Trench type power semiconductor device and manufacturing method thereof

Abstract

The invention discloses a trench type power semiconductor device and a manufacturing method thereof, and relates to a power semiconductor device. In order to solve the problems that the manufacturingcost of a device is increased and the parasitic gate capacitance is increased due to the presence of a gate bus, the invention provides the following technical scheme: a gate contact hole is formed inan interlayer dielectric layer above the initial section of a trench, the gate conductive material in the trench is connected with the gate electrode metal layer above the gate conductive material through the gate contact hole, the width of the gate contact hole is smaller than that of the initial section of the trench, and the width of the initial section of the trench is larger than that of theextension section of the trench. The beneficial effects of the invention are that: according to the trench type power semiconductor device, stable and reliable grid connection can be realized on thebasis of not causing negative influence on the performance of the device; and by omitting a gate bus board, the photoetching process steps of the device are reduced, and the manufacturing cost of thedevice is reduced; and meanwhile, the gate parasitic capacitance introduced by the gate bus board is reduced, and the switching speed of the device is improved.

Description

technical field [0001] The invention relates to the structural design and manufacturing method of power semiconductor devices, especially trench power transistors, such as insulated gate bipolar transistors (IGBT) and power metal oxide semiconductor field effect transistors (Power MOSFET). Background technique [0002] Power transistors are a key component of power electronics systems and are widely used in various applications such as motor drives and power conversion. Generally, power transistors mainly include Power Metal Oxide Semiconductor Field Effect Transistors (Power MOSFETs), Insulated Gate Bipolar Transistors (IGBTs), etc. The former is mainly suitable for medium and low voltage (≤600V) low power systems, and the latter is mainly suitable for Medium and high voltage high power (≥600V) high power system. From the perspective of the structure of power transistors, there are mainly two structures, planar gate and trench gate. Among them, the trench gate structure ca...

AI Technical Summary

Problems solved by technology

However, in order to reduce the gate parasitic capacitance introduced by the trench (105) to accelerate the switching speed of the device, the surface area of ​​the trench (105) needs to be reduced, which leads to the narrower width of the trench (105) generally being set (about 1 μm), and in the process of device processing, there is often a certain alignment deviation in the contact hole photolithography process. If the contact hole on the gate trench deviates slightly, it will easily cause the gap between the gate and the emitter. Short circuit, the process risk is too high, and the use of high-precision photolithography alignment process will increase the difficulty and cost of device manufacturing, resulting in more losses than gains

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