TWM569075U - Package structure of power device - Google Patents

Abstract

A package structure of power device includes a lead frame, at least one power device, an aluminum substrate, and a package. The power devices are disposed on a first surface of the lead frame, and the aluminum substrate is disposed on a second surface of the lead frame, wherein the second surface is opposite to the first surface. The package encapsulates the lead frame, the aluminum substrate, and the power device. The heat capacity of the aluminum substrate is greater than that of the lead frame, and the projection area of aluminum substrate is equal to or less than that of the package.

Description

Power component package structure

The novel creation is related to a package structure, and in particular to a power component package structure.

The power component package structure can be used for rectifiers, vehicle generators, and high power module generators. In the technical field of a vehicle generator, in order to perform an AC-DC conversion operation, a rectifier bridge is often provided. The rectifier bridge can be constructed of power components and used to provide a rectified voltage as a basis for driving the load.

When the load of the generator is instantaneously removed, a so-called load dump phenomenon occurs. When the dumping phenomenon occurs, the voltage amplitude will change instantaneously, and instantaneous high heat is generated on the power component, so that the junction temperature of the power component rises, which may cause damage of the power component package structure.

However, at present, the design of the power component package structure is mostly aimed at reducing the thermal resistance of the package structure under steady state use, that is, to reduce the steady-state thermal resistance of the package structure, and to transiently relate to transient high heat. Thermal resistance, there is no suitable solution.

The novel creation provides a power component package structure, which can simultaneously reduce the steady state thermal resistance and transient thermal resistance of the power component package structure.

The novel power component package structure comprises a lead frame, at least one power component, an aluminum substrate and a package. The lead frame has opposing first and second surfaces. The power component is disposed on the first surface of the lead frame, and the aluminum substrate is disposed on the second surface of the lead frame. The package is a package lead frame, an aluminum substrate and a power component. The heat capacity of the aluminum substrate is greater than the heat capacity of the lead frame, and the projected area of the aluminum substrate is less than or equal to the projected area of the package.

In an embodiment of the present invention, the power component package structure further includes a control system and an insulating layer. The control system is disposed on the first surface of the lead frame and electrically connected to the power component, and the insulating layer is interposed between the lead frame and the control system.

In an embodiment of the present invention, the lead frame is composed of a plurality of blocks.

In an embodiment of the present invention, the power component is a plurality of power components respectively disposed on different blocks.

In an embodiment of the novel creation, at least two of the power components described above are disposed on the same block.

In an embodiment of the present invention, at least one of the power elements described above is disposed on the block in a flip chip manner.

In an embodiment of the present invention, the power component package structure may further include a plurality of conductive structures electrically connected to one block and each power component.

In an embodiment of the present invention, the conductive structure comprises a metal wire or a metal sheet.

In an embodiment of the present invention, the material of the lead frame is one selected from the group consisting of copper, aluminum, gold, silver, diamond or graphene and alloy compounds thereof.

In an embodiment of the present invention, the thickness of the aluminum substrate is greater than the thickness of the lead frame.

In an embodiment of the present invention, the volume of the aluminum substrate is larger than the volume of the lead frame.

In an embodiment of the present invention, part of the aluminum substrate is exposed outside the package.

In an embodiment of the present invention, the aluminum substrate is composed of a plurality of aluminum blocks, and the aluminum blocks are respectively disposed directly under the power element.

In an embodiment of the present invention, the lead frame is in direct contact with the aluminum substrate.

In an embodiment of the present invention, the power component package structure may further include a conductive adhesive layer between the lead frame and the aluminum substrate.

In an embodiment of the present invention, the power component package structure may further include a plurality of temperature measuring components respectively disposed on each of the power components.

In an embodiment of the novel creation, the power component includes a field effect transistor controlled by voltage or current.

In an embodiment of the present invention, the power device includes a metal oxide semiconductor field effect transistor (MOSFET), an insulated gate bipolar transistor, or a gallium nitride transistor.

In an embodiment of the present invention, the power component package structure is a power component package structure for a vehicle.

In an embodiment of the present invention, the above-described power component package structure for a vehicle includes a rectifier or a motor drive device for a vehicle generator.

Based on the above, the present invention can reduce the steady-state thermal resistance of the power component package structure by using a high specific heat capacity aluminum substrate with a high thermal conductivity lead frame, and can also reduce the transient thermal resistance of the power component package structure and improve the package structure. The processing capacity of transient loads such as throwing and short circuits.

The above described features and advantages of the present invention will become more apparent and understood from the following description.

The exemplified embodiments of the present invention are fully described below with reference to the drawings, but the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments described herein. In the drawings, the size and thickness of various regions, regions, and layers may not be For the sake of easy understanding, the same elements in the following description will be denoted by the same reference numerals.

1 is a perspective view of a power component package structure in accordance with an embodiment of the present invention.

Referring to FIG. 1 , the power device package structure 100 of the present embodiment includes a lead frame 102 , an aluminum substrate 104 , a power device 106 , and a package 108 . The lead frame 102 has opposite first and second surfaces 102a, 102b, and the lead frame 102 itself is a high thermal conductivity material, and may be composed of a plurality of mutually isolated blocks 110a to 110e, wherein the material of the lead frame 102 is selected, for example. It is one of materials including copper, aluminum, gold, silver, diamond or graphene and alloy compounds thereof. The power component 106 is disposed on the first surface 102a of the lead frame 102, and there are several power components 106 in this embodiment; however, the present invention is not limited thereto, and the number of power components 106 may be only one. For example, at least one of the power elements 106 can be flip-chip disposed on the blocks 110a-110e. The power components 106 are, for example, voltage or current controlled field effect transistors 106a-106d, or, for example, metal oxide semiconductor field effect transistors (MOSFETs), insulated gate bipolar transistors, gallium nitride transistors, or other power transistors. The aluminum substrate 104 is disposed on the second surface 102b of the lead frame 102, wherein the aluminum substrate 104 itself is a high heat capacity material and may be composed of a plurality of plates 104a to 104b.

In the present embodiment, the aluminum substrate 104 is preferably disposed directly under the power element 106. For example, the plate 104a of the aluminum substrate 104 is located directly below the field effect transistors 106a and 106b, and the plate 104b of the aluminum substrate 104 is located directly below the field effect transistors 106c and 106d. The heat capacity of the aluminum substrate 104 is generally greater than the heat capacity of the lead frame 102, and the thickness of the aluminum substrate 104 can be greater than the thickness of the lead frame 102 and/or the volume of the aluminum substrate 104 can be greater than the volume of the lead frame 102. The aluminum substrate 104 can be a pure aluminum substrate or an aluminum alloy substrate. In one embodiment, the lead frame 102 can be in direct contact with the aluminum substrate 104. In another embodiment, a conductive adhesive layer (not shown) can be disposed between the lead frame 102 and the aluminum substrate 104. The package body 108 encapsulates the lead frame 102 , the aluminum substrate 104 and the power component 106 , and the projected area of the aluminum substrate 104 is less than or equal to the projected area of the package 108 . A portion of leadframe 102 (e.g., blocks 110b, 110c, 110d, 110e) may protrude from package body 108 for use as an end point for electrical connections. In the present embodiment, the material of the package 108 is, for example but not limited to, an epoxy resin, a biphenyl resin or an unsaturated polyester. Since the power component package structure 100 of the present embodiment may be a power component package structure for a vehicle, the power component package structure 100 may further include a control system disposed on the first surface 102a of the lead frame 102 and electrically connected to the power component 106. 112 (such as a control IC, a capacitor and other circuit components), and an insulating layer (not shown) is disposed between the lead frame 102 and the control system 112. The insulating layer electrically isolates the control system 112 from the lead frame 102 below it. (ie block 110a). The control ICs in the control system 112 can be electrically connected to the field effect transistors 106a-106d on the lead frame 102 via metal wires (not shown) for transmitting control signals to the field effect transistors 106a-106d. The above-described vehicular power component package structure includes a rectifier or motor drive device for a vehicle generator.

When the power component package structure 100 of the present invention is applied to a rectifier of a vehicle generator, the alternating current continuously enters the power component package structure 100 and is converted into a direct current by the power component 106, and the heat generated during the conversion causes power. The temperature of the element 106 rises, and at this time, the lead frame 102 having high thermal conductivity in this embodiment can lower the steady-state thermal resistance. The thermal energy generated by the voltage surge generated immediately after the load current is removed can be quickly absorbed by the aluminum substrate 104 having a high heat capacity in the embodiment, and the junction temperature of the power component 106 is lowered. .

For example, for an automobile generator with 50A power generation, the transient energy generated when it is thrown off is about 97.2J. If a copper lead frame is used as the lead frame 102 of the present invention, the heat capacity design can be adopted. It is 0.5 J·°C ^-1 , and as long as the heat capacity of the aluminum substrate 104 is greater than 0.5 J·° C ^-1 , the junction temperature of the power element 106 can be ensured to be not higher than 350 ° C. In this embodiment, the heat capacity of the aluminum substrate 104 can be further designed to be 1.43 J·° C ^-1 , that is, the junction temperature of the power component 106 can be maintained not higher than 190 ° C to ensure that the power component 106 does not cause The junction temperature is too high and damaged.

2A is a front view of a power device package structure in accordance with another embodiment of the present invention, and FIG. 2B is a rear view of FIG. 2A. 3 is a perspective view of the power device package structure of FIG. 2A with the package omitted to clearly show the front side configuration of the power device package structure.

Referring to FIG. 2A, FIG. 2B and FIG. 3 simultaneously, the power component package structure 200 of the present embodiment basically includes a lead frame 202, an aluminum substrate 204, a power component 206, and a package body 208. The power component 206 is disposed on a surface of the lead frame 202, the aluminum substrate 204 is disposed on the other surface of the lead frame 202, and a portion of the aluminum substrate 204 is exposed outside the package 208. The lead frame 202 in this embodiment is composed, for example, of a plurality of mutually isolated blocks 202a-202e, wherein the block 202a has reference ground pins 210a and 210b, the block 202b has a phase output pin 212a, and the block 202c has a phase. The output pin 212b, the block 202d has a power pin 214a, and the block 202e has a power pin 214b. If the power component package structure 200 is used as a power component package structure for a vehicle, the power pins 214a and 214b can be coupled to the vehicle battery, and the phase output pins 212a and 212b respectively generate a plurality of rectified signals, and the reference ground pin 210a, 210b can be coupled to a reference ground. The above-described vehicular power component package structure includes a rectifier or motor drive device for a vehicle generator. When the package 208 covers the lead frame 202, the aluminum substrate 204 and the power component 206, the pins 210a, 210b, 212a, 212b, 214a, 214b will protrude from the package 208, as shown in FIGS. 2A and 2B. The leadframe 202 can also include a plurality of pin blocks 216 that are separate from the block 202a and can be routed, copper clips or other conductors to the leadframe 202 or components thereon (such as power component 206 or external power source). Etc.). The lead frame 202 can directly contact the aluminum substrate 204, or a conductive adhesive layer (not shown) is disposed between the lead frame 202 and the aluminum substrate 204. The physical characteristics of the lead frame 202 in this embodiment can be referred to the previous embodiment, and therefore will not be described again.

With continued reference to FIG. 3, the power components 206 in this embodiment, such as field effect transistors 206a-206d, or, for example, metal oxide semiconductor field effect transistors (MOSFETs), insulated gate bipolar transistors, gallium nitride transistors, or Other power transistors. In the present embodiment, the power components 206 are respectively disposed on different blocks of the lead frame 202, but the novel creation is not limited thereto. For example, in FIG. 3, at least two of the power elements 206 can be disposed on the same block, that is, the field effect transistors 206a and 206b are disposed on the block 202b of the lead frame 202, and the field effect transistors 206c and 206d are disposed on the block. The block 202c is on the block 202c. The field effect transistor 206a can be electrically connected to the block 202a and the block 202b through the conductive structure 218, and a Zener diode 220 can be added to the block 202b, and the Zener diode 220 can be added through the conductive structure 218. The pole body 220 is connected between one end (for example, a drain) of the field effect transistor 206a and the other end (for example, a source) as a protective element of the field effect transistor 206a, but the present invention is not limited thereto. In another embodiment, since the aluminum substrate 204 having a high heat capacity can reduce the transient thermal resistance, the output diode 220 is not required to be disposed, and the conductive structure 218 is electrically connected to one of the blocks and the respective power components. . In other words, the field effect transistor 206a can also be directly electrically connected to the block 202b of the lead frame 202 through the conductive structure 218, and the field effect transistor 206b can also be electrically connected to the block 202d through the conductive structure 222.

The other effect transistor 206c can also be electrically connected to the block 202a and the block 202c through another conductive structure 218, and another additional diode 220 can be added to the block 202c and connected to the field through the conductive structure 218. The one end of the effect transistor 206c (for example, the drain) and the other end (for example, the source) serve as a protective element of the field effect transistor 206c. However, the present invention is not limited thereto, and the above-mentioned shunt diode may be omitted. 220, directly solve the problem caused by the transient thermal resistance via the aluminum substrate 204, so that the field effect transistor 206c can be directly electrically connected to the block 202c of the lead frame 202 through the conductive structure 218. The field effect transistor 206d can be electrically connected to the block 202e through another conductive structure 222. The conductive structures 218 and 222 described above are, for example, metal wires, metal sheets or other suitable structures.

Referring to FIG. 2B, the aluminum substrate 204 has three plates 204a, 204b and 204c, and the plate 204a is disposed directly under the field effect transistors 206a and 206b of FIG. 3, and the plate 204b is disposed in the field effect of FIG. Directly below the crystals 206c and 206d, the panel 204c is disposed directly below the control system 224 of FIG. 3, however, the novel creation is not limited thereto. In view of the effect of reducing the transient thermal resistance, the aluminum substrate 204 may be disposed directly below the power element 206; in other words, the plate 204c may be omitted. In FIG. 2B , a portion of the aluminum substrate 204 is exposed outside the package 208 , and the projected area of the aluminum substrate 204 does not exceed the package 208 . The material selection of the aluminum substrate 204 can be referred to the previous embodiment, and therefore will not be described again. The package 208 is sealed, for example, by a molding process, and the power component 206, the lead frame 202, and the aluminum substrate 204 are sealed. In this embodiment, the material of the package 208 may include an epoxy resin, a biphenyl resin, an unsaturated polyester or a ceramic material.

When a large current flows from the reference ground pins 210a and 210b or the phase output pins 212a and 212b through the lead frame 202 into the field effect transistors 206a to 206d, the field can be reduced by the aluminum substrate 204 having a high heat capacity in this embodiment. The high junction temperature caused by the high heat generated by the effect transistors 206a to 206d instantaneously. Therefore, the design of the present embodiment can prevent the power component package structure 200 from being damaged.

In addition, the power component package structure 200 in this example may further include a control system 224 (such as a control IC, capacitors, and other circuit components) disposed on the block 202a of the leadframe 202 and on the leadframe 202 and the control system 224. An insulating layer (not shown) is disposed between the control system 224 and the lead frame 202 (i.e., block 202a) below it. The control ICs in the control system 224 can be electrically connected to the field effect transistors 206a-206d on the lead frame 202 and/or the lead frame 104 via wire bonding (not shown) for transmitting control signals to the field effect transistor. 206a~206d.

In addition, the power component package structure 200 in this example may further include a plurality of temperature measuring components 226 disposed on the power component 206, respectively. The temperature measuring element 226 is, for example, a thermistor. For example, in FIG. 3, the temperature measuring elements 226 can be respectively disposed on the conductive structures 218 above the field effect transistors 206a-206d, and electrically connected to the control system 224 through metal wires (not shown), and transmit temperature detection. The results are measured to the system IC in control system 224. In other embodiments, the temperature measuring elements 226 can also be disposed on the leadframe 202 adjacent the power component 206, respectively.

In order to verify the above effects, the following experiments are illustrated, but the novel creation is not limited to the following experiments.

<Experimental example>

A power component package structure as shown in FIGS. 2A and 2B is fabricated, and then the load test is performed according to the ISO-7637-2 standard, the test conditions of the following Table 1 and Table 2, after five tests, and the interval between each test is For 60 seconds, the results of the load-bearing endurance after the test are shown in Table 3 below and Figure 4.

<Comparative example>

The difference between the comparative example and the experimental example is that the aluminum substrate is not provided in the power element package structure of the comparative example. Then, the above-described throwing test was also performed, and the results are shown in Table 3 below and FIG.

Table I  <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> Parameters</td><td> 12 System </td><td> 24 System </ Td></tr><tr><td> Pulse Voltage U_S</td><td> 79V ~ 101V </td><td> 151V ~ 202V </td ></tr><tr><td> Supply Voltage U_A</td><td> 13.5V </td><td> 27V </td></tr ><tr><td> Internal Resistance R_i</td><td> 0.5Ω ~ 4Ω </td><td> 1Ω ~ 8Ω </td></tr ><tr><td> Pulse Voltage with Load Dump Suppression U_S* </td><td> 35 </td><td> 65 </td ></tr><tr><td> Pulse Width t_d</td><td> 40ms ~ 400ms </td><td> 100ms ~ 350ms </td> </tr><tr><td> Rise Time t_r</td><td> 5ms ~ 10ms </td><td> 5ms ~ 10ms </td> </tr></TBODY></TABLE>

Table II  <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> Transient Voltage Suppression (TVS) Method</td><td> Low bond </td> <td> Up bond </td></tr><tr><td> Pulse voltage U_S</td><td> V </td><td> 79 </td> <td> 101 </td></tr><tr><td> Output Resistance R_i</td><td> Ω </td><td> 0.5 < /td><td> 4.0 </td></tr><tr><td> Test object V_WM (DUT V_WM) V_{WM , DUT}</td><td> V </td><td> 24.0 </td><td> 24.0 </td></tr><tr><td> Peak Current I_peak</td><td> A </td><td> 158.0 </td><td> 25.3 </td></tr><tr><td> Peak Power on DUT P_{peak, DUT}</td><td> W </td><td> 3,792 </td><td> 606 </td>< /tr><tr><td> Pulse width t_d</td><td> Ms </td><td> 30 </td><td> 321 </td></ Tr><tr><td> Load Dump Energy E_{Load, Dump}</td><td> J </td><td> 56.6 </td><td> 97.2 </td></tr></TBODY></TABLE>

Table 3  <TABLE border="1" borderColor="#000000" width="85%"><TBODY><tr><td> </td><td> Experimental </td><td> Comparative Example </td ></tr><tr><td> Heat Capacity (J/°C) </td><td> 2.5 </td><td> 1.0 </td></tr><tr><td> Energy (J) </td><td> 84.0 </td><td> 84.0 </td></tr><tr><td> Temperature rise (°C) </td><td> 171 </td ><td> 278 </td></tr><tr><td> Power Element Center Temperature T_j(°C) </td><td> 193 </td><td > 300 </td></tr></TBODY></TABLE>

As can be seen from the test results of FIG. 4 and Table 3, since the power element package structure of the experimental example is provided with an aluminum substrate having a high heat capacity, when the same throwing energy is applied, the temperature rise temperature of the experimental example is higher than that of the comparative example. The temperature was much lower, and the junction temperature of the power element of the experimental example was much lower than the junction temperature of the power element of the comparative example. It can be seen that the aluminum substrate with high heat capacity disposed under the lead frame can reduce the transient thermal resistance of the power component package structure, and the temperature rise temperature and the junction temperature of the power component are significantly improved.

In summary, the aluminum component substrate with high heat capacity and the high thermal conductivity lead frame in the power component package structure of the present invention can not only reduce the steady-state thermal resistance, but also reduce the transient thermal resistance. Therefore, the novel power component package structure is suitable for a rectifier or motor drive device of a high-power vehicle generator.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the novel creation, and any person skilled in the art can make some changes without departing from the spirit and scope of the novel creation. Retouching, the scope of protection of this new creation is subject to the definition of the scope of the patent application attached.

100,200‧‧‧Power component package structure

102, 202‧‧‧ lead frame

102a‧‧‧ first surface

102b‧‧‧second surface

104, 204‧‧‧ aluminum substrate

104a, 104b, 204a, 204b, 204c‧‧‧ sections

106, 206‧‧‧ Power components

106a, 106b, 106c, 106d, 206a, 206b, 206c, 206d‧‧‧‧ field effect transistor

108, 208‧‧‧ package

110a, 110b, 110c, 110d, 110e, 202a, 202b, 202c, 202d‧‧‧ blocks

112, 224‧‧‧ Control system

210a, 210b‧‧‧ reference grounding pin

212a, 212b‧‧‧ phase output pins

214a, 214b‧‧‧ power pin

216‧‧‧ pin block

218, 222‧‧‧ conductive structure

220‧‧‧Jenner diode

226‧‧‧Thermal Resistor

1 is a perspective view of a power component package structure in accordance with an embodiment of the present invention. 2A is a front elevational view of a power component package structure in accordance with another embodiment of the present invention. 2B is a schematic rear view of FIG. 2A. 3 is a perspective view of the power component package structure of FIG. 2A. Fig. 4 is a graph showing the results of the throwing test of the experimental example and the comparative example.

Claims (20)

A power component package structure includes: a lead frame; at least one power component disposed on the first surface of the lead frame; an aluminum substrate disposed on the second surface of the lead frame, the second surface being opposite to the first surface The heat capacity of the aluminum substrate is greater than the heat capacity of the lead frame; and the package encapsulating the lead frame, the aluminum substrate and the power component, wherein a projected area of the aluminum substrate is less than or equal to a projected area of the package. The power device package structure of claim 1, further comprising: a control system disposed on the first surface of the lead frame and electrically connected to the power component; and an insulating layer interposed therebetween Between the lead frame and the control system. The power device package structure of claim 1, wherein the lead frame is composed of a plurality of blocks. The power component package structure of claim 3, wherein the power component comprises a plurality of power components, respectively disposed on different blocks. The power component package structure of claim 4, wherein at least two of the power components are disposed on the same block. The power device package structure of claim 5, wherein at least one of the power elements is disposed on the block in a flip chip manner. The power component package structure of claim 4, further comprising a plurality of conductive structures electrically connecting one of the blocks to each of the power components. The power device package structure of claim 7, wherein the conductive structures comprise metal wires or metal sheets. The power device package structure of claim 1, wherein the material of the lead frame is one selected from the group consisting of copper, aluminum, gold, silver, diamond or graphene and alloy compounds thereof. The power device package structure of claim 1, wherein the thickness of the aluminum substrate is greater than the thickness of the lead frame. The power component package structure of claim 1, wherein the volume of the aluminum substrate is greater than the volume of the lead frame. The power device package structure of claim 1, wherein a portion of the aluminum substrate is exposed outside the package. The power device package structure of claim 1, wherein the aluminum substrate is composed of a plurality of plates, and the plates are respectively disposed directly under each of the power elements. The power device package structure of claim 1, wherein the lead frame is in direct contact with the aluminum substrate. The power component package structure of claim 1, further comprising a conductive adhesive layer interposed between the lead frame and the aluminum substrate. The power component package structure according to claim 4, further comprising a plurality of temperature measuring components respectively disposed on the power components. The power device package structure of claim 1, wherein the power device comprises a voltage or current controlled field effect transistor. The power device package structure of claim 1, wherein the power device comprises a metal oxide semiconductor field effect transistor, an insulating gate bipolar transistor or a gallium nitride transistor. The power device package structure according to any one of claims 1 to 18, which is a power component package structure for a vehicle. The power component package structure of claim 19, wherein the vehicle power component package structure comprises a rectifier or motor drive device for a vehicle generator.