KR20140113127A - Metal printed circuit board with excellent heat-releasing property - Google Patents

Abstract

The present invention relates to a metal printed circuit board with excellent heat-releasing properties. More specifically, the present invention relates to a metal printed circuit board which has an extended lifetime by excellent heat-releasing properties, has excellent performances, is able to be thinner, is manufactured with the low costs, has a simple manufacturing process, and is environmentally friendly.

Description

[0001] The present invention relates to a metal printed circuit board having excellent heat dissipation characteristics,

The present invention relates to a metal printed circuit board having excellent heat dissipation characteristics. More specifically, the present invention relates to a metal printed circuit board having a long life span and excellent performance due to excellent heat dissipation characteristics, capable of being thinned, low in manufacturing cost, simple in manufacturing process, and environmentally friendly.

BACKGROUND ART An electronic device including a printed circuit board (PCB) has been found to be closely related to performance deterioration such as shortening of life time and malfunction due to temperature rise due to heat generation. Therefore, studies are being made on an efficient heat dissipation technology for avoiding elongation of life of the electronic device and malfunction.

Particularly, in the case of a light-emitting diode (LED) module, the light efficiency of the LED chip is only 20 to 30%, and 70 to 80% of the applied electric energy is emitted as heat. In an LED module having an output power of 0.5 W or more, it is known that epoxy resin (FR-4) substrate, GETEK substrate and the like have low thermal conductivity due to limitations in thermal insulation, and ceramic substrates, and more preferably metal substrates, are used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of a conventional metal printed circuit board. FIG.

As shown in FIG. 1, a conventional metal printed circuit board generally includes a metal base substrate 10 such as aluminum, copper, silicon steel, or galvanized steel with high thermal conductivity, and a polymeric resin An adhesive layer 30 made of a prepreg, an epoxy resin or the like and an adhesive layer 30 for adhering a copper foil 40 forming an electrode on the insulating layer 20, And a copper foil 40 formed in a circuit pattern thereon.

However, since the insulating layer 20 and the adhesive layer 30 have a low thermal conductivity of about 1 to 3 W / mK, the heat generated in the copper foil 40 can be efficiently transferred to the metal base substrate 10) and thus there is a limit in heat radiation. In addition, when the thickness of the metal base board 10 is increased in order to improve the heat dissipation characteristics, the overall thickness of the printed circuit board increases, which limits the use thereof. Since the conventional metal printed circuit board includes the adhesive layer 30 that mediates the copper foil 40 and the insulating layer 20, the manufacturing process becomes complicated and the manufacturing cost increases.

Further, the conventional metal printed circuit board uses a flexible copper clad laminate (FCCL) to form a copper foil 40 of a circuit pattern on the adhesive layer 30 by a photolithography method. In the photolithography method, As a method of implementing a circuit through processes such as coating with a photosensitive layer, exposure, development, etching, and strip, a manufacturing process is complicated, and loss of materials and generation of non-environmental substances in processes such as development, etching, There is a problem caused.

Accordingly, there is a demand for a printed circuit board having excellent heat dissipation characteristics, capable of being thinned, low in manufacturing cost, simple in manufacturing process, and environmentally friendly.

An object of the present invention is to provide a printed circuit board which can prolong its service life due to excellent heat dissipation characteristics and avoid performance deterioration such as malfunction.

It is another object of the present invention to provide a printed circuit board which can be made thin and can be used in a wide variety of applications.

Further, it is an object of the present invention to provide a printed circuit board which is low in manufacturing cost, simple in manufacturing process, and environmentally friendly.

In order to solve the above problems,

A metal base substrate; An insulating layer formed on the metal base substrate and made of an insulating composition comprising an insulating polymeric resin and 40 to 90% by weight of high-heat-releasing inorganic particles based on the total weight of the insulating composition; And an electrode of a circuit pattern formed on the insulating layer.

Here, the high heat-resistant inorganic particles are hexagonal boron nitride (hBN), cubic boron nitride (cBN), a spherical alumina (Al ₂ O _3), alumina fiber, zinc (ZnO), magnesium (MgO), titanate oxide provides a barium (BaTiO _3), strontium titanate (SrTiO ₃₎ and titanium dioxide, the metal printed circuit board comprising the inorganic particles more than one member selected from the group consisting of (TiO _2).

The high heat-radiating inorganic particles preferably have a mean particle diameter of 0.01 to 20 占 퐉 and have a shape of a spherical shape, a rod shape, a plate shape, or a nano-sheet shape. A printed circuit board is provided.

On the other hand, the insulating composition may contain, based on 100 parts by weight of the polymer resin, potassium titanate whisker having a particle size of 10 nm to 100 m, aluminum oxide, silicon nitride, silicon carbide, silicon oxide, boron nitride, boron oxide, At least one reinforcing material selected from the group consisting of whiskers of silica-alumina, zirconia oxide, titanium oxide, carbon nanotubes, nano-diamonds, industrial sapphire, glass fibers, fine powders of carbon fibers, inorganic rust inhibitors, Wherein the metal substrate is a metal substrate.

The insulating polymeric resin includes at least one polymer resin selected from the group consisting of an epoxy resin, a polyimide resin, a polyamide imide resin, and a polyester resin.

Further, the insulating layer is formed by a screen printing method, and has a thickness of 30 to 100 탆 and a thermal conductivity of 8 W / mK or more.

The metal base substrate may be made of aluminum or an aluminum alloy, a copper or a copper alloy, a magnesium or a magnesium alloy, a titanium or a titanium alloy, a melted or plated steel sheet thereof, or a silicon or zinc melted or plated steel sheet, 3 mm. ≪ / RTI >

Here, the surface of the metal base substrate on which the insulating layer is formed is physically or chemically surface-treated to improve adhesion to the insulating layer.

On the other hand, the electrode includes conductive metal particles containing micro-sized silver (Ag) particles and complex-type silver (Ag) particles in a blending ratio of 75:25 to 85:15, To 10 parts by weight of an organic solvent and 5 to 20 parts by weight of an organic solvent.

The micro-sized silver (Ag) particles are in the form of a polygonal plate and have a 50% volume cumulative particle diameter (D ₅₀ ) of 300 to 500 nm according to a laser diffraction scattering particle size distribution measurement method, a 99% A cumulative particle diameter (D ₉₉ ) of 1.5 to 2 탆, and a thickness of 3 to 30 nm.

The micro-sized silver (Ag) particles may be at least one surface treating agent selected from the group consisting of triazole compounds, saturated fatty acids, unsaturated fatty acids, inorganic metal compound salts, organic metal compound salts, polyaniline resins and metal alkoxides And the surface of the metal substrate is subjected to surface treatment.

The complex type silver (Ag) particles may be prepared by mixing silver precursor and at least one branched chain carboxylic acid selected from the group consisting of neohexanoic acid, neoheptanoic acid, isooxanoic acid, isonicotinic acid, neodecanoic acid and neodecanoic acid Wherein the metal layer is produced by a reaction of a metal catalyst.

Further, the conductive metal particles may further include 5 to 10 parts by weight of nano-sized metal particles based on 100 parts by weight of the conductive metal particles.

Also provided is a metal printed circuit board characterized in that the binder is a combination of ethyl cellulose, polyester and polymethyl methacrylate, and the organic solvent is a combination of texanol and diethylene glycol monobutyl acetate.

The electrode is formed by a screen printing method and has a thickness of 10 to 30 탆, a printing resolution of 60 탆 or more, and a line resistance of 8 × 10 ^-6 Ω or less .

The metal base substrate may further include a via hole in which an insulating layer is continuously formed.

And the insulating layer is formed according to a circuit pattern in which the electrode is formed.

The printed circuit board according to the present invention uses a metal base board having a high thermal conductivity and improves the thermal conductivity of the insulating layer formed on the base board and attaches a copper foil on the insulating layer, It is possible to eliminate the heat dissipation property and the heat dissipation property as a whole.

In addition, the printed circuit board according to the present invention eliminates the adhesive layer having a low thermal conductivity and improves the thermal conductivity of the insulating layer, and is formed by a screen printing method instead of the copper foil formed by the conventional photolithography method, And an electrode with excellent heat dissipation property are introduced to minimize the thickness of the metal base substrate, thereby making it possible to reduce the overall thickness and to expand the application.

In addition, the printed circuit board according to the present invention exhibits an excellent effect of reducing the manufacturing cost, simplifying the manufacturing process, and being environmentally friendly by forming the electrodes by the screen printing method instead of the conventional complicated and non-environmental photolithography method.

1 schematically shows a cross-sectional structure of a conventional metal printed circuit board.
2 schematically shows an embodiment of a cross-sectional laminated structure of a metal printed circuit board according to the present invention.
FIG. 3 illustrates various embodiments of a cross-sectional structure of a metal printed circuit board according to the present invention.
4 is an electron microscope (SEM) photograph of an electrode constituting a circuit of a metal printed circuit board according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals designate like elements throughout the specification.

2 schematically shows a cross-sectional structure of a metal printed circuit board according to the present invention. 2, the metal printed circuit board according to the present invention may include a metal base substrate 100, an insulating layer 200, and an electrode 300.

The metal constituting the metal base substrate 100 is not particularly limited, and the higher the thermal conductivity, the better the heat dissipation characteristics. For example, the metal constituting the metal base board 100 may be made of aluminum (thermal conductivity: 238 W / mK) or aluminum alloy, copper (thermal conductivity: 397 W / mK) or copper alloy, magnesium (thermal conductivity: 155.5 W / mK) or a magnesium alloy, a titanium or a titanium alloy, a melted / plated steel sheet thereof, a silicon (thermal conductivity: 138.5 W / mK) or a zinc (thermal conductivity: 119.5 W / mK)

The heat generation characteristic of the metal base board 100 is proportional to the thickness of the metal base board 100. However, since the metal base board 100 is heavier than conventional epoxy boards and ceramic boards, Weight, and miniaturization tendency. Accordingly, one of ordinary skill in the art should appropriately select the thickness of the metal base board 100 according to the use and required characteristics of the printed circuit board, and the thickness may be, for example, 0.5 to 3 mm.

The metal base substrate 100 may be subjected to a surface treatment to secure sufficient adhesion with the insulating layer 200 formed on the base substrate 100, Chemical surface treatment.

Examples of the physical surface treatment include sand blast, dry ice blast, bead blast, shot blast, and grinding, and fine unevenness is formed on the bonding surface, and the specific surface area is widened so that the metal base substrate 100 and the insulation The adhesion to the layer 200 and the durability thereof can be improved.

Examples of the chemical surface treatment include degreasing, etching, chemical treatment, anodizing, PEO (plasma electrolytic oxidation), MAO (microarc oxidation), chromate, phosphate coating, and discharge treatment (plasma). The chemical surface treatment is also advantageous in that the adhesion between the metal base substrate 100 and the insulating layer 200 is improved, and the insulating property, the heat radiation property, and the corrosion resistance are improved, but the cost is considerably higher than the physical surface treatment.

The insulating layer 200 may be formed from an insulating composition containing a polymer resin, and the polymer resin is mostly an electrically insulating material, so that there is no particular limitation. For electricity to pass, there must be free electrons, such as ions or metals, that can move positive electrons and electrons, because polymers are substances that are made up of covalent bonds between carbons and thus have little ability.

The polymer resin may be, for example, an epoxy resin, a polyimide resin, a polyamide imide resin, a polyester resin, or the like. These polymer resins are suitable for use as an insulating layer material of a metal printed circuit board because of their excellent adhesion to metals. Especially, epoxy resins are excellent in heat resistance, chemical resistance, water resistance, and the like. Polyimide resins and polyamide imides Resins have low dielectric constant and excellent insulating properties.

However, the polymer resin generally has a low thermal conductivity of 0.1 to 1 W / mK. Therefore, the insulating layer including the polymer resin can not effectively transmit the heat emitted from the electrode 300 to the metal base substrate 100, thereby deteriorating the overall heat radiation characteristics of the printed circuit board. Further, there is a problem that it is difficult to reduce the thickness of the printed circuit board by increasing the thickness of the metal base board 100 in order to improve the heat radiation characteristics of the printed circuit board due to the polymer resin having a low thermal conductivity. Therefore, in order to improve the heat radiating property of the printed circuit board without increasing the overall thickness of the printed circuit board, the insulating composition may further include high heat-radiating inorganic particles in addition to the polymer resin, The thermal conductivity of the layer 200 can be improved to 8 W / mK or more.

The high heat-resistant inorganic particles are hexagonal boron nitride (hBN), cubic boron nitride (cBN), a spherical alumina (Al ₂ O _3), alumina fiber, zinc (ZnO), magnesium oxide (MgO), barium titanate ( At least one inorganic particle selected from the group consisting of BaTiO ₃ , strontium titanate (SrTiO ₃ ) and titanium dioxide (TiO ₂ ) inorganic particles, preferably hexagonal boron nitride (hBN) inorganic particles, cubic boron nitride cBN) inorganic particles, or a mixture thereof, or a mixture of magnesium oxide (MgO) and alumina fibers.

The boron nitride (BN) exists in three states, but only hexagonal boron nitride (hBN) and cubic boron nitride (cBN) are in a stable state. The hexagonal boron nitride (hBN) can be obtained by subjecting carbon to a crude boron nitride obtained by heating and mixing a mixture of boric acid and urea in a nitrogen gas and heat-treating the mixture in a nitrogen gas. The cubic boron nitride (cBN) Can be obtained by applying hexagonal boron nitride (hBN) at a high pressure of 6 GPa or more and a high temperature of 1500 ° C or more.

The boron nitride (BN) is stable up to 3000 ° C in an inert atmosphere such as a gas or a vacuum, exhibits excellent thermal stability, and exhibits a high thermal conductivity as high as that of stainless steel. In addition, it exhibits significantly higher electric resistance than alumina ceramics with high density / high purity, and is excellent in corrosion resistance and non-toxicity in most organic solvents.

The content of the high heat dissipation inorganic particles may be 40 to 90 wt% based on the total weight of the insulating composition. If the content of the high heat-radiating inorganic particles is less than 40% by weight, desired heat radiation characteristics can not be attained, while if it exceeds 90% by weight, printability and fluidity may be deteriorated. The average particle diameter and shape of the high heat dissipation inorganic particles are not particularly limited. For example, the high heat-radiating inorganic particles may have an average particle diameter of 0.01 to 20 μm and a shape of a sphere, a rod, a plate, or a nano-sheet.

In addition, the insulating composition may further include a curing agent for curing the polymer resin. The curing agent may be different depending on the kind of the polymer resin, and for example, an amine type, phenol type, silane type, organic peroxide curing agent and the like may be added. The content of the curing agent may be about 1 to 10 parts by weight based on 100 parts by weight of the polymer resin.

The polymer resin has excellent electrical characteristics, but has a low mechanical strength and exhibits thermal expansion ten times or more as compared with the metal base substrate 100. Thus, the insulating composition may contain, in addition to the polymeric resin, a potassium titanate whisker having a particle size of 10 nm to 100 탆, aluminum oxide, silicon nitride, silicon carbide, silicon oxide, boron nitride, boron oxide, aluminum nitride, whiskers of silica- And at least one reinforcing material selected from the group consisting of zirconia, zirconia, titanium oxide, carbon nanotubes, nano-diamonds, industrial sapphire, glass fibers, fine powders of carbon fibers, inorganic rust inhibitors and mixtures thereof.

The addition of the reinforcing material can improve the longitudinal and transverse strength, thermal expansion, cracking and sedimentation resistance, durability, insulation and the like of the insulating layer 200. The content of the reinforcing material is 0.01 to 70 parts by weight based on 100 parts by weight of the polymer resin. Weight portion.

The insulating layer 200 is formed on the metal base substrate 200 using the insulating composition by using spraying, airless spraying, electrostatic coating, electrodeposition coating, screen printing, flow coating, spin coating, dipping, roll coating, (Not shown). The insulating layer 200 may be formed to a thickness of 30 to 100 탆 in order to exhibit sufficient insulating properties.

When the insulating layer 200 is formed using screen printing, it is easy to form the insulating layer 200 according to the circuit pattern of the electrode formed on the insulating layer 200, It is possible to minimize the loss of material. When the insulating layer 200 is formed in accordance with a circuit pattern, a space secured between the circuit patterns prevents the insulating layer 200 and the metal base substrate 100 from having different thermal expansion coefficients Can be avoided.

The lower the resistance and the heat generation of the electrode 300, the higher the electric conductivity, the better the heat dissipation characteristics and the thinness of the printed circuit board. The electrode 300 may preferably be formed from a conductive ink / paste or the like including conductive metal particles, and more preferably, by a screen printing method, a conductive ink containing conductive metal particles, a binder, an organic solvent, ≪ / RTI >

The screen printing method comprises applying the conductive ink composition on the insulating layer 200 according to a circuit pattern of an electrode to be formed and firing the applied conductive ink composition at a high temperature to form conductive metal particles And forming an electrode by sintering.

Unlike the conventional photolithography method for forming electrodes, the screen printing method is advantageous in that the process cost is reduced due to the simple process, and the removal of the photosensitive material causing environmental pollutants, the etching of the copper foil, etc. It is also environmentally friendly.

In addition, unlike the conventional ink-jet printing method, since a paste-type conductive ink composition having a relatively high viscosity is used, there is an advantage that the thickness of the electrode to be formed can be secured and the low wire resistance / high electric conductivity can be easily achieved.

Further, since a separate adhesive layer mediating between the electrode and the insulating layer is unnecessary unlike the electrode formation by the adhesion of the copper foil in the past, deterioration of the heat radiation characteristic of the printed circuit board due to the low thermal conductivity of the adhesive layer can be avoided, The forming process is simple and the manufacturing cost of the printed circuit board is reduced.

However, in the conventional conductive ink composition used in the screen printing method, the conductive ink composition applied under an inert gas atmosphere and at a high temperature of about 220 to 350 DEG C is fired to suppress the oxidation of metal particles contained therein, The firing performed under the inert gas atmosphere requires an additional process, and further, the firing of the conductive ink composition at high temperature has caused deformation, particularly shrinkage, of the insulating layer 200.

On the other hand, in the printed circuit board according to the present invention, the conductive ink composition for forming the electrode 300 can avoid or minimize the oxidation of the metal particles contained therein, 300 can be ensured and deformation of the insulating layer 200 can be avoided or minimized.

Specifically, oxidation of the metal particles included in the conductive ink composition can be avoided or minimized, and sufficient electrical conductivity of the electrode 300 can be ensured even at a low temperature of 200 ° C or less, The construction of the conductive ink composition that can be avoided or minimized is as follows.

In the present invention, the conductive metal particles included in the conductive ink composition may include two or more metal particles among metal atoms belonging to groups 10 to 12 of the periodic table. Specifically, the conductive metal particles may include micro-sized metal particles and complex metal particles. Preferably, the micro-sized metal particles may be silver (Ag) particles, and the complex-type metal particles may be complex-type silver (Ag) particles.

Ag (NO ₃ ), Ag ₂ (SO ₄ ), Ag (BF ₄ ), and Ag (BF ₄ ) are used for the silver (Ag) precursor for obtaining the micro- PF ₆ ), Ag ₂ O, CH ₃ COOAg, Ag (CF ₃ SO ₃ ), Ag (ClO ₄ ), AgCl, CH ₃ COCH = COCH ₃ Ag and the like. The silver (Ag) particles can be prepared from the silver (Ag) precursor by a conventional method such as a wet reduction method. For example, a silver (Ag) precursor such as Ag (NO ₃ ) or Ag ₂ (SO ₄ ) is prepared by dissolving silver (Ag) in nitric acid or sulfuric acid, diluted with distilled water, and added with ammonia water or carboxylic acid (Ag) particles can be prepared by preparing a monodispersed silver (Ag) complex by adding a dispersant, reducing the silver complex using a reducing agent, and washing it with an organic solvent and distilled water. have.

The micro-sized silver (Ag) particles may preferably be in the form of a polygonal plate. For example, the (Ag) particles have a D ₅₀ of 300 to 500 nm, a volume cumulative particle size of 50% and a D ₉₉ of 1.5 to 2 μm, which have a volume cumulative particle size of 99% according to a laser diffraction scattering particle size distribution measurement method , And a thickness of 3 to 30 nm.

Particularly, the plate (Ag) according to the present invention, which is distinguished from conventional micro-sized silver (Ag) particles, has a D ₅₀ of 300 to 500 nm and a D ₉₉ of 1.5 to 2 탆, The contact area between the particles increases, which is advantageous for achieving a low line resistance, that is, a high electric conductivity, of the electrode 300 to be formed. In addition, since the plate (Ag) has a thickness of 3 to 30 nm and is nano-sized, the plate is inserted into the gap between the (Ag) grains, and the complex type silver (Ag) Sintering at low temperatures with the particles is possible.

The method for producing the plate (Ag) particles is such that spherical silver (Ag) particles are put into a pulverizer together with a separate pulverizing medium such as zirconia beads, alumina beads and glass beads, A method of pressing and deforming is generally used.

Since the micro-sized silver (Ag) particles are excellent in reactivity and are easily oxidized, it is preferable to use P, Sb, Si, K, Na, Li, Ba, Sr, Ca, Mg, Be, Zn, Pb, Cd, , Sn, Al, Zr, W, Mo, Ti, Co, Ni, Au and the like, or an alloy particle with a triazole compound, a saturated fatty acid, an unsaturated fatty acid, an inorganic metal compound salt, an organic metal compound salt, a polyaniline resin, , And the like.

Further, as the surface treatment agent for treating the surface of the micro-sized silver (Ag) particles for improving the oxidation resistance, the triazole compound may be, for example, benzotriazole or triazole, The above-mentioned unsaturated carboxylic acids such as acetic acid, acetic acid, citric acid, acetic acid, citric acid, acetic acid, acetic acid, Examples of the fatty acid include fatty acids such as acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid, elaidic acid, cetoleic acid, brassidic acid, erucic acid, sorbic acid, linoleic acid, linolenic acid, The inorganic metal compound salt may be, for example, sodium silicate, sodium tartrate, tin sulfate, zinc sulfate, sodium hydroxide, zirconium nitrate, sodium zirconium chloride, zirconium chloride, titanium sulfate, titanium chloride, potassium titanate oxalate, The metal compound salt includes, for example, lead stearate, lead acetate, p-cumylphenyl derivatives of tetraalkoxyzirconium, p-cumylphenyl derivatives of tetraalkoxytitanium, and the like. The metal alkoxides include, for example, titanium alkoxides, zirconium alkoxides, lead alkoxides, Silicon alkoxide, tin alkoxide, indium alkoxide, and the like.

The silver (Ag) particles to be surface-treated with the surface treatment agent may include the silver (Ag) alloy particles and may be dissolved in a solvent capable of dissolving the surface treatment agent, for example, water, an alcohol such as methanol, ethanol, isopropanol Glycol solvents such as ethylene glycol monoethyl ether, carbitol solvents such as diethylene glycol monobutyl ether, and carbitol acetate solvents such as diethylene glycol monoethyl ether acetate. The surface treatment agent is added in an amount of 1 to 90 wt% % Solution of silver (Ag) can be produced by using the surface treatment solution prepared by dissolving the silver (Ag) particles.

On the other hand, the complex-type silver (Ag) particles may be composed of a compound produced by reacting a silver (Ag) precursor with a ligand. Ag (NO ₃ ), Ag ₂ (SO ₄ ), Ag (BF ₄ ), Ag (BF ₄ ), and Ag (BF ₄ ) are examples of the complex type silver (Ag) precursor for obtaining the PF ₆ ), Ag ₂ O, CH ₃ COOAg, Ag (CF ₃ SO ₃ ), Ag (ClO ₄ ), AgCl, CH ₃ COCH = COCH ₃ Ag and the like.

In addition, the ligand may be a hydrocarbon group containing a carboxyl group, an amine-based organic compound, or the like, and may preferably be a branched chain carboxylic acid. The branched chain carboxylic acid may be, for example, neohexanoic acid, neoheptanoic acid, isooctanoic acid, isonicotinic acid, neodecanoic acid, neoundecanoic acid, and the like.

The branched chain carboxylic acids are effective in volume due to the presence of carbon branches, and the distance between complexes, such as straight chain carboxylic acid ligands, can not be adhered. That is, the complex type (Ag) particles formed by the straight-chain carboxylic acid ligands are difficult to dissolve / disperse in the nonpolar organic solvent due to the coordination of polarity because the (Ag) particles form a highly structured and stable structure, while the complex type by the branched chain carboxylic acid ligands Ag) particles have a weak structure, they can be relatively easily dissolved / dispersed in a nonpolar organic solvent.

The complex-type silver (Ag) particles can be stably dissolved / dispersed in a binder, an organic solvent, etc. contained in the conductive ink composition as compared with conventional nano-sized silver (Ag) (Ag) particles, it is advantageous in that the manufacturing process is simple and the manufacturing cost is low as compared with the conventional nano-sized silver (Ag) particles.

The complex type silver (Ag) particles are disposed in a gap between the micro-sized silver particles included in the conductive ink composition including the silver, and the silver (Ag) particles are reduced to silver (Ag) Size silver (Ag) particles by sintering them.

As described above, in the present invention, the conductive ink composition for forming the electrode 300 includes silver (Ag) particles of micro-size as conductive metal particles, preferably silver (Ag) Ag) particles. Since the plate (Ag) particles having micro-sized silver (Ag) particles have a large specific surface area, the contact area between the particles increases, thereby minimizing the voids inside the electrode 300, The ink composition of the present invention is advantageous in achieving a low line resistance, that is, a high electric conductivity, and an appropriate viscosity, thixotropic index, etc. of the ink composition facilitates excellent printing properties and electrode thickness, So that the complex-type silver (Ag) particles disposed in the voids between them can be sintered at a low temperature, and deformation of the insulating layer 200 in which the electrode 300 is formed can be avoided or minimized.

In the present invention, the content of the conductive metal particles contained in the conductive ink composition may be 45 to 80% by weight based on the total weight of the composition. Also, the conductive metal particles may include a combination of micro-sized silver particles and complex-type silver particles, wherein the amount of the micro-sized silver (Ag) particles, based on 100 parts by weight of the conductive metal particles, (Ag) particles may be from 15 to 25 parts by weight, preferably from 20 to 25 parts by weight, based on 75 parts by weight of silver (Ag), and preferably from 75 to 80 parts by weight.

When the content of the micro-sized silver (Ag) particles is more than 85 parts by weight and the complex type silver (Ag) particles are less than 15 parts by weight, sintering between the particles sufficiently It may be difficult to achieve a low line resistance, that is, a high electrical conductivity, of the electrode, such as a high porosity occurring in the electrode without causing micro-sized silver (Ag) particles to be less than 75 parts by weight If the content of the complex-type silver (Ag) particles is more than 25 parts by weight, low-temperature firing can be carried out but excessive shrinkage occurs at the time of electrode formation, or poor printability due to inadequate viscosity of the composition, thixotropic index, A desired thickness can not be attained and a low wire resistance of a formed electrode, that is, high electrical conductivity can not be achieved.

In the present invention, the conductive ink composition may further include nano-sized metal particles in addition to the micro-sized silver (Ag) particles and the complex-type silver (Ag) particles as the conductive metal particles. The nano-sized metal particles may include two or more metal particles, preferably silver (Ag) particles, of metal atoms belonging to groups 10 to 12 of the periodic table.

The nano-sized metal particles may have a particle diameter of, for example, 1 to 50 nm, and the shape thereof is not particularly limited, but may be, for example, a spherical shape, a flat shape, a block shape, a plate shape, a scaly shape, May be spherical, flat, or plate-like. The content of the nano-sized metal particles may be 5 to 10 parts by weight based on 100 parts by weight of the conductive metal particles.

The nano-sized metal particles are disposed in a gap between the micro-sized silver (Ag) particles to promote sintering between the metal particles upon firing, so that a low line resistance of the formed electrode 300, That is, high electrical conductivity.

The conductive ink composition according to the present invention can be produced by uniformly dispersing the conductive metal particles, excellent printability by controlling the viscosity and thixotropic index of the composition, applying / firing the composition on the insulating layer 200 An appropriate binder may be further included to secure close adhesion between the electrode 300 and the insulating layer 200 when the electrode is formed.

The binder is not particularly limited, and examples thereof include cellulose resins such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose and nitrocellulose, polyvinyl chloride resins or copolymer resins, polyvinyl alcohol resins, polyvinyl pyrrolidone resins , Acrylic resin such as polymethyl methacrylate, butyral resin such as vinyl acetate-acrylate copolymer resin and polyvinyl butyral, alkyd resin such as phenol-modified alkyd resin and castor oil fatty acid-modified alkyd resin, epoxy resin, phenol resin , A rosin ester resin, a polyester resin, or a combination thereof. It is preferable to use a polyester resin having high viscosity as the binder in order to secure an excellent printability by controlling the viscosity and the tin value of the conductive ink composition. More preferably, the binder is a mixture of ethylcellulose, A combination of methacrylates may be used.

The content of the binder may be 1.5 to 10 parts by weight based on 100 parts by weight of the conductive metal particles contained in the conductive ink composition. When the content of the binder is less than 1.5 parts by weight, the viscosity and the tin value of the conductive ink composition excessively increase, so that the line resistance of the electrode is increased, the electric conductivity is lowered, the printing property is lowered, However, if the amount is more than 10 parts by weight, precision printing is difficult, and the line resistance of the electrode formed by acting as a resistance component between the conductive particles may be increased and the electric conductivity may be lowered.

The electrode 300 formed by the conductive ink composition may have a different thickness, a printing resolution (line width), or the like depending on the use and required characteristics of the printed circuit board including the electrode 300. For example, And a printing resolution (line width) of 60 mu m or more.

In the present invention, the conductive ink composition is suitable for ensuring uniform dispersion of the conductive metal particles, excellent printability by controlling the viscosity and thixotropic index of the composition, workability in electrode formation, and workability And may further comprise an organic solvent.

The organic solvent is not particularly limited and includes, for example, hydrocarbon solvents such as hexane, cyclohexane and toluene, chlorinated hydrocarbon solvents such as dichloroethylene, dichloroethane and dichlorobenzene, tetrahydrofuran, furan, tetrahydropyran, Cyclic ether solvents such as pyridine, dioxane, 1,3-dioxolane and trioxane, amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide, dimethylsulfoxide, Propanol, 1-butanol, diacetone alcohol, glycol and the like, or a polyhydric alcohol-based solvent such as diethylene glycol, triethylene glycol, triethylene glycol, Solvent, butyl acetate, 2,2,4-trimethyl-1,3-pentanediol monoacetate, 2,2,4-trimethyl-1,3-pentanediol monopropionate, 2,2,4- , 3-pentanediol monobutyrate, 2,2,4-tri Methyl-1,3-pentanediol monoisobutyrate (Tessanol), 2,2,4-triethyl-1,3-pentanediol monoacetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, Diethyleneglycol monobutyl acetate; ether solvents of polyhydric alcohols such as butyl cellosolve and diethyleneglycol diethyl ether; ether solvents such as? -Terpinene,? -Terpineol, myrcene, Terpene solvents such as limonene, dipentene,? -Pinene,? -Pinene, ocimene and pellandrene, and mixtures thereof.

The organic solvent preferably includes a high boiling point organic solvent. When the boiling point of the organic solvent is low during firing to form the electrode, its volatilization proceeds too fast, and the conductive metal particles contained in the applied conductive ink composition are already removed before sintering occurs, have. More preferably, the organic solvent includes a combination of texanol and diethylene glycol monobutyl acetate for ensuring excellent printability by controlling viscosity and tin value of the conductive ink composition as well as processability and workability at the time of electrode formation can do.

The content of the organic solvent may be 5 to 20 parts by weight based on 100 parts by weight of the conductive metal particles contained in the conductive ink composition. When the content of the organic solvent is less than 5 parts by weight, it may be difficult to prepare a paste-type composition for screen printing. On the other hand, when the content is more than 20 parts by weight, the tin value of the conductive ink composition becomes excessively low, And printing may be deteriorated due to bleeding.

In the present invention, the conductive ink composition may further include phosphorus compounds, fluxes, and other additives. The phosphorus-containing compound and the flux can further improve the oxidation resistance of the conductive metal particles contained in the conductive ink composition and the electrical conductivity of the electrode to be formed. The phosphorus-containing compound may be, for example, phosphorus-based inorganic acid such as phosphoric acid, phosphoric acid salt such as ammonium phosphate, phosphoric acid ester such as alkyl phosphate ester or phosphoric acid aryl ester, cyclic phosphazene such as hexaphenoxyphosphazene, have. The phosphorus-containing compound may be 0.5 to 10 parts by weight based on the total weight of the conductive ink composition.

The flux may be, for example, a fatty acid, a boric acid compound, a fluoric compound, a fluoroboric compound and the like, specifically, lauric acid, myristic acid, palmitic acid, stearic acid, sorbic acid, stearic acid, boron oxide, Sodium fluoride, sodium fluoride, sodium borate, lithium borate, potassium borofluoride, sodium borofluoride, lithium borofluoride, acid potassium fluoride, sodium acid fluoride, lithium acid fluoride, potassium fluoride, sodium fluoride, lithium fluoride and the like. The flux may be 0.1 to 5 parts by weight based on the total weight of the conductive ink composition.

Such other additives may be, for example, plasticizers, dispersants, surfactants, inorganic binders, metal oxides, ceramics, organometallic compounds, and the like.

In the present invention, the method of preparing the conductive ink composition is not particularly limited, and the micro-sized silver particles, the complex silver (Ag) particles, the binder and the organic solvent, and optionally the nano- ) Particles, phosphorus-containing compounds, fluxes, and other additives can be prepared by dispersing and mixing the particles using commonly used dispersion and mixing methods.

In the present invention, the conductive ink composition may preferably have a tin value of 4 to 6 depending on the specific conductive metal particles, binders, organic solvents, etc. contained therein and the blending ratio thereof. The conductive ink composition having the tin value of 4 to 6 is printed once to form the electrode 300 on the insulating layer 200 using a general screen printing method and then fired at 220 DEG C or lower for about 15 minutes An electrode having a thickness of 10 to 30 占 퐉, a line width of 60 to 70 占 퐉, and a line resistance of 8 占^10-6 ? Or less can be formed.

As described above, the printed circuit board according to the present invention includes a metal base substrate 100 having a high thermal conductivity instead of a conventional epoxy substrate and a ceramic substrate as a base substrate, By adding the high heat dissipation inorganic particles having high thermal conductivity in addition to the base resin having low thermal conductivity to the insulating composition constituting the layer 200, the overall heat radiation characteristic of the printed circuit board is improved to prolong the life of the printed circuit board, It is not necessary to excessively increase the thickness of the metal base board 100 in order to secure a desired heat dissipation characteristic, thereby making it possible to reduce the thickness of the printed circuit board.

In addition, since the printed circuit board according to the present invention uses a screen printing method that is simple and eco-friendly, unlike the conventional photolithography method, when the electrode 300 is formed on the insulating layer 200, the manufacturing cost is reduced, Which is eco-friendly and does not require a separate adhesive layer mediating between the insulating layer 200 and the electrode 300 in order to bond the insulating layer 200 and the electrode 300 to the printed circuit board It is possible to avoid or minimize deterioration of the heat dissipation characteristics and to reduce the thickness of the printed circuit board as a whole.

Further, unlike the conductive ink composition used in the conventional screen printing method, the printed circuit board according to the present invention can effectively prevent / inhibit the oxidation of the conductive metal particles contained therein, and is excellent in sintering at a low temperature of 200 ° C or less By using the conductive ink composition which can secure the electric conductivity and can easily control the thickness of the electrode formed by the appropriate viscosity and the tin value or the like, it is possible to improve the electric conductivity, i.e., the low electric resistance, It is possible to reduce the thickness of the printed circuit board as well as to avoid or minimize the performance degradation such as extension of the life of the printed circuit board due to heat generation and malfunction and furthermore to reduce the thickness of the insulating layer 200 ), Particularly shrinkage, can be avoided / minimized.

3 schematically illustrates embodiments of various cross-sectional structures of a printed circuit board according to the present invention. Specifically, FIG. 3A schematically shows a cross-sectional structure of a metal base printed circuit board, which further includes a via hole 110 in which the metal base substrate 100 improves heat dissipation characteristics. The insulating layer 200 is continuously formed in the via hole 110 so that the insulating layer 200 and the metal base substrate 100 are connected to each other. It is expected that the heat dissipation characteristics will be improved as the contact area increases.

3B schematically shows a cross-sectional structure of a metal core double-sided printed circuit board in which electrodes 300 are formed on both sides of a metal base board 100. As shown in FIG. The metal base substrate 100 may further include an energization hole 120 for energizing between the electrodes 300 formed on both sides and the insulating layer 200 is continuously formed in the energization hole 120 And the electrode 300 is continuously formed thereon.

3C schematically shows a cross-sectional structure of a metal base printed circuit board in which an insulating layer 200 is partially formed according to a circuit pattern in which the electrode 300 is formed. A method for partially forming the insulating layer 200 according to a circuit pattern is not particularly limited. However, in order to suppress the material waste of the insulating composition constituting the insulating layer 200, A method of forming the insulating layer 200 according to a circuit pattern by a screen printing method is more preferable than a method of coating or laminating on a substrate 100 in a predetermined size.

Furthermore, since the material constituting the insulating layer 200 generally has a thermal expansion coefficient ten times or more larger than that of the material constituting the metal base board 100, the insulating layer 200 is formed between the insulating layers 200 The separation between the insulating layer 200 and the metal base substrate 100 can be avoided / minimized through securing space.

FIG. 3D schematically shows a cross-sectional structure of a metal-based multilayer printed circuit board in which two or more electrode layers are formed on the metal base substrate 100. An insulating layer 200 and a first electrode 310 are sequentially formed on the metal base substrate 100 and an adhesive layer 400 and a second electrode 320 are sequentially formed thereon, . The adhesive layer 400 may be made of a prepreg, an epoxy resin, or the like.

[Example]

1. Manufacturing Example

The insulating compositions and conductive ink compositions of the examples and comparative examples were respectively prepared by the components and mixing ratios shown in Table 1 below. Specifically, the insulating composition was prepared by mixing the following components in the following mixing ratios and then stirring the mixture for 1 hour using a 3-roll mill. The conductive ink composition was prepared by mixing the following components in the following proportions Dispersed for about 30 minutes using a post-disperser (manufacturer: Nanointec; product name: PD mixer), and the linearly dispersed ink composition was dispersed in a three-roll mill (manufacturer: Inoue; , Stirring for 30 minutes to be highly dispersed, and finally, filtering to remove impurities. In Table 1 below, the compounding ratio of the components is% by weight for the insulating composition, and is by weight for the conductive ink composition.

Constituent Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2
Insulating composition Polymer resin 7 7 30 25 7 6 Inorganic particles 1 84 83 25 40 86 88 Inorganic Particles 2 2 3 15 10 Hardener 7 7 30 25 7 6


Conductive ink
Composition Metal particles 1 75 83 83 83 100 90 Metal particles 2 25 17 17 17 - 10 Metal particles 3 - - 5 10 - - Binder 1 One One One One One One Binder 2 3 3 3 3 3 3 Binder 3 2 2 2 2 2 2 Solvent 1 5 5 5 5 5 5 Solvent 2 4 4 4 4 6 6

- Polymer resin: Epoxy resin (Manufacturer: Kukdo Chemical Co., Ltd .: KDS8161)

- Inorganic particles 1: Magnesium oxide (manufactured by Ube Material Industries; product name: RF-10cs-sc)

- Inorganic Particles 2: Alumina Fiber (Manufacturer: Nanotechnology)

- Hardener (Manufacturer: Kukdo Chemical Co., Ltd .; Product name: dyhard 100sf)

- Metal Particle 1: A micro-sized plate was prepared from (Ag) particles (manufacturer: Nippon Kokusan Co., Ltd., product name: N300)

- metal particles 2: silver (Ag) neodecanoate (manufacturer: LS wire; complex type silver (Ag) particles)

- Metal particles 3: Nano silver particles (Manufacturer: LS Cable)

- Binder 1: Ethylcellulose

- Binder 2: Polyester (Manufacturer: Bedchem; Product name: AD302)

- Binder 3: Polymethyl methacrylate

2. Evaluation methods and results

Each of the insulating compositions and the conductive ink compositions of the examples and comparative examples was screen-printed on an aluminum base substrate (applied, followed by baking at 200 캜 for 30 minutes in an air atmosphere baking furnace) to form an insulating layer having a thickness of 100 탆, And the widths thereof were 70 μm and the length was 10 cm. The thermal conductivity of the insulating layer and the line resistance of the electrodes were measured. The results are shown in Table 2 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Thermal conductivity (W / mK) 8.1 8.6 9.4 10.3 3.1 3.6 Line resistance (× 10 ^-6 Ω) 7.6 6.7 3.6 2.9 35.7 16.8

As shown in the above Table 2, the insulating layers of Examples 1 to 4 exhibit a very high thermal conductivity of about 8 to 10 W / mK, so that excellent heat dissipation characteristics, On the other hand, the insulation layers of Comparative Examples 1 and 2 are expected to have insufficient heat dissipation properties due to low thermal conductivity of about 3 W / mK, thereby shortening the life of the printed circuit board and deteriorating the performance.

As shown in Table 2, although the conductive ink compositions of Examples 1 to 4 were fired at a low temperature of 200 占 폚, the micro-sized plates included therein had a large specific surface area of the (Ag) particles, (Ag) particles are arranged on the pores between the silver particles and the large contact area between the particles, so that the sintering between the metal particles proceeds well as shown in Fig. 4, It has been confirmed that a low line resistance of less than 10 ^-6 Ω forms an electrode of high electrical conductivity.

On the other hand, the conductive ink composition of Comparative Example 1 in which the complex type silver (Ag) particles are not included and the micro size plate contains only (Ag) particles and the conductive ink composition of Comparative Example 2 in which the complex type silver The conductive ink composition showed that sintering hardly occurs between metal particles when firing at a low temperature of 200 占 폚, thereby forming a low electric conductivity electrode with a high line resistance well exceeding 8 占^10-6 ?.

While the present invention has been described with reference to the preferred embodiments thereof, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. It is therefore to be understood that the modified embodiments are included in the technical scope of the present invention if they basically include elements of the claims of the present invention.

100: metal base substrate 200: insulating layer
300: electrode 400: adhesive layer

Claims (17)

A metal base substrate;
An insulating layer formed on the metal base substrate and made of an insulating composition comprising an insulating polymeric resin and 40 to 90% by weight of high-heat-releasing inorganic particles based on the total weight of the insulating composition; And
And an electrode of a circuit pattern formed on the insulating layer. The method according to claim 1,
The high heat-resistant inorganic particles are hexagonal boron nitride (hBN), cubic boron nitride (cBN), a spherical alumina (Al ₂ O _3), alumina fiber, zinc (ZnO), magnesium oxide (MgO), barium titanate ( BaTiO _3), strontium titanate (SrTiO ₃₎ and titanium dioxide (TiO _2), the metal printed circuit board, comprising a step of including one or more inorganic particles selected from the group consisting of. 3. The method of claim 2,
Wherein the high heat dissipation inorganic particles have an average particle diameter of 0.01 to 20 占 퐉 and have a shape of a spherical shape, a rod shape, a plate shape, or a nano-sheet shape. Board. 4. The method according to any one of claims 1 to 3,
Wherein the insulating composition comprises at least one member selected from the group consisting of potassium titanate whisker having a particle size of 1 nm to 100 탆, aluminum oxide, silicon nitride, silicon carbide, silicon oxide, boron nitride, boron oxide, aluminum nitride, 0.01 to 70 parts by weight of at least one reinforcing material selected from the group consisting of whiskers of alumina, zirconia oxide, titanium oxide, carbon nanotubes, nano-diamonds, industrial sapphire, glass fibers, fine powders of carbon fibers, Wherein the metal printed circuit board comprises: 4. The method according to any one of claims 1 to 3,
Wherein the insulating polymer resin comprises at least one polymer resin selected from the group consisting of an epoxy resin, a polyimide resin, a polyamide imide resin, and a polyester resin. 4. The method according to any one of claims 1 to 3,
Wherein the insulating layer is formed by a screen printing method and has a thickness of 30 to 100 mu m and a thermal conductivity of 8 W / mK or more. 4. The method according to any one of claims 1 to 3,
Wherein the metal base substrate is made of aluminum or an aluminum alloy, a copper or copper alloy, a magnesium or magnesium alloy, a titanium or a titanium alloy, a melted or plated steel sheet thereof, or a silicon or zinc melted or plated steel sheet, Wherein the metal substrate is a metal substrate. 8. The method of claim 7,
Wherein a surface of the metal base substrate on which the insulating layer is formed is physically or chemically surface-treated to improve adhesion to the insulating layer. 4. The method according to any one of claims 1 to 3,
Wherein the electrode comprises conductive metal particles comprising micro-sized silver particles and complexed silver (Ag) particles in a blending ratio of 75:25 to 85:15, and a binder in an amount of from 1.5 to 10 (based on 100 parts by weight of the conductive metal particles) And 5 to 20 parts by weight of an organic solvent, based on the total weight of the conductive ink composition. 10. The method of claim 9,
The micro-sized silver (Ag) particles are in the form of a polygonal plate and have a 50% volume cumulative particle size (D ₅₀ ) of 300 to 500 nm according to a laser diffraction scattering particle size distribution measurement method, a 99% (D ₉₉ ) of 1.5 to 2 탆 and a thickness of 3 to 30 nm. 11. The method of claim 10,
The micro-sized silver (Ag) particles are surface-treated with at least one surface treating agent selected from the group consisting of triazole compounds, saturated fatty acids, unsaturated fatty acids, inorganic metal compound salts, organic metal compound salts, polyaniline resins and metal alkoxides Wherein the metallic printed circuit board is a printed circuit board. 10. The method of claim 9,
The complex-type silver (Ag) particles are prepared by reacting silver precursor with at least one branched chain carboxylic acid selected from the group consisting of neohexanoic acid, neoheptanoic acid, isooctanoic acid, isonicotinic acid, neodecanoic acid and neodecanoic acid ≪ / RTI > 10. The method of claim 9,
Wherein the conductive metal particles further comprise 5 to 10 parts by weight of nano-sized metal particles based on 100 parts by weight of the conductive metal particles. 10. The method of claim 9,
Wherein the binder is a combination of ethyl cellulose, polyester and polymethylmethacrylate, and wherein the organic solvent is a combination of texanol and diethylene glycol monobutyl acetate. 10. The method of claim 9,
Wherein the electrode is formed by a screen printing method and has a thickness of 10 to 30 占 퐉, a print resolution of 60 占 퐉 or more, and a line resistance of 8 占^10-6 ? Or less. 4. The method according to any one of claims 1 to 3,
Wherein the metal base substrate further comprises a via hole in which an insulating layer is continuously formed. 4. The method according to any one of claims 1 to 3,
Wherein the insulating layer is formed according to a circuit pattern in which the electrode is formed.

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