Wiring Substrate Grid Plane Layer Adhesion
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Solution Overview
Problem
The existing wiring substrates face challenges in maintaining the planar shape of miniaturized wiring layers due to the roughening process, which affects adhesion and leads to potential defoliation of insulation layers, and they struggle with achieving high wiring density while preventing warping and deformation.
Innovation Solution
A wiring substrate design featuring a stacked structure with a grid-shaped plane layer and tapered through holes, where the insulation layer covers the plane layer and wiring layer, and a solder resist layer is used to balance physical values and reduce warping, incorporating a smooth upper surface for improved adhesion and miniaturization of wiring layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a roughening process is performed on the plane layer to increase adhesion, then the adhesion between the plane layer and insulation layer is improved, but the wiring layer cannot maintain the desired planar shape when miniaturized
Solution Approach 1:
The plane layer is divided into a grid pattern with through holes, creating multiple small segments instead of a continuous solid layer. This segmentation reduces the overall roughness impact on wiring layers while maintaining adhesion through the distributed grid structure and tapered through holes that provide mechanical interlocking.
Solution Approach 2:
The grid-shaped plane layer with through holes creates different surface characteristics in different regions. The through holes provide localized adhesion points with tapered shapes that enhance bonding, while the grid openings provide smooth regions that preserve the planar shape of miniaturized wiring layers.
2Manufacturing precision
If the roughening process is omitted to maintain the planar shape of wiring layers, then the manufacturing precision is improved, but the adhesion between the plane layer and insulation layer becomes low causing defoliation
Solution Approach 1:
The continuous plane layer is segmented into a grid pattern with through holes, which maintains the overall planar appearance while creating multiple localized adhesion zones. The segmented structure provides sufficient bonding area without creating excessive roughness that would distort miniaturized wiring layers.
Solution Approach 2:
The plane layer combines a grid-shaped conductive pattern with tapered through holes filled with conductive material, creating a composite structure that provides both mechanical support and electrical connectivity. The tapered through holes enhance adhesion through mechanical interlocking while the grid pattern maintains surface smoothness.
3Productivity
If wiring layers are miniaturized to increase wiring density, then the productivity is improved, but the roughening process greatly changes the shape of the wiring layer
Solution Approach 1:
The grid-shaped plane layer with through holes segments the surface into multiple small regions, allowing miniaturized wiring layers to be formed in each grid cell. This segmentation isolates the wiring patterns from the effects of roughening processes while maintaining high wiring density through the compact grid structure.
Solution Approach 2:
The grid pattern creates localized smooth regions within each grid cell that preserve the shape of miniaturized wiring layers, while the through holes provide localized adhesion enhancement. This local quality differentiation allows high wiring density without sacrificing shape precision.
4Manufacturing precision
If a solid plane layer is formed to ensure flatness, then the manufacturing precision is improved, but the adhesion is insufficient without roughening process
Solution Approach 1:
The solid plane layer is segmented into a grid pattern with through holes, maintaining overall flatness while creating multiple localized adhesion zones. The segmentation provides sufficient bonding area without compromising the flat surface required for precise wiring layer formation.
Solution Approach 2:
The tapered through holes introduce a curved geometric feature that enhances adhesion through mechanical interlocking. The tapered shape creates a wedging effect that improves bonding between the plane layer and insulation layer while maintaining the overall flat surface topology.
Data Source
AI summary
A wiring substrate includes a first wiring structure and a second wiring structure stacked thereon. The first wiring structure includes a first insulation layer and a via wiring extending through the first insulation layer. The second wiring structure includes a first wiring layer formed on the first insulation layer and the via wiring, and a first plane layer stacked on the first insulation layer and at least partially grid-shaped in a plan view to define second through holes. A second insulation layer is stacked on the first insulation layer to fill the second through holes and cover the first plane layer and the first wiring layer. The second wiring structure has a higher wiring density than the first wiring structure. The second through holes each include a lower open end and an upper open end having a smaller open width than the lower open end.