Method of forming via structures and method of fabricating phase change memory devices incorporating such via structures

Abstract

Provided are methods for forming conductive plug structures, such as via plugs, from a plurality of conductive layer patterns and methods of fabricating semiconductor devices, including semiconductor memory devices such as phase change semiconductor memory devices. An example method forms a small via structure by forming a conductive layer on a semiconductor substrate. A molding insulating layer is formed on the conductive layer and a via hole is formed through the insulating layer to expose a region of the conductive layer. A first via filling layer is formed and then partially removed to form a partial via plug. The formation and removal of the phase change material layer are then repeated as necessary to form a multilayer plug structure that substantially fills the via hole with the multilayer structure typically exhibiting reduced defects and damage than plug structures prepared by conventional methods.