微电子封装切割熔锡失效分析及对策

熔锡是微电子封装QFN(Quad Flat No-leads Package,方形扁平无引脚封装)产品在切割生产过程中的核心质量不良,是导致产品可焊性失效的关键风险点。本文针对QFN封装产品的切割生产过程进行熔锡失效的原因分析和对策探讨。     

简单类COG产品电显异常的一种成因分析

通过严格的失效分析步骤,借助于切片分析手段,找到了IC的一种设计或制造缺陷。原因是IC切割线外的测试焊盘在切割不良时会有毛刺,毛刺在COG邦定过程中通过ACF的导电粒子与ITO电极发生了短路,从而导致显示异常。     

二维固态有源相控阵失效单元补偿新方法

提出二维固态有源相控阵失效单元补偿的新方法，该方法基于失效单元矩形切割和线性规划方法。可适用于有源阵列多单元任意失效分布的实时补偿。在保证失效补偿后两主平面副瓣性能完全恢复的情况下，用线性规划方法对空间平均融瓣进行了优化。由于采用实数算法，仅需对非失效单元的幅度进行调整。理论分析及模拟计算表明该方法在工程应用中是切实可行的。     

利用激光回波实时检测切割质量

介绍激光切割的特点,分析激光切割过程中的激光回波特性与切割中穿透现象的关系,并把这种关系与控制系统相结合,提出了一种穿透检测的实时监控途径,为进一步完善切割过程的实时监控奠定基础.     

PCB的腐蚀失效及其分析

通过一个电子辞典用PCB腐蚀失效的分析案例,介绍了PCB的失效现象、分析过程和分析技术．阐述了其失效机理,并提出了相应的改进措施。     

CO2激光切割电子强化玻璃过程的有限元模拟与实验

在激光热裂法切割玻璃的过程中,温度起着至关重要的作用。为了准确掌握切割过程中温度场的分布,提高切割质量,提出了一种CO2激光切割玻璃基板的数值模拟方法。在ANSYS有限元环境下,建立了激光热应力切割电子强化玻璃的三维有限元分析模型,对温度场进行了分析。通过实验验证,得到了切割过程中温度场在不同参数下的变化及其对切割质量的影响以及温度分布与激光功率、光斑尺寸和扫描速度的非线性关系。     

半导体材料切割过程中的几点静力学特性

本文从半导体材料切割过程中刀具刃口的受力特性出发，建立了力学模型，推导出了切片外形特性方程。分析了切割过程中刃口的运行轨迹及加速度曲线。文中结论对于综合控制切片TTV值及切片微观质量具有指导意义。同时，根据切割过程中的本质关系提出了切割设备及其自动跟踪校正系统的发展方向。     

半导体材料切割过程中的几点静力学特性

本文从半导体材料切割过程中刀具刃口的受力特性出发，建立了力学模型，推导出了切片外形特性方程。分析了切割过程中刃口的运行轨迹及加速度曲线。文中结论对于综合控制切片TTV值及切片微观质量具有指导意义。同时，根据切割过程中的本质关系提出了切割设备及其自动跟踪校正系统的发展方向。     

航天产品长期贮存失效分析研究

本文介绍了导弹产品贮存过程中性能变化的主要影响因素,分析了典型产品在长期贮存过程中的失效模式、失效机理、失效影响等内容,并针对这些问题提出了一些建议,以供参考.     

电磁脉冲应力下MOS器件退化失效建模

通过分析电磁脉冲应力下,栅氧化层软击穿(MOS器件主要失效模式)的失效机理,得出结论:它符合基于随机过程的退化失效模型。根据此结论,提出利用该模型来描述电磁脉冲应力下MOS器件的退化失效过程,并给出相应的退化失效模型。同时针对退化失效模型中的失效阈值问题,研究了随机失效阈值问题,分析了周期电磁脉冲应力下MOS器件的失效阈值问题,给出动态应力-强度干涉(SS)I模型。这些为更合理描述和分析MOS器件的退化失效问题提供了新的途径。     

Prediction of sawing force for single-crystal silicon carbide with fixed abrasive diamond wire saw

Fixed abrasive diamond wire saw has been used to cut hard-and-brittle materials into wafers, such as silicon carbide. The force of a single abrasive determines the cutting depth, and affects material removal mode and crack propagation length. Therefore, the sawing force is a key factor that affects the surface/subsurface quality of wafers. In this paper, a numerical sawing force predicting method considering wire saw parameters was proposed with the combination of both ductile removal and brittle fracture removal for each single abrasive. A new calculation method of single abrasive cutting force considering frictional force component and new material removal way considering the effect of lateral crack were adopted. Then the influences of process parameters and wire parameters on sawing force were analyzed. Finally, mathematical sawing force formulas described by both process parameters and wire saw parameters were obtained using the new sawing force prediction method. The validity of this prediction method and sawing force formulas was verified through experiments in the literature under the same process parameters and wire saw parameters.     

半导体晶体线锯切割工艺研究

线锯切割技术在半导体晶体切割领域已经得到了广泛应用。对传统内圆切割技术进行了介绍,并针对新兴线锯切割技术的现有分类和研究水平做了总结,阐述了自由磨料线锯切割和固结磨料线锯切割两大类别的工作原理和研究进展。自由磨料线锯切割是取代内圆切割的一种广泛技术,而固结磨料线锯切割则是针对高切割效率要求的重要改进。针对晶体线锯切割技术所做的综述,有助于研究者了解前沿研究进展,把握晶体线锯切割的发展方向。     

Mechanisms of wafer sawing and impact on wafer properties

Silicon wafer wire‐sawing experiments were realized with different sets of sawing parameters, and the thickness, roughness, and cracks depth of the wafers were measured. The results are discussed in relation to assumptions underlying the rolling–indenting model, which describes the process. It was also found that the silicon surface at the bottom of the sawing groove is different from the wafer surface, implying different sawing conditions in the two positions. Furthermore, the measured parameters were found to vary along the wire direction, between the entrance of the wire in the ingot and its exit. Based on these observations, some improvements for the wire‐sawing model are discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

高温存储下铜线键合焊点分析

采用铜引线键合工艺生产的电子元器件在服役中会产生热,引起引线与金属化焊盘界面出现IMC(intermetallic compound,金属间化合物)。IMC的生长和分布将影响键合点的可靠性,严重时会出现"脱键",导致元器件失效。研究了焊点在服役过程中的演化,选取铜线键合产品SOT-23为试验样品,分析了在高温存储试验环境下焊点键合界面IMC的生长及微观结构变化情况。     

中小功率CO2激光的厚板切割技术

分析了激光厚板切割技术的能量平衡和技术难点,具体介绍了几种厚板切割新技术,包括预热法、散焦法、激光锯切法、双聚焦法.并从工艺角度分析了几种切割技术的优缺点.     

Subsurface crack damage in silicon wafers induced by resin bonded diamond wire sawing

In order to optimize the process of wire sawing, this work studied the subsurface crack damage in silicon wafers induced by resin bonded diamond wire sawing using theoretical and experimental methods. A novel mathematical relationship between subsurface crack damage depth and processing parameters was established according to the indentation fracture mechanics. Sawing experiment using resin bonded diamond wire saw was performed on a wire saw machine. The validity of the proposed model was conducted by comparing with the experimental results. At last, the influences of processing parameters on subsurface damage depth were discussed. Results indicate that the median cracks are mainly oblique cracks which generate the subsurface crack damage. On the diamond wire saw cross section, the abrasives with the position angle 78° between abrasive position and vertical direction generate the largest subsurface damage depth. Furthermore, abrasives, generating the subsurface damage, tend away from the bottom of diamond wire with the increase of wire speed or decreases with the increase of feed rate. However, the wire speed and feed rate have opposite effects on the subsurface crack damage depth. In addition, the subsurface crack damage depth is unchanged when the ratio of feed rate and wire speed does not change.     

薄片划片微损伤与芯片断裂强度探讨

超薄圆片的减薄、划片技术是集成电路封装小型化的关键基础工艺技术,随着减薄后化学机械抛光（CMP）、旋转腐蚀、干法刻蚀或干法抛光等释放应力技术被广泛采用,减薄造成的圆片背面损伤几乎为零,所以划片造成的微损伤对芯片断裂强度的影响变得越来越突出。本文分析了影响芯片断裂强度的主要原因,对薄片划片微损伤的来源、危害及解决方法进行了探讨。同时,着重介绍了一种新的激光划片方式,即喷水波导激光（LMJ）划片法。     

线锯钢线断线续切技术研究

根据切割线的特性,分析了在多线切割过程中铜丝断线的各种原因;在生产中,有效控制断线率可以对降本增收起到很大的作用。在大量实验的基础上,归纳总结出断线后续切技术,有效的保障了生产工作的顺利进行。     

机线张力数控系统卷绕驱动设计

简述了力矩电机的原理,分析机线张力数控系统卷绕驱动机构的工艺要求,针对普通伺服电机驱动收线轮装置存在的缺陷,提出了用力矩电机控制收线轮的方案。在卷绕驱动机构设计参数确定过程中,阐述了切割线张力形成的原理,并且依据控制电机的选择原则,给出了力矩电机选择计算方法,最终完成了力矩电机控制方式的设计,实现了多线切割恒张力、恒限速度的要求。采用力矩电机驱动收线轮能够使卷绕机构满足系统要求,简化卷绕装置的结构,并能使切割过程运行平稳。     

Experiment study on electroplated diamond wire saw slicing single-crystal silicon

This paper conducted the slicing experiments of single-crystal silicon using a reciprocating electroplated diamond wire saw. The machined wafer topography and wire wear were observed by using scanning electron microscope (SEM). The influences of process parameters and cutting fluids on single-crystal silicon wafer surface roughness (SR), subsurface micro-crack damage (SSD) depth, total thickness variation (TTV) and warp were investigated. The bonded interface sectioning technique was used to examine the cut wafers SSD depth. Study results show that a higher wire speed and lower ingot feed speed can produce lower wafer SR and SSD; the lower warp of wafer needs lower wire speed and ingot feed speed; and low wafer TTV can be obtained by an appropriate matching relationship between wire speed and ingot feed speed. The synthetic cutting fluid has a better total effect to improve the wafer quality. The pulled-out of diamond abrasives is the main wear form of wire, which indicates that more research on improving the abrasives retaining strength on wire surface should be investigated in fixed-abrasive wire manufacturing process, in order to improve the wire life and wire saw machining process.