Method of fabricating semiconductor device and the semiconductor device

A method of fabricating a semiconductor device, comprising:

• forming an insulating film and a core-forming film above a semiconductor substrate in turn;
• processing the core-forming film into a plurality of core patterns;
• forming a mask-forming film with a predetermined film thickness along upper surfaces and side surfaces of the core patterns and portions of an upper surface of the insulating film exposed between the adjacent core patterns;
• forming a plurality of mask patterns by anisotropically etching the mask-forming film until the upper surfaces of the core patterns are exposed;
• removing the core patterns with respective upper surfaces being exposed;
• forming a plurality of wiring groove patterns by etching the insulating film with the mask patterns serving as masks after the core pattern has been removed;
• and
• forming a plurality of buried wirings by burying an electrically conductive film in the wiring groove patterns, wherein in forming the mask patterns,
• a facing pair includes a pair of the mask patterns facing the core pattern located between the paired mask patterns, the mask patterns of the facing pair having respective lower portions spaced from each other by a first distance;
• an adjacent pair includes a pair of the mask patterns adjacent to each other with a space having no core pattern, the mask patterns of the adjacent pair having respective lower portions spaced from each other by a second distance;
• and
• the mask patterns are formed so that the second distance is larger than the first distance.