Continuous interconnects between heterogeneous materials

Abstract

The invention relates to a continuous interconnection between heterogeneous materials. A structure may include a first material, a second material connected to the first material at a junction between the first material and the second material, and one or more media extending across the junction to form a continuous interconnect between the first material and the second material, where the first material and the second material are heterogeneous. The structure may further include a transition at a junction between the first material and the second material. The one or more media may include an electrically conductive functional material. The structure may also include a third material connected to the second material at a second junction between the second material and the third material, the medium may extend across the second junction to form a continuous interconnect between the first material, the second material, and the third material, and the second material and the third material may be heterogeneous.

Description

[0001] This application is a divisional application of an application filed on May 28, 2020, with application number 202080039373.3 and invention name “Continuous interconnection between heterogeneous materials”. CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 853,481, filed May 28, 2019, which is incorporated herein by reference. background

[0003] The inventive principles disclosed herein generally relate to interconnections between two dissimilar materials, and more particularly to structures having one or more dielectrics extending between two dissimilar materials to form a continuous interconnect between the materials, and / or methods of forming such structures. Overview

[0004] A structure may include a first material, a second material connected to the first material at a junction between the first and second materials, and one or more dielectrics extending across the junction to form a continuous interconnection between the first and second materials, wherein the first and second materials are heterogeneous. The structure may further include a transition portion at the junction between the first and second materials. The transition portion may include an overlap portion. The one or more dielectrics may include a functional material. The functional material may be electrically conductive. The functional material may include a conductive gel. The first material may be significantly more rigid than the second material. The first material may be significantly more elastic than the second material. The structure may also include a first sealant disposed on the first material to substantially enclose a portion of the dielectric. The structure may also include a second sealant disposed on the second material to substantially enclose a portion of the dielectric. The first material may include a through-hole through which at least a portion of the dielectric passes. The structure may include an overlap portion at the junction between the first and second materials, with the through-hole extending through the overlap portion. The structure may also include an electrical component attached to the first material and electrically coupled to the dielectric.

[0005] The junction between the first material and the second material may include a first junction, the structure may further include a third material connected to the second material at a second junction between the second material and the third material, the dielectric may extend across the second junction to form a continuous interconnection between the first material, the second material, and the third material, and the second and third materials may be heterogeneous. The dielectric may be conductive, and the structure may further include a first electrical component attached to the first material and electrically connected to the dielectric, and a second electrical component attached to the third material and electrically connected to the dielectric.

[0006] A sensor structure may include a first substrate comprising a first material, a conductive contact layer comprising a second material disposed on the first substrate, a second substrate comprising a third material disposed on the first substrate, and a conductive gel arranged in a pattern on the second substrate and forming a continuous electrical interconnection with the conductive contact layer, wherein at least two of the first material, the second material, and the third material are heterogeneous. The sensor structure may further include an electrical component disposed on the second substrate and electrically connected to the continuous electrical interconnection. The first substrate may include a through-hole through which the continuous electrical interconnection is connected to the conductive contact layer.

[0007] A method may include connecting a first material to a second material at a joint, and forming a continuous interconnect between the first material and the second material across the joint, wherein the first material and the second material may be heterogeneous. The method may further include encapsulating the continuous interconnect. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The drawings are not necessarily drawn to scale, and for illustrative purposes, elements of similar structure or function may generally be represented by similar reference numerals throughout the drawings. The drawings are intended only to facilitate description of the various embodiments described herein. The drawings do not describe every aspect of the teachings disclosed herein and do not limit the scope of the claims. To prevent the drawings from becoming obscure, not all components, connections, etc. may be shown, and not all components may have reference numerals. However, the pattern of component configurations can be easily seen from the drawings.

[0009] Figure 1 An embodiment of a structure according to some inventive principles of this patent disclosure is shown.

[0010] Figure 2 Another embodiment of a structure according to some inventive principles of this patent disclosure is shown.

[0011] Figure 3 is an exploded perspective view illustrating an example embodiment of an interconnect design according to some inventive principles of this disclosure.

[0012] Figure 4 is a cross-sectional view of another illustrative embodiment of a heterostructure according to some inventive principles of this disclosure.

[0013] Figure 5 Another example embodiment of a heterostructure using conductive gel as traces according to some inventive principles of this disclosure is shown.

[0014] Figure 6 Another embodiment of a structure having serial interconnections according to some inventive principles of this disclosure is shown.

[0015] Figure 7 and Figure 8 2 are side and top views, respectively, of an embodiment of a structure having continuous interconnections between different materials according to some inventive principles of this disclosure.

[0016] Figure 9 yes Figure 7 and Figure 8 Another side view of the structure.

[0017] Figure 10 is a cross-sectional view of another embodiment of a structure having continuous interconnections between different materials according to some inventive principles of this disclosure.

[0018] Figure 11 is a cross-sectional view of another illustrative embodiment of a heterostructure according to some inventive principles of this disclosure. Detailed description

[0019] Figure 1 An embodiment of a structure according to some inventive principles of this patent disclosure is shown. Figure 1 The system may include at least two heterogeneous materials: material A (10) and material B (12). Materials A and B may differ in that they have at least one different mechanical property, constraint, processing parameter, etc. One or more dielectrics may extend between materials A and B to form a continuous interconnection between the materials. Figure 2 Shows something like Figure 1 Another embodiment of the embodiment, but Figure 2 Embodiments may include a transition A / B (16) between materials A and B.

[0020] Examples of suitable media include viscous, elastic, viscoelastic, and / or any other material that can deform in response to deformation of one or more of materials A and B and then return to a previous form when one or more of materials A and B returns to the previous form. The one or more media can return to the previous form by its own action (e.g., if the medium is an elastic material) or by the action of one or more of materials A and B returning to the previous form (e.g., if the medium is a fluid).

[0021] In some embodiments, the medium may include one or more functional materials, each of which may have at least one non-structural function, such as: conducting electricity, light, sound, etc.; sensing one or more stimuli, such as stress, strain, pressure, temperature, elongation, etc.; mass transfer (e.g., mass transfer of the material itself); heat transfer; mechanical connection, such as transmitting force, motion, pressure, vibration, etc.; and / or any other type of function. In some embodiments, the functional material may have at least one fluid property or component, such as being a fluid component of a fluid phase material or a gel material.

[0022] In some embodiments, functional materials can be implemented using viscoelastic materials with both fluid and solid components. This material can perform, for example, an electroactive function (such as conducting electricity), or it can serve as a mechanical interconnect, an actuation interconnect, a fuel line, a fluid reservoir, or any other function. The viscoelastic interconnect material can be arranged in any suitable geometry to accommodate any desired function.

[0023] In rheology, G* may refer to a complex shear modulus that may include two components: G' and G", which may be referred to as the storage modulus and loss modulus, respectively. The storage modulus may essentially characterize the elastic component of a material, while the loss modulus may characterize the viscous or liquid component of a material. In some embodiments, by selecting a functional material with a higher G' than one or both of materials A or B, the functional material may withstand a degree of compression during formation and / or use of a structure. In some embodiments, and depending on implementation details, the storage modulus of a functional material may be considered "higher" than the storage modulus of one or both of materials A or B if it is higher by an amount that enables the functional material to withstand compression or other distortional stimuli during formation and / or use while remaining functional after structure formation and / or use.

[0024] Examples of different mechanical properties of materials A and B include modulus (e.g., Young's, shear, expansion, etc.), hardness (Shore, Mohs, Brinell, Rockwell, etc.), strength (e.g., tensile, compressive, etc.), density, etc.

[0025] Examples of different processing parameters for materials A and B include temperature, pressure, time, reagents (eg, reactants, solvents, catalysts, activators, etc.), exposure to UV, IR, RF, ultrasonic treatment, etc.

[0026] Examples of different constraints for materials A and B include: deformation limitations (e.g., because rigid parts are mounted on them, placed on objects such as the human body or sensitive mechanical instruments), exposure limitations (e.g., limited to temperature, radiation, UV, IR, RF, ultrasound, chemicals, etc.), etc.

[0027] The one or more media forming the interconnect may be formed on one or more surfaces of materials A and / or B or transition A / B, in a channel through either of materials A and / or B or transition A / B, or in any other arrangement that creates an operative interconnect between materials A and B.

[0028] The transition portion A / B (if any) may include an overlap, an interleaving, a material gradient, and / or the like between materials A and B, and / or one or more intermediate, transitional, buffer, etc. materials between materials A and B.

[0029] The deformation of one or more of materials A and B and the corresponding deformation of interconnect 14 can be in response to any or all of tensile, compressive, stretching, flexing, twisting, expansion, etc. forces on one or more of materials A and B.

[0030] Examples of types of interconnects formed by one or more media may include mechanical, electrical, electronic, electromechanical, electromagnetic and / or other electrically active interconnects, optical, photonic, audio, mass transmission, and the like.

[0031] Examples of materials suitable for use as materials A and B in any combination may include any type of natural and / or synthetic polymers, including rubber and plastic materials, such as silicone-based materials including polydimethylsiloxane (PDMS), polyurethane rubber including thermoplastic polyurethane (TPU), ethylene propylene diene monomer (EPDM), neoprene and epoxy resins, pure and alloy metals, woven or non-woven fabrics, wood, leather, paper, fiberglass and carbon and other composite materials, or any combination of the above materials.

[0032] Examples of materials suitable for use as one or more dielectrics forming interconnects include, but are not limited to, deformable conductors including conductive gels such as gallium-indium alloys, some examples of which are disclosed in U.S. Patent Application Publication No. 2018 / 0247727, published on August 30, 2018, which is incorporated by reference. Other suitable electroactive materials may include: any conductive metal, including gold, nickel, silver, platinum, copper, etc.; semiconductors based on silicon, gallium, germanium, antimony, arsenic, boron, carbon, selenium, sulfur, tellurium, etc.; semiconductor compounds including gallium arsenide, indium antimonide, and many metal oxides; organic semiconductors; and conductive non-metallic substances such as graphite. Other examples of conductive gels include graphite-based gels or other forms of carbon and ionic gels. Examples of suitable non-electroactive compositions include many other types of gels, such as silicone gels and chafing fuels such as Sterno. Other examples include liquids such as water, oil, ink, alcohol, etc. (any of which can be electroactive or non-electroactive), and any elastic material, which can be electroactive or non-electroactive.

[0033] Some additional inventive principles disclosed in this patent involve using methods such as Figure 1 and Figure 2The structures shown in the patent disclosure may be used as interconnects between heterogeneous materials that carry various specialized components, for example, in deformable electronic assemblies (such as flexible hybrid electronics (FHE) assemblies). In some non-limiting example embodiments, the interconnects may span heterogeneous joints between a deformable circuit board (such as a printed circuit board (PCB) like a flexible printed circuit board (FlexPCB) and / or a stretchable printed circuit board (StretchPCB)) and other deformable structures (such as TPU or silicone structures). Techniques that can be used to form these structures may include molding, adhesive bonding, thermoforming, tape bonding, ultrasonic bonding, and / or others. In some embodiments, these techniques can be combined with FHE technology and one or more interconnects disclosed in this patent disclosure to create one or more integrated textile / electronic assemblies with applications, for example, in industrial electronic devices, consumer electronic devices, and / or wearable electronic devices.

[0034] Mixed-mode interconnects, particularly between hard and soft materials or between rigid components and materials that conform to nonlinear shapes, can present challenges in deformable electronics such as FHE. FHE and other deformable electronics can be applied to the Internet of Things (IoT) and wearable applications, where electronic devices can exist in close proximity with mechanical elements that are traditionally considered distinct from conventional electronic components. Materials such as fabrics, rubber membranes, thermoformed plastics, and the like can directly integrate electronic components to support intelligent or actively controlled functionality.

[0035] Interconnections between dissimilar materials can be handled with specialized solders, conductive adhesives, or mechanical connectors. However, some of these may involve compatibility with separate traces built on two different substrates, each of which may have its own mechanical constraints. This can involve engineering both the dissimilar material interconnects and the mechanical structure, and imposes substantial constraints and overhead on the design of FHE or other deformable electronic devices.

[0036] The inventive principles disclosed herein can circumvent potential interconnect issues, such as multimodal metallization, by using continuous interconnects created through vias or other channels made of conductive gel and / or other conductive functional materials that are cut or formed in a hybrid substrate, printed directly on the substrate, or arranged with the substrate in any other suitable manner. In some embodiments, continuous circuits including vias and other structures having single and / or hybrid material multilayer circuit configurations can be fabricated using interconnects formed from conductive gel and / or other conductive functional materials. In some embodiments, components can be directly coupled to conventional electronic components, including surface mount components, flexible circuits, and conductive fabrics, through vias in an adhesive substrate that can be filled with conductive gel and / or other conductive functional materials. Both of these structures can produce low-impedance ohmic contacts that are, for example, resistant to strain cycling and / or flex testing and / or capable of withstanding dynamic loads imposed on the structure during both final assembly and during use in applications such as wearable electronics, strain monitoring electronics, and the like, where dynamic movement may be expected.

[0037] In some embodiments, the inventive principles disclosed in this patent can be applied to many substrate materials and manufacturing methods that can allow both: carrying rigid surface mount components on a FlexPCB or StretchPCB substrate, and creating mechanically robust interconnects attached to PCB components that should be able to withstand significantly greater strains, all of which are spanned by a continuous conductor composed of conductive gel.

[0038] In some example embodiments, a FHE or other deformable electronic device may include a first substrate portion that carries surface-mount components and a second substrate portion that acts as a relatively high-elongation textile-integrated conductor and / or strain gauge, the conductor and / or strain gauge being made of, for example, a conductive gel. The higher-elongation portion of the circuit may provide a variable resistance and / or conductive path to a low-elongation flexible circuit that may carry one or more passive and / or active surface-mount technology (SMT) components capable of creating a visual output, such as the stretching experienced by the high-elongation portion.

[0039] According to some of the inventive principles disclosed in this patent, some examples of materials that can be used for FHE devices or other deformable devices include, but are not limited to, the following: any TPU, including, for example, low Shore A TPU and / or other TPU with high Shore A; thermoset and / or epoxy-based films; silicone, such as any type of cured silicone, which can be applied to, for example, high-stretch knitted fabrics; copper or metal-clad polyamide or other substrates that can be used for FlexPCB, StretchPCB and / or the like; and any active and / or passive through-hole and / or surface-mount components. In some example embodiments, copper-clad polyamide and SMC components can be used to form stable electrical connections with through-holes filled with conductive gel and can be applied as components in, for example, hybrid assemblies.

[0040] Figure 3 is an exploded perspective view illustrating an example embodiment of an interconnect design suitable for use with FHE devices or other devices according to some inventive principles disclosed herein. Two pads 101 and 102 having diameters D1 and D2, respectively, may be printed on separate layers of different substrates A (103) and B (104), for example with holes passing through the pads, thereby achieving electrical continuity. Pad 101 may communicate with trace 107 on substrate A, while pad 102 may communicate with trace 108 on substrate B.

[0041] The pad size and via size can be selected to facilitate the design of the circuit board for manufacturability. In some example embodiments of heterojunctions on flexible and / or stretchable substrates, the size of these features can be selected based on the expected deformation of the substrate and / or to facilitate assembly and testing of the heterojunctions. In some embodiments, these via pads can extend directly to a surface mount component that can be adhered to the pads on a surface or circuit (e.g., a polyamide circuit).

[0042] Figure 3 The example of FIG. 1 shows a transition substrate A / B (105) having a through hole 106 of diameter D3 between the overlapping portions of substrates A and B, but the transition substrate may be omitted in some embodiments. The materials used for substrates A and B and transition substrate A / B (if used) may be selected from any of the materials identified above or any other suitable material. The pads, traces, and filler material for the through holes may be implemented with conductive gel or any other suitable conductive material.

[0043] Figure 4is a cross-sectional view of another example embodiment of a heterostructure (which in some embodiments may be implemented as a stack) using conductive gel and / or other interconnecting medium 114 as traces according to the present disclosure. Substrate A (110) may be overlapped and directly attached to substrate B (112). In other embodiments, a transition substrate may be used. In this embodiment, vias 116 may be formed through substrate A, for example, because traces 122 and / or pads 124 on substrate A may be aligned on top of pads 120 and / or traces 118 on substrate B, the conductive gel in the via 116 of substrate A may directly contact pads 120 on top of substrate B.

[0044] Figure 4 The illustrated structure may include one or more sealants to constrain and / or protect the traces, pads, and / or vias of the conductive gel and / or other interconnecting medium 114. For example, at least a portion of substrate A may be coated with sealant A (126), and at least a portion of substrate B may be coated with sealant B (128). Any suitable material may be used for the sealant, such as silicone-based materials such as PDMS, TPU, polyurethane, epoxy, polyester, polyamide, varnish, and any other material that can provide a protective coating and / or help hold the components together. Substrates 110 and 112 may be bonded together using any suitable technique, including adhesive bonding, thermoforming, tape bonding, ultrasonic bonding, etc.

[0045] Similar to Figure 4 Examples of applications in which the structure shown in may be useful include applications in which substrate A may be implemented with a material that can be used to carry one or more electronic components, while substrate B may be implemented with a material that can be used to provide connections to remote sensors, displays, electronic modules, etc. For example, substrate A may be made of a relatively rigid material, while substrate B may be made of a relatively flexible and / or stretchable material.

[0046] In some embodiments, traces 122 may be formed on the bottom of substrate A (110), thereby eliminating vias 116. In such embodiments, sealant A (126) may be applied to the bottom surface of substrate A (110). In some embodiments, sealant A (126) and sealant B (128) may be combined into a single component.

[0047] In some embodiments, Figure 4 Some or all of the structures shown in (and any other structures described in this disclosure) can be manufactured at least in part using any of the materials and / or manufacturing techniques described in U.S. Patent Application Publication No. 2020 / 0066628, published on February 27, 2020, which is incorporated by reference and can be used in conjunction with any of the methods and / or articles described herein.

[0048] Figure 5 Another example embodiment of a heterostructure using conductive gel as traces according to some inventive principles of this patent disclosure is shown. Figure 5 In the illustrated embodiment, a thermoset plastic laminate tape 130 (Material A) can overlap a TPU tape 132 (Material B) at an overlap region 134 (A / B). A heterogeneous interconnect dielectric made of, for example, a eutectic gallium alloy can have a first portion 136 on Material A, a second portion 138 on Material B, and a transition portion 140 in the overlap region 134. All three portions of the trace can be encapsulated, for example, with one or more encapsulants such as silicone, TPU, polyurethane, epoxy, etc.

[0049] Thermoset plastic (Material A) and TPU (Material B) can have significantly different mechanical properties that are spanned by the continuous conductive trace, thus forming a heterogeneous interconnect that transitions between the two heterogeneous materials. For example, in some embodiments, the thermoset plastic laminate (Material A) can be significantly more rigid than the TPU (Material B).

[0050] An electromechanical connector, such as solderable connector 142, can overlap the second portion 138 of the trace in overlap region 144 to form another heterogeneous electrical connection between the continuous trace and any other electrical device. Alternatively, in some embodiments, a polyamide layer can be adhered to the conductive fabric as a terminal layer to provide an interconnection between the conductive gel encapsulated in TPU or silicone and the solderable connector mechanically connected to the conductive fabric.

[0051] Figure 6 Another embodiment of a structure with continuous interconnection according to the present disclosure is shown. Figure 6 In the illustrated embodiment, an outer ring 150 of conductive gel and an inner ring 152 of conductive gel can be patterned on a first substrate 154 (Material A) formed from a relatively rigid material, such as a thermoset plastic. The first substrate 154 can transition to a second substrate 156 (Material B), formed from a relatively flexible and / or stretchable material, such as silicone. The transition between the first and second substrates 154, 156 can be achieved by overlapping, butting, or any other means. A first linear trace 158, which can be electrically connected to the outer ring 150, can be patterned on the first and second substrates 154, 156 to span the transition between Material A and Material B. A second linear trace 160, which can be electrically connected to the inner ring 152, can be patterned on the first and second substrates 154, 156 to span the transition between Material A and Material B.

[0052] One or more two-terminal electronic components, such as light-emitting diodes (LEDs) 162, can be mounted on first substrate 154, with each of the inner and outer rings in direct contact with one terminal. First substrate 154 can be encapsulated, for example, with a transparent encapsulant such as silicone, so that the LEDs are visible through the encapsulant. A second substrate can be encapsulated, for example, with another layer of silicone, with linear traces 158 and 160 bonded therebetween. Portions of linear traces 158 and 160, shown as dashed lines, can be covered by the encapsulant on second substrate 156, which, in some embodiments, may not be transparent.

[0053] In some embodiments, the fabric mesh can be applied to the first substrate 154, for example, by including it within an encapsulant, or by combining it with another encapsulant, to provide selective strain confinement of the first substrate 154 and the pattern of conductive gel and LEDs formed thereon.

[0054] therefore, Figure 6 The illustrated embodiment can provide an electronic assembly in which a relatively rigid, yet still flexible and / or stretchable, first substrate 154 (material A) can provide a base for electronic components, while in some implementations, electrical connections to the base are provided through a relatively more flexible and / or stretchable second substrate 156 (material B) without the use of any solid wires.

[0055] Conductive gels made from gallium alloys, such as those described in U.S. Patent Application Publication No. 2018 / 0247727, may be particularly beneficial for interconnects between heterogeneous materials, as they can be patterned onto a variety of substrates, including TPU, silicones, epoxies, EPDM, and various thermoset elastomers. In some embodiments, the patterning method can be graphical in nature, forming a mechanical bond between the substrate and the conductive gel. In some embodiments, there may be no curing stage or chemical reaction that facilitates wetting of the functional pattern onto a wide range of substrates. An example is a composition of a gallium-indium-tin eutectic alloy, in which cross-linked gallium oxide nanostructures have been introduced to modify viscosity and wetting parameters, allowing the material to be controllably patterned onto a variety of substrates. Eutectic gallium alloy gels may also lack a structure that decomposes during strain cycling, as the material can conduct electricity in an amorphous fluid state, making it robust when strain cycling reaches the upper limits of its substrate. Therefore, they may offer an effective solution for interconnects between heterogeneous materials in FHE and many other applications, particularly at critical hard-to-soft transitions. Eutectic gallium alloy gels can also have excellent electrical properties, which provide low resistance DC connections and transmission line parameters (primarily S11) up to 5 GHz and above.

[0056] Figure 7 and Figure 82 are side and top views, respectively, of an embodiment of a structure having continuous interconnections between different materials according to some inventive principles of this patent disclosure.

[0057] Figure 7 and Figure 8 Embodiments may include first, second, and third distinct substrates 18, 20, and 22. In this example, first substrate 18 may be a rigid TPU, second substrate 20 may be a more flexible but still strong TPU, and third substrate 22 may be a soft TPU, but the principles of the invention are not limited to these details, and any combination of materials with various properties may be used. The first and second substrates may be joined together at joint 19 using any suitable bonding technique, while the second and third substrates may be joined together at joint 21 using any suitable bonding technique. Figure 7 and Figure 8 The components in the diagram are not necessarily to scale. For example, the substrate may be made of a very thin sheet of material, in which case Figure 7 and Figure 8 The vertical proportions are exaggerated.

[0058] Traces of a conductive medium (such as a conductive gel) may be formed in a U-shaped pattern 28 on the upper surface of the substrates and span the joint between the substrates. Due to the rigid nature of the first substrate 18, the ends of the U-shaped pattern 28 may terminate at contact pads 24 and 26, which may be conventional electrical contact pads. Although Figure 7 and Figure 8 Although not shown, a sealant may be formed on the top surfaces of the U-shaped pattern 28 and the substrates 18 , 20 , and 22 .

[0059] The resulting structure can bend in response to various forces, with different substrates providing different bending radii, e.g. Figure 9 As shown in R1 and R2, Figure 9 yes Figure 7 and Figure 8 Another side view of the structure, Figure 9 The structure is shown deforming. In some embodiments, this structure can act as a strain relief.

[0060] Figure 7 and Figure 8The structure can also include transitions between other materials, such as TPU to epoxy, silicone to epoxy, silicone to fabric or TPU, etc. In some embodiments, and depending on the implementation details, having a continuous interconnect between TPU and silicone can be particularly beneficial because making electrical connections with silicone is often difficult, but making electrical connections with TPU is relatively easy. Therefore, electrical connections can be placed on a TPU substrate, which can then transition to silicone, which can provide a more sensitive substrate for sensors made of deformable conductors such as conductive gel.

[0061] In some embodiments, after the circuit is printed via stencil printing, flexographic printing, or some other deposition process, a sealant layer with deformable conductor-filled vias can be added, or the exposed circuit can simply remain exposed. Next, an integrated circuit (IC) or other electronic device can be placed over the circuit. The metal layer on the IC can form a low-impedance ohmic contact with the conductive gel. In some embodiments, the substrate itself can be an adhesive that can hold the IC (or packaged surface mount component (SMC)) in place. Alternatively, the adhesive can be placed on the landing area or on the IC (or SMC). Finally, an encapsulation layer can be placed over the assembly to secure the conductive gel and IC in place.

[0062] In some embodiments according to the inventive principles of this patent disclosure, having very soft / conforming conductors can be beneficial for any of soft interconnect attachment, direct die attach, direct IC attach, and / or soft interconnect COB (chip-on-board) processes. In some embodiments, this can be achieved by using a conductive gel (e.g., a gallium-indium-tin alloy doped with oxides and micron-sized particles to control viscosity). In some embodiments, this technique can be used with other conformal conductors capable of forming low-impedance contacts with metal layers.

[0063] In some other embodiments according to some inventive principles of this patent disclosure, a gasket made of a material such as EPDM (ethylene propylene diene monomer) can have a deformable conductor pattern arranged to sense gasket properties. Because connecting electrical contacts to EPDM can be relatively difficult, the deformable conductors can be coupled via a continuous interconnect between the EPDM gasket and another material such as TPU, which can be a good substrate for electrical contacts. Thus, the sensing circuit can be connected to the contacts on the TPU substrate while still providing a good electrical connection to the deformable conductor pattern in or on the EPDM gasket.

[0064] Figure 10 is a cross-sectional view of another embodiment of a structure having continuous interconnections between different materials according to some inventive principles of this patent disclosure. Figure 10 An embodiment may include a pattern of conductive material 30 formed on a first substrate 32. The first substrate 32 may be attached to a second substrate 34, which may have traces 36 of a deformable conductor, such as a conductive gel. A sealant 38 may cover the second substrate 34 and the traces 36. Vias 41 and 43 passing through the first and second substrates 32, 34, respectively, may allow the deformable conductor to form a continuous interconnect 40 between the pattern of conductive material 30 and the traces 36 on the second substrate 34. Figure 10 Any or all of the layers shown may have one or more different properties, and the use of functional materials such as conductive gel for continuous interconnects 40 and / or traces 36 may allow Figure 10 The illustrated assembly is capable of being manufactured and / or operated while eliminating or reducing problems associated with material fatigue, material creep, current interaction between multiple conductors, and the like.

[0065] Figure 10 The illustrated embodiment can be used for bioelectric sensors such as electrocardiograms (ECGs or EKGs) and electromyograms (EMGs). In such an embodiment, the conductive material 30 can be made of conductive silicone, copper cladding, or other materials suitable for implementing electrodes suitable for contact with the patient's body. The first substrate 32 and the second substrate 34 can be made of, for example, a material that is rigid enough to support one or more electronic components but flexible enough to conform comfortably to the patient's body. Examples include TPU, polyamide, thermosetting epoxies, thermosetting plastics, and the like.

[0066] In some exemplary embodiments, the conductive material 30 may be implemented as conductive silicone, which has good tolerance for skin contact, while the second substrate 34 may be implemented as epoxy to form a base for electronic components and / or other trace layers for a circuit board. The first substrate 32 may be implemented as TPU, which may protect the patient from contact with the epoxy substrate 34, which may be irritating to some patients.

[0067] Although conductive traces 36 are shown on the bottom of second substrate 34 , in some embodiments, conductive traces 36 may pass through second substrate 34 , which may be used as, for example, an in-place stencil to form traces 36 that may be enclosed between first substrate 32 and encapsulant 38 .

[0068] Some embodiments may include additional substrate layers with additional vias, traces, etc. to form functional circuits with one or more electrical and / or electronic components.

[0069] In some embodiments, Figure 10The illustrated structure may include an interface 44 to connect the assembly to one or more other devices. For example, in some embodiments, the conductive traces 36 may transition to one or more terminals to couple the assembly to a cable or other conductive device, such as to read data from a sensor in which the assembly is integrated. In other embodiments, the interface 44 may transition to another heterogeneous junction (e.g., Figure 4 The heterojunction shown in FIG. 4A ) transitions to a relatively high elongation conductive component, thereby connecting the component to other devices.

[0070] In some embodiments, Figure 10 One or more of the substrates shown may be implemented as a fabric layer, or a fabric layer may be added as an additional layer. For example, in the case of a bioelectric sensor, such a fabric layer may be included to provide patient comfort. Furthermore, additionally or alternatively, such a fabric layer may be used to integrate the component into a piece of clothing or apparel, or into other wearable devices such as a brace. Furthermore, such as Figure 10 The various components shown may be integrated into a garment or apparel or other wearable device having one or more flexible and / or stretchable substrates to form electrical and / or electronic interconnections between the components.

[0071] Figure 11 is a cross-sectional view of another example embodiment of a heterostructure according to the present disclosure. Figure 11 The illustrated embodiment may include Figure 4 Similar components to those shown in the embodiment of Figure 11 The embodiment may further include a third substrate, substrate C (166) forming a second joint with substrate B (112). Traces 168, traces and / or pads 170, vias 172 and / or vias 174 may continue the continuous interconnect formed by the interconnect medium 114 through traces 122 and / or pads 124, vias 116, and traces 118 and / or pads 120. Another sealant C (176) may encapsulate the interconnect portion in or on substrate C. In some embodiments, any of sealants A, B, and / or C may be formed as a single layer.

[0072] In some embodiments, Figure 11The structure shown in FIG. 1 can be used, for example, in applications where it can provide a continuous functional interconnection between components X and Y. For example, component X can be implemented as a sensor, display, actuator, and / or any other type of component that can be carried on substrate A. Substrate A can be implemented, for example, using a material that is relatively rigid enough to support the sensor, display, actuator, etc. of component X (e.g., as a medical or other biosensor, an industrial sensor, etc.), yet still flexible and / or stretchable enough to conform to the body of a subject, a piece of industrial equipment, a parachute, clothing, or other soft item. Substrate A can then transition to substrate B, which can be implemented, for example, as a relatively more flexible and / or stretchable (e.g., high elongation) material that can conduct one or more signals and / or function as a sensor while extending a distance to component Y. For example, substrate B can be sewn, bonded, or otherwise attached to clothing, parachute cord, piping, conduit, cable, or the like. Substrate B can then transition to substrate C, which can be implemented, for example, with a relatively rigid material (such as a fiberglass or polyamide circuit board) that can carry a data collection and / or processing unit that can display data received from component X, send data to be displayed by component X, control one or more sub-components in component X, etc.

[0073] Therefore, in some embodiments, depending on implementation details, components (such as Figure 11 The assembly shown) can provide a complete end-to-end interconnect solution between two components, which can span multiple joints between heterogeneous materials, which in turn can span multiple environments when utilizing one continuous interconnect.

[0074] Can be used to make continuous interconnections between heterogeneous materials (such as in Figure 10 and Figure 11 Some of the techniques (such as those shown in ) include those disclosed in the above-mentioned U.S. Patent Application Publication No. 2020 / 0066628, which is incorporated by reference, and which discloses methods for directly attaching surface mount components to through-holes filled with conductive gel and other interconnect media, as well as template printing methods for manufacturing multi-layer PCBs compatible with conductive gel and other interconnect media.

[0075] The embodiments disclosed herein may be described in the context of various implementation details, but the principles of this disclosure are not limited to these or any other specific details. Some functionality has been described as being implemented by certain components, but in other embodiments, functionality may be distributed across different systems and components in different locations and with various user interfaces. Certain embodiments have been described as having specific components, processes, steps, combinations thereof, etc., but these terms may also include embodiments in which a specific process, step, combination thereof, etc. may be implemented using multiple components, processes, steps, combinations thereof, and / or the like, or in which multiple processes, steps, combinations thereof, and / or the like may be integrated into a single process, step, combination thereof, and / or the like. Reference to a component or element may refer to only a portion of a component or element. Terms such as "first" and "second" may be used in this disclosure and claims solely to distinguish the items they modify and may not indicate any spatial or temporal order unless otherwise apparent from the context. Reference to a first item does not imply the existence of a second item. Furthermore, in accordance with the inventive principles of this patent disclosure, the various details and embodiments described above may be combined to create additional embodiments.

[0076] Since the inventive concepts of this patent disclosure may be modified in arrangement and detail without departing from the inventive concept, such changes and modifications are considered to fall within the purview of the appended claims.

Claims

1. A deformable electronic device comprising: substrate layer; Encapsulation layer; a trace formed of a deformable conductor disposed between the substrate layer and the encapsulation layer; a pattern of conductive material; as well as A continuous interconnect electrically couples the trace and the pattern of conductive material, wherein the continuous interconnect includes the deformable conductor.

2. The deformable electronic device according to claim 1, wherein: The deformable conductor is a conductive gel. 3 . The deformable electronic device according to claim 2 , further comprising a template layer located between the packaging layer and the substrate layer. 4 . The deformable electronic device of claim 3 , wherein the template layer at least partially comprises the deformable conductor.

5. The deformable electronic device of claim 1, wherein the pattern of conductive material is located on the substrate layer. The deformable electronic device according to claim 1 , wherein the conductive material is composed of conductive silicone.

7. A deformable electronic device according to claim 6, wherein the pattern of conductive material forms an electrode.

8. The deformable electronic device according to claim 7, wherein the electrode is an electrode for a bioelectric sensor.

9. The deformable electronic device of claim 1 , further comprising a through hole extending through the substrate layer, wherein The through-holes form the continuous interconnection.

10. The deformable electronic device according to claim 1, wherein: The deformable conductor includes a eutectic gallium alloy. The deformable electronic device according to claim 1 , wherein the substrate layer and the encapsulation layer are composed of common materials.

12. The deformable electronic device of claim 11, comprising an additional layer, wherein: The additional layer is a fabric that is integrated into the wearable device.

13. A deformable electronic device comprising: a first layer made of a first material; a trace formed of a deformable conductor disposed on the first layer; a second layer made of a second material; as well as A continuous interconnect couples the trace point to the second layer, wherein the continuous interconnect includes the deformable conductor. 14 . The deformable electronic device of claim 13 , further comprising an encapsulation layer configured to encapsulate traces between the first layer and the encapsulation layer.

15. The deformable electronic device according to claim 13, wherein: The deformable conductor is composed of conductive gel.

16. The deformable electronic device according to claim 13, wherein: The first material is an insulating material, and the second material is a conductive material.

17. The deformable electronic device according to claim 13, wherein: The deformable conductor also forms a via extending from the trace to the second layer, and the continuous interconnect is located at the via.

18. The deformable electronic device according to claim 17, further comprising a third layer, wherein the third layer is made of a third material, The trace is disposed between the first layer and the third layer, and the via extends between the first layer and the second layer.

19. The deformable electronic device according to claim 18, wherein: The third layer is the fabric integrated into the wearable device.

20. A deformable electronic device comprising: substrate layer; an electronic component located on the first surface of the substrate layer; a trace formed of a deformable conductor disposed on a second surface of the substrate layer opposite the first surface; an encapsulation layer encapsulating the deformable conductor of the substrate layer; as well as A continuous interconnect electrically couples the trace and the electronic component, the continuous interconnect being formed from the deformable conductor.

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