Staged via formation from both sides of chip
A method of fabricating a semiconductor assembly can include providing a semiconductor element having a front surface, a rear surface, and a plurality of conductive pads, forming at least one hole extending at least through a respective one of the conductive pads by processing applied to the respective conductive pad from above the front surface, forming an opening extending from the rear surface at least partially through a thickness of the semiconductor element, such that the at least one hole and the opening meet at a location between the front and rear surfaces, and forming at least one conductive element exposed at the rear surface for electrical connection to an external device, the at least one conductive element extending within the at least one hole and at least into the opening, the conductive element being electrically connected with the respective conductive pad.
1. A semiconductor assembly, comprising:
a semiconductor element having a front surface, a rear surface remote from the front surface, an opening extending from the rear surface partially through a thickness of the semiconductor element, a plurality of conductive pads at the front surface, and a plurality of holes each extending through a respective one of the conductive pads and partially through the thickness of the semiconductor element, each of the holes meeting the opening at a respective location between the front and rear surfaces, wherein at the location where each of the holes and the opening meet, interior surfaces of the respective hole and the opening extend at different angles relative to the rear surface such that there is a step change between slopes of the interior surfaces of the respective hole and the opening;
a continuous dielectric layer overlying an interior surface of the respective one of the conductive pads within each of the holes and overlying an interior surface of the semiconductor material within each of the holes;
a plurality of conductive interconnects each extending into the opening and exposed at the rear surface for electrical connection with an external device; and
a plurality of conductive vias each extending within a respective one of the holes and extending between a respective one of the conductive interconnects and a respective one of the conductive pads, each of the conductive vias having a portion overlying the continuous dielectric layer.
2. The semiconductor assembly as claimed in claim 1 , wherein each of the conductive interconnects overlies at least an inner surface of the opening and conforms to a contour of the inner surface.
3. The semiconductor assembly as claimed in claim 2 , wherein each of the conductive interconnects extends along a respective portion of the inner surface of the opening.
4. The semiconductor assembly as claimed in claim 2 , wherein each of the conductive interconnects defines an internal space.
5. The semiconductor assembly as claimed in claim 4 , wherein each of the internal spaces is at least partially filled with a dielectric material.
6. The semiconductor assembly as claimed in claim 2 , further comprising a dielectric layer overlying at least the inner surface of the opening, wherein each of the conductive interconnects fills a respective volume between surfaces of the dielectric layer.
7. The semiconductor assembly as claimed in claim 1 , wherein at least one of the conductive vias overlies at least an inner surface of the respective one of the holes, the conductive via conforming to a contour of the hole.
8. The semiconductor assembly as claimed in claim 7 , wherein each of the at least one of the conductive vias defines an internal space.
9. The semiconductor assembly as claimed in claim 8 , wherein each of the internal spaces is at least partially filled with a dielectric material.
10. The semiconductor assembly as claimed in claim 7 , further comprising a dielectric layer overlying at least the inner surface of the respective one of the holes, wherein each of the at least one of the conductive vias fills a volume between surfaces of the dielectric layer.
11. A semiconductor assembly, comprising:
a semiconductor element having a front surface, a rear surface remote from the front surface, an opening extending from the rear surface partially through a thickness of the semiconductor element, a plurality of conductive pads at the front surface, and a plurality of holes each extending through a respective one of the conductive pads and partially through the thickness of the semiconductor element, each of the holes meeting the opening at a respective location between the front and rear surfaces, wherein at the location where each of the holes and the opening meet, interior surfaces of the respective hole and the opening extend at different angles relative to the rear surface such that there is a step change between slopes of the interior surfaces of the respective hole and the opening;
a continuous dielectric layer overlying an interior surface of the respective one of the conductive pads within each of the holes and overlying an interior surface of the semiconductor material within each of the holes; and
a plurality of conductive interconnects each having a first portion exposed at the rear surface for electrical connection with an external device and a second portion overlying the continuous dielectric layer, each of the conductive interconnects extending within a respective one of the holes and into the opening, each of the conductive interconnects extending to a respective one of the conductive pads.
12. The semiconductor assembly as claimed in claim 11 , further comprising a dielectric region disposed within one of the holes and the opening and an aperture extending through the dielectric region, the aperture having a contour not conforming to either a contour of the one of the holes or a contour of the opening, wherein a respective one of the conductive interconnects extends at least within the aperture.
13. The semiconductor assembly as claimed in claim 12 , wherein the respective one of the conductive interconnects has a cylindrical or frusto-conical shape.
14. The semiconductor assembly as claimed in claim 11 , wherein the opening has a channel shape having a length extending in a first direction along a surface of the semiconductor element, and a width extending a second lateral direction transverse to said first direction, the length being greater than the width.
15. A semiconductor assembly, comprising:
a semiconductor element having a front surface, a rear surface remote from the front surface, an opening extending from the rear surface at least partially through the thickness of the semiconductor element, and first and second holes each extending from the front surface partially through the thickness of the semiconductor element, each of the first and second holes and the opening meeting at a respective location between the front and rear surfaces;
a plurality of conductive pads at the front surface;
a first conductive element having a portion exposed at the rear surface for electrical connection with an external device, the first conductive element extending within the first hole to a first one of the conductive pads and at least into the opening; and
a second conductive element having a portion exposed at the rear surface for electrical connection with the external device, the second conductive element extending within the second hole to a second one of the conductive pads and at least into the opening.
16. The semiconductor assembly as claimed in claim 15 , wherein each conductive element includes a conductive interconnect and a conductive via, each conductive interconnect exposed at the rear surface for electrical connection to an external device and extending at least into the opening, each conductive via extending within the respective hole and coupled to the respective conductive interconnect and the respective one of the conductive pads.
17. The semiconductor assembly as claimed in claim 16 , wherein each conductive via overlies at least an inner surface of the respective hole, each conductive via conforming to a contour of the respective hole.
18. The semiconductor assembly as claimed in claim 17 , wherein each conductive via defines an internal space.
19. The semiconductor assembly as claimed in claim 18 , wherein each internal space is at least partially filled with a dielectric material.