Double-Side Cooling Semiconductor Device Bus Bar Inductance Reduction
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Solution Overview
Problem
Conventional semiconductor devices with double-side cooling structures face an increase in inductance due to external connection terminals, which can lead to surge voltages during switching, especially when the terminals are thick and protrusions occur in the sealing resin body during molding.
Innovation Solution
The semiconductor device features a bus bar electrically connected to the heatsinks without external connection terminals, with coolers thermally connected to heat dissipation regions on the exposed surfaces of the heatsinks, and insulating plates separating the heat dissipation and electrical connection regions to prevent contact between the coolers and bus bars, thereby reducing inductance and suppressing surge voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external connection terminals are used to electrically connect heatsinks to bus bars, then electrical connection is achieved, but inductance increases causing surge voltages during switching
Solution Approach 1:
The patent removes external connection terminals from the system by establishing direct electrical connection between heatsinks and bus bars. The heatsink exposed surfaces serve dual purposes as both thermal dissipation areas and electrical connection interfaces, eliminating the need for separate terminal components that would increase inductance.
Solution Approach 2:
The heatsink exposed surfaces perform multiple functions simultaneously: they serve as thermal dissipation regions for heat transfer to coolers and as electrical connection regions for direct connection to bus bars. This multi-functionality eliminates the need for separate terminal components.
2Reliability
If thick external connection terminals are used for electrical connection, then electrical conductivity is improved, but resin protrusion occurs during molding of the sealing resin body
Solution Approach 1:
The patent eliminates external connection terminals entirely, removing the source of the molding problem. By using the heatsink exposed surface directly for electrical connection, there is no separate terminal component that could cause resin protrusion during transfer molding.
Solution Approach 2:
The patent merges the electrical connection function with the thermal dissipation structure. The heatsink exposed surface that was previously used only for thermal purposes now also serves as the electrical connection interface, combining two functions into one component.
3Temperature
If coolers are mounted on heatsink exposed surfaces for heat dissipation, then thermal cooling is achieved, but contact with bus bars may occur causing electrical short circuits
Solution Approach 1:
The patent divides the heatsink exposed surface into distinct functional regions: a thermal dissipation region for cooler contact and an electrical connection region for bus bar attachment. This spatial segmentation prevents cooler contact with bus bars while maintaining both thermal and electrical functions.
Solution Approach 2:
Different regions of the heatsink exposed surface have different properties and functions. The thermal dissipation region is optimized for heat transfer with the cooler, while the electrical connection region is positioned and configured for secure electrical connection to the bus bar, with insulating separation between the two regions.
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 configuration effectively reduces inductance and suppresses surge voltages by eliminating external connection terminals and optimizing the thermal and electrical connections, enhancing the semiconductor device's performance and reliability.
Implementation Method 1
a first heatsink arranged on a side of the first main surface of the semiconductor chip and electrically connected to the first main electrode
Implementation Method 2
having a bus bar electrically connected as an electrical relay member
Data Source
AI summary
A semiconductor device of a double-side cooling structure having a bus bar electrically connected, and coolers independently arranged on both sides of the semiconductor device for cooling is provided. The semiconductor device includes: a semiconductor chip including an element, and has a first main surface and a second main surface; a sealing resin body having a first surface and a second surface and also having a side surface; a first heatsink arranged facing the first main surface and electrically connected to the first main electrode; and a second heatsink arranged facing the second main surface and electrically connected to the second main electrode. The first heatsink is exposed only to the first surface. The second heatsink is exposed only to the second surface. An exposed surface of a heatsink to be electrically connected to the bus bar has a heat dissipation region, and an electrical connection region.