Producing SOI structure using high-purity ion shower

• US 20070281399A1
• Filed: 05/31/2006
• Published: 12/06/2007
• Est. Priority Date: 05/31/2006
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Gadkaree, Kishor Purushottam, Maschmeyer, Richard Orr, Cites, Jeffrey Scott
• Granted Patent: US 7,608,521 B2
• Time in Patent Office: Days
• US Class Current: 438/149
• CPC Class Codes: H01L 21/26506 in group IV semiconductors
• CPC Class Codes: H01L 21/76254 with separation/delamination along an ion implanted layer, e.g. Smart-cut, Unibond

Abstract

Disclosed are methods for making SOI and SOG structures using purified ion shower for implanting ions to the donor substrate. The purified ion shower provides expedient, efficient, low-cost and effective ion implantation while minimizing damage to the exfoliation film.

Claims

1. A process for forming a SOI structure comprising the following steps:

(I) providing a donor substrate comprising semiconductor material having a first donor external surface; and

(II) implanting a plurality of ions belonging to a first species through the first donor external surface into an ion implantation zone at a depth below the first donor external surface by using a first ion shower purified by electromagnetic separation such that the structure of at least a 50 nm thick part of the material sandwiched between the ion implantation zone and the first donor external surface (“

exfoliation film”

) is essentially not damaged.

2. A process according to claim 1, wherein in step (II), at least a 100 nm thick part, in certain embodiments at least a 150 nm thick part, in certain embodiments at least a 200 nm thick part, of the exfoliation film is essentially not damaged.

3. A process according to claim 1, wherein the exfoliation film comprises single crystalline silicon.

4. A process according to claim 1, wherein in step (II), the ion implantation zone has a thickness of not larger than about 1 μ

m, in certain embodiments not larger than about 500 nm, in certain other embodiments not larger than about 300 nm, in certain other embodiments not larger than about 200 nm.

5. A process according to claim 1, wherein in step (II), the depth of the ion implantation zone is less than about 1000 nm, in certain embodiments less than about 500 nm, in certain other embodiments less than about 300 nm, in certain other embodiments less than about 150 nm, in certain other embodiments less than about 100 nm.

6. A process according to claim 1, wherein the thickness of the non-damaged part of the exfoliation film is at least 50% of the total thickness of the exfoliation film, in certain embodiments at least 60% of the total thickness of the exfoliation film, in certain embodiments at least 80% of the total thickness of the exfoliation film, in certain embodiments at least 90%.

7. A process according to claim 1, wherein in step (II), the first ion shower consists essentially of the ions belonging to a first species.

8. A process according to claim 7, wherein the ions belonging to the first species is a single ion species selected from H₃⁺, H⁺, H₂⁺, D₂⁺, D₃⁺, HD+, H₂D⁺, HD₂⁺, He⁺, He²⁺, O⁺, O₂⁺, O²⁺ and O₃⁺.

9. A process according to claim 7, wherein the ions belonging to the first species are essentially free of phosphorous, boron, arsenic, carbon, oxygen, nitrogen, fluorine, chlorine and metals.

10. A process according to claim 1, further comprising the following step (III) separate from and independent of step (II):

(III) implanting a plurality of ions belonging to a second species through the first donor external surface into the ion implantation zone at the depth below the first donor external surface by using a second ion shower purified by electromagnetic separation such that the structure of at least a 50 nm thick part the exfoliation film is essentially not damaged, said ions belonging to the second species being different from the ions belonging to the first species.

11. A process according to claim 10, wherein in step (III), at least a 100 nm thick part, in certain embodiments at least a 150 nm thick part, in certain embodiments at least a 200 nm thick part, of the exfoliation film is essentially not damaged.

12. A process according to claim 10, wherein the ion implantation zone comprises a first ion implantation zone where the ions belonging to the first ion species are implanted and a second ion implantation zone where the ions belonging the second ion species are implanted, and the first ion implantation zone and the second ion implantation zone substantially overlap.

13. A process according to claim 12, wherein the distance between the density peak of the first species of ions in the first ion implantation zone and the density peak of the second species of ions in the second ion implantation zone is less than about 100 mm.

14. A process according to claim 1, further comprising the following step (IIIA) separate from and independent of step (II):

(IIIA) implanting a plurality of ions through the first donor external surface into the ion implantation zone at the depth below the first donor external surface by using a beam-line implanter.

15. A process according to claim 1, further comprising the following step (IIIB) separate from and independent of step (II):

(IIIB) implanting a plurality of ions through the first donor external surface into the ion implantation zone at the depth below the first donor external surface by using a conventional ion shower.

16. A process according to claim 10, wherein the ions belonging to the first species are H₃⁺, and the ions belonging to the second species are He⁺.

17. A process according to claim 16, wherein ratio of the energy of H₃⁺ to that of the He⁺ is about 2:

1.

18. A process according to claim 16, wherein the H₃⁺ has an energy of about 60 KeV, and the He⁺ has an energy of about 30 KeV.

19. A process according to claim 1, further comprising the following step (IV):

(IV) bonding the first donor external surface to a recipient substrate.

20. A process according to claim 1, further comprising the following step (V):

(V) separating the exfoliation film and at least part of the material in the ion implantation zone from the donor substrate at a location within the implantation zone.

21. A process according to claim 19, further comprising the following step (V):

(V) separating the exfoliation film and at least part of the material in the ion implantation zone from the donor substrate at a location within the implantation zone.

22. A process according to claim 19, wherein the recipient substrate is selected from the group consisting of:

a semiconductor wafer with or without an oxide surface layer;

a glass plate;

plate comprised of crystalline material and a glass-ceramic plate.

23. A process according to claim 19, wherein the recipient substrate is a silicon wafer with a SiO₂ surface layer, and the first donor external surface of is bonded to the SiO₂ surface layer in step (IV).

24. A process according to claim 19, wherein the recipient substrate is a SiO₂ glass plate.

25. A process according to claim 19, wherein:

(1) the recipient substrate comprises oxide glass or oxide glass-ceramic; and

(2) in step (IV), the bonding is effected by applying (a) forces to the donor and recipient substrates such that they are pressed into close contact;

(b) electrical field within the donor and recipient substrates such that the electrical potential in the donor substrate is higher than that in the recipient substrate; and

(c) a temperature gradient between the donor and recipient substrates.

26. A process according to claim 1, wherein in step (II), the electromagnetic separation of the first ion shower is effected by magnetic means.

27. A process for forming a SOI structure comprising the following steps:

(A1) providing a donor substrate and a recipient substrate, wherein;

(1) the donor substrate comprises a semiconductor material and a first donor external surface for bonding with the recipient substrate (first bonding surface) and a second donor external surface;

(2) the recipient substrate comprises an oxide glass or oxide glass-ceramic and two external surfaces;

(i) a first recipient external surface for bonding to the first substrate (the second bonding surface); and

(ii) a second recipient external surface;

(A2) implanting a plurality of ions belonging to a first species through the first donor external surface into an ion implantation zone of the donor substrate at a depth below the first donor external surface by using a first ion shower purified by electromagnetic separation such that the internal structure of at least a 50 nm thick part of the film of material sandwiched between the ion implantation zone and the first donor external surface (“

exfoliation film”

) is essentially not damaged;

(B) after steps (A1) and (A2), bringing the first and second bonding surfaces into contact;

(C) for a period of time sufficient for the donor and recipient substrates to bond to one another at the first and second bonding surfaces, simultaneously;

(1) applying forces to the donor substrate and/or the recipient substrate such that the first and second bonding surfaces are pressed into contact;

(2) subjecting the donor and recipient substrates to an electric field having a general direction of from the second recipient external surface to the second donor external surface; and

(3) heating the donor and recipient substrates, said heating being characterized in that the second donor and recipient external surfaces have average temperatures T₁ and T₂, respectively, said temperatures being selected such that upon cooling to a common temperature, the donor and recipient substrates undergo differential contraction to thereby weaken the donor substrate at the ion implantation zone; and

(D) cooling the bonded donor and recipient substrates and splitting the donor substrate at the ion implantation zone;

wherein the oxide glass or oxide glass-ceramic comprises positive ions which during step (C) move within the recipient substrate in a direction away from the second bonding surface and towards the second recipient external surface.

28. A process according to claim 27, wherein in step (A2), the structure of at least a 100 nm thick part, in certain embodiments at least a 150 nm thick part, in certain embodiments at least a 200 nm thick part, of the exfoliation film is not damaged.

29. A process according to claim 27, wherein the exfoliation film comprises single crystalline semiconductor material.

30. A process according to claim 27, wherein the exfoliation film comprises single crystalline silicon.

31. A process according to claim 27, wherein in step (II), the depth of the ion implantation zone is less than about 1000 nm, in certain embodiments less than about 500 nm, in certain other embodiments less than about 300 nm, in certain other embodiments less than about 150 nm, in certain other embodiments less than about 100 nm.

32. A process according to claim 27, wherein the thickness of the non-damaged part of the exfoliation film is at least 50% of the total thickness of the exfoliation film, in certain embodiments at least 60% of the total thickness of the exfoliation film, in certain embodiments at least 80% of the total thickness of the exfoliation film, in certain embodiments at least 90%.

33. A process according to claim 27, wherein in step (A2), the ion implantation zone has a thickness of not larger than about 1 μ

m, in certain embodiments not larger than about 500 nm, in certain other embodiments not larger than about 300 nm, in certain other embodiments not larger than about 200 nm.

34. A process according to claim 27, wherein in step (A2), the first ion shower consists essentially of the ions belonging to a first species.

35. A process according to claim 34, wherein the ions belonging to the first species is a single ion species selected from H₃⁺, H⁺, H₂⁺, D₂⁺, D₃⁺, HD⁺, H₂D⁺, HD₂⁺, He⁺, He²⁺, O⁺, O₂⁺, O₂⁺ and O₃⁺.

36. A process according to claim 34, wherein the ions belonging to the first species are essentially free of phosphorous, boron, arsenic, carbon, oxygen, nitrogen, fluorine, chlorine and metals.

37. A process according to claim 27, further comprising the following step (A3) separate and independent from step (A2):

(A3) implanting a plurality of ions belonging to a second species through the first donor external surface into the ion implantation zone at the depth below the first donor external surface by using a second ion shower purified by electromagnetic separation such that the structure of at least a 50 nm thick part of the exfoliation film is essentially not damaged, said ions belonging to the second species being different from the ions belonging to the first species.

38. A process according to claim 37, wherein in step (A3), at least a 100 nm thick part, in certain embodiments at least a 150 nm thick part, in certain embodiments at least a 200 nm thick part, of the exfoliation film is essentially not damaged.

39. A process according to claim 37, wherein the ion implantation zone comprises a first ion implantation zone where the ions belonging to the first ion species are implanted and a second ion implantation zone where the ions belonging the second ion species are implanted, and the first ion implantation zone and the second ion implantation zone substantially overlap.

40. A process according to claim 39, wherein the distance between the density peak of the first species of ions in the first ion implantation zone and the density peak of the second species of ions in the second ion implantation zone is less than about 100 nm.

41. A process according to claim 37, wherein the ions belonging to the first species are H₃⁺, and the ions belonging to the second species are He⁺.

42. A process according to claim 41, wherein the ratio of the energy of H₃⁺ to that of the He⁺ is about 2:

1.

43. A process according to claim 41, wherein the H₃⁺ has an energy of about 60 KeV, and the He⁺ has an energy of about 30 KeV.

44. A process according to claim 27, wherein in step (A2), the electromagnetic separation of the first ion shower is effected by magnetic means.

45. A process according to claim 27, wherein after step (A2) but before step (B), the first bonding surface of the donor substrate is treated to reduce the hydrogen concentration thereof.

46. A process according to claim 45, wherein the hydrogen-concentration-reducing treatment causes the first bonding surface to be hydrophilic.

47. A process according to claim 45, wherein the hydrogen-concentration-reducing treatment is selected from oxygen plasma treatment, ozone treatment, treatment with H₂O₂, treatment with H₂O₂ and ammonia, treatment with H₂O₂ and an acid, and combinations thereof.