Developed by the Department of Electrical and Computer Engineering at Carnegie Mellon University, this technology has broad applications to semiconductor fabrication. The apparatus is monitored and controlled by a dedicated computer system. The control system collects sensor data on pressure, gas flow rates, plasma composition via mass spectrometry and temperature. Based on the observed data, gas flow rates, RF power levels, and chamber pressures are then adjusted in real time to control the deposition process.
Multivariable controllers afford greater control of the deposition process.
The control algorithm is frequently changed to develop new multivariable control algorithms. When implemented in software, the new controller may include faults in design or errors in the code. The reaction chamber is contaminated by excessive gas input. Hazardous gases are vented from the apparatus to the safety stack. These kinds of failures increase costs and reduce the availability of the apparatus for further testing.