Liquid Phase Power Connects for High-Temperature Reliability
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Solution Overview
Problem
Wire bond interconnects in power circuit packages face limitations due to high inductance parasitics, mechanical fatigue, and reliability issues, especially in high-temperature environments, which restrict switching frequencies and long-term reliability, and are inadequate for advanced wide bandgap power devices.
Innovation Solution
The introduction of liquid phase power connects (LPPCs) that transition from liquid to solid and back to relieve stress, offering ultra-low inductance and self-healing properties, enabling reliable operation beyond 250°C with multi-directional cooling and extended reliability up to 20 years.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If wire bond interconnects are used in power circuit packages, then electrical connections can be established, but inductance parasitics increase and switching frequencies are limited
Solution Approach 1:
The patent removes the wire bond interconnect from the power circuit package, replacing it with a low-inductance interconnect structure that is directly integrated into the package substrate. This extraction of the problematic wire bond element eliminates the source of inductance parasitics while maintaining electrical connection functionality.
Solution Approach 2:
The patent transitions from traditional wire bond interconnects to a planar, low-inductance interconnect structure that utilizes the package substrate surface. This dimensional change from three-dimensional wire bonding to two-dimensional planar routing reduces current loop area and associated inductance, enabling higher switching frequencies.
2Power
If wire bond interconnects are used to carry high current, then power transmission is achieved, but mechanical fatigue and reliability issues occur
Solution Approach 1:
The patent merges the interconnect function with the package substrate by integrating low-inductance interconnect traces directly into the substrate structure. This consolidation eliminates separate wire bonds that are susceptible to mechanical fatigue, creating a more reliable current path that is structurally integrated into the package.
Solution Approach 2:
The patent employs composite interconnect structures that combine conductive materials with mechanically robust substrate materials. This composite approach provides both high current carrying capacity and enhanced mechanical reliability, eliminating the fatigue problems associated with pure metal wire bonds.
3Temperature
If wire bond interconnects are used in high-temperature environments, then electrical connections are maintained, but thermal stress causes fracture and failure
Solution Approach 1:
The patent implements localized thermal management and stress distribution features in the interconnect structure. By designing the low-inductance interconnect to have specific geometric characteristics and material properties at critical locations, the structure can withstand thermal expansion and contraction stresses in high-temperature environments without fracturing.
Solution Approach 2:
The patent creates a dynamic interconnect structure that can adapt to thermal stress through flexible routing and compliant mounting. The low-inductance interconnect design incorporates elements that can flex and deform elastically under thermal stress, preventing permanent damage while maintaining electrical connectivity at elevated temperatures.
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
LPPCs significantly improve switching speed, power density, and reliability of power electronics, enabling high-temperature operation with efficiencies greater than 99% and extending the lifetime of power modules beyond current standards.
Implementation Method 1
an interconnect is provide that changes phases from liquid to solid and back to relieve stresses built up due to thermal cycling
Data Source
AI summary
The present invention is directed to a liquid and solid phase power connect for packaging of an electrical device using a using a phase changing metal. The phase changing metal transitions back and forth between a liquid phase and a solid phase while constantly maintaining connection to the electrical device. The packaging uses a substrate, a restraining housing, and a lid to encase an electrical contact on the electrical device and restrain the phase changing metal. In one embodiment, the entire electrical device is encased and a voltage isolator is utilized to limit the contact areas between the phase changing metal and the electrical device. A method for relieving contact stress by transitioning the phase changing metal from a solid to a liquid is also taught.