Method for processing workpiece, plasma processing apparatus and semiconductor device

A method for processing a workpiece, comprising:

• placing the workpiece on a workpiece support in a chamber, wherein the workpiece comprises a spacer layer;
• selecting a composition modulation gas to modulate a volume ratio of carbon and fluorine to process the workpiece, wherein the composition modulation gas comprises:
• one or more molecules having a chemical formula CxHyFz, where x and z are natural numbers greater than zero, and y is a natural number greater than or equal to zero, wherein the volume ratio of carbon and fluorine is indicative of a distribution of carbon-based polymer deposited on the spacer layer;
• and
• one or more of Difluoromethane (CH2F2), Fluoroforni (CHF3), and Carbon tetrafluoride (CF4);
• generating one or more species using one or more plasmas from a process gas to create a mixture, wherein the process gas comprises:
• an etching gas and the composition modulation gas;
• and
• an inert gas;
• or, the process gas further comprises an inert gas and oxygen;
• exposing the workpiece to the mixture to form a polymer layer on at least a portion of the spacer layer and to etch at least a portion of the spacer layer of the workpiece, wherein a volume proportion of each component in the process gas is as follows:
• the etching gas:
• about 10%-about 30%;
• the composition modulation gas:
• about 5%-about 25%;
• the oxygen:
• about 3%-about 10%;
• and
• the inert gas:
• about 50%-about 80%.

A method for processing a workpiece, comprising:

• placing the workpiece on a workpiece support in a chamber, wherein the workpiece comprises a spacer layer;
• selecting a composition modulation gas to modulate a volume ratio of carbon and fluorine to process the workpiece, wherein the composition modulation gas comprises one or more molecules having a chemical formula CxHyFz where x and z are natural numbers greater than zero, and y is a natural number greater than or equal to zero, wherein the volume ratio of carbon and fluorine is indicative of a distribution of carbon-based polymer deposited on the spacer layer;
• generating one or more species using one or more plasmas from a process gas to create a mixture, wherein the process gas comprises an etching has and the composition modulation gas;
• and
• exposing the workpiece to the mixture to form a polymer layer on at least a portion of the spacer layer and to etch at least a portion of the spacer layer of the workpiece, wherein a processing parameter of the chamber comprises one or more of:
• a pressure:
• about 5 mTorr-about 70 mTorr;
• a source power:
• about 100 watts-about 500 watts;
• a center power:
• about 50 watts-about 200 watts;
• and
• a bias power:
• about 100 watts-about 500 watts.

A method for processing a workpiece, comprising:

• placing the workpiece on a workpiece support in a chamber, wherein the workpiece comprises a spacer layer;
• selecting a composition modulation gas to modulate a volume ratio of carbon and fluorine to process the workpiece, wherein the composition modulation gas comprises one or more molecules having a chemical formula CxHyFz, where x and z are natural numbers greater than zero and y is a natural number greater than or equal to zero, wherein the volume ratio of carbon and fluorine is indicative of a distribution of carbon-based polymer deposited on the spacer layer;
• generating one or more species using one or more plasmas from a process gas to create a mixture, wherein the process gas comprises an etching gas and the composition modulation gas;
• and
• exposing the workpiece to the mixture to form a polymer layer on at least a portion of the spacer layer and to etch at least a portion of the spacer layer of the workpiece wherein generating the one or more species further comprises:
• providing a first radio frequency (RF) power to an induction coil to generate a first plasma from the process gas to generate a first mixture in the chamber, the first mixture comprising one or more first species;
• and
• providing a second RF power to a bias electrode to generate a second plasma in the first mixture in the chamber to generate a second mixture, the second mixture comprising one or more second species,
• wherein exposing the workpiece to the mixture comprises exposing the workpiece to the second mixture.