WO2018137560A1

WO2018137560A1 - Power module and manufacturing method therefor

Info

Publication number: WO2018137560A1
Application number: PCT/CN2018/073368
Authority: WO
Inventors: 李慧; 杨胜松; 廖雯祺; 杨钦耀; 李艳; 张建利; 曾秋莲
Original assignee: 比亚迪股份有限公司
Priority date: 2017-01-24
Filing date: 2018-01-19
Publication date: 2018-08-02
Also published as: CN108346645A

Abstract

A power module and a manufacturing method therefor, the power module comprising: an insulating dielectric substrate (10) having a first conductive layer (12) on an upper surface thereof; a switch tube chip (20) and a diode chip (30), wherein the chips (20, 30) are adhered onto the upper surface of the insulating dielectric substrate (10); an insulating layer (40) covering the insulating dielectric substrate (10) and cladding the chips (20, 30) inside, wherein the insulating layer (40) is provided with a through hole (42) located above the chips (20, 30), and the through hole (42) is filled with a conductive substance; and a second conductive layer (50) arranged on the insulating layer (40), wherein the second conductive layer (50) is electrically connected to the chips (20, 30) through the conductive substance. The package does not require opening a plastic packaging mould, thus saving on production costs. Additionally, a power semiconductor chip is electrically connected with an upper conductive layer by providing the through hole (42) on the insulating layer (40) and filling the conductive substance therein, thereby reducing the size of the module and being advantageous for miniaturizing the module.

Description

Power module and manufacturing method thereof

The present application claims priority to Chinese Patent Application No. JP-A No. No. No. No. No. No. No. No. No. No. No. No. No. No. No. in.

Technical field

The present application relates to the field of hybrid integrated circuits, and in particular to a power module and a method of fabricating the same.

Background technique

A power semiconductor module is a device that packages a plurality of semiconductor chips together in a certain circuit structure. In an IGBT (Insulated Gate Bipolar Transistor) module, the IGBT chip and the diode chip are integrated on a common substrate, and the power device of the power semiconductor module is insulated from the mounting surface thereof (ie, the heat sink) .

Conventional power semiconductor module molding requires mold opening and high cost. In addition, the power semiconductor module includes a supporting electrical adapter block, which makes the module larger in size and less integrated.

Summary of the invention

The object of the present invention is to provide a power module and a manufacturing method thereof, which are intended to solve the problem that a conventional power semiconductor module needs to be opened and includes a supporting electrical switch block, and the module has a large volume.

The invention provides a power module comprising:

An insulating dielectric substrate having a patterned first conductive layer on an upper surface thereof;

At least one switch tube chip and at least one diode chip, the switch tube chip and the diode chip are attached on an upper surface of the insulating dielectric substrate to form an electrical connection with the first conductive layer;

An insulating layer covering the insulating dielectric substrate, the switching tube chip and the diode chip are covered, the insulating layer is provided with a through hole penetrating the upper and lower surfaces thereof, and the through hole is filled with a conductive substance ;

a patterned second conductive layer disposed on the insulating layer, wherein the second conductive layer is electrically connected to the first conductive layer through the conductive material, and the switch chip is formed by the conductive material Connected to the diode chip circuit.

The invention also provides a method for manufacturing a power module, comprising the following steps:

Providing an insulating dielectric substrate having a first conductive layer on the upper surface;

Providing at least one switch chip and at least one diode chip on the first conductive layer to form an electrical connection with the first conductive layer;

An insulating layer is disposed on the first insulating dielectric substrate to encapsulate the switch chip and the diode chip;

Providing a second conductive layer on the insulating layer, opening a through hole penetrating the insulating layer and the second conductive layer, and filling a conductive material in the through hole, so that the second conductive layer passes through the through hole The conductive material inside is electrically connected to the first conductive layer, and the switch transistor chip and the diode chip are electrically connected.

Compared with the prior art, the present invention has at least the following advantages:

The above power module and its manufacturing method module package do not need to be opened and sealed, which saves production cost; in addition, the power semiconductor chip is electrically connected by opening a through hole in the insulating layer and filling the conductive material with the upper conductive layer, thereby reducing the module. The volume is conducive to the miniaturization of the module.

DRAWINGS

1 is a schematic structural view of a power module according to a first embodiment of the present invention;

2 is a schematic structural diagram of a power module according to a second embodiment of the present invention;

3 is a schematic structural diagram of an embodiment of a power module overall layout according to the present invention;

4 is a schematic structural view of a heat dissipation flat plate according to an embodiment of the present invention;

5 is a flow chart of a method of fabricating a power module in accordance with a preferred embodiment of the present invention.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to FIG. 1 to FIG. 4 , the power module in the preferred embodiment of the present invention includes an insulating dielectric substrate 10 , at least one switch chip 20 , at least one diode chip 30 , an insulating layer 40 , and a second conductive layer 50 .

The insulating dielectric substrate 10 has oppositely disposed upper and lower surfaces, at least one of which is coated with a metal, and the intermediate layer is a ceramic layer 11. In this embodiment, the upper surface of the insulating dielectric substrate 10 is covered with a metal to form a patterned first conductive layer 12, and the lower surface may be covered with a metal to form another patterned conductive layer 13. Alternatively, the heat dissipating fins 14 may be directly disposed (see figure 2).

The switch tube chip 20 in this embodiment is an IGBT, and the diode chip 30 is an FRD (Fast Recovery Diode). The power module has one or more IGBTs and one or more FRDs to constitute a drive circuit. The upper and lower surfaces of the switch tube chip 20 have polarity pins. In this embodiment, the upper surface of the switch tube chip 20 has two polarity pins, which are a gate and an emitter, respectively, and a lower surface has a collector. The upper surface of the diode chip 30 has an anode, and the lower surface has a cathode, or vice versa.

The switch tube chip 20 and the diode chip 30 are attached to the upper surface of the insulating dielectric substrate 10 to form an electrical connection with the first conductive layer 12. Specifically, when a circuit pattern is formed on the first conductive layer 12, and the switch chip 20 and the diode chip 30 are attached to the circuit pattern by soldering or crimping, the polarity pins of the lower surface and the corresponding circuit patterns are formed. A circuit connection is formed to lead.

An insulating layer 40 covers the insulating dielectric substrate 10, and the switching transistor chip 20, the diode chip 30, and the first conductive layer 12 are covered, and the insulating layer 40 is covered on the insulating dielectric substrate by lamination. 10 on. Specifically, in the product, the lower surface of the insulating layer 40 is provided with a recess for accommodating the switch tube chip 20 and the diode chip 30. The predetermined position of the insulating layer 40 defines a plurality of through holes 42 extending through the upper and lower surfaces thereof. As shown in FIG. 1 and FIG. 2 , the plurality of through holes 42 extend through the insulating layer 40 to the switch tube chip 20 , the diode chip 30 , the first conductive layer 12 and the second conductive layer 50 , respectively, and the through holes 42 . A conductive material electrically connected to the switch chip 20, the diode chip 30, the first conductive layer 12, and the second conductive layer 50 is filled therein. As shown in FIG. 3, the plurality of through holes 42 extend through the second conductive layer 50 and the insulating layer 40 to the switch chip chip 20, the diode chip 30, and the first conductive layer 12, respectively, and the through holes 42 are filled with A conductive material electrically connected to the switch chip 20, the diode chip 30, the first conductive layer 12, and the second conductive layer 50. Preferably, under the premise of ensuring the reliability of the bonding between the metallized via 42 and the chip, the through holes 42 of the same circuit connection path are disposed as much as possible to ensure the overcurrent capability of the circuit and improve the heat dissipation capability of the upper portion of the chip.

In the manufacturing process, in the embodiment, the insulating layer 40 is formed by pre-pregnant heating and curing, and at the same time, the conductive material in the through hole 42 is simultaneously metalized; wherein the prepreg is mainly composed of a resin and a reinforcing material. The reinforcing material may be a fiberglass cloth, a paper base, a composite material or the like, and the coefficient of thermal expansion of the prepreg is matched with the thermal expansion coefficient of the switch tube chip 20 and the diode chip 30 to prevent the power device from being mismatched with the thermal expansion coefficient of the packaging material. The failure of the device is subject to excessive stress.

The second conductive layer 50 is disposed on the insulating layer 40, specifically, laminated on the insulating layer 40 by lamination. The second conductive layer 50 is electrically connected to the switch chip 20, the diode chip 30, and the first conductive layer 12 through the conductive material, and the switch chip 20 and the diode chip 30 are electrically connected by the conductive material. In this embodiment, a circuit pattern is formed on the second conductive layer 50, and the polarity pins on the upper surface of the switch tube chip 20 are electrically connected to the corresponding circuit patterns for extraction. In this manner, the switch chip 20 is electrically connected to the second conductive layer 50 through the through hole 42 which is formed on the insulating layer 40, thereby replacing the electrical transfer block to achieve electrical connection, thereby reducing the volume of the module and facilitating the module. miniaturization.

The insulating dielectric substrate 10 in the listed embodiment is not limited to a DBC (Direct Bond Copper) substrate, and may be a DBA (Direct Bond Aluminum) substrate, or any other surface-covered metal insulating medium. Substrate, refer to Figure 1. In another embodiment, the insulating dielectric substrate 10 may be a copper-clad ceramic substrate having a surface coated with copper and the other surface provided with heat dissipating fins 14, as shown in FIG.

In this embodiment, the second conductive layer 50 is a conductive metal sheet, and may be made of a copper sheet, an aluminum sheet or other conductive metal material. In other embodiments, the second conductive layer 50 may be made of a metal coated with a lower surface of another insulating dielectric substrate. Another insulating dielectric substrate has opposite upper and lower surfaces, at least one of which is coated with a metal to form a second conductive layer 50, and the intermediate layer is a ceramic layer. The upper surface may be coated with metal to form another conductive layer, and heat dissipating fins may also be provided.

Specifically, the power module further includes a lead terminal 60 (ie, a power module pin), and one end of the lead terminal 60 is fixedly electrically connected to the first conductive layer 12 or the second conductive layer 50, and the through hole 42 is matched. The conductive material inside is electrically connected to the corresponding polarity pins of the switch tube chip 20 and the diode chip 30, and the other end of the lead terminal 60 is outwardly extended. The lead terminal 60 is for taking the switch tube chip 20 and the diode chip 30 out of the terminals of the circuit in a preset circuit for connection with an external circuit. The lead terminal 60 may be fixed to the first conductive layer 12 or may be fixed to the second conductive layer 50.

In this embodiment, the first terminal 12 is fixed to the first conductive layer 12 as an example.

The lead terminal 60 includes a control terminal 62 including an emitter power terminal 61A and a collector power terminal 61B, and a collector power terminal 61B, the first conductive layer 12 including a first circuit pattern 121 and a first portion on opposite sides of the power module The two circuit patterns 122 include a emitter pad 121A and a collector pad 121B which are disposed side by side on the same side of the power module. The switch pin chip 20 and the polarity pin on the lower surface of the diode chip 30 are electrically connected to the collector pad 121B of the first circuit pattern 121, and the collector power terminal 61B is electrically connected to the collector pad 121B; The polarity pins of the upper surface of the chip 20 and the diode chip 30 are electrically connected to the emitter pads of the first circuit pattern 121 through the conductive materials in the corresponding through holes 42 and the second conductive layer 50, respectively. 121A and the second circuit pattern 122, the control terminal 62 and the second circuit pattern 122 are soldered, and the emitter power terminal 61A and the emitter pad 121A of the first circuit pattern 121 are soldered. It can be understood that the second circuit pattern 122 is also a pin pad.

More specifically, the second conductive layer 50 includes a third circuit pattern 51 and a fourth circuit pattern 52. The first circuit pattern 121 is connected to the switch chip through the conductive material in the corresponding through hole 42 and the third circuit pattern 51. 20 and a polarity pin on the upper surface of the diode chip 30. The second circuit pattern 122 is connected to the polarity pin of the upper surface of the switch tube chip 20 through the conductive material in the corresponding through hole 42 and the fourth circuit pattern 52. In this embodiment, the switch tube chip 20 is electrically connected to the emitter pad 121A of the first circuit pattern 121, and is electrically connected to the second circuit pattern 122, and is connected to the collector of the first circuit pattern 12. The pad 121B is electrically connected to a collector.

Figure 3 is a schematic diagram of the overall layout of the power module. The filled area in the figure is substantially graphically patterned for the first conductive layer 12, and the blackened area of the wire frame is substantially graphically patterned for the second conductive layer 50. The switch tube chip 20 and the diode chip 30 are soldered to the corresponding positions of the first conductive layer 12, and the control terminal 62 and the power terminal 61 are also soldered to the corresponding positions of the first conductive layer 12, and the chip polarity and the corresponding terminal are made via the metalized through holes 42. Form an electrical connection. The control terminal 62 and the power terminal 61 are respectively located on both sides of the module, and the low voltage control end is away from the high voltage power end, which reduces the electrical interference of the high voltage end to the low voltage end, and improves the reliability of the control end.

Specifically, referring to FIGS. 1 , 2 and 3 , the power module further includes a heat sink 70 that is disposed on a lower surface of the insulating dielectric substrate 10 and/or an upper surface of the second conductive layer 50 . The heat sink 70 may be directly formed of a metal-clad insulating dielectric substrate 10 (e.g., heat dissipating fins 14), or may be separately provided externally. The heat sink 70 can be separately disposed on the lower surface of the power module, or can be disposed on the upper and lower surfaces of the power module to achieve double-sided heat dissipation. Specifically, the lower surface of the insulating dielectric substrate 10 and/or the upper surface of the second conductive layer 50 are connected to the heat sink 70 through the insulating thermally conductive adhesive 80. The heat sink 70 is a heat dissipating fin or a flat heat pipe. Figure 4 is a schematic view of a flat heat pipe. The heat generated by the switch tube chip 20 and the diode chip 30 is conducted to the heat pipe evaporation surface 71, and the working fluid 72 in the capillary absorbs heat and vaporizes and fills the steam chamber. The condensing surface 73 of the flat heat pipe 70 is cooled by circulating cooling liquid. The steam 90 is recondensed into a liquid on the condensation surface 73. Under the action of the capillary suction force of the capillary core 74, the liquid re-flows back to the evaporation surface 71, and the above steps are repeated to achieve circulating heat dissipation.

In addition, in conjunction with FIG. 1 to FIG. 5, a manufacturing method capable of manufacturing the above power module is further disclosed, including the following steps:

S110, an insulating dielectric substrate 10 having a first conductive layer 12 on its upper surface is disposed.

In this step, the insulating dielectric substrate 10 is provided to have oppositely disposed upper and lower surfaces, at least one of which is metal-coated. In this embodiment, the upper surface of the insulating dielectric substrate 10 is covered with a metal to form a patterned first conductive layer 12, and the lower surface may be covered with a metal to form another conductive layer, and the heat dissipating fins 14 may be disposed (see FIG. 3); A corresponding circuit pattern should be preset on the first conductive layer 12.

S120, at least one switch chip 20 and at least one diode chip 30 are disposed on the first conductive layer 12 to form an electrical connection with the first conductive layer 12.

Specifically, the switch transistor chip 20 is an IGBT, and the diode chip 30 is an FRD. The upper and lower surfaces of the chip have polar pins, and the switch chip 20 is attached to the upper surface of the insulating dielectric substrate 10 to form an electrical connection with the first conductive layer 12. Specifically, when the switch chip 20 and the diode chip 30 are attached to the circuit pattern of the first conductive layer 12 by soldering or crimping, the polarity pins of the lower surface are connected to the corresponding circuit pattern forming circuit to be led out. .

S130, an insulating layer 40 is disposed on the first insulating dielectric substrate 10, and the switch tube chip 20 and the diode chip 30 are covered.

In this embodiment, the insulating layer 40 is a prepreg, and the prepreg is insulated, and its thermal expansion coefficient needs to be matched with the thermal expansion coefficient of the switch chip 20 as much as possible.

S140, a second conductive layer 50 is disposed on the insulating layer 40. The second conductive layer 50 is preferably a conductive metal sheet. The second conductive layer 50 (conductive metal sheet or second insulating dielectric substrate), the prepreg, and the insulating dielectric substrate 10 provided with the switch tube chip 20 and the diode chip 30 are sequentially laminated and pressed, and the prepreg is filled with glue. The switch tube chip 20 and the diode chip 30 are covered.

Opening a through hole 42 penetrating the insulating layer 40 and the second conductive layer 50, and filling the through hole 42 with a conductive material, so that the second conductive layer 50 passes through the conductive material in the through hole 42 and The first conductive layer 12 is electrically connected, and the switch transistor chip 20 and the diode chip 30 are electrically connected.

Specifically, a polarity pin reaching the switch transistor chip 20 and the diode chip 30 and a via hole 42 reaching the first conductive layer 12 are formed on the second conductive layer 50 and the insulating layer 40 by laser technology, and the through hole is formed in the through hole The conductive material is filled in 42 to metalize the via hole 42. The second conductive layer 50 needs to be formed with a circuit pattern before or after lamination, and the polarity pins of the switch tube chip 20 and the upper surface of the diode chip 30 are connected to the corresponding circuit pattern forming circuits through the metalized via holes 42.

In a more specific embodiment, the step S120 further includes: further providing a lead-out terminal 60, wherein the one end of the lead-out terminal 60 is fixedly electrically connected to the first conductive layer 12, and the other end is outwardly extended. In other embodiments, when the patterned second conductive layer 50 can be disposed, the lead-out terminal is provided, and one end of the lead-out terminal 60 is fixedly electrically connected to the second conductive layer 50, and the other end is outwardly extended. The lead terminal includes a control terminal 62 and a power terminal 61, and the control terminal 62 and the power terminal 61 are respectively located on opposite sides of the power module. The low voltage control terminal is away from the high voltage power terminal, which reduces the electrical interference of the high voltage terminal to the low voltage terminal and improves the reliability of the control terminal.

Further, the method further includes the step of heating to cure the prepreg by heating to achieve insulation.

Further, the method further includes the step of disposing a heat sink disposed on a lower surface of the insulating dielectric substrate and/or an upper surface of the second conductive layer.

It can be seen that the above manufacturing method is that the power module is manufactured without encapsulation, and the production cost is saved; the chip is electrically connected through the metalized through hole 42 to reduce the volume of the module and facilitate the miniaturization of the module.

More specifically, the power module is manufactured by soldering the switch chip 20 and the diode chip 30, the control terminal 62, and the power terminal 61 to the first conductive layer 12 patterned on the insulating dielectric substrate 10 to form a prepreg of a corresponding thickness. (Insulating layer) 40, the second conductive layer 50 is laminated with the chip-attached insulating dielectric substrate 10, and the flow of the prepreg 40 is filled and covers the chip. The prepreg 40 is insulated, and the coefficient of thermal expansion needs to be as large as possible. The thermal expansion coefficient of the power device is matched. Matching means that the values of the two coefficients of thermal expansion are as close as possible or equal. First, the second conductive layer 50 of the laminated module is patterned, and the via hole 42 is formed by laser technology and metallized, so that the chip polarity pin and the corresponding lead terminal 60 are electrically connected. The via hole 42 is disposed as much as possible in order to ensure the reliability of the bonding between the metallized via 42 and the chip, so as to ensure the overcurrent capability of the circuit and improve the heat dissipation capability of the upper portion of the chip. The lower surface of the module (insulating dielectric substrate 10) is dissipated by the heat sink 70, and the upper surface of the module (second conductive layer 50) is coated with an insulating thermal conductive adhesive 80, and then connected to the other heat sink 70 to dissipate heat, thereby achieving double-sided heat dissipation and improving Cooling capacity. The two heat sinks 70 do not necessarily need to be disposed at the same time, and in the case where the heat dissipation condition can be satisfied, the heat sink 70 on the lower surface alone may constitute a single-sided heat dissipation.

The above description is only a preferred embodiment of the invention and is not intended to limit the invention in any way. While the invention has been described above in the preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above, or modify the equivalents of equivalent changes without departing from the scope of the technical solutions of the present invention. Example. Therefore, any simple modifications, equivalent changes, and modifications of the above embodiments may be made without departing from the spirit and scope of the invention.

Claims

A power module, comprising:

An insulating dielectric substrate having a patterned first conductive layer on an upper surface thereof;

At least one switch tube chip and at least one diode chip, the switch tube chip and the diode chip are attached on an upper surface of the insulating dielectric substrate to form an electrical connection with the first conductive layer;

An insulating layer covering the insulating dielectric substrate, the switching tube chip and the diode chip are covered, the insulating layer is provided with a through hole penetrating the upper and lower surfaces thereof, and the through hole is filled with a conductive substance ;

a patterned second conductive layer disposed on the insulating layer such that the second conductive layer is electrically connected to the first conductive layer through the conductive material, and the switch is turned by the conductive material The tube chip and the diode chip are electrically connected.
The power module of claim 1 wherein said insulating layer is a prepreg.
The power module according to claim 1 or 2, further comprising a lead terminal, one end of the lead terminal being fixedly electrically connected to the first conductive layer or the second conductive layer, and matching the through The conductive material in the hole is electrically connected to the corresponding polarity pin of the switch tube chip and the diode chip, and the other end of the lead terminal protrudes outward.
The power module according to claim 3, wherein the lead terminal comprises a control terminal and a power terminal, and the first conductive layer comprises a first circuit pattern and a second circuit pattern on opposite sides of the power module;

The polarity pins of the switch chip and the diode chip are respectively electrically connected to the first circuit pattern and the second circuit pattern through the conductive material in the corresponding through hole and the second conductive layer, respectively. The control terminal and the power terminal are fixedly electrically connected to the first circuit pattern and the second circuit pattern, respectively.
The power module of claim 4 wherein said first circuit pattern comprises an emitter pad and a collector pad, said power terminal comprising an emission soldered to the emitter pad and the collector pad, respectively Extreme power terminal and collector power terminal.
The power module according to any one of claims 1 to 5, further comprising a heat sink disposed on a lower surface of the insulating dielectric substrate and/or an upper surface of the second conductive layer .
The power module of claim 6 wherein said heat sink is a heat dissipating fin or a flat heat pipe.
The power module according to any one of claims 1 to 7, wherein the through hole further penetrates the second conductive layer.
A method of manufacturing a power module, comprising the steps of:

Providing an insulating dielectric substrate having a first conductive layer on the upper surface;

Providing at least one switch chip and at least one diode chip on the first conductive layer to form an electrical connection with the first conductive layer;

An insulating layer is disposed on the first insulating dielectric substrate to encapsulate the switch chip and the diode chip;

Providing a second conductive layer on the insulating layer, opening a through hole penetrating the insulating layer and the second conductive layer, and filling a conductive material in the through hole, so that the second conductive layer passes through the through hole A conductive substance in the hole is electrically connected to the first conductive layer, and the switch tube chip and the diode chip are electrically connected.
The method of manufacturing a power module according to claim 9, wherein when at least one of the switch tube chips and the at least one diode chip are disposed on the first conductive layer, a lead terminal is further provided to cause the lead terminal One end is fixedly electrically connected to the first conductive layer, and the other end is outwardly extended; or

When the second conductive layer is disposed, the lead-out terminal is disposed such that one end of the lead-out terminal is fixedly electrically connected to the second conductive layer, and the other end is outwardly extended.
The method of manufacturing a half-bridge power module according to claim 10, wherein the lead-out terminal comprises a control terminal and a power terminal, and the control terminal and the power terminal are respectively located on opposite sides of the power module.
The method of manufacturing a power module according to any one of claims 9 to 11, characterized in that the method further comprises the step of heating; wherein the insulating layer is a prepreg, and the prepreg is cured by heating to achieve insulation.
The method of manufacturing a power module according to any one of claims 9 to 12, further comprising a heat dissipator disposed on a lower surface of the insulating dielectric substrate and/or an upper surface of the second conductive layer.