Width Walk Control in 3D NAND Staircase Structure Etching

As the number of 3D NAND layers rises, the need to precisely control the lateral shift, called width walk, during the staircase etching process becomes crucial. In this study, we reveal that the width walk of staircase formation is controllable by three specific tuning parameters in the etching recipe. The improved control of the width walk reduces the shift of 4.9 nm per ON layer etching to 0.81n...