单晶硅片磨削的表面相变

Phase transformations of grinding monocrystalline silicon wafer surfaces

为揭示硅片自旋转磨削加工过程中材料的去除机理,采用显微拉曼光谱仪研究了硅片磨削表面的相变。结果表明:半精磨和精磨硅片表面存在α-Si相、Si-Ⅲ相、Si-Ⅳ相和Si-Ⅻ相,这表明磨削过程中Si-Ⅰ相发生了高压金属相变(Si-Ⅱ相),Si-Ⅱ相容易以塑性方式去除。粗磨硅片表面没有明显的多晶硅,只有少量的非晶硅出现,材料以脆性断裂方式去除。从粗磨到精磨,材料去除方式由脆性断裂去除向塑性去除过渡。粗磨向半精磨过渡时,相变强度越大,材料的塑性去除程度越大;半精磨向精磨过渡时,相变强度越小,材料的塑性去除程度越大。

In order to understand the material removal mechanism during wafer rotation grinding, the phase transformations on the ground silicon wafer surface were investigated by Raman microspectros- copy. The results existing the amorphous silicon （α-Si）, Si-Ⅲ phase, Si-Ⅳ phase and Si-Ⅻ phase on the semi-fine and fine ground wafer surfaces indicate that the Si-Ⅰ phase has been transformed into ductile metal phase （Si-Ⅱ phase） during grinding,and the Si-Ⅱ phase is ductile and easily be removed by ductile mode. There is no obvious polycrystalline silicon on the rough ground wafer surface, but very small amounts of a-Si is observed, these materials are removed by brittle mode. From rough grinding to fine grinding, the material removal mode changes from micro-fracture mode to ductile mode gradually. During the transition from rough grinding to semi-fine grinding, the ductile mode removal degree increases with the increasing phase transformation degree; the transition from semi-fine grinding to fine grinding, the ductile mode removal degree increases with the decreasing phase transformation degree.