Power Module Adapter Wiring for Thermal Stress Reduction
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Solution Overview
Problem
Power modules face challenges in high-temperature operations due to heat generation from high voltage and large current handling, requiring high heat resistance in configurations and bonding portions, while existing connection methods using copper wires risk damaging the power semiconductor elements and complicating equipment with oxidation concerns, and existing electrode structures increase mounting area and reduce reliability.
Innovation Solution
A power module design featuring an adapter with a main-electrode wiring member connected to the power semiconductor element's front-surface electrode, including an element connection portion, a board connection portion, and a connector connection portion, allowing connection to external electrodes without routing through the circuit board's conductive layer, using silver-sintered bonding and copper wiring to enhance heat dissipation and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If copper wire is used for connection between front-surface electrode and external terminal, then heat resistance is improved, but the power semiconductor element is damaged due to large hardness
Solution Approach 1:
The patent introduces an aluminum wire as an intermediary connection element between the front-surface electrode and external terminal. Although copper has superior heat resistance, its high hardness causes damage to the semiconductor element. The aluminum wire serves as a mediator that provides adequate electrical and thermal connection without the mechanical damage caused by copper, thus resolving the contradiction between heat resistance and element integrity.
Solution Approach 2:
The patent changes the material parameter of the connection wire from copper to aluminum. This parameter change reduces the hardness and mechanical stress on the front-surface electrode, preventing cracking and damage. While aluminum has slightly lower thermal conductivity than copper, the overall heat resistance is maintained through the optimized connection structure and silver sintering bonding, thus resolving the contradiction between heat resistance and element integrity.
2Temperature
If copper wire bonding is performed, then heat resistance is improved, but equipment complexity increases due to oxidation management requirements
Solution Approach 1:
The patent uses aluminum wire instead of copper wire for the connection. Aluminum is more abundant and easier to handle, and while it has lower thermal conductivity than copper, the overall heat resistance requirement is met through the silver sintering bonding structure. This material substitution eliminates the need for complex oxidation management equipment and processes, thus resolving the contradiction between heat resistance and equipment complexity.
3Ease of manufacture
If connection is routed through conductive layer on circuit board, then manufacturing is simplified, but mounting area increases
Solution Approach 1:
The patent segments the connection path into two parts: the aluminum wire connection from the front-surface electrode to the external terminal, and the silver sintering bonding connection within the semiconductor element. This segmentation allows the external connection to be made directly without routing through the circuit board's conductive layer, reducing the mounting area while maintaining manufacturing simplicity through the use of standard wire bonding and bonding processes.
4Temperature
If silver sintering-bonding is used for back-surface connection, then heat resistance is improved, but manufacturing precision is required for low-temperature sintering
Solution Approach 1:
The patent uses silver sintering-bonding with nano powder for the back-surface connection. The nano powder formulation allows sintering at lower temperatures compared to conventional silver bonding, which improves heat resistance. The low-temperature sintering process reduces the risk of damaging the semiconductor element while achieving strong bonding, thus resolving the contradiction between heat resistance and bonding precision through material parameter optimization.
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
The design enables reliable high-temperature operation of power modules by reducing thermal stress on the semiconductor elements, improving heat dissipation, and simplifying the manufacturing process, while avoiding the need for complex oxidation management and minimizing the mounting area.
Implementation Method 1
silver sintering-bonding with the application of low-temperature sintering phenomenon of a nano powder
Data Source
AI summary
A power module of the invention includes a power semiconductor element mounted on a circuit board, and an adapter connected to a front-surface main electrode of the element, wherein the adapter includes a main-electrode wiring member which is connected to the front-surface main electrode of the element; and wherein the main-electrode wiring member includes: an element connection portion connected to the front-surface main electrode of the element; a board connection portion which is placed outside the element connection portion and connected to the circuit board; and a connector connection portion which is placed outside the element connection portion and connected to an external electrode through a connector.