Deep trench isolation forming method of CIS device, and semiconductor device structure

Abstract

The invention discloses a deep trench isolation forming method of a CIS device, and a semiconductor device structure, and relates to the field of semiconductor manufacturing. The method comprises the following steps: growing a first epitaxial layer on a substrate; forming a hard mask layer; forming a plurality of deep grooves which are arranged vertically and horizontally in the first epitaxial layer; forming a second epitaxial layer in the deep trench; forming a first oxide layer on the surface of the second epitaxial layer in the deep trench; fully filling the deep trench with polycrystalline silicon; performing back etching on the substrate to expose the side wall of the first oxide layer in the deep trench; forming a second oxide layer on the top of the polycrystalline silicon; removing the first oxide layer above the hard mask layer and the second oxide layer; rapidly growing a third epitaxial layer; and performing CMP processing on the surface of the substrate, and forming deep trench isolation on the substrate. The problem that when deep trench isolation of a CIS device is formed in an epitaxial growth mode, the top of a deep trench crossing area is prone to having a sealing defect is solved. The formation process of the deep trench isolation is optimized, and the device performance is improved.

Description

technical field [0001] The present application relates to the field of semiconductor manufacturing, in particular to a method for forming deep trench isolation of a CIS device and a structure of a semiconductor device. Background technique [0002] CIS (CMOS Image Sensor, image sensor) is a device that converts optical signals into electrical signals. Due to the advantages of high integration, low power, and low cost, CIS devices are more and more widely used. [0003] The sensitivity of the CIS device is strongly related to the size of the pixel area. In order to increase the sensitivity of the small-sized pixel area, it is necessary to expand the space of the photodiode in the vertical direction. At present, when forming the pixel area of ​​a CIS device, the pattern of the pixel area is firstly defined by a photolithography process, and then the pixel area is formed by an ion implantation process. [0004] For small-sized pixel areas, the aspect ratio of the photoresist ...

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Problems solved by technology

[0004] For the small-sized pixel area, it will be limited by the aspect ratio of the photoresist during photolithography, and the depth and concentration of ion implantation during ion implantation. Existing materials are difficult to meet the process requirements

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