Power Semiconductor Module Integrated Lead Frame Design
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Solution Overview
Problem
Conventional power semiconductor modules face challenges with size reduction, heat dissipation efficiency, internal resistance, and reliability due to bonding area constraints, low thermal conductivity, and complex wire bonding.
Innovation Solution
A power semiconductor module design featuring planar first metal plates with power semiconductor chips, overbridge-shaped second metal plates for solder bonding, and a resin package with a heat conductive member and pressing mechanism for improved heat dissipation and reduced internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external connection terminals and heat dissipation substrate are individually prepared and bonded by soldering, then reliable electrical connection is achieved, but bonding area increases and module size reduction is disturbed
Solution Approach 1:
The patent merges the external connection terminal and heat dissipation substrate into a single integrated structure. The lead frame serves dual functions as both electrical connection terminal and heat dissipation substrate, eliminating the need for separate components and their bonding processes. This integration directly reduces module size while maintaining reliable electrical connections through the unified structure.
Solution Approach 2:
The lead frame is designed to perform multiple functions simultaneously: it provides electrical connection terminals for power and signal transmission, acts as a heat dissipation substrate for thermal management, and serves as a structural support element. This multi-functionality eliminates redundant components and reduces overall module size while ensuring reliable electrical connections.
2Stability of the object's composition
If heat passes through the mold package with low thermal conductivity, then the resin package structure is maintained, but heat dissipation properties deteriorate requiring enlarged heat dissipation substrate area
Solution Approach 1:
The patent extracts the heat dissipation function from the low thermal conductivity mold package by providing a dedicated heat dissipation substrate with high thermal conductivity. The substrate is positioned to conduct heat away from the semiconductor devices directly, bypassing the thermal limitations of the resin package material. This allows the resin package to maintain its structural integrity while heat dissipation is handled by the specialized substrate.
Solution Approach 2:
The patent employs composite material construction where a high thermal conductivity substrate (such as metal) is integrated within the resin package structure. This composite approach combines the structural benefits of the resin package with the superior heat dissipation properties of the metal substrate, achieving both structural stability and effective heat management.
3Reliability
If multiple wire bonding are performed to secure current capacity, then electrical connection is achieved, but workability is constrained and internal resistance reduction is limited with increased complexity
Solution Approach 1:
The patent merges the functions of multiple wire bonds into a single integrated lead frame structure. The lead frame provides direct electrical connections between semiconductor devices and external terminals through its conductive traces and bonding pads, eliminating the need for multiple separate wire bonding operations. This integration maintains current capacity while significantly reducing manufacturing complexity.
Solution Approach 2:
The lead frame acts as an intermediary structure that provides direct electrical pathways between semiconductor devices and external terminals. Instead of using multiple wire bonds as intermediaries, the lead frame serves as a unified intermediate structure with built-in conductive traces that achieve the same electrical connection function with greater efficiency and lower complexity.
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 stable solder bonding, reduced internal resistance, enhanced thermal stress management, and improved reliability, while allowing for size reduction and cost-effective heat dissipation.
Implementation Method 1
a heat conductive member which is sandwiched between the power semiconductor module and the heat sink portion, the heat conductive member being for dissipating heat from the power semiconductor module
Implementation Method 2
a pressing mechanism which presses the power semiconductor module against the heat sink portion via the heat conductive member
Implementation Method 3
the leg sections being for appropriately performing solder bonding between electrodes of the power semiconductor chips and between the electrode of the power semiconductor chip and the first metal plate
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3~4
AI summary
A power semiconductor module includes: a plurality of first metal plates arranged in the same planar state; a power semiconductor chip mounted on the first metal plate; and an overbridge-shaped second metal plate which is composed of bridge frame sections and leg sections that support the bridge frame sections, the leg sections being for appropriately performing solder bonding between electrodes of the power semiconductor chips and between the electrode of the power semiconductor chip and the first metal plate, the power semiconductor module being configured by a resin package in which these members are sealed with electrically insulating resin. In the power semiconductor module, the solder bonding section of the leg section is formed in a planar shape by bending process and is provided at a position lower than the bridge frame section.