Method of forming an aluminum protection guard structure for a copper metal structure

• US 6,444,544 B1
• Filed: 08/01/2000
• Issued: 09/03/2002
• Est. Priority Date: 08/01/2000
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Hu, Chu-Wei, Lin, Chung-Te, Lin, Hsien-Chin, Pan, Kuo-Hua
• Primary Examiner(s): Everhart, Caridad
• Assistant Examiner(s): Lee, Calvin
• Application Number:
  US09/629,940
• Time in Patent Office: 763 Days
• Field of Search: 438/128, 438/132, 438/597, 438/601, 438/687, 438/688, 438/710, 438/720, 438/712, 438/73, 438/80, 438/89, 438/467, 438/470, 438/333, 327/525, 365/96, 365/200
• US Class Current: 438/467
• CPC Class Codes: H01L 23/5258 the change of state resulting from the use of an external beam, e.g. laser beam or ion beam
• CPC Class Codes: H01L 23/53228 the principal metal being copper
• CPC Class Codes: H01L 23/585 comprising conductive layers or plates or strips or rods or rings H01L23/60, H01L23/62, H01L23/64, H01L23/66 take precedence
• 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

Abstract

A method of forming aluminum guard structures in copper interconnect structures, used to protect the copper interconnect structures from a laser write procedure, performed to an adjacent copper fuse element, has been developed. The method features forming guard structure openings in an upper level of the copper interconnect structures, in a region adjacent to a copper fuse element. Deposition and patterning of an aluminum layer result in the formation of aluminum guard structures, located in the guard structure openings. The aluminum guard structures protect the copper interconnect structures from the oxidizing and corrosive effects of oxygen, fluorine and water ions, which are generated during a laser write procedure, performed to the adjacent copper fuse element.

Claims

1. A method of incorporating a metal guard structure in a multi-level metal interconnect structure, on a semiconductor substrate, with said metal guard structure formed adjacent to a metal fuse element, comprising the steps of:

forming a first multi-level metal interconnect structure in a first insulator layer, contacting a first group of array devices, located in said semiconductor substrate, and simultaneously forming a second multi-level metal interconnect structure in said first insulator layer, contacting a second group of array devices, located in said semiconductor substrate,

forming said metal fuse element in said first insulator layer, connecting said first multi-level metal interconnect structure, to said second multi-level metal interconnect structure;

depositing a second insulator layer;

forming a first opening in said second insulator layer, and in a top portion of said first insulator layer, exposing a bottom portion of said first insulator layer in a region in which said bottom portion of said first insulator layer is located overlying a top surface of said metal fuse element;

forming a second opening in said second insulator layer, in said top portion of said first insulator layer, and in said first multi-level metal interconnect structure, and simultaneously forming a third opening in said second insulator layer, in said top portion of said first insulator layer, and in said second multi-level metal interconnect structure; and

forming a first metal guard structure in said second opening, and simultaneously forming a second metal guard structure in said third opening.

2. The method of claim 1, wherein said first insulator layer is comprised of silicon oxide, or of borophosphosilicate glass.

3. The method of claim 1, wherein said first multi-level metal interconnect structure, and said second multi-level metal interconnect structure, are comprised of copper interconnect shapes, and copper via plug shapes, formed via deposition of a copper layer, which is obtained via either chemical vapor deposition, using plasma vapor deposition, or electroplating procedures, then followed by a patterning procedure, featuring photolithography and reactive ion etching, using Cl₂ or SF₆ as an etchant.

4. The method of claim 1, wherein the copper interconnect shapes, and copper via plug shapes, of said first multi-level metal interconnect structure, and of said second multi-level metal interconnect structure, are formed via a damascene procedure featuring openings made in a first insulator layer, deposition of a copper layer, and removal of unwanted regions of copper via a chemical mechanical polishing procedure.

5. The method of claim 1, wherein said metal fuse element is a damascene type, copper fuse element, obtained via opening a hole in said first insulator layer, at a depth between about 0 to 30,000 Angstroms, then depositing a copper layer to a thickness between about 2500 to 10,000 Angstroms, using either chemical vapor deposition, plasma vapor deposition, or electroplating procedures, followed by a chemical mechanical polishing procedure.

6. The method of claim 1, wherein said second insulator layer is comprised of silicon oxide, or borophosphosilicate glass.

7. The method of claim 1, wherein said first opening is a laser write opening, formed in said second insulator layer, and in a top portion of said first insulator layer, via photolithographic and reactive ion etching procedures, using CHF₃ as an etchant for the insulator layers.

8. The method of claim 1, wherein said second opening, and said third opening, are metal guard structure openings, formed in said second insulator layer, in a top portion of said first insulator layer, and in the multi-level metal level interconnect structures, via photolithographic and reactive ion etching procedures, using CHF₃ as an etchant for the insulator layers, while using either Cl₂ or SF₆ as an etchant for the multi-level metal interconnect structures.

9. The method of claim 1, wherein said first metal guard structure, and said second metal guard structure, are comprised of aluminum, obtained via plasma vapor deposition, at a thickness between about 5000 to 20,000 Angstroms, and defined via photolithographic and reactive ion etching procedures, using either Cl₂ or SF₆ as an etchant.

10. A method of forming aluminum metal guard structures in a multi-level copper interconnect structures, on a semiconductor substrate, with said aluminum guard structures formed adjacent to a copper fuse element, comprising the steps of:

forming a first multi-level copper interconnect structure in a first insulator layer, contacting a first group of array devices located in said semiconductor substrate, and simultaneously forming a second multi-level copper interconnect structure in said first insulator layer, contacting a second group of array devices located in said semiconductor substrate, wherein said first multi-level copper interconnect structure, and said second multi-level copper interconnect structure are comprised with copper interconnect shapes, and copper via plug shapes;

forming said copper fuse element in said first insulator layer, connecting said first multi-level copper interconnect structure to said second multi-level copper interconnect structure;

depositing a second insulator layer;

forming a laser write opening in said second insulator layer, and in a top portion of said first insulator layer, exposing a bottom portion of said first insulator layer in a region in which said bottom portion of said first insulator layer is located overlying a top surface of said copper fuse element;

forming a first opening in said second insulator layer, in said top portion of said first insulator layer, and in said first multi-level copper interconnect structure, and simultaneously forming a second opening in said second insulator layer, in said top portion of said first insulator layer, and in said second multi-level copper interconnect structure;

depositing an aluminum layer; and

patterning of said aluminum layer to form a first aluminum guard structure in said first opening, and simultaneously forming a second aluminum guard structure in said second opening.

11. The method of claim 10, wherein said first insulator layer is comprised of silicon oxide, or of borophosphosilicate glass.

12. The method of claim 10, wherein said copper interconnect shapes, and copper via plug shapes, of said first multi-level copper interconnect structure, and of said second multi-level copper interconnect structure, are formed via deposition of a copper layer, obtained via either chemical vapor deposition, using plasma vapor deposition, or of electroplating procedures, followed by a patterning procedure, featuring photolithography and reactive ion etching, using Cl₂ or SF₆ as an etchant.

13. The method of claim 10, wherein said copper interconnect shapes, and copper via plug shapes, of said first multi-level copper interconnect structure, and of said second multi-level copper interconnect structure, are formed via a damascene procedure featuring openings in first insulator layer, deposition of a copper layer, and removal of unwanted regions of copper via a chemical mechanical polishing procedure.

14. The method of claim 10, wherein said copper fuse element is a damascene type, copper fuse element, obtained via opening a hole in said first insulator layer, at a depth between about 0 to 30,000 Angstroms, then depositing a copper layer to a thickness between about 2500 to 10,000 Angstroms, using either chemical vapor deposition, plasma vapor deposition, or electroplating procedures, followed by a chemical mechanical polishing procedure.

15. The method of claim 10, wherein said second insulator layer is comprised of silicon oxide, or of borophosphosilicate glass.

16. The method of claim 10, wherein said laser write opening is formed in said second insulator layer, and in a top portion of said first insulator layer, via photolithographic and reactive ion etching procedures, using CHF₃ as an etchant for the insulator layers.

17. The method of claim 10, wherein said first opening, and said second opening, are metal guard structure openings, formed in said second insulator layer, in a top portion of said first insulator layer, and in the multi-level metal level interconnect structures, via photolithographic and reactive ion etching procedures, using CHF₃ as an etchant for the insulator layers, while using either Cl₂ or SF₆ as an etchant for the multi-level copper interconnect structures.

18. The method of claim 10, wherein said aluminum layer is obtained via plasma vapor deposition procedures, to a thickness between about 5000 to 20,000 Angstroms.

19. The method of claim 10, wherein said first aluminum guard structure, and said second aluminum guard structure, are defined via photolithographic and reactive ion etching procedures, using either Cl₂ or SF₆ as an etchant.

20. Metal guard structures, on a semiconductor substrate, located in multi-level copper interconnect structures, and located adjacent to a copper fuse element, comprising:

multi-level copper interconnect structures, in a composite insulator layer, with each multi-level copper interconnect structure connected to a group of underlying device elements, in said semiconductor substrate;

said copper fuse element in said composite insulator layer, located between said multi-level copper interconnect structures;

a laser write opening in a top portion of said composite insulator layer, exposing a lower portion of said composite insulator layer, with said lower portion of said composite insulator layer, exposed in said laser write opening, located on a top surface of said copper filse element;

metal guard openings in said top portion of said composite insulator layer, and in said multi-level copper interconnect structures, with said metal guard openings located adjacent to said copper fuse structure;

said metal guard structures in said metal guard openings; and

a protection ring in said composite insulator layer, surrounding said copper fuse structure, located between said copper fuse structure and said metal guard structures.

21. The metal guard structures of claim 20, wherein the thickness of said copper fuse element is between about 0 to 30,000 Angstroms.

22. The metal guard structures of claim 20, wherein said metal guard structures are comprised of aluminum, at a thickness between about 2500 to 20,000 Angstroms.

23. The metal guard structures of claim 20, wherein said protection ring is comprised of copper.