Submicrometer Electron-Beam Direct Writing Technology for 1-Mbit DRAM Fabrication

A 1-Mbit DRAM with 0.5-μm minimum linewidth is fabricated using variable shaped e-beam direct writing technology. A simple linewidth control technique using newly developed submicrometer resists is developed to achieve high resolution and better linewidth accuracy. In addition, a highly accurate registration technique is developed to ensure required overlay. These techniques are successfully used to achieve overlay accuracy of 0.04 μm(sigma) and linewidth deviation of 0.018 μm(sigma) in the fabrication.