Method for forming metal wiring layer of semiconductor device

摘要

A method for forming a metal wiring layer of a semiconductor device, where a first layer having a recess region is formed on a semiconductor substrate. A second layer is formed on inner walls of the recess region and on an upper portion of the first layer. A third layer is formed on the second layer so as to have a smaller third layer thickness on the inner walls of the recess region than on the upper portion of the first layer. A fourth layer is then formed on the-third layer, providing a metal wiring layer with improved step coverage.