Wiring Substrate Curved Conductor Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multilayer wiring boards face issues with interfacial peeling and adhesion strength between conductor layers and insulating layers, particularly due to surface unevenness and solder diffusion, which affect the reliability and quality of the board.
Innovation Solution
The wiring substrate incorporates a core layer with multiple conductor layers and interlayer insulating layers, where at least one inner and outer conductor layer has a first laminated structure with a metal foil and plating film, and intermediate conductor layers have a second laminated structure with a thinner metal foil layer, featuring side surfaces that curve inward or outward to enhance adhesion and reduce peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conductor layers are formed with conventional flat structures, then manufacturing is simple, but adhesion strength between conductor layers and insulating layers is insufficient causing interfacial peeling
Solution Approach 1:
The conductor layers are designed with curved side surfaces instead of flat surfaces. The inner conductor layer has a side surface curving toward the inner side, while the outer conductor layer has a side surface curving toward the outer side. This curvature creates an interlocking effect with the insulating layers, significantly improving adhesion strength and preventing interfacial peeling.
Solution Approach 2:
The wiring substrate employs a composite structure combining conductor layers with insulating layers in a multilayer configuration. The alternating arrangement of conductor and insulating layers with the curved interface geometry creates a composite material system that leverages the complementary properties of conductive and insulating materials while enhancing interfacial bonding.
2Reliability
If solder diffusion is not controlled, then manufacturing is easier, but electrical connection reliability deteriorates
Solution Approach 1:
The curved side surfaces of the conductor layers serve as physical barriers that control solder diffusion. The inward curvature of the inner conductor layer and outward curvature of the outer conductor layer create geometric constraints that limit the spread of solder, ensuring reliable electrical connections while maintaining controlled diffusion boundaries.
Data Source
AI summary
A wiring substrate includes a core layer, first conductor layers including first inner, outer and intermediate conductor layers, second conductor layers including second inner, outer and intermediate conductor layers, and interlayer insulating layers interposed between the first conductor layers and between the second conductor layers. The first and/or second inner conductor layers has a first laminated structure including metal foil and plating film layers and includes first conductor pattern having a side surface curved toward inner side of the first pattern, the first and/or second outer conductor layers has the first laminated structure and includes the first conductor pattern having the side surface curved toward the inner side of the first pattern, and the first and/or second intermediate conductor layers has a second laminated structure including metal foil and plating film layers and includes second conductor pattern having a side surface curved toward outer side of the second pattern.