FLASH MEMORY DEVICE AND FORMING METHOD THEREOF

摘要

PURPOSE: A flash memory device and a forming method thereof are provided to increase the coupling ratio between a floating gate and a control gate by deeply forming a contact hole without the limitation for height according to a bit line. CONSTITUTION: A flash memory device is provided with a floating gate, a control gate(91) on the floating gate, and a bit line(75) spaced apart from one side of the floating gate. The floating gate includes a lower floating gate(61) on a substrate(41) and an upper floating gate(87) opposite to the control gate in a contact hole. The contact hole has a desired depth. The upper floating gate is formed like a sidewall spacer. A dielectric layer(89) is between the upper floating gate and the control gate. The floating gate further includes a connection plug(81) through an interlayer dielectric for connecting the lower floating gate with the upper floating gate.