Line-focus-beam technique

The line-focus-beam technique with its associated analysis has been more extensively used than any other method for quantitative acoustic microscopy. 

Anisotropic materials have been extensively measured using the line-focus-beam technique. These will be discussed further in Chapter 11, but some results are summarized in Fig. 8.8 to illustrate the range of materials over... 

More recently, there have been in-process techniques developed. Focused Beam Reflectance Measurement (FBRN ) uses an immersion probe and is capable of in situ measurement of particle chord length. Obscuration measurement can also be used as an in line size measurement. Acoustic size measurement is also emerging as in-process technique that permits use in heavy slurries that are difficult to measure using optical techniques. 

The doped polymer films were modified by laser scanning and simultaneous mechanical sample movement. This technique of polymer modification was recently proposed by our team [14], Chosen polymer area is scanned by continual laser beam line by line. Laser beam was focused into spot with approximate diameter 0.5 pm. Laser operating at 405 nm wavelength and 0.1 W laser power was applied. The laser light of applied wavelength is expected to be absorbed by porphyrine molecules. Sample mechanical movement is added to the laser scanning. The velocity of the sample movement was 2 pm/sec [14]. The process is schematically depicted in Fig. 2. 

Along with the ever increasing demand for on-line or in-line particle characterization in process control, requests for direct measurements of particles in pipelines or reactors are on the rise. In process control, any bias of the characterization method or precise physical meaning of the parameters determined are not of the utmost importance. Robusmess, reliability, and precision of measurement are often the primary concerns. Besides focused beam reflectance and fiber optical PCS probe, back scattering intensity measurement is among the optical techniques preferred for in-process measurement due to the obvious reasons that when the concentration of a suspension is high, the... 

Two newer areas of implantation have been receiving attention and development. Focused ion beams have been iavestigated to adow very fine control of implantation dimensions. The beams are focused to spot sizes down to 10 nm, and are used to create single lines of ion-implanted patterns without needing to create or use a mask. Although this method has many attractive features, it is hampered by the fact that the patterning is sequential rather than simultaneous, and only one wafer rather than many can be processed at any one time. This limits the production appHcations of the technique. 

Newer techniques that are responding to the need for atomic level imaging and chemical analysis include scanning tunneling microscopes (STMs), atomic force microscopes (AFMs) (52), and focused ion beams (FIBs). These are expected to quickly pass from laboratory-scale use to in-line monitoring apphcations for 200-mm wafers (32). 

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