Printed Wiring Board Through Hole Resin Coating
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Solution Overview
Problem
Existing printed wiring boards face issues with dust and foreign substance adhesion to electronic components due to rough inner surfaces of through holes, particularly when reinforcing materials like glass cloth are used, which can lead to functional surface contamination and performance degradation.
Innovation Solution
A printed wiring board design featuring a laminate with alternately laminated resin insulating and conductor layers, including a through hole with a resin coating on its inner wall surface, and a component accommodating cavity with a larger lateral width and smaller depth, formed using a method that involves building up layers, forming a separation groove, and removing build-up layers to create a smooth inner surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a through hole is formed through a laminate containing reinforcing materials like glass cloth to improve mechanical strength, then the mechanical strength is improved, but the inner surface of the through hole becomes rough causing dust and foreign substance adhesion
Solution Approach 1:
A resin coating is applied as an intermediary layer on the inner wall surface of the through hole. This coating mediates between the rough laminate structure (with glass cloth) and the electronic component, preventing direct contact between dust/foreign substances and the component while maintaining the mechanical strength provided by the reinforcing materials.
2Object-affected harmful factors
If the inner surface of the through hole is made smooth to prevent dust adhesion, then dust and foreign substance adhesion is prevented, but the mechanical strength may be compromised
Solution Approach 1:
The through hole structure becomes a composite system combining the laminate (with glass cloth for strength) and the resin coating (for smooth surface). This composite approach allows simultaneous achievement of mechanical strength from the laminate and dust prevention from the coating layer.
3Object-affected harmful factors
If a resin coating is formed on the inner wall surface of the through hole to prevent dust adhesion, then dust and foreign substance adhesion is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The resin coating is applied in advance during the manufacturing process, before the electronic component is mounted. This preliminary action ensures the smooth surface is already in place, simplifying the overall process by integrating the dust prevention measure into the existing manufacturing flow rather than adding a separate post-processing step.
Data Source
AI summary
A printed wiring board includes a laminate including resin insulating layers and conductor layers such that the resin insulating layers and the conductor layers are laminated alternately and that the laminate has a through hole opening to a first surface of the laminate and a component accommodating cavity that accommodates an electronic component and having an opening part formed on a second surface of the laminate on the opposite side with respect to the first surface. The through hole is formed through the laminate such that the through hole is extending to the component accommodating cavity, and the laminate has a resin coating formed on an inner wall surface of the through hole.