Compositions for improving interconnect metallization performance in integrated circuits

• US 6,459,153 B1
• Filed: 05/12/1999
• Issued: 10/01/2002
• Est. Priority Date: 05/12/1999
• Status: Expired due to Fees

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Sengupta, Samit S.
• Primary Examiner(s): Loke, Steven
• Assistant Examiner(s): VU, HUNG K
• Application Number:
  US09/310,875
• Publication Number:
  US 20020030275A1
• Time in Patent Office: 1,238 Days
• Field of Search: 257/758, 257/762, 257/767, 257/771, 257/772, 257/766, 257/765, 438/622, 438/687
• 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;

a plurality of interconnect metallization lines defined over the substrate, each of the interconnect metallization lines having an electromigration-impeding composition including a solid solution of aluminum and zinc grains of various sizes, the grains bounded by grain boundaries, the composition consisting essentially of,

a percentage by weight of aluminum;

a percentage by weight of copper; and

a percentage by weight of zinc; and

a precipitate of aluminum and copper defined in grain boundaries.

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

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

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

5. The semiconductor device as recited in claim 1, 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.

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

at least one metallization layer, the metallization layer having grains of various sizes 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.

7. The semiconductor device as recited in claim 6, 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.

8. The semiconductor device as recited in claim 7, 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.

9. The semiconductor device as recited in claim 6, 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.

10. The semiconductor device as recited in claim 6, 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.

11. An interconnect metallization line composition having electromigration-impeding properties, the metallization line composition comprising:

a solid solution of aluminum and zinc, consisting essentially of;

a percentage by weight of aluminum;

a percentage by weight of copper; and

a percentage by weight of zinc;

the solid solution being in the form of various size grains, and the grains being bounded by grain boundaries; and

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

12. The interconnect metallization line composition as recited in claim 11, 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 both defines the solid solution with aluminum and impedes the electromigration of the aluminum from the grains.

13. The interconnect metallization line composition as recited in claim 12, wherein the percentage by weight of copper is about 0.5.

14. The interconnect metallization line composition as recited in claim 11, wherein the percentage by weight of zinc is less than about 4.

15. The interconnect metallization line composition as recited in claim 14, wherein the percentage by weight of zinc ranges between about 1 and about 2.