6H-SiC晶片集群磁流变研磨工艺优化

Optimization of lapping technology based on cluster magnetorheological effect for 6H-SiC wafers

为了研究不同种类磨粒与羰基铁粉的粒径匹配性对加工效果的影响规律,并优化磁感应强度、研磨压力、研磨盘转速和工件转速等工艺参数,采用集群磁流变研磨方法对6H-SiC晶片进行了研磨试验。结果表明:当磨粒与羰基铁粉的粒径比约为1.5时加工效果较好;各工艺参数对6H-SiC加工的材料去除率的影响由大到小依次为磁感应强度、研磨盘转速、研磨压力、工件转速,对表面粗糙度的影响由大到小依次为磁感应强度、研磨压力、工件转速、研磨盘转速;磁感应强度可以改变羰基铁粉的吸附力,从而改变对磨粒的把持程度,成为影响加工效果最显著的因素。优化后的工艺参数组合为:工件转速60r·min-1;研磨盘逆向转速90r·min-1;研磨压力70kPa;磁感应强度0.012T。在此优化条件下能获得最大的材料去除率(0.498μm·min-1)和较低的表面粗糙度(86.3nm)。

To study the diameter matching influence principle of particle size of abrasives and carbonyl iron powder to process, and optimize the parameters including of magnetic field strength, lapping pressure, plate speed and workpiece speed, the experiments based on cluster magnetorheological effect for single〉crystal 6H-SiC wafers were conducted. The experimental results showed that, the best process effect could be obtained when the diameter ratio of abrasive to carbonyl iron powder is about 1.5. The im portant order from big to small of relevant factors that affect the lapping efficiency is magnetic field strength, plate speed, lapping pressure and workpiece speed. The order from big to small for surface roughness Ra value is magnetic field strength, lapping pressure, workpiece speed and plate speed. Due to the control to abrasives by carbonyl iron powder, magnetic field strength is the main factor of process effects. The optimized process parameters are workpiece speed of 60 r ~ min 1, plate reverse speed of 90 r ·min^-1, lapping pressure of 70 kPa, magnetic field strength of 0. 012 T. A maximum material removal rate of 0. 498 μ.m · min^-1 and a surface roughness Ra value of 86.3 nm can be obtained under the optimized condition.