Substrate Opening Layout for Longer Pad Creepage Distance
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Solution Overview
Problem
Electronic devices face issues with metal pads on substrates corroding and ionizing, leading to potential short circuits due to adjacent pads connecting electrically, which can be delayed by increasing the creepage distance between them.
Innovation Solution
The implementation of openings and recesses in the organic compound layer of the substrate, along with a protrusion, to increase the creepage distance between pads and wires, and the use of a cover to protect the pads from corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the creepage distance between adjacent pads is increased to prevent short circuits caused by metal corrosion and ionization, then the reliability of the circuit is improved, but the area occupied by the substrate increases
Solution Approach 1:
The patent introduces openings that penetrate through the organic compound layer in the thickness direction (Z-axis), creating a three-dimensional creepage path. This vertical dimension allows the creepage distance to extend through the opening depth rather than only along the substrate surface, effectively increasing the electrical insulation path without proportionally increasing the substrate footprint area.
Solution Approach 2:
The openings are positioned to extend between adjacent pads, creating a nested structure where the opening is embedded within the organic compound layer. This nested configuration allows the creepage path to utilize the opening space efficiently, maximizing the insulation distance within the available substrate volume.
2Reliability
If openings are introduced in the organic compound layer to increase creepage distance, then the resistance against metal ionization is improved, but the structural complexity of the substrate increases
Solution Approach 1:
The organic compound layer is segmented by introducing openings that divide it into regions around the openings. This segmentation creates distinct insulating zones that force the metal ions to navigate a longer, more complex path between adjacent pads, thereby increasing resistance against short circuits while maintaining a relatively simple overall substrate structure.
3Duration of action of stationary object
If the creepage distance is extended through openings and recesses, then the product lifetime is extended, but the manufacturing precision requirements increase
Solution Approach 1:
The openings and recesses are strategically positioned in specific locations where they provide maximum creepage distance enhancement. Rather than uniformly distributing complex features across the entire substrate, the design concentrates the structural modifications in critical areas between adjacent pads, thereby extending product lifetime while limiting the overall manufacturing precision burden to specific localized regions.
Data Source
AI summary
According to one embodiment, an electronic device includes a wall and a substrate. The substrate is provided with an opening. The substrate includes an organic compound layer, a first surface of the organic compound layer, a second surface of the organic compound layer opposite the first surface, first wiring on the second surface, second wiring on the second surface, a first pad, and a second pad. The first surface is attached to the wall. The first pad is connected to the first wiring. The second pad is connected to the second wiring away from the first pad. The opening penetrates the organic compound layer to open to the first surface and the second surface between the first pad and the second pad.