Method of manufacturing a storage node having five polysilicon bars

摘要

A method for forming a dynamic random access memory cell with an increased capacitance capacitor having a storage node with five polysilicon bars is achieved. A photoresist mask is formed overlying a portion of a first polysilicon layer filling an opening through a dielectric layer to a node contact region. The photoresist mask is silylated to form a top silylated photoresist portion and silylated photoresist sidewalls on the surfaces of the photoresist mask. The top silylated photoresist portion and the unsilylated mask are removed. A portion of the first polysilicon layer is etched away where it is not covered by the silylated photoresist sidewalls thereby forming two first polysilicon bars underlying the silylated photoresist sidewalls and leaving a second thickness of the first polysilicon layer smaller than its first thickness. The silylated photoresist sidewalls are removed. A second dielectric layer is deposited over the first polysilicon layer and is anisotropically etched back to form spacers on either side of the two polysilicon bars. A second polysilicon layer is deposited and the first and second polysilicon layers are anisotropically etched back to form three second polysilicon bars and a T-shaped first polysilicon layer. The dielectric spacers are removed whereby the T-shaped first polysilicon layer and the two first polysilicon bars and three second polysilicon bars make five polysilicon bars which together form a storage node of the capacitor.