SiC晶片双面和单面抛光相结合的化学机械抛光

Chemical Mechanical Polishing Combined Double-Side Polishing with Single-Side Polishing for the SiC Wafer

以碳化硅(SiC)晶片为加工对象,提出了双面化学机械抛光和单面化学机械抛光相结合的抛光方法。先在双面抛光机上对SiC晶片硅面和碳面同时进行化学机械抛光,然后采用单面抛光机对硅面进行化学机械抛光。研究了此方法加工碳化硅晶片的特点,对比分析了采用此方法与传统单面抛光加工晶片的几何参数。采用表面缺陷测试仪和原子力显微镜检测加工晶片的表面形貌。结果表明,双面抛光5 h后,碳面无划痕,表面粗糙度达到0.151 nm,硅面则存在较多浅划痕,表面出现了一些类似台阶的结构;采用单面抛光工艺对硅面抛光1 h后即可获得具有规则排列原子台阶构型、无划痕的表面;与传统的单面抛光工艺相比,此方法加工晶片的几何参数优异,其中总厚度变化(TTV)值小于1.5μm,局部厚度变化(LTV)值小于0.6μm,翘曲度一致性好。

A polishing method combined with double-side chemical mechanical polishing and single-side chemical mechanical polishing was proposed for the silicon carbide(SiC)wafer.Firstly,the Si face and C face of the SiC wafer were chemically mechanically polished simultaneously with a double-side polishing machine,and then the Si face was chemically mechanically polished with a single-side polishing machine.The characteristics of the polished SiC wafer were studied by this method.The geometry parameters of the wafers processed by the method and the conventional single-side polishing method were compared and analyzed.The surface morphologies of the wafers were observed by surface defect inspection system and atomic force microscope.The results show that after double-side polishing for 5 h,C face has no scratch,the surface roughness is0.151 nm,and Si face has many shallow scratches,there are some like step-terrace structures on the surface.A scratch-free surface with an inerratic atomic step-terrace structure can be obtained after single-side polishing of Si face for 1 h.The geometry parameters of the polished SiC wafers by the method are excellent,compared with those of the polished SiC wafers by the conventional single polishing method.The total thickness variation(TTV)value is less than 1.5μm,the local thickness variation(LTV)value is less than 0.6μm,and the warpage has good consistency.