Thermal interface material, integrated circuit formed by thermal interface material and application method of thermal interface material

Abstract

The invention provides a thermal interface material, an integrated circuit formed by the thermal interface material and an application method of the thermal interface material. The thermal interface material includes 5 to 30% by volume of a polymer component and at least 70% by volume of liquid metal droplets, all based on the total volume of the thermal interface material. The polymer component has a first polymer having a molecular weight in the range of 400 g / mol to 400000 g / mol. Liquid metal droplets are dispersed throughout the polymer component.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims priority to U.S. Provisional Patent Application Serial No. 63 / 482,449, filed on January 31, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The invention relates to a thermal interface material, an integrated circuit formed by using the same and an application method thereof. 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 CPU packages to thermally connect the CPU package's integrated heat sink (IHS) to a heat sink. Various types of TIMs are available. However, the use of some TIMs presents challenges. Summary of the Invention

[0004] In one general aspect, the present invention relates to a thermal interface material comprising 5% to 30% by volume of a polymer component and at least 70% by volume of liquid metal droplets, all based on the total volume of the thermal interface material. The polymer component comprises a first polymer having a molecular weight in the range of 400 g / mol to 400,000 g / mol. The liquid metal droplets are dispersed throughout the polymer component.

[0005] In another general aspect, the present invention relates to a thermal interface material comprising 5% to 30% by volume of a polymer component and at least 70% by volume of liquid metal droplets, all based on the total volume of the thermal interface material. The polymer component may include a polyalkylene glycol having a molecular weight in the range of 400 g / mol to 4000 g / mol. The liquid metal droplets are dispersed throughout the polymer component. In various examples, the polyalkylene glycol includes at least one of polyethylene glycol, polypropylene glycol, polybutylene glycol, and copolymers thereof, such as polypropylene glycol. In certain examples, the polymer component also includes a second polymer that is miscible with the polyalkylene glycol. For example, the second polymer may include at least one of an epoxy polymer, an acrylate polymer, a vinyl polymer, and a silicon hydride polymer, such as an epoxy polymer containing hydroxyl end groups. In certain examples, the polymer component is configured to extend the polymer chains of the second polymer in response to heating to a temperature of at least 50°C.

[0006] The present invention can provide low contact resistance at material interfaces and low thermal resistance through the TIM. Low contact resistance can be achieved by applying the polymer in a conformal state, allowing the polymer and liquid metal droplets to conform to the surface of the layer to achieve the desired contact resistance. The liquid metal droplets can achieve the low thermal resistance of the TIM. The TIM can be removed to allow for use during component testing and / or replacement of components as needed. These and other benefits achievable from various embodiments of the present invention will be apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The features and advantages of various examples of the present invention and the manner in which they are achieved will become more apparent and the examples will be better understood by referring to the following description of examples taken in conjunction with the accompanying drawings, in which:

[0008] Figure 1 is a perspective view of a circuit assembly according to the present disclosure after deposition of a thermal interface material; and

[0009] Figure 2 By compression Figure 1 A side view of circuit components forming an integrated circuit.

[0010] Corresponding reference numerals indicate corresponding parts throughout the several views.The examples set forth herein illustrate certain examples in one form and should not be construed as limiting the scope of the examples in any way. DETAILED DESCRIPTION

[0011] Certain exemplary aspects of the present invention will now be described to provide an overall understanding of the composition, function, manufacture, and principles of use of the compositions and methods disclosed herein. One or more examples of these aspects are shown in the accompanying drawings. One or more persons skilled in the art will understand that the compositions, articles, and methods specifically described herein and shown in the accompanying drawings are non-limiting exemplary aspects, and that the scope of the various examples of the present invention is limited only by the claims. Features shown or described in conjunction with one exemplary aspect may be combined with features of other aspects. Such modifications and variations are intended to be included within the scope of the present invention.

[0012] Applying a thermal interface material (TIM) to a circuit assembly, with the TIM positioned between the integrated heat sink (IHS) and the heat sink, may require balancing the thermal resistance through the TIM and the contact resistance at the material interface. For example, a polymer material may have low contact resistance at the material interface but high thermal resistance throughout the material. A solid metal may have low thermal resistance through the material but high contact resistance at the material interface. In addition, some solid materials (polymer or metal) may require significant pressure during installation to achieve the desired contact resistance. Furthermore, it may be desirable to remove the TIM after application so that it can be used to test the component and / or replace it.

[0013] Therefore, the inventors provide a thermal interface material, an integrated circuit formed therewith, and an application method thereof in various examples, which can effectively remove the TIM after installation while achieving effective thermal conductivity of the TIM. Based on the total volume of the thermal interface material, the TIM includes a polymer component with a volume percentage of 5% to 30% and a liquid metal droplet with a volume percentage of at least 70%. The liquid metal droplets are dispersed throughout the polymer component. The polymer component includes a first polymer having a molecular weight in the range of 400g / mol to 400000g / mol, for example, 400g / mol to 200000g / mol, 400g / mol to 100000g / mol, 400g / mol to 50000g / mol, 400 / mol to 10000g / mol or 400g / mol to 4000g / mol. The molecular weight can be measured using gel permeation chromatography. As used herein, "molecular weight" refers to the number average molecular weight M n .

[0014] The terms "polymer" and "polymerization" as used in this specification refer to prepolymers, oligomers, homopolymers and copolymers. "Prepolymer" as used in this specification refers to a polymer precursor that can be further reacted or polymerized through one or more reactive groups to form a higher molecular weight or cross-linked state.

[0015] The first polymer can be at least one of a polymer adhesive, a thermosetting polymer, and a thermoplastic polymer. As used herein, the term "thermosetting" refers to a polymer that is irreversibly "cured" when cured or cross-linked, wherein the polymer chains of the polymer components are linked together by covalent bonds, and the covalent bonds are typically caused by, for example, heat or radiation. In various examples, the curing or cross-linking reaction can be carried out under ambient conditions. Once cured or cross-linked, the thermosetting polymer may not flow when heated, the viscosity may increase irreversibly, and / or may be insoluble in conventional solvents. As used herein, the term "thermoplastic" refers to a polymer comprising a polymer component, wherein the polymer chains of the components are not linked (e.g., cross-linked) by covalent bonds, so that liquid flow can occur when heated, and is soluble in conventional solvents. In certain embodiments, the polymer can be an elastomer (e.g., rubbery, soft, elastic) or rigid (e.g., glassy). For example, the polymer can be an elastomer.

[0016] The thermosetting polymer may include at least one of a crosslinking agent, which may include, for example, aminoplasts, polyisocyanates (including blocked isocyanates), polyepoxides, beta-hydroxyalkylamides, polyacids, anhydrides, organometallic acid functional materials, polyamines, polyethylene, polysilicon hydrides, polyols, polyacid chlorides, polyhalides, and polyamides. The polymer may have functional groups reactive with the crosslinking agent.

[0017] The thermosetting polymer may include at least one of an acrylic polymer, an acrylate polymer, a vinyl polymer, a polyester polymer, a polyurethane polymer, a polybutadiene polymer, a polyamide polymer, a polyether polymer, a polysiloxane polymer (e.g., poly(dimethylsiloxane)), a silicon hydride polymer, a fluoropolymer, a polyisoprene polymer (e.g., rubber), and copolymers thereof. The functional group on the thermosetting polymer may be selected from any of a variety of reactive functional groups, including, for example, at least one of a carboxylic acid group, an amino group, an epoxy group, a hydroxyl group, a mercapto group, a carbamate group, an amide group, a urea group, an isocyanate group (including a blocked isocyanate group), a vinyl group, a silicon hydride group, an acyl chloride group, an acrylate group, a halide group, and a thiol group.

[0018] In various examples, the first polymer includes a polyether polymer, such as a polyalkylene glycol. The polyalkylene glycol may include at least one of polyethylene glycol, polypropylene glycol, polybutylene glycol, and copolymers thereof. For example, the polyalkylene glycol may include polypropylene glycol.

[0019] 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. Thus, the terms "curing" and "curing" encompass more than just physical drying of an emulsion or material by evaporation of a solvent or carrier. In this regard, the term "curing" as used in the examples herein involving thermosetting polymers refers to a state of an emulsion or material in which a component of the emulsion or material undergoes a chemical reaction to form new covalent bonds in the emulsion or material (e.g., new covalent bonds formed between a binder resin and a curing agent).

[0020] The thermoplastic polymer may include at least one of propylene-ethylene copolymer, styrene-butadiene-styrene, and styrene-ethylene-butylene-styrene. The melting point of the polymer may be at least 100 degrees Celsius, such as at least 120 degrees Celsius, at least 150 degrees Celsius, or at least 200 degrees Celsius.

[0021] The polymer binder may be a polyether binder.

[0022] In various examples, the polymer component may include a second polymer. The second polymer may be miscible with the first polymer. For example, the second polymer may be miscible with a polyalkylene glycol. The second polymer may include at least one of an epoxy polymer, an acrylate polymer, a vinyl polymer, and a silicon hydride polymer. For example, the second polymer may include an epoxy polymer containing hydroxyl end groups, such as polyalkylene glycol diglycidyl ether.

[0023] The polymer component may include a composition suitable for effectively removing the TIM after installation while achieving effective thermal conductivity during use. For example, the polymer component may include 1% to 50% by weight of a first polymer and 50% to 99% by weight of a second polymer, all based on the total weight of the polymer component. In various examples, the polymer component may include 5% to 30% by weight of the first polymer and 70% to 95% by weight of the second polymer, all based on the total weight of the polymer component. In certain examples, the polymer component may include 1% to 50% by weight of a polyalkylene glycol and 50% to 99% by weight of a polyalkylene glycol diglycidyl ether, or 5% to 30% by weight of a polyalkylene glycol and 70% to 95% by weight of a polyalkylene glycol diglycidyl ether, all based on the total weight of the polymer component.

[0024] The polymer component can be configured to cure at a temperature of at least 50 degrees Celsius, such as at least 60 degrees Celsius, at least 70 degrees Celsius, at least 80 degrees Celsius, or at least 90 degrees Celsius. For example, the polymer component can be configured to cure at a temperature in the range of 50 degrees Celsius to 150 degrees Celsius, such as 60 degrees Celsius to 120 degrees Celsius. For example, the second polymer component can be configured to undergo chain extension in response to heating to a temperature of at least 50 degrees Celsius. Chain extension of the second polymer can increase its molecular weight, thereby increasing the viscosity of the TIM.

[0025] The liquid metal droplets used for the TIM may include at least one of gallium, a gallium alloy, indium, an indium alloy, tin, a tin alloy, mercury, and an amalgam. The melting point of the liquid metal droplets may be no greater than 30 degrees Celsius, such as no greater than 25 degrees Celsius, no greater than 20 degrees Celsius, no greater than 15 degrees Celsius, no greater than 10 degrees Celsius, no greater than 5 degrees Celsius, no greater than 0 degrees Celsius, or no greater than -10 degrees Celsius. The melting point of the liquid metal droplets may be at least -40 degrees Celsius, such as 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. The melting point of the liquid metal droplet may be in the 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 may be measured at 1 atmosphere absolute pressure. In some embodiments, the TIM may include gallium indium tin (Galinstan), which has a melting point of -19°C.

[0026] TIMs can be prepared by forming an emulsion of a polymer and liquid metal droplets such that the liquid metal droplets are well dispersed throughout the polymer. For example, the polymer and bulk liquid metal can be mixed together using at least one of a high shear mixer, a centrifugal mixer, by shaking in a container, using a mortar and pestle, and sonication. For more details on exemplary methods of forming emulsions and liquid metal droplets, see: (1) published PCT WO / 2019 / 136252, entitled “Methods for synthesizing thermally conductive stretchable polymer composites”; (2) published U.S. application US2017 / 0218167, entitled “Polymer composites with liquid metal inclusions”; (3) U.S. Patent No. 10,777,483, entitled “Methods, apparatus, and assemblies for thermal interconnect layers”; (4) U.S. Provisional Patent No. 63 / 268,134, entitled “Thermal interface materials, integrated circuit assemblies, and methods for thermal interconnect layers”; (5) published PCT WO 2022 / 204689, entitled “Methods, devices and assemblies for thermal connection layers using thermal interface materials containing rigid particles”; and (6) U.S. Provisional Application No. 63 / 479,879, entitled “A method for manufacturing a thermal interface material, a thermal interface material formed therefrom, and an integrated circuit formed therefrom,” the entire contents of which are incorporated herein by reference.

[0027] The ingredients and / or mixing techniques can be selected to achieve a viscosity of less than 850,000 cP (centipoise), such as 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 ingredients and / or mixing techniques can be selected to achieve a viscosity of the TIM of at least 1,000 cP, such as at least 2,000 cP, at least 5,000 cP, or at least 10,000 cP. Appropriate ingredients and / or mixing techniques can be selected to achieve a TIM viscosity within the range of 1,000 cP to 850,000 cP, such as 2,000 cP to 750,000 cP or 2,000 cP to 500,000 cP. The viscosity of a TIM emulsion can be measured using a parallel plate (40 mm) rheometer at 25 degrees Celsius, a frequency of 10 rad / s, and a strain of 5%. Selecting viscosity requires balancing the installation pressure, which may increase with higher viscosities, with the ability to resist undesirable rapid spreading and pumping during application of the TIM and during operation.

[0028] The TIM may include at least 1% liquid metal droplets by volume of the TIM, for example, at least 5% liquid metal droplets, at least 10% liquid metal droplets, at least 20% liquid metal droplets, at least 30% liquid metal droplets, at least 40% liquid metal droplets, at least 50% liquid metal droplets, or at least 60% liquid metal droplets, or at least 70% liquid metal droplets, or at least 80% liquid metal droplets, or at least 90% liquid metal droplets, all based on the total volume of the liquid metal droplets. The TIM may include no greater than 95% liquid metal droplets by volume of the TIM, such as no greater than 93% liquid metal droplets, no greater than 90% liquid metal droplets, no greater than 80% liquid metal droplets, no greater than 70% liquid metal droplets, no greater than 60% liquid metal droplets, no greater than 50% liquid metal droplets, no greater than 40% liquid metal droplets, no greater than 30% liquid metal droplets, no greater than 20% liquid metal droplets, or no greater than 10% liquid metal droplets, all based on the total volume of the TIM. The TIM can include liquid metal droplets in a range of 1% to 95% by volume of the TIM, such as 5% to 93% liquid metal droplets, 50% to 93% liquid metal droplets, 60% to 93% liquid metal droplets, 70% to 95% liquid metal droplets, or 70% to 93% liquid metal droplets, all based on the total volume of the TIM. The amount of liquid metal droplets can be selected while balancing the desired elasticity and desired effective thermal conductivity of the TIM.

[0029] 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 Before compression, the D of the liquid metal droplet 50 The diameter of the liquid metal droplet may be at least 1 micron, 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, all before compression. 50 It may be no greater than 300 microns, for example, no greater than 250 microns, no greater than 200 microns, no greater than 150 microns, no greater than 120 microns, no greater than 100 microns, no greater than 90 microns, no greater than 80 microns, no greater than 70 microns, no greater than 60 microns, no greater than 50 microns, no greater than 40 microns, no greater than 35 microns, no greater than 30 microns, no greater than 20 microns, no greater than 10 microns, or no greater than 5 microns before compression. For example, the D of a liquid metal droplet may be no greater than 300 microns, no greater than 20 microns, no greater than 10 microns, or no greater than 5 microns. 50The particle size of the liquid metal droplets may be in the range of 1 μm to 300 μm, such as 5 μm to 300 μm, 150 μm to 250 μm, 5 μm to 150 μm, 15 to 150 μm, 35 μm to 150 μm, 35 μm to 70 μm, or 5 μm to 100 μm, all measured before compression. In various embodiments, the composition and / or mixing technique may be selected to achieve an average particle size of the liquid metal droplets that is larger than the D of the rigid particles in the TIM. 50 (if present), e.g., D 50 At least 1% larger, at least 2% larger, at least 5% larger, at least 10% larger, or at least 20% larger.

[0030] As used herein, D X The measurement can be made using a microscope (e.g., an optical microscope). This dimension can be the diameter of a spherical particle or the length along the largest dimension of an elliptical or other irregularly shaped particle. As used herein, the "D" of a particle is X ” means that X% of the volume of particles have the smaller diameter.

[0031] Before compression, the D of the liquid metal droplet 90 The diameter of the liquid metal droplet may be at least 1 micron, 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. 90 It may be no greater than 300 microns, for example, no greater than 250 microns, no greater than 200 microns, no greater than 150 microns, no greater than 120 microns, no greater than 100 microns, no greater than 90 microns, no greater than 80 microns, no greater than 70 microns, or no greater than 50 microns before compression. 90 It can be in the range of 1 micron to 300 microns, such as 5 microns to 300 microns, 150 microns to 250 microns, 10 microns to 200 microns, 15 microns to 150 microns, 35 microns to 150 microns, 35 microns to 120 microns or 50 microns to 100 microns, all of which are measured before compression.

[0032] The TIM may optionally include other components, such as at least one of rigid particles, a catalyst, fumed silica, and a coupling agent. The rigid particles may include at least one of iron, an iron alloy (e.g., steel), vanadium, a vanadium alloy, niobium, a niobium alloy, titanium, a titanium alloy, copper, a copper alloy (e.g., bronze), aluminum, an aluminum alloy, a rigid polymer, glass, and a ceramic (e.g., alumina). The rigid particles may resist 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), such as 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 may be measured according to ASTM E111-17. The TIM can include 0.1% to 30% rigid particles by total volume of the TIM, such as 0.1% to 10% rigid particles, 0.1% to 5% rigid particles, 1% to 10% rigid particles, or 1% to 5% rigid particles, all based on the total volume of the TIM.

[0033] In various examples, the polymer component may include 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.

[0034] In certain examples, the polymer component can include 0.1 to 5 weight percent fumed silica, based on the total weight of the polymer component.

[0035] The D of the rigid particles in TIM can be selected 50 , to achieve the desired bond line thickness in the component. The average particle size of the rigid particles can be at least 1 micron, such as 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. The D of the rigid particles 50 The particle diameter may be no greater than 150 microns, for example, no greater than 125 microns, no greater than 120 microns, no greater than 100 microns, no greater than 90 microns, no greater than 80 microns, no greater than 70 microns, no greater than 60 microns, no greater than 50 microns, no greater than 40 microns, no greater than 35 microns, no greater than 30 microns, no greater than 20 microns, no greater than 10 microns, or no greater than 5 microns. For example, the D of the rigid particle may be no greater than 150 microns, for example, no greater than 125 microns, no greater than 120 microns, no greater than 100 microns, or no greater than 90 microns, no greater than 80 microns, no greater than 70 microns, no greater than 60 microns, no greater than 50 microns, no greater than 40 microns 50It can be in the range of 1 micron to 150 microns, such as 15 to 150 microns, 5 microns to 125 microns, 35 microns to 125 microns, 35 microns to 70 microns, or 50 microns to 70 microns.

[0036] TIM can be applied to various layers and devices. Figure 1-Figure 2 The description is made with reference to circuit components, but is not limited to circuit components and can also be applied to other devices. Figure 1 , a method according to the present disclosure includes depositing a TIM 104 according to the present disclosure between a first layer 106 of a circuit assembly 102 and a second layer 108 of the circuit assembly 102. As shown, the TIM 104 includes an emulsion of liquid metal droplets 112 and a polymer 110.

[0037] As used in this specification, particularly with respect to layers, films, or materials, the terms "on," "over," and "above," and variations thereof (e.g., "applied," "formed," "deposited," "disposed," "located," etc.) refer to being applied, formed, deposited, disposed, or otherwise located on, but not necessarily in contact with, the surface of a substrate. For example, a TIM being "deposited" on a substrate or "deposited" between two elements does not preclude the presence of another layer or other layers of the same or different composition between the applied TIM and the substrate. Similarly, a second layer being "deposited" on a first layer does not preclude the presence of another layer or other layers of the same or different composition between the deposited second layer and the deposited TIM.

[0038] Depositing the TIM 104 may include at least one of dispensing, extruding (e.g., through a nozzle, such as a circular nozzle, a fan nozzle, or other nozzle shapes), applying with an implement (e.g., a brush, a squeegee), stenciling, 3D printing, and screen printing. The TIM 104 may be deposited in a conformal state such that the TIM 104 can adapt to the surfaces of the first layer 106 and the second layer 108 to achieve a desired level of surface contact therebetween. In various examples, the TIM 104 may be applied directly to the first layer 106, after which the second layer 108 may be applied directly to the TIM 104. In various other examples, the TIM 104 may be applied directly to the second layer 108, after which the first layer 106 may be applied directly to the TIM 104. In some examples, the TIM 104 may be applied to the first layer 106 and the second layer 108, after which the first layer 106 may be applied together with the second layer 106. In various examples, after depositing TIM 104 and compression circuit assembly 102, TIM 104 can be in direct contact with first layer 106 and second layer 108. In some examples, application of TIM 104 can be limited to a surface of first layer 106, allowing efficient use of TIM 104.

[0039] TIM 104 can be dispensed from a container and applied to the layer in a conformable state. TIM 104 can be stored in the container prior to use. TIM 104 can be in a conformable state within the container. The container can include at least one of a pillow pack, a syringe, a beaker, a jar, a bottle, and a drum. In various examples, the container can be a ready-to-use dispensing device, such as a pillow pack or a syringe. In some examples, TIM 104 can be stored and can be used after the emulsion is generated without storage.

[0040] Prior to compressing the circuit assembly 102, the TIM 104 may be applied to at least 1% of the surface area of ​​the exposed side 106a of the first layer 106, such as at least 2%, at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, or at least 50% of the total surface area of ​​the exposed side 106a of the first layer 106. For example, prior to compressing the circuit assembly 102, the TIM 104 may be applied to a range of 1% to 100% of the surface area of ​​the exposed side 106a of the first layer 106, such as 2% to 100%, 5% to 90%, or 5% to 80% of the total surface area of ​​the exposed side 106a of the first layer 106.

[0041] The first layer 106 may be a heat generating electronic component (e.g., an integrated circuit such as a processor, an ASIC, and / or a system on a chip (SOC)) and / or thermally connected to the heat generating electronic component. The second layer 108 may be an upper layer that may conduct heat. The first layer 106 and the second layer 108 may each be at least one of a processor, a heat sink (e.g., a fin, a fan, liquid cooling, a cold plate), an integrated heat sink, and a package. In various examples, the first layer 106 may include a processor and the second layer 108 may include at least one of a heat sink, an integrated heat sink, and a package. In certain examples, the first layer 106 may include an integrated heat sink and the second layer may include at least one of a heat sink, an integrated heat sink, and a package.

[0042] After depositing the TIM 104, the method includes compressing the circuit assembly 102, thereby deforming the liquid metal droplets 112 and forming the integrated circuit 202. For example, referring to Figure 1-Figure 2 , first layer 106 and second layer 108 may be compressed together. For example, compressing circuit assembly 102 may include applying a first pressure of at least 1 psi, such as at least 5 psi, at least 10 psi, at least 15 psi, or at least 20 psi, to first layer 106 and second layer 108. In various examples, the first pressure may be in a range of 1 psi to 50 psi, such as 10 psi to 50 psi or 10 psi to 30 psi.

[0043] In various examples, the relative liquid metal surface area coverage between the TIM 104 and the first and second layers 106, 108 can be increased by compression. For example, the relative liquid metal surface area coverage after compression can be in a range of 1% to 100%, such as 1% to 5%, 5% to 10%, 10% to 30%, 30% to 50%, or increasing until the liquid metal surface area coverage reaches 100%. As used herein, "relative liquid metal area coverage" refers to the surface area covered by liquid metal, normalized by the total contact surface area between the TIM 104 and the first and second layers 106, 108. The relative liquid metal area coverage can be measured using cross-sections followed by optical imaging using a confocal scanning acoustic microscope and CSAM using a Hitachi FineSAT III.

[0044] After compression, the bond wire thickness t of the circuit assembly 102 Bl The thickness of the bonding wire of the circuit component 102 may be no greater than 300 microns, such as no greater than 250 microns, no greater than 200 microns, no greater than 200 microns, no greater than 150 microns, no greater than 145 microns, no greater than 140 microns, no greater than 125 microns, no greater than 100 microns, no greater than 80 microns, no greater than 70 microns, no greater than 50 microns, no greater than 40 microns, no greater than 35 microns, or no greater than 30 microns. Bl The bond wire thickness t of the circuit component 102 may be at least 1 μm, for example, at least 10 μm, at least 15 μm, at least 30 μm, at least 35 μm, at least 40 μm, at least 50 μm, at least 70 μm, at least 75 μm, at least 80 μm, at least 100 μm, at least 120 μm, at least 140 μm, at least 145 μm, at least 150 μm, at least 200 μm, at least 300 μm, or at least 400 μm. Bl It can be in 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.

[0045] Before application, the D of the liquid metal droplet 112 in the TIM 104 90 May be greater than the bond wire thickness t Bl For example, before the application and / or compression process, the D of the liquid metal droplet 312 90 Can be greater than the bonding wire thickness t Bl , for example, than the bonding wire thickness t Bl 1% larger than the bond wire thickness t Bl2% larger than the bond wire thickness t Bl 5% larger than the bond wire thickness t Bl 10% larger than the bond wire thickness t Bl 15% larger than the bond wire thickness t Bl 20% larger than the bond wire thickness t Bl 30% larger than the bond wire thickness t Bl 40% larger than the bond wire thickness t Bl 50% larger, or greater than the bond wire thickness t Bl 75% larger. Before the application and / or compression process, the D of the liquid metal droplet 112 90 Can be no greater than the bonding wire thickness t Bl 100%, for example, not greater than the bond wire thickness t Bl 75% of the bonding wire thickness t Bl 50% of the bonding wire thickness t Bl 40% of the bonding wire thickness t Bl 30% of the bonding wire thickness t Bl 20% of the bonding wire thickness t Bl 15% of the bonding wire thickness t Bl 10% of the bonding wire thickness t Bl 5% or no more than the bonding wire thickness t Bl 2%. Before the application and / or compression process, the D of the liquid metal droplet 112 90 The thickness of the bonding wire can be Bl 1% to 100% greater, for example, than the bond wire thickness t Bl 1% to 50% larger than the bond wire thickness t Bl 1% to 30% larger than the bond wire thickness t Bl 2% to 30% larger, or greater than the bond wire thickness t Bl 5% to 20% larger.

[0046] After compressing the circuit assembly, the TIM may cover at least 90% of the surface area of ​​the exposed side 106 a of the first layer 106 , such as at least 95% of the surface area of ​​the exposed side 106 a .

[0047] Compressing the circuit assembly 102 can exert force on the TIM 104 and can deform the liquid metal droplets 112 dispersed within the polymer 110 of the TIM 104. Because the polymer 110 is still conformable and movable, the compressive force can deform the liquid metal droplets 112. The liquid metal droplets 112 can be in a liquid phase during the deformation process, so that compression requires lower pressure to achieve the desired deformation. For example, Figure 1 As shown, the liquid metal droplet 112 may be substantially spherical, and thereafter as Figure 2 As shown, the liquid metal droplets 112 may be generally elliptical in shape. In various examples, the liquid metal droplets 112 before compression may have a first average aspect ratio, and the liquid metal droplets 112 after compression may have a second average aspect ratio. The second average aspect ratio may be different from the first average aspect ratio. For example, the second average aspect ratio may be greater than the first average aspect ratio. The average aspect ratio may be the average ratio of the width of the liquid metal droplets 112 to the height of the liquid metal stream 112. In various examples, the first aspect ratio may be 1, and the second aspect ratio may be greater than 1. In some embodiments, the first aspect ratio may be in a range of 1 to 1.5. In some embodiments, 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. In some embodiments, after compression of the circuit assembly 102, the second aspect ratio may be at least 2, for example, at least 3 or at least 4 after compression of the circuit assembly 102.

[0048] The width (eg, longest dimension) of the liquid metal droplet 112 may be substantially aligned with the longitudinal plane of the TIM 104 in the circuit assembly 102, and the height of the liquid metal droplet 112 may be substantially aligned with the longitudinal plane of the TIM 104 (eg, the bond wire thickness t BL ) is substantially aligned with the thickness of the bond wire. The width of the liquid metal droplet 112 can increase when the circuit assembly 102 is compressed. For example, in some examples, the diameter of the liquid metal droplet before compression can be 200 μm (a first aspect ratio of 1), and after being compressed to a bond wire thickness of 100 μm, the liquid metal droplet can be deformed into an elliptical shape with a width of 400 μm (e.g., a second aspect ratio of 4).

[0049] In some examples, the liquid metal droplets 112 may be arranged substantially into a single layer after compression, e.g. Figure 2 The monolayer can be formed by selecting the D of the liquid metal droplet 112 50 and / or D 90 and the bonding wire thickness t BL Arranging the liquid metal droplets 112 in a single layer can reduce the thermal resistance of the TIM 104 .

[0050] D of liquid metal droplet 112 50 and / or D 90 The deformation of the liquid metal droplet 112 and the deposition method of the liquid metal droplet 112 can improve the thermal resistance of the TIM 104. For example, the TIM 104 can include at least 5 (°K*mm 2 ) / W thermal resistance, 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 ) / W. TIM 104 may include no more than 30(°K*mm 2 ) / W thermal resistance, for example, not more than 20(°K*mm 2 ) / W, not more than 15(°K*mm 2 ) / W, not more than 10(°K*mm 2 ) / W, not more than 9(°K*mm 2 ) / W, not more than 8(°K*mm 2 ) / W, not more than 7(°K*mm 2 ) / W, or not more than 5(°K*mm 2 ) / W. The thermal resistance of TIM 104 can be 0.5(°K*mm 2 ) / W to 30(°K*mm 2 ) / W, for example 0.5(°K*mm 2 ) / W to 20(°K*mm 2 ) / W、0.5(°K*mm 2 ) / W to 15(°K*mm 2 ) / W、1(°K*mm 2 ) / W to 10(°K*mm 2 ) / W、2(°K*mm 2 ) / W to 10(°K*mm 2 ) / W, or 2(°K*mm 2 ) / W to 8(°K*mm 2 ) / W. Thermal resistance can be measured using the TIMA5 instrument from NanoTest (Germany).

[0051] D of liquid metal droplet 112 50 and / or D 90 The deformation of the liquid metal droplets 112 and the deposition method of the liquid metal droplets 112 can increase the thermal conductivity value of the TIM 104. For example, the TIM 104 can include an effective thermal conductivity value of at least 5 W / m*K, such as 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 can include an effective thermal conductivity value in the range of 5 W / m*K to 50 W / m*K, such as 10 W / m*K to 40 W / m*K or 10 W / m*K to 30 W / m*K. As used herein, the effective thermal conductivity is equal to the thickness of the TIM divided by the thermal resistance of the TIM.

[0052] TIM 104 may or may not be cured, depending on the application. For example, TIM 104 may be cured to thicken TIM 104, which may increase the viscosity of polymer 110. Applying TIM 104 at a lower viscosity may allow for more efficient installation and the ability to wet the surfaces of first layer 106 and second layer 108. Increasing the viscosity after application may make TIM 104 resistant to pumping out and enhance removal of TIM 104.

[0053] Curing TIM 104 may include at least one of heating TIM 104, adding a catalyst to TIM 104, exposing TIM 104 to air, applying electromagnetic radiation (e.g., photopolymerization), and applying pressure to TIM 105. For example, the polymer component in TIM 104 may be cured. Curing TIM 104 may increase the viscosity of the TIM emulsion. For example, the viscosity of TIM 104 after curing may be at least twice the viscosity of the TIM before curing, such as at least three, four, or ten times the viscosity of the TIM before curing. For example, the viscosity of the TIM 104 after curing may be greater than 15,000 cP, such as greater than 20,000 cP, greater than 30,000 cP, greater than 50,000 cP, greater than 100,000 cP, greater than 150,000 cP, greater than 200,000 cP, greater than 250,000 cP, greater than 500,000 cP, greater than 750,000 cP, greater than 850,000 cP, greater than 1,000,000 cP, greater than 1,500,000 cP, greater than 2,500,000 cP, greater than 4,000,000 cP, or greater than 5,000,000 cP.

[0054] The circuit assembly can be used with a TIM 104, which can facilitate heat transfer between the first layer 106 and the second layer 108. The TIM 104 can be removed from at least one of the first layer 106 and / or the second layer 108. For example, the TIM 104 can be scraped off the first layer 106 and / or the second layer 108. In various examples, the TIM 104 can be removed using a solvent, such as isopropyl alcohol. In certain examples, the TIM 104 can be removed by scraping and using a solvent. Due to the increased viscosity after curing, the removal of the TIM 104 can be more efficient.

[0055] In various other examples, a TIM according to the present disclosure can be used in a system-on-package. For example, a single horizontal TIM layer can contact multiple dies on one side (e.g., an integrated circuit can include multiple dies, or multiple integrated circuits can contact the same side of the TIM) and contact one or more upper layers on the other side.

[0056] Those skilled in the art will recognize that for the sake of conceptual clarity, the compositions, articles, methods, and the accompanying discussions thereof described herein are used as examples, and various configuration modifications are contemplated. Therefore, as used herein, the specific examples and accompanying discussions set forth are intended to represent their more general categories. In general, the use of any particular example is intended to represent its category, and the exclusion of specific components (e.g., operations), devices, and objects should not be considered limiting.

[0057] With respect to the appended claims, those skilled in the art will understand that the operations described therein may generally be performed in any order. Furthermore, although the various operational flows are presented in a sequential order, it should be understood that the various operations may be performed in an order other than the order shown, or may be performed simultaneously. Unless the context dictates otherwise, examples of such alternative sequences may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant sequences. Furthermore, unless the context dictates otherwise, terms such as "responsive to," "related to," or other past tense adjectives generally do not preclude variations of such terms.

[0058] Although various examples are described herein, many modifications, variations, substitutions, changes, and equivalents may be made to these examples, which will be apparent to those skilled in the art. Furthermore, where materials are disclosed for certain components, other materials may be used. Therefore, it should be understood that the foregoing description and the appended claims are intended to cover all such modifications and variations that fall within the scope of the disclosed examples. The following claims are intended to cover all such modifications and variations.

[0059] Various aspects of the invention according to this disclosure include, but are not limited to, those listed in the following numbered clauses.

[0060] Item 1. A thermal interface material comprising: a polymer component in an amount of 5 to 30 volume percent based on the total volume of the thermal interface material, the polymer component comprising a polyalkylene glycol having a molecular weight in a range of 400 g / mol to 4000 g / mol; and at least 70 volume percent of liquid metal droplets based on the total volume of the thermal interface material, wherein the liquid metal droplets are dispersed throughout the polymer component.

[0061] Item 2. The thermal interface material according to Item 1, wherein the polyalkylene glycol comprises at least one of polyethylene glycol, polypropylene glycol, polybutylene glycol, and copolymers thereof.

[0062] Item 3. The thermal interface material of Item 1, wherein the polyalkylene glycol comprises polypropylene glycol.

[0063] Clause 4. The thermal interface material of any one of clauses 1 to 3, wherein the polymer component further comprises a second polymer.

[0064] Item 5. The thermal interface material of Item 4, wherein the second polymer is miscible with the polyalkylene glycol.

[0065] Item 6. The thermal interface material of Item 4, wherein the second polymer comprises at least one of an epoxy polymer, an acrylate polymer, a vinyl polymer, and a silicon hydride polymer.

[0066] Clause 7. The thermal interface material of clause 4, wherein the second polymer comprises an epoxy polymer comprising hydroxyl end groups.

[0067] Clause 8. The thermal interface material of clause 4, wherein the second polymer comprises polyalkylene glycol diglycidyl ether.

[0068] Item 9. A thermal interface material according to Item 8, wherein the polymer component comprises: 1 to 50 weight percent of polyalkylene glycol based on the total weight of the polymer component; and 50 to 99 weight percent of polyalkylene glycol diglycidyl ether based on the total weight of the polymer component.

[0069] Clause 10. The thermal interface material of any one of clauses 4 to 9, wherein the polymer component is configured to cure at a temperature of at least 50°C.

[0070] Clause 11. The thermal interface material of any one of clauses 4 to 10, wherein the thermal interface material comprises a first viscosity in a range of 1000 cP to 850000 cP measured at 25°C prior to curing.

[0071] Clause 12. The thermal interface material of clause 11, wherein the thermal interface material has a second viscosity after curing that is at least twice the first viscosity.

[0072] Clause 13. The thermal interface material of any one of clauses 4 to 12, wherein the polymer component is configured to extend polymer chains of the second polymer in response to heating to a temperature of at least 50°C.

[0073] Clause 14. The thermal interface material of any one of clauses 1 to 13, further comprising at least one of a catalyst and rigid particles.

[0074] Item 15. The thermal interface material according to any one of Items 1 to 14, wherein the polymer component further comprises a coupling agent in an amount of 0.1% to 0.5% by weight based on the total weight of the polymer component.

[0075] Item 16. The thermal interface material according to any one of Items 1 to 15, wherein the polymer component further comprises 0.1 to 5 weight percent of fumed silica based on the total weight of the polymer component.

[0076] Clause 17. The thermal interface material of any one of clauses 1 to 16, wherein the polymer component further comprises a catalyst.

[0077] Clause 18. The thermal interface material of any one of clauses 1 to 17, wherein the liquid metal droplets comprise gallium, a gallium alloy, indium, an indium alloy, tin, a tin alloy, mercury, an amalgam, or a combination thereof.

[0078] Item 19. The thermal interface material according to any one of Items 1 to 18, wherein the melting point of the liquid metal droplets is no greater than 30 degrees Celsius.

[0079] Item 20. A thermal interface material according to any one of items 1 to 19, wherein the polymer component further comprises a crosslinker selected from aminoplasts, polyisocyanates, polyepoxides, β-hydroxyalkylamides, polyacids, anhydrides, organometallic acid functional materials, polyamines, polyethylene, polysilicon hydrides, polyols, polyacid chlorides, polyhalides and polyamides.

[0080] Clause 21. A circuit assembly comprising: a first layer; a second layer; and the thermal interface material of any one of clauses 1 to 20, disposed in contact with and between the first layer and the second layer.

[0081] Clause 22. The circuit assembly of clause 21, wherein the liquid metal droplets are generally elliptical.

[0082] Clause 23. The circuit assembly of any one of clauses 21 to 22, wherein a bond wire formed between the first layer and the second layer has a thickness no greater than 300 microns.

[0083] Clause 24. The circuit assembly of any of clauses 21 to 23, wherein the first layer comprises a processor and the second layer comprises at least one of a heat sink, an integrated heat sink, a cooling plate, a fan, a liquid cooling system, and a package.

[0084] Clause 25. The circuit assembly of any of clauses 21 to 24, wherein the first layer comprises an integrated heat sink and the second layer comprises at least one of a heat sink, a cooling plate, a fan, a liquid cooling system, an integrated heat sink, and a package.

[0085] Clause 26. A method comprising: depositing a thermal interface material according to any one of clauses 1 to 20 between a first layer of an integrated circuit assembly and a second layer of an integrated circuit assembly; and compressing the integrated circuit assembly to deform the liquid metal droplets, wherein before the compression is applied, the D 90 is greater than a thickness of a bonding wire formed between the first layer and the second layer.

[0086] Clause 27. The method of clause 26, further comprising curing the thermal interface material after compressing the integrated circuit assembly to form a cured assembly.

[0087] Clause 28. The method of clause 27, wherein curing comprises heating the thermal interface material to at least 50°C.

[0088] Clause 29. The method of clause 27, wherein curing comprises heating the thermal interface material and the first layer to at least 50°C.

[0089] Clause 30. The method of any one of clauses 26 to 29, further comprising removing the thermal interface material from at least one of the first layer and the second layer.

[0090] Clause 31. An integrated circuit component produced by the method according to any one of clauses 26 to 30.

[0091] Item 32. A thermal interface material comprising: 5% to 30% by volume of a polymer component, based on the total volume of the thermal interface material, the polymer component having a first polymer having a molecular weight in the range of 400 g / mol to 400,000 g / mol and a second polymer component, wherein the second polymer is configured to undergo chain extension in response to heating to a temperature of at least 50°C; and at least 70% by volume of liquid metal droplets, based on the total volume of the thermal interface material, wherein the liquid metal droplets are dispersed throughout the polymer component.

[0092] Clause 33. The thermal interface material of clause 32, wherein the second polymer is miscible with the first polymer.

[0093] Clause 34. The thermal interface material of any one of clauses 32 to 33, wherein the second polymer comprises at least one of an epoxy polymer, an acrylate polymer, a vinyl polymer, and a silicon hydride polymer.

[0094] Clause 35. The thermal interface material of any one of clauses 32 to 34, wherein the first polymer comprises at least one of a polymer binder, a thermosetting polymer, and a thermoplastic polymer.

[0095] Item 36. A thermal interface material according to any one of items 32 to 35, wherein the first polymer comprises at least one of an acrylic polymer, an acrylate polymer, a vinyl polymer, a polyester polymer, a polyurethane polymer, polybutadiene, a polyamide polymer, a polyether polymer, a polysiloxane polymer, a silicon hydride polymer, a fluoropolymer, a polyisoprene polymer, and copolymers thereof.

[0096] Item 37. A thermal interface material according to any one of items 32 to 36, wherein the polymer component includes: a first polymer in an amount of 1% to 50% by weight based on the total weight of the polymer component; and a second polymer in an amount of 50% to 99% by weight based on the total weight of the polymer component.

[0097] Clause 38. The thermal interface material of any one of clauses 32 to 37, wherein the polymer component is configured to cure at a temperature of at least 50°C.

[0098] Clause 39. The thermal interface material of any one of clauses 32 to 38, wherein the thermal interface material comprises a first viscosity in a range of 1000 cP to 850000 cP measured at 25°C prior to curing.

[0099] Clause 40. The thermal interface material of clause 39, wherein the thermal interface material has a second viscosity after curing that is at least twice the first viscosity.

[0100] Clause 41. The thermal interface material of any of clauses 32 to 40, wherein the polymer component is configured to extend polymer chains of the second polymer in response to heating to a temperature of at least 50°C.

[0101] Item 42. A thermal interface material according to any one of Items 32 to 41, wherein the polymer component further comprises a crosslinker selected from aminoplasts, polyisocyanates, polyepoxides, β-hydroxyalkylamides, polyacids, anhydrides, organometallic acid functional materials, polyamines, polyethylene, polysilicon hydrides, polyols, polyacid chlorides, polyhalides, and polyamides.

[0102] Clause 43. A circuit assembly comprising: a first layer; a second layer; and the thermal interface material of any one of clauses 32 to 42, disposed in contact with and between the first layer and the second layer.

[0103] Clause 44. A method comprising: depositing a thermal interface material according to any one of clauses 32 to 42 between a first layer of an integrated circuit assembly and a second layer of an integrated circuit assembly; and compressing the integrated circuit assembly to deform the liquid metal droplets, wherein before the compression is applied, the D 90 is greater than a thickness of a bonding wire formed between the first layer and the second layer.

[0104] As used herein, "at least one" in a list of elements refers to one element or any combination of two or more elements in the list. For example, "at least one of A, B, and C" refers to only A; only B; only C; A and B; A and C; B and C; or A, B, and C.

[0105] Various features and characteristics are described in this specification to facilitate an understanding of the composition, structure, production, function, and / or operation of the present invention, including the disclosed compositions, coatings, and methods. It should be understood that the various features and characteristics of the present invention described in this specification may be combined in any suitable manner, regardless of whether such features and characteristics are explicitly described in this specification as a combination. The inventors and applicants expressly intend that such combinations of features and characteristics be included within the scope of the invention described in this specification. Accordingly, the claims may be amended to recite, in any combination, any features and characteristics explicitly or inherently described in this specification, or any features and characteristics otherwise explicitly or inherently supported by this specification. Furthermore, applicants reserve the right to amend the claims to expressly disclaim features and characteristics that may exist in the prior art, even if such features and characteristics are not explicitly described in this specification. Accordingly, any such amendments will not add new matter to the specification or claims and will comply with the requirements of written description, sufficiency of description, and addition of matter.

[0106] Any numerical range cited in this specification describes all subranges with the same numerical precision (i.e., designated digits with the same numerical value) contained within the cited range. For example, a cited range of "1.0 to 10.0" describes all subranges between (and including) the cited minimum value of 1.0 and the cited maximum value of 10.0, such as "2.4 to 7.6," even if the specification does not explicitly cite a range of "2.4 to 7.6." Therefore, applicants reserve the right to amend this specification (including the claims) to expressly state any subranges with the same numerical precision contained within the ranges explicitly stated in this specification. All of these ranges are inherently described in this specification, and therefore amendments to expressly recite any such subranges would comply with the requirements of written description, adequacy of description, and added content.

[0107] In addition, unless otherwise expressly stated or the context requires otherwise, all numerical parameters described in this specification (e.g., parameters expressing values, ranges, amounts, percentages, etc.) can be understood as being preceded by the word "about" even if the word "about" does not explicitly appear before the number. In addition, the numerical parameters described in this specification should be interpreted based on the number of reported significant digits, numerical precision, and application of conventional rounding techniques. It should also be understood that the numerical parameters described in this specification necessarily have the inherent variability characteristics of the underlying measurement technology used to determine their numerical values.

[0108] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0109] Throughout this specification, references to “various examples,” “some examples,” “an example,” “an example,” etc., mean that a particular feature, structure, or characteristic described in connection with that example is included in the example. Thus, phrases such as “in various examples,” “in some examples,” “in an example,” and “in an example” that appear throughout this specification do not necessarily all refer to the same example. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more examples. Thus, particular features, structures, or characteristics shown or described in connection with one example may be combined, in whole or in part, with features, structures, or characteristics of another example without limitation. Such modifications and variations are intended to be encompassed within the scope of the present examples.

[0110] Unless otherwise stated, any patent, publication, or other document mentioned in this specification is incorporated herein by reference in its entirety, but only to the extent that the incorporated material does not conflict with existing descriptions, definitions, statements, examples, or other disclosure materials expressly set forth in this specification. Therefore, to the extent necessary, the disclosure expressly set forth in this specification supersedes any conflicting material incorporated by reference. Any material or portion thereof incorporated into this specification by reference that conflicts with existing definitions, statements, or other disclosure materials set forth herein is incorporated only to the extent that there is no conflict between the incorporated material and the existing disclosure materials. Applicants reserve the right to amend this specification to expressly recite any subject matter or portion thereof incorporated by reference. Amendments to this specification to add such incorporated subject matter will comply with the requirements of written description, sufficiency of description, and addition of content.

[0111] While specific examples of the present invention have been described above for purposes of illustration, it will be appreciated by those skilled in the art that various modifications may be made to the details of the invention without departing from the invention as defined in the appended claims.

[0112] Although the present disclosure provides descriptions of various specific aspects to illustrate various aspects of the present disclosure and / or its potential applications, it should be understood by those skilled in the art that various variations and modifications may be made. Therefore, the invention described herein should be understood to be at least as broad as the claims and not to be more narrowly defined by the specific illustrative aspects provided herein.

[0113] It should be understood that the invention described in this specification is not limited to the examples outlined in the abstract or detailed description. Various other aspects are also described and exemplified herein.

Claims

1. A thermal interface material comprising: 5% to 30% by volume of a polymer component based on the total volume of the thermal interface material, the polymer component comprising a polyalkylene glycol having a molecular weight in a range of 400 g / mol to 4000 g / mol; as well as The thermal interface material comprises at least 70% by volume of liquid metal droplets based on the total volume of the thermal interface material, wherein the liquid metal droplets are dispersed throughout the polymer component.

2. The thermal interface material according to claim 1, wherein The polyalkylene glycol includes at least one of polyethylene glycol, polypropylene glycol, polybutylene glycol and copolymers thereof.

3. The thermal interface material according to claim 1, wherein The polyalkylene glycol includes polypropylene glycol.

4. The thermal interface material according to claim 1, wherein The polymer component also includes a second polymer.

5. The thermal interface material according to claim 4, wherein: The second polymer is miscible with the polyalkylene glycol.

6. The thermal interface material according to claim 4, wherein: The second polymer includes at least one of an epoxy polymer, an acrylate polymer, a vinyl polymer, and a silicon hydride polymer.

7. The thermal interface material according to claim 4, wherein: The second polymer comprises an epoxy polymer comprising hydroxyl end groups.

8. The thermal interface material according to claim 4, wherein: The second polymer includes polyalkylene glycol diglycidyl ether.

9. The thermal interface material according to claim 8, wherein: The polymer component includes: 1 to 50 weight percent of a polyalkylene glycol, based on the total weight of the polymer component; and The weight percentage of the polyalkylene glycol diglycidyl ether is 50% to 99% based on the total weight of the polymer component.

10. The thermal interface material according to claim 4, wherein The polymer component is configured to cure at a temperature of at least 50°C.

11. The thermal interface material according to claim 4, wherein: The thermal interface material comprises a first viscosity within a range of 1,000 cP to 850,000 cP measured at 25° C. prior to curing.

12. The thermal interface material according to claim 11, wherein: The thermal interface material has a second viscosity after curing that is at least twice the first viscosity.

13. The thermal interface material according to claim 4, wherein The polymer component is configured to extend the polymer chains of the second polymer in response to heating to a temperature of at least 50°C.

14. The thermal interface material of claim 1, further comprising at least one of a catalyst and rigid particles.

15. The thermal interface material according to claim 1, wherein The polymer component further comprises a coupling agent in an amount of 0.1 to 0.5 weight percent based on the total weight of the polymer component.

16. The thermal interface material according to claim 1, wherein The polymer component further comprises 0.1 to 5 weight percent of fumed silica based on the total weight of the polymer component.

17. The thermal interface material according to claim 1, wherein The polymer component also includes a catalyst.

18. The thermal interface material according to claim 1, wherein The liquid metal droplets include gallium, gallium alloy, indium, indium alloy, tin, tin alloy, mercury, mercury alloy or a combination thereof.

19. The thermal interface material according to claim 1, wherein The melting point of the liquid metal droplet is no greater than 30 degrees Celsius.

20. The thermal interface material according to claim 1, wherein The polymer component also includes a crosslinker selected from aminoplasts, polyisocyanates, polyepoxides, beta-hydroxyalkylamides, polyacids, anhydrides, organometallic acid functional materials, polyamines, polyethylene, polysilicon hydrides, polyols, polyacid chlorides, polyhalides, and polyamides.

21. A circuit assembly comprising: First floor; Second floor; as well as The thermal interface material of claim 1, disposed in contact with and between the first layer and the second layer.

22. The circuit assembly of claim 21, wherein: The liquid metal droplets are generally elliptical in shape.

23. The circuit assembly of claim 21, wherein: The thickness of the bonding wire formed between the first layer and the second layer is no greater than 300 micrometers.

24. The circuit assembly of claim 21, wherein: The first layer includes a processor, and the second layer includes at least one of a heat sink, an integrated heat sink, a cold plate, a fan, a liquid cooling system, and a package.

25. The circuit assembly of claim 21, wherein: The first layer includes an integrated heat sink, and the second layer includes at least one of a heat sink, a cold plate, a fan, a liquid cooling system, an integrated heat sink, and a package.

26. A method comprising: depositing the thermal interface material according to claim 1 between a first layer of an integrated circuit assembly and a second layer of the integrated circuit assembly; as well as The integrated circuit component is compressed to deform the liquid metal droplet, wherein before the compression is applied, the D of the liquid metal droplet in the thermal interface material is 90 is greater than a thickness of a bonding wire formed between the first layer and the second layer.

27. The method of claim 26, further comprising curing the thermal interface material after compressing the integrated circuit assembly to form a cured assembly.

28. The method according to claim 27, wherein The curing includes heating the thermal interface material to at least 50°C.

29. The method according to claim 27, wherein The curing includes heating the thermal interface material and the first layer to at least 50°C.

30. The method of claim 27, further comprising removing the thermal interface material from at least one of the first layer and the second layer.

31. An integrated circuit component produced by the method of claim 26.

32. A thermal interface material comprising: 5% to 30% by volume of a polymer component, based on the total volume of the thermal interface material, the polymer component having a first polymer having a molecular weight in a range of 400 g / mol to 400,000 g / mol and a second polymer component, wherein the second polymer is configured to undergo chain extension in response to heating to a temperature of at least 50° C.; and The thermal interface material comprises at least 70% by volume of liquid metal droplets based on the total volume of the thermal interface material, wherein the liquid metal droplets are dispersed throughout the polymer component.

33. The thermal interface material according to claim 32, wherein The second polymer is miscible with the first polymer.

34. The thermal interface material according to claim 32, wherein The second polymer includes at least one of an epoxy polymer, an acrylate polymer, a vinyl polymer, and a silicon hydride polymer.

35. The thermal interface material according to claim 32, wherein The first polymer includes at least one of a polymer binder, a thermosetting polymer, and a thermoplastic polymer.

36. The thermal interface material according to claim 32, wherein The first polymer includes at least one of acrylic polymers, acrylate polymers, vinyl polymers, polyester polymers, polyurethane polymers, polybutadiene, polyamide polymers, polyether polymers, polysiloxane polymers, silicon hydride polymers, fluoropolymers, polyisoprene polymers, and copolymers thereof.

37. The thermal interface material according to claim 32, wherein The polymer component includes: 1 to 50 weight percent of a first polymer, based on the total weight of the polymer component; and The weight percentage of the second polymer is 50% to 99% based on the total weight of the polymer component.

38. The thermal interface material according to claim 32, wherein The polymer component is configured to cure at a temperature of at least 50°C.

39. The thermal interface material according to claim 32, wherein The thermal interface material comprises a first viscosity within a range of 1,000 cP to 850,000 cP measured at 25° C. prior to curing.

40. The thermal interface material according to claim 39, wherein The thermal interface material has a second viscosity after curing that is at least twice the first viscosity.

41. The thermal interface material according to claim 32, wherein The polymer component is configured to extend the polymer chains of the second polymer in response to heating to a temperature of at least 50°C.

42. The thermal interface material of claim 32, wherein: The polymer component also includes a crosslinker selected from aminoplasts, polyisocyanates, polyepoxides, beta-hydroxyalkylamides, polyacids, anhydrides, organometallic acid functional materials, polyamines, polyethylene, polysilicon hydrides, polyols, polyacid chlorides, polyhalides, and polyamides.

43. A circuit assembly comprising: First floor; Second floor; as well as The thermal interface material of claim 32, disposed in contact with and between the first layer and the second layer.

44. A method comprising: depositing the thermal interface material of claim 32 between a first layer of an integrated circuit assembly and a second layer of an integrated circuit assembly; as well as The integrated circuit component is compressed to deform the liquid metal droplet, wherein before the compression is applied, the D of the liquid metal droplet in the thermal interface material is 90 is greater than a thickness of a bonding wire formed between the first layer and the second layer.

Images