Circuit Board Pad Structure for Thin-Board Delamination Resistance
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Solution Overview
Problem
High-performance semiconductor boards with multiple components mounted on a single board are prone to bending defects, leading to reliability issues such as adhesion deterioration between the pad and the insulating layer, and potential delamination defects.
Innovation Solution
A circuit board design featuring an insulating layer with buried wiring and via layers, and a pad with a protruding portion and an embedded portion, where the protruding portion has varying widths and surface roughness to enhance adhesion, and the embedded portion is in contact with the insulating layer to reduce delamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the board is made thinner to accommodate high-performance semiconductors and multiple components, then the board thickness is reduced, but bending defects occur leading to adhesion deterioration between the pad and insulating layer
Solution Approach 1:
The pad structure incorporates a protruding portion with a curved surface that protrudes from the insulating layer. This curvature design allows the pad to accommodate bending stresses in thin boards without compromising adhesion, as the curved geometry distributes mechanical stress more effectively than a flat pad structure.
Solution Approach 2:
The pad transitions from a conventional two-dimensional flat structure to a three-dimensional structure with a protruding portion. This dimensional change provides additional mechanical interlocking capability with the insulating layer, enhancing adhesion while accommodating the reduced board thickness.
2Ease of manufacture
If conventional flat pad structures are used, then manufacturing is simpler, but cracks occur in the pad and delamination defects arise
Solution Approach 1:
The protruding portion of the pad features a curved surface that protrudes from the insulating layer. This curved geometry reduces stress concentration points compared to sharp corners in flat pads, thereby preventing crack formation while maintaining manufacturing feasibility through standard patterning processes.
Solution Approach 2:
The pad structure exhibits local quality variation with a protruding portion that has different geometric properties than the embedded portion. The curved surface of the protruding portion provides enhanced adhesion locally at the interface with the insulating layer, while the overall structure remains compatible with conventional manufacturing processes.
Data Source
AI summary
A circuit board including an insulating layer burying at least one wiring layer and at least one via layer, and having first and second surfaces facing each other in a first direction, and a pad including a protruding portion protruding from the first surface of the insulating layer and an embedded portion embedded in the insulating layer, and electrically connected to the wiring layer. The protruding portion includes a first portion positioned at the outermost part along the first direction and parallel to a second direction parallel to the first surface, and a second portion connected to the embedded portion and adjacent to the first surface, and in the width along the second direction, the width of the first portion is different from the width of the second portion.