Optimization of nitride films for linear pre-metal dielectric process

With applications in current semiconductor manufacturing, the characteristics of nitride films were investigated for the optimization of pre-metal dielectric (PMD) linear nitride process. For the purpose of this study, the deposit condition of nitride films was divided into four areas such as protected overcoat (PO) nitride process, baseline process, low hydrogen process, and low hydrogen process with high stress, respectively. The correlation between boro-phospho-silicate-glass (BPSG) depositions and their densification was also examined and Fourier transform infrared spectroscopy (FTIR) area method was used to analyze the change of Si-H and Si-NH-Si bonding density. In addition, the generation of cracks on the wafer edge was evaluated after BPSG densification. The stress changes of nitride film as a function of radio frequency (RF) power variation were used to determine the quality of the deposited films. Resultantly, the low hydrogen process was recommended as an optimized condition for linear PMD nitride film.