International Business Machines Corporation
Fully-aligned top-via structures with top-via trim

Abstract:

A method is presented for constructing fully-aligned top-via interconnects by employing a subtractive etch process. The method includes building a first metallization stack over a substrate, depositing a first lithography stack over the first metallization stack, etching the first lithography stack and the first metallization stack to form a receded first metallization stack, and depositing a first dielectric adjacent the receded first metallization stack. The method further includes building a second metallization stack over the first dielectric and the receded first metallization stack, depositing a second lithography stack over the second metallization stack, etching the second lithography stack and the second metallization stack to form a receded second metallization stack, and trimming the receded first metallization stack to form a via connecting the receded first metallization stack to the receded second metallization stack.