Wiring Board Conductive Column Pad Design
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Solution Overview
Problem
Existing wiring boards with conductive blind vias face limitations in increasing wiring density due to the larger size of pads required for alignment, which occupy more surface area and restrict the development of higher density designs.
Innovation Solution
A wiring board design featuring conductive columns that protrude from an insulating layer, connected to a wiring layer, allowing for a smaller pad size and increased density by using a method involving the formation of shade layers, etching, and deposition of conductive material to create recesses and trenches, enabling the columns to serve as pads for external connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive blind vias are used with larger pads for alignment, then alignment reliability is improved, but wiring density is reduced due to increased pad area occupation
Solution Approach 1:
The conductive column extends in the vertical dimension by protruding from the insulating layer surface, transforming a 2D pad layout problem into a 3D structure. This allows the conductive connection to occupy vertical space rather than only horizontal space, enabling smaller pad footprints and higher wiring density while maintaining alignment reliability through the protruding structure's inherent positioning accuracy
Solution Approach 2:
The invention changes the geometric parameters of the conductive structure by making the conductive column protrude above the insulating layer surface. This parameter change allows the pad size to be reduced to match or slightly exceed the conductive column diameter, rather than requiring significantly larger pads for alignment, thereby increasing wiring density while preserving alignment reliability
2Reliability
If larger pads are used to ensure conductive blind via connection, then connection reliability is improved, but surface area occupation increases limiting wiring density
Solution Approach 1:
The conductive column protrudes from the insulating layer surface into the third dimension, allowing the connection structure to utilize vertical space. This enables the pad area to be minimized to just sufficient for alignment, rather than requiring large horizontal area, thus reducing pad area occupation while maintaining connection reliability
Solution Approach 2:
The protruding conductive column serves dual functions: it provides the conductive connection path and simultaneously acts as the pad structure itself. This self-service approach eliminates the need for separate large pad structures, reducing pad area while ensuring reliable connection through the column's own geometric structure
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 enhances wiring density by allowing the conductive columns to function as pads without the need for larger pads, thus accommodating the trend towards higher density in wiring boards while minimizing surface area occupation.
Implementation Method 1
a conductive material is deposited in the recesses and the trenches, so as to form a plurality of first conductive columns in the recesses, and to form a first wiring layer in the trenches
Data Source
AI summary
A wiring board includes an insulating layer, a wiring layer and a plurality of conductive columns. The insulating layer has a first surface and a second surface opposite to the first surface. The wiring layer is disposed in the insulating layer and has a third surface and a fourth surface opposite to the third surface. The insulating layer covers the third surface, and the second surface of the insulating layer is flush with the fourth surface of the wiring layer. The conductive columns are disposed in the insulating layer and connected to the wiring layer. The conductive columns extend from the third surface of the wiring layer to the first surface of the insulating layer, and protrude from the first surface.