CN114388490A - Packaging structure of intelligent power module and packaging method thereof - Google Patents

Abstract

The invention provides a packaging structure of an intelligent power module and a packaging method thereof. By arranging the driving chip and the power chip on the first substrate and the second substrate respectively, and arranging the first substrate and the second substrate to face each other, the driving chip and the power chip can be vertically aligned in the thickness direction. The straight arrangement greatly reduces the mounting area of the module and realizes the miniaturization of the module. In addition, for the first substrate and the second substrate arranged facing each other, it is convenient to expose the back surface of the first substrate on which the power chip is arranged, so as to improve the heat dissipation effect.

Description

Packaging structure of intelligent power module and packaging method thereof

technical field

The invention relates to the technical field of semiconductors, in particular to a packaging structure of an intelligent power module and a packaging method thereof.

Background technique

Intelligent Power Module (IPM, Intelligent Power Module) integrates drive circuits and power devices, adapting to the development direction of today's power devices, which tend to be modular, composite and power integration, especially in power electronics. Wide range of applications.

At present, the common package types for intelligent power modules generally include DIP (dual in-line package technology), SOP (small outline package) and QFN (square flat no lead package). However, for DIP and SOP type packages, it needs to set longer pins, which will occupy a larger area on the system circuit board, which is not conducive to the miniaturization of systems and equipment; and, for QFN type packages, its No structure with exposed metal is provided, which makes its heat dissipation effect poor, and is only suitable for low-power applications.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a package structure of an intelligent power module, so as to solve the problems of large size and poor heat dissipation effect of the existing package structure of an intelligent power module.

In order to solve the above technical problems, the present invention provides a package structure of an intelligent power module, comprising: a first substrate provided with a power chip, a second substrate provided with a driver chip, and a combination of the first substrate and the second substrate. The substrate encapsulates the fixed plastic encapsulation layer. Wherein, the side of the first substrate with the power chip faces the side of the second substrate with the driver chip, and the side of the first substrate away from the power chip is exposed from the plastic sealing layer.

Optionally, the first substrate is a metal-clad ceramic substrate, and the metal layer on the surface of the metal-clad ceramic substrate facing away from the power chip is exposed from the plastic sealing layer.

Optionally, a plurality of lead-out terminals penetrating through the second substrate are formed in the second substrate, and the lead-out terminals protrude from a side of the second substrate away from the driving chip.

Optionally, the plastic encapsulation layer covers a side of the second substrate away from the driving chip, and exposes the lead terminals from the plastic encapsulation layer.

Optionally, the second substrate is a printed circuit board, and the driving chip is flip-chip mounted on the printed circuit board, and is electrically connected to a circuit in the printed circuit board.

Optionally, a connecting column is further provided between the first substrate and the second substrate, and the first substrate and the second substrate are electrically connected through the connecting column.

The present invention also provides a packaging method for an intelligent power module, comprising: arranging a power chip on a first substrate, and arranging a driving chip on a second substrate; The side of the second substrate with the driving chip is injection-molded and encapsulated to form a plastic encapsulation layer, and the side of the first substrate facing away from the power chip is exposed from the plastic encapsulation layer.

Optionally, the second substrate is a printed circuit board, and the driving chip is flip-chip mounted on the printed circuit board, and is electrically connected to a circuit in the printed circuit board.

Optionally, a plurality of lead-out terminals penetrating through the second substrate are formed in the second substrate; after injection molding and encapsulation, the lead-out terminals are exposed from the plastic encapsulation layer.

Optionally, before performing injection molding and encapsulation, a connection post is arranged on the first substrate or the second substrate, and the first substrate and the second substrate are assembled, so that the two parts of the connection post are assembled. The end is fixedly connected to the first substrate and the second substrate.

In the packaging structure of the smart power module and the packaging method thereof provided by the present invention, the driver chip and the power chip are respectively arranged on the first substrate and the second substrate, and the first substrate and the second substrate face each other The arrangement enables the driver chip and the power chip to be vertically arranged in the thickness direction, which greatly reduces the mounting area of the module and realizes the miniaturization of the module. In addition, in the case of reducing the area of the module, it is also allowed to expose a larger area of the first substrate provided with the power chip, so that the heat dissipation effect of the module can be further improved to meet the requirements of the intelligent power module in high-power applications. need.

Description of drawings

Figure 1 is a package structure of an intelligent power module.

FIG. 2 is a package structure of an intelligent power module in an embodiment of the present invention.

FIG. 3 is a schematic flowchart of a packaging method of an intelligent power module according to an embodiment of the present invention.

Among them, the reference numerals are as follows:

100 - the first substrate;

110 - ceramic layer;

120 - metal layer;

10a/100a-power chip;

200 - the second substrate;

20a/200a- driver chip;

30/300-plastic layer;

400-lead terminal;

410 - conductive column;

420 - contact pad;

500 - connecting column.

Detailed ways

As described in the background art, the packaging method of the intelligent power module in the traditional process has the problems that the packaged structure size is large and the heat dissipation effect is not good.

In this regard, a package structure of an intelligent power module is proposed, such as the package structure of an intelligent power module shown in FIG. 1, which specifically mounts the power chip 10a on a substrate, and connects the substrate and the frame , and mount the driver chip 20a on the frame, the power chip 10a is electrically connected with the driver chip 20a arranged side by side with the bonding wire. And, the substrate, the power chip 10a, the driving chip 20a and the frame are packaged and fixed by the plastic packaging layer 30, wherein the backside of the substrate with the power chip 10a is exposed from the plastic packaging layer 30 for heat dissipation, and the pins of the frame are also It extends from the plastic encapsulation layer 30 and is used for electrical connection with external circuits.

In the smart power module shown in FIG. 1 , the exposed surface of the substrate is used to achieve the effect of heat dissipation. However, the driver chip 20a and the power chip 10a arranged side by side still need to occupy a large area, resulting in a relatively large volume of the module. miniaturization of the module.

In order to further optimize the intelligent power module, the present invention provides a package structure of the intelligent power module, wherein the power chip and the driving chip are respectively arranged on the first substrate and the second substrate, so that the first substrate and the second substrate can be assembled together. The substrates are arranged in a face-to-face manner, so that the driving chips and the power chips can be arranged vertically in the thickness direction, which effectively reduces the volume of the module. In addition, for the first substrate and the second substrate arranged face to face, it is also beneficial to expose the back surface of the first substrate provided with the power chip, so as to improve the heat dissipation effect.

The encapsulation structure and encapsulation method of the intelligent power module proposed by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are all in a very simplified form and in inaccurate scales, and are only used to facilitate and clearly assist the purpose of explaining the embodiments of the present invention. As well as relative terms such as "above," "below," "top," "bottom," "over," and "under" as shown in the figures may be used to describe the relationship of various elements to each other. These relative terms are intended to encompass different orientations of the elements in addition to the orientation depicted in the figures. For example, if the device is turned over with respect to the view in the figures, elements described as "above" another element, for example, would now be below the element.

FIG. 2 is a schematic structural diagram of an intelligent power module according to an embodiment of the present invention. As shown in FIG. 2 , the intelligent power module includes: a first substrate 100 provided with a power chip 100 a and a second substrate provided with a driving chip 200 a 200 , and a plastic encapsulation layer 300 for encapsulating and fixing the first substrate 100 and the second substrate 200 . Wherein, the power chip 100a may be, for example, an IGBT chip, a FRD chip, or a MOSFET chip, etc., and the driving chip 200a may be, for example, an MCU control chip or the like.

Further, the side of the first substrate 100 with the power chip 100 a faces the side of the second substrate 200 with the driving chip 200 a. That is, the power chip 100a and the driving chip 200a are plastic-sealed between the first substrate 100 and the second substrate 200, so that the power chip 100a and the driving chip 200a are arranged in a vertical direction. Compared with the horizontal arrangement of the driver chip and the power chip in the traditional process, the vertical arrangement of the power chip 100a and the driver chip 200a along the thickness direction in this embodiment will help reduce the size of the entire power module and realize the module of miniaturization.

Continuing to refer to FIG. 2 , the side of the first substrate 100 facing away from the power chip 100 a is exposed from the plastic encapsulation layer 300 and used as the main heat dissipation surface of the module, so that the heat generated by the power chip 100 a during operation It can be quickly diffused out through the back surface of the first substrate 100 . It should be noted that in this embodiment, by arranging the power chip 100a and the driving chip 200a in the vertical direction, the mounting area of the module is greatly reduced, and on this basis, it is also beneficial to further increase the first substrate The area of 100, correspondingly expands the area of the heat dissipation surface exposed by the module and improves the heat dissipation effect. That is, the package structure of the intelligent power module provided by this embodiment, compared with the traditional package structure, not only can reduce the volume of the module, but also further improves the heat dissipation effect, so that it is more suitable for high-power applications.

In a specific solution, the first substrate 100 may be a metal-clad ceramic substrate, and the metal layer on the surface of the metal-clad ceramic substrate facing away from the power chip may be exposed from the plastic sealing layer 300 . Since the metal-clad ceramic substrate has the characteristics of high thermal conductivity and low thermal resistance, it can achieve efficient heat dissipation, and a variety of circuit patterns can be prepared on the surface of the metal-clad ceramic substrate. The power chip 100a connected to the substrate That is, electrical communication can be realized with other chips through the lines on the surface of the metal-clad ceramic substrate.

In this embodiment, the first substrate 100 specifically includes a ceramic layer 110 and a metal layer 120 covering two opposite surfaces of the ceramic layer 110 . Wherein, the metal layer on the surface of the first substrate 100 facing away from the power chip 100 a is exposed from the plastic sealing layer 300 . Also, the metal layer on the surface of the first substrate 100 on which the power chip 100 a is disposed may be a patterned metal circuit, and the power chip 100 a is electrically connected to the metal circuit on the first substrate 100 . In a specific application, the material of the ceramic layer 110 includes, for example, at least one of aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN) and silicon nitride (Si ₃ N ₄ ), and the metal layer 120 includes, for example, at least one material of copper (Cu) and aluminum (Al).

Further, the power chip 100a may be disposed on the first substrate 100 by welding or sintering, for example. Also, a surface of the power chip 100a on one side away from the first substrate may be electrically connected to metal lines on the first substrate 100 through bonding wires.

Continuing to refer to FIG. 2 , in this embodiment, the lead-out terminal 400 of the module can be disposed on the second substrate 200 and the lead-out terminal 400 is exposed from the plastic encapsulation layer 300 for electrical connection with external circuits connect. Optionally, the side of the second substrate 200 facing away from the driving chip 200 a is also covered with the plastic encapsulation layer 300 , and the lead-out terminals 400 are exposed from the plastic encapsulation layer 300 .

The lead-out terminal 400 includes conductive pillars 410 and contact pads 420 penetrating through the second substrate 200 , and the conductive pillars 410 extend through the second substrate 200 to the surface of the second substrate 200 away from the first substrate 100 . , the contact pads 420 are formed on the surface of the second substrate 200 away from the first substrate 100 and cover the ends of the conductive pillars 410 . In this embodiment, the lead-out terminal 400 can be led out to the exposed surface of the second substrate 200 by penetrating the second substrate 200 , so that the length of the lead-out terminal 400 is shorter, which is beneficial to reduce the signal intensity. interference and improve the performance of the module.

Further, the second substrate 200 can be, for example, a printed circuit board (PCB), which can realize a more complex logic connection circuit in a smaller volume, and the driving chip 200a is electrically connected to the printed circuit board. lines in the circuit board. Specifically, the driver chip 200a can be flip-chipped on the printed circuit board, for example (for example, the driver chip 200a can be disposed on the second substrate 200 by means of adhesion or welding), so that the driver The chip 200a can be directly electrically connected to the circuit in the printed circuit. Therefore, the signal transmission of the driving chip 200a can be directly realized through the internal wiring of the printed circuit board, which effectively improves the problem of interference of the driving signal and improves the reliability of the module. stability. In addition, there is no need to perform external wire bonding on the driver chip 200a, the step of wire bonding is omitted, the process is saved, the cost can be reduced, and further size reduction is facilitated (no space for wire bonding is required).

In a further solution, the first substrate 100 and the second substrate 200 are also electrically connected to each other, so that the first substrate 100 and the second substrate can be connected between the driving chip 200a and the power chip 100a. 200 for electrical connection.

Referring specifically to FIG. 2 , in this embodiment, a connection post 500 is further provided between the first substrate 100 and the second substrate 200 , and the connection post 500 may be formed of a conductive material (the connection post The material of 500 includes, for example, copper, aluminum, gold, etc.), and the first substrate 100 and the second substrate 200 are electrically connected through the connection posts 500 . Wherein, the connection posts 500 may be disposed at the edge positions of the first substrate 100 and the second substrate 200 .

Specifically, a conductive connection pad may be provided on the surface of the second substrate 200 facing the first substrate 100 , and one end of the connection post 500 is in contact with the conductive connection pad of the second substrate 200 . The other end of the connection post 500 abuts against the metal layer 120 of the first substrate 100 . The materials of the conductive connection pads may be the same as the materials of the conductive pillars 500 , or may be different.

Continuing to refer to FIG. 2 , the plurality of lead-out terminals 400 include a first lead-out terminal that is electrically connected to the connection post 500 . In this embodiment, one end of the conductive post 410 in the first lead-out terminal close to the connection post 500 is connected to one surface of the connection pad, and the connection post 500 abuts against the other surface of the connection pad. In addition, the plurality of lead-out terminals 400 further include a second lead-out terminal electrically connected to the driving chip 200a, and the ends of the conductive pillars 410 in the second lead-out terminal are electrically connected to the driving chip 200a.

In this embodiment, the first substrate 100 , the second substrate 200 and the connecting post 500 are fixed by the plastic sealing layer 300 , wherein the plastic sealing material of the plastic sealing layer 300 includes, for example, a resin material or the like. Specifically, the plastic encapsulation layer 300 encapsulates the first substrate 100 , the second substrate 200 and the sidewalls of the connecting posts 500 , and makes the first substrate 100 face away from the second substrate 200 The surface of the second substrate 200 is exposed from the plastic encapsulation layer 300 to form the main heat dissipation surface, and the lead terminals 400 on the second substrate 200 are also exposed from the plastic encapsulation layer 300 to lead out the electrodes of the module and communicate with the outside circuit connection.

It can be seen that, in the smart power module provided in this embodiment, the main heat dissipation path is diffused from the power chip 100 a to the outside of the first substrate 100 , and the main electrical path is further transmitted by the first substrate 100 and the second substrate 200 . The lead-out terminal 400 to the outside of the second substrate 200 realizes that the heat dissipation path and the electrical path flow in opposite directions, so that the two travel through different paths, with less mutual interference.

In addition, in this embodiment, by arranging the first substrate 100 and the second substrate 200 opposite to each other, the current flow path on the first substrate 100 and the current flow path on the second substrate 200 may be opposite or substantially opposite or in a trend. On the contrary, the circuit on the first substrate 100 and the current path on the second substrate 200 are made to have mutual inductance, so as to reduce the stray inductance and help to cancel the self-inductance. Specifically, for the printed circuit board, the internal circuit arrangement has greater flexibility, so the circuit in the printed circuit board can be adjusted to realize the current flow path on the first substrate 100 and the second circuit The current flow paths on the substrate 200 are opposite or substantially opposite or tend to be opposite.

Based on the packaging structure of the smart power module as described above, the packaging method of the smart power module will be described below. Specifically, the packaging method includes: arranging a power chip on a first substrate, and arranging a driving chip on a second substrate; then, orienting the side of the first substrate with the power chip toward the second substrate with the driving chip One side is injection-molded and encapsulated to form a plastic encapsulation layer, and the side of the first substrate facing away from the power chip is exposed from the plastic encapsulation layer.

The encapsulation method in this embodiment is illustrated below with reference to FIG. 2 and FIG. 3 . 3 is a schematic flowchart of a packaging method of an intelligent power module according to an embodiment of the present invention.

First, the power chip 100 a is provided on the first substrate 100 . The first substrate 100 is, for example, a metal-clad ceramic substrate, and the power chip 100a may be disposed on the first substrate 100 by bonding, welding or sintering.

And, the driver chip 200a is disposed on the second substrate 200, wherein the second substrate 200 can be, for example, a printed circuit board (PCB), and the driver chip 200a can be disposed on the second substrate by means of adhesion or welding. 200 on. In this embodiment, the driver chip 200a is flip-chipped on the second substrate 200, so that the driver chip 200a can be directly electrically connected to the circuit in the printed circuit, and then can directly pass through the inside of the printed circuit board. Signal transmission can be realized by using the same wiring, which effectively improves the problem that the driving signal is disturbed, and also does not need to perform external wiring on the driving chip 200a, which is beneficial to save the process and reduce the cost.

Further, lead-out terminals 400 are formed on the second substrate 200 , and the lead-out terminals 400 are exposed on the surface of the second substrate 200 away from the driving chip 200 a. Specifically, the method for forming the lead-out terminal 400 includes, for example: forming a through hole in the second substrate 200 , filling the through hole with a conductive material to form a conductive column 410 ; and, on the second substrate 200 facing away from the The surface of the driving chip 200 a is patterned by a film layer to form contact pads 420 , and the contact pads 420 cover the ends of the conductive pillars 410 .

Next, connecting posts 500 are disposed on the first substrate 100 or the second substrate 200 , and the connecting posts 500 can be soldered to the first substrate 100 or the second substrate 200 , for example. Specifically, the connection post 500 is disposed on the surface of the first substrate 100 having the power chip 100a; or, the connection post 500 is disposed on the surface of the second substrate 200 having the driving chip 200a. In this embodiment, the connection post 500 is welded on the first substrate 100 as an example for illustration; however, in other embodiments, the connection post 500 may also be preferentially welded on the second substrate 200 .

The connection post 500 can not only be used to preliminarily define the distance between the first substrate 100 and the second substrate 200 when assembling the first substrate 100 and the second substrate 200 , but also be used to realize the first substrate 100 and the second substrate 200 electrical connection between them.

Next, the first substrate 100 and the second substrate 200 are assembled. Specifically, the first substrate 100 having the power chip 100a is assembled with the side facing the second substrate 200 having the driving chip 200a, and the connection post 500 is in contact with the substrate not provided with the connection post during assembly. On the surface, the two ends of the connecting post 500 can be fixedly connected to the first substrate 100 and the second substrate 200 by means of crimping or welding.

Next, injection molding is performed to form a plastic encapsulation layer 300 , and the side of the first substrate 100 facing away from the power chip 100 a is exposed from the plastic encapsulation layer 300 . Also, the lead-out terminals 400 in the second substrate 200 are also exposed from the plastic encapsulation layer 300 . In this embodiment, the plastic sealing layer 300 also covers the surface of the second substrate 200 away from the first substrate 100 , as long as the lead terminals 400 are exposed.

To sum up, in the intelligent power module provided in this embodiment, by arranging the driver chip and the power chip on the first substrate and the second substrate, respectively, the first substrate and the second substrate can face each other. It is arranged in the same way that the driver chip and the power chip can be arranged vertically in the thickness direction, which greatly reduces the mounting area of the module and realizes the miniaturization of the module (for example, in a specific example, compared with the one shown in FIG. 2 ) In terms of modules, the module area in this embodiment can be reduced by about 30%.). In addition, for the first substrate and the second substrate arranged facing each other, it is also beneficial to expose the back surface of the first substrate on which the power chip is arranged, so as to improve the heat dissipation effect.

Further, the second substrate provided with the driver chip may specifically be a printed circuit board. On the one hand, a more complex circuit arrangement can be realized in a smaller volume, and the driver chip can be directly flipped on the printed circuit board. There is no need to perform external wiring on the driver chip; on the other hand, it is also beneficial to extend the lead-out terminal from the second substrate, so that the length of the lead-out terminal is shorter, which is beneficial to reduce signal interference.

In addition, in this embodiment, the first substrate and the second substrate are arranged opposite to each other, and the surfaces of the first substrate and the second substrate that face away from each other are used as the main heat dissipation surface and the electrical lead-out surface (that is, the surface on which the lead-out terminals are arranged). ), so that the heat dissipation path and the electrical path flow in opposite directions, reducing interference. At the same time, the current flow paths on the first substrate and the current flow paths on the second substrate may be opposite or substantially opposite or in opposite trends, so that the circuits on the first substrate flow through the current paths on the second substrate mutual inductance to reduce stray inductance and help to cancel self-inductance.

It should be noted that, although the present invention has been disclosed above with preferred embodiments, the above embodiments are not intended to limit the present invention. For any person skilled in the art, without departing from the scope of the technical solution of the present invention, many possible changes and modifications can be made to the technical solution of the present invention by using the technical content disclosed above, or modified into equivalents of equivalent changes. Example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention still fall within the protection scope of the technical solutions of the present invention.

Also, it should be appreciated that the terminology described herein is used to describe particular embodiments only, and not to limit the scope of the present invention. It must be noted that, as used herein and in the appended claims, the singular forms "a" and "an" include plural references unless the context clearly dictates otherwise. For example, reference to "a step" or "a means" means a reference to one or more steps or means, and may include sub-steps as well as sub-means. All conjunctions used should be understood in their broadest sense. Also, the word "or" should be understood to have the definition of a logical "or" rather than a logical "exclusive or" unless the context clearly dictates otherwise. Furthermore, implementation of methods and/or apparatuses in embodiments of the present invention may include performing selected tasks manually, automatically, or a combination.

Claims (10)

1. A package structure of an intelligent power module, comprising: a first substrate provided with a power chip, a second substrate provided with a driver chip, and the first substrate and the second substrate are packaged and fixed the plastic layer; Wherein, the side of the first substrate with the power chip faces the side of the second substrate with the driver chip, and the side of the first substrate away from the power chip is exposed from the plastic sealing layer. 2 . The package structure of an intelligent power module according to claim 1 , wherein the first substrate is a metal-clad ceramic substrate, and the metal layer on the surface of the metal-clad ceramic substrate facing away from the power chip extends from the plastic package. 3 . layer exposed. 3 . The package structure of an intelligent power module according to claim 1 , wherein a plurality of lead-out terminals penetrating through the second substrate are formed in the second substrate, and the lead-out terminals extend from the second substrate. 4 . The side facing away from the driving chip protrudes. 4 . The package structure of an intelligent power module according to claim 3 , wherein the plastic encapsulation layer covers a side of the second substrate away from the driving chip, and the lead-out terminals are exposed from the plastic encapsulation layer. 5 . out. 5 . The package structure of an intelligent power module according to claim 1 , wherein the second substrate is a printed circuit board, and the driving chip is flip-chip mounted on the printed circuit board, and is connected to the printed circuit board. 6 . The electrical connections of the lines in the board. 6 . The package structure of an intelligent power module according to claim 1 , wherein a connecting column is further provided between the first substrate and the second substrate, and the first substrate and the second substrate They are electrically connected through the connecting posts. 7. A packaging method for an intelligent power module, comprising: A power chip is provided on the first substrate, and a driving chip is provided on the second substrate; and, The side of the first substrate with the power chip faces the side of the second substrate with the drive chip for injection molding to form a plastic encapsulation layer, and the side of the first substrate away from the power chip is exposed from the plastic encapsulation layer. 8 . The packaging method for an intelligent power module according to claim 7 , wherein the second substrate is a printed circuit board, the driving chip is flip-chipped on the printed circuit board, and is connected to the printed circuit board. 9 . The electrical connections of the lines in the board. 9 . The packaging method of an intelligent power module according to claim 7 , wherein a plurality of lead-out terminals penetrating through the second substrate are formed in the second substrate, and after injection molding and packaging, the lead-out terminals are formed from the The plastic encapsulation layer is exposed. 10 . The packaging method of an intelligent power module according to claim 7 , wherein, before performing injection molding and packaging, a connecting column is arranged on the first substrate or the second substrate, and the first substrate and the second substrate are connected with the connecting column. The second substrate is assembled so that the two ends of the connecting column are fixedly connected to the first substrate and the second substrate.

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