A high power density module with three-dimensional chip stacking

Abstract

The present invention relates to the field of power module technology, and in particular to a high-power density module with three-dimensional chip stacking. The high-power density module with three-dimensional chip stacking includes a first component, a second component, and a plastic package. The second copper layer is located above the first copper layer and is parallel to each other and spaced apart, and a connecting copper busbar connects the second copper layer and the first copper layer. The modular design of the second component allows its quantity to be flexibly increased or decreased according to power requirements without relying on complex wiring or an intermediate layer. The chip terminals of the first component and the second component are first independently placed in the upright position for reflow soldering, and then the second component is inverted and ultrasonically welded to the first copper layer through the connecting copper busbar, thereby overcoming the technical obstacles of multiple reflow soldering leading to increased thermal resistance of the metal layer and easy falling off of the inverted soldering solder. The end faces of the first copper layer and the second copper layer facing away from each other are flush with the plastic package and exposed, and a heat sink can be directly connected to achieve good heat dissipation of the chip.

Description

Technical Field

[0001] The present invention relates to the technical field of power modules, and in particular to a high-power density module with three-dimensional chip stacking. Background Art

[0002] In high-power application scenarios of traditional power modules, existing power modules generally adopt the practice of planar parallel DBC or AMB substrates when increasing the current capacity, which leads to an increase in the horizontal area and an increase in parasitic inductance. Therefore, in the prior art, in order to achieve multi-layer chip stacking and electrical connection, it is often necessary to use reflow soldering for soldering and assembly after the components are inverted. However, if each component is reflowed step by step, for example, the chip terminals are soldered first and then the connecting copper busbars are soldered, there is a problem that the metal layer of the solder of the first reflow soldering thickens after multiple reflows, resulting in a significant increase in the thermal resistance of the module, which seriously affects the heat dissipation efficiency. If an attempt is made to invert all components for reflow soldering at one time, there is a technical problem that the solder is easy to fall off due to gravity in a molten state, resulting in unreliable connection, low yield, and poor process feasibility.

[0003] In addition, improving the current carrying capacity and power density of existing power modules usually requires increasing the size of single modules or connecting multiple independent modules in parallel externally. This not only significantly increases the system volume and wiring complexity, but also leads to increased parasitic parameters and difficulties in thermal management due to the additional connection interfaces. Especially for stacked structures, existing technologies generally adopt fixed-layer designs or overall substrate replacement solutions, which makes it difficult to easily adjust the number of internal power units in parallel without redesigning the substrate layout and packaging structure. For example, if traditional flip-chip modules need to expand power, they often need to customize overall substrates with different layers. The overall flexibility is insufficient, and there is a lack of effective means to achieve a step-by-step expansion of power levels through the free combination of standardized components in a single package. Summary of the Invention

[0004] In view of this, the present invention provides a high power density module with three-dimensional chip stacking to solve the above technical problems.

[0005] A high-power density module with three-dimensional chip stacking, comprising a first component, at least one second component arranged on the first component, and a plastic package arranged on the first component and the second component, wherein the first component comprises a first copper layer, at least one first chip arranged on the first copper layer, an input terminal arranged on the first copper layer, and at least one first output terminal arranged on the first chip, the second component comprises a second copper layer, a plurality of connecting copper bars arranged on one side of the second copper layer, two second chips arranged on the second copper layer, and a second output terminal arranged on the second chip, the second copper layer is located above the first copper layer and is parallel to each other and arranged at intervals, one end of the connecting copper bar is connected to the second copper layer, and the other end is provided with a bending portion and connected to the first copper layer, so that the second copper layer is electrically connected to the first copper layer and the plurality of chips in the second copper layer and the first copper layer are connected in parallel, the chips and terminals in the first component and the second component are first placed upright and soldered using reflow soldering, and after completion, the second component is inverted and the connecting copper bar and the first copper layer are connected by ultrasonic welding.

[0006] Furthermore, one end of the input terminal is connected to the first copper layer, and the other end extends out of the plastic package and is connected to an external power supply. Each of the first output terminals is connected to two first chips. One end of the first output terminal is connected to the first chip, and the other end extends out of the plastic package and is connected to an external load device.

[0007] Furthermore, the first component also includes at least one first signal terminal arranged on the first chip, and the second component also includes a second signal terminal arranged on the second chip, one end of the first signal terminal is connected to the first chip, and the other end extends out of the plastic package and is connected to the external control circuit.

[0008] Furthermore, the second chip, the second output terminal, and the second signal terminal are arranged on an end surface of the second copper layer facing the first component.

[0009] Furthermore, the structures and functions of the second chip, the second output terminal, and the second signal terminal are the same as those of the first chip, the first output terminal, and the first signal terminal.

[0010] Furthermore, the plastic package is formed by coating the first component and the second component with a sealing material and then curing the sealing material.

[0011] Furthermore, end surfaces of the first copper layer and the second copper layer facing away from each other are flush with the plastic package body and exposed from the plastic package body.

[0012] Compared with the prior art, the present invention provides a high-power density module with a three-dimensional chip stack. The chip terminals of the first and second components are first reflowed independently in an upright position, and then the second component is inverted and ultrasonically welded to the first copper layer through the bent portion of the connecting copper busbar. This effectively overcomes the technical obstacles of multiple reflows leading to increased metal layer thickness and thermal resistance and easy detachment of inverted soldering solder, significantly reducing thermal resistance and improving heat dissipation efficiency. The inverted and parallel first and second copper layer structures significantly reduce the parasitic inductance of the module by using magnetic field cancellation. The modular design of the second component allows its number to be flexibly increased or decreased according to power requirements. The number of the second components can be increased or decreased in high-power or low-power application scenarios. At the same time, the connection method is simple and does not require reliance on complex wiring or intermediary layers. This allows a step-by-step increase in power density and a significant enhancement of current carrying capacity within the same package horizontal area. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic structural diagram of a high-power density module with three-dimensional chip stacking provided by the present invention.

[0014] Figure 2 for Figure 1 Schematic diagram of the structure of a high-power density module with three-dimensional chip stacking without the plastic package.

[0015] Figure 3 for Figure 1 Schematic diagram of the decomposed structure of a high-power density module with three-dimensional chip stacking.

[0016] Figure 4 for Figure 1 Schematic diagram of the decomposed structure of a high-power density module with three-dimensional chip stacking from another angle.

[0017] Figure 5 for Figure 1 A schematic structural diagram of a high-power density module with three-dimensional chip stacking, with the plastic package removed from another angle.

[0018] Reference numerals: first component 10 , second component 20 , plastic package 30 , first copper layer 11 , first chip 12 , input terminal 13 , first output terminal 14 , first signal terminal 15 , second copper layer 21 , connecting copper bus 22 , second chip 23 , second output terminal 24 , second signal terminal 25 , bending portion 26 . DETAILED DESCRIPTION

[0019] The following is a further detailed description of specific embodiments of the present invention. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the scope of protection of the present invention.

[0020] like Figures 1 to 5 , which is a schematic structural diagram of a high-power density module with three-dimensional chip stacking provided by the present invention. The high-power density module with three-dimensional chip stacking includes a first component 10, at least one second component 20 disposed on the first component 10, and a plastic package 30 disposed on the first component 10 and the second component 20. It is conceivable that the high-power density module with three-dimensional chip stacking also includes other functional modules, such as connection components and mounting components, etc., which are well known to those skilled in the art and will not be described in detail here.

[0021] The first component 10 includes a first copper layer 11, at least one first chip 12 arranged on the first copper layer 11, an input terminal 13 arranged on the first copper layer 11, at least one first output terminal 14 arranged on the first chip 12, and at least one first signal terminal 15 arranged on the first chip 12.

[0022] The first copper layer 11 is used to realize circuit connection, and the first chip 12 is used to realize the conversion, control and transmission of electric energy. Its own function should be technical and will not be repeated here. In this embodiment, four first chips 12 are provided, which can be set according to the actual power output size.

[0023] One end of the input terminal 13 is connected to the first copper layer 11, and the other end extends out of the plastic package 30 and is connected to the external power supply. The input terminal 13 is the interface for connecting the power module and the external power supply, and its main function is to introduce the electrical energy of the external power supply into the first copper layer 11.

[0024] Each of the first output terminals 14 is connected to two of the first chips 12 . The number of the first output terminals 14 is set according to the number of the first chips 12 . In this embodiment, two first output terminals 14 are provided.

[0025] One end of the first output terminal 14 is connected to the first chip 12, and the other end extends out of the plastic package 30 and is connected to an external load device. The first output terminal 14 is an interface for the power module to output processed electrical energy to an external load. Its main function is to transmit the converted electrical energy to an external device. The current is input into the first copper layer 11 through the input terminal 13, and at the same time flows into the multiple first chips 12. After conversion by the first chip 12, it is output from the multiple first output terminals 14.

[0026] One end of the first signal terminal 15 is connected to the first chip 12 , and the other end extends out of the plastic package 30 and is connected to an external control circuit. The first signal terminal 15 is used to control the chip.

[0027] The second component 20 includes a second copper layer 21, a plurality of connecting copper bars 22 arranged on one side of the second copper layer 21, two second chips 23 arranged on the second copper layer 21, a second output terminal 24 arranged on the second chip 23, and a second signal terminal 25 arranged on the second chip 23.

[0028] The second copper layer 21 is located above the first copper layer 11 and is parallel to each other and spaced apart, so that the two copper layers are parallel to each other and spaced apart, and the magnetic fields between the two cancel each other out, thereby reducing the parasitic inductance of the module. One end of the connecting copper bus 22 is integrally connected to the second copper layer 21, and the other end is provided with a bent portion 26 and connected to the first copper layer 11, so that the second copper layer 21 is connected to the first copper layer 11 in circuit communication, thereby connecting the second copper layer 21 and the plurality of chips in the first copper layer 11 in parallel, which can significantly increase the total current handling capacity of the power module. For example, if the chip of the first component 10 can carry a current of 100A, then two second components 20 in parallel can carry a current of 200A. This design can achieve higher power output in the same package volume, thereby improving power density, and can be better applied to high power or low power scenarios. In high power application scenarios, the number of the second components 20 can be increased to further improve the current carrying capacity and power density of the power module. For example, connecting two or more second components 20 in parallel can significantly increase the total current handling capacity of the module. In low-power applications, the number of second components 20 can be reduced to simplify the design and reduce costs, for example, only one second component 20 can be provided. Furthermore, the inverted stacking of the first and second components 10, 20 makes the module structure more compact. Without expanding the horizontal direction, vertical space is utilized to achieve three-dimensional chip stacking and allow heat to be conducted on both sides through multiple paths. The bent portion 26 is interconnected with the connecting copper bus 22 and connected to the first copper layer 11. The bent portion 26 is used to provide a larger area, thereby increasing the soldering area and connection area, and providing a stable planar support for the second copper layer 21.

[0029] The second chip 23, the second output terminal 24, and the second signal terminal 25 are arranged on the end surface of the second copper layer 21 facing the first component 10. The structure and function of the second chip 23, the second output terminal 24, and the second signal terminal 25 are the same as the structure and function of the first chip 12, the first output terminal 14, and the first signal terminal 15. They are used to convert the current of the second copper layer 21 and output it through the second output terminal 24, and will not be repeated here.

[0030] The chips and terminals in the first component 10 and the second component 20 are first placed upright and soldered using reflow soldering. After completion, the second component 20 is inverted and connected to the connecting copper bus 22 and the first copper layer 11 by ultrasonic welding. In traditional AMB inverted connection, if the terminals and chips are first reflow soldered, and then the connecting copper bus is reflow soldered, the requirements for solder are very high, and multiple reflow soldering will cause the metal layer formed by the solder of the first reflow soldering to thicken, affecting thermal resistance. If directly inverted and soldered together, the inverted solder may fall after melting, causing connection failure, which is insufficient in process feasibility. Therefore, three components are used to complete a reflow soldering each, and then the second component 20 is inverted and connected by ultrasonic welding, which avoids the problem of multiple reflow soldering, ensures that the thickness of the metal layer will not increase due to multiple reflows, optimizes thermal resistance, and ultrasonic welding will not cause the metal layer to thicken, so it is very friendly to thermal resistance, can effectively reduce thermal resistance, and improve heat dissipation efficiency. Because each component can undergo a separate reflow soldering cycle and then be ultrasonically connected, the inverted second component 20 is modularized, allowing the number of inverted second components 20 to be flexibly adjusted while maintaining the first component 10. This design offers a high degree of flexibility and scalability, allowing for rapid adjustments based on actual needs without requiring the entire substrate to be re-manufactured and redesigned.

[0031] The plastic encapsulation body 30 is formed by encapsulating the first and second components 10, 20 with a sealing material such as epoxy resin and then curing it, thereby achieving a seal to enhance insulation and inhibit environmental corrosion. When only one second component 20 is provided, the plastic encapsulation body 30 can fill the remaining space, automatically adapting to various numbers of second components 20 and improving adaptability. The end surfaces of the first and second copper layers 11, 21 facing away from each other are flush with the plastic encapsulation body 30 and exposed from the plastic encapsulation body 30, allowing the exposed end surfaces to be directly connected to an external heat sink to achieve good heat dissipation from the first and second components 10, 20, and achieve high power density.

[0032] Compared to the prior art, the present invention provides a high-power density module with a three-dimensional chip stack. The chip terminals of the first and second components 10 and 20 are first reflowed independently and upright, and then the second component 20 is ultrasonically welded to the first copper layer 11 through the bend 26 of the connecting copper busbar 22. This effectively overcomes the technical obstacles of increased metal layer thickness and thermal resistance caused by multiple reflows and the easy detachment of solder during inverted soldering, significantly reducing thermal resistance and improving heat dissipation efficiency. The inverted and parallel arrangement of the first and second copper layers 11 and 21 significantly reduces the module's parasitic inductance by utilizing magnetic field cancellation. The modular design of the second component 20 allows for flexible adjustment based on power requirements. The number of second components 20 can be increased or decreased in high-power or low-power applications. The connection method is simple, eliminating the need for complex wiring or interposers. This allows for a step-by-step increase in power density and a significant enhancement in current carrying capacity within the same package footprint.

[0033] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements or improvements within the spirit of the present invention are included in the scope of the claims of the present invention.

Claims

1. A high power density module with three-dimensional chip stacking, characterized by: The high-power density module with three-dimensional chip stacking includes a first component, at least one second component arranged on the first component, and a plastic package body arranged on the first component and the second component. The first component includes a first copper layer, at least one first chip arranged on the first copper layer, an input terminal arranged on the first copper layer, and at least one first output terminal arranged on the first chip. The second component includes a second copper layer, multiple connecting copper bars arranged on one side of the second copper layer, two second chips arranged on the second copper layer, and a second output terminal arranged on the second chip. The second copper layer is located above the first copper layer and is parallel to each other and arranged at intervals. One end of the connecting copper bar is connected to the second copper layer, and the other end is provided with a bending portion and connected to the first copper layer, so that the second copper layer is circuit-connected with the first copper layer and the multiple chips in the second copper layer and the first copper layer are connected in parallel. The chips and terminals in the first and second components are first placed upright and soldered using reflow soldering. After completion, the second component is inverted and the connecting copper bar and the first copper layer are connected by ultrasonic welding.

2. The high power density module with three-dimensional chip stacking according to claim 1, characterized in that: One end of the input terminal is connected to the first copper layer, and the other end extends out of the plastic package and is connected to an external power supply. Each of the first output terminals is connected to two first chips. One end of the first output terminal is connected to the first chip, and the other end extends out of the plastic package and is connected to an external load device.

3. The high power density module with three-dimensional chip stacking according to claim 1, wherein: The first component further includes at least one first signal terminal arranged on the first chip, and the second component further includes a second signal terminal arranged on the second chip. One end of the first signal terminal is connected to the first chip, and the other end extends out of the plastic package and is connected to the external control circuit.

4. The high power density module with three-dimensional chip stacking according to claim 3, characterized in that: The second chip, the second output terminal, and the second signal terminal are arranged on an end surface of the second copper layer facing the first component.

5. The high power density module with three-dimensional chip stacking according to claim 3, characterized in that: The structures and functions of the second chip, the second output terminal, and the second signal terminal are the same as those of the first chip, the first output terminal, and the first signal terminal.

6. The high power density module with three-dimensional chip stacking according to claim 1, characterized in that: The plastic package is formed by coating the first component and the second component with a sealing material and then curing the sealing material.

7. The high power density module with three-dimensional chip stacking according to claim 1, characterized in that: End surfaces of the first copper layer and the second copper layer facing away from each other are flush with the plastic package body and exposed from the plastic package body.

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