Multirow writing method for massively-parallel electron-beam systems

Electron-beam (e-beam) systems with a large number of beams have been developed in order to improve the writing throughput. It is desirable to have a writing method which can control beams to achieve not only a high throughput but also a high quality of writing. In a massively-parallel e-beam system, it is unavoidable that some beams are faulty and the current may vary with the beam. An important issue is how to mitigate the effects of faulty beams and current variation to enhance the quality of a transferred pattern. A possible way to reduce the negative effects of faulty beams is to spread the effects spatially. In this paper, a writing method, referred to as multirow writing, which uses each beam to expose pixels over multiple rows in each writing path, is proposed and the general procedures of realizing the method is described. The multirow writing method minimizes the dose reduction at a pixel and localization of affected pixels without exposing each writing path multiple times.