COMPOSITIONS FOR IMPROVING INTERCONNECT METALLIZATION PERFORMANCE IN INTEGRATED CIRCUITS

• US 20020030275A1
• Filed: 05/12/1999
• Published: 03/14/2002
• Est. Priority Date: 05/12/1999
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: SENGUPTA, SAMIT S.
• Granted Patent: US 6,459,153 B1
• Time in Patent Office: Days
• US Class Current: 257/758
• 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 23/53219 Aluminium alloys
• 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 2924/3011 Impedance

Abstract

A semiconductor device includes a substrate and a plurality of interconnect metallization lines defined over the substrate, each interconnect metallization line being provided with an electromigration-impeding composition including a percentage by weight of aluminum, a percentage by weight of copper, and a percentage by weight of zinc. The percentage by weight of zinc may be less than about 4 in solid solution in Al at 100 degrees C, which is a substantial increase in the Zn content over the about 0.5 weight percent of the Cu content in previously-used Al—Cu alloys. The percentage by weight of Zn may preferably range between about 1 and 2. The electromigration-impeding composition of the lines may include a structure of a solid solution of Al and Zn in the form of grains. The grains are bounded by grain boundaries. The structure further includes a precipitate of Al and Cu defined in the grain boundaries. Electromigration of the Al from the grain boundaries occurs and tends to cause the Al to electromigrate from the grains. The percentage by weight of Zn is selected to both define the solid solution with Al and to impede the electromigration of the Al from the grains. A method of making an interconnect metallization layer on a substrate includes depositing a metallization composition on the substrate, wherein the composition is the above-described composition.

Claims

1. A semiconductor device, comprising:

a substrate; and

a plurality of interconnect metallization lines defined over the substrate, each of the interconnect metallization lines having an electromigration-impeding composition, the composition including,

a percentage by weight of aluminum;

a percentage by weight of copper; and

a percentage by weight of zinc.

2. A semiconductor device as recited in claim 1, wherein the percentage by weight of zinc is less than about 4.

3. A semiconductor device as recited in claim 1, wherein the percentage by weight of zinc ranges between about 1 and 2.

4. A semiconductor device as recited in claim 2, wherein the percentage by weight of copper is about 0.5.

5. A semiconductor device as recited in claim 1, wherein a structure of the electromigration-impeding composition includes,

a solid solution of aluminum and zinc.

6. A semiconductor device as recited in claim 5, wherein the solid solution is in the form of grains, and the grains are bounded by grain boundaries, wherein the structure further includes,

a precipitate of aluminum and copper defined in the grain boundaries.

7. A semiconductor device as recited in claim 6, wherein electromigration of the aluminum from the grain boundaries occurs and tends to cause the aluminum to electromigrate from the grains, wherein the percentage by weight of zinc is selected to both define the solid solution with aluminum and to impede the electromigration of the aluminum from the grains.

8. A method of making an interconnect metallization layer over a substrate, comprising:

depositing a metallization composition over the substrate, the composition including an aluminum component, a copper component, and a zinc component.

9. A method of making an interconnect metallization layer over a substrate as recited in claim 8, wherein the percentage by weight of the zinc component is less than about 4.

10. A method of making an interconnect metallization layer over a substrate as recited in claim 8, wherein the percentage by weight of the zinc component zinc ranges between about 1 and 2 percent by weight.

11. A method of making an interconnect metallization layer over a substrate as recited in claim 10, wherein the percentage by weight of the copper component is about 0.5 percent.

12. A method of making an interconnect metallization layer over a substrate as recited in claim 8, wherein a structure of the interconnect metallization layer includes, a solid solution of aluminum and zinc.

13. A method of making an interconnect metallization layer over a substrate as recited in claim 12, wherein the solid solution is in the form of grains, and the grains are bounded by grain boundaries, wherein the structure further includes,

a precipitate of aluminum and copper defined in the grain boundaries.

14. A method of making an interconnect metallization layer over a substrate as recited in claim 13, wherein electromigration tends to deplete the aluminum from the grain boundaries and cause migration of the aluminum from the grains, the percentage by weight of the zinc component being less than about 4 to delay the migration of the aluminum from the grains.

15. A method of making an interconnect metallization layer over a substrate as recited in claim 14, wherein the percentage by weight of the zinc component ranges between about 1 and 2 percent by weight.

17. A semiconductor device as recited in claim 16, wherein the layer includes a percentage by weight of the aluminum;

a percentage by weight of the copper; and

a percentage by weight of the zinc, and wherein the percentage by weight of zinc is less than about 4.

18. A semiconductor device as recited in claim 16, wherein the layer includes a percentage by weight of the aluminum;

a percentage by weight of the copper; and

a percentage by weight of the zinc, and wherein the percentage by weight of zinc ranges between about 1 and 2.

19. A semiconductor device as recited in claim 16, wherein the layer includes a percentage by weight of the aluminum;

a percentage by weight of the copper; and

a percentage by weight of the zinc, wherein the percentage by weight of zinc ranges between about 1 and 2, and wherein the percentage by weight of copper is about 0.5±

0.4.

20. A semiconductor device as recited in claim 17, further comprising:

the percentage by weight of the zinc being selected to both define the solid solution with aluminum and to impede the electromigration of the aluminum from the grains without substantially increasing the resistivity of the metallization layer.

16. A semiconductor device having improved interconnect metallization performance, comprising:

an interconnect metallization layer having grains bounded by grain boundaries, the grain boundaries having substantial amounts a precipitate of aluminum and copper defined in the grain;

at least one metallization layer, the metallization layer having grains bounded by grain boundaries, the grains including a solid solution of aluminum and zinc, the grain boundaries including a precipitate of aluminum and copper such that electromigration tends to deplete the aluminum from the grain boundaries and cause migration of the aluminum from the grains, the zinc being effective to improve interconnect metallization performance by impeding the migration of the aluminum from the grains.