Method for preparing semiconductor silicon wafer, silicon wafer and image sensor

Abstract

The invention provides a method for preparing a semiconductor silicon wafer, a semiconductor silicon wafer and an image sensor. The method includes: providing a semiconductor silicon wafer; laying a layer of photoresist on the surface of the semiconductor silicon wafer, and patterning the photoresist agent to form a photoresist having a plurality of parallel strip patterns disposed at equal widths; etching the semiconductor silicon wafer by using the photoresist as a barrier layer to form a W-shaped shallow trench on the surface of the semiconductor silicon wafer; and etching the sidewall of the W-shaped shallow trench to form a wavy structure on the surface of the semiconductor silicon wafer. The method increases the surface area of the semiconductor silicon wafer and increases a light absorption rate, thereby improving the optical performance of the image processor.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for preparing a semiconductor silicon wafer, a silicon wafer and an image sensor. Background technique [0002] As the market demand for a small-sized, high-pixel CMOS image sensor (CMOS Image Sensor, CIS) increases, so does the requirement for its optical performance. However, due to the inherent limitations of the high reflectivity of visible light-infrared light on the silicon surface, CIS cannot achieve the maximum absorption of light. This deficiency largely limits the optical performance of CIS. [0003] The traditional CIS process will go through silicon thinning and planarization process, deposit high dielectric film (HiK filmdeposition, HiK DEP) and buffer oxide layer (Buffer Oxide, BFOX), metal grid (Backside metalgrid, BMG) and subsequent open metal Wire connection area (Pad open) process. The flat silicon Si surface has greater reflectivity for visi...

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Problems solved by technology

[0005] Aiming at the defects in the prior art, the present invention provides a method for preparing a semiconductor silicon wafer, a silicon wafer and an image sensor, so as to solve the problem that the image sensor has a low light absorption rate in the prior art, which greatly restricts the device The problem of optical performance

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