Borophosphosilicate glass (BPSG) film with a high boron and phosphorus concentration that exceeds a certain limit shows the growth of crystalline particles on the surface after annealing above 900 degrees C in a nitrogen atmosphere. We studied the crystalline particle growth mechanism on BPSG, and found that the particles are BPO4 crystal that grows during the cooling step at the end of annealing. Hence, rapid cooling of the BPSG after annealing suppresses particle growth. We also found that particle growth is affected by the annealing atmosphere; being more suppressed in an oxygen atmosphere than in a nitrogen atmosphere. In an oxygen-steam atmosphere, particle growth is completely suppressed. From the measurements of boron and phosphorus out-diffusion in different annealing atmospheres, we concluded that particle growth is caused by the gas-phase reaction of the out-diffused phosphorus and boron from the BPSG film.