Patent ID: 8212233

Claim:
An integrated circuit structure comprising: a dielectric layer comprising an upper portion and a lower portion, wherein the dielectric layer is selected from the group consisting essentially of an inter-layer dielectric (ILD) and an inter-metal dielectric (IMD); a phase change random access memory (PCRAM) cell comprising a phase change strip, wherein the phase change strip is on the lower portion of the dielectric layer and comprises a top surface lower than a top surface of the dielectric layer, and a bottom surface higher than a bottom surface of the dielectric layer; a first conductive column electrically connected to the phase change strip, wherein the first conductive column extends from the top surface of the dielectric layer down into the dielectric layer; and a second conductive column in a peripheral region, wherein the second conductive column extends from the top surface of the dielectric layer down into the dielectric layer, and wherein the first conductive column and the second conductive column have different heights.