Etching of metal oxides using fluorine and metal halides
Embodiments of this disclosure provide methods for etching oxide materials. Some embodiments of this disclosure provide methods which selectively etch oxide materials over other materials. In some embodiments, the methods of this disclosure are performed by atomic layer etching (ALE). In some embodiments, the methods of this disclosure are performed within a processing chamber comprising a nickel chamber material.
1. An etch process comprising:
exposing a substrate surface having a hafnium oxide layer thereon to a fluorinating agent to form a fluoride layer on the hafnium oxide layer; and
exposing the fluoride layer to a halide etchant to remove the fluoride layer, the halide etchant comprising a compound having the general formula EX 3 , where E comprises one or more of aluminum (Al) or boron (B), and X comprises one or more of Cl, Br or I, wherein the substrate surface has at least one other material which comprises one or more of TiN, TaN, SiN, SiO 2 , Al 2 O 3 , or carbon-based materials and the hafnium oxide layer is selectively etched over the at least one other material and wherein selectivity of the etch process is greater than or equal to about 10:1.
2. The etch process of claim 1 , wherein the fluorinating agent comprises one or more of organofluorides having the general formula C x H y F z , where x is 1-16, y is 0-33 and z is 1-34, organooxyfluorides having the general formula C x H y O w F z , where x is 1-16, y is 0-33, w is 1-8 and z is 1-34, metal fluorides, or combinations thereof.
3. The etch process of claim 1 , wherein E comprises boron (B).
4. The etch process of claim 1 , wherein E comprises aluminum (Al).
5. The etch process of claim 1 , further comprising repeating exposures to the fluorinating agent and halide etchant to remove a predetermined thickness of the hafnium oxide layer.
6. The etch process of claim 1 , wherein the fluorinating agent is coflowed with hydrogen (H 2 ) and the fluoride layer has a thickness in a range of about 10 Å to about 15 Å.
7. The etch process of claim 6 , wherein the fluoride layer is formed in a process chamber comprising a nickel chamber material.
8. The etch process of claim 1 , further comprising exposing the substrate surface to a cleaning plasma comprising one or more radicals of H*, OH*, O* or H 2 O* before exposing the substrate surface to the fluorinating agent.
9. The etch process of claim 8 , wherein the cleaning plasma removes a carbon film and/or moisture from the substrate surface.
10. The etch process of claim 9 , wherein the carbon film and/or moisture is a result of an etch process.