Spiral Inductor Grounding Structure for Substrate Loss Reduction
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Solution Overview
Problem
Conventional spiral inductor devices in semiconductor integrated circuits face reduced quality factor (Q value) due to conductor loss, parasitic capacitance, and substrate loss, which affects inductor performance.
Innovation Solution
The design incorporates a spiral conductive trace with multiple turns and a non-continuous spiral conductive trace connected to ground, along with a guard ring, to reduce substrate loss and parasitic capacitance by grounding the non-continuous spiral conductive trace, thereby enhancing the Q value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a metal shielding layer is inserted between the spiral conductive trace and the semiconductor substrate to reduce substrate loss, then substrate loss is reduced, but an additional parasitic capacitor is formed between the metal shielding layer and the semiconductor substrate, increasing parasitic capacitance
Solution Approach 1:
The patent extracts and removes the metal shielding layer that causes parasitic capacitance problems, instead using a simplified grounding structure with conductive traces directly connected to ground terminals, thereby eliminating the harmful parasitic capacitance while maintaining substrate loss reduction benefits
Solution Approach 2:
The patent introduces conductive traces as intermediary elements that provide grounding paths without forming parasitic capacitors. These traces act as mediators between the spiral conductive trace and ground, achieving electromagnetic shielding without the harmful side effects of metal shielding layers
2Loss of energy
If the thickness and width of the spiral conductive trace are increased to reduce conductor loss, then conductor loss is reduced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the grounding function into multiple separate conductive traces distributed around the spiral structure, rather than using a single thick trace. This segmentation achieves effective grounding and loss reduction while maintaining manufacturing simplicity and avoiding excessive trace thickness or width
Solution Approach 2:
The patent extends the grounding solution into the planar dimension by distributing multiple grounding traces around the spiral structure, rather than increasing trace thickness in the vertical dimension. This dimensional approach reduces conductor loss effectively without complicating the manufacturing process
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 effectively reduces substrate loss and enhances the Q value of the inductor device, improving its performance by mitigating electric field-induced energy in the substrate and eliminating noise.
Implementation Method 1
substrate loss produced by the coupling between the spiral conductive trace and the semiconductor substrate
Implementation Method 2
parasitic capacitor between the spiral conductive trace and the semiconductor substrate
Data Source
AI summary
A spiral inductor device is provided. The spiral inductor device includes a first spiral conductive trace with multiple turns and a second spiral conductive trace with multiple turns adjacent thereto, disposed on an insulating layer over a substrate, wherein the outermost turn and the innermost turn of the first spiral conductive trace have a first end and a second end, respectively, the outermost turn and the innermost turn of the second spiral conductive trace have a third end and a fourth end, respectively, and the second and fourth ends are connected to ground. A non-continuous spiral conductive trace with a single turn is disposed on the insulating layer, parallel and adjacent to the outermost turn of the first spiral conductive trace, wherein the non-continuous spiral conductive trace is connected to the ground and at least a portion thereof is disposed between the first and the second spiral conductive traces.