Via Hole Segmentation for Reduced Capacitance
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Solution Overview
Problem
The excessive electrically conductive material in via holes of circuit boards creates excessive capacitance, leading to impedance discontinuity in signal transmissions between interconnected traces.
Innovation Solution
The solution involves removing excess conductive material from the sidewalls of via holes by forming side-drill-holes, which reduces capacitance and maintains sufficient conductive material for effective interconnectivity, using techniques like drilling or milling to determine the optimal size and position of the side-drill-holes based on the desired width of the remaining conductive material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the via hole is plated with electrically conductive material to ensure sufficient conductive material for interconnectivity, then the reliability of signal transmission is improved, but the via capacitance increases causing impedance discontinuity
Solution Approach 1:
The via hole is segmented into multiple portions: a first portion with electrically conductive material for interconnectivity, a second portion that is removed to reduce capacitance, and a third portion with electrically conductive material for connection. This segmentation allows the via to maintain sufficient conductive material for reliable signal transmission while removing excess material that causes harmful capacitance and impedance discontinuity.
Solution Approach 2:
The patent extracts or removes the excess electrically conductive material from the middle portion of the via hole. By taking out this harmful element (the excess conductive material that creates capacitance), the patent resolves the contradiction between maintaining sufficient conductivity for reliability and reducing harmful capacitance effects.
2Object-generated harmful factors
If the via hole is completely removed to eliminate capacitance, then the via capacitance is reduced, but the interconnectivity between traces is lost
Solution Approach 1:
Instead of completely removing the via hole, the patent segments it into functional portions. The first and third portions with electrically conductive material remain to ensure interconnectivity, while only the middle second portion is removed to reduce capacitance. This segmentation resolves the contradiction by preserving the essential interconnectivity function while eliminating the harmful capacitance.
Solution Approach 2:
The patent applies different qualities to different portions of the via hole: the first and third portions have electrically conductive material for connectivity, while the second portion is removed to reduce capacitance. This local differentiation of quality allows the via to simultaneously achieve both interconnectivity and reduced capacitance.
Data Source
AI summary
The present invention relates to circuit boards and, more specifically, circuit boards with vias (i.e. via holes) exhibiting reduced via capacitance. In one embodiment, the present invention provides a circuit board comprising a first electrically conductive trace, a second electrically conductive trace, a via hole including electrically conductive material thereon, and a coupling element that electrically connects the first trace to the second trace. The coupling element comprises a segment of the via hole that bridges the first trace and the second trace, wherein the via hole segment is a remainder of the via hole after removal of a portion of the via hole.