Method of improving copper pad adhesion

• US 7,026,721 B2
• Filed: 01/08/2001
• Issued: 04/11/2006
• Est. Priority Date: 11/18/1999
• Status: Expired due to Term

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Chen, Sheng-Hsiung
• Primary Examiner(s): Whitehead, Jr., Carl
• Assistant Examiner(s): Mitchell, James M.
• Application Number:
  US09/755,282
• Publication Number:
  US 20010016415A1
• Time in Patent Office: 1,919 Days
• Field of Search: 257/784, 257/734, 257/786, 257/781, 257/779, 257/758, 257/459, 257/773, 257/774, 438/653, 438/654, 438/666, 438/612
• US Class Current: 257/779
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05073 Single internal layer
• CPC Class Codes: H01L 2224/05187 Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2224/05557 comprising protrusions or indentations
• CPC Class Codes: H01L 2224/05558 conformal layer on a patterned surface
• CPC Class Codes: H01L 2224/05559 non conformal layer on a patterned surface
• CPC Class Codes: H01L 2224/05624 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/4807 of bonding interfaces, e.g. interlocking features
• CPC Class Codes: H01L 2224/48458 of the interface with the bonding area
• CPC Class Codes: H01L 2224/4847 the connecting portion on the bonding area of the semiconductor or solid-state body being a wedge bond
• CPC Class Codes: H01L 2224/48624 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48724 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48799 Principal constituent of the connecting portion of the wire connector being Copper (Cu)
• CPC Class Codes: H01L 2224/48824 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/859 involving monitoring, e.g. feedback loop
• CPC Class Codes: H01L 24/03 : Manufacturing methods
• CPC Class Codes: H01L 24/05 : of an individual bonding area
• CPC Class Codes: H01L 24/11 : Manufacturing methods for bumps on insulating substrates H01L21/4853
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00011 : Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/00015 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed as prior art
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01007 : Nitrogen [N]
• CPC Class Codes: H01L 2924/01012 : Magnesium [Mg]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01024 : Chromium [Cr]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01073 : Tantalum [Ta]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/04941 : TiN
• CPC Class Codes: H01L 2924/04953 : TaN
• CPC Class Codes: H01L 2924/05042 : Si3N4
• CPC Class Codes: H01L 2924/10253 : Silicon [Si]
• CPC Class Codes: H01L 2924/13091 : Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/20753 : larger or equal to 30 microns less than 40 microns
• CPC Class Codes: H01L 2924/351 : Thermal stress

Abstract

This invention relates to a new improved method and structure in the fabricating of aluminum metal pads. The formation special aluminum bond pad metal structures are described which improve adhesion between the tantalum nitride pad barrier layer and the underlying copper pad metallurgy by a special interlocking bond pad structure. It is the object of the present invention to provide a process wherein a special grid of interlocking via structures is placed in between the underlying copper pad metal and the top tantalum nitride pad barrier layer providing improved adhesion to the aluminum pad metal stack structure. This unique contact bond pad structure provides for thermal stress relief, improved wire bond adhesion to the aluminum pad, and prevents peeling during wire bond adhesion tests.

Claims

1. A bond pad structure, comprising:

a semiconductor substrate;

a passivating layer forming multiple free-standing vertical islands to provide interlocking grid structures over said semiconductor substrate, wherein the vertical islands are separated by openings in said passivating layer;

a continuous barrier layer formed of tantalum nitride over said vertical islands of said passivating layer and in said openings; and

a conducting pad formed within said openings and over said interlocking grid structures and over said barrier layer, whereby an upper surface of said conductive pad provides improved adhesion for subsequently formed bonds.

2. The bond pad structure of claim 1, wherein said conductive pad is formed of copper.

3. The bond pad structure of claim 1, wherein said passivating layer is selected from the group consisting of silicon oxide, silicon nitride and polyimide.

5. The bond pad structure of claim 1, wherein said conductive bond pad is formed of aluminum.

4. A bond pad structure, comprising:

a semiconductor substrate;

comprising interlocking grid structures, formed over said semiconductor substrate;

a passivating layer, forming interlocking grid structures, said passivating layer having multiple openings to said interlocking grid structures to form multiple free-standing vertical islands;

a barrier layer formed of tantalum nitride over said passivating layer and in said openings, wherein said barrier layer is contiguous over said vertical islands;

a conducting pad formed over said interlocking grid structures and over said barrier layer, whereby an upper surface of said conductive pad provides improved adhesion for subsequently formed bonds,

wherein said bond pad forms an interlocking grid array in the bond pad via contact region, which is approximately 100 by 100 microns square and the size of the island structures are from about 10 to 25 microns in width, approximately 4 microns in height, and from about 4 to 10 in number, of interlocking grid structures, increasing surface area for improved adhesion.

6. A bond pad structure for a semiconductor device, the structure comprising:

an insulator layer adjacent to a semiconductor substrate;

a metal wiring layer adjacent to the insulator layer;

a passivation layer adjacent to the metal wiring layer, wherein at least a portion of the passivation layer is configured to provide a plurality of vertical island structures separated by spaces that expose a portion of the underlying metal wiring layer;

a contiguous metal barrier layer formed of tantalum nitride covering the islands of the passivation layer and the exposed portions of the metal wiring layer, wherein the metal barrier layer conforms to a shape provided by the island structures and does not completely fill the spaces between the island structures; and

a metal pad layer covering the metal barrier layer, wherein the metal pad layer fills the spaces between the island structures not filled by the metal barrier layer and rises above the island structures.

7. The bond pad structure of claim 6 wherein the metal barrier layer is substantially the same thickness throughout the bond pad structure.

8. The bond pad structure of claim 6 wherein the passivation layer is selected from the group consisting of silicon oxide, silicon nitride and polyimide.

9. The bond pad structure of claim 6 wherein the metal pad layer is formed of aluminum.