Microspring Interconnects for Stacked IC Warpage and CTE Stress
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Solution Overview
Problem
Integrated circuits face stress and warpage due to mismatch in the coefficient of thermal expansion (CTE) between stacked substrates, which existing technologies fail to adequately address, leading to potential connection failures and reduced lifespan.
Innovation Solution
The use of coil springs (microsprings) to join integrated circuit components, providing both physical and electrical connections while absorbing horizontal and vertical stresses caused by CTE mismatch and warpage, thereby maintaining connectivity and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid connectors are used to join stacked substrates, then electrical connection is maintained, but stress and warpage from CTE mismatch cause connection failures and reduced lifespan
Solution Approach 1:
The patent applies flexible spring connectors instead of rigid connectors to join stacked substrates. The spring connectors can deform elastically to accommodate stress and warpage caused by CTE mismatch between substrates, while maintaining continuous electrical connection. This flexibility prevents connection failures and extends lifespan without sacrificing electrical integrity.
Solution Approach 2:
The patent transitions from static rigid connectors to dynamic spring connectors that can adapt their shape and position in response to thermal expansion and contraction. The spring connectors absorb mechanical stress through elastic deformation, allowing the system to dynamically respond to CTE mismatch and warpage forces.
2Reliability
If spring connectors are used to absorb stress, then connection lifespan is improved, but device complexity increases
Solution Approach 1:
The patent uses simple spring connector designs that can be manufactured cost-effectively using standard fabrication processes. The spring connectors are relatively simple elastic elements that replace complex rigid connector assemblies with stress compensation mechanisms, achieving reliability improvement without proportionally increasing device complexity.
3Ease of manufacture
If rigid connectors are used, then manufacturing is simpler, but shock resistance is poor leading to connection failures
Solution Approach 1:
The patent employs flexible spring connectors that inherently provide shock absorption through elastic deformation. The spring structure naturally dampens mechanical shocks and vibrations, protecting the electrical connection from shock-induced failures while maintaining ease of manufacture through standard spring fabrication techniques.
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 coil springs effectively absorb thermal expansion mismatch and warpage, significantly increasing the lifespan of connections by up to 16 times compared to rigid connectors, and improving shock resistance, while maintaining electrical integrity and preventing solder bridging.
Implementation Method 1
coil springs (microsprings) to join integrated circuit components, providing both physical and electrical connections while absorbing horizontal and vertical stresses caused by CTE mismatch and warpage
Data Source
AI summary
A method includes depositing solder paste over first contact pads of a first package component. Spring connectors of a second package component are aligned to the solder paste. The solder paste is reflowed to electrically and physically couple the spring connectors of the second package component to the first contact pads of the first package component. A device includes a first package component and a second package component electrically and physically coupled to the first package component by way of a plurality of spring coils. Each of the plurality of spring coils extends from the first package component to the second package component.