Nested Metal Clip Layout for Compact GaN Half-Bridge IPMs
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Solution Overview
Problem
High power circuitry in integrated power modules (IPMs) face challenges in reducing module sizes due to the need for large capacitors and thick aluminum wedge bonding, which requires additional spacing, limiting further size reduction in compact system designs.
Innovation Solution
The use of nested metal clips with different heights for transistor source and drain connections, allowing for compact interconnections without the need for extensive lateral spacing, and providing improved current carrying capability and reduced inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thick aluminum wedge bonding is used for high current connections, then current carrying capability is improved, but additional spacing is required between terminal connection points and adjacent components, increasing device footprint
Solution Approach 1:
The patent implements nested metal clips where a first metal clip and a second metal clip are positioned such that they overlap in plan view. The first metal clip has first and second end portions coupled to transistor terminals, while the second metal clip has end portions coupled to substrate conductive traces. The middle portion of the second metal clip overlies a portion of the first metal clip, creating a nested configuration that reduces the lateral spacing required between connection points while maintaining high current carrying capability through the combined cross-sectional area of both clips.
2Reliability
If wedge bonding tools are used for thick aluminum bonding, then reliable high current connections are achieved, but the size of the bonding tools requires additional spacing, limiting module size reduction
Solution Approach 1:
The patent transitions from lateral spacing requirements to vertical stacking by implementing metal clips that extend in the vertical dimension. The nested configuration allows the clips to overlap when viewed from above, utilizing the vertical space above the substrate and transistor die to achieve three-dimensional current paths. This dimensional transition eliminates the need for lateral spacing dictated by wedge bonding tool size while maintaining connection reliability through proper mechanical and electrical contact between the nested clips and their respective connection points.
3Adaptability or versatility
If alternating field effect transistor source and drain terminals are used, then wedge wire bonding tooling spacing requirements are accommodated, but further size reduction is limited
Solution Approach 1:
The patent employs nested metal clips that overlap in plan view to connect alternating FET source and drain terminals to substrate conductive traces. This nested configuration reduces the lateral footprint required for wire bonding tooling operations while maintaining adaptability to standard bonding processes. The overlapping clips provide multiple current paths and reduce the spacing between connection points, enabling further module size reduction while preserving tooling compatibility for wire bonding operations.
Data Source
AI summary
An electronic device includes a substrate having first and second conductive traces, a semiconductor die having a transistor with a first terminal and a second terminal, and first and second metal clips. The first metal clip has a first end portion coupled to the first terminal of the transistor, and a second end portion coupled to the first conductive trace of the substrate. The second metal clip has a first end portion coupled to the second terminal of the transistor and a second end portion coupled to the second conductive trace of the substrate, and a middle portion of the second metal clip is spaced apart from and at least partially overlying a portion of the first metal clip.