The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 06, 2025
Filed:
Aug. 18, 2022
Shanghai Huali Microelectronics Corporation, Shanghai, CN;
Shanghai Huali Microelectronics Corporation, Shanghai, CN;
Abstract
The present application discloses a method for preparing a pixel cell of a CMOS image sensor. Process optimization and adjustment for multiple times of ion implantation in a pixel area of the CMOS image sensor are carried out. That is, photodiode N-type ion implantation is performed before formation of a polysilicon gate of each MOS transistor of a CMOS pixel readout circuit, a photoresist open area is enlarged by means of a photoresist dry etching descum process such that an N-type ion implantation area is enlarged, and second photodiode N-type ion implantation is performed on the basis of the photoresist dry etching descum process, so as to achieve two times of photodiode N-type ion implantation using the same mask, with different depths and different pattern sizes, thereby forming an N-type area of the photodiode that tapers to the bottom, saving a mask layer, and reducing photolithography steps.