Etched Leadframe for III-Nitride Rectifier Package
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Solution Overview
Problem
Conventional package integration techniques for combining III-nitride transistors with silicon diodes often negate the benefits of III-nitride transistors by increasing package form factor, manufacturing costs, and thermal dissipation requirements, and are not suitable for high voltage applications due to the need for wire bonds.
Innovation Solution
A high voltage cascoded III-nitride rectifier package is fabricated using an etched leadframe, which allows for wire-bondless surface mounting and mechanical support, enabling efficient assembly and integration of III-nitride transistors with silicon diodes in a compact package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonds are used for terminal connections in conventional package designs, then electrical connections can be established, but package form factor increases, manufacturing costs increase, parasitic inductance and resistance increase, and thermal dissipation requirements increase
Solution Approach 1:
The patent extracts and eliminates the wire bond component from the package structure by using an etched leadframe that provides direct electrical connections. The leadframe is etched to create conductive traces that replace the need for separate wire bonds, thereby reducing package footprint while maintaining electrical connection reliability
Solution Approach 2:
The etched leadframe serves as an intermediary structure that combines both mechanical support and electrical connection functions. Instead of using separate wire bonds for electrical connections, the leadframe itself is patterned with conductive traces that provide both structural integrity and electrical pathways, eliminating the need for additional wire bonds
2Reliability
If conductive clips are used instead of wire bonds to provide high performance package terminals, then parasitic inductance and resistance are reduced, but the requirement to separately form and place the conductive clips precludes processing multiple packages in a single pass
Solution Approach 1:
The patent merges the functions of electrical connection and mechanical support into a single etched leadframe structure. The leadframe is patterned with conductive traces that provide electrical connections while also serving as the mechanical package structure, eliminating the need for separate conductive clip formation and placement steps
Solution Approach 2:
The etched leadframe serves multiple functions simultaneously: it provides mechanical support for the semiconductor device, creates electrical connections through its conductive traces, and enables thermal management pathways. This multi-functionality eliminates the need for separate components like wire bonds or conductive clips, allowing for streamlined single-pass processing
3Ease of manufacture
If conventional package integration techniques are used to combine III-nitride transistors with silicon diodes, then device assembly can be achieved, but the benefits of III-nitride transistors are negated due to increased package form factor, manufacturing costs, and thermal dissipation requirements
Solution Approach 1:
The patent transitions from a conventional wire-bonded three-dimensional package structure to a planar etched leadframe design. The electrical connections are created through two-dimensional conductive traces etched into the leadframe plane, reducing the vertical height and overall package volume while improving thermal pathways to the substrate
Data Source
Figure 1
Figure 2A~2D
Figure 2E~2I
AI summary
Some exemplary embodiments of high voltage cascoded III-nitride semiconductor package with an etched leadframe have been disclosed. One exemplary embodiment comprises a III-nitride transistor having an anode of a diode (220) stacked over a source of the III-nitride transistor (230), and a leadframe (212) that is etched to form a first leadframe paddle portion coupled to a gate of the III-nitride transistor and the anode of the diode, and a second leadframe paddle portion coupled to a drain of the III-nitride transistor. The leadframe paddle portions enable the package to be surface mountable. In this manner, reduced package footprint, improved surge current capability, and higher performance may be achieved compared to conventional wire bonded packages. Furthermore, since multiple packages may be assembled at a time, high integration and cost savings may be achieved compared to conventional methods requiring individual package processing and externally sourced parts.