Printed Wiring Board Via Seed Layer for Low Transmission Loss
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Solution Overview
Problem
Existing printed wiring boards face challenges in efficiently transmitting high-speed data due to data degradation caused by rough inner wall surfaces of via conductor openings, which affect the reliability and quality of electronic component connections.
Innovation Solution
A printed wiring board design featuring a resin insulating layer with smooth inner wall surfaces formed by selectively removing protruding inorganic particles, allowing for a seed layer with a smooth first portion and second portion to be formed, which are electrically connected and partially overlapping, enhancing the strength and reducing transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inorganic particles are added to the resin insulating layer to improve mechanical strength and filling density, then the structural integrity is enhanced, but the inner wall surface of via conductor openings becomes rough causing data degradation
Solution Approach 1:
The patent applies local quality by creating a dual-structure inner wall surface: a smooth lower portion (first inner wall surface) that contacts the seed layer to ensure low transmission loss, and a textured upper portion (second inner wall surface) that provides mechanical strength through inorganic particle embedding. This localized differentiation allows each region to fulfill its specific function without compromising the other.
Solution Approach 2:
The inner wall surface is segmented into two distinct portions: the first inner wall surface extending from the bottom opening with smooth morphology, and the second inner wall surface above it with embedded inorganic particles. This segmentation allows the smooth lower portion to ensure electrical connection quality while the upper portion provides structural reinforcement.
2Reliability
If the inner wall surface is made smooth to reduce transmission loss, then data transmission quality improves, but the mechanical strength and filling density of the resin insulating layer decreases
Solution Approach 1:
The patent implements local quality by differentiating the inner wall surface into a smooth lower portion for electrical connection and a textured upper portion for mechanical strength, allowing both requirements to be satisfied in different spatial zones.
Solution Approach 2:
The patent resolves the contradiction by transitioning from a uniform one-dimensional surface property to a two-dimensional differentiated structure, where the inner wall surface has varying morphological characteristics at different heights, enabling simultaneous optimization of electrical and mechanical properties.
3Reliability
If a thick seed layer is formed to ensure complete coverage and electrical connection, then connection reliability improves, but manufacturing complexity and material usage increase
Solution Approach 1:
The patent applies local quality by creating a seed layer with varying thickness: a thicker first seed layer portion that contacts the first inner wall surface to ensure reliable electrical connection, and a thinner second seed layer portion above it. This localized thickness variation reduces overall material usage while maintaining connection reliability.
Solution Approach 2:
The patent uses partial action by forming the seed layer only where electrically necessary - specifically on the first inner wall surface and partially on the second inner wall surface - rather than uniformly coating the entire inner wall, thereby reducing material consumption and manufacturing complexity while maintaining sufficient connection reliability.
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 design achieves low transmission loss and high-quality data transmission by ensuring a smooth seed layer on the inner wall surfaces of via conductor openings, improving the connection reliability and stability of electronic components.
Implementation Method 1
including a seed layer and an electrolytic plating layer formed on the seed layer
Data Source
AI summary
A printed wiring board includes a conductor layer including wirings, a resin insulating layer having openings, a mounting conductor layer including first and second electrodes, first via conductors including a seed layer and an electrolytic plating layer such that the first via conductors connect the first electrodes and the wirings, and second via conductors including the seed layer and electrolytic plating layer such that the second via conductors connect the second electrodes and the wirings. The first electrodes are positioned to mount a first electronic component. The second electrodes are positioned to mount a second electronic component. The first and second via conductors are formed such that the seed layer is covering an inner wall surface of each opening in the insulating layer and has a first portion and a second portion connected to the first portion and having a part of the first portion formed on the second portion.