Design, fabrication, and characterization of an ultra-low cost inductively-coupled plasma chemical vapor deposition tool for micro- and nanofabrication

Abstract

The high cost of semiconductor fabrication equipment has traditionally represented a large barrier to entry for groups seeking to develop or commercialize novel micro- and nanoscale devices. Much of the cost barrier stems from the large size of the substrates processed in this equipment, and the associated complexity of maintaining consistent operation across the full substrate area. By scaling the substrate size down from the 150-300 mm diameter sizes commonly seen in today's production environments, the capital cost and physical footprint of tools for micro- and nanoscale fabrication can be dramatically decreased, while still retaining a similarly high level of performance. In this work, an ultra-low cost inductively-coupled plasma chemical vapor deposition (ICPCVD) system for processing substrates up to 50.8 mm (2") in diameter is presented. The ICPCVD system is built within a modular vacuum tool architecture that allows sections of the full tool to be easily and inexpensively replaced to adapt to new processing conditions or provide additional functionality. The system uses a non-pyrophoric mixture of silane (1.5% in helium) and low substrate temperatures ( : 150*C) to deposit uniform silicon-based films with a high quality comparable to films deposited in research-grade commercial tools. Using response surface methods, the performance of the ICP-CVD system has been characterized for both silicon dioxide and silicon nitride films, and repeatable control of the deposited film properties, including deposition rate, index of refraction, film stress, and density, has been demonstrated.