In a contact structure having a large aspect ratio in a LSI device incorporating
DRAM cells and logics, for the purpose of preventing over-etching of a device isolation
insulating film and an impurity diffusion layer and thereby minimizing junction
leakage, a first etching stopper layer covering a peripheral MOS transistor and
a second etching stopper layer overlying a capacitor section of a DRAM memory cell
are formed. An impurity diffusion layer of the peripheral MOS transistor is connected
to a metal wiring layer formed in an upper level of the capacitor section by an
electrode layer extending through the first and second etching stopper layers.
At least one of such impurity diffusion layers is connected to the electrode layer
at its boundary with the device isolation insulating film, and depth of the bottom
of the electrode layer formed on the device isolation insulating film from the
surface of the impurity diffusion layer is shorter than the junction depth of the
impurity diffusion layer.
