UV-LIGA深度光刻机平滑衍射技术研究

UV-LIGA深度光刻技术是加工微型机电系统的一项重要的微细加工技术。介绍了一种平滑衍射效应的位错强度叠加原理，它采用了蝇眼积分透镜去平滑衍射，并模拟数值计算了硅片表面的光强分布，最后给出了光刻结果。     

SU-8胶微结构的显影技术研究

突破了传统深宽比概念,提出金属基底上基于图形特征的光刻胶显影技术,对采用SU-8胶加工高分辨率和高深宽比微结构的显影工艺进行了讨论,分析了120～340μm厚具有不同图形特征的SU-8胶显影规律,认为在同样条件下,凸型图形显影效果优于凹型非连通性图形;曲线型显影效果优于直线型图形与点状图形;圆弧连接的图形显影效果优于尖角型图形。显影时辅助适当功率的超声搅拌显著改善图形质量,凸型结构最佳超声功率小于10W;凹型结构超声功率为15W左右;深宽比为5～7的凸型胶膜结构适宜显影时间为10min以内,凹型结构显影时间达25min。     

模糊神经网络在UV-LIGA工艺优化中的应用

将模糊神经网络理论和算法应用于负性光刻胶(SU-8)加工高分辨率和高深宽比微结构的工艺研究,在正交试验的基础上对网络进行训练,建立了光刻图形质量与前烘时间、前烘温度、曝光量、后烘时间之间的预测模型。该模型采用五层前向模糊神经网络,学习算法为梯度下降法。进行了实验,实验结果表明,前烘温度与前烘时间对光刻质量影响最大。对120~340 μm厚的光刻胶,前烘温度取95℃,前烘时间100 min时,图形的相对线宽差最小;超声搅拌能缩短显影时间,显著改善图形质量,试验结果与计算结果十分吻合。将模糊神经网络应用于UV－LIGA工艺中,能实现光刻加工微结构的工艺参数优化。     

Fabrication of Fuze Micro-electro-mechanical System Safety Device

Fuze micro-electro-mechanical system(MEMS) has become a popular subject in recent years.Studies have been done for the application of MEMS-based fuze safety and arm devices.The existing researches mainly focused on reducing the cost and volume of the fuze safety device.The reduction in volume allows more payload and,thus,makes small-caliber rounds more effective and the weapon system more affordable.At present,MEMS-based fuze safety devices are fabricated mainly by using deep reactive ion ething or LIGA technology,and the fabrication process research on the fuze MEMS safety device is in the exploring stage.In this paper,a new micro fabrication method of metal-based fuze MEMS safety device is presented based on ultra violet(UV)-LIGA technology.The method consists of SU-8 thick photoresist lithography process,micro electroforming process,no back plate growing process,and SU-8 photoresist sacrificial layer process.Three kinds of double-layer moveable metal devices have been fabricated on metal substrates directly with the method.Because UV-LIGA technology and no back plate growing technology are introduced,the production cycle is shortened and the cost is reduced.The smallest dimension of the devices is 40 μm,which meets the requirement of size.To evaluate the adhesion property between electroforming deposit layer and substrate qualitatively,the impact experiments have been done on the device samples.The experimental result shows that the samples are still in good condition and workable after undergoing impact pulses with 20 kg peak and 150 μs duration and completely met the requirement of strength.The presented fabrication method provides a new option for the development of MEMS fuze and is helpful for the fabrication of similar kinds of micro devices.     

Multi-layer microstructure fabrication by combining bulk silicon micromachining and UV-LIGA technology

A novel method for fabrication of multi-layer microstructures of microelectro-mechanical system (MEMS) devices is described. This technique, which combines bulk silicon micromachining technique and UV-LIGA technique can overcome some shape limitations of single technique on complex microstructures. To demonstrate this combination, the SU-8 microstructure fabricated in the etched silicon grooves is presented. In this fabrication process, a SU-8 removal method by fuming sulfuric acid was introduced and a novel type of plastics PETG was tried in microhot embossing process. The proposed fabrication process can be applied to fabricating a high-aspect-ratio microstructure for a large displacement actuator and precision sensors. Moreover, this combined process enables the fabrication of more complex structures, which cannot be fabricated by bulk micromachining or UV-LIGA alone.     

一种三维金属微型腔的组合加工方法

为了制作局部为三维结构的金属模具微型腔,实验研究了一种组合加工新工艺,即先用紫外线光刻和电铸成形（准LIGA）技术在模具基底上制作二维金属微型腔,再用微细电火花成形加工（EDM）技术对微型腔的局部进行修形,得到局部为三维结构的微型腔,电火花修形的位置根据微型腔结构的设计要求而定．以制作聚合物微流控芯片用的金属模具为试件,以微细电火花成形加工中影响工件表面粗糙度的因素分析为理论指导,应用该方法制作了局部侧壁倾斜的三维微型腔．根据测量结果,两边侧壁与水平方向的夹角分别为49．6°和46．4°,倾斜侧壁的表面粗糙度Rs为0．391μm．     

UV-LIGA制作超高微细阵列电极技术

采用UV-LIGA技术制作了超高金属微细阵列电极,并利用电解置桩的方法辅助去除SU-8胶。通过单次涂胶和提高前烘温度、降低后烘温度的方法制作了厚度达1mm的SU-8胶结构;采取反接电极法在金属基底上电解得到微坑,增强电铸金属电极与金属基底的结合力,保证去胶后电铸金属的完整性。选取优化的工艺参数:单次注射式涂胶,前烘110℃/12h,适量曝光剂量,分步后烘50℃/5min、70℃/10min、90℃/30min,反接电极电解10V/15min等,获得了高900μm、线宽300μm的金属微细阵列电极结构。试验表明,UV-LIGA技术是一种高效、经济的制造超高微细阵列电极的有效手段。     

UV-LIGA光刻设备研究

近几年来微型机电系统 (MEMS)的研究得到了高速的发展 ,而MEMS的工艺基础是微细加工技术。针对电铸 (LIGA)技术所存在的缺点提出了紫外光电铸(UV -LIGA)技术 ,并研制了用于UV -LIGA技术的光刻设备。其中介绍了整机的设计要点、所解决的关键单元技术和实验结果。     

UV-LIGA和微细电火花加工技术组合制作三维金属微结构的研究

研究了UV-LIGA和微细电火花加工技术组合制作三维金属微结构的工艺方法。首先通过UV-LIGA制作二维金属微结构,再对该微结构进行微细电火花加工得到三维金属微结构。该方法具有加工精度高、可实现自由曲面三维金属微结构制作的优点。制作出了局部为梯形凸台和锥形凹槽三维微结构的镍模具。分析了微细电火花加工中放电参数对表面粗糙度的影响,通过减小放电电压和电容的方法降低了表面粗糙度。     

在金属基底上制作高深宽比金属微光栅的方法

根据光学领域对高深宽比金属微器件的需求,利用UV-LIGA工艺在金属基底上制作了具有高深宽比的金属微光栅。采用分层曝光、一次显影的方法制作了微电铸用SU-8胶厚胶胶模,解决了高深宽比厚胶胶模制作困难的问题。由于电铸时间长易导致铸层缺陷,故采取分次电铸等措施得到了电铸光栅结构;同时通过线宽补偿的方法解决了溶胀引起的线宽变小问题。在去胶工序中,采用"超声-浸泡-超声"循环往复的方法。最终,制作了周期为130μm、凸台长宽高为900μm×65μm×243μm的金属微光栅,其深宽比达到5,尺寸相对误差小于1%,表面粗糙度小于6.17nm。本文提出的工艺方法克服了现有方法制作金属微光栅时高度有限、基底易碎等局限性,为在金属基底上制作高深宽比金属微光栅提供了一种可行的工艺参考方案。