Experimental and Theoretical Studies on Particle Dynamics in Chemical Mechanical Polishing (CMP) Process

化学机械抛光 (CMP) 过程中颗粒动力学的实验和理论研究

基本信息

批准号：
11450288
负责人：
HOZAWA Mitsunori
金额：
$ 6.78万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

Since the slurries used in the CMP process contain several chemical additives, under certain conditions, the particles in the slurries may aggregate and adhere to the wafer and/or pad surfaces before and during the polishing process. Such aggregations result in defects such as scratches on the wafer surface. Therefore, for performance of good local and global planarity without failures, it is important to determine the optimal conditions for preparation of stabilized slurries without aggregations. In addition, the acquirement of correct knowledge about the size and shape of aggregates during the process, i.e., the aggregation and breakage behaviors of particles in a confined shear flow between the wafer and the pad, is also a critical issue. The aim of the present work is to investigate experimentally and theoretically the particle dynamics in a simple shear flow confined between the two parallel walls.We developed an experimental apparatus with a confocal scanning laser microscope for … More in-situ observation of the particle dynamics in a shear flow between two parallel disks. In experiment, polystyrene particles of 2μm in diameter were suspended in a NaCl aqueous solution. We could observed the rotational behavior of aggregates in a shear flow. As a result, it was found that lower shear rate results in larger size of aggregates. In addition, as the distance between two disks increased, the average area of aggregates increased.We constructed a mathematical model for particle aggregation process in a shear flow. In this model, we considered the hydrodynamic drag, the interaction between particle and particle, and particle and wall, and colloidal interactions. As the distance between two parallel walls increased, the size of aggregates increased and the number of aggregates contacted with wall decreased. When the colloidal interaction between particle and wall was smaller than that between particle and particle, the size of aggregates increased and the number of aggregates contacted with wall decreased. Less

由于CMP工艺中使用的浆料含有多种化学添加剂，在某些条件下，浆料中的颗粒可能在抛光工艺之前和期间聚集并粘附到晶片和/或抛光垫表面上，这种聚集导致诸如划痕之类的缺陷。因此，为了获得良好的局部和整体平坦性而不会出现故障，确定制备稳定浆料而不会聚集的最佳条件非常重要。此外，获得有关尺寸和形状的正确知识也很重要。在此过程中的聚集体，即晶片和垫之间的有限剪切流中颗粒的聚集和破碎行为，也是一个关键问题。本工作的目的是从实验和理论上研究颗粒动力学。限制在两个平行壁之间的简单剪切流。我们开发了一种带有共焦扫描激光显微镜的实验装置，用于对两个平行盘之间的剪切流中的颗粒动力学进行原位观察。将直径为 2μm 的颗粒悬浮在 NaCl 水溶液中，我们可以观察到聚集体在剪切流中的旋转行为，结果发现，较低的剪切速率会导致聚集体的尺寸增大。两个圆盘增加，聚集体的平均面积增加。我们构建了剪切流中颗粒聚集过程的数学模型，在该模型中，我们考虑了流体阻力、颗粒与颗粒之间、颗粒与壁之间的相互作用，并且随着两个平行壁之间的距离增加，聚集体的尺寸增大，与壁接触的聚集体的数量减少。与墙体接触的骨料数量减少。