Changes in the structure properties and CMP manufacturability of a poly-Si film induced by deposition and annealing processes

Abstract

A successful development of high-performance multilevel microdevices is attributed to the outstanding physical properties of a polycrystalline silicon (poly-Si) film which can be tailored by its process conditions. Here, we select deposition temperature and post-deposition annealing treatment as critical process parameters, followed by investigating their effects on both structure properties and chemical-mechanical planarization (CMP) manufacturability of a poly-Si film. Experimental samples are prepared through low-pressure chemical vapor deposition (LPCVD) poly-Si deposition at different temperatures of 545–625°C and thermal annealing treatment at 1050°C under nitrogen atmosphere. At first, the poly-Si sample is inspected to characterize changes in macroscopic structure properties caused by the critical process parameters, together with changes in its surface morphology and grain boundary density. Next, the sample is polished to quantify changes in poly-Si CMP manufacturability such as material removal rate (MRR) and surface roughness. A relation between changes in microscopic features and changes in macroscopic properties is also discussed in depth. A poly-Si film deposited at 625°C and then thermally annealed at 1050°C shows significant improvement in both structure and CMP manufacturing aspects. The findings of this paper can potentially have a significant impact on developing poly-Si-based multilevel microdevices.