “cured” refers to the state of an emulsion or material in which the temperature of the thermoplastic polymer has decreased below its melting point, resulting in an increase in the viscosity of the emulsion or material. In examples involving both thermosetting and thermoplastic polymers, the term “cured” refers to one or both polymers curing as described herein.

[0065] In various other examples, the TIM according to this disclosure can be used in a system on a package. For example, a single horizontal TIM layer may be in contact with multiple dies on one side (e.g., an integrated circuit may comprise multiple dies, or multiple integrated circuits may be in contact with the same side of the TIM), and may be in contact with upper layers or multiple layers on different sides.

[0066] Those skilled in the art will recognize that the compositions, articles, methods, and accompanying considerations described herein are used as examples for conceptual clarity, and various configuration modifications are intended. Consequently, when used herein, the specific examples and accompanying considerations described are intended to represent a more general class. In general, the use of any specific example is intended to represent that class, and the exclusion of specific components (e.g., operations), devices, and objects should not be considered limiting.

[0067] Those skilled in the art will understand that, with respect to the attached claims, the operations listed therein can generally be performed in any order. Furthermore, while various operation flows are presented in the sequence, it should be understood that various operations can be performed in orders other than those illustrated, or simultaneously. Examples of such alternative orderings include, unless otherwise specified by the context, overlapping, interleaving, interrupting, rearranging, incrementing, preparing, complementing, simultaneous, reverse, or other variable orderings. Moreover, terms such as “responding to,” “related to,” or other past tense adjectives are generally not intended to exclude such variations unless otherwise specified by the context.

[0068] While various examples are described herein, many modifications, variations, substitutions, alterations, and equivalents of these examples may be implemented and conceived by those skilled in the art. Furthermore, if a material is disclosed with respect to a particular component, other materials may be used. Therefore, it should be understood that the foregoing description and the accompanying claims are intended to cover all such modifications and variations that fall within the scope of the disclosed embodiments. The following claims are intended to cover all such modifications and variations.

[0069] Various aspects of the present invention as disclosed herein include, but are not limited to, those listed in the following numbered clauses.

[0070] Clause 1. A thermal interface material comprising a polymer component, liquid metal droplets dispersed throughout the polymer component, wherein at least a portion of the liquid metal droplets includes an outer surface containing a metal oxide, and a functionalizing component bonded to at least a portion of the metal oxide by an acid.

[0071] Clause 2. The thermal interface material as described in Clause 1, wherein the acid is Brønsted-Lowry acid.

[0072] Clause 3. The thermal interface material according to Clause 1 or 2, wherein the acid contains at least one of an acid containing a sulfate group, an acid containing a nitrate group, an acid containing a phosphate group, an acid containing a chloride group, an acid containing a bromide group, an acid containing an iodide group, a carboxylic acid, and an acid containing a sulfonic acid group.

[0073] Clause 4. The thermal interface material according to any one of Clauses 1 to 3, wherein the acid contains at least one of sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, and carboxylic acid.

[0074] Clause 5. The thermal interface material according to any one of Clauses 1 to 4, wherein the acid is a monobasic acid.

[0075] Clause 6. The thermal interface material according to any one of Clauses 1 to 4, wherein the acid is a polybasic acid.

[0076] Clause 7. The thermal interface material according to any one of Clauses 1 to 6, wherein the concentration of the functionalized component on the surface of the liquid metal droplets is in the range of 1×10 -6 ~5 molecules / nm 2 Clause 8. The thermal interface material according to any one of Clauses 1 to 7, wherein the functionalized component further comprises a coupling agent covalently bonded to the acid.

[0077] Clause 9. The thermal interface material according to any one of Clauses 1 to 8, wherein the functionalized component further comprises a polymer chain covalently bonded to the acid.

[0078] Clause 10. The thermal interface material according to Clause 9, wherein the polymer chain has a molecular weight of at least 400 g / mol.

[0079]

[0080] ​Clause 11. The thermal interface material according to Clause 9 or 10, wherein the polymer chain comprises at least one of acrylic polymers, acrylate polymers, vinyl polymers, polyester polymers, polyurethane polymers, polybutadiene polymers, polyamide polymers, polyether polymers, polysiloxane polymers, hydrogenated silicon polymers, fluoropolymers, polyisoprene polymers, polystyrene polymers, polyepoxide polymers, and any two or more copolymers thereof.

[0081] Clause 12. Liquid metal droplets are within the range of 1 micron to 300 microns. 90 A thermal interface material as described in any one of clauses 1 to 11, including the thermal interface material described in any one of clauses 1 to 11.

[0082] Clause 13. A thermal interface material according to any one of Clauses 1 to 12, wherein the liquid metal droplets include at least one of gallium, gallium alloys, indium, indium alloys, tin, tin alloys, mercury, and mercury alloys.

[0083] Clause 14. A thermal interface material according to any one of Clauses 1 to 13, wherein the metal oxide comprises at least one of gallium oxide, indium oxide, tin oxide, iron oxide, mercury oxide, aluminum oxide, nickel oxide, zinc oxide, and copper oxide.

[0084] Clause 15. A thermal interface material according to any one of Clauses 1 to 14, wherein the metal oxide comprises gallium oxide, the liquid metal droplet comprises gallium or a gallium alloy, the acid is a carboxylic acid, and the functionalizing component further comprises a polymer chain covalently bonded to the carboxylic acid.

[0085] Clause 16. A thermal interface material according to any one of Clauses 1 to 15, wherein the liquid metal droplet has a melting point of 30 degrees Celsius or less.

[0086] Clause 17. A thermal interface material according to any one of Clauses 1 to 16, wherein the thermal interface material contains a first viscosity in the range of 1,000 cP to 850,000 cP as measured at 25°C.

[0087] Clause 18. A thermal interface material according to any one of Clauses 1 to 17, further comprising at least one of a catalyst, rigid particles, a coupling agent, and fumed silica.

[0088] Clause 19. A thermal interface material according to any one of Clauses 1 to 18, wherein the liquid metal droplets include a contact angle of 120 degrees or less.

[0089] Clause 20. A circuit assembly comprising: a first layer; a second layer; and a thermal interface material according to any one of Clauses 1 to 19, disposed in contact with and between the first and second layers.

[0090] Clause 21. The circuit assembly described in Clause 20, wherein the liquid metal droplet is substantially ellipsoidal.

[0091] Clause 22. The circuit assembly according to Clause 20 or 21, wherein the thickness of the bonding wire formed between the first layer and the second layer is 300 microns or less.

[0092] Clause 23. A circuit assembly according to any one of Clauses 20 to 22, wherein the first layer comprises at least one of a processor and an integrated heat spreader, and the second layer comprises at least one of a heat sink, an integrated heat spreader, and packaging.

[0093] Clause 24. A method comprising applying a thermal interface material described in any one of Clauses 1 to 19 onto a first layer of an assembly such that the thermal interface material is in contact with and between a first layer and a second layer of the assembly, and compressing the assembly, thereby deforming the liquid metal droplets, wherein the liquid metal droplets in the thermal interface material before application are D 90 A method comprising deforming a material such that the deformation is greater than the thickness of the bond line formed between the first layer and the second layer.

[0094] Clause 25. The method according to Clause 24, further comprising curing a thermal interface material after compressing the assembly, thereby forming a cured assembly.

[0095] Clause 26. The method according to Clause 25, wherein curing comprises crosslinking liquid metal droplets to polymer components using a functionalizing component.

[0096] Clause 27. An assembly produced by any one of Clauses 24-26.

[0097] Clause 28. A method for producing a thermal interface material, comprising: combining a polymer component and a liquid metal to form an intermediate mixture; dispersing the liquid metal throughout the polymer component in the intermediate mixture to form liquid metal droplets having an outer surface containing a metal oxide; and contacting the metal oxide with an acid to form a functionalized component bonded to at least a portion of the metal oxide.

[0098] Clause 29. The method according to Clause 28, wherein the acid was in contact with the metal oxide after the liquid metal had been dispersed throughout the polymer component.

[0099] Clause 30. The method according to Clause 28, wherein the acid is added before combining the polymer component and the liquid metal.

[0100] Clause 31. The method according to any one of Clauses 28 to 30, wherein the functionalizing component further comprises a polymer chain bonded to an acid.

[0101] Clause 32. A method for producing a thermal interface material according to any one of Clauses 1 to 19, comprising: combining a polymer component and a liquid metal to form an intermediate mixture; dispersing the liquid metal throughout the polymer component in the intermediate mixture to form liquid metal droplets having an outer surface containing a metal oxide; and contacting the metal oxide with an acid to form a functionalized component bonded to at least a portion of the metal oxide.

[0102] As used herein, the listing of elements “at least one of” means one of the elements or any combination of two or more of the listed elements. For example, “at least one of A, B, and C” means A only, B only, C only, A and B, A and C, B and C, or A, B, and C.

[0103] To provide an understanding of the compositions, structures, manufactures, functions, and / or operations of the present invention, including the disclosed compositions, coatings, and methods, various features and properties are described herein. It should be understood that the various features and properties of the present invention described herein can be combined in any preferred manner, whether such features and properties are expressly described herein in combination. The inventors and applicants expressly intend that such combinations of features and properties fall within the scope of the present invention as described herein. Thus, the claims can be amended to enumerate, in any combination, any features and properties expressly or essentially described herein, or otherwise expressly or essentially supported herein. Furthermore, the applicant reserves the right to amend the claims to affirmatively negate features and properties that may exist in the prior art, even if these features and properties are not expressly described herein. Therefore, any such amendment does not add new matter to the specification or claims and is subject to the requirements of written description, sufficiency of description, and added matter.

[0104] Any numerical range enumerated herein describes all subranges of the same numerical precision (i.e., having the same number of specified digits) that fall within the enumerated range. For example, the enumerated range "1.0 to 10.0" describes all subranges (including their upper and lower limits) from the enumerated minimum value of 1.0 to the enumerated maximum value of 10.0, such as "2.4 to 7.6," even if the range "2.4 to 7.6" is not explicitly enumerated in the text of this specification. Accordingly, the applicant reserves the right to amend this specification, including the claims, to explicitly enumerate any subranges of the same numerical precision that fall within the ranges explicitly enumerated herein. All such ranges are essentially described herein, and therefore any amendment to explicitly enumerate any such subranges shall be subject to the requirements of written description, sufficiency of description, and added matter.

[0105] Furthermore, unless explicitly specified or otherwise required by the context, all numerical parameters described herein (such as values, ranges, quantities, percentages, etc.) may be read as if preceded by the word "approximately," even if the word "approximately" does not explicitly appear before the numerical value. In addition, numerical parameters described herein should be interpreted by applying the reported number of significant figures, numerical precision, and standard rounding techniques. It should also be understood that numerical parameters described herein inevitably possess the inherent variability characteristics of the underlying measurement techniques used to determine the numerical value of the parameters.

[0106] While the numerical ranges and parameters describing the broad scope of this invention are approximations, the numerical values ​​described in specific examples are reported as accurately as possible. However, each numerical value inherently contains a certain degree of error, which is inevitably brought about by the standard variations found in each test measurement.

[0107] Throughout this specification, references to “various examples,” “several examples,” “one example,” and “examples” mean that certain features, structures, or characteristics described in relation to an example are included in that example. Therefore, the occurrence of phrases such as “various examples,” “several examples,” “one example,” and “in one example” in their usual place throughout this specification does not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics may be combined in any preferred manner in one or more examples. Therefore, certain features, structures, or characteristics illustrated or described in relation to one example may be combined, in whole or in part, with features, structures, or characteristics of another example or other examples, though not limited to these. Such modifications and variations are intended to be within the scope of these embodiments.

[0108] Any patent, publication, or other document identified herein is incorporated in whole by reference unless otherwise indicated, provided that the incorporated material does not conflict with any existing descriptions, definitions, statements, examples, or other disclosures expressly provided herein. Therefore, to the extent necessary, express disclosures provided herein take precedence over any conflicting material incorporated by reference. Any material, or any part thereof, incorporated by reference but conflicting with any existing definitions, statements, or other disclosures provided herein is incorporated only insofar as it does not create a conflict between the incorporated material and the existing disclosures. The applicant reserves the right to amend this specification to expressly enumerate any subject matter or part thereof incorporated by reference. Any amendment to this specification to add such incorporated subject matter shall be subject to the requirements of written description, sufficiency of description, and added subject matter.

[0109] While specific examples of the present invention have been described above for illustrative purposes, it will be apparent to those skilled in the art that many modifications of the details of the present invention can be made without departing from the present invention as defined in the appended claims.

[0110] This disclosure provides descriptions of various specific embodiments for the purpose of illustrating various aspects and / or potential uses thereof, but those skilled in the art should understand that variations and modifications will occur. Accordingly, it should be understood that the inventions or inventions described herein are at least as broad as they are claimed and not more narrowly defined by the specific illustrative embodiments provided herein.

[0111] It should be understood that the inventions described herein are not limited to the embodiments summarized in the summary or detailed description. Various other embodiments are described and illustrated herein.

Claims

1. A thermal interface material, Polymer components, A liquid metal droplet dispersed throughout the polymer component, wherein at least a portion of the liquid metal droplet includes an outer surface containing a metal oxide, A thermal interface material comprising a functionalizing component bonded to at least a portion of the metal oxide by an acid.

2. The thermal interface material according to claim 1, wherein the acid is Brønsted-Lowry acid.

3. The thermal interface material according to claim 1, wherein the acid comprises at least one of the following: an acid containing a sulfate group, an acid containing a nitrate group, an acid containing a phosphoric acid group, an acid containing a chloride group, an acid containing a bromide group, an acid containing an iodide group, a carboxylic acid, and an acid containing a sulfonic acid group.

4. The thermal interface material according to claim 1, wherein the acid comprises at least one of sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, and carboxylic acid.

5. The thermal interface material according to claim 1, wherein the acid is a monobasic acid.

6. The thermal interface material according to claim 1, wherein the acid is a polybasic acid.

7. The concentration of the functionalizing component on the surface of the liquid metal droplet is 1 × 10 －６ ~5 molecules / nm ２ A thermal interface material according to claim 1, which is within the range.

8. The thermal interface material according to claim 1, further comprising a coupling agent covalently bonded to the acid as the functionalizing component.

9. The thermal interface material according to claim 1, wherein the functionalizing component further comprises a polymer chain covalently bonded to the acid.

10. The thermal interface material according to claim 9, wherein the polymer chain contains a molecular weight of at least 400 g / mol.

11. The thermal interface material according to claim 9, wherein the polymer chain comprises at least one of acrylic polymers, acrylate polymers, vinyl polymers, polyester polymers, polyurethane polymers, polybutadiene polymers, polyamide polymers, polyether polymers, polysiloxane polymers, hydrogenated silicon polymers, fluoropolymers, polyisoprene polymers, polystyrene polymers, polyepoxide polymers, and any two or more copolymers thereof.

12. The liquid metal droplets are in the range of 1 micron to 300 microns. ９０ The thermal interface material according to claim 1, including the above.

13. The thermal interface material according to claim 1, wherein the liquid metal droplet comprises at least one of gallium, gallium alloy, indium, indium alloy, tin, tin alloy, mercury, and mercury alloy.

14. The thermal interface material according to claim 1, wherein the metal oxide comprises at least one of gallium oxide, indium oxide, tin oxide, iron oxide, mercury oxide, aluminum oxide, nickel oxide, zinc oxide, and copper oxide.

15. The thermal interface material according to claim 1, wherein the metal oxide comprises gallium oxide, the liquid metal droplet comprises gallium or a gallium alloy, the acid is a carboxylic acid, and the functionalizing component further comprises a polymer chain covalently bonded to the carboxylic acid.

16. The thermal interface material according to claim 1, wherein the liquid metal droplet has a melting point of 30 degrees Celsius or lower.

17. The thermal interface material according to claim 1, wherein the thermal interface material contains a first viscosity in the range of 1,000 cP to 850,000 cP as measured at 25°C.

18. The thermal interface material according to claim 1, further comprising at least one of a catalyst, rigid particles, a coupling agent, and fumed silica.

19. The thermal interface material according to claim 1, wherein the liquid metal droplets have a contact angle of 120 degrees or less.

20. It is an assembly, The first layer and, The second layer, A circuit assembly comprising: a thermal interface material according to claim 1, which is in contact with and disposed between the first layer and the second layer.

21. The assembly according to claim 20, wherein the liquid metal droplet is substantially ellipsoidal.

22. The assembly according to claim 20, wherein the thickness of the bond line formed between the first layer and the second layer is 300 microns or less.

23. The assembly according to claim 20, wherein the first layer comprises at least one of a processor and an integrated heat spreader, and the second layer comprises at least one of a heat sink, an integrated heat spreader, and packaging.

24. It is a method, Applying the thermal interface material according to claim 1 onto the first layer of the assembly such that the thermal interface material is in contact with and between the first and second layers of the assembly, The assembly is compressed, thereby deforming the liquid metal droplets, and the D of the liquid metal droplets in the thermal interface material before application. ９０ A method comprising, however, deforming the material to a degree greater than the thickness of the bond line formed between the first layer and the second layer.

25. The method according to claim 24, further comprising compressing the assembly, then curing the thermal interface material to form a cured assembly.

26. The method according to claim 25, wherein the curing includes crosslinking the liquid metal droplets to a polymer component using a functionalizing component.

27. An assembly produced by the method described in claim 24.

28. A method for manufacturing a thermal interface material, Combining polymer components and liquid metals to form an intermediate mixture, The liquid metal is dispersed throughout the polymer component in the intermediate mixture, thereby forming liquid metal droplets having an outer surface containing a metal oxide. A method comprising contacting the metal oxide with an acid to form a functionalized component bonded to at least a portion of the metal oxide.

29. The method according to claim 28, wherein the acid is in contact with the metal oxide after the liquid metal has been dispersed throughout the polymer component.

30. The method according to claim 28, wherein the acid is added before combining the polymer component and the liquid metal.

31. The method according to claim 28, wherein the functionalizing component further comprises a polymer chain bonded to the acid.

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