Extensible wiring including liquid metal particles and method for manufacturing same

Abstract

The present invention relates to an extensible composite comprising: an extensible substrate; and liquid metal particles formed in the extensible substrate.

Description

Flexible wiring comprising liquid metal particles and method for manufacturing the same

[0001] The present invention relates to a flexible wiring comprising liquid metal particles and a method for manufacturing the same.

[0002] Stretchable wiring is essential for fabricating stretchable mechanical devices such as wearable electronics, soft robotics, prosthetics, and electronic skin. Common methods for creating stretchable wiring include forming metal wires in a wave shape on a stretchable substrate to prevent breakage during stretching, or mixing conductive materials with stretchable polymers. Furthermore, to be applicable to essential semiconductor components in electronic devices, the wiring must be fabricated using the photolithography process currently used in semiconductor device manufacturing. Furthermore, it must be capable of high-resolution, large-area fabrication, as well as possessing excellent electrical properties.

[0003] However, when creating metal wiring in a wave form, geometric constraints hinder high directivity, and the inherent mechanical properties of the metal itself limit the degree of elongation. Furthermore, while creating stretchable wiring by mixing stretchable polymers with conductive materials can achieve high elongation, it suffers from lower conductivity compared to metal materials and is difficult to utilize in photolithography.

[0004] Therefore, in order to secure high conductivity and high elongation of a stretchable polymer composite at the metal level, research is actively being conducted on a method of fabricating a polymer composite using liquid metal particles and a polymer as a conductive material, and patterning the wiring through a photo process to fabricate a high-resolution, high-elongation, high-conductivity wiring.

[0005] The background technology described above is something that the inventor possessed or acquired in the process of deriving the disclosure of the present application, and cannot necessarily be said to be a publicly known technology disclosed to the general public prior to the present application.

[0006] In order to secure high conductivity and high elongation of the polymer composite at the level of metal, the polymer composite can be manufactured using liquid metal particles and polymers as conductive materials. In the case of gallium indium alloy, which is a representative example of liquid metal, there is no limitation on elongation because it is in a liquid state at room temperature, and it has high conductivity at the level of metal (3.4 x 10 6 It has S / m).

[0007] However, these liquid metals have the disadvantage of being difficult to pattern due to their high surface tension and of being easily washed away. Furthermore, liquid metal particles have an insulating oxide film on their surface, preventing current flow even when the particles are in contact.

[0008] The present invention aims to solve the above-described problem by providing a high-resolution, high-conductivity, high-flexibility wiring board and a method for manufacturing the same.

[0009] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by a person having ordinary skill in the relevant technical field from the description below.

[0010] The stretchable composite of the present invention comprises: a stretchable substrate; and liquid metal particles formed within the stretchable substrate.

[0011] In one embodiment, among the extensible composites, the liquid metal particles may be 50 wt% to 95 wt%.

[0012] In one embodiment, the liquid metal particles may include at least one selected from the group consisting of a gallium-indium alloy, gallium, a gallium-indium-tin alloy, a gallium-indium-silver alloy, and a gallium-indium-copper alloy.

[0013] The stretchable wiring board of the present invention comprises: a stretchable substrate; and a wiring comprising the stretchable composite of claim 1 formed on the stretchable substrate.

[0014] In one embodiment, the stretchable substrate may include at least one selected from the group consisting of polydimethylsiloxane (PDMS), Ecoflex, dragon skin, and poly(styrene-co-butadiene) (SEBS).

[0015] In one embodiment, the thickness of the wiring: diameter of the liquid metal particles may be 1:0.01 to 1:1.

[0016] In one embodiment, the wiring has a conductivity of 10 5 S / m to 10 6 It is S / m and can have an elongation of 50% to 200%.

[0017] According to one embodiment, the wiring may have a resistance change rate of 15% or less when elongated by 50%.

[0018] The method for manufacturing a stretchable wiring board of the present invention comprises the steps of: preparing a substrate having a carbon thin film formed thereon; forming a photosensitive agent on the carbon thin film and patterning it; forming a stretchable composite on the patterned photosensitive agent; removing the patterned photosensitive agent to form a pattern of the stretchable composite; forming a stretchable substrate on the carbon thin film and the stretchable composite to form a stretchable wiring board including a pattern of the stretchable composite; and separating the stretchable wiring board from the substrate and removing the carbon thin film from the stretchable wiring board.

[0019] According to one embodiment, the step of forming a pattern of the stretchable composite by removing the patterned photosensitizer may further include the step of irradiating microwaves to the substrate on which the pattern of the stretchable composite is formed.

[0020] According to one embodiment, the step of removing the carbon thin film from the flexible wiring substrate may be performed through a plasma etching process.

[0021] According to one embodiment, the step of preparing a substrate on which a carbon thin film is formed, the step of forming a stretchable composite on the patterned photoresist, or the step of forming a stretchable substrate on the carbon thin film and the stretchable composite to form a stretchable wiring board including a pattern of the stretchable composite may be performed using at least one of spin coating, spray coating, ultrasonic spray coating, dip coating, and screen fritting.

[0022] According to one embodiment, the step of forming a pattern of the stretchable composite by removing the patterned photosensitizer may be such that the spacing of the stretchable composite pattern is 10 μm to 1000 μm.

[0023] According to one embodiment, in the step of preparing a substrate on which a carbon thin film is formed, the carbon thin film includes at least one selected from the group consisting of polyethylenimine (PEI), polyacrylic acid (PAA), and polyvinylpyrrolidone (PVP), is formed to a thickness of 5 nm to 50 nm, and may be formed at a temperature of 300°C to 350°C.

[0024] The present invention can provide a stretchable wiring board including a stretchable composite and a method for manufacturing the same.

[0025] A stretchable wiring board comprising a stretchable composite according to the present invention has high conductivity by using liquid metal particles, can be stretched by more than 100%, and can have high stretchability with a resistance change of 15% or less even at 50% stretch. Furthermore, by using a conventional photo process, it can have a high resolution of 10 μm and enables large-area patterning on a wafer scale.

[0026] FIG. 1 is a schematic diagram and an actual image of a stretchable wiring board before and after a carbon film is removed according to one embodiment of the present invention.

[0027] Figure 2 is a schematic diagram showing a method for manufacturing a flexible wiring board according to one embodiment of the present invention.

[0028] FIG. 3 is a schematic diagram and SEM image showing a method for forming a stretchable composite pattern on a carbon thin film formed on a substrate according to one embodiment of the present invention.

[0029] Figure 4 is a graph of the resistance change rate when a 10 μm-sized wire is stretched by 50% according to one embodiment of the present invention.

[0030] Hereinafter, embodiments are described in detail with reference to the attached drawings. However, the embodiments may be modified in various ways, and the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, or alternatives to the embodiments are included within the scope of the patent application.

[0031] The terms used in the examples are for illustrative purposes only and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but should be understood to not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0032] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments pertain. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0033] In addition, when describing with reference to the attached drawings, identical components will be assigned the same reference numerals regardless of the drawing numbers, and redundant descriptions thereof will be omitted. When describing embodiments, if a detailed description of a related known technology is judged to unnecessarily obscure the gist of the embodiment, the detailed description will be omitted.

[0034] Additionally, terms such as first, second, A, B, (a), (b), etc. may be used to describe components of the embodiments. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by the terms. When a component is described as being "connected," "coupled," or "connected" to another component, it should be understood that the component may be directly connected or connected to the other component, but another component may also be "connected," "coupled," or "connected" between each component.

[0035] Components included in one embodiment and components with common functions will be described using the same names in other embodiments. Unless otherwise stated, the descriptions given in one embodiment can be applied to other embodiments, and detailed descriptions will be omitted to the extent of overlap.

[0036] Hereinafter, the flexible wiring comprising liquid metal particles of the present invention and the method for manufacturing the same will be described in detail with reference to examples and drawings. However, the present invention is not limited to these examples and drawings.

[0037]

[0038] The stretchable composite of the present invention comprises: a stretchable substrate; and liquid metal particles formed within the stretchable substrate.

[0039] According to one embodiment, the stretchable composite of the present invention may be manufactured by using a stretchable substrate; and liquid metal particles formed within the stretchable substrate; as a conductive material to secure high elongation and high conductivity at the level of metals.

[0040] According to one embodiment, when a gallium indium alloy, which is a representative example of a liquid metal, is used as the liquid metal particle, there is no limitation on elongation because it is in a liquid state at room temperature, and it has a high conductivity at the level of a metal (3.4 x 10 6 Although it has a high surface tension (S / m), it may have the disadvantage of being difficult to pattern and easily coming off due to high surface tension. To solve this problem, the present invention may be a method of producing a stretchable composite ink by dispersing liquid metal in the form of particles in a solution in which a stretchable substrate is dissolved using an ultrasonic pulverizer, thereby producing a stretchable composite of the present invention.

[0041]

[0042] In one embodiment, among the extensible composites, the liquid metal particles may be 50 wt% to 95 wt%.

[0043] According to one embodiment, in the extensible composite, the liquid metal particles may be present in an amount of 50 wt% to 95 wt%; 60 wt% to 95 wt%; 65 wt% to 95 wt%; 70 wt% to 95 wt%; 75 wt% to 95 wt%; 80 wt% to 95 wt%; 85 wt% to 95 wt%; 50 wt% to 90 wt%; 50 wt% to 80 wt%; 50 wt% to 70 wt%; 50 wt% to 60 wt%.

[0044] According to one embodiment, in the above-described extensible composite, if the liquid metal particles are less than 50 wt%, there may be a problem in which a liquid metal particle film is not formed due to insufficient liquid metal particles, and if the liquid metal particles are more than 95 wt%, there may be a problem in which it is difficult to form a uniform liquid metal particle film due to a low polymer content.

[0045]

[0046] In one embodiment, the liquid metal particles may include at least one selected from the group consisting of a gallium-indium alloy, gallium, a gallium-indium-tin alloy, a gallium-indium-silver alloy, and a gallium-indium-copper alloy.

[0047] In one embodiment, the gallium (Ga) is a rare, soft, silvery post-transition metal with a melting point of 29.8° C., which allows it to exist as a liquid even at room temperature. In addition, the gallium-based liquid metal has high elasticity and low resistivity, and thus can be easily used in a stretchable composite. However, the gallium has an electronegativity of 1.8, which is similar to the electronegativity (1.6) of aluminum, another metal that is easily oxidized, and an ionization energy of 570 kJ / mol, making it a metal that is easily oxidized. When the gallium forms an alloy with a base metal that does not have oxidation resistance, the alloy can easily form an oxide film on the surface. If an insulating oxide film exists on the surface of the alloy, there may be a problem in that current cannot flow even when the liquid metal particles are in contact with each other.

[0048] In one embodiment, when an oxidation-resistant metal is added to the gallium to form an alloy, the alloy between the gallium and the oxidation-resistant metal also secures oxidation resistance due to the oxidation-resistant metal, so that the formation of a surface oxide film can be reduced or suppressed. The stretchable composite according to an embodiment of the present invention can ensure reliability and economy without decreasing conductivity.

[0049]

[0050] The stretchable wiring board of the present invention comprises: a stretchable substrate; and a wiring comprising the stretchable composite of claim 1 formed on the stretchable substrate.

[0051] FIG. 1 is a schematic diagram and an actual image of a stretchable wiring board before and after a carbon film is removed according to one embodiment of the present invention.

[0052] Referring to FIG. 1, the stretchable wiring board (100) before the carbon film is removed includes a carbon film (110), a stretchable composite (120), and a stretchable substrate (130).

[0053] According to one embodiment, when removing the carbon thin film (110), it may be performed through an oxygen plasma etching process.

[0054] Also, referring to FIG. 1, the stretchable wiring board (150) after the carbon film is removed includes a stretchable composite (120) and a stretchable substrate (130). The stretchable wiring board (150) includes a stretchable substrate (130); and wiring including a stretchable composite (120) formed on the stretchable substrate (130).

[0055]

[0056] In one embodiment, the stretchable substrate may include at least one selected from the group consisting of polydimethylsiloxane (PDMS), Ecoflex, dragon skin, and poly(styrene-co-butadiene) (SEBS).

[0057] According to one embodiment, the stretchable substrate may be provided as a stretchable and flexible substrate, may be provided in a thin plate shape, and may preferably be a PDMS (Polydimethylsiloxane) substrate. The PDMS is a stretchable polymer material, has homogeneous isotropic properties, is optically transparent up to a thickness of 300 nm, and has strong durability, so that its physical properties do not degrade even after long-term use.

[0058] In one embodiment, the stretchable substrate may be formed of an insulating material that can be bent or stretched as a flexible substrate. For example, the stretchable substrate may be formed of an elastic polymer such as silicone rubber (polydimethylsiloxane; PDMS), polyurethane (PU), or the like, and thus may have flexible properties. However, the material of the stretchable substrate is not limited thereto.

[0059] In one embodiment, the extensible substrate is a flexible substrate capable of reversible expansion and contraction. In addition, the elastic modulus may be several MPa to several hundred MPa, and the elongation fracture rate may be 100% or higher. The thickness of the lower substrate may be, but is not limited to, 10 μm to 1 mm.

[0060]

[0061] In one embodiment, the thickness of the wiring: diameter of the liquid metal particles may be 1:0.01 to 1:1.

[0062] In one embodiment, the thickness of the wiring: the diameter of the liquid metal particles is 1:0.01 to 1:1; 1:0.05 to 1:1; 1:0.1 to 1:1; 1:0.2 to 1:1; 1:0.3 to 1:1; 1:0.5 to 1:1; 1:0.6 to 1:1; 1:0.7 to 1:1; 1:0.8 to 1:1; 1:0.9 to 1:1; 1:0.01 to 1:0.9; 1:0.01 to 1:0.7; 1:0.01 to 1:0.5; 1:0.01 to 1:0.3; 1:0.01 to 1:0.1; It can be 1:0.01 to 1:0.05;

[0063] According to one embodiment, if the thickness of the wiring: the diameter of the liquid metal particles is outside the above range, there may be a problem that the patterning resolution and thickness of the photosensitive agent used for patterning in the step of forming and patterning a photosensitive agent on the carbon thin film in the method for manufacturing a stretchable wiring board of the present invention are not appropriate.

[0064]

[0065] In one embodiment, the wiring has a conductivity of 10 5 S / m to 10 6 It is S / m and can have an elongation of 50% to 200%.

[0066] In one embodiment, the wiring has a conductivity of 10 5 S / m to 10 6 S / m; 2*10 5 S / m to 10 6 S / m; 3*10 5 S / m to 10 6 S / m; 4*10 5 S / m to 10 6 S / m; 5*10 5 S / m to 10 6 S / m; 6*10 5 S / m to 10 6 S / m; 7*10 5 S / m to 10 6 S / m; 8*10 5 S / m to 10 6 S / m; 9*10 5 S / m to 10 6 S / m; 10 5 S / m to 0.9*10 6 S / m; 10 5 S / m to 0.7*10 6 S / m; 10 5 S / m to 0.5*10 6 S / m; 10 5 S / m to 0.3*10 6 S / m; 10 5 S / m to 0.2*10 6It could be S / m;

[0067] In one embodiment, the wiring may have an elongation of 50% to 200%; 50% to 180%; 50% to 150%; 50% to 120%; 50% to 100%; 50% to 80%; 70% to 200%; 90% to 200%; 100% to 200%; 120% to 200%; 150% to 200%; 170% to 200%.

[0068] In one embodiment, the wiring has a conductivity of 10 5 If it is less than S / m, the conductivity may not be sufficiently secured, so that current may not flow, or there may be a problem in utilizing it in a photo process. If the stretchability is less than 50%, there may be a problem in that it may be difficult to achieve high integration of the wiring. In addition, if the conductivity and stretchability of the wiring are outside the above range, there may be a problem in that it may not be possible to produce a high-resolution, high-stretch, and high-conductivity wiring by patterning the wiring through a photo process.

[0069]

[0070] According to one embodiment, the wiring may have a resistance change rate of 15% or less when elongated by 50%.

[0071] FIG. 4 is a graph of the resistance change rate when a 10 μm-sized wire is stretched by 50% according to one embodiment of the present invention.

[0072] Referring to Fig. 4, it can be confirmed that the resistance change rate of the above wiring is 15% or less when extended by 50%.

[0073] In one embodiment, the wiring may include the stretchable composite of claim 1 formed on the stretchable substrate, wherein the stretchable composite may include: a stretchable substrate; and liquid metal particles formed within the stretchable substrate.

[0074] According to one embodiment, the wiring may include the liquid metal particles, and the method for manufacturing a flexible wiring substrate of the present invention may include a step of irradiating microwaves, thereby generating conductivity between the liquid metal particles.

[0075] In one embodiment, conductivity is imparted between the liquid metal particles, so that the wiring can be a highly conductive and highly ductile wiring.

[0076] According to one embodiment, the wiring can have a high resolution of 10 μm using a photo process, and can enable large-area patterning of wafer size.

[0077]

[0078] The method for manufacturing a stretchable wiring board of the present invention comprises the steps of: preparing a substrate having a carbon thin film formed thereon; forming a photosensitive agent on the carbon thin film and patterning it; forming a stretchable composite on the patterned photosensitive agent; removing the patterned photosensitive agent to form a pattern of the stretchable composite; forming a stretchable substrate on the carbon thin film and the stretchable composite to form a stretchable wiring board including a pattern of the stretchable composite; and separating the stretchable wiring board from the substrate and removing the carbon thin film from the stretchable wiring board.

[0079] Figure 2 is a schematic diagram showing a method for manufacturing a flexible wiring board according to one embodiment of the present invention.

[0080] Referring to FIG. 2, the first step is to prepare a substrate (230) on which a carbon thin film (220) is formed, and to spin-coat a photosensitive agent (210) onto the carbon thin film (220).

[0081] The second step of FIG. 2 illustrates a step of patterning the photosensitive agent (210). According to one embodiment, the photosensitive agent (210) may be, but is not limited to, AZ 2070 or AZ 4330.

[0082] The third step of Fig. 2 shows a step of forming a stretchable complex (240) by spin coating on the patterned photosensitive agent (210).

[0083] The fourth step of Fig. 2 shows a step of forming a pattern of the stretchable composite (240) by removing the patterned photosensitive agent (210).

[0084] After the fourth step of Fig. 2, the patterned stretchable composite (240) may be irradiated with microwaves to impart conductivity.

[0085] The fifth step of FIG. 2 illustrates a step of forming a stretchable wiring substrate including a pattern of the stretchable composite (240) by spin-coating a stretchable substrate (250) on the carbon thin film (220) and the patterned stretchable composite (240).

[0086] The sixth step of Fig. 2 illustrates a step of separating the flexible wiring substrate by immersing the substrate (230) in water. This may involve immersing the carbon thin film (220) having weak adhesion to the substrate (230) in water to separate it from the substrate (230). This may involve transferring a target from one substrate to another using the carbon thin film (220).

[0087] According to one embodiment, a method of putting the carbon thin film (220) having weak adhesion to the substrate (230) into water and separating it from the substrate (230) may be a method that can be used when transferring a target heat-treated at 300°C or less from a substrate to another substrate.

[0088] The seventh step of FIG. 2 shows that the stretchable wiring substrate (200) separated from the substrate (230) includes the carbon thin film (220), the patterned stretchable composite (240), and the stretchable substrate (250).

[0089] The eighth step of FIG. 2 illustrates that the stretchable wiring substrate (260) after the carbon film is removed includes the patterned stretchable composite (240) and the stretchable substrate (250). The stretchable wiring substrate (260) may include a stretchable substrate (250); and wiring including the stretchable composite (240) formed on the stretchable substrate (250).

[0090] According to one embodiment, when removing the carbon thin film (220), it may be performed through an oxygen plasma etching process.

[0091]

[0092] According to one embodiment, the step of forming a pattern of the stretchable composite by removing the patterned photosensitizer may further include the step of irradiating microwaves to the substrate on which the pattern of the stretchable composite is formed.

[0093] According to one embodiment, the method further comprises the step of irradiating a substrate on which a pattern of the stretchable composite is formed with microwaves; so that the substrate on which the pattern of the stretchable composite is formed absorbs the microwaves, thereby increasing its temperature, and through the heat, conductivity may occur between liquid metal particles formed in the stretchable substrate included in the stretchable composite.

[0094] According to one embodiment, the substrate on which the pattern of the stretchable composite is formed is a substrate capable of absorbing microwaves, and the cause of the conductivity between the liquid metal particles may be primarily microwave absorption of the substrate on which the pattern of the stretchable composite is formed, rather than microwave absorption of the liquid metal particles.

[0095]

[0096] According to one embodiment, the step of removing the carbon thin film from the flexible wiring substrate may be performed through a plasma etching process.

[0097] According to one embodiment, the step of removing the carbon thin film from the stretchable wiring board may be performed through a plasma etching process using O2 gas. For example, when removing the carbon thin film from the stretchable wiring board, the O2 plasma etching process may be performed by flowing 50 sccm to 100 sccm of O2 gas and applying 200 W to 250 W for 1 minute to 3 minutes.

[0098]

[0099] According to one embodiment, the step of preparing a substrate on which a carbon thin film is formed, the step of forming a stretchable composite on the patterned photoresist, or the step of forming a stretchable substrate on the carbon thin film and the stretchable composite to form a stretchable wiring board including a pattern of the stretchable composite may be performed using at least one of spin coating, spray coating, ultrasonic spray coating, dip coating, and screen fritting.

[0100] FIG. 3 is a schematic diagram and SEM image showing a method for forming a pattern of a stretchable composite on a carbon thin film formed on a substrate according to one embodiment of the present invention.

[0101] The first step of Fig. 3 illustrates a step of patterning a carbon thin film (220) formed on a substrate (230) and a photoresist (210) formed on the carbon thin film (220). According to one embodiment, the photoresist (210) may be AZ 2070 or AZ 4330, but is not limited thereto. Referring to the SEM image of the first step of Fig. 3, the patterned photoresist (210) can be confirmed.

[0102] The second step of Fig. 3 illustrates a step of forming a stretchable composite (240) by spin coating on the patterned photoresist (210). Referring to the SEM image of the second step of Fig. 3, it can be confirmed that the pattern of the photoresist (210) becomes blurred when the stretchable composite (240) is spin coated on the patterned photoresist (210).

[0103] The third step of Fig. 3 illustrates a step of forming a pattern of the stretchable composite (240) by removing the patterned photosensitive agent (210). Referring to the SEM image of the third step of Fig. 3, the patterned stretchable composite (240) can be confirmed.

[0104]

[0105] According to one embodiment, the step of forming a pattern of the stretchable composite by removing the patterned photosensitizer may be such that the spacing of the stretchable composite pattern is 10 μm to 1000 μm.

[0106] In one embodiment, the step of forming a pattern of the stretchable composite by removing the patterned photosensitive agent; wherein the spacing of the stretchable composite pattern is 10 ㎛ to 1000 ㎛; 10 ㎛ to 900 ㎛; 10 ㎛ to 800 ㎛; 10 ㎛ to 700 ㎛; 10 ㎛ to 500 ㎛; 10 ㎛ to 400 ㎛; 10 ㎛ to 300 ㎛; 10 ㎛ to 200 ㎛; 10 ㎛ to 100 ㎛; 50 ㎛ to 1000 ㎛; 100 ㎛ to 1000 ㎛; 200 ㎛ to 1000 ㎛; 300 ㎛ to 1000 ㎛; 500 ㎛ to 1000 ㎛; 700 ㎛ to 1000 ㎛; It may be 900 ㎛ to 1000 ㎛.

[0107] According to one embodiment, the step of forming a pattern of the stretchable composite by removing the patterned photosensitive agent may have a problem in that the patterned photosensitive agent is not removed when the spacing of the stretchable composite pattern is less than 10 μm.

[0108] The above pattern may comprise at least one selected from the group consisting of straight lines, curved lines, mesh lines, reticulated lines, polygonal lines, circular lines, oval lines, arc lines, fan lines and combinations thereof, and preferably comprises a straight line.

[0109]

[0110] According to one embodiment, in the step of preparing a substrate on which a carbon thin film is formed, the carbon thin film includes at least one selected from the group consisting of polyethylenimine (PEI), polyacrylic acid (PAA), and polyvinylpyrrolidone (PVP), is formed to a thickness of 5 nm to 50 nm, and may be formed at a temperature of 300°C to 350°C.

[0111] According to one embodiment, in the step of preparing a substrate on which a carbon thin film is formed, the step of spin-coating at least one selected from the group consisting of polyethylenimine (PEI), polyacrylic acid (PAA), and polyvinylpyrrolidone (PVP) on the substrate to form a thin film, and then irradiating the substrate with microwaves may be further included to form a carbon thin film.

[0112] According to one embodiment, most polymers are difficult to use for transferring films on substrates heat-treated by microwave irradiation because they are carbonized and thermally decomposed at temperatures above 300°C, but the carbon thin film according to one embodiment of the present invention is formed at a temperature of 300°C to 350°C and is stable at temperatures below 300°C, so it can be used on substrates heat-treated by microwave irradiation.

[0113]

[0114] Hereinafter, the present invention will be described in more detail by way of examples.

[0115] However, the following examples are only intended to illustrate the present invention, and the content of the present invention is not limited to the following examples.

[0116]

[0117] Example

[0118] After SEBS-g-ma was dissolved in toluene as a stretchable material, 20 wt% of liquid metal (EGaln) was added and ultrasonic treatment (20 min) was performed to prepare a stretchable composite containing liquid metal particles.

[0119] To transfer the target from one substrate to another, a thin film of polyacrylic acid (PAA) was spin-coated (3000 rpm, 30 sec) on a silicon substrate, and the polymer thin film was converted into a carbon thin film through microwave irradiation at 300°C for 1 min to form a sacrificial layer. A photoresist (AZ 2070 or AZ 4330) was patterned on the silicon substrate with the carbon thin film. A stretchable composite containing liquid metal particles in ink form was spin-coated (2000 rpm, 30 sec) on the patterned photoresist. The substrate coated with the stretchable composite was immersed in acetone to remove the remaining photoresist, thereby patterning the stretchable composite.

[0120]

[0121] Conductivity was imparted to the patterned stretchable composite by microwave irradiation at 340°C for 1 min. The stretchable composite containing conductive liquid metal particles was spin-coated (500 rpm, 30 s) onto the patterned substrate using PDMS as a stretchable substrate, higher than the height of the stretchable composite pattern, to produce a stretchable wiring substrate containing the stretchable composite pattern. Thereafter, the stretchable wiring substrate was detached from the silicon substrate by immersing the silicon substrate in water, and the carbon film was removed through 02 plasma treatment (200 W, 3 min).

[0122]

[0123] Although the embodiments described above have been described with limited drawings, those skilled in the art will appreciate that various technical modifications and variations can be applied based on the above. For example, appropriate results can still be achieved even if the described techniques are performed in a different order than described, and / or components of the described systems, structures, devices, circuits, etc. are combined or combined in a different manner than described, or are replaced or substituted with other components or equivalents.

[0124] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims described below.

Claims

1. Extensible substrate; and Comprising liquid metal particles formed within the above extensible substrate; Stretchable complex.

2. In paragraph 1, Among the above extensible composites, the liquid metal particles are 50 wt% to 95 wt%, Stretchable complex.

3. In paragraph 1, The liquid metal particles include at least one selected from the group consisting of a gallium-indium alloy, gallium, a gallium-indium-tin alloy, a gallium-indium-silver alloy, and a gallium-indium-copper alloy. Stretchable complex.

4. Flexible substrate; and A wiring comprising the stretchable composite of claim 1 formed on the stretchable substrate; including, Flexible wiring board.

5. In paragraph 4, The above extensible substrate comprises at least one selected from the group consisting of PDMS (polydimethylsiloxane), Ecoflex, dragon skin, and SEBS (poly(styrene-co-butadiene). Flexible wiring board.

6. In paragraph 4, The thickness of the above wiring: the diameter of the above liquid metal particles is 1:0.01 to 1:1, Flexible wiring board.

7. In paragraph 4, The above wiring has a conductivity of 10 5 S / m to 10 6 It is S / m, The elongation is 50% to 200%, Flexible wiring board.

8. In paragraph 4, The above wiring, when extended by 50%, The resistance change rate is less than 15%, Flexible wiring board.

9. Step of preparing a substrate on which a carbon film is formed; A step of forming a photosensitive agent on the carbon thin film and patterning it; A step of forming a stretchable complex on the patterned photosensitive agent; A step of forming a pattern of the stretchable composite by removing the patterned photosensitive agent; A step of forming a stretchable substrate on the carbon thin film and the stretchable composite, thereby forming a stretchable wiring substrate including a pattern of the stretchable composite; and A step of separating the flexible wiring substrate from the substrate and removing the carbon thin film from the flexible wiring substrate; Method for manufacturing a flexible wiring board.

10. In paragraph 9, A step of forming a pattern of the stretchable composite by removing the patterned photosensitive agent; It further includes a step of irradiating microwaves to a substrate on which a pattern of the above-mentioned extensible complex is formed; Method for manufacturing a flexible wiring board.

11. In paragraph 9, The step of removing the carbon thin film from the above flexible wiring board; It is performed through a plasma etching process, Method for manufacturing a flexible wiring board.

12. In paragraph 9, A step of preparing a substrate on which a carbon film is formed, a step of forming a stretchable composite on the patterned photosensitive agent, or a step of forming a stretchable substrate on the carbon film and the stretchable composite to form a stretchable wiring substrate including a pattern of the stretchable composite, It is performed using at least one of spin coating, spray coating, ultrasonic spray coating, dip coating and screen fritting. Method for manufacturing a flexible wiring board.

13. In paragraph 9, A step of forming a pattern of the stretchable composite by removing the patterned photosensitive agent; The spacing of the above-mentioned elastic composite pattern is 10 ㎛ to 1000 ㎛, Method for manufacturing a flexible wiring board.

14. In paragraph 9, In the step of preparing a substrate on which a carbon film is formed; The above carbon film comprises at least one selected from the group consisting of polyethylenimine (PEI), polyacrylic acid (PAA), and polyvinylpyrrolidone (PVP). It is formed with a thickness of 5 nm to 50 nm, It is formed at a temperature of 300 ℃ to 350 ℃, Method for manufacturing a flexible wiring board.

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