纳米聚集氧化硅固定磨料抛光布的抛光特性

针对传统磨料的固定磨料抛光布容易在加工表面产生划伤,以及材料去除效率低等问题,提出了采用微米级球形聚集氧化硅粒子的固定磨料抛光布。将纳米聚集氧化硅粒子添加到抛光布中,用pH为10.5的碱性水溶液替代传统的抛光液,进行了Si基板的的抛光加工试验。与传统采用不规则形状天然氧化硅及球形熔融氧化硅固定磨料抛光布进行了比较,得到了纳米聚集氧化硅的固定磨料抛光布的加工特性,并讨论了它的基本参数对加工特性的影响。实验得到了与现行纳米抛光液(重量百分比为3%,pH=10.5)相同的材料去除率,加工表面粗糙度降低了约30%。与传统不规则形状天然氧化硅磨料抛光布相比,纳米聚集氧化硅抛光布的磨料为球形,弹性系数仅为其1.4%~60%,因此不易划伤抛光表面。与熔融氧化硅抛光布相比,纳米聚集氧化硅抛光布在pH为10.5的碱性水溶液中磨料表面可吸附的-OH]离子提高了25倍,使得液相化学去除作用增大至去除率的70%以上。另外,随着纳米聚集氧化硅的微米粒径的增大,固定磨料抛光布的纳米级加工表面粗糙度几乎不变,但对前加工面表面粗糙度的去除能力明显增大,表现出微米粒径效应。

Polishing characteristics of fixed-abrasive pad by using nano-aggregate silica

A kind of fixed-abrasive pad by using nano-aggregate silica was proposed to overcome the shortcomings of the pads using conventional silica abrasives on its surface scratch and low removal efficiency. The nano-aggregate silica particles were added into the fixed-silica pad,and the polishing experiments of Si wafer were performed using this pad with D.I.water of pH=10.5 instead of conventional nanosilica polishing slurry. Several investigations were performed by comparing with fixed-silica pads using conventional irregular natural silica abrasive and spherical fused silica, the polishing performance the fixed-abrasive pad using nano-aggregate silica were obtained and some factors affecting the pad's polishing performance also were investigated. The material removal rate same as the exiting polishing nanosilica slurry (concentration 3wt%,pH=10.5) was obtained, and polished surface roughness was decreased by about 1/3. Compared with the pad with fixed-conventional natural silica, the proposed fixed-aggregate silica pad is not easy to scratch Si wafer, because the nano-aggregate silica is not only a spherical shape but also has a elastic coefficient down to its 1.4%-60%. As compared with the pad with spherical fused silica, the proposed fixed-aggregate silica pad improves its adsorb-OH] ion by 25 times in D.I.water of pH=10.5, and allows the removal of material mainly came from chemical removing to be more than 70%. Moreover, nanoscale polished surface roughness is almost no changed with increasing the sizes of fixed-aggregate silica particles, but the polishing ability of pre-polishing surface roughness has been increased, which shows a micron particle size effect.