Investigation on the Correlationship between Process Performances and Composition of CMP Slurry Designed for GST Alloy Polishing

Newly developed technology utilizes phase change materials in integrated circuit to produce a new type of memory device, namely PRAM. The delicate design of such device poses new challenges for CMP (Chemical Mechanical Polishing), which is one important process to construct memory cells in PRAM. In this paper, recent efforts in developing slurries for GST CMP are described. The preliminary investigation focuses on some of the most concerned issues in GST CMP, such as GST removal rate and removal rate selectivity, post-CMP surface roughness, galvanic effect between different materials and composition consistency of GST alloy. Performance of the testing slurries is analyzed on a laboratory level using physical analytical instruments, such as SEM, EDX, AFM, as well as electrochemical analytical tools