Mechanism Analysis of Plasma Charging Damage on Gate Oxide for HDP FSG Process

Abstract

For its stability and relatively lower K value, FSG (fluorine silica glass) is widely used in 0.18μm and below VLSI process. In this paper, the plasma charging damage on 30Aå gate oxide from the high-density-plasma deposition (HDP) of FSG is investigated. Positive and negative nondestructive JTDDB stress is applied to fresh transistors to simulate the plasma charging current. According to the results comparison, positive plasma stress at the end of the HDP-CVD FSG deposition is found to be the major cause of damage. The damage is located near the Gate/SiO2 interface. By increasing the FSG thickness, the damage is effectively suppressed.