Nanoimprinting lithography on 200 mm wafers for optical applications

This paper presents how nanoimprint lithography is developed on 200 mm wafers for the fabrication of two optical devices: parts for optical encoders and organic light emitting diodes with enhanced light extraction efficiency. The optimization of the printing process is shown for both applications. Special studies are presented on the development of etching processes. The removing of the residual layer still needs efforts to guarantee the fidelity of the final patterns but we demonstrated that specific plasma chemistry leads to a high control of the pattern size during this etching step. It is even proved that an over-etch can be performed with no change of the structure dimensions. Final structures duplicated in Si or SiO₂ are then presented.     

High‐Resolution Nanoimprinting with a Robust and Reusable Polymer Mold

High temperature nanoimprinting of viscous polymers which are glassy at room temperature is usually performed using brittle and expensive molds made of inorganic materials. As a replacement, soft molds made of plastics or elastomers have been used because of their low cost and ease of fabrication. However, the deformation of polymer molds under pressure remains a major issue which limits their resolution in high temperature nanoimprinting. Moreover, the replicated structures are often broken or lack definition due to sticking of the embossed polymer to the mold. We report a method for imprinting fine, densely packed nanostructures down to 12 nm into a wide range of technologically important polymers using a flexible and robust mold made from ethylene(tetrafluoroethylene) (ETFE). The high resolution achieved is due to the mold's mechanical stability and resistance to distortion at high pressures and high temperatures. The flexibility and low surface energy of ETFE provide a clean mold release without fracture or deformation of the embossed structures. Multiple imprinting and patterning on large areas is also made possible because of the good conformal contact and low‐adhesion of the ETFE mold. Finally, this simple and inexpensive method allows reproduction of the stamps from one single master, thus providing an economical alternative to expensive and brittle inorganic materials.     

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。     

Anodized Aluminum Oxide/Polydimethylsiloxane Hybrid Mold for Roll‐to‐Roll Nanoimprinting

Two types (hard and soft) of the molds are widely used in nanoimprint lithography for a high throughput over a large area, and high‐resolution parallel patterning. Although hard molds have proven excellent resolutions and can be used at high temperatures, cracks often occur in the mold in addition to the requirement of high imprinting pressure. On the other hand, though soft molds can operate at lower pressures, they give poor pattern resolution. Here, a novel hybrid mold of anodized aluminum oxide (AAO) template attached to a flexible polydimethylsiloxane (PDMS) plate is introduced. Due to the flexible nature of PDMS, various polymer nanostructures are obtained on flat and curved substrates without crack formation on the AAO mold surface. Furthermore, the hybrid mold is successfully used for roll‐to‐roll imprinting for the fabrication of high density array of various shaped polymeric nanostructures over a large area.     

Use of Reversal Nanoimprinting of Nanoparticles to Prepare Flexible Waveguide Sensors Exhibiting Enhanced Scattering of the Surface Plasmon Resonance

A flexible surface plasmon resonance (SPR)‐based scattering waveguide sensor is prepared by directly imprinting hollow gold nanoparticles (NPs) and solid gold NPs onto flexible polycarbonate (PC) plates—without any surface modification—using a modified reversal nanoimprint lithography technology. Controlling the imprinting conditions, including temperature and pressure, allows for the fine adjustment of the depths of the embedded metal NPs and their SPR properties. This patterning approach exhibits a resolution down to the submicrometer level. A 3D finite‐difference time domain simulation is used to examine the optical behavior of light propagating parallel to the air/substrate interface within the near‐field regime. Consistent with the simulations, almost an order of magnitude enhancement in the scattering signal after transferring the metal NPs from the glass mold to the PC substrate is obtained experimentally. The enhanced signal is attributed to the particles' strong scattering of the guiding‐mode waves (within the waveguide) and the evanescent wave (above the waveguide) simultaneously. Finally, the imprinting conditions are optimized to obtain a strongly scattering bio/chemical waveguide sensor.     

Efficient and Flexible Thin Film Amorphous Silicon Solar Cells on Nanotextured Polymer Substrate Using Sol–gel Based Nanoimprinting Method

The mechanical flexibility of substrates and controllable nanostructures are two major considerations in designing high‐performance, flexible thin‐film solar cells. In this work, we proposed an approach to realize highly ordered metal oxide nanopatterns on polyimide (PI) substrate based on the sol‐gel chemistry and soft thermal nanoimprinting lithography. Thin‐film amorphous silicon (a‐Si:H) solar cells were subsequently constructed on the patterned PI flexible substrates. The periodic nanopatterns delivered broadband‐enhanced light absorption and quantum efficiency, as well as the eventual power conversion efficiency (PCE). The nanotextures also benefit for the device yield and mechanical flexibility, which experienced little efficiency drop even after 100,000 bending cycles. In addition, flexible, transparent nanocone films, obtained by a template process, were attached onto the patterned PI solar cells, serving as top anti‐reflection layers. The PCE performance with these dual‐interfacial patterns rose up to 8.17%, that is, it improved by 48.5% over the planar device. Although the work was conducted on a‐Si:H material, our proposed scheme can be extended to a variety of active materials for different optoelectronic applications.     

含磷环氧树脂的研究进展

综述了含磷环氧树脂的现状和未来发展趋势,介绍了国内外含磷环氧树脂的研究进展和目前的制造方法以及在覆铜板中的应用技术,通过含磷化合物把磷元素引入环氧树脂结构中制得含磷阻燃环氧树脂,具有阻燃性能好、热稳定性好、对固化物性能影响小、燃烧过程中有少烟、低毒、低热释放,环保等性能。     

电子封装用环氧树脂基复合材料的优化

研究了593固化剂不同用量加入电子封装用环氧树脂E-51中的效果,以及在E-51,Al2O3复合材料中硅烷偶联剂不同用量的效果,结果显示:593固化剂与环氧树脂质量比为1:4时,复合材料的致密度高,气孔少,成型效果好;当硅烷偶联剂KH-560质量分数为8%时,复合材料的热导率达到0.75 W/(m·K).     

Molecular dynamics approach to structure-property correlation in epoxy resins for thermo-mechanical lifetime modeling

This paper addresses the potential of molecular dynamics simulation for structure-property correlations in epoxy-resins. This is an important topic within a multi-scale framework to lifetime prediction in electronic packaging. For that purpose, epoxy-resins with small systematic variations in chemical structure have been synthesised and then characterised by various thermo-mechanical testing methods. It was found that moisture diffusion showed the greatest response with respect to material and loading parameters such as polarity, free volume, moisture concentration and temperature. Based on a parametric study, modeling approaches of various complexity have been able to show first qualitative but then also quantitative agreement. The paper comments further on the accuracy and limits of the method and correlates the calculations with experimental structural analysis results.     

电子显微镜技术表征树脂中橡胶相的显微结构形态

本文采用染色和化学刻蚀技术,通过透射电子显微镜(TEM)和扫描电子显微镜(SEM)对ABS树脂、高抗冲聚苯乙烯(HIPS)树脂、乙丙共聚聚丙烯SPl79、AWl91树脂中橡胶相的显微结构形态进行表征.结果表明,当树脂中橡胶相含双键时,采用硫化染色和四氧化锇(OsO4)染色技术,均能观察到树脂中橡胶相的显微结构形态,且采...     

双酚A型及苯酚型酚醛环氧树脂的对比研究

对比研究双酚A型酚醛环氧树脂(BPANE)与苯酚型酚醛环氧树脂(PNE)的反应动力学,及其在覆铜板中的应用性能。     

Mechanical and wetting properties of epoxy resins: Amine-containing epoxy-terminated siloxane oligomer with or without reductant

The mechanical and wetting properties of the diglycidyl ethers of bisphenol A (DGEBA) and bisphenol F (DGEBF) with epoxy-terminated siloxane oligomers (ETSO) were investigated to examine their durabilities as anisotropic conductive adhesive (ACA) resins. The mechanical properties were improved by decreasing the ETSO content due to the high cross-linking density resulting from the short-chain length of ETSO-diaminodiphenylmethane (DDM). To obtain good wettability in both systems, a short-chain reductant (butanoic acid, BA) was added. DGEBF produced enhancement in the wetting angle compared to that of DGEBA due to its low viscosity. DGEBF can be considered an eco-friendly material in this process since it does not require the use of other chemicals, such as a diluent. Therefore, DGEBF/ETSO-DDM with reductant constitutes a suitable system for favorable environmental processing.