Forming vias and trenches for self-aligned contacts in a semiconductor structure

摘要

A semiconductor structure is formed to include a non-conductive layer with at least one metal line, a first dielectric layer, a first stop layer, a second dielectric layer, a second stop layer, a third stop layer and a fourth stop layer. A first photoresist layer is formed over the upper stop layer to develop at least one via pattern. The structure is selectively etched to form the via pattern in the third stop layer through the fourth stop layer. The first photoresist layer is then removed. A second photoresist layer is formed over the upper stop layer to develop a plurality of trench patterns, each of the trench pattern comprising a via-trench portion in which the trench pattern is formed above the via pattern, and a trench portion that is remaining part of the trench pattern.

主权项

1. A method to form trenches and vias in a semiconductor structure, the method comprising:
forming a structure including a non-conductive layer with at least one metal line, a first dielectric layer formed over the non-conductive layer, a first etch stop layer formed over the first dielectric layer, a second dielectric layer formed over the first etch stop layer, and an upper etch stop layer formed over the second dielectric layer; forming a first photoresist layer over the upper etch stop layer to develop at least one via pattern; patterning the first photoresist layer selectively to form the at least one via pattern in the upper stop layer; removing the first photoresist layer; forming a second photoresist layer over the upper etch stop layer to develop at least one trench pattern, the trench pattern comprising a via-trench portion in which the trench pattern is formed above the via pattern and a trench portion that is a remaining part of the trench pattern other than the via-trench portion; and etching the structure until the via-trench portion reaches the metal line in the non-conductive layer.