Patent ID: 7495275
Filing Date: 2009-02-24
Classification: H01L

Abstract:
1. A DRAM integrated circuit device that has a multi-layer wiring structure, comprising: a substrate that has a memory cell region and a peripheral circuit region formed thereon; a first interlayer insulating film that is formed on the substrate so as to collectively cover the memory cell region and the peripheral circuit region, the first interlayer insulating film covering a conductor pattern and a semiconductor element on the substrate; a polysilicon plug that penetrates the first interlayer insulating film in the memory cell region, and is in contact with a first diffusion region formed in the memory cell region; a second interlayer insulating film that is formed on the first interlayer insulating film so as to collectively cover the memory cell region and the peripheral circuit region, the second interlayer insulating film covering the polysilicon plug; a first wiring groove that is formed in the second interlayer insulating film in the memory cell region so as to cross over the polysilicon plug, said first wiring groove thereby exposing the polysilicon plug at a part of said first wiring groove that extends across said polysilicon plug; a first contact hole that is formed in the first wiring groove, penetrates the first interlayer insulating film, and exposes a conductive region that is formed in the peripheral circuit region on the substrate and has a smaller height than the polysilicon plug; a first wiring pattern that fills the first wiring groove including the first contact hole; a second wiring groove that is formed in the second interlayer insulating film in the peripheral circuit region; a second contact hole that is formed in the second wiring groove, penetrates the first interlayer insulating film, and exposes a second diffusion region that is formed in the peripheral circuit region; and a second wiring pattern that fills the second wiring groove including the second contact hole, the first wiring pattern and the second wiring pattern each having a principal surface located on the same plane as the principal surface of the second interlayer insulating film.