Semiconductor Package Thermal Isolation for High Temperature Operation
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Solution Overview
Problem
Conventional semiconductor device packages struggle to operate at high temperatures without damaging printed circuit boards (PCBs) due to inadequate heat dissipation and increased current leakage in high-power devices like silicon carbide (SiC) devices.
Innovation Solution
A semiconductor package design featuring a thermally resistant encapsulant with low thermal conductivity bond wires and a thermal resistance layer between stacked power devices, which isolates the high-temperature device from the PCB, allowing heat radiation and controlling current leakage by sequencing the activation and deactivation of switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional packages conduct heat through die pad and leads to PCB, then heat dissipation is achieved, but PCB temperature exceeds safe operating range
Solution Approach 1:
The package structure segments the thermal path by introducing a thermally resistant encapsulant material that isolates the hot device region from the PCB, allowing the device to operate at high temperatures without transferring excessive heat to the PCB
Solution Approach 2:
A thermally resistant encapsulant material acts as an intermediary between the high-power device and the PCB, blocking thermal conduction while maintaining electrical connectivity through the leads
2Productivity
If SiC devices are used for high voltage switching, then switching performance is improved, but current leakage increases
Solution Approach 1:
A lower threshold voltage device is activated before the high-voltage SiC device to preemptively block leakage current paths, ensuring that when the main device is deactivated, the leakage path is already protected by the pre-activated protective device
3Temperature
If device is thermally isolated from PCB, then high temperature operation is enabled, but heat dissipation path is reduced
Solution Approach 1:
The package employs local quality by providing thermal isolation specifically at the device-PCB interface while maintaining thermal pathways through other components like the encapsulant and surrounding structures, allowing high temperature operation without complete thermal blockage
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 enables high-power semiconductor devices to operate at elevated temperatures without damaging the PCB, effectively preventing current leakage and optimizing switching performance while maintaining low-temperature device integrity.
Implementation Method 1
the package is configured with the die pad at the top of the package, facing away from the PCB... the die operates at a high temperature and radiates heat away from the PCB
Implementation Method 2
a high temperature power device is stacked on a second power device with a high thermal resistance layer therebetween
Data Source
AI summary
The invention provides a semiconductor device that is thermally isolated from the printed circuit board such that the device operates at a higher temperature and radiates heat away from the printed circuit board. In another embodiment, the semiconductor is stacked onto a second device and optionally thermally isolated from the second device.