Novel Robust Cell Capacitor (Leaning Exterminated Ring type Insulator) and New Storage Node Contact (Top Spacer Contact) for 70nm DRAM technology and beyond

摘要

For the first time, novel robust capacitor (Leaning exterminated Ring type Insulator -LERI) and new storage node (SN) contact process (Top Spacer Contact -TSC) are successfully developed with 82nm feature size. These novel processes drastically improved electrical characteristics such as cell capacitance, parasitic bit line capacitance and cell contact resistance, compared to a conventional process. The most pronounced effect using the LERI in COB structure is to greatly improve cell capacitance without twin bit failure. In addition, the TSC technology has an ability to remove a critical ArF lithography. By using the LERI and TSC processes in 82nm 512M DDR DRAM, the cell capacitance of 32fF/cell is achieved with Toxeq of 2.3nm and the parasitic bit line capacitance is reduced by 20%, resulted in great improvement of tRCD(1.5ns).