Manufacturing method of low-voltage high-density trench DMOS device

Abstract

The invention discloses a manufacturing method of a low-voltage high-density trench DMOS device, which belongs to the technical field of semiconductor power devices. After the trench array is completed, sacrificial oxidation to repair the damage of the inner surface of the trench array is directly performed without removing the oxide layer. The surface of the polycrystalline silicon in the trencharray is 2000-3000 angstroms higher than the surface of the silicon. And through an oxide layer etching technology, the oxide layer on the surface of the silicon is removed through dry etching, and the residual oxide layer with a certain thickness is taken as a well injection barrier layer. The masking oxide layer in trench array etching is used for raising the height of the polysilicon at the gate lead-out position, so that the polysilicon is prevented from being perforated by hole corrosion, and the product yield and reliability are improved; by optimizing the process, the problem of short circuit of gate polycrystalline silicon perforated through a gate contact hole is reduced, so that the product yield and the reliability are improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor power devices, in particular to a method for manufacturing a low-voltage high-density trench DMOS device. Background technique [0002] With the continuous expansion of the application field of VDMOS products and the continuous improvement of process line capabilities, the industry's requirements for product energy efficiency are also getting higher and higher. Ordinary low-voltage Trench DMOS products, because the channel resistance accounts for a large proportion, the optimization direction is to reduce the size of the original cell and the shallow junction process of the channel. Taking N20V products as an example, the original cell unit of mass products on the market has been reduced to 0.9um, and the well depth is about 0.5~0.7um. The gate electrode of this product is generally drawn out at the edge of the die through a large trench. Under the current process conditions, due to the hig...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a low-voltage high-density trench DMOS device manufacturing method to solve the problem that the current process is easily pierced by the hole when the gate polysilicon leads to the contact hole, resulting in low product yield.

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