PCB Pad with Buried Stepped Structure for Miniaturization
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Solution Overview
Problem
As electronic devices become smaller, the smaller metal posts on printed circuit boards (PCBs) are prone to separation from the PCB, leading to potential loss and failure in circuit functionality.
Innovation Solution
The proposed solution involves designing a printed circuit board with a pad portion that includes a first portion, a second portion buried below the first portion, and an optional third portion protruding above the first portion. The second portion has a wider width than the first portion and a curved side wall, which is buried within the insulating layer, thereby enhancing stability and preventing separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of metal posts is reduced to enable smaller electronic devices, then device miniaturization is achieved, but the metal posts become prone to separation from the printed circuit board
Solution Approach 1:
The pad portion is designed with a multi-layer structure extending in the height direction, creating a stepped configuration. The first pad portion protrudes from the first insulating layer, while the second pad portion is formed in the second insulating layer below the first. This vertical dimensionality change provides mechanical interlocking and anchoring effects, preventing separation while maintaining small footprint dimensions for device miniaturization.
Solution Approach 2:
The pad portion structure implements a nested configuration where the second pad portion is embedded within the second insulating layer beneath the first pad portion. This nested arrangement creates a hierarchical structure that provides progressive mechanical support and anchoring, ensuring the pad portion remains securely attached to the printed circuit board even when miniaturized.
2Reliability
If the pad portion is made wider to prevent separation, then stability is improved, but the overall device footprint increases
Solution Approach 1:
Instead of increasing the horizontal footprint to improve stability, the design transitions to the vertical dimension by creating a stepped pad structure. The first and second pad portions are positioned at different heights, with the second portion embedded in the lower insulating layer. This vertical arrangement provides mechanical stability through layered anchoring while maintaining a compact horizontal footprint suitable for miniaturized devices.
Data Source
AI summary
A printed circuit board according to an embodiment may include an insulating layer; a wiring layer buried in the insulating layer; and a pad portion protruding from the insulating layer in a height direction, in which the pad portion may include a first portion and a second portion disposed below the first portion in the height direction, a width of the second portion may be greater than that of the first portion of the pad portion in a plane direction perpendicular to the height direction, a side wall of the second portion may have a curved shape in the height direction, and the side wall of the second portion may be buried in the insulating layer.