Copper electroplating method

Patent metadata

Field	Value
Publication number	US-2016258077-A1
Application number	US-201415031317-A
Country	US
Kind code	A1
Filing date	Oct 9, 2014
Priority date	Oct 22, 2013
Publication date	Sep 8, 2016
Grant date	—

Abstract

The method for copper electroplating according to the present invention comprises an aqueous acidic copper plating bath containing a leveler additive which forms copper trenches having a cross-sectional round shape under direct current plating conditions, and at least one reverse current pulse cycle consisting of one forward current pulse and one reverse current pulse wherein the fraction of the reverse charge to the forward charge applied to the substrate in said at least one current pulse cycle ranges between 0.1 to 5%. The method is particularly suitable for simultaneously filling blind micro vias and plating trenches with a rectangular cross-sectional shape.

First claim

1 . A method for copper electroplating comprising, in this order, the steps of
(i) providing a substrate comprising blind micro vias and a patterned resist layer having openings for trench formation and an aqueous acidic copper electrolyte comprising a leveler additive wherein the leveler additive is selected from the group consisting of ureylene polymers, aminocarboxylic acids functionalized with polyalkylene glycol residues, aminocarboxylic acids functionalized with polyalkylene imine residues, aminocarboxylic acids functionalized with polyvinyl alcohol residues, peptides functionalized with polyalkylene glycol residues, peptides functionalized with polyalkylene imine residues and peptides functionalized with polyvinyl alcohol residues, (ii) operating said substrate as a cathode which is in contact with at least one anode and contacting said substrate with said aqueous acidic copper electrolyte, and, (iii) applying to the substrate an electrical current, comprising at least one current pulse cycle consisting of one forward current pulse and one reverse current pulse and wherein the fraction of reverse charge to the forward charge applied to said substrate in said at least one current pulse cycle ranges from 0.1 to 5%,
wherein
the duration of the forward current pulse in said at least one current pulse cycle ranges from 10 to 1000 ms,
the duration of the reverse current pulse in said at least one current pulse cycle ranges from 0.05 to 1 ms, and
the current density of the reverse current pulse in said at least one current cycle ranges from 20 to 100 A/dm 2 ,
wherein the applying fills the blind micro vias with copper and forms copper trenches having a rectangular cross-sectional shape.

2 . The method for copper electroplating according to claim 1 wherein the fraction of the reverse charge to the forward charge applied to the substrate in said at least one current pulse cycle ranges from 0.5 to 4%.

3 . The method for copper electroplating according to claim 1 wherein the fraction of the reverse charge to the forward charge applied to the substrate in said at least one current pulse cycle ranges from 1 to 3%.

4 . The method for copper electroplating according to claim 1 wherein the at least one anode is an inert anode.

5 . The method for copper electroplating according to claim 1 wherein the aqueous acidic copper electrolyte further comprises a metal ion redox system.

6 . The method for copper electroplating according to claim 5 wherein the metal ion redox system consists of ferrous and ferric ions.

7 . The method for copper electroplating according to claim 6 wherein the concentration of ferric ions ranges from 0.1 to 4.0 g/l.

8 . The method for copper electroplating according to claim 5 wherein the at least one anode is an inert anode.

9 . (canceled)

10 . The method for copper electroplating according to claim 1 wherein the concentration of the leveler additive ranges from 0.01 to 200 mg/l.

11 . (canceled)

12 . The method for copper electroplating according to claim 1 wherein the current density of the forward current pulse in said at least one current pulse cycle ranges from 0.5 to 10 A/dm 2 .

13 . (canceled)

14 . (canceled)

15 . The method for copper electroplating according to claim 2 wherein the fraction of the reverse charge to the forward charge applied to the substrate in said at least one current pulse cycle ranges from 1 to 3%.

16 . The method for copper electroplating according to claim 6 wherein the at least one anode is an inert anode.

17 . The method for copper electroplating according to claim 7 wherein the at least one anode is an inert anode.

18 . The method for copper electroplating according to claim 2 wherein the aqueous acidic copper electrolyte further comprises a metal ion redox system.

19 . The method for copper electroplating according to claim 3 wherein the aqueous acidic copper electrolyte further comprises a metal ion redox system.

20 . The method for copper electroplating according to claim 4 wherein the aqueous acidic copper electrolyte further comprises a metal ion redox system.

Assignees

• Atotech Deutschland Gmbh

Inventors

• Maciossek Andreas
• Mann Olivier
• Cebulla Pamela

Classifications

• C25D7/123

  Semiconductors first coated with a seed layer or a conductive layer · CPC title

• C25D17/10

  Electrodes {, e.g. composition, counter electrode} · CPC title

• C25D5/18 Primary

  Electroplating using modulated, pulsed or reversing current · CPC title

• C25D17/001

  Apparatus specially adapted for electrolytic coating of wafers, e.g. semiconductors or solar cells · CPC title

• C25D5/02 Primary

  Electroplating of selected surface areas · CPC title