A NOVEL TECHNOLOGY TO REDUCE THE ANTENNA CHARGING EFFECTS DURING POLYSILICON GATE ELECTRON-CYCLOTRON-RESONANCE ETCHING

A novel technique, which uses Cl-2/O-2 mixed gas in the electron cyclo tron resonance (ECR) etching system, has been proposed to remove the a ntenna charging effect of the MOS capacitors with 5-nm-thick oxides du ring polysilicon gate etching. The Cl-2/O-2 can cause the trenching ef fect and prevents the gate oxide from the charging damage. Furthermore , the ECR system can provide high polysilicon/oxide selectivity so tha t the Si substrate under gate oxide is not directly bombarded by the i ons. Consequently, the E(bd) degradation of the MOS capacitors disappe ars as the trenching effect is apparent by using moderate Cl-2/O-2 mix ed gas.