多晶硅沉积厚度对氧沉淀和洁净区形成的影响  

Formation of Oxygen Precipitation and Denuded Zone Influenced by Polysilicon Deposition Thickness

作　　者：黄栋栋[1] 曲翔[1] 刘大力[1] 周旗钢[1] 刘斌[1] 刘红艳[1] 

机构地区：[1]北京有色金属研究总院有研半导体材料有限公司,北京100088

出　　处：《稀有金属》2016年第12期1256-1259,共4页Chinese Journal of Rare Metals

基　　金：国家重大科技专项项目(2010ZX02302-001)资助

摘　　要：硅片背面沉积多晶硅是半导体生产中常用的吸杂手段,多晶硅中存在着大量的晶界,可以吸除金属杂质,它还可以影响硅片内氧沉淀的分布,增强内吸杂的作用。通过控制低压化学气相沉积(LPCVD)系统的沉积时间,在硅片背面沉积不同厚度的多晶硅薄膜,借助择优腐蚀和金相显微(OM)观察等手段研究了沉积厚度对重掺硼硅片内氧沉淀形成与分布的影响。结果表明:沉积的多晶硅薄膜越厚,硅片的形变量越大,小尺寸的氧沉淀数量增多并在表面附近聚集,大尺寸的氧沉淀则倾向于在体内和背面形成,洁净区的厚度则减小直至无洁净区建立。多晶硅薄膜通过对硅片施加应力引起硅片形变,从而影响氧沉淀硅片体内形成的位置,起到促进内吸杂的作用。最佳多晶硅沉积厚度为800 nm。Polysilicon gettering has been widely used in semiconductor production. Metal impurities can be gettered for the presence of grain boundaries in polysilicon. Meanwhile, polysilicon can promote the internal gettering by affecting the formation of oxygen pre-cipitation. By controlling the deposition time of low pressure chemical vapor deposition （LPCVD） system, polysilicon thin films with different thicknesses were obtained. The effect of deposit thickness on the distribution of oxygen precipitation in heavily boron-doped silicon was investigated by preferential etching combined with optical microscopy （OM）. The results showed that the thicker the poly- silicon was, the larger the wafer deformation became; small oxygen precipitations near surface increased and large oxygen precipitations tended to appear near backside ; the thickness of denuded zone reduced until disappeared. Polysilicon thin film affected the distribution of oxygen precipitations in wafer by putting stress on it, therefore promoted the internal gettering. The optimal polysilicon deposition thickness was 800 nm.

关 键 词：重掺硅片 多晶硅吸杂 择优腐蚀 氧沉淀 

分 类 号：TN304[电子电信—物理电子学]