面向水平GAA内侧墙模块的干法Si_(0.7)Ge_(0.3)选择性刻蚀研究  

Dry Selective Etching of Si_(0.7)Ge_(0.3) for Horizontal GAA Inner Spacer Module

作　　者：刘阳 李俊杰[2,3] 吴次南 张青竹 王桂磊[4] 周娜 高建峰 孔真真 韩江浩[2] 罗彦娜 刘恩序 杨涛 李俊峰 殷华湘 罗军[2,3] 王文武 LIU Yang;LI Junjie;WU Cinan;ZHANG Qingzhu;WANG Guilei;ZHOU Na;GAO Jianfeng;KONG Zhenzhen;HAN Jianghao;LUO Yanna;LIU Enxu;YANG Tao;LI Junfeng;YIN Huaxiang;LUO Jun;WANG Wenwu(College of Big Data and Information Engineering,Guizhou University,Guiyang 550025,China;Institute of Microelectronic of the Chinese Academy of Sciences,Beijing 100029,China;School of Integrated Circuits,University of Chinese Academy of Sciences,Beijing 100049,China;Beijing Superstring Academy of Memory Technology,Beijing 100176,China)

机构地区：[1]贵州大学大数据与信息工程学院,贵阳550025 [2]中国科学院微电子研究所,北京100029 [3]中国科学院大学集成电路学院,北京100049 [4]北京超弦存储器研究院,北京100176

出　　处：《真空科学与技术学报》2023年第5期396-402,共7页Chinese Journal of Vacuum Science and Technology

基　　金：中科院先导A项目(XDA0330300);中国科学院支撑技术人才项目(E2YR01X001);环栅(GAA)纳米片器件干法释放功能开发(E2SH01X)。

摘　　要：针对环栅(Gate-All-Around,GAA)Si_(0.7)Ge_(0.3)的内侧墙(Inner spacer)空腔刻蚀难以精确控制尺寸和形貌的问题,本研究基于常规电感耦合等离子体(inductively coupled plasma,ICP)刻蚀设备,采用CF_(4)/O_(2)/He混合气体进行Si_(0.7)Ge_(0.3)干法各向同性选择性刻蚀实验,探究了包括激励射频源(source radio frequency,SRF)功率、气压、刻蚀前侧壁清洗工艺等因素对刻蚀结果的影响与机制。研究结果表明,SRF对刻蚀深度的影响是存在线性区与准饱和区的,气压与刻蚀深度在实验区间内呈二次函数关系,稀释的氢氟酸(Diluted HF,DHF)与O_(3)交替清洗相对单一的DHF清洗方案在界面钝化层的去除与刻蚀形貌的控制上有更优的表现。经工艺方案优化,最终获得良好的工艺结果:刻蚀精度达到了0.61 nm/s,最优粗糙度Rq为0.101 nm,刻蚀轮廓矩形度高(d/t~83.3%)。本研究为内侧墙空腔刻蚀提供了一种解决方案。Aiming at the issue that it is difficult to accurately control the size and profile of the inner spacer cavity etching of Si_(0.7)Ge_(0.3) in Gate-All-Around(GAA)process flow,based on the conventional inductively coupled plasma(ICP)etching tool,dry isotropic selective etching experiment of Si_(0.7)Ge_(0.3) was carried out with CF_(4)/O_(2)/He mixed gas.The effects and mechanisms of factors such as the power of SRF(source radio frequency),gas pressure,and the sidewall cleaning process before etching were explored.The results show that there are linear and quasisaturated regions in the effect of SRF on the etching rate,and there is a quadratic function relationship between gas pressure and etching rate in the experimental range.Diluted HF(DHF)and O3 alternate cycle cleaning process has a better performance than the single DHF cleaning in the removal of the interface passivation layer and the control of the etching profile.After the optimization of the process scheme,better process results are obtained:the etching accuracy reaches 0.61 nm/s,the optimal roughness Rq is 0.101 nm,and the rectangle of the etching profile is high(d/t~83.3%).This study provides a solution for the inner spacer cavity etching.

关 键 词：Si_(0.7)Ge_(0.3) 空腔刻蚀 刻蚀精度 粗糙度 刻蚀形貌 

分 类 号：TN405.98[电子电信—微电子学与固体电子学]