HEAT DISSIPATING SUBSTRATE AND METHOD OF MANUFACTURING THE SAME

Abstract

Disclosed herein are a heat dissipating substrate and a method of manufacturing the same. The heat dissipating substrate includes: a substrate that is formed of a metal material, wherein at least one via hole is formed in the substrate; an insulating layer formed on a surface of the substrate; a coating layer that is formed on an inner wall surface of the via hole and is formed of a conductive or non-conductive material; a plurality of metal patterns that are formed on the insulating layer and are electrically separated from one another; a metal layer that is extended from the metal patterns to be formed on the coating layer formed on the inner wall surface of the via hole; and a filling material that is formed of a non-conductive material and is filled between the metal layers in the via hole.

Description

CROSS REFERENCE(S) TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. Section 119 of Korean Patent Application Serial No. 10-2011-0139245, entitled “Heat Dissipating Substrate and Method of Manufacturing the Same” filed on Dec. 21, 2011, which is hereby incorporated by reference in its entirety into this application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a heat dissipating substrate and a method of manufacturing the same, and more particularly, to a heat dissipating substrate formed of a metal, wherein a surface of the heat dissipating substrate is anodized, and an inner wall surface of a via of the heat dissipating substrate is plugged using a conductive or non-conductive material, and a method of manufacturing the heat dissipating substrate.

2. Description of the Related Art

In general, various light emitting units such as a light emitting diode (LED) are mounted on a substrate, and when they are driven as a light-emitting body, heat is generated due to light emission, and the heat needs to be effectively dissipated to increase the lifespan and efficiency of the light emitting units.

In particular a LED has low power consumption and high luminance, and thus is widely used as a light source for homes and industrial purposes.

Recently, a LED is used as a light source of illuminating apparatuses and backlights for liquid crystal displays (LCD). The LED is supplied in a package which is easily mounted in various devices such as illuminating apparatuses.

A LED package has a structure in which the LED package is mounted on a substrate and a LED is encapsulated by using a molding material. Here, not only are the functions of the LED package of protecting the LED and providing a connection to a light emitting device important, but heat dissipation performance of the LED package for dissipating heat from the LED is also an important evaluation standard for evaluating LED packages.

Since a contact surface of a LED with a substrate is the largest, and heat may preferably be dissipated through the substrate, and various heat dissipation structures for dissipating heat through a substrate are being developed.

The most effective way of dissipating heat of a light emitting unit is to include a metal substrate so that heat generated in the light emitting unit is dissipated through the metal substrate to the outside, and accordingly, various researches are being conducted into a heat dissipating substrate which may increase performance and lifetime of a LED, by simplifying a structure of the heat dissipating substrate and improving heat dissipation performance thereof.

RELATED ART DOCUMENT

Patent Document

(Patent Document 1) Korean Patent Laid-Open Publication No. 2010-016737

SUMMARY OF THE INVENTION

An object of the present invention is to provide a heat dissipating substrate in which an inner wall surface of a via formed in a metal substrate is plugged using a conductive or non-conductive material so as to fill an inner portion of the via using the non-conductive material, thereby reducing a size of the via hole, and a method of manufacturing the same.

According to an exemplary embodiment of the present invention, there is provided a heat dissipating substrate, comprising: a substrate that is formed of a metal material, wherein at least one via hole is formed in the substrate; an insulating layer formed on a surface of the substrate; a coating layer that is formed on an inner wall surface of the via hole and is formed of a conductive or non-conductive material; a plurality of metal patterns that are formed on the insulating layer and are electrically separated from one another; a metal layer that is extended from the metal patterns to be formed on the coating layer formed on the inner wall surface of the via hole; and a filling material that is formed of a non-conductive material and is filed between the metal layers in the via hole.

The substrate may be formed of a metal having an excellent thermal conductivity, and be formed of aluminum (Al).

The insulating layer formed on the surface of the substrate may be formed of an oxide coating layer (Al₂O₃) by anodizing.

The via hole may be formed by using a mechanical method such as drilling or punching or a chemical method such as etching.

According to another exemplary embodiment of the present invention, there is provided a method of manufacturing a heat dissipating substrate, the method comprising: preparing a metal substrate and forming at least one via hole that passes through the metal substrate; forming an insulating layer on a surface of the metal substrate including the via hole; forming a coating layer using a non-conductive material on an inner wall surface of the via hole, on which the insulating layer is formed; forming a metal layer on the coating layer formed on the inner wall surface of the via hole and the insulating layer formed on the surface of the metal substrate; forming a plurality of metal patterns by patterning the metal layer formed on the insulating layer formed on the surface of the metal substrate; and injecting a filling material formed of a non-conductive material between coating layers formed on the inner wall surface of the via hole.

In the forming of the insulating layer on a surface of the metal substrate, the insulating layer may be formed of an oxide coating layer by anodizing.

The forming of the coating layer on an inner wall surface of the via hole may include: filling a non-conductive material in the via hole through a plugging process; and forming a through hole in the non-conductive material filled in the via hole.

The non-conductive material filled in the via hole may be epoxy or polymer, and the through hole may be formed by drilling or laser processing.

According to another exemplary embodiment of the present invention, there is provided a method of manufacturing a heat dissipating substrate, the method comprising: preparing a metal substrate and forming at least one via hole that passes through the metal substrate; forming an insulating layer on a surface of the metal substrate including the via hole; forming a coating layer formed of a conductive material on an inner wall surface of the via hole, on which the insulating layer is formed; forming a metal layer on the coating layer formed on the inner wall surface of the via hole and the insulating layer formed on the surface of the metal substrate; forming a plurality of metal patterns by patterning the metal layer formed on the insulating layer formed on the surface of the metal substrate; and injecting a filling material formed of a non-conductive material between the coating layers formed on the inner wall surface of the via hole.

The forming of the coating layer on an inner wall surface of the via hole may include: fill plating an inner portion of the via hole using a conductive material through a plating process; and forming a through hole in the fill-plated conductive material formed in the via hole.

In the forming of the coating layer on an inner wall surface of the via hole, the coating layer may be formed as a seed layer only on the inner wall surface of the via hole by using a conductive material and a plating process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a heat dissipating substrate according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a heat dissipating substrate according to an embodiment of the present invention, on which a light emitting unit is mounted;

FIGS. 3A through 3H are schematic views illustrating a method of manufacturing a heat dissipating substrate according to an embodiment of the present invention; and

FIGS. 4A through 4G are schematic views illustrating a method of manufacturing a heat dissipating substrate according to another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the technical configuration of the light emitting diode package according to the present invention and the effects thereof will be clearly understood from the detailed description below with reference to the accompanying drawings in which exemplary embodiments of the present invention are shown.

First, FIG. 1 is a cross-sectional view illustrating a heat dissipating substrate 100 according to an embodiment of the present invention.

As illustrated in FIG. 1, the heat dissipating substrate 100 may include a substrate 110 formed of a metal material, an insulating layer 120 formed on a surface of the substrate 110, a coating layer 130 formed on an inner wall surface of a via hole 111 formed in the substrate 110, a metal pattern 150 formed on the insulating layer 120 formed on the surface of the substrate 110, a metal layer 140 formed on the coating layer 130, and a filling material 160 filled in inner portions of the metal layer 140.

The substrate 110 may be formed of a metal such as an aluminum (Al) which is a representative metal having excellent thermal conductivity, and at least one via hole 111 may be formed on the substrate 110.

The via hole 111 may be formed by CNC drilling or etching. Also, the via hole 111 may be used as an electrical connection portion that electrically connects metal patterns 150 formed on upper and lower surfaces of the substrate 110 which will be described below.

The insulating layer 120 may be formed on the entire surface of the substrate 110 including the inner wall surface of the via hole 111. The insulating layer 120 may be formed on the substrate 110, which is formed of aluminum, using an oxide coating layer (Al₂O₃) by anodizing. The anodizing may be performed by using an organic acid, a sulfuric acid, or a mixture thereof.

Aluminum used to form the substrate 110 is a metal which is easily obtainable at relatively low price, and has excellent thermal conductivity, and an oxide coating layer formed on a surface of the substrate 110 may also be formed using a thin insulator that has a relatively high thermal conductivity of about 10 to 30 W/mK by anodizing, thereby providing low thermal resistance.

Accordingly, compared to copper or ceramics which is used to form a substrate according to the related art, not only has the substrate 110 formed of aluminum excellent heat dissipation performance but also the substrate 110 may be anodized relatively easily, and thus the costs and time for processing may be reduced.

The coating layer 130 is formed on the inner wall surface of the via hole 111, and the coating layer 130 may be formed of a conductive material such as a metal or a non-conductive material such as epoxy or polymer.

When the coating layer 130 is formed of a conductive material, the coating layer 130 may be formed by plating, and when the coating layer 130 is formed of a non-conductive material, the via hole 111 may be filled with a non-conductive material so as to completely fill the via hole 111, and then a through hole is formed by drilling or laser processing so that the coating layer 130 is formed only on the inner wall surface of the via hole 111.

Also, the metal patterns 150 are electrically separated from adjacent metal patterns on the insulating layer 120, and a portion on the metal patterns 150 where a light emitting unit such as a LED is to be mounted may be formed as an electrode portion. The metal patterns 150 may be extended inwardly into the via hole 111 and be formed as the metal layer 140 on the coating layer 130. The metal patterns 150 may perform the function as an electrode and the function of heat dissipation at the same time.

The metal patterns 150 may be formed on the insulating layer 120 as illustrated in FIG. 1, or alternatively, a portion of the insulating layer 120 may be removed and the metal patterns 150 may be formed on an exposed portion of an upper surface of the substrate 110. In this case, a lower surface of the metal pattern 150 directly contacts the upper surface of the substrate 110, and a LED is mounted on an upper surface of the metal pattern 150, thereby further enhancing the effects of heat dissipation of the LED.

As described above, the insulating layer 120, the coating layer 130, and the metal layer 140 extended from the metal patterns 150 may be sequentially formed in the via hole ill, and a through hole is formed between portions of the metal layer 140 so as to fill a filling material 160 in the through hole. The filling material 160 may be epoxy or polymer formed of a non-conductive material, and the metal layer 140 formed on inner portions of the via hole 111 is shorted by the filling material 160 to thereby prevent a short circuit between the metal patterns 150.

Also, as described in the objective of the present invention, as the insulating layer 120, the coating layer 130, and the metal layer 140 are sequentially formed in the via hole 111 which is formed to have a relatively large size by drilling or punching due to characteristics of the metal substrate 110, a diameter of the via hole 111 may be reduced, and the filling material 160 may be injected into the reduced via hole 111.

Consequently, when heat is dissipated through the substrate 110 which is formed of a metal material, due to the characteristics of a metal substrate, the via hole 111 is constricted or expanded by the heat, and here, by reducing the diameter of the via hole 111 by using the coating layer 130 formed on the inner wall surface of the via hole 111, variation in the diameter of the via hole 111 due to thermal deformation of the substrate 110 may be minimized.

Various types of light emitting units may be mounted on a heat dissipating substrate having the above-described structure according to the present invention, and a structure in which a LED is mounted as a light emitting unit will be briefly described as an example below.

FIG. 2 is a cross-sectional view of a heat dissipating substrate according to an embodiment of the present invention, on which a light emitting unit is mounted.

At least one via hole 111 is formed so that a light emitting unit 200, for example, a LED (hereinafter referred to as a LED chip 200) may be mounted on a substrate 110 which is formed of a metal material and on upper and lower surfaces of which metal patterns 150 are formed.

The LED chip 200 is a LED chip having a vertical electrode structure, and one electrode (not shown) formed on the LED chip 200 is directly connected to the metal patterns 150, and the other electrode (not shown) may be electrically connected to the metal patterns 150, on which the LED chip 200 is not mounted, via a wire 210. Here, the metal patterns 150 connected to the LED chip 200 via the wire 210 may be extended up to the lower surface of the metal substrate 110 via the metal layer 140 that is extended to an inner portion of the via hole 111.

Also, a molding unit 220 that covers the LED chip 200 and the wire 210 may be formed on the substrate 110. The molding unit 220 may be formed to a desired form by using a silicon resin, an epoxy resin, or an epoxy molding compound (EMC) or the like and by using a method using an injection molding method, a transfer molding method, or a pin gate molding method.

Hereinafter, a method of manufacturing the heat dissipating substrate having the above-described structure will be described.

FIGS. 3A through 3H are schematic views illustrating a method of manufacturing a heat dissipating substrate according to an embodiment of the present invention.

As illustrated in the drawings, first, a metal substrate 110 is prepared as illustrated in FIG. 3A. The metal substrate 110 may be preferably an aluminum substrate that is gone through a washing operation in which pollutants such as organic materials on a surface thereof are washed off.

The metal substrate 110 may typically have a square shape, or other various forms such as a rectangular or a circular shape according to a processed aluminum substrate. In addition, a thickness of the metal substrate 110 may preferably be about 0.1 mm or greater in consideration of process reliability.

Next, as illustrated in FIG. 3B, at least one via hole 111 that passes through the metal substrate 110 is formed. The via hole 111 may be formed by drilling, punching, or etching.

Also, an insulating layer 120 may be formed on a surface of the metal substrate 110 including the via hole 111 by anodizing.

Next, a coating layer 130 formed of a non-conductive material may be formed on an inner wall surface of the via hole 111, on which the insulating layer 120 is formed. The coating layer 130 may be formed by filling a resin material such as epoxy or polymer which is a non-conductive material, in the via hole 111 on which the insulating layer 120 is formed, and by forming a through hole 131 that passes through a center portion of the non-conductive material filled in the via hole 111, as illustrated in FIG. 3E. Here, the through hole 131 may be formed by drilling or laser processing.

Next, as illustrated in FIG. 3F, a metal layer 140 may be formed on the insulating layer 120 of the metal substrate 110 that includes the coating layer 130 formed on the inner wall surface of the via hole 111. The metal layer 140 may be formed by using a method such as electroplating, electroless plating, or metal deposition.

While the metal layer 140 is formed, an inner portion of the via hole 111 may be completely filled with the metal layer 140 or the metal layer 140 may be formed as a thin layer on the coating layer 130 on the inner wall surface of the via hole 111. When the metal layer 140 is completely filled in the inner portion of the via hole 111, a previous process, that is, a process (not shown) of forming a through hole one more time so that the metal layer 140 filled in the via hole 111 is shorted, like a process of forming the through hole 131 in the non-conductive material filled in the via hole 111 may be performed.

As described above, by further forming the coating layer 130 and the metal layer 140 on the inner wall surface of the via hole 111, a size of the via hole 111 may be reduced, and variation in the size of the via hole 111 due to constriction or expansion of the metal substrate 110 due to thermal deformation may be minimized.

Next, as illustrated in FIG. 3G, the filling material 160 is injected into the inner portion of the metal layer 140 in the via hole 111 so as to completely fill the inner portion of the via hole 111. Here, the filling material 160 may be a non-conductive material such as epoxy or polymer.

Finally, as illustrated in FIG. 3H, the metal layer 140 formed on a surface of the insulating layer 120 may be patterned to form a plurality of metal patterns 150 that are formed on the insulating layer 120 formed on upper and lower surfaces of the metal substrate 110 and are electrically separated.

FIGS. 4A through 4G are schematic views illustrating a method of manufacturing a heat dissipating substrate according to another embodiment of the present invention.

As illustrated in the drawings, first, a metal substrate 110 is prepared as illustrated in FIG. 4A. The metal substrate 110 may be preferably an aluminum substrate that is gone through a washing operation in which pollutants such as organic materials on a surface thereof are washed off.

The metal substrate 110 may typically have a square shape, or other various forms such as a rectangular or circular shape according to a processed aluminum substrate. In addition, a thickness of the metal substrate 110 may preferably be about 0.1 mm or greater in consideration of process reliability.

Next, as illustrated in FIG. 4B, at least one via hole 111 that passes through the metal substrate 110 is formed. The via hole 111 may be formed by drilling, punching, or etching.

Also, as illustrated in FIG. 4C, an insulating layer 120 may be formed on a surface of the metal substrate 110 including the via hole 111 by anodizing.

Next, as illustrated in FIG. 4D, a coating layer 130 formed of a conductive material may be formed on an inner wall surface of the via hole 111 on which the insulating layer 120 is formed. The coating layer 130 may be formed in the via hole 111 on which the insulating layer 120 by using a plating process, and in detail, as a seed layer on the insulating layer 120 on the inner wall surface of the via hole 111 by electroplating or electroless plating.

Also, the coating layer 130 may be formed only on the inner wall surface of the via hole 111 by fill-plating an inner portion of the via hole 111 with a conductive material by plating, and then by forming a through hole 131 in the conductive material filled in the via hole 111. The through hole 131 may be formed by drilling or etching.

Next, as illustrated in FIG. 4E, a metal layer 140 may be formed on the insulating layer 120 of the metal substrate 110 that includes the coating layer 130 formed on the inner wall surface of the via hole 111. The metal layer 140 may be formed by electroplating, electroless plating, or metal deposition.

Here, while the metal layer 140 is formed, the inner portion of the via hole 111 may be completely filled with the metal layer 140 or the metal layer 140 may be formed as a thin layer on the coating layer 130 on the inner wall surface of the via hole 111. When the metal layer 140 is completely filled in the inner portion of the via hole 111, a previous process, that is, a process of forming a through hole one more time so that the metal layer 140 filled in the via hole 111 is shorted, like a process of forming the through hole 131 in the non-conductive material filled in the via hole 111 may be performed.

As described above, by further forming the coating layer 130 and the metal layer 140 on the inner wall surface of the via hole 111, a size of the via hole 111 may be reduced, and variation in the size of the via hole 111 due to constriction or expansion of the metal substrate 110 due to thermal deformation may be minimized.

Next, as illustrated in FIG. 4F, the filling material 160 is injected into the inner portion of the metal layer 140 in the via hole 111 so as to completely fill the inner portion of the via hole 111. Here, a filling material 160 may be a non-conductive material such as epoxy or polymer.

Finally, as illustrated in FIG. 4G, the metal layer 140 formed on a surface of the insulating layer 120 may be patterned to form a plurality of metal patterns 150 that are formed on the insulating layer 120 on upper and lower surfaces of the metal substrate 110 and are electrically separated.

As described above, according to the heat dissipating substrate and the method of manufacturing the heat dissipating substrate according to the embodiments of the present invention, heat generated in a light emitting member mounted on the upper surface of the metal substrate may be efficiently dissipated through the metal substrate.

In addition, a coating layer formed of a conductive or non-conductive material is formed on an inner wall surface of a via hole, and space inside the coating layer is filled, thereby reducing a size of a via. Accordingly, variation in a diameter of the via hole due to thermal deformation of a metal substrate according to contraction or expansion of a metal material may be minimized.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Accordingly, such modifications, additions and substitutions should also be understood to fall within the scope of the present invention.

Claims

1. A heat dissipating substrate, comprising:

a substrate that is formed of a metal material, wherein at least one via hole is formed in the substrate;

an insulating layer formed on a surface of the substrate;

a coating layer that is formed on an inner wall surface of the via hole and is formed of a conductive or non-conductive material;

a plurality of metal patterns that are formed on the insulating layer and are electrically separated from one another;

a metal layer that is extended from the metal patterns to be formed on the coating layer formed on the inner wall surface of the via hole; and

a filling material that is formed of a non-conductive material and is filled between the metal layers in the via hole.

2. The heat dissipating substrate according to claim 1, wherein the substrate is formed of a metal having an excellent thermal conductivity and is formed of aluminum (Al).

3. The heat dissipating substrate according to claim 1, wherein the insulating layer formed on the surface of the substrate is formed of an oxide coating layer (Al2O3) by anodizing.

4. The heat dissipating substrate according to claim 1, wherein the via hole is formed by using a mechanical method such as drilling or punching or a chemical method such as etching.

5. The heat dissipating substrate according to claim 1, wherein the metal patterns are formed on portions of an upper surface of the substrate that are exposed by removing a portion of the insulating layer.

6. The heat dissipating substrate according to claim 1, wherein the filling material is formed of a non-conductive material such as epoxy or polymer.

7. A method of manufacturing a heat dissipating substrate, the method comprising:

preparing a metal substrate and forming at least one via hole that passes through the metal substrate;

forming an insulating layer on a surface of the metal substrate including the via hole;

forming a coating layer using a non-conductive material on an inner wall surface of the via hole, on which the insulating layer is formed;

forming a metal layer on the coating layer formed on the inner wall surface of the via hole and the insulating layer formed on the surface of the metal substrate;

forming a plurality of metal patterns by patterning the metal layer formed on the insulating layer formed on the surface of the metal substrate; and

injecting a filling material formed of a non-conductive material between coating layers formed on the inner wall surface of the via hole.

8. The method according to claim 7, wherein in the forming of the insulating layer on a surface of the metal substrate, the insulating layer is formed of an oxide coating layer by anodizing.

9. The method according to claim 7, wherein the forming of the coating layer on an inner wall surface of the via hole includes:

filling a non-conductive material in the via hole through a plugging process; and

forming a through hole in the non-conductive material filled in the via hole.

10. The method according to claim 1, wherein the non-conductive material filled in the via hole is epoxy or polymer, and the through hole is formed by drilling or laser processing.

11. A method of manufacturing a heat dissipating substrate, the method comprising:

preparing a metal substrate and forming at least one via hole that passes through the metal substrate;

forming an insulating layer on a surface of the metal substrate including the via hole;

forming a coating layer formed of a conductive material on an inner wall surface of the via hole, on which the insulating layer is formed;

forming a metal layer on the coating layer formed on the inner wall surface of the via hole and the insulating layer formed on the surface of the metal substrate;

forming a plurality of metal patterns by patterning the metal layer formed on the insulating layer formed on the surface of the metal substrate; and

injecting a filling material formed of a non-conductive material between the coating layers formed on the inner wall surface of the via hole.

12. The method according to claim 11, wherein the forming of the coating layer on an inner wall surface of the via hole includes:

fill plating an inner portion of the via hole using a conductive material through a plating process; and

forming a through hole in the fill-plated conductive material formed in the via hole.

13. The method according to claim 11, wherein in the forming of the coating layer on an inner wall surface of the via hole, the conductive material is formed, as a seed layer, only on the inner wall surface of the via hole through a plating process.