The Research Of Design And Application For Three-dimensional Integrated Inductor

Inductors are considered important elements in analog,radio frequency(RF),and microwave circuits such as low-noise amplifiers,power amplifiers,filters,oscillators,impedance matching networks and DC-DC converters.In applications,inductors are required to have high quality factor and self-resonant frequency,limited parasitic coupling,smaller die area,and a layout which can be easy to realize and manufacture.In recent years,the design and manufacturing of three-dimensional(3D)integrated circuit has been greatly developed.As a key technology,Through-Silicon-Via(TSV)is used to realize stacking of three-dimensional multi-layer chips.It can provide high aspect ratio interconnections for multi-layer chips in vertical direction.Using TSVs and Redistribution Layer(RDL)metals to realize threedimensional integrated inductor(3D Inductor)is a new choice.It can occupy smaller die area to achieve higher inductance density by using the vertical direction of the chip.In this article,a 3D integrated inductor with spiral structure is designed based on ThroughSilicon-Via technology.The characteristics and inductance model of the 3D integrated inductor and its application in filters are studied in detail.Including the following points:1.Firstly,the characteristics and main parameters of the 3D integrated inductors based on TSV are introduced.Using the electromagnetic simulation software(ANSYS HFSS),the effects of the process parameters and design parameters on the inductance,quality factor and self-resonant frequency of the integrated inductor are studied and analyzed,which provides guidance for the design and application of the inductor.In addition,through the simulation of traditional planar spiral inductor,double-layer spiral inductor(via-based)and 3D integrated inductor based on TSV,it is concluded that the area of TSV-based inductor is only 27% of planar spiral inductor and 63% of double-layer spiral inductor.2.Based on the concept of partial inductance,an accurate inductance calculation model is proposed for 3D integrated inductors.It can reduce the simulation time and computing resources over finite-element-based 3D full-wave simulation.Compared with the existing inductance model of the 3D inductor,our model takes into account the internal selfinductance and mutual inductance between RDLs with different positions.The accuracy of this model is greatly improved.For the 3D integrated inductor with turns of 1 to 10,the calculation error is less than 3.5%.3.Based on the inductance model,a low-pass filter design method based on 3D inductor is proposed.This method can effectively reduce the design time of low-pass filter based on TSV-based integrated inductors.Using this method,a low-pass filter working at 2.4 GHz is designed.Compared with the traditional filters,the area of our filter is significantly reduced.