目的 针对超薄蓝宝石晶片的双平面加工，研究基盘表面高度差对工件平面度的影响，确定双平面加工超薄蓝宝石晶片的有效性。方法 通过多种方式得到具有不同表面高度差(高度差分别为5.3、9.8、19.9、29.7 μm)的基盘，利用层叠式夹持方法对超薄蓝宝石晶片进行夹持(厚度0.17 mm)并进行双平面加工，获得不同高度差下的工件平面度。分别采用层叠式夹持方法及石蜡粘接的方法对超薄蓝宝石晶片进行双平面加工，通过对比实验验证层叠式夹持方法的有效性。结果 在4种不同表面高度差下加工的超薄蓝宝石晶片，其平面度随着高度差的增大而增大，但其增大的趋势远小于基盘平面度变化的趋势。层叠式夹持方式及石蜡粘接方式均可实现超薄蓝宝石的双平面加工，两者相差较小，层叠式夹持方式最终可获得表面粗糙度Ra=1.4 nm、平面度PV=0.968 μm的光滑表面。结论 基盘表面高度差应不低于超薄蓝宝石晶片的目标平面度，层叠式夹持方式在加工效果上与石蜡粘接方式相当，但单位时间内的加工效率高于石蜡粘接方式，具有较好的工程应用前景。

The purpose is to study the influence of the height difference of the substrate surface on the flatness of the workpiece and determine the double-sides processing effectiveness of ultra-thin sapphire wafers. Obtain the different height differences of baseplates with different surfaces (height difference of 5.3 μm, 9.8 μm, 19.9 μm, 29.7 μm) through various methods. By using the layer stacked clamping to clamp the ultra-thin sapphire wafer (thickness 0.17 mm) and perform double-sides processing, thus obtaining the flatness of the workpiece under different height differences. The two-layer processing of ultra-thin sapphire wafers is carried out by using the layer stacked clamping method and paraffin bonding method respectively, and the effectiveness of the layer stacked clamping method is verified through comparative experiments. The result shows that the flatness of ultra-thin sapphire wafers increases with the increase of height difference under four different surface height differences, but the increasing trend is far less than the base plate flatness change trend. Layer stacked clamping method and the paraffin bonding method can realize the double-plane processing of ultra-thin sapphire, and the difference between them is small. The layer stacked clamping method can finally obtain a smooth surface with surface roughness Ra=1.4 nm and flatness PV=0.968 μm. Through experimental analysis and verification, it is proved that the height difference of the baseplate surface should smaller than the target flatness of the ultra-thin sapphire wafer. The layer stacked clamping method is equivalent to the paraffin bonding method in processing effect, but the processing efficiency per unit time is higher than the paraffin bonding method, which has a good engineering application prospect.