Novel small contact fabrication technologies were proposed to realize reliable high density 256Mb PRAM(Phase Change Memory) product. Introducing the 2-step CMP (Chemical Mechanical Polishing) process and the ring-shaped contact structure, the contact area distribution was greatly improved even at the smallest contact diameter of 50nm node. The validity of this approach was directly confirmed by the evaluation of the functionality for the fabricated 256Mbit PRAM based on 0. 10μm CMOS technology.