Composition for cobalt plating comprising additive for void-free submicron feature filling
Described herein is a composition including metal ions consisting essentially of cobalt ions, and a specific monomeric and polymeric suppressing agent including a carboxylic, sulfonic, sulfinic, phosphonic, or phosphinic acid functional groups which show a suppressing effect that is required for void-free bottom-up filling of nanometer-sized recessed features.
1. A composition for cobalt electroplating consisting essentially of:
(a) cobalt ions,
(b) from 1 ppm to 1000 ppm, relative to a total weight of the composition, of a suppressing agent of formula S1
[B] n [A] p (S1)
or of formula S2
or of formula S3a or S3b
or of formula S4
Ø-R 1 (S4)
and their salts,
(c) boric acid,
(d) an inorganic or organic acid,
(e) optionally a wetting agent,
(f) optionally a leveling agent different from the suppressing agent, and
(g) water,
wherein
R 1 is selected from the group consisting of X 1 —CO—O—R 11 , X 1 —SO 2 —O—R 11 , X 1 —PR 11 O(OR 11 ), X 1 —P(OR 11 ) 2 , X 1 —PO(OR 11 ) 2 , and X 1 —SO—O—R 11 ;
R 2 , R 3 , R 4 are independently selected from the group consisting of R 1 and (i) H, (ii) aryl, (iii) C 1 to C 10 alkyl (iv) arylalkyl, (v) alkylaryl, and (vi) —(O—C 2 H 3 R 12 ) m —OH, wherein if one of R 2 , R 3 or R 4 are selected from the group consisting of R 1 , each other one of R 2 , R 3 or R 4 is different from R 1 ,
Ø is a C 6 to C 14 carbocyclic or a C 3 to C 10 nitrogen or oxygen containing heterocyclic aryl group, which may be unsubstituted or substituted by up to three C 1 to C 12 alkyl groups or up to two OH, NH 2 or NO 2 groups,
R 31 is selected from the group consisting of R 1 , H, OR 32 and R 32 ,
R 32 is selected from the group consisting of (i) H and (ii) C 1 to C 6 alkyl,
X 1 is a divalent group selected from the group consisting of (i) a chemical bond (ii) aryl, (iii) C 1 to C 12 alkanediyl, which may be interrupted by one or more O atoms, (iv) an arylalkyl group —X 12 —X 11 —, (v) an alkylaryl group —X 11 —X 12 —, and (vi) —(O—C 2 H 3 R 12 ) m O—,
X 2 is (i) a chemical bond or (ii) methanediyl,
R 11 is selected from the group consisting of H and C 1 to C 4 alkyl,
R 12 is selected from the group consisting of H and C 1 to C 4 alkyl,
X 12 is a divalent aryl group,
X 11 is a divalent C 1 to C 15 alkanediyl group,
A is a co-monomer selected from the group consisting of vinyl alcohol, which may optionally be (poly)ethyoxylated, acrylonitrile, styrene and acrylamide,
B is selected from the group consisting of formula Sla
n is an integer from 2 to 10 000,
m is an integer from 2 to 50,
o is an integer from 2 to 1 000, and
p is 0 or an integer from 1 to 10 000;
wherein the composition facilitates substantially void-free, bottom up filling of a recessed feature on a semiconductor substrate with cobalt, the recessed feature having an aperture size below 100 nm.
2. The composition according to claim 1 , wherein R 2 , R 3 and R 4 are selected from the group consisting of H, methyl, ethyl, and propyl.
3. The composition according to claim 1 , wherein R 2 and either R 3 or R 4 are selected from the group consisting of H, methyl, ethyl, and propyl, and the other group R 3 or R 4 is selected from the group consisting of R 1 .
4. The composition according to claim 1 , wherein R 3 and R 4 are selected from the group consisting of H, methyl, ethyl, and propyl, and R 2 is selected from the group consisting of R 1 .
5. The composition according to claim 1 , wherein R 11 is H.
6. The composition according to claim 1 , wherein n+p is an integer from 10 to 5000 and m is an integer from 2 to 30.
7. The composition according to claim 1 , wherein the suppressing agent is selected from the group consisting of polyacrylic acid, polyitaconic acid, a maleic acid acrylic acid copolymer, a methacrylic acid acrylic acid copolymer, an itaconic acid acrylic acid copolymer, polyvinylphosphonic acid, and polyvinylsulfonic acid.
8. The composition according to claim 1 , wherein the suppressing agent is selected from the group consisting of acrylic acid, itaconic acid, vinylphosphonic acid, phenylphosphinic acid, and vinylsulfonic acid.
9. The composition according to claim 1 , wherein R 1 is a sulfonate group and R 31 is OH.
10. The composition according to claim 1 , wherein the suppressing agent is selected from the group consisting of p-toluol sulfinate and p-toluol sulfonate.
11. The composition according to claim 1 , wherein the suppressing agent is present in an amount of from 20 to 1000 ppm, relative to the total weight of the composition.
12. The composition according to claim 1 , wherein the suppressing agent is present in an amount of from 30 to 1000 ppm, relative to the total weight of the composition.
13. The composition according to claim 1 , wherein the suppressing agent is a compound of formula S4a
wherein R 5 , R 6 , R 7 , R 8 , and R 9 are independently selected from the group consisting of (i) H and (ii) C 1 to C 6 alkyl.
14. The composition according to claim 13 , wherein R 5 , R 6 , R 7 , R 8 , and R 9 are independently selected from the group consisting of H, methyl, ethyl and propyl.
15. A method of using a compound of formula S1
[B] n [A] p (S1)
or of formula S2
or of formula S3a or S3b
or of formula S4
Ø-R 1 (S4)
and their salts,
the method comprising using the compound as a suppressing agent for void-free deposition of a metal comprising cobalt on a semiconductor substrate comprising recessed features having an aperture size below 100 nm,
wherein
R 1 is selected from the group consisting of X 1 —CO—O—R 11 , X 1 —SO 2 —O—R 11 , X 1 —PR 11 O(OR 11 ), X 1 —P(OR 11 ) 2 , X 1 —PO(OR 11 ) 2 , X 1 —SO—O—R 11 ;
R 2 , R 3 , R 4 are independently selected from the group consisting of R 1 and (i) H, (ii) aryl, (iii) C 1 to C 10 alkyl (iv) arylalkyl, (v) alkylaryl, and (vi) —(O—C 2 H 3 R 12 ) m —OH, wherein if one of R 2 , R 3 or R 4 are selected from the group consisting of R 1 , each other one of R 2 , R 3 or R 4 is different from R 1
Ø is a C 6 to C 14 carbocyclic or a C 3 to C 10 nitrogen or oxygen containing heterocyclic aryl group, which may be unsubstituted or substituted by up to three C 1 to C 12 alkyl groups or up to two OH, NH 2 or NO 2 groups,
R 31 is selected from the group consisting of R 1 , H, OR 32 and R 32 ,
R 32 is selected from the group consisting of (i) H and (ii) C 1 to C 6 alkyl,
X 1 is a divalent group selected from the group consisting of (i) a chemical bond (ii) aryl, (iii) C 1 to C 12 alkanediyl, which may be interrupted by O atoms, (iv) arylalkyl group —X 11 —X 12 —, (v) alkylaryl group —X 12 —X 11 —, and (vi) —(O—C 2 H 3 R 12 ) m O—,
X 2 is (i) a chemical bond or (ii) methanediyl,
R 11 is selected from the group consisting of H and C 1 to C 4 alkyl,
R 12 is selected from the group consisting of H and C 1 to C 4 alkyl,
X 12 is a divalent aryl group,
X 11 is a divalent C 1 to C 15 alkanediyl group,
A is a co-monomer selected from the group consisting of vinyl alcohol, which may optionally be (poly)ethyoxylated, acrylonitrile, styrene and acrylamide,
B is selected from the group consisting of formula Sla
n is an integer from 2 to 10 000,
m is an integer from 2 to 50,
o is an integer from 2 to 1 000, and
p is 0 or an integer from 1 to 10 000.
16. A process for depositing cobalt on a semiconductor substrate comprising a recessed feature having an aperture size below 100 nm the process comprising
(a) bringing a composition according to claim 1 into contact with the semiconductor substrate, and
(b) applying an electrical potential for a time sufficient to fill the recessed feature with cobalt.
17. The process according to claim 16 , wherein in step (b) a current density is ramped up from 0.1 mA/cm 2 up to 40 mA/cm 2 by applying an increasing rate that ranges from 5 μA/(cm 2 *s) to 400 μA/(cm 2 *s).
18. The process according to claim 16 , comprising a step (a1) comprising depositing a cobalt seed on a dielectric surface of the recessed feature before step (a).
19. The process according to claim 16 , wherein the recessed feature has an aperture size of 30 nm or below.