Refractory metal capped low resistivity metal conductor lines and vias

• US 5,300,813 A
• Filed: 02/26/1992
• Issued: 04/05/1994
• Est. Priority Date: 02/26/1992
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Hsu, Louis L., Joshi, Rajiv V., Dalal, Hormazdyar M., Cuomo, Jerome J.
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): BROWN, PETER T
• Application Number:
  US07/841,967
• Time in Patent Office: 769 Days
• Field of Search: 437/192, 437/194, 437/196-198, 257/751, 257/752, 257/767, 257/758, 257/759, 257/760, 257/754, 257/757, 257/763, 257/764, 257/766
• US Class Current: 257/752
• CPC Class Codes: H01L 21/76838 characterised by the formation and the after-treatment of the conductors etching for patterning the conductors H01L21/3213
• CPC Class Codes: H01L 21/7684 Smoothing; Planarisation
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76847 the layer being positioned within the main fill metal
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/76852 the layer also covering the sidewalls of the conductive structure
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 23/49866 characterised by the materials materials of the substrates H01L23/14, of the lead-frames H01L23/49579
• CPC Class Codes: H01L 23/53223 Additional layers associated with aluminium layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53228 the principal metal being copper
• CPC Class Codes: H01L 23/53233 Copper alloys
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: Y10S 148/015 Capping layer
• CPC Class Codes: Y10S 257/915 with titanium nitride portion or region
• CPC Class Codes: Y10S 438/959 Mechanical polishing of wafer

Abstract

A contact structure for a semiconductor device having a first refractory metal layer formed only at the bottom of a contact hole. The first refractory metal is selected from a group comprising titanium (Ti), titanium alloys or compounds such as Ti/TiN, tungsten (W), titanium/tungsten (Ti/W) alloys, or chromium (Cr) or tantalum (Ta) and their alloys or some other suitable material. A low resistivity layer comprising a single, binary or ternary metalization is deposited over the first refractory metal layer in the contact hole by a method such as PVD using evaporation or collimated sputtering. The low resistivity layer has side walls which taper inwardly toward one another with increasing height of the layer and the low resistivity layer does not contact the side walls of the contact hole. The low resistivity layer may be Al_x Cu_y (x+y=1; x≧0, y≧0), ternary alloys such as Al-Pd-Cu or multicomponent alloys such as Al-Pd-Nb-Au. A second refractory metal layer is deposited over the low resistivity layer. The second refractory metal layer may be tungsten, cobalt, nickel, molybdenum or alloys/compounds such as Ti/TiN. The first and second refractory metal layers completely encapsulate the low resistivity layer. The first and second refractory metal layers can comprise an alloy containing silicon with a higher incorporated silicon content near the top of the contact hold present as a distinct or graded composition than at a location closer to the bottom of the contact hole.

Claims

1. A device, comprising:

a substrate;

at least one dielectric layer positioned on said substrate; and

metalization positioned in an opening in said at least one dielectric layer and extending from a surface which is substantially co-planar with a surface of said at least one dielectric layer towards said substrate,

said metalization comprised of a low resistivity metal or alloy and being encapsulated by at least one refractory metal or alloy,

said low resistivity metal or alloy having side walls which taper inwardly towards one another towards said surface of said metalization which is planar with said surface of said at least one dielectric layer,

wherein said at least one refractory metal or alloy comprises an alloy containing silicon and has a higher incorporated silicon content at a location near said surface of said metalization present as one of a distinct and graded composition than at a location closer to said substrate.

2. A device as recited in claim 1, wherein said at least one refractory metal or alloy is selected from the group consisting of titanium, tungsten, tantalum, chromium and alloys, conducting oxides, nitrides and silicides thereof.

3. A device as recited in claim 1 wherein said low resistivity metal or alloy is a binary or ternary alloy of aluminum or copper.

4. A device as recited in claim 1, wherein said low resistivity metal is an alloy of aluminum and copper having the formula Al_x Cu_y, where the sum of x and y is equal to one and both x and y are greater than or equal to zero.

5. A device as recited in claim 1, wherein said at least one dielectric layer includes at least one inorganic layer.

6. A device as recited in claim 1, wherein said at least one dielectric layer includes at least one organic layer.

7. A device as recited in claim 1, wherein said at least one dielectric layer includes both inorganic and organic layers.

8. A device as recited in claim 1 wherein said substrate is a semiconductor.

9. A device as recited in claim 1, wherein said metalization extends completely through said at least one dielectric layer and contacts said substrate.