Using Ionizers to Reduce Electrostatically Adhered Particles on Wafer Backside

Abstract

We present results and discussion on the positive impact of ionizer(s) used in multiple configurations on wafer backside and front-side particle adders in physical vapor deposition (PVD) processing tools. We provide a hypothesis, followed by testing, that establishes a relationship between electrical surface charge collection data and particle data obtained in a laboratory setting as well as a real-world wafer fabrication facility environment. For chip manufacturers, controlling surface charges on production wafers results in a reduced number of undesirable particles, thereby resulting in higher yield, more reliable final product chips, and reduced product losses. And for equipment manufacturers, more reliable and better tool performance can lead to increased productivity. The INOVA PVD system's good particle performance, as demonstrated on good quality wafers, is made marginal quality wafersmore robust with an ionizer installation when marginal quality wafers are used.