Printed Wiring Board Embedding Conductive Posts in Resin Film
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Solution Overview
Problem
Existing printed wiring boards with multi-layer structures face challenges in achieving high flatness due to unevenness caused by locally increased thickness in regions with formed wiring, making it difficult to stack multiple wiring base bodies effectively.
Innovation Solution
A printed wiring board design where conductive posts and wiring are embedded within an insulating resin film, with the wiring and post portions exposed on one surface, and a frame body surrounding the resin film to maintain uniform thickness, along with a manufacturing method involving support plates, plating, and hot pressing of resin powder to form the insulating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wiring is formed on the main surface of wiring base bodies, then electrical connectivity is achieved, but local thickness increase occurs causing surface unevenness
Solution Approach 1:
The wiring and conductive posts are nested within recesses formed in the insulating resin film. The insulating resin is poured into molds that define these recesses, allowing the wiring structures to be embedded rather than protruding, thus maintaining surface flatness while achieving electrical connectivity.
Solution Approach 2:
The insulating resin film is designed with varying local properties: recesses are formed only in regions where wiring and conductive posts are needed, while other regions maintain the standard film thickness. This localized modification allows wiring formation without overall thickness increase in non-critical areas.
2Adaptability or versatility
If multiple wiring base bodies are stacked using random stacking or collective stacking, then multi-layer structure is achieved, but surface unevenness prevents high flatness
Solution Approach 1:
By nesting wiring and conductive posts within recesses in the insulating resin film, the outer surfaces of stacked wiring base bodies remain flush and flat. This embedding approach eliminates protrusions that would otherwise cause surface unevenness when multiple layers are stacked, enabling high-precision multi-layer construction.
3Reliability
If conductive posts extend through the thickness direction to connect wirings, then electrical connection between layers is achieved, but thickness increase in post regions occurs
Solution Approach 1:
Conductive posts are formed within recesses in the insulating resin film, embedding them rather than allowing them to protrude. This nesting approach maintains the electrical connection function while preventing thickness increase in the regions where conductive posts are located.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach curbs the thickness increase in wiring regions, enabling the production of printed wiring boards with improved flatness by embedding conductive posts and wiring within the insulating resin film, allowing for the stacking of multiple layers without significant surface unevenness.
Implementation Method 1
forming the insulating resin film integrally covering the conductive post and the wiring provided on the one surface of the support plate
Data Source
AI summary
In a wiring base body of a printed wiring board, a conductive post including a wiring portion and a wiring are embedded in an insulating resin film. Therefore, even in a region in which a wiring portion is formed, the wiring base body is not increased in thickness. In addition, even in a region in which a wiring is formed, the wiring base body is not increased in thickness. Therefore, it is possible to obtain a printed wiring board having high flatness by stacking a plurality of wiring base bodies and constituting a printed wiring board.