Abstract: We present a new method to fabricate PMMA 1D and 2D periodic nanostructures at the tens-to-hundreds of nanometers scale using the calibrating sign of a digital scanning electron microscope (SEM).In our work,a controllable negative bias voltage generator is cascaded into the cathode self-bias-voltage circuits of SEM,and its internal resistance is far smaller than the self-bias-voltage resistance.The SEM works normally when the generator do not produce negative bias voltage.Once the negative bias voltage is generated,it will restrain electrons emitted from the cathode not passed the grid.The resulting patterning of PMMA-1D and 2D periodic nanostructures are formed by electron beam scanning in the modified SEM.

Key words: digital SEM, negative bias voltage generator, surface nanostructure array, e-beam lithography