3D integrated circuit layer interconnect
A three-dimensional 3D interconnect structure with a small footprint is described, useful for connection from above to levels of circuit structures in a multi-level device. Also, an efficient and low cost method for manufacturing the 3D interconnect structure is provided.
1. A device comprising:
a three-dimensional structure including a plurality of levels, including levels 0 to N, where N is at least 2,
in which level (i), for (i) equal to 0 through N−1, includes a landing area (i) having a length in a longitudinal direction and a width in a transverse direction, and
in which level (i), for (i) equal to 1 through N, overlies level (i−1), and has an opening (i) which for (i) equal to 1 through N−1 is adjacent the landing area (i) on level (i), and extends over the landing area (i−1) on level (i−1) and for (i) greater than 1, over the opening (i−1) in level (i−1), the opening (i) having a distal longitudinal sidewall aligned with the distal longitudinal sidewall of opening (i−1) in level (i−1) and a proximal longitudinal sidewall defining a length of the opening (i) at least as large as the length of the landing area (i−1) plus the length of the opening (i−1), if any, and for (i) greater than 1, having transverse sidewalls aligned with the transverse sidewalls of opening (i−1) in level (i−1) and defining a width of the opening over landing area (i−1) at least as large as the width of landing area (i−1); and
insulating fill in the openings in levels 1 to N, and conductors extending through the insulating fill in the openings to contact the landing areas on levels 0 to N−1.
2. The device of claim 1 , wherein:
for (i) greater than 1, distal longitudinal sidewall of the opening (i) is self-aligned with the distal longitudinal sidewall of opening (i−1) in level (i−1); and
for (i) greater than 1, the transverse sidewalls of the opening (i) are self-aligned with the transverse sidewalls of opening (i−1) in level (i−1).
3. The device of claim 1 , wherein levels in the plurality of levels comprise conductive layers.
4. The device of claim 1 , further comprising a wiring layer overlying the plurality of levels including conductive lines contacting the conductors.
5. The device of claim 4 , wherein said conductive lines couple the plurality of levels to decoding circuitry.
6. The device of claim 1 , wherein levels in the plurality of levels include respective arrays of memory cells.
7. The device of claim 1 , wherein:
for (i) equal to 0 through N−1, level (i) includes an additional landing area (i) for contact with conductors; and
for (i) equal to 1 through N, level (i) has an additional opening (i) which for (i) equal to 1 through N−1 is adjacent the additional landing area (i) on level (i), and extends over the additional landing area (i−1) on level (i−1), and for (i) greater than 1, over the additional opening (i−1) in level (i−1).
8. The device of claim 7 , wherein for (i) equal to 1 through N−1, the landing area (i) and the additional landing area (i) are symmetrical about an axis perpendicular to both the longitudinal and transverse direction, and the opening (i) and additional opening (i) are symmetrical about said axis.