Regulation of actin cytoskeleton via photolithographic micropatterning

Actin cytoskeleton plays crucial roles in various cellular functions.Extracellular matrix(ECM)can modulate cell morphology by remodeling the internal cytoskeleton.To define how geometry of ECM regulates the organization of actin cytoskeleton,we plated individual NIH 3T3 cells on micropatterned substrates with distinct shapes and sizes.It was found that the stress fibers could form along the nonadhesive edges of T-shaped pattern,but were absent from the opening edge of V-shaped pattern,indicating that the organization of actin cytoskeleton was dependent on the mechanical environment.Furthermore,a secondary actin ring was observed on 50μm circular pattern while did not appear on 30μm and 40μm pattern,showing a size-dependent organization of actin cytoskeleton.Finally,osteoblasts,MDCK and A549 cells exhibited distinct organization of actin cytoskeleton on T-shaped pattern,suggesting a cell-type specificity in arrangement of actin cytoskeleton.Together,our findings brought novel insight into the organization of actin cytoskeleton on micropatterned environments.

材料表面微图案结构成型技术及其研究进展

表面微图案结构成型技术作为实现材料表面纹理化并促进材料先进化、功能化的一种手段已经广泛应用到实际生产制造中。根据材料应用领域的差异,表面微图案成型的主要方法包括热压花、化学蚀刻、电火花加工、光刻和3D打印。本文综述了不同表面微图案结构成型技术及制备表面纹理化功能材料的基本原理,并列举其在光伏、电子信息、智能制造、超精密制造等领域的实际应用。总结了不同表面微图案结构成型技术的特点及适用范围,提出了实现材料表面纹理化和功能化所面临的关键问题,为表面微图案结构的微加工技术提供了一定参考。

单层石墨烯微米尺度图案化和功能化:调控电子传输特性

石墨烯具有优异的物理特性,如单原子厚度、极高的载流子迁移率等。然而,其零带隙的半金属特性限制了题在高性能场效应晶体管中的应用。为此,研究者们提出了石墨烯纳米化、外场诱导、掺杂以及化学图案化等策略,以调控其带隙宽度。但是,这些方法的可控性以及稳定性还需要进一步改善。在本研究中,我们提出采用电化学溴化并结合光刻图案化调控单层石墨烯的电子传输特性,通过这种方法,成功制备了图案化的溴化石墨烯(SLGBr)。进一步研究表明,单层石墨烯的电子传输性能可以通过溴化程度来调控。当溴化程度较小时,SLGBr表现为电阻特性,且其电导随溴化程度增加而减小;当溴化程度增加到一定值时,SLGBr表现为与半导体类似的特性。本研究将为全石墨烯器件的制备提供可行的技术路线,拓展其在微电子领域的应用。

无铅焊接中Lift-off现象产生的原因及抑制对策

本文首次提出三要素法来解释Lift-off的形成机理。相比传统的“Bi-Segregation”失效机理,“三要素法”可以解释含Bi和不含Bi的所有无铅钎料产生或不产生Lift-off的原因,并由此找出了Lift-off的抑制对策。

Twisted Integration of Complex Oxide Magnetoelectric Heterostructures via Water‑Etching and Transfer Process

Manipulating strain mode and degree that can be applied to epitaxial complex oxide thin films have been a cornerstone of strain engineering.In recent years,lift-off and transfer technology of the epitaxial oxide thin films have been developed that enabled the integration of heterostructures without the limitation of material types and crystal orientations.Moreover,twisted integration would provide a more interesting strategy in artificial magnetoelectric heterostructures.A specific twist angle between the ferroelectric and ferromagnetic oxide layers corresponds to the distinct strain regulation modes in the magnetoelectric coupling process,which could provide some insight in to the physical phenomena.In this work,the La_(0.67)Sr_(0.33)MnO_(3)(001)/0.7Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.3PbTiO_(3)(011)(LSMO/PMN-PT)heterostructures with 45.and 0.twist angles were assembled via water-etching and transfer process.The transferred LSMO films exhibit a fourfold magnetic anisotropy with easy axis along LSMO<110>.A coexistence of uniaxial and fourfold magnetic anisotropy with LSMO[110]easy axis is observed for the 45°Sample by applying a 7.2 kV cm^(−1)electrical field,significantly different from a uniaxial anisotropy with LSMO[100]easy axis for the 0°Sample.The fitting of the ferromagnetic resonance field reveals that the strain coupling generated by the 45°twist angle causes different lattice distortion of LSMO,thereby enhancing both the fourfold and uniaxial anisotropy.This work confirms the twisting degrees of freedom for magnetoelectric coupling and opens opportunities for fabricating artificial magnetoelectric heterostructures.

低温砷化镓的外延lift-off和范德华贴附研究

研究了低温砷化镓的外延lift-off和基于范德华力在石英新衬底上贴附的实验方法：腐蚀掉100nm厚的AlAs牺牲层，将外延生长的500nm厚的低温砷化镓（LT-GaAs）从生长衬底上揭下（lift-off），借助于范德华力将LT-GaAs外延膜贴附在新衬底上。Lift—off之前在LT-GaAs表面上滴附黑蜡，以增强在lift-off过程中对LT-GaAs的保护，和加快反应气体扩散离开反应区的过程。针对500nm厚的LT-GaAs外延薄膜的揭起和贴附，给出了低温砷化镓的最佳lift-off尺寸和提高范德华力贴附质量的实验技术。此外还给出了利用所得到的lift-off后的LT-GaAs制备的共平面条形结构光导开关的时间特性：上升时间小于1．5ps，FWHM小于2ps。

光刻法制备正方薄片状粒子及其识别算法优化

非球形胶体粒子在凝聚态物理、新型智能材料研发等领域均具有重要的研究价值,其中,正方薄片状胶体粒子由于具有形状简单、可周期性密铺、自组装形成的结构多样等特点,得到了广泛关注。采用光刻法制备了SU-8环氧树脂正方薄片状胶体粒子,粒子的平均边长为2.3μm、平均厚度为1.2μm,顶点在光刻精度影响下,发生小幅度圆角化。通过分析光刻前后粒子的红外吸收光谱发现,光刻后,粒子内部的SU-8环氧树脂交联程度较高。通过计算粒子相互作用势与粒子间距离的关系,证明了粒子间的相互作用为近硬球相互作用。同时,基于正方薄片状胶体粒子在平面及球面的单粒子运动图像,提出了一种新的粒子顶点识别算法,该算法可以避免由图像不清晰导致的粒子错误识别问题。

Sand particle lift-off velocity measurements and numerical simulation of mass flux distributions in a wind tunnel

Lift-off velocity of saltating sand particles in wind-blown sand located at 1.0 mm above the sand bed surface was measured using a phase Doppler particle analyzer in a wind tunnel. The results show that the probability distribution of lift-off velocity can be expressed as a lognormal function, while that of lift-off angle follows an exponential function. The probability distribution of lift-off angle conditioned for each lift-off velocity also follows an exponential function, with a slope that becomes steeper with increasing lift-off velocity. This implies that the probability distribution of lift-off velocity is strongly dependent on the lift-off angle. However, these lift-off parameters are generally treated as an independent joint probability distribution in the literature. Numerical simulations were carried out to investigate the effects of conditional versus independent joint probability distributions on the vertical sand mass flux distribution. The simulation results derived from the conditional joint probability distribution agree much better with experimental data than those from the independent ones. Thus, it is better to describe the lift-off velocity of saltating sand particles using the conditional joint probability distribution. These results improve our understanding of saltation processes in wind-blown sand.

Design of Microstructure Parameters on a Small Multi-Throttle Aerostatic Guideway in Photolithography

A compact multi-throttle aerostatic guideway is the preferred structure for high precision and acceleration motion in the variable-slit system(VS)of photolithography.The presence of microstructure,such as recesses and grooves,on the guideway working surface has been found to improve the loading performance.Nevertheless,the effects on the guideway performance of changing the microstructure on the micron level are not yet clear.The mesh adaptation method,which was proposed by the authors,is employed in this paper to quantitatively study the influences of four microstructure parameters.The effect of tuning these parameters on the loading performance is revealed.The level of impact determines the proposed design process of the parameters.The characteristic feature of the proposed design process is that the working points of carrying capacity,stiffness,and rotational stiffness are unified under twoway adjusting by means of recess parameters.According to the proposed design process and tuning method,the restriction of supply pressure is lifted to a certain extent and the mutual tradeoff among the loading performances is relieved.The experimental results show that the rotational stiffness of the designed guideway,based on the tuned parameters,reached 2.14×10^(4) Nmrad1 and increased by 69.8%.In a scanning test of the applied VS on argon fluoride laser(ArF)photolithography,the average scanning acceleration reached 67.5 m·s^(-2),meeting the design specification.

Experimental analysis of sand particles' lift-off and incident velocities in wind-blown sand flux

The probability distributions of sand particles＇ lift-off and incident velocities in a wind-blown sand flux play very important roles in the simulation of the wind-blown sand movement. In this paper, the vertical and the horizontal speeds of sand particles located at 1.0 mm above a sand-bed in a wind-blown sand flux are observed with the aid of Phase Doppler Anemometry （PDA） in a wind tunnel. Based on the experimental data, the probability distributions of not only the vertical lift-off speed but also the lift-off velocity as well as its horizontal component and the incident velocity as well as its vertical and horizontal components can be obtained by the equal distance histogram method. It is found, according to the results of the X^2-test for these probability distributions, that the probability density functions （pdf＇s） of the sand particles＇ lift-off and incident velocities as well as their vertical com- ponents are described by the Gamma density function with different peak values and shapes and the downwind incident and lift-off horizontal speeds, respectively, can be described by the lognormal and the Gamma density functions, These pdf＇s depend on not only the sand particle diameter but also the wind speed.

国产Lift-Off光刻胶在空间用太阳电池中的应用

选用两种较为典型的国产Lift-Off光刻胶(A和B)进行了实验优化,并进行了电极蒸镀后的牢固度测试、电致发光测试和电性能测试。在牢固度测试中发现,A电池样品有掉栅现象,B电池样品没有出现掉栅现象。通过EL测试和电性能测试分析证明,A电池的电极与太阳电池基体存在局部的接触不良现象。通过实验筛选出了一种应用前景较好的B型号国产Lift-Off负性光刻胶,有望经过进一步验证和优化后逐步应用在空间用太阳电池生产中。

Modeling of photolithography process in semiconductor wafer fabrication systems using extended hybrid Petri nets

To describe a semiconductor wafer fabrication flow availably, a new modeling method of extended hybrid Petri nets (EHPNs) was proposed. To model the discrete part and continuous part of a complex photolithography process, hybrid Petri nets (HPNs) were introduced. To cope with the complexity of a photolithography process, object-oriented methods such as encapsulation and classifications were integrated with HPN models. EHPN definitions were presented on the basis of HPN models and object-oriented methods. Object-oriented hybrid Petri subnet models were developed for each typical physical object and an EHPN modeling procedure steps were structured. To demonstrate the feasibility and validity of the proposed modeling method, a real wafer photolithography case was used to illustrate the modeling procedure. The modeling results indicate that the EHPNs can deal with the dynamic modeling of a complex photolithography process effectively.

Synthesis of New Binder Polymers for Photolithographic Patterning of Black Pixel Define Layers of Organic Light Emitting Diode

The fabrication of black pixel define layer (PDL) on the organic light emitting diode (OLED) panel has been developed actively by using negative-tone black photoresist which contain photoinitiator, photosensitizer, binder polymer, multifunctional monomer and black mill base in order to improve the outdoor visibility of OLEDs. Cardo type binder polymer containing bulky and rigid fluorene group has been widely used in the black photoresist formulation. However, the commercial cardo binder polymer has high cost and requires high UV dose for the fine patterning of PDL in the photolithographic process. In this study we designed and synthesized various non-cardo type binder polymers and evaluated the new binder polymers in comparison with the cardo binder polymer for the improved patterning of PDL on the OLED panel.

萘酚基酚醛树脂的合成及其在lift-off光刻胶中的应用

首先以α-萘酚、间甲酚、甲醛为单体,通过缩聚反应合成了萘酚基酚醛树脂NAPR,随后与二碳酸二叔丁酯(DBDC)反应制备了一系列t-BOC改性的萘酚基酚醛树脂NAPR-BOC。用红外(FT-IR)、核磁(1 H NMR)、凝胶色谱(GPC)、热失重分析(TGA)对其结构及性能进行了表征。以NAPR-BOC-2为基体树脂配制成lift-off光刻胶,测试了光刻胶的分辨率、形貌和耐热性,得到的光刻胶分辨率最大为0.6μm,耐热可达130℃。

Epitaxial Lift-Off of Flexible GaN‑Based HEMT Arrays with Performances Optimization by the Piezotronic Effect

High-electron-mobility transistors(HEMTs)are a promising device in the field of radio frequency and wireless communication.However,to unlock the full potential of HEMTs,the fabrication of large-size flexible HEMTs is required.Herein,a large-sized(>2 cm^(2))of AlGaN/AlN/GaN heterostructure-based HEMTs were successfully stripped from sapphire substrate to a flexible polyethylene terephthalate substrate by an electrochemical lift-off technique.The piezotronic effect was then induced to optimize the electron transport performance by modulating/tuning the physical properties of two-dimensional electron gas(2DEG)and phonons.The saturation current of the flexible HEMT is enhanced by 3.15%under the 0.547%tensile condition,and the thermal degradation of the HEMT was also obviously suppressed under compressive straining.The corresponding electrical performance changes and energy diagrams systematically illustrate the intrinsic mechanism.This work not only provides in-depth understanding of the piezotronic effect in tuning 2DEG and phonon properties in GaN HEMTs,but also demonstrates a low-cost method to optimize its electronic and thermal properties.

光刻-刻蚀虚拟仿真实验的设计与实施

对焦国家中国芯开发战略,自主设计开发光刻-刻蚀虚拟仿真实验。实验以芯片生产过程中的光刻-刻蚀工艺作为代表,通过虚拟仿真技术进行设备建模、光路模拟、微观粒子运动演示等,将无法触及的设备内部结构、复杂的光刻-刻蚀工艺影响、转瞬即逝的微观实验现象直观化展示给实验者,利用“练习模式”和“考试模式”让实验者充分开展实验探索,通过不同模拟情境激发学生学习兴趣。实验解决了光刻-刻蚀实验在高校难以开展的问题,为综合型人才培养打下基础。

基于专利数据的全球光刻技术竞争态势研究

通过对德温特创新平台数据库中收录的光刻技术领域的专利数据进行分析,从专利整体环境、技术布局和机构竞争3个方面,探讨全球光刻技术的技术竞争态势。研究结果表明:全球光刻领域专利族数量仍呈现逐年递增的趋势,中国近几年技术研发活跃度较高,但与技术原始积累较强的美、日相比仍有较大差距;研究热点围绕极紫外光刻技术呈发散式分布;全球范围内,各国机构科研活动的内部集聚性明显,外部技术壁垒由日、美等技术领先国家搭建,形成局部技术锁定。因此,中国在光刻方面必须把握国家科技转型发展机遇期,敏锐感知技术发展趋势以提前布局,理论研究与应用研究协同推进,加快构建以国内合作为主、以国际合作为辅的新型合作组织及治理机制。

高铝玻璃基聚四氟乙烯镀膜微槽模具的研究

针对当前微槽模具压印中粘接和纹路变形问题,本文以高铝玻璃为基体,把光刻、刻蚀、镀膜等半导体芯片制造技术,用于微槽模具的制备。结果表明,与Eu胶微槽模具相比,镀聚四氟乙烯膜的高铝玻璃模具的寿命提高了40%,压印的产品轮廓清晰,成形精度高,成品率也提高了3个百分点。制造微槽模具的聚四氟乙烯,发挥了结构性作用。制成的模具也可用于压制其他金属与非金属表面的微观装饰图案等。

电感耦合等离子刻蚀法加工石英晶体谐振器工艺研究

为了制备石英晶体谐振器,在石英衬底上采用光刻和电感耦合等离子刻蚀技术制备台阶形貌,研究了制备过程中激励电源功率、偏压电源功率以及导热物质等工艺参数对刻蚀效果的影响。并且利用扫描电子显微镜对刻蚀图形的表面形貌进行了观察,通过实验与分析得到了符合工业生产要求的工艺参数。最后在最优工艺参数条件下,制得了高约22μm的整齐的台阶形貌,并将干法刻蚀的结果与湿法刻蚀对比,展现了干法刻蚀的特点以及干法刻蚀应用于工业化生产石英晶体谐振器的潜力。