Metal contact structure in semiconductor device and method for forming the same

摘要

A metal contact structure of a semiconductor device and a method for forming the same are provided. The diameter of the upper portion of a contact hole that exposes a region of a lower conductive layer is formed to be larger than the diameter of the lower portion of the contact hole. The metal contact structure is formed without a void or a key hole. This is accomplished by forming at least two metal layers to fill the contact hole by performing a first deposition, an etch back, and a second deposition. The metal layer which fills the contact hole is etched back using a barrier metal layer formed on the entire surface of the contact hole as an etching stop layer. Thus, a void or key hole is not generated by making the upper portion of the contact hole to be wider than the lower portion of the contact hole and by depositing the metal which fills the contact hole through the processes of firstly depositing the metal, etching back the metal, and secondly depositing the metal.