Controlled etching of oxides via gas phase reactions
View Patent ↗Oxides are etched with a halide-containing species and a low molecular weight organic molecule having a high vapor pressure at standard conditions, where etching is performed at preset wafer temperature in an enclosed chamber at a pressure such that all species present in the chamber, including water, are in the gas phase and condensation of species present on the etched surface is controlled. Thus all species involved remain in the gas phase even if trace water vapor appears in the process chamber. Preferably, etching is performed in a cluster dry tool apparatus.
1. A method of etching oxides on a surface of a substrate, said substrate being at a temperature from 30 ° C. to 70 ° C., said method comprising etching with a gas phase mixture of a halide-containing species, an organic material having a higher vapor pressure than water at standard conditions of room temperature and pressure of 1 atmosphere and water, in an enclosed chamber at a pressure such that HF and acetone in an enclosed chamber at a pressure of 500 Torr such that a reaction product water is substantially maintained in the gas phase and condensation of species present on the etched surface is minimized.
2. A method of etching as claimed in claim 1 where the etching is performed in an enclosed chamber of a cluster dry tool apparatus.
3. A method of etching as claimed in claim 1 where the organic material having a higher vapor pressure than water at standard conditions of room temperature and pressure of 1 atmosphere is selected from the group consisting of alcohols, organic acids, ketones and alkanes.
4. A method of etching as claimed in claim 3 where the organic material having a higher vapor pressure than water at standard conditions of room temperature and pressure of 1 atmosphere in selected from the group consisting of methanol, isopropanol, acetone, acetic acid and methane.
5. A method of etching as claimed in claim 1 where the halide-containing species is selected from the group consisting of HF, NF 3 , ClF 3 and F 2 .
6. A method of etching as claimed in claim 1 where the halide-containing species is HF, the organic material having a higher vapor pressure than water at standard conditions of room temperature and pressure of 1 atmosphere is methanol, the pressure is 100 Torr and the preset temperature is from 20° C. to 95° C.
7. A method of etching as claimed in claim 1 where the halide-containing species is HF, the organic material having a higher vapor pressure than water at standard conditions of room temperature and pressure of 1 atmosphere is methanol, the pressure is 300 Torr and the temperature is from 80° C. to 95° C.
8. A method of etching as claimed in claim 1 where the halide-containing species is HF, the low molecular weight organic molecule having a higher vapor pressure than water at standard conditions of room temperature and pressure of 1 atmosphere is methanol, the pressure is 500 Torr and the preset temperature is from 95° C. to 105° C.
9. A method of etching as claimed in claim 1 where the etching is performed in an enclosed chamber which is a reactor body of an apparatus further comprising:
a gas delivery system;
a UV source;
an IR source;
a rotating mechanism to rotate the wafer; and
a vacuum control system.
10. A method of etching as claimed in claim 1 where the organic material having a higher vapor pressure than water at standard conditions of room temperature and pressure of 1 atmosphere is anhydrous.
11. A method of etching as claimed in claim 1 where the halide-containing species is anhydrous.
12. A method of etching oxides on a surface of a substrate, said substrate being at a temperature of from 30° C. to 70° C., said method comprising etching with a gas phase mixture of HF and acetone, in an enclosed chamber at a pressure of 500 Torr such that water is substantially maintained in the gas phase and condensation of species present on the etched surface is minimized.