Molded Power Semiconductor Package With Asymmetric Source Cooling
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Solution Overview
Problem
Current semiconductor devices face limitations in current rating due to ohmic heating of pins, particularly at the source leads, which exceed the allowed temperature of the board material, and lack effective cooling mechanisms for the source connection.
Innovation Solution
An asymmetric lead count is introduced with larger wire sizes for source connectors compared to drain connectors, allowing additional source leads to be connected to isolated heatsinks, enhancing thermal management and ampacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the current rating is increased beyond typical limits, then the ampacity of the semiconductor device is improved, but the temperature of the pins exceeds the allowed temperature due to ohmic heating
Solution Approach 1:
The invention segments the thermal management function by introducing separate thermal connectors that are electrically isolated from the electrical current path. These thermal connectors divide the thermal dissipation function from the electrical conduction function, allowing heat to be conducted away through dedicated thermal paths without carrying electrical current, thereby reducing ohmic heating in the electrical connectors.
Solution Approach 2:
The invention introduces thermal connectors as intermediary elements between the semiconductor die and the external environment. These thermal connectors serve as mediators that transfer thermal energy from the hot spot (semiconductor die) to the heatsink without being part of the electrical current path, thus eliminating the dual burden of carrying both electrical current and thermal load.
2Temperature
If the wire size of source connectors is increased to improve thermal management, then the thermal conductivity at the source side is improved, but the device complexity increases due to asymmetric lead configuration
Solution Approach 1:
The invention deliberately introduces asymmetry in the connector configuration, where thermal connectors are electrically isolated from the electrical current path. This asymmetric design allows the thermal connectors to have optimized wire sizes for thermal conduction without being constrained by electrical current carrying requirements, enabling independent optimization of thermal performance.
Solution Approach 2:
The thermal connectors serve multiple functions: they provide thermal conduction from the semiconductor die to the heatsink, while being electrically isolated to avoid carrying current. This multi-functionality allows the same connector structure to handle thermal management without interfering with electrical signal integrity.
3Temperature
If additional thermal connectors are introduced to improve cooling, then the thermal dissipation capability is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention merges the thermal connector structure with the existing electrical connector framework, where thermal connectors are integrated into the same package housing and mounting structure. By combining the thermal management function with the existing electrical connection architecture, the manufacturing process can leverage existing tooling and assembly procedures while adding thermal functionality.
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 thermal dissipation and reduces temperature differences between source and drain leads, enabling higher ampacity and effective cooling through additional thermal connectors.
Implementation Method 1
a second set of external connectors being spaced apart from the die carrier and electrically connected to the second load electrode... allowing additional source leads to be connected to isolated heatsinks, enhancing thermal management
Implementation Method 2
When exceeding the ampacity limit, ohmic heating of pins will cause a new overtemperature condition, that is, a temperature of the pins exceeds an allowed temperature
Data Source
AI summary
A semiconductor device includes a die carrier, a semiconductor die, a first set of external connectors, and a second set of external connectors. The semiconductor die includes at least a first load electrode and a second load electrode, and is mounted onto the die carrier with the first load electrode being electrically connected to the die carrier. The first set of external connectors is electrically and thermally connected to the die carrier. The second set of external connectors is spaced apart from the die carrier and electrically connected to the second load electrode. An overall wire size of the second set of external connectors is greater than an overall wire size of the first set of external connectors.