Sub-quarter-micron copper interconnections with improved electromigration resistance and reduced defect sensitivity

• US 6,069,068 A
• Filed: 10/08/1997
• Issued: 05/30/2000
• Est. Priority Date: 05/30/1997
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Smith, Richard G., McLaughlin, Paul S., Wachnik, Richard A., Rathore, Hazara S., Nguyen, Du B., Dalal, Hormazdyar M., Swinton, Alexander J.
• Primary Examiner(s): Beck, Shrive
• Assistant Examiner(s): CALCAGNI, JENNIFER A
• Application Number:
  US08/947,277
• Time in Patent Office: 965 Days
• Field of Search: 427/99, 427/123, 427/124, 438/687, 438/652, 438/654, 438/622, 438/624, 438/628, 438/629, 438/637, 438/638, 438/644, 438/658, 438/660, 438/666
• US Class Current: 438/628
• CPC Class Codes: H01L 21/76846 Layer combinations
• 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 21/76858 by diffusing alloying elements
• CPC Class Codes: H01L 21/76867 characterized by methods of formation other than PVD, CVD or deposition from a liquids PVD H01L21/2855; CVD H01L21/28556; deposition from liquids H01L21/288
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material

Abstract

A method of providing sub-half-micron copper interconnections with improved electromigration and corrosion resistance. The method includes double damascene using electroplated copper, where the seed layer is deposited by chemical vapor deposition, or by physical vapor deposition in a layer less than about 800 angstroms.

Claims

1. A method for forming multilevel interconnections of copper lines isolated from one another by dielectric insulation for making contacts to electrical features in a substrate, the method comprising the steps of:

(a) preparing a substrate having a dielectric insulation layer to receive copper lines in a defined pattern;

(b) optionally depositing a metallic liner in said pattern;

(c) depositing in said pattern a layer of an element capable of forming an intermetallic compound with copper wherein said element is selected from the group consisting of lanthanum and tin;

(d) subsequently depositing in said pattern a physical vapor deposition layer of copper having a thickness of less than about 800 angstroms;

(e) depositing over the physical vapor deposition copper layer by a different process a layer of copper to substantially fill said pattern; and

(f) heating the substrate to react the intermetallic forming element with said layer of copper which substantially fills said pattern to form a layer of intermetallic compound.

2. The method of claim 1 wherein the physical vapor deposition is by copper sputtering.

3. The method of claim 1 wherein the physical vapor deposition is by copper evaporation.

4. The method of claim 1 wherein the physical vapor deposition copper layer has a thickness below about 600 angstroms.

5. A method for forming multilevel interconnections of copper lines isolated from one another by dielectric insulation for making contacts to electrical features in a substrate, the method comprising the steps of:

(a) preparing a substrate having a dielectric insulation layer to receive copper lines in a defined pattern;

(b) optionally depositing a metallic liner in said pattern;

(c) depositing in said pattern a layer of an element capable of forming an intermetallic compound with copper wherein said element is selected from the group consisting of lanthanum and tin;

(d) subsequently depositing in said pattern a seed layer of copper by chemical vapor deposition, wherein said seed layer has a thickness less than about 800 angstroms;

(e) depositing over the copper seed layer by a different process a layer of copper to substantially fill said pattern; and

(f) heating the substrate to react the intermetallic forming element with said layer of copper which substantially fills said pattern to form a layer of intermetallic compound.

6. The method of claim 5 wherein the copper seed layer has a thickness less than about 600 angstroms.

7. A method for forming multilevel interconnections of copper lines isolated from one another by dielectric insulation for making contacts to electrical features in a substrate, the method comprising the steps of:

(a) preparing a substrate having a dielectric insulation layer to receive copper lines in a defined pattern;

(b) optionally depositing a metallic liner in said pattern;

(c) depositing in said pattern a layer of an element capable of forming an intermetallic compound with copper, wherein said element is selected from the group consisting of lanthanum, and tin;

(d) subsequently depositing in said pattern a chemical vapor deposition layer of copper; and

(e) depositing over the chemical vapor deposition copper layer by a different process a layer of copper to substantially fill said pattern; and

(f) heating the substrate to react the intermetallic forming element with said layer of copper which substantially fills said pattern to form a layer of intermetallic compound.

8. The method of claim 7 wherein the chemical vapor deposition copper layer has a thickness of about 100 to 700 angstroms.

9. A method for forming multilevel interconnections of copper lines isolated from one another by dielectric insulation for making contacts to electrical features in a substrate, the method comprising the steps of:

(a) preparing a substrate having a dielectric insulation layer to receive copper lines in a defined pattern;

(b) optionally depositing a metallic liner in said pattern;

(c) depositing in said pattern a layer of an element capable of forming an intermetallic compound with copper, wherein said element is selected from the group consisting of lanthanum, and tin;

(d) subsequently depositing in said pattern a seed layer of copper by a process selected from the group consisting of chemical vapor deposition and physical vapor deposition, wherein said seed layer has a thickness less than about 800 angstroms;

(e) depositing over the copper seed layer by a different process a layer of copper to substantially fill said pattern; and

(f) heating the substrate to react the intermetallic forming element with said layer of copper which substantially fills said pattern to form a layer of intermetallic compound.

10. The method of claim 9 wherein the copper seed layer has a thickness less than about 600 angstroms.

11. The method of claim 9 wherein the copper seed layer is deposited by physical vapor deposition.

12. The method of claim 9 wherein the copper seed layer is deposited by chemical vapor deposition.