Beam Scanning Controller for Proton-Beam Writing

Abstract

A scanning control system of the ion beam of MeV energies has been developed for the nuclear scanning microprobe and proton-beam writing channel as a part of accelerator-analytical complex based on the Sokol electrostatic accelerator of the Institute of Applied Physics of the National Academy of Sciences of Ukraine. The system was put into operation to replace the obsolete one based on microcontrollers. The scanning control system is based on a National Instruments reconfigurable module with a Field Programmable Gate Array. The module operates in real time and is connected to a personal computer by a high-speed PCI-Express interface with data buffering. The system provides two main modes of operation: exposure of sample areas with a given profile and raster secondary electrons imaging of the sample or a calibration grid. Profile exposure is possible both in raster and functional scanning modes. Automatic calibration of the profile scale and scan raster is also implemented. Using of reconfigurable logic makes it possible to quickly adjust the system to the conditions of a particular experiment and the available equipment. The hardware capabilities of the scanning control system allows in the future to connect up to 4 spectrometric ADC for mapping the elemental composition of samples using Proton Induced X-ray Emission and Proton Backscattering. The first experiments on the irradiation of polymethylmethacrylate have been carried out; images of the obtained microstructures taken with a scanning electron microscope are shown. The aim of this work is to develop a control system for scanning a high-energy focused beam in proton beam writing technique to create small-sized structures for special purposes, as well as to demonstrate the efficiency of the developed system.

Keywords

• lithography
• proton beam writing
• scanning control
• nuclear microprobe