Decreasing curing temperature of spin-on dielectrics by using additives

Abstract

Spin-on dielectric (SOD) is widely used in semiconductor industry, to form insulating layers including shallow trench isolation (STI) or inter-layer dielectrics (ILD). SOD has several advantages over high density plasma chemical vapor deposition (HDP-CVD) for manufacturing process, such as less defect and higher throughput. However, both SOD and HDP-CVD have a drawback, which is a high temperature curing process required to make pure silicon oxide layers. High temperature curing could cause high stress and thermal distortion. These disadvantages are becoming more problematic as the semiconductor device shrinks. To resolve the problem, we tested several additives to moderate the curing temperature. It was found out that amine compounds were effective to convert SOD polymer into silicon oxide, therefore the curing process could be performed at a lower temperature. We also observed that the SOD films containing amine additives have higher etch resistance during a wet etch process. These results, as well as the lower curing temperature, are beneficial for manufacturing insulating layers. Further investigation is ongoing to characterize other film properties of the SOD with additives, and to optimize the formulation conditions according to the requirements of manufacturing processes.