Electroplated Rolled-Up Inductors With Lower Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional planar spiral inductors have a large footprint, leading to significant parasitic coupling capacitance and ohmic loss, which limits their quality (Q) factor and resonance frequency, while rolled-up inductors with thin conductive pattern layers suffer from high DC and RF resistance.
Innovation Solution
An electroplating method is employed to fill the gaps and/or cores of rolled-up passive components with a functional material, increasing the thickness of the conductive pattern layer without significantly increasing the device's diameter, thereby enhancing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a thin conductive pattern layer is used in rolled-up inductors, then the device footprint is reduced, but the DC resistance and RF resistance increase due to surface and grain boundary resistance and skin effect
Solution Approach 1:
The patent applies nesting by depositing additional conductive material layers inside the rolled-up structure, specifically filling the core region and gaps between turns. This internal reinforcement increases the effective conductive cross-section without increasing the external diameter, thereby reducing resistance while maintaining compact footprint.
Solution Approach 2:
The patent transitions from a two-dimensional thin film approach to a three-dimensional filled structure by depositing material into the core and gaps. This dimensional expansion within the existing footprint increases the effective conductor volume and cross-sectional area, reducing resistance without increasing device area.
2Reliability
If the thickness of the conductive pattern layer is increased, then the DC resistance and RF resistance decrease, but the diameter of the rolled-up device increases significantly
Solution Approach 1:
The patent uses nesting to place additional conductive material within the existing rolled-up structure's core and inter-turn gaps. This internal filling approach increases the effective conductor thickness and cross-section without increasing the external diameter, as the material is nested within the existing geometric envelope.
Solution Approach 2:
The patent applies local quality enhancement by selectively increasing conductive material only in specific regions (core and gaps) rather than uniformly thickening the entire structure. This localized reinforcement improves conductivity where most needed while minimizing overall dimensional increases.
3Ease of manufacture
If conventional planar spiral inductor design is used, then fabrication is simple with standard CMOS processes, but parasitic coupling capacitance and ohmic loss increase due to large footprint
Solution Approach 1:
The patent applies curvature by rolling up the planar spiral structure into a three-dimensional rolled-up configuration. This curvature transforms the flat layout into a compact cylindrical form, reducing the footprint and associated parasitic effects while maintaining compatibility with standard fabrication processes that can create the necessary strained layers for self-rolling.
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 method improves the quality factor (Q) and reduces DC resistance, while maintaining a small footprint, resulting in increased inductance and bandwidth.
Implementation Method 1
A layer comprising a functional material is electroplated onto the conductive pattern layer of each rolled-up passive component, thereby at least partly filling the gaps and/or the core with the functional material
Data Source
AI summary
An electroplating method for enhancing the performance of rolled-up passive components comprises providing an array of rolled-up passive components on a substrate, where each rolled-up passive component comprises a multilayer strip in a rolled configuration including multiple turns spaced apart by gaps. The multilayer strip comprises a conductive pattern layer on a strain-relieved layer, and a core of each rolled-up passive component is defined by a first of the multiple turns. A layer comprising a functional material is electroplated onto the conductive pattern layer of each rolled-up passive component, thereby at least partly filling the gaps and/or the core with the functional material.