Dielectric compositions and method for their manufacture

• US 6,107,357 A
• Filed: 11/16/1999
• Issued: 08/22/2000
• Est. Priority Date: 11/16/1999
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Volksen, Willi, Hedrick, James L., Miller, Robert D., Hawker, Craig Jon
• Primary Examiner(s): Foelak, Morton
• Application Number:
  US09/441,728
• Time in Patent Office: 280 Days
• Field of Search: 521/77, 521/134, 521/139, 521/138
• US Class Current: 521/77
• CPC Class Codes: C08J 2201/046 Elimination of a polymeric phase
• CPC Class Codes: C08J 2383/00 Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
• CPC Class Codes: C08J 9/26 by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out

Abstract

A novel dielectric composition is provided that is useful in the manufacture of electronic devices such as integrated circuit devices and integrated circuit packaging devices. The dielectric composition is prepared by crosslinking a thermally decomposable porogen to a host polymer via a coupling agent, followed by heating to a temperature suitable to decompose the porogen. The porous materials that result have dielectric constants less than about 3.0, with some materials having dielectric constants less than about 2.5. Integrated circuit devices, integrated circuit packaging devices, and methods of manufacture are provided as well.

Claims

1. A method for preparing a porous dielectric material, comprising:

(a) admixing, in a suitable solvent, (i) a thermally labile porogen having a reactive site that enables covalent attachment to another molecular moiety, (ii) a thermally stable, low dielectric constant host polymer having a glass transition temperature T_g, and (iii) a coupling agent effective to covalently bind to both the reactive site of the porogen and the host polymer;

(b) heating the admixture to a temperature T_C effective to couple the porogen to the host polymer via the coupling agent, whereby a polymeric matrix is formed in which the porogen is present as a discrete phase within a continuous phase formed by the host polymer; and

(c) heating the polymeric matrix to a temperature T_D effective to degrade the porogen without affecting the host polymer, thereby producing a dielectric material in the form of a porous structure, wherein T_D is greater than T_C but less than T_g.

2. The method of claim 1, wherein the host polymer is silicon-containing.

3. The method of claim 2, wherein the host polymer is comprised of a silisesquioxane, an alkoxysilane, an organic silicate, an orthosilicate, or a combination thereof.

4. The method of claim 3, wherein the host polymer is a silsesquioxane.

5. The method of claim 4, wherein the silsesquioxane is selected from the group consisting of hydrogen silsesquioxanes, alkyl silsesquioxanes, aryl silsesquioxanes, and derivatives and combinations thereof.

6. The method of claim 5, wherein the host polymer is selected from the group consisting of hydrogen silsesquioxanes, lower alkyl silsesquioxanes and phenyl silsesquioxanes.

7. The method of claim 3, wherein the host polymer is a copolymer of a polyimide and a silsesquioxane.

8. The method of claim 1, wherein the host polymer is a polyimide.

9. The method of claim 1, wherein the host polymer is a polybenzocyclobutene.

10. The method of claim 1, wherein the host polymer is a poly(arylene).

11. The method of claim 1, wherein the host polymer is a poly(arylene ether).

12. The method of claim 1, wherein the pre-process molecular weight of the host polymer is in the range of approximately 750 to 100,000.

13. The method of claim 1, wherein the porogen comprises a vinyl-based polymer.

14. The method of claim 1, wherein the porogen is a polymer comprised of monomer units selected from the group consisting of styrene, halogenated styrene, hydroxy-substituted styrene, lower alkyl-substituted styrene, acrylic acid, acrylamide, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, ethylene oxide, propylene oxide, and combinations thereof.

15. The method of claim 1, wherein the porogen is a crosslinked nanoparticle with reactive surface functionality.

16. The method of claim 14, wherein the porogen is poly(methyl methacrylate).

17. The method of claim 14, wherein the porogen is polystyrene.

18. The method of claim 14, wherein the porogen is poly(propylene oxide).

19. The method of claim 1, wherein the porogen is a polymer seleted from the group consisting of aliphatic polycarbonates, polyesters, polysulfones, polylactides, polylactones., and combinations thereof.

20. The method of claim 1, wherein the polymeric matrix is comprised of porogen domains averaging less than about 20 nm in diameter.

21. The method of claim 1, wherein the porogen represents in the range of about 5% to 35% of the polymeric matrix.

22. The method of claim 1, wherein the coupling agent has the formula R¹ --L--R² wherein R¹ is a functional group that enables covalent binding to the reactive site of the porogen, L is an hydrocarbylene linker containing at least two carbon atoms, and R² is a functional group that enables covalent binding to the host polymer.

23. The method of claim 22, wherein L is selected from the group consisting of alkylene, arylene and alkyl ether linkages, optionally substituted with one or more lower alkyl, halogen or aryl substituents.

24. The method of claim 23, wherein L is alkylene.

25. The method of claim 24, wherein L is C₂ -C₁₂ alkylene.

26. The method of claim 25, wherein L is C₂ -C₆ alkylene.

27. The method of claim 26, wherein L is n-propylene or n-butylene.

28. The method of claim 23, wherein L is arylene.

29. The method of claim 23, wherein L is an alkyl ether linkage.

30. The method of claim 22, wherein the reactive site of the porogen and the R¹ functional group are mutually reactive groups.

31. The method of claim 30, wherein the reactive site of the porogen is a hydroxyl or amino group, and R¹ is selected from the group consisting of an isocyanate, a ketene, cyano, an imino ether, a carbodiimide, an aldehyde and a ketone.

32. The method of claim 22, wherein the host polymer is a silsesquioxane and R² is --SiX₃ wherein at least one X is a leaving group.

33. The method of claim 32, wherein all three X moieties are leaving groups.

34. The method of claim 33, wherein each X is lower alkoxy or halo.

35. A method for preparing a porous dielectric material, comprising:

(a) admixing, in a suitable solvent, (i) a thermally labile porogen having at least one nucleophilic reactive site, (ii) a thermally stable, low dielectric constant host polymer comprised of a silsesquioxane, and (iii) a coupling agent R¹ --L--R² wherein R¹ is an isocyanate, a ketene, or cyano, L is --(CH₂)_n -- in which n is an integer in the range of 3 to 6, and R² is --SiX₃ wherein each X is lower alkoxy or halo;

(b) heating the admixture to a temperature T_C effective to couple the porogen to the host polymer via the coupling agent, such that R¹ binds to the reactive site of the porogen, R² binds to the host polymer, and a polymeric matrix is formed in which the porogen is dispersed within and coupled to host polymer, whereby a polymeric matrix is formed in which the porogen is present as a discrete phase within a continuous phase formed by the host polymer; and

(c) heating the crosslinked matrix to a temperature T_D effective to degrade the porogen without affecting the host polymer, thereby producing a low dielectric constant porous structure.

36. The method of claim 35, wherein T_C is in the range of approximately 150°

C. to 250°

C., and T_D is at least about 300°

C.

37. A two-phase polymeric matrix, comprising:

a continuous phase comprised of a thermally stable, low dielectric constant host polymer having a glass transition temperature T_g ; and

a discrete phase comprised of a thermally labile porogen,

wherein the porogen is covalently bound to the host polymer through a coupling agent and degrades at a temperature T_D that is lower than T_g.

38. The polymeric matrix of claim 37, wherein the host polymer is silicon-containing.

39. The polymeric matrix of claim 38, wherein the host polymer is comprised of a silisesquioxane, an alkoxysilane, an organic silicate, an orthosilicate, or a combination thereof.

40. The polymer matrix of claim 39, wherein the host polymer is a silsesquioxane.

41. The polymeric matrix of claim 40, wherein the silsesquioxane is selected from the group consisting of hydrogen silsesquioxanes, alkyl silsesquioxanes, aryl silsesquioxanes, and derivatives and combinations thereof.

42. The polymeric matrix of claim 41, wherein the host polymer is selected from the group consisting of hydrogen silsesquioxanes, lower alkyl silsesquioxanes and phenyl silsesquioxanes.

43. The polymeric matrix of claim 39, wherein the host polymer is a copolymer of a polyimide and a silsesquioxane.

44. The polymeric matrix of claim 37, wherein the host polymer is a polyimide.

45. The polymeric matrix of claim 37, wherein the host polymer is a polybenzocyclobutene.

46. The polymeric matrix of claim 37, wherein the host polymer is a poly(arylene).

47. The polymeric matrix of claim 37, wherein the host polymer is a poly(arylene ether).

48. The polymeric matrix of claim 37, wherein the host polymer is an organic thermosetting polymer.

49. The polymeric matrix of claim 37, wherein the host polymer is a crosslinked polymer.

50. The method of claim 37, wherein the porogen comprises a vinyl-based polymer.

51. The method of claim 37, wherein the porogen is a polymer selected from the group consisting of aliphatic polycarbonates, polyesters, polysulfones, polylactides, polylactones, and combinations thereof.

52. The polymeric matrix of claim 37, wherein the porogen is a polymer comprised of monomer units selected from the group consisting of styrene, halogenated styrene, hydroxy-substituted styrene, lower alkyl-substituted styrene, acrylic acid, acrylamide, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, ethylene oxide, propylene oxide, and combinations thereof.

53. The polymeric matrix of claim 52, wherein the porogen is poly(methyl methacrylate).

54. The polymeric matrix of claim 52, wherein the porogen is polystyrene.

55. The polymeric matrix of claim 52, wherein the porogen is poly(propylene oxide).

56. The polymeric matrix of claim 37, wherein the polymeric matrix is comprised of porogen domains averaging less than about 20 nm in diameter.

57. The polymeric matrix of claim 37, comprising approximately 5% to 35% porogen.