Fusion, Quality-Based.

In a DRAM adopting a self-aligned contact structure, an opening portion of predetermined size is formed in advance in an insulation film which surrounds an on-field gate electrode formed on an element isolating insulation film. The on-field gate electrode contacts a gate contact through the opening portion. A contact hole for the gate contact can thus be formed in self-alignment as can be the contact holes for a bit-line contact and an active contact. Consequently, the contact hole for the gate contact reaching the on-field gate can be formed simultaneously with the contact holes for the bit-line contact and active contact, thereby greatly reducing the number of manufacturing steps.