Fluorocarbon molecules for high aspect ratio oxide etch
Etching gases are disclosed for plasma etching channel holes, gate trenches, staircase contacts, capacitor holes, contact holes, etc., in Si-containing layers on a substrate and plasma etching methods of using the same. The etching gases are trans-1,1,1,4,4,4-hexafluoro-2-butene; cis-1,1,1,4,4,4-hexafluoro-2-butene; hexafluoroisobutene; hexafluorocyclobutane (trans-1,1,2,2,3,4); pentafluorocyclobutane (1,1,2,2,3-); tetrafluorocyclobutane (1,1,2,2-); or hexafluorocyclobutane (cis-1,1,2,2,3,4). The etching gases may provide improved selectivity between the Si-containing layers and mask material, less damage to channel region, a straight vertical profile, and reduced bowing in pattern high aspect ratio structures.
1. A method of depositing a polymer layer, the method comprising plasma activating a fluorocarbon molecule to form the polymer layer, the fluorocarbon molecule selected from the group consisting of hexafluoroisobutene; pentafluorocyclobutane (1,1,2,2,3-); and tetrafluorocyclobutane (1,1,2,2-); and wherein the polymer layer forms a protection layer on sidewalls of a pattern etch structure.
2. The method of claim 1 , the method further comprising no addition of oxygen.
3. The method of claim 1 , wherein the pattern etch structure has an aspect ratio ranging from 2.5:1 to 100:1.
4. The method of claim 3 , wherein the pattern etch structure has an aspect ratio ranging from 10:1 to 100:1.
5. The method of claim 1 , wherein the polymer layer prevents ions and radicals from etching the sidewalls.
6. The method of claim 5 , wherein the polymer layer results in a pattern etch structure having a vertical profile that is straight with no bowing.
7. A method of producing a pattern etch structure, the method comprising plasma activating a fluorocarbon molecule to form a polymer layer on a sidewall of the pattern etch structure, the fluorocarbon molecule selected from the group consisting of hexafluoroisobutene; pentafluorocyclobutane (1,1,2,2,3-); tetrafluorocyclobutane (1,1,2,2-).
8. The method of claim 7 , the method further comprising no addition of oxygen.
9. The method of claim 7 , wherein the pattern etch structure has an aspect ratio ranging from 2.5:1 to 100:1.
10. The method of claim 9 , wherein the pattern etch structure has an aspect ratio ranging from 10:1 to 100:1.
11. The method of claim 7 , the method further comprising the polymer layer preventing ions and radicals from etching the sidewalls.
12. The method of claim 11 , the pattern etch structure produced having a vertical profile that is straight with no bowing.