A HIGH-ACCURACY AND HIGH THROUGHPUT ELECTRON-BEAM RETICLE WRITING SYSTEM FOR 16M DYNAMIC RANDOM-ACCESS MEMORY CLASS AND BEYOND DEVICES

A new electron beam reticle writing system has been developed for a 16-256M dynamic random access memory (DRAM) class reticle pattern making. A continuously moving stage, variable-shaped beam and vector-scanning method has been adopted. The acceleration voltage was varied from 20 to 12.5 kV. An acceleration voltage of 15 kV provided proximity effect correction free exposure for reticle patterns larger than 2-mu-m corresponding to the minimum feature size of 16M DRAM class devices. A single reticle processing autoloader has also been developed for quick turn around time. Parallel processing of data conversion has enabled the system to convert Gaussian beam system data to the new variable shaped beam system data of 10 MB volume in about 20 min.