Method for forming charge storage electrodes of semiconductor device

A method for forming charge storage electrodes of a semiconductor device, comprising the steps of:

• forming an interlayer insulating film over a semiconductor substrate;
• removing portions of the interlayer insulating film disposed above portions of the semiconductor substrate, each defined as a charge storage electrode contact, thereby forming charge storage electrode contact holes;
• forming a first polysilicon layer over the resulting structure obtained after the formation of the charge storage electrode contact holes such that the first polysilicon layer is in contact with the semiconductor substrate through the charge storage electrode contact holes;
• forming a charge storage electrode mask on the first polysilicon layer, thereby protecting portions of the first polysilicon layer respectively filling the charge storage electrode contact holes;
• removing portions of the first polysilicon layer not covered with the charge stolage electrode mask, thereby partially exposing the interlayer insulating film;
• selectively growing an oxide film over each exposed portion of the interlayer insulating film such that the selectively-grown oxide film is upwardly protruded beyond the upper surface of the charge storage electrode mask;
• removing the charge storage electrode mask;
• forming a second polysilicon layer over the resulting structure obtained after the removal of the charge storage electrode;
• anisotropically full-etching the second polysilicon layer such that the second polysilicon layer has portions separated flom one another, thereby forming charge storage electrodes each constituted by the first polysilicon layer pattern in contact with the semiconductor substrate through each corresponding charge storage electrode contact hole and the second polysilicon layer pattern disposed above the first polysilicon layer pattern while being in contact with the first polysilicon layer pattern, the second polysilicon layer pattern having bent portions.