Integrated Circuit Inductor Shielding with Ground Metal
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Solution Overview
Problem
Conventional inductors in integrated circuit devices occupy a large area of the silicon substrate, leading to increased fabrication costs and inefficiencies due to crosstalk and eddy current loss effects, necessitating a novel arrangement to reduce these issues.
Innovation Solution
The integration of a capacitor within the integrated circuit device, positioned between the on-chip inductor and substrate, utilizing ground shield metal patterns to shield the inductor and reduce coupling effects, with the capacitor also serving as a de-coupling capacitor for the power net to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional inductors are used in integrated circuit devices, then the inductor functionality is achieved, but the area occupied on the silicon substrate is considerably large
Solution Approach 1:
The patent places the capacitor underneath the inductor structure, nesting one component within the spatial footprint of another. The capacitor is formed in the substrate below the inductor's active region, allowing the inductor to occupy its necessary area while the capacitor utilizes the otherwise wasted substrate space beneath it, thereby reducing the total area required for both components.
Solution Approach 2:
The patent transitions from a planar arrangement where capacitors and inductors occupy separate lateral space to a three-dimensional arrangement where the capacitor is positioned vertically beneath the inductor. This vertical stacking in the z-dimension allows both components to coexist within the same lateral footprint, significantly reducing the overall area consumed on the silicon substrate.
2Reliability
If conventional inductor arrangement is used, then inductor functionality is provided, but crosstalk and eddy current loss effects occur
Solution Approach 1:
The patent introduces a ground reference layer positioned between the capacitor and the inductor. This ground layer acts as an intermediary that shields the inductor from electromagnetic interference and crosstalk generated by the capacitor, while also providing a reference potential that reduces eddy current losses. The ground layer mediates the electromagnetic interaction between the two components, eliminating harmful effects.
Solution Approach 2:
The patent utilizes the electromagnetic field naturally generated by the capacitor and transforms it from a harmful crosstalk source into a beneficial shielding mechanism. By positioning the ground layer between the capacitor and inductor, the electromagnetic coupling is converted into an effective ground reference that reduces eddy current losses and provides noise shielding, turning the previously harmful electromagnetic interaction into a protective mechanism.
3Area of stationary object
If capacitor is integrated under the inductor, then area is reduced, but additional fabrication steps or cost increase may occur
Solution Approach 1:
The patent designs the capacitor structure to serve multiple functions simultaneously: it provides capacitance functionality, acts as a ground reference layer for noise shielding, and serves as an eddy current loss reduction mechanism. By making the capacitor multi-functional, the patent eliminates the need for separate ground reference structures, thereby avoiding additional fabrication steps and maintaining manufacturing simplicity while achieving area reduction.
Solution Approach 2:
The patent merges the capacitor structure with the ground reference layer, combining two previously separate components into a single integrated structure. The capacitor's bottom plate is formed as the ground reference layer, eliminating the need for separate ground structures and reducing the number of fabrication steps. This merging allows the capacitor to simultaneously provide capacitance and electromagnetic shielding functions without increasing manufacturing complexity.
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 arrangement reduces the area occupied by the inductor, minimizes crosstalk and eddy current losses, and integrates the capacitor without increasing fabrication costs or adding steps, allowing for efficient operation of the integrated circuit device.
Implementation Method 1
utilizing ground shield metal patterns to shield the inductor and reduce coupling effects
Implementation Method 2
the capacitor also serving as a de-coupling capacitor for the power net to minimize interference
Implementation Method 3
Spiral inductors are widely used in the designs of radio-frequency (RF)/high speed integrated circuit devices
Data Source
AI summary
The invention provides an integrated circuit device. The integrated circuit device includes a substrate. A first capacitor is disposed on the substrate. A first metal pattern is coupled to a first electrode of the first capacitor. A second metal pattern is coupled to a first electrode of the second capacitor. A third metal pattern is disposed over the first and second metal patterns. The third metal pattern covers the first capacitor, the first metal pattern and the second metal pattern. The third metal pattern is electrically grounding. An inductor is disposed over the third metal pattern.