Multiheight electrically conductive via contacts for a multilevel interconnect structure

摘要

A method of making multi-level contacts includes providing an in-process multilevel device having a device region and a contact region including a stack of a plurality of alternating sacrificial layers and insulator layers located over a major surface of a substrate. A contact mask with at least one contact mask opening and at least one first terrace mask opening is provided over the stack, where the at least one first terrace mask opening is larger than the at least one contact mask opening. At least one first contact opening and at least one first terrace opening are simultaneously formed extending substantially perpendicular to the major surface of the substrate through the stack to a first sacrificial layer by etching a portion of the stack through the at least one contact mask opening and the at least one first terrace mask opening. A first electrically conductive via contact is deposited in the at least one first contact opening.

主权项

1. A method of making multi-level contacts, comprising:
providing an in-process multilevel device comprising a device region and a contact region comprising a stack of plurality of alternating sacrificial layers and insulating layers located over a major surface of a substrate; providing a first contact mask with at least one first contact mask opening and at least one first terrace mask opening over the stack, wherein the at least one first terrace mask opening is larger than the at least one first contact mask opening; simultaneously forming at least one first contact opening and at least one first terrace opening extending substantially perpendicular to the major surface of the substrate through the stack to a first sacrificial layer by etching a portion of the stack through the at least one first contact mask opening and the at least one first terrace mask opening; detecting an end point of the etching when the at least one terrace opening reaches the first sacrificial layer and stopping the etching of the stack to form both the at least one first contact opening and at least one first terrace opening when the end point of the etching is detected; removing the first contact mask; providing a second contact mask with at least one second contact mask opening and at least one second terrace mask opening over the stack, wherein the at least one second terrace mask opening is larger than the at least one second contact mask opening; simultaneously forming at least one second contact opening and at least one second terrace opening extending substantially perpendicular to the major surface of the substrate through the stack to a second sacrificial layer by etching a portion of the stack through the at least one second contact mask opening and the at least one second terrace mask opening; depositing a first electrically conductive via contact in the at least one first contact opening; and depositing a second electrically conductive via contact in the at least one second contact opening.