Plasma etch is a semiconductor manufacturing process during which material is removed from the surface of semiconducting, typically silicon, wafers using gases in plasma form. A host of chemical and electrical complexities make the etch...
morePlasma etch is a semiconductor manufacturing process during which material is removed from the surface of semiconducting, typically silicon, wafers using gases in plasma form. A host of chemical and electrical complexities make the etch process notoriously dicult to model and troublesome to control. This work
demonstrates the use of a real-time model predictive control scheme to control plasma electron density and plasma etch rate in the presence of disturbances to the ground path of the chamber. Virtual metrology (VM) models, using plasma impedance measurements, are used to estimate the plasma electron density and plasma etch rate in real time for control, eliminating the requirement for invasive measurements. The virtual metrology and control schemes exhibit fast set-point tracking and disturbance rejection capabilities. Etch rate can be controlled to within 1% of the desired value.
