Parallel Chip Power Module Layout for Low Inductance Current Sharing
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Solution Overview
Problem
In power modules, the large number of aluminum wires used for connecting semiconductor chips increases parasitic inductance and leads to nonuniform current distribution and heat generation among chips connected in parallel, causing local overheating and performance issues.
Innovation Solution
A power module design that includes a first metal layer-coated substrate, multiple chips, and a first connection piece. The chips are connected in parallel using the first connection piece, which has a wider flow path than the current path, enhancing connectivity and reducing parasitic inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large quantity of aluminum wires are used to connect multiple chips in parallel, then the electrical connection between chips is improved, but parasitic inductance increases and current distribution becomes nonuniform
Solution Approach 1:
The patent extracts and eliminates the aluminum wires from the connection structure, replacing them with a copper foil-based connection piece. This removes the source of parasitic inductance while maintaining electrical connectivity through a different material and structural approach.
Solution Approach 2:
The patent changes the material parameter from aluminum wire to copper foil, and alters the geometric parameters by providing a wider flow path in the connection piece. These parameter changes reduce parasitic inductance and improve current distribution uniformity across parallel chips.
2Reliability
If multiple aluminum wires are used to connect chips in parallel, then electrical connectivity is achieved, but current equalization deteriorates due to nonuniform current distribution
Solution Approach 1:
The patent implements homogeneity by designing the connection piece with uniform copper foil thickness and consistent flow path width across all connection points. This ensures equal current distribution among parallel chips, eliminating the nonuniformity caused by varying wire lengths and contact points in traditional aluminum wire connections.
Solution Approach 2:
The wide flow path design in the connection piece creates equipotential regions that equalize current distribution across parallel chips, ensuring uniform heat generation and preventing localized overheating.
3Reliability
If aluminum wires are used for chip connections, then electrical connection is established, but local overheating occurs due to nonuniform heat generation
Solution Approach 1:
By changing from aluminum wire to copper foil with a wider flow path, the patent improves thermal distribution. The increased cross-sectional area and better thermal conductivity of copper foil result in more uniform heat generation across parallel chips, preventing localized overheating.
4Reliability
If multiple aluminum wires are used to connect parallel chips, then electrical connectivity is improved, but parasitic inductance increases affecting power module performance
Solution Approach 1:
The patent merges multiple individual wire connections into a single integrated copper foil connection piece. This consolidation reduces the number of discrete connection elements, minimizes parasitic inductance, and improves parameter consistency across all chip connections.
Data Source
AI summary
A power module includes a first metal layer-coated substrate, a plurality of chips, and a first connection piece. A first electrode of each chip is electrically connected to a first metal layer of the first metal layer-coated substrate. The first connection piece includes a first main body part and a plurality of first contact parts. A second electrode of each of the plurality of chips is in contact with at least one of the first contact parts. A part of the first main body part is between at least one pair of adjacent first contact parts. A current flowing out from the chip directly flows to the first main body part through the first contact part. The chips are connected in parallel by using the first connection piece.