Trench power device and manufacturing method

Abstract

The invention discloses a trench power device and a manufacturing method. A first trench is formed in a semiconductor substrate, a first blocking layer and a filling material layer are arranged in the first trench, an electrostatic isolation structure is formed, the fact that the electrostatic isolation structure is arranged in the semiconductor substrate is further realized, a condition in which the electrostatic isolation structure is higher than a second trench and a third trench can be avoided, the semiconductor substrate can have a flat surface, problems that due to the traditional rough electrostatic isolation structure, a step coverage ability in the subsequent deposition process is poor, particularly, bad resist uniformity and abnormal exposure happen to lithography, the resist at the step is thin and cannot be used as an etching blocking layer effectively and the like can be effectively solved, and through enabling the electrostatic isolation structure to be formed by a first filling material layer and a second filling material layer deposited at different times, the electrostatic isolation structure with a high-performance ESD ability can be acquired, the device structure is realized, and the parameters and the reliability meet requirements of the product.

Description

technical field [0001] The invention relates to the field of semiconductor equipment, in particular to a trench power device and a manufacturing method. Background technique [0002] In semiconductor technology, power discrete devices include devices such as power MOSFETs, high-power transistors, and IGBTs. Early power devices were produced based on planar technology, but with the development of semiconductor technology, small size, high power, and high performance have become the trend of semiconductor development. The trench technology changes the channel from horizontal to vertical, eliminates the influence of the parasitic JFET resistance of the planar structure, greatly reduces the size of the cell, increases the density of the original cell on this basis, and increases the total width of the channel per unit area of ​​the chip. It can increase the channel width-to-length ratio of the device on a unit silicon wafer, so that the current increases, the on-resistance decr...

AI Technical Summary

Problems solved by technology

[0006] An object of the present invention is to provide a trench power device and its manufacturing method, which solves the problem that the unevenness of the semiconductor substrate surface caused by the traditional electrostatic isolation structure affects the step coverage of the subsequent deposition process, especially the poor uniformity of the photolithography. , the exposure is abnormal, the photoresist at the step is too thin and cannot be effectively used as an etch barrier layer, etc.

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