Bridging DMB Structure for Wire Bonding in Power Modules
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Solution Overview
Problem
Existing power semiconductor device modules face challenges in efficiently managing high current paths, mechanical strength of bonding wires, and heat sinking, with crossing bonding wires prone to shorting and inadequate thermal transfer.
Innovation Solution
The introduction of a novel bridging Direct Metal Bonded (DMB) structure that serves as a bridge for wire or ribbon bonding, allowing for increased current carrying metal in the substrate DMB structure, enhancing mechanical strength, and promoting heat sinking by patterning the top and bottom metal layers into islands to prevent shorting and improve thermal contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonding wires are used to interconnect semiconductor devices, then electrical connections are established, but the wires are prone to shorting and lack mechanical strength
Solution Approach 1:
The patent introduces a bridging DMB structure as an intermediary element between external connection terminals and semiconductor device dice. This mediator provides robust mechanical support and electrical connectivity, eliminating the need for weak bonding wires to span long distances while preventing shorting between adjacent wires.
Solution Approach 2:
The patent segments the electrical connection path into multiple sections: external terminals connect to the bridging DMB structure, which then connects to individual semiconductor dice. This segmentation allows each segment to be optimized independently, with the bridging structure providing mechanical strength and the wire bonds providing flexible electrical connections over shorter distances.
2Temperature
If bonding wires are used for interconnection, then electrical paths are created, but heat sinking from bonding wires is inadequate
Solution Approach 1:
The bridging DMB structure serves as a thermal intermediary, conducting heat away from the bonding wires and semiconductor devices. The metal layers in the bridging structure provide low-thermal-resistance paths to the heat sink, effectively mediating heat transfer from the high-temperature regions to the cooling system.
Solution Approach 2:
The bridging DMB structure performs multiple functions simultaneously: it provides electrical connectivity, mechanical support, and thermal management. This multi-functionality eliminates the need for separate components for each function, improving overall system efficiency and reliability.
3Power
If more current carrying metal is provided in the substrate DMB structure, then high current paths are improved, but device complexity increases
Solution Approach 1:
The patent segments the metal layers into functionally distinct regions: the bridging DMB structure contains metal layers optimized for low-current signal paths, while the substrate DMB structure contains metal layers optimized for high-current power paths. This segmentation allows each region to be optimized for its specific function without increasing overall complexity.
Solution Approach 2:
The patent applies local quality by providing different metal layer configurations in different locations: the substrate DMB structure has thick, extensive metal layers for high current carrying capacity where needed, while the bridging structure has thinner metal layers sufficient for low current signal paths, optimizing material usage and reducing unnecessary 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
This solution enables more efficient current management, increased mechanical strength of bonding wires, and improved heat sinking, reducing the susceptibility of bonding wires to breakage and enhancing thermal transfer within the module.
Implementation Method 1
an insulative but heat-conductive center ceramic substrate layer. A planar bottom direct metal bonded metal layer is bonded to the bottom surface of the ceramic layer
Implementation Method 2
The various discrete semiconductor device dice and various portions of the DMB structure are interconnected by bonding wires
Data Source
AI summary
A power module includes a substrate DMB (Direct Metal Bonded). A novel bridging DMB is surface mounted to the substrate DMB along with power semiconductor device dice. The top metal layer of the bridging DMB has one or more islands to which bonding wires can connect. In one example, an electrical path extends from a module terminal, through a first bonding wire and to a first location on a strip-shaped island, through the island to a second location, and from the second location and through a second bonding wire. The strip-shaped island of the bridging DMB serves as a section of the overall electrical path. Another bonding wire of a separate electrical path passes transversely over the strip-shaped island without any wire crossing any other wire. Use of the bridging DMB promotes bonding wire mechanical strength as well as heat sinking from bonding wires down to the substrate DMB.