纳米器件的一种新制造工艺——纳米压印术

纳米压印术可以用于大批量重复性地制备纳米图形结构。此项技术具有操作简单、分辨率高、重复性好、费时少,成本费用极低等优点。本文介绍了较早出现的软刻印术的两种方法———微接触印刷法和毛细管微模制法。详细讲述了纳米压印术(主要指热压雕版压印法)的各步工序———压模制备、压印过程和图形转移,以及用于压印的设备、纳米图案所达到的精确度等,还简述了纳米压印术的另一方法———步进-闪光压印法。最后,通过范例介绍了纳米压印术在制作电子器件、CD存储器和磁存储器、光电器件和光学器件、生物芯片和微流体器件等方面的应用。     

紫外纳米压印OLED衬底微结构的制备技术

在有机发光二极管(OLED)器件衬底上制备可传递三维立体微结构可有效消除波导、增加出光耦合,从而增加器件出光效率。纳米压印技术是制备立体微结构的主要方法之一。采用紫外纳米压印技术在OLED衬底上制备三维立体微结构。首先采用电子束光刻(EBL)技术与干法刻蚀相结合的方法来制备高精度的紫外纳米压印模板;然后对模板进行清洗与抗粘连处理;最后采用紫外纳米压印技术在OLED衬底上成功制备了可传递三维立体微结构。制备结果表明,所形成的微结构具有均匀性好和压印精度高的特点。     

应用传统紫外光刻机进行紫外压印

基于紫外光固化的紫外纳米压印技术可在常温常压条件下实现纳米结构批量复制,具有高分辨率、高效率和低成本的优点。通过对紫外纳米压印原理和工艺的分析,制备了石英玻璃模板,实现了在商用紫外固化聚合物OG154上的紫外纳米压印,转移复制了具有100nm特征的5cm×5cm面积的纳米结构图形。同时,介绍了如何利用传统紫外光刻机的套刻对准系统进行紫外纳米压印和套刻对准的方法。     

气囊气缸式真空紫外纳米压印设备研制

本文介绍了紫外纳米压印技术原理,以及工艺中模板与基片的平行度对压印质量的影响.研制了气囊气缸式真空紫外纳米压印设备,其通过气囊气缸使模板与基片平行,从而可在大面积基片上确保压力均匀.研制了相应的光学系统,着重讨论了如何实现紫外纳米压印以及光学系统的设计和调整.制备了石英玻璃模板,实现了在商用紫外固化聚合物OG154上的紫外纳米压印,转移复制了具有100nm特征的5cm×5cm面积的纳米结构图形.     

纳米器件的一种新制造工艺——纳米压印术(续)

3.3.2图案的保真度、压印面积与图案均匀性Chou等人[15]曾经把聚合物薄膜上压印出的沟槽图案与进而用剥离技术转移得到的线条图案进行比较,以此作为图案保真度的指标。结果是:压印所得宽15nm的沟槽,经过剥离技术转移后成为宽25nm的线条。Dahl-YoungKhang等人[20]用直径100mm的压模在直径100mm的硅片上压印出了分布于不同位置的5个纳米图案,这5个图案与压模上相应图案没有明显的不同,可见在大面积上压印图案的均匀性很好。图8(b)是5个聚合物图案其中一个的SEM照片,图案是一排宽度小于100nm的沟槽,图8(a)是与之相应的压模上图案,可以看出图…     

纳米压印技术进展及应用

半导体加工几十年里一直采用光学光刻技术实现图形转移,最先进的浸润式光学光刻在45 nm节点已经形成产能,然而,由于光学光刻技术固有的限制,已难以满足半导体产业继续沿着摩尔定律快速发展.在下一代图形转移技术中,电子束直写、X射线曝光和纳米压印技术占有重要地位.其中纳米压印技术具有产量高、成本低和工艺简单的优点,是纳米尺寸电子器件的重要制作技术.介绍了传统纳米压印技术以及纳米压印技术的新进展,如热塑纳米压印技术、紫外固化纳米压印技术、微接触纳米压印技术、气压辅助纳米压印技术、激光辅助压印技术、静电辅助纳米压印技术、超声辅助纳米压印技术和滚轴式纳米压印技术等.     

基于旋涂的纳米压印技术研究

尝试使用一种新的工艺——旋涂法来达到图案复制的目的，介绍了旋涂法完成图案复制的实验过程，就印章及其复制品的尺寸作了对比，并分析了实验中观察到的缺陷。得出在精确控制实验条件的前提下，可以通过旋涂方法得到高品质微纳米级图案的结论。     

纳米压印光刻技术

为了避免纳米压印光刻技术与光刻技术混淆，纳米压印光刻技术严谨的专业术语定义是：不使用光线或者辐射使光刻胶感光成形，而是直接在硅衬底或者其他衬底上利用物理学机理构造纳米级别的图形。这种纳米成像技术真正地实现了纳米级别的图形印制。     

纳米压印用压印胶的研究进展

纳米压印需采用压印胶进行图案转移,作为压印技术的关键材料,压印胶的性能直接影响到纳米压印的质量。根据压印技术的工艺特点对压印胶进行了分类,介绍了纳米压印用热压印胶和紫外压印胶的发展研究现状和性能优缺点,分析了目前压印胶存在的主要问题,并指出压印胶的研究主要是提高压印胶的脱模性能、固化速率以及简化工艺,主要列举了含氟硅类压印胶、双表面能压印胶的性能特点,并展望了未来的发展方向。     

一种新型聚合物微透镜阵列的制造技术

提出了一种利用软模压印制备微透镜阵列的技术.采用传统的光刻胶热熔方法制备微透镜阵列母板,利用复制模具的方法在聚二甲基硅氧烷(PDMS)上得到一个和母板表面图形相反的模具,最后通过压印的方法把PDMS模具上的图形转移到涂有紫外固化胶的玻璃基片上,待紫外胶完全固化后可得到和母板一致的微透镜阵列.经过测试微透镜阵列的焦点图像和表面形貌可发现最后制备的微透镜阵列表面形貌均匀、聚焦性能良好、光忖强均匀.     

Structure size dependent recovery of thin polystyrene layers in thermal imprint lithography

Thermal imprints into polymer layers, which are thin compared to the structure height of the stamp provide the advantage that minimum residual layers can be achieved. On the other hand, due to the specific properties of thermoplastic polymers, recovery, i.e. a release of stored imprint energy, may occur after separation of sample and stamp. The intensity of this recovery strongly depends on the imprint temperature. Unfortunately a reduction of recovery by means of increased imprint temperature often generates other problems like unwanted physical self-assembly of the polymer.Another parameter that affects the development of recovery is the structure size of the imprinted patterns. This contribution is about the structure size dependency of the intensity of polymer recovery. By means of lift-off imprints of different structure sizes and types are tested after the imprint at two different temperatures.     

Fingerprint stamp for evaluation of polymer flow time constants in thermal nanoimprint

In order to develop an easy to handle, low-cost procedure to derive imprint-relevant characteristic polymer data from simple imprint experiments, a fingerprint stamp was designed and tested. It contains line and dot structures of different, well-graded sizes in the micron range, where the gaps in between are chosen as to assure independent intrusion of the single patterns into the polymer layer. By imprint of this stamp into a well-characterised polymer, PS 350k, a feasibility test was performed. A pattern size dependent change of the imprint characteristics was observed during the imprint under high-shear into thin layers. This is taken as a hint that polymer characterisation from such experiments is indeed possible. Such data can be adopted to optimise an imprint process for mixed pattern sizes ranging from the micron down to the nanometre scale.     

Optimization and experimentation of nanoimprint lithography based on FIB fabricated stamp

The maskless and resistless focused ion beam (FIB) fabrication approach to make imprint stamp is straightforward and rapid compared to the traditional electron beam method. FIB etched stamp consisting of grooves was employed to nanoimprint polymer mr-I 9020. Taguchi orthogonal experiment with four parameter elements, one at three levels was used to optimize the experiment parameters by the analysis of means and variances. The most significant factor influencing the height of replicated lines is imprint temperature and the optimal combination of the process parameters are the imprint temperature at 160 °C, imprint force at 1200 N, loading force velocity at 0.2 mm/min, and imprint time at 300 s.     

Fabrication of 50 nm patterned nickel stamp with hot embossing and electroforming process

Fabrication of imprint stamp is a key issue of nanoimprint lithography. In this study, we attempt to fabricate the nickel imprint stamp using hot embossing lithography and electroforming processes. As small as 50 nm sized patterns of original silicon master were faithfully transferred to polyvinyl chloride (PVC) film. By electroforming on hot embossed PVC film, nickel stamp, which has the same patterns of original silicon master stamp, was successfully fabricated.     

UV nanoimprint using flexible polymer template and substrate

Nano to micro-sized patterns were formed on a flexible polymer substrate using a flexible UV imprint stamp. A 6 in. diameter flexible UV nanoimprint template was fabricated using PVC hot embossing and DLC coating. Using the UV nanoimprint process with the DLC coated PVC template, nano to micro-sized patterns were clearly formed on the flexible PET substrate without a residual layer, due to the antistiction properties and high mechanical hardness of the DLC coating. By depositing a Cr layer on the imprinted resist pattern and lifting it off, Cr metal patterns were fabricated on the PET substrate.     

Novel Process to Improve Defect Problems for Thermal Nanoimprint Lithography

The reliability of imprint patterns molded by stamps for industrial application of nanoimprint lithography (NIL) is an important issue. Usually, defects can be produced by incomplete filling of negative patterns and the shrinkage phenomenon of polymers in conventional NIL. In this paper, the patterns that undergo a varied temperature or varied pressure period during the thermal NIL process have been investigated, with the goal of resolving the shrinkage and defective filling problems of polymers. This paper also studies the effects on the formation of polymer patterns in several profiles of imprint processes. Consequently, it is observed that more precise patterns are formed by varied temperature (VT-NIL) and varied pressure (VP-NIL). The NIL (VT-NIL and VP-NIL) process has a free space compensation effect on the polymers in stamp cavities. From the results of the experiments, the polymer's filling capability can be improved. VT-NIL is merged with the VP-NIL, resulting in a better filling property. The patterns that have been imprinted in merged NIL are compared with the results of conventional NIL. This study achieves improvement in the reliability of the results of thermal NIL     

Nanoimprint in PDMS on glass with two-level hybrid stamp

In this article we examine the use of two-level hybrid-material stamps and nanoimprint lithography (NIL) of poly(dimethylsiloxane) (PDMS) on glass substrates. A silicon/SU8 stamp manufacturing process has been developed, in order to combine nanometer and micrometer structures, thus avoiding complex deep etching processes. The stamp has been test printed in polymethyl methacrylate (PMMA) to demonstrate functionality. We describe polymer flow problems for imprinting large structures and identify optimized parameters, in accordance with previously published findings. The use of PDMS as imprint polymer was examined. Imprinting works well, however, large recovery after separation shrinks the micrometer channels substantially and renders the nanochannels useless. Glass substrates in combination with silicon stamps were used, evaluated and showed to work well at low temperature.     

A 4-in.-based single-step UV-NIL tool using a low vacuum environment and additive air pressure

Ultraviolet nanoimprint lithography (UV-NIL) is a promising technology for the fabrication of sub-10-nm features. Research has focused on employing a large-area stamp to improve UV-NIL throughput, but a large-area stamp makes it difficult to obtain an acceptable uniform residual layer thickness and/or avoid defects such as air entrapment. This paper presents the development of a single-step UV-NIL tool in which a 4-in. Pyrex stamp is first used to imprint coated resin against a 4-in. Si wafer in a low vacuum environment. Pressurized N₂ is subsequently applied to the wafer bottom to improve the quality of imprint results. This UV-NIL tool was used to successfully imprint a 4-in. stamp with recessed patterns engraved over the entire stamp areas onto a 4-in. Si wafer.     

Fabrication of roll imprint stamp for continuous UV roll imprinting process

Recently, nano imprint lithography has been developed for mass production of nano-scale patterns on large-scale substrates. To achieve high throughput and cost reduction, roll-to-roll imprint lithography has been introduced. The roll-to-roll imprint is the suitable process for large area patterning, especially, flexible substrates for display devices. In this study, roll-to-roll imprint stamp is fabricated using poly-vinyl alcohol (PVA) mold and UV curable poly-dimethylsiloxanes (PDMS) resin for continuous roll imprinting process. The PVA mold was chosen since it is flexible and can be dissolved in water. Since the PDMS can form thin SiO_x layer on the surface by oxygen plasma treatment, silane based hydrophobic anti-stiction layer can be formed directly on the surface of PDMS. As a result, nano-sized patterns were successfully formed on the flexible PET films by UV roll imprinting with the fabricated roll stamp.     

Novel transparent hybrid polymer working stamp for UV-imprinting

Transparent stamps are an integral and crucial part of the UV-imprinting. Time consuming fabrication of quartz stamps increases the price of the technology. In the presented work a thermally stable transparent imprint stamp made of a novel hybrid polymer system is demonstrated. As a low-cost and highly efficient alternative the hybrid polymer stamp contributes to the acceptance and application of the nanoimprint technology. By using the UV-patternable inorganic–organic hybrid polymer quartz stamps might become superfluous in the UV-imprint process entirely, because transparent working stamps can be manufactured also with use of opaque silicon master stamps.