指纹模组制作工艺改进及效率提升研究

发布时间：2018-02-03 17:51

本文关键词： 指纹识别低温锡膏喷涂工艺焊盘设计可靠性　出处：《南昌航空大学》2017年硕士论文　论文类型：学位论文

【摘要】：指纹本身的唯一性和不变性,使得指纹识别技术在身份辨识系统中安全性能比传统上的基于密码的身份识别方式有了很大改进,越来越吸引企业和机构对其进行研究,目前也广泛被应用在民用产品中,如指纹锁、考勤机、手机和车载设备等。但是,由于指纹模组制作工艺较复杂,工艺冗长,设计上不成熟等问题的存在,研究如何改进指纹模组制作工艺及提升效率是指纹模组制作工艺的关键。本文就现有指纹模组制造工艺过程存在的表面刮伤、边缘积油等喷涂工序产品不良比例高、夹具种类繁多且上下料效率低、工艺流程繁琐、可靠性,组装间隙等方面问题,对模组制作工艺中使用到的锡膏性能和芯片焊盘结构设计以及组装工艺三方面进行分析并加以改进,在一定程度上改善了指纹模组的产品质量和制作效率,具体研究内容如下概述:(1)通过分析低温锡膏的性能,引入低温锡膏材料代替高温锡膏,实现了整版芯片先喷涂后焊接的可能,将原来需切割为单颗芯片后喷涂的方式改为直接整版芯片喷涂后切割,并对此改进了喷涂夹具的设计,该方式不仅简化了指纹识别模组制作工艺流程,而且解决了原有工艺的喷涂品质问题,并大大减少了喷涂工序中时间的消耗,显著的提升了制作效率,降低了喷涂夹具的使用数量。(2)由于低温锡膏相对原来工艺使用的高温锡膏,在焊接强度方面显得弱些,因而使用低温锡膏的产品可靠性方面可能存在很大的隐患。针对此问题,本文通过深入研究芯片焊盘的设计结构,进一步改进芯片焊盘结构设计,进而达到改善胶水的填充效果增强了焊接强度。并通过振动、落球和跌落等可靠性试验证实了优化后的焊盘结构设计能有效弥补低温锡膏焊接强度弱的缺陷,达到了所规定的相关可靠性标准。(3)针对指纹识别制作外观组装间隙不良问题,比如金属环和芯片间隙的存在。本文对此问题进行了研究,通过改变指纹制作工艺的部分流程,即让上盖金属环与芯片先组合再和FPC软板绑定,在一定程度上优化了间隙的问题。
[Abstract]:Due to the uniqueness and invariance of fingerprint, the security performance of fingerprint identification technology in identity identification system is much improved than that of traditional cipher based identification method. It attracts more and more enterprises and institutions to research, and is also widely used in civilian products, such as fingerprint locks, attendance machines, mobile phones and vehicle-mounted equipment. However, because of the fingerprint module manufacturing process is more complex. The process is long, the design is not mature and so on the existence of problems. How to improve the manufacturing process of fingerprint module and how to improve the efficiency is the key to the manufacturing process of fingerprint module. There are many problems in spraying process such as edge oil, such as bad proportion of products, various kinds of jigs and low efficiency of loading and unloading, complicated technological process, reliability, assembly clearance and so on. The properties of tin paste, chip pad structure design and assembly process were analyzed and improved. To some extent, the product quality and manufacturing efficiency of fingerprint module were improved. By analyzing the properties of low temperature tin paste and introducing low temperature tin paste instead of high temperature tin paste, the possibility of first spraying and welding the whole plate chip is realized. The original need to cut into a single chip after spraying instead of a direct chip after spraying cutting, and to improve the spray fixture design, this method not only simplifies the fingerprint identification module manufacturing process. Moreover, it solves the problem of spraying quality of the original process, and greatly reduces the consumption of time in the spraying process, and improves the production efficiency significantly. The quantity of spraying fixture is reduced. (2) because the low temperature tin paste is weaker than the high temperature tin paste used in the original process, the welding strength is weaker. Therefore, there may be great hidden trouble in the reliability of the products using low temperature tin paste. In view of this problem, this paper further improves the chip pad structure design through the in-depth study of chip pad design structure. Through reliability tests such as vibration, ball drop and drop, it is proved that the optimized pad structure design can effectively compensate the defects of low temperature solder paste welding strength. Meet the relevant reliability standard. 3) for fingerprint identification manufacturing appearance assembly gap problem, such as metal ring and chip gap exists. This paper studies this problem. By changing part of the process of fingerprint fabrication, that is, the metal ring of the upper cover is combined with the chip first and then bound to the FPC soft plate, the gap problem is optimized to a certain extent.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41

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