梳齿型深硅刻蚀工艺研究

为实现Faims气体传感器梳齿型离子迁移区的设计,文中采用感应耦合等离子体(ICP)刻蚀技术进行大深宽比梳齿型结构的深硅刻蚀。影响刻蚀的工艺参数主要包括RF功率、腔室压力、气体流量等,通过调节刻蚀气体SF6流量、腔室压力等参数进行试验,分析工艺参数对刻蚀速率、表面形貌和侧壁垂直度的影响,选出最优工艺参数。根据选出的最优工艺参数,刻蚀出了侧壁光滑、垂直度为90°的梳齿型迁移区。     

ECR-CVD制备类金刚石碳膜的正交实验法研究

采用系统的正交实验法对ECR-CVD法沉积类金刚石碳膜(DLC)的优化工艺进行研究,并分析不同工艺参数对DLC膜性能的影响.共选择基片温度、H2流量、微波功率、直流偏压、脉冲偏压以及脉冲偏压占空比6个参数建立起6因素5水平的正交表,分别以薄膜摩擦因数、磨损率、显微硬度、拉曼谱中D峰与G峰的面积比ID/IG作为考察对象进行研究.极差分析表明,对不同的考察因素其优化工艺略有区别.在所选的参数范围内,脉冲偏压对所测量的DLC膜的性能影响最大.     

工艺参数对直流磁控溅射法制备氧化铝薄膜的试验研究北大核心

采用直流磁控溅射法在载玻片和不锈钢基底上制备某设计要求的氧化铝薄膜,首先采用单因素法分别分析溅射功率、氧气流量、工作压强、负偏压及本底真空度等制备参数对薄膜沉积速率的影响;在此基础上设计正交试验,研究优化范围内溅射功率、氧气流量、工作压强对沉积速率的影响,并进行极差与方差分析。结果表明,在一定工艺参数范围内,随着溅射功率的增加,薄膜的沉积速率不断增大;氧气流量增加时薄膜的沉积速率不断下降;随着工作压强的增大,薄膜的沉积速率先增大后减小,在1.0 Pa时达到最大速率;加载的负偏压增加时,薄膜的沉积速率不断降低;本底真空度提高时薄膜的沉积速率不断增大;通过使用XRD衍射仪对制备的薄膜进行物相检测,研究结果表明,常温下不同氧气流量制备的氧化铝薄膜均为非晶态;获取了制备所需薄膜的较优的制备工艺。     

工艺参数对直流磁控溅射法制备氧化铝薄膜的试验研究

采用直流磁控溅射法在载玻片和不锈钢基底上制备某设计要求的氧化铝薄膜,首先采用单因素法分别分析溅射功率、氧气流量、工作压强、负偏压及本底真空度等制备参数对薄膜沉积速率的影响;在此基础上设计正交试验,研究优化范围内溅射功率、氧气流量、工作压强对沉积速率的影响,并进行极差与方差分析。结果表明,在一定工艺参数范围内,随着溅射功率的增加,薄膜的沉积速率不断增大;氧气流量增加时薄膜的沉积速率不断下降;随着工作压强的增大,薄膜的沉积速率先增大后减小,在1.0 Pa时达到最大速率;加载的负偏压增加时,薄膜的沉积速率不断降低;本底真空度提高时薄膜的沉积速率不断增大;通过使用XRD衍射仪对制备的薄膜进行物相检测,研究结果表明,常温下不同氧气流量制备的氧化铝薄膜均为非晶态;获取了制备所需薄膜的较优的制备工艺。     

减小SiO2光波导表面粗糙度的ICP干法刻蚀工艺研究

波导表面粗糙度引起的散射损耗是SiO2光波导传输损耗的主要来源,通过降低表面粗糙度可以获得低损耗SiO2光波导。通过优化ICP干法刻蚀工艺的各参数(如温度、压强、气体流量、感应/偏置功率等)获得了低粗糙度的SiO2光波导,并采用SEM和AFM对刻蚀表面粗糙度进行了定量测试。采用优化刻蚀工艺可将表面粗糙度从35.4nm降低到3.6nm,波导传输损耗约为0.1dB/cm。     

工艺参数对多弧离子镀TiAlN涂层铝含量和硬度的影响

为研究不同工艺参数对多弧离子镀制备TiAlN涂层性能的影响规律,设计了L9(3~4)正交试验表,并通过试验研究了弧电流、衬底负偏压、氮气/氩气流量比以及腔体压强对涂层Al含量和硬度的影响规律,得到了最佳工艺参数优化组合。结果表明:影响Al含量的因素按重要性排序依次是:腔体压强、氮气/氩气流量比、衬底负偏压、弧电流。影响涂层硬度的因素按重要性排序依次是:弧电流、氮气/氩气流量比、腔体压强、衬底负偏压。     

ICPECVD法制备氧化硅薄膜的工艺研究

以SH_4和O_2作为反应气体,利用电感耦合等离子体增强型化学气相淀积(ICPECVD)技术制备了氧化硅薄膜,通过正交试验设计的方法研究了反应室压强、衬底温度和射频功率3个关键工艺参数对氧化硅薄膜淀积速率的影响及其显著性。实验结果表明:反应室压强和射频功率对淀积速率的影响具有高度显著性,各参数对刻蚀速率的影响程度依次为反应室压强射频功率衬底温度,并讨论了所选参数对淀积速率的影响机理。     

新型高温压力传感器的设计与性能测试

针对高温恶劣环境下对压力参数的测试需求,以单晶蓝宝石为原材料,对无线无源蓝宝石高温压力传感器进行了设计、工艺加工及性能测试.以压力膜片敏感原理为主要根据,结合不同的信号传输与提取方式,首先对LC谐振式的无线无源蓝宝石高温压力传感器进行了设计,然后通过蓝宝石刻蚀、蓝宝石减薄、直接键合等3个关键工艺实现了蓝宝石密封压力腔的...     

PCVD－Ti（CN）膜的工艺及应用研究

通过正交试验对ＰＣＶＤ－Ｔｉ（ＣＮ）膜的镀膜工艺参数进行了优化，得到一可制备高硬度、高结合牢度和高沉积速率的Ｔｉ（ＣＮ）膜的工艺参数。试验表明，在用ＰＣＶＤ法沉积Ｔｉ（ＣＮ）膜的过程中，ＣＨ４的流量是一个重要的控制参数。过多的ＣＨ４会给Ｔｉ（Ｃｘ）膜带来不利影响。氩气虽然可以提高Ｔｉ（ＣＮ）膜的沉积速率，但降低了膜－基的结合牢度。其冷挤压模具应用结果表明，用优化工艺镀Ｔｉ（ＣＮ）膜的模具可比镀ＴｉＮ膜的模具提高寿命２～４倍；与未镀膜的模具相比，可提高寿命１０倍以上。     

玻璃微流检测芯片厚胶光刻温度条件的平衡优化

采用正性光刻胶AZ 4620进行玻璃微流检测芯片的厚胶光刻制备,试验了各工艺阶段不同的温度参数条件对光刻胶浮雕面形、光刻胶与玻璃基质的粘附性、光刻胶在刻蚀液中的耐受时间、刻蚀速率和最大刻蚀深度等因素的影响。结果表明,软烘温度直接影响曝光显影工艺质量;后烘温度对显影效果有一定影响;坚膜温度对光刻胶浮雕面形、耐受时间有较大影响;而刻蚀环境温度直接影响着刻蚀速率、刻蚀深度和刻蚀面形效果。经平衡优化后,得出了理想的温度参数选取方案。     

用CHF3/Ar为工作气体刻蚀融石英

报道了用氟利昂CHF₃和氩气Ar作工作气体的反应离子刻蚀融石英的技术。研究了气体流速、腔压和射频等离子体功率对刻蚀速度的影响,并分析了刻蚀工艺对样品表面的污染,同时也考察了刻蚀工艺的均匀性和重复性。为了优化刻蚀工艺,采用Rs1/Discover软件工具设计优化实验。实验中射频等离子体功率范围在120～160W,氩气和氟利昂流速分别在15～35sccm(1cm³/min standard cubic centimeter/minute)和20～50sccm范围,腔压在13～19Pa范围,相应的刻蚀速度为15～25nm/min.     

超声技术在石英光纤腐蚀中的运用

为了获得光滑的腐蚀光纤表面并精确管理光纤的腐蚀直径,采用自行设计的超声腐蚀系统,在质量百分比浓度为12.5％的氢氟酸(HF)溶液中研究了超声功率和腐蚀温度对石英光纤包层、纤芯腐蚀速率以及腐蚀后光纤表面形貌的影响.研究表明:在HF溶液中,超声扰动有利于提高光纤的腐蚀速率,光纤腐蚀速率与腐蚀时间呈非线性关系,腐蚀表面随着腐蚀的进行越来越粗糙.基于研究结果,进一步采用质量百分比浓度为12.5％的HF溶液和25％的NH4OH溶液配制了缓冲氢氟酸(BHF)溶液,探讨了光纤腐蚀速率及表面形貌的变化,结果表明:在V(HF)∶V(NH4OH)=2的BHF溶液中,当超声功率为165 W、腐蚀温度为40℃时,可获得光滑的腐蚀光纤表面和腐蚀速率与腐蚀时间的线性关系.     

HfO2薄膜的离子束刻蚀特性研究

实验研究了HfO₂薄膜特性以及掩模材料AZ1350以Ar为工作气体下的离子束的刻蚀特性.给出了离子能量、离子束流密度和离子束入射角等因素与刻蚀速率的关系曲线,用最小二乘法拟合了上述因素与刻蚀斜率的函数关系方程;分析了光刻胶和基片在刻蚀过程中随刻蚀深度的变化对图形转移精度的影响,用AFM的Tapping模式测量了刻蚀前后HfO₂薄膜表面质量的变化.结果表明刻蚀速率与离子能量的平方根,及速流密度成正比,并随离子束入射角变化而变化;与刻蚀前相比,刻蚀工艺降低了因HfO₂薄膜刻蚀深度的增加引起图形转移精度下降,因此提高刻蚀选择比是获得高分辨率图形的前提.研究结果已应用到了在HfO₂/SiO₂多层膜衍射光栅的制作中.     

Mechanical vibration assisted plasma etching for etch rate and anisotropy improvement

A novel plasma etching principle for etch rate and anisotropy improvement is proposed. A substrate vibration mechanism has been used to increase plasma collision energy and realize a better gas flow in the plasma etching reactor, as well as ultrasonic cleaning effects at the low vacuum. An reactive ion etching (RIE) system with an anode fixed to an ultrasonically vibrating support is used to demonstrate the principle. Two vibration frequencies of 28 and 38 kHz are applied to the substrate by changing vibration units, with vibration amplitudes of 13 and 9.3 μm, respectively. Etching experiments upon silicon substrates are performed by using SF₆ gas with and without vibration. Vibration effects on etch rate and anisotropy are examined by SEM micrographs at cleaved cross-section of the etching holes. At present, the system is confirmed to have a maximum etch rate improvement of 78% from its original without vibration.     

Fabricating nanostructures through a combination of nano-oxidation and wet etching on silicon wafers with different surface conditions

This study investigates the surface conditions of silicon wafers with native oxide layers (NOL) or hydrogen passivated layers (HPL) and how they influence the processes of nano-oxidation and wet etching. We also explore the combination of nano-oxidation and wet etching processes to produce nanostructures. Experimental results reveal that the surface conditions of silicon wafers have a considerable impact on the results of nano-oxidation when combined with wet etching. The height and width of oxides on NOL samples exceeded the dimensions of oxides on HPL samples, and this difference became increasingly evident with an increase in applied bias voltage. The height of oxidized nanolines on the HPL sample increased after wet etching; however, the width of the lines increased only marginally. After wet etching, the height and width of oxides on the NOL were more than two times greater than those on the HPL. Increasing the applied bias voltage during nano-oxidation on NOL samples increased both the height and width of the oxides. After wet etching however, the increase in bias voltage appeared to have little effect on the height of oxidized nanolines, but the width of oxidized lines increased. This study also discovered that the use of higher applied bias voltages on NOL samples followed by wet etching results in nanostructures with a section profile closely resembling a curved surface. The use of this technique enabled researchers to create molds in the shape of a silicon nanolens array and an elegantly shaped nanoscale complex structures mold.     

Improving the etching performance of high-aspect-ratio contacts by wafer temperature control: Uniform temperature design and etching rate enhancement

A novel wafer temperature control system using direct expansion cycles is developed to improve etching performance. This system enables rapid temperature control of a wafer with low power consumption. In a previous report, we confirmed that the etching rate and mask selectivity of high-aspect-ratio contact etching could be increased by around 6% and 14%, respectively, by controlling the temperature of the wafer during the etching process. In this study, an advanced wafer temperature control system that realizes not only rapid response but also uniform wafer cooling is developed, and a new etching process that controls O₂ gas flow rate as well as wafer temperature during etching is evaluated to decrease the etching rate depression of high-aspect-ratio contact etching. As a result, a rate of wafer temperature change of 1 °C/s and uniformity of ±0.7% with a coefficient of performance exceeding 3 is achieved over a wafer with a diameter of 300 mm during the etching process. Furthermore, etching rate depression in C₄F₆/Ar/O₂ plasma is decreased from 14.4% to 7.8% for a sample with a diameter of 100 nm and aspect ratio of 30.     

A transmission electron microscope study of the effects of ion etching on cells.

The effects of ion etching on blood cells have previously been studied by scanning electron microscopy. This present study by transmission electron microscopy was undertaken to evaluate the effects of the etching process on the cells. Critical point dried preparations were made, etched and subsequently processed and embedded in Araldite. Examination of thin sections of erythrocytes revealed disintegration of the plasma membrane; the residual membrane destruction products formed the tips of cones produced by long etching times. The effect of etching varied in erythrocytes in the same preparation. Nucleated cells showed a similar disintegration of the plasma membrane, but membranes of mitochondria, granules, vesicles and vacuoles did not exhibit effects of etching comparable to those of the plasma membranes. After treatment with a number of different fixatives, erythrocytes on carbon-coated copper grids were also etched and examined directly in a high voltage electron microscope at 1 MV. The effects were comparable to those seen in thin sections. To study the etch rates of biological materials, the resonant frequencies of quartz crystals were measured after application of thin films of albumen and cholesterol and again after these had been etched. the ratio of the frequency changes indicated that the etch rate of albumen was approximately 2-5 times that of cholesterol. The results are discussed in the light of theories of the mechanisms involved in ion etching.     

Effective removal of Ga residue from focused ion beam using a plasma cleaner

Samples prepared using the focused ion beam (FIB) inevitably contain the surface damage induced by energetic Ga+ ions. An effective method of removing the surface damage is demonstrated using a plasma cleaner, a device which is widely used to minimize the surface contamination in scanning transmission electron microscopy (STEM). Surface bombardment with low-energy Ar+ ions was induced by biasing the sample immersed in the plasma source, so as to etch off the surface materials. The etch rates of SiO2, measured with a bias voltage of 100-300 V, were found to vary linearly with both the time and bias and were able to be controlled from 1.4 to 9 nm/min. The removal of the Ga residue was confirmed using energy dispersive spectroscopy (EDS) after the plasma processing of the FIB-prepared sample. When the FIB-prepared sample was processed via plasma etching for 10 min with a bias of 150 V, the surface Ga damage was completely removed.     

Reactive ion etching of GaAs with SiCl4: A residual damage and electrical investigation

The residual damage incurred by various SiCl₄ reactive ion etching (RIE) conditions was investigated by transmission electron microscopy (TEM), Raman spectroscopy, ion channeling, and electrical characterization methods. Lattice damage to depths greater than 100 nm was incurred in all of the RIE processing situations. The lowest power density, longest etch time RIE exhibited the lowest defect density, roughest surface morphology, and poorest quality GaAs regrowth. The highest power density, shortest etch time RIE displayed the highest defect density, smoothest surface morphology, and highest quality GaAs regrowth. The electrical measurements, Schottky diode characteristics, degraded with decreasing power density and increasing etch times. Overall, the characterization results suggest that the high power density, shortest etch time sample possesses the most desirable properties for device fabrication requirements.     

Numerical study on the low density gas flows in a plasma etch reactor

The direct simulation Monte Carlo method is employed to predict the etch rate distribution on Al wafer for a chlorine feed gas flow. The etching process of an Al wafer in a plasma etch reactor is examined by simulating molecular collisions of reactant and product. The surface reaction on the Al wafer is simply modelled by one-step reaction: 3Cl₂+2Al → 2AlCl₃. The gas flow inside the reactor is compared for six different nozzle locations. The present numerical results show that the etch rate increases with the mass flow rate of source gas Cl₂. It is also shown that the flow field inside the reactor is significantly affected by the nozzle locations.