Structures and methods to enhance copper metallization

• US 6,420,262 B1
• Filed: 01/18/2000
• Issued: 07/16/2002
• Est. Priority Date: 01/18/2000
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Farrar, Paul A.
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): BERRY, RENEE R
• Application Number:
  US09/483,869
• Time in Patent Office: 910 Days
• Field of Search: 438/652, 438/622, 438/637, 438/618, 438/633, 438/659, 438/672, 438/687
• US Class Current: 438/652
• CPC Class Codes: H01L 21/32051 Deposition of metallic or metal-silicide layers
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors
• CPC Class Codes: H01L 21/76823 transforming an insulating layer into a conductive layer
• CPC Class Codes: H01L 21/76825 by exposing the layer to particle radiation, e.g. ion implantation, irradiation with UV light or electrons etc. plasma treatment H01L21/76826
• CPC Class Codes: H01L 21/76828 thermal treatment
• CPC Class Codes: H01L 21/76831 in via holes or trenches, e.g. non-conductive sidewall liners
• CPC Class Codes: H01L 21/76841 Barrier, adhesion or liner layers
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76855 After-treatment introducing at least one additional element into the layer
• CPC Class Codes: H01L 21/76859 by ion implantation
• 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 21/76874 for electroless plating
• CPC Class Codes: H01L 21/76879 by selective deposition of conductive material in the vias, e.g. selective C.V.D. on semiconductor material, plating plating on semiconductors in general H01L21/288
• CPC Class Codes: H01L 21/7688 by deposition over sacrificial masking layer, e.g. lift-off lift-off per se H01L21/0272
• CPC Class Codes: H01L 23/53228 the principal metal being copper
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/5329 Insulating materials
• CPC Class Codes: H01L 23/53295 Stacked insulating 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

Abstract

Structures and methods are described that inhibit atomic migration which otherwise creates an undesired capacitive-resistive effect arising from a relationship between a metallization layer and an insulator layer of a semiconductor structure. A layer of an inhibiting compound may be used to inhibit a net flow of atoms so as to maintain conductivity of the metallization layer and maintain the low dielectric constant of a suitable chosen insulator material. Such a layer of inhibiting compound continues to act even with the reduction of ground rules in succeeding generations of semiconductor processing technology.

One embodiment includes an insulator having a first substance, wherein the first substance is selected from a group consisting of a polymer and an insulating oxide compound. The embodiment includes an inhibiting layer on the insulator, wherein the inhibiting layer includes a compound formed from a reaction that includes the first substance and a second substance. The second substance is selected from a group consisting of a transition metal, a representative metal, and a metalloid. The embodiment includes a highly conductive metallization layer on the inhibiting layer.

Claims

1. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having a first substance, wherein the first substance comprises a material having a plurality of single hydrocarbon molecule bonded together;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing a second substance on the insulator layer, and wherein forming the inhibiting layer includes reacting the first substance and the second substance to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization layer on the inhibiting layer.

2. The method of claim 1, wherein forming the insulator layer includes forming with a material that is selected from a group consisting of a polymer, a foamed polymer, a fluorinated polymer, and a fluorinated-foamed. polymer.

3. The method of claim 2, wherein forming the insulator layer includes forming with a material that is selected from a group consisting of a polyimide, a foamed polyimide, a fluorinated polyimide, and a fluorinated-foamed polyimide.

4. The method of claim 3, wherein forming the insulator layer includes forming with a material that is selected from a group consisting of DuPont PI-2801 material, a foamed DuPont PI-2801 material, a fluorinated DuPont PI-2801 material, and a fluorinated-foamed DuPont PI-2801 material.

5. The method of claim 1, wherein forming the insulator layer includes forming with a material that comprises at least two mers bonded together that have been treated so as to have a low dielectric constant.

47. The method of claim 1, wherein reacting the first substance and the second substance to form a compound so as to inhibit undesired atomic migration comprises annealing the first and second substances or establishing a temperature in the range of 325 to 375 degrees Celsius.

6. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having a first substance, wherein the first substance comprises a material selected from a group consisting of a polymer, a foamed polymer, a fluorinated polymer, and a fluorinated-foamed polymer;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing a second substance on the insulator layer, wherein the second substance is selected from a group consisting of a transition metal, a representative metal, and a metalloid, and wherein forming the inhibiting layer includes reacting the first substance and the second substance to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization layer on the inhibiting layer.

7. The method of claim 6, wherein the depositing process of forming the inhibiting layer includes depositing with a transition metal, wherein the transition metal is selected from a group consisting of chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium, and tantalum.

8. The method of claim 6, wherein the depositing process of forming the inhibiting layer includes depositing with a representative metal that includes an alkaline earth metal.

9. The method of claim 6, wherein the depositing process of forming the inhibiting layer includes depositing with a representative metal that is selected from a group consisting of aluminum and magnesium.

10. The method of claim 6, wherein the depositing process of forming the inhibiting layer includes depositing with a metalloid that comprises boron.

11. The method of claim 7, wherein the depositing process of forming the inhibiting layer includes depositing a layer of zirconium with a thickness of about 5 Angstroms to about 40 Angstroms.

12. The method of claim 8, wherein the depositing process of forming the inhibiting layer includes depositing a layer of alkaline earth metal with a thickness of about 5 Angstroms to about 40 Angstroms, and wherein the alkaline earth metal includes magnesium.

13. The method of claim 9, wherein the depositing process of forming the inhibiting layer includes depositing a layer of aluminum with a thickness of about 5 Angstroms to about 40 Angstroms.

48. The method of claim 6, wherein reacting the first substance and the second substance to form a compound so as to inhibit undesired atomic migration comprises annealing the first and second substances or establishing a temperature in the range of 325 to 375 degrees Celsius.

14. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having a first substance, wherein the first substance comprises a material selected from a group consisting of a polymer, a foamed polymer, a fluorinated polymer, and a fluorinated-foamed polymer;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing a second substance on the insulator layer, wherein depositing the second substance includes depositing the second substance using a technique selected from a group consisting of low-energy implantation and chemical vapor deposition, wherein the second substance is selected from a group consisting of a transition metal, a representative metal, and;

a metalloid, and wherein forming the inhibiting layer includes reacting the first substance and the second substance to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization on the inhibiting layer.

15. The method of claim 14, wherein the depositing process of forming the inhibiting layer includes implanting with an implantation energy of about 100 electron-volts to about 2000 electron-volts.

16. The method of claim 14, wherein the depositing process of forming the inhibiting layer includes depositing in a temperature of about 250 degrees Celsius to about 375 degrees Celsius.

49. The method of claim 14, wherein reacting the first substance and the second substance to form a compound so as to inhibit undesired atomic migration comprises annealing the first and second substances or establishing a temperature in the range of 325 to 375 degrees Celsius.

17. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having a first substance, wherein the first substance comprises a material selected from a group consisting of a polyimide or a foamed polyimide;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing zirconium on the insulator layer, wherein depositing the zirconium includes implanting zirconium using a low-energy implantation technique, and wherein forming the inhibiting layer includes reacting the first substance and zirconium to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization layer on the inhibiting layer.

18. The method of claim 17, wherein the depositing process of forming the inhibiting layer includes implanting a dose of zirconium at about 5×

10¹⁶ ions per square centimeters.

19. The method of claim 18, wherein the depositing process of forming the inhibiting layer includes implanting at about 400 electron-volts to about 600 electron-volts.

20. The method of claim 19, wherein the depositing process of forming the inhibiting layer includes implanting at an angle of about 5 degrees to about 10 degrees from normal with respect to the insulator layer.

21. The method of claim 17, wherein the reacting process of forming the inhibiting layer includes reacting to form the compound at about 325 degrees Celsius to about 375 degrees Celsius.

22. The method of claim 21, wherein the reacting process of forming the inhibiting layer includes reacting to form the compound at about 325 degrees Celsius to about 375 degrees Celsius for about 27 minutes to about 33 minutes.

23. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having an insulator oxide compound;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing aluminum on the insulator layer, wherein depositing aluminum includes implanting aluminum using a low-energy implantation technique, and wherein forming the inhibiting layer includes reacting the oxide compound and aluminum to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization layer on the inhibiting layer.

24. The method of claim 23, wherein the depositing process of forming the inhibiting layer includes implanting a dose of aluminum at about 5×

10¹⁶ ions per square centimeters.

25. The method of claim 24, wherein the depositing process of forming the inhibiting layer includes implanting at about 400 electron-volts.

26. The method of claim 25, wherein the depositing process of forming the inhibiting layer includes implanting at an angle of about 5 degrees to about 10 degrees from normal with respect to the insulator layer.

27. The method of claim 23, wherein the reacting process of forming the inhibiting layer includes reacting to form the compound at about 325 degrees Celsius to about 375 degrees Celsius.

28. The method of claim 27, wherein the reacting process of forming the inhibiting layer includes reacting to form the compound at about 325 degrees Celsius to about 375 degrees Celsius for about 27 minutes to about 33 minutes.

29. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having a first substance, wherein the insulator layer is formed with a first thickness;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing a second substance on the insulator layer, and wherein forming the inhibiting layer includes reacting the first substance and the second substance to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization layer on the inhibiting layer with a second thickness.

30. The method of claim 29, wherein the second thickness of the copper metallization layer is proportional to the first thickness of the insulator layer.

31. The method of claim 29, further comprising etching a pattern for the copper metallization layer after forming the insulator layer and before forming the inhibiting layer.

32. The method of claim 29, wherein the depositing process of forming the inhibiting layer includes implanting a dose of about 5×

10¹⁶ per square centimeters of the second substance, wherein implanting includes implanting at about 400 electron-volts to about 600 electron-volts, wherein implanting includes implanting at an angle of about 5 degrees to about 10 degrees from normal with respect to the insulator layer.

50. The method of claim 29, wherein reacting the first substance and the second substance to form a compound so as to inhibit undesired atomic migration comprises annealing the first and second substances or establishing a temperature in the range of 325 to 375 degrees Celsius.

33. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having a first substance, wherein the insulator layer is formed with a first thickness;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing a second substance on the insulator layer, and wherein forming the inhibiting layer includes reacting the first substance and second substance to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization layer on the inhibiting layer with a second thickness, wherein the second thickness of the copper metallization layer is proportional to the first thickness of the insulator layer.

34. The method of claim 33, further comprising etching a pattern for the copper metallization layer after forming the insulator layer and before forming the inhibiting layer.

36. The method of claim 33, wherein the reacting process of forming the inhibiting layer includes reacting to form the compound through a heat-treatment process for a time period.

35. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having a first substance, wherein the insulator layer is formed with a first thickness;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing a second substance on the insulator layer using low energy at a angle with respect to normal of the insulator layer, and wherein forming the inhibiting layer includes reacting the first substance and second substance to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization layer on the inhibiting layer with a second thickness, wherein the second thickness of the copper metallization layer is proportional to the first thickness of the insulator layer.

37. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having a first substance, wherein the first substance comprises a material selected from a group consisting of a polymer, a foamed polymer, a fluorinated polymer, a fluorinated-foamed polymer, and an oxide compound;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing a second substance on the insulator layer, wherein depositing the second substance includes depositing the second substance using a technique selected from a group consisting of low-energy implantation and chemical vapor deposition, wherein the second substance is selected from a group consisting of a transition metal, a representative metal, and a metalloid, and wherein forming the inhibiting layer includes reacting the first substance and second substance to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization layer on the inhibiting layer.

38. The method of claim 37, wherein forming a copper metallization layer includes forming a shape in the insulator layer to be occupied by a portion of a copper metallization layer using a damascene process.

39. The method of claim 38, wherein forming the shape includes forming a line structure and vias.

40. The method of claim 37, wherein forming the insulator layer includes forming with an oxide compound that comprises silicon dioxide.

41. The method of claim 37, wherein the depositing process of forming the inhibiting includes depositing the second substance throughout the surfaces of the insulator layer.

44. The method of claim 37, wherein forming the inhibiting layer includes forming the compound by reacting the second substance with the first substance to from an in situ barrier.

45. The method of claim 44, wherein reacting includes reacting the second substance with the first substance through an annealing process.

46. The method of claim 45, wherein reacting includes reacting prior to a completion of the semiconductor structure.

42. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having a first substance, wherein the first substance comprises a material selected from a group consisting of a polymer, a foamed polymer, a fluorinated polymer, a fluorinated-foamed polymer, and an oxide compound;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing a second substance on the insulator layer, wherein depositing the second substance includes depositing the second substance using a technique selected from a group consisting of low-energy implantation and chemical vapor deposition, depositing the second substance throughout the surfaces of the insulator layer and implanting the second substance at an angle of about 3 to about 15 degrees from normal, wherein the second substance is selected from a group consisting of a transition metal, a representative metal, and a metalloid, and wherein forming the inhibiting layer includes reacting the first substance and second substance to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization layer on the inhibiting layer.

43. A method for forming an enhanced metallization layer, the method comprising:

forming an insulator layer having a first substance, wherein the first substance comprises a material selected from a group consisting of a polymer, a foamed polymer, a fluorinated polymer, a fluorinated-foamed polymer, and an oxide compound;

forming an inhibiting layer on the insulator layer, wherein forming the inhibiting layer includes depositing a second substance on the insulator layer, wherein depositing the second substance includes depositing the second substance using a technique selected from a group consisting of low-energy implantation and chemical vapor deposition, depositing the second substance throughout the surfaces of the insulator layer and implanting the second substance at an angle of about 3 to about 15 degrees from normal, wherein implanting includes implanting the second substance at an angle that is dependent on the height to width ratio of the semiconductor structure, wherein the second substance is selected from a group consisting of a transition metal, a representative metal, and a metalloid, and wherein forming the inhibiting layer includes reacting the first substance and second substance to form a compound so as to inhibit undesired atomic migration; and

forming a copper metallization layer on the inhibiting layer.