SU-8厚胶精密整平关键技术研究

发布时间：2018-12-30 16:54

【摘要】：LIGA和准LIGA加工工艺因其具有高深宽比、加工精度高等特点而被广泛应用于非硅MEMS器件加工中。SU-8胶是准LIGA工艺中常用胶，其表面的平整度直接影响其光刻精度。大尺寸（4T）SU-8厚胶（简称：厚胶）因其流动性较差，导致涂胶后表面平整度差，很难满足准LIGA光刻要求，并且目前关于厚胶整平设备及整平工艺的研究尚处于初级阶段。因此，研究厚胶整平工艺技术及装备具有重要意义和应用前景。本文以SU-8胶作为研究对象，重点开展高精度厚胶整平设备总体技术研究和厚胶整平工艺模拟实验研究，具体内容如下：（1）首先，对SU-8胶的特性、涂胶后表面问题、厚胶整平需求等进行了分析，并预测了厚胶的切削性能；其次，基于厚胶的平面度要求，提出采用飞刀铣削加工方法实现厚胶表面整平，并分别对加工中可能出现的加工误差和难点进行预测；最后，综合考虑整平精度和整平成本，分别对厚胶整平技术和厚胶整平设备性能提出了指标要求，为后续厚胶整平设备的总体方案研究奠定基础。（2）开展了厚胶整平设备的总体技术研究。首先，阐述了飞刀对称铣削加工原理、飞刀铣削刀具以及加工工艺流程安排；其次，提出了厚胶基片无损夹持方法、厚胶整平设备精度保证方案、设备控制方案、冷却和润滑方案；最后对厚胶整平设备的整体结构进行了设计及对关键外购件进行选型。（3）开展了厚胶整平设备关键结构设计与优化。开展了均布微细吸附力与吸附板优化设计，通过有限元建模与计算分析，，获得无损夹持吸附板的关键设计参数，为真空吸附夹具的设计奠定基础；同时，对整平设备刀盘结构进行优化设计和模态分析。（4）开展了厚胶整平设备动静态特性分析。对两种方案的设备结构进行模态分析，给出各阶模态振型和频率，并对比方案的优缺点；对最优设备方案进行静力学分析，研究结构在重力和负荷作用下的静变形，为设备结构细化设计提供参考和指导。（5）开展了厚胶整平机加工机理分析并完成厚胶整平模拟实验。首先，构建飞刀铣削加工切削力模型并对其切削力进行理论计算；其次，建立刀尖相对运动轨迹方程，对飞刀切削加工表面形貌进行了初步探讨；最后在现有的高精度车铣复合加工中心上开展厚胶切削模拟实验，探索刀具、背吃刀量、切削进给速度、主轴转速对厚胶的表面质量的影响情况，获得了厚胶的切削优化参数。
[Abstract]:LIGA and quasi LIGA processing processes are widely used in non-silicon MEMS devices because of their high aspect ratio and high machining accuracy. SU-8 adhesives are commonly used in quasi-LIGA process, and their surface smoothness directly affects their lithography accuracy. Due to the poor fluidity of large size (4T) SU-8 thick adhesive, it is difficult to meet the requirements of quasi LIGA lithography due to its poor surface smoothness. Therefore, it is of great significance and application prospect to study the technology and equipment of thick glue leveling. In this paper, SU-8 adhesive is taken as the research object, and the overall technology of high precision thick glue leveling equipment and the simulation experiment research of thick glue leveling process are carried out. The specific contents are as follows: (1) first, the characteristics of SU-8 glue are discussed. The surface problems after coating and the requirement of leveling of thick glue were analyzed, and the cutting performance of thick adhesive was predicted. Secondly, based on the flatness requirement of thick rubber, the flying cutter milling method is put forward to realize the surface leveling of thick glue, and the possible machining errors and difficulties in machining are forecasted. Finally, considering the leveling precision and the leveling cost synthetically, the paper puts forward the index requirements for the thick glue leveling technology and the performance of the thick glue leveling equipment respectively, which lays the foundation for the following research of the overall scheme of the thick glue leveling equipment. (2) the overall technology research of thick glue leveling equipment is carried out. Firstly, the principle of symmetrical flying cutter milling, the cutting tool of flying cutter and the arrangement of machining process are described. Secondly, the non-destructive clamping method of thick rubber substrate, the precision assurance scheme of thick glue leveling equipment, the equipment control scheme, cooling and lubrication scheme are put forward. Finally, the overall structure of thick glue leveling equipment is designed and the key parts purchased out are selected. (3) the key structure design and optimization of thick glue leveling equipment are carried out. Through finite element modeling and calculation analysis, the key design parameters of non-destructive clamping adsorption plate were obtained, which laid a foundation for the design of vacuum adsorption fixture. At the same time, the optimization design and modal analysis of the cutter head structure of leveling equipment are carried out. (4) the dynamic and static characteristic analysis of thick glue leveling equipment is carried out. The modal analysis of the equipment structure of the two schemes is carried out, the modes and frequencies of each order are given, and the advantages and disadvantages of the schemes are compared. The static analysis of the optimal equipment scheme is carried out, and the static deformation of the structure under the action of gravity and load is studied, which provides a reference and guidance for the fine design of the equipment structure. (5) the machining mechanism of thick glue leveling machine was analyzed and the simulation experiment of thick glue leveling was completed. Firstly, the cutting force model of flying cutter milling is constructed and its cutting force is calculated theoretically. Secondly, the relative motion trajectory equation of cutter tip is established, and the surface morphology of flying cutter cutting is preliminarily discussed. Finally, the simulation experiment of thick glue cutting is carried out on the existing high precision turn-milling compound machining center, and the influence of cutting tool, back feed rate, cutting speed and spindle speed on the surface quality of thick adhesive is explored. The cutting optimization parameters of thick adhesive are obtained.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN305.7

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