| CPC H01L 21/3065 (2013.01) [H01J 37/32174 (2013.01); H01J 2237/3346 (2013.01)] | 25 Claims |
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1. A method for performing an etch process on a substrate in a plasma processing system, comprising:
applying a bias signal to an electrode of the plasma processing system; and
applying a source signal to the electrode;
wherein the bias signal and the source signal are pulsed RF signals that together define a repeated pulsed RF cycle, wherein each pulsed RF cycle sequentially includes a first state, a second state, a third state, and a fourth state;
wherein the first state is defined by the bias signal being pulsed at a first bias power level and the source signal being pulsed at a first source power level;
wherein the second state is defined by the bias signal being pulsed at a second bias power level and the source signal being pulsed at a second source power level;
wherein the third state is defined by the bias signal being pulsed at a third bias power level and the source signal being pulsed at a third source power level;
wherein the fourth state is defined by the bias signal being pulsed at a fourth bias power level and the source signal being pulsed at a fourth source power level;
wherein the first bias power level is greater than the third bias power level, and the third bias power level is greater than the second bias power level, and the second bias power level is greater than the fourth bias power level;
wherein the first source power level is greater than the third source power level, and the third source power level is greater than the second source power level, and the second source power level is greater than the fourth source RF power level.
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