KR100877379B1 - Selective metallization process of non-conductive dielectric substrates - Google Patents

Abstract

The present invention relates to a method of forming a metal pattern directly on the surface of a nonconductive dielectric by using a photochemical reaction and a wet surface treatment technology, and more particularly, a specific wavelength after the modification of the surface of the nonconductive dielectric and adsorption of the photosensitive metal compound. The present invention relates to a method of directly forming a metal pattern on a non-conductive dielectric surface by selectively irradiating a surface with a light source having a selective photochemical reaction, adsorbing a noble metal catalyst on an unirradiated portion, and then performing electroless plating.

Photochemical reaction, wet surface treatment technology, non-conductive dielectric, metal pattern

Description

Selective metallization process of non-conductive dielectric substrates

1 is a process flow chart for forming a metal circuit pattern on the surface of a non-conductive material through surface modification treatment and selective photochemical reaction according to the present invention.

FIG. 2 is a measurement diagram for a given light intensity and wavelength when ultraviolet light used in the present invention is irradiated onto a nonconductive material surface.

FIG. 3 is an electron microscope view of a metal circuit pattern having a 20 μm line width formed on a surface of a polyimide film prepared by the method of the present invention. FIG.

FIG. 4 is an electron microscope view of a metal circuit pattern of an actual used RFID formed on a surface of a polyimide film produced by the method of the present invention.

FIG. 5 is an electron microscope view of a metal circuit pattern of an actual used RFID formed on a surface of a polyethylene terephthalate (PET) film manufactured by the method of the present invention.

FIG. 6 is an electron microscope of a copper mesh for electromagnetic shielding in which a metal circuit pattern having a mesh shape having a wire width of 10 μm and an opening region length of 290 μm is formed on a surface of a polyimide film prepared by the method of the present invention. This is the picture observed.

The present invention relates to a method of forming a metal pattern directly on the surface of a nonconductive dielectric by using a photochemical reaction and a wet surface treatment technology, and more particularly, a specific wavelength after the modification of the surface of the nonconductive dielectric and adsorption of the photosensitive metal compound. The present invention relates to a method of directly forming a metal pattern on the surface of a non-conductive dielectric by selectively irradiating a surface with a light source having a selective photochemical reaction, adsorbing a noble metal catalyst on an unirradiated portion, and then electroless plating.

Currently, a technology for implementing a metal circuit pattern is to form a circuit pattern of a certain shape by using a photoresist process on the surface of a non-conductive dielectric substrate on which a thin copper foil is deposited or deposited, and etching copper. Therefore, a method of manufacturing a metal circuit pattern is generally widely used. This traditional metal circuit pattern forming technology is not only composed of complicated and long unit processes, but also has an environmental pollution problem due to expensive equipment investment and corrosive etching solution. At the same time, it is known that the additional investment of expensive and precise equipment along with expensive materials is required or very difficult to realize the microcircuit pattern.

Accordingly, the present inventors have diligently studied to solve the above problems, and when using a photochemical reaction of a metal salt to selectively form a metal circuit pattern layer having a uniform shape on the surface of a nonconductive dielectric material directly in an aqueous solution, It is much simpler and easier to form a fine metal pattern, and it is not only excellent in the performance of the RFID substrate or the electromagnetic wave shielding filter manufactured with the metal pattern, but also can be easily manufactured at a very low cost. Or to form metal circuit patterns with various shapes and functions on the surface of polymer materials for rigid printed circuit boards, or various metal circuit patterns such as electrodes and circuits on glass substrates and polymer substrates for displays. Or used as a packaging substrate for surface-mounting of telecommunication components Confirmed that this reamer, glass and ceramics, can form a non-conductive metal circuit patterns with a variety of features to the dielectric material surface such as a silicon wafer directly, it has been brought to the present invention.

An object of the present invention is a method of forming a fine metal pattern efficiently by a simple and easy process, unlike the conventional metal pattern forming process, and a printed circuit board, display substrate, polymer substrate, surface of excellent performance manufactured using the same This is to provide a packaging substrate for mounting.

In one aspect, the present invention relates to a photochemical reaction and wet surface treatment technology for the formation of a metal pattern directly on the non-conductive dielectric surface, and more particularly, (a) surface modification of the non-conductive dielectric surface with an alkali metal compound ; (b) a photosensitive imparting step of adsorbing a photosensitive metal compound on the surface modified surface; (c) selectively irradiating a light source having a wavelength of 200 to 450 nm to the photosensitive imparted surface; (d) an activation step of substituting and activating a noble metal catalyst to a photosensitive metal compound adsorbed on the unirradiated surface; (e) a method of forming a metal pattern comprising the step of obtaining a metal pattern by using an electroless plating process on the activated surface.

The nonconductive dielectric of the present invention is not particularly limited, but is preferably a polymer such as polyimide, polyester-based polyethylene terephthalate polyester (PET) and aramid film, vision of glass, ceramic, silicon wafer, etc. Refers to the material of the castle. They are mainly used for the manufacture of flexible copper clad laminate (FCCL) and electronic circuit patterns, which are intermediate materials used in flexible printed circuit boards (FPCBs), or for electromagnetic interference. ; EMI) Used for shielding. In the present specification, for convenience, the non-conductive dielectric and the plated body may be used in the same sense.

A process schematic is shown in FIG. 1 as an example of a process for directly forming a metal pattern on a non-conductive dielectric surface by the wet surface treatment technique of the present invention. Hereinafter, the present invention will be described in detail by dividing the present invention step by step with reference to FIG. 1.

The metal circuit pattern forming process of the present invention is a process for removing contaminants such as by-products and dust generated on the surface of the non-conductive dielectric material, which is a plated body, during the manufacturing or handling process, and on the surface of the non-conductive dielectric. Degreasing process is performed by dipping or dispersing the degreasing solution. The process is a process of removing contaminants by immersing or spraying the degreasing solution on the surface of the non-conductive dielectric. The degreasing solution may be an aqueous alkali solution composed of carbonate, phosphate and surfactant. Thereafter, a washing process for washing the degreasing solution and the residue remaining on the surface is performed, and it is preferable to use a method of spraying non-ionized water or ultrapure water at 40 to 50 ° C. in order to increase the cleaning effect.

Next to the degreasing step and the washing step, the surface of the non-conductive dielectric surface is modified with an alkali metal compound. Surface modification is performed by spraying an alkali metal compound on the surface of the non-conductive dielectric or immersing the non-conductive dielectric in the alkali metal compound. In addition, the treatment temperature at the time of surface modification is 20 to 60 ° C, more preferably 20 to 30 ° C, and the non-conductive dielectric surface and the alkali metal compound are sufficiently reacted for 30 seconds to 10 minutes, more preferably 1 to 5 minutes. Surface modification

The alkali metal compound used in the present invention hydrophilizes the hydrophobic nonconductive dielectric surface, and introduces functional groups such as carboxyl groups, amine groups, and hydroxyl groups onto the nonconductive dielectric surface to facilitate adsorption of metal ions. In addition, by forming a fine cavity on the surface of the non-conductive dielectric to increase the surface roughness (roughness), the deposited metal film serves to improve the adhesion to the surface to be plated. Therefore, the surface modification step of the present invention is very important as a pretreatment process for the formation of the fine metal pattern layer of the present invention.

The alkali metal compound of the present invention includes, for example, alkali metal hydroxides, alkaline earth metal hydroxides, and the like, and preferably alkali metal hydroxides. The metal hydroxide includes sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide and the like. In addition, the alkali metal compound of the present invention may further include an ammonium salt and / or an aliphatic amine compound. The ammonium salt is not limited thereto, for example, ammonium hydroxide, ammonium chloride, ammonium sulfate and ammonium carbonate, triethylammonium salt substituted with an alkyl or aryl group, tetraethylammonium salt, trimethylammonium salt, tetramethylammonium salt, trifluoroammonium salt or tetra Fluoroammonium salts and the like. The aliphatic amine compounds include, but are not limited to, methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, ethylenediamine, diethylenetriamine, or urea and hydrazine derivatives.

Sensitizing that absorbs photosensitive metal compounds that cause photochemical reactions by light sources on the surface-modified nonconductive dielectric surface after washing the surface to remove reaction products and treatment solution after surface modification treatment. Perform the process. The photosensitive metal compound is a compound that causes a photochemical reaction by a light source, and preferably a titanium (Ti) salt, molybdenum (Mo) salt, tungsten (W) salt or tin (Sn) salt. By the above process, the photosensitive metal compound is adsorbed onto the surface-modified non-conductive dielectric surface. The deposition time and the concentration of the photosensitive metal compound in the photosensitive metal compound solution of the non-conductive derivative are controlled according to the metal required to form the final metal pattern. The photosensitive metal compound can be adsorbed suitably. As a specific example, the photosensitive metal compound is allowed to react with the non-conductive dielectric surface at a temperature of 20 to 50 ° C., preferably 25 to 35 ° C. for about 30 seconds to 5 minutes, preferably 1 to 3 minutes.

After the photosensitive provision process, a washing process for removing the treatment solution and other contaminants remaining on the non-conductive dielectric surface from the surface and a process of drying the surface are performed.

Next, the photoconductive dielectric surface to which the photosensitive metal compound is adsorbed is blocked using a photomask to block a light source using a photomask in a specific area, that is, a place where a metal pattern layer is to be formed on the surface. A light irradiation process is performed to irradiate a light source and selectively induce an oxidation reaction of the photosensitive metal compound. In the process, the light source uses a light source exhibiting a wavelength range of 200 to 450 nm, and preferably a mercury lamp light source having a main wavelength of 365 nm and 405 nm as shown in FIG. 2. In the case of using a light source having a wavelength of 200 nm or less, there may be a problem such as an increase in manufacturing cost due to an expensive light source device. have. In this case, the irradiation intensity of the light source is 0.5 to 5 J / cm ² , more preferably 1.0 to 1.5 J / cm ² . In addition, the light source may be ultraviolet rays, lasers, X-rays, etc., but preferably ultraviolet rays.

Next, an activation process is performed to displace and adsorb catalyst particles such as noble metals on the photosensitive metal compound adsorbed on the unirradiated surface, that is, the surface on which the metal pattern is to be formed. The noble metal catalyst particles refer to noble metal salts such as Ag, Pd, Pt and Au. By the above process, the noble metal complex ions are substituted and adsorbed by the catalyst particles to the photosensitive metal compound which does not react through ultraviolet irradiation, thereby completing the preparation for forming the metal pattern layer. The activation process can be carried out at 20 to 50 ℃, preferably 20 to 30 ℃ 30 seconds to 5 minutes, preferably 1 to 2 minutes.

After the activation process, the surface of the activated treatment is washed with a washing process, and then an electroless plating process for depositing a metal pattern layer is performed. The electroless plating process may be performed by a conventionally known method. By depositing copper or nickel on the noble metal catalyst adsorbed by the activation process by the electroless plating process, a metal pattern layer having excellent adhesion is formed.

After the formation of the metal pattern layer, it is possible to perform drying by hot air or infrared rays after surface cleaning by the above-described washing process. The metal circuit pattern layer formed by electroless plating may form a final metal circuit pattern layer having a constant thickness and composition according to the applied product and the requirements through an electrocopper plating process, or additionally, an electrocopper plating process after an electroless plating process. . In the electroplating process, it is preferable to use a low stress copper electrolyte to improve adhesion.

Thereafter, the same processes as the washing and drying processes may be performed, and the final desired product may be produced therefrom.

According to the method of the present invention, metal circuit pattern formation of automobiles, electronics, communication, and semiconductor parts can be easily and easily performed as one continuous process. For example, metals on polymer, glass and ceramic surfaces can be used to manufacture electrical and other functional metal patterns of rigid and flexible printed circuit boards (PCBs) and antennas of electronic technology (RFID). Patterns can be formed, hot wires and electrodes on glass for automobiles can be formed, metal patterns such as electrodes and circuits can be formed on glass and polymer materials used for displays (LCD, PDP, LED), etc. Metal patterns may be formed on fibers and polymer materials used as shielding materials.

As another aspect, the present invention relates to a metal pattern manufactured by the above process and a final product comprising the metal pattern.

The final product comprising the metal pattern manufactured by the process of the present invention is, for example, flexible and rigid PCB, electronic technics (RFID) antenna, electromagnetic shielding filter material, display electrode and related Metal circuit fabrication such as metal circuits, but is not limited thereto. Some examples in connection with the product are shown in the Examples.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to explain the present invention in more detail and are not intended to limit the present invention thereto.

Example  One :

According to the process sequence according to the present invention, an electroless copper plating pattern having a pitch of 20 μm was formed on the surface of the polyimide film. The polyimide film was immersed in a solution of a metal compound containing 20 g / l of Sn (II) ions and subjected to photosensitive treatment at 25 ° C. for 2 minutes. After irradiating the surface of the polyimide film using the irradiator, the tin compound was photochemically reacted to form a desired pattern. The copper plating was carried out. The electroless copper plating solution used at this time was copper sulfate 10-12 g / l, nickel chloride 2-3 g / l, sodium carbonate 2-3 g / l, lotel salt 50-60 g / l as complexing agent, formalin 20ml / l as reducing agent 10 ppm to 15 g / L sodium hydroxide as a pH adjuster, and an appropriate ppm of sodium thiosulfate as other additives were used. The electroless copper plating pattern having a 20 μm line width thus formed was observed with an electron microscope (FEI Company, Sirion 400), and this is shown in FIG. 3.

Example 2:

According to Example 1, a real product that is used as a metal pattern of RFID on a polyimide and a polyethylene terephthalate (PET) surface was implemented, and photographs of the metal circuit patterns thus formed are shown in FIGS. 4 and 5.

Example  3:

Under the same conditions as in Example 1, a part used as an electromagnetic wave (EMI) shielding copper mesh used as an electromagnetic shielding material of a display product was manufactured. Accordingly, a copper pattern in the form of a mesh having a metal circuit line width of 10 μm and an opening region length of 290 μm was formed on the surface of the polyimide film, and the metal circuit pattern thus formed was observed with an electron microscope. 6 is shown.

The method of selectively forming a metal pattern of a specific site by the photochemical reaction and wet surface treatment technology of the present invention is a method of etching after pattern formation by a lithography process on a conventional dry film or photoresist, conductive paste such as silver Compared to the method of printing a circuit by inkjet or silk screen using (Paste), the reliability of pattern formation is higher, the process is simpler, it has the advantages of high productivity, low raw material and equipment cost, etc. It may correspond to a fine circuit pattern.

Claims (20)

(a) immersing or spraying an alkali metal compound onto the nonconductive dielectric surface to surface modify the nonconductive dielectric surface; (b) adsorbing a metal component of the photosensitive metal compound on the modified surface to impart photosensitivity to the nonconductive dielectric surface; (c) selectively irradiating a light source having a wavelength of 200 to 450 nm to the photosensitive imparted surface using a photomask; (d) an activation step of substituting and activating the noble metal catalyst particles on the photosensitive metal compound adsorbed on the unirradiated surface of the light source by the photomask; And (e) obtaining a metal pattern on the activated surface by using an electroless plating process Metal pattern forming method comprising a. The method of claim 1, wherein the nonconductive dielectric of step (a) is selected from the group consisting of polymer, glass, ceramic, and silicon wafers. delete The method of claim 1, wherein the alkali metal compound is sodium or potassium hydroxide. The method according to claim 1, wherein an ammonium salt or an aliphatic amine compound, or both thereof is added to the alkali metal compound. 6. The ammonium salt of claim 5, wherein the ammonium salt is selected from the group consisting of ammonium hydroxide, ammonium chloride, ammonium sulfate, ammonium carbonate, triethylammonium salt, tetraethylammonium salt, trimethylammonium salt, tetramethylammonium salt, trifluoroammonium salt and tetrafluoroammonium salt. Way. The method of claim 5 wherein the aliphatic amine compound is selected from the group consisting of methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, ethylenediamine, diethylenetriamine, urea and hydrazine derivatives. According to claim 1, wherein the step (a) is characterized in that the surface modification for 30 seconds to 10 minutes at 20 to 60 ℃. The method of claim 1, wherein the photosensitive metal compound of step (b) is one or more selected from the group consisting of titanium (Ti) salt, molybdenum (Mo) salt, tungsten (W) salt and tin (Sn) salt. How to. The method of claim 1, wherein step (b) is performed at 20 to 50 ° C. for 30 seconds to 5 minutes. The method of claim 1, wherein the step of irradiating the light source of step (c) uses an ultraviolet light source whose main wavelength is 365 nm or 405 nm. The method of claim 1, wherein the step of irradiating the light source of step (c) is a light source irradiating intensity of 0.5 to 5 J / cm ² . delete The method of claim 1, wherein the noble metal catalyst of step (d) is selected from the group consisting of Pd, Ag, Pt and Au. The method of claim 1, wherein the activating step (d) is carried out at 20 to 50 ℃ for 30 seconds to 5 minutes. Metal pattern obtained according to the method of claim 1. Rigid and flexible printed circuit board (PCB) comprising a metal pattern obtained according to the method of claim 1. Electronic technology (RFID) comprising a metal pattern obtained according to the method of claim 1. Electromagnetic shielding filter comprising a metal pattern obtained according to the method of claim 1. An electrode circuit of a display panel comprising a metal pattern obtained according to the method of claim 1.

Images