Feng Q. Liu

Cu Planarization in Electrochemical Mechanical Planarization

The electrochemical mechanical planarization (Ecmp) process is a revolutionary planarization technology uniquely combining removal rate controlled by charge with superior planarization efficiency in the near no-shear regime. A planarization mechanism for Ecmp is proposed to explain the high planarization efficiency. Meanwhile, the effects of applied voltage on removal rate and planarization efficiency are discussed. The electrical feature allows Ecmp to be a planarization process with removal rate independent of downforce, enabling a wide removal rate window and high planarization efficiency.

A low cost and residue-free abrasive-free copper CMP process with low dishing, erosion and oxide loss

Traditional slurry copper (Cu) CMP processes have disadvantages in terms of dishing, erosion, Cu and oxide losses, micro-scratches and cost due in part to the presence of abrasive particles during polishing. A stable abrasive-free (AF) Cu CMP process and a low-abrasive barrier removal process have been developed. With these processes it has been possible to repeatably demonstrate metal-residue free wafers with low dishing, low erosion, low metal and oxide losses, over-polishing insensitivity, and low cost.