Amalgamation preform

Abstract

The amalgamation preform comprises a nonmetal and a plurality of types of solid particles dispersed in the nonmetal, wherein the nonmetal comprises one of a liquid nonmetal and a solid nonmetal. The plurality of types of solid particles include non-reactive magnetic particles that are reactive to a magnetic field and reactive particles capable of reacting with the nonmetal under a magnetic field in order to controllably disperse at least the plurality of types of solid particles in the nonmetal.

Description

Technology Field

[0001] Cross-reference regarding related applications

[0002] This PCT application claims priority to U.S. Patent Application No. 17 / 365,811, filed July 1, 2021, which is a partial continuation of U.S. Patent Application No. 17 / 073,370, filed October 18, 2020, the full text of which is incorporated herein by reference.

[0003] Technology field

[0004] The present invention generally relates to the field of bonding and joining technology, and more particularly to an amalgamated preform and a method for manufacturing / using an amalgamated preform. Background Technology

[0005] Classical bonding and joining techniques using soldering or brazing require the addition of thermal energy and flux. Both soldering and brazing require thermal energy to melt and flow the bonding or filling materials, bring them into contact with surfaces, and create a bond. Flux is necessary to remove oxides and contaminants from the mating surfaces and filling materials, and to protect the filling materials from environmental oxidation. Generally, oxidation of filling materials having an oxide layer on them must be prevented, as it adversely affects the formation of the joint.

[0006] One aspect of the present invention provides an amalgamation preform. The amalgamation preform comprises a base metal and a plurality of types of solid particles dispersed in the base metal, wherein the base metal comprises one of a liquid base metal and a solid base metal. The plurality of types of solid particles comprises at least the following: non-reactive magnetic particles that are reactive to a magnetic field to controllably disperse the plurality of types of solid particles in the base metal, and reactive particles capable of reacting with the base metal under a magnetic field.

[0007] Another aspect of the present invention provides a method for manufacturing an amalgamation preform. A particle-liquid mixture containing a plurality of types of solid particles and a liquid nonmetal is provided. The plurality of types of solid particles include at least reactive particles capable of reacting with the nonmetal, and non-reactive magnetic particles. A magnetic field is applied to the particle-liquid mixture to magnetically disperse the plurality of types of solid particles in the liquid nonmetal, thereby forming a particle-liquid dispersion without substantially inducing a reaction between the reactive particles and the liquid nonmetal. A Play-Doh-type amalgamation preform is manufactured based on the particle-liquid dispersion without solidifying the liquid nonmetal.

[0008] Another aspect of the present invention provides a method for manufacturing an amalgamation preform. A particle-liquid mixture containing a plurality of types of solid particles and a liquid nonmetal is provided. The plurality of types of solid particles include at least reactive particles capable of reacting with the nonmetal, and non-reactive magnetic particles. A magnetic field is applied to the particle-liquid mixture to magnetically disperse the plurality of types of solid particles in the liquid nonmetal, thereby forming a particle-liquid dispersion without substantially inducing a reaction between the reactive particles and the liquid nonmetal. The liquid nonmetal is solidified to disperse the plurality of types of solid particles in the solidified nonmetal without substantially inducing a reaction between the reactive particles and the solid nonmetal. A solid amalgamation preform comprising the plurality of types of solid particles and the solidified nonmetal is manufactured.

[0009] Another aspect of the present invention provides a method for using an amalgamation preform. A paired bonding surface is provided, and a particle-liquid mixture corresponding to the amalgamation preform is disposed between the paired bonding surfaces. The particle-liquid mixture contains a plurality of types of solid particles and a nonmetal in liquid form, and the plurality of types of solid particles include at least reactive particles and non-reactive magnetic particles. A first magnetic field is applied to the particle-liquid mixture to magnetically disperse the plurality of types of solid particles in the liquid nonmetal to form a particle-liquid dispersion; and a second magnetic field is applied to cure the particle-liquid dispersion to allow a reaction between the reactive particles and the nonmetal.

[0010] Another aspect of the present invention provides a method for using an amalgamation preform. A paired bonding surface is provided, and the amalgamation preform is disposed between the paired bonding surfaces. The amalgamation preform contains a plurality of types of solid particles and a nonmetal, and the plurality of types of solid particles include at least reactive particles and non-reactive magnetic particles. The amalgamation preform is heated to a temperature above the low melting temperature of the nonmetal to provide a particle-liquid mixture containing a plurality of types of solid particles in a liquid nonmetal. During heating, a magnetic field is applied to magnetically disperse the plurality of types of solid particles in the liquid nonmetal and to allow a reaction between the reactive particles and the nonmetal.

[0011] Other aspects of the present invention may be understood by those skilled in the art in light of the description of the invention, the claims, and the drawings. Brief explanation of the drawing

[0012] The following drawings are merely examples for illustrative purposes according to various disclosed embodiments and are not intended to limit the scope of the invention. FIG. 1a illustrates an exemplary method for manufacturing an amalgamated preform according to various embodiments of the present invention. FIG. 1b illustrates another exemplary method for manufacturing an amalgamated preform according to various embodiments of the present invention. FIG. 2 illustrates an exemplary particle-liquid mixture in a container according to various embodiments of the present invention. FIG. 3 illustrates an exemplary apparatus including a magnetic processing device for processing a particle-liquid mixture according to various embodiments of the present invention. FIGS. 4 through 7 illustrate the controllable application of a magnetic field to a particle-liquid mixture in a container according to various embodiments of the present invention. FIG. 8 illustrates an exemplary solidified particle-liquid dispersion in a container according to various embodiments of the present invention. FIG. 9a illustrates an exemplary method for using an amalgamated preform according to various embodiments of the present invention. FIG. 9b illustrates another exemplary method for using an amalgamated preform according to various embodiments of the present invention. FIG. 10 illustrates an exemplary apparatus including a magnetic processing device for processing a solid amalgamated preform according to various embodiments of the present invention. FIGS. 11 to 15 illustrate exemplary mixing and dispersion of liquefied amalgamated preforms under the application of a controlled magnetic field according to various embodiments of the present invention. FIG. 16 illustrates an exemplary solid alloy corresponding to an amalgamated preform according to various embodiments of the present invention. Specific details for implementing the invention

[0013] We will now refer in detail to exemplary embodiments of the present invention illustrated in the attached drawings. Where possible, the same reference numerals will be used throughout the drawings to indicate identical or similar parts.

[0014] FIGS. 1a-1b illustrates an exemplary method for manufacturing an amalgamated preform according to various embodiments of the present invention.

[0015] In Figure 102 of FIG. 1a-1b, a particle-liquid mixture containing a plurality of types of solid particles and a liquid nonmetal (i.e., a nonmetal in liquid form) is provided, for example, in a container.

[0016] In one embodiment, to provide a particle-liquid mixture, a plurality of types of solid particles may be mixed with a nonmetal in solid form (e.g., solid particles of a nonmetal or nonmetal particles) within a container. The nonmetal particles and / or the plurality of types of solid particles may be in the form of metal powder, pellets, wires, fibers, ingots, or a combination thereof. The nonmetal particles and the plurality of types of solid particles may be mixed, for example, at room temperature. Subsequently, the nonmetal particles may be melted into liquid form together with the mixed plurality of types of solid particles, for example, by any suitable heating process, to form a particle-liquid mixture. For example, the nonmetal particles may be melted by convection or induction heating caused by the application of a magnetic field. The magnetic field may be controlled / regulated to heat the nonmetal without destroying the structure of other particles in the mixture.

[0017] Alternatively, to form a particle-liquid mixture, non-metal particles can be melted to form a liquid non-metal within a container, and then multiple types of solid particles can be injected into the liquid non-metal to form the particle-liquid mixture.

[0018] The nonmetal may include metals and / or metal alloys with low melting points. For example, the nonmetal may have a melting point of about 200°C or less. The nonmetal may include, for example, Ga, In, Sn, Bi, Pb, Cd, Hg, Rb, Zn, Bi, or combinations / alloys thereof. In certain embodiments, the nonmetal may include Ga, GaInSn, and / or InSnBi.

[0019] In the particle-liquid mixture, the ratio of liquid nonmetal to multiple types of solid particles is in the range of about 4:1 to about 1:4 by weight, for example, in the range of 4:1 to 1:2, and the multiple types of solid particles are present in an amount that is easy to handle in the liquid state but has sufficient mechanical properties. The multiple types of solid particles may have an average size in the range of about 100 nm to about 100 µm.

[0020] Various types of solid particles may be mixed with nonmetals. For example, multiple types of solid particles may include reactive particles, non-reactive magnetic particles, and / or any suitable additives to provide desirable characteristics to the particle-liquid mixture and / or the subsequently formed amalgamation preform.

[0021] As used herein, the terms “reactive” and “non-reactive” are relative terms indicating the degree of reactivity or reactivity between solid particles and nonmetals. For example, under certain conditions, “reactive” particles may react with a nonmetal in liquid form (i.e., liquid nonmetal) for the bonding / hardening / alloying of the nonmetal and solid particles corresponding to an amalgamation preform. “Non-reactive” particles may refer to solid particles that cannot bond / harden / alloy with a liquid nonmetal under the same specific conditions. For example, solid particles may be considered non-reactive when they “react” with a liquid nonmetal, for instance, after a certain period, at significantly slow kinetics where bonding / hardening / alloying is impossible. As an extreme example, materials that are completely non-reactive with a liquid nonmetal may include ceramics or covalently bonded organic materials.

[0022] The reactive particles can react with nonmetals. The reactive particles may comprise at least a reactive metallic material. The reactive metallic material may comprise Fe, Ni, Cu, Ag, Au, In, Cu, Sn, Bi, Zn, Ti, V, Cr, Mo, Nb, Zr, Hf, Pt, Ir, and / or any combination thereof (e.g., alloys).

[0023] The reactive particles may have an average size in the range of about 100 nm to about 50 µm, for example, about 100 nm to about 25 µm. For desirable reactivity, the reactive particles may be selected to be neither too large nor too small. Reactive particles that are too large may take too long to react with the nonmetal, whereas particles that are too small may react too quickly. The inventors have found that when the reactive particles have a size of less than 100 nm, the reaction between the reactive particles and the nonmetal is too fast to be desirable for alloying.

[0024] Reactive particles may be magnetic and / or non-magnetic. For example, reactive magnetic particles may comprise Fi, Ni, and / or alloys thereof. Reactive non-magnetic particles may comprise Cu, Ag, Au, In, Cu, Sn, Bi, Zn, Ti, V, Cr, Mo, Nb, Zr, Hf, Pt, Ir, or any combination thereof (e.g., alloys). In addition to being able to react with non-metals, in some embodiments, reactive magnetic particles may be able to respond to magnetic signals.

[0025] Reactive particles, whether magnetic or non-magnetic, may comprise a core-shell structure. The core-shell structure may comprise a core material and a shell material that is distinct from the core material and at least partially surrounds the core material. The core material may have a faster reaction rate with nonmetals than the shell material, and vice versa.

[0026] In some embodiments, the core-shell structure of the reactive particle may comprise an oxide shell material that at least partially coats the reactive metal material as the core material. The oxide shell material may comprise an oxide material of the reactive metal material. The oxide shell material may be a natural oxide material or may be intentionally formed by an oxidation reaction, such as thermal oxidation, with the reactive metal material. For example, if the reactive metal material is one or more of Fe and Ni as the core material, the shell material may be an oxide of one or more of Fe and Ni. Unlike conventional preform materials in which the oxide shell layer must be removed to form and use an amalgamation preform, the disclosed oxide shell layer is necessary to control reaction kinetics / rates to form and use an amalgamation preform.

[0027] In another embodiment, the core-shell structure of the reactive particle may include a non-oxide shell material. For example, the core-shell structure may include one or more of: a core-shell structure having a shell material comprising Cu and a core material comprising Au; a core-shell structure having a shell material comprising steel and a core material comprising Cu; a core-shell structure having a shell material comprising ZnO or TiO2 and a core material comprising Cu, Ag, Ni, or a combination thereof; and / or a core-shell structure having a shell material comprising Cu and copper oxide that at least partially covers Cu, and a core material comprising Co and a ceramic material comprising AlN, SiC, SiO2, TiO2, ZrO2, Al2O3, BeO, Si3N4, B4C, WC, and / or diamond, or a combination thereof.

[0028] In various embodiments, the core material may be formed in multiple layers, for example, by at least one material that is reactive with the base material and at least another material that provides desirable properties (e.g., providing improved mechanical strength) to the amalgamation preform subsequently formed. Optionally and additionally, the shell material may also be formed in multiple layers. For example, if the shell material contains copper to react with a nonmetal, the copper shell material may include an additional shell layer of copper oxide that at least partially covers the copper shell material.

[0029] In various embodiments, the particle-liquid mixture may be magnetically dispersed to form a particle-liquid dispersion without substantially inducing any reaction (e.g., alloying reaction) between the reactive particles and the nonmetal (e.g., as illustrated in Operation 104 of FIG. 1a-1b), which may be a homogeneous dispersion. The particle-liquid dispersion may be used to form amalgamation preforms comprising a Play-Doh type amalgamation preform (e.g., as illustrated in Operation 106 of FIG. 1a) and a solid amalgamation preform (e.g., as illustrated in Operations 108 and 109 of FIG. 1a-1b), as disclosed herein. The amalgamation preforms may then be used directly for bonding / curing / alloying or stored / transported for later / future use.

[0030] As disclosed in this specification, in one embodiment, the shell material of the reactive particle can be used to control the storage life and / or reaction rate of the formed amalgamated preform by controlling the kinetics and dissolution rate of the core material, for example.

[0031] The core-shell structure of the reactive particles can extend the storage life of the formed amalgamation preform at least further. For example, the shell material can be thick enough to largely prevent solid-state alloying between the reactive particles and the solid nonmetal, and thin enough to overcome undergoing such reactions during reflow. The shell material can have a thickness ranging from atomic layer thickness to about 100 nm. For example, the shell material can have a thickness of multiple atomic layers. The thickness of the shell material can be controlled according to the selection of the nonmetal and reactive particles, and / or the target storage life of the formed amalgamation preform.

[0032] In an exemplary amalgamation preform having reactive particles in which the core material is one or more of Fe and Ni and the shell material is an oxide of one or more of Fe and Ni, the rate of dissolution or penetration by an exemplary nonmetallic Ga material through the shell material depends on the thickness of the shell material. In the example for forming a Play-Doh-type amalgamation preform for rapid use, the shell material may be relatively thin for rapid setting and may be increased in thickness to extend the handling and setting time of the material. To form a solid amalgamation preform, the shell material may be sufficiently thick to prevent reaction during initial mixing and subsequent solidification (e.g., for a few minutes), and may be, for example, at least several nanometers. The rate of reaction and penetration of the liquid nonmetal through the shell material may increase with temperature, which allows for a long storage life near room temperature but can cure rapidly at processing temperatures.

[0033] According to various embodiments, in addition to controlling the shell thickness, other mechanisms can be applied to the core-shell structure of the reactive particles to control the storage life, reaction kinetics, and rate of the formed amalgamated preform.

[0034] For example, amalgamation preforms may contain reactive particles, including a shell material that reacts more slowly with the nonmetal than the core material, to provide longer preform processing times. For example, the shell material may be copper and the core material may be gold, and the nonmetal may be liquid Ga that reacts faster with gold than with copper.

[0035] Another exemplary amalgamation preform may contain reactive particles comprising a reactive shell material (e.g., Cu) and a non-reactive core material (e.g., Co, and / or ceramic materials including AlN, SiC, SiO2, TiO2, ZrO2, Al2O3, BeO, Si3N4, B4C, WC, and / or diamond). In some cases, the reactive shell material may comprise a multilayer having an oxide layer that at least partially covers the reactive shell material. In one example, the shell material may be Cu and the core material may be Co, and the shell material may further comprise copper oxide covering the copper shell material. The magnetic properties of Co may be utilized for heating, mixing, and / or wetting, while the shell material may allow for a cohesive interface and strong bonding between the bonding surface and the preform material. In another example, the shell material may be Cu and the core material may be a ceramic material such as AlN, while the shell material may additionally include copper oxide coating the copper shell material. These reactive particles can provide a slow reaction rate and an extended shelf life of the formed amalgamated preform.

[0036] In various embodiments, the shell material may be selected to be incorporated to support and reinforce the matrix / bulk of the amalgamated preform.

[0037] In an exemplary amalgamation preform, the shell material of the reactive particles may be non-reactive and / or may partially coat the inner particles of the reactive core material (e.g., as a patchy shell). When the inner particles are dissolved by the Ga liquid, the shell material remains in the performance material to provide mechanical reinforcement and form a composite. Such shell materials may include ductile materials, including steel, and the core material may be Cu. In another example, the shell material may be a brittle oxide, such as ZnO and / or TiO2, which may rupture due to a mismatch in thermal expansion with the Cu, Ag, and / or Ni metals used as the core material inside the shell material. Hard and brittle shell materials can reinforce the matrix / bulk of the amalgamation preform when processed.

[0038] In various embodiments, the shell material may be destroyed during preform processing. For example, the shell material of the reactive particles may be overcome, for instance, through the dissolution of the nonmetal due to the application of a magnetic field. For example, under the control of a magnetic field, the oxide shell material may be destroyed so that its core material Fe or Cu can interact / react with the liquid nonmetal.

[0039] Multiple types of solid particles may additionally include non-reactive magnetic particles. The non-reactive magnetic particles may not react with nonmetals, but may be reactive to magnetic signals to facilitate / drive heating, mixing, and / or wetting of the particle-liquid mixture, for example (as illustrated in work 104 in FIG. 1a-1b). For example, the non-reactive magnetic particles may include Co-containing particles, Nd-containing particles, and / or Cr-containing particles.

[0040] Non-reactive magnetic particles may have an average size in the range of about 1 µm to about 100 µm, for example, in the range of about 5 µm to about 100 µm. For example, non-reactive magnetic particles may include large magnetic particles with at least one dimension exceeding 5 µm. These large magnetic particles may include microwires, microfibers, or a combination thereof.

[0041] In some cases, large magnetic particles, e.g., microwires and / or microfibers, as solid particles may be added to facilitate the heating, mixing, and / or wetting properties of the particle-liquid mixture placed within the container or between the bonding surfaces, and / or to provide additional desirable features. The large magnetic particles may be reactive or non-reactive. For example, large (e.g., greater than about 50 µm) reactive and magnetic Fe and / or Ni particles may be added to the particle-liquid mixture to provide desirable mixing and wetting properties for dispersion and to participate at least partially in the reaction for bonding / curing.

[0042] Optionally and additionally, multiple types of solid particles may include any other particles to provide a subsequently formed amalgamation preform having desirable features / properties. For example, semiconductor particles and / or metal-doped semiconductor particles (e.g., SiC, AlN, SiO2, and / or diamond, with or without dopants) may provide improved thermal conductivity of the formed amalgamation preform by being added as additive particles, while reducing the electrical conductivity of the amalgamation preform. In some cases, additive particles may be additionally added to the particle-liquid mixture to facilitate heating, mixing, and / or wetting properties during the formation or processing of the amalgamation preform, regardless of whether they are reactive, non-reactive, magnetic, or non-magnetic.

[0043] FIG. 2 shows an exemplary particle-liquid mixture in a container according to various embodiments of the present invention. As disclosed, the particle(s) shown in FIG. 2 may be modified and / or omitted, and more particles may be included in the exemplary particle-liquid mixture.

[0044] As shown in FIG. 2, an exemplary particle-liquid mixture (220) comprises a liquid nonmetal (20A) mixed with various particles as disclosed herein, such as reactive particles (201 / 203) (e.g., including at least reactive magnetic particles (201) and reactive nonmagnetic particles (203)), non-reactive magnetic particles (206), and / or any other suitable solid additive (208).

[0045] A particle-liquid mixture (220) is contained in a container (210). The container (210) may be used for mixing, dispersion, and / or coagulation. The container (210) may be polymeric to minimize the bonding strength between the contained mixture and the inner surface of the container, and may or may not contain a filler. For example, the container (210) may include at least a plastic surface for contacting the particle-liquid mixture, made of a material including polytetrafluoroethylene (PTFE or Teflon), high-density polyethylene (HDPE), or low-density polyethylene (LDPE), which has low surface energy to prevent wetting. Of course, the container may be made of any other suitable material including metal, ceramic, or non-polymeric material, and may or may not have a plastic surface thereon.

[0046] In 104 of FIG. 1a-1b, a magnetic field is applied to a particle-liquid mixture to magnetically disperse multiple types of solid particles in a liquid nonmetal to form a particle-liquid dispersion. The magnetic field can be applied in a manner that does not induce any reaction between the solid particles and the liquid nonmetal.

[0047] As disclosed in this specification, a particle-liquid dispersion may refer to a magnetically dispersed particle-liquid mixture, wherein a plurality of types of solid particles may be controllably dispersed and, for example, substantially homogeneously dispersed in a liquid nonmetal by applying a magnetic field.

[0048] FIG. 3-7 illustrates the controllable application of a magnetic field to an exemplary particle-liquid mixture (220) in a container (210) for magnetically dispersing a plurality of types of solid particles (e.g., particles (201, 203, 206, and / or 208)) in a liquid nonmetal (20A) to form a particle-liquid dispersion.

[0049] The container illustrated in FIG. 2-7 is positioned such that it has an opening on the side and a longitudinal direction substantially perpendicular to the opening (as illustrated in FIG. 3), but the container may be positioned in any preferred manner or at any angle according to various embodiments of the present invention. Additionally, the particle-liquid mixture contained in the container may be positioned such that it has a thickness from the inner wall of the container, a thickness covering a portion of the width / diameter of the container, or a thickness covering the entire width / diameter of the container.

[0050] Referring to FIG. 3, a container (210) containing a particle-liquid mixture (220) can be placed in a magnetic field generated, for example, by a magnetic processing device (330).

[0051] In one embodiment, the magnetic processing device (330) may include a coil wound around a container (210). The shape and / or dimensions of the wire used for coil winding may be determined based on the specific application of a magnetic field. For example, the coil winding may have a uniform shape and dimensions, for example, and may be wound evenly or unevenly distributed along the longitudinal direction of the container (210).

[0052] The magnetic processing device (330) may be connected to or include a controller (not shown), such as a computer controller, to control the current and / or current change of the coil winding, thereby controlling, for example, the polarity, strength, localization, movement, orientation, rotation, spinning, etc. of the magnetic field. For example, a coil of a specific length may be selected by the controller to selectively apply a magnetic field to a portion of the particle-liquid mixture to locally disperse solid particles in the particle-liquid mixture. In another example, the magnetic field may be controlled and changed in a specific direction, for example, along the longitudinal direction of the container. In another example, the controller may control the coil winding to repeatedly provide a rotational field and / or translational field back and forth, for example, along a specific direction. In another example, the controller may control the coil winding to move the particle-liquid mixture between different locations along the inner wall of the container from one location to another, or to move the particle-liquid material out of the container without physical handling of the material.

[0053] The magnetic field can be applied in any suitable manner. Other suitable magnetic processing devices may include electromagnets and / or physical permanent magnets. For example, a magnetic field can be provided by performing electronic control of an electromagnet and / or control of a moving physical permanent magnet in close proximity to a particle-liquid mixture contained in a container.

[0054] In some embodiments, the container of FIG. 3-7 may be placed inside a magnetic processing device.

[0055] In one embodiment, for example as illustrated in FIG. 4, a magnetic field may be applied and aligned so that solid particles within a liquid nonmetal are pulled and moved toward the interface with the container. Meanwhile, the magnetic field may be used to heat and maintain the nonmetal in liquid form without applying additional heating for the reaction.

[0056] The magnetic field can be moved at various angles to drag solid particles across the surface of the container, and can move along any suitable shape or path of movement, for example, through the cross-section of the particle-liquid mixture, as shown in FIG. 5. Solid particles dragged from the surface of the container can allow wetting by scraping, removing, and / or destroying the natural oxide layer formed on the outermost layer (505) of the particle-liquid mixture at the mixture-container interface. In some embodiments, larger particles may allow for greater force compared to the viscous force experienced in the particle-liquid mixture and may have a better chance of moving solid particles to the mixture-container interface, as shown in FIG. 6, for example. In this way, the movement of magnetic particles can be controlled to improve surface wetting and reduce voiding and gaps often generated in conventional soldering materials.

[0057] The application of a magnetic field can allow for the movement and distribution of all solid particles within a particle-liquid mixture. Often, instead of being driven by mechanical forces that compress the particles and drive out the liquid components, the initiated particle-liquid mixture / dispersion can be moved from one location to another as a slug without squeezing out the liquid components. Additionally, the magnetic field may be used to smooth the particle-liquid mixture after it has been distributed as a large "slug," as shown in FIG. 7.

[0058] Therefore, non-reactive solid particles can be used to form high-quality amalgamation preforms by driving, diffusing, mixing, and / or heating a particle-liquid mixture to form a homogeneous particle-liquid dispersion. When the amalgamation preform is processed, the non-reactive solid particles can be used to promote curing and / or strengthen the corresponding particle-liquid mixture / dispersion for bonding.

[0059] In one embodiment, a gradient static magnetic field may be used to align magnetic fibers or wires within a particle-liquid mixture to provide preferential and anisotropic properties, for example, as illustrated in FIG. 6. For example, large magnetic particles of Fe, Ni, Co, Cr, Nb, and / or their alloys may be included in the particle-liquid mixture to form an amalgamation preform or for bonding / hardening / alloying when processing the amalgamation preform. The magnetic alignment may be modified to produce various properties such as anisotropic thermal conductivity and / or mechanical strength.

[0060] Instead of conventional mechanical mixing, the disclosed magnetic mixing / dispersion can be performed under a magnetic field so that various particles are oriented, moved, and / or aligned along the entire cross-section of the particle-liquid mixture.

[0061] For example, under a dynamic magnetic field or a helical magnetic field, the movement of solid magnetic particles (reactive or non-reactive, with or without large size) can be driven through a liquid nonmetal. The mixing form can be designed to mimic, for example, an amalgamated preform in a target. The disclosed magnetic mixing / dispersion can be random or sequential and can be performed simultaneously with magnetic heating.

[0062] The disclosed magnetic mixing / dispersion may allow reactive materials / particles to be sufficiently separated to significantly increase the shelf life of the subsequently formed amalgamation preform. When the amalgamation preform is ready to be bonded, the materials separated from the amalgamation preform may be redeployed and rededispersed before being placed on the bonding surface or after contacting the bonding surface. In some cases, the materials in the amalgamation preform may be coarsely mixed into particle clumps or may contain layers of different materials.

[0063] In some embodiments, the particle-liquid mixture / dispersion may be diffused and flattened on a surface as shown in FIG. 7. The flattened particle-liquid mixture / dispersion may have a thickness of, for example, about 1 mm or less.

[0064] Referring to the operation (106) of FIG. 1a, the particle-liquid dispersion is subsequently processed, for example, by rolling, pressing, extrusion, casting, etc., to form a Play-Doh-type amalgamation preform without solidifying the liquid nonmetal. The Play-Doh-type amalgamation preform may be formed to include a bar, sheet, ingot, filament, or any suitable shape. For example, the Play-Doh-type amalgamation preform may be rolled to have a thickness ranging from about 5 μm to about 500 μm.

[0065] Subsequently, the Play-Doh type amalgamation preform can be used directly or solidified at 108 in FIG. 1a to form a solid amalgamation preform. The solid amalgamation preform may have a shape / dimension corresponding to the Play-Doh type amalgamation preform.

[0066] In 108 of FIG. 1a, the Play-Doh type amalgamation preform can be cooled, for example, by liquid cooling, Peltier cooling, or by immersion in a cooling liquid such as water or LN2. The cooling process can provide a corresponding solid amalgamation preform without substantially inducing any reaction by quenching the Play-Doh type amalgamation preform.

[0067] Alternatively, as illustrated in FIG. 1b, after forming a particle-liquid dispersion in the operation (104), the solidification process of 107 can be performed so that the solid particles are uniformly dispersed in the solidified nonmetal without substantially inducing a reaction between the solid particles, as illustrated in FIG. 8.

[0068] When solidifying a particle-liquid dispersion, for example, the entire assembly including a container and the particle-liquid dispersion contained therein may be cooled by liquid cooling, Peltier cooling, or immersion in a cooling liquid such as water. The cooling process can quench the particle-liquid dispersion without substantially inducing any reaction, for example, without destroying the shell material of the reactive core material.

[0069] Still in FIG. 1b, 109, the solidified particle-liquid dispersion can be processed to form a solid amalgamation preform by rolling, drawing, forging, stamping, milling, turning, etc. For example, the solidified particle-liquid dispersion can be rolled to have a thickness of about 25 μm to about 10 mm, or in some cases, drawn into a wire. In other cases, the solidified particle-liquid dispersion can be milled at room temperature or cold-milled into a powder formulation to form a solid amalgamation preform.

[0070] In this way, the Play-Doh type amalgamation preform manufactured in the operation (106) of FIG. 1a or the solid amalgamation preform manufactured in 108 of FIG. 1a and / or 109 of FIG. 1b may be in the form of an application and ready for use.

[0071] It should be noted that when performing the exemplary method illustrated in FIG. 1a-1b, substantially no reaction is induced between the nonmetal and the reactive particles. For example, the formed Play-Doh-type amalgamation preform may contain various types of solid particles magnetically dispersed in a liquid nonmetal, and substantially no reaction occurs between the reactive particles and the liquid nonmetal at nearly room temperature (e.g., about 25°C) or below. The formed solid amalgamation preform may contain various types of solid particles magnetically dispersed in a solid nonmetal, and substantially no reaction occurs between the reactive particles and the solid nonmetal at nearly room temperature (e.g., about 25°C) or below.

[0072] FIGS. 9a-9b illustrates an exemplary method for using an amalgamated preform according to various embodiments of the present invention.

[0073] In Figure 902 of Fig. 9a-9b, a paired bonding surface is provided.

[0074] As used herein, the terms “paired surface,” “bonding surface,” and “paired bonding surface” may be used interchangeably in the present invention. Accordingly, the term “bonding material” may refer to any material placed and processed between paired bonding surfaces for, for example, re-flow, redispersion, and bonding / hardening / alloying.

[0075] Accordingly, the binding material may comprise any amalgamation preform comprising, for example, a particle-liquid mixture (e.g., as exemplified in 102 in FIG. 1a-1b), a particle-liquid dispersion (e.g., as exemplified in 104 in FIG. 1a-1b), and / or a Play-Doh type amalgamation preform (e.g., as exemplified in 106 in FIG. 1a), and / or a solid amalgamation preform (e.g., as exemplified in 108 in FIG. 1a and 109 in FIG. 1b).

[0076] A mating bonding surface may be provided by two mating substrates. In some cases, the mating bonding surface may be opposite surfaces on one substrate. A mating bonding surface may be provided to place a particle-liquid mixture / dispersion and / or an amalgamation preform (e.g., a Play-Doh type amalgamation preform and / or a solid amalgamation preform) between them for bonding / curing / alloying of a particle-liquid mixture corresponding to an amalgamation preform.

[0077] For illustrative purposes, an exemplary method using a pair of paired surfaces and an amalgamated preform is described as an example, but according to various embodiments of the present invention, a bonding material may be disposed on one bonding surface or between bonding surfaces of the same substrate.

[0078] The bonding surfaces may include steel with a gold coating, for example, FCC (face-centered cubic) metal in bulk or plated form, ceramics, for example, silicon carbide, silicon dioxide, and / or aluminum nitride, and / or engineering metals such as insulators including glass, quartz, and / or sapphire. The insulators may or may not be metallized prior to bonding. The two bonding surfaces may be made of the same or different materials.

[0079] In various embodiments, optionally, the bonding surface may be pretreated to provide a bonding surface that is sufficiently cleaned and / or free of any excess oxide.

[0080] For example, the bonding surface may be solvent cleaned by immersing it in a solvent containing acetone, alcohol, and / or deionized water (di-water) at a temperature of 20°C or lower. In some other cases, the bonding surface may be cleaned first with acetone and alcohol, and then rinsed with deionized water to clean the surface.

[0081] In another example, if the bonding surface is made of a metal, e.g., Cu or Ag, an excess of copper or silver oxide may form on the bonding surface. The bonding surface may be pretreated to remove this excess oxide by, for example, an etching process (including plasma etching, acid etching, and / or base etching), and / or mechanical abrasion (e.g., blasting, peening, etc.). In an exemplary embodiment, the bonding surface may be pretreated by mechanical abrasion through p2000 grit or 0000 steel wool to polish the treated surface, and / or by chemical etching through NaOH with a subsequent deionized water rinse.

[0082] Meanwhile, it should be understood that a certain (or small) amount of natural oxides may remain on the bonding surface without being completely removed. This can prevent possible alloying between the bonding material and the bonding surface.

[0083] In various embodiments, the treated bonding surface may have a surface roughness in the range of 1 nm to 100 µm. Such roughness is desirable for providing adhesion with the bonding material during subsequent re-flow, redispersion, and / or curing processes. Conversely, a very smooth surface of the bonding surface may be used for the bonding / curing process, but it is not desirable to facilitate the re-mixing and curing of the bonding material.

[0084] In 904 of FIGS. 9a-9b, a particle-liquid mixture, which may correspond to, for example, an amalgamated preform, is placed between the bonding surfaces. The particle-liquid mixture may include various types of solid particles and nonmetals similar, identical, or different from those shown in FIGS. 1a-1b and FIGS. 2-8.

[0085] In some embodiments, the particle-liquid mixture for bonding / hardening / alloying may be obtained from the operation (102) of FIG. 1a-1b. In other embodiments, the particle-liquid mixture for bonding / hardening / alloying may be obtained from a Play-Doh type amalgamation preform (e.g., obtained at 106 in FIG. 1a) and / or a solid amalgamation preform (e.g., obtained at 108 in FIG. 1a and 109 in FIG. 1b) by a heating process, e.g., convection / induction heating generated by magnetic field control, and / or any other suitable heating process.

[0086] In 906 of FIG. 9, a first magnetic field is applied to disperse the particle-liquid mixture to form a particle-liquid dispersion.

[0087] In various embodiments, the application of the first magnetic field in operation (906) of FIG. 9 may be similar or identical to the application of the magnetic field in operation (104) of FIG. 1a-1b, thereby dispersing various types of solid particles in the particle-liquid mixture homogeneously or otherwise controllably to form a particle-liquid dispersion.

[0088] FIG. 10 illustrates an exemplary configuration having a solid amalgamated preform disposed between bonding surfaces for bonding / hardening / alloying according to various embodiments of the present invention.

[0089] In FIG. 10, for example, a solid amalgamation preform (1040) is placed between the bonding surfaces (1055) of mating substrates (1050). The bonding surfaces (1055) may have surface roughness disclosed to better handle the bonding material at the interface between them. Subsequently, as shown in FIG. 11, the solid amalgamation preform (1040) is heated, for example, using a magnetic processing device / mechanism (1030) (or any other suitable heating means) to liquefy the solid nonmetal (1020B) to form a corresponding particle-liquid mixture having a liquid nonmetal (1020A). Under magnetic control of 1070 in FIG. 11, the solid particles in the particle-liquid mixture may be homogeneously dispersed to form a particle-liquid dispersion.

[0090] As illustrated in FIG. 10-11, various particles as disclosed herein may include, for example, reactive particles (1001 / 1003 and 1101 / 1103) (e.g., including at least reactive magnetic particles (1001 / 1101) and reactive non-magnetic particles (1003 / 1103)), non-reactive magnetic particles (1006 / 1106), and / or any other possible solid additives (1008 / 1108).

[0091] Returning to FIG. 10, each bonding surface (1055) may be arranged to have a gap (1060) with the solid amalgamation preform (1040). The gap (1060) may have an initial thickness between the bonding surface (1055) and the solid amalgamation preform (1040). This initial thickness may allow the solid amalgamation preform (1040) to come into contact with each bonding surface (1055) when no pressure is applied to the solid amalgamation preform (1040) or when a small pressure (<1 MPa) is applied. In the undesirable case where a large pressure is applied, the mating bonding surfaces may tend to be compressed toward each other, and the components of the solid amalgamation preform may separate, potentially leading to an undesirable curing effect of the bonding material.

[0092] The initial thickness of the gap (1060) can be maintained throughout the bonding / curing / alloying process, for example, by using a physical spacer or spatial constraints of the two bonding surfaces (1050). For example, a jig or robot holding may be used to maintain the initial thickness of the gap (1060). In various embodiments, the spacer may be removed after the completion of the bonding / curing / alloying process of the solid amalgamation preform (1040), or may remain in place after the completion of the bonding / curing / alloying process and as an inactive part of the mating substrate (1050) of the bonding structure.

[0093] In various embodiments, the spacer may be manufactured from a material selected to add toughness or strength to the bond formed on the solid amalgamation preform to provide a formed bond having airtightness and conductivity. For example, the spacer may comprise a solid core material and a low-melt adhesive material formed on the solid core material. In this case, the polymer may reinforce the formed bond and promote stress relief from the solid amalgamation preform.

[0094] In various embodiments, the solid core material used in the spacer may be a metallic or organic polymer. The solid core material may be relatively ductile and may be deformed to fill the bonding cavity. The solid core material may have a melting point higher than the processing temperature for bonding so that the spacer remains in a solid state. Examples of the solid core material may include ductile metals such as copper, gold, silver, or aluminum that do not form negative oxidation couples with the substrate or amalgam. Other examples of the solid core material may include polymers such as nylon (polyamide).

[0095] The low-melt adhesive material formed on the solid core material may include a polymer having a melting temperature lower than the amalgam curing temperature, for example, thermoplastic polyurethane, styrene block copolymer, ethylene vinyl acetate, polyolefin, and / or polylactic acid.

[0096] FIG. 11-14 illustrates the controllable application of a first magnetic field to an exemplary particle-liquid mixture (1120) between bonding surfaces (1055) for magnetically dispersing a plurality of types of solid particles (e.g., particles (1101, 1103, 1106, and / or 1108)) in a liquid nonmetal (1020A) to form a particle-liquid dispersion. In this process, the reactive particles (1101 / 1103) may or may not react with the liquid nonmetal (1020A). For example, the first magnetic field may be applied so that the reaction occurs in a manner that does not destroy the shell material.

[0097] In one embodiment, a magnetic processing device, e.g., the device (1030) of FIG. 10, may be used to apply a first magnetic field. The magnetic processing device may include a coil wound around a bonding substrate (1050). The shape and dimensions of the wire used for coil winding may be determined based on the specific application of the first magnetic field. For example, the coil winding may have a uniform shape and dimensions and may be wound with a uniform or non-uniform distribution along the longitudinal direction of the bonding substrate.

[0098] The magnetic processing device may be connected to or include a controller (now illustrated), such as a computer controller, to control the polarity, strength, localization, movement, rotation, spinning, etc. of a first magnetic field by controlling the current and / or changes in the current of the coil winding. For example, a coil of a specific length may be selected by the controller to selectively apply the first magnetic field to a certain amount of particle-liquid mixture. In another example, the first magnetic field may be controlled and changed along a specific direction, for example, along the longitudinal direction of the bonding substrate. In another example, the controller may control the coil winding to repeatedly provide a rotational field and / or translational field back and forth along a specific direction, for example. In another example, the controller may control the coil winding to move the particle-liquid mixture / dispersion between different locations along the bonding surface of the bonding substrate, or to move the particle-liquid material out of the bonding substrate.

[0099] The first magnetic field may be applied in any suitable manner. Other suitable magnetic processing devices may include controllable electromagnets and / or physical permanent magnets for heating, mixing, dispersion, etc. For example, electronic control of the electromagnet and / or control of the moving physical permanent magnet may be performed to provide the first magnetic field.

[0100] In one embodiment, for example as illustrated in FIG. 12, a first magnetic field may be applied and aligned so that solid particles in a liquid nonmetal are pulled and moved toward an interface with a bonding surface. Meanwhile, the first magnetic field may be used to heat and maintain the nonmetal in a liquid form.

[0101] The first magnetic field can be moved at various angles to drag solid particles across two bonding surfaces, such as moving through a cross-section of the bonding material, for example, in any suitable shape or path of travel, as illustrated in FIG. 13. Solid particles dragged on the bonding surfaces can allow dispersion and wetting by scraping, removing, and / or destroying the natural oxide layer formed on the outermost layer (1305) of the bonding material (e.g., particle-liquid mixture) at the interface. In some embodiments, larger particles may allow for greater force compared to the viscous force experienced in the bonding material and may have a better chance of moving solid particles to the bonding material-bonding surface interface, for example, as illustrated in FIG. 14. In this way, controlling the movement of magnetic particles can improve surface wetting, thereby eliminating the need for fluxing agents and reducing cavities and gaps that often occur in conventional soldering materials.

[0102] The application of a first magnetic field can allow for the movement and distribution of all solid particles within the combined material. Often, instead of being driven by mechanical forces that compress the particles and drive out the liquid components, the initiated particle-liquid mixture / dispersion can be moved as a slug from one location to another without squeezing out the liquid components. Additionally, as illustrated in FIG. 14, the first magnetic field may also be used to flatten the particle-liquid mixture after it has been distributed as a large "slug".

[0103] Non-reactive solid particles can be used to drive, diffuse, mix, and / or heat a particle-liquid mixture to form a homogeneous particle-liquid dispersion, which can drive a homogeneous reaction for curing and further strengthen the combined material.

[0104] In one embodiment, a gradient static magnetic field may be used to align magnetic fibers or wires within a bonding material to provide preferential and anisotropic properties, see, for example, FIG. 15. For example, large magnetic particles of Fe, Ni, Co, Cr, Nb, and / or their alloys may be included in a particle-liquid mixture for bonding. The magnetic alignment may be modified to produce various properties such as anisotropic thermal conductivity and / or mechanical strength.

[0105] Instead of conventional mechanical mixing, the disclosed magnetic mixing can be performed, for example, via a dynamic magnetic field or a helical magnetic field, and drives the movement of solid magnetic particles (reactive or non-reactive, with or without large size) through the binding material. For example, under a dynamic magnetic field, multiple types of solid particles as disclosed can be attracted toward the interface between the binding material and the binding surface. Once the interface is reached, the solid particles can be moved in-plane to create a scraping or abrasion of the interface to mix a natural oxide of a nonmetal (e.g., 1305 in FIG. 13) from the outer surface of the binding material (e.g., at the interface) into the interior of the binding material. The removal or disturbance of the oxide layer can cause metallic alloying and increase the interfacial strength.

[0106] The shape of the bonding material can be designed, for example, according to the actual application. The disclosed magnetic mixing / dispersion can be random or sequential and can be performed simultaneously with magnetic heating.

[0107] In Figure 9a, a second magnetic field is applied to combine / harden / alloy the particle-liquid dispersion to allow for reaction or hardening between the reactive particles and the nonmetal. During this hardening operation, the temperature can be controlled by the second magnetic field along with the controllable composition of the particle-liquid dispersion. For example, the use of the second magnetic field can make the hardening temperature of a particular particle-liquid dispersion different from the hardening temperature of the corresponding material typically used in particle-liquid systems.

[0108] In various embodiments, the curing temperature may be about 250°C or lower, for example, about 150°C or lower, or about 50°C or lower (e.g., at room temperature). More specifically, in conjunction with a specific / controlled composition of the particle-liquid dispersion, the use of a second magnetic field may allow for much lower curing temperatures, such as, for example, 150°C or lower, 100°C or lower in some embodiments, and 50°C or lower in some embodiments. Of course, by controlling the second magnetic field and / or the composition of the particle-liquid dispersion, a high curing temperature, such as, for example, about 250°C, may also be controlled and used.

[0109] The second magnetic field may be applied in a manner different from the first magnetic field, for example, in terms of intensity, polarity, duration, etc. The second magnetic field may be provided by the same magnetic processing device as for the first magnetic field but may be adjusted differently.

[0110] Under a second magnetic field, the bonding material may be heated to a temperature that activates the chemical reaction between the reactive particles and the nonmetal for hardening / alloying, for example, above the melting point of the liquid component (the bonding material obtained in operation 904 of FIG. 9a) for the reaction to occur. During this hardening / bonding / alloying process, the temperature is 150°C or lower, 100°C or lower in some embodiments, and 50°C or lower in some embodiments.

[0111] In one embodiment, the first magnetic field may be inherently dynamic to drive the movement of particles to disperse the particle-liquid mixture to form a particle-liquid dispersion. For example, a fixed polar magnetic field may move within the space surrounding the entire setup as illustrated in FIG. 10. By controlling / applying the generated first magnetic field to prevent severe curing or heating from being induced, premature curing can be prevented. The second magnetic field may be controlled to have an effect similar to induction heating, where the movement of particles is restricted, and heating of the amalgamated preform occurs to drive curing.

[0112] As disclosed herein, the reactive particles may comprise a core-shell structure having a shell material that at least partially covers the core material. In one embodiment, the shell material of the reactive particles may be used to control the reaction rate between the reactive particles and the nonmetal for curing by controlling the kinetics and dissolution rate of the core material.

[0113] The shell material may have a thickness ranging from an atomic layer to about 100 nm, for example, a thickness of multiple atomic layers. The shell material may be thick enough to largely prevent solid-state alloying between the reactive particles and the solid nonmetal for the amalgamation preform, and thin enough to overcome undergoing such reactions during curing. The thickness of the shell material can be controlled depending on the selection of the nonmetal and the reactive particles.

[0114] In an exemplary embodiment where the core material is one or more of Fe and Ni, the shell material is an oxide of one or more of Fe and Ni, and the dissolution or penetration rate by an exemplary non-metallic Ga material through the shell material depends on the thickness of the shell material.

[0115] According to various embodiments, in addition to controlling the shell thickness, other mechanisms are applied to the core-shell structure of the reactive particles to control the reaction kinetics / rate for hardening / alloying.

[0116] For example, the reactive particles may include a shell material that reacts more slowly with the nonmetal than the core material to provide a longer curing time. For example, the shell material may be copper and the core material may be gold, and the nonmetal may be liquid Ga that reacts faster with gold than with copper.

[0117] Another exemplary reactive particle may comprise a reactive shell material (e.g., Cu) and a non-reactive core material (e.g., Co, and / or AlN, SiC, SiO2, TiO2, ZrO2, Al2O3, BeO, Si3N4, B4C, WC, and / or ceramic materials including diamond). In some cases, the reactive shell material may comprise a multilayer having an oxide layer that at least partially covers the reactive shell material. In one example, the shell material may be Cu and the core material may be Co, and the shell material may further comprise copper oxide covering the copper shell material. The magnetic properties of Co can be utilized for heating, mixing, or wetting, while the shell material may allow for a cohesive interface and strong bonding between the bonding surface and the bonding material. In another example, the shell material may be Cu and the core material may be AlN, and the shell material may further comprise copper oxide covering the copper shell material.

[0118] In various embodiments, a shell material may be selected to be incorporated to support and reinforce a solid alloy. In one example, the shell material of reactive particles may be non-reactive and / or may partially coat the inner particles of the core material (e.g., as a fragmented shell). When the inner particles are dissolved by the Ga liquid, the shell material may remain in the performance material to provide mechanical reinforcement and form a composite. Such a shell material may include a ductile material, including steel, and the core material may be Cu. In another example, the shell material may be a brittle oxide, such as ZnO or TiO2, which may rupture due to a mismatch in thermal expansion with the Cu, Ag, or Ni metal used as the core material inside the shell material. Hard and brittle shell materials can reinforce the solid alloy.

[0119] In various embodiments, the shell material may be destroyed during preform processing, such as hardening, bonding, or alloying. For example, the shell material of the reactive particles may be overcome, for example, through the dissolution of the nonmetal due to the application of a second magnetic field. For example, under the control of a second magnetic field, the oxide shell material may be destroyed so that its core material Fe or Cu can interact / react with the liquid nonmetal.

[0120] In various embodiments, the hardened material, i.e., the bond or solid alloy, may all be metallic solids. FIG. 16 illustrates an exemplary solid alloy doped with non-reactive magnetic particles according to at least various embodiments of the present invention. The solid alloy may have temperature stability higher than the hardening temperature. As shown in FIG. 16, the non-reactive particles may be retained in the solid alloy and may be uniformly dispersed therein to provide desirable properties such as, for example, mechanical strength, high thermal and electrical conductivity.

[0121] FIG. 9b illustrates another exemplary method for using an amalgamated preform according to various embodiments of the present invention.

[0122] After the operation (904) of FIG. 9b for placing the particle-liquid mixture corresponding to the amalgamation preform between the mating bonding surfaces, the particle-liquid mixture may be heated to a temperature higher than the low melting temperature of the nonmetal to re-flow the particle-liquid mixture, as exemplified in the operation (907) of FIG. 9b.

[0123] The heating process in operation (907) of FIG. 9 may include any heating means through conduction, convection, or radiation, etc. For example, a pulsed laser may be used to heat the particle-liquid mixture. The heating process may be arranged while a magnetic field is applied to the particle-liquid mixture. During this heating process in operation (907) of FIG. 9b, the temperature is 150°C or lower, 100°C or lower in some embodiments, and 50°C or lower in some embodiments.

[0124] In 909 of FIG. 9b, a magnetic field is applied to the particle-liquid mixture while it is heated so that a reaction between the reactive particle and the nonmetal may occur. During this reaction operation (909), the temperature is 150°C or lower, 100°C or lower in some embodiments, and 50°C or lower in some embodiments.

[0125] Under a magnetic field, the binding material can be dispersed and further heated to a temperature above the melting point of the liquid component (the binding material obtained in operation 904 of FIG. 9a) to activate the chemical reaction between the reactive particles and the nonmetal for hardening.

[0126] For example, a magnetic processing device (e.g., as shown in FIG. 10) may be used and controlled to adjust the magnetic field. For example, the magnetic processing device may include a coil wound around a mating coupling substrate. The shape and dimensions of the wire used for coil winding may be determined according to the specific application of the magnetic field.

[0127] The magnetic processing device may be connected to or include a controller, such as a computer controller, to control the polarity, strength, localization, movement, rotation, spinning, etc., of a first magnetic field by controlling the current and / or changes in the coil winding. For example, a coil of a specific length may be selected by the controller to selectively apply a magnetic field to a portion of the particle-liquid mixture to locally disperse solid particles in the particle-liquid mixture. In another example, the magnetic field may be controlled and changed along a specific direction, for example, along the longitudinal direction of the bonding substrate. In another example, the controller may control the coil winding to repeatedly provide a rotational field and / or translational field back and forth along a specific direction. In yet another example, the controller may control the coil winding to move the particle-liquid mixture / dispersion between different locations along the bonding surface of the bonding substrate, or to move the particle-liquid material out of the bonding substrate.

[0128] Other suitable magnetic processing devices may include electromagnets and / or physical permanent magnets controllable for heating, mixing, dispersion, etc. For example, electronic control of the electromagnet and / or control of the moving physical permanent magnet may be performed to provide a first magnetic field.

[0129] Magnetic particles within a particle-liquid mixture can be aligned, moved, and dispersed while heated. The magnetic field can be controlled to change the orientation of the particles and to provide mixing / dispersion of the magnetic particle movement within the cross-section of the particle-liquid mixture. The magnetic movement can be rotational, translational, or a combination of rotational and translational to cause the particles to move within the cross-section of the particle-liquid mixture. In this process, a bonding surface may come into contact with some of the moving liquid, and the moving liquid can subsequently allow a new interface by destroying and dispersing the natural oxide layer on the outermost surface of the particle-liquid mixture.

[0130] In addition to dispersing particles more uniformly in a particle-liquid mixture, the magnetic field can be controlled so that the reaction between the reactive particles and the base material forms a solid alloy.

[0131] As such, under a magnetic field, various types of solid particles can be oriented, moved, and / or aligned along the entire cross-section of the binding material containing the particles. Under a dynamic magnetic field, the particles are aligned and move along with the movement of the magnetic field. Various movements of the particles can be introduced under the application of a magnetic field. For example, under a spinning magnetic field, radial movement of the particles can be generated, which can essentially scrape and mix the binding material at the interface between the binding material and the binding surface. The movement of the particles can induce agitation at the interface. By dynamically controlling / modulating the magnetic field, the concentration at different locations can be controlled. The movement of the particles can fill the cavities of the binding material to redistribute the particles across the entire cross-section of the binding material. This distribution can provide a uniform chemical composition. Additionally, surface bonding at the interface can be disrupted and altered due to the movement of the particles to provide wettability to the contact substrate, which can homogenize the composition into a uniform distribution. In addition, fluctuations in the magnetic field and heating through the cross-section can provide a localized distribution of heating and concentration.

[0132] Typically, fluxing is required to ensure the adhesion of soldering / bonding materials that form a natural oxide layer. Generally, flux is applied and used to clean and wet the bonding surface prior to the bonding process. However, flux has several disadvantages. For example, it can cause corrosion and contamination to the bonding area, and poses adverse health risks due to smoke and gas emissions during bonding and processing. Additionally, flux materials are often mixed with metallic powders in the preform to facilitate interfacial bonding with the bonding surface. For instance, flux may be mixed into the surface or exterior of the bonding material, but may be absent from the interior. However, stirring at the bonding interface is necessary to break down the natural oxide layer floating on the outer surface of the bonding material; otherwise, the adhesion at the interface becomes poor, which is undesirable. Conventional preforms are unable to adhere sufficiently to most bonding surfaces.

[0133] A controlled magnetic field can cause various types of solid particles, as disclosed, to move toward the interface between the bonding material and the bonding surface, and to further generate scratching or scraping at this interface to destroy the natural oxides of the nonmetal on the outer surface of the bonding material (e.g., 1305 in FIG. 13) and to mix the destroyed natural oxides from the outer surface of the bonding material (e.g., at the interface) into the interior of the bonding material. The natural oxides of the nonmetal scraped from the outer surface of the bonding material into the interior can mechanically strengthen the resulting bonding material and additionally cause the nonmetal to directly interact with the bonding surface and wet it.

[0134] In this way, by applying the disclosed particle-liquid mixture in combination with a magnetic field controlled according to various embodiments of the present invention, the need for pre-wetting the bonding substrate or for any fluxing agent in the bonding material is eliminated.

[0135] The hardened bond produced in a completely new and much more stable alloy state can now withstand much higher temperatures experienced by the bond surface (and parts thereof). In one embodiment, the hardened bond produced can withstand temperatures higher than the hardening temperature, for example, above about 200°C, for example above about 260°C.

[0136] Although the present invention is disclosed as described above, the present invention is not limited by the disclosed embodiments. Various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, the scope of the present invention shall be in accordance with the scope described in the claims.

Claims

Claim 1 An amalgamation preform comprising a plurality of types of solid particles dispersed in a base metal having a melting point of less than 200°C and a base metal including one of a liquid base metal and a solid base metal, wherein the plurality of types of solid particles comprises at least: non-reactive magnetic particles that are reactive to a magnetic field to controllably disperse the plurality of types of solid particles in the base metal, and reactive particles capable of reacting with the base metal under a magnetic field for amalgamation, wherein the reactive particles comprise at least a reactive metallic material, and the reactive metallic material comprises Fe, Ni, Cu, Ag, Au, In, Cu, Sn, Bi, Zn, Ti, V, Cr, Mo, Nb, Zr, Hf, Pt, Ir, or a combination thereof, and the particles of the reactive particles comprise a core-shell structure, wherein: the core-shell structure comprises a core material and a shell material that is different from the core material and at least partially surrounds the core material, wherein the core material has a reaction rate with the base metal that is different from the shell material, and the shell material has a thickness of atomic layer to A preform having a thickness in the range of 100 nm, wherein the core material comprises a reactive metal material and the shell material comprises an oxide layer of the reactive metal material. Claim 2 In claim 1, the nonmetal comprises a preform including Ga, In, Sn, Bi, Pb, Cd, Hg, Rb, Zn, Bi, or a combination thereof. Claim 3 delete Claim 4 delete Claim 5 The core-shell structure of claim 1, wherein the core-shell structure comprises one or more of the following: a core-shell structure having a shell material comprising one or more oxides of Fe and Ni, and a core material comprising one or more of Fe and Ni; a core-shell structure having a shell material comprising Cu and a core material comprising Au; a core-shell structure having a shell material comprising steel and a core material comprising Cu; a core-shell structure having a shell material comprising ZnO or TiO2 and a core material comprising Cu, Ag, Ni, or a combination thereof; and a core-shell structure having a shell material comprising Cu and copper oxide that at least partially covers Cu, and a core material comprising Co, BeO, Si3N4, B4C, WC, diamond, AlN, SiC, SiO2, TiO2, ZrO2, Al2O3, or a combination thereof. Claim 6 In claim 1, the reactive particles are a preform comprising reactive magnetic particles, reactive non-magnetic particles, or a combination thereof. Claim 7 In claim 6, the reactive magnetic particles comprise one or more of Fe and Ni, the reactive magnetic particles have an average size greater than 50 μm, and / or the reactive non-magnetic particles comprise a preform comprising Cu, Ag, Au, In, Cu, Sn, Bi, Zn, Ti, V, Cr, Mo, Nb, Zr, Hf, Pt, Ir, or a combination thereof. Claim 8 A preform according to claim 1, wherein the ratio of the non-metal to the plurality of types of solid particles is in the range of 4:1 to 1:4 by weight. Claim 9 The preform of claim 1, wherein the plurality of types of solid particles have an average size in the range of 100 nm to 100 µm, the reactive particles have an average size in the range of 100 nm to 50 µm, and / or the non-reactive magnetic particles have an average size in the range of 5 µm to 100 µm. Claim 10 In claim 1, the non-reactive magnetic particles are a preform comprising Co-containing particles, Nd-containing particles, Cr-containing particles, or a combination thereof. Claim 11 The non-reactive magnetic particles of claim 1 comprise large-sized magnetic particles having at least one dimension greater than 5 μm, wherein the large-sized magnetic particles comprise microwires, microfibers, or a combination thereof, and the microwires and microfibers are preforms aligned according to the movement of a magnetic field applied during the manufacture of an amalgamation preform. Claim 12 The plurality of solid particles according to claim 1 further comprises an additive comprising semiconductor particles, metal-doped semiconductor particles, or a combination thereof, and the semiconductor particles are preforms comprising SiC particles, AlN particles, SiO2 particles, or a combination thereof. Claim 13 A liquid nonmetal having a melting point of less than 200°C, and an amalgamation preform comprising a plurality of types of solid particles magnetically dispersed in the liquid nonmetal without solidifying the liquid nonmetal, wherein the plurality of types of solid particles comprises at least: non-reactive magnetic particles and reactive particles that are reactive to a magnetic field to controllably disperse the plurality of types of solid particles in the liquid nonmetal, wherein the reactive particles can react with the liquid nonmetal under a magnetic field for amalgamation, and no reaction occurs between the reactive particles and the liquid nonmetal at a temperature of 25°C or lower, wherein the reactive particles comprise at least a reactive metallic material, wherein the reactive metallic material comprises Fe, Ni, Cu, Ag, Au, In, Cu, Sn, Bi, Zn, Ti, V, Cr, Mo, Nb, Zr, Hf, Pt, Ir, or a combination thereof, and wherein the particles of the reactive particles comprise a core-shell structure, wherein: the core-shell structure comprises a core material and a shell material that is different from the core material and at least partially surrounds the core material. A preform comprising, wherein the core material has a reaction rate with a nonmetal different from that of the shell material, the shell material has a thickness in the range of an atomic layer to 100 nm, the core material comprises a reactive metal material, and the shell material comprises an oxide layer of the reactive metal material. Claim 14 A method for manufacturing an amalgamation preform according to claim 1 or claim 13, comprising: providing a particle-liquid mixture containing a plurality of types of solid particles and a liquid nonmetal; applying a magnetic field to the particle-liquid mixture to magnetically disperse a plurality of types of solid particles within the liquid nonmetal without substantially inducing a reaction between the reactive particles and the liquid nonmetal to form a particle-liquid dispersion; and manufacturing an amalgamation preform comprising a plurality of types of solid particles and a nonmetal, wherein the plurality of types of solid particles comprises at least reactive particles and non-reactive magnetic particles, and the particles of the reactive particles comprise a core-shell structure, wherein: the core-shell structure comprises a core material and a shell material that is different from the core material and at least partially surrounds the core material, the core material has a reaction rate with a nonmetal different from the shell material, and the shell material has a thickness in the range of atomic layer thickness to 100 nm thickness, the core material comprises a reactive metal material, and the shell material comprises an oxide layer of the reactive metal material. Claim 15 A method of using an amalgamated preform according to claim 1 or claim 13, comprising: providing mating bonding surfaces; placing a particle-liquid mixture corresponding to the amalgamated preform between the mating bonding surfaces; and applying a magnetic field to the particle-liquid mixture. Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete Claim 21 delete Claim 22 delete Claim 23 delete Claim 24 delete Claim 25 delete Claim 26 delete Claim 27 delete Claim 28 delete Claim 29 delete Claim 30 delete Claim 31 delete Claim 32 delete Claim 33 delete Claim 34 delete Claim 35 delete Claim 36 delete Claim 37 delete Claim 38 delete Claim 39 delete Claim 40 delete Claim 41 delete Claim 42 delete Claim 43 delete Claim 44 delete Claim 45 delete Claim 46 delete Claim 47 delete Claim 48 delete Claim 49 delete Claim 50 delete Claim 51 delete Claim 52 delete Claim 53 delete Claim 54 delete

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