Microspring Laminate Embedding for Handling Strength
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Solution Overview
Problem
Microsprings are susceptible to breaking due to mechanical stress and handling, and they require special precautions, with thicker springs being brittle and thinner ones lacking sufficient counterforce to penetrate oxide layers, while current protective methods like photoresist are costly and not compatible with high-temperature processes.
Innovation Solution
A laminate structure is applied over the microspring, embedding a portion and exposing the tip, providing structural support, gap protection, and moisture barrier, which can be removed for contact, and is compatible with processing steps like soldering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If thicker microsprings are used to provide sufficient counterforce to penetrate oxide layers, then the contact force is improved, but the springs become more brittle and susceptible to breaking
Solution Approach 1:
A laminate structure is applied over the microspring array before final assembly, embedding the microsprings and providing mechanical support. This laminate acts as a cushioning matrix that prevents the microsprings from breaking during handling while allowing them to maintain sufficient contact force for penetrating oxide layers.
Solution Approach 2:
The solution combines the microspring material (metal or metal alloy) with a laminate material to create a composite structure. The laminate provides mechanical support and reduces brittleness, while the microspring material maintains electrical conductivity and spring properties, creating a composite system that overcomes the limitations of either material alone.
2Strength
If thinner microsprings are used to reduce brittleness, then the spring flexibility is improved, but they lack sufficient counterforce to penetrate oxide layers
Solution Approach 1:
The laminate structure is applied beforehand to provide a supportive matrix that enables thinner, more flexible microsprings to function effectively. The laminate prevents breakage during handling while the microsprings maintain adequate contact force for oxide penetration through their elastic properties.
Solution Approach 2:
The invention changes the physical state and supporting environment of the microsprings by embedding them in a laminate structure. This parameter change allows thinner microsprings to achieve both flexibility and sufficient contact force, as the laminate provides the necessary mechanical support while allowing the microsprings to perform their electrical contact function.
3Strength
If photoresist is used to protect microsprings during handling, then the mechanical protection is improved, but the cost increases and compatibility with high-temperature processes is lost
Solution Approach 1:
The invention changes the material parameter from photoresist (organic, temperature-sensitive) to a laminate material that can withstand high-temperature processes like soldering. This parameter change maintains mechanical protection during handling while achieving compatibility with standard electronic manufacturing processes and reducing overall manufacturing cost.
Solution Approach 2:
The laminate structure serves as a temporary protective matrix that is applied during manufacturing and handling, then removed or left in place depending on the application. This disposable-like approach provides necessary mechanical protection during critical manufacturing stages without requiring expensive photoresist processes or subsequent removal steps.
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 laminate structure enhances the mechanical strength and handling of microsprings, reduces breakage risk, and allows for uniform tip exposure for contact while protecting during processing, maintaining tip integrity and compatibility with various applications.
Implementation Method 1
The microspring is formed from a stress-engineered metal film (i.e., a metal film fabricated to have a stress differential such that its lower portions have a higher internal compressive stress than its upper portions)
Implementation Method 2
A laminate structure is applied over the microspring, embedding a portion and exposing the tip, providing structural support, gap protection, and moisture barrier
Implementation Method 3
A laminate structure is applied over the microspring, embedding a portion and exposing the tip, providing structural support, gap protection, and moisture barrier
Data Source
AI summary
At least one microspring has applied thereover a laminate structure to provide: mechanical protection during handling and wafer processing, a spring spacer layer, strengthening of the anchor between spring and substrate, provision of a gap stop during spring deflection, and moisture and contaminant protection. A fully-formed laminate structure may be applied over the microspring structure or a partly-formed laminate structure may be applied over the microspring structure then cured or hardened. The tip portion of the microspring may protrude through the laminate structure and be exposed for contact or may be buried within the contact structure. The laminate structure may remain in place in the final microspring structure or be removed in whole or in part. The laminate structure may be photolithographically patternable material, patterned and etched to remove some or all of the structure, forming for example additional structural elements such as a gap stop for the microspring.