Mechatronic Spatial Atomic Layer Deposition for Closed-Loop and Customizable Process Control

Abstract

A customized atmospheric-pressure spatial atomic layer deposition (AP-SALD) system is designed and implemented, which enables mechatronic control of key process parameters, including gap size and parallel alignment. A showerhead depositor delivers precursors to the substrate while linear actuators and capacitance probe sensors actively maintain gap size and parallel alignment through multiple-axis tilt and closed-loop feedback control. Digital control of geometric process variables with active monitoring is facilitated with a custom software control package and user interface. AP-SALD of TiO2 is performed to validate self-limiting deposition with the system. A novel multi-axis printing methodology is introduced using x-y position control to define a customized motion path, which enables an improvement in the thickness uniformity by reducing variations from 8% to 2%. In the future, this mechatronic system will enable experimental tuning of parameters that can inform multi-physics modeling to gain a deeper understanding of AP-SALD process tolerances, enabling new pathways for non-traditional SALD processing that can push the technology towards large-scale manufacturing.