An Integrated Process for Reducing White Pixels of CMOS Image Sensors

Abstract

The present invention discloses an integrated technology of reducing CMOS image sensor white pixels. The integrated technology comprises the steps of forming the shallow trench isolation in a matrix; growing a pad oxide layer and a silicon nitride barrier layer orderly on the surface of the matrix; coating a photoresist, taking the graphical photoresist as the barrier layer, and penetrating the silicon nitride barrier layer to carry out the ion implantation on the matrix to form a photodiode and an isolation area around the photodiode in the matrix; removing the silicon nitride barrier layer and the pad oxide layer, and then growing a gate oxide layer and a polycrystalline silicon layer; forming a polycrystalline silicon transmission gate and a side wall, and carrying out the shallow-layer ion implantation; forming an interlayer dielectric and a metal layer. The silicon nitride barrier layer can block the ion implantation, especially can block the metal impurities introduced by the metal elements volatilized by the electronic shower during a high energy ion implantation process, at the same time, can reduce the crystal lattice defects caused by an arc effect when the ions are implanted in a shallow-layer area, thereby reducing the white pixels effectively.

Description

technical field [0001] The invention relates to the technical field of semiconductor integrated circuit manufacturing, and more particularly, relates to an integration process for reducing white pixels of a CMOS image sensor. Background technique [0002] In recent years, with the rapid development of mobile networks, mobile smart terminals have been widely popularized and constantly updated. The image sensor, which is the "eye" of the mobile terminal, is also following the market demand and constantly improving its performance. [0003] The future direction of image sensor development is high pixel, low power consumption, and high image quality. High pixel count and low power consumption require continuous reduction in pixel size. However, as the pixel size shrinks, the quality of the pixel drops dramatically, especially the quantum efficiency and noise. Quantum efficiency can be compensated by high-energy ion implantation to elongate the photodiode depth, but noise redu...

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Problems solved by technology

Although these measures can reduce the number of white pixels, the process control is very difficult, because a very low concentration of metal contamination can cause a sharp increase in white pixels

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