材料期刊网

针对3英寸SiC衬底的精密抛光加工,设计了其无架行星式适应性双面抛光机构的几何模型.推导了抛光垫上任一点磨粒 A 相对 SiC 衬底的运动轨迹方程.利用C＃和Matlab 联合仿真对太阳轮、行星轮、齿圈以及抛光盘转速和运动轨迹的曲率等工艺参数进行了分析.基于 ADAMS 工具,进行了双面抛光的运动学仿真,得到了3英寸 SiC 衬底表面5点的位移、速度、加速度随时间变化的曲线.仿真结果表明,当齿圈和太阳轮转速比m＝－1．25；抛光盘和太阳轮转速比n＝1；磨粒分布半径(RA )适当增加时,磨粒在晶片上走过的轨迹范围增大；得到的抛光轨迹更加均匀.根据仿真的最优参数进行实验,机械抛光后获得了材料去除率(MRR)为1~2μm/h,表面粗糙度(Ra )小于2 nm,总厚度变化(TTV)、弯曲度(BOW)、翘曲度(Warp)均小于15μm 的 SiC 衬底.验证了理论模型的正确性和虚拟样机的合理性.

Oriented to the precision polishing of the 3inch SiC substrate,the geometric model of the double-sided polishing mechanism without planet carrier was designed.The traj ectory equation about any abrasive A on polis-hing pad relative to SiC substrate was derived.The process parameters such as the speed of the sun gear,planet gear ,ring gear and the polishing plate and the track curvature were analyzed by the co-simulation with C# and Matlab.Besides,based on the ADAMS,kinematics simulation of double-sided polishing was carried out.The curves of displacement,velocity and acceleration versus time of the 5 points on the surface of 3inch SiC sub-strate have been got.The simulation results show that the more uniform polishing track obtain when the abra-sive distribution radius (RA)appropriately increase,the range of traj ectory of abrasive on the wafer was in-creased,while the speed ratio m of the ring gear to the sun gear was -1.25 and the speed ratio n of the polis-hing plate to the sun gear was 1 .The experiment was conducted according to the optimal parameters of the sim-ulation.The silicon carbide SiC substrate comes out with a material removal rate(MRR)range of 1-2μm/h, while the surface roughness(Ra)was less than 2 nm,and the total thickness variation(TTV),the bending of wafer(BOW)and the warpage(Warp)are both less than 1 5μm after the mechanical polishing.It verifies the correctness of the theoretical model and the rationality of the virtual prototype.