Printed Wiring Board with Coplanar Mounting Pads
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Solution Overview
Problem
Existing printed wiring boards face challenges in mounting semiconductor elements due to voids and surface undulation caused by resin sealing, leading to potential mounting failures and reduced reliability.
Innovation Solution
A printed wiring board design featuring a first resin insulating layer with first mounting pads and a wiring structure with a second resin insulating layer and second conductor pattern, where the second mounting pads are embedded and exposed on the same plane as the first mounting pads, eliminating the need for additional resin sealing and enhancing alignment and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resin sealing is used to embed the wiring structure in the main wiring board, then the wiring structure is sealed inside the main wiring board, but voids and surface undulation occur leading to mounting failures
Solution Approach 1:
The patent extracts the harmful resin sealing process from the manufacturing method. Instead of sealing the wiring structure with resin, the invention exposes the wiring structure on the surface of the main wiring board, eliminating the source of voids and surface undulation while maintaining the electrical connection function
Solution Approach 2:
The patent inverts the conventional approach by not embedding the wiring structure inside the main wiring board with resin, but rather positioning it on the surface. This inversion eliminates the sealing step that causes defects while achieving the same electrical connection purpose
2Manufacturing precision
If the second mounting pads are embedded in the second resin insulating layer, then the mounting surfaces of the first and second mounting pads are formed on the same plane, but additional resin sealing is required
Solution Approach 1:
The patent removes the resin sealing process from the manufacturing steps. The second mounting pads are embedded in the second resin insulating layer without requiring additional sealing resin, simplifying the device structure and manufacturing process while maintaining precise alignment
Solution Approach 2:
The second resin insulating layer serves multiple functions: it provides electrical insulation, supports the second conductor pattern, embeds the second mounting pads, and eliminates the need for separate sealing resin. This multi-functionality reduces device complexity
Data Source
AI summary
A printed wiring board includes a first resin insulating layer, a first conductor pattern including first mounting pads formed on the first resin insulating layer, and a wiring structure positioned on the first resin insulating layer and including a second resin insulating layer and a second conductor pattern such that the second resin insulating layer and second conductor pattern are positioned adjacent to the first conductor pattern and that the second conductor pattern includes second mounting pads. The second mounting pads are embedded in the second resin insulating layer such that the second mounting pads have mounting surfaces exposed on an exposed surface of the second resin insulating layer, and the first mounting pads have mounting surfaces such that the mounting surfaces of the first and second mounting pads are formed on a same plane.