A Silicon Oxide Antireflective Layer For Optical Lithography Using Electron Cyclotron Resonance Plasma Deposition

Abstract

Using electron cyclotron resonance plasma deposition, we have developed an SiOx film as an antireflective layer (ARL) for the gate process of LSI fabrication by i-line and KrF lithography. The ARL is an absorption type and is 100 nm thick. The estimated optimum optical properties of the ARL for i-line were n=2.3–2.6 and k=0.5–0.6. For KrF, they were n=1.8–2.1 and k=0.5–0.6. An SiOx film having these properties can be reproducibly deposited at SiH4/O2 gas flow rate ratio of 1.3 for i-line and 1.1 for KrF. The chemical compositions of the films are SiO0.5 for i-line and SiO1.0 for KrF. The SiO0.5 film was used as an i-line ARL for 0.35-µ m LSI gate fabrication and superior process performance and sufficient critical dimension controllability (variation within 19 nm of 3σ) were obtained.