Using polydentate ligands for sealing pores in low-k dielectrics

• US 7,163,900 B2
• Filed: 11/01/2004
• Issued: 01/16/2007
• Est. Priority Date: 11/01/2004
• Status: Expired due to Fees

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Weber, Frank
• Primary Examiner(s): Lee; Calvin
• Application Number:
  US10/978,540
• Publication Number:
  US 20060094256A1
• Time in Patent Office: 806 Days
• Field of Search: 430/106.2, 430/108, 438778-780, 438/788, 438/790, 438/793, 438/794
• US Class Current: 438/780
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/02304 formation of intermediate layers, e.g. buffer layers, layers to improve adhesion, lattice match or diffusion barriers
• CPC Class Codes: H01L 21/02318 post-treatment
• CPC Class Codes: H01L 21/31058 of organic layers
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass

Abstract

In preferred embodiments, a polydentate pore-sealing ligand is used to seal or repair pores damaged by plasma processing. The polydentate ligand includes bidentate ligands corresponding to the general formula X—CH₂—(CH₂)_n—CH₂—X or X—Si(CH₃)₂—(CH₂)_n—Si(CH₃)₂—X. The polydentate ligand also includes tridendate ligands corresponding to the general formula X—CH₂—(CH₂)_m(CXH)(CH₂)_o—CH₂—X or X—Si(CH₃)₂—(CH₂)_m(CXH)(CH₂)_o—Si(CH₃)₂—X. Alternative embodiments may include single or multiply branched polydentate ligands. Other embodiments include ligands that are cross-linked after attachment to the dielectric. Still other embodiments include a derivatization reaction wherein silanol groups formed by plasma damage are removed and favorable dielectric properties are restored.

Claims

1. A method for forming a carbon-containing, porous low-k dielectric layer on a semiconductor substrate, the method comprising:

providing a carbon containing, porous, low-k dielectric layer on said semiconductor substrate; and

treating the pores of said low-k, porous dielectric layer with a polydentate pore-sealing ligand.

2. The method of claim 1, wherein the polydentate pore-sealing ligand is a bidentate ligand.

3. The method of claim 2, wherein the bidentate ligand corresponds to the general formula X—

CH₂—

(CH₂)_n—

CH₂—

X;

wherein n=0–

2; and

wherein X is NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

4. The method of claim 2, wherein the bidentate ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_n—

Si(CH₃)₂—

X;

wherein n=0–

2; and

wherein X is H, NH₂, Cl, Br, I, —

OCH₃, —

SO₂F or triflate.

5. The method of claim 2, wherein the bidentate ligand is a branched ligand.

6. The method of claim 5, wherein the branched ligand corresponds to the general formula X—

CH₂—

(CH₂)_m(CR₁R₂)(CH₂)_o—

CH₂—

X;

wherein 2+m+o+1=n/2;

wherein R₁ and R₂ are independently H, Alkyl, or Aryl; and

wherein X is NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

7. The method of claim 1, wherein the polydentate pore-sealing ligand is a tridentate ligand.

8. The method of claim 7, wherein the tridentate ligand corresponds to the general formula X—

CH₂—

(CH₂)_m(CXH)(CH₂)_o—

CH₂—

X;

wherein m≈

o≈

n; and

wherein X is NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

9. The method of claim 7, wherein the tridentate ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_m(CXH)(CH₂)_o—

Si(CH₃)₂—

X;

wherein m≈

o≈

n; and

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

10. The method of claim 7, wherein the tridentate ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_m(SiXCH₃)(CH₂)_o—

Si(CH₃)₂—

X;

wherein m≈

o≈

n; and

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

11. The method of claim 1, wherein the polydentate pore-sealing ligand corresponds to the general formula X—

CH₂—

(CH₂)_m(CH(CH₂)_p—

X)(CH₂)_o—

CH₂—

X;

wherein m≈

o≈

p≈

n/2;

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

12. The method of claim 1, wherein the polydentate pore-sealing ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_m(CH(CH₂)_p—

X)(CH₂)_o—

Si(CH₃)₂—

X;

wherein m≈

o≈

p≈

n/2;

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

13. The method of claim 1, wherein the polydentate pore-sealing ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_m(CH(CH₂)_pSiX(CH₃)₂)(CH₂)_o—

Si(CH₃)₂—

X;

wherein m≈

o≈

p≈

n/2;

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

14. The method of claim 1, wherein the polydentate pore-sealing ligand corresponds to the general formula X—

CH₂—

(CH₂)_n—

Y;

wherein n=0–

3;

wherein X is H, NH₂, Cl, Br, OCH₃, —

SO₂F or triflate; and

wherein Y is O—

H, —

NH₂, amide, or imide.

15. The method of claim 1, wherein the polydentate pore-sealing ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_n—

Y;

wherein n=0–

3;

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate; and

wherein Y is O—

H, —

NH₂, amide, or imide.

16. The method of claim 1, wherein reacting the plurality of open pores with a polydentate pore-sealing ligand comprises the steps of reacting the polydentate pore-sealing ligand with the carbon-containing, porous, low-k insulator and then cross-linking the polydentate pore-sealing ligand.

17. The method of claim 1, wherein the carbon-containing, porous, low-k dielectric layer comprises a carbon-doped oxide.

18. The method of claim 1, wherein the carbon-containing, porous, low-k dielectric layer comprises porous silica.

19. The method of claim 1, wherein the carbon-containing, porous, low-k dielectric layer comprises OSG.

20. The method of claim 1 further comprising:

forming a silicon halide by reacting a silanol in the carbon-containing, porous, low-k dielectric layer with a halogenating agent; and

performing a derivatizing reaction with the silicon halide.

21. The method of claim 20, wherein the halogenating agent is selected from the group consisting essentially of thionyl chloride, sulfuryl chloride and carboxydichloride.

22. The method of claim 20, wherein the derivatizing reaction includes using an organometallic compound.

23. The method of claim 22, wherein the organometallic compound is selected from the group consisting essentially of a Grignard reagent, lithium dialkylcopper, trimethyl aluminum, and methyl lithium.

24. A method of fabricating a semiconductor device comprising:

forming an active device on a substrate;

depositing a carbon-containing, porous, low-k insulator over the active device;

exposing the insulator to a plasma;

sealing a plurality of open pores in the carbon-containing, porous, low-k insulator by reacting the plurality of open pores with a polydentate pore-sealing ligand.

25. The method of claim 24, wherein the polydentate pore-sealing ligand is a bidentate ligand.

26. The method of claim 25, wherein the bidentate ligand corresponds to the general formula X—

CH₂—

(CH₂)_n—

CH₂—

X;

wherein n=0–

2; and

wherein X is NH₂, Cl, Br, I, —

OCH₃, —

SO₂F or triflate.

27. The method of claim 25, wherein the bidentate ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_n—

Si(CH₃)₂—

X;

wherein n=0–

2; and

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

28. The method of claim 25, wherein the bidentate ligand is a branched ligand.

29. The method of claim 28, wherein the branched ligand corresponds to the general formula X—

CH₂—

(CH₂)_m(CR₁R₂)(CH₂)_o—

CH₂—

X;

wherein 2+m+o+1=n/2;

wherein R₁and R₂ are independently H, Alkyl, or Aryl; and

wherein X is NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

30. The method of claim 24, wherein the polydentate pore-sealing ligand is a tridentate ligand.

31. The method of claim 30, wherein the tridentate ligand corresponds to the general formula X—

CH₂—

(CH₂)_m(CXH)(CH₂)_o—

CH₂—

X;

wherein m, o≈

n; and

wherein X is NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

32. The method of claim 30, wherein the tridentate ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_m(CXH)(CH₂)_o—

Si(CH₃)₂—

X;

wherein m≈

o≈

n; and

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

33. The method of claim 30, wherein the tridentate ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_m(SiXCH₃)(CH₂)_o—

Si(CH₃)₂—

X;

wherein m≈

o ≈

n; and

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

34. The method of claim 24, wherein the polydentate pore-sealing ligand corresponds to the general formula X—

CH₂—

(CH₂)_m(CH(CH₂)_p—

X)(CH₂)_o—

CH₂—

X;

wherein m≈

o≈

p≈

n/2;

wherein X is NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

35. The method of claim 24, wherein the polydentate pore-sealing ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_m(CH(CH₂)_p—

X)(CH₂)_o—

Si(CH₃)₂—

X;

wherein m≈

o≈

p≈

n/2;

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

36. The method of claim 24, wherein the polydentate pore-sealing ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_m(CH(CH₂)_pSiX(CH₃)₂)(CH₂)_o—

Si(CH₃)₂—

X;

wherein m≈

o≈

p≈

n/2;

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate.

37. The method of claim 24, wherein the polydentate pore-sealing ligand corresponds to the general formula X—

CH₂—

(CH₂)_n—

Y;

wherein n=0–

3;

wherein X is NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate; and

wherein Y is —

O—

H, —

NH₂, amide, or imide.

38. The method of claim 24, wherein the polydentate pore-sealing ligand corresponds to the general formula X—

Si(CH₃)₂—

(CH₂)_n—

Y;

wherein n=0–

3;

wherein X is H, NH₂, Cl, Br, I, OCH₃, —

SO₂F or triflate; and

wherein Y is —

O—

H, —

NH₂, amide, or imide.

39. The method of claim 24, wherein reacting the plurality of open pores with a polydentate pore-sealing ligand comprises the steps of reacting the polydentate pore-sealing ligand with the carbon-containing, porous, low-k insulator and then cross-linking the polydentate pore-sealing ligand.

40. The method of claim 24, wherein the carbon-containing, porous, low-k insulator comprises a carbon-doped oxide.

41. The method of claim 24, wherein the carbon-containing, porous, low-k insulator comprises porous silica.

42. The method of claim 24, wherein the carbon-containing, porous, low-k insulator comprises OSG.

43. The method of claim 24 further comprising:

forming a silicon halide by reacting a silanol in the carbon-containing, porous, low-k insulator with a halogenating agent; and

performing a derivatizing reaction with the silicon halide.

44. The method of claim 43, wherein the halogenating agent is selected from the group consisting essentially of thionyl chloride, sulfuryl chloride and carboxydichloride.

45. The method of claim 43, wherein the derivatizing reaction includes using an organometallic compound.

46. The method of claim 43, wherein the organometallic compound is selected from the group consisting essentially of a Grignard reagent, lithium dialkylcopper, trimethyl aluminum, and methyl lithium.