Etching method using oxygen-containing hydrofluorocarbon
An etching method for forming an aperture by selectively etching one or more silicon-containing films in a substrate using a patterned mask layer deposited on top of the one or more silicon-containing films comprises: mounting the substrate in a processing chamber; introducing an etching gas containing a vapor of an oxygen-containing hydrofluorocarbon into the processing chamber; converting the etching gas to a plasma; and allowing an etching reaction to proceed between the plasma and the one or more silicon-containing films so that the one or more silicon-containing films are selectively etched versus the patterned mask layer to form the aperture, wherein the oxygen-containing hydrofluorocarbon has a general formula C x H y F z O n , where 2≤x≤13, 1≤y≤15, 1≤z≤21, 1≤n≤3.
1 . An etching method for forming an aperture by selectively etching one or more silicon-containing films in a substrate using a patterned mask layer deposited on top of the one or more silicon-containing films, the method comprising:
mounting the substrate in a processing chamber;
introducing an etching gas containing a vapor of an oxygen-containing hydrofluorocarbon into the processing chamber;
converting the etching gas to a plasma; and
allowing an etching reaction to proceed between the plasma and the one or more silicon-containing films so that the one or more silicon-containing films are selectively etched versus the patterned mask layer to form the aperture,
wherein the oxygen-containing hydrofluorocarbon has a general formula C x H y F z O n , where 2≤x≤13, 1≤y≤15, 1≤z≤21, 1≤n≤3, provided that when x=4, y≠3, z≠7 and n≠1,
wherein the oxygen-containing hydrofluorocarbon has at least one ether group represented by one of following formulas:
wherein R 1 is H, F, C x H 2x+2−z F z or C x F 2x+2 ; R 2 is H, C x H 2x+2−z F z or C x F 2x+2 ; R 3 is F, C x H 2x+2−z F z or C x F 2x+2 , where 2≤x≤3 and 1≤z≤3.
2 . The method of claim 1 , wherein the oxygen-containing hydrofluorocarbon contains at least one oxygen atom in an ether group or in a carbonyl group.
3 . The method of claim 1 , wherein the oxygen-containing hydrofluorocarbon is selected from C 4 H 2 F 6 O 2 , C 3 H 2 F 6 O, C 2 H 2 F 4 O, C 2 HF 3 O, C 3 H 5 F 3 O, C 2 H 4 F 2 O, C 5 H 4 F 8 O, C 5 HF 11 O, C 2 H 3 F 3 O, or their isomers.
4 . The method of claim 1 , wherein the oxygen-containing hydrofluorocarbon is C 3 H 2 F 6 O or its isomers.
5 . The method of claim 1 , wherein the oxygen-containing hydrofluorocarbon is C 3 H 2 F 6 O (CAS No: 57041-67-5).
6 . The method of claim 1 , wherein the oxygen-containing hydrofluorocarbon is C 3 H 2 F 6 O (CAS No: 84011-06-3).
7 . The method of claim 1 , wherein the oxygen-containing hydrofluorocarbon is C 3 H 2 F 6 O (CAS No: 920-66-1).
8 . The method of claim 1 , wherein the etching gas further includes a vapor of a fluorocarbon or hydrofluorocarbon selected from CF 4 , C 2 F 6 , C 3 F 6 , C 4 F 6 , C 4 F 8 , C 5 F 8 , C 5 F 10 , C 6 F 12 , C 7 F 14 , C 8 F 16 , CH 2 F 2 , CH 3 F, CHF 3 , C 5 HF 7 , C 3 H 2 F 6 , C 3 H 4 F 2 , C 3 F 2 H 4 , C 4 H 2 F 6 , C 4 H 3 F 7 , C 3 HF 4 N, CF 3 I, C 3 F 7 I, C 4 F 9 I, C 4 H 9 F 3 Si, C 5 H 9 F 5 Si or combinations thereof.
9 . The method of claim 1 , wherein the etching gas further includes an oxidizing gas selected from O 2 , O 3 , CO, CO 2 , SO, SO 2 , FNO, N 2 , NO, N 2 O, NO 2 , H 2 O, COS or combinations thereof.
10 . The method of claim 1 , wherein the etching gas further includes an inert gas selected from He, Ar, Xe, Kr or Ne.
11 . The method of claim 10 , wherein a selectivity of the silicon oxide film versus the silicon nitride film in the layer of ONON films ranges from 1:5 to 5:1.
12 . The method of claim 1 , wherein the etching gas further includes an additional gas selected from H 2 , SF 6 , NF 3 , N 2 , NH 3 , Cl 2 , BCl 3 , Br 2 , F 2 , HBr, HCl, PF 3 or combinations thereof.
13 . The method of claim 1 , wherein an aspect ratio of the aperture is above 5.
14 . The method of claim 1 , wherein the one or more silicon-containing films comprise a layer of Si a O b H c C d N e , where a >0, b, c, d and e≥0, selected from silicon oxide, silicon nitride, crystalline Si, poly-silicon, amorphous silicon, low-k SiCOH, SiOCN, SiC, SiON, or a layer of alternating silicon oxide and silicon nitride (ONON) films or alternating silicon oxide and poly-silicon (OPOP) films.
15 . An etching method for forming an aperture by selectively etching a silicon-containing film in a substrate using a patterned mask layer deposited on top of the silicon oxide film or the, the method comprising:
mounting the substrate in a processing chamber;
introducing an etching gas containing an oxygen-containing
hydrofluorocarbon C 3 H 2 F 6 O vapor into the processing chamber;
converting the etching gas to a plasma; and
allowing an etching reaction to proceed between the plasma and the silicon-containing film so that the silicon-containing film is selectively etched versus the patterned mask layer to form the aperture.
16 . The method of claim 15 , wherein the oxygen-containing hydrofluorocarbon is C 3 H 2 F 6 O or its isomers.
17 . The method of claim 15 , wherein the oxygen-containing hydrofluorocarbon is C 3 H 2 F 6 O (CAS No: 57041-67-5).
18 . The method of claim 15 , wherein the oxygen-containing hydrofluorocarbon is C 3 H 2 F 6 O (CAS No: 84011-06-3).
19 . The method of claim 15 , wherein the oxygen-containing hydrofluorocarbon is C 3 H 2 F 6 O (CAS No: 920-66-1).
20 . The method of claim 15 , wherein the etching gas further includes a vapor of a fluorocarbon or hydrofluorocarbon selected from CF 4 , C 2 F 6 , C 3 F 6 , C 4 F 6 , C 4 F 8 , C 5 F 8 , C 5 F 10 , C 6 F 12 , C 7 F 14 , C 8 F 16 , CH 2 F 2 , CH 3 F, CHF 3 , CHF 7 , C 3 H 2 F 6 , C 3 H 4 F 2 , C 3 F 2 H 4 , C 4 H 2 F 6 , C 4 H 3 F 7 , C 3 HF 4 N, CF 3 I, C 3 F 7 I, C 4 FoI, C 4 H 9 F 3 Si, C 5 H 9 F 5 Si or combinations thereof.
21 . The method of claim 15 , wherein the etching gas further includes an oxidizing gas selected from O 2 , O 3 , CO, CO 2 , SO, SO 2 , FNO, N 2 , NO, N 2 O, NO 2 , H 2 O, COS or combinations thereof.
22 . The method of claim 15 , wherein the etching gas further includes an inert gas selected from He, Ar, Xe, Kr or Ne.
23 . The method of claim 15 , wherein the etching gas further includes an additional gas selected from H 2 , SF 6 , NF 3 , N 2 , NH 3 , Cl 2 , BCl 3 , Br 2 , F 2 , HBr, HCl, PF 3 or combinations thereof.
24 . The method of claim 15 , wherein an aspect ratio of the aperture is above 5.
25 . The method of claim 15 , wherein the silicon-containing film is a silicon oxide film, or a silicon nitride film.