Void free and low stress shallow trench isolation technology using P-SOG for sub 0.1 /spl mu/m device

Abstract

Highly reliable void free shallow trench isolation (VF-STI) technology by employing polysilazane based inorganic spin-on-glass (P-SOG) is developed for sub-0.1 /spl mu/m devices. In order to overcome the difficulties from the gap-filling and accumulated mechanical stress in STI, a P-SOG pillar is introduced at the trench bottom. As a result, the P-SOG pillar, having low stress, improves data retention time and hot carrier immunity in 256 Mbit DRAM by reducing cumulative STI stress. In addition, VF-STI shows an excellent extendibility in terms of gap filling capability even at an aspect ratio of more than 10 without void formation.