In-situ Process Control for Semiconductor Manufacturing

There is a critical need for exact, real-time reaction control of the chemical vapor deposition (CVD) systems that are used for semiconductor device manufacture [1]. At present, the development of real-time control for reactions within production-style reactor configurations is hampered by a number of issues: The nature, concentrations and physical distributions of the chemical species within the deposition chamber must be measurable for effective feedback control. These parameters are virtually uncharacterized at this time, even for processes that have been in use for prolonged periods [2]. The chemical kinetic relationships underlying the fabrication processes, while they have been modeled in certain cases have, in most instances, not been experimentally confirmed. These models are especially needed to effectively control particle nucleation within CVD reactors. The lack of chemical data on these systems is, at least in part, due to the fact that reliable, suitably configured sensors have not been generally available. The above impediments to real-time CVD reaction control are being eliminated. Fourier-transform infra-red (FT-IR) spectrometry is being used to provide the required sensing, and the chemical kinetic relationships involved in device manufacture are being understood and modeled. A prototype control system has been developed using an FT-IR sensor to control the reaction chemistry for a specific CVD process, and a plan for extending and commercializing this technology has been created. These recent accomplishments are described in this paper.