Hybridization fin reveal for uniform fin reveal depth across different fin pitches
A method for uniform fin reveal depth for semiconductor devices includes dry etching a dielectric material to reveal semiconductor fins by a quasi-atomic layer etching (quasi-ALE) process to achieve depth uniformity across different fin pitches. A lateral bias induced by the quasi-ALE process is compensated for by isotropically etching the dielectric material.
1. A method for uniform fin reveal depth for semiconductor devices, comprising:
dry etching a dielectric material to reveal semiconductor fins by a quasi-atomic layer etching (quasi-ALE) process to achieve depth uniformity across different fin pitches wherein the quasi-ALE process includes a plurality of gas and bias pulse cycles of depositing a polymer with embedded etchant and removing the polymer to release the etchant to remove the dielectric material; and
compensating for a lateral bias induced by the quasi-ALE process by isotropically etching the dielectric material.
2. The method as recited in claim 1 , wherein the quasi-ALE process laterally etches isolation regions without fins slower than dense fin regions, and the isotropically etching reversely laterally etches the isolation regions faster than the dense fin regions.
3. The method as recited in claim 1 , wherein isotropically etching includes a plasma free reactive cleaning or remote plasma etch.
4. The method as recited in claim 1 , further comprising a plasma strip to remove collected polymer from the quasi-ALE process.
5. The method as recited in claim 4 , wherein the plasma strip includes N 2 H 2 or O 2 plasma.
6. The method as recited in claim 1 , further comprising deglazing the dielectric material to remove footings at the base of the fins formed during the dry etching to achieve the depth uniformity across different fin pitches.
7. A method for uniform fin reveal depth for semiconductor devices, comprising:
forming a liner over semiconductor fins and a substrate;
forming one or more dielectric materials over the liner;
dry etching the one or more dielectric materials to reveal semiconductor fins by a quasi-atomic layer etching (quasi-ALE) process to achieve depth uniformity across different fin pitches and different material types or qualities;
isotropically etching the one or more dielectric materials with a plasma free reactive cleaning or remote plasma etch to compensate for lateral bias induced by the quasi-ALE process;
deglazing the one or more dielectric materials to remove footings at the base of the fins formed during the dry etching to achieve the depth uniformity across different fin pitches and material types or qualities; and
recessing the liner to a surface of the one or more dielectric materials.
8. The method as recited in claim 7 , wherein the quasi-ALE process includes a plurality of gas and bias pulse cycles of depositing a polymer with embedded etchant and removing the polymer to release the etchant to remove the one or more dielectric materials.
9. The method as recited in claim 7 , wherein the quasi-ALE process etches isolation regions without fins slower than dense fin regions, and the plasma free reactive cleaning or remote plasma etch reversely etches the isolation regions faster than the dense fin regions.
10. The method as recited in claim 7 , wherein the isotropically etching includes a cyclic removal process.
11. The method as recited in claim 7 , further comprising a plasma strip to remove collected polymer from the quasi-ALE process.
12. The method as recited in claim 11 , wherein the plasma strip includes N 2 H 2 or O 2 plasma.
13. The method as recited in claim 7 , wherein the liner includes silicon nitride and recessing the liner includes etching the liner with hot phosphoric acid.
14. A method for uniform fin reveal depth for semiconductor devices, comprising:
dry etching a dielectric material to reveal semiconductor fins by a quasi-atomic layer etching (quasi-ALE) process to achieve depth uniformity across different fin pitches wherein the quasi-ALE process laterally etches isolation regions without fins slower than dense fin regions, and the isotropically etching reversely laterally etches the isolation regions faster than the dense fin regions; and
compensating for a lateral bias induced by the quasi-ALE process by isotropically etching the dielectric material.
15. The method as recited in claim 14 , wherein the quasi-ALE process includes a plurality of gas and bias pulse cycles of depositing a polymer with embedded etchant and removing the polymer to release the etchant to remove the dielectric material.
16. The method as recited in claim 14 , wherein isotropically etching includes a plasma free reactive cleaning or remote plasma etch.