Conductive device and preparation method thereof
By stacking liquid metal and solid metal structures in the conductive device, the flowability of liquid metal is used to increase the stretching amount of the conductive device, the problem of existing wires breaking under low strain is solved, and the conductive performance and stability are improved.
Patent Information
- Application Number
- CN202411303279.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-18
- Publication Date
- 2024-12-20
AI Technical Summary
The existing stretchable conductors are not matched by the mechanical properties of rigid metal conductive fillers and resins under low strain, resulting in irreversible cracks, resulting in failure of conductive circuit connections, affecting the preparation of electronic devices in the mold.
The conductive structure with liquid metal elements and the conductive structure with solid metal elements are laminated, and the flowability of liquid metals is used to increase the stretching amount of the conductive device to ensure that the conductive lines continue to crack under low strain.
It improves the stability and conductivity of the conductive device, ensures that the conductive lines can be effectively stretched by more than 100% during the high-temperature 3D forming process, avoids irreversible cracks, and enhances the reliability of the electronic devices in the mold.
Smart Images
Figure CN119172926A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of conductive technology, and in particular to a conductive device and a method for preparing the same. Background Art
[0002] In-mold electronics (IME) is a combination of traditional in-mold decoration technology and flexible printed circuits, which can produce 3D shapes with embedded circuits of varying complexity. The stretchability of printed wires during high-temperature 3D molding is the key to the successful preparation of in-mold electronics (IME) devices.
[0003] In the related art, the stretchable conductor scheme often produces irreversible cracks at low strain (<100%) due to the mismatch between the mechanical properties of the rigid metal conductive filler and the resin, resulting in failure of the conductive circuit connection.
[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention
[0005] The purpose of the present disclosure is to overcome the deficiencies of the prior art and provide a conductive device and a preparation method thereof, which can improve circuit stability.
[0006] According to one aspect of the present disclosure, there is provided a conductive device having:
[0007] A first encapsulation layer;
[0008] A second encapsulation layer;
[0009] A conductive unit; the conductive unit is located between the first packaging layer and the second packaging layer; the conductive device has a non-flat area, and the conductive unit has a first conductive structure and a second conductive structure stacked in the non-flat area; the second conductive structure covers the first conductive structure; the first conductive structure has at least one first metal element, and the first metal element is a solid metal element; the second conductive structure has at least one second metal element, and the second metal element is a liquid metal element.
[0010] In one embodiment of the present disclosure, the conductive device further comprises electronic components; the conductive device comprises a flat region and a non-flat region;
[0011] The first conductive structure extends from the uneven area to the flat area, and the second conductive structure covers the first conductive structure;
[0012] The electronic component is disposed on a surface of the second conductive structure away from the first conductive structure, and is electrically connected to the second conductive structure.
[0013] In one embodiment of the present disclosure, the first conductive structure contains a first metal element, which is gold; the second conductive structure contains three second metal elements, which are gallium, indium, and tin, respectively.
[0014] In one embodiment of the present disclosure, the first conductive structure has at least one first metal element therein, and the first conductive structure also has at least one second metal element therein.
[0015] In one embodiment of the present disclosure, the second conductive structure has three second metal elements, and the three second metal elements are gallium, indium, and tin;
[0016] The first conductive structure has at least one first metal element therein, at least one of the first metal elements is silver or copper, and the first conductive structure has at least one second metal element therein, the second metal element is gallium.
[0017] In an embodiment of the present disclosure, in the second conductive structure, the mass percentages of gallium, indium, and tin are 65% to 100%: 0% to 30%: 0% to 20%.
[0018] In an embodiment of the present disclosure, in the second conductive structure, the mass percentages of gallium, indium, and tin are 68.5%:21.5%:10%.
[0019] In one embodiment of the present disclosure, the thickness of the second conductive structure is 1 μm to 1 mm; the thickness of the first conductive structure is 50 nm to 5 μm.
[0020] According to another aspect of the present disclosure, a method for preparing a conductive device is provided, comprising the following steps:
[0021] A conductive device is provided, the conductive device comprising:
[0022] A first encapsulation layer;
[0023] A second encapsulation layer;
[0024] A conductive unit; the conductive unit is located between the first packaging layer and the second packaging layer; the conductive device has a non-flat area, and the conductive unit has a first conductive structure and a second conductive structure stacked in the non-flat area; the second conductive structure covers the first conductive structure; the first conductive structure has at least one first metal element, and the first metal element is a solid metal element; the second conductive structure has at least one second metal element, and the second metal element is a liquid metal element.
[0025] In one embodiment of the present disclosure, the following steps are included:
[0026] forming a patterned first metal layer on the first encapsulation layer;
[0027] Using the difference in wettability between the liquid metal element on the first packaging layer and the first metal layer, a second metal layer is formed on the first metal layer, thereby obtaining a first packaging layer having a first conductive structure and a second conductive structure;
[0028] Bending the first packaging layer having the first conductive structure and the second conductive structure to form a non-flat area;
[0029] A second encapsulation layer is formed on the second conductive structure.
[0030] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.
[0032] Figure 1 It is a partial structural schematic diagram of a conductive device in one embodiment of the present disclosure.
[0033] Figure 2 It is a partial structural schematic diagram of a conductive device in one embodiment of the present disclosure.
[0034] Figure 3 This is a schematic diagram of the manufacturing process structure of a conductive device in one embodiment of the present disclosure.
[0035] Figure 4 This is a schematic diagram of the manufacturing process structure of a conductive device in one embodiment of the present disclosure.
[0036] Figure 5This is a schematic diagram of the manufacturing process structure of a conductive device in one embodiment of the present disclosure.
[0037] Figure 6 This is a schematic diagram of the manufacturing process structure of a conductive device in one embodiment of the present disclosure.
[0038] Figure 7 This is a schematic diagram of the manufacturing process structure of a conductive device in one embodiment of the present disclosure.
[0039] Figure 8 This is a schematic diagram of the manufacturing process structure of a conductive device in one embodiment of the present disclosure.
[0040] Fig. 9 In one embodiment of the present disclosure, the resistance change of the conductive device changes with the tensile strain. DETAILED DESCRIPTION
[0041] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.
[0042] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of the illustration to another component, these terms are used in this specification only for convenience, such as according to the orientation of the examples described in the drawings. It is understood that if the device of the illustration is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through another structure.
[0043] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second", etc. are used merely as labels and are not intended to limit the quantity of their objects.
[0044] Structure A is located on the side of structure B that is away from structure C. It can be understood that structure A is formed on the side of structure B that is away from structure C.
[0045] In the present application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.
[0046] In-mold electronics (IME) is a combination of traditional in-mold injection molding decoration technology and flexible printed circuits. It can produce 3D shapes with embedded circuits of varying complexity. The main processes of in-mold electronics (IME) include the following steps: (1) printing circuits on the film, (2) installing electronic components on the film, (3) hot pressing / blister molding the film into a 3D shape, and (4) insert injection molding into a structural part. This technology achieves lightweight products by integrating integrated circuits into decorative parts, and has both decorative aesthetics and electronic functionality. It can be widely used in many fields such as automobiles, home appliances, consumer electronics, and medical devices.
[0047] From the above-mentioned in-mold electronics (IME) process steps, it can be seen that the stretchability of printed wires during high-temperature 3D molding is the key to ensuring the successful preparation of in-mold electronics (IME) devices.
[0048] Existing stretchable conductor solutions are mainly based on stretchable silver paste, which is mainly composed of rigid micro-nano silver sheets or silver powder conductive fillers and high-temperature stretchable resin. Due to the mismatch between the mechanical properties of rigid metal conductive fillers and resins, irreversible cracks often occur at low strains (<100%), resulting in failure of conductive line connections. Therefore, developing conductor materials with higher tensile strains is a major challenge facing the field of in-mold electronics.
[0049] In order to solve at least one of the above problems, the present disclosure optimizes the structure of the conductive device IM (in-mold electronics (IME)), adopts a conductive structure with liquid metal elements and a conductive structure with solid metal elements in a stacked manner (a liquid conductive layer with composite flow on a solid metal conductive layer), and utilizes the fluidity of the liquid metal to make the conductive device IM have a high stretchability (>100%). In this way, the problem of irreversible cracks in the conductive device IM under low strain, which leads to failure of the conductive line connection, can be improved, thereby improving the stability and conductive performance of the conductive device IM.
[0050] Specifically, in one embodiment of the present disclosure, a conductive device IM is provided, see Figure 1-Figure 8, the conductive device IM includes a first encapsulation layer FL1 and a second encapsulation layer FL2, and a conductive unit MC located between the first encapsulation layer FL1 and the second encapsulation layer FL2. The conductive device IM has a non-flat area, and the conductive unit MC has a first conductive structure MCL1 and a second conductive structure MCL2 stacked in the non-flat area; the second conductive structure MCL2 covers the first conductive structure MCL1; the first conductive structure MCL1 has at least one first metal element, and the first metal element is a solid metal element; the second conductive structure MCL2 has at least one second metal element, and the second metal element is a liquid metal element. In the present disclosure, by compounding a layer of a second conductive structure MCL2 having flow characteristics at room temperature on the first conductive structure MCL1, the fluidity of the liquid metal in the second conductive structure MCL2 is used to make the conductive device IM have a high stretching amount (>100%), so that the conductive device IM can improve the problem of irreversible cracks under low strain, resulting in failure of the conductive line connection, and improve the stability and conductive performance of the conductive device IM. In an example, the second conductive structure MCL2 has flow characteristics at 26°C. In another example, the second conductive structure MCL2 has the flow characteristic at 28° C. In another example, the second conductive structure MCL2 has the flow characteristic at 25° C. In other examples, other temperatures are also possible.
[0051] It is understood that in this example, see Figure 2 and Figure 7 ( Figure 2 for Figure 1 ), the conductive unit MC has a first conductive structure MCL1 and a second conductive structure MCL2; the conductive device IM has a non-planar area. In other words, see Figure 7 , the conductive device IM is not a planar structure. In this example, the conductive device IM can be formed into a 3D shape by hot pressing / blister molding of a thin film, and the 3D shape can be expanded from the first packaging layer FL1 to the second packaging layer FL2, thereby forming a non-flat area. At this time, the first conductive structure MCL1 is arranged on the first packaging layer FL1, and the second conductive structure MCL2 is arranged on the side of the first conductive structure MCL1 away from the first packaging layer FL1. In another example, the conductive device IM can be formed into a 3D shape by hot pressing / blister molding of a thin film, and the 3D shape can be expanded from the second packaging layer FL2 to the first packaging layer FL1, thereby forming a non-flat area. At this time, the first conductive structure MCL1 is arranged on the second packaging layer FL2, and the second conductive structure MCL2 is arranged on the side of the first conductive structure MCL1 away from the second packaging layer FL2.
[0052] Based on the above structure, the present disclosure also provides a method for preparing a conductive device IM, comprising the following steps: providing a conductive device IM, the conductive device IM having:
[0053] A first encapsulation layer FL1;
[0054] A second encapsulation layer FL2;
[0055] Conductive unit MC; the conductive unit MC is located between the first packaging layer FL1 and the second packaging layer FL2; the conductive device IM has a non-flat area, and the conductive unit MC has a first conductive structure MCL1 and a second conductive structure MCL2 stacked in the non-flat area; the second conductive structure MCL2 covers the first conductive structure MCL1; the first conductive structure MCL1 has at least one first metal element, and the first metal element is a solid metal element; the second conductive structure MCL2 has at least one second metal element, and the second metal element is a liquid metal element.
[0056] Specific:
[0057] In one embodiment of the present disclosure, the first encapsulation layer FL1 and the second encapsulation layer FL2 are insulating materials. In one example, the material of the first encapsulation layer FL1 may be plastic, and the material of the second encapsulation layer FL2 may be plastic. For example, the material of the first encapsulation layer FL1 may be PET (polyethylene glycol terephthalate, PET for short). The material of the second encapsulation layer FL2 may be PET (polyethylene glycol terephthalate, PET for short).
[0058] In one embodiment of the present disclosure, the conductive device IM has a flat region and a non-flat region. In one example, the flat region may surround the non-flat region.
[0059] In one embodiment of the present disclosure, the conductive unit MC is a double-layer conductive structure (a first conductive structure MCL1 and a second conductive structure MCL2 stacked). And at least in the non-flat area of the conductive device IM, the second conductive structure MCL2 covers the first conductive structure MCL1, so that it is equivalent to setting a second conductive structure MCL2 of a layer of liquid metal material on the first conductive structure MCL1. Due to its high tensile performance, the second conductive structure MCL2 (liquid metal layer) has high stretchability (tensile strain is not less than 100%) during the high-temperature 3D molding process of the conductive device IM. The second conductive structure MCL2 will completely and continuously cover the stretching area of the first conductive structure MCL1, avoiding the problem of line connection failure caused by the conductive unit MC breaking during stretching. In one example, the first conductive structure MCL1 extends to the flat area, and the second conductive structure MCL2 extends to the flat area and covers the first conductive structure MCL1. It can be understood that the second conductive structure MCL2 covers the first conductive structure MCL1 in the flat area and the non-flat area. In other words, all areas of the first conductive structure MCL1 away from the first packaging layer FL1 are covered with the second conductive structure MCL2. The second conductive structure MCL2 has fluid properties at room temperature. In this way, the continuity of the conductive unit MC can be achieved to the maximum extent, ensuring the stability of the line connection.
[0060] In one embodiment of the present disclosure, the conductive device IM further has an electronic component EC. The electronic component EC is arranged on the surface of the second conductive structure MCL2 away from the first conductive structure MCL1, and the second conductive structure MCL2 of the electronic component EC is electrically connected. In this way, an in-mold electronic structure is formed. The present disclosure arranges the electronic component EC on the second conductive structure MCL2, which can achieve stable electrical conduction between the electronic component EC and the conductive unit MC, thereby improving the performance of the entire conductive device IM. In this example, the number of electronic components EC is set according to demand. The number of electronic components EC can be one or more, which is not limited here. In this example, the conductive device IM of this structure can be widely used in many fields such as automobiles, home appliances, consumer electronics and medical devices.
[0061] In one embodiment of the present disclosure, the thickness of the first conductive structure MCL1 may be 50nm to 5μm, and the thickness of the second conductive structure MCL2 may be 1μm to 1mm. For example, the thickness of the first conductive structure MCL1 may be 50nm, and the thickness of the second conductive structure MCL2 may be 1μm. For another example, the thickness of the first conductive structure MCL1 may be 1μm, and the thickness of the second conductive structure MCL2 may be 130μm. For another example, the thickness of the first conductive structure MCL1 may be 2μm, and the thickness of the second conductive structure MCL2 may be 300μm. For another example, the thickness of the first conductive structure MCL1 may be 3μm, and the thickness of the second conductive structure MCL2 may be 550μm. For another example, the thickness of the first conductive structure MCL1 may be 4μm, and the thickness of the second conductive structure MCL2 may be 750μm. For another example, the thickness of the first conductive structure MCL1 may be 5μm, and the thickness of the second conductive structure MCL2 may be 1mm. In this way, the thickness of the second conductive structure MCL2 is relatively thick, and the material of the second conductive structure MCL2 is more than that of the first conductive structure MCL1, which can further maintain good conductivity after the conductive device IM completes 3D molding. At the same time, if the first conductive structure MCL1 can react with the second conductive structure MCL2, after the reaction is completed, a part of the liquid metal can still remain to maintain the flow characteristics, that is, the second conductive structure MCL2 is always present, further ensuring the conductive continuity of the conductive device IM.
[0062] In one embodiment of the present disclosure, the first conductive structure MCL1 has at least one first metal element, and the second conductive structure MCL2 has at least one second metal element, wherein the first metal element is a solid metal element and the second metal element is a liquid metal element, so that both the first conductive structure MCL1 and the second conductive structure MCL2 are conductive. It can be understood that the liquid metal element should be a non-toxic metal. In one example, the second metal element (liquid metal element) can be a metal element such as gallium, tin, indium, etc. In other examples, the second metal element (liquid metal element) can also be other non-toxic liquid metal elements (liquid metal is a general term for seventeen metals whose melting point does not exceed the melting temperature of aluminum (660.37°C), and many alloys are also liquid at room temperature or even at very low temperatures. For example, it is liquid at 26°C; for example, it is liquid at 25°C; in other examples, it can also be other normal temperatures).
[0063] In the first example of the present disclosure, the first metal element does not react with the second metal element. For example, the first metal element in the first conductive structure MCL1 may be gold (Au), and a second metal element in the second conductive structure MCL2 may be gallium (Ga). In one example, the second conductive structure MCL2 may be a gallium-based alloy. In this way, gallium is a liquid substance with the highest electrical and thermal conductivity at room temperature. Therefore, the second conductive structure MCL2 uses gallium or a gallium-based alloy, and the conductive performance is optimal. In one example, the liquid metal element in the gallium-based alloy may include three liquid metal elements: gallium (Ga), indium (In), and tin (Sn).
[0064] In this example, in the gallium-based alloy, the mass percentages of gallium, indium, and tin are 65% to 100%, 0% to 30%, and 0% to 20%, respectively. It is understandable that the mass percentage of gallium is 65% to 100%, the mass percentage of indium is 0% to 30%, and the mass percentage of tin can be 0% to 20%. For example, the mass percentage of gallium is 65%, the mass percentage of indium is 20%, and the mass percentage of tin can be 15%. For another example, the mass percentage of gallium is 68.5%, the mass percentage of indium is 21.5%, and the mass percentage of tin can be 10%. For another example, the mass percentage of gallium is 73%, the mass percentage of indium is 17%, and the mass percentage of tin can be 10%. For another example, the mass percentage of gallium is 85%, the mass percentage of indium is 9%, and the mass percentage of tin can be 6%. For another example, the mass percentage of gallium is 100%, the mass percentage of indium is 0%, and the mass percentage of tin can be 0%.
[0065] In one embodiment of the present disclosure, the first conductive structure MCL1 may be formed by compounding a metal filler having a first metal element and a thermoplastic resin, and the first conductive structure MCL1 forms a conductive path by mutual contact between the metal fillers.
[0066] Based on the above structure, the conductive device IM in the embodiment of the present disclosure can be prepared in the following manner:
[0067] S1. See Figure 3 and Figure 4 , preparing a first conductive substrate;
[0068] The patterned stainless steel sheet mask is fixed on the first packaging layer FL1 (PET film) and placed in a magnetron sputtering device; a first metal layer (gold layer) of a patterned conductive unit MC is prepared on the PET film by magnetron sputtering a gold (Au) target, wherein the sputtering power is 150-250 W and the time is 5-15 minutes, to obtain a first conductive substrate; for example, in this example, the sputtering power is 150 W and the time is 15 minutes; for another example, in this example, the sputtering power is 200 W and the time is 10 minutes; for another example, in this example, the sputtering power is 250 W and the time is 5 minutes;
[0069] S2, see Figure 5 , utilizing the difference in wettability of the liquid metal on the first metal layer and the first packaging layer FL1, coating a second metal layer on the first metal layer to obtain a second conductive substrate;
[0070] The entire first conductive substrate is immersed in a diluted sodium hydroxide solution (0.3wt%-0.9wt%), and the Ga-In-Sn alloy droplets (second metal layer) are rolled on the first conductive substrate. Due to the difference in wettability of the liquid metal on the first packaging layer FL1 and the first metal layer, the Ga-In-Sn alloy droplets (second metal layer) will be selectively coated on the first metal layer to form a second conductive substrate, wherein the first metal layer is the first conductive structure MCL1, and the second metal layer is the second conductive structure MCL2. For example, in this example, it can be a 0.6wt% sodium hydroxide solution; for another example, in this example, it can be a 0.4wt% sodium hydroxide solution; for another example, in this example, it can be a 0.8wt% sodium hydroxide solution; for another example, in this example, it can be a 0.9wt% sodium hydroxide solution;
[0071] S3, cleaning and drying the second conductive substrate;
[0072] The second conductive substrate is taken out from the sodium hydroxide solution, rinsed with deionized water, and dried; in one example, it can be dried in an oven at 50°C-70°C for 15-25 minutes; for example, it can be dried in an oven at 50°C for 25 minutes; for another example, it can be dried in an oven at 60°C for 20 minutes; for another example, it can be dried in an oven at 65°C for 12 minutes; for another example, it can be dried in an oven at 70°C for 15 minutes;
[0073] S4. See Figure 6 , installing electronic components EC to form a third conductive substrate;
[0074] Mounting the electronic component EC on the second conductive structure MCL2 of the dried second conductive substrate to form a third conductive substrate, wherein the conductive unit MC (the first conductive structure MCL1 and the second conductive structure MCL2) and the electronic component EC form a functional circuit;
[0075] S5. See Figure 7 , hot pressing / blister forming the third conductive substrate into a 3D shape;
[0076] Placing the third conductive substrate in a hot pressing or blister forming cavity, and after the third conductive substrate is heated to a softened state, the third conductive substrate is hot pressed or blister formed into a preset 3D shape;
[0077] S6. See Figure 8 , injection molding to form a conductive device IM;
[0078] The third conductive substrate with a 3D shape is placed in the injection molding cavity, and the insert is injection molded into a structural part to form a second packaging layer FL2 covering the third conductive substrate. The functional circuit is embedded between the second packaging layer FL2 and the first packaging layer FL1, thereby obtaining a conductive device IM with a lightweight structure and integrated functions.
[0079] In the second example of the present disclosure, at least one first metal element reacts with at least one second metal, so that at least one first metal element and at least one second metal element are simultaneously present in the first conductive structure MCL1, and the second metal element in the first conductive structure MCL1 is the same as the second metal element in the second conductive structure MCL2. For example, the second metal element reacting with the first metal element may be gallium, and one of the first metal elements may be silver (Ag) or copper (Cu). For example, one of the first metal elements may be silver or copper; the second conductive structure MCL2 may be a gallium-based alloy, and the second metal element may include gallium, indium, and tin.
[0080] In this example, in the gallium-based alloy, the mass percentages of gallium, indium, and tin are 65% to 100%, 0% to 30%, and 0% to 20%, respectively. It is understandable that the mass percentage of gallium is 65% to 100%, the mass percentage of indium is 0% to 30%, and the mass percentage of tin can be 0% to 20%. For example, the mass percentage of gallium is 65%, the mass percentage of indium is 20%, and the mass percentage of tin can be 15%. For another example, the mass percentage of gallium is 68.5%, the mass percentage of indium is 21.5%, and the mass percentage of tin can be 10%. For another example, the mass percentage of gallium is 73%, the mass percentage of indium is 17%, and the mass percentage of tin can be 10%. For another example, the mass percentage of gallium is 85%, the mass percentage of indium is 9%, and the mass percentage of tin can be 6%. For another example, the mass percentage of gallium is 100%, the mass percentage of indium is 0%, and the mass percentage of tin can be 0%.
[0081] In one embodiment of the present disclosure, taking copper as the first metal element as an example, the conductive device IM in the embodiment of the present disclosure can be prepared by the following method:
[0082] S1. See Figure 3 and Figure 4 , preparing a first conductive substrate;
[0083] A patterned stainless steel sheet mask is fixed on the first packaging layer FL1 (PET film) and placed in a magnetron sputtering device; a first metal layer (copper layer) of a patterned conductive unit MC is prepared on the PET film by using a magnetron sputtering copper target, with a sputtering power of 50-150 W and a time of 5-15 minutes to obtain a first conductive substrate; for example, in this example, the sputtering power is 50 W and the time is 15 minutes; for another example, in this example, the sputtering power is 100 W and the time is 10 minutes; for another example, in this example, the sputtering power is 150 W and the time is 5 minutes; wherein the first metal layer can be a composite of a metal filler having a first metal element and a thermoplastic resin, and the first metal layer forms a conductive path by mutual contact between the metal fillers;
[0084] S2, see Figure 5 , utilizing the difference in wettability of the liquid metal on the first metal layer and the first packaging layer FL1, coating a second metal layer on the first metal layer to obtain a second conductive substrate;
[0085] Immerse the entire first conductive substrate in a diluted sodium hydroxide solution (0.3wt%-0.9wt%). Roll the Ga-In-Sn alloy droplets (second metal layer) on the first conductive substrate. Due to the difference in wettability between the Ga-In-Sn alloy droplets (second metal layer) on the first packaging layer FL1 and the first metal layer (copper layer), the Ga-In-Sn alloy droplets (second metal layer) will be selectively coated on the first metal layer (copper layer) to form a second conductive substrate. For example, in this example, it can be a 0.6wt% sodium hydroxide solution; for another example, in this example, it can be a 0.4wt% sodium hydroxide solution; for another example, in this example, it can be a 0.8wt% sodium hydroxide solution; for another example, in this example, it can be a 0.9wt% sodium hydroxide solution;
[0086] S3, cleaning and drying the second conductive substrate;
[0087] The second conductive substrate is taken out from the sodium hydroxide solution, rinsed with deionized water, and dried; due to the gradual alloying reaction between copper and Ga-In-Sn alloy droplets, the copper that finally contacts the Ga-In-Sn alloy droplets gradually dissolves in the Ga-In-Sn alloy droplets to form a Cu2Ga intermetallic compound, the Cu2Ga intermetallic compound is the first conductive structure MCL1, and the remaining Ga-In-Sn alloy droplets coated on the Cu2Ga intermetallic compound are the second conductive structure MCL2; in one example, it can be dried in an oven at 50°C-70°C for 15-25 minutes; for example, it can be dried in an oven at 50°C for 25 minutes; for another example, it can be dried in an oven at 60°C for 20 minutes; for another example, it can be dried in an oven at 65°C for 12 minutes, and for another example, it can be dried in an oven at 70°C for 15 minutes;
[0088] S4. See Figure 6 , installing electronic components EC to form a third conductive substrate;
[0089] The electronic component EC is mounted on the second conductive structure MCL2 of the dried second conductive substrate to form a third conductive substrate, wherein the conductive unit MC (the first conductive structure MCL1 and the second conductive structure MCL2) and the electronic component EC form a functional circuit;
[0090] S5. See Figure 7 , hot pressing / blister forming the third conductive substrate into a 3D shape;
[0091] Placing the third conductive substrate in a hot pressing or blister forming cavity, and after the third conductive substrate is heated to a softened state, the third conductive substrate is hot pressed or blister formed into a preset 3D shape;
[0092] S6. See Figure 8 , injection molding to form a conductive device IM;
[0093] The third conductive substrate with a 3D shape is placed in the injection molding cavity, and the insert is injection molded into a structural part to form a second packaging layer FL2 covering the third conductive substrate. The functional circuit is embedded between the second packaging layer FL2 and the first packaging layer FL1, thereby obtaining a conductive device IM with a lightweight structure and integrated functions.
[0094] In another embodiment of the present disclosure, taking silver as the first metal element as an example, the conductive device IM in the embodiment of the present disclosure can be prepared by the following method:
[0095] S1. See Figure 3 and Figure 4 , preparing a first conductive substrate;
[0096] The patterned stainless steel sheet mask is fixed on the first packaging layer FL1 (PET film), and placed in a magnetron sputtering device; a first metal layer (silver layer) of a patterned conductive unit MC is prepared on the PET film by using a magnetron sputtering silver target, with a sputtering power of 150-250 W and a time of 5-15 minutes, to obtain a first conductive substrate; for example, in this example, the sputtering power is 150 W and the time is 15 minutes; for another example, in this example, the sputtering power is 200 W and the time is 10 minutes; for another example, in this example, the sputtering power is 250 W and the time is 5 minutes;
[0097] S2, see Figure 5 , utilizing the difference in wettability of the liquid metal on the first metal layer and the first packaging layer FL1, coating a second metal layer on the first metal layer to obtain a second conductive substrate;
[0098] Immerse the entire first conductive substrate in a diluted sodium hydroxide solution (0.3wt%-0.9wt%). Roll the Ga-In-Sn alloy droplets (second metal layer) on the first conductive substrate. Due to the difference in wettability between the Ga-In-Sn alloy droplets on the first encapsulation layer FL1 and the silver layer, the Ga-In-Sn alloy droplets will be selectively coated on the silver layer to form a second conductive substrate. For example, in this example, it can be a 0.6wt% sodium hydroxide solution; for another example, in this example, it can be a 0.4wt% sodium hydroxide solution; for another example, in this example, it can be a 0.8wt% sodium hydroxide solution; for another example, in this example, it can be a 0.9wt% sodium hydroxide solution;
[0099] S3, cleaning and drying the second conductive substrate;
[0100] The second conductive substrate is taken out from the sodium hydroxide solution, and the second conductive substrate is rinsed with deionized water and dried; due to the gradual alloying reaction between silver and Ga-In-Sn alloy droplets, the silver is gradually dissolved in the Ga-In-Sn alloy droplets to form Ag2Ga, AgIn2, and Ag3Sn intermetallic compounds, and the intermetallic compounds are the first conductive structure MCL1, and the remaining Ga-In-Sn alloy droplets attached to the intermetallic compounds are the second conductive structure MCL2; in one example, it can be dried in an oven at 50°C-70°C for 15-25 minutes; for example, it can be dried in an oven at 50°C for 25 minutes; for another example, it can be dried in an oven at 60°C for 20 minutes; for another example, it can be dried in an oven at 65°C for 12 minutes, and for another example, it can be dried in an oven at 70°C for 15 minutes;
[0101] S4. See Figure 6 , installing electronic components EC to form a third conductive substrate;
[0102] The electronic component EC is mounted on the corresponding position of the dried second conductive substrate to form a third conductive substrate, wherein the conductive unit MC (the first conductive structure MCL1 and the second conductive structure MCL2) and the electronic component EC form a functional circuit;
[0103] S5. See Figure 7 , hot pressing / blister forming the third conductive substrate into a 3D shape;
[0104] Placing the third conductive substrate in a hot pressing or blister forming cavity, and after the third conductive substrate is heated to a softened state, the third conductive substrate is hot pressed or blister formed into a preset 3D shape;
[0105] S6. See Figure 8 , injection molding to form a conductive device IM;
[0106] The third conductive substrate with a 3D shape is placed in the injection molding cavity, and the insert is injection molded into a structural part to form a second packaging layer FL2 covering the third conductive substrate. The functional circuit is embedded between the second packaging layer FL2 and the first packaging layer FL1, thereby obtaining a conductive device IM with a lightweight structure and integrated functions.
[0107] In an example, the thickness of the first conductive structure MCL1 is 2 μm, and the first metal element is silver; the mass percentages of gallium, indium, and tin in the second conductive structure MCL2 are Ga:In:Sn=68.5:21.5:10. Fig. 9 The resistance of the conductive device IM obtained in the experiment changes with the tensile strain, where the abscissa represents the tensile strain rate and the ordinate represents the ratio of the current resistance to the initial resistance; R0 in the figure represents the initial resistance, Fig. 9It can be seen that the flow characteristics of the second conductive structure MCL2 (liquid metal) can maintain the effectiveness of the conductive path of the conductive device IM under high strain (>100%).
[0108] In other examples, the copper layer, silver layer or gold layer may also be prepared by evaporation or a metal paste-based printing process.
[0109] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.
Claims
1. A conductive device, It is characterized in that have: A first encapsulation layer; A second encapsulation layer; Conductive unit; The conductive unit is located between the first encapsulation layer and the second encapsulation layer; the conductive device has a non-planar area, and the conductive unit has a first conductive structure and a second conductive structure stacked in the non-planar area; the second conductive structure covers the first conductive structure; The first conductive structure has at least one first metal element therein, and the first metal element is a solid metal element; The second conductive structure has at least one second metal element therein, and the second metal element is a liquid metal element.
2. The conductive device according to claim 1, It is characterized in that The conductive device also has electronic components; the conductive device has a flat area and a non-flat area; The first conductive structure extends from the uneven area to the flat area, and the second conductive structure covers the first conductive structure; The electronic component is disposed on a surface of the second conductive structure away from the first conductive structure, and is electrically connected to the second conductive structure.
3. The conductive device according to claim 1, It is characterized in that The first conductive structure contains a first metal element, which is gold; the second conductive structure contains three second metal elements, which are gallium, indium, and tin.
4. The conductive device according to claim 1, It is characterized in that The first conductive structure has at least one first metal element therein, and the first conductive structure also has at least one second metal element therein.
5. The conductive device according to claim 4, It is characterized in that The second conductive structure has three second metal elements, the three second metal elements are gallium, indium and tin; The first conductive structure has at least one first metal element therein, at least one of the first metal elements is silver or copper, and the first conductive structure has at least one second metal element therein, the second metal element is gallium.
6. The conductive device according to claim 3 or 5, It is characterized in that In the second conductive structure, the mass percentages of gallium, indium and tin are 65% to 100%: 0% to 30%: 0% to 20%.
7. The conductive device according to claim 6, It is characterized in that In the second conductive structure, the mass percentages of gallium, indium and tin are 68.5%:21.5%:10%.
8. The conductive device according to claim 1, It is characterized in that The thickness of the second conductive structure is 1 μm to 1 mm; the thickness of the first conductive structure is 50 nm to 5 μm.
9. A method for preparing a conductive device, It is characterized in that The following steps are involved: A conductive device is provided, the conductive device comprising: A first encapsulation layer; A second encapsulation layer; Conductive unit; The conductive unit is located between the first encapsulation layer and the second encapsulation layer; the conductive device has a non-planar area, and the conductive unit has a first conductive structure and a second conductive structure stacked in the non-planar area; the second conductive structure covers the first conductive structure; The first conductive structure has at least one first metal element therein, and the first metal element is a solid metal element; The second conductive structure has at least one second metal element therein, and the second metal element is a liquid metal element.
10. The method for preparing the conductive device according to claim 9, It is characterized in that The following steps are involved: forming a patterned first metal layer on the first encapsulation layer; Using the difference in wettability of the liquid metal element on the first packaging layer and the first metal layer, a second metal layer is formed on the first metal layer, thereby obtaining a first packaging layer having a first conductive structure and a second conductive structure; Bending the first packaging layer having the first conductive structure and the second conductive structure to form a non-flat area; A second encapsulation layer is formed on the second conductive structure.