Random access memory device and manufacturing method for nodes thereof

A manufacturing method for a plurality of nodes of a random access memory (RAM) device, comprising:

• forming a shallow trench isolation (STI) layer on a substrate to divide the substrate into a plurality of active areas, wherein the adjacent portions of any two adjacent active areas and the portion of the STI layer arranged therebetween are defined as a unit region;
• sequentially forming a first insulating layer and a hard mask layer on the substrate, wherein the hard mask layer has a specific pattern;
• etching the first insulating layer of each unit region to form a first hole for exposing the STI layer of each unit region and partial of the active areas of each unit region;
• filling a conductive material in the first hole of each unit region to form a conductor;
• forming a protective layer on the top surface of the conductor of each unit region, wherein each protective layer has an opening aligning the STI layer of each unit region;
• etching the conductor of each unit region from the opening until the STI layer to form a second hole for exposing the STI layer of each unit region, wherein the aperture of the second hole is smaller than the aperture of the first hole, each conductor is divided into two nodes by the second hole arranged therebetween, and each node is used for electrically connecting to a capacitor;
• and
• forming a second insulating layer in the second hole of each unit region for electrically isolating the nodes of each unit region.