The Effect of Thermal Aging on Nano-Particle Removal

Abstract

The cleanness of the wafer backside is vital in improving process quality and device yield for advanced technology nodes, 10, 7 nm, and beyond [1,2]. Defects such as particles and scratches on the wafer backside could be sources of local deformation of a wafer [2], causing the photolithography hotspot generation [3], the local variation of film thickness, wafer breakage, so on. The micron-size particle defects are easily generated during deposition, etch, CMP processes, and they can be easily transferred to subsequent processing tools. The particles will be exposed to various process conditions such as high compressive stress and high temperature, and it can be seen on the end-effector and wafer chuck in the process chamber. In order to make the wafer backside clean, we need to understand the behavior of particle adhesion and removal, especially at high temperature. In this paper, the adhesion behavior of aged particles at high temperature and the footprint of them were studied.