CMP Process for Phase Change Materials

Since the CMP process depends on chemical and mechanical effects, the interaction with the physical and chemical properties of the GST alloy play very important roles during the CMP process. In this paper, the impact of the CMP process on a soft GST alloy will be discussed. In addition, the paper addresses how major chemical properties of the GST alloy affect the GST CMP process. For example, in order to remove the three different elements of GST material during the CMP process, it is critical to understand how the alloy's chemical behavior changes when interacting with the CMP slurries. A fully characterized GST CMP baseline process, including its process and defect results, will be presented. The methods used to optimize the CMP process and reduce post-CMP defects will also be discussed.