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Fundamental Investigation into the Mechanism of Ultrasonic Wedge-Wedge Bonding through Change of Topography

通过形貌变化进行超声波楔-楔接合机理的基础研究

基本信息

批准号：
329797820
负责人：
Dr.-Ing. Jens Twiefel
金额：
--
依托单位：
Institut für Mikroproduktionstechnik (IMPT)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/329797820?language=en
关键词：
Fundamental Investigation into Mechanism Ultrasonic

项目摘要

Even since the ultrasonic wire bonding technique has been widely applied for more than half a century, the underlying mechanisms are still not completely understood, which prevents further improvement. The proposed project will be dedicated to investigate the unrevealed mechanisms as well as the influences of the bonding parameters on them. Specifically the friction and the softening phases are the focus points of the project. These phases play a significant role in oxides removal and microwelds formation and determine the bonding speed and strength.The oxide layer on the surface of wire or substrate is the main obstacle for the bonding formation. Both friction and softening phases affect the oxides removal process with regard to the detachment of oxides from pure metal surface and the transportation of the detached oxides. Due to the extremely tiny dimension, the natural oxide layer and the discretized oxides during the bonding process are hard to be observed, especially for real-time observation. In the proposed project, micro-particles and intransparent layers will be utilized for emulating the natural oxides. Through the step-wise and real-time observations, the removal paths of the oxides will be deduced. The substrate asperities provide locations for microwelds formation. The softening effect on these asperities, however, is unclear. In this project via structuring the substrate, the deformation of asperities at different locations will be analyzed so that the softening effect can be deduced. Furthermore, the microwelds area growth during the bonding process and the average strength of microwelds will be studied to obtain more information on the bonding strength.The oxide-metal contact regions, the metal-metal contact regions and microwelds regions are always changing within the bonding process. The complex dynamic bonding interface places an obstacle to the understanding of the bonding speed and strength. In order to real-time study the complex interface, a novel high resolution distributed sensor array will be developed and embedded in the substrate. By using this, the local tangential and normal forces at different locations of the interface will be measured. The output of the sensor array will provide large amount of information on the local changes, especially the local microwelds formation and breakage.Through the whole project, design of experiment (DOE) will be applied to analyze the influence of the process parameters. Finally, an empirical model will be established for predicting the changes at the interfaces over time, including the oxides distribution, the substrate roughness, the local strengths, and global strength. Based on the above analysis, new topographies on the substrate as well as on the wire will be proposed and evaluated so that a promotion of the bonding speed and quality will be gained. All of the results will provide a fundamental insight into the bonding mechanisms and close gaps in this field.

尽管超声波引线键合技术已广泛应用半个多世纪，但其基本机制仍未完全了解，这阻碍了进一步的改进。拟议的项目将致力于研究未揭示的机制以及键合参数对其的影响。具体来说，摩擦和软化阶段是该项目的重点。这些相在氧化物去除和微焊缝形成中起着重要作用，并决定着键合速度和强度。导线或基材表面的氧化层是键合形成的主要障碍。摩擦和软化阶段都会影响氧化物去除过程，即氧化物从纯金属表面的分离以及分离的氧化物的传输。由于尺寸极小，自然氧化层和键合过程中的离散氧化物很难被观察到，尤其是实时观察。在拟议的项目中，将利用微粒和不透明层来模拟自然氧化物。通过逐步、实时的观察，可以推导出氧化物的去除路径。基材的凹凸不平提供了形成微焊缝的位置。然而，对这些粗糙度的软化效果尚不清楚。在这个项目中，通过构造基材，将分析不同位置的凹凸变形，从而推断出软化效果。此外，还将研究键合过程中微焊缝面积的增长和微焊缝的平均强度，以获得有关键合强度的更多信息。氧化物-金属接触区域、金属-金属接触区域和微焊缝区域在键合过程中始终在变化。复杂的动态键合界面给键合速度和强度的理解带来了障碍。为了实时研究复杂界面，将开发一种新型高分辨率分布式传感器阵列并将其嵌入基板中。通过使用它，将测量界面不同位置处的局部切向力和法向力。传感器阵列的输出将提供有关局部变化的大量信息，特别是局部微焊缝的形成和破裂。在整个项目中，将应用实验设计（DOE）来分析工艺参数的影响。最后，将建立一个经验模型来预测界面随时间的变化，包括氧化物分布、基材粗糙度、局部强度和整体强度。基于上述分析，将提出并评估基板和导线上的新形貌，以提高键合速度和质量。所有结果都将为该领域的粘合机制和缩小差距提供基本的见解。