Rapid thermal multiprocessing for a programmable factory for adaptable manufacturing of ICs

Abstract

Absfruct-This paper presents an overview of research at Stanford University on the development of concepts of a programmable factory, based on a new generation of flexible multifunctional equipment implemented in a smaller flexible factory. This approach is demonstrated through the development of a novel single wafer Rapid Thermal Multiprocessing (RTM) reactor with extensive integration of sensors, computers and related technology for specification, communication, execution, monitoring, control, and diagnosis to demonstrate the programmable nature of the RTM. The RTM combines rapid thermal processing and several other process environments in a single chamber, with applications for multilayer in-situ growth and deposition of dielectrics, semiconductors and metals. Because it is highly instrumented, the RTM is very flexible for in-situ multiprocessing, allowing rapid cycling of ambient gases, temperature, pressure, etc. It allows several processing steps to be executed sequentially in-situ, while providing sufficient flexibility to allow optimization of each processing step. This flexibility is partially the result of a new lamp system with three concentric rings each of which is independently and dynamically controlled to provide for better control over the spatial and temporal optical flux profile resulting in excellent temperature uniformity over a wide range of process conditions namely temperatures, pressures and gas flow rates. The lamp system has been optimally designed through the use of a newly developed thermal simulator. For equipment and process control, a variety of sensors for real-time measurements and a model based control system have been developed. The acoustic sensors noninvasively allow a complete wafer temperature tomography under all process conditioncritically important measurement never obtained before. In an exemplary demonstration of multiprocessing, we have integrated three different processes with disparate process conditions-cleaning, thermal oxidation and CVD of silicon-sequentially in-situ. This technology integrates an entire MOS capacitor stack into one process chamber as opposed to three stand alone pieces of equipment needed in conventional technology. This will result in reduced cost of the factory, reduction in cycle time and may provide better device characteristics, since the interfaces between the semiconductor, gate dielectric and gate electrode are free of contamination from the room ambient. In general, adaptable

Application of neural fuzzy network to pyrometer correction and temperature control in rapid thermal processing

“…Reference [14] showed this was due to differences between expected and actual deposition rates. An alternative approach has been the use of the temperature dependence of acoustic wave speed [12]. There are also a variety of approaches based on measuring the thermal expansion of wafer [13].…”