Analysis of LPCVD process conditions for the deposition of low stress silicon nitride. Part I: preliminary LPCVD experiments
Analysis of LPCVD process conditions for the deposition of low stress silicon nitride. Part I: preliminary LPCVD experiments
复制标题
DOI：
10.1016/s1369-8001(02)00058-6
复制
发表时间：
2002-02-01
影响因子：
4.1
通讯作者：
Olson, JM
中科院分区：
文献类型：
--
作者：
Olson, JM
研究了各种工艺条件，以优化低压化学气相沉积低应力氮化硅薄膜的沉积条件。在标准的多晶片批量系统中进行的实验产生了折射率范围为约2.04至2.82且残余应力范围为约700 MPa拉伸至约90 MPa压缩的膜。残余应力和折射率之间的关系进行了表征，并将结果与技术文献中的结果进行了比较。通过增加气体流量使折射率增加超过约2.3并不能明显地降低残余应力，但对厚度均匀性和沉积速率具有显著的不利影响。与其他研究人员报告的结果相反，在这项研究中，没有观察到均匀性随着DCS/NH3比的增加而增加。通过抑制沉积系统的气体入口区域处的沉积速率同时增加后部处的沉积速率来最小化厚度不均匀性的努力没有成功。虽然增加系统排气端的温度旨在改善厚度不均匀性，但没有实现显著的厚度和折射率均匀性。在系统的排气端处沉积速率的降低和折射率的相应增加指示从系统的入口到排气的气体种类的变化。实验结果表明，随着DCS分压的增加，薄膜的折射率降低，沉积速率降低。这表明重复性运行中观察到的不均匀性是由于沿负载长度沿着的氨消耗所致。(C)2002爱思唯尔科技有限公司版权所有。
A wide range of process conditions were investigated to optimize conditions for the deposition of low stress silicon nitride films by low-pressure chemical vapor deposition. Experiments carried out in a standard, multi-wafer batch system generated films with an index of refraction ranging from about 2.04 to 2.82 and residual stress ranging from about 700 MPa tensile to -90 MPa compressive. The relationship between residual stress and index of refraction was characterized and results compared to those presented in the technical literature. Increase in the index of refraction beyond about 2.3 by means of increasing the gas flow did not reduce the residual stress appreciably but had a significant detrimental impact on the thickness uniformity and deposition rate. In contrast to results reported by other researchers, uniformity was not observed to increase with increasing DCS/NH3 ratio in this study. Efforts to minimize thickness non-uniformity by suppressing deposition rate at the gas inlet region of the deposition system while increasing deposition rate at the rear were not successful. While increasing the temperature at the exhaust end of the system was intended to improve thickness non-uniformity, significant thickness and index of refraction uniformity was not realized. The reduction in deposition rate and corresponding increase in index of refraction at the exhaust end of the system indicated a variation in gas species from inlet to exhaust of the system. These experimental results revealed that the index of refraction decreased while the deposition rate decreased with increasing partial pressure of DCS. This suggests that the inhomogeneity observed within the repeatability runs is due to ammonia depletion along the length of the load. (C) 2002 Elsevier Science Ltd. All rights reserved.