Abstract: In a semiconductor process which utilizes a plasma within a process tool chamber, a method of using optical emission spectroscopy (OES) to monitor a particular parameter of the process is disclosed. A first wavelength present in the plasma is determined which varies highly in intensity depending on the particular parameter by observing a statistically significant sample representing variations of the particular parameter. A second wavelength of chemical significance to the process is also determined which is relatively stable in intensity over time irrespective of variations of the particular parameter, also by observing a statistically significant sample representing variations of the particular parameter. These two wavelengths may be determined from test wafers and off-line physical measurements.

Abstract: A method of forming low resistance contact structures in vias arranged between interconnect levels is provided. The method involves interconnect lines having an anti-reflective layer formed thereupon. An interlevel dielectric layer is formed over the interconnect lines. A photoresist layer is formed over the interlevel dielectric layer and patterned to define via locations. During via etch, an organic (carbon-based) polymer layer forms upon the anti-reflective-coated interconnect lines at the bottoms of the vias. The photoresist and the etch byproduct polymer layers are then removed using a dry etch process which employs a forming gas comprising nitrogen and hydrogen. A native oxide layer subsequently forms upon the anti-reflective-coated interconnect lines when exposed to oxygen. The native oxide layer is then removed, along with any residual etch byproduct polymer, during a sputter etch procedure.