Oxide etch process with high selectivity to nitride suitable for use on surfaces of uneven topography
AssigneeApplied Materials, Inc.
InventorsChan-Lon Yang, Mei Chang, Paul Arleo, Haojiang Li, Hyman Levinstein
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Abstract
A plasma etch process is described for the etching of oxide with a high selectivity to nitride, including nitride formed on uneven surfaces of a substrate, e.g., on sidewalls of steps on an integrated circuit structure. The addition of a hydrogen-bearing gas to C4F8 or C2F6 etch gases and a scavenger for fluorine, in a plasma etch process for etching oxide in preference to nitride, results in a high selectivity to nitride which is preserved regardless of the topography of the nitride portions of the substrate surface.
Claims13
A method of plasma etching oxide in the presence of nitride capable of exhibiting high selectivity to nitride, including nitride on uneven surfaces, the method comprising:
- contacting the oxide with a gas mixture including C4F8 and CH3F in the presence of a silicon fluorine scavenger that is spaced from said oxide and nitride.
A method of plasma etching oxide in the presence of nitride capable of exhibiting high selectivity to nitride, including nitride on uneven surfaces, the method comprising:
- contacting the oxide with a gas mixture including C2F6 and C2H2 in the presence of a silicon fluorine scavenger.
A method of plasma etching oxide in the presence of nitride capable of exhibiting high selectivity to nitride, including nitride on uneven surfaces, the method comprising:
- contacting the oxide with a mixture of gases including C4F8 and one or more hydrogen-bearing gases selected from the group consisting of CH3F and CH2F2.
A method of plasma etching oxide in the presence of nitride capable of exhibiting high selectivity to nitride including nitride on uneven surfaces, the method comprising:
- contacting the oxide with a mixture of gases including
- a) one or more fluorine-substituted hydrocarbon etching gases selected from the group consisting of C4F8;
- b) one or more hydrogen-bearing gases selected from the group consisting of;
- in the presence of a silicon surface fluorine scavenger that is spaced from said oxide and nitride, said silicon surface fluorine scavenger being grounded.
Dependencies are inferred from the claim text.