Electroplating in presence of co2
OwnerTakabumi Nagai, Kazuhisa Fujii +1inventors
InventorsTakabumi Nagai, Kazuhisa Fujii, Hideaki Asai
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Abstract
The present invention provides a method for conducting electroplating in the presence of CO2 and a metal salt-containing aqueous solution, wherein the CO2 is in the form of liquid, subcritical or supercritical, the method being characterized in that a nonionic compound having a CO2-affinitive moiety is further added to the system where the aqueous solution and CO2 coexist. The method of the present invention improves the efficiency of the electrochemical reaction process and enables formation of an excellent metal film.
Claims19
A method for conducting electroplating in the presence of CO2 and a metal salt-containing aqueous solution, the CO2 being liquid, subcritical or supercritical, the method further comprising a step of adding a nonionic compound having a CO2-affinitive moiety to a system wherein the aqueous solution and CO2 coexist, the CO2-affinitive moiety being at least one member selected from the group consisting of:
- (1) homopolymers, bicopolymers and tricopolymers of polyoxypropylene, polyoxybutylene and/or polyoxyethylene;
- (2) fluorine-containing alkyl groups in which some or all of the hydrogen atoms are substituted by fluorine;
- (3) fluorine-containing polyether groups in which some or all of the hydrogen atoms are substituted by fluorine;
- and
- (4) dialkylsiloxy groups.
A plating bath comprising a metal salt-containing aqueous solution, CO2, and a nonionic compound having a CO2-affinitive moiety, the CO2 being liquid, subcritical or supercritical, the CO2-affinitive moiety being at least one member selected from the group consisting of:
- (1) homopolymers, bicopolymers and tricopolymers of polyoxypropylene, polyoxybutylene and/or polyoxyethylene;
- (2) fluorine-containing alkyl groups in which some or all of the hydrogen atoms are substituted by fluorine;
- (3) fluorine-containing polyether groups in which some or all of the hydrogen atoms are substituted by fluorine;
- and
- (4) dialkylsiloxy groups.
An additive for use in electroplating conducted in the presence of liquid, subcritical or supercritical CO2, the additive comprising a nonionic compound having a CO2-affinitive moiety,
- the CO2-affinitive moiety being at least one member selected from the group consisting of:
- (1) homopolymers, bicopolymers and tricopolymers of polyoxypropylene, polyoxybutylene and/or polyoxyethylene;
- (2) fluorine-containing alkyl groups in which some or all of the hydrogen atoms are substituted by fluorine;
- (3) fluorine-containing polyether groups in which some or all of the hydrogen atoms are substituted by fluorine;
- and
- (4) dialkylsiloxy groups.
A method for preprocessing conducted before plating comprising the step of degreasing and washing a plating substrate prior to plating using a nonionic compound having a CO2-affinitive moiety,
- the CO2-affinitive moiety being at least one member selected from the group consisting of:
- (1) homopolymers, bicopolymers and tricopolymers of polyoxypropylene, polyoxybutylene and/or polyoxyethylene;
- (2) fluorine-containing alkyl groups in which some or all of the hydrogen atoms are substituted by fluorine;
- (3) fluorine-containing polyether groups in which some or all of the hydrogen atoms are substituted by fluorine;
- and
- (4) dialkylsiloxy groups.
A method for postprocessing conducted after plating comprising the step of washing a plated film after plating using a nonionic compound having a CO2-affinitive moiety, the CO2-affinitive moiety being at least one member selected from the group consisting of:
- (1) homopolymers, bicopolymers and tricopolymers of polyoxypropylene, polyoxybutylene and/or polyoxyethylene;
- (2) fluorine-containing alkyl groups in which some or all of the hydrogen atoms are substituted by fluorine;
- (3) fluorine-containing polyether groups in which some or all of the hydrogen atoms are substituted by fluorine;
- and
- (4) dialkylsiloxy groups.
A plated film having
- (1) per cm2, not more than one pinhole having a diameter of at least 1 μm;
- (2) a film thickness of not more than 1 μm;
- and
- (3) a plated film surface roughness of not greater than 10 nm.
Dependencies are inferred from the claim text.