Trench gate structure and fabrication method thereof

Abstract

The present invention relates to a trench gate structure and a fabrication method thereof. The trench gate structure includes a substrate, a trench on the surface of the substrate, an insulating liner on the substrate, a gate oxide layer on the inner surface of the trench, and a polysilicon gate on the gate oxide layer; the insulating liner adjoins the trench through the ramp structure of the insulating liner; the polysilicon gate extends along the ramp structure from the trench to the insulating liner; the insulating liner comprises a polysilicon gate lifting region which is recessed relative to the other portions of the liner; and the polysilicon gate extending out from the trench is supported on the polysilicon gate lifting region. According to the trench gate structure of the invention, a portion of the polysilicon gate in the trench is independent from a portion of the polysilicon gate which extends to the insulating liner, and therefore, the depth of the trench and the depth of a contact hole will not limit each other. The photo-etching of the polysilicon gate and polysilicon photo-etching of a device are performed in the same step, and therefore, additional photo-etching masks and photo-etching layers are not needed to be adopted, and cost increase can be avoided.

Description

technical field [0001] The invention relates to semiconductor manufacturing technology, in particular to a trench gate structure and a manufacturing method of the trench gate structure. Background technique [0002] Due to cost reasons, traditional trench-type vertical double-diffused metal-oxide-semiconductor field effect transistor (VDMOS) products mostly adopt the method of increasing the end size of the lead-out trench and punching contact holes on it to lead out the trench gate structure. ,Such as figure 1 shown. The advantage of this solution is that it can use the existing mask layer of the product process, without increasing the cost of the mask layer. However, its disadvantage is that it is limited by the technology such as trench depth, polysilicon thickness, and contact hole depth, which limits the application of this traditional solution. Contents of the invention [0003] Based on this, it is necessary to provide a relatively more flexible trench gate struc...

AI Technical Summary

Problems solved by technology

However, its disadvantage is that it is limited by the technology of trench depth, polysilicon thickness, contact hole depth, etc., which limits the application of this traditional solution.

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