Method of manufacturing semiconductor device with word lines

A method of manufacturing a semiconductor device, comprising:

• providing a substrate comprising a first capacitor structure and a second capacitor structure therein;
• forming a metallization layer on the substrate;
• forming an upper dielectric layer over the metallization layer;
• forming a first sacrificial layer and a second sacrificial layer, each of which penetrates the upper dielectric layer and the metallization layer, wherein the first sacrificial layer vertically overlaps the first capacitor structure and the second sacrificial layer vertically overlaps the second capacitor structure;
• removing the upper dielectric layer;
• forming a width controlling structure between the first sacrificial layer and the second sacrificial layer, wherein the width controlling structure defines a recess exposing the metallization layer;
• forming a protective layer within the recess of the width controlling structure;
• removing the width controlling structure to expose a portion of the metallization layer;
• and
• patterning the metallization layer to form a word line between the first sacrificial layer and the second sacrificial layer.