Thermal interface material, integrated circuit assembly and method for thermally connecting layers - Patents.com

Abstract

A thermal interface material (TIM), integrated circuit assembly, and method for thermally connecting layers are provided. The TIM includes a polymer component and liquid metal droplets dispersed throughout the polymer component. The polymer component includes a first polymer and at least one of a second polymer, a third polymer, and a fourth polymer. The first polymer includes a vinyl-terminated polydimethylsiloxane having a molecular weight (MW) of <30,000 g / mol. The second polymer includes a vinyl-terminated polydimethylsiloxane having a MW of ≥30,000 g / mol. The third polymer includes an alkyl-terminated polydimethylsiloxane having a MW of ≥30,000 g / mol. The fourth polymer includes polybutadiene. The TIM has a strain limit of at least 100%, and the TIM has a lap shear strength of at least 1 MPa.

Description

[Technical field]

[0001] The present disclosure relates to thermal interface materials, integrated circuit assemblies, and methods for thermally connecting layers. [Background technology]

[0002] 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 die to the integrated heat spreader (IHS) of the CPU package. Various types of TIMs exist and can be used. However, current TIMs present challenges. Summary of the Invention

[0003] In one general aspect, the invention is directed to an integrated circuit assembly including an integrated circuit die, a top layer, and a thermal interface material disposed in contact with the integrated circuit die and the top layer, where the thermal interface material is between the integrated circuit die and the top layer. The thermal interface material includes 8% to 70% by volume of a polymer component, based on a total volume of the thermal interface material, and at least 30% by volume of liquid metal droplets, based on a total volume of the thermal interface material. The liquid metal droplets are dispersed throughout the polymer component. The polymer component includes 5% to 99% by weight, based on a total weight of the polymer component, of a first polymer including a vinyl-terminated polydimethylsiloxane, and at least one of 5% to 95% by weight of a second polymer, 1% to 25% by weight of a third polymer, and 5% to 20% by weight of a fourth polymer, all based on a total weight of the polymer component. The second polymer includes a vinyl-terminated polydimethylsiloxane, and the third polymer includes an alkyl-terminated polydimethylsiloxane. The first polymer has a molecular weight of less than 30,000 g / mol, the second polymer has a molecular weight of at least 30,000 g / mol, and the third polymer has a molecular weight of at least 30,000 g / mol. The fourth polymer comprises polybutadiene, where the thermal interface material, when cured, has a strain limit of at least 100% and where the thermal interface material has a lap shear strength of at least 1 MPa.

[0004] In another general aspect, the invention is directed to a method that includes applying a thermal interface material onto an integrated circuit die such that the thermal interface material is between the integrated circuit die and a top layer of a circuit assembly. The thermal interface material includes 8% to 70% by volume of a polymer component, based on a total volume of the thermal interface material, and at least 30% by volume of liquid metal droplets, based on a total volume of the thermal interface material. The liquid metal droplets are dispersed throughout the polymer component. The polymer component includes 5% to 99% by weight, based on a total weight of the polymer component, of a first polymer including a vinyl-terminated polydimethylsiloxane, and at least one of 5% to 95% by weight of a second polymer, 1% to 25% by weight of a third polymer, and 5% to 20% by weight of a fourth polymer, based on a total weight of the polymer component. The second polymer includes a vinyl-terminated polydimethylsiloxane, and the third polymer includes an alkyl-terminated polydimethylsiloxane. The first polymer has a molecular weight of less than 30,000 g / mol, the second polymer has a molecular weight of at least 30,000 g / mol, and the third polymer has a molecular weight of at least 30,000 g / mol. The fourth polymer includes polybutadiene. Wherein the thermal interface material has a strain limit of at least 100% when cured. Compressing the integrated circuit assembly, thereby deforming the liquid metal droplets, where an average particle size of the liquid metal droplets in the thermal interface material prior to application is greater than a bond line distance formed between the die and the top layer in a cured assembly formed therefrom. The method includes curing the thermal interface material, thereby forming a cured assembly, wherein the thermal interface material has a lap shear strength of at least 1 MPa.

[0005] The present invention can provide low contact resistance and strong adhesion at the material interface, low thermal resistance through the material, and desirable stretchability. Low contact resistance can be enabled by application of the polymer in an uncured state so that the polymer and liquid metal droplets can conform to the surface of the layer to achieve the desired contact resistance. Low thermal resistance through the material can be enabled by the liquid metal droplets, including the size and / or shape of the liquid metal droplets. Strong adhesion and stretchability can be enabled by the composition of the polymer components. In addition, the methods described herein may require less pressure to install compared to methods that rely on application of the polymer in an uncured state. Furthermore, curing the polymer can inhibit pumping from the liquid metal droplets. These and other advantages realizable from various embodiments of the present invention will be apparent from the following description. [Brief description of the drawings]

[0006] The features and advantages of various embodiments of the present invention, as well as the manner in which they are accomplished, will become more apparent and the embodiments will be better understood by reference to the following description of the embodiments, given by way of example in conjunction with the accompanying drawings, in which:

[0007] [Figure 1] FIG. 1 is a schematic diagram of a container containing a TIM emulsion according to the present disclosure.

[0008] [Figure 2A] 1 is a cross-sectional side view of an integrated circuit assembly including a TIM according to the present disclosure.

[0009] [Figure 2B] 1 is a cross-sectional side view of an integrated circuit assembly including a TIM according to the present disclosure.

[0010] [Figure 3A] FIG. 2B is a detailed view of region 3A of the integrated circuit assembly of FIG. 2A prior to compressing the integrated circuit assembly.

[0011] [Figure 3B] 3B is the integrated circuit assembly of FIG. 3A after compressing the integrated circuit assembly.

[0012] Corresponding reference characters indicate corresponding parts throughout the several views. The examples described herein illustrate certain particular embodiments in one form and such examples should not be construed as limiting the scope of the embodiments in any manner. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Certain exemplary aspects of the present invention are described herein to provide a general understanding of the principles and methods of the compositions, functions, manufacture, and use of the compositions disclosed herein. One or more examples of these aspects are illustrated in the accompanying figures. Those skilled in the art will appreciate that the compositions, articles, and methods specifically described herein and illustrated in the accompanying figures are non-limiting exemplary aspects, and the scope of the various examples of the present invention is defined only by the claims. Features illustrated or described in connection 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.

[0014] Applying a material to an integrated circuit die of an integrated circuit assembly such that the material is between the integrated circuit die and the integrated heat spreader (IHS) may require balancing the thermal resistance through the material, the contact resistance at the material interface, the adhesion of the material, and the stretchability of the material. For example, a polymeric material may have low contact resistance at the material interface, but high thermal resistance through 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 large pressure during installation to achieve the desired contact resistance. Furthermore, some materials may not achieve the desired adhesion, which may lead to failure of the formed assembly, and / or some materials may not stretch as desired and therefore may peel off from the substrate, which may warp during operation of the integrated circuit. Thus, the present invention provides, in various embodiments, an integrated circuit assembly and method for thermally connecting two layers that can provide low contact resistance and strong adhesion at the material interface, low thermal resistance through the material, and desirable stretchability. An integrated circuit assembly according to the present disclosure may include a thermal interface material (TIM) that includes a polymer component with liquid metal droplets dispersed through the polymer.

[0015] As used herein, the terms "polymer" and "polymeric" refer to prepolymers, oligomers, and both homopolymers and copolymers. As used herein, "prepolymer" refers to a polymer precursor that is capable of further reaction or polymerization through a reactive group or groups to form a higher molecular weight or crosslinked state.

[0016] The TIM can comprise at least 8% by volume of the polymer component, based on the total volume of the TIM, e.g., at least 10% by volume of the polymer, at least 15% by volume of the polymer, at least 20% by volume of the polymer, at least 25% by volume of the polymer component, at least 30% by volume of the polymer component, at least 35% by volume of the polymer component, at least 40% by volume of the polymer component, at least 45% by volume of the polymer component, or at least 50% by volume of the polymer component, etc., all based on the total volume of the TIM. The TIM can comprise no more than 70% by volume of the polymer component, based on the total volume of the TIM, e.g., no more than 65% by volume of the polymer component, no more than 60% by volume of the polymer component, no more than 55% by volume of the polymer component, no more than 50% by volume of the polymer component, no more than 45% by volume of the polymer component, or no more than 40% by volume of the polymer component, all based on the total volume of the TIM. The TIM can comprise a range of polymer components from 8% to 70% by volume based on the total volume of the TIM, such as 20% to 50% by volume polymer components, 30% to 50% by volume polymer components, 30% to 60% by volume polymer components, 40% to 60% by volume polymer components, or 40% to 70% by volume polymer components, all based on the total volume of the TIM.

[0017] The polymeric component may be a thermosetting polymer. As used herein, the term "thermosetting" refers to a polymer that is irreversibly "cured" upon curing or crosslinking, where the polymer chains of the polymeric component are joined together by covalent bonds, which 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 will not melt upon application of heat and may be insoluble in conventional solvents. In certain embodiments, the polymer may be elastomeric (e.g., rubbery, soft, stretchy).

[0018] The polymer component may include a first polymer and at least one of a second polymer, a third polymer, and a fourth polymer. In various examples, the polymer component includes a first polymer, a second polymer, a third polymer, and a fourth polymer. The first polymer may include, for example, a vinyl-terminated polydimethylsiloxane, such as a divinyl-terminated polydimethylsiloxane (e.g., CAS number 68083-19-2). The first polymer may include a molecular weight of less than 30,000 g / mol, such as, for example, 26,000 g / mol or less, or 20,000 g / mol or less. The first polymer may include a functionality of at least 3. The polymer component may include at least 5 wt% of the first polymer, based on the total weight of the polymer component, for example, at least 10 wt%, at least 20 wt%, at least 30 wt%, at least 40 wt%, or at least 50 wt% of the first polymer, based on the total weight of all the polymer components. The polymeric component can comprise 99% or less by weight of the first polymer, such as 95% or less, 90% or less, 80% or less, 75% or less, or 70% or less by weight of the first polymer, based on the total weight of all the polymeric components. For example, the polymeric component can comprise in the range of 5% to 99% by weight of the first polymer component, based on the total weight of the polymeric components, such as 5% to 90% by weight, 20% to 80% by weight, or 40% to 75% by weight of the first polymer component, based on the total weight of all the polymeric components.

[0019] The molecular weight of the polymer may be determined according to ASTM D4001-20.

[0020] The second polymer can include, for example, a vinyl-terminated polydimethysiloxane, such as a divinyl-terminated polydimethylsiloxane (e.g., CAS number 68083-19-2). The second polymer can include a molecular weight of at least 30,000 g / mol, such as at least 40,000 g / mol, at least 50,000 g / mol, at least 60,000 g / mol, at least 70,000 g / mol, at least 80,000 g / mol, or at least 90,000 g / mol. The second polymer can include a molecular weight in a range of 30,000 g / mol to 500,000 g / mol, such as in a range of 40,000 g / mol to 400,000 g / mol, in a range of 50,000 g / mol to 200,000 g / mol, or in a range of 80,000 g / mol to 150,000 g / mol. The second polymer may be difunctional. The polymer component may comprise at least 5% by weight of the second polymer, such as at least 10% by weight, at least 20% by weight, at least 30% by weight, at least 40% by weight, or at least 50% by weight of the second polymer, based on the total weight of the polymer components. The polymer component may comprise no more than 95% by weight of the second polymer, such as no more than 95% by weight, no more than 90% by weight, no more than 75% by weight, no more than 50% by weight, no more than 40% by weight, no more than 30% by weight, or no more than 25% by weight of the second polymer, based on the total weight of the polymer components. For example, the polymer component may comprise a range of 5% to 95% by weight of the second polymer, such as a range of 5% to 90% by weight, 5% to 50% by weight, 5% to 25% by weight, or 10% to 25% by weight of the second polymer, based on the total weight of the polymer components.

[0021] The third polymer can include, for example, an alkyl-terminated polydimethylsiloxane, such as dialkyl-terminated polydimethylsiloxane (e.g., CAS number 63148-62-9). The molecular weight of the third polymer can be at least 30,000 g / mol, such as at least 40,000 g / mol, at least 50,000 g / mol, at least 60,000 g / mol, at least 70,000 g / mol, at least 80,000 g / mol, or at least 90,000 g / mol. The molecular weight of the third polymer can be in the range of 30,000 g / mol to 500,000 g / mol, such as in the range of 40,000 g / mol to 400,000 g / mol, in the range of 50,000 g / mol to 200,000 g / mol, or in the range of 80,000 g / mol to 150,000 g / mol. The polymeric component can include at least 1 wt% of a third polymer based on the total weight of the polymeric components, e.g., at least 2.5 wt%, at least 5 wt%, or at least 10 wt% of a third polymer based on the total weight of all the polymeric components. The polymeric component can include no more than 25 wt% of a third polymer based on the total weight of the polymeric components, e.g., no more than 20 wt%, no more than 15 wt%, no more than 10 wt%, or no more than 5 wt% of a third polymer based on the total weight of all the polymeric components. For example, the polymeric component can include a range of 1 wt% to 25 wt% of a third polymer based on the total weight of the polymeric components, e.g., a range of 1 wt% to 20 wt%, a range of 5 wt% to 20 wt%, a range of 5 wt% to 10 wt%, or a range of 1 wt% to 10 wt%, of a third polymer component based on the total weight of all the polymeric components.

[0022] The fourth polymer can include polybutadiene. The polymer component can include at least 5 wt% of the fourth polymer based on the total weight of the polymer components, such as at least 8 wt% of the fourth polymer, or at least 10 wt% of the fourth polymer, based on the total weight of all the polymer components. The polymer component can include 20 wt% or less of the fourth polymer based on the total weight of the polymer components, such as 15 wt% or less of the fourth polymer, or 12 wt% or less of the fourth polymer, based on the total weight of all the polymer components. The polymer component can include a range of 5 wt% to 20 wt% of the fourth polymer based on the total weight of the polymer components, such as a range of 8 wt% to 20 wt% or a range of 8 wt% to 15 wt% of the fourth polymer, based on the total weight of all the polymer components. The fourth polymer can react with the first polymer and / or form an emulsion with the first polymer. The fourth polymer can be added to the polymer component to maintain a desired viscosity of the polymer component.

[0023] The polymeric component can include a first polymer in the range of 5% to 99% by weight, a second polymer in the range of 5% to 95% by weight, a third polymer in the range of 1% to 25% by weight, and a fourth polymer in the range of 5% to 20% by weight, all based on the total weight of the polymeric component. In various embodiments, the polymeric component can include a first polymer in the range of 5% to 90% by weight, a second polymer in the range of 5% to 25% by weight, a third polymer in the range of 5% to 10% by weight, and a fourth polymer in the range of 5% to 20% by weight, all based on the total weight of the polymeric component. In certain embodiments, the polymeric component can include a first polymer in the range of 40% to 75% by weight, a second polymer in the range of 10% to 25% by weight, and a third polymer in the range of 1% to 10% by weight, all based on the total weight of the polymeric component.

[0024] The first polymer can be balanced with the second polymer and / or the third polymer in the polymer component to achieve a desired crosslink density in the cured polymer component. For example, increasing the amount of the second polymer and / or the third polymer relative to the first polymer can decrease the crosslink density in the cured polymer component. Thus, balancing the first polymer, the second polymer, and / or the third polymer can achieve a desired crosslink density while achieving the desired adhesive and stretch properties of the resulting polymer component.

[0025] In certain embodiments, the polymer component further comprises a silane coupling agent, such as, for example, vinylisopropyltriethoxysilane, based on the total weight of the polymer component. The polymer component can comprise in the range of 0.1% to 0.5% by weight of the silane coupling agent, based on the total weight of the polymer component. In various embodiments, the polymer component further comprises a catalyst.

[0026] The polymer component can include other additives, as desired. For example, the polymer component can also include a crosslinker, which can include, for example, an aminoplast, a polyisocyanate (including blocked isocyanates), a polyepoxide, a beta-hydroxyalkylamide, a polyacid, an anhydride, an organometallic acid functional material, a polyamine, a polyamide, or a combination thereof. The first, second, third, and / or fourth polymer can have functional groups that are reactive with the crosslinker.

[0027] The liquid metal for the TIM can include gallium, gallium alloy, indium, indium alloy, tin, tin alloy, mercury, mercury alloy, or combinations thereof. The liquid metal can be in a liquid phase at least at a temperature of at least -20 degrees Celsius (e.g., in its bulk form, can include a melting point below -20 degrees Celsius), such as 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 liquid metal can be in a liquid phase at a temperature of at least 30 degrees Celsius or less (e.g., in its bulk form, can include a melting point below 30 degrees Celsius), such as at least 25 degrees Celsius or less, at least 20 degrees Celsius, at least 15 degrees Celsius, at least 10 degrees Celsius, at least 5 degrees Celsius, at least 0 degrees Celsius, or at least -10 degrees Celsius. The liquid metal may be in a liquid phase at least at temperatures between -20 degrees Celsius and 30 degrees Celsius (e.g., in its bulk form, may include a melting point below a temperature in the range of -20 degrees Celsius to 30 degrees Celsius), such as between -19 degrees Celsius to 30 degrees Celsius, between -19 degrees Celsius to 25 degrees Celsius, or between -19 degrees Celsius to 20 degrees Celsius, etc. Determination of whether the liquid phase is achieved at each temperature may be performed at an absolute pressure of 1 atmosphere. In certain embodiments, the TIM may include a gallium indium tin alloy (e.g., GALINSTAN™, METSPEC 51™) and a melting point of -19 degrees Celsius.

[0028] The TIM can comprise at least 30% by volume of liquid metal droplets, based on the total volume of the TIM, e.g., at least 35% by volume, at least 40% by volume, at least 45% by volume, at least 50% by volume, at least 55% by volume, or at least 60% by volume, based on the total volume of all the liquid metal droplets. The TIM can comprise no more than 92% by volume of liquid metal droplets, based on the total volume of the TIM, e.g., no more than 90% by volume of liquid metal droplets, no more than 80% by volume of liquid metal droplets, no more than 75% by volume of liquid metal droplets, no more than 70% by volume of liquid metal droplets, no more than 65% by volume of liquid metal droplets, or no more than 60% by volume, based on the total volume of all the TIM. The TIM can comprise liquid metal droplets in the range of 30% to 80%, e.g., 40% to 75% liquid metal droplets, 45% to 75% liquid metal droplets, 45% to 70% liquid metal droplets, or 50% to 70% liquid metal droplets, by total volume of the TIM, all based on the total volume of the TIM.

[0029] In various embodiments, the TIM further comprises 0.1 to 0.5 wt % fumed silica, based on the total weight of the TIM. The fumed silica can enhance the stability of the uncured TIM during storage, preventing phase separation or settling of components in the uncured TIM.

[0030] The TIM, when cured, can include a strain limit of at least 100%, such as at least 200% or at least 300%, etc. The TIM, when cured, can include a strain limit of 600% or less, such as 500% or less or 400% or less, etc. For example, the TIM, when cured, can include a strain limit in the range of 100%-600%, such as 100%-500%.

[0031] The TIM may include a 10% Young's modulus of 3000 kPa or less when cured, such as 2000 kPa or less, 1500 kPa or less, or 800 kPa or less. For example, the TIM may include a Young's modulus in the range of 100 kPa to 3000 kPa, such as 500 kPa to 1500 kPa, or 600 kPa to 800 kPa, when cured. In various embodiments, the adhesive strength of the TIM may be greater than the cohesive strength of the TIM. The 10% Young's modulus can be used to estimate the softness of a material, since many polymers do not have linear stress-strain behavior. The softer the material, the less force can be introduced during warping of the assembly, and therefore the less likely the TIM will delaminate or break.

[0032] To measure the strain limit and 10% Young's modulus, a dog-bone shaped specimen is prepared with a TIM length of 50 mm, width of 10 mm, and thickness of 0.3-0.6 mm. The specimen is then clamped at the top and bottom using a Mark-10 mechanical tester. The actual free length of the specimen is then measured using a caliper. The specimen is stretched at a displacement rate of 10-50 mm / min until failure. During stretching, the strain at break is measured to determine the Young's modulus, and the length of the specimen at break is measured to determine the strain limit.

[0033] The TIM can be made by forming an emulsion of the polymer component and the liquid metal such that the liquid metal droplets are substantially dispersed throughout the polymer. For example, the polymer component and the liquid metal droplets can be mixed together in a high shear mixer, a centrifugal mixer, by shaking in a container, in a mortar and pestle, by sonication, or a combination thereof. Details regarding exemplary methods for forming the emulsion are described in (1) published PCT WO / 2019 / 136252, entitled "Method of Synthesizing a Thermally Conductive and Stretchable Polymer Composite," and (2) published U.S. Patent Application No. 2017 / 0218167, entitled "Polymer Composite with Liquid Phase Metal Inclusions," both of which are incorporated herein by reference in their entireties. The composition and / or mixing technique can be selected such that the viscosity of the TIM emulsion in the uncured state is 500,000 cP or less, such as 200,000 cP (centipoise) or less, 200,000 cP or less, 150,000 cP or less, 100,000 cP or less, 50,000 cP or less, 15,000 cP or less, 14,000 cp or less, 13,000 cP or less, 12,000 cP or less, 11,000 cP or less, or 10,000 cP or less. The viscosity of the TIM emulsion can be measured by a rotational viscometer or a cone and plate viscometer at room temperature. The viscosity measurement can be performed using a parallel plate rheometer (TA Instrument) at a selected frequency suitable for generating a static viscosity (e.g., because the material is a non-Newtonian fluid).

[0034] The composition and / or mixing technique can be selected to achieve a desired average particle size of the liquid metal droplets in the TIM. The average particle size of the liquid metal droplets 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 150 microns, etc. The average particle size of the liquid metal droplets can be 200 microns or less, such as 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, etc. For example, the average particle size of the liquid metal droplets can be in the range of 1 micron to 200 microns, such as 5 microns to 150 microns, 35 microns to 150 microns, 35 microns to 70 microns, or 5 microns to 100 microns.

[0035] As used herein, "average particle size" refers to the average size measured using microscopy (e.g., optical or electron microscopy). The size can be the diameter of a spherical particle, or the length along the largest dimension in the case of an ellipsoid or other irregularly shaped particle.

[0036] The polydispersity of the liquid metal droplets can be monomodal or multimodal (e.g., bimodal, trimodal). Multimodal polydispersity can be exploited to increase the packing density of the liquid metal droplets in the TIM. In certain embodiments where the polydispersity is monomodal, the polydispersity of the liquid metal droplets in the polymer can be in the range of 0.3 to 0.4.

[0037] The TIM can be stored in a container 100 prior to use, as illustrated in FIG. 1. For example, the container can include a wall 102 defining a cavity, and the TIM emulsion 104 can be stored in the cavity. The TIM 104 can be in an uncured state in the container 100. Storage of the TIM 104 in the container 100 can inhibit curing of the TIM 104. The container 100 can be a pillow pack, a syringe, a beaker, a jar, a bottle, a drum, or a combination thereof. In various examples, the container 100 can be a ready-to-use dispensing device, such as, for example, a pillow pack or a syringe. In other examples, the TIM 104 may not be stored and can be used after creation of the emulsion without storage.

[0038] As used herein, the terms "cure" and "curing" refer to the chemical cross-linking of components in an emulsion or material applied onto a substrate, or an increase in viscosity of components in an emulsion or material applied onto a substrate. Thus, the terms "cure" and "curing" do not encompass only the physical drying of an emulsion or material through solvent or carrier evaporation. In this regard, the term "cured" refers to the state of an emulsion or material where the components of the emulsion or material 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).

[0039] Curing of the thermosetting polymer can be achieved by applying a temperature to the TIM 104 of at least -20 degrees Celsius, such as at least 10 degrees Celsius, at least 50 degrees Celsius, at least 100 degrees Celsius, or at least 150 degrees Celsius. Curing can be achieved by applying a temperature to the TIM 104 of 300 degrees Celsius or less, such as 250 degrees Celsius or less, 200 degrees Celsius or less, 150 degrees Celsius or less, 100 degrees Celsius or less, or 50 degrees Celsius or less. Curing can be achieved by applying a temperature to the TIM 104 that is in the range of -10 degrees Celsius to 300 degrees Celsius, such as 10 degrees Celsius to 200 degrees Celsius, or 50 degrees Celsius to 150 degrees Celsius. For example, curing can include thermally baking the TIM. The temperature can be applied for a period of more than 1 minute, such as more than 5 minutes, more than 30 minutes, more than 1 hour, or more than 2 hours.

[0040] The TIM 104 may be dispensed from the container 100 and applied in an uncured state. The TIM 104 may then be cured to form a cured TIM 104. Curing the TIM 104 may include heating the TIM 104, adding a catalyst to the TIM 104, exposing the TIM 104 to air, applying pressure to the TIM 104, or a combination thereof. Curing the TIM 104 may increase the viscosity of the TIM emulsion to 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, or greater than 250,000 cP. For example, the polymer in the TIM 104 may be cured. In various examples, the TIM 104 may be an adhesive. The polymer in the TIM 104 may be selected to reduce outgassing of the TIM 104 during curing.

[0041] A TIM according to the present disclosure can be applied to a first layer such that the TIM is between two layers of an assembly including a first layer and a second layer. The first layer can be a heat generating electronic component (e.g., an integrated circuit) and the second layer can be a top layer that can be thermally conductive. For example, the top layer can be a heat spreader, a heat sink, or packaging. The assembly can then be compressed, thereby deforming the liquid metal droplets in the TIM, and the TIM can be cured to form the assembly. Applying the TIM 104 in an uncured state can achieve a desired contact resistance and allow lower pressures to be used when compressing the assembly. The TIM can be applied to various layers and devices, and is described below with reference to an integrated circuit assembly and with reference to Figures 2A-B, but is not limited to integrated circuit assemblies.

[0042] 2A, the TIM 204 can be applied to the integrated circuit die 206 of the integrated circuit 208 of the integrated circuit assembly 200 such that the TIM 204 is between and in contact with the integrated circuit die 206 and the top layer 210 of the integrated circuit assembly 200. Applying the TIM 204 to the integrated circuit die 206 can include spray coating, spin coating, dip coating, roll coating, flow coating, film coating, brush coating, extrusion, dispensing, or combinations thereof. The TIM 204 can be applied in an uncured state such that the TIM is conformable to the surfaces of the integrated circuit die 206 and the top layer 210 so that a desired level of surface contact can be achieved therebetween. In various examples, the TIM 204 can be applied directly to the integrated circuit die 206, and then the top layer 210 can be applied directly to the TIM 204. In various other examples, the TIM 204 can be applied directly to the top layer 210, and then the integrated circuit die 206 can be applied directly to the TIM 204. In various examples, after application of TIM 204, TIM 204 can be in direct contact with integrated circuit die 206 and top layer 210. In certain examples, application of TIM 204 can be limited to the surface of integrated circuit die 206 so that TIM 204 can be efficiently used.

[0043] As used herein, particularly in reference to a layer, film, or material, the terms "on," "onto," "over," and variations thereof (e.g., "applied on," "formed on," "deposited on," "provided on," "positioned on," etc.) mean applied, formed, deposited, provided, or otherwise positioned on the surface of a substrate, but not necessarily in contact with the substrate. For example, a TIM "applied" to a substrate does not preclude the presence of another or other layer of the same or different composition positioned between the applied TIM and the substrate. Similarly, a second layer "applied" to a first layer does not preclude the presence of another or other layer of the same or different composition positioned between the applied second layer and the applied TIM.

[0044] The integrated circuit assembly 200 can be compressed. For example, referring to the detailed views of FIGS. 3A-3B, the integrated circuit die 206 and the top layer 210 are compressed such that the first distance d1 is smaller than the second bond line distance d bl Prior to the application and / or compression process, the average particle size of the liquid metal droplets 312 in the TIM 204 may be reduced to a desired bond line distance d bl For example, the average particle size of the liquid metal droplets 312 before the application and / or compression process can be selected to be greater than, for example, the bond line distance d bl 1% larger than the bond line distance d bl 2% larger than the bond line distance d bl 5% larger than the bond line distance d bl 10% larger than the bond line distance d bl 15% larger than the bond line distance d bl 20% larger than the bond line distance d bl 30% larger than the bond line distance d bl 40% larger than the bond line distance d bl 50% greater than the bond line distance d bl 75% larger than the bond line distance d bl The average particle size of the liquid metal droplets 312 before the application and / or compression process can be greater than the bond line distance d bl 100% or less than the bond line distance d bl 75% or less larger than the bond line distance d bl 50% or less larger than the bond line distance d bl 40% or less larger than the bond line distance d bl 30% or less larger than the bond line distance d bl 20% or less larger than the bond line distance d bl 15% or less larger than the bond line distance d bl 10% or less larger than the bond line distance d bl or less than 5% larger than the bond line distance d blThe average particle size of the liquid metal droplets 312 before the application and / or compression process may be up to 2% greater than the bond line distance d bl 1% to 100% higher than the bond line distance d bl 1% to 50% larger than the bond line distance d bl 1% to 30% larger than the bond line distance d bl 2% to 30% larger than the bond line distance d bl The range may be 5% to 20% larger than the reference value.

[0045] Compressing the integrated circuit assembly 200 can apply a force to the TIM 204, deforming the liquid metal droplets 312 dispersed in the polymer component 314 of the TIM 204. Because the TIM 204 is in an uncured state, the polymer is still conformable and mobile such that the compressive force can deform the liquid metal droplets 312. The liquid metal droplets 312 can be in a liquid phase during deformation such that less pressure is needed for compression and the desired deformation is achieved.

[0046] The liquid metal droplets 312 can be generally spherical as shown in FIG. 3A and can then be generally ellipsoidal as shown in FIG. 3B. In various examples, the liquid metal droplets 312 before compression can have a first average aspect ratio, and after compression, the liquid metal droplets 312 can have a second average aspect ratio. The second average aspect ratio can be different from the first average aspect ratio. For example, the second average aspect ratio can be greater than the first average aspect ratio. The average aspect ratio can be an average ratio of the width of the liquid metal droplets 312 to the height of the liquid metal droplets 312. In various examples, the first aspect ratio can be 1 and the second aspect ratio can be greater than 1. In certain embodiments, the first aspect ratio can be in a range of 1 to 1.5. In certain embodiments, the second aspect ratio can be at least 0.5 greater than the first aspect ratio, e.g., 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. The width of the liquid metal droplet 312 can be substantially aligned with the longitudinal plane of the TIM 204 in the circuit assembly 200, and the height of the liquid metal droplet 312 can be substantially aligned with the thickness (e.g., distance, d1) of the TIM 204. The width of the liquid metal droplet 312 can increase upon compression of the circuit assembly 200. For example, in certain embodiments, the radius of a spherical liquid metal droplet before compression can be 100 μm (e.g., first aspect ratio of 1), and after compression to a bond line thickness of 20 μm, the liquid metal droplet can deform into an elliptical shape with a width of 316 μm (e.g., second aspect ratio of 15.6).

[0047] In one particular example, the liquid metal droplets 312 may be aligned in a substantially monolayer after compression, as shown in FIG. bl Arranging the liquid metal droplets 312 in a monolayer can reduce the thermal resistance of the TIM 204.

[0048] The TIM 204 can be cured, thereby forming the integrated circuit assembly 200. Curing the TIM 204 can increase the viscosity of the polymer component 314 and can harden the polymer component 314. For example, the polymer component 314 can become a solid. In various examples, the polymer component 314 after curing is an elastomer. Curing the polymer component 314 can inhibit pumping from the liquid metal droplet 312 during thermal cycling of the integrated circuit assembly 200 and can provide a mechanical bond (e.g., an adhesive bond) between the die 206 and the top layer 210.

[0049] The cured TIM 204 can provide desirable adhesion between the integrated circuit die 206 and the top layer 210. For example, the TIM 204 can include a lap shear strength of at least 1 MPa, such as at least 2 MPa, at least 3 MPa, at least 4 MPa, at least 5 MPa, or at least 6 MPa. In various examples, the TIM 204 can include a lap shear strength in the range of 1 MPa to 6 MPa. The lap shear can be measured according to ASTM D1002.

[0050] The integrated circuit assembly 200 has a bond line distance d formed between the die 206 and the top layer 210 in the cured assembly that is 150 microns or less, e.g., 145 microns or less, 140 microns or less, 120 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 assembly 200 can include a bond line distance d formed between the die 206 and the top layer 210 in the cured assembly that is at least 15 microns, such as at least 30 microns, at least 35 microns, at least 40 microns, at least 50 microns, at least 70 microns, at least 80 microns, at least 100 microns, at least 120 microns, at least 140 microns, or at least 145 microns. blThe assembly 200 may include a bond line distance d formed between the die 206 and the top layer 210 in the cured assembly that is in the range of 15 microns to 150 microns, such as in the range of 15 microns to 90 microns, in the range of 15 microns to 70 microns, in the range of 30 microns to 70 microns, in the range of 35 microns to 70 microns, or in the range of 15 microns to 100 microns. bl may include.

[0051] The hardening may occur over a first period of time and the compression may occur over a second period of time. The first period of time may be after the second period of time or may at least partially overlap with the second period of time. For example, the liquid metal droplets 312 may be deformed prior to substantial hardening of the polymer component 314 such that a lower compression pressure may be used to deform the liquid metal droplets 312.

[0052] The average particle size and deformation of the liquid droplets 312 can improve the thermal resistance of the TIM 204. For example, the TIM 204 after curing has a thermal resistance of 30(°K*mm 2 ) / W or less, e.g., 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 2 After curing, the TIM 204 may include a thermal resistance of at least 0.5(°K*mm) / W or less. 2 ) / W, e.g., 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 After curing, TIM204 has a thermal resistance of 0.5(°K*mm) / W. 2 ) / W~30(°K*mm 2) / W, e.g., 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 ) / W, etc. Thermal resistance values ​​can be measured using a DynTIM-S instrument available from Siemens (Munich, Germany), a TIMA instrument manufactured by NanoTest (Germany), and / or a LongWin LW 9389 (Taiwan).

[0053] The integrated circuit die 206 may comprise an integrated circuit such as, for example, a processor, or an ASIC, or a system on a chip (SOC). The top layer 210 may be an integrated heat spreader. The TIM 204 may be applied directly between the processor and the integrated heat spreader. For example, the TIM 204 may be TIM1, TIM1.5, or a combination thereof. TIM1 may be used to thermally connect the integrated circuit die and the integrated heat spreader in a lidded package. TIM1.5 may be used to thermally connect the integrated circuit die to a heat sink in a bare die package.

[0054] 2B, a TIM 216 can be applied between the top layer 210 (e.g., an integrated heat spreader) and a different top layer 218. The top layer 218 can comprise a heat sink. For example, the TIM 216 can be TIM2.

[0055] In various other examples, a TIM according to the present disclosure can be used in a system on a 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 can contact a top layer or layers on different sides.

[0056] <Example>

[0057] The present disclosure will be more fully understood by reference to the following examples, which provide illustrative, non-limiting aspects of the invention. It should be understood that the invention described herein is not necessarily limited to the examples described in this section.

[0058] A comparative TIM, a first inventive TIM, a second inventive TIM, and a third inventive TIM were prepared with a polymer and liquid metal droplets. Each TIM had a volume percent of liquid metal droplets. The liquid metal droplets included a gallium indium tin alloy. The comparative TIM included a polymer component including 100 weight percent vinyl terminated polydimethylsiloxane having a molecular weight of 30,000 g / mol or less and 10 parts per hundredth (PHR) of associated catalyst. The first inventive TIM comprised 60 wt. % vinyl terminated polydimethylsiloxane having a molecular weight of 30,000 g / mol or less and 10 PHR of associated catalyst, 20 wt. % vinyl terminated polydimethylsiloxane having a molecular weight of 92,000 g / mol, 10 wt. % alkyl terminated polydimethylsiloxane having a molecular weight of 308,000 g / mol, 10 wt. % polybutadiene, and 0.5 wt. % silane coupling agent, all based on the total weight of the polymer components. The second inventive TIM comprised 65 wt. % vinyl terminated polydimethylsiloxane having a molecular weight of 30,000 g / mol or less and 10 PHR of associated catalyst, 10 wt. % vinyl terminated polydimethylsiloxane having a molecular weight of 92,000 g / mol, 5 wt. % alkyl terminated polydimethylsiloxane having a molecular weight of 308,000 g / mol, 20 wt. % polybutadiene, and 0.5 wt. % silane coupling agent, all based on the total weight of the polymer components. A third inventive TIM comprised 75 wt. % vinyl terminated polydimethylsiloxane having a molecular weight of 30,000 g / mol or less and 10 PHR of associated catalyst, 10 wt. % vinyl terminated polydimethylsiloxane having a molecular weight of 92,000 g / mol, 5 wt. % alkyl terminated polydimethylsiloxane having a molecular weight of 308,000 g / mol, 10 wt. % polybutadiene, and 0.5 wt. % silane coupling agent, all based on the total weight of the polymer components.

[0059] Each TIM was cured and subjected to a 180 degree peel test, which is a modified version of ASTM D1876-01. During the 180 degree peel test, a strip of the sample having a width of 10 mm and a thickness of 500 um is adhered to the substrate by forming a film on the substrate and curing in an oven to harden the polymer. The TIM is then peeled from the substrate at an angle of 180°. The comparative TIM was determined to have a peel force of nearly zero, with the entire TIM peeling off as a single piece. The first inventive TIM, the second inventive TIM, and the third inventive TIM exhibited peel strengths in the range of 20-50 N / m indicating that greater adhesion was achieved. In addition, high adhesion was observed for the first, second, and third inventive TIMs compared to the cohesion of the sample, thereby resulting in the fracture of the sample upon connection to the substrate.

[0060] In addition, the strain limit of each of the cured TIMs was tested: the comparative TIM exhibited an average strain limit of 77%, the first inventive TIM exhibited an average strain limit of 155%, the second inventive TIM exhibited an average strain limit of 119%, and the third inventive TIM exhibited an average strain limit of 131.5%.

[0061] Those skilled in the art will recognize that the compositions, articles, methods, and accompanying discussion described herein are used as examples for conceptual clarity, and that various configuration modifications are contemplated. As a result, as used herein, the specific examples described and the accompanying discussion are intended to be representative of their more general classes. In general, the use of any specific example is intended to represent that class, and the non-inclusion of specific components (e.g., operations), devices, and objects should not be considered limiting.

[0062] With respect to the appended claims, those skilled in the art will understand that the operations recited therein may generally be performed in any order. Also, while various operational flows are presented in a sequence, it should be understood that various operations may be performed in orders other than those illustrated or may be performed simultaneously. Examples of such alternative orderings may include overlapping, interleaving, interrupting, reordering, incrementing, preparing, complementing, simultaneous, reverse, or other variable orderings, unless the context dictates otherwise. Moreover, terms such as "responsive to," "related to," or other past tense adjectives are generally not intended to exclude such variations, unless the context dictates otherwise.

[0063] While various examples have been described herein, many modifications, variations, substitutions, changes, and equivalents to those examples may be implemented and will occur to those skilled in the art. Also, where materials are disclosed for a particular component, other materials may be used. It is therefore to be understood that the foregoing description and the appended claims are intended to cover all such modifications and variations as are within the scope of the disclosed embodiments. The following claims are intended to cover all such modifications and variations.

[0064] Various features and characteristics are described herein to provide an understanding of the compositions, structures, manufacture, function, and / or operation of the invention, including the disclosed compositions, coatings, and methods. It is to be understood that the various features and characteristics of the invention described herein may be combined in any suitable manner, regardless of whether such features and characteristics are expressly described in combination herein. The inventors and applicants expressly intend that such combinations of features and characteristics are included within the scope of the invention described herein. Thus, the claims may be amended to recite any features and characteristics that are expressly or inherently described herein or otherwise expressly or inherently supported by the present specification, in any combination. Furthermore, the applicants reserve the right to amend the claims to affirmatively deny features and characteristics that may exist in the prior art, even if those features and characteristics are not expressly described herein. Thus, any such amendments do not add new matter to the specification or claims, but are subject to the requirements of written description, sufficiency of description, and added matter.

[0065] Any numerical range recited herein describes all subranges of the same numerical precision (i.e., having the same number of specified digits) contained within the recited range. For example, a recited range of "1.0 to 10.0" describes all subranges from the recited minimum value of 1.0 to the recited maximum value of 10.0 (including their upper and lower limits), such as "2.4 to 7.6," even if the range "2.4 to 7.6" is not explicitly recited within the text of this specification. Accordingly, applicants reserve the right to amend this specification, including the claims, to explicitly recite any subrange of the same numerical precision contained within the ranges explicitly recited herein. All such ranges are inherently described herein, and therefore any amendment to explicitly recite any such subranges will comply with the requirements of written description, sufficiency of description, and added matter.

[0066] Moreover, unless expressly specified or otherwise required by context, all numerical parameters described herein (such as those expressing values, ranges, amounts, percentages, etc.) can be read as if preceded by the word "about", even if the word "about" does not explicitly appear before the numerical value. In addition, the numerical parameters described herein should be construed by applying the reported number of significant digits, numerical precision and ordinary rounding techniques. It should also be understood that the numerical parameters described herein necessarily have the inherent variability characteristic of the underlying measurement techniques used to determine the numerical value of the parameters.

[0067] 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, however, any numerical value inherently contains certain errors necessarily resulting from the standard variation found in their respective testing measurements.

[0068] References throughout this specification to "various examples," "several examples," "an example," "an example," or the like mean that a particular feature, structure, or characteristic described in connection with the example is included in the example. Thus, the appearances of phrases such as "various examples," "in some examples," "in one example," "in an example," and the like in certain locations 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, a particular feature, structure, or characteristic illustrated or described in connection with one example may be combined, in whole or in part, with a feature, structure, or characteristic of another example or other examples, without limitation. Such modifications and variations are intended to be included within the scope of the present embodiments.

[0069] Any patent, publication, or other document identified herein is incorporated herein by reference in its entirety, unless otherwise indicated, to the extent that the incorporated material does not conflict with existing descriptions, definitions, descriptions, illustrations, or other disclosure material expressly set forth herein. Thus, to the extent necessary, the express disclosure set forth herein supersedes any conflicting material incorporated by reference. Any material, or portion thereof, that is incorporated herein by reference but conflicts with existing definitions, descriptions, or other disclosure material set forth herein is incorporated only to the extent that no conflict arises between the incorporated material and the existing disclosure material. Applicant reserves the right to amend this specification to explicitly recite any subject matter, or portion thereof, that is 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 added subject matter.

[0070] Although particular examples of the invention have been described above for purposes of illustration, it will be apparent to those skilled in the art that many variations in the details of the invention can be made without departing from the invention as defined in the appended claims.

[0071] While this disclosure provides descriptions of various specific embodiments for purposes of illustrating various aspects of the disclosure and / or its potential applications, it should be understood that variations and modifications will occur to those skilled in the art. Accordingly, the invention or inventions described herein should be understood to be at least as broad as they are claimed, and not to be more narrowly defined by the specific illustrative embodiments provided herein.

[0072] It should be understood that the invention described herein is not limited to the embodiments summarized in the Summary or Detailed Description. Various other embodiments are described and illustrated herein.

Claims

1. 1. An integrated circuit assembly comprising: an integrated circuit die; The upper layer and a thermal interface material disposed in contact with the integrated circuit die and the upper layer, the thermal interface material being between the integrated circuit die and the upper layer, the thermal interface material comprising: 8% to 70% by volume of a polymer component, based on the total volume of the thermal interface material; 5% to 99% by weight, based on the total weight of the polymer component, of a first polymer comprising vinyl-terminated polydimethylsiloxane, the first polymer having a molecular weight of less than 30,000 g / mol; 5% to 95% by weight, based on the total weight of the polymeric component, of a second polymer comprising vinyl-terminated polydimethylsiloxane, the second polymer having a molecular weight of at least 30,000 g / mol; 1% to 25% by weight, based on the total weight of the polymer component, of a third polymer comprising alkyl-terminated polydimethylsiloxane, the third polymer having a molecular weight of at least 30,000 g / mol; and 5% to 20% by weight, based on the total weight of the polymer component, of a fourth polymer comprising polybutadiene; and at least 30% by volume of liquid metal droplets, based on the total volume of the thermal interface material, dispersed throughout the polymer component; An integrated circuit assembly, wherein the thermal interface material, when cured, has a strain limit of at least 100% and the assembly has a lap shear strength of at least 1 MPa.

2. The polymer component is 5% to 85% by weight of the first polymer, based on the total weight of the polymer component; 5% to 25% by weight of the second polymer, based on the total weight of the polymer component; 5% to 10% by weight of the third polymer, based on the total weight of the polymer component; and 5% to 20% by weight, based on the total weight of the polymeric components, of a fourth polymer comprising polybutadiene.

3. The polymer component is 40% to 75% by weight of the first polymer, based on the total weight of the polymer component; 10% to 25% by weight of the second polymer, based on the total weight of the polymer component; 1% to 10% by weight of the third polymer, based on the total weight of the polymer component; and 5% to 20% by weight, based on the total weight of the polymeric components, of a fourth polymer comprising polybutadiene.

4. 10. The assembly of claim 1, wherein the first polymer has a functionality of at least three and the second polymer is difunctional.

5. The assembly of claim 1 , wherein the polymer component further comprises 0.1% to 0.5% by weight of a silane coupling agent, based on the total weight of the polymer component.

6. The assembly of claim 1 , wherein the thermal interface material further comprises 0.1 to 0.5 weight percent fumed silica.

7. The assembly of claim 1 , wherein the polymer component further comprises a catalyst.

8. The assembly of claim 1 , wherein the second polymer comprises divinyl-terminated polydimethylsiloxane.

9. The assembly of claim 1 , wherein the third polymer comprises a dialkyl-terminated polydimethylsiloxane.

10. The assembly of claim 1 , wherein the liquid metal droplets comprise gallium, a gallium alloy, indium, an indium alloy, tin, a tin alloy, mercury, a mercury alloy, or a combination thereof.

11. The assembly of claim 1 , wherein the liquid metal droplets are in a liquid phase at temperatures at least within the range of −19 degrees Celsius to 30 degrees Celsius.

12. The assembly of claim 1 , wherein the liquid metal droplet is generally ellipsoidal.

13. 10. The assembly of claim 1, wherein a bond line distance formed between the die and the top layer in the assembly is 150 microns or less.

14. The assembly of claim 1 , wherein the die comprises a processor and the top layer comprises a heat sink, an integrated heat spreader, or packaging.

15. The assembly of claim 1 , wherein the thermal interface material has a 10% Young's modulus of 3000 kPa or less.

16. 1. A method comprising: applying a thermal interface material onto an integrated circuit die of an integrated circuit assembly such that the thermal interface material is between the integrated circuit die and a top layer of the integrated circuit assembly, the thermal interface material applied to the integrated circuit die comprising: 8% to 70% by volume of a polymer component, based on the total weight of the thermal interface material; 5% to 99% by weight, based on the total weight of the polymer component, of a first polymer comprising vinyl-terminated polydimethylsiloxane, the first polymer having a molecular weight of less than 30,000 g / mol; 5% to 95% by weight, based on the total weight of the polymeric component, of a second polymer comprising vinyl-terminated polydimethylsiloxane, the second polymer having a molecular weight of at least 30,000 g / mol; 1% to 25% by weight, based on the total weight of the polymer component, of a third polymer comprising alkyl-terminated polydimethylsiloxane, the third polymer having a molecular weight of at least 30,000 g / mol; and 5% to 20% by weight, based on the total weight of the polymer component, of a fourth polymer comprising polybutadiene; and at least 30% by volume of liquid metal droplets, based on the total weight of the thermal interface material, dispersed throughout the polymer component; applying the thermal interface material, when cured, having a strain limit of at least 100%; compressing the integrated circuit assembly, thereby deforming the liquid metal droplets, wherein an average size of the liquid metal droplets in the thermal interface material prior to application is greater than a bond line distance formed between the die and the top layer in a cured assembly formed therefrom; and curing the thermal interface material to thereby form the cured assembly, wherein the thermal interface material has a lap shear of at least 1 MPa.

17. The polymer component is 5% to 90% by weight of the first polymer, based on the total weight of the polymer component; 5% to 25% by weight of the second polymer, based on the total weight of the polymer component; 5% to 10% by weight of the third polymer, based on the total weight of the polymer component; and 5% to 20% by weight, based on the total weight of the polymer component, of a fourth polymer comprising polybutadiene.

18. The polymer component is 40% to 75% by weight of the first polymer, based on the total weight of the polymer component; 10% to 25% by weight of the second polymer, based on the total weight of the polymer component; 1% to 10% by weight of the third polymer, based on the total weight of the polymer component; and 5% to 20% by weight, based on the total weight of the polymer component, of a fourth polymer comprising polybutadiene.

19. 17. The method of claim 16, wherein the first polymer has a functionality of at least three and the second polymer is difunctional.

20. 17. The method of claim 16, wherein the polymer component further comprises 0.1 wt % to 0.5 wt % of a silane coupling agent, based on the total weight of the polymer component.

21. The method of claim 16, wherein the thermal interface material further comprises 0.1 to 0.5 wt. % fumed silica.

22. The method of claim 16 , wherein the polymer component further comprises a catalyst.

23. 17. The method of claim 16, wherein the second polymer comprises divinyl-terminated polydimethylsiloxane.

24. The method of claim 16 , wherein the third polymer comprises a dialkyl-terminated polydimethylsiloxane.

25. 17. The method of claim 16, wherein the liquid metal droplets comprise gallium, a gallium alloy, indium, an indium alloy, tin, a tin alloy, mercury, a mercury alloy, or a combination thereof.

26. 17. The method of claim 16, wherein the liquid metal droplets are in the liquid phase at temperatures in the range of at least -19 degrees Celsius to 30 degrees Celsius.

27. The method of claim 16 , wherein the liquid metal droplet is generally ellipsoidal.

28. 17. The method of claim 16, wherein a bond line distance formed between the die and the top layer in the assembly is 150 microns or less.

29. 17. The method of claim 16, wherein the die comprises a processor and the top layer comprises a heat sink, an integrated heat spreader, or packaging.

30. 17. The method of claim 16, wherein the thermal interface material has a 10% Young's modulus of 3000 kPa or less.

31. 17. An integrated circuit assembly produced by the method of claim 16.

32. 1. A thermal interface material comprising: 8% to 70% by volume of a polymer component, based on the total volume of the thermal interface material; 5% to 99% by weight, based on the total weight of the polymer component, of a first polymer comprising vinyl-terminated polydimethylsiloxane, the first polymer having a molecular weight of less than 30,000 g / mol; 5% to 95% by weight, based on the total weight of the polymeric component, of a second polymer comprising vinyl-terminated polydimethylsiloxane, the second polymer having a molecular weight of at least 30,000 g / mol; 1% to 25% by weight, based on the total weight of the polymer component, of a third polymer comprising alkyl-terminated polydimethylsiloxane, the third polymer having a molecular weight of at least 30,000 g / mol; and 5% to 20% by weight, based on the total weight of the polymer component, of a fourth polymer comprising polybutadiene; and at least 30% by volume of liquid metal droplets, based on the total volume of the thermal interface material, dispersed throughout the polymer component; The thermal interface material, when cured, has a strain limit of at least 100% and the assembly has a lap shear strength of at least 1 MPa.

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