The Nearest Uniformity Producing Profile (NUPP): A Generalized Optimization Criterion for Thin-Film Processing Applications

University Of Maryland, College Park, College Park MD

Investigators

Abstract

ABSTRACT PI: Raymond A. Adomaitis and Gary W. Rubloff Institution: University of Maryland Proposal Number: 0554045 Title: The Nearest Uniformity Producing Profile (NUPP): A Generalized Optimization Criterion for Thin-Film Processing Applications The development of a new criterion for spatial uniformity control in thin film deposition processes (e.g., chemical vapor deposition for semiconductor manufacturing) is planned, applicable to any film quality (thickness, composition, microstructure, and electrical properties, among others) for all deposition systems where the substrate is rotated to improve uniformity. The approach is based on identifying the subspace of all deposition profiles on the stationary substrate (e.g., stalled wafer) that produce uniform films under rotation and then projecting a deposition profile to be controlled onto a sequence of uniformity-producing basis functions spanning that subspace to determine the Nearest Uniformity Producing Profile (NUPP). This mathematical criterion depends only on the geometrical characteristics of the deposition system, and control and optimization methods can be developed to reduce the deviation from the NUPP giving a universally applicable film control methodology. An important contribution of the NUPP concept and underlying theory is that the latter reveals new structure in the uniformity and nonuniformity producing subspaces, providing insight into thin-film process design and control principles and an opportunity to unify these principles across a range of reactor designs. Intellectual Merit The research would develop a completely new approach to the control of thin film processing and demonstrate its effectiveness in an industrial setting. Preliminary research on the development of this new analysis and control technique has revealed open issues in terms of the mathematical and computational aspects of the framework, and the long standing relationship of the PI with the industrial partner creates an ideal situation for testing this control approach. Broader Impact A unique aspect of the uniformity control technique is that it is based on a minimal number of physical assumptions, resulting in a technique applicable to any uniformity criterion in a wide range of thin film processing control, optimization, and design applications, including all CVD, etch, PVD (physical vapor deposition), atomic layer deposition (ALD), and any other thin film process with a rotating substrate, giving the technique very broad industrial impact. Thin film processing in semiconductor, optoelectronic, optical coatings, and other industries will benefit from this approach. The majority of funding will be dedicated to providing undergraduate and graduate research opportunities in a state-of-the-art industrial research and production facility; the computational tools to be developed will be ideally suited for packaging and broad distribution in the format of a MATLAB toolbox and an associated short course.