Semiconductor Ground Shield Structure for High-Frequency Inductor Q Factor
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Solution Overview
Problem
Conventional planar inductors in semiconductor devices suffer from low quality factor (Q) due to high substrate loss and eddy current losses, which degrade the performance of integrated circuits, especially at high frequencies, and existing ground shields exacerbate these issues by inducing coupling capacitance and eddy current loss.
Innovation Solution
A semiconductor device with a ground shield structure comprising a substrate, a ground ring, and a ground shield with coaxial conductive wirings and a metal wire passing through them, connected to the ground ring, which reduces coupling capacitance and eddy current loss by effectively shielding the electric field and preventing substrate current generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional ground shield with a pattern is used to reduce substrate loss, then substrate current generation is reduced, but coupling capacitance increases and eddy current loss increases
Solution Approach 1:
The ground shield pattern is divided into multiple discrete ground pads arranged in a specific geometric configuration rather than using a continuous pattern. This segmentation reduces the overall contact area with the substrate, thereby minimizing coupling capacitance and eddy current losses while still providing effective electric field termination for substrate loss reduction.
Solution Approach 2:
The ground shield uses specific geometric arrangements of ground pads with optimized dimensions and spacing to achieve different local functions: some pads are positioned to maximize electric field termination while others are spaced to minimize coupling capacitance. The non-uniform distribution creates local optimization zones that balance substrate loss reduction with quality factor maintenance.
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
The proposed ground shield structure significantly improves the quality factor (Q) of inductors by minimizing substrate losses and eddy current losses, enhancing the performance of semiconductor devices at high frequencies.
Implementation Method 1
the shield (e.g. pattern 20) has a large contact area in the middle, which may induce a large eddy current loss and reduce the quality factor (Q) of the inductor
Implementation Method 2
According to Lenz's law, an alternating magnetic field of the inductor can induce an alternating eddy current on the substrate
Implementation Method 3
The eddy current can dissipate the electric energy, which is converted from magnetic energy, through Joule heating
Implementation Method 4
the pattern may induce a large coupling capacitance at high frequencies
Data Source
AI summary
Semiconductor devices having a ground shield structure and methods for their formation are provided herein. An exemplary semiconductor device can include a substrate, a ground ring, a ground shield, an electronic device, and/or an insulation layer. The ground ring can be disposed over the substrate. The ground shield can be disposed over the substrate and surrounded by the ground ring. The ground shield can include a plurality of coaxial conductive wirings and a metal wire passing through the plurality of coaxial conductive wirings along a radial direction. The metal wire can be connected to the ground ring. The electronic device can be disposed over the ground shield. The insulation layer can be disposed between the ground shield and the electronic device.