纳米压印光刻技术--下一代批量生产的光刻技术

纳米压印光刻技术已被证实是纳米尺寸大面积结构复制的最有前途的下一代技术之一。这种速度快、成本低的方法成为生物化学、μ级流化学、μ-TAS和通信器件制造以及纳米尺寸范围内广泛应用的一种日渐重要的方法,如生物医学、纳米流体学、纳米光学应用、数据存储等领域。由于标准光刻系统的波长限制、巨大的开发工作量、以及高昂的工艺和设备成本,纳米压印光刻技术可能成为主流IC产业中一种真正富有竞争性方法。对细小到亚10nm范围内的极小复制结构,纳米压印技术没有物理极限。从几种纳米压印光刻技术中选择两种前景广阔的方法——热压印光刻(HEL)和紫外压印光刻(UV-NIL)技术给予介绍。两种技术对各种各样的材料以及全部作图的衬底大批量生产提供了快速印制。重点介绍了HEL和UV-NIL两种技术的结果。全片压印尺寸达200mm直径,图形分辨力高,拓展到纳米尺寸范围。     

纳米压印光刻模版制作技术

在下一代光刻技术中,光刻的成本越来越高,这使得工业界开始寻找新的技术。纳米压印作为非光学的下一代光刻技术,具有分辨率高、成本低、产率高等诸多优点,因而可能应用于将来的半导体制造中。同时,纳米压印也可以用于微机电系统(MEMS)和其他纳米结构的图形复制。纳米压印光刻技术主要包括热压印、紫外固化压印和微接触法压印。介绍了在这3种纳米压印光刻技术中,压印模版制作的制作工艺和模版表面的防粘连处理,并且讨论3种压印方法适用的不同领域。     

Fabrication of sub-micron high aspect ratio diamond structures with nanoimprint lithography

Polycrystalline diamond with optical quality has been patterned using nanoimprint lithography. Nanoimprint lithography is a rather new method for fabrication of resist structures with features sizes down to at least 20 nm. The pattern used in this article is a grating with a period of 600 nm and a fill factor of 0.5. Using plasma etching the nanoimprinted grating is etched into a freestanding diamond substrate. We have accomplished the fabrication of 300 nm diamond features with a depth of about 2 μm, which corresponds to an aspect ratio of 7.     

新型含硅丙烯酸酯型纳米压印胶的研究与应用

纳米压印技术因其成本低、产量高的优点广受关注,而开发可适用于纳米压印的压印胶成为该工艺的关键。合成了一种硅含量高的单体三(三甲基硅氧基)甲基丙烯酰氧丙基硅烷(TRIS),制备了一种新型紫外纳米压印用含硅丙烯酸酯型压印胶,用四点弯曲实验机和接触角测试仪表征了压印胶与模板的黏附性能,研究了配方组成对模板黏附性能的影响,优化得到了抗黏附性能优异的配方。压印实验结果表明,该压印胶与模板分离时无粘连。AFM与SEM测试结果表明,压印胶上复制得到了线宽149 nm、周期298 nm、深宽比为1的纳米光栅图形,图形结构完整。     

Fully automated hot embossing processes utilizing high resolution working stamps

Nanoimprint lithography (NIL) is a fast replication technology for structures with sizes ranging from micrometer down to few nanometers range. This paper describes the technology for imprinting of polymer substrates as well as spin-on polymers by using soft working stamp materials. A fully automated hot embossing system, the EVG®750 was built to use this rapid replication processes. By utilizing soft working stamps, we demonstrate the possibility to replicate, in fully automated mode, both high-aspect ratio features in thermoplastic materials as needed for microfluidic lab-on-chip applications as well as high resolution features down to 50 nm in polymer that can be used as templates for pattern transfer in the fabrication of plasmonic substrates for bio-sensing applications.     

纳米光刻对准方法及其原理

对准技术对光刻分辨力的提高有着重要作用。45nm节点以下的光刻技术如纳米压印等,对相应的对准技术提出了更高的要求。对光刻技术发展以来主要用于接近接触式和纳米压印光刻的对准技术做总结分类,为高精度的纳米级光刻对准技术提供理论研究基础和方向。经过分析,从原理上将对准技术分为几何成像对准、波带片对准、干涉光强度对准、外差干涉对准及莫尔条纹等五种对准方法。最后结论得出基于条纹空间相位的对准方法具有最好的抗干扰能力且理论上能达到最高的对准精度,而其他基于光强的对准方法的精度更易受到工艺涂层的影响。因此,基于干涉条纹空间相位对准的方法在纳米级光刻对准中具有很好的理论前景。     

从特征尺寸的缩小看光刻技术的发展

从特征尺寸不断缩小变化的角度阐述了近代光刻技术发展的历程。指出90nm节点的主流光刻技术是193nmArF光刻;193nm浸入式光刻技术作为65nm和45nm节点的首选光刻技术,如果配合二次曝光技术,还可以扩展到32nm节点的应用,但成本会增加;如果特征尺寸缩小到22nm和16nm节点,EUV光刻、无掩模光刻以及纳米压印光刻等将成为未来发展的重要研究方向。在对各种光刻技术的原理、特点以及优缺点等分析对比的基础上,对未来主流光刻技术的发展做了一定的展望。     

紫外纳米压印技术的图形转移层工艺研究

研究了紫外纳米压印技术的图形转移层工艺,通过改变膜厚进行压印对比实验,将转速控制在3000～4000r/min,成功地得到了50nm光栅结构的高保真图形,复型精度可以达到93.75%。同时阐明,纳米压印技术由于具有超高分辨率、低成本、高产量等显著特点,将成为下一代光刻技术(NGL)的主要候选者之一。     

Fabrication of Ge2Sb2Te5 based PRAM device at 60 nm scale by using UV nanoimprint lithography

Phase change memory is one of the most promising non-volatile memory for the next generation memory media due to its simplicity, wide dynamic range, fast switching speed and possibly low power consumption. Low power consuming operation of phase change random access memory (PRAM) can be achieved by confining the switching volume of phase change media into nanometer scale. Nanoimprint lithography is an emerging lithographic technique in which surface protrusions of a mold such as sub-100 nm patterns are transferred into a resin layer easily. In this study, crossbar structures of phase change device array based on Ge₂Sb₂Te₅ were successfully fabricated at 60 nm scale by two consecutive UV nanoimprint lithography and metal lift-off process, which showed on/off resistance ratio up to 3000.     

ArF浸没式光刻在55nm逻辑器件制造中的优势

通过比较干法和浸没光刻技术在超越焦深(DOF)提高方面的一些主要特点,举例说明了采用浸没式光刻技术的许多优势。浸没式光刻技术同干法光刻技术比较起来改善了关键尺寸一致性(CDU)又避开了必需而强硬的分辨率提高技术(RET)。因此利用浸没式光刻技术能够有效地减少光学邻近校正(OPC)的麻烦。就成像技术而言,我们研究了光刻技术对畸变的敏感性和浸没式光刻技术光源光谱带宽对强光相对曝光量对数E95波动性能的优势。去年已经见证了被认为对浸没光刻技术在批量生产中主要难题的套刻精度、缺陷控制和焦平面精度方面有效的改进。如今55nm逻辑器件的生产制造技术要求的挑战已经得到了满足。浸没光刻技术的成就包括抗蚀剂圆片内10nm套刻精度和圆片间20nm的套刻精度,每一圆片上低于10个缺陷以及在整个圆片上40nm以内的焦平面误差。我们形成了一个顶涂层抗蚀剂工艺。总之,浸没光刻技术是55nm节点逻辑器件最有希望的制造生产技术,它可提供与干法ArF光刻技术在CDU控制、套刻性能和焦平面精度方面等效的解决方案,缺陷程度没有增加。NEC电子公司今年采用浸没光刻技术完成了55nm逻辑器件"UX7LS"的开发和试生产并形成这种UX7LS的批量生产光刻技术。     

向50nm拓进的光学光刻技术

非光学下一代光刻技术的缓慢进展和国际半导体技术发展规划 (ITRS)的加速 ,使光学光刻肩负着IC产业的重任 ,进一步向亚波长图形领域进军。为此 ,人们开发了大量的光学光刻扩展技术。其中包括传统的缩短波长和增大数值孔径 ,以及为了扩展最小间距线间图形的分辨力而提高部分相干性。通过这些途径 ,在 1 93nm曝光中实现了 >0 .80的数值孔径和0 .85的部分相干性 ,并将进一步向 1 57nm乃止 1 2 6nm过渡。此间 ,离轴照明 (OAI)、移相掩模(PSM)和光学邻近效应校正 (OPC)等K1因子将作为分辨力提高技术的核心 ,补充到光学光刻技术范畴。此外 ,光学光刻的扩展还将通过像场尺寸缩小和倍率增大的方法使步进扫描光刻机更好地支持并可望进入至少 70nm的技术节点 ,乃至 50nm的下一代光刻。     

纳米压印抗粘性技术研究进展

纳米压印是一种理想的光刻技术,它具有生产率和分辨率高的特点。脱模过程中,粘连限制了图形的精确转移,因此,抗粘连成为纳米压印技术需要解决的关键问题。氟化自组装单分子层是一种被广泛应用的抗粘连涂层,介绍和分析了其在耐热性和降解方面的最新研究进展。介绍了类金刚石碳膜、在光刻胶上喷涂脱模剂和含氟表面活化剂在纳米压印抗粘连研究上的进展,分析了这些方法所存在的问题及纳米压印抗粘连的发展趋势。     

光学和电子束曝光系统之间的匹配与混合光刻技术

介绍如何实现光学和电子束曝光系统之间的匹配和混合光刻的技术，包括：(1）光学曝光系统与电子束曝光系统的匹配技术；(2）投影光刻和JBX-5000LS混合曝光技术；(3）接触式光刻机和JBX-5000LS混合曝光技术；(4）大小束流混合曝光技术或大小光阑混合曝光技术；(5）电子束与光学曝光系统混合光刻对准标记制作技术. 该技术已成功地应用于纳米器件和集成电路的研制工作，实现了20nm线条曝光，研制成功了27nm CMOS器件；进行了50nm单电子器件的演试；并广泛地用于100nm化合物器件和其他微/纳米结构的制造.     

Enhanced resolution for future fabrication

We have developed resolution-enhanced optical lithography processes that have enabled us to fabricate devices with deep sub-100 nm feature sizes. Isolated gate features were resolved down to 40 nm in resist using optimized phase-shift lithography processes. The addition of a small reactive ion etch (RIE) etch bias allowed us to fabricate transistors with gate lengths in the range 9-25 nm. This was achieved using standard 248 nm optical stepper, photoresist, and RIE technology. The capability is valuable for providing robust fabrication processes for advanced device technology studies. Double-exposure phase-shift imaging is also achieving growing industry acceptance with promising new results recently reported by UMC and Intel. These results show that optical lithography with aggressive resolution enhancements will likely be able to meet the needs of the semiconductor industry for the rest of this decade, pushing out the anticipated introduction of next-generation lithography (NGL) technologies further into the future.     

Fabrication of a 3D stamp with the micro- and nano-scale patterns through combined NIL and optical lithography processes

Nanoimprint lithography is in the spotlight of the nano technology field for its ability to produce large area patterning [1], [2], [4]. This kind of lithography is also able to fabricate three-dimensional functional structures all at once. In order to fabricate three-dimensional structures for an entire wafer, simple fabrication of three-dimensional large area stamp that combines micro- and nano-scale patterns is required. This paper proposes, the fabrication process of three-dimensional large area stamp that incorporates both micro- and nano-scale pattern. The three-dimensional stamp, which accounts for areas that range from 70nm to 3um, is fabricated on a Si substrate using nanoimprint lithography and optical lithography.     

Comparison of quartz and silicon as a master mold substrate for patterned media UV-NIL replica process

Nanoimprint lithography (NIL) is a promising candidate technology to fabricate patterned media for the next generation hard disk drives (HDD). The requirement of pattern pitch for the HDD or discrete-track recording (DTR) media will be as small as from 40 to 50 nm by 2011 or 2012. However not only to create such fine pitch but also long e-beam writing time such as 1 week with conventional high resolution resist ZEP520A are critical. This paper addresses the fabrication processes to combine silicon substrate and a new chemically amplified resist (CAR) for the master molds of this NIL. The e-beam writing speed with this new CAR was achieved over 3-times faster while 50 nm fine DTR patterns were demonstrated with rotary stage e-beam writer. Furthermore, the replication with J-FIL from the master mold into quartz working mold was also demonstrated.     

超精细图案光刻技术的研究与发展

根据国内外研究和发展现状，对有望突破100nm超精细图案光刻分辨率的一些关键技术进行了阐述，其中包括曝光技术、掩模技术、光学系统改进和以离轴照明、相位移掩模、多重滤光和图形演算为代表的分辨率增强技术等。     

PREVAIL--下一代电子束投影曝光技术

PREVAIL作为下一代电子束投影曝光技术，采用可变轴浸没透镜，对以硅为支架的碳化硅薄膜进行投影微缩曝光。在1mm^2子场的情况下，运用步进扫描曝光方式，在100nm临界尺寸下具有较高的产量，也EUVL技术一起成为下一代曝光技术的有力竞争者。     

Ultrafast deep UV Lithography with excimer lasers

The use of high-power pulsed excimer lasers for photolithography is described for the first time. Short exposure times, high resolution and absence of speckle are experimentally demonstrated. Using a XeCl laser at 308 nm and a KrF laser at 248 nm, excellent quality images are obtained by contact printing in two positive photoresists. Resolution down to 1000 line-pairs/mm is demonstrated. These images are comparable to state-of-the-art lithography done with conventional lamps; the major difference is that the excimer laser technique is ∼ 2 orders of magnitude faster. Preliminary results on reciprocity behavior in several resists are also presented.     

NIL—a low-cost and high-throughput MEMS fabrication method compatible with IC manufacturing technology

Current MEMS fabrication technology cannot satisfy the simultaneous needs of 3D structure fabrication and compatibility with IC manufacturing technology, which have impeded the development of MEMS industrialization to a certain extent. Nanoimprint lithography (NIL) provides a new MEMS fabrication method that is compatible with IC manufacturing technology and bears high throughput and low cost. This paper presents an in-house prototype NIL tool with a high precision automatic alignment system based on moiré fringe signals. Some printing results of nanostructures or micro-devices using the prototype are presented, and hot embossing lithography, one typical NIL technology is depicted in detail by taking microlens array fabrication as an example. High fidelity and fine uniformity demonstrate NIL will be a new method to fabricate 3D structures of MEMS.