Patent ID: 6445028
Filing Date: 2002-09-03
Classification: H01L

Abstract:
A semiconductor device comprising:a semiconductor substrate having a principal surface; first and second transistors formed on the principal surface of the semiconductor substrate; an insulating film formed over the principal surface of the semiconductor substrate so as to cover the first and second transistors; a first storage node having a first enclosed wall structure and being connected to the first transistor, wherein the first enclosed wall structure is formed over the insulating film and encloses a surface region of the insulating film; a second storage node having second enclosed wall structure and being connected to the second transistor, wherein the second enclosed wall structure is formed over the insulating film and surrounds the first enclosed wall structure; a capacitor insulating film covering the first and second enclosed wall structures; and a cell-plate formed over the capacitor insulating film; wherein a thickness of the first enclosed wall structure in a direction parallel to the principal surface of the semiconductor substrate is greater than a thickness of the second enclosed wall structure in the direction parallel to the principal surface of the semiconductor substrate.