Self-Healing Metal Structure for Thermal Stress Cracking
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Solution Overview
Problem
Conventional metal structures in semiconductor assemblies are prone to premature cracking or fracture due to mechanical and thermal stresses, leading to reduced functionality or complete failure, especially in environments with temperature cycling, where they fail to provide both mechanical support and superior thermal conductivity.
Innovation Solution
A self-healing metal structure is developed, incorporating a base metal structural component with a phase change material having a lower melting point than the base metal, encapsulated by a protective component. Upon the formation of spatial defects, the phase change material reacts with the base metal to form an intermetallic compound, which occupies the defect, restoring the structure's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal structures are used to provide mechanical support and thermal conductivity, then structural strength and thermal performance are maintained, but the structures are prone to cracking and fracture under mechanical and thermal stresses
Solution Approach 1:
The patent incorporates a phase change material with a lower melting point than the base metal into the structure before operation. This material is positioned to react with the metal if cracking occurs, forming an intermetallic compound that fills and seals the crack. The healing mechanism is pre-positioned and automatically activates when thermal or mechanical stress causes damage, restoring structural integrity without external intervention.
Solution Approach 2:
The patent utilizes a phase change material that undergoes a phase transition at a specific temperature lower than the base metal's melting point. When the base metal approaches its melting point or experiences thermal stress, the phase change material melts and reacts with the metal to form an intermetallic compound. This parameter-based activation allows the structure to self-heal at temperatures below the base metal's failure point, preventing catastrophic cracking.
2Temperature
If the base metal structural component is designed for high thermal conductivity, then heat transfer performance is improved, but the metal becomes more susceptible to thermal stress-induced cracking
Solution Approach 1:
The phase change material acts as an intermediary substance between the base metal structural component and the environment. When thermal stress causes cracking in the high-conductivity metal, this intermediary material melts and reacts to form an intermetallic compound that fills the crack. This mediator prevents the propagation of thermal stress cracks while allowing the base metal to maintain its high thermal conductivity function.
3Duration of action of stationary object
If the phase change material is incorporated to enable self-healing, then durability is enhanced, but the structural complexity increases
Solution Approach 1:
The patent merges the phase change material and the base metal structural component into a single integrated system. The phase change material is incorporated within or adjacent to the metal structure, and both components work together to provide structural support and self-healing functionality. This merging eliminates the need for separate healing mechanisms or external intervention systems, achieving enhanced durability through a unified design.
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 self-healing metal structure effectively repairs cracks and defects, maintaining structural integrity and thermal conductivity, thereby enhancing the durability and performance of metal structures in electronic components and substrates, particularly in power modules and circuit boards.
Implementation Method 1
A phase change material may be provided adjacent at least a portion of the base metal structural component. Upon the presence of a spatial defect in the base metal structural component, the phase change material reacts with the base structural component
Implementation Method 2
the phase change material reacts with the base structural component to form an intermetallic compound to at least partially occupy the spatial defect
Data Source
AI summary
A self-healing metal structure is provided for transferring heat between an electronics component and a substrate. The self-healing metal structure includes a base metal structural component. A phase change material is provided adjacent at least a portion of the base metal structural component. A protective component at least partially encapsulates the phase change material. Upon the presence of a spatial defect in the base metal structural component, the phase change material reacts with the base structural component to form an intermetallic compound to at least partially occupy the spatial defect. The phase change material at least partially encapsulated with the protective component may be disposed within the base metal structural component as a plurality of separate capsules incorporated therein, or the phase change material at least partially surrounds the base metal structural component.