Method for a chemical vapor deposition of copper on an ion prepared conductive surface

Claim 3

A method as in claim 1 in which the inert gas is selected from the group consisting of Ar, He, Ne, Kr, H 2 , N 2 , and Xe.

Claim 4

A method as in claim 1 in which step a) includes source ions having an energy level of generally less than 500 eV, whereby the low energy of the ions minimizes the penetration of ions into the exposed Cu-receiving surface.

Claim 5

A method as in claim 1 in which step a) includes source ions having an energy level of generally less than 150 eV, whereby the low energy of the ions minimizes the penetration of ions into the exposed Cu-receiving surface.

Claim 6

A method as in claim 1 in which step a) includes generating the source ions from a high density plasma source, having an ion density of greater than approximately 5 mA/cm 2 .

Claim 7

A method as in claim 5 in which the high density plasma source is selected from the group consisting of ECR, inductively coupled RF, TCP, and helicon plasma sources.

Claim 8

A method as in claim 1 in which step a) includes generating the source ions from an ion source having a density of less than approximately 5 mA/cm 2 .

Claim 9

A method as in claim 7 in which the low density source is selected from the group consisting of ion gun, RF sputter, and capacitively coupled substrate holder sources.

Claim 10

A method as in claim 1 in which the Cu-receiving surface is selected from the group consisting of Cu, Ti, W, and Al, whereby the cleaning of the Cu-receiving surface in step b) promotes adhesion and conductivity between the Cu-receiving surface and the deposited Cu.

Claim 11

A method as in claim 1 in which the Cu-receiving surface is selected from the group consisting of TiN, TiON, TiSiN, TaSiN, TaN, TiW, TiWN, Mo, and WN, whereby Cu is adhered to a Cu-receiving surface which acts as a conductive diffusion barrier between the deposited Cu and regions of the IC underlying the Cu-receiving surface.

Claim 12

A method as in claim 1 in which step a) includes exposing the Cu-receiving surface in a low pressure environment of less than approximately 10 mT, whereby the ion bombardment is anisotropic.

Claim 15

In an integrated circuit interlevel dielectric having a first surface including a conductive connection area with a connection area surface, a second surface overlying the first surface, and a via, having vertical walls between the second surface and the first surface connection area surface, a method of enhancing conductivity between a via interconnect, formed from the chemical vapor deposition (CVD) of copper, and the first surface connection area, the method comprising the steps of: a) depositing diffusion barrier material in the via to form a diffusion barrier surface adjoining the walls of the via and overlying the first surface connection area revealed by the via; b) etching the diffusion barrier surface overlying the first surface connection area, to reveal the first surface connection area surface; b 1 ) exposing the diffusion barrier surface adjoining the walls of the via to a reactive oxygen species to form a thin layer of oxygen-contained barrier material over the diffusion barrier surface, whereby the subsequently deposited Cu stud better adheres to the via walls: c) exposing the first surface connection area surface, revealed in step b), to a low energy anisotropic source of ions from an inert gas to clean contaminants from the first surface connection area, whereby the exposure of the conduction area to ions improves the electrical conductivity of the surface to subsequently deposited Cu; and d) applying CVD Cu in the via to form a highly conductive interconnect between the first surface connection area and the second surface.

Claim 16

In an integrated circuit interlevel dielectric having a first surface including a conductive connection area with a connection area surface, a second surface overlying the first surface, and a via, having vertical walls between the second surface and the first surface connection area surface, a method of enhancing conductivity between a via interconnect, formed from the chemical vapor deposition (CVD) of copper, and the first surface connection area, the method comprising the steps of: a) depositing diffusion barrier material in the via to form a diffusion barrier surface adjoining the walls of the via and overlying the first surface connection area revealed by the via; b) etching the diffusion barrier surface overlying the first surface connection area, to reveal the first surface connection area surface; b 1 ) exposing the diffusion barrier surface adjoining the walls of the via to a reactive oxygen species to form a thin layer of oxygen-contained barrier material over the diffusion barrier surface, whereby the subsequently deposited Cu stud better adheres to the via walls: c) exposing the first surface connection area surface, revealed in step b), to a low energy anisotropic source of ions from an inert gas to clean contaminants from the first surface connection area, whereby the exposure of the conduction area to ions improves the electrical conductivity of the surface to subsequently deposited Cu; and d) applying CVD Cu in the via to form a highly conductive interconnect between the first surface connection area and the second surface.

Claim 17

A method as in claim 13 in which step c) is performed in a low pressure environment of less than approximately 10 mT, whereby the ions anisotropically clean the connection area surface while removing a minimal amount of oxygen-contained barrier material from the via walls.

Claim 18

A method as in claim 13 in which step b) includes using an oxygen ion source to etch the diffusion barrier surface in the via overlying the connection area surface, whereby steps b) and b 1 ) are substantially combined.

Claim 19

A method as in claim 13 in which step b) includes using an inert gas ion source to etch the diffusion barrier surface in the via overlying the connection area surface, whereby steps b) and c) are substantially combined.

Claim 20

In an integrated circuit interlevel dielectric having a first surface including a semiconductor connection area with a connection area surface, a second surface overlying the first surface, and a via, having vertical walls between the second surface and the connection area surface, a method of enhancing the conductivity between a via interconnect, formed from the chemical vapor deposition (CVD) of copper, to the first surface connection area, the method comprising the steps of: a) depositing diffusion barrier material in the via to form a diffusion barrier surface adjoining the walls of the via and overlying the first surface connection area revealed by the via; b) exposing the diffusion barrier surface in the via to a source of ions from an inert gas and oxygen; b 1 ) cleaning contaminants from the diffusion barrier surface in response to the inert gas ion exposure in step b), whereby the electrical conductivity between the ion-exposed diffusion barrier surface and a subsequently deposited Cu stud is improved; b 2 ) simultaneously with Step b 1 ), forming a thin layer of oxide on the diffusion barrier surface with the ions of oxygen; and b 3 ) stopping the exposure of the diffusion barrier surface in step a) before an oxide layer is formed in step b 2 ) that exceeds approximately 30 Å; and c) applying CVD Cu in the via so that the copper stud adheres to the diffusion barrier, electrically interfacing the first surface connection area to the second surface.

Claim 21

In an integrated circuit interlevel dielectric having a first surface including a semiconductor connection area with a connection area surface, a second surface overlying the first surface, and a via, having vertical walls between the second surface and the connection area surface, a method of enhancing the conductivity between a via interconnect, formed from the chemical vapor deposition (CVD) of copper, to the first surface connection area, the method comprising the steps of: a) depositing diffusion barrier material in the via to form a diffusion barrier surface adjoining the walls of the via and overlying the first surface connection area revealed by the via; b) exposing the diffusion barrier surface in the via to a source of ions from an inert gas and oxygen; b 1 ) cleaning contaminants from the diffusion barrier surface in response to the inert gas ion exposure in step b), whereby the electrical conductivity between the ion-exposed diffusion barrier surface and a subsequently deposited Cu stud is improved; b 2 ) simultaneously with Step b 1 ), forming a thin layer of oxide on the diffusion barrier surface with the ions of oxygen; and b 3 ) stopping the exposure of the diffusion barrier surface in step a) before an oxide layer is formed in step b 2 ) that exceeds approximately 30 Å; and c) applying CVD Cu in the via so that the copper stud adheres to the diffusion barrier, electrically interfacing the first surface connection area to the second surface.

Claim 22

A method as in claim 17 in which the diffusion barrier material is selected from the group consisting of TiN, TiON, TiSiN, TaSiN, TaN, TiW, TiWN, Mo, and WN.

Claim 23

A method as in claim 17 in which step b) includes using a low energy ion source of less than approximately 150 eV, whereby cleaning with low energy ions promotes a smooth diffusion barrier surface and minimizes the possibility of inadvertently removing portions of the diffusion barrier surface.