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).