Improvement of Bending Failure in DRAM Capacitors through The Utilization of EUV Patterning

As the size of the dynamic random access memory(DRAM) continues to shrink, the difficulty of patterning has become increasingly challenging. Among them, the capacitor pattern, an essential element for data storage, possesses the structure with the highest aspect ratio in DRAM. Consequently, difficulties in securing yield arise due to the chronic defects such as bending and pattern collapse of the pillar-type capacitor node, impeding the overall manufacturing process. Bending of the capacitor node, generating bridges in the bottom electrodes, serves as a disruptive factor that hinders the normal operation of the memory. The bending of the capacitor occurs due to stress induced by bottom electrode oxidation during the deposition of the dielectric layer after the deposition of the bottom electrode. To prevent this, a supporter structure is being introduced. The supporter is composed of a nitride layer and is patterned for the deposition of the dielectric layer on the bottom electrode. The impact on capacitor bending varies depending on the patterning of this supporter. In this research, the improvement in capacitor bending was confirmed through the application of all cell open(ACO) supporter patterning using extreme ultraviolet(EUV). Through this, we suggests the ultimate patterning fabrication process for DRAM capacitors to overcome the scaling limits of DRAM, opening up the inevitable possibility of the EUV era, ensuring the realization of sub-10nm patterns with high guarantee.