PZT薄膜的深槽反应离子刻蚀研究

研究了锆钛酸铅(PZT)薄膜的深槽反应离子刻蚀(DRIE)技术。首先,对比了3种工艺气氛条件下(SF6/Ar、CF4/Ar和CHF3/Ar)刻蚀PZT的效果。实验结果表明,3种工艺气氛下,刻蚀速率都随功率的增加而增加。相同功率下,SF6/Ar的刻蚀速率最高;而CHF3/Ar刻蚀PZT的图形形貌最好,对光刻胶的选择比也最好。最后得出了优化的工艺条件为采用CHF3/Ar,射频(RF)功率为160 W,气体流量比为3∶4(CHF3∶Ar=30 cm3/min:40 cm3/min)时,PZT薄膜的刻蚀速率为9 nm/min,光刻胶的选择比为7。     

An advanced reactive ion etching process for very high aspect-ratio sub-micron wide trenches in silicon

This paper reports on a practical modification of the two-step time-multiplexed plasma etching recipe (also known as the Bosch process) to achieve high aspect-ratio sub-micron wide trenches in silicon. Mixed argon and oxygen plasma depassivation steps are introduced in between the passivation and etching phases to promote the anisotropic removal of the passivation layer at the base of the trench. Argon does not chemically react with polymers and silicon and removes the passivation layer only by physical sputtering. Therefore, it results in a highly anisotropic polymer etching process. This recipe can be easily integrated on conventional ICP equipment and the scalloping on the trench sidewall can potentially be reduced in size to less than 50 nm. To clean up all the passivation residues, a short oxygen plasma step is also added at the end of the cycle that effectively improves the uniformity of the etching profile over various opening sizes. Excellent anisotropy of the inserted argon depassivation step facilitates narrow trenches down to 130 nm wide and gap aspect-ratios as high as 40:1, extending the application of deep reactive ion etching (DRIE) processes into a new broad regime.     

太赫兹E 面分支波导定向耦合器研究

本文基于微细加工技术中的深反应离子刻蚀（DRIE）技术设计了一款中心频率在0.355THz 的E 面3dB 四分支 矩形波导定向耦合器。利用奇偶模分析方法和级联理论分析方法进行分析,计算出了其在给定耦合度条件下各结构初值。 使用Ansoft HFSS 对四分支波导定向耦合器进行仿真优化,结果表明该耦合器性能优异,在0.35-0.36THz 频段内,隔离 度优于40dB,各端口的回波损耗大于40dB,插入损耗小于0.2dB。本文所设计的分支波导定向耦合器结构简单紧凑、性 能优越,具有广阔的应用前景。     

MEMS微型柔性力-位移传动机构设计

为了提高微机电系统中微执行器的作用距离,设计了一种全硅结构的微型柔性力-位移传动机构,用于放大微执行器的输出位移。建立了传动机构的简化力学模型和有限元模型,并对机构性能的影响因素进行了分析。用深层反应离子刻蚀工艺在硅隔离衬底上成功制备了电热微执行器-微型柔性传动机构样机,并进行测试。结果表明,柔性力-位移传动机构能够有效地放大微执行器的输出位移,实测放大倍数达到18.9,可以极大地扩展微机电系统微执行器的应用范围。     

基于约束矩阵与蚁群算法的CAPP加工工序优化排序

针对复杂零件工艺方案全局优化难题,提出基于约束矩阵与蚁群算法进行工序优化的方法。约束矩阵包括客观约束矩阵与费用约束矩阵,在分析两个矩阵的基础上,将客观约束矩阵与费用约束矩阵统一为一个矩阵,在此矩阵约束下,用蚁群算法进行工序排序优化,从而保证快速地得到正确的优化工艺序列。结果表明,所提方法具有良好的实用效果。     

单晶硅振动环陀螺仪的制作

为了简化电容式振动环陀螺仪的制作方法,进一步提高成品率,提出了一种结合反应离子深刻蚀(DRIE)与阳极键合的陀螺仪制备方法。分析了振动环陀螺的工作原理,指出了传统工艺存在的缺陷;对该制作方法所采用的工艺流程进行了详细设计,分析了不同工艺参数对陀螺仪性能的影响,并依据分析和实验结果改进了工艺流程和参数。最后,采用该方法制作了振动环式微机械陀螺仪并进行了测试。实验结果表明,采用该方法能成功制作电容间隙为3μm、厚度为80μm的振动环式陀螺仪微结构。与传统的制作方法相比,工艺流程大为简化,掩模板数量从7块减少到2块,满足器件性能可靠、工艺简单、成品率高的要求。     

DRIE based technology for 3D silicon barcodes fabrication

Microworld barcoding has become a promising tool for cell biology. Individual and subpopulation cell tracking is of great interest to evaluate cell behaviour. Nowadays, many micrometer and even nanometer size silicon structures can be fabricated using microelectronics techniques. In this work we report for first time the development of 3D barcodes based on silicon substrate. The proposed silicon micromachining technology based on deep reactive ion etching (DRIE) allows to obtain micrometer-sized cylindrical structures with vertical etch profile that defines a bit = 1 and non-vertical etch profile that defines a bit = 0. Although this technology will allow more than 15 bits representation, only 4-8 bits are necessary for cell labelling. The results of this work show that DRIE has become a versatile technique to produce high aspect 3D biocompatible silicon-based barcodes structures for cell studies.     

Pressure distributions of gaseous slip flow in straight and uniform rectangular microchannels

This paper presents analytical derivations of the pressure distribution in straight and uniform rectangular microchannels in the slip flow regime and new experimental data in those channels. The flow is to be steady state, two-dimensional, isothermal, and to have negligible transverse velocities with a first order slip boundary condition. The measured pressure distributions of airflows are compared with newly derived analytical results. There is close agreement between the measurements and calculation by the slip flow formula. The dimensionless location of the maximum deviation from the linear pressure distribution is found analytically and compared with the measurements. This dimensionless location of the maximum deviation increases with the increasing pressure ratios in the slip flow regime. The effect of several parameters such as the channel aspect ratio and the Knudsen number on the locations of maximum deviation from linearity are investigated. The nonlinearity of the pressure distribution is also discussed.     

基于ICP工艺的垂直微小硅镜的加工

利用自感应耦合等离子(ICP)蚀刻机进行硅深层反应离子刻蚀,得到了几微米宽的狭槽,其轮廓通常为正锥形,即蚀刻槽的宽度随着蚀刻深度的增大而减小.然而,对一个宽槽来说,由于等离子区内边界层的变形,其蚀刻宽度会随着蚀刻深度的增加而增加.在许多应用中,硅蚀刻轮廓侧面的垂直状况是一个关键性问题.叙述了分离式垂直镜的加工过程;研究了影响蚀刻轮廓的各种重要参数.经过引入多步制法与优化激励源、基底偏压源及加工压力,减小了等离子区边界层内的变形,改善了轮廓的蚀刻状况.得到的结果为:120μm高垂直微镜垂直度为89.7°,200μm高垂直微镜垂直度为89.3°.     

SOI谐振式微型电场传感器的新型制作工艺研究

This paper presents a new fabrication process for the SOI-based novel miniature electric field sensor. This new process uses polyimide film to release the SiO₂ layer.Compared with the CO₂ critical point release method,it significantly improves the device surface cleanliness and shortens the process flow.The impurity on the base layer is analyzed.The problem of peak and butterfly-type contamination occurring on the base layer of the SOI wafer during the DRIE process is discussed and solved by thickening the photoresist layer and coating with polyimide film twice.This new process could fabricate MEMS sensors and actuators such as SOI-based electric field sensors,gyroscopes,and micro mirrors and can be an alternative fabrication process compared to commercial SOIMUMPS fabrication processes.