KR100640694B1 - Method of manufacturing filter for EMI Shield - Google Patents

Abstract

The present invention relates to a method of manufacturing an electromagnetic shielding filter,

Coating a photoresist film on an insulating transparent substrate; Forming a mesh shape pattern on the photoresist film by a photolithography method, and forming a mesh shape pattern surface on the transparent substrate by removing the photoresist film layer of the mesh shape pattern portion; Plasma treatment on the surface of the transparent substrate to activate the annoying mesh-like pattern surface; And removing the residual photoresist film from the surface of the transparent base material and plating the activated pattern surface to form a conductive mesh metal layer.

According to the present invention, the display panel has excellent visibility, and there is an advantage in that a filter can be manufactured without problems of glass substrate breakage, bubble generation, and impurity mixing due to thermocompression bonding. In addition, since the conductive mesh metal layer is adhered to the transparent substrate by plating, an adhesive layer is not necessary, so that a filter having a very thin thickness suitable for light and short reduction of the display panel can be made.

Photoresist, insulating transparent substrate, plasma treatment, activation, conductive mesh metal layer

Description

Electromagnetic shielding filter manufacturing method {Method of manufacturing filter for EMI Shield}             

1 is a schematic cross-sectional view of a filter manufactured by a conventional method for manufacturing a filter for shielding electromagnetic waves;

2 is a process chart showing the electromagnetic wave shielding filter manufacturing method of the present invention;

3 is a schematic cross-sectional view of an electromagnetic wave shielding filter manufactured by the manufacturing method of the present invention.

<Explanation of symbols for the main parts of the drawings>

1 ... tempered glass substrate, 2 ... insulating transparent substrate,

2a ... mesh pattern surface, 3 ... adhesive,

4 ... conductive mesh metal layer, 5 ... mesh film,

6 ... transparent resin layer, 7 ... reflective film,

8, near infrared absorbing film, 9 ... photoresist film,

9a ... mesh shape pattern, 10 ... plasma,

11 ... active surface, 12 ... inactive surface.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electromagnetic shielding filter, and in particular, has excellent visibility of a display panel display screen, greatly prevents the mixing of impurities, and can be manufactured with a thinner thickness. It relates to a manufacturing method of.

Since display panels such as plasma display panels (PDPs) and cathode ray tube devices (CRTs) emit powerful electromagnetic waves harmful to human bodies from the image display surface, it is necessary to provide electromagnetic shielding to prevent radiation of electromagnetic waves.

Therefore, a filter is provided on the front surface of the image display device for the purpose of shielding electromagnetic waves generated from the image display device of the display panel. As the electromagnetic wave shielding filter, a composite material prepared by laminating a mesh-shaped conductive metal layer (hereinafter referred to as a conductive mesh metal layer) on an insulating transparent substrate such as PET is generally used.

FIG. 1 is a schematic cross-sectional view of a filter manufactured by a conventional method for manufacturing an electromagnetic wave shielding filter. Hereinafter, a conventional filter manufacturing method will be described with reference to FIG. 1.

First, the conductive metal layer 4 is bonded to the insulating transparent substrate 2 on the tempered glass substrate 1 by the adhesive 3, and then hot pressed to heat the conductive metal layer 4 to the insulating transparent substrate 2. ) (So-called lamination process). As the conductive metal layer 4, copper foil or nickel foil is usually used, and the copper foil or nickel foil is formed in such a manner that a nodule layer is formed on the surface thereof in order to reduce reflectance and improve adhesion to the insulating transparent base material 2. It is a surface-treated foil subjected to roughness treatment and blackening plating treatment.

Forming a mesh pattern on the conductive metal layer 2 is made by a so-called photolithography method. That is, a photoresist film (not shown) is placed on the conductive metal layer 2, a mesh-shaped photomask is installed thereon, the photoresist film is exposed and developed, and then the photomask is removed to remove the photoresist. A mesh shape pattern is formed on the film.

Subsequently, when the photoresist film and the metal layer other than the pattern portion are removed by etching or the like, only the mesh-shaped conductive mesh metal layer 4 remains, thereby forming a composite filter. The insulating transparent base material 2, the adhesive layer 3, and the conductive mesh metal layer 4 may be collectively referred to as a mesh film 5.

If necessary, functional films such as an antireflection film 7 and a near infrared absorbing film 8 may be attached onto the back surface of the tempered glass substrate 1 and the conductive mesh metal layer 4, respectively.

However, according to the conventional filter manufacturing method as described above, since the conductive metal layer 4 is adhered to the insulating transparent base material 2 by thermocompression bonding, the unevenness on the conductive metal layer is transferred onto the transparent base material, resulting in poor transparency of the transparent base material. There is a problem of lowering the visibility of the display panel display screen by lowering it. Therefore, conventionally, in order to solve this problem, the transparent resin layer 6 is applied on the conductive mesh metal layer 4 and the transparent base material 2 to planarize the unevenness (see FIG. 1), or Japanese Patent Laid-Open No. 2001 As described in -77587, it was necessary to laminate hot melt resins on one or both sides of the conductive mesh metal layer and thermo-compress the insulating transparent base material to flatten the unevenness of the insulating transparent base material by the hot melt resin.

However, even if the visibility of the display screen can be improved by the above process, the process is very cumbersome and there is a risk of damage to the glass substrate due to thermal compression, and there is a risk of bubbles and foreign matters in the lamination process. There is a problem.

Japanese Laid-Open Patent Publication No. 2003-168887 discloses a technique of fluid pressurizing a conductive mesh metal layer and a transparent substrate coated with a transparent resin layer in order to prevent problems caused by thermal compression. The mixing prevention effect is not only slight, but also has a disadvantage of requiring additional transparent resin layer coating.

In addition, the conventional manufacturing method, using a conductive metal layer in the form of a metal foil prepared in advance, there is a technical limit to the thickness of the metal foil to less than 10㎛, as well as the adhesive layer and the transparent resin layer interposed in the filter Since the thickness of the filter becomes thick, there is a problem that cannot meet the tendency of light and thin in recent display panels.

It is an object of the present invention to provide a filter for shielding electromagnetic waves, in which irregularities are not formed on a transparent substrate and excellent in visibility of a display panel display screen.

Another object of the present invention is to provide a filter for shielding electromagnetic waves, which can greatly prevent bubble generation and mixing of impurities.

Another object of the present invention is to provide a filter for shielding electromagnetic waves of a thinner thickness.

The electromagnetic wave shielding filter manufacturing method of the present invention for achieving the above object,

Coating a photoresist film on an insulating transparent substrate;

Forming a mesh shape pattern on the photoresist film by a photolithography method, and forming a mesh shape pattern surface on the transparent substrate by removing the photoresist film layer of the mesh shape pattern portion;

Plasma treatment on the surface of the transparent substrate to activate the annoying mesh-like pattern surface;

And removing the residual photoresist film from the surface of the transparent base material and plating the activated pattern surface to form a conductive mesh metal layer.

It is preferable that the said conductive mesh metal layer is formed by electroless plating.

Further, it is more preferable that the conductive mesh metal layer is formed by electroplating again after electroless plating.

The conductive mesh metal layer is preferably made of one or more alloys selected from one selected from Ni, Cu, Au, Ag, and Sn.

On the other hand, it is preferable to form a fine copper particle layer or blackening plating layer on the surface of the conductive mesh metal layer, or both.

Hereinafter, the present invention will be described in detail.

The present inventors have studied whether the conductive mesh metal layer can be formed on an insulating transparent substrate without thermal compression in order to solve the problem caused by thermal compression. As a result, it has been noted that the problem caused by thermal compression can be solved by forming the conductive mesh metal layer on the insulating transparent substrate by plating.

However, in order to plate the mesh-shaped metal layer on the insulating transparent base material, it is necessary to first form a mesh-shaped pattern on the insulating transparent base material, and the problem that the metal layer should be plated only on the pattern forming part has to be solved. As a result of earnestly researching on this point, the present inventors have formed a mesh-like pattern directly on an insulating transparent substrate using a conventional photolithography method and activating the surface of the transparent substrate under the pattern forming portion by a so-called plasma treatment. Since only the activated portion can be plated with a conductive metal layer, it was concluded that a desired conductive mesh metal layer can be formed on an insulating transparent substrate without thermal compression.

That is, the present invention completely converts the concept from the conventional technique of adhering a conductive metal foil prepared in advance to an insulating transparent substrate, forming a conductive mesh metal layer by photolithography, and then thermally compressing it, and directly by photolithography on the insulating transparent substrate. Forming a mesh-shaped pattern and activating the plating sites by plasma treatment to form a conductive metal layer only in the activated plating sites, there is a feature that solves the problems caused by thermal compression. For this reason, the filter by this invention does not need an adhesive bond layer between a conductive mesh metal layer and an insulating transparent base material. Therefore, the thickness of the filter can be reduced, and the mesh film of the present invention is composed of only an insulating transparent substrate and a conductive mesh metal layer.

In addition, unlike the conventional method in which the conductive metal foil is subjected to surface treatment in advance (harmonic treatment or blackening treatment) and thermally compressed to adhere the metal foil to the insulating transparent base material, the present invention provides a surface treatment as described above as a post-process after the conductive metal layer is formed. Therefore, there is no problem of uneven transfer as in the prior art. Therefore, the filter according to the present invention does not require the transparent resin layer as in the prior art, so that the thickness of the filter can be further thinned.

In particular, the present invention forms a conductive mesh plating layer by plating, in particular, electroless plating and electroplating, so that the conductive mesh plating layer having a thickness of less than 10 μm can be formed by adjusting the plating conditions, thereby making the thickness of the filter even thinner. There is an advantage.

Referring to Figure 2 will be described in more detail the manufacturing method of the electromagnetic shielding filter of the present invention.

Figure 2 is a process chart showing a method for manufacturing an electromagnetic shielding filter of the present invention.

First, the photoresist film 9 is coated on the insulating transparent base material 2 (Step I).

Next, a mesh pattern 9a is formed on the photoresist film 9 by a photolithography method. According to a conventional photolithography method, when a mesh-like photomask 21 is installed on the film 9 and exposed and developed with ultraviolet rays, the photosensitive film 9 has a mesh-like pattern 9a. (Step II).

When the mesh pattern portion 9a is removed by a chemical solution, a mesh pattern pattern surface 2a corresponding thereto is formed on the transparent substrate 2 (Step III).

Next, the mesh surface of the transparent substrate 2 is subjected to a plasma treatment to activate the pattern surface (Step IV).

The plasma treatment refers to a treatment for increasing the mechanical or chemical adhesion of the surface by acting the plasma 10 on the surface to be treated, and is commonly used for surface treatment of copper foil for printed wiring boards. Plasma can be defined as a fully or partially ionized gas of ions and electrons. When an electric field of sufficient size is applied to the gas, the gas is decomposed and ionized into ions and electrons to form a plasma. Gases used to generate the plasma include nitrogen, oxygen, argon gas, ammonia, methane, ethylene and the like.

The present invention enables the plating layer to be easily formed on the pattern portion by applying a plasma treatment process commonly used in the manufacture of printed wiring boards to activate the mesh pattern surface of the transparent substrate.

When the plasma 10 having high energy is applied to the mesh-shaped pattern surface 2a of the transparent substrate 2, the intermolecular and interatomic bonding forces on the target surface are greatly dropped, resulting in an unstable surface, compared to the non-plasma portion. Relatively other molecules or particles are easily bound to each other.

Concrete plasma processing is performed by disposing the transparent substrate 2 in a plasma chamber (not shown) in a vacuum (several mTorr to several Torr). In a conventional plasma generator, a negatively biased electrode is disposed therein, and when gas is injected from one side, a strong electric field is applied to the electrode to cause free electrons to protrude from the electrode, and the free electrons pass through the gas. At this time, the gas molecules or atoms are ionized to generate the plasma 10. Placing the transparent substrate 2 on the opposite side of the gas flow causes the plasma 10 to act on the pattern portion surface 2a of the transparent substrate to activate the surface of the pattern portion.

At this time, the remaining photoresist film 9 acts as a surface activation inhibiting film, so when the photoresist film 9 is removed with a chemical, the transparent substrate surface of the portion where the film is removed forms the inactive surface 12, The pattern portion surface forms the activation surface 11 (V process).

 Subsequently, when the transparent substrate 2 is plated, the plating layer is not formed on the inactive surface 12, and the plating layer is formed only on the activation surface 11, thereby forming the conductive mesh plating layer 4 (VI process).

As a method of forming the plating layer, there are various methods such as electroless plating, electroplating, sputtering, chemical vapor deposition (CVD), and the like, of which electroless plating is most suitable. Since the transparent substrate is insulative, it is difficult to apply electroplating directly to the pattern portion, and there is a risk of forming a metal layer up to the inactive portion by sputtering or chemical vapor deposition.

Therefore, it is preferable to form an initial plating layer by electroless plating, and after forming the electroless plating layer of a certain thickness, it is not possible to form the plating layer of desired thickness by electroplating.

One or more alloys selected from Ni, Cu, Au, Ag, Sn as the plating metal or one or more alloys selected from these are suitable as the electromagnetic shielding metal layer, and in particular, Ni, Cu and alloys thereof in terms of electromagnetic shielding and economic efficiency Most preferred.

As described above, in the case of forming the conductive mesh metal layer by electroless plating and electroplating, it is possible to manufacture a mesh layer of less than 10 μm, and to precisely control the thickness of the mesh layer by adjusting the plating conditions.

Finally, the surface of the conductive mesh plating layer may be subjected to normal roughening plating to form a fine copper particle layer, or to be blackened plating to form a blackening plating layer, and the roughening and blackening treatment may be sequentially performed. . In addition, the combination of the transparent substrate and the conductive mesh metal layer thus drawn may be a glass substrate or a functional film such as an antireflection film or a near infrared absorbing film, depending on the mode of use.

3 is a schematic cross-sectional view of an electromagnetic shielding filter manufactured by the manufacturing method of the present invention.

 As shown, the electromagnetic wave shielding filter manufactured by the present invention can be seen that the filter thickness is significantly thinner without the adhesive layer 3 and the transparent resin layer 6 of Figure 1, the mesh film of the present invention ( 5 ') consists only of an insulating transparent substrate 2 and a conductive mesh metal layer 4.

Hereinafter, the present invention will be described in detail through examples. However, the following examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not limited to the following examples according to the gist of the present invention.

Example 1

After coating the photoresist film 9 on the PET film as the insulating transparent base material 2, and forming the mesh pattern 9a on the photoresist film by photolithography, the photoresist film of the mesh pattern part is organic. By removing with a solvent, the mesh-shaped pattern surface 2a of a transparent base material is exposed. The transparent substrate 2 is disposed in a plasma chamber, and a mixture of nitrogen, oxygen, and argon of 0.1-100 mTorr is converted into plasma to act on the mesh pattern surface 2a to activate the surface. Next, the residual photoresist film 9 is removed, washed with water, and then plated in an electroless nickel plating solution to form an electroless nickel layer having a thickness of 0.030 to 0.05 µm in the pattern portion (activation surface) 11. Subsequently, after washing with pure water, an electrolytic copper layer is electrodeposited on the electroless nickel layer so as to have a thickness of 1 to 12 µm in the electroplating plating solution to form the conductive mesh plating layer 4. Thereafter, the surface of the conductive mesh plating layer was blackened to prepare an electromagnetic shielding filter.

Example 2

All conditions were the same as Example 1 except the electroless copper plating layer was formed using the electroless plating solution as the copper plating solution, and the electrolytic plating layer was formed thereon to form the electrolytic copper layer.

Example 3

All conditions were the same as Example 1 except having made the electroplating layer electrolytic nickel layer.

As described above, according to the present invention, since the conductive mesh metal layer is adhered to the transparent substrate without thermal pressing, the unevenness of the metal layer is not transferred to the transparent substrate, so that the display panel is excellent in visibility, and the glass substrate is damaged by thermal pressing. In addition, there is an advantage that the risk of bubble generation and mixing of impurities is small.

In addition, since the conductive mesh metal layer is adhered to the transparent substrate by plating, no adhesive layer is required, and thus a thin filter can be manufactured.                     

In addition, there is no need for a transparent resin layer for flattening the unevenness transferred to the transparent substrate, so that a transparent resin coating process is unnecessary and a thinner filter can be manufactured.

In addition, an even thinner mesh metal layer can be formed by electroless plating or electroplating, whereby a thin filter having a thickness suitable for light and short reduction of the display panel can be made.

Claims (8)

Coating a photoresist film on an insulating transparent substrate; Forming a mesh pattern on the photoresist film by a photolithography method, and forming a mesh pattern pattern surface on a transparent substrate by removing the photoresist film layer of the mesh pattern; Activating the mesh-shaped pattern surface by performing plasma treatment on the transparent substrate surface; Removing the residual photoresist film from the surface of the transparent base material and plating the activated pattern surface to form a conductive mesh metal layer. delete The method of claim 1, The electroless plating after the electroless plating further forms the conductive mesh metal layer is formed. The method of claim 3, The conductive mesh metal layer is made of Ni, Cu, Au, Ag, Sn or one or more alloys selected from these, the manufacturing method of the electromagnetic shielding filter, characterized in that. The method of claim 4, wherein A fine copper particle layer is formed on the surface of the conductive mesh metal layer. The method of claim 4, wherein The blackening plating layer is formed on the surface of the said conductive mesh metal layer, The manufacturing method of the electromagnetic shielding filter characterized by the above-mentioned. The method of claim 5, A method of manufacturing an electromagnetic shielding filter, characterized in that a blackening plating layer is formed on the fine copper particle layer. An electromagnetic wave shielding filter manufactured by the manufacturing method according to any one of claims 1 to 7.

Images