SiC晶片研磨加工亚表面损伤深度的研究

Study on the Subsurface Damage Depth of the Lapped SiC Wafers

SiC晶片研磨加工表面层损伤深度直接影响后续抛光加工的成本和效率,但SiC单晶是典型的难加工材料,亚表面损伤检测极为困难。文中利用截面显微检测技术对SiC晶片研磨加工亚表面损伤深度进行了检测分析,并研究了研磨方式、工艺参数对损伤深度的影响及晶片上损伤深度的分布规律。结果表明,同样的研磨工艺参数条件下,固结磨料研磨SiC晶片损伤深度略小于游离磨料研磨晶片的损伤深度。固结磨料研磨时,随着磨料粒度从W7增大到W28,损伤深度由3.0μm增大到4.7μm。随着研磨压力从1 psi增大到3 psi,晶片损伤深度从4.1μm增大到4.9μm。在整个晶片上,损伤深度由中心向边缘沿径向逐渐增大,增大幅度约为0.6~1.0μm。

The subsurface damage depth（SSD） of the lapped SiC wafers directly affects the cost and efficiency of the following polishing process.But because the SiC single crystal is the typical difficult to machine material,the subsurface damage measurement of the SiC wafers are very difficult.The SSD of the lapped SiC wafers are measured by the cross-sectional microscopy detection in this paper.The effect of lapping mode、process parameter on the SSD and the SSD distribution are researched.The results show that the SSD of fixed abrasive lapped SiC wafer is smaller than that of free abrasive lapped SiC wafer under the same lapping parameter.When SiC wafer lapped by fixed abrasives,with the abrasive grit size increases from W7 to W28,the SSD increases from 3.0 μm to 4.7 μm.With the lapping pressure increases from 1 psi to 3 psi,the SSD increase from 4.1 μm to 4.9 μm.The SSD distribution increases from circle to edge along the radial direction and the increased value is about 0.6 μm to 1.0 μm.