Manufacturing method of semiconductor device

A manufacturing method of a semiconductor device comprising:

• forming, on a substrate, protruding portions comprising first films respectively provided on the surfaces thereof;
• forming a second film different from the first films so as to fill a depressed portion between the protruding portions and to cover the protruding portions;
• processing in such a manner that the top surface of the second film on the depressed portion is higher than the top surface of the second film on the protruding portions after forming the second film to cover the protruding portions;
• and
• polishing the second film on the depressed and protruding portions to expose the first films,
• wherein processing in such a manner that the top surface of the second film on the depressed portion is higher than the top surface of the second film on the protruding portions comprises:
• covering the second film on the depressed portion and the protruding portions with a third film,
• exposing the surface of the second film on the protruding portions after polishing the third film on the protruding portions,
• polishing and removing the exposed second film on the protruding portions,
• removing the third film covering the second film on the depressed portion after polishing and removing the exposed second film on the protruding portions, and
• after removing the third film covering the second film on the depressed portion, exposing the first film on the protruding portion.