Semiconductor nonvolatile memory device with inter-gate insulating film formed on the side surface of a memory cell and method for manufacturing the same

Abstract

A nonvolatile semiconductor device and method having a plurality of series-connected memory cells with floating and control gate electrodes, and a first insulating layer formed between the gate electrodes. One of the memory cells has the floating gate formed to contact the control gate electrode through an aperture in the insulating layer. The insulating layer is removed to form spaces between the gate electrodes. A second insulating film is formed in the spaces between the gate electrodes. The dummy electrode supports the series of gate electrodes to maintain the spaces between the electrodes. The second insulating layer is formed to be continuous in the spaces and on side surfaces of the gate electrodes. The second insulating layer may have a stacked structure with n layers in the spaces and (n−1)/2 layers on the side surfaces.