Wiring Board Direct Bonding Without Insulating Resist Layers
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Solution Overview
Problem
Conventional wiring boards have a thickness issue due to the presence of two insulating resist layers between substrates, which increases their overall thickness and manufacturing costs.
Innovation Solution
A wiring board design that eliminates the need for insulating resist layers by directly connecting two substrates with conductive wirings facing each other, allowing for direct contact and bonding without intermediates, thereby reducing thickness and manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two insulating resist layers are used between substrates, then electrical insulation is ensured, but the wiring board becomes thick
Solution Approach 1:
The patent removes the insulating resist layers from the conventional structure, extracting the problematic component that caused thickness increase. Instead of using separate insulating resist layers, the wiring board utilizes the substrate surfaces themselves for direct contact, eliminating the need for intermediate insulating layers while maintaining electrical insulation through the substrate material properties.
Solution Approach 2:
The patent merges the functions of the substrate and insulating resist by using the substrate surface directly for electrical connection. The first substrate and second substrate are brought into direct pressure contact with each other, combining the structural support function and electrical insulation function into the substrate itself, thereby eliminating the need for separate insulating resist layers.
2Reliability
If two insulating resist layers are used between substrates, then electrical insulation is provided, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts and removes the insulating resist layers from the manufacturing process, significantly simplifying the production steps. By eliminating the need to form, pattern, and bond separate insulating resist layers, the manufacturing process becomes less complex and more cost-effective while maintaining electrical insulation through direct substrate contact.
Solution Approach 2:
The patent combines the substrate fabrication process with the insulation function, eliminating the need for separate insulating resist processing steps. The substrate surfaces are directly prepared and bonded, merging multiple processes into fewer steps and reducing overall manufacturing complexity.
3Length of moving object
If substrates are directly connected without insulating resist layers, then thickness is reduced, but connection strength must be maintained
Solution Approach 1:
The patent applies preliminary surface treatment to the substrate surfaces before bonding, enhancing the connection strength. By preparing the substrate surfaces in advance (through cleaning, activation, or coating), the direct contact between substrates achieves strong adhesion without requiring intermediate insulating layers, thus maintaining connection strength while reducing thickness.
Solution Approach 2:
The patent changes the surface parameters of the substrates to optimize direct bonding. By modifying surface energy, roughness, or chemical composition through treatment processes, the substrates achieve sufficient bonding strength when in direct contact, eliminating the need for insulating resist layers while maintaining connection integrity.
Data Source
AI summary
A wiring board that includes: a first substrate having a first main surface; a second substrate having a second main surface; a first wiring on the first main surface; and a second wiring on the second main surface. The first main surface and the second main surface are in contact with each other, and the first substrate and the second substrate are connected to each other. The first wiring and the second wiring face each other in a thickness direction of the first substrate and are electrically connected to each other.