Study on compressive and shear deformations of an abrasive particle aggregate in chemical mechanical polishing process

本工作的目的是制造一个微型压缩测试仪，以测量在剪切流中形成的颗粒聚集体的力学性能，并研究几个因素对聚集体的压缩变形特性的影响。1.玻璃纤维探针的制造：通过氢氟酸蚀刻和光学抛光的组合，确立了用于压缩颗粒集合体的玻璃纤维探针的制造技术。2.颗粒集合体的压缩变形行为的可视化：建立了集料的激光扫描共聚焦显微镜图像叠加三维可视化技术。3.压缩试验：对剪切流场中形成的颗粒聚集体进行了压缩实验，并利用激光扫描共聚焦显微镜对剪切流场中胶乳颗粒的聚集和破碎行为进行了原位观察，验证了自行研制的微型压缩实验装置的有效性。结果，聚集体的平均尺寸随着剪切速率的增加而减小，并且由于作用于聚集体的流体动力学效应，差距宽度减小。随着差距宽度的减小，团聚体的粒径分布变窄。此外，分形维数，即，聚集体的结构几乎与剪切速率和差距宽度无关，约为1.2，这表明聚集体相对致密。

The aims of the present work are to manufacture a micro compression tester to measure the mechanical properties of a particle aggregate formed in a shear flow, and to investigate the effect of several factors on the compressive deformation characteristics of the aggregate. This year, the followings were carried out.1.Manufacture of glass fiber probe : a manufacturing technique of a glass fiber probe to compress a particle aggregate was established by combining hydrofluoric acid etching and optical polishing.2.Visualization of compressive deformation behavior of particle aggregate : a three-dimensional visualization technique of aggregate by superimposing laser scanning confocal microscope images was established.3.Compression test : the compression test of a particle aggregate formed in a shear flow was carried out, and the effectiveness of a micro compression tester developed here was demonstrated.Before the compression test, the aggregation and breakup behaviors of latex particles in shear flow confined between two parallel plates were investigated using an in situ observation apparatus with a laser scanning confocal microscope. As a result, the average size of the aggregates decreases as shear rate increases and the gap width decreases due to the hydrodynamic effect acting on the aggregates. The size distributions of the aggregates become narrow as the gap width decreases. In addition, the fractal dimension, i.e., the structure of the aggregates, was almost independent of shear rate and the gap width, and approximately 1.2, which suggests that the aggregates are relatively compact.