To provide a method for manufacturing a semiconductor device capable of reducing variations in heights of conductive films by accurately controlling etching by detecting a step portion composed of a bottom surface of a first groove portion and a side surface of a second groove portion when etching back a first conductive film and leaving the first conductive film in a part of the second groove.
A method for manufacturing a semiconductor device includes the steps of: forming a first groove portion 51 having a first width W1; forming a groove 15 having the first groove portion 51, a second groove portion 52 having a second width W2 narrower than the first width W1, and a step portion 54 by forming the second groove portion 52; forming an insulating film 16 covering an inner surface of the groove 15; depositing a first conductive film 56 in which the first and second groove portions are embedded in the groove in which the insulating film 16 is formed; and leaving the first conductive film 56 in a part of the second groove portion 52 by etching back the first conductive film 56.
Ishibashi Masayuki
Masaaki Ogata