Printed Circuit Board Metal Posts with Protective-Layer Plating
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Solution Overview
Problem
The existing methods for forming copper posts on printed circuit boards face issues such as insufficient adhesion, potential damage to insulating materials, quality risks in semiconductor assembly, and significant thickness dispersions due to narrow plating areas, leading to increased costs and process complexity.
Innovation Solution
A method involving processing a via portion in an insulating layer with a protective layer, forming a gap portion, and performing a plating process to fill the via and gap before peeling the protective layer, resulting in metal posts with no plating deviations and improved flatness and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If copper posts are selectively plated on outermost layer, then pitch reduction is achieved, but plating area is narrow resulting in significant thickness dispersions
Solution Approach 1:
The patent applies preliminary action by forming a protective layer on the insulating layer before the plating process. This protective layer extends the plating area beyond the narrow copper post locations, allowing uniform plating across a larger surface area. The protective layer is then removed after plating, leaving precisely formed copper posts with consistent thickness, thus resolving the thickness dispersion issue while maintaining pitch reduction capability
2Manufacturing precision
If grinding is performed after over-plating, then thickness uniformity is improved, but grinding deviations occur and additional costs increase
Solution Approach 1:
The protective layer is formed in advance with the precise thickness and pattern required for the final copper posts. During plating, the protective layer maintains uniform thickness across the plating area, ensuring consistent copper deposition. This preliminary structuring eliminates the need for subsequent grinding operations, avoiding grinding deviations and reducing process complexity while achieving excellent thickness uniformity
Solution Approach 2:
The protective layer serves as an intermediary element during the plating process. It acts as a template that controls the plating area and thickness, allowing uniform copper deposition without requiring post-processing grinding. This intermediary structure simplifies the overall process by replacing the complex grinding operation with a controlled plating process on the protective layer
3Ease of manufacture
If seed layer is formed on solder resist surface, then copper post formation is enabled, but adhesion is insufficient requiring additional roughness formation process
Solution Approach 1:
The protective layer acts as an intermediary between the insulating layer and the copper post formation process. It provides a controlled surface that enhances adhesion between the seed layer and the underlying structure, eliminating the need for additional roughness formation processes. The protective layer's surface properties enable reliable seed layer adhesion while maintaining ease of manufacture for copper post formation
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 process enables the formation of metal posts with consistent thickness and improved reliability, reducing costs and simplifying the manufacturing process while minimizing plating deviations.
Implementation Method 1
performing a plating process to fill the via portion and the gap portion
Data Source
AI summary
A printed circuit board and a method of manufacturing the printed circuit board are provided, the printed circuit board including: a metal post; and an insulating layer covering at least a portion of the metal post, wherein, based on a virtual line on substantially the same level as an uppermost surface of the insulating layer, the metal post includes a first conductive portion disposed below the virtual line, a second conductive portion disposed above the virtual line, and a third conductive portion, at least a portion of the third conductive portion protruding from a side surface of the first conductive portion below the virtual line.