Patent ID: 6830969
Filing Date: 2004-12-14
Classification: H01L

Abstract:
A method of manufacturing a semiconductor device, comprising the steps of:(a) forming a plurality of lower bit lines arranged in a first direction on a semiconductor substrate by performing ion implantation using a mask defining the lower bit lines; (b) forming a lower field oxide film within a region in which the lower bit lines are formed, thus defining an active region and a device isolation region; (c) forming a first insulating film for accumulating charges on the active region; (d) forming a plurality of word lines arranged in parallel in a second direction orthogonal to the first direction of the lower bit lines; (e) depositing an oxide film on the entire structure of the semiconductor substrate including the lower bit lines and the word lines, flattening the oxide film and then removing the oxide film on the word lines; (f) forming a second insulating film for accumulating charges corresponding to the first insulating film for accumulating charges on the word lines and then forming an upper field oxide film corresponding to the lower field oxide film on the word lines; (g) depositing polysilicon on the entire structure of the semiconductor substrate, performing ion implantation for polysilicon using a mask defining upper bit lines to form the upper bit lines, and then performing ion implantation using a mask defining an upper substrate to form the upper substrate; and (h) removing given portions of the upper bit lines formed on the upper field oxide film to separate the upper bit lines.