硅片背面减薄技术研究

Study on Wafer Backside Thinning Technique

硅片背面磨削减薄工艺中,机械磨削使硅片背面产生损伤,导致表面粗糙,且发生翘曲变形。分别采用粗磨、精磨、精磨后抛光和精磨后湿法腐蚀等四种不同背面减薄方法对15.24cm(6英寸)硅片进行了背面减薄,采用扫描电子显微镜对减薄后的硅片表面和截面形貌进行了表征,用原子力显微镜测试了硅片表面的粗糙度,用翘曲度测试仪测试了硅片的翘曲度。结果表明,经过粗磨与精磨后的硅片存在机械损伤,表面粗糙且翘曲度大,粗糙度分别为0.15和0.016μm,翘曲度分别为147和109μm;经过抛光和湿法腐蚀后的样品无表面损伤,粗糙度均小于0.01μm,硅片翘曲度低于60μm。

In the process of grinding and thinning on the back of silicon wafers,mechanical grinding will cause damages on the backside,resulting in surface roughness and warping deformation.In this paper,four kinds of different backside thinning methods,such as rough grinding,fine grinding,polishing and wet etching,were used to reduce the backside of the 15.24 cm wafers.The surface and cross section morphology of the silicon wafers were characterized by scanning electron microscope,and the roughness of the surface was measured by atomic force microscopy.The warp degree of the silicon wafer was tested by surface metrology.The results show that there is a certain degree of damage in the silicon wafer after rough grinding and fine grinding,and the roughness of the silicon wafer is 0.15 and 0.016μm,respectively,and the wafer warp is 147 and 109μm.After polishing and wet etching,the wafer has no surface damage,the roughness of the samples is less than 0.01μm,and the warp degree of the silicon wafer is less than 60μm.