Abstract: A method and system for use in monitoring/evaluating industrial processes such as, for example, plasma processes are provided. In one embodiment, a plasma process fault detection module (100) includes multiple sub-modules. A data selection sub-module (101) obtains selected optical emissions spectra (OES) data for each wafer that is processed. A model building/updating sub-module (102) constructs multiple models from the OES data for a number of wafers. A principal component analysis (PCA) analysis sub-module (103) utilizes PCA techniques to determine whether the OES data for a particular wafer differs significantly from an expected normal wafer as represented by the models. A model maintenance sub-module (104) saves and retrieves models for different processes, associating the current wafer with the correct process. A wafer categorization sub-module (105) categorizes each wafer based on a scalar metric characterizing the residual spectrum vector. A data output sub-module (106) outputs the results to a user.

Abstract: Flat, insulated, metallic strips ("applicators"), are fixed to the wider sides of each permanent magnet assembly in the channel array of a Magnetohydrodynamic (MHD) Vacuum Pump. Electromagnetic power from an external rf/microwave generator is delivered by an appropriate transmission line to each pair of applicators, providing an rf/microwave electric field, generally parallel to the magnetic field of the magnets, across each channel in the array. As the plasma ions and electrons formed by the rf/microwave field lose energy by collisions with the channel surfaces and by collisions with neutral molecules in the channel, the microwave electric field reheats the plasma throughout its passage through the length of the channel array, increasing plasma density and enabling the use of much longer channels, thus increasing the throughput and compression ratio in the MHD Vacuum Pump.

Abstract: The invention enables real-time control of a process using information regarding process properties that are indirectly related to the state of the process. A set of properties that characterize the process environment (fingerprint) is measured and used by a process results estimator to infer information regarding the state of the process and by a process condition monitor for monitoring the process to ascertain whether a particular type of condition exists. In one embodiment, optical emission spectra (OES) are used as the fingerprint. The process results estimator is sufficiently powerful to enable the process state to be inferred even when the relationship between the process environmental properties and the process state is complicated and difficult to describe with traditional mathematical models. In one embodiment, the process results estimator is embodied by a neural network. The process condition monitor can also be embodied by a neural network.

Abstract: This invention relates to the technology of preparing a vacuum by removing gases from an enclosed volume and to the use of magnetized plasma as the working fluid in a vacuum pump. The pumping action is created by ionizing the gas to be pumped with microwave radiation and then by exerting magnetohydrodynamic forces on the plasma to flow through a region of constricted space which impedes the backflow of neutral gas thus causing compression of the gas in the exit region. The magnetohydrodynamic forces arise as the vector product of a plasma current j and a magnetic field B, which are imposed on the plasma by a structure of electrodes and permanent magnets. The geometry of this structure is such that the magnetic force and the plasma current between electrodes are approximately perpendicular to each other and to the axis of the device. The resulting j.times.B force then creates an axial plasma flow and neutral compression.