Semiconductor memory with insulation film embedded in groove formed on

Abstract

A semiconductor memory having memory cells is formed on a semiconductor substrate. Each of the memory cells has a transistor and a capacitor. The transistor includes a channel region, a drain region and a source region aligned in a line and being insulated by an insulation film from an adjacent cell. Each of the memory cells has a gate electrode formed on the channel region with a gate insulating film therebetween. A pad electrode makes electrical contact with one of the source and drain regions of the memory cell and extends over the insulation film. A bit line makes electrical contact with the pad electrode above, extends in parallel to the line and is laterally isolated from one of the source and drain regions. A first insulating film is formed on the semiconductor substrate over the bit line. A first capacitor electrode is formed on the first insulating film, making electrical contact with the other of the source and drain regions of the memory cell through a contact hole opened through the first insulating film and insulated from the bit line by the first insulating film. A second capacitor electrode is formed on the first capacitor electrode with a second insulating film provided therebetween. The insulation film is embedded in a groove formed on the semiconductor substrate.