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工艺中使用的浆液包含几种化学添加剂，因此在某些条件下，浆中的颗粒可能会在抛光过程之前和期间凝聚并粘附在晶圆和/或垫板表面上。这样的聚集会导致缺陷，例如晶圆表面的刮擦。因此，对于良好的本地和全球平面性的表现而没有失败，确定准备稳定的浆液的最佳条件很重要。此外，在此过程中，正确获取了有关聚集体大小和形状的正确知识，即，在摇动和垫子之间，粒子的聚集和断裂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限制在两个平行壁之间的简单剪切流中的粒子动力学。我们开发了一个实验设备，具有共聚焦扫描激光显微镜，用于…对两个平行磁盘之间剪切流中粒子动力学的更高原位观察。在实验中，将直径为2μm的聚苯乙烯颗粒悬浮在NaCl水溶液中。我们可以观察到剪切流中聚集体的旋转行为。结果，发现较低的剪切速率会导致骨料尺寸较大。另外，随着两个磁盘之间的距离增加，聚集体的平均面积增加。我们在剪切流中构建了粒子聚集过程的数学模型。在此模型中，我们考虑了流体动力阻力，粒子与粒子之间的相互作用以及粒子和壁以及胶体相互作用。随着两个平行壁之间的距离增加，聚集体的大小增加，与墙接触的聚集体数量减少。当粒子与壁之间的胶体相互作用小于粒子和粒子之间的胶体相互作用时，聚集体的大小增加，与壁接触的聚集体数量减少。较少的