SENSOR INTEGRATION INTO PLASMA ETCH REACTORS OF A DEVELOPMENTAL PILOTLINE

During the course of the Microelectronics Manufacturing Science and Te chnology (MMST) program, a number of sensors have been integrated into various test-bed plasma etch reactors with the goal of monitoring, di agnosing, and controlling these processes. These sensors include singl e wavelength and spectral ellipsometers for real-time in situ etch rat e and endpoint determination; a standard monochromator for etch rate a nd nonuniformity measurements; an eddy current sensor for incoming met al thickness control; a rf monitor for rf current and voltage diagnost ics; and a scatterometry-based critical dimension sensor for linewidth measurements. The full integration of these sensors turned out to be a complex and time-consuming task including hardware, optical, softwar e, material, and processing issues. Once integrated into the reactor, and the appropriate process modeling completed, these sensors enabled the monitoring, diagnosis, and model-based control of these processes. Besides maintaining specific process observables at their target valu es, running under process control has highlighted phenomena such as eq uipment aging and first-wafer effects. This work has clearly shown tha t the full implementation of sensors into commercial manufacturing equ ipment is essential for the model-based control and diagnosis of semic onductor processes.