Method of etching semiconductor structures with etch gas

Patent metadata

Field	Value
Publication number	US-2016307764-A1
Application number	US-201414917424-A
Country	US
Kind code	A1
Filing date	Sep 9, 2014
Priority date	Sep 9, 2013
Publication date	Oct 20, 2016
Grant date	—

Abstract

Disclosed are sulfur-containing compounds 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 plasma etching compounds 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.

First claim

1 . A method for plasma etching a silicon-containing layer on a substrate, the method comprising,
introducing a vapor of a compound into a chamber containing the silicon-containing layer on a substrate, the compound having a formula selected from the group consisting of: R 1 —SH R 2 —S—R 3 C 2 F 4 S 2 (CAS 1717-50-6)
wherein R 1 , R 2 , and R 3 is each independently a saturated C1 to C4 alkyl or fluoroalkyl group and R 2 and R 3 may be joined to form a 5 or 6 member S-containing ring;
introducing an inert gas into the chamber;
generating a plasma to produce an activated vapor from the vapor; and
removing volatile by-product from the chamber, wherein the activated vapor selectively reacts with the silicon-containing layer to form the volatile by-product.

2 . The method of claim 1 , wherein the compound is C 2 F 4 S 2 (CAS 1717-50-6).

3 . The method of claim 1 , wherein the compound has the formula R 1 —SH.

4 . The method of claim 3 , wherein the compound is selected from the group consisting of F 3 CSH (CAS 1493-15-8), F 3 C—CF 2 —SH (CAS 1540-78-9), F 3 C—CH 2 —SH (CAS 1544-53-2), CHF 2 —CF 2 —SH (812-10-2), CF 3 —CF 2 —CH 2 —SH (CAS 677-57-6), and F 3 C—CH(SH)—CF 3 (CAS 1540-06-3).

5 . The method of claim 1 , wherein the compound has the formula R 2 —S—R 3 .

6 . The method of claim 5 , wherein the compound is selected from the group consisting of F 3 C—S—CF 3 (CAS 371-78-8), F 3 C—S—CHF 2 (CAS 371-72-2), F 3 C—CF 2 —S—CF 2 —CF 3 (CAS 155953-22-3), and F 3 C—CF 2 —CF 2 —S—CF 2 —CF 2 —CF 3 (CAS 356-63-8).

7 . The method of claim 5 , wherein R 2 and R 3 are joined to form a 5 to 6 member S-containing ring.

8 . The method of claim 7 , wherein the compound is selected from the group consisting of c(—S—CF 2 —CF 2 —CHF—CF 2 —)(CAS 1035804-79-5), c(—S—CF 2 —CHF—CHF—CF 2 -) (CAS 30835-84-8), c(—S—CF 2 —CF 2 —CF 2 —CF 2 —CF 2 -)(CAS 24345-52-6), c(—S—CFH—CF 2 —CF 2 —CFH-) (2 R, 5 R)(CAS 1507363-75-8), c(—S—CFH—CF 2 —CF 2 —CFH-)(2 R, 5 S)(CAS 1507363-76-9), and c(—S—CFH—CF 2 —CF 2 —CH 2 -)(CAS 1507363-77-0).

9 . The method of claim 1 , wherein the silicon-containing layer comprises a layer of silicon oxide, silicon nitride, polysilicon, or combinations thereof.

10 . The method of claim 1 , further comprising introducing an oxidizer into the chamber.

11 . The method of claim 10 , wherein the oxidizer is selected from the group consisting of O 2 , O 3 , CO, CO 2 , NO, N 2 O, NO 2 , and combinations thereof.

12 . The method of claim 1 , further comprising introducing an etching gas into the chamber, wherein the etching gas is selected from the group consisting of cC 5 F 8 , cC 4 F 8 , C 4 F 8 , C 4 F 6 , CF 4 , CH 3 F, CF 3 H, CH 2 F 2 , COS, CS 2 ; CF 3 I; C 2 F 3 1 ; C 2 F 5 I; SO 2 ; 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-); and hexafluorocyclobutane (cis-1,1,2,2,3,4).

13 . The method of claim 10 , wherein the oxidizer is O 2 .

14 . The method of claim 1 wherein the compound is F 3 C—CH 2 —SH (CAS 1544-53-2).

15 . The method of claim 1 , wherein the silicon-containing layer comprises a combination of silicon oxide and silicon nitride.

16 . The method of claim 15 wherein the compound is F 3 C—CH 2 —SH (CAS 1544-53-2).

17 . The method of claim 15 wherein the compound is C 2 F 4 S 2 (CAS 1717-50-6).

18 . A sulfur-containing plasma etch compound having the formula R 1 —SH and a purity between approximately 99.9% v/v and approximately 100.0% v/v.

19 . The sulfur-containing plasma etch compound of claim 18 , wherein the compound is selected from the group consisting of F 3 CSH (CAS 1493-15-8), F 3 C—CF 2 —SH (CAS 1540-78-9), F 3 C—CH 2 —SH (CAS 1544-53-2), CHF 2 —CF 2 —SH (812-10-2), CF 3 —CF 2 —CH 2 —SH (CAS 677-57-6), and F 3 C—CH(SH)—-CF 3 (CAS 1540-06-3).

20 . The sulfur-containing plasma etch compound of claim 18 , wherein the compound is F 3 C—CH 2 —SH (CAS 1544-53-2).

Assignees

• Air Liquide American

Inventors

• Gupta Rahul
• Pallem Venkateswara R
• Surla Vijay
• Anderson Curtis
• Stafford Nathan

Classifications

• H10P70/12

  by dry cleaning only (H10P70/52 takes precedence) · CPC title

• H10P50/695

  characterised by the process involved to create the mask, e.g. lift-off masks or sidewalls or to modify the mask · CPC title

• H10P50/283 Primary

  by chemical means · CPC title

• H10P50/268 Primary

  of silicon-containing layers · CPC title

• H10P50/246

  of Group III-V materials · CPC title