Study on the influence of hardmask morphology on substrate profile in plasma etching process

In plasma etching process, hardmask is an important protective material for substrates, especially for deep silicon etching. The consumption and deformation of hardmask affect the substrate etching profiles, which can severely impact the devices performance. The scaling of devices and more complex structures demand for higher performance of hardmask. However, it is difficult and costly to characterize the evolution of hardmask profile during etching. Modeling is an effective manner to overcome this challenge. In this paper, we take the Si etching by SF₆/O₂ mix gas as the modeling target and conduct theoretic study, using the commercial simulation software named PEGASUS. We explored the effects of different hardmask parameters including thickness, open CD and sidewall angle on substrate etching profile, and characterize the etching rate, sidewall angles, and profile defects such as bowing. This study seeks to provide insight into the correlation, between hardmask morphology and etching profile, and provides theoretical support for the stack structure design and