Process of producing semiconductor article

• US 6,375,738 B1
• Filed: 03/24/2000
• Issued: 04/23/2002
• Est. Priority Date: 03/26/1999
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sato, Nobuhiko
• Primary Examiner(s): KUNEMUND, ROBERT M
• Application Number:
  US09/534,068
• Time in Patent Office: 760 Days
• Field of Search: 117/89, 117/104, 117/915, 117/95, 117/94
• US Class Current: 117/89
• CPC Class Codes: H01L 21/306 Chemical or electrical treatment, e.g. electrolytic etching to form insulating layers H01L21/31
• CPC Class Codes: H01L 21/76259 with separation/delamination along a porous layer
• CPC Class Codes: Y10S 117/915 Separating from substrate

Abstract

A process of producing a semiconductor article is disclosed which comprises the steps of epitaxially growing on at least one surface of a single-crystal substrate a plurality of single-crystal semiconductor layers differing from each other in at least one of the kind and the concentration of an impurity, making porous the plurality of single-crystal semiconductor layers so as to form a high porosity layer and a low porosity layer, forming a non-porous single-crystal layer on a surface of the single-crystal semiconductor layer as made porous, and bonding and single-crystal substrate and a support substrate to each other, wherein the bonded single-crystal substrate and support substrate are separated at at least one of a location in the high porosity layer and an interface of the high porosity layer with a layer adjacent thereto.

Claims

1. A process of producing a semiconductor article comprising the steps of:

epitaxially growing on at least one surface of a single-crystal substrate a plurality of single-crystal semiconductor layers comprising a first single-crystal semiconductor layer and a second single-crystal semiconductor layer and differing from each other in at least one of the kind and the concentration of an impurity;

making porous the plurality of single-crystal semiconductor layers so as to form a high porosity layer in the first single-crystal semiconductor layer and a low porosity layer in the second single-crystal semiconductor layer;

subsequently forming a non-porous single-crystal layer on a surface of the single-crystal semiconductor layers as made porous; and

bonding the single-crystal substrate and a support substrate to each other,

wherein the bonded single-crystal substrate and support substrate are separated at at least one of a location in the high porosity layer and an interface of the high porosity layer with a layer adjacent thereto.

2. The process according to claim 1, wherein a plurality of single-crystal semiconductor layers differing from each other in at least one of the kind and the concentration of an impurity are again epitaxially grown on the single-crystal substrate obtained by removing the high porosity layer remaining on the side of the separated single-crystal substrate.

3. The process according to claim 1, wherein the single-crystal substrate is a semiconductor substrate.

4. The process according to claim 3, wherein the semiconductor substrate is a silicon substrate.

5. The process according to claim 1, wherein the low porosity layer is formed in the surface of the single-crystal semiconductor layer and the high porosity layer is formed under the low porosity layer.

6. The process according to claim 5, wherein the thickness of the low porosity layer is 20 μ

m or less.

7. The process according to claim 1, wherein a low impurity concentration layer is formed on the single-crystal substrate and a high impurity concentration layer is formed thereon.

8. The process according to claim 1, wherein the resistivity ρ

1 of the low porosity layer and the resistivity ρ

2 of the high porosity layer satisfy the relationship of ρ

1<

ρ

2.

9. The process according to claim 8, wherein the resistivity ρ

1 of the low porosity layer satisfies 0.001 Ω

cm<

ρ

1≦

0.1 Ω

cm.

10. The process according to claim 8, wherein the resistivity ρ

1 of the low porosity layer satisfies 0.005 Ω

cm<

ρ

1≦

0.02 Ω

cm.

11. The process according to claim 8, wherein the resistivity ρ

2 of the high porosity layer satisfies 0.02 Ω

cm<

ρ

2≦

10000 Ω

cm.

12. The process according to claim 8, wherein the resistivity ρ

2 of the high porosity layer satisfies 0.1 Ω

cm<

ρ

2≦

100 Ω

cm.

13. The process according to claim 1 or 2, wherein the separated single-crystal substrate is subjected to smoothing to be reutilized.

14. The process according to claim 13, wherein the smoothing is carried out after the step of removing the remaining high porosity layer.

15. The process according to claim 14, wherein the smoothing is a heat treatment in a reducing atmosphere comprising hydrogen.

16. The process according to claim 1, wherein the single-crystal semiconductor substrate is grown by chemical vapor deposition.

17. The process according to claim 1, wherein the bonding step comprises bonding the non-porous single-crystal layer and the support substrate to each other with an insulating layer therebetween.

18. The process according to claim 1, wherein the non-porous single-crystal layer is a semiconductor layer.

19. The process according to claim 18, wherein the semiconductor layer is a silicon layer.

20. The process according to claim 1, wherein the single-crystal substrate and the support substrate are separated by applying an external force to the bonded substrate.

21. The process according to claim 1, wherein the single-crystal substrate and the support substrate are separated by inserting into the bonded substrate at least one of a solid wedge and a fluid wedge.

22. The process according to claim 1, wherein the single-crystal substrate and the support substrate are separated by generating an internal stress in the bonded substrate.

23. The process according to claim 1, wherein the single-crystal substrate and the support substrate are separated by externally applying to the bonded substrate at least one of a thermal energy and an optical energy.

24. The process according to claim 1, wherein the single-crystal substrate and the support substrate are separated by jetting a fluid to a recess of the bonded substrate.

25. The process according to claim 1, wherein the single-crystal substrate and the support substrate are separated by attaching a jig to the bonded substrate and applying a mechanical force to the jig.

26. The process according to claim 1, wherein the separated single-crystal substrate is reutilized and subjected to the processing of the respective steps of claim 1 to produce a semiconductor article.

27. The process according to claim 1, wherein anodization is carried out such that the single-crystal semiconductor layer remains non-porous under the high porosity layer.

28. The process according to claim 1, wherein the thickness of the low porosity layer is different from that of the high porosity layer.

29. The process according to claim 5, wherein a porous layer with a porosity higher than the porosity of the high porosity layer is further formed under the high porosity layer.

30. The process according to claim 1, further comprising the step of heat treating the porous layer in an oxidizing atmosphere to form a protective film on the walls in the pores.

31. The process according to claim 1, further comprising the step of heat treating the porous layer in a reducing atmosphere comprising hydrogen, prior to the step of forming the non-porous single-crystal layer.

32. The process according to claim 1, wherein anodization is carried out while allowing a constant current to flow to thereby make the single-crystal semiconductor layer porous.

33. A process of producing a semiconductor article comprising the steps of:

epitaxially growing a single-crystal semiconductor layer on at least one surface of a single-crystal substrate;

making porous the single-crystal semiconductor layer to form a high porosity layer and a low porosity layer;

forming a non-porous single-crystal layer on a surface of the high porosity layer; and

bonding the single-crystal substrate and a support substrate to each other,

wherein the bonded single-crystal substrate and support substrate are separated at at least one of a location in the high porosity layer and an interface of the high porosity layer with a layer adjacent thereto.

34. The process according to claim 33, further comprising the step of oxidizing the inside wall surfaces of the high porosity layer and then removing an oxide film on the layer surface side.

35. A process of producing a semiconductor article comprising the steps of:

epitaxially growing a single-crystal semiconductor layer on at least one surface of a single-crystal substrate;

effecting heat treatment in a reducing atmosphere comprising hydrogen and then making porous the single-crystal semiconductor layer so as to form a high porosity layer and a low porosity layer;

forming a non-porous single-crystal layer on a surface of the high porosity layer; and

bonding the single-crystal substrate and a support substrate to each other,

wherein the bonded single-crystal substrate and support substrate are separated at at least one of a location in the high porosity layer and an interface of the high porosity layer with a layer adjacent thereto.

36. The process according to claim 35, wherein a low impurity concentration layer for forming the high porosity layer is formed by the heat treatment in the surface of the single-crystal semiconductor layer.