CF4等离子处理在低温硅片直接键合中的应用

键合前用CF4等离子体对硅片表面进行处理,经亲水处理后,完成对硅片的预键合.再在N2保护下进行40h 300℃退火,获得硅片的低温直接键合.硅片键合强度达到了体硅的强度.实验表明,CF4对硅片的处理不仅可以激活表面,而且可以对硅片表面进行有效的抛光,大大加强了预键合的效果.     

单片集成MEMS中的阳极键合工艺

分析了阳极键合工艺的原理及其工艺条件对CMOS电路的影响，并通过理论分析和实验研究了单片集成MEMS中的两种阳极键合方法：对于玻璃在硅片上方的键合方式，通过在电路部分上方玻璃上腐蚀一定深度的腔及用氮化硅层保护电路可以在很大程度上减轻阳极键合工艺的影响；而玻璃在硅片下方的键合方式，硅片上的电路几乎不受阳极键合工艺的影响，两种方法各有优缺点。     

直接键合硅片的亲水处理

硅片直接键合技术的关键是硅片表面的亲水处理。本文研究了亲水处理的微观过程，处理溶液的选择条件及处理的方法。指出只要具有氧化剂的硅片清洗液都可以做亲水处理液。     

硅/硅直接键合的界面应力

硅/硅直接键合技术广泛应用于SOI,MEMS和电力电子器件等领域,键合应力对键合的成功和器件的性能产生很大的影响。键合过程引入的应力主要是室温下两硅片面贴合时表面的起伏引起的弹性应力;高温退火阶段由于两个硅片的热膨胀系数不同引起的热应力和由于界面的本征氧化层或与二氧化硅键合时二氧化硅发生粘滞流动引起的粘滞应力。另外,键合界面的气泡、微粒和带图形的硅片键合都会引入附加的应力。     

φ76mm智能剥离SOI材料的制备及其表面缺陷的分析

结合硅片低温键合和中等剂量的氢离子注入,用智能剥离技术成功地制备了φ７６ｍｍ的ＳＯＩ材料,用原子力显微镜（ＡＦＭ）测得表面粗糙度约为７ｎｍ,比普通的抛光硅片约大一个数量级。ＳＯＩ上层硅膜存在表面缺陷,包括未转移区和气泡等,这是由剥离前硅片键合界面存在的空洞引起。通过改进低温键合工艺,提高键合质量,可得到基本无宏观表面缺陷的ＳＯＩ材料。     

硅片直接键合制作SOI结构的工艺研究

硅片直接键合制作ＳＯＩ结构的工艺研究＝［刊，俄］１９９４，２３（６）．－４６～５４本文研究了硅片热压键合前化学处理原始硅表面对低温下表面半粘附键合质量和ＳＯＩ结构质量的影响。采用二次离子质谱方法分析硅片直接键合形成的ＳＯＩ结构中的杂质分布剖面表明，在...     

硅片键合过程中的接触面积

给出了估计硅片在键合过程中实际接触面积的理论模型.模型描述了硅片表面的凸起分布及其弹性形变对接触面积的影响.对于满足键合条件的硅片表面,荷载压力和表面吸附是促使接触面积增加的主要因素.     

O76mm智能剥离SOI材料的制备及其表面缺陷的分析

结合硅片低温键合和中等剂量的氢离子注入,用智能剥离技术（Ｓｍａｒｔ－ｃｕｔ○Ｒ）成功地制备了７６ｍｍ的ＳＯＩ材料．用原子力显微镜（ＡＦＭ）测得表面粗糙度约为７ｎｍ,比普通的抛光硅片约大一个数量级．ＳＯＩ上层硅膜存在表面缺陷,包括未转移区和气泡等,这是由剥离前硅片键合界面存在的空洞引起．通过改进低温键合工艺,提高键合质量,可得到基本无宏观表面缺陷的ＳＯＩ材料．     

硅片发生室温键合所需的平整度条件

根据薄板弹性力学,推导了室温键合过程中硅片接触表面缝隙封闭的临界条件.硅片的表面起伏幅度、起伏的空间波长、表面张力、材料弹性和硅片厚度都是影响接触表面缝隙封闭的重要因素,越薄的硅片越容易室温键合.     

硅片发生室温键合所需的平整度条件

根据薄板弹性力学 ,推导了室温键合过程中硅片接触表面缝隙封闭的临界条件 .硅片的表面起伏幅度、起伏的空间波长、表面张力、材料弹性和硅片厚度都是影响接触表面缝隙封闭的重要因素 .越薄的硅片越容易室温键合     

Adhesion of NCF to oxidized Si wafers after oxygen plasma treatment

The effect of oxygen plasma treatment on the adhesion between nonconductive film (NCF) and oxidized Si was investigated. Oxidized Si wafers were treated with oxygen plasma for 5 min and then rinsed in de-ionized water (DIW). The water contact angle was measured by means of the sessile drop technique and the surface roughness was measured by means of atomic force microscopy. The adhesion of the NCF to the oxidized Si wafer was evaluated by means of a single-lap shear test after bonding at 150°C for 5 s. Oxygen plasma treatment decreased the water contact angle. The roughness of the oxidized Si wafer decreased when oxygen plasma treatment was applied alone, but was increased when both oxygen plasma treatment and DIW rinse were applied. Similarly, the shear strength decreased when oxygen plasma treatment was applied alone, but the adhesion of NCF increased when both oxygen plasma treatment and DIW rinse were applied. The increased surface roughness of the oxidized Si wafer played an important role in increasing the adhesion between the NCF and the oxidized Si wafer. The shear strength further increased after post-heat treatment at 170°C for 1 hr or at 280°C for 15 s. Low shear strength observed before post-heat treatment was ascribed to incomplete NCF curing. Differences observed in the adhesion strength between two types of NCF were attributed to differences in their curing degrees and their degrees of surface coverage of the oxidized Si substrates.     

Water management on semiconductor surfaces

The wafer direct bonding technique is very sensitive to water adsorbed on surfaces just before bonding; hence it is a useful way to characterize the impact of the trapped water and subsequently the wafer drying efficiency. We have focused this work on the water behavior at the bonding interface depending on the nature of the surface but also depending on the thermal treatment. Then we described the drying impact on surfaces after innovative solvent exposure, in a liquid or in a vapor phase, compared with standard isopropyl alcohol drying. We report characterization results from different techniques investigating both native and thermal oxides. We also characterized innovative solvent drying, especially in a vapor phase.     

超短激光制备单晶硅光栅结构的热积累效应和实验研究

针对超短激光辐照单晶硅材料制备光栅结构存在表面裂纹的缺陷,采用双温模型数值模拟出热积累效应,并且实验验证不同加工参数下制备的单晶硅表面光栅结构的表面质量。数值模拟出不同超短激光功率下电子温度和晶格温度的变化规律,通过调节不同的加工参数制备出单晶硅表面光栅结构沟槽,采用超景深三维显微镜对其表面形貌分析。结果表明:当超短激光的输出功率增大时,激光热驰豫时间变大,增大了非平衡状态下激光的烧蚀强度。单晶硅表面的不平整凹坑造成超短激光的反射和散射,从而使得烧蚀后存在凹坑,造成单晶硅表面的损伤溶蚀。当加工速度和加工次数一定时,增大激光的输出功率可以提高超短激光制备光栅结构的加工效率,但过大的激光功率反而造成光栅结构沟槽两侧出现溶蚀凹坑。     

Development of an Asymmetric Hydrophobic/Hydrophilic Ultrathin Graphene Oxide Membrane as Actuator and Conformable Patch for Heart Repair

A conductive engineered cardiac patch (ECP) can reconstruct the biomimetic regenerative microenvironment of an infarcted myocardium. Direct ink writing (DIW) and 3D printing can produce an ECP with precisely controlled microarchitectures. However, developing a printed ECP with high conductivity and flexibility for gapless attachment to conform to epicardial geometry remains a challenge. Herein, an asymmetrical DIW hydrophobic/hydrophilic membrane using heat-processed graphene oxide (GO) ink is developed. The “Masked spin coating” method is also developed that leads to a microscale GO (hydrophilic)/reduced GO (rGO, hydrophobic) physiological sensor, as well as a macroscale moisture-driven GO/rGO actuator. Depositing mussel-inspired polydopamine (PDA) coating on the one side of the DIW rGO , the ultrathin (approximately 500 nm) PDA-rGO (hydrophilic)/rGO (hydrophobic) microlattice (DrGOM) ECP is bestowed with the flexibility and moisture-responsive actuation that allows gapless attachment to the curved surface of the epicardium. Conformable DrGOM exhibits a promising therapeutic effect on rats' infarcted hearts through conductive microenvironment reconstruction and improved neovascularization.     

表面活化处理在激光局部键合中的应用

为了研究低热应力键合工艺,提出了一种将表面活化直接键合与激光局部键合相结合的键合技术。首先采用RCA溶液对键合片进行表面亲水活化处理,并在室温下成功地完成了预键合。然后在不使用任何夹具施加外力辅助的情况下,利用波长1064nm、光斑直径500μm、功率70W的Nd:YAG连续式激光器,实现了激光局部键合,并取得了6.3MPa~6.8MPa的键合强度。结果表明,这种以表面活化预键合代替加压的激光局部键合技术克服了传统激光键合存在的激光对焦困难,以及压力不匀易损害键合片和玻璃盖板等缺点,同时缩短了表面活化直接键合的退火时间,提高了键合效率。     

硅-硅直接键合的亲水处理及界面电特性

研究了基于亲水处理的微观机理分析和不同清洗剂亲水处理的过程及效果，提出了一种独特的三步亲水处理法。这一方法既能顺利完成室温预缝合，又能减少界面上非定形大尺寸ＳｉＯｘ体的生成，避免了界面对电输运的势垒障碍，获得了理想的键合界面。     

无压力辅助硅/玻璃激光局部键合

提出了一种新的无需外压力作用的硅/玻璃激光局部键合方法,通过对晶圆进行表面活化处理,选择合适的激光参数及加工环境,成功地实现了无压力辅助硅/玻璃激光键合.同时研究了该键合工艺参数如激光功率、激光扫描速度、底板材料等的影响.实验表明,激光功率越大,扫描速度越小,键合线的宽度就越大.实验结果显示,该方法能有效减少键合片的残余应力,控制键合线宽,并能得到较好的键合强度.该工艺可为MEMS器件的封装与制造提供简洁、快速、键合区可选择的新型键合方法.     

基于氧等离子体活化的硅硅直接键合工艺研究

基于氧等离子体活化的硅硅直接键合是一种新型的低温直接键合技术。为了优化工艺参数,得到高质量的键合硅片,选用正交试验法,研究了氧等离子体活化时间、活化功率、氧气流量三个重要的工艺参数对键合的影响,并采用键合率评估键合质量。研究结果表明,活化功率对键合率的影响最大,氧气流量次之,活化时间对结果影响最小,据此结论,在上述工艺中需重点关注活化功率和氧气流量的参数选择。     

Phase transformations during the Ag-In plating and bonding of vertical diode elements of multijunction solar cells

The conditions of the bonding of silicon multijunction solar cells with vertical p-n junctions using Ag-In solder are studied. The compositions of electrodeposited indium films on silicon wafers silver plated by screen printing and silver and indium films fabricated by layer-by-layer electrochemical deposition onto the surface of silicon vertical diode cells silver plated in vacuum are studied. Studying the electrochemical-deposition conditions, structure, and surface morphology of the grown layers showed that guaranteed bonding is provided by 8-min heat treatment at 400°C under the pressure of a stack of metallized silicon wafers; however, the ratio of the indium and silver layer thicknesses should not exceed 1: 3. As this condition is satisfied, the solder after wafer bonding has the InAg₃ structure (or InAg₃ with an Ag phase admixture), due to which the junction melting point exceeds 700°C, which guarantees the functioning of such solar cells under concentrated illumination.     

Infrared spectroscopy of bonded silicon wafers

Infrared spectra of multiple frustrated total internal reflection and transmission for silicon wafers obtained by direct bonding in a wide temperature range (200–1100°C) are studied. Properties of the silicon oxide layer buried at the interface are investigated in relation to the annealing temperature. It is shown that the thickness of the SiO₂ layer increases from 4.5 to 6.0 nm as the annealing temperature is increased. An analysis of the optical-phonon frequencies showed that stresses in the SiO₂ relax as the annealing temperature is increased. A variation in the character of chemical bonds at the interface between silicon wafers bonded at a relatively low temperature (20–400°C) is studied in relation to the chemical treatment of the wafers’ surface prior to bonding. Models of the process of low-temperature bonding after various treatments for chemical activation of the surface are suggested.