Liquid Metal Interconnects for Stress-Tolerant Power Modules
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Solution Overview
Problem
The semiconductor packaging industry faces challenges in achieving efficient and reliable electrical connections in integrated circuits due to issues such as mechanical stress, thermal mismatch, and potential reliability problems in traditional soldered and wire-bonded joints, which are prone to failure under fluctuating thermal conditions.
Innovation Solution
The use of liquid metal interconnects with adhesive, cohesive, and surface tension forces to create flexible connections between semiconductor devices and metal circuit elements, utilizing alloys like gallium, indium, and tin, which transition between solid and liquid phases to accommodate thermal fluctuations and mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional soldered and wire-bonded joints are used, then electrical connections can be established, but reliability deteriorates under fluctuating thermal conditions due to mechanical stress and thermal mismatch
Solution Approach 1:
The patent changes the physical state parameter of the interconnect material from solid to liquid, using liquid metal alloys that remain liquid at operating temperatures. This parameter change eliminates mechanical stress and thermal mismatch issues because liquids can flow and adapt to thermal expansion without generating stress concentrations that cause solder joint failure.
Solution Approach 2:
The patent replaces the mechanical bonding system (solder joints and wire bonds that rely on mechanical attachment) with a liquid metal system that uses surface tension, wetting, and capillary forces to maintain electrical connection. This substitution eliminates the mechanical stress problems inherent in traditional mechanical joining methods.
2Temperature
If traditional solid interconnects are used, then structural stability is maintained, but thermal management capability deteriorates due to higher thermal resistance
Solution Approach 1:
The patent changes the physical state parameter of the interconnect material from solid to liquid, using liquid metal alloys that remain liquid at operating temperatures. This parameter change eliminates mechanical stress and thermal mismatch issues because liquids can flow and adapt to thermal expansion without generating stress concentrations that cause solder joint failure.
Solution Approach 2:
The patent replaces the mechanical bonding system (solder joints and wire bonds that rely on mechanical attachment) with a liquid metal system that uses surface tension, wetting, and capillary forces to maintain electrical connection. This substitution eliminates the mechanical stress problems inherent in traditional mechanical joining methods.
3Reliability
If liquid metal interconnects are used, then thermal management and mechanical flexibility are improved, but containment and prevention of leakage become more difficult
Solution Approach 1:
The patent introduces an intermediary encapsulation layer (such as oxide layers or polymer encapsulants) between the liquid metal and the surrounding environment. This intermediary prevents leakage and uncontrolled spreading of the liquid metal while still allowing it to maintain electrical and thermal contact between components, thus resolving the containment problem without sacrificing the benefits of liquid metal interconnects.
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
The liquid metal interconnects provide enhanced thermal management, increased mechanical flexibility, and extended lifetime, reducing thermal resistance and improving power density by approximately 10% while lowering manufacturing costs by 75% compared to traditional methods.
Implementation Method 1
Adhesive forces, cohesive forces, surface tension forces, capillary forces, viscosity, and/or wetting characteristics enable containment of the liquid metal interface within the contact area
Implementation Method 2
Adhesive forces, cohesive forces, surface tension forces, capillary forces, viscosity, and/or wetting characteristics enable containment of the liquid metal interface within the contact area
Implementation Method 3
Adhesive forces, cohesive forces, surface tension forces, capillary forces, viscosity, and/or wetting characteristics enable containment of the liquid metal interface within the contact area
Implementation Method 4
The first liquid metal material transitions between liquid and solid at a first temperature, and the second liquid metal material is transitions between liquid and solid at second temperature
Data Source
AI summary
The disclosed subject matter relates to liquid metal interconnects for power semiconductor modules. For example, disclosed herein are semiconductor package devices, comprising: a semiconductor device comprising an electrode and/or contact pad; a solid metal circuit element; and a liquid metal interface comprising a liquid metal material. The liquid metal interface can append at least a portion of the solid metal circuit element to at least a portion of the electrode and/or contact pad within a contact area. Adhesive forces, cohesive forces, surface tension forces, capillary forces, viscosity, and/or wetting characteristics enable containment of the liquid metal interface within the contact area. Also disclosed herein are methods of making and use of any of the devices disclosed herein.