Method for selective etching of oxides
First Claim
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1. A method for plasma etching a semiconductor substrate, comprising:
- introducing a gaseous mixture containing NH3, NF3 and O2 into a plasma source chamber, said plasma source chamber being situated upstream of a plasma chamber containing a semiconductor substrate;
generating a plasma of said gaseous mixture in said plasma source chamber;
flowing said plasma downstream of said plasma source chamber, and into said plasma chamber; and
contacting said substrate with said plasma.
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Abstract
An improved dry plasma cleaning process for the removal of native oxides, or other oxide films or growth residue, from openings formed in an insulating layer provided over a semiconductor substrate, without damaging the substrate or significantly affecting the critical dimension of the opening is disclosed. A mixture of nitrogen trifluoride (NF3), ammonia (NH3) and oxygen (O2) is first injected upstream into a microwave plasma source and is exited, and then the plasma is flowed downstream from the plasma source into a reaction chamber containing the substrate.
178 Citations
25 Claims
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1. A method for plasma etching a semiconductor substrate, comprising:
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introducing a gaseous mixture containing NH3, NF3 and O2 into a plasma source chamber, said plasma source chamber being situated upstream of a plasma chamber containing a semiconductor substrate;
generating a plasma of said gaseous mixture in said plasma source chamber;
flowing said plasma downstream of said plasma source chamber, and into said plasma chamber; and
contacting said substrate with said plasma. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for cleaning a contact opening provided in an insulating layer formed over a substrate, said method comprising:
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placing said substrate and said insulating layer into a plasma chamber, said insulating layer having at least one contact opening therein;
introducing a gaseous mixture containing NH3, NF3 and O2 into a plasma source chamber, said plasma source chamber being situated upstream of said plasma chamber;
generating a plasma of said gaseous mixture in said plasma source chamber;
flowing said plasma downstream of said plasma source chamber into said plasma chamber; and
contacting said insulating layer with said plasma to clean at least a bottom of said opening with said plasma. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A method for removing a native oxide formed inside of a contact opening provided within an insulating layer formed over a semiconductor substrate, said method comprising:
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introducing a gaseous mixture containing, NH3, NF3 and O2 into a plasma source chamber, said plasma source chamber being situated upstream of a plasma chamber containing a semiconductor substrate;
generating a plasma of said gaseous mixture into said plasma source chamber;
flowing said plasma downstream of said plasma source chamber, and into said plasma chamber; and
contacting said contact opening with said plasma to remove said native oxide from at least a bottom of said opening. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A method for etching an undoped oxide provided on a semiconductor substrate relative to a doped oxide provided on said semiconductor substrate, said method comprising:
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introducing a gaseous mixture containing NH3, NF3 and O2 into a plasma source chamber, said plasma source chamber being situated upstream of a plasma chamber containing said first and second semiconductor substrate;
generating a plasma of said gaseous mixture in said plasma source chamber;
flowing said plasma downstream of said plasma source chamber, and into said plasma chamber; and
contacting said first and second semiconductor substrates with said plasma. - View Dependent Claims (22, 23, 24, 25)
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Specification