Multilevel contact to a 3d memory array and method of making thereof

Abstract

A multi-level device includes at least one device region and at least one contact region. The contact region has a stack of alternating plurality of electrically conductive layers and plurality of electrically insulating layers located over a substrate. The plurality of electrically conductive layers form a stepped pattern in the contact region, where each respective electrically insulating layer includes a sidewall and a respective underlying electrically conductive layer in the stack extends laterally beyond the sidewall. Optionally, a plurality of electrically conductive via connections can be formed, which have top surfaces within a same horizontal plane, have bottom surfaces contacting a respective electrically conductive layer located at different levels, and are isolated from one another by at least one trench isolation structure.