Fill for shallow trench isolation CMP

Shallow trench isolation (STI) is the mainstream CMOS isolation technology. It uses chemical mechanical planarization (CMP) to remove excess of deposited oxide and attain a planar surface for successive process steps. Despite advances in STI CMP technology, pattern dependencies cause large post-CMP topography variation that can result in functional and parametric yield loss. Fill insertion is used to reduce pattern variation and consequently decrease post-CMP topography variation. Traditional fill insertion is rulebased and is used with reverse etchback to attain desired planarization quality. Due to extra costs associated with reverse etchback, “single-step” STI CMP in which fill insertion suffices is desirable. To alleviate the failures caused by imperfect CMP, we focus on two objectives for fill insertion: oxide density variation minimization and nitride density maximization. A linear programming based optimization is used to calculate oxide densities that minimize oxide de...

• Type: Conference
• Year: 2006
• Where: ICCAD
• Authors: Andrew B. Kahng, Puneet Sharma, Alexander Zelikovsky
• Keywords: Calculated Oxide Density, Density Variation Minimization, Hardware, ICCAD 2006, Oxide Density Variation