Bond pad structure with stress-buffering layer capping interconnection metal layer

Claim 2

A bond pad structure, comprising: a first metal layer formed on an integrated circuit substrate; a passivation layer formed over said first metal layer and having at least one first opening that exposes at least part of said first metal layer; a first interposed, single-material layer, a stress-buffering, single-material layer, and a second interposed, single-material layer successively deposited along a bottom and sidewalls of said first opening; and a bond pad layer deposited over and directly contact the second interposed, single-material layer; wherein said stress-buffering, single-material layer has a property selected from the group consisting of Young's modulus, hardness, strength and toughness greater than that of at least one of said first metal layer and said bond pad layer, and is deposited directly on said first interposed, single-material layer along the bottom and sidewalls of said first openings; said first interposed, single-material layer serves as a metal-diffusion barrier layer directly on said first metal layer, and conformally lines said bottom and said sidewalls of said first opening; and said second interposed, single-material layer serves as a metal-diffusion barrier layer-directly on said stress-buffering, single-material layer.

Claim 3

The bond pad structure of claim 1 , wherein said stress-buffering, single-material layer comprises a tungsten layer.

Claim 4

The bond pad structure of claim 1 , wherein said first metal layer comprises copper or copper—based alloy.

Claim 5

The bond pad structure of claim 1 , wherein said bond pad layer comprises aluminum or aluminum—based alloy.

Claim 6

The bond pad structure of claim 1 , wherein said first interposed, single-material layer comprises TaN, TiN, Ta, TiW, or WN.

Claim 7

The bond pad structure of claim 1 , wherein said second interposed, single-material layer comprises TaN, TiN, Ta, TiW, or WN.

Claim 8

The bond pad structure of claim 1 , wherein said integrated circuit substrate comprises at least one dielectric layer having a dielectric constant less than about 3.9, and said first metal layer is formed in said dielectric layer.

Claim 9

The bond pad structure of claim 1 , wherein said integrated circuit substrate comprises an integrated circuit, and at least part of said integrated circuit is located under said bond pad structure.

Claim 10

The bond pad structure of claim 1 , wherein, said stress-buffering, single-material layer is formed in said first opening and at least located over said first metal layer; and wherein, said bond pad layer fills said first opening.

Claim 11

The bond pad structure of claim 1 , wherein, said passivation layer comprises at least one island region surrounded by said first opening; and wherein, said stress-buffering, single-material layer is formed overlying said passivation layer and fills said first opening.

Claim 12

The bond pad structure of claim 1 , wherein, said stress-buffering, single-material layer is formed over said first metal layer along said first opening; wherein, said stress-buffering, single-material layer comprises at least one second opening that is smaller than said first opening and exposes at least part of said first metal layer; and wherein, said bond pad layer is formed overlying said stress-buffering, single-material layer and fills said second opening.

Claim 13

The bond pad structure of claim 1 , further comprising: a second metal layer located under said first metal layer; a plurality of conductive via plugs located between said first metal layer and said second metal layer, and electrically connecting said first metal layer to said second metal layer; and a buffering layer located between said second metal layer and said plurality of conductive via plugs, wherein said buffering layer has a property selected from the group consisting of Young's modulus, hardness, strength and toughness greater than that of said second metal layer.

Claim 14

The bond pad structure of claim 12 , wherein said second metal layer comprises copper or copper-based alloy, and said buffering layer comprises a tungsten layer.

Claim 15

The bond pad structure of claim 1 , further comprising: a second metal layer located under said first metal layer; a plurality of conductive via plugs located between said first metal layer and said second metal layer, and electrically connecting said first metal layer to said second metal layer; and a buffering layer located between said first metal layer and said plurality of conductive via plugs, wherein said buffering layer has a property selected from the group consisting of Young's modulus, hardness, strength and toughness greater than that of said first metal layer.

Claim 16

The bond pad structure of claim 14 , wherein said second metal layer comprises copper or copper-based alloy, and said buffering layer comprises a tungsten layer.

Claim 17

A bond pad structure, comprising: a copper-based metal layer formed on an integrated circuit substrate; a passivation layer located over said copper-based metal layer and having at least one first opening that exposes at least part of said copper-based metal layer; a first interposed, single-material layer, a stress-buffering, single-material layer, and a second interposed, single-material layer successively deposited along a bottom and sidewalls of said first opening; and an aluminum-based bond pad layer located over and directly on said second interposed, single-material layer and electrically connected to said copper-based metal layer; wherein said first interposed, single-material layer serves as a metal-diffusion barrier layer directly on said copper-based metal layer, and conformally lines said bottom and said sidewalls of said first opening; said second interposed, single-material layer serving as a metal-diffusion barrier layer directly on said stress-buffering, single-material layer; and said stress-buffering, single-material layer has a Young's modulus greater than that of at least one of said aluminum-based bond pad layer and said copper-based metal layer, and is directly on said first interposed, single-material layer along the bottom and sidewalls of said first openings.

Claim 18

A bond pad structure, comprising: a copper-based metal layer formed on an integrated circuit substrate; a passivation layer located over said copper-based metal layer and having at least one first opening that exposes at least part of said copper-based metal layer; a first interposed, single-material layer, a stress-buffering, single-material layer, and a second interposed, single-material layer successively deposited along a bottom and sidewalls of said first opening; and an aluminum-based bond pad layer located over and directly on said second interposed, single-material layer and electrically connected to said copper-based metal layer; wherein said first interposed, single-material layer serves as a metal-diffusion barrier layer directly on said copper-based metal layer, and conformally lines said bottom and said sidewalls of said first opening; said second interposed, single-material layer serving as a metal-diffusion barrier layer directly on said stress-buffering, single-material layer; and said stress-buffering, single-material layer has a Young's modulus greater than that of at least one of said aluminum-based bond pad layer and said copper-based metal layer, and is directly on said first interposed, single-material layer along the bottom and sidewalls of said first openings.

Claim 19

The bond pad structure of claim 16 , wherein said stress-buffering, single-material layer comprises a tungsten layer.

Claim 20

The bond pad structure of claim 17 , wherein said stress-buffering, single-material layer has a thickness of from about 500 angstroms to about 5000 angstroms.

Claim 21

The bond pad structure of claim 16 , wherein said first interposed, single-material layer comprises TaN, TiN, Ta, TiW, or WN.

Claim 22

The bond pad structure of claim 16 , wherein said second interposed, single-material layer comprises TaN, TiN, Ta, TiW, or WN.

Claim 23

The bond pad structure of claim 16 , wherein said integrated circuit substrate comprises at least one dielectric layer having a dielectric constant less than about 3.9, and said copper-based metal layer is formed in said dielectric layer.

Claim 24

The bond pad structure of claim 21 , wherein said integrated circuit substrate comprises an integrated circuit, and at least part of said integrated circuit is located under said bond pad structure.

Claim 25

The bond pad structure of claim 16 , wherein said passivation layer comprises at least one island region surrounded by said first opening, and said stress-buffering, single-material layer fills said first opening.

Claim 26

The bond pad structure of claim 16 , wherein said stress-buffering, single-material layer has at least one second opening that is smaller than said first opening and exposes at least part of said first metal layer, and said aluminum-based bond pad layer fills said second opening.

Claim 27

A bond pad structure, comprising: a copper-based metal layer located over an integrated circuit substrate; a passivation layer located over said copper-based metal layer and having at least one first opening that exposes at least part of said copper-based metal layer; a first interposed, single-material layer lining said bottom and said sidewalls of said first opening of said passivation layer and directly on said exposed copper-based metal layer; a tungsten layer formed directly on said first interposed layer in said first opening, conformally along the bottom and sidewalls of said first openings; a second interposed, single-material layer formed directly on said tungsten layer; and an aluminum-based bond pad layer formed directly on said second interposed, single-material layer and electrically connected to said copper-based metal layer.

Claim 28

A bond pad structure, comprising: a copper-based metal layer located over an integrated circuit substrate; a passivation layer located over said copper-based metal layer and having at least one first opening that exposes at least part of said copper-based metal layer; a first interposed, single-material layer lining said bottom and said sidewalls of said first opening of said passivation layer and directly on said exposed copper-based metal layer; a tungsten layer formed directly on said first interposed layer in said first opening, conformally along the bottom and sidewalls of said first openings; a second interposed, single-material layer formed directly on said tungsten layer; and an aluminum-based bond pad layer formed directly on said second interposed, single-material layer and electrically connected to said copper-based metal layer.

Claim 29

The bond pad structure of claim 25 , wherein said tungsten layer has a thickness of from about 500 angstroms to about 1500 angstroms, and said aluminum-based bond pad layer has a thickness of from about 6500 angstroms to about 7500 angstroms.

Claim 30

The bond pad structure of claim 25 , wherein said first interposed, single-material layer comprises TaN, TiN, Ta, TiW, or WN.

Claim 31

The bond pad structure of claim 25 , wherein said second interposed, single-material layer comprises TaN, TiN, Ta, TiW, or WN.

Claim 32

The bond pad structure of claim 25 , wherein said integrated circuit substrate comprises at least one dielectric layer having a dielectric constant less than about 3.9, and said copper-based metal layer is formed in said dielectric layer.

Claim 33

The bond pad structure of claim 25 , wherein said integrated circuit substrate comprises an integrated circuit, and at least part of said integrated circuit is located under said bond pad structure.

Claim 34

The bond pad structure of claim 25 , wherein said passivation layer comprises at least one island region surrounded by said first opening, and said tungsten layer fills said first opening.

Claim 35

The bond pad structure of claim 25 , wherein said tungsten layer comprises at least one second opening that is smaller than said first opening and penetrates said second interposed, single-material layer and said first interposed, single-material layer to expose at least part of said copper-based metal layer, and said aluminum-based bond pad layer fills said second opening.