Floating Patterned Shield for Miniaturized Inductor Quality Factor
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Solution Overview
Problem
The miniature size of integrated inductors in advanced semiconductor processes, such as 28 nm and 20 nm, leads to increased capacitance and negative effects on inductor quality factors, which existing technologies have not adequately addressed.
Innovation Solution
An integrated inductor structure that includes a capacitor, a guard ring, and a patterned shield, where the patterned shield is coupled to the guard ring through the capacitor, forming a floating shield, and an inductor is disposed above them, effectively filtering out direct and low-frequency signals to improve the inductor quality factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the integrated inductor is miniaturized to 28 nm and 20 nm processes, then the device size is reduced and integration density is improved, but the oxide layer becomes thinner causing higher capacitance and the quality factor deteriorates
Solution Approach 1:
The patent divides the shielding structure into multiple segments: a patterned shield layer with specific geometric patterns and a guard ring structure. This segmentation allows each component to address specific interference mechanisms independently, reducing overall capacitance while maintaining shielding effectiveness for the miniaturized inductor
Solution Approach 2:
The patent introduces an intermediate patterned shield layer between the inductor and substrate, coupled through capacitive structures. This intermediary structure acts as a mediator that blocks eddy current paths while managing capacitance, thereby protecting the miniaturized inductor from substrate effects without directly contacting it
2Strength
If redistribution layers (RDLs) are made thicker to support miniaturization, then the structural integrity is improved, but the capacitance among redistribution layers increases and quality factor deteriorates
Solution Approach 1:
The patent applies different structural qualities to different regions: thicker RDLs are used only where structural support is needed, while in the inductor region, the patterned shield and guard ring create localized low-capacitance pathways. This local differentiation maintains structural integrity without uniformly increasing capacitance across the entire device
3Object-affected harmful factors
If a traditional grounded shield is used, then the shielding effectiveness is improved, but eddy currents are generated and quality factor deteriorates
Solution Approach 1:
Instead of using a traditional grounded shield that creates eddy currents, the patent inverts the approach by using a patterned shield with capacitive coupling that does not provide a continuous ground path. This inverted shielding mechanism blocks external interference while preventing eddy current formation, as the shield is not directly grounded
Solution Approach 2:
The patent changes the electrical parameters of the shield structure by introducing capacitive coupling instead of direct grounding. This parameter change transforms the shield from a low-impedance grounded structure to a high-impedance capacitive structure, which blocks eddy currents while maintaining shielding effectiveness through the capacitive barrier
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 configuration enhances the inductor quality factor and efficiency by preventing eddy currents and filtering out unwanted signals, thereby improving the performance of the integrated inductor structure.
Implementation Method 1
a patterned shield coupled to the guard ring through a capacitor, such that the patterned shield is floating
Implementation Method 2
The patterned shield and the capacitor form a filtering circuit for filtering out direct signals and low frequency signals
Data Source
AI summary
An integrated inductor structure includes a capacitor, a guard ring, a patterned shield, and an inductor. The guard ring is coupled to the capacitor. The patterned shield is coupled to the guard ring through the capacitor, such that the patterned shield is floating. The inductor is disposed above the guard ring and the patterned shield.