Semiconductor structures including carrier wafers and methods of using such semiconductor structures
A semiconductor structure comprising a carrier wafer and a device wafer. The carrier wafer comprises trenches sized and configured to receive conductive pillars of the device wafer. The carrier wafer and the device wafer are fusion bonded together and back side processing effected on the device wafer. The device wafer may be released from the carrier wafer by one or more of mechanically cleaving, thermally cleaving, and mechanically separating. Methods of forming the semiconductor structure including the carrier wafer and the device wafer are disclosed.
1. A method comprising:
forming a device wafer, wherein forming the device wafer comprises acts of:
forming a dielectric material over an active surface of a first substrate; and
forming conductive pillars on the active surface of the first substrate;
forming a carrier wafer, wherein forming the carrier wafer comprises acts of:
forming trenches in a surface of a second substrate;
forming bonding surfaces on the surface of the second substrate;
forming stress cavities within the substrate proximate the bonding surfaces; and
forming a silicon nitride material over the bonding surfaces;
inserting the conductive pillars into the trenches; and
bonding the bonding surfaces of the carrier wafer with the dielectric material of the device wafer.
2. The method of claim 1 , wherein forming a dielectric material over an active surface of a first substrate comprises forming a dielectric material comprising silicon dioxide, silicon nitride, silicon oxynitride, tetraethyl orthosilicate, or borophosphosilicate.
3. The method of claim 1 , wherein forming trenches in a surface of a second substrate comprises forming the trenches to a depth greater than a height of the conductive pillars.
4. The method of claim 1 , wherein forming trenches in a surface of a second substrate comprises forming the trenches to a depth less than a height of at least some of the conductive pillars.
5. The method of claim 1 , wherein forming bonding surfaces on the surface of the second substrate comprises forming bonding surfaces that correspond to at least some portions of the active surface of the device wafer lacking conductive pillars.
6. The method of claim 1 , further comprising implanting hydrogen into regions of the carrier wafer proximate the bonding surfaces.
7. The method of claim 1 , wherein bonding the bonding surfaces of the carrier wafer with the dielectric material of the device wafer comprises temporarily attaching the device wafer to the carrier wafer without an adhesive.
8. The method of claim 1 , wherein bonding the bonding surfaces of the carrier wafer with the dielectric material of the device wafer comprises exposing the bonding surfaces of the carrier wafer to a plasma prior to bonding.
9. The method of claim 1 , wherein bonding the bonding surfaces of the carrier wafer with the dielectric material of the device wafer comprises exposing at least one of the active surface of the device wafer and the bonding surfaces of the carrier wafer to a plasma comprising at least one of oxygen, hydrogen, nitrogen, argon, and helium prior to bonding.
10. The method of claim 1 , wherein bonding the bonding surfaces of the carrier wafer with the dielectric material of the device wafer comprises exposing the carrier wafer and the device wafer to a temperature between about 200° C. and about 600° C.
11. The method of claim 1 , further comprising separating the device wafer from the carrier wafer.
12. A semiconductor structure, comprising:
a carrier wafer, comprising:
trenches within a surface of a semiconductor substrate;
bonding surfaces on the surface of the semiconductor substrate;
silicon nitride on the surface of the semiconductor substrate; and
stress cavities within the substrate proximate the bonding surfaces; and
a device wafer bonded to the carrier wafer, comprising:
conductive pillars on an active surface of the device wafer disposed within the trenches of the carrier wafer; and
a dielectric material over the active surface bonded to the bonding surfaces of the carrier wafer.
13. The semiconductor structure of claim 12 , wherein the bonding surfaces on the surface of the semiconductor substrate comprise at least one of silicon and silicon dioxide.
14. The semiconductor structure of claim 12 , further comprising hydrogen implanted regions in the semiconductor substrate proximate the bonding surfaces.
15. The semiconductor structure of claim 14 , wherein the hydrogen implanted regions in the semiconductor substrate further comprise at least one of helium and boron.
16. The semiconductor structure of claim 12 , further comprising at least another device wafer in contact with the device wafer bonded to the carrier wafer.
17. A method comprising:
forming a carrier wafer comprising trenches in a substrate and at least one bonding surface between at least some adjacent trenches of the trenches;
forming stress cavities in the at least one bonding surface of the carrier wafer;
forming support walls between at least other adjacent trenches of the trenches;
forming a device wafer comprising conductive elements protruding from a dielectric material overlying the device wafer;
inserting the conductive elements into the trenches of the carrier wafer and contacting the carrier wafer with the dielectric material while maintaining a gap between the support walls and the dielectric material of the device wafer;
bonding the device wafer to the carrier wafer at the at least one bonding surface;
removing a portion of the device wafer from a back side thereof; and
releasing the carrier wafer from the device wafer.
18. The method of claim 17 , wherein forming a carrier wafer comprises forming hydrogen implanted regions in the at least one bonding surface of the carrier wafer.
19. The method of claim 17 , wherein bonding the device wafer to the carrier wafer at the at least one bonding surface comprises masking the trenches of the carrier wafer, exposing the at least one bonding surface of the carrier wafer to a plasma, and contacting and heating the at least one bonding surface of the carrier wafer and the device wafer to fusion bond the device wafer and the carrier wafer.
20. The method of claim 17 , wherein releasing the carrier wafer from the device wafer comprises mechanically separating the carrier wafer from the device wafer.
21. The method of claim 17 , wherein releasing the carrier wafer from the device wafer comprises one of thermally cleaving or mechanically cleaving the carrier wafer from the device wafer.
22. A semiconductor structure, comprising:
a carrier wafer comprising stress cavities and trenches in a surface of a substrate and at least one bonding surface, the at least one bonding surface between at least some adjacent trenches of the trenches;
support walls between at least other adjacent trenches of the trenches;
a device wafer comprising a dielectric material, the dielectric material of the device wafer contacting the carrier wafer over the at least one bonding surface; and
a gap between the support walls and the dielectric material of the device wafer.
23. The semiconductor structure of claim 22 , further comprising a silicon oxide material over the at least one bonding surface of the carrier wafer.
24. The semiconductor structure of claim 22 , wherein the trenches extend farther into the carrier wafer than the stress cavities.
25. A semiconductor structure, comprising:
a carrier wafer comprising trenches in a surface of a substrate and at least one bonding surface, the at least one bonding surface between at least some adjacent trenches of the trenches;
support walls between at least other adjacent trenches of the trenches;
a silicon nitride material over at least a portion of the support walls and the at least one bonding surface;
a device wafer comprising a dielectric material, the dielectric material of the device wafer contacting the carrier wafer over the at least one bonding surface; and
a gap between the support walls and the dielectric material of the device wafer.
26. The semiconductor structure of claim 25 , wherein the silicon nitride material has a thickness between about 10 Å and about 100 Å.
27. The semiconductor structure of claim 25 , wherein the silicon nitride material is silicon rich.
28. A semiconductor structure, comprising:
a carrier wafer comprising trenches in a surface of a substrate and at least one bonding surface, the at least one bonding surface between at least some adjacent trenches of the trenches;
hydrogen implanted regions under the at least one bonding surface, at least some of the hydrogen implanted regions disposed above a lower surface of the trenches;
support walls between at least other adjacent trenches of the trenches;
a device wafer comprising a dielectric material, the dielectric material of the device wafer contacting the carrier wafer over the at least one bonding surface; and
a gap between the support walls and the dielectric material of the device wafer.
29. The semiconductor structure of claim 25 , further comprising a silicon oxide material over the silicon nitride material over the at least one bonding surface, the silicon oxide material extending further from a lower portion of the trenches than the silicon nitride material.