Preparation method of flash memory unit and preparation method of semiconductor structure

• Main Authors: LIU XIANZHOU, SHEN SIJIE
• Format: Patent
• Language: Chinese; English
• Published: 14.09.2018
• Subjects: ELECTRICITY

The invention provides a preparation method of a flash memory unit and a preparation method of a semiconductor structure. According to the preparation method of the flash memory unit, the length rangeof a floating gate in a flash memory unit to be formed is determined; a dielectric layer and a floating gate layer are etched, so that first openings are formed; the section widths of the bottoms ofthe first openings are measured; the first openings are filled with a polysilicon material; the dielectric layer is removed, so that a second opening is formed; and the section width of a first side wall is selected according to the length range of the floating gate and the section widths of the bottoms of the first openings; and first side wall is formed on the side wall of the second opening. When different flash memory units are separated from one another, so that the floating gate is formed, the floating gate layer at the bottom of the first side wall is etched with the first side wall adopted as a mask, and theref