一种用以改善硅衬底螺旋电感性能的局域介质增厚新技术

提出了一种用于提高硅基螺旋电感性能的局部介质增厚技术.这种技术通过淀积、光刻和湿法腐蚀工艺,局部增加电感下方的氧化层厚度,以降低衬底损耗和提高电感性能.所采用的结构及工艺简单、成本低廉,与CMOS工艺兼容良好.用这种技术制作的几种不同电感量的方形螺旋电感、品质因数和自谐振频率均显著提高.10,5和2nH的电感,品质因数的峰值分别提高了46.7%,49.7%和68.6%;而自谐振频率的改善更明显,分别达到了92.1%,91.0%及不低于68.1%.     

Flip-Chip-Assembled Air-Suspended Inductors

This paper discusses high-performance planar suspended inductors for hybrid integration with microwave circuits. The inductors are fabricated using a silicon surface micromachining foundry process and assembled using flip-chip bonding. The silicon substrate is removed, leaving a metal inductor suspended 60 mum above the microwave substrate, thus reducing the parasitic capacitance and loss. Various rectangular, octagonal, and circular inductor geometries with one to five windings are designed with inductance values between 0.65 and 16 nH to demonstrate the flexibility of this technique. Measured self-resonant frequencies are between 5 and 34.8 GHz, with quality factors from 45 to 100. Equivalent circuits extracted from measurement for each inductor type show good agreement with measured impedance and full-wave simulations over frequency. The dc current handling limit is 200 mA     

Air Cavity Incorporation to LTCC Spiral Inductor for High Q-factor and SRF

We have devised a new LTCC spiral inductor incorporating an air cavity underneath for high Q-factor and high self-resonant frequency (SRF). The air cavity employed under the spiral reduces the shunt capacitance of the inductor, and results in high Q-factor and SRF of the embedded inductors. The optimized spiral inductor with the embedded air cavity shows a maximum Q of 51 and SRF of 9.1 GHz, while conventional spiral inductor has a maximum Q of 43 and SRF of 8 GHz with effective inductance of 2.7 nH.     

硅基平面螺旋电感的等效电路模型和参数提取

针对螺旋电感传统等效电路模型的不足,提出了一种改进形式的集总参数等效电路模型.该等效电路模型能很好地反映出电感参数随频率变化的实际效应,可适用于从低频到自谐振频率的宽频带范围.同时,应用电磁场全波分析方法对CMOS工艺下平面螺旋电感进行仿真分析.从得到的散射参数中提取电感L、Q值及自谐振频率.基于参数优化和曲线拟合技术,给出了等效电路模型中各个元件值的多变量闭合表达式.这些表达式可方便地用于集成电路的设计和优化,从而提高电路设计的性能和效率.     

Micromachined high-Q inductors in a 0.18-μm copper interconnectlow-k dielectric CMOS process

On-chip spiral micromachined inductors fabricated in a 0.18-μm digital CMOS process with 6-level copper interconnect and low-K dielectric are described. A post-CMOS maskless micromachining process compatible with the CMOS materials and design rules has been developed to create inductors suspended above the substrate with the inter-turn dielectric removed. Such inductors have higher quality factors as substrate losses are eliminated by silicon removal and increased self-resonant frequency due to reduction of inter-turn and substrate parasitic capacitances. Quality factors up to 12 were obtained for a 3.2-nH micromachined inductor at 7.5 GHz. Improvements of up to 180% in maximum quality factor, along with 40%-70% increase in self-resonant frequency were seen over conventional inductors. The effects of micromachining on inductor performance was modeled using a physics-based model with predictive capability. The model was verified by measurements at various stages of the post-CMOS processing. Micromachined inductor quality factor is limited by series resistance up to a predicted metal thickness of between 6-10 μm     

On-chip solenoid inductors with high quality factor for high frequency magnetic integrated circuits

On-chip solenoid inductors for high frequency magnetic integrated circuits are proposed. The eddy current loss was reduced by dividing the inductor into three consecutive inductors connected in series. The inductor has an inductance of 1.1nH and the maximum quality factor (Q/sub max/) of 50.5. The self-resonant frequency and the operating frequency at Q/sub max/ are greater than 17.5GHz and 16.7GHz, respectively.     

双层螺旋RF MEMS电感的模拟与设计

分析了双层螺旋电感的等效电路模型,研究了一种与传统CMOS工艺兼容的MEMS工艺,通过腐蚀电感结构下的硅衬底使电感悬空.利用HFSS软件对一些双层螺旋微电感进行了模拟,模拟结果表明,相比传统单层电感,双层电感可以减少60%的芯片面积,10nH的电感也只需要很小的面积,经过MEMS后处理的双层螺旋电感的最大Q值都超过了20.     

改善硅基螺旋电感品质因数的厚铝膜干法刻蚀

提出了一种用于改善硅基螺旋电感品质因数的厚铝膜干法刻蚀技术;这种技术利用氧化硅和光刻胶双层复合掩模来掩蔽厚铝的干法刻蚀,完全兼容于CMOS工艺;应用于双层铝布线,实现了最大厚度达到6μm的顶层铝,显著地减小了螺旋电感的串联电阻,提高了品质因数;该技术同高阻SOI衬底技术相结合,制造的10nH螺旋电感的最大品质因数达到8.6。     

Micromachined planar spiral inductor in standard GaAs HEMT MMICtechnology

A novel free-standing planar spiral inductor with reduced parasitic capacitances is proposed by suspending individually the strips, through a maskless front-side bulk micromachining compatible with a commercial GaAs HEMT monolithic microwave integrated circuit (MMIC) technology. Suspended structures have been fabricated and characterized at frequencies up to 15 GHz, showing quality factors of up to 16 and self-resonant frequency superior to 16 GHz for a 4.8 nH inductor. Moreover, since the standard IC process as well as the unconcerned electronic circuits are not influenced by micromachining, such devices are directly useful to enhance RF circuits, like matching networks, filters, and low-noise amplifiers     

High-Q factor three-dimensional inductors

In this paper, the great flexibility of three-dimensional (3-D) monolithic-microwave integrated-circuit technology is used to improve the performance of on-chip inductors. A novel topology for high-Q factor spiral inductor that can be implemented in a single or multilevel configuration is proposed. Several inductors were fabricated on either silicon substrate (/spl rho/ = 30 /spl Omega/ /spl middot/ cm) or semi-insulating gallium-arsenide substrate demonstrating, more particularly, for GaAs technology, the interest of the multilevel configuration. A 1.38-nH double-level 3-D inductor formed on an Si substrate exhibits a very high peak Q factor of 52.8 at 13.6 GHz and a self-resonant frequency as high as 24.7 GHz. Our 4.9-nH double-level GaAs 3-D inductor achieves a peak Q factor of 35.9 at 4.7 GHz and a self-resonant frequency of 8 GHz. For each technology, the performance limits of the proposed inductors in terms of quality factor are discussed. Guidelines for the optimum design of 3-D inductors are provided for Si and GaAs technologies.     

砷化镓衬底上螺旋电感的建模和分析

针对砷化镓(GaAs)衬底上螺旋电感提出了一种改进形式的集总参数等效电路模型,该等效电路模型能很好地表征螺旋电感的高频效应.同时,应用电磁场全波分析方法对螺旋电感进行仿真,并分析各参数对电感性能的影响.从得到的散射参数中提取出有效电感、Q值和自谐振频率.基于参数优化方法提取等效电路模型中各元件值,并利用曲线拟合技术给出其相应的闭合表达式.这些表达式可用于射频和微波集成电路的设计,从而提高电路设计的性能和效率.     

High-performance large-inductance embedded inductors in thin array plastic packaging (TAPP) for RF system-in-package applications

We report the first demonstration of high-Q embedded inductors fabricated using a thin-array-plastic-packaging (TAPP) technology. The TAPP technology provides a platform that integrates digital, analog, RF integrated circuits, along with high-performance passive components for system-in-package implementation. Embedded inductors ranging from 14 to 300 nH were fabricated. All the inductors with inductance less than 100 nH exhibit self-resonant frequency above 1 GHz. For a 14-nH inductor, Q factor of 35 was achieved at 1.6 GHz and the self-resonance frequency was measured at 6.15 GHz.     

Micromachined bridge-shaped spiral inductor on anodised aluminium substrate

Noble micromachined integrated spiral inductors on anodised aluminium substrate are presented. The RF characteristics of the fabricated inductors have been measured. A high peak Q-factor of 82.36 at 4.2 GHz has been achieved with inductance of 2.59 nH (at 2 GHz) and a self-resonant frequency of around 10 GHz. This work demonstrates that an integrated passive device on anodised aluminium substrate has a competitive RF performance compared to that of LTCC technology.     

Fabrication and performance of novel RF spiral inductors on silicon

This paper presents and discusses the fabrication and the performance of RF circular spiral inductors on silicon. The substrate materials underneath the inductor coil are removed by wet etching process. In the fabrication process, fine polishing of the photoresist is used to simplify the processes and ensure the seed layer and the pillars contact perfectly, and dry etching technique is used to remove the seed layer. The results show that Q-factor of the novel inductor is greatly improved by removing the silicon underneath the inductor coil. The spiral inductor for line width of 50 μm has a peak Q-factor of 17 at frequency of 1 GHz. The inductance is about 3.2 nH in the frequency range of 0.05-3 GHz and the resonance frequency of the inductors is about 6 GHz. If the strip is widened to 80 μm, the peak Q-factor of the inductor reduces to about 10 and the inductance is 1.5 nH in the same frequency range.     

Scalable modeling and comparison for spiral inductors using enhanced 1-π and 2-π topologies

Two different scalable models developed based on enhanced 1-π and 2-π topologies are presented for onchip spiral inductor modeling.All elements used in the two topologies for accurately predicting the characteristics of spiral inductors at radio frequencies are constructed in geometry-dependent equations for scalable modeling.Then a comparison between the 1-π and 2-π scalable models is made from the following aspects:the complexity of equivalent circuit models and parameter-extraction procedures,scalable rules and the accuracy of scalable models.The two scalable models are further verified by the excellent match between the measured and simulated results on extracted parameters up to self-resonant frequency (SRF) for a set of spiral inductors with different L,R and N,which are fabricated by employing 0.18-μm 1P6M RF CMOS technology.     

用分布电容模型分析和优化差分电感

建立了预测片上等效寄生电容的片上电感分布电容模型.预测和解释了差分电感的自激振荡频率的差异.实测数据显示,与单端驱动模式下的相同对称电感相比,差分驱动模式电感提高最大品质因数127%,具有更大的工作频率范围.设计和验证了低寄生电容的差分电感.     

Analysis and Optimum Design of Differential Inductors Using Distributed Capacitance Model

A distributed capacitance model for monolithic inductors is developed to predict the equivalently parasitical capacitances of the inductor.The ratio of the self-resonant frequency (fSR) of the differential-driven symmetric inductor to the fSR of the single-ended driven inductor is firstly predicted and explained.Compared with a single-ended configuration,experimental data demonstrate that the differential inductor offers a 127% greater maximum quality factor and a broader range of operating frequencies.Two differential inductors with low parasitical capacitance are developed and validated.     

Packaging-compatible high Q microinductors and microfilters forwireless applications

To meet requirements in mobile communication and microwave integrated circuits, miniaturization of the inductive components that many of these systems require is of key importance. At present, active circuitry is used which simulates inductor performance and which has high Q-factor and inductance; however, such circuitry has higher power consumption and higher potential for noise injection than passive inductive components. An alternate approach is to fabricate integrated inductors, in which lithographic techniques are used to pattern an inductor directly on a substrate or a chip. However, integrated inductors can suffer from low Q-factor and high parasitic effects due to substrate proximity. To expand the range of applicability of integrated microinductors at high frequency, their electrical characteristics, especially quality factor, should be improved. In this work, integrated spiral microinductors suspended (approximately 60 μm) above the substrate using surface micromachining techniques to reduce the undesirable effect of substrate proximity on the inductor performance are investigated. The fabricated inductors have inductances ranging from 15-40 nH and Q-factors ranging from 40-50 at frequencies of 0.9-2.5 GHz. Microfilters based on these inductors are also investigated by combining these inductors with integrated polymer filled composite capacitors     

Estimation methods for quality factors of inductors fabricated insilicon integrated circuit process technologies

By examining uses of quality (Q) factors for inductors in silicon integrated circuit design, new methods for estimating quality factors are proposed. These methods extract and factors by numerically adding a capacitor in parallel to measured y₁₁ data of an inductor, and by computing the frequency stability factor and 3-dB bandwidth at the resonant frequency of the resulting network. These parameters are then converted to effective quality factors using relationships for simple parallel RLC circuits. By sweeping the numerically added capacitance value, effective duality factors at varying frequencies are computed. These new techniques, in addition to being more relevant for circuit design, provide physically reasonable estimates all the way up to the self-resonant frequencies of inductors. At moderate to high frequencies, the commonly used Q definition [-Im(y₁₁)/Re(y ₁₁)] can significantly underestimate and can even give unreasonable results. Data obtained using the new methods suggest that quality factors remain high and integrated inductors remain useful all the way up to their self-resonant frequencies, contrary to the behavior obtained using -Im(y₁₁)/Re(y₁₁). These indicate that the commonly used technique can lead to improper use and optimization of integrated inductors     

RF MEMS电感的研究与进展

无线通信的迅速发展,对高性能电感有迫切的需要。本文介绍了目前电感的发展状况,包括表面螺旋电感、垂直平面螺旋电感、悬浮螺旋电感和螺线管电感。对各种电感的性能进行了比较,讨论了电感设计所需考虑的问题及相关因素,对各种电感的加工工艺作了介绍。总结了各种电感的品种因数。