Semiconductor structures including carrier wafers and attached device wafers, and methods of forming 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 semiconductor structure, comprising:
a carrier wafer comprising:
trenches in a substrate;
support walls between adjacent trenches;
hydrogen implanted regions under a surface of the substrate; and
an oxide material over the carrier wafer; and
at least one device wafer coupled to the carrier wafer, the at least one device wafer comprising:
conductive elements disposed in the trenches; and
a conductive via extending from each conductive element to a conductive pad structure on a side of the at least one device wafer opposite a side of the conductive elements.
2. The semiconductor structure of claim 1 , further comprising conductive elements of another device wafer in electrical communication with conductive pads of the at least one device wafer.
3. The semiconductor structure of claim 2 , further comprising a dielectric material between the at least one device wafer and the another device wafer.
4. The semiconductor structure of claim 1 , further comprising a silicon nitride material disposed between the at least one device wafer and the carrier wafer.
5. The semiconductor structure of claim 1 , further comprising a dielectric material over surfaces of the at least one device wafer.
6. The semiconductor structure of claim 1 , further comprising a gap between the support walls and a surface of the at least one device wafer.
7. The semiconductor structure of claim 1 , wherein the oxide material over the carrier wafer overlies a silicon nitride material.
8. The semiconductor structure of claim 1 , further comprising at least one of helium or boron in the hydrogen implanted regions.
9. A method of forming a semiconductor structure, the method comprising:
forming a carrier wafer, forming the carrier wafer comprising:
forming trenches in a substrate;
forming support walls between adjacent trenches;
implanting hydrogen into a surface of the carrier wafer to form hydrogen implanted regions; and
forming an oxide material over the carrier wafer;
disposing conductive elements of at least one device wafer in the trenches of the carrier wafer, each conductive element in electrical communication with a conductive via extending through the at least one device wafer to a conductive pad structure on a side of the at least one device wafer opposite a side of the conductive elements; and
bonding the carrier wafer to the at least one device wafer.
10. The method of claim 9 , further comprising implanting at least one of helium or boron into the hydrogen implanted regions.
11. The method of claim 9 , further comprising electrically coupling the conductive pad structure of the at least one device wafer to conductive elements of another device wafer.
12. The method of claim 9 , further comprising forming a silicon nitride material over the carrier wafer prior to forming the oxide material over the carrier wafer.
13. The method of claim 9 , wherein disposing conductive elements of at least one device wafer in the trenches comprises maintaining a gap between the support walls and a surface of the at least one device wafer.
14. The method of claim 9 , further comprising exposing the hydrogen implanted regions to heat to release the carrier wafer from the at least one device wafer.
15. A method comprising:
forming a device wafer, wherein forming the device wafer comprises:
forming a dielectric material over an active surface of a first substrate;
forming conductive vias extending through the device wafer;
forming conductive pillars on the active surface of the first substrate and in electrical communication with the conductive vias; and
forming conductive pad structures in electrical communication with the conductive vias on an opposite side of the first substrate;
disposing at least another device wafer on a side of the device wafer opposite the active surface;
forming a carrier wafer, wherein forming the carrier wafer comprises:
forming trenches in a surface of a second substrate and leaving support walls between adjacent trenches;
implanting hydrogen into a surface of the carrier wafer to form hydrogen implanted regions and doping the hydrogen implanted regions with at least one of helium and boron; and
forming at least one bonding surface on a portion of the surface of the second substrate;
inserting the conductive pillars into the trenches and maintaining a gap between the support walls of the carrier wafer and the active surface of the device wafer; and
bonding the at least one bonding surface of the carrier wafer with the dielectric material of the device wafer.
16. The method of claim 15 , further comprising:
removing material from a back side of the device wafer; and
releasing the carrier wafer from the device wafer comprising at least one of cleaving the carrier wafer at hydrogen implanted regions or stress cavities in the carrier wafer.
17. The method of claim 16 , wherein releasing the carrier wafer from the device wafer further comprises separating the carrier wafer from the device wafer while leaving a silicon nitride material on surfaces of the device wafer.
18. The method of claim 16 , further comprising forming stress cavities in at least one surface of the carrier wafer.
19. A semiconductor structure, comprising:
a carrier wafer comprising:
trenches in a substrate;
support walls between adjacent trenches; and
hydrogen implanted regions in the substrate, the hydrogen implanted regions doped with at least one of helium and boron;
a device wafer bonded to the carrier wafer, the device wafer comprising:
conductive vias extending through the device wafer;
conductive pillars in electrical communication with the conductive vias on a first side of the device wafer; and
conductive pad structures in electrical communication with the conductive vias on a second, opposite side of the device wafer,
a gap between the support walls and the second side of the device wafer; and
at least another device wafer on a side of the device wafer opposite a side of the carrier wafer.
20. The semiconductor structure of claim 1 , wherein the surfaces of the support walls between the carrier wafer and the device wafer are free of the oxide material.
21. The semiconductor structure of claim 1 , wherein the hydrogen implanted regions comprise regions located below lower surfaces of the trenches and regions located above the lower surfaces of the trenches.