Mixed mode pulsing etching in plasma processing systems

A plasma processing system for processing a substrate using mixed-mode pulsing, the plasma processing system comprising:

• a substrate;
• a plasma processing chamber for processing the substrate;
• a work piece holder within an interior region of the plasma processing chamber;
• at least one plasma generating source;
• at least one reactive gas source for providing at least a first reactive gas into the interior region of the plasma processing chamber;
• at least one non-reactive gas source for providing at least a first non-reactive gas into the interior region of the plasma processing chamber;
• and
• a tangible computer-readable medium storing computer-readable instructions for:
• (a) disposing the substrate on a work piece holder within the interior region;
• (b) performing a mixed-mode pulsing (MMP) preparation phase, including flowing the first reactive gas into the interior region, and
• forming a first plasma with at least the first reactive gas to process the substrate with the first plasma;
• (c) performing a mixed mode pulsing (MMP) reactive phase, including flowing at least the first non-reactive gas into the interior region, and
• forming a second plasma with at least the first non-reactive gas to process the substrate with the second plasma, wherein the second plasma is formed with a flow of the first reactive gas during the MMP reactive phase that is less than a flow of the first reactive gas during the MMP preparation phase, wherein the plasma processing chamber is configured during the MMP reactive phase to generate non-reactive ions having a level of ion energy that is higher than required to etch an adsorbed layer on a surface of the substrate but insufficient to etch a non-adsorbed layer of the substrate, the adsorbed layer formed during the MMP preparation phase;
• and
• (d) repeating steps (b) and (c) for a plurality of times.

A plasma processing system for processing a substrate using mixed-mode pulsing, the plasma processing system comprising:

• a substrate;
• a plasma processing chamber for processing the substrate;
• a work piece holder within an interior region of the plasma processing chamber;
• at least one reactive gas source for providing at least a first reactive gas into the interior region of the plasma processing chamber;
• at least one non-reactive gas source for providing at least a first non-reactive gas into the interior region of the plasma processing chamber;
• at least one gas pulsing valve for flowing a first reactive gas into the interior region during a mixed-mode pulsing (MMP) preparation phase;
• at least one gas pulsing valve for flowing a first non-reactive gas into the interior region during a mixed-mode pulsing (MMP) reactive phase;
• and,
• at least one plasma generating source comprising a pulse-capable RF power supply;
• and,
• a tangible computer-readable medium storing computer-readable instructions for:
• (a) flowing the first reactive gas during the MMP reactive phase at a flow rate that is less than the flow rate of the first reactive gas during the MMP preparation phase;
• and,
• (b) for supplying an RF signal having chirped frequencies to excite the first reactive gas during the MMP preparation phase.