Method for separating two elements and a device therefor

• US 6,821,376 B1
• Filed: 01/08/2002
• Issued: 11/23/2004
• Est. Priority Date: 07/12/1999
• Status: Expired due to Term

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Aspar, Bernard, Moriceau, Hubert, Rayssac, Olivier, Montmayeul, Philippe
• Primary Examiner(s): Osele, Mark A.
• Application Number:
  US10/030,272
• Time in Patent Office: 1,050 Days
• Field of Search: 156/344, 156/584, 156/382, 438/455, 438/458, 294/261, 294/262, 294/264, 294/265, 292/39
• US Class Current: 156/701
• CPC Class Codes: H01L 21/67092 Apparatus for mechanical treatment or grinding or cutting, see the relevant groups in subclasses B24B or B28D
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 2221/68318 Auxiliary support including means facilitating the separation of a device or wafer from the auxiliary support
• CPC Class Codes: H01L 2221/68327 used during dicing or grinding
• CPC Class Codes: H01L 2221/68368 used in a transfer process involving at least two transfer steps, i.e. including an intermediate handle substrate
• CPC Class Codes: Y10S 156/941 Means for delaminating semiconductive product
• CPC Class Codes: Y10T 156/11 Methods of delaminating, per se; i.e. , separating at bonding face
• CPC Class Codes: Y10T 156/1111 Using solvent during delaminating [e.g., water dissolving adhesive at bonding face during delamination, etc.]
• CPC Class Codes: Y10T 156/19 Delaminating means
• CPC Class Codes: Y10T 29/49822 by applying force
• CPC Class Codes: Y10T 29/53683 Spreading parts apart or separating them from face to face engagement

Abstract

A process and device for separating two semi-conductor substrate wafers along an interface. The process includes forming a cavity, and initiating separation by applying force to the interface through the cavity. The device utilizes fluid or gas, and pressure chambers, to subject adherent faces of the interface to at least one of chemical or mechanical action.

Claims

1. A process for separating two semi-conductor substrate wafers alone an interface including all points of contact between the wafers, both wafers bonded to one another at adherent faces of the interface, the process comprising:

forming at least one cavity in at least one of the wafers, the cavity providing access of separation means to at least one predetermined zone of the interface;

initiating separation of the wafers along the interface by applying the separation means to the predetermined zone; and

continuing separation of the wafers along the interface, by applying the separation means to the predetermined zone and to separated portions of the interface, until a desired degree of separation is achieved,

wherein points of entry to the cavity are not located solely at an edge surface of the wafers.

2. The process of claim 1, in which the separation of the two wafers is induced in more than one predetermined zone, in a simultaneous or sequential manner.

3. The process of claim 1, wherein the separation means contains means for exerting a mechanical action at the interface.

4. The process of claim 1, wherein the separation means contains means for exerting a chemical action on at least one of the wafers at the interface.

5. The process of claim 1, wherein the cavity is obtained, in whole or in part, by engraving.

6. The process of claim 1, in which the cavity is made at a periphery of at least one of the wafers and provides access of the separation means to the the adherent faces.

7. The process of claim 1, wherein the cavity is made in an inner region of at least one of the wafers and does not provide access of the separation means to the adherent faces.

8. The process of claim 7, wherein the separation means contains a liquid, the process further comprising using microwaves to excite the liquid of the separation means.

9. The process of claim 1, wherein the cavity penetrates through at least one wafer from side to side.

10. The process of claim 1, wherein several predetermined zones are planned and are arranged so as to initiate the separation at determined locations of the interface.

11. The process of claim 1, wherein the two wafers adhere to one another with a different adherence energy in different regions of the adherent faces, so as to initiate separation at a determined location of the adherent faces.

12. The process of claim 1, for separating two wafers having a first interface formed at the adherent faces and a second interface interface in which the separation of the wafers is induced at one of the first and second interfaces.

13. The process of claim 12, wherein a bonding energy of the second interface is lower than a bonding energy of the first interface, and wherein the separation of the wafers is induced in the second interface.

14. The process of claim 12, in which, before the two wafers are brought into contact, an embrittled zone is formed in at least one of the two wafers at the second interface.

15. The process of claim 14, in which the embrittled zone is formed using an implantation technique or using a layer adherence technique.

16. The process of claim 15, in which the embrittled zone is formed at a shallow depth in one of the wafers such that the second interface delimits a thin layer in the wafer containing the embrittled zone.

17. The process of claim 1, wherein the wafers comprise a first wafer and a second wafer, the first wafer being at most 100 micrometers thick and the second wafer being used as a handle for the first wafer.

18. The process of claim 1, wherein the cavity is formed in the second wafer.

19. The process of claim 1, wherein the cavity is formed before the wafers are bonded to one another.

20. A device for separating two semi-conductor substrate wafers along an interface including all points of contact between the wafers, both wafers bonded to one another at adherent faces of the interface, at least one wafer including a cavity extending to at least one of the adherent faces, points of entry to the cavity not being located solely at an edge surface of the wafers, the device comprising:

fluid or gas for subjecting the at least one of the adherent faces to at least one of a chemical or mechanical action;

an enclosure with at least one high-pressure chamber configured to receive the fluid or gas; and

at least one low-pressure chamber,

wherein the enclosure is formed so as to receive the two wafers such that the cavity communicates with the high-pressure chamber.

21. The device of claim 20, wherein the holding means comprises at least one joint arranged between one of the wafers and a wall of the enclosure.

22. The device of claim 21, in which at least one joint is arranged between a main face of at least one of the wafers in a form of a plate and a wall of the enclosure facing the main face.

23. The device of claim 21, in which at least one joint is arranged between an edge of at least one of the wafers in a form of a plate and a wall of the enclosure facing the edge.

24. The device of claim 20, wherein the wafers comprise a first wafer and a second wafer, the first wafer being at most 100 micrometers thick and the second wafer being used as a handle for the first wafer.

25. The device of claim 20, wherein the cavity is formed in the second wafer.

26. The device of claim 20, wherein the cavity is formed before the wafers are bonded to one another.

27. A process for separation of first and second wafers, the two wafers bonded by adherent faces of an interface including all points of contact between the first and second wafers, the second wafer including at least one cavity formed in an interface portion of the second wafer so as to extend onto the interface and to face an interface portion of the first wafer, the process comprising:

inserting separation means into the cavity, the separation means comprising a liquid or a gas and inducing a higher pressure within the cavity;

inducing a lower pressure within a chamber bounded, in part, by at least one of the two wafers; and

preventing excessive deformation of at least one of the two wafers, by providing a stopper within the chamber having the lower pressure.

28. The process of claim 27, in which the separation of the two wafers is induced in one or more of the interface portions, in a simultaneous or sequential manner.

29. The process of claim 27, wherein the separation means further comprises means for exerting a mechanical action at the interface.

30. The process of claim 27, wherein the separation means further comprises means for exerting a chemical action on at least one of the wafers at the interface.

31. The process of claim 27, wherein the cavity is obtained, in whole or in part, by engraving.

32. The process of claim 27, in which the cavity is made at a periphery of at least one of the wafers and permits access of the separation means to the adherent faces.

33. The process of claim 27, wherein the cavity is made in an inner region of at least one of the wafers and does not permit access of the separation means to the adherent faces.

34. The process of claim 33, wherein the separation means contains a liquid, the process further comprising using microwaves to excite the liquid of the separation means.

35. The process of claim 27, wherein the cavity penetrates through at least one wafer from side to side.

36. The process of claim 27, wherein several cavities are planned and are arranged so as to initiate the separation at determined locations of the interface.

37. The process of claim 27, wherein the two wafers adhere to one another with a different adherence energy in different regions of the adherent faces, so as to initiate separation at a determined location of the adherent faces.

38. The process of claim 27, for separating two wafers having at least a first interface portion formed at the adherent faces and at least one second interface portion, in which the separation of the wafers is induced at one of the first and second interface portions.

39. The process of claim 38, wherein a bonding energy in the second interface portion is lower than a bonding energy of the first interface portion, and wherein the separation of the wafers is induced in the second interface portion.

40. The process of claim 38, in which, before the two wafers are brought into contact, an embrittled zone is formed in at least one of the two wafers at the second interface portion.

41. The process of claim 40, in which the embrittled zone is formed using an implantation technique or using a layer adherence technique.

42. The process of claim 41, in which the embrittled zone is formed at a shallow depth in one of the wafers such that the second interface portion delimits a thin layer in the wafer containing the embrittled zone.