Integrated Inductor with Patterned Ground Shield
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Solution Overview
Problem
Integrated inductors at 28 nm and 20 nm scales face issues with decreased quality factors due to thinner oxide layers and thicker redistribution layers, affecting capacitance and overall performance.
Innovation Solution
Incorporating a patterned ground shield and inner/external rails disposed perpendicular to the inductor, forming a rail structure that interferes with and shields the magnetic field, thereby enhancing the quality factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oxide layer is made thinner to reduce capacitance, then the inductor quality factor improves, but the manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent introduces a patterned ground shield as an intermediary structure between the inductor and the substrate. This ground shield, with its specific pattern design, acts as a mediator to control and reduce parasitic capacitance without requiring extreme thinning of the oxide layer, thus avoiding the manufacturing precision issues associated with ultra-thin oxide layers.
2Manufacturing precision
If redistribution layers are made thicker to improve manufacturing robustness, then the manufacturing precision improves, but the capacitance among redistribution layers increases
Solution Approach 1:
The patent segments the ground shield into a patterned structure rather than using a continuous ground plane. This segmentation creates multiple isolated ground regions that reduce the parasitic capacitance between redistribution layers while maintaining effective grounding and shielding functions, allowing thicker redistribution layers without excessive capacitance.
3Area of stationary object
If the inductor size is reduced to achieve smaller form factor, then the area decreases, but the inductor quality factor deteriorates due to increased negative effects
Solution Approach 1:
The patent applies local quality by creating a patterned ground shield with specific regional variations. Different areas of the ground shield have different patterns and configurations optimized for local requirements - some areas provide shielding, others provide capacitance reduction, and others provide both. This localized optimization allows compact inductor design while maintaining high quality factor.
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
Improves the quality factor of integrated inductors by 5%-10% by effectively shielding the electromagnetic field, as demonstrated in experimental data.
Implementation Method 1
Incorporating a patterned ground shield and inner/external rails disposed perpendicular to the inductor, forming a rail structure that interferes with and shields the magnetic field
Data Source
AI summary
An integrated inductor includes a patterned ground shield, an inner rail, and an inductor. The patterned ground shield is disposed in a first direction. The inner rail is coupled to the patterned ground shield. The inner rail is disposed inside the integrated inductor and in a second direction. The first direction is perpendicular to the second direction. The inductor is disposed above the patterned ground shield.