Selective etch using a sacrificial mask
A method for selectively etching a silicon oxide region with respect to a lower oxygen silicon containing region is provided. A sacrificial mask selectively deposited on the lower oxygen silicon containing region with respect to the silicon oxide region. An atomic layer etch selectively etches the silicon oxide region with respect to the sacrificial mask on the lower oxygen silicon containing region.
1. A method for selectively etching a silicon oxide region with respect to a lower oxygen silicon containing region, comprising:
a) selectively depositing a sacrificial mask on the lower oxygen silicon containing region with respect to the silicon oxide region; and
b) selectively etching with an atomic layer etch the silicon oxide region with respect to the sacrificial mask on the lower oxygen silicon containing region, comprising a plurality of cycles, wherein each cycle, comprises:
i) providing a reactant gas to selectively form a deposition layer on the silicon oxide region;
ii) purging the reactant gas; and
iii) providing an activation gas causing the deposition layer to be activated resulting in at least partially etching the silicon oxide region and the sacrificial mask.
2. The method, as recited in claim 1 , wherein steps a and b are repeated a plurality of times.
3. The method, as recited in claim 1 , wherein the lower oxygen silicon containing region is at least one of silicon, silicon carbide, silicon nitride, silicon oxynitride, silicon carbonitride and silicon oxycarbonitride.
4. The method as recited in claim 1 , further comprising selectively depositing an inhibitor layer on the silicon oxide region, wherein the sacrificial mask is based on at least one of a metal oxide, metal carbide, or metal nitride, wherein the at least one of a metal oxide, metal carbide, or metal nitride is deposited selectively onto the lower oxygen containing film while being delayed from deposition on the silicon oxide region by the inhibitor layer.
5. The method, as recited in claim 4 , wherein the at least one of a metal oxide, metal carbide, or metal nitride is deposited by an atomic layer deposition process, using a cyclic process comprising a metal containing precursor step and a reactant step.
6. The method as recited in claim 5 , wherein the metal containing precursor step comprises depositing a metal containing precursor containing at least one of tungsten, molybdenum, titanium, zirconium, hafnium, antimony, vanadium, tantalum, aluminum, yttrium, or nickel.
7. The method, as recited in claim 5 , wherein the reactant step comprises providing a reactant that is at least one of an oxygen containing reactant, a nitrogen containing reactant, or a carbon containing reactant.
8. The method, as recited in claim 5 , further comprising providing a purge between the metal containing precursor step and the reactant step.
9. The method, as recited in claim 5 , wherein the sacrificial mask comprises hafnium dioxide.
10. The method, as recited in claim 9 , wherein the metal containing precursor step comprises depositing a metal containing precursor of at least one of hafnium(IV) tert-butoxide, tetrakis(diethylamido) hafnium (IV), tetrakis(dimethylamido) hafnium (IV), tetrakis(ethylmethylamido) hafnium (IV), hafnium tetrachloride and wherein the reactant step comprises providing a reactant that is at least one of water vapor, oxygen, peroxide, or ozone.
11. The method, as recited in claim 5 , wherein the sacrificial mask comprises zirconium dioxide.
12. The method, as recited in claim 11 , wherein the metal containing precursor step comprises depositing a metal containing precursor of at least one of zirconium (IV) tert-butoxide, tetrakis(diethylamido) zirconium (IV), tetrakis(dimethylamido) zirconium (IV), tetrakis(ethylmethylamido) zirconium (IV), zirconium tetrachloride and wherein the reactant step comprises providing a reactant that is at least one of water vapor, oxygen, peroxide, or ozone.
13. The method, as recited in claim 5 , wherein the sacrificial mask comprises titanium oxide.
14. The method, as recited in claim 13 , wherein the metal containing precursor step comprises depositing a metal containing precursor of at least one of titanium(IV) isopropoxide, tetrakis(diethylamido)titanium(IV), tetrakis(dimethylamido)titanium(IV), tetrakis(ethylmethylamido)titanium(IV), titanium tetrachloride and wherein the reactant step comprises providing a reactant that is at least one of water vapor, oxygen, peroxide, or ozone.
15. The method, as recited in claim 4 , wherein the selectively depositing the inhibitor layer comprises depositing a self assembled monolayer that selectively deposits on the silicon oxide region with respect to the lower oxygen silicon containing region.
16. The method, as recited in claim 4 , further comprising cleaning the silicon oxide region and lower oxygen silicon containing region with a gaseous or aqueous solution of hydrogen fluoride before depositing the inhibitor layer.
17. The method, as recited in claim 4 , further comprising providing a clean after depositing the sacrificial mask.
18. The method, as recited in claim 4 , further comprising providing a pre-treatment after depositing the inhibitor layer and before depositing the sacrificial mask, wherein the pre-treatment enhances reactive sites of the lower oxygen silicon containing region by activation or deactivates the inhibitor layer.
19. A method for selectively etching a silicon or SiN region with respect to a higher oxygen containing region with an OH surface termination, comprising:
a) selectively depositing a sacrificial mask on the higher oxygen containing region with respect to the silicon or SiN region; and
b) selectively etching the silicon or SiN region with respect to the sacrificial mask on the higher oxygen containing region, comprising a plurality of cycles, wherein each cycle, comprises:
i) providing a reactant gas to selectively form a deposition layer on the silicon oxide region;
ii) purging the reactant gas; and
iii) providing an activation gas causing the deposition layer to be activated resulting in at least partially etching the silicon oxide region and the sacrificial mask.
20. The method as recited in claim 19 , wherein the sacrificial mask comprises a metal oxide, wherein the metal oxide is deposited selectively onto the higher oxygen containing region.
21. The method, as recited in claim 20 , wherein the metal oxide comprises a titanium oxide deposited by a thermal ALD process, using a cyclic process between a Ti containing precursor and an oxidizer used to deposit the titanium oxide, wherein the oxidizer is at least one of water vapor, oxygen, peroxide, or ozone.