Annular Plating Layer for Overhang Compensation in Component Carrier Through Holes
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Solution Overview
Problem
Component carriers face challenges in maintaining mechanical robustness and electrical reliability, especially with increasing miniaturization and the need for efficient heat dissipation, while also managing the formation of mechanical vias and laser vias with copper filling, which can lead to cracks and voids due to excessive overhangs during the plating process.
Innovation Solution
A component carrier design featuring an electrically insulating layer structure with conductive layers and through holes, where an annular plating layer is formed to reduce the overhang size to less than 20 μm, preventing cracks and enhancing electrical reliability by filling the through holes with a conductive medium, and a method involving electroplating to create a compensation plating layer before forming a bridge structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper filling is performed in through holes with excessive overhang, then electrical connectivity is achieved, but cracks and voids form in the conductive filling
Solution Approach 1:
The patent applies preliminary action by forming an annular plating layer on the sidewalls of the through hole before performing copper filling. This pre-plating step reduces the overhang size and creates a supportive structure that prevents cracks and voids during subsequent copper deposition, thereby ensuring electrical reliability without defect formation
Solution Approach 2:
The patent changes the physical parameter of overhang size by depositing an annular plating layer that reduces the horizontal extension of the overhang to less than 20 μm. This parameter modification transforms the geometry of the through hole structure, enabling defect-free copper filling while maintaining electrical connectivity
2Productivity
If miniaturization of component carriers is pursued, then product functionality and integration density increase, but mechanical robustness and heat dissipation become increasingly difficult to maintain
Solution Approach 1:
The patent employs composite material structure by combining multiple layer types including electrically insulating layer structures, electrically conductive layer structures, and annular plating layers. This composite approach enables simultaneous achievement of miniaturization, mechanical robustness, and electrical reliability in component carriers
Solution Approach 2:
The patent segments the through hole structure into distinct functional layers: insulating layers for electrical isolation, conductive layers for connectivity, and annular plating layers for structural support. This segmentation allows each layer to be optimized independently, enabling miniaturization while maintaining mechanical strength
3Object-affected harmful factors
If overhang size is reduced to less than 20 μm through plating, then crack risk in conductive filling is suppressed, but manufacturing process complexity increases
Solution Approach 1:
The patent introduces an annular plating layer as an intermediary structure between the through hole sidewalls and the copper filling. This intermediate layer serves as a bridge that reduces overhang size and prevents cracks, adding only one additional manufacturing step while dramatically improving reliability
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
The solution effectively suppresses the risk of cracks in the conductive filling, ensuring high electric reliability and reliability of the component carrier, even under harsh conditions, by reducing the overhang size and improving the interconnection density.
Implementation Method 1
forming an annular plating layer by plating to cover the sidewalls and to fill at least part of the overhang
Data Source
AI summary
A component carrier with an electrically insulating layer having a front side and a back side, a first and a second electrically conductive layer covering the front side and the back side of the electrically insulating layer, respectively. A through hole extends through both electrically conductive layers and the electrically insulating layer. An overhang is formed along one of the electrically conductive layers and sidewalls of the electrically insulating layer structure delimiting the through hole. An annular plating layer covers the sidewalls and fills part of the overhang such that a horizontal extension of the overhang after plating is less than 20 μm and/or such that a ratio between a horizontal extension of the overhang after plating and a width of a first window through the first electrically conductive layer and/or a width of a second window through the second electrically conductive layer is smaller than 20%.