Method for forming interlayer connectors to a stack of conductive layers

A method, for use with an integrated circuit device including a stack comprising a plurality of conductive layers interleaved with a plurality of dielectric layers, for forming interlayer connectors extending to respective ones of the plurality of conductive layers, the method comprising:

• removing portions of the conductive layers and the dielectric layers in the stack to form landing areas on the plurality of conductive layers in the stack, the landing areas without overlying conductive layers in the stack, wherein said removing includes using a set of M etch masks with M being greater than or equal to 2, and with NM being less than or equal to W, the etch masks having mask regions and spaced apart open etch regions corresponding to selected landing areas, wherein W is the number of total conductive layers;
• for each etch mask m, where m goes from 0 to M−1, etching Nm conductive layers over up to 1/N of the landing areas, trimming the etch mask m, and etching Nm conductive layers over up to 1/N of the landing areas, so that the landing areas on the plurality of conductive layers are exposed with different combinations of the etch masks.

A set of etch masks for use in exposing landing areas on a plurality of conductive layers interleaved with a plurality of dielectric layers comprising:

• a set of M etch masks, the etch masks having mask regions and spaced apart open etch regions, where M is an integer greater than or equal to 2 and N is an integer greater than or equal to 3;
• for each etch mask m in the set, where m goes from 0 to M−1, the etch mask covers landing areas on Nm+1 of the conductive layers and the open etch region covers landing areas on Nm of the conductive layers.