Application of ion implantation technology in CCD fabrication and CCD fabrication technology

Abstract

The invention discloses application of ion implantation technology in CCD fabrication. The ion implantation technology is a conventional ion implantation doping process used for fabricating polysilicon gates of other devices, wherein the other devices are not CCDs. The ion implantation technology is mainly characterized in that when the polysilicon gates on the CCD are fabricated, the conventional ion implantation doping process is adopted to perform phosphorus ion implantation doping processing on the polysilicon gates on the CCD. The application of the ion implantation technology in the CCD fabrication and the CCD fabrication technology have the benefits that the technology capability during the CCD fabrication is improved, multiple problems of the prior art are solved, the performance and the quality of the CCD are ensured, and the technical foundation is provided for processing the CCD with high quality.

Description

technical field [0001] The invention relates to a CCD manufacturing technology, in particular to an application of an ion implantation process in CCD manufacturing and a CCD manufacturing process. Background technique [0002] In the semiconductor industry, the existing doping technologies generally include thermal diffusion doping and ion implantation doping; thermal diffusion doping is widely used in the production of polysilicon gates in various semiconductor devices (including the production of CCDs), The ion implantation doping is generally used for the production of polysilicon gates of non-CCD devices, and the technology of ion implantation doping is very mature, and the equipment is very complete; among them, the application of thermal diffusion doping in the production of CCD devices is as follows: [0003] The polysilicon gate has two main functions in the CCD device, one is as the charge transfer control gate, and the other is as the amplifier MOS gate electrode; ...

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Problems solved by technology

[0005] 2. High-temperature phosphorus diffusion will cause junction push effect. In the CCD manufacturing process, in order to realize the function of charge generation and transfer, multiple ion implantations must be performed before polysilicon gate fabrication, and the subsequent high-temperature phosphorus diffusion process will bring junction push. Effect, especially for low-energy shallow junction implantation, the actual junction depth after high-temperature phosphorus diffusion has a large deviation from the design value, and the device parameters are difficult to meet the standard, resulting in low yield;

[0006] 3. When high-temperature phosphorus is diffused, due to the limitation of process conditions, it is difficult to control the uniformity of doping, and the non-uniformity of impurities doped in polysilicon is relatively large, which will eventually lead to a decrease in the uniformity of CCD output;

[0007] 4. The high-temperature phosphorous diffusion doping process will cause the polysilicon grains to become larger, which is not conducive to the control of polysilicon line width, and will also affect the quality of CCD;

[0008] 5. The process of high-temperature phosphorus diffusion is complicated; the high-temperature phosphorus diffusion polysilicon gate doping process can be simplified as follows: polysilicon deposition → high temperature phosphorus diffusion doping → bleached phosphorus silicon glass → cleaning process → polysilicon photolithography → polysilicon etching → Polysilicon is oxidized, and finally a single-layer polysilicon gate is formed; in the above-mentioned process, in order to ensure the cleanliness of the device surface, it is generally required that the time interval between high-temperature phosphorus diffusion doping and phosphorous-silicate glass should not exceed 1 hour. The furnace tube doping method is adopted, and the time for removing the furnace tube and cooling time is removed, leaving very little operating time for phosphosilicate glass rinsing, resulting in very tight rinsing time for phosphosilicate glass, which is prone to unclean rinsing of phosphosilicate glass, affecting Subsequent photolithography process, which affects the quality of CCD

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