KR20150041354A - High conduction flexible transparent electrodes formation methods - Google Patents

Abstract

The present invention relates to a method for forming highly-conductive flexible transparent fine electrodes. A metal pattern formation method includes: a step of applying photo-resistor on the surface of a substrate; a step of forming a pattern on the surface of the substrate on which the photo-resistor is applied; a step of backing the substrate on which the photo-resistor is applied; an electrode formation step of coating the entire surface of the baked substrate with conductive ink to form conductive electrode patterns corresponding to the pattern; a step of performing thermal treatment on the substrate on which the conductive ink is coated; and a step of removing the coated conductive ink on the remaining area except for the pattern through a lift-off scheme from the thermal-treated substrate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a high-

The present invention relates to a method of forming a highly conductive flexible micro-transparent electrode, and more particularly, to a method of forming a metal pattern capable of improving physical properties of a flexible substrate and maximizing conductivity.

As electronic technology and information technology continue to evolve, the proportion of electronic devices in everyday life, including work environments, is steadily increasing. In recent years, the kinds of electronic devices have become very diverse. Portable electronic devices such as notebook computers, mobile phones, portable multimedia players (PMPs), tablet PCs, and the like are being poured out with new design devices with new functions every day.

As the types of electronic devices to be encountered in everyday life are gradually diversified and the function of each electronic device becomes more sophisticated and complicated, there is a need for a user interface that can be easily learned by a user and can be intuitively manipulated. A touch panel device has attracted attention as an input device capable of satisfying such a requirement, and has already been widely applied to various electronic devices.

In particular, a touch screen device, which is the most common application of a touch panel device, senses a touch position of a user on a display screen and performs overall control of the electronic device including display screen control using information on the sensed contact position as input information . In addition, with the popularization of such a touch screen device, in the manufacture of a touch screen, a capacitance measuring circuit for a touch screen and a capacitive controller semiconductor serving as a touch screen are becoming increasingly important.

The development of various industrial technologies is becoming more advanced, and the competitiveness of technology development is intensifying. Generally, an electrode is used as an essential component used in various device fields such as a touch panel of a display, a solar cell, a display device, and the like. At this time, the electrode is mainly made of oxide-based inorganic material, mainly indium tin oxide (ITO) and zinc oxide (ZnO).

Accordingly, a variety of techniques for developing electrode patterns are being developed. First, an electrode pattern is formed using a Graphene material. The use of the fp pin is advantageous in that it can produce high transparency and flexible devices, but it has a disadvantage in that it is difficult and physically weak in the conventional semiconductor process due to the mono layer structure. Studies on the reduction of resistance to large area graphene are under way.

Second, we deal with organic polymer PEDOT: PSS electrode with high flexibility. This has advantages of easy large-scale process and low unit cost. However, due to the characteristics of the organic polymer, the stability to light is very low. This problem is related to the stability of the device, and therefore, the application of the device is limited.

The third method is to form an electrode using Ag Nano Fiber. Although a lot of research has been carried out with the large area process being easy, high flexibility, and low resistance of Ag nano fiber, it is difficult to apply the practical device due to contact resistance, haze phenomenon and planarization problem of high Ag nano fiber.

The fourth method is Metal Mesh method using ink printing method. Since the transmittance can be adjusted according to the open rate of the lower substrate, the transmittance can be easily controlled and the conductivity of the metal is also excellent with a low resistance.

In addition, the flexibility is very good due to the characteristics of the mesh structure, which has many advantages as a next generation transparent electrode. However, the ink printing method has disadvantages in that it has a limited line width (~ 10 um), and as the area of the lower substrate is increased, the processing time is increased.

In addition, the conventional ink-jet printing method is only possible for a mesh of a simple lattice structure (x-axis, y-axis), and there is a large restriction on the line width of the metal line depending on the ink concentration and the nozzle size. The limitation of the line width is difficult to control the resistance, and the migration of the metal wire occurs due to the concentration of current, which causes durability problems. In addition, since the process time increases proportionally to the substrate size, it is not suitable for a large area process.

KR 10-2006-0135430 KR 10-11076860 KR 10-11578540 KR 10-11793340

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a technically improved pattern forming method through physical balance of the line width and the overall shape of the pattern and easiness of the process.

Therefore, the present invention forms a conductive pattern by forming a pattern corresponding to an electrode through patterning on a surface of a substrate, coating the conductive ink on the patterned surface and removing the conductive ink, thereby improving the physical stability of the conductive pattern, And an object of the present invention is to provide a method of forming an electrode capable of ensuring high conductivity.

According to another aspect of the present invention, there is provided a method of forming a transparent electrode on a substrate, comprising the steps of: forming a pattern on the surface of the substrate; coating a conductive particle on the patterned surface to form a conductive A second step of coating the transparent electrode pattern, and a third step of coating the conductive particles and removing the remaining region outside the conductive transparent electrode pattern region to form a conductive transparent electrode pattern.

The first step may include a step of cleaning and surface-treating the transparent electrode pattern to be stably formed on the base layer on which the conductive transparent electrode pattern is to be formed, and a step of forming a pattern corresponding thereto to form the conductive transparent electrode And a second cleaning step and a second surface treatment step for stably forming a transparent electrode pattern on an underlying layer on which a conductive transparent electrode pattern is to be formed, Baking the coated conductive particles to form a physical, electrically conductive transparent electrode; and removing the region except for the conductive transparent electrode pattern region to form a final conductive transparent electrode, In the third step, after the final conductive transparent electrode is formed, Further comprising the step of washing.

In addition, the first step may include cleaning and surface-treating the transparent electrode pattern to be stably formed on the base layer on which the conductive transparent electrode pattern is to be formed, forming a corresponding pattern to form the conductive transparent electrode And a second cleaning step and a second surface treatment step for stably forming the transparent electrode pattern on the base layer on which the conductive transparent electrode pattern is to be formed, and the second step includes a step of coating the conductive particles And a baking step of baking the coated conductive particles to form a physical, electrically conductive transparent electrode. In the third step, the applied conductive transparent electrode is wet-etched using the pattern formed in the above step as a mask And removing the mask pattern used in the wet etching.

In addition, the step of forming the transparent electrode pattern may be formed by any one of Imprint, Photo lithography, Stepper, and EUV lithography.

Also, the transparent electrode pattern forming step may be implemented by any one of spin coating, bar coating, printing, sputtering, and evaporation methods for coating the conductive particles.

The transparent electrode pattern forming step is formed using spin coating and has a coating condition of 3 to 10 seconds at 300 to 1000 rpm.

In the transparent electrode pattern forming step, an electrode is coated using any one of conductive particles of a metal particle, a conductive polymer, and a metal ink.

After the step of forming the transparent electrode pattern, one or two or more of a heat treatment process, a plasma process, and a laser irradiation process may be performed to improve conductivity and substrate adsorption.

The baking may be performed at 150 to 170 degrees for 4 to 6 minutes.

The transparent electrode pattern forming method may further include the steps of applying a photoresist to the substrate surface, forming an electrode pattern on the surface of the substrate coated with the photoresist, and baking the substrate coated with the photoresist Forming a conductive transparent electrode pattern corresponding to the pattern by coating conductive ink on the entire surface of the baked substrate; baking the substrate coated with the conductive ink; And removing the conductive ink coated on the region other than the conductive transparent electrode pattern on the heat-treated substrate.

The step of forming the pattern may be performed by any one of Imprint, Photo lithography, Stepper, and EUV lithography.

Also, the transparent electrode pattern forming step may be implemented by any one of spin coating, bar coating, printing, sputtering, and evaporation methods for coating the conductive particles.

The transparent electrode pattern forming step is formed through spin coating and has a coating condition of 3 to 10 seconds at 300 to 1000 rpm.

In the transparent electrode pattern forming step, an electrode is coated using any one of conductive particles of a metal particle, a conductive polymer, and a metal ink.

After the step of forming the transparent electrode pattern, one or two or more of a heat treatment process, a plasma process, and a laser irradiation process may be performed to improve conductivity and substrate adsorption.

The baking may be performed at 150 to 170 degrees for 4 to 6 minutes.

The present invention, which is constituted and operated as described above, can satisfy a high transparency, electric conductivity and flexibility as compared with an electrode manufactured through conventional processes, and can be applied to electrode materials such as touch screens, transparent displays and solar cell electrodes Feature.

In addition, since the roll-to-roll process is possible, the yield is improved and various meshes are formed, which is advantageous in the uniformity of electrode conduction.

In addition, the electrodes implemented by the present invention can realize various shapes of meshes and there is no restriction on the line width. Through these advantages, the haze phenomenon of the conventional printing method is reduced and the current flow according to the mesh structure is reduced So that the effect of reducing the migration of the metal can be obtained.

In addition, there is an advantage of adjusting the transmittance and resistance, which are advantages of the mesh structure.

FIG. 1 is a process diagram showing a cross-sectional view of a fabrication sequence of a method for forming a highly conductive flexible micro-transparent electrode according to the present invention,
FIG. 2 is a process chart showing a manufacturing procedure of a method for forming a highly conductive flexible micro-transparent electrode according to the present invention,
3 is an enlarged perspective view of a transparent electrode formed according to the present invention,
4 is a plan view showing a mesh pattern shape of the highly conductive flexible transparent electrode according to the present invention,
Figs. 5 to 8 are optical photographs of a high-conductivity flexible electrode according to the present invention. Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a method for forming a highly conductive flexible micro-transparent electrode according to the present invention will be described in detail with reference to the accompanying drawings.

A method of forming a highly conductive flexible micro-transparent electrode according to the present invention includes the steps of: applying a photoresist to a surface of a substrate; forming a pattern on the surface of the substrate to which the photoresist is applied; A step of baking the substrate coated with the photoresist; an electrode forming step of forming a conductive electrode pattern corresponding to the pattern by coating conductive ink on the entire surface of the baked substrate; And a step of removing the conductive ink coated on the remaining region in addition to the pattern through a lifetime-off method of the heat-treated substrate.

A method of forming a metal pattern according to the present invention is characterized in that a resist pattern is formed on a substrate to form an area for forming an electrode through a resist and then a conductive ink is coated thereon to coat the surface, And the electrode is formed by a lift-off method in which only the part is left and the remaining area is removed. Thus, a clearer electrode can be formed through the resistor pattern.

In particular, the present invention is characterized in that electrodes are formed by using a life-off method in which a resist pattern is formed on a substrate film (substrate) and then a conductive ink is coated on a surface having a resist pattern formed thereon. More specifically, a resist pattern is formed on a substrate (substrate) using an Imprint patterning method, and a method of selective surface modification of the surface of the lower substrate through atmospheric pressure plasma treatment is provided. The surface of the selective substrate is coated with Ag ink and the curing process is performed. The coated substrate is subjected to a wet process (lift-off) to realize a pattern of metal wires.

FIG. 1 is a cross-sectional view showing a manufacturing process of a method for forming a highly conductive flexible micro-transparent electrode according to the present invention, and FIG. 2 is a process diagram showing a manufacturing procedure of a method for forming a highly conductive flexible micro-transparent electrode according to the present invention. As shown in the figure, an electrode is preferably formed on a surface of a flexible substrate for realizing a touch panel applied to a flexible display. In general, in order to form a transparent electrode on the surface of a PI film which is a flexible substrate, the present invention employs a lift-off method as mentioned above.

The process sequence includes a step of applying a photoresist to the substrate, a step of forming a pattern on the surface of the substrate to which the photoresist is applied, a step of coating the conductive ink with the patterned surface, a step of heat treating the substrate coated with the conductive ink, And removing the conductive ink other than the electrode pattern.

In order to realize this, various techniques can be used to form a mesh pattern using a resist on the surface of the substrate 100 prepared in advance. Examples of the method include an imprint, a photolithography, lithography, a stepper, and EUV lithography. Accordingly, after the photoresist is applied to the substrate surface prepared first, the pattern is formed through one of the processes and baking is performed. In this case, DNR-300, a photoresist, is used in the present invention, and the optimal baking temperature is preferably 150 to 170 degrees for 4 to 6 minutes.

Meanwhile, in the present invention, the surface modification treatment process is carried out for more stable electrode formation (conductive ink coating) through surface modification to the substrate surface on which the pattern is formed. The type of surface modification is modified by various processes such as plasma treatment, surface modification coating, wet chemical treatment, and the like to control the physical or roughness of the surface, thereby improving the adhesion of the conductive ink.

Next, after the surface modification is performed, a conductive material is coated on the surface of the patterned substrate to form a conductive electrode.

The conductive particles for the conductive pattern may be various conductive inks including the form of metal particles, conductive polymer and metal ink, but the most preferred example uses silver (Ag) ink. As a preferable example of the conductive ink, silver (Ag) ink can be used, and an electrode is formed on the surface of the substrate on which a resist pattern is formed by applying one of processes such as spin coating, bar coating, printing method, sputtering and evaporation method.

For example, when the conductive ink is coated on the surface of the substrate on which the honeycomb-shaped resistor pattern is formed, the conductive ink is adsorbed between the hexagonal cells, and the resist pattern serves as a wall, thereby concentrating the conductive ink between the cells during coating .

In an embodiment of the present invention, the electrode forming step is preferably performed using spin coating, and the spin coating may be performed at 300 to 1000 rpm for 3 to 10 seconds.

After forming the conductive pattern, the resist is removed. In the present invention, it is preferable to use acetone as a method of removing a resistor. Among the wet process methods, a resistor removing process can be performed through a dipping method, a Sonic method, a spray method, or the like.

Finally, after the step of forming the conductive transparent electrode pattern, one or more of the heat treatment process, the plasma process, and the laser irradiation process may be performed on the electrode in order to increase the conductivity and the substrate adsorption degree, In addition, the conductivity can be improved.

Therefore, the method of forming lift-off electrodes according to the present invention can minimize the occurrence of cracks as compared with the conventional pattern structure by physically and flexibly coping with the flexible pressure applied to the entire substrate, The transparency of the electrode market can be increased.

3 is an enlarged perspective view of an electrode formed in accordance with the present invention. As shown in the drawing, the honeycomb-shaped mesh pattern is formed first, and then the conductive ink is coated on the surface, so that the electrodes having the honeycomb structure are continuously arranged and formed in a predetermined area.

4 is a plan view showing a mesh pattern shape of a high-conductivity flexible electrode according to the present invention.

The line width of 3 microns or less can be realized through the electrode forming method according to the present invention. The length of one cell side of the honeycomb-structured mesh pattern is less than 50 microns.

Figs. 5 to 8 are images taken by optical photography of a high-conductivity flexible electrode according to the present invention. Fig. FIG. 6 is a photograph taken through an optical microscope in a state where a pattern 200 is formed by coating a photoresistor, and FIG. 7 is a state in which silver ink is coated on the surface of the substrate on which the pattern 200 is formed. The pattern formed by the photoresist coating has a hydrophilic group in the pattern due to the change of the surface modification, so that the silver ink spreads well on the surface, resulting in patterning of the silver ink more effectively as a pattern.

FIG. 8 shows a state in which the coated silver ink is removed, and FIG. 9 shows a state in which the conductive pattern shown in FIG. 8 is magnified through an optical microscope. As shown in the photograph, the conductive pattern of the honeycomb type can be formed uniformly.

According to the present invention configured as described above, the metal electrode pattern is formed in a lift-off manner, the pattern formation process is easy, and the metal pattern of the mesh structure is structurally very stable to minimize cracking, As shown in FIG.

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. On the contrary, those skilled in the art will appreciate that many modifications and variations of the present invention are possible without departing from the spirit and scope of the appended claims. And all such modifications and changes as fall within the scope of the present invention are therefore to be regarded as being within the scope of the present invention.

100: substrate
200: pattern
300: electrode

Claims (16)

A method of forming a transparent electrode on a prepared substrate,
A first step of forming a pattern on the surface of the substrate;
A second step of coating a conductive transparent electrode pattern corresponding to the pattern by coating conductive particles on the patterned surface; And
And a third step of coating the conductive particles and removing the remaining region outside the conductive transparent electrode pattern region to form a conductive transparent electrode pattern. The method according to claim 1,
The first step is a step of cleaning and surface-treating the transparent electrode pattern on the base layer on which the conductive transparent electrode pattern is to be formed, so as to stably form the transparent electrode pattern, and forming a corresponding pattern to form the conductive transparent electrode And a second cleaning and secondary surface treatment to stably form the transparent electrode pattern on the base layer on which the conductive transparent electrode pattern is to be formed,
The second step includes the steps of: coating the conductive particles; baking the coated conductive particles to form a physical, electrically conductive transparent electrode; removing a region excluding the conductive transparent electrode pattern region, And forming a transparent electrode,
The third step further comprises cleaning the final conductive transparent electrode to remove foreign matters remaining in the process after forming the final conductive transparent electrode. The method according to claim 1,
The first step is a step of cleaning and surface-treating the transparent electrode pattern to be stably formed on the base layer on which the conductive transparent electrode pattern is to be formed, and a process step of forming a corresponding pattern to form the conductive transparent electrode And a secondary cleaning and secondary surface treatment for stably forming the transparent electrode pattern on the base layer on which the conductive transparent electrode pattern is to be formed,
The second step includes coating the conductive particles and baking the coated conductive particles to form a physical, electrically conductive transparent electrode,
The third step may include wet etching the applied conductive transparent electrode using the pattern formed in the above step as a mask, and removing the mask pattern used in the wet etching. . The method according to any one of claims 1 to 3, wherein forming the transparent electrode pattern comprises:
A method for forming a highly conductive flexible micro-transparent electrode, which is formed through any one of Imprint, Photo lithography, Stepper, and EUV lithography. The method according to any one of claims 1 to 3,
Wherein the conductive particles are coated by any one of spin coating, bar coating, printing, sputtering, and evaporation methods. The method according to any one of claims 1 to 3,
Wherein the coating is formed using spin coating and has a coating condition of 3 to 10 seconds at 300 to 1000 rpm. The method according to any one of claims 1 to 3,
A method for forming a highly conductive flexible micro-transparent electrode in which an electrode is coated using any one of conductive particles of metal particles, a conductive polymer, and a metal ink. The method according to any one of claims 1 to 3, wherein after the transparent electrode pattern forming step,
A method for forming a highly conductive flexible micro-transparent electrode in which one or more of a heat treatment process, a plasma process, and a laser irradiation process is performed to improve conductivity and substrate adsorption. 4. The method according to claim 2 or 3,
Wherein the baking step is performed at 150 to 170 degrees for 4 to 6 minutes. In the transparent electrode pattern forming method,
Applying a photoresist to the substrate surface;
Forming an electrode pattern on the substrate surface to which the photoresist is applied; And
Baking the substrate coated with the photoresist;
Forming a conductive transparent electrode pattern corresponding to the pattern by coating conductive ink on the entire surface of the baked substrate;
Baking the substrate coated with the conductive ink; And
And removing the conductive ink coated on the heat-treated substrate in a region other than the conductive transparent electrode pattern. 11. The method of claim 10, wherein forming the pattern further comprises:
A method for forming a highly conductive flexible micro-transparent electrode, which is formed through any one of Imprint, Photo lithography, Stepper, and EUV lithography. 11. The method according to claim 10,
Wherein the conductive particles are coated by any one of spin coating, bar coating, printing, sputtering, and evaporation methods. 11. The method according to claim 10,
Wherein the coating is formed through spin coating and has a coating condition of 3 to 10 seconds at 300 to 1000 rpm. 11. The method according to claim 10,
A method for forming a highly conductive flexible micro-transparent electrode in which an electrode is coated using any one of conductive particles of metal particles, a conductive polymer, and a metal ink. 11. The method according to claim 10, wherein after the transparent electrode pattern forming step,
A method for forming a highly conductive flexible micro-transparent electrode in which one or more of a heat treatment process, a plasma process, and a laser irradiation process is performed to improve the conductivity and the substrate adsorption degree. 11. The method according to claim 10,
Wherein the baking step is performed at 150 to 170 degrees for 4 to 6 minutes.

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