Rheology-controlled metal amalgams by incorporating non-heat-resistant filler particles

Abstract

A thermal interface material comprising a metal amalgam with non-heat-resistant particles.

Description

The complete disclosure of this provisional patent application is hereby incorporated by reference.REGIONThe present disclosure generally relates to rheologically controllable use of metal amalgams through the inclusion of non-refractory filler particles (e.g., non-refractory filler particles, etc.) to improve processing and reliability as thermal interface materials (TIMs), etc.BACKGROUNDThis section contains background information on the present disclosure that is not necessarily prior art.Electrical components, such as semiconductors, integrated circuits, transistors, etc., typically have fixed temperatures at which the electrical components operate optimally. Ideally, these specified temperatures correspond to the ambient temperature. However, the operation of the electrical components generates heat. If this heat is not dissipated, the electrical components can be operated at temperatures that are well above their normal or desired operating temperature. Such excessive temperatures may impair the operating characteristics of the electrical components and the operation of the associated electronic device.In order to avoid or at least reduce the negative operating properties caused by the heat development, the heat should be dissipated, for example by dissipation of the heat from the operated electrical component to a heat sink. The heat sink may then be cooled by conventional convection and / or radiation techniques. During the dissipation, the heat can pass from the operated electrical component to the heat sink, either by direct surface contact between the electrical component and the heat sink and / or by contact of the surfaces of the electrical component and the heat sink via an intermediate medium or a thermal interface material. The thermal interface material may be used to fill the gap between the heat transfer surfaces, thus increasing heat transfer efficiency as compared to filling with air, a relatively poor thermal conductor.DRAWINGSThe drawings described herein are for illustrative purposes only of selected embodiments and do not represent all possible implementations. They are not intended to limit the scope of the present disclosure.FIGS. 1 and 2 show comparisons between a conventional unfilled liquid metal without nickel and copper filler and a filled liquid metal (FLM) according to the example embodiments disclosed herein. Compared to the conventional unfilled liquid metal without nickel and copper filler, the filled liquid metal (FLM) after filling or loading had (e.g., about 1 wt % to about 10 wt %, etc.) Nickel and copper exhibit improved or increased viscosity, comparable thermal behavior, and improved propagation control (isotropic) (e.g., limited, reduced, or no material migration, etc.) when pressed between two substrates or plates. As shown in FIG. 2, no venting / pumping, rumbleing, rumming of the filled liquid metal (FLM) occurred during thermal reliability testing, e.g., thermal shock vertical reliability testing from -40° C. to 150° C. for 1,000 cycles, as shown in FIG. 2, etc. This provides a significant benefit in liquid metal processing and keeps the material in place (e.g., without the material migrating, leaking, pumping, or creep, etc.) during use in an electronic device.DETAILED DESCRIPTIONEmbodiments will now be described in more detail with reference to the accompanying drawings.As mentioned previously, conventional rheologically controlled liquid metal systems lose thermal performance because the rheological and spreading properties are controlled. For example, conventional rheologically controlled materials include liquid metals having silicone and / or polymer components that limit the thermal conductivity and thermal resistance of the material. Conventional liquid metal distributes unevenly (anisotropically) when pressed between two substrates or plates (e.g., glass, etc.), as shown in FIG. 1, leading to problems in processing the material into components for use as a thermal interface material. Conventional liquid metal spreads during thermal reliability testing (also known as creep, exhaust, or motion) as shown in FIG. 2.Having recognized the above-noted disadvantages of conventional rheology controlled liquid metal systems, exemplary embodiments for controlling the rheology of metal amalgams (e.g., liquid metals, low melting alloys, gallium-based liquid metal alloys, etc.) have been developed and / or disclosed herein by inclusion, incorporation, or use of non-refractory metal fillers (e.g., nickel and copper, etc.). The addition of non-heat-resistant fillers (nickel and copper) increases the viscosity of the metal amalgam without impairing its thermal performance. The metal fillers remain suspended in the metal amalgam.In example embodiments, a thermal interface material (TIM) includes non-refractory (non-corrosion resistant) metal fillers incorporated into a metal amalgam (e.g., liquid metal, low melting alloy, etc.) to form a stable metal amalgam suspension with viscosity control based on the total loading of filler without compromising thermal performance for a TIM application. In such example embodiments, during thermal reliability tests, e.g., vertical reliability tests with thermal shock from -40° C. to 150° C. for 1000 cycles, as shown in FIG. 2, etc., the metal amalgam remains in place (e.g., without migrating, exiting, pumping out, or creep out, etc.). And the metal amalgam can be processed in a controlled manner on a substrate thanks to the rheology control that allows isotropic spreading of the material when pressing between two substrates or plates, as shown in FIG. 1, etc. The isotropic spreading control (e.g. limited, reduced or no material migration, etc.) occurs when the TIM is pressed between two substrates or plates, which is a processing advantage in the TIM range, as the materials are sandwiched in use and the surface coverage of the TIM is important. Conventional liquid metal which anisotropically spreads makes processing difficult.In example embodiments, a metal alloy (e.g., a low viscosity gallium indium tin liquid metal alloy, etc.) is filled with non-refractory metals such as copper and nickel particles. This enables a stable, homogeneous amalgam suspension. This leads to an increase in viscosity, rheology control based on the total loading of filler, robust wetting of various surfaces, and controlled spreading in processing and reliability. Although these properties are improved, the thermal performance of the material remains unchanged after the copper and nickel particles are mixed into the metal alloy. The material may have a glossy, lustrous, silver compound with a puddle-like consistency.FIGS. 1 and 2 show comparisons between a conventional unfilled liquid metal without nickel and copper filler and a filled liquid metal (FLM) according to the example embodiments disclosed herein. Compared to the conventional unfilled liquid metal without nickel and copper filler, the filled liquid metal (FLM) after filling or loading had (e.g., about 1 wt % to about 10 wt %, etc.) Nickel and copper exhibit improved or increased viscosity, comparable thermal behavior, and improved propagation control (isotropic) (e.g., limited, reduced, or no material migration, etc.) when pressed between two substrates or plates. As shown in FIG. 2, no venting / pumping, rumbleing, rumming of the filled liquid metal (FLM) occurred during thermal reliability testing, e.g., thermal shock vertical reliability testing from -40° C. to 150° C. for 1,000 cycles, as shown in FIG. 2, etc. This provides a significant benefit in liquid metal processing and keeps the material in place (e.g., without the material migrating, leaking, pumping, or creep, etc.) during use in an electronic device.It has been observed that a metal amalgam (e.g., liquid metal, low melting point alloy, gallium indium tin liquid metal alloy, etc.) after filling or loading has been observed to be about 1 wt % to about 10 wt % (e.g., about 6 wt %, etc.) Nickel and copper had an increased viscosity. For example, for the conventional unfilled liquid metal alloy without nickel and copper filler, a low viscosity liquid consistency was observed. In comparison, a puddle-like consistency was observed for a metal amalgam with about 6 weight percent (wt %) nickel and copper.It has also been observed that a metal amalgam (e.g., liquid metal, low melting point alloy, gallium indium tin liquid metal alloy, etc.) after filling or loading has been observed to be from about 1 wt % to about 10 wt % (e.g., about 6 wt %, etc.) Nickel and copper maintained a comparable thermal performance (e.g., above 15 W / mK, etc.) as the conventional unfilled liquid metal alloy without nickel and copper filler. For example, a metal amalgam having about 6 weight percent (wt %) nickel and copper was observed to have a thermal conductivity in the range of 28 W / mK to 30 W / mK.As shown in FIG. 1, a filled liquid metal after filling or loading with nickel and copper (e.g., about 1 wt % to about 10 wt %, etc.) was found to have improved spread control (isotropic) (e.g., limited, reduced, or no material migration, etc.) when pressed between two substrates or plates (e.g., glass, etc.). In comparison, the conventional unfilled liquid metal without nickel and copper filler spread unevenly (anisotropically) when pressed between two substrates or sheets, as also shown in Figure 1.As shown in FIG. 2, it has been observed that the filled liquid metal is charged or filled with (e.g., about 1 wt % to about 10 wt %, etc.) Nickel and copper did not exit / pump out / crack out / migrate during thermal cycles, e.g., during a vertical thermal shock reliability test from -40° C. to 150° C. over 1000 cycles, etc. In comparison, the conventional unfilled liquid metal without nickel and copper filler has leaked, pumped out, crouched out, migrated on thermal cycles, as also shown in Figure 2.In example embodiments, a metal amalgam (e.g., liquid metal, low melting alloy, etc.) includes Nickel and copper such that the ratio of nickel to copper in weight percent (wt %) is in the range of about 1:1 to about 5:1. For example, in exemplary embodiments, a nickel-copper ratio of about 2:1 may be maintained, thereby achieving a stable, homogeneous metal amalgam suspension. In example embodiments, the metal amalgam is loaded with nickel and copper such that the total loading range of nickel and copper is between about 1 wt % and about 10 wt % (e.g., 4 wt %, 6 wt %, 8 wt %, etc.). In such exemplary embodiments, the filled metal amalgam may have a thermal conductivity of greater than 15 W / mK (e.g., 28 W / mK to 30 W / mK, etc.), a thermal resistance of less than about 4 mm 2 K / W but not less than about 1 mm 2 K / W, and a viscosity of at most 2800 pascal seconds at a shear rate of 0.5 / s and at most 75 pascal seconds at a shear rate of 5 / s.By way of example, an embodiment of a filled metal amalgam comprising a gallium indium tin liquid metal alloy filled with about 6 weight percent (wt %) nickel and copper may be mentioned. In this example, the filled metal amalgam had a thermal conductivity in the range of about 28 W / mK to about 30 W / mK, a contact thermal resistance of less than about 4 mm 2 K / W, a viscosity strain rate (in air) of 5 / s in the range of about 28 to about 33 pascal seconds, and a viscosity strain rate (in air) of 0.5 / s of about 407 pascal seconds. Consistency comparison showed that the filled metal amalgam had a puddle-like appearance. The specific alloy, 6 wt % loading, thermal conductivity, thermal resistance, and viscosity recited in this paragraph and elsewhere are merely examples as other example embodiments may be configured differently, e.g., other metal alloys (e.g., another low melting point alloy having a melting point of 160° C. or less, etc.), other liquid metal, higher or lower wt % loading, higher or lower thermal conductivity, higher or lower thermal resistance, and / or higher or lower viscosity, etc.For example only, another example embodiment of a filled metal amalgam comprises a gallium indium tin liquid metal alloy filled or loaded with about 8 weight percent (wt %) nickel and copper. In this example, the filled metal amalgam had a thermal conductivity in the range of about 28 W / mK to about 30 W / mK, a contact thermal resistance of less than about 4 mm 2 K / W, a viscosity strain rate (in air) of 5 / s in the range of about 60 to about 65 pascal seconds, and a viscosity strain rate (in air) of 0.5 / s of about 1997 pascal seconds. A consistency comparison showed that the filled metal amalgam had the consistency of a spreadable paste. The specific alloys recited in this paragraph and elsewhere, 8 wt % loading, thermal conductivity, thermal resistance, and viscosity are merely examples, other example embodiments may be configured differently, e.g., with other metal alloys (e.g., another low melting point alloy having a melting point of 160° C. or less, etc.), other liquid metal, higher or lower wt % loading, higher or lower thermal conductivity, higher or lower thermal resistance, and / or higher or lower viscosity, etc.As another example, another example embodiment of a filled metal amalgam comprises a gallium indium tin liquid metal alloy filled or loaded with about 10 weight percent (wt %) nickel and copper. In this example, the filled metal amalgam had a thermal conductivity in the range of about 28 W / mK to about 30 W / mK, a contact thermal resistance of less than about 4 mm 2 K / W, a viscosity strain rate (in air) of 5 / s in the range of about 60 to about 65 pascal seconds, and a viscosity strain rate (in air) of 0.5 / s of about 2595 pascal seconds. A consistency comparison showed that the filled metal amalgam had the consistency of a spreadable, thick paste. The specific alloys indicated in this paragraph and elsewhere, 10 wt % loading, thermal conductivity, thermal resistance, and viscosity are merely examples as other example embodiments may be configured differently, e.g., other metal alloys (e.g., another low melting point alloy having a melting point of 160° C. or less, etc.), other liquid metal, higher or lower wt % loading, higher or lower thermal conductivity, higher or lower thermal resistance, and / or higher or lower viscosity, etc.Compared to the three above examples with 6, 8, and 10 wt % nickel and copper loadings, a conventional unfilled liquid metal without nickel and copper filler (0 wt % filler loading in wt %) may have a thermal conductivity in the range of about 28 W / mK to about 30 W / mK, a contact thermal resistance of less than about 4 mm 2 K / W, a viscosity strain rate (in air) of 5 / s in the range of about 13 to about 16 pascal seconds, and a viscosity (in air) strain rate 0.5 / s of about 180 pascal seconds. A consistency comparison showed that the conventional unfilled liquid metal without nickel or copper filler had the consistency of a low viscosity liquid.As the above examples show, the final consistency of the metal amalgam loaded with non-refractory filler particles is based on the total loading of metal fillers. In exemplary embodiments, the nickel to copper ratio in weight percent (wt %) is in a range from about 1:1 to about 5:1. Although the consistency of the metal amalgam changes depending on the metal filler, the thermal performance remains the same, e.g., the thermal conductivity is above 15 W / mK (e.g., in a range from about 28 W / mK to about 30 W / mK, etc.), and the thermal resistance is below about 4 mm 2 K / W but not lower than about 1 mm 2 K / W.The above examples show a number of compositions in which an improved effect has been observed due to the non-heat resistant fillers (nickel and copper). However, these example compositions, while having increased viscosity and improved controlled spread (e.g., limited, reduced, or no material migration, etc.) when pressed between two substrates, do not alter the thermal properties. This is an advantage in practice because other rheology controlled systems with liquid metals lose thermal performance due to control of the rheology and spreading properties.The example embodiments disclosed herein may therefore provide one or more (but not necessarily all) of the following advantages. For example, other commercially available materials having rheology and spread control with liquid metal include silicone and / or polymer components that limit the thermal conductivity and thermal resistance of the material. In comparison, the exemplary embodiments disclosed herein do not allow for degradations in thermal conductivity and thermal resistance while maintaining rheology and spread control (e.g., by limiting or preventing material migration, etc.). The exemplary embodiments disclosed herein do not require solder mouldings or surface treatments to hold the material in place and / or wet the surface, as the non-refractory filler particle loaded metal amalgam (e.g., liquid metal, low melting alloy, etc.) loaded with non-refractory filler particles (e.g., non-refractory metal filler particles, etc.) may already wet surfaces. The exemplary embodiments disclosed herein do not include organic solvents and / or compounds that may reduce wetting and / or result in voids due to outgassing during thermal cycling. In all conventional liquid metal-filled metal amalgam systems, maintaining stable particle suspensions in the liquid metal is a central challenge. In the exemplary embodiments disclosed herein, the metal amalgam remains in a stable suspension after mixing the particles into the metal amalgam (e.g., liquid metal, low melting alloy, etc.). Traditionally, this stability is not achieved with non-refractory metals.Exemplary methods for rheologically controlled metal amalgamation by incorporating non-refractory filler particles (e.g., non-refractory metal filler particles, etc.) to improve processing and reliability as a thermal interface material are described. An example method may include rheologically controlled metal amalgamation with fill particles (e.g., non-refractory metal fill particles, etc.) for use as a thermal interface material without compromising thermal conductivity and maintaining rheology and spread control (e.g., limited, reduced, or no material migration, etc.) when pressing between two substrates. An example method may include using non-refractory (non-corrosion resistant) filler particles (e.g., non-refractory (non-corrosion resistant) metal filler particles, etc.) to obtain a stable, homogeneous metal amalgam suspension with viscosity control based on the total loading of filler particles without compromising thermal performance for applications as a thermal interface material. The rheology controlled metal amalgam can be used as a thermal interface material between a heat source and another component of an electronic device.In exemplary embodiments, the method includes rheologically controlling the metal amalgam including the non-refractory filler particles (e.g., non-refractory metal filler particles, etc.) so as to enable controlled processing of the metal amalgam including the non-refractory filler particles contained therein on a substrate, because the rheological control enables isotropic spreading of the liquid metal containing the non-refractory filler particles when pressed between two substrates.In exemplary embodiments, the method includes rheologically controlling the metal amalgam including the non-refractory filler particles (e.g., non-refractory metal filler particles, etc.) contained therein so as to ensure that the metal amalgam remains in place during the thermal reliability test (e.g., without the material migrating, bleeding, pumping, or leaking, etc.).In exemplary embodiments, the method comprises incorporating the non-refractory filler particles to thereby obtain a stable, homogeneous metal amalgam suspension that results in an increase in the viscosity of the metal amalgam.In exemplary embodiments, the method includes loading non-refractory filler particles to thereby achieve rheology control based on total loading of filler particles, robust wetting of various surfaces, and spread control (e.g., limiting or preventing material migration, etc.) in processing and reliability without sacrificing thermal performance after the non-refractory filler particles are mixed into the metal amalgam.In exemplary embodiments, the method includes loading a low viscosity gallium indium tin liquid metal alloy with copper and nickel particles to obtain a stable, homogeneous metal amalgam suspension that results in an increase in viscosity of the low viscosity gallium indium tin liquid metal alloy.In exemplary embodiments, the method includes loading a low viscosity gallium indium tin liquid metal alloy with copper and nickel particles to achieve rheology control based on the total loading of metal filler particles, robust wetting of various surfaces, and spread control (e.g., limiting or preventing material migration, etc.) in processing and reliability without compromising thermal performance after mixing the copper and nickel particles into the low viscosity gallium indium tin liquid metal alloy.In exemplary embodiments, the method includes using the metal amalgam having the non-refractory filler particles contained therein as a thermal interface material without requiring solder parts or surface treatments to hold the thermal interface material in place and / or wet the surface.In exemplary embodiments, the non-refractory filler particles include the non-refractory metal filler particles. The method includes mixing the non-refractory metal filler particles into the metal amalgam to obtain a pure metal amalgam system in which a stable suspension of the non-refractory metal filler particles in the metal amalgam is maintained.In exemplary embodiments, the method includes applying the metal amalgam having the non-refractory filler particles contained therein to a heat source, another component, or the surface of an electronic device after rheologically controlling the metal amalgam having the non-refractory filler particles.In exemplary embodiments, the method includes using the metal amalgam having the non-refractory filler particles contained therein to establish a thermal bond between a heat source of an electronic device and another component of the electronic device.Also disclosed are example embodiments of thermal interface materials (TIMs) comprising metal amalgam with non-refractory filler particles (e.g., non-refractory metal filler particles, etc.). The thermal interface materials serve to establish a heat path for heat dissipation from a heat source of an electronic device. During operation of the electronic device, heat from the heat source may flow through the heat path, thereby lowering the temperature of the heat source.In example embodiments, the metal amalgam includes non-refractory filler particles (e.g., non-refractory metal filler particles, etc.) whose rheology is controlled without compromising thermal conductivity and maintaining rheology and spread control (e.g., limiting or preventing material migration, etc.) of the thermal interface material.In exemplary embodiments, a stable, homogeneous metal amalgam suspension with viscosity control based on the total loading of filler particles is achieved without compromising the thermal performance of the thermal interface material.In exemplary embodiments, the metal amalgam containing the non-refractory filler particles is rheologically controlled to thereby enable controlled processing of the metal amalgam containing the non-refractory filler particles on a substrate, because the rheology control enables isotropic, uniform spreading of the metal amalgam with the non-refractory filler particles contained therein when pressed between two substrates.In exemplary embodiments, the metal amalgam including the non-refractory filler particles is rheologically controlled to ensure that the metal amalgam remains in place (e.g., does not migrate, leak, pump out, or creep out, etc.) during the thermal reliability test.In exemplary embodiments, the metal amalgam is loaded with the non-heat-resistant filler particles in order to obtain a stable, homogeneous metal amalgam suspension, which leads to an increase in the viscosity of the metal amalgam.In example embodiments, the metal amalgam is loaded with the non-refractory filler particles to thereby achieve rheology control based on the total loading of filler particles, robust wetting of various surfaces, and spread control (e.g., limiting or preventing material migration, etc.) in processing and reliability without compromising thermal performance after mixing the non-refractory filler particles into the metal amalgam.In exemplary embodiments, the metal amalgam is made of a low melting point alloy having a melting point of 160° C. or less.In exemplary embodiments, the non-refractory filler particles are comprised of copper and nickel. The metal amalgam contains about 1 to about 10 percent nickel and copper in the ratio of about 1:1 to about 5:1. the nickel-copper metal amalgam has a thermal conductivity of greater than 15 W / mK, a thermal resistance of less than about 4 mm 2 K / W but not less than about 1 mm 2 K / W, and a viscosity of at most 2800 pascal seconds at a shear rate of 0.5 / s and at most 75 pascal seconds at a shear rate of 5 / s.In example embodiments, the metal amalgam is a gallium-based liquid metal (e.g., a low viscosity gallium indium tin liquid metal alloy or other low viscosity liquid metal). The non-heat-resistant filler particles consist of copper and nickel particles.In exemplary embodiments, the thermal interface material comprises a low viscosity gallium indium tin liquid metal alloy loaded with copper particles and nickel particles to thereby obtain a stable homogeneous metal amalgam suspension that results in an increase in viscosity of the low viscosity gallium indium tin liquid metal alloy.In exemplary embodiments, the thermal interface material is a low viscosity gallium indium tin liquid metal alloy enriched with copper and nickel particles. This achieves rheology control based on the total loading of metal filler particles, robust wetting of various surfaces, and spread control (e.g., limiting or preventing material migration, etc.) in processing and reliability without compromising thermal performance after mixing the copper and nickel particles into the low viscosity gallium indium tin liquid metal alloy.In exemplary embodiments, the metal amalgam including the non-refractory filler particles contained therein does not contain organic solvents and / or organic compounds that otherwise interfere with wetting and / or could result in voids due to outgassing during the temperature change.In exemplary embodiments, the metal amalgam including the non-refractory filler particles contained therein does not include silicone and / or polymer components that could otherwise reduce thermal conductivity.In exemplary embodiments, the metal amalgam including the non-refractory filler particles contained therein is made exclusively of metals.In exemplary embodiments, the non-refractory filler particles include copper and nickel. The metal amalgam has a nickel-copper ratio of about 1:1 to about 5:1 in weight percent (wt %) and / or in volume percent (vol %).In exemplary embodiments, the non-refractory filler particles include copper and nickel. The metal amalgam is loaded with about 1 to about 10% nickel and copper.In exemplary embodiments, the non-refractory filler particles are comprised of copper and nickel. The metal amalgam contains a nickel-copper ratio of about 2:1 weight percent (wt %) and / or volume percent (vol %).In example embodiments, the metal amalgam is made of a gallium indium tin liquid metal alloy. The non-refractory filler particles are comprised of copper and nickel such that the gallium indium tin liquid metal alloy has a nickel-copper ratio of about 1:1 to about 5:1 weight percent (wt %) and / or volume percent (vol %).In exemplary embodiments, the non-refractory filler particles are comprised of copper and nickel. The metal amalgam contains about 5 volume percent (vol %) nickel and about 2.5 volume percent (vol %) copper. In other exemplary embodiments, the metal amalgam is loaded with about 4 volume percent (vol %) nickel and copper.In example embodiments, the thermal interface material comprising the metal amalgam including the non-refractory filler particles may be used to establish a heat path for dissipating heat from a heat source of an electronic device without requiring solder parts or surface treatments to hold the thermal interface material in place during the thermal reliability test (e.g., without migration, bleeding, pumping out or creep from the material, etc.) and / or to wet the surface.In exemplary embodiments, the non-refractory filler particles include non-refractory metal filler particles mixed with the metal amalgam to thereby provide a pure metal amalgam system in which a stable suspension of the non-refractory metal filler particles in the metal amalgam is maintained.In example embodiments, the thermal interface material comprising the metal amalgam with the non-refractory filler particles is distributable on the thermal component or another component of the electronic device.In example embodiments, an electronic device includes a heat source, another component, and a thermal interface material as described herein. The thermal interface material is located between the heat source and the further component and thus forms the heat path via which heat can flow away from the heat source during operation of the electronic device, as a result of which the temperature of the heat source is lowered.To thoroughize this disclosure and to fully convey the scope to those skilled in the art, example embodiments are provided. Numerous specific details, such as examples of specific components, electronic devices, and methods, are set forth in order to provide a thorough understanding of the embodiments of the present disclosure. It will be understood by those skilled in the art that specific details are not required, that example embodiments may be embodied in many different forms, and that neither should be construed as limiting the scope of the disclosure. In some embodiments, known processes, known electronic device structures, and known technologies are not described in detail. Moreover, the advantages and improvements that can be achieved with one or more embodiments of the present disclosure are illustrative only and do not limit the scope of the present disclosure, as the embodiments disclosed herein provide all or none of the above-mentioned advantages and improvements and may still fall within the scope of the present disclosure.The specific dimensions, materials, and / or shapes disclosed herein are exemplary and do not limit the scope of the present disclosure. The values and ranges of values disclosed herein for particular parameters do not exclude other values and ranges of values that may be useful in one or more of the examples disclosed herein. Moreover, it is contemplated that any two values for a parameter referred to herein may define the endpoints of a range of values that may be suitable for the given parameter (i.e., the indication of first and second values for a given parameter may be interpreted such that any value between the first and second values may also be used for the given parameter). For example, if the value A and the value Z are exemplified herein for parameter X, it is contemplated that parameter X may have a range of values from about A to about Z. It is also contemplated that the disclosure of two or more ranges of values for a parameter (whether these ranges are interleaved, overlapping, or different) includes all possible range combinations for the value that could be claimed using the endpoints of the disclosed ranges. If, for example, parameter X here has values in the range of 1-10, 2-9 or 3-8 by way of example, it is also conceivable that parameter X can assume other value ranges, including 1-9, 1-8, 1-3, 1-2, 2-10, 2-8, 2-3, 3-10 and 3-9.The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the / s" also include the plural forms, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and thus specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as implying that their execution in the described or illustrated order is mandatory unless expressly characterized as an execution order. It will also be appreciated that additional or alternative steps may be employed.When an element or layer is referred to as being "on," "engaging," "connected to," or "coupled to" on another element or layer, it may be directly on, engaged with, connected to, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly connected to," "directly connected to," or "directly coupled to" another element or layer, there need be no intervening elements or layers present. Other terms describing the relationship between elements are to be interpreted analogously (e.g., "between" versus "directly between", "adjacent" versus "directly adjacent", etc.). The term "and / or" as used herein includes any and all combinations of one or more of the listed items.The term "about" when used indicates values that the calculation or measurement allows for a slight imprecision of the value (with some approximation to the accuracy of the value; approximately or somewhat close to the value; nearly). If the imprecision provided by "about" is not understood in this usual meaning in experts, "about" here indicates at least deviations that can result from usual measurement or use methods of such parameters. For example, the terms "generally", "about", and "substantially" may be used herein in terms of manufacturing tolerances. Or, for example, as used herein, the term "about" when varying the amount of a component or reactant of the invention or used refers to variations in the amount reading that may occur by typical measurement and handling procedures, for example, in the manufacture of concentrates or solutions in practice, by inadvertent errors in these procedures; by differences in the manufacture, source or purity of the components used to make or carry out the compositions; and the like. The term "about" also includes amounts that vary due to different equilibrium conditions for a composition resulting from a particular feed mixture. Whether modified or not by the term "about", the claims include equivalents to the amounts.Although the terms "first," "second," "third," etc. are used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections are not limited by these terms. These terms are used merely to distinguish an element, component, region, layer, or portion of another region, layer, or portion. Terms such as "first," "second," and other numerical terms do not imply an order herein unless clearly indicated by context. Therefore, a first element, component, region, layer, or portion, as described below, could be referred to as a second element, component, region, layer, or portion without departing from the teachings of the embodiments.Spatially relative terms such as "inner," "outer," "below," "below," "lower," "above," "above," and the like may be used herein to facilitate the description to describe the relationship of an element or feature to one or more other elements or features as depicted in the figures. Spatially relative terms may include other orientations of the electronic device in use or operation in addition to the orientation depicted in the figures. For example, if the electronic device in the figures is turned over, elements described as "below" or "beneath" other elements or features would be oriented "above" the other elements or features. The exemplary term "below" may therefore include both an "upper" and a "lower" orientation. The electronic device may also be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.The foregoing description of the embodiments is illustrative and illustrative. It does not claim completeness or limitation of the disclosure. Individual elements, intended or indicated uses, or features of a particular embodiment are not limited in principle to this embodiment, but may be interchangeable and may be used in a selected embodiment, even if not explicitly shown or described. It can also be varied in many ways. Such variations do not constitute a departure from the disclosure, and all such modifications are included within the scope of the disclosure.

Claims

A thermal interface material comprising a metal amalgam having non-refractory particles.The thermal interface of claim 1, wherein the non-refractory filler particles comprise (non-corrosion resistant) metal filler particles.The thermal interface material of any preceding claim, wherein the metal amalgam contains the non-refractory filler particles for rheological control of the metal amalgam without compromising thermal conductivity while maintaining rheology and spread control and / or limiting or preventing material migration.The thermal interface material of any preceding claim, wherein the thermal interface material comprising the metal amalgam having the non-refractory filler particles is configured to produce a stable, homogeneous viscosity-controlled metal amalgam suspension based on the total loading of filler particles without compromising the thermal performance of the thermal interface material.The thermal interface material according to any one of the preceding claims, wherein the metal amalgam including the non-heat resistant filler particles is rheologically controlled to thereby enable processing of the liquid metal including the non-heat resistant filler particles contained therein on a substrate in a controlled manner, because the rheology control enables isotropic spreading of the metal amalgam including the non-heat resistant filler particles contained therein when pressed between two substratesThe thermal interface material of any preceding claim, wherein the metal amalgam is rheologically controlled with the non-refractory filler particles to allow the metal amalgam to remain with limited or no material migration during the thermal reliability test.The thermal interface material of any preceding claim, wherein the metal amalgam is loaded with the non-refractory filler particles to form a stable, homogeneous metal amalgam suspension that results in an increase in the viscosity of the metal amalgam.The thermal interface material of any preceding claim, wherein the metal amalgam is loaded with non-refractory filler particles to provide rheology control based on total loading of metal filler particles, robust wetting of various surfaces, limited or prevented material migration, and controlled spread during processing and reliability without compromising thermal performance after mixing the non-refractory filler particles into the metal amalgam.The thermal interface material of any preceding claim, wherein the metal amalgam comprises a low melting point alloy having a melting point of at most 160°C.The thermal interface material of any preceding claim, wherein the non-refractory filler particles comprise copper and nickel; the metal amalgam is loaded with about 1 to about 10 percent nickel and copper in a ratio of nickel to copper in the range of about 1:1 to about 5:1; and the metal amalgam, including nickel and copper, has a thermal conductivity greater than 15 W / mK, a thermal resistance less than about 4 mm 2 K / W but not less than about 1 mm 2 K / W, and a viscosity of at most 2800 pascal seconds at a shear rate of 0.5 / s and at most 75 pascal seconds at a shear rate of 5 / s.The thermal interface material of any preceding claim, wherein the metal amalgam comprises a gallium-based liquid metal; and the non-refractory filler particles comprise copper and nickel particles.The thermal interface material of claim 11, wherein the gallium-based liquid metal comprises a low viscosity gallium indium tin liquid metal alloy; and the low viscosity gallium indium tin liquid metal alloy is loaded with the copper and nickel particles to obtain a stable, homogeneous metal amalgam suspension that results in an increase in viscosity of the low viscosity gallium indium tin liquid metal alloy.The thermal interface material of claim 11 or 12, wherein the gallium-based liquid metal comprises a low viscosity gallium indium tin liquid metal alloy; the low viscosity gallium indium tin liquid metal alloy is loaded with copper and nickel particles to achieve rheology control based on total loading of metal filler particles, robust wetting of various surfaces, limited or prevented material migration, and controlled spread in processing and reliability without sacrificing thermal performance after mixing the copper and nickel particles into the low viscosity gallium indium tin liquid metal alloy.The thermal interface material of any preceding claim, wherein the thermal interface material can be used to establish a thermal path for heat dissipation from a heat source of an electronic device without requiring solder parts or surface treatments to hold the thermal interface material in place with limited or no material migration and / or wet the surface.The thermal interface material of any preceding claim, wherein the metal amalgam including the non-refractory filler particles contained therein does not contain organic solvents and / or organic compounds that could otherwise reduce wetting and / or result in voids due to outgassing during the temperature cycle.The thermal interface material of any preceding claim, wherein the metal amalgam including the non-refractory filler particles contained therein does not contain silicone and / or polymer components that could otherwise reduce thermal conductivity.The thermal interface material of any preceding claim, wherein the non-refractory filler particles are non-refractory metal filler particles that are mixed with the metal amalgam to form a pure metal amalgam system in which a stable suspension of the non-refractory metal filler particles in the metal amalgam is maintained.The thermal interface material of any preceding claim, wherein the thermal interface material is unnecessary on the heating component or another component of the electronic device.The thermal interface material according to any preceding claim, wherein the metal amalgam including the non-refractory filler particles contained therein is made of metals alone.The thermal interface material of any preceding claim, wherein the non-refractory filler particles comprise copper and nickel; and the metal amalgam has a nickel-copper ratio of about 1:1 to about 5:1 weight percent (wt%) and / or volume percent (vol%).The thermal interface material of any preceding claim, wherein the non-refractory filler particles comprise copper and nickel; and the metal amalgam is loaded with about 1 to about 10% nickel and copper.The thermal interface material of any preceding claim, wherein the non-refractory filler particles comprise copper and nickel such that the metal amalgam has a nickel-copper ratio of about 2:1 weight percent (wt%) and / or volume percent (vol%).The thermal interface material of any preceding claim, wherein the metal amalgam comprises a gallium indium tin metal alloy liquid; and the non-refractory filler particles comprise copper and nickel such that the gallium indium tin liquid metal alloy has a ratio of nickel to copper in a range of about 1:1 to about 5:1 in weight percent (wt %) and / or in volume percent (vol %).The thermal interface material of any preceding claim, wherein the thermal interface material is positionable between a heat source of an electronic device and another component of the electronic device to thereby form a heat path through which heat from the heat source may flow during operation of the electronic device, thereby lowering the temperature of the heat source.An electronic device comprising the heat source, the other component and the thermal interface material of any preceding claim positioned between the heat source and the other component to thereby form the thermal path through which heat may flow from the heat source during operation of the electronic device, thereby lowering the temperature of the heat source.

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