Printed Wiring Board Via Structure for Strong Seed Layer Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing printed wiring boards face challenges in maintaining the adhesion and integrity of conductor layers due to uneven surfaces and irregularities in the resin insulating layer, leading to potential peeling and poor connectivity between conductor layers.
Innovation Solution
A printed wiring board design featuring a resin insulating layer with inorganic particles forming a smooth inner wall surface and a seed layer with varying thicknesses across different portions, ensuring strong adhesion and connectivity through a via conductor that includes a seed layer and electrolytic plating layer, formed using specific thickness ratios and sputtering techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional seed layer with uniform thickness is formed on the resin insulating layer, then the manufacturing process is simple, but the adhesion strength between the seed layer and resin insulating layer is insufficient due to surface unevenness
Solution Approach 1:
The seed layer is designed with different thicknesses in different regions: a first thickness on the resin insulating layer surface, a second greater thickness in the opening, and a third thickness on the conductor layer. This local variation in thickness provides enhanced adhesion at the interface while maintaining manufacturing feasibility through selective sputtering deposition.
2Stability of the object's composition
If the inner wall surface of the resin insulating layer is rough due to inorganic particles, then the resin insulating layer maintains its structural integrity, but the seed layer formation becomes difficult and adhesion is poor
Solution Approach 1:
The inner wall surface of the opening is engineered to have a smooth finish distinct from the surrounding resin insulating layer. This localized smoothing creates a suitable substrate for precise seed layer deposition and ensures good adhesion, while the overall resin insulating layer maintains its structural integrity with embedded inorganic particles for mechanical strength.
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
Enhances the adhesion strength between the resin insulating layer and the seed layer, reducing peeling and improving the reliability of conductor layer connections, thereby ensuring stable electrical conductivity.
Implementation Method 1
an electrolytic plating layer formed on the seed layer
Implementation Method 2
formed using specific thickness ratios and sputtering techniques
Data Source
AI summary
A printed wiring board includes a first conductor layer, a resin insulating layer having an opening, a second conductor layer including a seed layer and an electrolytic plating layer formed on the seed layer, and a via conductor including the seed layer and the electrolytic plating layer and connecting the first conductor and second conductor layers. The seed layer has a first portion on the surface of the insulating layer, a second portion on an inner wall surface in the opening of the insulating layer, and a third portion on a portion of the first conductor layer exposed by the opening of the insulating layer such that the first portion is thicker than the second portion and the third portion, the second portion has a first film and a second film electrically connected to the first film, and a portion of the first film is formed on the second film.