Method for Placing a Passing Word Line Above a Trench Strap
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
A complementary metal-oxide-semiconductor (CMOS) dynamic random-access memory (DRAM) cell structure which permits a polysilicon line to be passed over a diffusion region without forming a field-effect transistor (FET) is reported. By using this structure, a word line can cross a cell's trench strap region and significantly reduce the cell area. A process method is utilized for reducing a DRAM cell's word line pitch by passing the word line above the cell trench strap to accommodate more dense chip designs. The process also allows a polysilicon line to cross over a diffusion without the use of contacts or metal strap and without forming a FET. Fig. 1 shows a layout for storage cells where the word line passes over the storage cell trench structure.