A three-dimensional stacked IC device has a stack of contact levels at an interconnect region. According to some examples of the present invention, it only requires a set of N etch masks to create up to and including 2N levels of interconnect contact regions at the stack of contact levels. According to some examples, 2x−1 contact levels are etched for each mask sequence number x, x being a sequence number for the masks so that for one mask x=1, for another mask x=2, and so forth through x=N. Methods create the interconnect contact regions aligned with landing areas at the contact levels.