Optimization of pattern shape in electron-beam cell projection lithography

In electron-beam cell projection lithography, it is important to achieve high resolution and high throughput enough for use in mass production. Mask bias method has been demonstrated to be very effective in improving both performance. However, factors of mask bias effects have not been clarified. In this paper, we have analyzed the factors of the mask bias effects and have discussed a method for estimating the optimum bias. We have found that the decrease of beam blur due to the Coulomb interaction and expansion the space of streams to decrease the beam overlapping neighboring each other are the main factors and that the back-scattering effect can be negligible. Finally, we have derived and proposed a method for obtaining the optimum mask bias that produces high resolution and high throughput.