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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