Method for forming deep trench and shallow trench in trench network and semiconductor device thereof

The invention discloses a method for forming a deep trench and a shallow trench in a trench network and a semiconductor device thereof, relates to a method for forming a power semiconductor device, and aims to solve the problem of poor formation of the deep trench and the shallow trench in the prior art. A transition area with a protection effect is reserved at the joint of the formed deep groove and the shallow groove; and then continuously etching to increase the widths of the deep trench and the shallow trench until the deep trench and the shallow trench in the chip are connected with each other, and etching the position of the transition region in the step to form a convex transition region. According to the invention, the process control difficulty of photoetching and groove etching in the manufacturing process is reduced, and the uniformity and consistency of the groove are improved. 沟槽网络中深沟槽和浅沟槽的形成方法及其半导体器件，本发明涉及于功率半导体器件的形成方法，为解决现有技术形成深沟槽和浅沟槽的不良，本发明首先在硬掩模的保护下形成深沟槽和浅沟槽，形成的深沟槽和浅沟槽连接处保留有起保护作用的过渡区域；然后继续刻蚀增