Forming method of high-voltage field plate

Abstract

The invention relates to a manufacturing process of a semiconductor integrated circuit, in particular to a forming method of a high-voltage field plate. The method comprises the following steps: providing a substrate layer; forming a gate oxide layer on the substrate layer; sequentially depositing and forming a first dielectric layer and a second dielectric layer on the gate oxide layer; performing photoetching, and defining an active region and a terminal region for the first time; sequentially etching the second dielectric layer and the first dielectric layer to form a dielectric layer stepstructure, and forming an upper step of the dielectric layer step structure at the initially defined active region; depositing a third dielectric layer to enable the third dielectric layer to cover the dielectric layer step structure; etching the third dielectric layer to form an etching compensation structure at the bottom of the side wall of the upper step; performing isotropic etching on the dielectric layer step structure by using a wet etching process; defining a field plate region, and manufacturing a field plate structure in the field plate region to enable the field plate structure tocover the surface of the side wall of the first dielectric layer. The method can solve the problem of a high-voltage field plate structure formed in related technologies.

Description

technical field [0001] The present application relates to a semiconductor integrated circuit manufacturing process, and in particular to a method for forming a high-voltage field plate. Background technique [0002] In the semiconductor process, the usual preparation method of the PN junction is to use silicon dioxide as a mask to dope impurities into the silicon at the window by ion implantation and other methods. At the same time, it is accompanied by lateral movement, so that the final formed PN junction has a curved surface junction. Since the electric field at the curved surface junction is larger, the device is easy to break down at the curved surface of the PN junction. Usually, a field plate structure is added to the device to increase the breakdown voltage of the device. [0003] The formation method of the high voltage field plate in the related art is prone to the problem that the surface of the field plate area is not smooth after etching, so that the surface of...

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Problems solved by technology

[0003] The high-voltage field plate formation method in the related art is prone to the problem that the surface of the field plate area is not smooth after etching, so that the surface of the final formed high-voltage field plate structure is not smooth, thereby affecting the performance of the high-voltage field plate

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