A Study on the Gap-Fill Process Deposited by the Deposition/Etch/Deposition Method in the Space-Divided PE-ALD System

Abstract

This study concerns the development of a gap-fill process technology for isolating trench patterns. There are various gap-filling techniques in the case of trench patterns; nevertheless, a processing technology adopting the DED (deposition/etch/deposition) method was developed in this study. After the etch step, an Ar/O2 (1:2) plasma treatment technology reduced the residual amount of F in the films to 0.05%. By improving the etch uniformity, the deposition uniformity after the DED process on a 12-inch flat wafer was secured within <1%, and a high-quality SiO2 thin film with a dielectric constant of 3.97 and a breakdown field of 11.41 MV/cm was fabricated. The DED method can be used for gap-filling even in patterns with a high aspect ratio by changing process parameters, such as RF power and division of etch steps, according to the shape, depth, and CD size of the pattern. This study confirmed that a void-free gap-fill process can be developed in a trench pattern with a maximum aspect ratio of 40:1.