Multi-layer Circuit Board Power Module with Embedded Cavities
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Solution Overview
Problem
Existing power module manufacturing techniques face challenges in achieving low stray impedance and high power density due to complex layering processes and reliability issues with multiple interfaces, especially in compact applications like electric vehicles.
Innovation Solution
A power module design featuring a multi-layer circuit board with cavities that house power semiconductor devices, allowing for easy manufacturing with reduced bonding steps and improved reliability, utilizing prepreg material and metal substrates for low inductance and high thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If multiple current carrying layers are placed one after the other, then self-inductances and mutual inductances are reduced, but additional bonding processes are required and reliability decreases due to additional interfaces
Solution Approach 1:
The patent merges multiple current carrying layers into a single multi-layer circuit board structure where layers are formed simultaneously during PCB manufacturing rather than being bonded separately. This integration eliminates the need for additional bonding processes between layers while maintaining the low inductance benefit of multiple stacked layers, thus improving reliability without sacrificing electrical performance.
2Ease of manufacture
If power semiconductor devices are completely embedded into a printed circuit board structure, then manufacturing is simplified, but special top side metallization is required and via drilling depth is limited
Solution Approach 1:
The patent utilizes the vertical dimension by implementing multiple conductive layers stacked in the Z-direction of the circuit board. This allows current paths to extend through multiple layers via vias, effectively increasing the available via depth and insulation thickness without requiring overly complex single-layer metallization schemes. The multi-layer approach distributes the complexity across standard PCB manufacturing processes.
3Adaptability or versatility
If multiple layers are bonded together, then current routing flexibility is improved, but manufacturing complexity and process steps increase
Solution Approach 1:
The patent employs a multi-layer circuit board that serves multiple functions simultaneously: it provides mechanical support for power semiconductor devices, routes multiple current paths in different layers, provides electrical insulation between layers, and enables low-inductance current loops. By integrating these functions into a single standardized PCB structure, the design achieves current routing flexibility without proportionally increasing manufacturing complexity.
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
The solution enables a power module with low stray impedance and high power density, simplified manufacturing, and enhanced reliability by routing currents in multiple layers and using a metal substrate for cooling, while reducing the number of bonded contact areas and manufacturing steps.
Implementation Method 1
route currents in multiple vertically stacked layers
Implementation Method 2
using a metal substrate for cooling
Data Source
AI summary
A power module comprises at least one power semiconductor device with an electrical top contact area on a top side; and a multi-layer circuit board with multiple electrically conducting layers which are separated by multiple electrically isolating layers, the electrically isolating layers being laminated together with the electrically conducting layers; wherein the multi-layer circuit board has at least one cavity, which is opened to a top side of the multi-layer circuit board, which cavity reaches through at least two electrically conducting layers; wherein the power semiconductor device is attached with a bottom side to a bottom of the cavity; and wherein the power semiconductor device is electrically connected to a top side of the multi-layer circuit board with a conducting member bonded to the top contact area and bonded to the top side of the multi-layer circuit board.