Characteristics of Pulse-Reverse Electrodeposited Cu Thin Film II. Effects of Organic Additives

Abstract

Pulse-reverse electrodeposition is capable of improving the superfilling ability and other properties of Cu in device interconnections. In this research, the influences of pulse-reverse electrodeposition on the properties of Cu thin film were investigated in the presence of organic additives used for Cu superfilling. The anodic step of pulse-reverse electrodeposition gave rise to changes in crystallinity, resistivity, grain size, and surface roughness. Minimum resistivity at the optimum dissolution ratio was observed, revealing a 14% reduction of the resistivity as compared to pulse electrodeposition samples. This was ascribed to the minimization of surface roughness produced by the selective dissolution of SPS-covered Cu as opposed to PEG-Cl--covered Cu. It was confirmed that the selectivity of the anodic step came from the adsorbates and the anodic potential, resulting in changes in the film properties. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.046209jes] All rights reserved.