Patent ID: 8343876

Claim:
A method of processing a semiconductor structure in a plasma processing chamber, comprising: a) supplying a first process gas into the plasma processing chamber while diverting a second process gas to a bypass-line, the plasma processing chamber containing a semiconductor substrate including at least one layer and a patterned resist mask overlying the layer; b) energizing the first process gas to produce a first plasma with a first impedance load and (i) etching at least one feature in the layer or (ii) forming a polymer deposit on the mask; c) frequency tuning a first RF power source to a first frequency to match the first impedance load; d) frequency tuning a second RF power source to a second frequency different than the first frequency to match the first impedance load; e) switching the flows of the first and second process gases so that the second process gas is supplied into the plasma processing chamber while diverting the first process gas to the by-pass line, the first process gas being substantially replaced in a plasma confinement zone of the plasma processing chamber by the second process gas within a period of less than about 1 s; f) energizing the second process gas to produce a second plasma with a second impedance load different from the first impedance load and (iii) etching the at least one feature in the layer or (iv) forming a polymer deposit on the layer and the mask; g) frequency tuning the first RF power source to a third frequency different than the first and second frequencies to match the second impedance load; h) frequency tuning the second RF power source to a fourth frequency different than the first, second, and third frequencies to match the second impedance load; i) switching the flows of the first and second process gases so that the first process gas is supplied into the plasma processing chamber while diverting the second process gas to the by-pass line, the second process gas being substantially replaced in the plasma confinement zone of the plasma processing chamber by the first process gas within a period of less than about 1 s; and j) repeating b)-i) a plurality of times with the substrate.