Patterned Ground Shield for Integrated Inductor Quality Factor
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Solution Overview
Problem
The manufacturing of integrated inductors at 28 nm and 20 nm dimensions leads to high capacitance and coupling issues among redistribution layers, affecting the quality factor of inductors, which existing technologies have not adequately addressed.
Innovation Solution
A patterned ground shield with specific connection members and portions is introduced, where non-adjacent portions are connected by first and second connection members, and adjacent portions are connected by a third connection member, enhancing the quality factor of integrated inductors by preventing current flow on the substrate and reducing coupling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If integrated inductors are manufactured at 28 nm and 20 nm dimensions, then manufacturing precision is improved, but capacitance increases and quality factor deteriorates
Solution Approach 1:
The ground shield is divided into multiple discrete portions (first ground shield portion, second ground shield portion, third ground shield portion, fourth ground shield portion) arranged in a specific pattern around the inductor. This segmentation creates spatial separation that reduces capacitive coupling between adjacent conductive elements, thereby improving the quality factor despite miniaturization.
Solution Approach 2:
Different regions around the inductor are assigned different ground shield configurations. The patterned ground shield portions are strategically positioned at specific locations (connected via connection members to form a non-continuous pattern) to locally optimize the electromagnetic environment, reducing parasitic capacitance in critical areas while maintaining overall shielding effectiveness.
2Manufacturing precision
If oxide layer thickness is reduced for miniaturization, then manufacturing precision is improved, but capacitance increases and quality factor deteriorates
Solution Approach 1:
The patent extracts and removes the continuous ground shield structure that would normally be placed directly beneath the inductor, replacing it with a patterned, non-continuous arrangement of ground shield portions connected by thin connection members. This extraction eliminates the harmful capacitive coupling that would occur with a solid ground plane, while still providing necessary shielding through the distributed pattern.
Solution Approach 2:
The connection members act as intermediaries between the separated ground shield portions. These thin conductive elements provide electrical connectivity between the discrete ground portions while minimizing their own capacitive effect, serving as a compromise structure that balances shielding requirements with capacitance reduction.
3Manufacturing precision
If RDL thickness is increased, then manufacturing precision is improved, but coupling capacitance increases and quality factor deteriorates
Solution Approach 1:
The ground shield is segmented into multiple portions with strategic gaps between them, connected by thin connection members. This segmentation reduces the effective area of conductive surfaces in close proximity to the thick RDLs, thereby reducing the parasitic coupling capacitance between the RDLs and the ground shield, even when RDL thickness is increased for manufacturing precision.
Data Source
AI summary
A patterned ground shield includes a plurality of portions, a first connection member, a second connection member, and a third connection member. Each of the first connection member and the second connection member is coupled to any of two of the portions which are not adjacent to each other. The third connection member is coupled to two of the portions which are adjacent to each other.