Die Stacking Power Converter Package
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Solution Overview
Problem
Conventional integrated circuit packaging for high power switched mode power converters results in larger package sizes and introduces high interconnection resistance and parasitic inductance due to the need for wire bonding between separate semiconductor dies.
Innovation Solution
A semiconductor device with a first die having an electrically quiet surface and a second die for control, stacked on the first die, supported by a lead frame structure that electrically couples both dies to external circuitry, eliminating the need for wire bonding and reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate semiconductor dies are laid on a lead frame structure in the same plane, then the power converter can be assembled using conventional methods, but the package size becomes larger
Solution Approach 1:
The patent transitions from a planar two-dimensional layout of semiconductor dies on the lead frame to a three-dimensional stacked configuration. The controller die is positioned on top of the power switch die, utilizing the vertical dimension to reduce the horizontal package footprint while maintaining manufacturability through modified assembly processes.
Solution Approach 2:
The controller die is placed on top of the power switch die, creating a nested vertical arrangement where one die is positioned atop another. This nesting approach consolidates multiple components into a compact vertical stack, reducing the overall package area while preserving the functional separation of components.
2Ease of manufacture
If separate semiconductor dies are interconnected by wire bonding, then the power converter can be assembled, but interconnection resistance and parasitic inductance increase
Solution Approach 1:
The patent merges the interconnection function into the physical bonding interface between stacked dies. Instead of separate wire bonds connecting separate dies, the dies are directly bonded together, combining the mechanical support and electrical interconnection functions into a single integrated interface that reduces parasitic elements.
Solution Approach 2:
The patent extracts and eliminates the wire bonding interconnection layer from the signal path. By directly bonding the controller die to the power switch die, the unnecessary wire bonds and their associated parasitic resistance and inductance are removed, leaving only the essential electrical connections.
3Ease of manufacture
If multiple semiconductor dies are laid in the same plane, then the assembly process is conventional, but noise interference increases due to larger package size
Solution Approach 1:
The patent uses vertical stacking to separate noisy power switching operations from sensitive control circuitry in the third dimension. The controller die sits atop the power switch die, creating vertical separation that reduces electromagnetic noise coupling while maintaining compact packaging and manageable assembly processes.
Data Source
AI summary
An integrated circuit for implementing a switch-mode power converter is disclosed. The integrated circuit comprises at least a first semiconductor die having an electrically quiet surface, a second semiconductor die for controlling the operation of said first semiconductor die stacked on said first semiconductor die having said electrically quiet surface and a lead frame structure for supporting said first semiconductor die and electrically coupling said first and second semiconductor dies to external circuitry.