Surface Modifications For Enhanced Performance On Psiloquest\u27S Application Specific Pads For Chemical Mechanical Planarization

We have recently studied, in detail, the \u27in-process\u27 degradation of polyurethane pads and the interactions of simulated copper slurries and segmented polyurethane in order to gain better understanding of the impact of consumables on CMP. Those studies clearly show that polyurethane, commonly used in the manufacture of CMP pads, is fundamentally incompatible with some of the chemicals used in copper CMP, such as hydrogen peroxide. The knowledge from those studies has been incorporated into the design and fabrication of a new class of application specific pads (ASP). Furthermore, we have leveraged our understanding of the chemical mechanisms and process kinetics to customize the surface of these new pads for specific applications. The application specificity is accomplished by matching the micromechanical properties of the pad surface to the material being removed during the CMP. The process advantages of the resultant ASP pads include: no need for the traditional pad \u27break-in\u27 before polish, no reconditioning / dressing ever, no need to keep pads wet in idle mode, long pad life, high selectivity, ergonomically friendly / easy pad changes and demonstrated pad-to-pad reproducibility. In this paper, we will examine the relationship between the pad surface characteristics and metal polishing of ASP pads