Patent Application
20110031608
This application claims the benefit of Korean Patent Application No. 10-2009-0072440, filed Aug. 6, 2009, entitled “Power device package and fabricating method of the same”, which is hereby incorporated by reference in its entirety into this application.
1. Technical Field
The present invention relates to a power device package and a method of fabricating the same.
2. Description of the Related Art
A power device, for example, a high-power semiconductor chip selected from among a silicon-controlled rectifier, a power transistor, an insulated gate bipolar transistor, a MOSS transistor, a power rectifier, a power regulator, an inverter, a converter and combinations thereof, is designed to be operated at a voltage of 30˜100 V, or at a voltage above 100 V. Thus, a power device package on which such a high-power semiconductor chip is mounted is required to have high ability to dissipate heat generated from the high power semiconductor chip.
As shown in
The low power device 13 and the high power device 15 are typically connected to the circuit layer using wires (not shown), and this circuit layer is also connected to a lead frame 27 of a housing wires. As such, the elements including the low power device 13 and the high power device 15 are protected from the external environment using molding resin (not shown).
However, the conventional power device package has the following problems.
First, because the high power device 15 is mounted on one surface of the DCB circuit substrate 10 and the heat sink 25 and the copper plate 20 made of metal having high heat conductivity are attached to the other surface of the DCB circuit substrate 10, the DCB circuit substrate 10 having low heat conductivity blocks transfer of heat, undesirably reducing heat dissipation effects.
Second, the copper plate 20 which is expensive is used to improve heat dissipation performance of the DCB circuit substrate 10 having low heat conductivity, undesirably increasing the fabrication cost and the thickness of the power device package.
Third, because the high power device 15 is bonded on the DCB circuit substrate 10 and the DCB circuit substrate 10 is also bonded on the copper plate 20, two bonding procedures should be performed, and as well, heat dissipation performance may be deteriorated at the bonding interface.
Accordingly, the present invention has been made keeping in mind the problems encountered in the related art and the present invention intends to provide a power device package having high heat dissipation performance, and a method of fabricating the same.
Also the present invention intends to provide a power device package which has high heat dissipation performance even without the use of a DCB circuit substrate having low heat conductivity and an expensive copper plate and also which enables reduction of its fabrication cost and thickness, and a method of fabricating the same.
Also the present invention intends to provide a power device package which has a simple configuration thus simplifying a bonding process and reducing the bonding interface that causes deterioration of heat dissipation performance, and a method of fabricating the same.
An aspect of the present invention provides a power device package, including an anodized metal substrate including a metal plate having a cavity formed on one surface thereof and an anodized layer formed on both a surface of the metal plate and an inner wall of the cavity, and a circuit layer formed on the anodized layer; a power device mounted in the cavity of the metal plate so as to be connected to the circuit layer; and a resin sealing material charged in the cavity of the metal plate.
In this aspect, the circuit layer may include an inner circuit layer formed on the inner wall of the cavity, and an outer circuit layer formed on the surface of the metal plate and connected to the inner circuit layer.
Further, a connection member may be formed on the outer circuit layer.
Further, a cover member may be formed on one surface of the metal plate so as to cover the outer circuit layer, and may have a through hole which exposes the outer circuit layer and which has an interconnection portion connected to the outer circuit layer.
Also, a heat sink may be attached to a surface of the anodized metal substrate opposite the surface having the power device.
In this aspect, the metal plate may be made of aluminum or an aluminum alloy, and the anodized layer may include anodic aluminum oxide.
In this aspect, the power device may be connected to the circuit layer using wire bonding or flip chip bonding.
Another aspect of the present invention provides a method of fabricating the power device package, including forming an anodized layer on both a surface of a metal plate having a cavity formed on one surface thereof and an inner wall of the cavity, and then forming a circuit layer on the anodized layer; mounting a power device in the cavity so as to be connected to the circuit layer; and filling the cavity with a resin sealing material.
In this aspect, the circuit layer may include an inner circuit layer formed on the inner wall of the cavity, and an outer circuit layer formed on the surface of the metal plate and connected to the inner circuit layer.
Also, the method may further include forming a connection member on the circuit layer, after the filling the cavity with a resin sealing material.
Also, the method may further include attaching a cover member to one surface of the metal plate, forming a through hole in the cover member so as to expose the outer circuit layer, and forming an interconnection portion in the through hole so as to be connected to the outer circuit layer, after the filling the cavity with a resin sealing material.
Also, the method may further include attaching a heat sink to the other surface of the metal plate, after the filling the cavity with a resin sealing material.
In this aspect, the metal plate may be made of aluminum or an aluminum alloy, and the anodized layer may include anodic aluminum oxide.
In this aspect, in the mounting the power device in the cavity, the power device may be connected to the circuit layer using wire bonding or flip chip bonding.
The 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:
Hereinafter, a detailed description will be given of embodiments of the present invention with reference to the accompanying drawings. Throughout the drawings, the same reference numerals refer to the same or similar elements, and redundant descriptions are omitted. In the description, in the case where known techniques pertaining to the present invention are regarded as unnecessary because they would make the characteristics of the invention unclear and also for the sake of description, the detailed descriptions thereof may be omitted.
Furthermore, 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 implied by the term to best describe the method he or she knows for carrying out the invention.
As shown in
The anodized metal substrate performs a supporting function and a heat dissipation function, and provides a circuit layer 120 acting as an electrode terminal of the power device 130. The anodized metal substrate is configured such that a cavity 112 for receiving the power device is formed on a metal plate 110, an anodized layer 114 is formed on the entire surface of the metal plate 110 including the inner wall of the cavity 112, and the circuit layer 120 is formed on the anodized layer 114.
The metal plate 110 is made of aluminum (Al) or Al alloy which is relatively inexpensive and easily purchasable and has superior heat transfer properties. Because the metal plate 110 has superior heat transfer properties, it functions as a heat dissipation member for dissipating heat generated from the power device 130, thus obviating a need for an additional heat dissipation member.
The anodized layer 114 may include anodic aluminum oxide (Al2O3) having insulation performance and a relatively high heat conductivity ranging from about 10 to 30 W/mK. Because the anodized layer 114 has insulation performance, it enables the formation of the circuit layer 120 on the metal plate 110. Also because the anodized layer 114 may be formed to be thinner than a typical insulating layer, a distance between the metal plate 110 and the power device may be reduced, thereby further increasing heat dissipation performance and making the package thin.
In the present embodiment, the circuit layer 120 is formed in the cavity 112 of the metal plate 110 so as to enable the wire bonding with the power device 130, and is further formed to extend to the outer surface of the metal plate 110. Specifically, the circuit layer 120 includes an inner circuit layer 120a formed on the inner wall of the cavity 112 and an outer circuit layer 120b extending to the surface of the metal plate 110 and connected to the inner circuit layer 120a. As such, the outer circuit layer 120b is connected to an external power source and thus transfers power to the inner circuit layer 120a. Even when the cavity 112 is filled with the resin sealing material 140 and thus the inner circuit layer 120a is not directly connected to the external power source, it is possible to continue supplying power.
The power device 130 may include a high power semiconductor chip selected from among a silicon controlled rectifier, a power transistor, an insulated gate bipolar transistor, a MOSS transistor, a power rectifier, a power regulator, an inverter, a converter and combinations thereof, a diode, or a low power semiconductor chip which is responsible for controlling it.
The power device 130 may be mounted by attaching it in the form of a face-up type to the inner surface of the cavity 112 using a solder material or an epoxy resin so that the pad thereof faces upward, or by attaching it to the inner surface of the cavity 112 using sintering or heat fusion and then connecting the pad of the power device 130 to the inner circuit layer 120a using wires. Although not shown, the power device 130 may be directly mounted on the inner circuit layer 120a through flip chip bonding.
The resin sealing material 140 functions to protect not only the wires 134 but also the power device 130 from the external environment. To this end, the cavity 112 may be filled with the resin sealing material 140, for example, an epoxy molding compound.
Attached to the other surface of the anodized metal substrate is a heat sink 150 for increasing heat dissipation performance using an adhesive 152.
As shown in
As shown in
As such, in order to reduce the material cost, the cover member 160b may be attached to any region except for the region filled with the resin sealing material 140.
Fabrication of Power Device Package
As shown in
The cavity 112 may be formed by processing one surface of the metal plate 110 through a chemical or mechanical process (e.g. drilling), or by attaching a metal plate having an additional recess using soldering, arc welding, heat fusion, sintering, etc.
Next, as shown in
The anodized layer 114 may be formed by immersing the metal plate 110 made of Al or Al alloy in an electrolytic solution of boric acid, phosphoric acid, sulfuric acid or chromic acid, applying an anode to the metal plate 110 and applying a cathode to the electrolytic solution. Thereby, formed on the surface of the metal plate 110 is anodic aluminum oxide (Al2O3) which has a relatively high heat conductivity ranging from about 10 to 30 W/mK. The anodized layer 114 has insulation performance, thus enabling the formation of a circuit layer thereon, and as well is formed to be thinner than a resin insulating layer and has high heat conductivity, thus contributing to slimness of the anodized metal substrate and improving heat dissipation performance.
Next, as shown in
As such, the circuit layer 120 may be formed by performing a plating process (electroless plating and electroplating) on the anodized layer 114 thus preparing a plating layer which is then patterned.
The circuit layer 120 includes an inner circuit layer 120a formed on the inner wall of the cavity 112 and an outer circuit layer 120b formed on the surface of the metal plate 110 and electrically connected to the inner circuit layer 120a. As such, the outer circuit layer 120b formed on the surface of the metal plate 110 functions as a mounting pad connected to an external power source, and supplies power to a power device 130 through the inner circuit layer 120a. In the present invention, because the outer circuit layer 120b is formed, even when the cavity 112 is filled with the resin sealing material 140, the connection to the external power source is still possible.
Next, as shown in
The power device 130 may be mounted by attaching it in the form of a face-up type to the inner surface of the cavity 112 using a solder material or an epoxy resin so that its pad faces upward, or by attaching it to the inner surface of the cavity 112 using sintering or heat fusion and then connecting the pad of the power device 130 to the inner circuit layer 120a using wires 134. Although not shown, the power device 130 may be directly mounted on the inner circuit layer 120a through flip chip bonding, without the use of the wires 134.
Next, as shown in
The resin sealing material 140 may be charged in the cavity 112 through dispensing, transfer molding, stencil printing or the like.
Next, as shown in
The heat sink 150 may be attached using an adhesive 152 for example a thermal conductive adhesive, and may have a pin structure so that its surface area is enlarged thus maximizing heat dissipation performance.
Further, as shown in
Alternatively, as shown in
Further, a through hole 162 may be formed in the cover member 162, and an interconnection portion 170 may be formed through plating in the through hole 162 so as to connect the outer circuit layer 120b to the external power source or another electronic device.
As described hereinbefore, the present invention provides a power device package and a method of fabricating the same. According to the present invention, the power device package has a simple configuration in which a power device is mounted on an anodized metal substrate, and has improved heat dissipation performance.
Also, according to the present invention, an anodized layer which is thinner than a conventional resin insulating layer is formed on a metal plate, thus increasing heat conductivity and realizing slimness of a package.
Also, according to the present invention, the metal plate fulfils the function of a conventional copper plate, and thus there is no need to use the expensive copper plate, thereby decreasing the fabrication cost, simplifying the bonding process and reducing the bonding interface, resulting in improved heat dissipation performance.
Also, according to the present invention, an additional lead frame is not used, thus reducing the fabrication cost of the power device package.
Although the embodiments of the present invention regarding the power device package and the method of fabricating the same have been disclosed for illustrative purposes, those skilled in the art will appreciate that a variety of different 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 as falling within the scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2009-0072440 | Aug 2009 | KR | national |
