Impact of Organic Contamination From Partially Fluorinated O-Ring in High-Temperature Nitride Process on DRAM Performance

This paper is concerned with organic contamination from a partially fluorinated o-ring used in a furnace for a high-temperature process. The organic outgas was confirmed by Fourier transform infrared analysis of the furnace exhaust gas. Experiments from practical trench dynamic random access memory disclosed that outgassed organic contaminants from the nitride process would severely worsen the tunneling leakage current performance of the storage dielectric and lead to fatal yield loss even though the cell capacitance was almost uninfluenced. To eliminate this yield detractor requires several test runs prior to real production after installation of the partially fluorinated o-ring; otherwise, a fully fluorinated o-ring is needed. From a cost viewpoint, the latter is highly suggested.