200 mm重掺As硅片上APCVD法沉积SiO_(2)薄膜应力的研究  

Stress of SiO_(2) Films Deposited by APCVD on 200 mm Heavily As-Doped Silicon Wafers

作　　者：王海涛 张果虎 刘斌 王新 冯瑞琪 钟耕杭 Wang Haitao;Zhang Guohu;Liu Bin;Wang Xin;Feng Ruiqi;Zhong Genghang(National Engineering Research of Key Materials of Integrated Circuit,China GRINM Group Co.,Ltd.,Bejing 100088,China;GRINM Semiconductor Materials Co.Ltd.,Bejing 100088,China)

机构地区：[1]中国有研科技集团有限公司,集成电路关健材料国家工程研究中心,北京100088 [2]有研半导体硅材料股份公司,北京100088

出　　处：《稀有金属》2023年第6期834-842,共9页Chinese Journal of Rare Metals

基　　金：国家重点研发计划项目(2017YFB0305603)资助。

摘　　要：常压化学气相沉积(APCVD)方法生长的SiO_(2)薄膜沉积在硅抛光片背面用于防止自掺杂效应,也在一些电子器件制造中用于绝缘层材料,它具有无定型晶体的结构,薄膜中的孔隙结构和表面结构对薄膜的应力产生影响。本研究中对APCVD沉积的二氧化硅薄膜在不同工艺条件下产生薄膜应力、热处理后薄膜应力变化以及在存放过程中的应力变化进行了测试。实验结果表明:SiO_(2)薄膜的沉积工艺不同,薄膜结构也会有差异,其中工艺温度影响尤其显著;经过热处理后的SiO_(2)薄膜结构发生变化,主要体现在孔隙内-OH的脱离,Si=O键、Si-Si键减少和消失,1100℃以上的热处理可以导致薄膜向晶体型转变,薄膜应力会随着结构改变而发生变化;薄膜在特定条件下存放一段时间后,表面和空隙内的-OH会吸附周围环境中的H2O,孔隙填充使薄膜应力发生自然释放现象;经过热处理后的SiO_(2)薄膜应力自然释放明显减弱,这与SiO_(2)薄膜经过热处理后的结构发生变化有关。SiO_(2) film deposited by APCVD on the back-surface of the polished wafer was used to prevent self-doping,and also used as insulating material in some electronic device manufacturing.The structure of this film was amorphous crystal.The pore and surface structure in film would affect the stress of film.In this study,the stress of the silicon dioxide film deposited by APCVD under different process conditions,the change of film stress after heat treatment,and the change of film stress with different storage time were tested.In the experiment,scanning electron microscope(SEM)and transmission electron microscope(TEM)were used to observe the surface and internal structure of the film.The initial stress of SiO_(2) film grown on 200 mm silicon substrate by APCVD was compressive stress.This stress came from the structure of SiO_(2) film.The film structure was very loose due to the rapid deposition of APCVD and the lack of grain formation process.During the film deposition,some gas would be sealed in the pores of the film,and the pore shrinkage would be happened after the cooling of the film deposition,so that the film formed compressive stress on the surface of wafer.In this study,the wafer thickness was 745μm,the initial bow value of SiO_(2) film with a thickness of 600 nm was 25μm,and the stress was about 120 MPa.The film stress increased with the increase of the thickness.When the film thickness reached 3.8μm,the film cracking was caused by excessive stress and substrate deformation,and the film stress decreased instantaneously.The stress performance of SiO_(2) films with the same thickness deposited on silicon substrates with different thickness was different.In this study,it was found that the thickness of deposited films was 600 nm and the thickness of substrates was≤620μm,the membrane stress calculated was about 278 MPa,while the thickness was≥745μm and the stress was about 141 MPa.The change was no longer obvious with the increase of thickness.The reason was that the service conditions of deformation meth

关 键 词：二氧化硅薄膜 无定型结构 薄膜应力 热处理 

分 类 号：TN304[电子电信—物理电子学]