PCB Via Pad Roughness for Coupling Strength
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Solution Overview
Problem
There is a growing demand for small and thin printed circuit boards with efficient via hole processing techniques that achieve excellent electrical and mechanical properties, as existing methods fail to adequately address the need for high coupling strength between vias and pads in miniaturized devices.
Innovation Solution
A printed circuit board design featuring a via hole with a center pad portion that has higher roughness than the peripheral portions, formed using a sandblasting process to increase coupling strength, and filled with metal to connect vias to the pad, allowing for improved interlayer connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional via hole processing techniques are used in thin printed circuit boards, then manufacturing is simplified, but coupling strength between vias and pads deteriorates
Solution Approach 1:
The sandblasting process selectively roughens only the center portion of the pad surface where the via will be connected, while leaving peripheral portions smooth. This localized surface treatment increases coupling strength at the critical via-pad interface without requiring complex processing of the entire pad area, thus resolving the contradiction between improved strength and reduced processing complexity.
2Volume of moving object
If the printed circuit board is miniaturized and thinned, then device size is reduced, but via formation and coupling become more difficult
Solution Approach 1:
The sandblasting process changes the surface parameter (roughness) of the pad center portion, creating a textured surface that significantly enhances coupling strength. This parameter change allows thin and miniaturized boards to achieve adequate via-pad coupling without increasing board thickness or size, as the surface roughness compensation enables reliable connections in compact geometries.
3Strength
If the center portion of the pad is roughened, then coupling strength is improved, but manufacturing precision requirements increase
Solution Approach 1:
The sandblasting process uses abrasive particles that automatically adapt to the pad surface geometry, creating uniform roughness across the center portion without requiring precise control of blasting parameters. The process self-regulates to produce consistent surface texture, reducing manufacturing precision requirements while achieving the desired coupling strength improvement.
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
The solution enhances the coupling strength between vias and pads, improving the electrical and mechanical properties of the printed circuit board, particularly in miniaturized devices, by increasing the surface area for better connection and reducing signal loss.
Implementation Method 1
selectively removing the insulating layer using a sandblasting process to form a via hole exposing a center portion of the pad such that the center portion of the pad has a higher roughness than peripheral portions of the pad
Data Source
AI summary
A printed circuit board includes: an insulating layer having a via hole formed therein; a single layer metal pad disposed in the insulating layer and having a center portion that is exposed by the via hole, the center portion of the pad having a higher roughness than peripheral portions of the pad; and a via formed in the via hole and connected to the center portion of the pad.