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

本工作的目的是研制一种微型压缩试验机，用于测量在剪切流动中形成的颗粒集料的力学性能，并研究几种因素对集料压缩变形特性的影响。1.玻璃纤维探头的制作：通过氢氟酸刻蚀和光学抛光相结合的方法，建立了一种压缩颗粒集料的玻璃纤维探头的制造工艺。2.颗粒集料压缩变形行为的可视化：建立了叠加激光扫描共聚焦显微镜图像的集料三维可视化技术。3.压缩试验：对剪切流动中形成的颗粒集料进行了压缩试验，验证了研制的微型压缩试验机的有效性。在压缩试验之前，利用激光扫描共聚焦显微镜原位观测装置，研究了平行平板间剪切流中胶乳粒子的聚集和破碎行为。结果表明，随着剪切速率的增加，骨料的平均尺寸减小，由于流体动力作用，骨料的缝隙宽度减小。随着缝隙宽度的减小，聚集体的尺寸分布变窄。此外，团聚体的分维(即团聚体的结构)几乎与剪切速率和间隙宽度无关，约为1.2，这表明团聚体相对致密。

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.