PCB Trace Density via Blind Hole Via Elimination
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Solution Overview
Problem
The manufacturing of printed circuit boards is hindered by the need for a high cost and low distribution density of traces due to the requirement of forming a hole ring surrounding through holes, which is inefficient and costly, especially when the process of forming conductive vias and plated through holes differs.
Innovation Solution
A method involving the formation of blind holes aligned with conductive vias, allowing for the elimination of the hole ring in the second trace layer, and using a process where the first and second copper foil layers are removed before forming the trace layers, enabling improved trace distribution density and reduced manufacturing costs by using laser ablation and electro-plating processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hole ring is formed in the second trace layer surrounding the through hole to align with the conductive via, then the conductive via can be properly aligned, but the distribution density of traces in the second trace layer decreases
Solution Approach 1:
The patent removes the hole ring structure from the second trace layer, extracting the unnecessary element that caused trace distribution density to decrease. By eliminating the hole ring while maintaining proper alignment through alternative means, the patent resolves the contradiction between alignment precision and trace distribution density.
2Reliability
If separate processes are used for forming conductive vias and plated through holes, then different manufacturing requirements can be met, but the manufacturing cost increases
Solution Approach 1:
The patent combines the formation of conductive vias and plated through holes into a single integrated process. By merging these previously separate manufacturing steps, the patent maintains the quality requirements for conductive vias while reducing manufacturing complexity and cost.
3Manufacturing precision
If the outer diameter of the hole ring is made larger than the diameter of the through hole to ensure alignment, then alignment tolerance is improved, but the area occupied by the hole ring increases
Solution Approach 1:
The patent eliminates the hole ring structure entirely, removing the source of the area occupation problem. By taking out the hole ring, the patent resolves the contradiction between alignment tolerance and area occupation, allowing for improved trace distribution density.
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 method enhances trace distribution density and reduces manufacturing costs by eliminating the need for a hole ring in the second trace layer, allowing for more efficient electrical connections and streamlined production.
Implementation Method 1
using laser ablation and electro-plating processes
Implementation Method 2
using laser ablation and electro-plating processes
Data Source
AI summary
A printed circuit board includes a first, second, and third dielectric layers, and a first, second, and third trace layers. The first trace layer and the second trace layer are formed on opposite surfaces of the first dielectric layer. The second dielectric layer is formed on the second trace layer, a first blind hole is defined in the first surface and terminated at a position in the first dielectric layer, a first conductive via is formed in the first blind hole. A second blind hole is formed in the second dielectric layer and the first dielectric layer. A second conductive via is formed in the second blind hole. The third trace layer is electrically connected with the second conductive via. The first trace layer is electrically connected with the second trace layer through the first conductive via and the second conductive via.