Polymer Layer Swelling for Substrate Connection Stress Relief
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Solution Overview
Problem
The challenge lies in effectively connecting and packaging integrated circuits with substrates, such as printed circuit boards, while managing scale differences and minimizing thermo-mechanical stress and reliability issues like corrosion and delamination, especially with advancements that include bump bonding and stacking of chips.
Innovation Solution
A method involving the application of a polymer layer to substrates, allowing it to swell after attachment, which bonds with the substrates and reduces shear forces by filling gaps between them, thereby enhancing adhesion and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If integrated circuits are connected to substrates using conventional bonding methods, then electrical connection is achieved, but thermo-mechanical stress and reliability issues like corrosion and delamination occur
Solution Approach 1:
A polymer layer is introduced as an intermediary material between the integrated circuit and the substrate. This polymer layer absorbs and distributes thermo-mechanical stress, preventing direct stress transfer to the connection elements. The polymer swells to fill gaps and voids, creating a stress-distributing medium that protects the electrical connections from corrosion and delamination while maintaining electrical connectivity.
Solution Approach 2:
The polymer layer undergoes a parameter change by swelling after attachment. This swelling behavior allows the polymer to dynamically adapt its volume and density, filling gaps between the integrated circuit and substrate, and distributing stress more uniformly across the connection interface. This parameter change enhances the mechanical coupling and reduces stress concentration at critical connection points.
2Ease of manufacture
If gaps exist between substrates, then assembly is simplified, but adhesion is reduced and reliability decreases
Solution Approach 1:
The polymer layer serves as a mediator that bridges the gap between substrates. Rather than requiring precise alignment and direct contact, the polymer fills the gap and creates a continuous adhesive pathway. This intermediary material maintains adhesion across the gap, allowing simplified assembly while preserving connection reliability.
Solution Approach 2:
The polymer undergoes swelling after attachment, changing its volume and physical properties. This swelling behavior allows the polymer to dynamically fill gaps that may exist due to manufacturing tolerances or thermal expansion, maintaining continuous adhesion without requiring precision assembly. The parameter change from non-swollen to swollen state ensures reliable adhesion while accommodating assembly variations.
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 swollen polymer layer effectively reduces thermo-mechanical stress and improves the reliability of connections between substrates, protecting against corrosion and delamination, while allowing for efficient electrical contact and system integration.
Implementation Method 1
causing the polymer to swell during or after the attachment
Data Source
AI summary
It is proposed a method of manufacturing an electronic system wherein a first substrate comprising first connection elements on a first surface of the first substrate is provided; a second substrate comprising second connection elements on a first surface of the second substrate is provided; a polymer layer is applied to at least one of the two first surfaces; the first connection elements are attached to the second connection elements; and the polymer layer is caused to swell during or after the attachment.