Protective Layered Circuit Board for Fine Pattern Stability
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Solution Overview
Problem
Conventional circuit boards with fine circuit patterns face issues of deformation and collapse due to external impacts, especially in high-frequency applications like 5G communication systems, where the outermost circuit patterns lack sufficient support and are prone to reliability problems.
Innovation Solution
A circuit board design featuring a protective layer with varying heights and surface roughness to support the outermost circuit patterns, minimizing deformation and enhancing reliability, using a method that avoids sandblasting or plasma methods to maintain pattern integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the circuit pattern line width is reduced to increase circuit integration, then the degree of circuit integration is improved, but the circuit pattern becomes more susceptible to deformation and collapse
Solution Approach 1:
The protective layer is applied selectively only to the outermost circuit pattern, creating different protective properties for different regions of the circuit board. This localized protection approach allows the inner circuit patterns to maintain fine line widths for high integration while providing enhanced support specifically where needed for the vulnerable outermost pattern, resolving the contradiction between circuit integration and pattern stability.
2Loss of energy
If the outermost circuit pattern is made finer to reduce transmission loss, then transmission loss is reduced, but the pattern becomes more prone to collapse due to external impacts
Solution Approach 1:
A protective layer is applied in advance to the outermost circuit pattern before the board undergoes assembly and usage. This protective layer acts as a cushion that absorbs external impacts and prevents the fine outermost circuit pattern from collapsing, allowing the pattern to be made finer for reduced transmission loss without sacrificing mechanical strength.
3Force
If sandblasting or plasma methods are used to form the protective layer, then the protective layer adheres well to the circuit pattern, but the pattern integrity is compromised due to deformation
Solution Approach 1:
The patent replaces the mechanical/chemical etching methods (sandblasting and plasma) with a coating process where a protective layer material is applied over the circuit pattern. This substitution avoids the deformation caused by aggressive surface treatment while still achieving strong adhesion between the protective layer and the circuit pattern through controlled coating and curing processes.
Data Source
AI summary
A circuit board according to an embodiment includes an insulating layer; a circuit pattern disposed on the insulating layer; and a protective layer disposed on the insulating layer and the circuit pattern, and including first and second regions having different heights; wherein the circuit pattern includes: a first-first circuit pattern corresponding to the first region of the protective layer; and a first-second circuit pattern corresponding to the second region of the protective layer, wherein a height of the first region of the protective layer is lower than a height of the first-first circuit pattern, wherein a height of the second region of the protective layer is higher than a height of the first-second circuit pattern, wherein a surface of the first-first circuit pattern includes: a first portion in contact with the first region of the protective layer, and a second portion excluding the first portion, and wherein a surface roughness Ra of the first portion is different from a surface roughness Ra of the second portion.