Method of rounding a corner of a contact

摘要

The present invention provides a method for forming a contact opening having a rounded corner. Because the corner of the formed contact opening is rounded, a conductive material that is free of voids can be formed within the contact opening. In the present invention, a dielectric layer and a patterned photoresist layer are sequentially formed on a substrate. An isotropic etching process and a main etching process are performed to form a contact opening in the dielectric layer. A photoresist descum process is performed to remove a portion of the photoresist layer. Then, a soft etching process is performed to form a rounded corner on the top of the contact opening. The contact opening can be substantially filled with a conductive layer.