Dynamic random access memory devices and methods for manufacturing the same

A method for manufacturing a dynamic random access memory device, comprising:

• forming a plurality of bit line structures over a substrate in an array region and in a dummy region outside the array region;
• forming an insulating material layer between the bit line structures;
• forming a cap layer in the dummy region and exposing the array region, wherein the bit line structures covered by the cap layer forms a plurality of dummy bit lines, the bit line structures exposed by the cap layer forms a plurality of bit lines, and the insulating material layer covered by the cap layer forms a dummy insulating structure;
• removing the insulating material layer exposed by the cap layer to form a plurality of node contact holes in the array region;
• and
• forming a plurality of node contact plugs in the node contact holes, each of the node contact plugs located on the substrate at one side of a corresponding one of the bit lines, wherein the dummy insulating structure is arranged along with the node contact plugs.