IGBT深槽刻蚀氮化硅硬掩膜制作工艺研究

Fabrication of IGBT Deep Trench Silicon Nitride Hard mask

硅基深槽刻蚀是槽栅IGBT器件的基本结构,也是确保器件性能的关键工艺,氮化硅硬掩蔽膜质量对于硅基深槽刻蚀起着重要的作用.本文采用低压化学气相淀积(LPCVD)工艺淀积氮化硅薄膜,具有均匀性好,而且呈现较大的张应力,可以补偿二氧化硅缓冲层的压应力,有效地解决了硅-二氧化硅-氮化硅夹心结构的应力问题.分析比较了工艺参数,如气体流量、淀积环境的压强、温度等,对氮化硅薄膜生长速率及膜厚的影响,获得了氮化硅薄膜淀积的优化工艺参数.

Deep-trench is the basic structure for trench gate IGBT and also the key technology for guarantee the devices performance parameters.Silicon nitride thin film as the hard mask is very important for silicon deep trench etched.In this article,the silicon nitride thin film is fabricated using LPCVD(Low pressure chemical vapor deposition)processes with more uniform thickness,and more tensile stress which is effectively compensated the compressive stress of silicon oxide film,so the stress problem in sandwich structure of silicon/silicon oxide/silicon nitride is removed.The technology parameters,such as gas flow,pressure,and temperature etc.which are affected on deposition rate and thickness of silicon nitride film,are analyzed and compared,and acquired the optimized processes parameters for the silicon nitride film deposition.