METHOD OF FORMING A CONTACT HOLE AND METHOD OF FORMING A PHASE CHANGE MEMORY DEVICE USING THE SAME

摘要

A method for forming a contact hole is provided to suppress generation of a seam or void in a material layer filled in a contact hole by forming a buffer layer on the inner surface of a preliminary contact hole formed in an interlayer dielectric made of a nitride material and an oxide material. An interlayer dielectric in which a first material and a second material different from the first material are stacked is formed on a substrate(100). The interlayer dielectric is partially etched to form an interlayer dielectric pattern(112) having a preliminary contact hole exposing the surface of the substrate. A protection spacer(118) is formed on the lateral surface of the interlayer dielectric pattern so that the lateral surface of the interlayer dielectric pattern exposed by the preliminary contact hole is not etched by a subsequent cleaning process. A native oxide layer formed on the surface of the exposed substrate is cleaned to form a contact hole having a smaller width than that of the preliminary contact hole. The first material is an oxide material, and the second material is a nitride material. The protection spacer is made of a nitride material.