Via Conductor Peripheral Thickness Variation for Substrate Surface Control
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Solution Overview
Problem
The challenge is to create a thinner electronic element mounting substrate with improved conductivity and reduced surface unevenness and strength degradation, as existing substrates face issues with overlapping clearances leading to surface unevenness and potential cracking when insulating layers are thinned.
Innovation Solution
The substrate design includes a via conductor with first and second electrical conductor layers, featuring land portions, clearance portions, and peripheral portions that are electrically insulated, with the peripheral portions becoming thinner as they move away from the via conductor, reducing overlap and enhancing deformation flexibility to prevent surface unevenness and strength reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the insulating layers are thinned to reduce substrate thickness, then the substrate thickness is reduced, but surface unevenness increases and strength decreases due to overlapping clearances
Solution Approach 1:
The patent applies local quality by making the peripheral portions of clearance portions have different thicknesses - specifically, the thickness varies to become thinner toward the outer periphery. This local variation in thickness allows the substrate to deform and absorb thickness variations at critical locations, preventing surface unevenness and maintaining strength even when insulating layers are thinned overall.
2Reliability
If clearances are provided between land patterns to improve insulation, then insulation property is improved, but surface unevenness increases and cracking risk increases when clearances overlap
Solution Approach 1:
The patent makes the thickness of peripheral portions of clearance portions vary locally - specifically thinner toward the outer periphery. This local thickness variation allows deformation and absorption of thickness variations at clearance locations, preventing surface unevenness and cracking while maintaining the necessary insulation properties.
3Reliability
If clearances overlap in top view to maintain electrical insulation, then insulation is maintained, but surface unevenness increases and strength decreases
Solution Approach 1:
The patent applies local quality by varying the thickness of peripheral portions of overlapping clearance portions - making them thinner toward the outer periphery. This local thickness variation enables the substrate to deform and absorb thickness variations at overlap locations, preventing surface unevenness and maintaining strength while preserving electrical insulation through the clearance structure.
Data Source
AI summary
An electronic element mounting substrate includes a substrate including a first layer, a second layer located on a lower surface of the first layer, and a third layer located on a lower surface of the second layer, and on which an electronic element is to be mounted. The substrate has a via conductor that passes through the first layer to the third layer in a vertical direction. The substrate includes respective electrical conductor layers located between the respective layers and connected to the via conductor in a plan perspective. Each electrical conductor layer includes a land portion surrounding the via conductor, a clearance portion surrounding the land portion, and a peripheral portion surrounding the clearance portion and electrically insulated from the land portion with the clearance portion interposed between the land portion and the peripheral portion. The first land portion has, in a plan perspective, a first portion overlapping the second land portion, and the first clearance portion has, in a plan perspective, a second portion not overlapping the second clearance portion. The first peripheral portion and the second peripheral portion each have, in a vertical cross-sectional view, an end portion that becomes thinner as a distance from the via conductor increases.