Methods for applying metal amalgams for performance enhancement as thermal interface materials

Abstract

Disclosed are exemplary methods for applying metal amalgams for performance enhancement as thermal interface materials. In exemplary embodiments, a method comprises stenciling or screen printing first and second metal amalgams onto respective first and second opposing thermal transfer surfaces, sides, or substrates in a thermal joint, e.g., within an electronic device. The first and second metal amalgams may establish a thermal path through which heat is flowable from the first thermal transfer surface or substrate (e.g., heat source, etc.) to the first metal amalgam, from the first metal amalgam to the second metal amalgam, and from the second metal amalgam to the second thermal transfer surface or substrate (e.g., heat sink, heat spreader, other heat removal / dissipation structure, etc.). The double-sided printing method allows the metal amalgams to provide robust wetting and surface coverage of both the first and second opposing thermal transfer surfaces, sides, or substrates defining the thermal joint.

Description

Docket No. 9062D-000622-WO-POAMETHODS FOR APPLYING METAL AMALGAMS FOR PERFORMANCE ENHANCEMENT AS THERMAL INTERFACE MATERIALSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 760,805 filed February 20, 2025, which is incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure generally relates to methods for applying metal amalgams for performance enhancement as thermal interface materials (TIMs).BACKGROUND

[0003] This section provides background information related to the present disclosure which is not necessarily prior art.

[0004] Electrical components, such as semiconductors, integrated circuit packages, transistors, etc., typically have pre-designed temperatures at which the electrical components optimally operate. Ideally, the pre-designed temperatures approximate the temperature of the surrounding air. But the operation of electrical components generates heat. If the heat is not removed, the electrical components may then operate at temperatures significantly higher than their normal or desirable operating temperature. Such excessive temperatures may adversely affect the operating characteristics of the electrical components and the operation of the associated electronic device.

[0005] To avoid or at least reduce the adverse operating characteristics from the heat generation, the heat should be removed, for example, by conducting the heat from the operating electrical component to a heat sink. The heat sink may then be cooled by conventional convection and / or radiation techniques. During conduction, the heat may pass from the operating electrical component to the heat sink either by direct surface contact between the electrical component and heat sink and / or by contact of the electrical component and heat sink surfaces through an intermediate medium or thermal interface material. The thermal interface material may be used to fill the gap between thermalDocket No. 9062D-000622-WO-POAtransfer surfaces, in order to increase thermal transfer efficiency as compared to having the gap filled with air, which is a relatively poor thermal conductor.DRAWINGS

[0006] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0007] FIG. 1 shows first and second metal amalgams applied to respective first and second glass substrates using an exemplary stenciling / screen printing method according to exemplary embodiments disclosed herein.

[0008] FIG. 2 shows the first and second metal amalgams after the first and second glass substrates have been pressed together, thereby simulating a thermal joint defined by the first and second substrates and the first and metal amalgams therebetween.

[0009] FIG. 3 graphically illustrates thermal resistance (Rth) (°Ocm2 / W) versus pressure in pounds per square inch (psi) measured (according to ASTM D5470) for first and second metal amalgams (Rth Double Sided) stenciled or screen printed onto respective first and second thermal transfer surfaces, sides, or substrates in a thermal joint using an exemplary double-sided application method disclosed herein. For comparison purposes, FIG. 3 also includes thermal resistance versus pressure measured (according to ASTM D5470) for the same metal amalgam (Rth Single Sided) that was applied using a conventional single-sided application method.

[0010] FIGS. 4A though 4F shows a step by step stenciling / screen printing process that would be performed on first and second opposing thermal transfer surfaces, sides, or substrates in a thermal joint during a double-sided stenciling / screen printing (broadly, double-sided printing) application method according to exemplary embodiments disclosed herein.

[0011] FIG. 5 shows removal of a piece of the tape (e.g., KAPTON® tape, polyimide film with silicone adhesive, etc.) that was applied to the substrate to set the desired stencil area for the metal amalgam as shown in FIG. 4.Docket No. 9062D-000622-WO-POADETAILED DESCRIPTION

[0012] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0013] When assembling devices containing liquid metal thermal interface materials (TIMs), the device assembly processes can cause uneven forces to be exerted on the liquid metal TIM material. This can be problematic as the uneven lidding process can cause the liquid metal to spread unevenly upon assembly and prevent optimal surface coverage on both thermal transfer surfaces, sides, or substrates in a thermal joint. This can lead to failure in surface coverage and limit thermal performance due to the lack of wetting on both thermal transfer surfaces, sides, or substrates of the thermal joint.

[0014] After recognizing the above, exemplary embodiments were developed and / or are disclosed herein of exemplary methods (e.g., double-sided printing methods, etc.) for applying metal amalgams for performance enhancement as thermal interface materials (TIMs) (e.g.,. reduced thermal resistance, robust wetting and surface coverage of opposing thermal transfer surfaces or sides of thermal joints, etc.). In exemplary embodiments, a method comprises stenciling or screen printing first and second metal amalgams onto respective first and second thermal transfer surfaces, sides, or substrates for a thermal joint, e.g., within an electronic device, etc.

[0015] The first and second metal amalgams may establish a thermal path through which heat is flowable from the first thermal transfer surface or substrate (e.g, heat source, etc.) to the first metal amalgam, from the first metal amalgam to the second metal amalgam, and from the second metal amalgam to the second thermal transfer surface or substrate (e.g., heat sink, heat spreader, other heat removal / dissipation structure, etc.). Accordingly, heat may be flowable through the thermal path from the heat source or other first thermal transfer surface or substrate via the first and second metal amalgams to the heat sink, heat spreader, or other second thermal transfer surface or substrate during operation of an electronic device whereby temperature of the heat source may be reduced.

[0016] The first and second metal amalgams may comprise the same metal amalgam or different metal amalgams. By way of example, the first and / or second metal amalgam may comprise a gallium-based liquid metal (e.g. gallium-indium-tin liquid metal alloy including nickel particles and copperparticles, etc.), a metal amalgam including fillerDocket No. 9062D-000622-WO-POAparticles (e.g., non-refractory filler particles, non-refractoiy metal filler particles, metal filler particles, other filler particles, etc.), etc.

[0017] The exemplary methods disclosed herein allow metal amalgams to provide robust wetting and surface coverage of both the first and second opposing thermal transfer surfaces, sides, or substrates defining a thermal j oint. And the thermal performance of the metal amalgams are enhanced, e.g., double sided processing methods disclosed herein allows for a thermal resistance reduction of about three times compared to a single sided processing method. Processing the liquid metal amalgam on both substrate surfaces using the exemplary methods disclosed herein allows for the material to hold in place upon a device uneven assembly process. The exemplary methods disclosed herein allows for high surface coverage of liquid metal and precise placement inside thermal interface joint. The exemplary methods disclosed herein allows for no sacrifice in thermal conductivity and thermal resistance of the metal amalgam while still maintaining surface coverage and spreading control. The exemplary methods disclosed herein allows for controlled Bond Line Thicknesses of the metal amalgam based on initial processing thickness.

[0018] Additionally, the exemplary double-sided printing methods disclosed herein allow for forgiving and precise placement of the metal amalgams during the uneven lidding process in device assembly. For example, a controlled minimum or reduced bond line thickness less than 100 micrometers is achievable using the exemplary double-sided printing methods disclosed herein with optimal coverage down to 25 micrometer or less initial application thickness, thereby solving a thickness challenge when applying gallium-based liquid metal amalgams.

[0019] As noted above, the double-sided printing methods disclosed herein may be used to apply first and second metal amalgams via stenciling or screen printing onto respective first and second opposing thermal transfer surfaces, sides, or substrates for a thermal joint. By way of example, the double-sided printing methods disclosed herein may be used to apply metal amalgams via stenciling or screen printing onto a heat source (e.g., an integrated circuit or other component of an electronic device, etc.), heat removal / dissipation structure (e.g., a heat sink, a heat spreader, a heat pipe, a vapor chamber, a device exterior case, a housing, a chassis, etc.), a component of a solid-stateDocket No. 9062D-000622-WO-POAdrive, a board level shield, and / or other substrates defining thermal transfer surfaces in a thermal j oint.

[0020] By way of example, the first and / or second metal amalgam may comprise gallium-indium-tin liquid metal alloy (or other liquid metal, low melting alloy, etc.) including about 1 percent to about 10 percent of nickel and copper particles (e. ., about 4 volume percent (vol%) of nickel particles and copper particles, etc.). The filler particle loading may be sufficiently low to enable the metal amalgam to be dispensable, e.g., onto a heat source (e.g., an integrated circuit or other component of an electronic device, etc.), heat removal / dissipation structure (e.g., a heat sink, a heat spreader, a heat pipe, a vapor chamber, a device exterior case, a housing, a chassis, etc.), a component of a solid-state drive, a board level shield, and / or other substrates defining thermal transfer surfaces in a thermal joint.

[0021] With reference now to the figures, FIG. 1 shows first and second metal amalgams applied to respective first and second glass substrates using an exemplary stenciling / screen printing method according to exemplary embodiments disclosed herein. FIG. 2 shows the first and second metal amalgams after the first and second glass substrates have been pressed together, thereby simulating a thermal joint defined by the first and second glass substrates and the first and metal amalgams therebetween.

[0022] As the first and second substrates are pressed together, the metal amalgam material did not leach out of its original processed area. In the context of a thermal joint, this is advantageous because the metal amalgam material is remaining in the thermal joint during assembly, which is a challenge when working with gallium liquid metals.

[0023] FIGS. 1 and 2 show the excellent surface coverage control achievable when metal amalgams are applied using the exemplary double-sided stenciling / screen printing (broadly, double-sided printing) application methods disclosed herein. As also shown in FIG. 2, the metal amalgams maintained desired surface coverage area and maintained robust surface contact on both sides when pressed between the first and second glass substrates.

[0024] FIG. 3 graphically illustrates thermal resistance (Rth) (°Ocm2 / W) versus pressure in pounds per square inch (psi) measured (according to ASTM D5470) for first and second metal amalgams (Rth Double Sided) stenciled or screen printed ontoDocket No. 9062D-000622-WO-POArespective first and second thermal transfer surfaces, sides, or substrates in a thermal joint using an exemplary double-sided application method disclosed herein. For comparison purposes, FIG. 3 also includes thermal resistance versus pressure measured (according to ASTM D5470) for the same metal amalgam (Rth Single Sided) that was applied using a conventional single-sided application method.

[0025] As shown by FIG. 3, the thermal resistance of the metal amalgams (Rth Double Sided) applied using used the double-sided application method had a significantly lower thermal resistance (e.g., 3 times less, etc.) than the thermal resistance of the same metal amalgam (Rth Single Sided) applied using the conventional single-sided application method. In this example shown in FIG. 3, the metal amalgams comprised low viscosity gallium-indium-tin liquid metal alloy loaded with about 1 percent to about 10 percent of nickel and copper at a ratio of the nickel to the copper within a range from about 1:1 to about 5:1.

[0026] FIG. 4 shows a step by step stenciling / screen printing process (e.g., manual process, automatic process performed by a system, etc.) that would be performed on first and second opposing thermal transfer surfaces, sides, or substrates for a thermal joint during a double-sided stenciling / screen printing (broadly, double-sided printing) application method according to exemplary embodiments disclosed herein.

[0027] As shown in FIG. 4A, first and second strips of tape (e.g., KAPTON® tape, polyimide film with silicone adhesive, etc.) are applied to a substrate such that the first and second strips of tape are generally parallel with each other and define a desired substrate area for the metal amalgam. The distance or space separating the first and second strips of tape from each other define a width of the stencil for the metal amalgam.

[0028] As shown in FIG. 4B, third and fourth strips of tape (e.g., KAPTON® tape, polyimide film with silicone adhesive, etc.) are applied to the substrate such that the third and fourth strips of tape are generally parallel with each other and generally perpendicular to the first and second strips of tape. The third and fourth strips of tape define or set the desire stencil area for the metal amalgam. The distance or space separating the third and fourth strips of tape from each other define a length of the stencil for the metal amalgam. And the thickness defined by the strips of tape along the right and left edge portions of the stencil also set or establish the thickness / height for the metal amalgam.Docket No. 9062D-000622-WO-POA

[0029] Metal amalgam may then be applied to the substrate within the stencil area defined by the first, second, third, and fourth strips of tape. For example, a droplet of the metal amalgam may be dispensed along a left side portion of the stencil area as shown in FIG. 4C.

[0030] As shown in FIG. 4D, the metal amalgam may be spread across the stencil area defined by the first, second, third, and fourth strips of tape. For example, the droplet of the metal amalgam may be dispensed from left to right across the stencil area, e.g., by using a blade (e.g., plastic blade, metal blade, etc.), squeegee, edge, or roller (broadly, device), etc.

[0031] A blade (e.g., plastic blade, metal blade, etc.), squeegee, edge, or roller (broadly, device) may then be moved (e.g. , dragged, etc.) across the metal amalgam relative to the stencil to generate a relatively uniform layer of the metal amalgam as shown in FIG.4E. As the blade, squeegee, edge, or roller is moved across the metal amalgam, the blade, squeegee, edge, or roller may be operable for configuring (e.g., weakening, thinning, severing, cutting, imprinting, etc.) the outermost edges of the stenciled uniform layer of the metal amalgam such that excess metal amalgam material that is outside of the outermost edges may be easier to remove when the tape stencil is removed and such that it may be easier for the stenciled uniform layer of the metal amalgam to remain on the substrate as the tape stencil is removed.

[0032] The tape may then be slowly removed to thereby generate a uniform metal amalgam stenciled layer on the substrate as shown in FIG. 4F. By way of example, the uniform metal amalgam stenciled layer on the substrate may have a substantially uniform or constant thickness, e.g., a controlled minimum or reduced bond line thickness less than 100 micrometers, optimal coverage down to 25 micrometer or less initial application thickness, etc. When the tape is removed, excess metal amalgam material that exceeded the set gap, thickness, or height established by the tape stencil is removed as that excess metal amalgam remains on the tape as the tape is being removed.

[0033] After the process shown in FIGS. 4A through 4F is completed and the first metal amalgam stenciled layer has been applied on the first substrate, the process may then repeated to apply a second metal amalgam stenciled layer onto a second substrate. In such exemplary embodiments, the first and second substrates may comprise a heat sourceDocket No. 9062D-000622-WO-POA(e.g., an integrated circuit or other component of an electronic device, etc.), heat removal / dissipation structure (e.g., a heat sink, a heat spreader, a heat pipe, a vapor chamber, a device exterior case, a housing, a chassis, etc.), a component of a solid-state drive, a board level shield, and / or other substrates defining thermal transfer surfaces in a thermal joint. And first and second metal amalgams may comprise the same metal amalgam or different metal amalgams. By way of example, the first and / or second metal amalgam may comprise a gallium-based liquid metal e.g. gallium-indium-tin liquid metal alloy including nickel particles and copper particles, etc.), a metal amalgam including filler particles e.g., non-refractory filler particles, non-refractoiy metal filler particles, metal filler particles, other filler particles, etc.), other liquid metal amalgam, etc.

[0034] In exemplary embodiments, the first and second metal amalgams comprise generally rectangular stenciled layers on the respective first and second thermal transfer surfaces, sides, or substrates. But in other exemplary embodiments, either or both of the first and / or second metal amalgam may comprise a non-rectangular stenciled layer on a thermal transfer surface, side, or substrate.

[0035] FIG. 5 shows removal of a piece of the tape (e.g., KAPTON® tape, polyimide film with silicone adhesive, etc.) that was applied to the substrate to set the desired stencil area for the metal amalgam. As shown in FIG. 4, tape was applied to the substrate to set the desired stencil area on the substrate for the metal amalgam including the stencil’s length, width, and thickness / height for the metal amalgam. A blade (e.g., plastic blade, metal blade, etc.), squeegee, edge, or roller (broadly, device) was moved across metal amalgam relative to the stencil to remove excess metal amalgam material that was above the height or thickness of the stencil as set by the tape thickness. When the tape is removed as shown in FIG. 5, excess metal amalgam material that exceeded the set gap, thickness, or height established by the tape stencil is removed as that excess metal amalgam remains on the tape as the tape is being removed.

[0036] In the exemplary embodiment of FIGS. 4 and 5, strips or pieces of tape (e.g., KAPTON® tape, polyimide film with silicone adhesive, etc.) were used for defining the stencil area on the substrate. In other exemplary embodiments, other stencil liner materials (e.g., polyethylene terephthalate (PET) with or without adhesive, other tapes, other adhesive materials, other non-adhesive materials, etc.) may be used instead of or inDocket No. 9062D-000622-WO-POAaddition to tape to define stencil areas on thermal transfer surfaces, sides, or substrates. For example, PET cut out stencils without adhesives may be used in other exemplary embodiments.

[0037] Disclosed are exemplary methods ( e.g., double-sided printed methods, etc.) of applying metal amalgams for performance enhancement as thermal interface materials.

[0038] In exemplary embodiments, a method comprises applying first and second metal amalgams onto respective first and second thermal transfer surfaces for use as thermal interface materials in a thermal joint. The step or process of applying the first metal amalgam onto the first thermal transfer surface includes stenciling the first metal amalgam onto the first thermal transfer surface. And the step or process of applying the second metal amalgam onto the second thermal transfer surface includes stenciling the second metal amalgam onto the second thermal transfer surface.

[0039] In exemplary embodiments, a method comprises applying first and second metal amalgams onto respective first and second thermal transfer surfaces for use as thermal interface materials in a thermal joint. The step or process of applying the first metal amalgam onto the first thermal transfer surface includes screen printing the first metal amalgam onto the first thermal transfer surface. And the step or process of applying the second metal amalgam onto the second thermal transfer surface includes screen printing the second metal amalgam onto the second thermal transfer surface.

[0040] In exemplary embodiments, a method comprises applying first and second metal amalgams onto respective first and second thermal transfer surfaces for use as thermal interface materials in a thermal joint. The step or process of applying the first metal amalgam onto the first thermal transfer surface includes: using a first stencil to define a first stencil area along the first thermal transfer surface for the first metal amalgam; applying the first metal amalgam within the first stencil area defined along the first thermal transfer surface; spreading the first metal amalgam across the first stencil area defined along the first thermal transfer surface; moving a blade, squeegee, or other edge across an upper surface of the first metal amalgam relative to the first stencil area to thereby generate a relatively uniform layer of the first metal amalgam within the first stencil area defined along the first thermal transfer surface; and removing the first stencil from the first thermalDocket No. 9062D-000622-WO-POAtransfer surface such that excess first metal amalgam material that exceeded the gap, thickness, or height established by the first stencil is removed as the excess metal amalgam remains on the first stencil as the first stencil is removed and such that the relatively uniform layer of the first metal amalgam remains on the first thermal transfer surface. The step or process of applying the second metal amalgam onto the second thermal transfer surface includes: using a second stencil to define a second stencil area along the second thermal transfer surface for the second metal amalgam; applying the second metal amalgam within the second stencil area defined along the second thermal transfer surface; spreading the second metal amalgam across the second stencil area defined along the second thermal transfer surface; moving a blade, squeegee, or other edge across an upper surface of the second metal amalgam relative to the second stencil area to thereby generate a relatively uniform layer of the second metal amalgam within the second stencil area defined along the second thermal transfer surface; and removing the second stencil from the second thermal transfer surface such that excess second metal amalgam material that exceeded the gap, thickness, or height established by the second stencil is removed as the excess metal amalgam remains on the second stencil as the second stencil is removed and such that the relatively uniform layer of the second metal amalgam remains on the second thermal transfer surface.

[0041] In exemplary methods, the first and second metal amalgams comprise first and second liquid metals. The step or process of applying the first metal amalgam within the first stencil area defined along the first thermal transfer surface comprises dispensing a droplet of the first liquid metal within the first stencil area defined along the first thermal transfer surface. And the step or process of applying the second metal amalgam within the second stencil area defined along the second thermal transfer surface comprises dispensing a droplet of the second liquid metal within the second stencil area defined along the second thermal transfer surface. The method may also include spreading the first metal amalgam across the first stencil area defined along the first thermal transfer surface comprises spreading the droplet of the first liquid metal within the first stencil area defined along the first thermal transfer surface; and spreading the second metal amalgam across the second stencil area defined along the second thermal transfer surface comprisesDocket No. 9062D-000622-WO-POAspreading the droplet of the second liquid metal within the second stencil area defined along the second thermal transfer surface.

[0042] In exemplary embodiments, the method includes: using tape to define the first stencil area along the first thermal transfer surface for the first metal amalgam; and using tape to define the second stencil area along the second thermal transfer surface for the second metal amalgam.

[0043] In exemplary embodiments, the method includes: using KAPTON® tape to define the first stencil area along the first thermal transfer surface for the first metal amalgam; and using KAPTON® tape to define the second stencil area along the second thermal transfer surface for the second metal amalgam.

[0044] In exemplary embodiments, the method includes: using polyimide film with silicone adhesive to define the first stencil area along the first thermal transfer surface for the first metal amalgam; and using polyimide film with silicone adhesive to define the second stencil area along the second thermal transfer surface for the second metal amalgam.

[0045] In exemplary embodiments, the method includes: using a first polyethylene terephthalate (PET) cut out stencil without adhesive to define the first stencil area along the first thermal transfer surface for the first metal amalgam; and using a second polyethylene terephthalate (PET) cut out stencil without adhesive to define the second stencil area along the second thermal transfer surface for the second metal amalgam.

[0046] In exemplary embodiments, the method includes defining the first stencil area along the first thermal transfer surface for the first metal amalgam by: applying first and second strips of tape to the first thermal transfer surface such that the first and second strips of tape are generally parallel with each other and define a desired area for the first metal amalgam along the first thermal transfer surface, whereby the distance separating the first strip of tape from the second strip of tape defines a width of the first stencil area for the first metal amalgam; and applying third and fourth strips of tape to the first thermal transfer surface such that the third and fourth strips of tape are generally parallel with each and generally perpendicular to the first and second strips of tape, whereby the distance separating the third strip of tape from the fourth strip of tape defines a length of the first stencil area for the first metal amalgam, and whereby the thickness ofDocket No. 9062D-000622-WO-POAthe strips of tape defines a thickness / height of the first stencil area for the first metal amalgam.

[0047] The method may further include defining the second stencil area along the second thermal transfer surface for the second metal amalgam by: applying fifth and sixth strips of tape to the second thermal transfer surface such that the fifth and sixth strips of tape are generally parallel with each other and define a desired area for the second metal amalgam along the second thermal transfer surface, whereby the distance separating the fifth strip of tape from the sixth strip of tape defines a width of the second stencil area for the second metal amalgam; and applying seventh and eighth strips of tape to the second thermal transfer surface such that the seventh and eighth strips of tape are generally parallel with each and generally perpendicular to the fifth and sixth strips of tape, whereby the distance separating the seventh strip of tape from the eighth strip of tape defines a length of the second stencil area for the second metal amalgam, and whereby the thickness of the strips of tape defines a thickness / height of the second stencil area for the second metal amalgam.

[0048] In exemplary embodiments, the method includes defining the first stencil area along the first thermal transfer surface for the first metal amalgam by: applying first and second pieces of material to the first thermal transfer surface such that the first and second pieces of material are generally parallel with each other and define a desired area for the first metal amalgam along the first thermal transfer surface, whereby the distance separating the first piece of material from the second piece of material defines a width of the first stencil area for the first metal amalgam; and applying third and fourth pieces of material to the first thermal transfer surface such that the third and fourth pieces of material are generally parallel with each and generally perpendicular to the first and second pieces of material, whereby the distance separating the third piece of material from the fourth piece of material defines a length of the first stencil area for the first metal amalgam, and whereby the thickness of the pieces of material defines a thickness / height of the first stencil area for the first metal amalgam.

[0049] The method may further include defining the second stencil area along the second thermal transfer surface for the second metal amalgam by: applying fifth and sixth pieces of material to the second thermal transfer surface such that the fifth and sixthDocket No. 9062D-000622-WO-POApieces of material are generally parallel with each other and define a desired area for the second metal amalgam along the second thermal transfer surface, whereby the distance separating the fifth piece of material from the sixth piece of material defines a width of the second stencil area for the second metal amalgam; and applying seventh and eighth pieces of material to the second thermal transfer surface such that the seventh and eighth pieces of material are generally parallel with each other and generally perpendicular to the fifth and sixth pieces of material, whereby the distance separating the seventh piece of material from the eighth piece of material defines a length of the second stencil area for the second metal amalgam, and whereby the thickness of the pieces of material defines a thickness / height of the second stencil area for the second metal amalgam.

[0050] In exemplary embodiments, the first metal amalgam on the first thermal transfer surface has a bond line thickness of less than 100 micrometers; and / or the second metal amalgam on the second thermal transfer surface has a bond line thickness of less than 100 micrometers.

[0051] In exemplary embodiments, the first metal amalgam on the first thermal transfer surface has an initial application thickness of 25 micrometers or less; and / or the second metal amalgam on the second thermal transfer surface has an initial application thickness of 25 micrometers or less.

[0052] In exemplary embodiments, the first and second metal amalgams comprise the same metal amalgam or different metal amalgams.

[0053] In exemplary embodiments, either or both of the first and second metal amalgams comprises a gallium-based liquid metal.

[0054] In exemplary embodiments, either or both of the first and second metal amalgams comprises a liquid metal filled with metal filler particles.

[0055] In exemplary embodiments, either or both of the first and second metal amalgams consists of only metal(s).

[0056] In exemplary embodiments, either or both of the first and second metal amalgams comprises gallium, indium, tin, nickel, and copper.

[0057] In exemplary embodiments, either or both of the first and second metal amalgams comprises gallium-indium-tin liquid metal alloy including nickel particles and copper particles.Docket No. 9062D-000622-WO-POA

[0058] In exemplary embodiments, either or both of the first and second metal amalgams comprises nickel particles and copper particles with a ratio of the nickel to the copper within a range from about 1:1 to about 5:1 by weight percent (wt%) and / or by volume percent (vol%).

[0059] In exemplary embodiments, either or both of the first and second metal amalgams comprises nickel particles and copper particles with about a 2: 1 ratio of nickel to copper by weight percent (wt%) and / or by volume percent (vol%).

[0060] In exemplary embodiments, either or both of the first and second metal amalgams comprises about 1 percent to about 10 percent of nickel and copper particles.

[0061] In exemplary embodiments, the method includes using the first and second metal amalgams to establish a thermal path through which heat is flowable from the first thermal transfer surface to the first metal amalgam, from the first metal amalgam to the second metal amalgam, and from the second metal amalgam to the second thermal transfer surface.

[0062] In exemplary embodiments, the first and / or second thermal transfer surfaces are defined by one or more of: a heat removal / dissipation structure; a heat source of an electronic device; a component of a solid-state drive; and / or a board level shield.

[0063] In exemplary embodiments, the first thermal transfer surface is defined by a heat removal / dissipation structure such as a heat sink, a heat spreader, a heat pipe, a vapor chamber, a device exterior case, a housing, or a chassis. And the second thermal transfer surface is defined by a heat source of an electronic device such as an integrated circuit or other component of the electronic device.

[0064] In exemplary embodiments, the method of applying the first and second metal amalgams to the respective first and thermal transfer surfaces: enables the first and second metal amalgams to provide robust wetting and surface coverage of the first and second opposing thermal transfer surfaces; reduces thermal resistance of the first and second metal amalgams by at least about three times as compared to the same metal amalgam applied to a thermal transfer surface via a single-sided conventional method; enables the first and second metal amalgams hold in place during device uneven assembly process; allows for high surface coverage of liquid metal and precise placement inside a thermal joint; allows for no sacrifice in thermal conductivity and thermal resistance of theDocket No. 9062D-000622-WO-POAmetal amalgam while still maintaining surface coverage and spreading control; and / or allows for controlled Bond Line Thicknesses of the metal amalgam based on initial processing thickness.[0065J In exemplary embodiments, a thermal interface material assembly is usable for establishing a thermal path for conducting heat from a heat source of an electronic device to another component of the electronic device. The heat source defines a first thermal transfer surface. The another component defines a second thermal transfer surface. The thermal interface material assembly comprises first and second metal amalgams applied to the respective first and second thermal transfer surfaces according to a method as disclosed herein. Heat is flowable through the thermal path from the heat source to the another component via the first and second metal amalgams during operation of the electronic device whereby temperature of the heat source is reduced.

[0066] In exemplary embodiments, an electronic device comprises a heat source defining a first thermal transfer surface, and another component defining a second thermal transfer surface. First and second metal amalgams are applied to the respective first and second thermal transfer surfaces according to a method as disclosed herein. Heat is flowable from the heat source to the another component via the first and second metal amalgams during operation of the electronic device whereby temperature of the heat source is reduced. The another component may comprise a heat removal / dissipation structure such as a heat sink, a heat spreader, a heat pipe, a vapor chamber, a device exterior case, a housing, or a chassis. And the heat source may comprise an integrated circuit or other component of the electronic device.

[0067] In exemplary embodiments, a system is configured for performing various steps or processes of an exemplary method disclosed herein. For example, the system may configured for automatically performing ( e.g., with little or without manual performance by a human operator, etc.) various steps or processes of an exemplary method disclosed herein.

[0068] Various aspects of the invention according to the present disclosure include, but are not limited to, the aspects listed in the following numbered clauses.

[0069] Clause 1. A method comprising applying first and second metal amalgams onto respective first and second thermal transfer surfaces for use as thermalDocket No. 9062D-000622-WO-POAinterface materials in a thermal joint, wherein: applying the first metal amalgam onto the first thermal transfer surface includes stenciling and / or screen printing the first metal amalgam onto the first thermal transfer surface; and applying the second metal amalgam onto the second thermal transfer surface includes stenciling and / or screen printing the second metal amalgam onto the second thermal transfer surface.

[0070] Clause 2. The method of clause 1, wherein applying the first metal amalgam onto the first thermal transfer surface includes: using a first stencil to define a first stencil area along the first thermal transfer surface for the first metal amalgam; and applying the first metal amalgam within the first stencil area defined along the first thermal transfer surface.

[0071] Clause 3. The method of clause 2, wherein applying the first metal amalgam onto the first thermal transfer surface includes: spreading the first metal amalgam across the first stencil area defined along the first thermal transfer surface; moving a blade, squeegee, or other edge across an upper surface of the first metal amalgam relative to the first stencil area to thereby generate a relatively uniform layer of the first metal amalgam within the first stencil area defined along the first thermal transfer surface; and removing the first stencil from the first thermal transfer surface such that excess first metal amalgam material that exceeded the gap, thickness, or height established by the first stencil is removed as the excess metal amalgam remains on the first stencil as the first stencil is removed and such that the relatively uniform layer of the first metal amalgam remains on the first thermal transfer surface.

[0072] Clause 4. The method of clause 2 or 3, wherein: the first metal amalgam comprises a first liquid metal; and applying the first metal amalgam onto the first thermal transfer surface includes: dispensing a droplet of the first liquid metal within the first stencil area defined along the first thermal transfer surface; and spreading the droplet of the first liquid metal within the first stencil area defined along the first thermal transfer surface.

[0073] Clause 5. The method of any one of clauses 1 to 4, wherein applying the second metal amalgam onto the second thermal transfer surface includes: using a second stencil to define a second stencil area along the second thermal transfer surface for the second metal amalgam; and applying the second metal amalgam within the second stencil area defined along the second thermal transfer surface.Docket No. 9062D-000622-WO-POA

[0074] Clause 6. The method of clause 5, wherein applying the second metal amalgam onto the second thermal transfer surface includes: spreading the second metal amalgam across the second stencil area defined along the second thermal transfer surface; moving a blade, squeegee, or other edge across an upper surface of the second metal amalgam relative to the second stencil area to thereby generate a relatively uniform layer of the second metal amalgam within the second stencil area defined along the second thermal transfer surface; and removing the second stencil from the second thermal transfer surface such that excess second metal amalgam material that exceeded the gap, thickness, or height established by the second stencil is removed as the excess metal amalgam remains on the second stencil as the second stencil is removed and such that the relatively uniform layer of the second metal amalgam remains on the second thermal transfer surface.

[0075] Clause 7. The method of clause 6, wherein: the second metal amalgam comprises a second liquid metal; and applying the second metal amalgam onto the second thermal transfer surface includes: dispensing a droplet of the second liquid metal within the second stencil area defined along the second thermal transfer surface; and spreading the droplet of the second liquid metal within the second stencil area defined along the second thermal transfer surface.

[0076] Clause 8. The method of any one of clauses 1 to 7, wherein the method includes: using tape to define a first stencil area along the first thermal transfer surface for the first metal amalgam; and using tape to define a second stencil area along the second thermal transfer surface for the second metal amalgam.

[0077] Clause 9. The method of any one of clauses 1 to 7, wherein the method includes: using KAPTON® tape to define a first stencil area along the first thermal transfer surface for the first metal amalgam; and using KAPTON® tape to define a second stencil area along the second thermal transfer surface for the second metal amalgam.

[0078] Clause 10. The method of any one of clauses 1 to 7, wherein the method includes: using polyimide film with silicone adhesive to define a first stencil area along the first thermal transfer surface for the first metal amalgam; and using polyimide film with silicone adhesive to define a second stencil area along the second thermal transfer surface for the second metal amalgam.Docket No. 9062D-000622-WO-POA

[0079] Clause 11. The method of any one of clauses 1 to 7, wherein the method includes: using a first polyethylene terephthalate (PET) cut out stencil without adhesive to define a first stencil area along the first thermal transfer surface for the first metal amalgam; and using a second polyethylene terephthalate (PET) cut out stencil without adhesive to define a second stencil area along the second thermal transfer surface for the second metal amalgam.

[0080] Clause 12. The method of any one of clauses 1 to 7, wherein the method includes defining a first stencil area along the first thermal transfer surface for the first metal amalgam by: applying first and second strips of tape to the first thermal transfer surface such that the first and second strips of tape are generally parallel with each other and define a desired area for the first metal amalgam along the first thermal transfer surface, whereby the distance separating the first strip of tape from the second strip of tape defines a width of the first stencil area for the first metal amalgam; and applying third and fourth strips of tape to the first thermal transfer surface such that the third and fourth strips of tape are generally parallel with each and generally perpendicular to the first and second strips of tape, whereby the distance separating the third strip of tape from the fourth strip of tape defines a length of the first stencil area for the first metal amalgam, and whereby the thickness of the strips of tape defines a thickness / height of the first stencil area for the first metal amalgam.

[0081] Clause 13. The method of clause 12, wherein the method includes defining a second stencil area along the second thermal transfer surface for the second metal amalgam by: applying fifth and sixth strips of tape to the second thermal transfer surface such that the fifth and sixth strips of tape are generally parallel with each other and define a desired area for the second metal amalgam along the second thermal transfer surface, whereby the distance separating the fifth strip of tape from the sixth strip of tape defines a width of the second stencil area for the second metal amalgam; and applying seventh and eighth strips of tape to the second thermal transfer surface such that the seventh and eighth strips of tape are generally parallel with each and generally perpendicular to the fifth and sixth strips of tape, whereby the distance separating the seventh strip of tape from the eighth strip of tape defines a length of the second stencil area for the second metalDocket No. 9062D-000622-WO-POAamalgam, and whereby the thickness of the strips of tape defines a thickness / height of the second stencil area for the second metal amalgam.

[0082] Clause 14. The method of any one of clauses 1 to 7, wherein the method includes defining a first stencil area along the first thermal transfer surface for the first metal amalgam by: applying first and second pieces of material to the first thermal transfer surface such that the first and second pieces of material are generally parallel with each other and define a desired area for the first metal amalgam along the first thermal transfer surface, whereby the distance separating the first piece of material from the second piece of material defines a width of the first stencil area for the first metal amalgam; and applying third and fourth pieces of material to the first thermal transfer surface such that the third and fourth pieces of material are generally parallel with each and generally perpendicular to the first and second pieces of material, whereby the distance separating the third piece of material from the fourth piece of material defines a length of the first stencil area for the first metal amalgam, and whereby the thickness of the pieces of material defines a thickness / height of the first stencil area for the first metal amalgam.

[0083] Clause 15. The method of clause 14, wherein the method includes defining the second stencil area along the second thermal transfer surface for the second metal amalgam by: applying fifth and sixth pieces of material to the second thermal transfer surface such that the fifth and sixth pieces of material are generally parallel with each other and define a desired area for the second metal amalgam along the second thermal transfer surface, whereby the distance separating the fifth piece of material from the sixth piece of material defines a width of the second stencil area for the second metal amalgam; and applying seventh and eighth pieces of material to the second thermal transfer surface such that the seventh and eighth pieces of material are generally parallel with each other and generally perpendicular to the fifth and sixth pieces of material, whereby the distance separating the seventh piece of material from the eighth piece of material defines a length of the second stencil area for the second metal amalgam, and whereby the thickness of the pieces of material defines a thickness / height of the second stencil area for the second metal amalgam.

[0084] Clause 16. The method of any one of clauses 1 to 15, wherein the method includes: defining a first stencil area along the first thermal transfer surface for theDocket No. 9062D-000622-WO-POAfirst metal amalgam that is rectangular and / or non-rectangular to correspond to a component footprint; and / or defining a second stencil area along the second thermal transfer surface for the second metal amalgam that is rectangular and / or non-rectangular to correspond to a component footprint.

[0085] Clause 17. The method of any one of clauses 1 to 16, wherein the method includes assembling the thermal joint by bringing the first and second transfer surfaces together with the stenciled first and second metal amalgams therebetween such that the first and second metal amalgams do not leach outside the first and second stenciled areas under assembly pressure.

[0086] Clause 18. The method of clause 1, wherein the method of applying the first and second metal amalgams to the respective first and thermal transfer surfaces comprises: screen printing the first metal amalgam onto the first thermal transfer surface; and screen printing the second metal amalgam onto the second thermal transfer surface.

[0087] Clause 19. The method of any one of clauses 1 to 18, wherein: the first metal amalgam on the first thermal transfer surface has a bond line thickness of less than 100 micrometers; and / or the second metal amalgam on the second thermal transfer surface has a bond line thickness of less than 100 micrometers.

[0088] Clause 20. The method of any one of clauses 1 to 19, wherein: the first metal amalgam on the first thermal transfer surface has an initial application thickness of 25 micrometers or less; and / or the second metal amalgam on the second thermal transfer surface has an initial application thickness of 25 micrometers or less.

[0089] Clause 21. The method of any one of clauses 1 to 20, wherein the first and second metal amalgams comprise the same metal amalgam or different metal amalgams.

[0090] Clause 22. The method of any one of clauses 1 to 21, wherein either or both of the first and second metal amalgams comprises a gallium-based liquid metal.

[0091] Clause 23. The method of any one of clauses 1 to 22, wherein either or both of the first and second metal amalgams comprises a liquid metal filled with metal filler particles.

[0092] Clause 24. The method of any one of clauses 1 to 23, wherein either or both of the first and second metal amalgams consists of only metal(s).Docket No. 9062D-000622-WO-POA

[0093] Clause 25. The method of any one of clauses 1 to 24, wherein either or both of the first and second metal amalgams comprises gallium, indium, tin, nickel, and copper.

[0094] Clause 26. The method of any one of clauses 1 to 25, wherein either or both of the first and second metal amalgams comprises gallium-indium-tin liquid metal alloy including nickel particles and copper particles.

[0095] Clause 27. The method of any one of clauses 1 to 26, wherein either or both of the first and second metal amalgams comprises nickel particles and copper particles with a ratio of the nickel to the copper within a range from about 1 : 1 to about 5 : 1 by weight percent (wt%) and / or by volume percent (vol%).

[0096] Clause 28. The method of any one of clauses 1 to 27, wherein either or both of the first and second metal amalgams comprises nickel particles and copper particles with about a 2: 1 ratio of nickel to copper by weight percent (wt%) and / or by volume percent (vol%).

[0097] Clause 29. The method of any one of clauses 1 to 28, wherein either or both of the first and second metal amalgams comprises about 1 percent to about 10 percent of nickel and copper particles.

[0098] Clause 30. The method of any one of clauses 1 to 29, wherein the method includes using the first and second metal amalgams to establish a thermal path through which heat is flowable from the first thermal transfer surface to the first metal amalgam, from the first metal amalgam to the second metal amalgam, and from the second metal amalgam to the second thermal transfer surface.

[0099] Clause 31. The method of any one of clauses 1 to 30, wherein the first and second metal amalgams are configured such that, upon assembly of the joint, the first and second metal amalgams provide robust wetting and surface coverage on both the respective first and second transfer surfaces and reduce total thermal resistance by at least about three times or more relative to an otherwise identical single sided application as measured by ASTM D5470 across a range of applied pressure.

[0100] Clause 32. The method of any one of clauses 1 to 31, wherein thermal resistance measured per ASTM D5470 at a pressure between 5 to 50 psi is at least aboutDocket No. 9062D-000622-WO-POAthree times lower than an otherwise identical joint formed by single sided application of the same metal amalgam.

[0101] Clause 33. The method of any one of clauses 1 to 32, wherein at least one stencil height is defined by stacked liners to set a target bond line thickness.

[0102] Clause 34. The method of any one of clauses 1 to 33, wherein the first and / or second metal amalgam consists essentially of metals selected from gallium, indium, tin, nickel, copper.

[0103] Clause 35. The method of any one of clauses 1 to 34, wherein the first and / or second metal amalgam further comprises non-refractory filler particles.

[0104] Clause 36. The method of any one of clauses 1 to 35, wherein the first and / or second stencil areas are non-coextensive such that the first stenciled layer overlaps the second stenciled layer in projection by 50-100% of the smaller stenciled layer’s area.

[0105] Clause 37. A system configured to automatically perform the method of any one of clauses to 36, the system comprising: a stencil applicator to place and remove a stencil or stencil liner on a thermal transfer surface; a dispenser to deposit a measured droplet of a liquid metal amalgam into the stencil area; and a spreading device comprising at least one of a blade, squeegee, edge, or roller to spread the metal amalgam to the stencil height, wherein the system is operable to produce a substantially uniform layer within the stencil area and to remove excess material with the stencil upon stencil removal.

[0106] Clause 38. A thermal interface material assembly for conducting heat from a heat source to a heat dissipation component in an electronic device, the assembly comprising: a first stenciled layer of a first metal amalgam on a first thermal transfer surface; and a second stenciled layer of a first metal amalgam on a second thermal transfer surface; wherein the first stenciled layer of the first metal amalgam and the second stenciled layer of the second metal amalgam are configured, upon assembly, to form a thermal path between the first and second thermal transfer surfaces with reduced thermal resistance relative to single sided application and to maintain coverage within a defined footprint during assembly.

[0107] Clause 39. The assembly of clause 38, wherein the first and second metal amalgams comprises gallium indium tin, nickel particles, and copper particles with a ratio of the nickel to the copper within a range from about 1:1 to about 5:1 by weightDocket No. 9062D-000622-WO-POApercent (wt%) and / or by volume percent (vol%) and with about 1 percent to about 10 percent total nickel and copper particle loading.

[0108] Clause 40. The assembly of clause 38 or 39, wherein at least one of the first stenciled layer of the first metal amalgam and the second stenciled layer of the second metal amalgam has a bond line thickness of less than 100 micrometers and an initial application thickness of 25 micrometers or less.

[0109] Clause 41. The assembly of clause 38, 39, or 40, wherein the defined footprint is formed by tape based or PET stencils removed after spreading of the first and second metal amalgams such that excess metal amalgam above the stencil heights is lifted off with the stencils to leave substantially uniform thicknesses of the first stenciled layer of the first metal amalgam and the second stenciled layer of the second metal amalgam.

[0110] Clause 42. The assembly of any one of clauses 38 to 41, wherein: the first stenciled layer of the first metal amalgam is rectangular having a length to width ratio of 1 : 1 to 4: 1 ; and / or the second stenciled layer of the second metal amalgam is rectangular having a length to width ratio of 1 : 1 to 4: 1.

[0111] Clause 43. The assembly of any one of clauses 38 to 42, wherein the contact area remains within ±10% of the stenciled footprint after assembly at an applied pressure up to 50 psi.

[0112] Clause 44. An electronic device comprising: a heat source defining a first thermal transfer surface; a heat dissipation component defining a second thermal transfer surface; and first and second stenciled metal amalgam layers respectively on the first and second thermal transfer surfaces; wherein heat is conducted from the heat source to the heat dissipation component through the first and second stenciled metal amalgam layers during operation, and the first and second stenciled metal amalgam layers exhibit reduced thermal resistance relative to single sided application.

[0113] Clause 45. The electronic device of clause 44, wherein: the heat dissipation component comprises a heat sink, heat spreader, heat pipe, vapor chamber, exterior case, housing, or chassis; and / or the heat source comprises an integrated circuit or a component of a solid state drive, and / or the device further includes a board level shield thermally coupled via at least one of the stenciled layers.Docket No. 9062D-000622-WO-POA

[0114] Clause 46. The electronic device of clause 44 or 45, wherein the first and second stenciled metal amalgam layers withstand uneven lidding forces during assembly without leaching beyond the stencil boundaries.

[0115] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, electronic devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms, and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known electronic device structures, and well-known technologies are not described in detail. In addition, advantages and improvements that may be achieved with one or more exemplary embodiments of the present disclosure are provided for purpose of illustration only and do not limit the scope of the present disclosure, as exemplary embodiments disclosed herein may provide all or none of the above mentioned advantages and improvements and still fall within the scope of the present disclosure.

[0116] Specific dimensions, specific materials, and / or specific shapes disclosed herein are example in nature and do not limit the scope of the present disclosure. The disclosure herein of particular values and particular ranges of values for given parameters are not exclusive of other values and ranges of values that may be useful in one or more of the examples disclosed herein. Moreover, it is envisioned that any two particular values for a specific parameter stated herein may define the endpoints of a range of values that may be suitable for the given parameter (i.e., the disclosure of a first value and a second value for a given parameter can be interpreted as disclosing that any value between the first and second values could also be employed for the given parameter). For example, if Parameter X is exemplified herein to have value A and also exemplified to have value Z, it is envisioned that parameter X may have a range of values from about A to about Z. Similarly, it is envisioned that disclosure of two or more ranges of values for a parameter (whether such ranges are nested, overlapping or distinct) subsume all possible combination of ranges for the value that might be claimed using endpoints of the disclosed ranges. For example,Docket No. 9062D-000622-WO-POAif parameter X is exemplified herein to have values in the range of 1 - 10, or 2 - 9, or 3 -8, it is also envisioned that Parameter X may have other ranges of values including 1 - 9, 1 - 8, 1 - 3, 1 - 2, 2 - 10, 2 - 8, 2 - 3, 3 - 10, and 3 - 9.

[0117] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore 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 necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0118] When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected 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 engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0119] The term “about” when applied to values indicates that the calculation or the measurement allows some slight imprecision in the value (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If, for some reason, the imprecision provided by “about” is not otherwise understood in the art with this ordinary meaning, then “about” as used herein indicates at least variations that may arise from ordinary methods of measuring or using such parameters. For example, the terms “generally,” “about,” and “substantially,” may be used herein to mean withinDocket No. 9062D-000622-WO-POAmanufacturing tolerances. Or, for example, the term “about” as used herein when modifying a quantity of an ingredient or reactant of the invention or employed refers to variation in the numerical quantity that can happen through typical measuring and handling procedures used, for example, when making concentrates or solutions in the real world through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients employed to make the compositions or carry out the methods; and the like. The term “about” also encompasses amounts that differ due to different equilibrium conditions for a composition resulting from a particular initial mixture. Whether or not modified by the term “about,” the claims include equivalents to the quantities.

[0120] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0121] Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different 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 then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The electronic device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.Docket No. 9062D-000622-WO-POA

[0122] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements, intended or stated uses, or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

Docket No. 9062D-000622-WO-POACLAIMSWhat is claimed is:

1. A method comprising applying first and second metal amalgams onto respective first and second thermal transfer surfaces for use as thermal interface materials in a thermal joint, wherein:applying the first metal amalgam onto the first thermal transfer surface includes stenciling and / or screen printing the first metal amalgam onto the first thermal transfer surface; andapplying the second metal amalgam onto the second thermal transfer surface includes stenciling and / or screen printing the second metal amalgam onto the second thermal transfer surface.

2. The method of claim 1, wherein applying the first metal amalgam onto the first thermal transfer surface includes:using a first stencil to define a first stencil area along the first thermal transfer surface for the first metal amalgam; andapplying the first metal amalgam within the first stencil area defined along the first thermal transfer surface.

3. The method of claim 2, wherein applying the first metal amalgam onto the first thermal transfer surface includes:spreading the first metal amalgam across the first stencil area defined along the first thermal transfer surface;moving a blade, squeegee, or other edge across an upper surface of the first metal amalgam relative to the first stencil area to thereby generate a relatively uniform layer of the first metal amalgam within the first stencil area defined along the first thermal transfer surface; andremoving the first stencil from the first thermal transfer surface such that excess first metal amalgam material that exceeded the gap, thickness, or height established by the first stencil is removed as the excess metal amalgam remains on the first stencil as the firstDocket No. 9062D-000622-WO-POAstencil is removed and such that the relatively uniform layer of the first metal amalgam remains on the first thermal transfer surface.

4. The method of claim 2 or 3, wherein:the first metal amalgam comprises a first liquid metal; andapplying the first metal amalgam onto the first thermal transfer surface includes:dispensing a droplet of the first liquid metal within the first stencil area defined along the first thermal transfer surface; andspreading the droplet of the first liquid metal within the first stencil area defined along the first thermal transfer surface.

5. The method of any preceding claim, wherein applying the second metal amalgam onto the second thermal transfer surface includes:using a second stencil to define a second stencil area along the second thermal transfer surface for the second metal amalgam; andapplying the second metal amalgam within the second stencil area defined along the second thermal transfer surface.

6. The method of claim 5, wherein applying the second metal amalgam onto the second thermal transfer surface includes:spreading the second metal amalgam across the second stencil area defined along the second thermal transfer surface;moving a blade, squeegee, or other edge across an upper surface of the second metal amalgam relative to the second stencil area to thereby generate a relatively uniform layer of the second metal amalgam within the second stencil area defined along the second thermal transfer surface; andremoving the second stencil from the second thermal transfer surface such that excess second metal amalgam material that exceeded the gap, thickness, or height established by the second stencil is removed as the excess metal amalgam remains on the second stencil as the second stencil is removed and such that the relatively uniform layer of the second metal amalgam remains on the second thermal transfer surface.Docket No. 9062D-000622-WO-PQA7. The method of claim 6, wherein:the second metal amalgam comprises a second liquid metal; andapplying the second metal amalgam onto the second thermal transfer surface includes:dispensing a droplet of the second liquid metal within the second stencil area defined along the second thermal transfer surface; andspreading the droplet of the second liquid metal within the second stencil area defined along the second thermal transfer surface.

8. The method of any one of the preceding claims, wherein the method includes:using tape to define a first stencil area along the first thermal transfer surface for the first metal amalgam; andusing tape to define a second stencil area along the second thermal transfer surface for the second metal amalgam.

9. The method of any one of claims 1 to 7, wherein the method includes: using KAPTON® tape to define a first stencil area along the first thermal transfer surface for the first metal amalgam; andusing KAPTON® tape to define a second stencil area along the second thermal transfer surface for the second metal amalgam.

10. The method of any one of claims 1 to 7, wherein the method includes: using polyimide film with silicone adhesive to define a first stencil area along the first thermal transfer surface for the first metal amalgam; andusing polyimide film with silicone adhesive to define a second stencil area along the second thermal transfer surface for the second metal amalgam.

11. The method of any one of claims 1 to 7, wherein the method includes:Docket No. 9062D-000622-WO-POAusing a first polyethylene terephthalate (PET) cut out stencil without adhesive to define a first stencil area along the first thermal transfer surface for the first metal amalgam; andusing a second polyethylene terephthalate (PET) cut out stencil without adhesive to define a second stencil area along the second thermal transfer surface for the second metal amalgam.

12. The method of any one of claims 1 to 7, wherein the method includes defining a first stencil area along the first thermal transfer surface for the first metal amalgam by:applying first and second strips of tape to the first thermal transfer surface such that the first and second strips of tape are generally parallel with each other and define a desired area for the first metal amalgam along the first thermal transfer surface, whereby the distance separating the first strip of tape from the second strip of tape defines a width of the first stencil area for the first metal amalgam; andapplying third and fourth strips of tape to the first thermal transfer surface such that the third and fourth strips of tape are generally parallel with each and generally perpendicular to the first and second strips of tape, whereby the distance separating the third strip of tape from the fourth strip of tape defines a length of the first stencil area for the first metal amalgam, and whereby the thickness of the strips of tape defines a thickness / height of the first stencil area for the first metal amalgam.

13. The method of claim 12, wherein the method includes defining a second stencil area along the second thermal transfer surface for the second metal amalgam by:applying fifth and sixth strips of tape to the second thermal transfer surface such that the fifth and sixth strips of tape are generally parallel with each other and define a desired area for the second metal amalgam along the second thermal transfer surface, whereby the distance separating the fifth strip of tape from the sixth strip of tape defines a width of the second stencil area for the second metal amalgam; andapplying seventh and eighth strips of tape to the second thermal transfer surface such that the seventh and eighth strips of tape are generally parallel with each and generallyDocket No. 9062D-000622-WO-POAperpendicular to the fifth and sixth strips of tape, whereby the distance separating the seventh strip of tape from the eighth strip of tape defines a length of the second stencil area for the second metal amalgam, and whereby the thickness of the strips of tape defines a thickness / height of the second stencil area for the second metal amalgam.

14. The method of any one of claims 1 to 7, wherein the method includes defining a first stencil area along the first thermal transfer surface for the first metal amalgam by:applying first and second pieces of material to the first thermal transfer surface such that the first and second pieces of material are generally parallel with each other and define a desired area for the first metal amalgam along the first thermal transfer surface, whereby the distance separating the first piece of material from the second piece of material defines a width of the first stencil area for the first metal amalgam; andapplying third and fourth pieces of material to the first thermal transfer surface such that the third and fourth pieces of material are generally parallel with each and generally perpendicular to the first and second pieces of material, whereby the distance separating the third piece of material from the fourth piece of material defines a length of the first stencil area for the first metal amalgam, and whereby the thickness of the pieces of material defines a thickness / height of the first stencil area for the first metal amalgam.

15. The method of claim 14, wherein the method includes defining the second stencil area along the second thermal transfer surface for the second metal amalgam by:applying fifth and sixth pieces of material to the second thermal transfer surface such that the fifth and sixth pieces of material are generally parallel with each other and define a desired area for the second metal amalgam along the second thermal transfer surface, whereby the distance separating the fifth piece of material from the sixth piece of material defines a width of the second stencil area for the second metal amalgam; and applying seventh and eighth pieces of material to the second thermal transfer surface such that the seventh and eighth pieces of material are generally parallel with each other and generally perpendicular to the fifth and sixth pieces of material, whereby the distance separating the seventh piece of material from the eighth piece of material definesDocket No. 9062D-000622-WO-POAa length of the second stencil area for the second metal amalgam, and whereby the thickness of the pieces of material defines a thickness / height of the second stencil area for the second metal amalgam.

16. The method of any one of the preceding claims, wherein the method includes:defining a first stencil area along the first thermal transfer surface for the first metal amalgam that is rectangular and / or non-rectangular to correspond to a component footprint; and / ordefining a second stencil area along the second thermal transfer surface for the second metal amalgam that is rectangular and / or non-rectangular to correspond to a component footprint.

17. The method of any one of the preceding claims, wherein the method includes assembling the thermal joint by bringing the first and second transfer surfaces together with the stenciled first and second metal amalgams therebetween such that the first and second metal amalgams do not leach outside the first and second stenciled areas under assembly pressure.

18. The method of claim 1, wherein the method of applying the first and second metal amalgams to the respective first and thermal transfer surfaces comprises:screen printing the first metal amalgam onto the first thermal transfer surface; and screen printing the second metal amalgam onto the second thermal transfer surface.

19. The method of any one of the preceding claims, wherein:the first metal amalgam on the first thermal transfer surface has a bond line thickness of less than 100 micrometers; and / orthe second metal amalgam on the second thermal transfer surface has a bond line thickness of less than 100 micrometers.

20. The method of any one of the preceding claims, wherein:Docket No. 9062D-000622-WO-POAthe first metal amalgam on the first thermal transfer surface has an initial application thickness of 25 micrometers or less; and / orthe second metal amalgam on the second thermal transfer surface has an initial application thickness of 25 micrometers or less.

21. The method of any one of the preceding claims, wherein the first and second metal amalgams comprise the same metal amalgam or different metal amalgams.

22. The method of any one of the preceding claims, wherein either or both of the first and second metal amalgams comprises a gallium-based liquid metal.

23. The method of any one of the preceding claims, wherein either or both of the first and second metal amalgams comprises a liquid metal filled with metal filler particles.

24. The method of any one of the preceding claims, wherein either or both of the first and second metal amalgams consists of only metal(s).

25. The method of any one of the preceding claims, wherein either or both of the first and second metal amalgams comprises gallium, indium, tin, nickel, and copper.

26. The method of any one of the preceding claims, wherein either or both of the first and second metal amalgams comprises gallium-indium-tin liquid metal alloy including nickel particles and copper particles.

27. The method of any one of the preceding claims, wherein either or both of the first and second metal amalgams comprises nickel particles and copper particles with a ratio of the nickel to the copper within a range from about 1:1 to about 5:1 by weight percent (wt%) and / or by volume percent (vol%).Docket No. 9062D-000622-WO-POA28. The method of any one of the preceding claims, wherein either or both of the first and second metal amalgams comprises nickel particles and copper particles with about a 2:1 ratio of nickel to copper by weight percent (wt%) and / or by volume percent (vol%).

29. The method of any one of the preceding claims, wherein either or both of the first and second metal amalgams comprises about 1 percent to about 10 percent of nickel and copper particles.

30. The method of any one of the preceding claims, wherein the method includes using the first and second metal amalgams to establish a thermal path through which heat is flowable from the first thermal transfer surface to the first metal amalgam, from the first metal amalgam to the second metal amalgam, and from the second metal amalgam to the second thermal transfer surface.

31. The method of any one of the preceding claims, wherein the first and second metal amalgams are configured such that, upon assembly of the joint, the first and second metal amalgams provide robust wetting and surface coverage on both the respective first and second transfer surfaces and reduce total thermal resistance by at least about three times or more relative to an otherwise identical single-sided application as measured by ASTM D5470 across a range of applied pressure.Docket No. 9062D-000622-WO-POA32. A thermal interface material assembly for conducting heat from a heat source to a heat dissipation component in an electronic device, the assembly comprising:a first stenciled layer of a first metal amalgam on a first thermal transfer surface; anda second stenciled layer of a first metal amalgam on a second thermal transfer surface;wherein the first stenciled layer of the first metal amalgam and the second stenciled layer of the second metal amalgam are configured, upon assembly, to form a thermal path between the first and second thermal transfer surfaces with reduced thermal resistance relative to single-sided application and to maintain coverage within a defined footprint during assembly.

33. The assembly of claim 32, wherein the first and second metal amalgams comprises gallium-indium-tin, nickel particles, and copper particles with a ratio of the nickel to the copper within a range from about 1:1 to about 5:1 by weight percent (wt%) and / or by volume percent (vol%) and with about 1 percent to about 10 percent total nickel and copper particle loading.

34. The assembly of claim 32 or 33, wherein at least one of the first stenciled layer of the first metal amalgam and the second stenciled layer of the second metal amalgam has a bond line thickness of less than 100 micrometers and an initial application thickness of 25 micrometers or less.

35. The assembly of claim 32, 33, or 34, wherein the defined footprint is formed by tape-based or PET stencils removed after spreading of the first and second metal amalgams such that excess metal amalgam above the stencil heights is lifted off with the stencils to leave substantially uniform thicknesses of the first stenciled layer of the first metal amalgam and the second stenciled layer of the second metal amalgam.Docket No. 9062D-000622-WO-POA36. An electronic device comprising:a heat source defining a first thermal transfer surface;a heat dissipation component defining a second thermal transfer surface; and first and second stenciled metal amalgam layers respectively on the first and second thermal transfer surfaces;wherein heat is conducted from the heat source to the heat dissipation component through the first and second stenciled metal amalgam layers during operation, and the first and second stenciled metal amalgam layers exhibit reduced thermal resistance relative to single-sided application.

37. The electronic device of claim 36, wherein:the heat dissipation component comprises a heat sink, heat spreader, heat pipe, vapor chamber, exterior case, housing, or chassis; and / orthe heat source comprises an integrated circuit or a component of a solid-state drive, and / or the device further includes a board-level shield thermally coupled via at least one of the stenciled layers.

38. The electronic device of claim 37 or 38, wherein the first and second stenciled metal amalgam layers withstand uneven lidding forces during assembly without leaching beyond the stencil boundaries.

Images