A novel technology to reduce the antenna charging effects during polysilicon gate electron-cyclotron-resonance etching

Abstract

A novel technique, which uses Cl-2/O-2 mixed gas in the electron cyclotron resonance (ECR) etching system, has been proposed to remove the antenna charging effect of the MOS capacitors with 5-nm-thick oxides during polysilicon gate etching. The Cl-2/O-2 can cause the trenching effect and prevents the gate oxide from the charging damage. Furthermore, the ECR system can provide high polysilicon/oxide selectivity so that the Si substrate under gate oxide is not directly bombarded by the ions. Consequently, the E(bd) degradation of the MOS capacitors disappears as the trenching effect is apparent by using moderate Cl-2/O-2 mixed gas.