Patent Application
20120073863
This application claims the benefit of Korean Patent Application No. 10-2010-0094511, filed Sep. 29, 2010, entitled “Anodized heat-radiating substrate and method for manufacturing the same”, which is hereby incorporated by reference in its entirety into this application.
1. Technical Field
The present invention relates to an anodized heat-radiating substrate and a method of manufacturing the same.
2. Description of the Related Art
Generally, printed circuit boards (PCBs) are manufactured by patterning one or both sides of a substrate, composed of various thermosetting resins, using copper foil, and disposing and fixing ICs or electronic parts on the substrate to form an electric circuit and then coating the substrate with an insulator. Recently, it has been increasingly required to highly functionalize electronic components with the development of electronics industry, so that printed circuit boards mounting such electronic components have also been required to become dense and thin, with the result that single-layer printed circuit boards are being converted into multi-layer printed circuit boards (MLBs).P
Conventional multi-layer printed circuit boards are advantageous in that they are easily densified and integrated, but are disadvantageous in that they do not effectively cope with the problem of heat radiation accompanying the densification and integration of electronic components.
Meanwhile, nowadays, as electronic components have become light, thin, dense and small, the problem of radiating the heat emitted from an electronic component has been caused. Therefore, recently, research has been done into heat-radiating substrates which can use an anodizing process to maximize the heat radiation effect.
However, such an anodized heat-radiating substrate is advantageous in that it can easily realize high radiation performance, but is disadvantageous in that it cannot be easily converted into a multi-layer heat-radiating substrate. That is, this anodized heat-radiating substrate is problematic in that it is difficult to realize the densification and integration of electronic components.
Accordingly, the present invention has been devised to solve the above-mentioned problems, and the present invention intends to provide an anodized heat-radiating substrate which can maintain radiation characteristics and which can use a connecting member to form a multilayer structure in order to overcome the difficulty of arranging the elements.
An aspect of the present invention provides an anodized heat-radiating substrate, including: an anodized substrate including a metal layer having a through-hole and an anodized oxide layer formed on an entire surface of the metal layer; a first inner circuit layer formed on one side of the anodized substrate and a second inner circuit layer formed on the other side of the anodized substrate; a hole plating layer formed on the inner wall of the through-hole; a first insulation layer formed on one side of the anodized substrate and a second insulation layer formed on the other side of the anodized substrate; a first outer circuit layer formed on the first insulation layer and a second outer circuit layer formed on the second insulation layer; and a connecting member disposed in the through-hole to electrically connect the first outer circuit layer with the second outer circuit layer.
The anodized heat-radiating substrate may further include: a plugging ink layer embedded in the through-hole and protruding outside the first inner circuit layer and the second inner circuit layer which are electrically connected to each other by the hole plating layer.
Here, the connecting member may be disposed in the plugging ink layer to electrically connect the first outer circuit layer with the second outer circuit layer.
Further, the metal layer may be made of aluminum, and the anodized oxide layer may be made of alumina.
Further, the connecting member may include an aluminum wire and an alumina layer surrounding the aluminum wire.
Another aspect of the present invention provides a method of manufacturing an anodized heat-radiating substrate, including: forming a through-hole in a metal layer and then forming an anodized oxide layer on an entire surface of the metal layer over to provide an anodized substrate; forming a plating layer on an inner wall of the through-hole and both sides of the anodized oxide layer and then patterning the plating layer to form a first inner circuit layer and a second inner circuit layer such that the first inner circuit layer is electrically connected to the second inner circuit layer by the hole plating layer formed on the inner wall of the through-hole; inserting a connecting member into the through-hole; forming a first insulation layer on one side of the anodized substrate and forming a second insulation layer on the other side of the anodized substrate; and forming a first outer circuit layer on the first insulation layer and forming a second outer circuit layer on the second insulation layer such that the first outer circuit layer is electrically connected with the second outer circuit layer by the connecting member.
Here, the method may further include, between the forming of the first and second inner circuit layers and the inserting of the connecting member: forming a plugging ink layer in the through-hole such that the plugging ink layer protrudes outside the first inner circuit layer and the second inner circuit layer connected by the hole plating layer.
Further, the method may further include, between the forming of the first and second insulation layers and the forming of the first and second outer circuit layers: grinding exposed portions of the first insulation layer and the second insulation layer such that protrusions of both ends of the connecting member are cut.
Further, the inserting of the connecting member into the through-hole may include: inserting the connecting member into the plugging ink layer.
Meanwhile, the metal layer may be made of aluminum, and the anodized oxide layer may be made of alumina.
Further, the connecting member may include an aluminum wire and an alumina layer surrounding the aluminum wire, and, in the grinding of the exposed portions of the first insulation layer and the second insulation layer, the protrusions of both ends of the connecting member may be cut, thereby making the aluminum wire of the connecting member exposed.
Various objects, advantages and features of the invention will become apparent from the following description of embodiments with reference to the accompanying drawings.
The terms and words used in the present specification and claims should not be interpreted as being limited to typical meanings or dictionary definitions, but should be interpreted as having meanings and concepts relevant to the technical scope of the present invention based on the rule according to which an inventor can appropriately define the concept of the term to describe the best method he or she knows for carrying out the invention.
The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
The objects, features and advantages of the present invention will be more clearly understood from the following detailed description of preferred embodiments taken in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant descriptions thereof are omitted. Further, in the following description, the terms “first”, “second”, “one side”, “the other side” and the like are used to differentiate a certain component from other components, but the configuration of such components should not be construed to be limited by the terms. Further, in the description of the present invention, when it is determined that the detailed description of the related art would obscure the gist of the present invention, the description thereof will be omitted.
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.
Structure of Anodized Heat-Radiating Substrate
As shown in
The anodized heat-radiating substrate may further include a plugging ink layer 60 embedded in the through-hole 5 and protruding outside the first inner circuit layer 30 and the second inner circuit layer 40 which are electrically connected by the hole plating layer 50.
The anodized substrate 11, which serves to effectively discharge the heat generated from the inside of the anodized heat-radiating substrate to the atmosphere, includes a metal layer 10 and an anodized oxide layer 20.
Here, the metal layer 10 may be made of aluminum, but the present invention is not limited thereto. The metal layer may also be made of manganese (Mg), zinc (Zn), titanium (Ti), hafnium (Hf) or the like, as long as it is a metal that can be anodized by an anodizing process.
The anodized oxide layer 20 is an insulation layer formed by chemically reacting the metal layer 10 with oxygen by an anodizing process. When the metal layer 10 is made of aluminum, the anodized oxide layer 20 becomes an alumina layer. Since an alumina layer has high thermal conductivity compared to other insulating members, the metal layer 10 can easily radiate heat even though the alumina layer is formed on the entire surface of the metal layer 10.
The first inner circuit layer 30 is formed on one side of the anodized substrate 11, and the second inner circuit layer 40 is formed on the other side of the anodized substrate 11. Further, the first inner circuit layer 30 and the second inner circuit layer 40 are electrically connected by the hole plating layer 50 (which is designated in order to be distinguished from other plating layers) formed on the inner wall of the through-hole 5.
The plugging ink layer 60 is made of an insulating material, is embedded in the through-hole 5, and protrudes outside the first inner circuit layer 30 and the second inner circuit layer 40 which are electrically connected by the hole plating layer 50. The plugging ink layer 60 serves to prevent a gap from occurring in the through-hole 5 and to prevent the hole plating layer 50 formed on the inner wall of the through-hole 5 from being oxidized. Particularly, in the anodized heat-radiating substrate according to an embodiment of the present invention, the plugging ink layer 60 serves to completely prevent a gap from forming between the edge of the through-hole 5 and the connecting member 130.
However, when the diameter of the section of the connecting member 130 is equal to the diameter of the inner side of the hole plating layer 50, the plugging ink layer 60, shown in
The first insulation layer 90 is formed on one side of the anodized substrate 11, and the second insulation layer 100 is formed on the other side of the anodized substrate 11. The first insulation layer 90 serves to electrically insulate the first inner circuit layer 30 from the first outer circuit layer 110 such that a short does not occur therebetween, and the second insulation layer 100 serves to electrically insulate the second inner circuit layer 40 from the second outer circuit layer 120 such that a short does not occur therebetween. Here, the first insulation layer 90 or the second insulation layer 100 may be made of a composite polymer resin, such as prepreg or the like, or an epoxy resin, such as FR-4, BT or the like.
The first outer circuit layer 110 is formed on the first insulation layer 90, and the second outer circuit layer 120 is formed on the second insulation layer 100. These first and second outer circuit layers 110 and 120 are electrically connected with each other by the connecting member 130.
The connecting member 130 is inserted in the through-hole 5 or the plugging ink layer 60 formed in the through-hole 5 to electrically connect the first outer circuit layer 110 with the second outer circuit layer 120. Therefore, the connecting member must be made of a conductive material.
Further, the lower surface of the first outer circuit layer 110 is brought into contact with the upper surface of the second outer circuit layer 120 by the connecting member.
Further, the diameter of the section of the connecting member 130 must be equal to or smaller than the diameter of the inner side of the hole plating layer 50 formed on the inner wall of the through-hole 5.
That is, in the anodized heat-radiating substrate according to an embodiment of the present invention, the first inner circuit layer 30 and the second inner circuit layer 40 are electrically connected by the hole plating layer 50, and the first outer circuit layer 110 and the second outer circuit layer 120 are electrically connected by the connecting member 130. However, the first outer circuit layer 110 and the first inner circuit layer 30 and the second outer circuit layer 120 and the second inner circuit layer 40 can also be connected with other by forming a via hole and then plating the via hole with metal. It is obvious that such configurations belong to the scope of the present invention.
Method of Manufacturing an Anodized Heat-Radiating Substrate
First, as shown in
The anodizing is used to form an anodized film by oxidizing the surface of a material to be treated (for example, aluminum or an aluminum alloy) using the material to be treated as an anode in an electrolyte such as sulfuric acid, oxalic acid or the like. Concretely, if the metal layer 10 is made of aluminum, the surface of the metal layer 10 reacts with the electrolyte solution to form aluminum ions (Al3+) at the interface therebetween, and the current density of the surface of the metal layer 10 is increased by the voltage applied to the metal layer 10 to locally generate heat. The heat thus generated causes a larger amount of aluminum ions to be formed. As a result, a plurality of pits are formed in the surface of the metal layer 10, and oxygen ions move to the pits and then react with aluminum ions, thereby forming an alumina layer. Since the alumina layer has high thermal conductivity compared to other insulating members, the anodized substrate 11 can easily radiate heat even though the alumina layer is formed on the entire surface of the metal layer 10.
In this case, the metal layer 10 may be made of aluminum, but the present invention is not limited thereto. The metal layer 10 may also be made of manganese (Mg), zinc (Zn), titanium (Ti), hafnium (Hf) or the like, as long as it is a metal that can be anodized by an anodizing process.
Subsequently, as shown in
The process of forming the inner circuit layers 30 and 40 is described as follows. Concretely, a dry film is applied onto the plating layer formed on one side or both sides of the anodized substrate 11, and is then irradiated with ultraviolet (UV) with it blocked by a mask. Thereafter, when a developer is applied to the dry film, the portion of the dry film which was cured by the ultraviolet irradiation is left over, whereas the other portion of the dry film which was not cured by the ultraviolet irradiation is removed, thus forming an etching resist pattern 35 (refer to
Meanwhile, the first inner circuit layer 30 is connected to the second inner circuit layer 40 by the hole plating layer 50.
Subsequently, as shown in
The following is a detailed description of the process of forming the plugging ink layer 60. First, a mask having a hole corresponding to the through-hole 5 is disposed on the anodized oxide layer 11. Subsequently, plugging ink is applied onto the mask, and is then pushed to the mask hole by a squeegee, so that the plugging ink is charged in the through-hole 5 through the mask hole.
In this case, the plugging ink includes an insulating material, and is charged in the through-hole 5 to prevent a gap from forming in the through-hole 5 and to prevent the hole plating layer 50 formed on the inner wall of the through-hole 5 from being oxidized. Particularly, in the process of manufacturing the anodized heat-radiating substrate according to this embodiment, the plugging ink serves to completely prevent a gap from forming between the edge of the through-hole 5 and the connecting member 130 during a series of procedures of charging the plugging ink in the through-hole 5 and then inserting a connecting member 130 (refer to
After the connecting layer 130 is inserted into the plugging ink, the plugging ink is cured to form the plugging ink layer 60.
However, since the plugging ink layer 60 is formed in order to fill the gap between the through-hole 5 and the connecting member 130, when the diameter of the section of the connecting member 130 is accurately equal to the diameter of the inner side of the hole plating layer 50 formed on the inner wall of the through-hole 5, the process of forming the plugging ink layer 60 may be omitted.
Subsequently, as shown in
First, the connecting member 130 is provided (refer to
First, the connecting member 130 must include a conductive material because it is used to electrically connect the first outer circuit layer 110 with the second outer circuit layer 120.
Further, the length of the connecting member 130 must be equal to or larger than the length of the plugging ink layer 60 because the lower surface of the first outer circuit layer 110 is brought into contact with the upper surface of the second outer circuit layer 120 such that the first outer circuit layer 110 is electrically connected with the second outer circuit layer 120.
Further, the diameter of the section of the connecting member 130 must be equal to or smaller than the diameter of the inner side of the hole plating layer 50 formed on the inner wall of the through-hole 5. In this case, when the diameter of the section of the connecting member 130 is equal to the diameter of the inner side of the hole plating layer 50, the plugging ink layer 60, shown in
Here, the connecting member 130 includes an aluminum wire 70 and an alumina layer 75 formed on the entire surface of the aluminum wire 70 (refer to
Subsequently, as shown in
Subsequently, as shown in
Here, a mechanical grinding process may be used to grind the first and second insulation layers 90 and 100.
A jet scrub grinding process, a buff grinding process or a ceramic grinding process may be used as the mechanical grinding process. Here, the jet scrub grinding process is a process of grinding the surface of an insulation layer by blowing out alumina (Al2O3) particles using high pressure, the buff grinding process is a process of grinding an insulation layer using the pressure generated by rotating buffs at high speed, and the ceramic grinding process is a process of grinding an insulation layer by rotating ceramic balls at ultrahigh speed.
Subsequently, as shown in
As described above, the anodized heat-radiating substrate according to the present invention is advantageous in that it can maintain radiation characteristics because an anodized oxide layer is formed on the entire surface of a metal layer.
Further, the anodized heat-radiating substrate according to the present invention is advantageous in that it can be used in the form of a high-density/highly-integrated multilayer substrate because outer circuit layers are electrically connected with each other by a connecting member inserted in a through-hole and inner circuit layers as well are electrically connected with each other.
Further, according to the anodized heat-radiating substrate according to the present invention, the connecting member serves to further improve radiation characteristics as well as to electrically connect outer circuit layers (the first outer circuit layer and the second outer circuit layer).
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.
Simple modifications, additions and substitutions of the present invention belong to the scope of the present invention, and the specific scope of the present invention will be clearly defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2010-0094511 | Sep 2010 | KR | national |
