A TVS with deep trench isolation structure and its manufacturing method

Abstract

The invention provides a TVS (Transient Voltage Suppressor) with a deep trench isolation structure, which comprises a substrate and an epitaxial layer with the type being opposite to that of the substrate, and is characterized in that the epitaxial layer is provided with a doping layer with the type being the same as that of the substrate, the periphery of the TVS is provided with an annular deep trench, the deep trench is filled with an insulation medium, the doping layer at the inner side of the deep trench is provided with a contact hole, metal is led out to act as a first electrode, the doping layer is covered with an interlayer dielectric to isolate the first electrode and the deep trench, the first electrode is provided with a passivation layer, and the passivation layer is provided with a hole used for leading out the first electrode; metal is led out from the back of the substrate to act as a second electrode; and the deep trench runs through the doping layer and the epitaxial layer and extends to the substrate. According to the invention, side isolation of a PN junction is realized, and the PN junction is filled with an insulating material so as to reduce side electric leakage of the PN junction; the mode of deep trench isolation is adopted, the occupied area is small, and the size of a chip can be significantly reduced; and the epitaxial thickness is small, a rebound is achieved in reverse conduction, the avalanche breakdown electric leakage is smaller than an ordinary PN junction, and the conduction is faster.

Description

technical field [0001] The invention relates to a semiconductor device, in particular to a TVS with a deep trench isolation structure and a manufacturing method thereof. Background technique [0002] With the continuous development of the market, TVS (Transient Voltage Suppressor, Transient Voltage Suppressor) has gradually developed into a circuit structure composed of individual independent devices (such as diodes, transistors, etc.) connected through specific electrical pathways, so in its manufacturing It must be possible to isolate individual individual devices which can then be interconnected to form the specific circuit structure required. Poor isolation will cause problems such as leakage and low breakdown. Therefore, isolation technology is a key technology in the production of TVS. [0003] The existing isolation process technologies are as follows: [0004] 1. PN junction isolation [0005] Generally, it is realized by diffusing on the N-type epitaxial layer o...

AI Technical Summary

Problems solved by technology

[0019] In order to overcome the defects of large PN junction isolation leakage and capacitive effect that are not conducive to reducing the size of the device in the existing technology; at the same time, in order to overcome the LOCOS isolation loss active area, the surge capability of the transient voltage suppressor is reduced and the leucorrhea effect is caused. The problem of the drop in breakdown voltage and the problem of the transient voltage suppressor that the shallow trench STI isolation cannot penetrate the longitudinal structure, the present invention provides a TVS with a deep trench isolation structure and its manufacturing method

Images