KR101435255B1 - Circuit Board Prepared by Nanoparticle Alignment, Guided through Interfacial Interaction and Microfabricated Structure on Substrate, the pattern printing method thereof and the manufacturing method for mold therefor - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a printed circuit board, a printed circuit board according to the method, and a method of manufacturing a mold for manufacturing a printed circuit board, The method includes a first step of forming a thin film on a substrate with a synthetic resin solution; A second step of forming a concave-convex pattern on the thin film; A third step of injecting a nanoparticle solution onto the surface of the thin film to arrange the nanoparticles along the pattern of the concavo-convex shape; And a fourth step of sintering the surface of the thin film to form a circuit pattern in which nanoparticles are arranged.
According to the present invention, cost competitiveness can be ensured compared with the conventional exposure process, eco-friendliness of the process can be achieved, and since the printing process is performed at a low temperature and a normal pressure, it can be utilized for a plastic substrate. There are no restrictions. That is, through the development of a nanoparticle array printing process, it is possible to obtain an additional advantage of being able to manufacture a flexible display (often a flexible display).

Description

Technical Field The present invention relates to a circuit board manufactured by nanoparticle array induced by microstructure and interfacial interaction, a method of printing the pattern, and a method of manufacturing a mold using the nanoparticle array. and the manufacturing method for mold therefor}

The present invention relates to a method for manufacturing a printed circuit board, a printed circuit board according to the method, and a method for manufacturing a mold for a method for manufacturing a printed circuit board.

Photolithography is the most popular technique for patterning with polymers. The exposure process refers to a method of transferring a pattern on a mask to a substrate using a photoresist that reacts to a specific wavelength such as ultraviolet light.

A semiconductor circuit is usually a multilayer film composed of several layers, and a circuit can be connected or isolated from an adjacent circuit only when a pattern is formed at a desired position. Therefore, it is essential to align the mask to the desired position when placing the mask on the substrate. The mask has markers for alignment at the corners, and usually the laser is applied to the markers to determine the optimal position by determining the amount of light reflected from the bottom. Exposure is the most critical step, and the light is irradiated for a reasonable time to the desired intensity and transferred to the photoresist on the substrate.

The development is a process of removing the photoresist layer in a portion to be etched, and forms a selective photoresist pattern using a solvent suitable for the given photoresist. Developing methods include spraying or Immersion method, which immerses the developing solution and cleaning solution in order, but the latter method is often used for stable development.

After the development, heat treatment is performed again to enhance the adhesion between the photoresist and the substrate. At this time, the excess solvent existing in the photoresist film is removed, and the adhesion is greatly increased. The process conditions are slightly harsher than those of soft bake, and are between 10 and 20 minutes at 100 ~ 150 ℃. Excessive heat treatment can also result in scum formation, making photoresist removal difficult.

When the step of the exposure process is completed, the pattern of the photoresist is transferred to the substrate by mainly dry etching as a subsequent process. Currently, there are various technological and economic difficulties in implementing the pattern of 100 nm or less in the exposure process, and technologies using short wavelength such as Deep UV, X-ray, and E-Beam will be developed in succession as next-generation exposure technologies. On the other hand, non-conventional patterning methods using polymeric materials other than photoresists have been developed to solve these problems.

On the other hand, high temperature vacuum deposition, photolithography (photolithography), and wet and dry etching have been widely used for the manufacture of screen display devices. In the situation where the substrate on which the circuit is fabricated is becoming increasingly large, the above-mentioned methods consume a lot of energy and materials, and toxic solvents must be used and thus generate a large amount of waste liquid which is harmful to the environment. To solve these problems, a nano particle array printing process has been proposed.

In some processes for manufacturing a screen display device, a limited number of nanoparticle array processes have been attempted. However, since the nanoparticle array printing process developed so far has various problems, it can not be generalized. It was found that the wiring of the manufactured circuit had a low adhesion force with the substrate, a change in conductivity, and insufficient control of the drop point of the ink. These problems must be overcome in order for the nanoparticle array printing process to be widely applied to the display process. Efforts are being made to solve these problems, but no clear solution has yet been found. The solutions proposed so far are focused on the development of powder, paste, and nanoparticles used in ink development-circuit manufacturing.

The present invention provides a low cost, environmentally friendly pattern forming method and a printed circuit board therefor in place of the existing exposure process.

In addition, the present invention provides a pattern forming method capable of being manufactured at room temperature without limitation on a substrate and a pattern material, and a printed circuit board therefor.

A method of pattern printing using a nanoparticle array according to the present invention includes: a first step of forming a thin film on a substrate with a solution of a synthetic resin; A second step of forming a concave-convex pattern on the thin film; A third step of modifying the surface of the thin film to be hydrophobic; A fourth step of injecting a nanoparticle solution onto the surface of the thin film to arrange the nanoparticles along the concavo-convex pattern; And a fifth step of sintering the surface of the thin film to form a circuit pattern in which nanoparticles are arranged.

In the second step, the concavo-convex pattern may be formed by soft lithography.

In the second step, the synthetic resin thin film is pressed by means of a mold having a concavo-convex pattern inversely formed. And (2-2) curing the synthetic resin thin film in the pressed state.

In the step 2-2, heating and cooling may be sequentially applied to cure.

In the third step, the surface of the thin film is treated with octadecyl trimethoxysilane, octadecyl trichlorosilane (

Octadecyltrichlorosilane, octadecyltriethoxysilane, octadecyldimethylmethoxysilane, and octadecyldimethylchlorosilane. The reaction may be carried out in the presence of a catalyst.

Also, the surface of the thin film may be oxidized before the reaction with octadecyl trimethoxysilane (Sigma) in the surface modification step. At this time, the thin film may be oxidized to a mixed solution of potassium permanganate (KMnO4) and sulfuric acid.

The method may further include repeating the fourth and fifth steps.

The fourth step may be performed by a micro-syringe (SYR-11, Narashige).

Meanwhile, a printed circuit board having a pattern formed by the nanoparticle array according to the present invention includes a substrate; A thin film provided on the substrate and having a concavo-convex pattern; And a nanoparticle pattern arranged and sintered along the concavo-convex pattern by interfacial action.

The thin film may be formed of a polystyrene material.

Further, the pattern of the thin film may be formed at an obtuse angle.

The substrate may be formed of a material including at least one of polycarbonate, polyester, polyethylenenaphthalate, polyetherimide, polyvinylalcohol, polyethylene terephthalate, polyethersulfone, polyetheretherketone, polyimide, and glass.

The present invention also provides a method of manufacturing a mold for forming a pattern by a nanoparticle array according to the present invention, comprising the steps of: forming a pattern shape so as to be concave and convex on a silicon wafer; A second step of pouring a mixed solution of a monomer of a polymer compound and a curing agent onto the silicon wafer; A third step of solidifying the mixed solution; And a fourth step of separating the cured polymer compound from the silicon wafer.

Also, the pattern shape of the first step may be formed at an obtuse angle.

The pattern shape of the first step may be formed by electron beam lithography.

The polymer compound may also be polydimethylsiloxane (Sylgard 184, Dow Corning).

Also, the third step may be performed in a vacuum state.

According to the present invention, a combination of interface interaction with nanoparticles based on substrate surface modification and soft lithography (soft lithography) can be applied to improve control of the arrangement of nanoparticles in the substrate.

Further, according to the present invention, cost competitiveness can be ensured compared with the conventional exposure process, and the process can be eco-friendly.

Further, according to the present invention, since the printing process is performed at room temperature and atmospheric pressure, it can be used for a plastic substrate, and there is no restriction on the material used for manufacturing the microstructure. That is, through the development of a nanoparticle array printing process, it is possible to obtain an additional advantage of being able to manufacture a flexible display (often a flexible display).

FIG. 1 is a flowchart illustrating a method of removing molds for a printed circuit board having a pattern formed by a nanoparticle array according to an embodiment of the present invention. Referring to FIG.
FIG. 2 is a flowchart showing a printed circuit board having a pattern formed by a nanoparticle array according to an embodiment of the present invention, a method of printing the pattern, and a method of manufacturing a mold.
3 is a photograph showing the nanoparticle array state according to one embodiment.
4 is a photograph showing an operation of a printed circuit board on which a pattern is formed by the nanoparticle array according to one embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the absence of special definitions or references, the terms used in this description are based on the conditions indicated in the drawings.

Referring to FIG. 1, a method of manufacturing a mold for pattern formation by nanoparticle array according to an embodiment of the present invention will be described. 1 is a flowchart illustrating a method of manufacturing a mold for a printed circuit board on which a pattern is formed by the nanoparticle array according to an embodiment of the present invention.

In order to manufacture a mold for forming a concavo-convex pattern on a substrate, a pattern is formed so as to be concave and convex on a silicon wafer (S10). At this time, it is preferable that the irregularities formed on the silicon wafer are formed to be engraved. The silicon wafer is a constituent part serving as a mold for producing a mold, and finally has the same shape as the concavo-convex shape formed on the substrate. That is, a pattern is formed on the silicon wafer at an engraved pattern in order to form an engraved pattern on the substrate. In this embodiment, a line having a width of 3 mu m and a depth of 1 mu m is formed on the silicon wafer by an electron beam lithography technique at a negative angle.

Next, a mixed solution of the monomer of the polymer compound and the curing agent is poured onto the silicon wafer (S20). Polydimethylsiloxane (Sylgard 184, Dow Corning) may be used as the polymer compound. In this embodiment, a solution of a polydimethylsiloxane (Sylgard 184, Dow Corning) monomer and a curing agent in a ratio of 10: 1 was placed on a silicon wafer having a pattern formed thereon.

Next, a mixed solution of the polymer compound monomer and the curing agent is cured (S30). In this Example, a solution of a polydimethylsiloxane (Sylgard 184, Dow Corning) monomer mixed with a curing agent in a ratio of 10: 1, which was put on a silicon wafer under vacuum at 60 ° C for 4 hours, was allowed to stand until it solidified.

Next, the cured polymer compound is separated from the silicon wafer to complete the production of the mold using the polymer compound (S40).

2 to 3, a method of fabricating a patterned printed circuit board according to an embodiment of a nanoparticle array and a printed circuit board therefor will be described. FIG. 2 is a flow chart showing a method of printing a pattern by a nanoparticle array according to an embodiment of the present invention, FIG. 3 is a photograph showing a nanoparticle array state according to an embodiment, FIG. FIG. 2 is a photograph showing an operation of a printed circuit board on which a pattern is formed by the arrangement of nanoparticles according to the present invention.

In order to print a pattern on a substrate using the nanoparticle array according to the present invention, a thin film is first formed on a substrate with a synthetic resin solution (S110). At this time, the printing method according to the present invention proceeds at a relatively room temperature compared with the conventional exposure process, and minimizes the chemical reaction, so that the selection of the material of the substrate varies greatly. In the present embodiment, polycarbonate (Tg = 155 ° C, Zen Corporation) which is a general-purpose plastic is selected as a substrate. To form a thin film, a mixed solution prepared by dissolving polystyrene (Mw = 2.3x105, Tg = 100 ° C, Aldrich) in toluene at 10% (w / v) was put on a polycarbonate substrate to form a thin film. At this time, various methods can be used to form a thin film. In this embodiment, a thin film forming method using rotation (spin coating) was used. Meanwhile, the substrate may be formed of a polymer and glass that can form a transparent substrate such as polyester, polyethylenenaphthalate, polyetherimide, polyvinylalcohol, polyethylene terephthalate, polyethersulfone, polyetheretherketone, and polyimide in addition to polycarbonate.

Next, a concave-convex pattern is formed on the thin film formed on the substrate. In order to form a concave-convex pattern on the thin film, the thin film is pressed using the template (S120). That is, in this step, a concave-convex pattern is formed by soft lithography using a mold. At this time, the thin film is formed opposite to the unevenness of the mold. That is, as described above, when the silicon wafer is formed at a negative angle, the mold is patterned with a positive angle, and the thin film formed on the substrate again has a negative angle pattern. Subsequently, the thin film on the substrate is cured under pressure (S130). The curing of the thin film can be performed by various methods, but in this embodiment, the thin film in a pressurized state is gradually heated to 150 캜 and maintained for 1 hour, and then slowly cooled to room temperature. As a result, the pattern of the engraved pattern was formed on the polystyrene thin film by the microstructure pattern of the mold.

Next, the surface of the thin film on which the concave-convex pattern is formed is modified to be hydrophobic (S140). At this time, the surface of the thin film can be reacted with octadecyl trimethoxysilane (Sigma) after the surface of the thin film is oxidized. On the other hand, octadecyltrimethoxysilane can be produced by a silane reaction such as octadecyltrichlorosilane, octadecyltriethoxysilane, octadecyldimethylmethoxysilane, octadecyldimethylchlorosilane, etc. Can be reacted with a substance that can become hydrophobic.

In this embodiment, in order to modify the surface of the microstructure of the polystyrene thin film to be hydrophobic, it is first oxidized with a mixture of 4: 1 (w / w) potassium permanganate (KMnO4) and sulfuric acid for 1 minute. The oxidized surface is treated with a solution of octadecyl trimethoxysilane (Sigma) in a nitrogen atmosphere for 2 hours. The octadecyltrimethoxysilane solution used was 0.5% (v / v) concentration and anhydrous toluene was used as the solvent. Treatment of this silane material results in long alkyl functional groups chemically bonded to the substrate surface. The results of the silane treatment can be found from the measurement of the contact angle.

Next, the nanoparticle solution is sprayed on the surface of the thin film (S150) to arrange the nanoparticles along the concavo-convex pattern. At this time, the injection of the nanoparticles can be performed by a micro-syringe (SYR-11, Narashige).

In this embodiment, 20 nm silver nanoparticles (concentration 30-35%, DGP 40LT-15C, Nano New Material Co., Ltd.) are injected onto the surface of the microstructure. The solvent of the nanoparticles is triethyleneglycol - monoethylether with an interfacial tension of 35 ~ 38 mN / m and a viscosity of about 10 cP, which is much higher than water. Immediately before spraying, mix in 10 times water.

Finally, the surface of the thin film is sintered to form a circuit pattern in which nanoparticles are arranged (S160). In this example, after spraying, the solvent was evaporated in the air for 1 hour and maintained at 150 占 폚 for 30 minutes. The process of spraying, evaporation and sintering is repeated three times on the surface of the same area so that it can be applied as wiring without disconnection.

The results of observing the arrangement of the nanoparticles with an optical microscope of the nanoparticles are shown in FIG. FIG. 3 (a) shows a pattern of intaglio formed on a thin film, and FIG. 3 (b) shows nanoparticles arranged along a pattern of a negative pattern of a thin film. That is, as shown in FIG. 3 (b), the sintered nanoparticles were arranged along the pattern of the depressions formed on the thin film, and the density was dense.

In order to perform the function as a pattern, the spraying of the nanoparticle solution, evaporation and sintering can be repeated several times. As the repetition of the spraying, evaporation and sintering of the nanoparticle solution was repeated several times, the density of the nanoparticles arranged along the pattern was increased.

As described above, the polydimethylsiloxane template has an embossed shape as silicon wafers are produced intaglio. Thus, the microstructure on the polycarbonate substrate is engraved. The nanoparticle solution was sprayed by a microsyringe (SYR-11, Narashige) along a line-like structure in units of 100-200 μL drop. Immediately after being sprayed, the solutions were spread to the outside of the engraved pattern. From the results of FIG. 3 (b) obtained after the completion of injection, evaporation and calcination, it was found that the nanoparticles were gathered in the intaglio region. During the evaporation process, the solvent of the nanoparticle solution in the intaglio region was evaporated at the end, and the hydrophilic particles were gathered in the indentation region. As shown in Fig. 3 (b), no nanoparticles are observed outside the engraved area.

It is more preferable that the nanoparticle solution contains materials for dispersion stability or that the functional groups for dispersion stability exist on the surface in the course of manufacturing nanoparticles. Functional groups for dispersion stability exist on the particle surface, which acts as a resistance in the future when the wiring is utilized. Therefore, sintering is performed to remove the substances contributing to the dispersion stability of the nanoparticles and to increase the contact between the metal nanoparticles. Also, the affinity between the metal nanoparticles and the substrate is increased through sintering. This is because the removal of functional groups causes the surface of the metal nanoparticles with a large Hamaker constant to come into direct contact with the substrate surface. The sintering temperature was determined to be 150 ° C, since it is determined to induce the movement of the metal atoms but does not cause evaporation of atoms and does not cause deformation of the substrate. After sintering, it was verified that the plastic substrate functions as a wiring. A voltage of 5 V was supplied from a power supply (PWS-3003D, Provice), and a plastic substrate on which silver nanoparticles were arrayed was installed in the middle of the wiring by this experimental procedure. And I confirmed that the LED (one technology) bulb is lit. The results are shown in Fig. As shown in FIG. 4 (B), a pattern was formed on the synthetic resin substrate using the above-described method and connected between the voltage source and the electrical path of the LED. As a result, it was confirmed that the LED was lit as shown in FIG. 4 (A), and it was confirmed that the printed circuit board having the pattern formed according to the present invention functions normally.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, A pattern printing method, and a mold manufacturing method.

Claims (18)

A first step of forming a thin film on a plastic substrate with a synthetic resin solution, the synthetic resin having a lower glass transition temperature (Tg) than the substrate;
A second step of forming a concavo-convex pattern on the thin film while heating at a temperature higher than the glass transition temperature of the synthetic resin and lower than the glass transition temperature of the substrate for a preset time and then cooling;
A third step of modifying the surface of the thin film to be hydrophobic;
A fourth step of spraying the nanoparticle solution onto the surface of the thin film; And
And sintering the surface of the thin film at a temperature lower than a glass transition temperature of the substrate to form a circuit pattern in which the nanoparticles are arranged along the concavo-convex pattern,
Wherein the substrate has a glass transition temperature of 155 DEG C or less. The method according to claim 1,
Wherein the pattern of the concavo-convex pattern is formed by soft lithography in the second step. 3. The method of claim 2,
The second step comprises:
A second step of pressing the thin film by means of a mold having a concavo-convex pattern inversely formed; And
And (2-2) curing the thin film in the pressed state. The method of claim 3,
The method of pattern printing using nanoparticle array in which the heating and cooling are successively applied in the step 2-2. The method according to claim 1,
In the third step, the surface of the thin film is treated with octadecyl trimethoxysilane, octadecyl trichlorosilane (
Wherein the reaction is carried out with at least one of octadecyltrichlorosilane, octadecyltriethoxysilane, octadecyldimethylmethoxysilane, and octadecyldimethylchlorosilane. 6. The method of claim 5,
In the third step, the surface of the thin film is oxidized before the reaction with N-octadecyl trimethoxysilane. The method according to claim 6,
Wherein said thin film is patterned using a nanoparticle array that is oxidized with a potassium permanganate (KMnO4) and sulfuric acid mixed solution. The method according to claim 1,
And repeating the fourth step and the fifth step. The method according to claim 1,
Wherein the fourth step is a pattern printing method using a nanoparticle array performed by a micro-syringe. A plastic substrate;
A thin film formed on the plastic substrate by a synthetic resin solution, the synthetic resin having a lower glass transition temperature (Tg) than the substrate;
And a nanoparticle pattern formed by sintering the surface of the thin film at a temperature lower than a glass transition temperature of the substrate. 11. The method of claim 10,
Wherein the thin film is a pattern formed by a nanoparticle array formed of a polystyrene material. 11. The method of claim 10,
Wherein the pattern of the thin film is a pattern formed by a nanoparticle array formed at a recessed angle. 11. The method of claim 10,
Wherein the substrate is a pattern formed by a nanoparticle array formed of a material containing at least one of polycarbonate, polyester, polyethylenenaphthalate, polyetherimide, polyvinylalcohol, polyethylene terephthalate, polyethersulfone, polyetheretherketone, polyimide and glass. delete delete delete delete delete

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