Challenges and Mechanisms of CMP Slurries for 32nm and Beyond

CMP slurries for 32nm and beyond are required to effectively planarize surfaces with fine and delicate device patterns without causing any nanodefects, without contributing nanocontaminants, and without generating atomic-level-roughness. Key solutions to these challenges are material removal using homogeneous and efficient mechanical action, surface protection using appropriate additives, and thorough contamination control (from large particles to dissolved gasses and light). The important parameter for mechanical action with abrasives is friction energy. Key factors to increase friction energy are: i) the number of active particles, ii) the contact area of each particle, and iii) the friction coefficient of each particle. These factors can be controlled with size, shape, morphology or surface charge of abrasive particles. Controlling abrasive shape and surface charge are especially important to achieve higher removal rate.