KR102487098B1 - Patterning method of electrode having metal nanowire - Google Patents

Abstract

An object of the present invention is to provide a metal nanowire patterning method capable of increasing the quality reliability of a metal nanowire layer to be patterned even with a minimum amount of metal nanowires without vaporized and consumed metal nanowires. The present invention for this purpose is a forming step of forming a metal nanowire layer on a base substrate; and in a state where the base substrate on which the metal nanowire layer is formed is immersed in a liquid solvent, a laser is irradiated on the metal nanowire layer to remove a part of the metal nanowire layer, and the metal nanowire layer is removed from the metal nanowire layer. A producing step of generating a metal nanoparticle solution in which the particles are dispersed in the liquid solvent;

Description

Metal nanowire patterning method {PATTERNING METHOD OF ELECTRODE HAVING METAL NANOWIRE}

The present invention relates to a method for patterning metal nanowires, and more particularly, to a method for patterning metal nanowires capable of improving the quality of metal nanowires attached to a target substrate while reducing the consumption of metal nanowires used for patterning.

Transparent electrodes are used for various purposes in electronic devices applied to displays such as LCDs and OLEDs, solar cells, touch panels, and sensors.

In general, as the transparent electrode, an indium tin oxide (ITO) film has been widely used. However, as ITO is a typical rare material, its high price has been a factor hindering the price competitiveness of final products. In addition, thin films are broken due to its low brittleness, and high temperatures are required in the thin film formation process to be applied to flexible and stretchable electronic devices. The selection of flexible and stretchable substrates that can be used according to the application is very narrow. Therefore, much interest and research are being conducted as an electrode material that can replace ITO.

As an alternative to ITO, there is a metal nanowire. A metal nanowire is a structure made of a single crystal of a metal, and has high chemical stability and excellent electrical conductivity and thermal conductivity, so that its application value is very high in various fields requiring electrical, optical, mechanical, and thermal properties. In particular, since silver nanowires (AgNW) have unique high conductivity, high transmittance, low sheet resistance, flexibility and stretchability, they are attracting a lot of attention for their use as transparent electrodes.

However, these metal nanowires still have many problems to be solved for commercialization as a transparent electrode in spite of the excellent properties described above.

First of all, in general, the patterning process mainly uses a so-called photolithography method that goes through photoresist coating, exposure, and etching processes. The photolithography process requires expensive patterning equipment using optics and lasers, so the process is complicated and requires many It costs money.

In particular, since the metal nanowires coated on the target substrate are changed into fine particles through plasma during the patterning process using a laser, and are vaporized and consumed in the air, the capacity of the metal nanowires to be coated on the target substrate increases as the desired patterning area increases. This should be increased, and there is a problem in that the cost is greatly increased due to the increase in the capacity of these raw materials.

Moreover, since metal nanowires such as silver generally have poor mechanical strength and bonding strength between metal nanowires, an additional process for strengthening the bonding strength of the metal nanowire layer by applying additional materials and heat to the patterned metal nanowires is required. However, the cost can be further increased due to the additional materials used in this process.

Therefore, a new type of patterning technology capable of securing price competitiveness and increasing the reliability of a metal nanowire layer to be patterned even with a minimum amount of metal nanowires is required.

Republic of Korea Patent Registration No. 0405977 (Announced on November 14, 2003)

An object of the present invention is to solve the conventional problems, and to provide a metal nanowire patterning method capable of increasing the quality reliability of patterned metal nanowires even with a minimum capacity of metal nanowires without vaporized and consumed metal nanowires. is in

In order to achieve the above object of the present invention, a metal nanowire patterning method according to an embodiment of the present invention includes a forming step of forming a metal nanowire layer on a base substrate; In a state where the base substrate on which the metal nanowire layer is formed is immersed in a liquid solvent, a laser is irradiated to the metal nanowire layer to remove a part of the metal nanowire layer, and the metal nanoparticles removed from the metal nanowire layer. A production step of generating a metal nanoparticle solution dispersed in the liquid solvent; and after the generating step, in a state in which the base substrate on which the metal nanowire pattern is formed is immersed in the metal nanoparticle solution, an electric field is applied to the metal nanowire pattern so as to disperse the dispersed metal nanoparticles in the metal nanoparticle solution. and a reinforcing step of attaching metal nanoparticles to the metal nanowire pattern to strengthen bonding strength of the metal nanowire pattern.

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In the metal nanowire patterning method according to an embodiment of the present invention, in the strengthening step, an electric field applied to the metal nanowire pattern may have a pulse signal.

In the metal nanowire patterning method according to an embodiment of the present invention, the forming step may include: a coating step of applying a metal nanowire solution containing metal nanowires to one surface of a master substrate; a filtration step of removing remaining solutions other than the metal nanowires from the metal nanowire solution applied on the master substrate; a pressing step of pressing the base substrate in close contact with the metal nanowires placed on one surface of the master substrate; and a separation step of separating the mister substrate from the metal nanowires.

In the metal nanowire patterning method according to an embodiment of the present invention, the master substrate may have a plurality of pores, and in this case, the filtering step forms negative pressure on the other surface of the master substrate to form the metal nanowires. The remaining solution may be removed while passing through the pores.

According to the present invention, a metal nanoparticle solution can be produced by irradiating a base substrate on which a metal nanowire layer is formed with a laser in a liquid environment to form a metal nanowire pattern, and dispersing metal nanoparticles consumed in the patterning process in a liquid solvent. Because of this, it is possible to significantly reduce costs by minimizing raw materials consumed in the patterning process.

In addition, by using the metal nanoparticles of the metal nanoparticle solution produced in the patterning process to strengthen the binding force of the metal nanowire pattern, the cost of raw materials required for patterning can be further reduced and the quality reliability of the metal nanowire pattern can be further increased. can

In addition, through the process of forming a pattern and strengthening bonding force performed in a liquid environment, it is possible to simplify and reduce the time of the entire patterning process, thereby reducing costs and significantly improving product yield.

1 is an exemplary diagram illustrating a method for patterning metal nanowires according to an embodiment of the present invention.
Figure 2 is an exemplary view showing an example of the forming step of Figure 1.
FIG. 3 is an exemplary view for explaining the operation of the generating step of FIG. 1 .
4 is an exemplary diagram showing a method for patterning metal nanowires according to another embodiment of the present invention.
5 is an exemplary diagram for explaining the operation of the reinforcement step of FIG. 4 .
FIG. 6 is an exemplary view showing an attachment state of metal nanoparticles according to electric field conditions in the strengthening step of FIG. 4 .

Hereinafter, preferred embodiments of the present invention in which the above-described problem to be solved can be realized in detail will be described with reference to the accompanying drawings. In describing the present embodiments, the same name and the same reference numeral may be used for the same configuration, and additional description accordingly may be omitted.

1 is an exemplary diagram illustrating a method for patterning metal nanowires according to an embodiment of the present invention.

Referring to FIG. 1 , the method for patterning metal nanowires according to an embodiment of the present invention may include a forming step ( S110 ) and a generating step ( S120 ).

The forming step ( S110 ) may be a step of forming the metal nanowire layer 121F on the base substrate 110 .

A transparent material may be used for the base substrate 110, and in this case, the base substrate 110 on which the metal nanowire pattern 121P is formed may be used as a transparent electrode.

Polyethylene terephthalate (PET) may be used as the base substrate 110 . Of course, an opaque material such as polyimide (PI) may be used for the base substrate 110, and various materials may be used without being particularly limited.

Figure 2 is an exemplary view showing an example of the forming step of Figure 1.

The forming step (S110) may include an application step (S111), a filtration step (S112), a pressurization step (S113) and a separation step (S114).

The coating step ( S111 ) may be a step of applying the metal nanowire solution 120 including the metal nanowires 121 to one surface of the master substrate 101 .

Here, the master substrate 101 may be formed of a porous substrate having a plurality of pores.

As the porous master substrate 101, a polymer made of nylon or Teflon may be used. Of course, various materials having a plurality of pores may be used as the porous master substrate 101, and the material is not particularly limited.

In addition, in the application step (S111), the metal nanowire solution 120 is subjected to bar coating, spin coating, doctor blade coating, dispensing, dipping, and drop casting. It can be applied on the master substrate 101 by various methods such as casting).

The filtration step ( S112 ) may be a step of filtering the metal nanowires 121 from the metal nanowire solution 120 .

The filtration step ( S112 ) may be a step of removing the remaining solution excluding the metal nanowires 121 from the metal nanowire solution 120 applied on the master substrate 101 .

When the master substrate 101 is formed as a porous substrate having a plurality of pores, a negative pressure is formed on the other surface of the master substrate 101 using the vacuum generator 30, thereby excluding the metal nanowires 121 and the rest of the solution. Silver may be removed while passing through the pores of the master substrate 101 , and thus only the metal nanowires 121 may exist on the master substrate 101 .

By filtering the metal nanowires 121 from the metal nanowire solution 120 through such a vacuum filtration method, waste of the metal nanowires 121 can be minimized, thereby reducing raw material costs. In addition, the vacuum filtration method also has the advantage of increasing yield by reducing the process time because the drying process can be eliminated or the drying time can be shortened.

The pressing step ( S113 ) may be a step of pressurizing the base substrate 110 by bringing it into close contact with the metal nanowires 121 placed on the master substrate 101 .

While performing this pressing step (S113), the filtration step (S112) may continue to proceed together. That is, while the base substrate 110 is pressed toward the master substrate 101 with the metal nanowires 121 therebetween, the solution remaining on the metal nanowires 121 completely passes through the pores of the master substrate 101. can be removed

The metal nanowires 121 may be compressed through the pressing step ( S113 ), thereby forming the metal nanowire layer 121F.

And, in the pressing step ( S113 ), the metal nanowire layer 121F may be adhered to the base substrate 110 . At this time, the adhesive force between the base substrate 110 and the metal nanowires 121 may be greater than the adhesive force between the master substrate 101 and the metal nanowires 121 .

The separation step ( S114 ) may be a step of separating the master substrate 101 from the metal nanowire layer 121F.

By setting the adhesive force between the base substrate 110 and the metal nanowire layer 121F to be greater than the adhesive force between the master substrate 101 and the metal nanowire layer 121F, the master substrate 101 is made of metal nanowires by a physical external force. 121, and thus a metal nanowire layer 121F may be formed on the base substrate 110.

FIG. 3 is an exemplary view for explaining the operation of the generating step of FIG. 1 .

Referring to FIGS. 1 and 3 , the generating step ( S120 ) may be a step of forming a metal nanowire pattern 121P on the base substrate 110 .

This generating step (S120) may be performed while irradiating the laser 10 in a liquid environment.

That is, the base substrate 110 on which the metal nanowire layer 121F is formed is immersed in the liquid solvent 140 contained in a Petri dish, and the immersed metal nanowire layer 121F is irradiated with the laser 10, thereby making the non-pattern. A metal nanowire pattern 121P may be formed on the base substrate 110 by removing a portion of the metal nanowire layer 121F present in the region.

DI water may be used as the liquid solvent 140, and ethanol or acetone may be included.

When the laser 10 is irradiated while being immersed in the liquid solvent 140, bubbles are generated in the reaction region of the metal nanowires 121 that come into contact with the laser beam, resulting in a bursting cavitation bubble phenomenon. The metal nanowires 121 can be effectively separated and removed from the strong pressure caused by the cavitation bubble phenomenon.

In addition, since thermal conductivity is higher than that of air in a liquid environment, a relatively high-temperature atmosphere can be created in the reaction region between the laser beam and the metal nanowires 121, and thus the metal nanowires 121 are separated and separated more effectively. can be removed

In addition, the metal nanoparticles 141a deformed from the metal nanowires 121 by the reaction with the laser beam may be recovered in a dispersed state in the liquid solvent 140 .

That is, the metal nanowires 121 reacting with the laser beam are transformed into metal nanoparticles 141a through the plasma step and dispersed on the liquid solvent 140, and the petri dish contains the metal nanoparticles 141a. A metal nanoparticle solution 141 may be produced.

In this way, while going through the generation step (S120) according to the present embodiment, the metal nanowire pattern 121P may be formed on the base substrate 110, and at the same time, the petri dish contains the metal nanoparticles 141a. A metal nanoparticle solution 141 may be produced.

The metal nanoparticle solution 141 thus produced may be recycled as a raw material for other processes.

Meanwhile, the base substrate 110 on which the formation of the metal nanowire pattern 121P is completed may be separated from the Petri dish and then subjected to a separate drying process.

This drying process may be performed by supplying a drying gas such as nitrogen gas to the surface of the base substrate 110 on which the metal nanowire pattern 121P is formed.

4 is an exemplary diagram illustrating a method for patterning metal nanowires according to another embodiment of the present invention, and FIG. 5 is an exemplary diagram for explaining the operation of the strengthening step of FIG. 4 .

According to another embodiment of the present invention, the metal nanowire solution 120 recovered in the Petri dish is used as an additional material in a process for strengthening the bonding force of the metal nanowire pattern 121P patterned on the base substrate 110. It can be.

That is, the metal nanowire patterning method according to another embodiment of the present invention may further include a strengthening step ( S130 ).

The reinforcing step (S130) may be performed after the generating step (S120), and may be a step of strengthening the bonding strength of the metal nanowire pattern 121P formed on the base substrate 110.

The strengthening step (S130) according to the present embodiment may be performed by electrophoretic deposition (EPD) in the metal nanoparticle solution 141 generated in the Petri dish.

That is, the base substrate 110 including the metal nanowire pattern 121P, which was previously separated from the Petri dish and dried, is immersed again in the metal nanoparticle solution 141, and the electrophoretic deposition method is performed on the metal nanoparticle solution 141 in this way. As a result, the bonding force of the metal nanowire pattern 121P may be strengthened.

Of course, the drying process for the base substrate 110 on which the formation of the metal nanowire pattern 121P is completed is omitted, and when the above-described generation step (S120) is completed in the liquid environment of the Petri dish, the strengthening step (S130) is immediately performed. You may.

When a voltage is applied from the power supply 30 in a state where the base substrate 110 on which the metal nanowire layer 121F is patterned is immersed in the metal nanoparticle solution 141, the metal nanowire pattern 121P and the metal nanoparticles An electric field is formed in the solution 141, and by this electric field, the metal nanoparticles 141a dispersed in the metal nanoparticle solution 141 may move toward the metal nanowire pattern 121P and be electrodeposited. Accordingly, bonding force of the metal nanowire pattern 121P may be strengthened.

Meanwhile, in the strengthening step ( S130 ), the attachment capacity of the metal nanoparticles 141a to the metal nanowire patterns 121P may be appropriately adjusted according to the purpose of use. That is, the binding force of the metal nanowire pattern 121P may increase in proportion to the attachment capacity of the metal nanoparticles 141a. If a transparent electrode is to be manufactured, the binding force of the metal nanoparticles 141a increases This is because the transmittance of the transparent electrode may decrease.

Meanwhile, the electric field formed in the metal nanowire pattern 121P and the metal nanoparticle solution 141 through the power supply 30 may have a pulse signal.

When an electric field of a pulse signal is formed in the metal nanowire pattern 121P and the metal nanoparticle solution 141, the metal nanoparticles 141a dispersed in the metal nanoparticle solution 141 correspond to the field signal of the metal nanoparticle 141. Vibration characteristics that are close to or spaced apart from the wire pattern 121P are exhibited. During this repeated vibration process, the metal nanoparticles 141a may be uniformly attached to the entire metal nanowire pattern 121P.

Also, in the strengthening step ( S130 ), the attachment capacitance of the metal nanoparticles 141a attached to the metal nanowire pattern 121P may increase in proportion to the strength of the applied electric field.

FIG. 6 is an enlarged view illustrating the attachment state of metal (Ag) nanoparticles according to electric field conditions in the strengthening step. FIG. 6 (a) shows a metal nanowire pattern 121P in a state in which no electric field is formed. 6 (b) to 6 (f) show metal nanowire patterns 121P in a state in which the strength of the electric field is gradually increased.

As illustrated, as the strength of the electric field increases, the attachment capacitance of the metal nanoparticles 141a increases, and accordingly, the bonding force of the metal nanowire patterns 121P may increase proportionally.

Accordingly, the intensity of the electric field may also be set to an appropriate intensity value according to the purpose of using the metal nanowire pattern 121P.

When the strengthening step ( S130 ) is completed as described above, the base substrate 110 on which the metal nanowire pattern 121P is formed may be separated from the Petri dish and then subjected to a separate drying process.

This drying process may be performed by spraying and supplying a drying gas such as nitrogen gas to the surface of the base substrate 110 on which the metal nanowire pattern 121P is formed.

As described above, the present invention irradiates the base substrate 110 on which the metal nanowire layer 121F is formed with the laser 10 in a liquid environment to form the metal nanowire pattern 121P, and the metal consumed in the patterning process. Since the metal nanoparticle solution 141 can be produced by dispersing the nanoparticles 141a in the liquid solvent 140, cost can be significantly reduced by minimizing raw materials consumed in the patterning process.

In addition, by using the metal nanoparticles 141a of the metal nanoparticle solution 141 produced in the patterning process to strengthen the bonding force of the metal nanowire pattern 121P, the cost of raw materials required for patterning can be further reduced, and the metal Quality reliability of the nanowire pattern 121P may be further increased.

In addition, through the process of forming a pattern and strengthening bonding force performed in a liquid environment, it is possible to simplify and reduce the time of the entire patterning process, thereby reducing costs and significantly improving product yield.

As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but those skilled in the art can make various modifications to the present invention within the scope not departing from the spirit and scope of the present invention described in the claims below. may be modified or changed.

110: base substrate
121: metal nanowire
121F: metal nanowire layer
121P: metal nanowire pattern
140: liquid solvent
141: metal nanoparticle solution
141a: metal nanoparticles

Claims (5)

A forming step of forming a metal nanowire layer on a base substrate;
In a state where the base substrate on which the metal nanowire layer is formed is immersed in a liquid solvent, a laser is irradiated to the metal nanowire layer to remove a part of the metal nanowire layer, and the metal nanoparticles removed from the metal nanowire layer. A production step of generating a metal nanoparticle solution dispersed in the liquid solvent; and
It is performed after the generation step,
In a state where the base substrate on which the metal nanowire pattern is formed is immersed in the metal nanoparticle solution, an electric field is applied to the metal nanowire pattern to disperse the metal nanoparticles dispersed in the metal nanoparticle solution into the metal nanowire pattern. A method for patterning metal nanowires, characterized in that it comprises a; reinforcing step of strengthening the bonding force of the metal nanowire pattern by attaching to the metal nanowire pattern. delete According to claim 1,
In the reinforcement step,
Metal nanowire patterning method, characterized in that the electric field applied to the metal nanowire pattern has a pulse signal. According to claim 1,
The formation step is
A coating step of applying a metal nanowire solution containing metal nanowires to one surface of the master substrate;
a filtration step of removing remaining solutions other than the metal nanowires from the metal nanowire solution applied on the master substrate;
a pressing step of pressing the base substrate in close contact with the metal nanowires placed on one surface of the master substrate; and
Metal nanowire patterning method comprising a; separation step of separating the master substrate from the metal nanowires. According to claim 4,
The master substrate has a plurality of pores,
The filtration step is
The method of patterning metal nanowires, characterized in that by forming negative pressure on the other surface of the master substrate, the remaining solution except for the metal nanowires is removed while passing through the pores.

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