Digital chemical vapor deposition and etching technologies for semiconductor processing

A novel concept on digital chemical vapor deposition (CVD) and etching technologies is described. ArF excimer laser irradiation to a condensed Si2H6 layer on a substrate cooled to −70 °C has resulted in spatially selective poly-Si film growth. The adsorbate thickness control by gas pressure and substrate temperature allows shot by shot atomic layer growth of Si. Digital CVD of SiO2 is also achieved by a repetitive cycles of silane radical deposition and subsequent oxidation. This reaction is promoted by an alternate introduction of pulsed microwave-discharged SiH4 and O2 beams. The deposition species ejected with supersonic velocity into the high vacuum reactor fills SiO2 into a deep trench. Also, digital etching of Si monolayers has been studied for the goal of damage-free etching. A preliminary result obtained by repeating the reaction cycle consisting of adsorption of fluorine atoms on a Si surface cooled to −100 °C and subsequent Ar+ ion irradiation has realized atomic layer etching of Si(100).