Multilayer Circuit Board Vias for Low-Loss Reliable Interlayer Connections
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Solution Overview
Problem
Existing multilayer circuit boards face challenges in achieving reliable connections between interlayer connection conductors with small diameters and narrow pitches, leading to potential connection failures.
Innovation Solution
The multilayer circuit boards incorporate interlayer connection conductors with a dual-portion structure, where one portion is a plated via made of copper and the other is a paste via comprising an alloy or composite material with a resin, ensuring strong bonding across conductor layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the diameter of interlayer connection conductors is reduced to shorten current path and reduce insertion loss, then insertion loss is reduced, but connection reliability deteriorates because conductive paste is less likely to fill small holes in the depth direction
Solution Approach 1:
The interlayer connection conductor is divided into two distinct portions: a first portion (plated via) that fills the hole from the surface and a second portion (paste via) that fills the remaining depth. This segmentation allows each portion to be optimized independently - the plated via ensures complete hole filling and reliable electrical connection, while the paste via provides mechanical strength and structural integrity, thereby maintaining connection reliability even as the overall conductor diameter is reduced to minimize insertion loss.
Solution Approach 2:
The interlayer connection conductor uses a composite structure combining two different materials: a metal-based plated via material for the first portion and an alloy or composite paste material for the second portion. This composite approach leverages the advantages of both materials - the plated via provides excellent electrical conductivity and complete hole filling, while the paste via provides mechanical strength and adhesion, enabling reliable connections in small-diameter conductors that would otherwise be difficult to fill completely with paste alone.
2Loss of energy
If the pitch between interlayer connection conductors is reduced to shorten current path, then insertion loss is reduced, but manufacturing precision deteriorates because it becomes difficult to fill holes completely at narrow pitches
Solution Approach 1:
The connection conductor is segmented into a first portion (plated via) that addresses the hole filling requirement and a second portion (paste via) that provides structural support. This segmentation enables complete hole filling even at narrow pitches where paste alone would be insufficient, while maintaining the benefits of reduced pitch for minimizing insertion loss.
Solution Approach 2:
The plated via acts as an intermediary structure that bridges the gap between the surface and the paste via. It provides a reliable conductive path and mechanical anchor that enables complete hole filling at narrow pitches, facilitating precise manufacturing while maintaining the electrical performance benefits of reduced pitch for lowering insertion loss.
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 configuration enhances connection reliability between interlayer connection conductors and conductor layers, even at small diameters and narrow pitches, improving manufacturing efficiency and reducing insertion loss.
Implementation Method 1
a first via (31A) made of a plated via
Implementation Method 2
a second via (31B) made of a paste via including an alloy or a composite material
Data Source
AI summary
A multilayer circuit board includes an insulating base including insulating layers, and first and second main surfaces facing each other in a stacking direction, conductor layers between the insulating layers, or on the first main surface, or on the second main surface, interlayer connection conductors penetrating at least one of the insulating layers, a mounting electrode on the first main surface, and a radiation electrode located closer to the second main surface than the mounting electrode. The conductor layers include first, second, third, and fourth conductor layers each including Cu foil. The interlayer connection conductors include one or more first interlayer connection conductors sandwiched between the first and second conductor layers in the stacking direction, and one or more second interlayer connection conductors sandwiched between the third and fourth conductor layers. in the stacking direction.