Foldable Redistribution Layer with Compliant Support
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Solution Overview
Problem
Existing microelectronic packaging technologies face challenges in compacting multiple chips and dies into small spaces while maintaining structural integrity, as conventional redistribution layers (RDLs) are brittle and prone to cracking under mechanical stresses from bending and folding.
Innovation Solution
A microelectronic assembly comprising a redistribution layer (RDL) coupled with a compliant layer, which mitigates mechanical stresses by redistributing connections and allowing the RDL to be bent or folded, featuring interlocking surfaces and additional compliant layers for structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional rigid redistribution layers are used to maintain structural integrity, then strength is improved, but the ability to bend and fold without cracking deteriorates
Solution Approach 1:
The patent replaces conventional rigid redistribution layers with flexible thin-film circuits that can be bent and folded without cracking. These thin-film circuits are deposited on flexible substrates, enabling the microelectronic assembly to achieve compact folded configurations while maintaining electrical connectivity and structural integrity throughout the bending process.
Solution Approach 2:
The patent employs composite structures combining flexible substrates with thin-film circuit layers. This composite approach integrates the mechanical flexibility of the substrate with the electrical functionality of the thin-film circuits, creating a redistribution layer system that simultaneously achieves both bendability and structural integrity.
2Volume of moving object
If multiple chips and dies are packed into a small space to reduce device size, then volume is reduced, but mechanical stress and cracking risk increase
Solution Approach 1:
The flexible thin-film circuits enable the microelectronic assembly to be folded into compact configurations, dramatically reducing the volume occupied by multiple chips and dies. The flexibility of the thin-film structure allows these compact folded arrangements to be achieved without introducing excessive mechanical stress that would cause cracking, thus maintaining reliability while minimizing device size.
3Reliability
If rigid redistribution layers are used to maintain electrical connectivity, then electrical conductivity is preserved, but mechanical flexibility deteriorates
Solution Approach 1:
The patent uses thin-film circuit technology to create flexible electrical interconnections. These thin-film circuits maintain reliable electrical connectivity between multiple chips and dies while possessing the inherent flexibility needed for bending and folding applications. The thin-film structure prevents signal propagation issues that would otherwise occur in rigid structures subjected to mechanical deformation.
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
Enables the formation of compact, foldable microelectronic assemblies that can be bent or folded without cracking, maintaining electrical connectivity and reducing mechanical stress, thus facilitating high-speed operation and compact device design.
Implementation Method 1
a compliant layer coupled to the RDL between the first portion and the second portion, the compliant layer partially extending into the first portion and partially extending into the second portion
Data Source
AI summary
A foldable microelectronic assembly and a method for forming the same are provided. One or more packages comprising encapsulated microelectronic elements are formed, along with a compliant layer. The packages and the compliant layer are coupled to a redistribution layer. The compliant layer and the redistribution layer are bent such that the redistribution layer is non-planar.