Fundamental and Technological Aspects of Finishing Balls of Advanced Ceramics, Glasses, and Silicon Using Magnetic Field Assisted Polishing

本计画系利用磁浮抛光技术，对高级陶瓷、玻璃、半导体材料之球体进行抛光。 通过研磨、抛光、精研对高级陶瓷和玻璃进行的常规精加工通常会导致若干缺陷，包括大划痕、由于颗粒移位而形成的凹坑、玻璃情况下玻璃相的粘性流动以及表面和表面下的微裂纹。 这些缺陷影响这些材料的性质和性能，并且传统上通过随后的金刚石抛光去除。为了解决这一难题，开发了一种称为磁浮抛光的“温和”抛光技术（在NSF支持的最近完成的调查中），而无需使用金刚石磨料。 在Si 3 N4球上完成了4 nm Ra和40 nm Rmax数量级的表面光洁度，球度在0.25微米的范围内，总抛光时间为~ 20小时。 一个更好的理解的机械和化学机械的行动参与Si 3 N4球的抛光。在这个项目中，研究人员打算将这项工作推广到其他先进陶瓷（每批不同大小和数量的球），各种玻璃和硅。 高级陶瓷，例如Si 3 N4、SiC、ZrO 2和Al 2 O3正越来越多地被考虑用于结构应用，其中Si 3 N4，特别地，被选择用于混合球和滚子轴承应用。 类似地，各种类型的玻璃用于光学应用，例如透镜，最近正在考虑将球形硅球用于微电子应用（而不是硅晶片）。 这项研究将是第一次对硅球（而不是晶圆）的抛光磁浮。因此，所提出的精加工技术预计将解决结构、光学和电子应用，这些应用可能对各种先进技术应用的球的制造产生重大影响。

This project is on the finishing of balls of advanced ceramics, glasses, and semiconductor material using the magnetic float polishing technology. Conventional finishing of advanced ceramics and glasses by grinding, polishing, lapping generally leads to several defects including large scratches, formation of pits due to the dislodgment of grains, viscous flow of the glassy phase in the case of glass, and surface and subsurface microcracks. These defects affect the properties and performance of these materials and are traditionally removed by subsequent diamond polishing. To address this difficult problem, a "gentle" finishing technology, called the magnetic float polishing was developed (in a recently completed investigation supported by NSF) without the need to use diamond abrasives. Surface finish on the order of 4 nm Ra and 40 nm Rmax with sphericity in the range of 0.25 micrometers were accomplished on Si3N4 balls with a total polishing time of ~ 20 hours. A better understanding of the mechanical and chemo-mechanical actions involved in the polishing of Si3N4 balls has resulted. In this project, the investigators intend to generalize this work to cover other advanced ceramics (balls of different size and number per batch), various glasses, and silicon. Advanced ceramics, such as Si3N4, SiC, Zr02, and Al2O3 are increasing being considered for structural applications of which Si3N4, in specific, is chosen for hybrid ball and roller bearing applications. Similarly, various types of glasses are used for optical applications, such as lenses and recently spherical silicon balls are being considered for micro-electronic applications (instead of silicon wafers). This research would be the first of its kind on the finishing of silicon balls (instead of wafers) by magnetic float polishing. Thus, the finishing technology proposed is expected to address structural, optical, and electronic applications that can have a significant impact on the manufacture of balls for various advanced technology applications.