Power Module Lead Frame Structure for Heat Dissipation and Thermal Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power modules face inefficiencies in heat transfer from semiconductor chips to heat sinks, which hinders effective heat dissipation, and are prone to thermal stress due to differences in thermal expansion coefficients, affecting durability and operating temperature.
Innovation Solution
A power module design that includes lead frames with increased thickness and second metal layers with higher thermal conductivity, along with additional substrates to distribute thermal stress, enhances heat transfer and dissipation while maintaining durability by increasing the thickness of the metal layer between semiconductor chips and the insulating circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If lead frame thickness is increased to improve heat transfer from semiconductor chips to substrate, then heat dissipation efficiency is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies parameter changes by increasing the thickness of the lead frame from conventional dimensions to 0.5mm or more, fundamentally altering the thermal conduction capability of the lead frame. This parameter modification enables the lead frame to serve as an effective heat dissipation pathway, transforming it from a simple electrical connector to a dual-function component that simultaneously provides electrical connection and thermal management.
Solution Approach 2:
The patent implements multi-functionality by designing the lead frame to perform both electrical connection and heat dissipation functions. The thickened lead frame structure allows it to act as both a current carrier and a heat sink, eliminating the need for separate thermal management components in certain configurations and simplifying the overall device architecture despite the increased thickness.
2Loss of energy
If second metal layers with higher thermal conductivity are added to enhance heat transfer, then heat dissipation performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs composite materials by introducing second metal layers with superior thermal conductivity (such as copper or copper alloys) onto the lead frame or substrate surface. This creates a hybrid structure that combines the mechanical strength and electrical properties of the base lead frame with the exceptional heat conduction capabilities of the copper-based second metal layer, achieving optimized thermal management performance.
Solution Approach 2:
The patent applies local quality by selectively positioning second metal layers in specific high-heat-flux areas, such as directly beneath or adjacent to semiconductor chip mounting locations. This localized application of high-conductivity material concentrates thermal management resources where they are most needed, improving heat transfer efficiency without requiring uniform enhancement across the entire device structure.
3Reliability
If additional substrates are introduced to distribute thermal stress, then durability is improved, but device complexity increases
Solution Approach 1:
The patent addresses thermal expansion issues by introducing additional substrate layers with carefully selected thermal expansion coefficients that match or complement the semiconductor chips and lead frame. These substrate layers act as stress-absorbing intermediaries that accommodate differential thermal expansion during temperature cycling, preventing solder joint fatigue and delamination, thereby enhancing long-term reliability and durability of the power module.
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 improves heat diffusion and dissipation performance, lowering the operating temperature of the power module and ensuring durability by effectively managing thermal stress through enhanced thermal conductivity and stress distribution.
Implementation Method 1
transferring heat generated from a semiconductor chip to a substrate so that the generated heat is efficiently dispersed and released on the substrate by a lead frame
Implementation Method 2
a thermal expansion coefficient of each of the second metal layers may be greater than a thermal expansion coefficient of each of the semiconductor chips and smaller than a thermal expansion coefficient of each of the lead frames
Data Source
AI summary
A power module and a manufacturing method include semiconductor chips, an insulating circuit board including an insulating layer and a first metal layer disposed on a first surface of the insulating layer, and lead frames disposed between the semiconductor chips and the insulating circuit board.