新型抛光后晶片表面金属离子清洗工艺

本文提出了一种新型的利用金刚石膜电极电化学氧化进行抛光后晶片金属离子污染的清洗方法。金刚石膜电极电化学氧化,可以制备氧化性强的过氧焦磷酸盐,过氧焦磷酸盐可以有效的氧化表面有机物,同时过氧焦磷酸盐被还原成的焦磷酸盐具有很强的配合力,它能与铜等金属离子络合。将三块晶片在0.01mol/L的CuSO4溶液中进行金属离子污染后进行清洗对比实验。对比实验有三部分,一是采用金刚石膜电化学氧化制备的过氧焦磷酸盐进行清洗,二是传统的RCA清洗方法,三是去离子水清洗。XPS测试结果表明,过氧焦磷酸盐清洗与RCA清洗方法对金属离子的去除效果均小于ppm级。过氧焦磷酸盐清洗对有机物的清洗效果优于传统的RCA清洗方法。因此金刚石膜电化学氧化清洗方法可以有效去除有机污染以及金属离子污染,实现了一剂多用,减少清洗步骤,达到节能环保的目的。     

非离子型表面活性剂结合金刚石膜电化学氧化的新型抛光后晶片清洗工艺

本文针对抛光后晶片的颗粒和有机污染物提出了一种新型清洗方法,它结合了非离子表面活性剂和掺硼金刚石膜（BDD）阳极电化学氧化的优势。非离子表面活性剂可以在抛光后晶片上形成一层保护膜,使晶片表面颗粒易于去除。颗粒去除对比实验结果通过金相显微镜观察得知,体积比为1%的非离子表面活性剂的颗粒去除效果最佳。然而表面活性剂保护膜本身属于有机物,它最终也需要被去除。金刚石膜阳极电化学氧化（BDD-EO）可以用来去除有机物,因为它可以有效降解有机物。三个有机污染物去除对比实验分别为：一是先用非离子表面活性剂再用BDD-EO,二是单纯用BDD-EO去除有机物,第三种是用传统RCA清洗技术。通过XPS检测结果表明,用BDD-EO清洗的晶片表面的有机残留明显少于传统RCA技术,并且晶片表面的非离子表面活性剂也可以有效去除。     

A new cleaning process combining non-ionic surfactant with diamond film electrochemical oxidation for polished silicon wafers

This paper presents a new cleaning process for particle and organic contaminants on polished silicon wafer surfaces.It combines a non-ionic surfactant with boron-doped diamond(BDD) film anode electrochemical oxidation. The non-ionic surfactant is used to remove particles on the polished wafer's surface,because it can form a protective film on the surface,which makes particles easy to remove.The effects of particle removal comparative experiments were observed by metallographic microscopy,which showed tha...     

BDD电极电化学氧化清洗工艺氧化性研究

为了改进现有的RCA清洗法以及臭氧/过氧化氢湿式清洗技术,利用金刚石膜(BDD)电极的高级电化学氧化技术生成过氧化物氧化有机物,以实现简化清洗设备及节能环保。为研究金刚石膜电极的氧化能力,电解不同浓度的硫酸钾溶液,通过高锰酸钾滴定法进行氧化性的测量,研究原料浓度对生成过氧硫酸盐浓度的影响;通过添加KOH调节pH值,研究pH值对电化学制备过氧化物的影响,用该电化学氧化方法与RCA清洗法进行清洗效果对比。实验结果显示,金刚石膜电化学氧化能力可以通过阳极电解液浓度以及pH值的调整得到控制,清洗效果在Si片表面粗糙度方面明显优于传统的RCA清洗法,而且更加节能环保。     

金刚石膜电化学氧化液的制备及清洗技术研究

提出了一种采用电化学去除硅片表面有机物的新的清洗方法,用金刚石膜电极作为阳极,电化学氧化硫酸铵溶液生成稳定的强氧化溶液,电解液的氧化性通过间接碘量法测量。通过大量实验,优化初始电解液的浓度以及初始温度等因素,得到氧化强度最佳的电化学清洗液。用自制氧化液进行硅片表面有机物的清洗实验,并与传统的RCA清洗方法进行对比。通过XPS分析可知,采用新的电化学氧化溶液清洗后的硅片表面有机物去除效果明显优于对比实验样品。     

金刚石膜电化学清洗硅片表面有机沾污的研究

采用金刚石膜电极的电化学方式在专用水基清洗剂中不断产生强氧化剂过氧焦磷酸根离子(P2O4-8),并将此方式作为金刚石膜电化学清洗工艺步骤的第一步,用于氧化去除硅片表面的有机沾污.通过与RCA清洗进行对比实验,并应用X射线光电子谱和原子力显微镜进行清洗效果的检测,结果表明,本清洗工艺处理后的硅片表面有机碳含量更少,微粗糙度小,明显优于现有的RCA清洗工艺.     

BDD 电化学结合表面活性剂的新型清洗方法

提出了一种新型抛光后的清洗方法,采用掺硼金刚石膜作阳极的电化学方法制备出氧化液,用其去除表面有机污染物,同时配合使用非离子表面活性剂去除表面固体颗粒.用金刚石膜电化学制备出氧化液,克服了单纯电化学氧化生成的强氧化性羟基自由基不稳定和寿命短等缺点,实现氧化能力持久保持.表面活性剂能有效地去除表面颗粒,清洗后Si片上会有残留物,氧化液可以将残留物去除.通过实验对比发现,这种新颖的清洗方法在颗粒和有机物去除上有很好的清洗效果,能够满足微电子工艺的发展需求.     

金刚石膜电化学清洗硅片表面有机沾污的研究

采用金刚石膜电极的电化学方式在专用水基清洗剂中不断产生强氧化剂过氧焦磷酸根离子(P2O4-8),并将此方式作为金刚石膜电化学清洗工艺步骤的第一步,用于氧化去除硅片表面的有机沾污.通过与RCA清洗进行对比实验,并应用X射线光电子谱和原子力显微镜进行清洗效果的检测,结果表明,本清洗工艺处理后的硅片表面有机碳含量更少,微粗糙度小,明显优于现有的RCA清洗工艺.     

LED用GaAs抛光片清洗技术研究

伴随着LED照明产业的迅猛发展,高质量的GaAs抛光片需求量日益增大.研究了一种有效的直径5.08 cm低阻GaAs免洗抛光片的清洗技术,采用异丙醇低温超声去蜡结合兆声温法清洗工艺,使晶片表面达到了低表面颗粒度、极低表面金属离子浓度,并形成了较薄的富As氧化层表面.表面颗粒度通过Tencor6220测试大于0.3 μm的颗粒少于10个,通过TXRF测试表面金属离子个数均控制在9×1010/cm2以内;通过台阶仪测量表面粗糙度为0.8 nm,通过偏振光椭圆率测量仪测得均一的2 nm厚表面氧化层.     

硅片清洗研究进展

综述了清洗液的组成、特点、清洗机理、对硅片表面质量的影响以及清洗技术和理论的发展;着重指出了,改进的RCAI对颗粒度、微粗糙度和金属沾污作用的机理,讨论了它与清洗顺序的关系,极度稀释的RCA2能使金属沾污降至10∧10原子/cm∧2以下,且不易使颗粒重新沉淀;最后介绍了清洗工艺的最新进展。     

Influence of initial wafer cleanliness on metal removal efficiencyin immersion SC-1 cleaning: limitation of immersion-type wet cleaning

When contaminated silicon wafers are immersed in an ultra-pure cleaning solution of an NH₄OH/H₂O₂/H ₂O mixture known as the RCA Standard Clean 1 (SC-1), in which the impurity concentration is negligibly low, the level of wafer-surface metallic contamination after the cleaning treatment depends on the amount of metallic impurities brought into the solution by the to-be-cleaned wafers themselves. Even if the chemicals are disposed of after each wafer cleaning, the surface metallic contamination is still dominated by the amount of impurities brought into the fresh solution by the wafers themselves. In the past, purer chemicals have been sought to improve metal removal efficiency, but after reasonably purer chemicals are obtained the efficiency is not governed by the initial chemical purity but by the initial wafer cleanliness. Because of this, scrubbing of dirty wafers-both the backand front-surfaces-before immersion-type wet cleaning is recommended. However, to meet future stricter wafer cleanliness requirements, new cleaning methods in which fresh chemicals are continuously supplied, such as single-wafer spin cleaning, will have to be employed     

通过添加表面活性剂和螯合剂改进硅片化学清洗工艺的研究

通过在传统RCA清洗法所用的SC-1液中,添加表面活性剂四甲基氢氧化铵(TMAH)和/或螯合剂乙二胺四乙酸(EDTA),实验比较了不同清洗方法对颗粒粘污、金属粘污的去除效率;并测试了其对硅片表面粗糙度的影响。用MOS电容结构的击穿电场强度Weibull分布,评价了不同清洗方法所得氧化层的质量。结果表明,上述改进能够显著提高对颗粒粘污和金属粘污的去除效果,同时能省去RCA的SC-2清洗步骤,具有节省工时、化学试剂消耗量小的优势。     

Effective cleaning process and its influence on surface roughness in anodic bonding for semiconductor device packaging

Wafer cleanliness and surface roughness play a paramount role in an anodic bonding process. Impurities and the roughness on the wafer surface result in unbonded areas which lead to fringes and Newton׳s rings. With an augment in surface roughness, lesser area will be in stroke thus making more pressure and voltage to be applied onto the wafers for better bonding. Eventually it became mandatory to choose the best cleaning process for the bonding technology that can substantially reduce the impurities and surface roughness. In this paper, we investigate the bonding of silicon/oxidized silicon on Pyrex (CORNING 7740) glass with respect to surface roughness and cleanliness of the wafers by performing three renowned cleaning processes such as degreasing, piranha, RCA 1& 2 (SC‐Standard Cleaning 1 and 2) and found that RCA compromises the best between the roughness and cleanliness. Studies were also extended to find out the effects of applied voltage and load on the bonded surface. It was observed for samples cleaned with RCA, an increase of 45% in maximum current and decrease of 75% in total bonding time with the applied load and voltage among all the cleaning techniques used. Three dimensional structures for pressure sensor application were successfully bonded by selecting the appropriate load and cleaning process. Atomic force microscopy analysis was done to investigate the surface roughness on silicon/oxidized silicon and Pyrex glass for different cleaning processes. Scanning electron microscopy and optical imaging were performed on the interface for the surface integrity of the bonded samples.     

An Electrochemical Cleaning Technique for Removal of Surface Contamination before Texturization of Silicon Solar Cells

In order to decrease the consumption of reagents and silicon during removal of surface contamination before silicon texturing in solar cell manufacturing industry, a new low-cost surface treatment approach of electrochemical cleaning technique(ECT) is reported. In this technique, a powerful oxidizing electrolyte was obtained from the electrochemical reaction on Boron-doped Diamond(BDD) electrodes, and applied during removal of surface contaminations on silicon wafer surfaces. The slightly polished monocryst...     

Mimicking Biological Phenol Reaction Cascades to Confer Mechanical Function

Phenol reaction cascades are commonly used in nature to create crosslinked materials that perform mechanical functions. These processes are mimicked by electrochemically initiating a reaction cascade to examine if the mechanical properties of a biopolymer film can be predictably altered. Specifically, thin films (≈ 30–45 μm) of the polysaccharide chitosan are cast onto gold‐coated silicon wafers, the chitosan‐coated wafers are immersed in catechol‐containing solutions, and the phenol is anodically oxidized. The product of this oxidation is highly reactive and undergoes reaction with chitosan chains adjacent to the anode. After reaction, the flexible chitosan film can be peeled from the wafer. Chemical and physical evidence support the conclusion that electrochemically initiated reactions crosslink chitosan. When gold is patterned onto the wafer, the electrochemical crosslinking reactions are spatially localized and impart anisotropic mechanical properties to the chitosan film. Further, deswelling of chitosan films can reversibly transduce environmental stimuli into contractile forces. Films patterned to have spatial variations in crosslinking respond to such environmental stimuli by undergoing reversible changes in shape. These results suggest the potential to enlist electrochemically initiated reaction cascades to engineer chitosan films for actuator functions.     

清洗工艺对锗外延片表面点状缺陷的影响

锗外延片表面的雾、水印及点状缺陷等会影响太阳电池的性能和成品率,其中点状缺陷出现的比例最高。研究了锗抛光片清洗工艺对外延片表面点状缺陷的影响,获得了无点状缺陷、低粗糙度及高表面质量的锗单晶片。采用厚度为175μm p型<100>锗单面抛光片进行清洗试验,研究了SC-1溶液的不同清洗时间、清洗温度和去离子水冲洗温度对锗抛光片外延后点状缺陷的影响,分析了表面SiO_2残留和锗片表面粗糙度对外延片表面点状缺陷的影响。结果表明点状缺陷主要是由于锗单晶抛光片表面沾污没有彻底清洗干净以及清洗过程中产生新的缺陷造成的。采用氢氟酸溶液浸泡、SC-1溶液低温短时间清洗结合低温去离子水冲洗后的锗抛光片进行外延,用其制备的太阳电池光电转换效率由原来的25%提高到31%。     

Megasonic cleaning: A new cleaning and drying system for use in semiconductor processing

A compact system for cleaning wafers in all stages of device manufacture has been developed which uses high frequency (0.8 to 1 MHZ) ultrasonic energy (hence, the term “Megasonic”) and a standard chemical solution which is not heated. The patented process effectively removes particles down to approximately 0.3 ym diameter simultaneously from the front and back surfaces, thin organic films, and many ionic impurities. After a brief water rinse, the wafers are dried in a hot air stream. The total cycle time is approximately 15 minutes, and at least 100 wafers can be cleaned in quartz or plastic carriers at the same time and without the need for loading or unloading. Megasonic cleaning has been applied to silicon wafers, ceramics, and photomasks, and has been used for photo- Paper presented at 20th Annual Electronic Materials Conference, University of California at Santa Barbara, CA, June 30, 1978.     

金刚石膜电化学对LCD上残留有机物清洗的研究

随着微电子技术的发展,对清洗技术的要求也越来越严格。LCD由于低功耗、高画质和轻巧等优势,已作为平板显示领域的主导技术。采用金刚石膜电化学的强氧化物质对液晶盒上的残留有机物进行清洗,通过实验得出较好的清洗的氧化浓度和清洗时间,通过显微镜观察,电化学清洗能够有效去除有机物污染,对比了一般清洗与电化学清洗效果,得出了更适合清洗残留有机物的方法。     

GaAs surface wet cleaning by a novel treatment in revolving ultrasonic atomization solution

A novel process for the wet cleaning of GaAs surface is presented. It is designed for technological simplicity and minimum damage generated within the GaAs surface. It combines GaAs cleaning with three conditions consisting of (1) removal of thermodynamically unstable species and (2) surface oxide layers must be completely removed after thermal cleaning, and (3) a smooth surface must be provided. Revolving ultrasonic atomization technology is adopted in the cleaning process. At first impurity removal is achieved by organic solvents; second NH_4OH : H_2O_2 : H_2O =1:1:10 solution and HCl : H_2O_2 : H_2O = 1:1:20 solution in succession to etch a very thin GaAs layer, the goal of the step is removing metallic contaminants and forming a very thin oxidation layer on the GaAs wafer surface;NH_4OH : H_2O =1:5 solution is used as the removed oxide layers in the end. The effectiveness of the process is demonstrated by the operation of the GaAs wafer. Characterization of the oxide composition was carried out by X-ray photoelectron spectroscopy. Metal-contamination and surface morphology was observed by a total reflection X-ray fluorescence spectroscopy and atomic force microscope. The research results show that the cleaned surface is without contamination or metal contamination. Also, the GaAs substrates surface is very smooth for epitaxial growth using the rotary ultrasonic atomization technology.     

GaAs表面旋转超声雾化清洗新技术

研究了一种新型湿法化学清洗半导体GaAs表面的方法。通过简单设计清洗工艺能使GaAs表面产生最低的损伤。GaAs表面清洗必须满足三个条件：(1)清除热力学不稳定因素和表面粘附的杂质,(2) 除去GaAs表面氧化层,(3)提供一个光滑平整的GaAs表面。本文采用旋转超声雾化方式用有机溶剂除去GaAs表面的杂质,再用NH4OH:H2O2:H2O= 1:1:10和HCl:H2O2:H2O=1:1:20顺次腐蚀非常薄的GaAs层,去除表面的金属污染,并在GaAs表面形成一个非常薄的氧化层表面,最后用NH4OH:H2O= 1:5溶液来清除GaAs表面氧化层。测试GaAs表面的特性,分别用X射线光电光谱仪、X射线全反射荧光光谱仪和原子力显微镜测试了GaAs表面氧化的组分、GaAs表面金属污染和GaAs表面形貌,测试结果表明通过旋转超声雾化技术清洗可提供表面无杂质污染、金属污染和表面非常光滑的GaAs衬底,以供外延生长。