Pad Electrode Structure for Underlay Resin Stress Relief
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Solution Overview
Problem
Existing electronic components face challenges in managing stress and reliability due to thermal expansion and deformation issues in the wiring and pad structures, leading to potential peeling-off or cracking of underlay resin films.
Innovation Solution
The electronic component design incorporates a wiring electrode with a round upper end corner and a wiring cover electrode that includes a Ni-based metal film, along with an underlay resin film covering the wiring upper end corner, and a pad electrode with a recessed portion or projection, all of which are strategically structured to manage stress and enhance reliability by allowing elastic deformation and stress relaxation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the wiring electrode has a sharp upper end corner, then the manufacturing precision is improved, but the underlay resin film is prone to peeling-off or cracking due to stress concentration
Solution Approach 1:
The upper end corner of the wiring electrode is designed with a rounded shape instead of a sharp corner. This curvature eliminates stress concentration points that would otherwise cause peeling-off or cracking of the underlay resin film, while still maintaining sufficient manufacturing precision through controlled rounding radii
Solution Approach 2:
The underlay resin film is positioned to cover the upper end corner of the wiring electrode in advance, creating a cushioning effect that prevents stress-induced damage before it occurs. This pre-positioned resin layer absorbs and distributes thermal expansion stresses, protecting the electrode structure
2Manufacturing precision
If the wiring electrode is made rigid to maintain shape, then the manufacturing precision is improved, but the thermal expansion stress increases causing deformation
Solution Approach 1:
The radius of curvature at the upper end corner of the wiring electrode is optimized to balance rigidity and stress distribution. By controlling this geometric parameter, the electrode maintains sufficient shape stability for manufacturing while reducing stress concentration that would cause thermal deformation
Solution Approach 2:
The electrode structure incorporates multiple material layers with different thermal expansion coefficients. The wiring electrode may include a base metal layer combined with a stress-relief layer or coating, creating a composite structure that maintains shape precision while accommodating thermal expansion differences
3Device complexity
If the underlay resin film is made thin to reduce size, then the device complexity is reduced, but the stress resistance decreases leading to cracking
Solution Approach 1:
The underlay resin film is designed with variable thickness or enhanced material properties specifically at the region covering the wiring electrode's upper end corner. This local reinforcement provides stress resistance where needed most, while keeping the overall film thin to reduce device complexity
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 design effectively reduces stress-induced deformation and improves the reliability of the electronic component by preventing peeling-off or cracking of the underlay resin film, enhancing the component's thermal stability and performance.
Implementation Method 1
allowing elastic deformation and stress relaxation
Implementation Method 2
allowing elastic deformation and stress relaxation
Implementation Method 3
manage stress and enhance reliability by allowing elastic deformation and stress relaxation
Data Source
AI summary
An electronic component includes an underlay resin, and a pad electrode that has a sidewall located on the underlay resin and an uneven portion formed at a lower end portion of the sidewall.