CN102339811A

CN102339811A - Circuit board with COB (Chip On Board) packaged power device

Info

Publication number: CN102339811A
Application number: CN201010238245XA
Authority: CN
Inventors: 周春东; 于冰冰; 程琦
Original assignee: APEXONE MICROELECTRONICS Co Ltd; Apexone Microelectronics Ltd
Current assignee: APEXONE MICROELECTRONICS Co Ltd; Apexone Microelectronics Ltd
Priority date: 2010-07-27
Filing date: 2010-07-27
Publication date: 2012-02-01

Abstract

The invention concerns a circuit board with a COB (Chip On Board) packaged power device. The circuit board comprises a substrate, and the power device which is packaged on the substrate by using the COB technology is arranged on the substrate, wherein a heat-dissipation metal layer which is used for heat dissipation is arranged on the surface of the substrate; a nickel-gold layer and a soft gold layer are arranged on the heat-dissipation metal layer; and through holes which penetrate through the substrate, the heat-dissipation metal layer, the nickel-gold layer and the soft gold layer are arranged below the power device. With the adoption of the manner, a large amount of heat quantities generated by the COB packaged power device can be effectively dissipated through the through holes and the heat-dissipation metal layer, thus the problem of influence on the use of the power device because of overheat is solved.

Description

Circuit board with COB package power device

[technical field]

The present invention relates to a kind of circuit board, especially relate to a kind of COB (chip on board) mode of passing through power device encapsulation circuit board on it with power device.

[background technology]

It is more and more convenient that the development of integrated circuit technique makes in people's life, and the integrated requirement for integrated circuit that improves constantly makes the device of electronic product on the unit are circuit board more and more, and power also requires increasing.Electronic device is arranged on the circuit board, multiple different packaged type occurred, and different devices uses different encapsulation to satisfy its demand.

Electronic Packaging (electronic packaging) is an indispensable one procedure after IC Chip Production is accomplished, and is the bridge of device to system.Encapsulating initial definition is: the protective circuit chip is avoided the influence (comprising the influence of physics, chemistry) of surrounding environment.Along with the development of integrated circuit technique, what especially chip passivation layer was technological updates, and the function of encapsulation is also in slowly alienation.It has been generally acknowledged that encapsulation mainly contains four big functions, i.e. power division, signal allocation, heat radiation and packaging protecting, its effect is the connection between from the IC-components to the system, comprises electricity connection and physical connection.The kind of Electronic Packaging is diversified, and needs the precision instrument of specialty to realize through complicated step.So not high at some reliability requirements, the I/O terminal number order of chip is very not many yet, but under the situation of lay special stress on device size size, the packing forms of COB occurred.

So-called COB sticks to bare chip on the interconnect substrates with conduction or non-conductive adhesive exactly, and the bonding that goes between is then realized its electrical connection.If bare chip is directly exposed in the air, pollution or artificial the damage, influence or destruction chip functions are so just seal chip and bonding wire with glue.People claim that also this packing forms is the Soft Roll envelope.With the bare chip of COB technology encapsulation is that chip body and I/O terminal are above crystal; When welding, this bare chip is bonded on the PCB with conduction/heat-conducting glue; After solidifying, with the Bonder machine with wire under the effect of ultrasonic, hot pressing, be connected on the I/O terminal welding zone and the corresponding pad of PCB of chip; After the test passes, seal up resin glue again.

With the conventional package compared with techniques, the COB technology has following advantage: cheap; Conserve space; Technical maturity.

The IC module of COB encapsulation is widely used on the product in consumer field; Though advantage is cheaply arranged; But coefficient of heat transfer is lower, can't in time the inner heat that produces of encapsulation be derived, but when the encapsulation internal temperature exceeds the operating temperature range of chip; Chip can get into the overtemperature protection state, makes that module can't operate as normal.

At present, audio frequency power amplifier generally adopts traditional packaged type, and the size of encapsulation is of all kinds, but traditional Electronic Packaging time and cost are all higher.Because audio frequency power amplifier belongs to the power-type device, and need work for a long time, the heat during work is higher, though COB encapsulation cost is lower, and the encapsulation saving of time, be difficult to solve the integrity problems such as heat radiation that audio frequency power amplifier works long hours.

Existing power stage amplifier mainly adopts the semiconductor components and devices packing forms, relies on lead frame heat radiation, circuit to connect and mechanical support.The main material of lead frame is a copper alloy, from outward appearance, similarly is a little thick copper billet.As the audio frequency amplifier of power stage, when using the COB encapsulation, the PCB system can't provide the lead frame chip cooling structure of similar thick copper billet, has limited to promoting the use of of audio frequency device COB encapsulation technology.

Therefore, need to solve power device, thereby especially audio parts is using COB to be packaged in the problem that is easy to generate the more heat transfer job insecurity on the circuit board.

[summary of the invention]

The circuit board that the purpose of this invention is to provide a kind of COB of having package power device can provide heat radiation preferably.

Above-mentioned purpose of the present invention can realize with the following methods: the circuit board with COB package power device; Comprise substrate; Be provided with use COB technology at this substrate and be packaged in the power device on the said substrate; The surface of wherein said substrate is provided with the heat radiating metallic layer that is used to dispel the heat, and on said heat radiating metallic layer, has nickel-gold layer and soft gold layer, and the below of said power device has the heat conduction setting that runs through said substrate, said heat radiating metallic layer, said nickel-gold layer and said soft gold layer.

The present invention also has following characteristic: said heat radiating metallic layer is arranged at the tow sides of substrate, and said heat conduction setting has a plurality of, and the area of said heat radiating metallic layer is a bit larger tham the area of said power device; Be on the extraneous heat radiating metallic layer of said power device and have the heat conduction setting; The said heat conduction that is arranged on the extraneous heat radiating metallic layer of power device is set to respectively there are 4 in two 2 sides of power device, and the pin of said power device uses gold thread to be connected to said soft gold layer, the black glue of encapsulation that high heat conduction is adopted in said COB encapsulation; Said heat radiating metallic layer is heat radiation copper layer; Said heat conduction is set to the heat-conducting metal body, and said heat conduction is set to through hole, has heat-conducting metal layer on the inwall of said through hole; Said heat-conducting metal layer contacts with said heat radiating metallic layer, and said heat-conducting metal layer is a heat conduction copper layer.

Through above-mentioned setting, the circuit board with COB package power device of the present invention can effectively conduct the high heat that power device produces through said heat radiating metallic layer.In addition, the use of heat conduction setting can make the heat that conducts to heat radiating metallic layer reach the another side of circuit board through convection current or conduction, thereby better radiating effect is provided.

[description of drawings]

Fig. 1 has the three-dimensional cross section view of the circuit board of COB package power device for the present invention, in order to show each layer structure between power device and circuit board.

Fig. 2 has for the present invention among the embodiment of circuit board of COB package power device, is arranged at the distribution schematic diagram of the through hole on the heat radiation copper layer.

[execution mode]

Below in conjunction with accompanying drawing and embodiment technology contents of the present invention is elaborated.

See also shown in Figure 1ly, the circuit board that the present invention has COB package power device comprises substrate 1, has heat radiating metallic layer at the tow sides of substrate 1, and in the present embodiment, this heat radiating metallic layer uses copper material, forms heat radiation copper layer 2.Though use copper material in the present embodiment, for the professional and technical personnel,, can know in conjunction with the object of the invention according to general technological know-how, use other metal material also passable, the good conductor of heat that yes preferably.In addition, this heat radiation copper layer 2 also can only be arranged at any one side of substrate 1.Just tow sides be provided with heat radiation copper layer 2 be one preferred embodiment.On this heat radiation copper layer 2, can further be provided with nickel-gold layer 3 and soft gold layer 5.Power device 4 promptly is arranged on this soft gold layer 5, and couples together through the back side and the soft gold layer 5 of silver slurry 9 with power device 4.

Please continue to consult shown in Figure 1; The heat dissipation region that forms at heat radiation copper layer 2 has a plurality of heat conduction settings that run through aforesaid base plate 1, heat radiation copper layer 2, nickel-gold layer 3 and soft gold layer 5; This heat conduction setting is through hole 6 in the present embodiment, is not only through hole 6 certainly, all can work as long as can carry out being arranged on here of effective heat conduction; For example as the heat-conducting metal body of the good conductor of heat also can, be that example describes with through hole 6 in the present embodiment just.Hole wall inboard at through hole 6 is coated with heat-conducting metal, and in the present embodiment, this heat-conducting metal adopts copper material, forms heat conduction copper 61, and this heat conduction copper 61 connects the above-mentioned heat radiation copper layer 2 that is arranged at substrate 1 positive and negative.In addition, some is arranged at the below of said power device 4 in the above-mentioned through hole 6, arrives at the position of silver slurry 9.Pin at power device 4 is connected to substrate 1 through gold thread 8, in order to transmission of electric signals.

Please combine to consult Fig. 1 and shown in Figure 2, show the distribution of the through hole 6 on the heat radiation copper layer 2.On the heat radiation copper layer 2 10 through holes 6 are set altogether, wherein the centre position is provided with 2, and respectively is provided with 4 in the position at two ends.Two middle through holes 6 are arranged at the below of power device 4.And each 4 through hole 6 at two ends are arranged at outside power device 4 coverages.

In addition,, use the black glue 7 of encapsulation of high heat conduction to carry out the COB encapsulation, can further increase radiating effect for power device 4 in the periphery of power device 4.

Through above-mentioned setting, the circuit board of the COB of having package power device of the present invention can effectively reduce the temperature of the inner power device of encapsulation, prevents that power device from damaging or the overtemperature protection after reaching uniform temperature.

Claims

1. A circuit board with a COB packaged power device, comprising a substrate, on which a power device packaged on the substrate using COB technology is provided, and it is characterized in that: the surface of the substrate is provided with a heat dissipation device for heat dissipation The metal layer has a nickel-gold layer and a soft gold layer on the heat-dissipating metal layer, and there is a heat conduction layer running through the substrate, the heat-dissipating metal layer, the nickel-gold layer, and the soft gold layer below the power device. set up.

2 . The circuit board with COB packaged power devices according to claim 1 , wherein the heat dissipation metal layer is arranged on both front and back sides of the substrate. 3 .

3 . The circuit board with COB packaged power devices according to claim 1 , wherein there are multiple heat conducting devices. 4 .

4. The circuit board with COB packaged power devices as claimed in claim 3, characterized in that: the area of the heat dissipation metal layer is slightly larger than the area of the power device, and the heat dissipation metal layer outside the range of the power device There is a heat conduction setting on it.

5. The circuit board with COB packaged power devices as claimed in claim 4, characterized in that: the heat conduction on the heat dissipation metal layer outside the range of the power devices is arranged as four on both sides of the power devices .

6 . The circuit board with COB packaged power devices according to claim 1 , wherein the pins of the power devices are connected to the soft gold layer using gold wires.

7. The circuit board with COB packaged power devices as claimed in claim 1, characterized in that: said COB package adopts high thermal conductivity packaging black glue.

8 . The circuit board with COB packaged power devices according to claim 1 , wherein the heat dissipation metal layer is a heat dissipation copper layer.

9. The circuit board with COB packaged power devices according to any one of claims 1 to 8, characterized in that: the heat conduction device is a heat conduction metal body.

10. The circuit board with COB packaged power devices according to any one of claims 1 to 8, characterized in that: the heat conduction arrangement is a through hole.

11. The circuit board with COB packaged power devices according to any one of claims 10, characterized in that: there is a heat-conducting metal layer on the inner wall of the through hole, and the heat-conducting metal layer is in contact with the heat-dissipating metal layer.

12 . The circuit board with COB packaged power devices according to claim 11 , wherein the thermally conductive metal layer is a thermally conductive copper layer. 13 .