No abstract

As the feature size of the semiconductor device is becoming increasingly smaller and the transistor has become three-dimensional (e.g. Fin-FET structure), a simple Line Edge Roughness (LER) is no longer sufficient for characterizing these devices. Sidewall Roughness (SWR) is now the more proper metric for these metrology applications. However, current metrology technologies, such as SEM and OCD, provide limited information on the sidewall of such small structures. The subject of this study is the sidewall roughness measurement with a three-dimensional Atomic Force Microscopy (AFM) using tilted Z scanner. This 3D AFM is based on a decoupled XY and Z scanning configuration, in which the Z scanner can be intentionally tilted to the side. A sharp conical tip is typically used for imaging, which provides high resolution capability on both the flat surfaces (top and bottom) and the steep sidewalls.

As the critical design requirements decrease in modern day applications, we need to understand how confinement affects the performance of the materials we use to develop such applications. For example, the lubricant used on magnetic recording disks to reduce wear between the disk and head reader during unexpected intermittent contact is a good candidate to evaluate since this pertains to an application at the nanoscale. Lubricants used in hard drives need to have sufficient reflow and redistribution properties, which are stable in a wide range of temperatures experienced in today's hard drive applications. Since the materials properties of the confined system often differ from the bulk properties, tools to properly investigate these systems need to be developed and understood.In this study, we utilized atomic force microscopy (AFM) techniques to study the confinement effects and lubricant stability with temperature. Our studies have demonstrated distinct changes in adhesion force with changes in the thickness of the confining substrate layer. As adhesion is a component of friction, these changes in adhesion are directly related to lubricant performance and its ability to reduce wear between disk and reader with significant implications on device design considerations.