Run‐to‐run control of PECVD systems: Application to a multiscale three‐dimensional CFD model of silicon thin film deposition

Abstract

Deposition of amorphous silicon thin films via plasma‐enhanced chemical vapor deposition (PECVD) and batch‐to‐batch operation under run‐to‐run control of the associated chambered reactor are presented in this work using a recently developed multiscale, three‐dimensional in space, computational fluid dynamics model. Macroscopic reactor scale behaviors are linked to the microscopic growth of amorphous silicon thin films using a dynamic boundary which is updated at each time step of the transient in‐batch simulations. This novel workflow is distributed across 64 parallel computation nodes in order to reduce the significant computational demands of batch‐to‐batch operation and to allow for the application and evaluation in both radial and azimuthal directions across the wafer of a benchmark, run‐to‐run based control strategy. Using 10 successive batch deposition cycles, the exponentially weighted moving average algorithm, an industrial standard, is demonstrated to drive all wafer regions to within 1% of the desired thickness set‐point in both radial and azimuthal directions across the wafer surface. This is the first demonstration of run‐to‐run control in reducing azimuthal film nonuniformity. Additionally, thin film uniformity is shown to be improved for poorly optimized PECVD geometries by manipulating the substrate temperature alone, without the need for re‐tooling of the equipment. © 2018 American Institute of Chemical Engineers AIChE J, 65: e16400 2019