Today I am enrolled to the postgraduation program (Electrical Enginnering/Microelectronics) at the University of São Paulo (USP) in Brazil and working with electron beam lithography. Working on this subject has given me experience with several characterization technics. Ellipsometry spectroscopy for thin film thickness measurement and scanning electron microscopy are some of the everyday technics. For background, a master degree on Physics at the State University of Campinas (UNICAMP) on optical properties of III-V strained superlattices (InGaAs/GaAs), specially with Raman, photoluminescence and photoreflectance modulation spectroscopy (earned at 1994) and a bachelor degree on Physics at UNICAMP (earned at 1991).
My research concentrates on two subjects: low energy e-beam lithography and sylilation of resists. The resists are PMMA (a standard resist for e-beam lithography) and SNR200 (a DUV resist). In Brazil there is enormous difficulties to import resists for e-beam, so we choose to work with a DUV resist. Top surface imaging (TSI) processes, that includes sylilation, are a kind of processes that attracted attention for its advantages, like improved resitance to plasma etch. It is being investigated for us, combining low energy e-beam lithography and using sylilation to obtain a dry etch developable process. A simulator with Monte Carlo for low energy electron scattering is under development to obtain further informations about the proximity effects and to optimize the exposure for low energy electrons. There is a parallel collaboration with another research group in Brazil under development (development of a process for submicrometer gate for GaAs HEMT transistor).
About the Monte Carlo simulator, it uses the Mott cross section to evaluate the scattering at low energy condition (< 10kV), that is more accurate than the Rutherford cross section. The calculation of the Mott cross section is done on a different program and the results are feed to the main program, the Monte Carlo simulator. I hope to put these two program available for download in near future.
My experience with e-beam lithography is based on a Philips SEM515 electron microscopy with a Raith ProxyWriter package to control the beam. Although it has some limitations, it is a perfect instrument to start with a program of e-beam lithography because it presents most of the features of an commercial e-beam system.
Working close with the staff of a microelectronics laboratory has given to me a good understanding of the routines of a clean room: cleaning of the glassware and material, thermal oxidation, thermal evaporation, dry etch processes and optical lithography.
The above mentioned experiences are the most relevants for microelectronics related activities, but before going to microelectronics a 5 year experience in a Physics laboratory as undergraduated and graduated student must be mentioned. I was involved in research of strained superlattices of InGaAs/GaAs and other semiconductors (Si/Ge, SiGe/Si, InGaP,...)and insulators (LiSO4, superionic glasses,...) with optical spectroscopy technics (Raman, Photoluminescense and Photoreflectance).