Method of fabricating semiconductor device

A method of fabricating a semiconductor device, the method comprising:

• forming a dummy gate pattern on a substrate;
• forming an interlayer dielectric film that covers the dummy gate pattern;
• forming a first gate forming trench in the interlayer dielectric film by selectively removing the dummy gate pattern, the first gate trench defining inner walls;
• forming a sacrificial layer pattern on a top surface of the substrate in the first gate trench while exposing a top portion of the first gate trench, the sacrificial layer pattern does not contact a portion of the inner walls of the first gate trench;
• forming a second gate trench by etching the portion of the inner wall of the first gate trench that does not contact the sacrificial layer pattern, the second gate trench (1) having a topmost width greater than a bottommost width and (2) defining an inner wall that includes (i) a portion not in contact with the sacrificial layer pattern and (ii) a portion in contact with the sacrificial layer pattern;
• removing the sacrificial layer pattern in the second gate trench;
• and
• forming a non-dummy gate pattern in the second gate trench.

A method of fabricating a semiconductor device, the method comprising:

• forming a dielectric layer above a substrate;
• forming a first gate trench in the dielectric layer, the first gate trench having sidewalls;
• forming a sacrificial pattern layer in the first gate trench, the sacrificial pattern layer having an upper surface that is below an upper surface of the dielectric layer;
• after forming the sacrificial pattern layer in the first gate trench, increasing a width of at least a portion of the first gate trench to form a second gate trench such that a width of at least a portion of second gate trench decreases from the upper surface of the dielectric layer;
• removing the sacrificial pattern layer;
• after removing the sacrificial pattern layer, forming a gate insulation layer in the second gate trench;
• and
• forming a first gate metal film in the second gate trench.