Circuit Board IC Chip Warping Reduction via Segmented ACF and Low Shrinkage Resin
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Solution Overview
Problem
Circuit boards using anisotropic conductive films (ACFs) face issues with warping of electronic components due to shrinkage during curing, which can lead to poor electrical connections and vulnerability to dust and moisture ingress.
Innovation Solution
Incorporating separated anisotropic conductive films with a low shrinkage resin film in the gaps between them, which reduces the warping force on electronic components and provides protection against dust and moisture by filling the external gaps, thereby enhancing the reliability of connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single anisotropic conductive film is used to electrically connect the IC chip to the glass substrate, then electrical connection is achieved, but the IC chip warps due to shrinkage during curing
Solution Approach 1:
The patent divides the single anisotropic conductive film into multiple separate anisotropic conductive films arranged in a matrix pattern. This segmentation reduces the continuous shrinkage force that causes warping, as each separate film shrinks independently rather than as a single continuous layer, thereby maintaining electrical connection while reducing IC chip deformation
Solution Approach 2:
The patent introduces a resin film with different shrinkage characteristics (lower shrinkage rate) in specific regions between the anisotropic conductive films. This creates local quality variation where the resin film acts as a buffer zone with reduced shrinkage, counterbalancing the shrinkage forces and preventing IC chip warping while maintaining proper electrical connection areas
2Strength
If the anisotropic conductive film shrinks during curing, then bonding strength is achieved, but dust and moisture can enter the connecting portions
Solution Approach 1:
The patent uses the resin film to fill and seal the gaps between the separate anisotropic conductive films, creating a nested structure where the resin film is positioned within the spaces between the conductive films. This nested configuration provides protective sealing that prevents dust and moisture from entering the connecting portions while maintaining the bonding strength of the ACFs
Solution Approach 2:
The resin film acts as an intermediary material between the anisotropic conductive films and the external environment. It mediates by providing a protective barrier that seals the interface region, preventing harmful factors like dust and moisture from reaching the electrical connections while allowing the ACFs to maintain their bonding function
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 configuration effectively reduces warping of electronic components and protects the connecting portions from dust and moisture, improving the reliability and durability of the circuit board connections.
Implementation Method 1
The anisotropic conductive films include a thermoset resin as an adhesive. When the anisotropic conductive film shrinks during curing, the IC chip may be pulled toward the glass substrate and warped.
Implementation Method 2
The resin film is disposed in at least a portion of a gap between the anisotropic conductive films adjacent to each other between the substrate and the electronic component to fill the portion of the gap facing an outside.
Implementation Method 3
The inter-film member includes at least one resin film and a low shrinkage portion. The low shrinkage portion has cure shrinkage smaller than cure shrinkage of the anisotropic conductive films.
Data Source
AI summary
An array circuit board 11B includes a glass substrate, an IC chip 20, two ACFs 30, and a resin film 32. The IC chip 20 is disposed on the glass substrate. The ACFs 30 are disposed between the glass substrate and the IC chip 20 for electrically connecting the glass substrate and the IC chip 20 together. The ACFs 30 are separated from each other. The resin film 32 is made of resin material having cure shrinkage smaller than the ACFs 30 and disposed to fill a gap between the ACFs 30 adjacent to each other between the glass substrate and the IC chip 20.