Printed Circuit Board Pad Structure for Stronger Insulating-Layer Bonding
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Solution Overview
Problem
There is a need to enhance the coupling force between pads and insulating layers in printed circuit boards to improve reliability and signal connectivity, particularly in light, thin, and short mobile devices.
Innovation Solution
A printed circuit board design featuring a pad with protruding upper and side surface portions covered by a metal layer, and a via with a concave area on the pad to increase contact area, along with a metal layer filling the gap between the pad and insulating layer, enhancing bonding force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pad is embedded in the insulating layer with protruding surfaces, then the coupling force between pad and insulating layer is improved, but the manufacturing complexity increases
Solution Approach 1:
The pad structure employs curved surfaces instead of flat surfaces, with the upper surface having a first curvature radius and the side surface having a second curvature radius. This curvature design increases the contact area between the pad and insulating layer, thereby improving coupling force and reliability while managing the complexity through geometric optimization.
Solution Approach 2:
The invention uses a metal layer covering the pad surfaces to enhance the coupling force between the pad and insulating layer. This composite structure combines the electrical conductivity of metal with the mechanical bonding properties, creating a more reliable connection that addresses the reliability improvement need.
2Reliability
If the metal layer covers the pad surfaces, then the coupling force and signal connectivity are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The invention specifies that the upper surface has a first curvature radius and the side surface has a second curvature radius, where the first curvature radius is greater than the second curvature radius. This parameter differentiation optimizes the metal layer deposition process and alignment, improving signal connectivity while managing manufacturing precision requirements through controlled geometric parameters.
3Reliability
If the pad has protruding surfaces, then the contact area with insulating layer is increased, but the device thickness increases
Solution Approach 1:
The pad structure extends in multiple dimensions with protruding upper and side surfaces, creating a three-dimensional configuration that maximizes contact area with the insulating layer. This multi-dimensional approach increases bonding force and reliability while efficiently utilizing space to minimize the overall device thickness.
Data Source
AI summary
The present disclosure relates to a printed circuit board including a first insulating layer, a pad embedded in an upper portion of the first insulating and having an upper surface portion, a side surface portion, and a lower surface portion, where a portion of the upper surface portion and a portion of the side surface portion protrude from the upper surface of the first insulating layer, and a metal layer covering the portion of the upper surface portion, the portion of the side surface portion, and a portion of the lower surface portion of the pad.