US 2006/0188659 A1 · Cobalt self-initiated electroless via fill for stacked memory cells

Abstract

A method for electrolessly filling a stacked memory cell interconnect feature comprising electroless deposition from a composition comprising Co ions and a reducing agent by bottom-up filling initiated by reduction to Co metal on an electrically conducting bottom of the feature. An electroless deposition composition for electrolessly depositing Co in a high aspect ratio stacked memory cell interconnect feature, the composition comprising water, Co ions, a complexing agent, a buffering agent, a borane-based reducing agent component, and a hypophosphite reducing agent component. There is a concentration ratio of borane-based reducing agent to hypophosphite reducing agent of less than about 0.5.

Claims21

Dependent claims

A method for electrolessly filling a stacked memory cell interconnect feature, the method comprising:

contacting the stacked memory cell interconnect feature with an electroless deposition composition comprising a source of Co ions and a reducing agent, wherein the stacked memory interconnect feature has an electrically conducting bottom, side walls having a dielectric surface, and a height-to-width aspect ratio of at least about 2, whereby a portion of the Co ions are reduced to Co metal on the electrically conducting bottom, and bottom-up filling of the stacked memory interconnect feature is achieved by continued reduction of Co ions.

A method for electrolessly filling a stacked memory cell interconnect feature, the method comprising:

contacting the stacked memory cell interconnect feature with an electroless deposition composition comprising a source of Co ions and a reducing agent, wherein the stacked memory interconnect feature has an electrically conducting bottom, side walls having a dielectric surface, and a height-to-width aspect ratio of at least about 10, whereby a portion of the Co ions are reduced to Co metal on the electrically conducting bottom, and bottom-up filling of the stacked memory interconnect feature is achieved by continued reduction of Co ions, wherein the electroless deposition composition comprises:
water;
a source of Co ions;
a complexing agent;
a buffering agent;
a borane-based reducing agent component selected from the group consisting of an alkali metal borohydride, dimethylamine borane, diethylamine borane, morpholine borane, and mixtures thereof;
and
a hypophosphite reducing agent component selected from the group consisting of an alkali metal hypophosphite, ammonium hypophosphite, hypophosphorous acid, and mixtures thereof;
and
wherein the borane-based reducing agent component is present in a borane-based reducing agent component concentration, and the hypophosphite reducing agent component is present in a hypophosphite reducing agent component concentration, and the borane-based reducing agent component concentration and the hypophosphite reducing agent component concentration are selected to yield a concentration ratio of borane-based reducing agent component concentration in g/L to hypophosphite reducing agent component concentration in g/L which is less than about 0.5.

7 more elements

An electroless deposition composition for electrolessly depositing Co in a high aspect ratio stacked memory cell interconnect feature, the composition comprising:

water;
a source of Co ions;
a complexing agent;
a buffering agent;
a borane-based reducing agent component;
and
a hypophosphite reducing agent component;
wherein the borane-based reducing agent component is selected from the group consisting of an alkali metal borohydride, dimethylamine borane, diethylamine borane, morpholine borane, and mixtures thereof;
wherein the hypophosphite reducing agent component is selected from the group consisting of an alkali metal hypophosphite, ammonium hypophosphite, hypophosphorous acid, and mixtures thereof;
and
wherein the borane-based reducing agent component is present in a borane-based reducing agent component concentration, and the hypophosphite reducing agent component is present in a hypophosphite reducing agent component concentration, and the borane-based reducing agent component concentration and the hypophosphite reducing agent component concentration are selected to yield a concentration ratio of borane-based reducing agent component concentration in g/L to hypophosphite reducing agent component concentration in g/L which is less than about 0.5.

8 more elements

Dependencies are inferred from the claim text.

Cobalt self-initiated electroless via fill for stacked memory cells

Life of this patent

Cobalt self-initiated electroless via fill for stacked memory cells

Life of this patent

Abstract

Claims21