Fabrication of Through Micro-hole Arrays in Silicon Using Femtosecond Laser Irradiation and Selective Chemical Etching

We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the chemical reaction of the femtosecond laser-induced structure change zone and hydrofluoric acid solution. The morphologies of the through micro-holes and micro-hole arrays are characterized by using scanning electronic microscopy, The effects of the pulse number on the depth and diameter of the holes are investigated. Honeycomb arrays of through micro-holes fabricated at different laser powers and pulse numbers are demonstrated.

Etching mask optimization of InAs/GaSb superlattice mid-wavelength infared 640×512 focal plane array

In this paper we focused on the mask technology of inductively coupled plasma（ICP） etching for the mesa fabrication of infrared focal plane arrays（FPA）.By using the SiO_2 mask,the mesa has higher graphics transfer accuracy and creates less micro-ripples in sidewalls.Comparing the IV characterization of detectors by using two different masks,the detector using the SiO_2 hard mask has the R_0A of 9.7×10~6 Ω·cm^2,while the detector using the photoresist mask has the R_0A of3.2 × 10~2 Ω·cm^2 in 77 K.After that we focused on the method of removing the remaining SiO_2 after mesa etching.The dry ICP etching and chemical buffer oxide etcher（BOE） based on HF and NH4 F are used in this part.Detectors using BOE only have closer R_0A to that using the combining method,but it leads to gaps on mesas because of the corrosion on AlSb layer by BOE.We finally choose the combining method and fabricated the 640×512 FPA.The FPA with cutoff wavelength of 4.8 μm has the average R_0A of 6.13 × 10~9 Ω·cm^2 and the average detectivity of 4.51 × 10~9 cm·Hz^（1/2）.W^（-1）at 77 K.The FPA has good uniformity with the bad dots rate of 1.21%and the noise equivalent temperature difference（NEDT） of 22.9 mK operating at 77 K.

Quantificational Etching of AAO Template

Ni nanowires were prepared by electrodeposition in porous anodized aluminum oxide （AAO） template from a composite electrolyte solution. Well-ordered Ni nanowire arrays with controllable length were then made by the partial removal of AAO using a mixture of phosphoric acid and chromic acid （6 wt pct H3PO4：1.8 wt pct H3CrO4）. The images of Ni nanowire arrays were studied by scanning electron microscopy （SEM） to determine the relationship between etching time and the length of Ni nanowire arrays. The results indicate that the length of nanowires exposed from the template can be accurately controlled by controlling etching time.

Etching-assisted femtosecond laser microfabrication

Although femtosecond laser microfabrication is one of the most promising three-dimensional（3D） fabrication techniques, it could suffer from low fabrication efficiency for structures with high 3D complexities. By using etching as a main assistant technique, the processing can be speeded up and an improved structure surface quality can be provided. However,the assistance of a single technique cannot satisfy the increasing demands of fabrication and integration of highly functional 3D microstructures. Therefore, a multi-technique-based 3D microfabrication method is required. In this paper, we briefly review the recent development on etching-assisted femtosecond laser microfabrication（EAFLM）. Various processing approaches have been proposed to further strengthen the flexibilities of the EAFLM. With the use of the multi-technique-based microfabrication method, 3D microstructure arrays can be rapidly defined on planar or curved surfaces with high structure qualities.

Charging Effect in Plasma Etching Mask of Hole Array

It has already been found that the round shape of holes can be changed into hexagonal shape during plasma etching processes.This work aims to understand the mechanism behind such a shape change using particle simulation method.The distribution of electric field produced by electrons was calculated for different heights from the mask surface.It is found that the field strength reaches its maximum around a hole edge and becomes the weakest between two holes. The field strength is weakened as moving away from the surface.The spatial distribution of this electric field shows obvious hexagonal shape around a hole edge at some distances from the surface. This charging distribution then affects the trajectories of ions that fall on a mask surface so that the round hole edge is etched to become a hexagonal hole edge.The changing of this hole shape will again alter the spatial distribution of electric field to enhance the charging effect dynamically.

Preparation of Electrode Array by Electrochemical Etching Based on FEM

Process technology of multiple cylindrical micro-pins by wire-electrical discharge machining （wire-EDM） and electrochemical etching was presented. A row of rectangular micro-columns were machined by wire-EDM and then machined into cylindrical shape by electrochemical etching. However, the shape of the multiple electrodes and the consistent sizes of the electrodes row are not easy to be controlled. In the electrochemical process, the shape of the cathode electrode determines the current density distribution on the anode and so the forming of multiple electrodes. This paper proposes a finite element method （FEM） to accurately optimize the electrode profile. The microelectrodes row with uniformity diameters with size from hundreds micrometers to several decades could be fabricated, and mathematical model controlling the shape and diameter of multiple microelectrodes was provided. Furthermore, a good agreement between experimental and theoretical results was confirmed.

Effect of KOH treatment on structural and photovoltaic properties of ZnO nanorod arrays

ZnO nanorod arrays （NRs） were synthesized on the fluorine-doped SnO2 transparent conductive glass （FTO） by a simple chemical bath deposition （CBD） method combined with alkali-etched method in potassium hydroxide （KOH） solution. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and current-voltage （I-V） curve were used to characterize the structure, morphologies and optoelectronic properties. The results demonstrated that ZnO NRs had wurtzite structures, the morphologies and photovoltaic properties of ZnO NRs were closely related to the concentration of KOH and etching time, well-aligned and uniformly distributed ZnO NRs were obtained after etching with 0.1 mol/L KOH for 1 h. ZnO NRs treated by KOH had been proved to have superior photovoltaic properties compared with high density ZnO NRs. When using ZnO NRs etched with 0.1 mol/L KOH for 1 h as the anode of solar cell, the conversion efficiency, short circuit current and open circuit voltage, compared with the unetched ZnO NRs, increased by 0.71%, 2.79 mA and 0.03 V, respectively.

Ordered silicon nanorod arrays with controllable geometry and robust hydrophobicity

Highly ordered silicon nanorod（Si NR） arrays with controllable geometry are fabricated via nanosphere lithography and metal-assisted chemical etching. It is demonstrated that the key to achieving a high-quality metal mask is to construct a non-close-packed template that can be removed with negligible damage to the mask. Hydrophobicity of Si NR arrays of different geometries is also studied. It is shown that the nanorod structures are effectively quasi-hydrophobic with a contact angle as high as 142°, which would be useful in self-cleaning nanorod-based device applications.

空间柔性阵列天线薄膜阵面制造技术研究

简要阐述了空间柔性天线的进展,分析了空间柔性天线薄膜阵面制造关键技术。研究了薄膜阵面电磁波传输金属薄膜制备技术、薄膜阵面图形化制造技术、薄膜阵面拼接用材料评价、薄膜阵面的裁切技术等。采用磁控溅射技术,通过溅射功率、走带张力、走带速度的调节,在有机柔性薄膜基材上镀制了不同厚度的金属铜膜,实现了有机柔性薄膜基材的表面金属化;利用飞秒激光刻蚀精度高,不损伤柔性薄膜基材的特点,获得了图形化的金属薄膜阵面单元;对3M92号胶带与改性聚酰亚胺胶接材料的拼接强度与耐高低温性能进行了试验对比,发现改性聚酰亚胺胶接材料的强度与耐高低温性能更好,更适合薄膜阵面的拼接;对比了用纳秒激光和飞秒激光裁切的薄膜微观形貌,结果表明,用飞秒激光裁切的切面光滑,无烧蚀与毛刺,适合于高精度薄膜阵面的制造。研究为空间柔性阵列薄膜天线的制造提供了大量的基础数据。

基于银纳米三角片蚀刻机制区分不同产地浓香型白酒

区分不同产地白酒对于产品质量控制和原产地保护具有重要意义。本研究以四种不同形貌大小的银纳米三角片(Ag nanoprism,AgNPRs)作为传感材料,两种金属离子和一种氧化阴离子作为氧化蚀刻剂,基于AgNPRs蚀刻机制构建了一种4×3传感阵列,将该阵列对四川、江淮和北方三大产地共41款代表性浓香型白酒样品进行比色响应,所获得的比色信号值通过线性判别分析(linear discriminant analysis,LDA)进行判别分析,并进一步选取了部分未知样品对判别模型进行了外部验证。比色响应机制研究结果表明,白酒样品对AgNPRs的蚀刻效应起促进作用,这可能与白酒中含有不同的有机酸有关。对不同产地样品的区分结果显示,单一阵列对不同产地样品的区分效果相对较低,三种阵列组合后的区分效果明显提高,对41个样品的产地判别率可达99%,对15个未知浓香型酒样的产地判别率可达98%。采用组合阵列对四川产地5种品牌21个样品和江淮产地3种品牌13个样品判别率分别可达99%和100%,采用单一阵列对四川各厂家不同等级产品的判别率均可达100%。本研究采用的纳米比色传感方法简便快速,不仅可用于产品鉴别和防伪,也可辅助用于生产过程质量监控,为白酒质量智能化监控奠定研究基础。

石英玻璃刻蚀浅锥孔阵列的工艺研究

介绍了石英玻璃刻蚀浅锥孔的制备方法。通过紫外接触式光刻系统在石英玻璃上形成光刻胶浅锥孔阵列图案,用电感耦合反应离子刻蚀机(ICP-RIE)进行刻蚀。研究了光刻参数和蚀刻参数(气体流量、气体成分、腔压、ICP功率和偏置功率)对石英玻璃的刻蚀性能、表面轮廓、蚀刻速率和侧壁倾角的影响。结果表明:刻蚀气体种类对石英浅锥孔阵列刻蚀效果有显著影响,CF_(4)和Ar的组合气体所刻蚀的石英锥孔阵列的效果最佳,随着CF_(4)气体流量比的增加,石英刻蚀倾角先降低后又小幅增加,当刻蚀气体(CF_(4)∶Ar)流量比在5∶3时,石英刻蚀速率为0.154μm/min,光刻胶刻蚀速率为0.12μm/min,得到的石英浅锥孔倾角最倾斜。在其他刻蚀参数一定的情况下,ICP功率由600W升高至800W,石英刻蚀速率大幅降低,聚合物的沉积成为刻蚀工艺的主导;刻蚀石英的粗糙度Rq随着ICP功率的降低明显增加;RF功率升高时刻蚀石英的速率增加,Rq值增加后又降低,当RF功率升高至200W时,光刻胶发生碳化现象。可为石英玻璃微器件的制备提供工艺参考。

界面钻蚀主导的准各向异性湿法刻蚀法制备玻璃微棱镜阵列

玻璃微棱镜具有耐腐蚀、耐高温、寿命长等优点,但在玻璃上加工微棱镜阵列目前仍是一个难题。因此,提出了界面钻蚀主导的玻璃准各向异性湿法刻蚀方法,制备了高质量的微棱镜阵列器件。在元胞自动机中引入界面性质调控,模拟了界面钻蚀与各向同性侧蚀的竞争行为,探究了刻蚀横截面形貌的变化规律,构建了准各向异性湿法刻蚀模型。在此指导下,加工了横截面为梯形的微结构,设计并制备了间距、形状、尺寸均可调控的微棱镜阵列,重复性达到98%。验证了微棱镜阵列对LED灯扩散效果,光亮度提升了4.6倍。本文改变了传统玻璃湿法刻蚀各向同性的固有认识,创新性地开发了准各向异性刻蚀工艺,为玻璃微棱镜阵列等相关器件提供了高效低成本的制备方法。

激光辅助制备有序孔钽箔及其电容性能研究

目的改善商业钽箔作为钽阳极材料时比容量有限的问题。方法提出了一种利用激光刻蚀技术和电化学腐蚀相结合的工艺在商业钽箔上构筑有序孔用于提升其储电能力的方法,对处理前后钽箔的表面形貌、结构特征以及电容性能发生的变化进行表征。结果利用15 V的电压阳极氧化处理预先在钽箔表面生长一层Ta_(2)O_(5),其具有的厚度更好地适应了1064nm激光的重复扫描。Ta_(2)O_(5)层在激光的作用下被有效去除,电子显微镜的表征结果显示,钽箔表面形成有序分布的阵列型微结构,为钽箔在电化学腐蚀过程中的孔生长提供了范围,这种独特的结构也为钽箔的电化学反应提供了更丰富的活性位点。比电容量的测试结果显示,有序孔钽箔在1mol/L的H2SO4电解质溶液中具有247.4n F/mm^(2)的优异面积比容量,与未处理的商业钽箔21.7nF/mm^(2)的面积比容量相比提升了近11.4倍。结论通过对商业钽箔进行特殊的孔结构设计,可以显著提升其作为电极时的比容量,利用激光刻蚀和电化学腐蚀的双重作用来控制钽箔上孔隙生长的有序性,有望为下一代钽电解电容器阳极材料的研究提供设计思路。

Influence of etching current density on the morphology of macroporous silicon arrays by photo-electrochemical etching

Macroporous silicon arrays（MSA） have attracted much attention for their potential applications in photonic crystals,silicon microchannel plates,MEMS devices and so on.In order to fabricate perfect MSA structure,photo-electrochemical （PEC） etching of MSA and the influence of etching current on the pore morphology were studied in detail.The current-voltage curve of a polished n-type silicon wafer was presented in aqueous HF using back-side illumination.The critical current density J_（PS） was discussed and the basic condition of etching current density for steady MSA growth was proposed.An indirect method was presented to measure the relation of J_（PS） at the pore tip and etching time.MSA growth was realized with the pore diameter constant by changing the etching current density according to the measuring result of J_（PS）.MSA with 295μm of depth and 98 of aspect ratio was obtained.

Influence of voltage on photo-electrochemical etching of n-type macroporous silicon arrays

The influence of voltage on photo-electrochemical etching（PEC） of macroporous silicon arrays（MSA） was researched.According to the theory of the space charge region,I-V scan curves and the reaction mechanism of the n-type silicon anodic oxidation in HF solution under different current densities,the pore morphology influenced by the working voltage were studied and analyzed in detail.The results show that increasing the etching voltage will lead to distortion of the pore morphology,decreasing etching voltage will result in an increase in the blind porosity, and the constant etching voltage for a long time will cause gradual bifurcation.Through the optimization of the process parameters,the perfect MSA structure with a pore depth of 317μm,a pore size of 3μm and an aspect ratio of 105 was obtained.

Disordered wall arrays by photo-assisted electrochemical etching in n-type silicon

The fabrication of ordered, high aspect-ratio microstructures in silicon by use of photo-assisted electrochemical etching is an important technology, where voltage and current density are significant factors. In this paper, disordered walls appear in 5-inch n-type silicon wafers when a large current density is used. Based on the theory of space charge region, these disordered walls are caused by the contradiction between the protection from dissolution by a high applied voltage and the dissolution by a high current density. To verify this point, wall arrays were fabricated at different applied voltages and current densities. Moreover, the critical voltage was kept constant and different current densities were applied to obtain conditions for avoiding disordered walls and achieving uniform wall arrays. Finally, a wall array with a period of 5.6 μm and a depth of 55 μm was achieved at an applied voltage of 3 V and a monotonically increasing current density ranging from 22.9 to 24.5 mA/cm^2.

HgCdTe探测列阵干法技术的刻蚀形貌研究

首次报道了HgCdTe微台面焦平面探测列阵成形工艺的干法刻蚀技术有关刻蚀形貌的一些研究结果.从HgCdTe外延材料的特点出发,详细分析了其干法刻蚀适用的RIE(reactive ion etching)设备和刻蚀原理.采用高等离子体密度、低腔体工作压力、高均匀性和低刻蚀能量的ICP(inductively coupled plasma)增强型RIE技术,研究了不同的工艺气体配比、腔体工作压力、ICP源功率和RF源功率对HgCdTe材料刻蚀形貌的影响,并初步得到了一种稳定的、刻蚀表面清洁、光滑、图形轮廓良好、均匀性较好和刻蚀速率较高的干法刻蚀工艺.

国产电阻阵列技术的发展趋势

回顾和总结了国产电阻阵列3个发展阶段的主要技术方案、优缺点和最终结果。第一代64×64电阻阵列采用了体材料微机械加工的单晶硅薄膜微型电阻,成品率较高但与CMOS工艺不兼容、均匀性差、功耗大、占空比极低、规模小;第二代128×128和256×256电阻阵列采用了体材料微机械加工的复合薄膜微型电阻,基本解决了工艺兼容性、均匀性、功耗等方面的问题,但占空比和规模提高有限;第三代128×128复合悬浮薄膜电阻阵列采用了薄膜转移技术,占空比显著提高,功耗明显下降,该技术有望成为今后国产电阻阵列的主流制造技术,但技术成熟度有待进一步提高。最后,对国产电阻阵列未来技术发展进行了展望、分析和探讨。

飞秒激光和酸刻蚀方法制作凹面微透镜阵列

基于飞秒激光光刻技术和氢氟酸对光学玻璃的刻蚀,在K9光学玻璃表面制作了凹面微透镜阵列,并且可以以此为模板实现凸微透镜阵列的大量复制.用相位对比显微镜和扫描电子显微镜分析了微透镜阵列的表面轮廓,测试了微透镜阵列的光学衍射特征.该方法简单、透镜参量可控,制作的微透镜阵列能够用于分光、光束匀化、并行光刻等强激光领域.

HgCdTe焦平面探测阵列干法技术的刻蚀速率研究

首次报道了HgCdTe焦平面探测器微台面列阵成形工艺的干法技术有关刻蚀速率的一些研究结果。从HgCdTe外延材料的特点出发,详细分析了其干法刻蚀适用的R IE(ReactiveIon Etching)设备、刻蚀原理以及刻蚀速率的影响因素。采用ICP(Inductively Coupled Plasma)增强型R IE技术,研究了一种标准刻蚀条件的微负载效应(etch lag)对刻蚀速率的影响,以及刻蚀非线性问题,并获得刻蚀速率随时间的关系。