Selective etching of oxides
First Claim
1. A method for treating a surface comprising:
- forming a surface situated on a semiconductor substrate, said surface having exposed doped silicon dioxide; and
exposing said surface with said exposed doped silicon dioxide to a vapor phase solution comprising an initiator gas, hydrogen fluoride and ammonia, wherein said vapor phase solution etches thermal oxides at least one-half the rate at which said vapor phase solution etches said doped silicon dioxide.
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Accused Products
Abstract
A surface having exposed doped silicon dioxide such as BPSG is cleaned with a vapor phase solution that etches thermal oxide at least one-third as fast as it etches the exposed doped silicon dioxide, resulting in more thorough cleaning with less removal of the exposed doped silicon dioxide. Specific applications to formation of container capacitors are disclosed. Preferred cleaning vapor phase solutions include about 1% water, about 5% hydrogen fluoride, and about 5% ammonias. The vapor phase solution is also useful in cleaning methods in which a refractory metal silicide is exposed to the cleaning vapor phase solution such as in cleaning prior to spacer formation or prior to a gate stack contact fill, in which case about 500 PPMV water, about 2% hydrogen fluoride, and about 2% ammonia is most preferred.
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Citations
31 Claims
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1. A method for treating a surface comprising:
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forming a surface situated on a semiconductor substrate, said surface having exposed doped silicon dioxide; and exposing said surface with said exposed doped silicon dioxide to a vapor phase solution comprising an initiator gas, hydrogen fluoride and ammonia, wherein said vapor phase solution etches thermal oxides at least one-half the rate at which said vapor phase solution etches said doped silicon dioxide. - View Dependent Claims (2, 3, 4, 20, 22)
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5. A method for treating surfaces, said method comprising:
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forming a first surface situated on a semiconductor substrate, said first surface having exposed doped silicon dioxide; forming a second surface situated on a semiconductor substrate, said second surface having exposed refractory metal silicide; forming a third surface situated on a semiconductor substrate, said third surface having exposed thermal oxide; and exposing said first, second, and third surfaces to a vapor phase solution comprising an initiator gas, hydrogen fluoride and ammonia, and wherein; said exposed refractory metal silicide is not substantially etched; said vapor phase solution removes thermal oxide at least one-half the rate at which said vapor phase solution removes said doped silicon dioxide; and said exposed refractory metal silicide is not substantially removed. - View Dependent Claims (6, 7, 23)
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8. A method for providing a recess, said method comprising:
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providing a silicon substrate having a layer of doped silicon dioxide formed thereover, said silicon substrate having a source/drain region defined therein; forming in said layer of doped silicon dioxide a recess extending down through said layer of doped silicon dioxide to said source/drain region; exposing said source/drain region to a vapor phase solution comprising hydrogen fluoride, ammonia, and an initiator gas, and having an etch rate for thermal oxide of at least one-half of the etch rate of said vapor phase solution for said layer of doped silicon dioxide; forming a layer of conductive material over said silicon substrate and said layer of doped silicon dioxide to contact said source/drain region; and removing said layer of conductive material from the top thereof downward to at least the topmost surface of said layer of doped silicon dioxide, leaving in said recess a portion of said layer of conductive material. - View Dependent Claims (9, 10, 11, 12)
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13. A method for treating a surface situated on a semiconductor substrate, said method comprising:
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performing a chemical mechanical polishing upon a semiconductor substrate to expose a doped silicon dioxide and a silicon on a surface of said semiconductor substrate; exposing said doped silicon dioxide and said silicon on said surface of said semiconductor substrate to a vapor phase solution having an etch rate for thermal oxide of at least one-half of the etch rate of said vapor phase solution for said layer of doped silicon dioxide, wherein said vapor phase solution comprises an initiator gas that is substantially composed of a material selected from a group consisting of H2 O, CH3 OH, C3 H6 O, and C3 H8 O in the range of about 2% to about 20% hydrogen fluoride, and about 2% to 20% ammonia, wherein said doped silicon dioxide is not substantially etched. - View Dependent Claims (14, 15, 16, 17, 18, 19, 21)
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24. A method of treating materials situated on a semiconductor substrate comprising:
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forming a first surface situated on a semiconductor substrate, said first surface having exposed doped silicon dioxide; forming a second surface situated on said semiconductor substrate, said second surface having exposed refractory metal silicide; forming a third surface situated on said semiconductor substrate, said third surface having exposed thermal oxide; and exposing said first, second, and third surfaces to a vapor phase solution comprising hydrogen fluoride, ammonia, and an said initiator gas that is substantially composed of a material selected from a group consisting of H2 O, CH3 OH, C3 H6 O, and C3 H8 O, wherein said vapor phase solution removes thermal oxide at least one-half the rate at which said vapor phase solution removes said doped silicon dioxide, and wherein said exposed refractory metal silicide is not substantially removed. - View Dependent Claims (25, 26)
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27. A method for treating a surface comprising:
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forming a surface situated on a semiconductor substrate, said surface having exposed doped silicon dioxide; and exposing said surface with said exposed doped silicon dioxide to a vapor phase solution comprising hydrogen fluoride, ammonia, and an initiator gas composed of a material selected from a group consisting of H2 O, CH3 OH, C3 H6 O, and C3 H8 O, wherein said vapor phase solution etches thermal oxides at least one-half the rate at which said vapor phase solution etches said doped silicon dioxide.
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28. A method for treating surfaces, said method comprising:
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forming a first surface situated on a semiconductor substrate, said first surface having exposed doped silicon dioxide; forming a second surface situated on a semiconductor substrate, said second surface having exposed refractory metal silicide; forming a third surface situated on a semiconductor substrate, said third surface having exposed thermal oxide; and exposing said first, second, and third surfaces to a vapor phase solution comprising an hydrogen fluoride, ammonia, and an initiator gas composed of a material selected from a group consisting of H2 O, CH3 OH, C3 H6 O, and C3 H8 O, wherein; said exposed refractory metal silicide is not substantially etched; said vapor phase solution removes thermal oxide at least one-half the rate at which said vapor phase solution removes said doped silicon dioxide; and said exposed refractory metal silicide is not substantially removed.
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29. A method for providing a recess, said method comprising:
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providing a silicon substrate having a layer of doped silicon dioxide formed thereover, said silicon substrate having a source/drain region defined therein; forming in said layer of doped silicon dioxide a recess extending down through said layer of doped silicon dioxide to said source/drain region; exposing said source/drain region to a vapor phase solution comprising water, about 2% to 20% hydrogen fluoride, and about 2% to 20% ammonia, and having an etch rate for thermal oxide of at least one-half of the etch rate of said vapor phase solution for said layer of doped silicon dioxide; forming a layer of conductive material over said silicon substrate and said layer of doped silicon dioxide to contact said source/drain region; and removing said layer of conductive material from the top thereof downward to at least the topmost surface of said layer of doped silicon dioxide, leaving in said recess a portion of said layer of conductive material.
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30. A method for treating a surface situated on a semiconductor substrate, said method comprising:
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performing a chemical mechanical polishing upon a semiconductor substrate to expose a doped silicon dioxide and a silicon on a surface of said semiconductor substrate; exposing said doped silicon dioxide and said silicon on said surface of said semiconductor substrate to a vapor phase solution having an etch rate for thermal oxide of at least one-half of the etch rate of said vapor phase solution for said layer of doped silicon dioxide, wherein said vapor phase solution comprises about 1% water, about 5% hydrogen fluoride, and about 5% ammonia, wherein said doped silicon dioxide is not substantially etched.
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31. A method for treating a surface situated on a semiconductor substrate, said method comprising:
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performing a chemical mechanical polishing upon a semiconductor substrate to expose a doped silicon dioxide and a silicon on a surface of said semiconductor substrate; exposing said doped silicon dioxide and said silicon on said surface of said semiconductor substrate to a vapor phase solution having an etch rate for thermal oxide of at least one-half of the etch rate of said vapor phase solution for said layer of doped silicon dioxide, wherein said vapor phase solution comprises about 1% water, about 2% hydrogen fluoride, and about 2% ammonia, wherein said doped silicon dioxide is not substantially etched.
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Specification