VLSI工艺中BPSG薄膜的研究

Research of BPSG Thin Films in VLSI Processing

BPSG(硼磷硅玻璃)薄膜作为一种重要的层间介质,在半导体集成电路中广泛使用。常压化学气相沉积的BPSG薄膜中B、P含量(质量分数)对BPSG的性能有着显著影响。以WJ—999R机台为基础,详细研究了B、P含量的变化对对BPSG薄膜的沉积率、蚀刻率及其对回流效果的影响。研究发现:沉积率随着B含量的增加而增加;当P含量由0至1%时沉积率突然降低,随后随P含量的增加无显著变化。蚀刻率则随B含量的增加而降低,随P含量的增加而增加。B含量对回流效果的影响显著强于P含量的影响,每增加1%的B,玻璃软化温度降低约40℃。过高过低的B、P含量会产生异常,在3%B,5%P含量下BPSG薄膜有着优良的性能。

As an important inter-layer dielectric, BPSG thin films deposited by atmospheric pressure chemical vapor deposition (APCVD) were used widely in most wafer techniques. The properties (including deposit rate, etching rate and reflow effects) of BPSG thin films with different B、P weight percentage concentration were studied based on the machine of WJ—999R. Obtained results indicate that deposit rate increases with the increasing of B concentration, rapidly decreases with the increasing of P concentration from 0 to 1wt% and subsequently doesn’t change obviously with the increasing of P concentration. Etching rate decreases with the increasing of B concentration and just the contrary to P. B concentration has a greater impact on reflow effects than P, it has been reported that an increase in B concentration of 1 wt% decreases the reflow temperature by 40℃. Too higher or lower B、P concentration can cause some abnormal phenomena, and the optimum deposition conditions are presented: 3wt%B-5wt%P.