PCB Trench Structure to Prevent Copper Migration Shorts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing demand for high-performance, compact electronic products has led to finer conductive patterns on printed circuit boards, which results in issues such as copper migration and electric short-circuits due to reduced intervals between conductive patterns, compromising reliability and requiring design changes in manufacturing.
Innovation Solution
The implementation of a printed circuit board design featuring trenches with uneven surfaces between conductive patterns, increasing the effective interval and preventing copper migration, thereby enhancing reliability without altering the design or manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the interval between conductive patterns is reduced to achieve finer patterns and compact size, then the compact size and integration are improved, but copper migration and electric short-circuits occur compromising reliability
Solution Approach 1:
The invention transitions from a two-dimensional planar separation to a three-dimensional vertical separation by forming trenches between adjacent conductive patterns. This dimensional change allows the conductive patterns to be closer in the horizontal plane (improving compactness) while maintaining electrical isolation through the vertical trench structure, thus preventing copper migration and short-circuits.
Solution Approach 2:
The trench structure acts as an intermediary barrier between adjacent conductive patterns. By introducing this intermediate structure filled with dielectric material, the invention prevents direct interaction between copper from adjacent patterns, thereby eliminating copper migration and short-circuit paths while allowing closer spacing of conductive patterns.
2Reliability
If trenches with uneven surfaces are formed between conductive patterns, then the effective interval is increased and copper migration is prevented, but the device complexity increases
Solution Approach 1:
The invention applies local quality by creating uneven surfaces specifically at the bottom of trenches between conductive patterns, while other areas maintain standard planarity. This localized modification increases the effective interval and copper migration resistance only where needed, without requiring complex modifications throughout the entire PCB structure.
Solution Approach 2:
The uneven surface at the trench bottom introduces curvature and irregularity to the otherwise planar interface. This curved/irregular geometry increases the effective interval and makes it more difficult for copper to migrate across the trench, providing enhanced reliability without requiring uniformly complex structures throughout.
Data Source
AI summary
A printed circuit board includes a substrate body, first, second, and third upper conductive patterns side by side in a first direction on a top surface of the substrate body, and a photosensitive dielectric layer that at least partially covers the top surface of the substrate body. A first trench is in the substrate body between the first and second upper conductive patterns. The first trench has a first surface roughness at a bottom surface thereof. The substrate body has a second surface roughness at the top surface thereof between the second and third upper conductive patterns. The first surface roughness is greater than the second surface roughness. Each of the first and second upper conductive patterns has a first thickness. The third upper conductive pattern has a second thickness greater than the first thickness.