Integrated Inductor With Metal-Filled Deep Trenches
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Solution Overview
Problem
Integrated inductors on silicon substrates suffer from low Q-factor due to substrate loss and inefficient eddy current reduction with traditional polysilicon patterned ground shields.
Innovation Solution
The integration of deep trenches in a semiconductor substrate filled with metal materials, such as copper or aluminum, to form a patterned ground shield that blocks deep eddy currents and increases the Q-factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polysilicon patterned ground shield is formed between the inductor and gate oxide layer, then the Q-factor is improved, but deep eddy current in the semiconductor substrate is not effectively blocked
Solution Approach 1:
The patent transitions from a shallow PGS structure to deep trenches extending into the substrate, adding the depth dimension to effectively block deep eddy currents while maintaining the patterned structure above the inductor
Solution Approach 2:
The patent uses a composite structure combining metal fill material in deep trenches with the existing polysilicon PGS layer, creating a multi-layered shield that addresses both shallow and deep eddy current paths
2Ease of manufacture
If polysilicon is used as PGS material, then the PGS can be formed using standard CMOS processes, but the eddy current reduction efficiency is insufficient
Solution Approach 1:
The patent combines metal fill material with the polysilicon PGS layer, creating a composite structure that leverages the low eddy current properties of metal while maintaining compatibility with standard CMOS fabrication processes
Solution Approach 2:
The patent changes the material parameter of the PGS from pure polysilicon to a composite of metal fill and polysilicon, fundamentally improving the eddy current blocking capability while preserving manufacturability
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 approach effectively blocks deep eddy currents, achieving an optimal blocking effect and increasing the Q-factor of integrated inductors, which can be applied to various IC configurations including 3D ICs and Flip Chips.
Implementation Method 1
the integrated inductor has low Q-factor problem due to substrate loss. Thus, a patterned ground shield (PGS) formed by polysilicon is utilized for reducing eddy current of the integrated inductor
Data Source
AI summary
The present invention provides an integrated inductor and an integrated inductor fabricating method. The integrated inductor comprises: a semiconductor substrate, a plurality of deep trenches, and an inductor. The deep trenches are formed in the semiconductor substrate and arranged in a specific pattern, and the deep trenches are filled with a metal material to form a patterned ground shield (PGS). The inductor is formed above the semiconductor substrate. The integrated inductor fabricating method comprises: forming a semiconductor substrate; forming a plurality of deep trenches in the semiconductor substrate and arranging the deep trenches in a specific pattern; filling the deep trenches with a metal material to form a patterned ground shield (PGS); and forming an inductor above the semiconductor substrate.