横线Mura的分析与改善

横线Mura是一种在TFT-LCD生产过程中产生的不良,对于画面品质有较大的影响。文中对横线Mura发生的原因进行分析,通过对金属膜层的应力测量及分析不良区域金属断面结构,认为横线Mura的发生是由于在栅电极成膜过程中,玻璃基板中心和边缘的Mo金属层的应力差异较大,造成在应力释放后Mo金属层与玻璃基板之间结合不紧密,从而影响到栅电极与源电极间的寄生电容参数发生变化和信号电平发生偏移。提出对栅电极膜层结构进行调整,将栅电极底层Mo金属膜去除可以有效地降低不良的发生比率,并进行了相关验证。     

在CMP过程中新型抑制剂对Cu/Ru电偶腐蚀的影响

研究了一种新型抑制剂(2,2′-[[(甲基-1H-苯并三唑-1-基)甲基]亚氨基]双乙醇,TT-LYK)在高碘酸钾(KIO₄)体系下对Cu/Ru电偶腐蚀的影响。通过电化学实验研究了抑制剂对Cu/Ru电偶腐蚀的抑制情况,使用X射线光电子能谱(XPS)分析了抑制剂在Ru表面的作用机理,使用原子力显微镜(AFM)观测抛光后晶圆的表面形貌。电化学测试结果显示,随着抛光溶液中抑制剂质量分数的升高,Cu和Ru之间的腐蚀电位差逐渐从730 mV降低到37 mV。新型抑制剂TT-LYK在Cu互连Ru阻挡层化学机械平坦化(CMP)中能够抑制Cu/Ru的电偶腐蚀。抑制剂TT-LYK与Ru发生反应,在Ru表面生成一层钝化膜,抑制了Cu和Ru之间的电偶腐蚀。抛光液中添加抑制剂TT-LYK后,抛光后Cu的表面粗糙度由5.94 nm降低到0.39 nm,Ru的表面粗糙度由5.12 nm降低到0.24 nm。     

TFT-LCD制造工艺中金属或金属复合膜层坡度角的研究

在薄膜晶体管液晶显示器(TFT-LCD)面板制程中,Gate层(栅极)电路和SD层(源极)电路根据产品电阻等要求可以使用纯金属膜层,如钼、铜等金属膜层,也可以使用金属复合膜层,如铝钼、铝钕钼、钼铝钼等金属复合膜层。当使用不同金属或金属复合膜层作为Gate、SD电路时,应当对应不同的刻蚀液。但在实际生产时,往往是一种刻蚀液同时对应金属膜层或金属复合膜层。由于钼金属膜层的Etch Rate(刻蚀速率)大于铝钼等金属复合膜层Etch Rate,所以当铝钼等金属复合膜层刻蚀完成后对应坡度角有时会存在异常,如膜层角度较大(80～90°)、顶层金属钼发生尖角或缩进等现象,产生宏观不良及进行后工序时会产生相应的光学不良或导致后层物质残留,影响产品品质。本文针对金属膜层或金属复合膜层坡度角进行影响因素分析,主要受刻蚀工序及曝光工序影响。通过对刻蚀液浓度调整、温度调整、刻蚀方式调整及曝光工序等调整减少金属钼发生尖角、缩进几率,将金属膜层坡度角控制在60°左右及金属复合膜层坡度角控制在50°左右,从而降低不良的发生率,提高产品品质。     

用于空间太阳望远镜的双波段极紫外反射镜

Fe-IX/X(λ=17.1nm)和He-II(λ=30.4nm)是太阳辐射的两条重要谱线,极紫外(EUV)空间太阳望远镜通常选择这两条谱线对日冕进行观测。为了实现在同一块反射镜对上述两条谱线同时具有较高的反射率,设计了多层膜膜系结构。首先根据极紫外波段选材原则选择了Si、B4C和Mo 3种材料,构成B4C/Si和Mo/Si叠加的两种周期结构,优化其周期数、膜层厚度等,计算了反射率曲线,并从理论验证了其可行性;然后利用磁控溅射镀膜机,在Si片上镀制了多层膜;最后用激光等离子体反射率计检测了样片的反射率,结果显示,在波长17.1nm和30.4nm处的反射率分别达到19.9%和20.2%。通过选择不同滤光片,如Mg、Al/Zr滤光片,可以获得17.1nm或30.4nm单一谱线的反射,实现了设计目标。     

松下与瑞萨确立32nm晶体管技术量产应用目标将用于便携产品及数字家电用系统LSl

松下与瑞萨科技日前宣布,在两公司共同推进的32nm系统LSI用半导体工艺技术开发方面,确立了32nm晶体管技术等的量产应用目标。两公司计划将该技术应用于便携产品及数字家电用系统LSI。此次,两公司开发的是具有高介电率（high—k）栅极绝缘膜及金属栅极堆栈结构的晶体管技术以及采用超低介电率（low—k）材料的布线技术。     

残影不良分析及改善对策研究

通过对大量残影不良样品进行分析,找到了残影不良产生的原因,并基于分析结果设计了改善残影的实验。通过分析发现:残影不良产生的原因是彩膜侧像素与黑矩阵之间的段差过大,在摩擦工程时段差过大区域形成了摩擦弱区,摩擦弱区内的液晶分子配向较弱,导致不良产生。为降低残影不良进行实验,结果显示:在彩膜侧加覆盖层可以有效降低残影不良的发生率,但不适用于量产;通过采用高预倾角的配向膜材料,同时控制配向膜工程到摩擦工程的时间,可使残影不良发生率由28.2%降低至0.2%,为企业的稳定高效生产奠定了基础。     

日盲探测宽波段低噪声滤波器件的研制

为满足日盲探测系统的技术要求,研制了一种可以实现紫外日盲区(200~270nm)高透射、近紫外到近红外区(300~1200nm)深截止的光学滤光片。通过分析材料的光学特性,结合光学薄膜理论,优化膜系结构,设计了介质与金属组合的膜系。采用电子束加热蒸发的方法沉积金属膜,通过对沉积速率的实验研究,在保证金属光学性能的前提下,有效降低了膜厚控制误差。采用逆向反演法与膜层敏感度分析,对谐振层工艺参数进行优化,有效降低了谐振层的控制误差。该滤光膜在200~270nm波段的平均透射率达到51.21%,在300~1200nm抑制区的平均透射率为0.90%。     

28nm集成电路铜互连弱碱性阻挡层抛光液性能北大核心

报道了一种用于技术节点为28 nm的集成电路多层铜互连阻挡层化学机械平坦化(CMP)的弱碱性抛光液(pH值为8.5),仅由平均粒径为20 nm的硅溶胶、FA/O多羟多胺螯合剂及非离子表面活性剂组成。实验结果表明,研发的弱碱性阻挡层抛光液对牺牲层SiO2、阻挡层Ta及金属互连线Cu等多种材料具有优异的速率选择性,去除速率一致性大于95%,并在28 nm多层铜布线片阻挡层CMP后具有较高的平坦化性能,分别获得了20 nm以下深度的碟形坑和蚀坑。通过电化学极化曲线测试表明,此弱碱性阻挡层抛光液能有效减少Cu和Ta之间的腐蚀电位差,并避免了铜互连结构Cu和Ta界面处电偶腐蚀的产生,这对提高集成电路芯片可靠性具有重要意义。     

热处理对磁控溅射法制备p-ITO(40 nm)薄膜特性的影响

为改善在实际生产中,p-ITO在膜厚较薄时所表现出的多种不良,如退火后膜质存在花斑不良、膜层易被刻蚀液腐蚀等,进行退火对p-ITO薄膜特性影响的研究。本实验利用磁控溅射法在玻璃基板上制备出40nm厚度的p-ITO膜,并在氮气环境中对膜层进行不同温度和时间的退火处理。分别采用XRD、AFM和SEM对p-ITO的结晶度和微观结构进行表征,并使用四探针(4-point probe,4P)和自动光学测试设备分别测试其方块电阻和光透射率。测试结果表明:pITO结晶温度相对于α-ITO存在严重滞后性;α-ITO(40nm)230℃已结晶充分,而p-ITO在230℃才开始结晶;p-ITO在230～250℃时结晶程度及均一性较差,导致多种特性的不稳定,比如膜质花斑状颜色差异(花斑不良),方块电阻、膜层厚度均一性差,膜层易受腐蚀等;退火温度提高到260～270℃时结晶基本完全,对薄膜的各种特性改善效果显著,如方块电阻降低、光透射率增加、花斑和腐蚀改善等。测试数据还反映出玻璃中部位置相对于边缘位置结晶程度差,可能原因为退火设备实际生产时玻璃中间位置热风阻力较边缘位置大,受热不充分导致。适当提高退火温度和时间,对pITO实际生产中遇到的多种不良有显著改善效果。     

FSI推出适用于32nm的ORION单晶圆清洗系统

FSI国际公司前不久在上海举办的“FSI知识服务系列研讨会”上,宣布推出全新的ORION单晶圆清洗系统。该系统特有的闭室设计可实现对晶圆环境的完全控制和维护,满足32nm和22nm技术的关键步骤上多项清洗需要。其中包括减少在超浅层注入后的光刻胶去除的材料损失,避免在高介电系数金属栅和与包含包覆层金属连接的铜的电偶腐蚀和材料损失。     

Effect of 1,2,4-triazole on galvanic corrosion between cobalt and copper in CMP based alkaline slurry

Cobalt has become a new type of barrier material with its unique advantages since the copper-interconnects in the great-large scale integrated circuits (GLSI) into 10 nm and below technical nodes,but cobalt and copper have severe galvanic corrosion during chemical-mechanical flattening.The effect of 1,2,4-triazole on Co/Cu galvanic corrosion in alkaline slurry and the control of rate selectivity of copper and cobalt were investigated in this work.The results of electrochemical experiments and polishing experiments had indicated that a certain concentration of 1,2,4-triazole could form a layer of insoluble and dense passive film on the surface of cobalt and copper,which reduced the corrosion potential difference between cobalt and copper.Meantime,the removal rate of cobalt and copper could be effectively controlled according to demand during the CMP process.When the study optimized slurry was composed of 0.5 wt％ colloidal silica,0.1％vol.hydrogen peroxide,0.05 wt％ FA/O,345 ppm 1,2,4-triazole,cobalt had higher corrosion potential than copper and the galvanic corrosion could be reduced effectively when the corrosion potential difference between them decreased to 1 mV and the galvanic corrosion current density reached 0.02 nA/cm2.Meanwhile,the removal rate of Co was 62.396 nrn/min,the removal rate of Cu was 47.328 nm/min,so that the removal rate ratio of cobalt and copper was 1.32:1,which was a good amendment to the dishing pits.The contact potential corrosion of Co/Cu was very weak,which could be better for meeting the requirements of the barrier CMP.     

各膜层对光刻胶灰化的影响

研究各膜层对灰化速率的影响,增强对灰化工艺的了解,为四次光刻工艺改善提供参考。采用探针台阶仪测量在相同灰化条件下不同膜层样品的灰化速率和有源层损失量,对结果进行机理分析和讨论。实验结果表明:有源层会降低灰化速率,源/漏金属层可以增大灰化速率,栅极金属层对灰化速率无影响。对于正常膜层结构的阵列基板,源/漏层图形密度越大,灰化速率越小,图形密度每增大1%,灰化速率下降14nm/min。有源层和源/漏金属层对灰化等离子体产生影响,从而影响灰化速率。     

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.     

纳米Mo膜的光学特性及最小连续膜厚研究

利用Lambda-900分光光度计，在波长为310～1250nm范围内测量了离子束溅射沉积不同厚度纳米Mo膜的反射率和透射率。选定波长为310nm，350nm，400nm，500nm，550nm，632nm，800nm，1200nm时对薄膜的反射率、透射率和吸收率随膜厚变化的关系进行了讨论。实验结果显示，纳米Mo膜的光学特性有明显的尺寸效应。提出将薄膜对光波长为550nm时的反射率和透射率随Mo膜厚度变化关系的交点对应的厚度作为特征厚度，该厚度可认为是纳米Mo膜生长从不连续膜进入连续膜的最小连续膜厚。利用原子力显微镜(AFM)观测膜厚在15．76nm时的表面形貌，此时表面形貌已呈现连续膜的特征。     

Origin of Surface Defects in PCB Final Finishes by the Electroless Nickel Immersion Gold Process

We suggest a unique mechanism for surface defect generation causing solder joint or bonding failures in printed circuit boards (PCBs). Surface defects can be defined as corroded holes or spikes of the Ni-P layers on the soldering or wire bonding pads of PCBs. The typical defects are the black pad or pinhole pad defects generated after final finishing by the electroless nickel immersion gold (ENIG) process. Once corroded voids or spikes are plentifully created in nickel/gold interfaces, the bonding strength of solder or wire bonding joints is reduced. Therefore, it is important to characterize the details of these surface defects. In this paper, the defect microstructures and the P content variation with the ENIG processes are investigated. The surface defect selectivity with pad size and pad connectivity is suggested based on the key findings of P content variation. An overall mechanism is proposed based on a mixed mode of concentration cell corrosion and galvanic cell corrosion. Based on these results, more reasonable root causes are suggested.     

基于单次曝光多光谱关联成像系统带通滤波器的研究

多光谱关联成像与传统点到点的成像方式不同,该技术是采用调制、解调的方式获取目标的图像信息。搭建了一套基于固定相位板的单次曝光多光谱关联成像系统,完成了多光谱关联成像系统中薄膜器件的研制。选择BK7玻璃作为基底材料,氧化铌(Nb₂O₅)和二氧化硅(SiO₂)为高、低折射率材料。根据光学薄膜基础理论,结合膜系设计软件进行膜系设计和模拟分析,通过建立膜系优化评价函数,实现了0°~30°入射450~700 nm带通滤光膜的设计,并在OZZSQ900型箱式真空镀膜机上完成了该薄膜的研制。通过优化SiO₂膜沉积速率,改善了薄膜表面缺陷,降低了散射损耗。对膜层的残余蒸镀进行分析,利用最小二乘法建立膜层厚度与残余蒸镀量之间拟合函数,调整监控方式,减小残余蒸镀,提高了制备过程中膜厚控制精度。采用安捷伦Cary5000分光光度计测试,在350~440 nm和710~800 nm波段透过率 T ＜0.5%,450~700 nm范围内,光线入射角0°~30°时平均透过率 T >98%的带通滤波器,满足系统使用要求,该研究具有重要的实际意义和工程价值。     

界面粗糙度对真空紫外光学薄膜光谱性能影响研究

设计了193 nm窄角度和宽角度入射增透膜以及正入射高反膜,其中增透膜s和p偏振光透射率的最大偏差分别为0.17%和0.44%。结合标量散射理论和等效吸收层近似理论,多层膜间的粗糙界面等效为薄的吸收层,基于薄膜本征传输矩阵计算分析了不同界面粗糙度下的光谱性能。研究发现,薄膜光谱性能随着界面均方根粗糙度的增加而急剧退化,高反膜反射带宽也随之降低,达到4 nm时,宽角度入射增透膜和高反膜光谱性能在193 nm处分别退化2.04%和2.09%。界面粗糙度是影响高光谱性能真空紫外光学薄膜制备的重要因素。     

碱性抛光液中表面活性剂对铜钽的电偶腐蚀

在阻挡层化学机械抛光(CMP)过程中,阻挡层材料钽(Ta)易与铜(Cu)发生电偶腐蚀.针对这一问题,通过电化学分析方法研究了碱性抛光液中非离子表面活性剂对铜钽腐蚀电位的影响;通过CMP实验研究了非离子表面活性剂对铜钽去除速率的影响.结果表明,随着非离子表面活性剂体积分数增加至9％,铜钽的腐蚀电位均降低.最终确定最佳非离子表面活性剂的体积分数为6％.此时,在静态条件下,铜钽电极之间的电位差为1 mV;在动态条件下,铜钽电极之间的电位差为40 mV,可极大地减弱铜钽电偶腐蚀.同时,铜钽的去除速率分别为47 nm·min-1和39 nm·min-1,铜钽去除速率选择比满足阻挡层CMP要求.     

Effect of Ni-Coated Carbon Nanotubes on the Corrosion Behavior of Sn-Ag-Cu Solder

In this study, the effect of Ni-coated carbon nanotubes (Ni-CNTs) on the corrosion resistance of 95.8Sn-3.5Ag-0.7Cu (SAC) solder at ambient temperature in 3.5 wt.% NaCl solution was investigated using the potentiodynamic polarization method. The corrosion products were analyzed by field-emission scanning electron microscopy (S4800), energy-dispersive spectroscopy, and x-ray diffraction. The results showed that addition of Ni-CNTs enhanced the corrosion resistance of the SAC solder and that increasing the content of Ni-CNTs made the effect more evident. The mechanism of the corrosion resistance improvement is the formation of a compact corrosion layer of Ni-CNTs that provides an inert physical barrier to the initiation and development of corrosion. Furthermore, in the corrosion microcell produced by the Ni-CNTs dispersed in the SAC solder, the Ni-CNTs act as a third phase (electrode) which contributes to reducing the galvanic corrosion between Sn anode and Ag₃Sn cathode. Hence, the corrosion resistance of the composite solders was improved.