Shaped electron beam columns

Auger analysis of small features. The primary electron beam column is similar to that in electron microscopes, and it may contain both electrostatic and magnetic lenses for beam focussing as well as quadrupole deflectors for beam steering and octopole lenses for beam shaping. 

As already discussed, there is an important case where resolution is determined by fundamental limitations of the electron optical system and not by electron scattering. This occurs with the high current shaped electron beams used in high throughput direct-write tools. The Coulomb interaction between electrons in these columns displaces the electrons from their intended trajectories and blurs the edges of the spot. As discussed above in connection to throughput, this effect, which is related to the Boersch effect (45) forces a compromise between throughput and resolution. 

With shaped beams the source for the electron optical column is an image of a square aperture that is formed in the plane of a second square... 

The most obvious way to improve throughput in scanning electron beam systems is to combine a variable shaped beam column, with a continuously moving table. The shaped beam ensures maximum beam current, and the continuously moving table potentially eliminates many overhead times. Registration can be accomplished without stopping the table, either by means of a laser interferometer, or through direct beam to sample reference. 

Porous-etching of a (lll)A InP surface in HCI/H2O solution leads to a top layer with a pillar structure characterized by isolated columns stretching perpendicularly to the initial surface [228]. The shape and size of pores can be automatically fixed when porous-etching was combined with conventional electron-beam lithography with an appropriate mask pattern. Triangular pores with fairly good size and uniform and ordered InP triangular vertical pillar structures were obtained [229],... 

Electron Microscopy Electron microscopes are instruments that use a focused beam of electrons to examine objects on a very fine scale. This examination gives information on topography (smface features and texture), morphology (shape and size of particles), composition, and crystallographic data (stmcmral arrangements). In order for the electrons to hit the sample, both the microscope column and sample chamber must be kept under vacuum. 

Real-time measurement of the structural response was achieved by using an electronic data acquisition system. Several instruments were used to monitor the specimen behavior linear variable displacement transducers (LVDTs) to monitor the global deformed shape and the joint panel shear strain a potentiometer on tip beam to monitor the actual displacement imposed by the actuator to the specimen strain gauges on internal steel rebars to record their strains at ends of beam and columns and strain gauges on CFRP quadriaxial sheet along fibre directions to monitor FRP strains at joint panel. 

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