Conductive Adhesive Segmentation for IC Thermal Stress
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Solution Overview
Problem
Integrated circuits face thermal stresses due to differing coefficients of thermal expansion between various materials in the IC and packaging, which existing technologies have not adequately addressed.
Innovation Solution
The use of an electrically conductive adhesive in combination with a second adhesive, where the second adhesive provides substantial mechanical coupling between the IC and the substrate, reducing the burden on the electrically conductive adhesive and enhancing its resiliency by segregating into conducting and dielectric portions upon processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrically conductive adhesive is used to establish electrical connection between IC terminals and substrate terminals, then electrical connectivity is achieved, but the adhesive is subjected to high thermal stresses due to coefficient of thermal expansion mismatch
Solution Approach 1:
The patent divides the adhesive function into two separate materials: a first electrically conductive adhesive for establishing electrical connections and a second non-conductive adhesive for providing mechanical coupling. This segmentation allows each adhesive to be optimized for its specific function, with the second adhesive bearing the thermal stress burden while the first adhesive focuses on electrical connectivity with reduced mechanical load.
Solution Approach 2:
The second adhesive acts as an intermediary mechanical coupling layer between the IC and substrate, absorbing thermal expansion stresses and protecting the electrically conductive adhesive from excessive mechanical stress. This intermediary structure allows the conductive adhesive to maintain electrical functionality without being directly subjected to the full burden of thermal mismatch stresses.
2Device complexity
If electrically conductive adhesive provides both electrical connection and mechanical coupling, then fewer materials are needed, but the adhesive resiliency decreases under thermal stress
Solution Approach 1:
The patent segments the adhesive system into two specialized materials: the first electrically conductive adhesive optimized for electrical connectivity and the second non-conductive adhesive optimized for mechanical coupling and stress absorption. This segmentation improves overall system reliability under thermal stress compared to using a single adhesive material that must compromise between electrical and mechanical requirements.
Solution Approach 2:
The patent employs a composite adhesive system where two different adhesive materials work together to provide both electrical and mechanical functions. The first adhesive (conductive) and second adhesive (non-conductive) form a composite structure that leverages the strengths of each material type, achieving better overall performance than either material could provide alone.
3Strength
If more electrically conductive adhesive is used to improve mechanical coupling, then electrical connection is strengthened, but manufacturing cost increases
Solution Approach 1:
The patent segments the mechanical coupling function from the electrical connection function by introducing a second non-conductive adhesive. This allows the first electrically conductive adhesive to be applied in smaller, more precise amounts sufficient for electrical connectivity, while the second adhesive provides the bulk of the mechanical coupling. This segmentation reduces the total amount of expensive conductive adhesive required, lowering manufacturing costs while maintaining or improving mechanical strength.
Solution Approach 2:
The patent uses a second non-conductive adhesive that is typically less expensive than the electrically conductive adhesive to provide the primary mechanical coupling function. This allows the more expensive conductive adhesive to be used in smaller quantities, optimizing the cost structure by assigning the bulk mechanical support role to a cheaper material while preserving electrical functionality with the premium conductive material.
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
This solution alleviates thermo-mechanical stresses, reduces the amount of electrically conductive adhesive required, lowers manufacturing costs, and increases the resiliency and performance of the adhesive by transferring mechanical coupling responsibilities to the second adhesive.
Implementation Method 1
the electrically conductive adhesive establishes an electrical connection between each of the one or more integrated circuit terminals and the one or more substrate terminals
Implementation Method 2
a second adhesive in communication with the integrated circuit and the substrate, wherein the second adhesive couples the integrated circuit and substrate together
Data Source
AI summary
A system for packaging integrated circuits includes an integrated circuit having one or more integrated circuit terminals. The system for packaging integrated circuits also includes a substrate having one or more substrate terminals. The system for packaging integrated circuits further includes an electrically conductive adhesive in communication with the integrated circuit terminals and the substrate terminals. The electrically conductive adhesive establishes an electrical connection between each of the one or more integrated circuit terminals and the one or more substrate terminals. The electrical connection between each of the one or more integrated circuit terminals and the one or more substrate terminals are enclosed in a dielectric. The system for packaging integrated circuits includes a second adhesive in communication with the integrated circuit and the substrate, wherein the second adhesive couples the integrated circuit and substrate together.