Semiconductor device with enhanced via or contact hole connection

Abstract

A semiconductor device has an interconnect layer, connected to a connecting region, such as a diffusion region or layer formed on the surface of a substrate, through a contact hole formed in an interlayer insulating film, which includes a concavity, representing a defective portion, extending from the bottom portion of the contact hole to the surface of the interconnect layer. This defective portion occurs because the metal comprising the interconnect layer will not penetrate to completely fill the contact hole. To correct for this formed defective portion, the concavity, the concavity is permitted to be formed followed by its filling with a plug electrode comprising a high quality penetration metal film, such as, tungsten. As a result, the mechanical as well as electrical characteristics of the interconnect layer connection to the connecting region is significantly improve by the presence of the plug electrode. In an alternative approach, both the interlayer insulating film and the interconnect layer comprising, for example, aluminum layer, may first be formed on the surface of the substrate followed by the selective etching to form concavities or contact holes within which are formed plug electrodes comprising, for example, a tungsten film for electrically connecting the interconnect layer to the diffusion layer through the plug electrode per se.