Method for manufacturing bonded wafer and bonded wafer manufactured thereby

• US 6,004,866 A
• Filed: 02/28/1997
• Issued: 12/21/1999
• Est. Priority Date: 03/18/1996
• Status: Expired due to Fees

• Current Assignee: Shin-Etsu Handotai Co., Ltd. (Shin-Etsu Chemical Company Limited)
• Original Assignee: Shin-Etsu Handotai Co., Ltd. (Shin-Etsu Chemical Company Limited)
• Inventors: Sakai, Masahiro, Mitani, Kiyoshi, Nakano, Masatake
• Primary Examiner(s): DUTTON, BRIAN KEITH
• Application Number:
  US08/808,655
• Time in Patent Office: 1,026 Days
• Field of Search: 451/285, 451/286, 451/287, 451/288, 451/289, 438/455, 438/459, 438/691, 438/692
• US Class Current: 438/459
• CPC Class Codes: H01L 21/187 by direct bonding
• CPC Class Codes: H01L 21/2007 Bonding of semiconductor wafers to insulating substrates or to semiconducting substrates using an intermediate insulating layer H01L21/2011 takes precedence; bonding of semiconductor wafers to semiconductor wafers for junction formation H01L21/187

Abstract

A method for manufacturing a bonded wafer comprises the steps of; mirror-polishing a surface of first and second substrates, bringing the mirror-polished surfaces of the substrates contact with each other to join them, and subjecting the substrates to a heat treatment to firmly bond them. One of the surfaces of the first and second substrates prior to bonding, or one surface of the bonded wafer is subjected to a polishing treatment for exerting little influence by irregularities on a rear surface of the one substrate or by a figure of a surface of a polishing plate which is in contact with the rear surface of the one substrate.

Claims

1. A method for manufacturing a bonded wafer comprising the steps of:

mirror-polishing a surface of a first substrate;

mirror-polishing a surface of a second substrate;

joining the mirror-polished surfaces of the first and second substrates together; and

applying a heat treatment to the first and second substrates to bond the first and second substrates together,

wherein at least one of the two mirror-polishing steps of the surfaces of the first and second substrates is performed by a polishing treatment that prevents the occurrence of peels on a front surface of either one of the first and second substrates having the mirror-polished surface either by existing irregularities on a rear surface of the either one of the first and second substrates having the mirror-polished surface and by a figure of a surface of a polishing plate which is in contact with the rear surface of the either one of the first and second substrates having the mirror-polished surface.

2. The method for manufacturing a bonded wafer according to claim 1, wherein both the first and second substrates comprise silicon.

3. The method for manufacturing a bonded wafer according to claim 1, wherein the polishing treatment is performed by a polishing method in which the either one of the first and second substrates having the mirror-polished surface is held without fixing the rear surface to the polishing plate.

4. The method for manufacturing a bonded wafer according to claim 3, wherein the polishing method is one of either a double side polishing method and a polishing method in which the rear surface of the either one of the first and second substrates having the mirror-polished surface is held on a non-rigid absorption surface of a holding member to absorb the irregularities on the rear surface of the either one of the first and second substrates having the mirror-polished surface.

5. The method for manufacturing a bonded wafer according to claim 3, wherein the polishing method is one in which the front surface of the either one of the first and second substrates having the mirror-polished surface is polished with a polishing pad while the rear surface of the either one of the first and second substrates having the mirror-polished surface is held in a hole of a substrate supporting member having a diameter larger than that of the either one of the first and second substrates having the mirror-polished surface without fixing the rear surface of the either one of the first and second substrates having the mirror-polished surface to the substrate supporting member.

6. A method for manufacturing a bonded wafer comprising the steps of:

mirror-polishing a surface of the first substrate;

mirror-polishing a surface of the second substrate;

forming an insulating film on at least one of the mirror-polished surfaces of the first and second substrates;

joining the mirror-polished surfaces of the first and second substrates together with the insulating film between the mirror-polished surfaces of the first and second substrates; and

applying a heat treatment to the first and second substrates to bond the first and second substrates together,

wherein at least one of the two mirror-polishing steps of the surfaces of the first and second substrates is performed by a polishing treatment that prevents the occurrence of peels on a front surface of either one of the first and second substrates having the mirror-polished surface either by existing irregularities on a rear surface of the either one of the first and second substrates having the mirror-polished surface and by a figure of a surface of a polishing plate which is in contact with the rear surface of the either one of the first and second substrates having the mirror-polished surface.

7. The method for manufacturing a bonded wafer according to claim 6, wherein both the first and second substrates comprise silicon.

8. The method for manufacturing a bonded wafer according to claim 6, wherein the polishing treatment is performed by a polishing method in which the either one of the first and second substrates having the mirror-polished surface is held without fixing the rear surface to the polishing plate.

9. The method for manufacturing a bonded wafer according to claim 8, wherein the polishing method is one of either a double side polishing method and a polishing method in which the rear surface of the either one of the first and second substrates having the mirror-polished surface is held on a non-rigid absorption surface of a holding member to absorb the irregularities on the rear surface of the either one of the first and second substrates having the mirror-polished surface.

10. The method for manufacturing a bonded wafer according to claim 8, wherein the polishing method is one in which the front surface of the either one of the first and second substrates having the mirror-polished surface is polished with a polishing pad while the rear surface of the either one of the first and second substrates having the mirror-polished surface is held in a hole of a substrate supporting member having a diameter larger than that of the either one of the first and second substrates having the mirror-polished surface without fixing the rear surface of the either one of the first and second substrates having the mirror-polished surface to the substrate supporting member.

11. The method for manufacturing a bonded wafer according to claim 6 further comprising the steps of:

thinning one of the bonded substrates by one of wet-etching and grinding; and

polishing the thinned substrate.

12. The method for manufacturing a bonded wafer according to claim 6 further comprising the steps of:

thinning one of the bonded substrates by one of wet-etching and grinding;

polishing the thinned substrate; and

further thinning the polished and thinned substrate by vapor-phase etching to form a thin semiconductor layer.

13. The method for manufacturing a bonded wafer according to claim 12, wherein the step of further thinning the polished and thinned substrate by vapor-phase etching comprises measuring a thickness distribution of the polished and thinned substrates that is to be made thinner to make a map of the thickness distribution, and locally thinning a thicker portion of the one of the bonded substrates on the basis of the map by vapor phase etching, which is numerically controlled.

14. A method for manufacturing a bonded wafer comprising the steps of:

mirror-polishing a surface of a first substrate;

mirror-polishing a surface of a second substrate;

forming an insulating film on at least one of the mirror-polished surfaces of the first and second substrates;

joining the mirror-polished surfaces of the first and second substrates together with the insulating film between the mirror-polished surfaces of the first and second substrates;

applying a heat treatment to the first and second substrates to bond the first and second substrates together;

thinning the first substrate of the bonded substrates by one of wet-etching and grinding; and

subjecting the thinned first substrate of the bonded substrates to a polishing treatment that prevents the occurrence of peels on a front surface of the thinned first substrate either by existing irregularities on a rear surface of the second substrate and by a figure of a surface of a polishing plate which is in contact with the rear surface of the second substrate.

15. The method for manufacturing a bonded wafer according to claim 14, wherein both the first and second substrates comprise silicon.

16. The method for manufacturing a bonded wafer according to claim 14, wherein the polishing treatment is performed by a polishing method in which the second substrate is held without fixing the rear surface to the polishing plate.

17. The method for manufacturing a bonded wafer according to claim 16, wherein the polishing method is one of either a double side polishing method and a polishing method in which the rear surface of the second substrate is held on a non-rigid absorption surface of a holding member to absorb the irregularities on the rear surface of the second substrate.

18. The method for manufacturing a bonded wafer according to claim 16, wherein the polishing method is one in which the front surface of the thinned first substrate is polished with a polishing pad while the rear surface of the second substrate is held in a hole of a substrate supporting member having a diameter larger than that of the second substrate.

19. The method for manufacturing a bonded wafer according to claim 14 further comprising the steps of:

further thinning the first substrate thinned by one of wet-etching and grinding; and

polishing the first substrate by vapor-phase etching.

20. The method for manufacturing a bonded wafer according to claim 19, wherein the step of further thinning the first substrate by vapor-phase etching comprises measuring a thickness distribution of the first substrate to be previously made thinner to make a map of the thickness distribution, and locally thinning a thicker portion of the first substrate on the basis of the map by vapor phase etching which is numerically controlled.