Patent ID: 6383869
Filing Date: 2002-05-07
Classification: H01L

Abstract:
A method of forming a semiconductor device, comprising the steps, in the stated order, of:forming a first oxide film (8) over a top surface of an inter-layer insulator (7); forming a first nitride film (9) over a top surface of said first oxide film (8), wherein the first nitride film (9) is different in etching selectivity from said inter-layer insulator (7); forming at least a contact hole (11) which penetrates said first nitride film (9), said first oxide film (8) and said inter-layer insulator (7); depositing a second oxide film (12-a) on an upper surface of said first nitride film (9) and on side walls and a bottom of said at least a contact hole (11); carrying out an etch-back process by use of said first nitride film (9) as an etching stopper for selectively etching said second oxide film (12-a) over said first nitride film (9) and on the bottom of said at least a contact hole (11) to form side wall oxide insulators (12-b) on the side walls of said at least a contact hole (11), wherein said etch back process is discontinued just when a top level of said side wall oxide insulators (12-b) lie lower than a top surface of said first oxide film (8) and higher than a bottom surface of said first oxide film (8); removing said first nitride film (9); filling said at least a contact hole (11) with a polysilicon film, so that said polysilicon film is completely isolated from said the inter-layer insulator (7) by said side wall oxide insulators (12-b) and said first oxide film (8); patterning said polysilicon film to form a polysilicon storage electrode (13); subjecting an exposed surface of said polysilicon storage electrode (13) to a wet etching to form an uneven surface defined by hemispherical grains of polysilicon of said polysilicon storage electrode (13); forming a dielectric film (15) in contact with said uneven surface of said polysilicon storage electrode (13); and forming an opposite electrode (16) on said dielectric film (15) to form a storage capacitor.