Removing a sacrificial material via sublimation in forming a semiconductor
View Patent ↗The present disclosure includes apparatuses and methods related to sublimation in forming a semiconductor. In an example, a method may include forming a sacrificial material in an opening of a structure, wherein the sacrificial material displaces a solvent used in a wet clean operation and removing the sacrificial material via sublimation by exposing the sacrificial material to sub-atmospheric pressure.
1. A method for forming a semiconductor device, comprising:
performing a wet clean operation on a structure in an inert atmosphere;
displacing a solvent used in the wet clean operation in an opening of the structure with a sacrificial material without exposing the structure to gas;
exposing the structure with the sacrificial material to oxygen;
decomposing the sacrificial material from a solid to a gas via sublimation by exposing the sacrificial material to sub-atmospheric pressure; and
removing the gas via a gas purge.
2. The method of claim 1 , wherein the sacrificial material is formed in the opening of the structure in response to performing the wet clean operation.
3. The method of claim 1 , wherein forming the sacrificial material obstructs the opening in the structure.
4. The method of claim 1 , wherein the solvent is isopropyl alcohol (IPA).
5. The method of claim 1 , wherein the sacrificial material is exposed to sub-atmospheric pressure via a pump.
6. The method of claim 1 , wherein the sacrificial material is spin coated into the opening of the structure.
7. The method of claim 1 , wherein the sacrificial material prevents pattern collapse while the structure dries.
8. The method of claim 1 , wherein the sacrificial material is exposed to sub-atmospheric pressure via a vacuum.
9. The method of claim 1 , further comprising heating the structure to accelerate the sublimation.
10. The method of claim 1 , further including removing the sacrificial material via sublimation by heating the structure.
11. The method of claim 10 , wherein the sacrificial material thermally decomposes into a gaseous product without melting.
12. The method of claim 10 , wherein heating the structure is done using a temperature control.
13. The method of claim 12 , wherein the temperature control can include a gas purge to remove gaseous byproducts.
14. The method of claim 12 , wherein the temperature control can include a gas purge to protect the structure from oxidation.
15. The method of claim 12 , wherein the temperature control can be placed under a vacuum to remove gaseous byproducts.
16. The method of claim 10 , including using the solvent to wet clean the structure prior to forming the sacrificial material.
17. The method of claim 10 , including allowing the solvent to evaporate prior to removing the sacrificial material.
18. The method of claim 1 , further including forming the sacrificial material in the opening of the structure using a reactive gas; and
removing the sacrificial material via sublimation by removing the reactive gas from the structure.
19. The method of claim 18 , wherein the sacrificial material is ammonium formate and is formed using formic acid as the solution and ammonia as the reactive gas.
20. The method of claim 18 , wherein the sacrificial material is ammonium acetate and is formed using acetic acid as the solution and ammonia as the reactive gas.
21. The method of claim 18 , wherein the sacrificial material is ammonium carbamate and is formed using an ammonia (NH 3 ) solution and carbon dioxide (CO 2 ) as the reactive gas.
22. The method of claim 18 , wherein the sacrificial material decomposes into a gas mixture in response to removing the reactive gas from the structure.
23. The method of claim 18 , including heating the structure to accelerate sublimation.
24. The method of claim 18 , including allowing the solvent to evaporate in a carbon dioxide (CO 2 ) atmosphere.