PCB Via Structure for Uniform Plating and Heat Dissipation
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Solution Overview
Problem
Conventional printed circuit boards face challenges in uniformly plating large-diameter via holes, leading to restrictions in plating and potential dimple regions that affect reliability and heat dissipation characteristics.
Innovation Solution
A printed circuit board design featuring a via structure with a multi-layered connection portion and pads, where the upper surface of the connection portion is concave and the lower surface is convex, with a seed layer between the via hole and pads, allowing for stable and uniform plating across the via hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large-diameter via hole is filled with metal material to improve heat dissipation and shielding characteristics, then heat dissipation and shielding performance are improved, but plating uniformity deteriorates and dimple regions form
Solution Approach 1:
The via hole filling process is segmented into multiple stages: first forming a connection portion with initial plating, then adding pads that protrude from the via hole surfaces. This segmentation allows different regions to be optimized independently - the connection portion provides structural integrity while the pads ensure uniform plating and electrical connection, eliminating the dimple region problem that occurs when attempting to fill the entire via hole in one step.
Solution Approach 2:
The connection portion is formed first as a preliminary structure before adding the pads. This preliminary action creates a foundation that guides subsequent plating operations, ensuring that the metal material is deposited uniformly. The connection portion acts as a pre-formed template that prevents the formation of dimple regions during the final plating stage.
2Reliability
If the via hole is completely filled with metal material to improve electrical connection, then electrical conductivity is improved, but manufacturing complexity increases due to plating restrictions
Solution Approach 1:
The via structure is segmented into two functional parts: a connection portion that provides structural support and electrical pathway, and pads that provide uniform electrical connection points. This segmentation eliminates the need to completely fill the via hole, simplifying the plating process while maintaining excellent electrical connection. The pads protruding from the via hole surfaces ensure reliable electrical contact without requiring complex plating techniques.
Solution Approach 2:
Different regions of the via structure are given different qualities and functions. The connection portion within the via hole provides structural integrity and electrical pathway, while the pads protruding from the surfaces provide optimized electrical connection points with uniform plating. This local differentiation allows each region to be manufactured with appropriate quality standards, improving ease of manufacture while maintaining high reliability.
3Device complexity
If a conventional via structure is used to simplify design, then device complexity is reduced, but design flexibility is limited
Solution Approach 1:
The via structure is divided into a connection portion and pads, creating a modular design that can be independently optimized. This segmentation provides design flexibility by allowing engineers to adjust the size, shape, and distribution of pads and connection portions based on specific application requirements, while maintaining a relatively simple overall structure. The modular nature enables adaptability without significantly increasing device complexity.
Solution Approach 2:
The via structure with connection portion and pads serves multiple functions simultaneously: structural support, electrical connection, heat dissipation, and shielding. This multi-functionality increases design versatility, allowing the same basic structure to be applied across different applications by simply modifying parameters such as pad size, via diameter, or metal material, without requiring fundamentally different designs.
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 design enables stable plating of large-diameter via holes, improves plating uniformity, enhances reliability, and increases the degree of freedom in design, while effectively shielding interference between circuits and improving heat dissipation characteristics.
Implementation Method 1
a connection portion disposed in the via hole of the insulating layer; a first pad disposed on an upper surface of the insulating layer and an upper surface of the connection portion; and a second pad disposed under a lower surface of the insulating layer and a lower surface of the connection portion
Implementation Method 2
stable and uniform plating across the via hole
Data Source
AI summary
A circuit board according to an embodiment includes: an insulating layer including a through hole and a via disposed in the through hole and wherein the via including a first metal layer on an upper surface of the insulating layer and an inner wall of the through hole; and a second metal layer disposed in the through hole, and the an upper surface of the second metal layer includes a protruding portion that does not overlap an upper surface of the insulating layer in a vertical direction and is located higher than the first metal layer.