磁性复合流体对砷化镓晶片的超精密表面抛光

Ultra-precision Surface Polishing of Gallium Arsenide Wafer Using Magnetic Compound Fluid Slurry

摘要:

研究了磁性复合流体（MCF）浆料对砷化镓（GaAs）晶片表面纳米精密抛光的影响。通过混合CS羰基铁颗粒（CIPs）、Al₂O₃磨料颗粒、α-纤维素和磁性流体制备MCF浆料。首先，通过设计用于产生旋转磁场的MCF单元，建立了抛光装置。然后，对GaAs晶片表面进行了点抛光实验，以阐明MCF成分对不同抛光位置的表面粗糙度R_a和材料去除（MR）的影响。最后，使用含有不同直径颗粒的水基MCF浆料进行了扫描抛光实验。结果表明，在点抛光的情况下，水基和油基MCF处理后的初始表面粗糙度从954.07 nm分别降至1.02和20.06 nm。此外，MR的深度随着抛光时间的增加而线性增加。使用水基MCF的MR深度是使用油基MCF抛光的2.5倍。同时，抛光区的横截面轮廓显示出W型，这表明点抛光工件表面的MR不均匀。通过扫描抛光，抛光区的横截面轮廓显示出U型，这表明在给定的实验条件下，无论使用何种MCF，MR都是均匀的。使用含有直径为0.3 μm的磨粒的MCF能够获得R_a为0.82 nm的最光滑工作表面，同时MR速率为13.5 μm/h。

Abstract:

The effect of magnetic compound fluid (MCF) slurry on the gallium arsenide (GaAs) wafer surface after nano-precision polishing was investigated. MCF slurry was prepared by mixing CS carbonyl iron particles (CIPs), Al₂O₃ abrasive particles, α-cellulose, and magnetic fluid. Firstly, a polishing device was assembled by designing MCF unit for the generation of revolving magnetic field. Then, the spot polishing experiments were performed on GaAs wafer surface to clarify the effects of MCF components on the surface roughness R_a and material removal (MR) at different polishing positions. Finally, the scanning polishing experiments were conducted using water-based MCF slurry containing particles with different diameters. Results show that after spot polishing with water-based and oil-based MCFs, the initial surface roughness R_a of 954.07 nm decreases to 1.02 and 20.06 nm, respectively. Additionally, the depth of MR is increased linearly with prolonging the polishing time. It is worth noting that the MR depth of surface after polishing with water-based MCF is 2.5 times higher than that with oil-based MCF. Meanwhile, the cross-section profile of the polished zone shows the W shape, which indicates the non-uniform MR on the workpiece surface after spot polishing. After scanning polishing, the cross-section profile of the polished zone shows the U shape, which indicates that MR is uniform under specific experiment conditions, regardless of the MCF types. The smoothest work surface with R_a=0.82 nm is achieved using MCF with abrasive particles of 0.3 μm in diameter, and MR rate is 13.5 μm/h.