Pyrex7740玻璃深刻蚀研究

研究了以TiW/Au为掩膜,在氢氟酸以及氢氟酸加硝酸溶液中Pyrex7740玻璃的湿法深刻蚀现象。实验发现,在氢氟酸中玻璃的刻蚀速率随溶液温度及浓度的升高而升高,室温下纵/横向侧蚀比最小。在氢氟酸中加入少量硝酸后可以提高其刻蚀速率,当硝酸含量为10%时,刻蚀速率可以提高两倍左右。利用上述结果,实现了用一层TiW/Au掩膜制作多种不同深度的玻璃坑槽结构,为玻璃上不同深度沟道制作提供了一种新的方法。     

InAs/GaSb超晶格红外探测器台面湿法腐蚀研究

研究了不同腐蚀体系对InAs/GaSb超晶格材料台面的刻蚀,并从中选择了由氢氟酸、酒石酸和双氧水构成的酒石酸腐蚀体系。该体系较适合InAs/GaSb超晶格材料的刻蚀,刻蚀速率稳定,下切效应小。进一步研究发现当HF达到一定浓度后不再影响刻蚀速度;在较低的酒石酸和双氧水浓度下,刻蚀速度是由氧化过程控制,且反应速度和双氧水的浓度成正比。腐蚀液配比为酒石酸(3.5g)∶H2O2(4mL)∶HF(1mL)∶H2O(400mL),刻蚀速度约为0.5μm/min。     

硅的横向刻蚀技术研究

研究了SF6等离子体横向刻蚀硅的速率和对SiO2的选择性,主要通过改变SF6气体流量和加入O2,提高硅的横向刻蚀速率和对SiO2选择性。实验发现,加入O2能提高SF6等离子对Si的横向刻蚀速率和Si/SiO2的刻蚀速率比。Si的横向刻蚀速率最高可达0．45μm/min,Si/SiO2的刻蚀比可达50：1。最后提出,在一定刻蚀条件下,可增加SiO2掩膜厚度,或用金属铝作掩膜来加大Si的横向刻蚀量。     

SU-8光刻胶氧刻蚀的研究

采用氧气反应离子刻蚀(RIE)SU-8光刻胶,以获得三维SU-8微结构(如斜面)。实验采用套刻、溅射、湿法腐蚀、电镀等技术实现光刻胶上镍掩膜图形化。分别研究氧气气压、射频(RF)功率、氧气流量对刻蚀速率的影响,并对实验结果进行了理论分析,在此基础上可进一步优化刻蚀工艺以获得更高的刻蚀速率。     

玻璃后盖对有机电致发光器件封装性能的影响

实验采用玻璃湿法腐蚀凹槽制备了用于有机电致发光器件封装的玻璃后盖,并分析了氢氟酸浓度、温度、超声和反应物对玻璃刻蚀厚度和玻璃表面平整度的影响,得到了一种简单制备玻璃盖的工艺方法:在氢氟酸浓度为40%,在超声波清洗器中进行玻璃的腐蚀,腐蚀时间为15min,在腐蚀过程中间隔一定时间冲洗反应物后可以得到厚度为0.177mm,表面平整的玻璃封装盖,符合有机电致发光器件的封装要求。使用此方法制备的封装盖在氮气环境下将有机电致发光器件进行封装,可以减缓器件亮度的衰减。     

商品有机玻璃片微结构的深刻蚀研究

研究应用O2反应离子刻蚀(RIE)直接深刻蚀商用有机玻璃(PMMA)片，以实现微结构的三维微加工，工艺简单，加工成本较低，为微器件的高深宽比加工提出了新方法。试样采用Ni作掩膜，以普通的光刻胶曝光技术和湿法刻蚀法将Ni掩膜图形化。工作气压、刻蚀功率等工艺参数对刻蚀速率影响较大。在刻蚀过程中，掩膜上的金属粒子会被刻蚀气体离子轰击而溅射散落出来，形成微掩膜效应。利用这种RIE技术，在适当的溅射功率及气压下，刻蚀速率较快，且获得了较陡直的微结构图形，刻蚀深度达120μm。     

用于悬浮纳米结构制作的氢氟酸气相刻蚀研究

针对纳米悬浮结构的制作,对不同温度和不同气相条件下的氢氟酸(HF)气相刻蚀进行了研究.利用自制的研究装置,使用HF/水混合气体和HF/乙醇混合气体分别进行了HF对PECVD SiO_2的气相刻蚀实验,同时测量了不同衬底温度下刻蚀速率的变化.研究结果表明,在常温常压下,HF/乙醇混合气体气相刻蚀速率约为7.6 nm/s,而HF/水混合气体气相刻蚀速率约为11.5 nm/s.在衬底温度分别为35,40和50℃时,HF/水混合气体的气相刻蚀速率分别为10.25,7.95和5.18 nm/s.利用HF气相腐蚀进行SiO_2牺牲层释放,得到了悬浮的纳米梁结构,梁与衬底的间距为400 nm.     

Pyrex玻璃凹槽刻蚀及槽底粗糙度研究

介绍了用于电容式微传感器的玻璃基底加工方法.目前玻璃刻蚀掩膜层的制作工艺复杂,实验中采用机械掩膜方法,较简单地腐蚀出玻璃凹槽,没有脱膜或钻蚀现象.同时对凹槽底面粗糙度进行了研究,并提出了改善方法,得到粗糙度为(Ra=1.5 nm)的玻璃底面,有利于制作平整的电极.     

深槽隔离技术中硅的反应离子刻蚀

本文叙述了在反应离子刻蚀（ＲｅａｃｔｉｖｅＩｏｎＥｔｃｈｉｎｇ）系统中采用无碳含氟原子刻蚀气体（ＳＦ＿６，ＮＦ＿３）对硅的深槽刻蚀；分析了真空压力、射频功率、气体组合及其流量和电极温度对刻蚀速率、刻蚀剖面的影响；并根据实验结果，绘出了刻蚀速率与以上物理变量的函数关系曲线；得到刻蚀速率０．５～０．７μｍ／ｍｉｎ，糟宽≤５．０μｍ，深度大于６．０μｍ，横向腐蚀小于１．５μｍ的各向异性刻蚀剖面。本研究技术将应用于超高速ＥＣＬ分频器电路，双极高可靠抗辐射加固稳压器件和ＢｉＣＭＯＳ模拟电路的实际制作中。     

石英音叉微细加工若干问题探讨

采用基于半导体工艺的光刻、化学腐蚀等微细加工方法在石英晶体基片上批量制作石英音叉。化学腐蚀石英音叉时，叉指的一个侧面中央有棱角，腐蚀速率先慢后快有利于棱角的消除，但去掉棱角的主要方法是增加腐蚀时问；实验探索了能够耐受长时问腐蚀液浸泡的Cr／Au掩模的制作方法和工艺，成功地腐蚀出石英音叉样品；选用黑白反相的十字套准标记进行石英音叉图形的双面光刻套准可以减小人为对准误差，腐蚀出的双面音叉图形的套准精度可小于3μm。石英晶体结构的三角对称性和Cr／Au掩模的耐腐蚀性是限制微细加工制作石英音叉达到理想形状的关键。     

Development of a TiW plasma etch process using a mixture experimentand response surface optimization

The characteristics of SF₆/He plasmas used to etch TiW have been studied with statistically designed experiments using a Tegal 804 single wafer system. Two processes were developed using both positive and negative photoresist as the mask material for etching TiW. The goal was to consolidate both processes into one. A two-phase experimental approach was taken to generate the processes. In phase 1 a fractional factorial screening experiment was used to identify key factors, and in phase 2 a mixture experiment was used for process optimization. The fractional factorial experiment was initially used to study the effects of reactor pressure, RF power, SF₆/He gas ratio, overetch time, and hard bake. The results of this initial experiment were used to identify the appropriate levels for the main process parameters. Then, at these parameter levels, a mixture experiment was conducted using the partial pressures of SF₆, He, and the nitrogen ballast as the design variables. Since the total pressure in the system is fixed, these three variables are the components of a mixture, and thus form a constrained design space for the experiment. Quadratic and special cubic response surface models were generated for the following responses: TiW etch rate, photoresist etch-rate, selectivity between the TiW and photoresist, uniformity of all etch rates and selectivities, and critical dimension control for the photoresist and TiW. Contour plots for all responses as a function of the partial pressure of SF₆, He, and nitrogen ballast were generated. The contours from these empirical models were analyzed jointly to optimize the processes     

HF酸处理对石英玻璃355 nm激光损伤影响研究

利用HF酸处理提高石英玻璃355nm激光诱导损伤阈值,通过优化HF溶液浓度以及石英玻璃表面的酸处理时间,石英玻璃的透过率和损伤阈值均有所提高,均随HF酸浓度以及酸处理时间的增加呈现先增加后下降变化。实验结果表明质量分数10%的HF浓度刻蚀60 min后石英玻璃的激光损伤阈值为15.17 J/cm2,相比酸处理前提高了167.5%。对比分析了相同激光能量密度作用下有无HF酸处理石英玻璃表面损伤面积变化,最后给出了HF酸处理提高石英玻璃的激光诱导损伤阈值机制。     

Cr掩模在硅湿法刻蚀中的应用研究

针对硅湿法刻蚀中常见的SiO2、Si3N4掩模的缺点,提出了以Cr薄膜层为刻蚀掩模的新方法,并进行了相应的试验.试验结果表明,Cr掩模湿法刻蚀技术可用于硅半导体器件的制作.此项工艺为硅湿法刻蚀加工提供了一条新的技术途径.     

SiO2牺牲层刻蚀实验的研究与分析

氢氟酸(HF)刻蚀SiO2牺牲层受多种因素影响,其中刻蚀液的温度、组分、浓度、被刻蚀结构的形式及结构内部的残余应力等是最主要的。样品设计了多种测试结构,深入研究这些因素对刻蚀速率及结果的影响,并进行了详细的讨论与分析。通过实验可观察到刻蚀过程中的反应限制阶段与扩散限制阶段,说明经长时间的刻蚀,HF的扩散效应将成为影响刻蚀速率的主导因素。对于实验过程中观察到的"凸"状的刻蚀前端和"晕纹"现象,分析认为结构中的应力梯度及材料间不同的亲水性质是产生这些现象的主要原因。     

Experimental analysis of galvanic corrosion of a thin metal film in a multilayer stack for MEMS application

Experimental analysis of galvanic corrosion of an aluminium (Al)–chromium (Cr)–gold (Au) multilayer stack is presented in this paper. The use of two or more stacks of different metal films is common for realisation of various microelectromechanical system (MEMS) devices. However, patterning of the multilayer metal films by lithographic and etching process is very critical due to galvanic corrosion. In a multilayer metal stack film, the knowledge of etch rate of the individual metal layers is very important for designing the process flow for the fabrication of micro-sensors. In the present study, galvanic corrosion characteristics of Al–Cr binary metal stack and Al–Cr–Au ternary metal stack in different etching solutions have been studied. The intermetallic contact area and the exposed metal area in the electrolyte solution were varied using an innovative process step involving silicon shadow mask technique and lithographic process. It is observed from the experimental results that for an intermetallic contact area to exposed metal area ratio of 2, etch rate of aluminium layer is increased by more than two times in aluminium etchant and 80% in Cr etchant as compared to the etch rate of the aluminium layer without intermetallics effect. The results obtained from this study have been applied for designing the fabrication flow and successful realisation of a MEMS piezoresistive accelerometer.     

采用Ti/TiW/Au栅制作Si衬底上CaAs MESFET与集成电路

本文从制备硅集成电路(SiIc)与砷化镓集成电路(GaAs IC)单片兼容电路的要求出发,提出了Ti/TiW/Au肖特基金属化结构,制备出了性能良好的Ti/TiW/Au栅Si衬底上分子束外延(MBE)的GaAsMESFET与GaAs IC。     

AlN基片的薄膜金属化

讨论了ＡｌＮ基片的薄膜金属化。通过试验,确定了有效的清洗方法及优化溅射参数。实验证明,ＴｉＷ－Ａｕ 是ＡｌＮ的优良金属化体系。ＡｌＮ材料经激光划片后出现导电物质, 经稀盐酸处理可去掉导电物质     

反应离子刻蚀PMMA的各向异性刻蚀研究

研究目的是优化Ni掩膜PMMA RIE的刻蚀参数，在氧刻蚀气体中加入表面钝化性气体CHF3，以较快的刻蚀速率获得垂直的侧壁和最小的掩模钻蚀。采用平行板结构的反应离子刻蚀机刻蚀，研究了刻蚀气压，CHF3/O2比率和刻蚀温度对垂直、侧向刻蚀速率和PMMA微结构形貌的影响。试验表明：当CHF3含量大于50%或O2工作气压较低时，会显著影响RV/RL比，当RV/RL比大于8时，试样呈现出完全各向异性刻蚀。     

TaN wet etch for application in dual-metal-gate integration technology

Wet-etch etchants and the TaN film method for dual-metal-gate integration are investigated. Both HF/HN O_3/H_2O and NH_4OH/H_2O_2 solutions can etch TaN effectively, but poor selectivity to the gate dielectric for the HF/HNO_3/H_2O solution due to HF being included in HF/HNO_3/H_2O, and the fact that TaN is difficult to etch in the NH_4OH/H_2O_2 solution at the first stage due to the thin TaO_xN_y layer on the TaN surface, mean that they are difficult to individually apply to dual-metal-gate integration. A two-step wet etching strategy using the HF/HNO_3/H_2O solution first and the NH_4OH/H_2O_2 solution later can fully remove thin TaN film with a photo-resist mask and has high selectivity to the HfSiON dielectric film underneath. High-k dielectric film surfaces are smooth after wet etching of the TaN metal gate and MOSCAPs show well-behaved C-V and J_g-V_g characteristics, which all prove that the wet etching of TaN has little impact on electrical performance and can be applied to dual-metal-gate integration technology for removing the first TaN metal gate in the PMOS region.