As the manufacturing processes for Dynamic Random-Access Memory (DRAM) continue to miniaturize, gaining precise control over the etching profile of active area (AA) fin structures has emerged as a pivotal challenge in enhancing production yields. Within the industry, the "wiggling AA effect" has been widely noted. This phenomenon is marked by irregular sidewalls and curved distortions in the fin structures, leading to a notable decline in capacitance efficiency and overall device reliability. For a considerable time, the underlying physical causes of this effect have remained elusive. The absence of systematic characterization and mechanistic models has further complicated efforts to achieve precise control over the etching process.

To tackle these challenges head-on, a research team from the Institute of Microelectronics at the Chinese Academy of Sciences has taken an innovative approach. They have seamlessly integrated Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) 3D reconstruction technology with etching process models. By conducting simulations and experiments across a range of process conditions, the team has successfully uncovered the core mechanisms driving the wiggling AA effect and developed effective control strategies to mitigate it.