Patent ID: 9159813
Filing Date: 2015-10-13
Classification: H01L

Abstract:
1. A method for manufacturing a nonvolatile semiconductor memory including a floating gate arranged so as to surround an outer periphery of an island-shaped semiconductor with a tunnel insulating film interposed between the floating gate and the island-shaped semiconductor, a control gate arranged so as to surround an outer periphery of the floating gate with an inter-polysilicon insulating film interposed between the control gate and the floating gate, and a control gate line electrically connected to the control gate and extending in a predetermined direction, the method comprising: a step of forming a plurality of island-shaped semiconductors on a source line formed at a predetermined position on a substrate; a step of forming an insulating film between the plurality of island-shaped semiconductors that are adjacent to each other and on the source line; a step of forming a floating gate film by depositing a conductive material on the insulating film; a step of forming a resist on the floating gate film, the resist having a groove extending in a direction perpendicular to the predetermined direction in which the control gate line extends; a step of forming the floating gate for each of the plurality of island-shaped semiconductors using the resist by separating the floating gate film from a portion that is a lower region of the groove and that is on the insulating film by etching; a step of forming the control gate for each of the plurality of island-shaped semiconductors, above two floating gates of adjacent island-shaped semiconductors among the plurality of island-shaped semiconductors, so as to surround the outer periphery of the island-shaped semiconductor; and a step of forming the control gate line to connect the control gates of adjacent island-shaped semiconductors among the plurality of island-shaped semiconductors.