Semiconductor Module Stray Capacitance Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor modules face challenges in reducing earth stray capacitance while maintaining effective cooling, as ceramic heat sinks have lower thermal conductivity than metal, leading to potential performance deterioration.
Innovation Solution
The semiconductor module connects an output electrode to a second electrode via an insulating member, which is then connected to a heat sink through another insulating member, creating a series circuit configuration that reduces stray capacitance and maintains efficient cooling by using a multi-layered ceramic substrate with insulating layers and metal patterns to minimize common mode current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ceramic material is used for heat sink to reduce earth stray capacitance, then noise reduction is improved, but thermal conductivity deteriorates
Solution Approach 1:
The patent employs a composite structure combining ceramic layers and metal layers in a multilayer substrate. The ceramic layers provide electrical insulation to reduce earth stray capacitance, while the metal layers provide high thermal conductivity for effective heat dissipation. This composite approach allows simultaneous achievement of noise reduction and thermal management.
Solution Approach 2:
The multilayer substrate serves multiple functions: it acts as an electrical insulator to reduce stray capacitance, a thermal conductor to dissipate heat, and a structural support for mounting semiconductor devices. By integrating these functions into a single composite structure, the patent resolves the contradiction between electrical insulation and thermal conduction.
2Object-generated harmful factors
If ceramic heat sink is used to reduce stray capacitance, then common mode current is reduced, but cooling performance deteriorates
Solution Approach 1:
The multilayer substrate combines ceramic and metal materials to achieve both electrical insulation for reducing common mode current and thermal conduction for maintaining cooling performance. The metal layers serve as thermal pathways while the ceramic layers provide electrical isolation.
Solution Approach 2:
The heat sink structure is segmented into multiple functional layers: ceramic layers for electrical insulation and metal layers for thermal conduction. This segmentation allows each layer to perform its specialized function optimally, with ceramic reducing common mode current and metal maintaining cooling performance.
3Object-generated harmful factors
If insulating members are introduced to reduce stray capacitance, then noise radiation is reduced, but thermal resistance increases
Solution Approach 1:
The patent uses a composite multilayer substrate where ceramic layers provide electrical insulation to reduce noise radiation, while integrated metal layers provide thermal conduction pathways to minimize thermal resistance. The metal layers act as heat spreaders that conduct heat away from semiconductor devices through the insulating ceramic structure.
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 common mode current and noise radiation, adhering to EMC standards while preventing cooling performance deterioration, and allows for a downsized heat sink without compromising thermal management.
Implementation Method 1
an output electrode is connected to a second electrode via an insulating member, and the second electrode is connected to a heat sink via another insulating member
Implementation Method 2
since the thermal conductivity of ceramic is lower than the thermal conductivity of metal, there is fear that the electric power conversion apparatus cannot be sufficiently cooled
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A semiconductor module has a pair of semiconductor devices 16, 18 that are connected in series with each other and have first terminals 12, 14 electrically connected to a first power system BT and a second terminal 13 electrically connected to a second power system M, a heat sink 7, a first electrode 10 that is electrically connected both to the first terminal 12, that is one of the first terminals, and to one of electrodes of the semiconductor device 16, that is one of the pair of semiconductor devices, an output electrode 11 that is electrically connected both to the second terminal 13 and to one of electrodes of the semiconductor device 18, that is the other one of the pair of semiconductor devices, and a second electrode 9 that is electrically connected to the first terminal 14, that is the other one of the first terminals. The second electrode 9 is connected to the heat sink 7 via a first insulating member 8a, and the output electrode 11 is connected to the second electrode 9 via a second insulating member 8b.