Nanolithography comprises all lithographic techniques to fabricate nanodevices using top-down techniques. The lab has two different technologies depending on the scale of the dimensions of the device to be manufactured:
Photolithography or optical lithography: microfabrication process based on the transfer of a pattern or design using masks and photosensitive materials in a series of stages that are repeated depending on the complexity of the element to be manufactured. Is applied to the semiconductor and electronics manufacturing technique as sensors, actuators and microelectromechanical systems (MEMS).
Electron Nanolithography: Making structures on the nanometer scale, patterns or designs with at least one dimension from the atomic range around 100 nm. Used in the manufacture of semiconductor integrated circuits and generation of nanoelectromechanical systems (NEMS ).
The “dual beam” equipments are installed in a Class 10.000 Clean Room and they combine focused ion and electron beams with probe sizes down to 1 nm. The ion and electron columns have a common crossover, where the object to be studied or manipulated is placed. Therefore, both electron and ion beams can be focalized in the same area of the sample. In general, the electron beam is used for imaging, whereas the ion beam is used for nanofabrication. In other words, the ion beam has a strong milling capacity and performs the lithography of the object, and the electron beam is used to image the process. Electron lithography can also be done by using electron sensitive resins.
The instrument is equipped with multiple detectors to achieve the desired type of image contrast; in some cases it is interesting to highlight the sample topography, in others the chemical composition changes through the sample, in others the crystallographic orientation, etc. Each dual beam has 5 injectors which can be used to fill the chamber with different gases to assist the lithography processes or the nanodeposition of a material. These nanodeposits can be highly functional, i.e. they can be ferromagnetic (permanent magnetism) or superconducting (extremely low resistance). One of the main applications of the “dual beam” is the preparation of lamellas for transmission electron microscopy (TEM) experiments. For that purpose, it is necessary the ion beam thinning of the area of interest of the material to thickness values below 50 nanometers and put it in a TEM observation grid. This can be done in the dual beam thanks to the combined used of the ion column, the electron column and a nano-manipulator. The scientific and technological applications of these instruments are in the fields of Physics, Chemistry, Biochemistry and Chemical Engineering.