A semiconductor device with trench gate and manufacturing method thereof

Abstract

The invention provides a semiconductor device with a trench gate and a manufacturing method thereof. The method comprises the following steps: after a patterned photoresist layer is formed, performingion implantation on a dielectric layer with partial thickness or total thickness; forming a dielectric damage layer in the dielectric layer, carrying out wet etching on the dielectric layer with thedielectric damage layer and further carrying out wet etching or dry etching on the doped region below and the body region with partial thickness to form contact hole. In the process of wet etching ofa dielectric layer with a dielectric damage layer, the dielectric damage layer and the dielectric layer around the dielectric damage layer have a high etching selection ratio. Therefore, the process difficulty can be reduced, the transverse etching can be reduced, the morphology of the finally manufactured contact hole can be improved, the distance between the bottom of the formed contact hole andthe trench type gate can be ensured, and the performance of the finally manufactured trench type semiconductor device can be improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a semiconductor device with a trench gate and a manufacturing method thereof. Background technique [0002] At present, the technology of IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) and VDMOS (Vertical Double-diffused MOSFET, vertical channel double-diffused metal oxide transistor) is constantly innovating, and the size of power semiconductor devices is constantly being realized. Under the premise of shrinking, the excellent performance of power semiconductor devices is also guaranteed. [0003] In the manufacturing process of the existing trench type IGBT transistor, it is necessary to transfer the design pattern of the contact hole from the mask plate to the wafer (i.e., the substrate) by means of a photolithography process and an etching process after the trench type gate is completed. ), specifically, a patterned photoresis...

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Problems solved by technology

However, as the size of semiconductor devices becomes smaller and the technical specifications become higher and higher, the critical dimension (CDsize) reserved for the small-sized IGBT transistor device structure from the contact hole to the gate trench on the design side gradually becomes smaller. When using wet etching to form contact holes, there are the following problems that affect the performance of the fabricated IGBT transistor device: 1) the process is difficult due to the reduction of critical dimensions; 2) wet etching is isotropic , when wet etching reaches the required depth of the contact hole, the accompanying lateral etching will often be too much, which will cause the distance between the contact hole formed after wet etching and the gate trench to be too small, which will lead to subsequent contact holes. Impurities implanted in the hole will diffuse to the channel region after annealing, thereby increasing the threshold voltage of the IGBT transistor device

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