CN112968027A

CN112968027A - Intelligent power module

Info

Publication number: CN112968027A
Application number: CN202110335012.XA
Authority: CN
Inventors: 王敏; 左安超; 谢荣才
Original assignee: Guangdong Huixin Semiconductor Co Ltd
Current assignee: Guangdong Huixin Semiconductor Co Ltd
Priority date: 2021-03-29
Filing date: 2021-03-29
Publication date: 2021-06-15

Abstract

The intelligent power module comprises a heat dissipation substrate, an insulating layer, a circuit wiring layer, an electronic element, a plurality of pins and a sealing layer, wherein the electronic element comprises a power device and a driving chip, and a heat insulation groove penetrating through the thickness of the heat dissipation substrate close to the driving chip is formed in the heat dissipation substrate, so that heat generated on the heat dissipation substrate due to the heating of the power device is well isolated from the driving chip, the heat is well prevented from being transmitted to the driving chip, the working temperature of the driving chip can be kept at a low temperature of about 25 ℃, the problem that a semiconductor element of the driving chip is unstable in working due to the overhigh temperature is well solved, and the reliability and the stability of the IPM are improved.

Description

Intelligent power module

Technical Field

The invention relates to an intelligent power module, and belongs to the technical field of power semiconductor devices.

Background

An intelligent Power module, i.e., ipm (intelligent Power module), is a Power driving product combining Power electronics and integrated circuit technology. The intelligent power module integrates a power switch device and a high-voltage driving circuit and is internally provided with fault detection circuits such as overvoltage, overcurrent and overheat. The conventional IPM module is characterized in that a driving circuit and a power switch device are arranged on the same substrate, and due to the fact that the substrate is high in heat conductivity coefficient, when the IPM module works, high temperature generated by the power switch device is transmitted to a driving chip of the driving circuit basically and rapidly, the driving chip works in a high-temperature environment, parameter deviation and control precision of a control IC are affected, and the service life of the driving chip is shortened due to the high temperature. Thereby affecting the operating life and operating reliability of the IPM module.

Disclosure of Invention

The technical problem to be solved by the invention is to solve the problem that the control precision and the service life of the conventional IPM module are influenced by overhigh working temperature of a driving chip caused by the heating of a power device because the power switch device and the driving chip are arranged on the same substrate.

Specifically, the present invention discloses an intelligent power module, comprising:

a heat-dissipating substrate made of a metal material;

a circuit wiring layer provided on the heat dissipation substrate, the circuit wiring layer being provided with a plurality of connection pads;

a plurality of electronic elements disposed on the bonding pads of the circuit wiring layer, the plurality of electronic elements including power devices and driving chips;

the pins are arranged on at least one side of the heat dissipation substrate;

the sealing layer at least wraps one surface of the heat dissipation substrate provided with the circuit element, and one end of each pin is exposed out of the sealing layer;

wherein, a heat insulation groove penetrating the thickness of the heat dissipation substrate is arranged on the heat dissipation substrate close to the driving chip.

Optionally, the heat insulation slots are multiple and are arranged close to the side edge of the driving chip.

Optionally, the four heat insulation grooves are long and are parallel to the side edges of the driving chip, and a connecting rib is arranged between the end portions, close to each other, of the two heat insulation grooves.

Optionally, the width of the insulation slot is 0.5mm to 2 mm.

Optionally, the smart power module further includes a plurality of bonding wires, and the bonding wires are connected between the plurality of electronic components, the circuit wiring layer, and the plurality of pins.

Optionally, a plurality of first driving bonding pads are disposed on the surface of the driving chip, a plurality of connection pads are disposed near the thermal insulation slot, and bonding wires are respectively connected between the plurality of connection pads and the first driving bonding pads.

Optionally, a second driving bonding pad is disposed on the ground of the driving chip, the second driving bonding pad is connected to the connection pad, and a routing line of the circuit wiring layer connected to the connection pad passes through the connection rib.

Optionally, the filler is angular, spherical, or a mixture of angular and spherical.

Optionally, the circuit composed of the circuit wiring layer and the electronic component disposed on the circuit wiring layer includes a driving circuit and an inverter circuit, wherein the inverter circuit includes 6 switching tubes of upper and lower bridge arms, the driving circuit includes a driving chip, and the driving chip is provided with at least one of an over-temperature protection switching circuit, an under-voltage protection circuit, an over-current protection circuit, and an over-voltage protection circuit.

Drawings

FIG. 1 is a top view of an IPM module in accordance with an embodiment of the invention;

FIG. 2 is a cross-sectional view taken along the line X-X in FIG. 1;

FIG. 3 is a top view of an IPM module in accordance with an embodiment of the invention with the sealing layer removed;

FIG. 4 is a top view of an IPM module in accordance with another embodiment of the invention with the sealing layer removed;

FIG. 5 is a circuit diagram of a driver chip of an IPM module according to an embodiment of the present invention;

fig. 6 is a simplified schematic circuit diagram of an IPM module according to an embodiment of the present invention.

Reference numerals:

the packaging structure comprises a sealing layer 100, a lead 101, a heat dissipation substrate 102, an insulating layer 103, a driving chip 104, a bonding wire 105, an IGBT106, a heat insulation groove 107, a connection pad 108, a free wheel diode 109, a wire 110, a connection rib 111, a circuit wiring layer 112 and a first driving bonding pad 113.

Detailed Description

It is to be noted that the embodiments and features of the embodiments may be combined with each other without conflict in structure or function. The present invention will be described in detail below with reference to examples.

The present invention provides an intelligent power module, i.e. an IPM module, as shown in fig. 1 to 4, including a heat dissipation substrate 102, a circuit wiring layer 112, a plurality of electronic components, a plurality of pins 101, and a sealing layer 100.

The heat dissipation substrate 102 is made of a metal material, and includes an upper mounting surface and a lower heat dissipation surface, and may be a rectangular plate made of aluminum such as 1100, 5052, and the like. Alternatively, the heat dissipating substrate 102 may be a non-metal substrate, and the main body thereof is made of an insulating material with good thermal conductivity, such as glass, ceramic, and the like.

For the heat dissipation substrate 102 of a metal material, it is also necessary to provide the insulating layer 103 to provide the circuit wiring layer 112 on the insulating layer 103 to achieve electrical isolation between the circuit wiring layer 112 and the heat dissipation substrate 102. The insulating layer 103 is formed to cover at least one surface of the heat dissipating substrate 102, and is made of a resin material such as epoxy resin, and a filler such as alumina and aluminum carbide is filled inside the resin material to improve thermal conductivity. In order to increase the thermal conductivity, the shape of these fillers may be angular, and in order to avoid the risk of the fillers damaging the contact surfaces of the electronic components arranged on the surface thereof, the fillers may be spherical or a mixture of angular and spherical. The heat dissipation substrate 102 in fig. 1 to 3 is made of metal. For the non-metal substrate, the heat dissipation substrate 102 made of metal material does not include the insulating layer 103, and the body is made of insulating material. The circuit wiring layer 112 may be formed by etching copper foil or by printing a paste-like conductive medium, which may be a conductive material such as graphene, solder paste, or silver paste. A wiring 110 of a circuit is formed on the circuit wiring layer 112, and a plurality of connection pads 108 for connecting the wiring 110 are provided for mounting an electronic component and the pin 101. The pins 101 are electrically fixed to the connection pads 108 on one edge of the circuit board, and have a function of inputting and outputting signals to and from an external circuit connected to the IPM module, and in this embodiment, as shown in fig. 1, a plurality of pins 101 are led out from one side of the heat dissipation substrate 102, but may be led out from the opposite sides of the heat dissipation substrate 102 in other embodiments. The lead 101 is generally made of copper or other metal, a nickel-tin alloy layer is formed on the copper surface by chemical plating and electroplating, the thickness of the alloy layer is generally 5 μm, and the copper can be protected from corrosion and oxidation by the plating layer, and the solderability can be improved. The sealing layer 100 may be formed of resin, and may be molded using thermosetting resin by a transfer molding method or thermoplastic resin by an injection molding method. The sealing layer 100 has two packaging structures, one is that the sealing layer 100 covers the upper and lower surfaces of the heat dissipation substrate 102 and covers the electronic elements arranged on the heat dissipation substrate 102, and also covers the pins 101 arranged at one end of the heat dissipation substrate 102, which is a full-covering mode of the sealing layer 100; in another packaging method, the sealing layer 100 covers the upper surface of the heat dissipating substrate 102, i.e., covers the heat dissipating substrate 102, the electronic component and the leads 101 disposed at one end of the heat dissipating substrate 102, and the lower surface of the heat dissipating substrate 102, i.e., the heat dissipating surface, is exposed out of the sealing layer 100, thereby forming a half-covered method of the sealing layer 100. Fig. 2 shows a full coating mode of the sealing layer 100.

Electronic components are disposed on the connection pads 108 of the circuit wiring layer 112, and the electronic components include a power device and the driver chip 104, wherein the power device includes a switching Transistor such as an IGBT106(Insulated Gate Bipolar Transistor) or a MOS Transistor (metal oxide semiconductor), and the like, and also includes a freewheeling diode 109, which consumes a large amount of power and generates a large amount of heat, while the driver chip 104 consumes a much smaller amount of power and generates a very low amount of heat during operation, and the driver chip 104 includes a plurality of micro semiconductor devices therein, and thus the temperature of the driver chip 104 is much lower than that of the power device. In the working process of the power device, a large amount of heat generated by the power device is transmitted to the driving chip 104 through the heat dissipation substrate 102, so that the temperature of the power device rises suddenly, for example, the temperature can reach above 60 ℃, and in order to solve the problem, as shown in fig. 2 to 4, a heat insulation groove 107 penetrating through the thickness of the heat dissipation substrate 102 close to the driving chip 104 is formed. The heat insulation groove 107 is preferably disposed near the periphery of the driving chip 104, and the width of the heat insulation groove 107 is convenient for manufacturing, for example, the width can be selected to be 0.5mm to 3mm, and the heat insulation groove can be manufactured by mechanical processing, laser etching or chemical etching. A connecting rib 111 is provided between the ends of the heat insulating groove 107 to connect the region of the heat dissipating substrate 102 where the driving chip 104 is mounted with the other region of the heat dissipating substrate 102. The connecting ribs 111 are preferably integrally formed with the heat dissipating substrate 102 to facilitate manufacturing. The heat insulation grooves 107 are arranged on the periphery of the driving chip 104, so that heat generated on the heat dissipation substrate 102 due to the heating of the power device is better isolated from the driving chip 104, the heat is better prevented from being transmitted to the driving chip 104, the working temperature of the driving chip 104 can be kept at a lower temperature, such as about 25 ℃, the problem that the semiconductor element of the driving chip 104 is unstable due to overhigh temperature is well solved, and the reliability and stability of the IPM work are improved. In addition, in the relevant specification of the IPM module for the driver chip 104, each parameter is obtained by testing at room temperature of 25 ℃, so that the closer the working temperature of the driver chip 104 is to room temperature, the more beneficial an engineer designs the relevant circuit of the IPM module with reference to the parameter of the specification, and the design requirement of the engineer is reduced.

The heat insulation groove 107 may be a single groove, and is disposed around the periphery of the driving chip 104, as shown in fig. 4, and has a ring shape, and the width of the connecting rib 111 may be about 2mm to 4mm in order to ensure that the heat dissipation substrate 102 portion on which the driving chip 104 is mounted is reliably connected with other portions.

In some embodiments of the present invention, the thermal insulation slot 107 may be multiple and is disposed near the side of the driver chip 104. When a plurality of heat insulation grooves 107 are arranged, the number of the connecting ribs 111 is at least two, for example, two heat insulation grooves 107 are annularly arranged around the driving chip 104, and the number of the connecting ribs 111 is two, compared with the single connecting rib 111 in the above scheme, the width of the connecting rib 111 can be reduced, for example, set at 1mm to 2mm, so that the heat transfer on the heat dissipation substrate 102 through the connecting ribs 111 is further reduced while the heat dissipation substrate 102 part on which the driving chip 104 is mounted is reliably connected with other parts. The heat transferred to the driver chip 104 is lower, and thus the temperature rise of the driver chip 104 is further improved.

Further, as shown in fig. 3, the heat insulation grooves 107 are four and elongated and are respectively disposed in parallel with the side edges of the driving chip 104, and a connection rib 111 is disposed between the end portions of the two heat insulation grooves 107 close to each other, thereby forming 4 connection ribs 111. The length of the thermal insulation slot 107 is close to the length of the side edge of the driving chip 104, and the width of the four connecting ribs 111 can be further reduced, for example, set to be 0.5mm to 1.5mm, so as to further prevent and reduce the heat transfer on the heat dissipation substrate 102 through the connecting ribs 111.

In some embodiments of the present invention, as shown in fig. 2 to 4, a plurality of bonding wires 105 are further included, and the bonding wires 105 are connected between the plurality of electronic components, the circuit wiring layer 112, and the plurality of pins 101. The electronic components are the IGBT106, the driver chip 104, the freewheeling diode 109, and others such as resistors, capacitors, etc. mentioned in the above embodiments. The bond wires 105 are typically gold wires, copper wires, hybrid gold-copper wires, 38um, or thin aluminum wires below 38 um. Specifically, the bonding wire 105 may connect between the electronic component and the electronic component, may connect between the electronic component and the circuit wiring layer 112, may connect between the electronic component and the lead 1013, and the like, thereby forming a circuit connection of the entire IPM module.

In some embodiments of the present invention, as shown in fig. 2 to 4, a plurality of first driving bonding pads 113 are disposed on a surface of the driving chip 104, a plurality of connection pads 108 are disposed near the thermal insulation groove 107, one end of the bonding wire 105 is connected to the first driving bonding pads 113, and the bonding wires 105 are respectively connected between the plurality of connection pads 108 and the driving bonding pads 113. For a high voltage driver chip 104(HVIC), the surface has at least six driver bond pads 113, namely, low voltage region power VDD, low voltage region ground VSS, high voltage region power VB, high voltage region ground VS, input IN and output HO, and the back surface of the high voltage driver chip 104, i.e., the surface mounted with the connection pads 108, is not metallized. For the low voltage driver chip 104, there are at least four driver bonding pads 113 on its surface, which are low voltage region power VDD, low voltage region ground VSS, input IN and output HO, respectively, and the back surface of the high voltage driver chip 104, i.e. the surface mounted with the connection pads 108, is not metallized. A plurality of connecting pads 108 are arranged near the heat insulation groove 107, so that the driving bonding pads 113 and the connecting pads 108 are connected through the bonding wires 105, and the lengths of the bonding wires 105 are effectively shortened while circuit connection is realized.

In some embodiments of the present invention, the ground of the driving chip 104 is provided with a second driving bonding pad (not shown in the figure), the second driving bonding pad is connected with the connection pad 108, and the trace 110 of the circuit wiring layer 112 of the connection pad passes through the connection rib 111. In contrast to the previous embodiment, in which the back surface of the driving chip 104 is not metallized, the back surface of the driving chip in this embodiment needs to be metallized to form a second driving bonding pad, which is used as a connection terminal of the driving chip 104, such as a low voltage region ground VSS, etc., and is electrically connected and fixed with the connection pad 108 in the circuit wiring layer 112 by soldering, and the ground trace of the circuit wiring layer 112 inside the thermal insulation groove 107 is electrically connected with the ground wire in the circuit wiring layer 112 outside the thermal insulation groove 107 through the connection rib 111. The first driving bonding pad 113 for the low voltage ground VSS disposed at the surface of the driving chip 104 can be eliminated, and the bonding wire 105 can be reduced. Through the large-area grounding routing of the bottom of the driving chip 104 relative to the bonding wire 105, the grounding is more reliable, and the overcurrent on the ground wire can be effectively improved due to the increase of the area of the ground wire.

In some embodiments of the present invention, as shown in fig. 3 to fig. 6, a circuit composed of the circuit wiring layer 112 and the electronic component disposed on the circuit wiring layer 112 includes a driving circuit and an inverter circuit, wherein the inverter circuit includes 6 switching tubes of upper and lower bridge arms, the driving circuit includes the driving chip 104, and the driving chip 104 is provided with at least one of an over-temperature protection switching circuit, an under-voltage protection circuit, an over-current protection circuit, and an over-voltage protection circuit. Wherein the driving circuit mainly comprises a driving chip 104, the inverter circuit mainly comprises 3 sets of inverter units of upper and lower bridge arms, each inverter unit comprises two three-level transistors, which are IGBTs 106 in fig. 6, and can also be MOS transistors, wherein a triode transistor 202 and a triode transistor 205 are combined into one set, a triode transistor 203 and a triode transistor 206 are combined into one set, a triode transistor 204 and a triode transistor 207 are combined into one set, each set of two triode transistors is divided into an upper bridge arm and a lower bridge arm, wherein the triode transistor 202 is an upper bridge arm, the triode transistor 205 is a lower bridge arm, the triode transistor 203 is an upper bridge arm, the triode transistor 206 is a lower bridge arm, the triode transistor 204 is an upper bridge arm, the triode transistor 207 is a lower bridge arm, a drain of the triode transistor 202 of the upper bridge arm is connected with a high voltage input end P of the module, a source of the triode transistor 202 of the, the source of the triode transistor 205 of the lower bridge arm is connected with the terminal of the module external pin 101UN, the gates of the two triode transistors are both connected with the driving chip 104, the source of the triode transistor 203 of the upper bridge arm is connected with the drain of the triode transistor 205 of the lower bridge arm, the source of the triode transistor 206 of the lower bridge arm is connected with the terminal of the module external pin 101VN, the gates of the two triode transistors are both connected with the driving chip 104,，the source of the three-pole transistor 204 of the upper bridge arm is connected with the drain of the three-pole transistor 207 of the lower bridge arm, the source of the three-pole transistor 207 of the lower bridge arm is connected with the WN end of the module outer pin 101, and the gates of the two three-pole transistors are connected with the control chip. FIG. 5 is a circuit diagram of the driving chip 104, except that the driving chip includes driving circuits for driving the upper and lower bridge arm switch tubes, i.e. a high-voltage side driving circuit for driving the upper bridge arm switch tube and a driving circuit for driving the lower bridge arm switch tubeThe low-voltage side driving circuit further comprises an over-temperature protection switch, an under-voltage protection circuit, an over-current protection circuit and an over-voltage protection circuit, and the control precision of the circuits is high so as to improve the control precision of the driving chip 104 and avoid the influence of over-high temperature on the parameters of the driving chip 104.

In some embodiments of the present invention, as shown in fig. 3 and 4, six switching tubes of the inverter circuit, i.e., the IGBTs 106, are divided into two groups of upper and lower bridge arms, wherein three switching tubes of the upper bridge arm are arranged above the circuit wiring layer 112 in parallel, three switching tubes of the lower bridge arm are arranged below the circuit wiring layer 112 in parallel, the switching tubes are arranged close to each other, the driving chip 104 serving as the driving circuit is arranged on the other side of the circuit wiring layer 112, e.g., the right side in fig. 3 and 4, and is further away from the six switching tubes, the driving chip 104 and the six switching tubes are connected by the wires 110, because the inverter circuit operates in a strong current region (about 300V dc power supply), and a part of the driving chip 104 operates in a weak current region, and the input control signal is a weak current signal, therefore, by arranging the driving chip 104 and the switching tubes far away, interference caused by switching between the high voltage of the high-voltage power and the high-speed switching tubes in the strong current region on the weak current The circuit generated interference causes unstable operation, thereby being helpful to prompt the stability and reliability of the operation of the whole IPM module.

Further, the IPM module further includes a PFC circuit, as shown in fig. 3 and 4, four IGBT106 tubes are disposed on the left side of the circuit wiring layer 112 to form a full-bridge PFC circuit, so that the PFC circuit is integrated in the IPM module, thereby expanding the application of the IPM module.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A smart power module comprising:

a heat-dissipating substrate made of a metal material;

a circuit wiring layer disposed on the heat dissipation substrate, the circuit wiring layer being provided with a plurality of connection pads;

a plurality of electronic elements disposed on the pads of the circuit wiring layer, the plurality of electronic elements including power devices and driving chips;

a plurality of pins disposed on at least one side of the heat-dissipating substrate;

the sealing layer at least wraps one surface of the heat dissipation substrate provided with the circuit element, and one end of the pin is exposed out of the sealing layer;

wherein the heat dissipation substrate close to the driving chip is provided with a heat insulation groove penetrating through the thickness of the heat dissipation substrate.

2. The smart power module of claim 1, wherein the heat insulation slot is formed in a plurality of slots adjacent to a side of the driving chip.

3. The intelligent power module as claimed in claim 2, wherein the four heat-insulating slots are elongated and are respectively disposed parallel to the side edges of the driving chip, and a connecting rib is disposed between the adjacent ends of the two heat-insulating slots.

4. The smart power module of claim 2, wherein the width of the thermal isolation slot is 0.5mm to 2 mm.

5. The smart power module of claim 1 further comprising a plurality of bond wires connected between the plurality of electronic components, the circuit routing layer, and the plurality of pins.

6. The smart power module as claimed in claim 5, wherein a plurality of first driving bonding pads are disposed on a surface of the driving chip, a plurality of connecting pads are disposed adjacent to the thermal insulation slot, and the bonding wires are respectively connected between the connecting pads and the first driving bonding pads.

7. The smart power module according to claim 6, wherein a ground of the driving chip is provided with a second driving bonding pad, the second driving bonding pad is connected to the connection pad, and a trace of the circuit wiring layer connected to the connection pad passes through the connection rib.

8. The smart power module of claim 1 wherein the insulating layer is made of a resin material filled with a filler of alumina and aluminum carbide.

9. The smart power module of claim 8 wherein the filler is angular, spherical, or a mixture of angular and spherical.

10. The smart power module as claimed in claim 1, wherein the circuit composed of the circuit wiring layer and the electronic components disposed on the circuit wiring layer includes a driving circuit and an inverter circuit, wherein the inverter circuit includes 6 switching transistors of upper and lower bridge arms, the driving circuit includes the driving chip, and the driving chip is provided with at least one of an over-temperature protection switching circuit, an under-voltage protection circuit, an over-current protection circuit, and an over-voltage protection circuit.