Stack Type Power Module Direct Bonding Heat Dissipation
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Solution Overview
Problem
Stack type power modules face challenges in achieving high-density, high-integration, and cost competitiveness due to the need for spacers and wire bonding, which limits thickness reduction and increases costs, while also requiring improved heat dissipation.
Innovation Solution
A stack type power module design where the power semiconductor and lead frame are directly connected through a substrate without wire bonding, using a flip chip process and insulating resin to ensure electrical insulation and heat dissipation, with a double-sided cooling structure formed by stacked metal and ceramic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is used to connect power semiconductor and lead frame, then electrical connection is achieved, but additional space is required due to loop height which increases module thickness and cost
Solution Approach 1:
The patent extracts and eliminates the wire bonding component from the connection system. By directly bonding the power semiconductor chip to the lead frame using solder or other bonding materials, the wire and its associated loop height are removed, thereby reducing module thickness while maintaining electrical connection functionality
Solution Approach 2:
The patent merges the power semiconductor chip directly with the lead frame through direct bonding, combining two previously separate connection elements (wire and chip-lead frame interface) into a single integrated bonding structure, eliminating the need for intermediate wire bonding and reducing overall thickness
2Reliability
If wire bonding and spacer are used for connection and space management, then electrical connection is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and removes the wire bonding process and spacer components from the assembly. The direct bonding approach eliminates multiple connection steps (wire bonding, spacer installation) reducing device complexity and manufacturing complexity while achieving reliable electrical connection
Solution Approach 2:
The direct bonding interface serves multiple functions simultaneously: it provides electrical connection, mechanical support, and thermal conduction pathways, eliminating the need for separate wire bonding and spacer components that previously performed these functions individually
3Ease of manufacture
If traditional stack type power module structure is used with wire bonding, then manufacturing is simpler, but heat dissipation performance is insufficient
Solution Approach 1:
The patent merges the electrical connection function with the thermal conduction function into a single direct bonding interface. The solder or bonding material creates a low-thermal-resistance pathway from the power semiconductor chip directly to the lead frame and heat sink, significantly improving heat dissipation while maintaining manufacturing simplicity
Solution Approach 2:
The patent employs composite bonding materials (such as solder alloys or advanced bonding compounds) that provide both excellent electrical conductivity and high thermal conductivity, enabling simultaneous achievement of reliable electrical connection and effective heat dissipation through the direct bonding interface
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances heat radiation performance, reduces the overall size, and lowers manufacturing costs by eliminating the need for spacers and wire bonding, achieving high-density and cost competitiveness.
Implementation Method 1
Each of the upper substrate layer and the lower substrate layer can be formed with the stacked structure of an upper metal layer, a ceramic layer, and a lower metal layer as the path discharging the heat generated in the power semiconductor to the outside
Implementation Method 2
An insulating resin can be filled through an underfill process. The insulating resin can be filled into the space between a plurality of terminal pads of the gate and the space between terminal pads between the gate and the emitter
Data Source
AI summary
A stack type power module includes: a power semiconductor having a gate and an emitter, each of which has a pad shape, adjacent to each other on one surface of the power semiconductor, and a collector having a pad shape on another surface of the power semiconductor; an upper substrate layer stacked on an upper portion of the power semiconductor, and electrically connected to a metal layer that has a lower surface with which the collector is in contact; and a lower substrate layer stacked on a lower portion of the power semiconductor, and electrically connected to the metal layer that has an upper surface with which each of the gate and the emitter is in contact.