Optimizing Stressor Film Deposition Sequence in Polish Rate Order for Best Planarization

摘要

Chemical Mechanical Polish (CMP) is one of the key technologies for the development of modern high performance integrated circuits. The requirements for the CMP uniformity get extremely demanding in order to meet the litho requirements for 32nm technology node and beyond. In this paper, two kinds of orders related to the stressor films that affect the CMP uniformity are revealed. The first is the stressor films deposition order according to the CMP polish rate of each stressor film. The second is the stress gradients order that formed inside the films sitting on top of the stressors. Through the optimization of the order, we show successfully removal of couple hundreds angstroms stressor step heights within 300mm wafer range. The method developed here can also find applications in microelectromechanical systems and 3D integration circuits.