WO2014148726A1

WO2014148726A1 - Manufacturing method for metal electrode

Info

Publication number: WO2014148726A1
Application number: PCT/KR2013/011658
Authority: WO
Inventors: 이동현; 이동은
Original assignee: 단국대학교 산학협력단
Priority date: 2013-03-18
Filing date: 2013-12-16
Publication date: 2014-09-25
Also published as: KR101270803B1

Abstract

A method of forming a metal electrode having a tree shape or a root shape is disclosed. A crystal grain pattern is formed by recrystallizing an aqueous solution of a dissolved salt. The crystal grain pattern is transcribed to a second substrate, and the crystal grains of the salt are dissolved in a water fraction. The second substrate is detached from the first substrate together with the dissolution in the water fraction. The second substrate, to which the pattern has been transcribed, is filled with a conductive ink comprising a metal, and the pattern is transcribed to a third substrate by an imprinting process.

Description

Manufacturing method of metal electrode

The present invention relates to a method of manufacturing a metal electrode, and more particularly, to a method of manufacturing a metal electrode that can ensure a light transmittance using a fine pattern, and can secure excellent conductivity.

Electrodes are used as channels for supplying electrical energy to various electronic devices such as semiconductors, cells, solar cells, or light emitting diodes. A bias is applied between at least two electrodes to initiate operation, or the electronic devices are operated in such a manner that a constant voltage is induced at the two electrodes.

Electrodes applied to these electronic devices have various material and configuration features. The characteristics required for the electrode may require high processability, light transmittance or surface roughness depending on the inherent characteristics of the electronic device along with high conductivity.

For example, in the case of an electrode applied to a solar cell, it is required to be formed evenly distributed on the front surface of the laminated structure in which electrons are transmitted with high light transmittance. Therefore, a metal mesh structure may be used as the electrode applied to the solar cell, or may be used in the form of nanowires. In recent years, the use of graphene and the like has been studied. In addition to the light emitting diode, a conductive oxide is used as the electrode material in order to ensure high light transmittance in addition to the metal electrode. Representative conductive oxides include ITO and the like. ITO has a high light transmittance, but has a relatively low conductivity compared to a metal material, and the unevenness of the bonding with the bonding wire made of gold is a problem during wire bonding due to the roughness of the surface.

As described above, electrodes have been employed in electronic devices with various materials and various configurations. However, in the case of the metal electrode, it is difficult to secure the light transmittance. In order to secure the light transmittance, a mesh-type metal pattern should be formed, which requires a separate lithography process. In addition, although a plurality of wires are sequentially stacked to form a mesh-type wire layer, there is a considerable difficulty in applying a metal pattern on a minute area. In addition, transparent oxide conductive oxide is used to secure light transmittance. However, conductive oxide is difficult to be applied to devices due to deposition process and patterning process, and it has lower conductivity than metal material. It is a weak point.

Accordingly, a technique for forming a metal electrode having high light transmittance and high conductivity will be required.

The technical problem to be achieved by the present invention is to provide a method of forming a metal electrode having a fine pattern, high conductivity and light transmittance.

The present invention for achieving the above technical problem, forming a grain pattern of the salt on the first substrate; Transferring the grain pattern of the salt to a second substrate to form a grain transfer pattern; Embedding a conductive ink in the grain transfer pattern of the second substrate; And transferring the conductive ink embedded in the grain transfer pattern to the third substrate.

In addition, the technical problem of the present invention, forming a grain pattern of the salt on the first substrate; Forming a metal layer on the first substrate to fill the grain pattern; And forming a through pattern for dissolving the grain pattern to expose a portion of the surface of the first substrate.

According to the present invention described above, a salt having a high solubility in water is crystallized to form a fine pattern. The formed micropattern has a tree shape or root shape of nano size or micro size. The metal electrode formed by using the formed micropattern has a high light transmittance and secures the inherent conductivity of the metal, which is a conductive material.

In addition, in the manufacturing process of the electrode of the metal material, the crystal grain pattern may be dissolved using moisture to form the pattern. Therefore, the micropattern can be formed at low cost, and the pattern can be formed in a short time, thereby ensuring productivity.

In addition, it is possible to form a metal electrode having a high light transmittance with respect to incident light and having a high conductivity.

1 is a flowchart illustrating a method of forming a metal electrode according to a first embodiment of the present invention.

2 to 8 are perspective views and images for explaining a process of forming a metal electrode according to the manufacturing example of the present invention.

9 is a graph showing the light transmittance of the metal electrode prepared according to the preparation example of the present invention.

10 to 12 are cross-sectional views illustrating a method of forming a metal electrode according to a second embodiment of the present invention.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention.

First embodiment

Referring to FIG. 1, a grain pattern of salt is formed on a first substrate (S110). Grain patterns are formed by recrystallization of salts and have a tree shape or root shape.

To form the grain pattern of the salt, the salt is dissolved in water to form an aqueous solution, and the aqueous solution is coated on the first substrate. The salt dissolved through the drying of water is recrystallized to form a grain pattern having a specific shape. The formed crystal pattern is formed in a convex shape protruding on the first substrate.

Subsequently, the grain pattern of the salt formed on the first substrate is transferred to the second substrate (S120). Transfer to the second substrate is accomplished by forming a polymer substrate on the first substrate on which the grain pattern of the salt is formed and dissolving the salt through the supply of moisture. Thus, the patterned salt is dissolved and removed through the supply of moisture, and the second substrate is peeled off from the first substrate. Since the crystal grain pattern of the salt is transferred on the peeled second substrate, a pattern transferred in a concave shape recessed from the second substrate is formed.

Subsequently, the conductive ink is embedded in the recessed concave shape of the second substrate (S130). The conductive ink includes conductive metal particles. For example, conductive particles of silver or gold are included in the conductive ink and filled in the recessed pattern.

In addition, the second substrate filled with the conductive ink is bonded to the third substrate, and the pattern of the conductive ink filled through the imprinting process is transferred to the third substrate (S140). Through this, the conductive pattern formed on the third substrate has the same shape as the crystal grain pattern of the salt formed on the first substrate and is transferred onto the third substrate.

Production Example

Referring to Figure 2, an aqueous solution in which salt is dissolved is prepared. The salt is Na ₂ CO ₃ . Also, the concentration is set at 0.01 wt% to 5 wt%. When the concentration of the salt is less than 0.01wt%, excessive time is required for the formation of the grain pattern of the salt, or the spacing between the grain patterns becomes wider and difficult to use as an electrode. In addition, when the concentration of the salt is more than 5wt%, the gap between the patterns is very narrow due to the high concentration, there is a problem that the connection between the patterns can not be secured to secure a predetermined light transmittance.

The prepared aqueous solution is coated on the first substrate 100. Coating is carried out by various methods such as spraying an aqueous solution or spin coating. In addition, the material of the first substrate 100 is not particularly limited, and various materials may be applied. Therefore, any material may be used as long as the material has a surface flatness for formation of a grain pattern of the salt in the drying process of water. In this manufacturing example, a silicon substrate is used.

A drying process is performed on the aqueous solution coated on the first substrate 100. The drying process is for evaporation of moisture is carried out at room temperature or less than 100 ℃. The recrystallization of the salt is induced on the first substrate 100 with the evaporation of moisture. Thus, a tree-shaped or root-shaped crystal grain pattern 110 is formed.

FIG. 3 is an image showing a state in which Na ₂ CO ₃ is coated on a first substrate made of silicon at a concentration of 0.15 wt% and recrystallized.

Referring to FIG. 3, it can be seen that the salt crystal pattern 110 is formed on the first substrate 100 made of silicon through a drying process of about 30 minutes at a room temperature of 25 ° C. FIG. In addition, it can be seen that the grain pattern 110 of the formed salt has a root shape or a tree shape in a state of being physically connected to each other.

Referring to FIG. 4, a second substrate 200 is formed on the first substrate 100 on which the grain pattern 110 is formed. The second substrate 200 serves as a mold for transferring the pattern. To this end, poly (dimethyl siloxane) (PDMS) and a curing agent are mixed on the first substrate 100, and the mixed solution is dropped onto the first substrate 100 and cured. Through this, the flexible second substrate 200 of the PDMS material may be formed.

Since the grain patterns 110 formed on the first substrate 100 have an embossed aspect, grain transfer patterns are formed on the second substrate 200 of the PDMS material in an intaglio form.

Subsequently, referring to FIG. 5, the first substrate 100 and the second substrate 200 are supplied with water to separate the first substrate 100 and the second substrate 200 from each other. Since the grain grain pattern of the salt is water-soluble, the grain grain pattern of the salt formed between the first substrate 100 and the second substrate 200 is dissolved by supplying moisture. Therefore, the second substrate 200 can be easily separated from the first substrate 100. The supply of moisture may be achieved by immersing the first substrate 100 and the second substrate 200 in moisture.

In addition, a grain transfer pattern 210 formed in an intaglio pattern is formed on the second substrate 200 by bonding the first substrate 100 and the second substrate 200. The grain transfer pattern 210 is a molten grain pattern is transferred to the second substrate 200.

FIG. 6 is an image of a second substrate separated from the first substrate in FIG. 5.

Referring to FIG. 6, the second substrate 200 has a negative grain transfer pattern 210 recessed from the surface due to the dissolved grain pattern.

Referring to FIG. 7, the conductive ink 220 is embedded on the negative grain transfer pattern of the separated second substrate 200. The conductive ink 220 includes silver. First, the conductive ink 220 is coated on the separated second substrate 200. The conductive ink 220 is applied to the entire surface of the second substrate 200 through the coating. Subsequently, dragging the second substrate 200 through a brush or planarized glass removes the conductive ink on the second substrate 200 except the negative grain transfer pattern. Therefore, the conductive ink 220 is embedded on the negative grain pattern. In addition, a separate drying process for the embedded conductive ink 220 may be performed.

Referring to FIG. 8, the second substrate 200 of FIG. 7 is applied to the third substrate 300. The conductive ink 220 filling the negative grain transfer pattern of the second substrate 200 through the imprinting process may be embossed on the surface of the third substrate 300. Thus, the shape of the crystal grain pattern 110 of the salt of FIG. 3 is transferred onto the third substrate 300. In particular, the third substrate 300 is combined with the conductive ink 220 to bury the negative grain transfer pattern of the second substrate 200 through a compression or thermocompression process. As a result, an embossed pattern of silver material is formed on the third substrate 300, and the formed embossed pattern maintains the same shape as the crystal grain pattern 110 of the salt formed on the first substrate 100. Finally, by dissolving the second substrate 200 or separating the second substrate 200 from the third substrate 300, a conductive pattern of a metal material formed on the third substrate 300 may be obtained. The formation of can be completed.

The third substrate 300 may be a film that performs a specific function and may be a component of a light emitting diode or a component of a solar cell.

9 is a graph showing the light transmittance of the metal electrode prepared according to the present preparation.

Referring to FIG. 9, a red curve is a graph showing light transmittance when silver is uniformly coated with a thickness of 3 nm on a glass substrate. The blue curve is a graph showing the light transmittance when the glass substrate is used as the third substrate and the transfer is performed at a concentration of 0.15 wt% of Na ₂ CO ₃ .

In the graph, when the electrode is formed in the shape of a tree or root of silver, it can be seen that the light transmittance is higher than that of the thin film having a thickness of 3 nm.

Second embodiment

Referring to FIG. 10, a grain pattern 410 of salt is formed on the first substrate 400. The grain pattern 410 is formed by recrystallization of salts and has a tree shape or a root shape.

To form the grain pattern 410 of the salt, the salt is dissolved in water to form an aqueous solution, and the aqueous solution is coated on the first substrate 400. The salt dissolved through the drying of water is recrystallized to form a grain pattern 410 having a specific shape. The formed crystal pattern 410 is formed in the shape of an embossed protrusion on the first substrate 400.

Referring to FIG. 11, a metal layer 420 is formed on the first substrate 400. The metal layer 420 is formed by filling the crystal grain pattern 410 protruding in an embossed shape on the first substrate 400. However, when the normal high temperature metal deposition process is performed, the shape of the crystal grain pattern 410 of the salt may be damaged. Therefore, the metal layer 410 is preferably formed through a solution process such as spin coating or spraying of conductive ink. When the above-described solution process is performed, the metal layer 420 may not be formed on the side of the crystal pattern 410 having an embossed shape, and may be partially exposed.

Referring to FIG. 12, a dissolution process for the first substrate 400 on which the metal layer 420 is formed is performed. Since the grain pattern of the salt formed in FIG. 10 has high solubility in water, the grain pattern of the salt is removed by supplying water to the first substrate 400. Therefore, the metal layer formed on the crystal grain pattern is also removed. As a result, a part of the first substrate 400 below the dissolved crystal grain pattern is exposed, and a through pattern 430 in which the metal layer is not formed is formed. In addition, the metal layer 420 on which the grain pattern is not formed remains.

Through the above-described second embodiment, the grain pattern of the salt formed on the first substrate is removed, and the remaining portion on the first substrate is formed of a metal layer. Thus, the formed metal layer has a tree-shaped or root-shaped space. When the formed metal layer acts as a metal electrode, the metal electrode can secure a predetermined light transmittance.

In the present invention described above, a salt having high solubility in water is crystallized to form a fine pattern. The formed micropattern has a tree shape or root shape of nano size or micro size. The metal electrode formed by using the formed micropattern has a high light transmittance and secures the inherent conductivity of the metal, which is a conductive material.

Claims

Forming a grain pattern of a salt on the first substrate;

Transferring the grain pattern of the salt to a second substrate to form a grain transfer pattern;

Embedding a conductive ink in the grain transfer pattern of the second substrate; And

Transferring the conductive ink embedded in the grain transfer pattern to a third substrate.
The method of claim 1, wherein forming the grain pattern of the salt,

Coating an aqueous solution in which the salt is dissolved on the first substrate; And

Evaporating water in the coated aqueous solution and inducing recrystallization of the salt.
The method of claim 2, wherein the salt is Na 2 CO 3 .
The method of claim 2, wherein the concentration of the salt in the aqueous solution is 0.01wt% to 5wt%.
The method of claim 1, wherein the forming of the grain transfer pattern on the second substrate comprises:

Forming a mixed solution of PDMS and a curing agent;

Introducing the mixed solution onto the first substrate to form a flexible second substrate, and forming the intaglio crystal transfer pattern recessed from the surface of the second substrate; And

And separating the second substrate on which the grain transfer pattern is formed from the first substrate.
The method of claim 5, wherein the separating of the second substrate from the first substrate comprises dissolving the crystal grain pattern by introducing moisture into the first substrate and the second substrate. .
The method of claim 1, wherein the filling of the conductive ink in the grain transfer pattern comprises:

Coating a conductive ink on the second substrate; And

And dragging the second substrate coated with the conductive ink.
8. The method of claim 7, wherein the conductive ink comprises silver.
The method of claim 1, wherein the grain pattern has a root shape or a tree shape.
Forming a grain pattern of a salt on the first substrate;

Forming a metal layer on the first substrate to fill the grain pattern; And

Dissolving the crystal grain pattern to form a through pattern exposing a portion of the surface of the first substrate.
The method of claim 10, wherein forming the grain pattern of the salt,

Coating an aqueous solution in which the salt is dissolved on the first substrate; And

Evaporating water in the coated aqueous solution and inducing recrystallization of the salt.
The method of claim 11, wherein the salt is Na 2 CO 3 .
12. The method of claim 11, wherein the concentration of the salt in the aqueous solution is 0.01wt% to 5wt%.
The method of claim 10, wherein the grain pattern has a root shape or a tree shape.
The method of claim 10, wherein dissolution of the grain pattern is achieved through supply of moisture.