Stacked DBM Power Module Packaging for Larger Die Integration
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Solution Overview
Problem
Existing power module designs have limited die attach pad sizes, restricting the inclusion of larger semiconductor dies, leading to increased costs and integration challenges for modern high-current products.
Innovation Solution
A vertical stack of direct bonded metal (DBM) substrates is used, with one substrate reserved for power die attach pads and another for integrated circuit die attach pads, increasing the total available area within a fixed package size, and wire bonds connect dies across the stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single DBM substrate is used, then the package structure is simple, but the die attach pad area is limited
Solution Approach 1:
The patent transitions from a two-dimensional single substrate layout to a three-dimensional stacked configuration. Multiple DBM substrates are vertically stacked to create additional die attach pad areas without increasing the package footprint, effectively utilizing the vertical dimension to resolve the area limitation.
Solution Approach 2:
The single substrate is segmented into multiple separate DBM substrates stacked vertically. Each substrate can be independently designed and optimized for specific die attach requirements, allowing flexible allocation of pad areas for power die versus IC die while maintaining overall package integration.
2Power
If larger semiconductor dies are used, then current capacity increases, but the package integration becomes more difficult
Solution Approach 1:
By stacking substrates vertically, the patent accommodates larger semiconductor dies on individual substrates without increasing the horizontal package footprint. The vertical stacking allows each die to have adequate space while maintaining compact overall integration.
Solution Approach 2:
Wire bonds serve as intermediaries connecting dies across different stacked substrates. This intermediary connection method enables integration of larger dies that would be difficult to connect directly, facilitating package integration while supporting higher current capacity devices.
3Area of stationary object
If multiple substrates are stacked, then the available die attach pad area increases, but the manufacturing process becomes more complex
Solution Approach 1:
The packaging process is segmented into modular steps for each substrate layer. Each DBM substrate can be prepared, bonded, and wired independently before being integrated into the final stacked package, making the manufacturing process more manageable despite the increased number of components.
Solution Approach 2:
Substrates are prepared and dies are attached to individual substrates before stacking. This preliminary action on separate substrates simplifies the overall manufacturing process by allowing parallel processing and reducing the complexity of handling multiple components simultaneously during assembly.
4Reliability
If wire bonds are used to connect dies across substrates, then electrical connectivity is achieved, but the package height increases
Solution Approach 1:
Wire bonds are used as flexible intermediaries to create electrical connections between dies on stacked substrates. The wire bonding process allows for reliable electrical connectivity while accommodating the vertical separation between substrates, with the wire length and routing optimized to minimize height increase.
Data Source
AI summary
A package includes a first direct bonded metal (DBM) substrate, a first semiconductor die disposed on a top surface of the first DBM substrate, a second DBM substrate disposed at a height above the first DBM substrate, and a second semiconductor die disposed on a top surface of the second DBM substrate. A wire bond is made between the first semiconductor die disposed on the top surface of the first DBM substrate and the second semiconductor die disposed on the top surface of the second DBM substrate.