Method for preparing backside-illuminated sensor

Abstract

The invention relates to the technical field of semiconductor manufacture, particularly to a method for preparing a backside-illuminated sensor. After a metal grid bottom bonding layer and metal layer film-coating process, a vacuum breaking process and a surface cleaning treatment process are performed on a semiconductor substrate in sequence, then an anti-reflection layer is deposited on the metal layer, and finally a plurality of metal grids whose upper surfaces have anti-reflection layers are formed through patterning and etching, thereby avoiding an abnormal projection phenomenon in a reverse side metal grid layer process, reducing abnormal growth, avoiding extra light crosstalk between different pixels, and improving performance of a backside-illuminated sensor chip.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a preparation method of a back-illuminated sensor. Background technique [0002] With the rapid development of semiconductor technology, semiconductor devices are used in various electronic applications such as personal computers, mobile phones, digital cameras, and other electronic equipment. Among them, a backside illuminated (BSI) sensor is a CMOS image sensor in which light enters the substrate from the backside of the substrate instead of the front side. Because of reduced light reflections, BSI sensors are able to capture more image signals than front-illuminated sensors. At present, the back-illuminated sensor, as a kind of camera chip, has occupied most of the market, and the process optimization of the metal grid layer on the back has been studied; the metal grid of the back-illuminated sensor is opaque, Thereby, the crosstalk of light between diffe...

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Problems solved by technology

At present, the back-illuminated sensor, as a kind of camera chip, has occupied most of the market, and the process optimization of the metal grid layer on the back has been studied; the metal grid of the back-illuminated sensor is opaque, Thereby, the crosstalk of light between different pixels (photodiodes) can be prevented; but there have been some problems in this metal grid layer process, wherein the metal grid layer may form abnormal protrusions during the growth and annealing process, which will cause Extra light crosstalk between different pixels; thereby affecting the performance of back-illuminated sensor chips; which is undesirable for those skilled in the art

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