Generation and resolution of dense defect in boron-doped oxide film

Higher in-film defect count on BSG layer results in micro masking at AA pattern in deep trench DRAM process were found to cause serious yield loss. Consequently, root cause and prevention of dense defect generation are well discussed in this paper. The source and type of dense defect were analyzed via SEM/EDS, nevertheless, no any foreign particle evidence via the inspection on SEM cross-section images. The poor thermal conduction caused lower wafer temperature and introduced un-decomposed of TEB and TEOS on wafer surface. The un-decomposed TEOS or TEB would be a nucleation site to form a dense defect. The experiments of various heater temperatures also support the suspecting. Additionally, the phenomenon and mechanism of the TEB flow and deposition rate change before dense defect occurrence are presented and discussed in this work.