Electron-Beam Reticle Writing System For 16M Dram Class Devices

Based on our present understanding of the recent progress in optical technology, it appears that wafer steppers will be applicable for the production line up to 16M DRAM having 0.5 μm design rule or so. From this point of view, we have concluded that E-beam system promising the production of high quality reticles is mandatory necessary in the field. For the back-ground mentioned above, Toshiba has developed the new conceptual E-beam system designated EBM-160/80. This paper describes the design concept and system outline on EBM-160/80. The most essential requirements of this type of system, such as raster scan, round Gaussian beam and continuous moving stage, are to make CD increment smaller, simultaneously to get high production throughput and reasonable accuracy. Employing high speed bit data generating processor (HBG), we have completed high production throughput E-beam system which means throughput free from reticle pattern complexity. As a result, it takes about 40 min. at 0.25 μm address size or 250 min. at 0.1 pm address size for 5X, approx. 80 mm x 90 mm reticle with several millions of pattern. EBM-160/80 has capability to produce high quality reticle for up to 16M DRAM. In order to realize enough accuracy, the new technologies have been developed and integrated. As a result, we could achieve our accuracy target, butting accuracy 0.05 pm, CD control 0.1 μm, overlay accuracy 0.1 pm, scan linearity 0.05 μm.