Biomedical Engineering Reference
In-Depth Information
topography of human hair, and in addition can make quantitative measurements of hair
surface roughness and frictional properties [726, 727]. AFM can be applied to image the
effects of many different cosmetic products on hair, for instance, the effect on topography
and friction of hair bleaching [728], or the effects of shampooing and conditioning with
different products can be studied [729].
7.4.2 High-technology applications
High-technology companies produce high profit-margin products that usually use advanced
manufacturing technologies. These types of companies commonly adopt new techniques
such as AFM to facilitate their research efforts, and less often, may use AFM to support
production when necessary. The digital data storage industry and the semiconductor
industries rely on AFM for solving some of their most difficult problems. Other products
that have used AFM for product development include flat panel displays, optics, micro-
electromechanical systems (MEMS), and biosensors.
High-technology industries require novel materials, devices and processing cap-
abilities. In a commodity-based company product development is 5% of revenue
whereas high-technology companies spend 10-15% of their revenue on product
development. Thus high-technology companies can afford to invest in atomic force
microscopes.
Such industries often require high dimensional tolerance. Further, high-technology
companies need to have an understanding of fundamental material behaviour in order to
improve performance, manage quality control, and to improve product yields. An atomic
force microscope is one of several tools available to high-tech companies which are
capable of making such measurements. It should be noted though, that the AFM is a
relatively new tool and typically other microscopes, such as electron microscopes, are
used before an AFM for applications in technology industries.
Another characteristic of technology companies is that they often have to improve
and change their processes in a very short time period when compared to traditional
commodity-based companies. Thus, a company may need to use an AFM to support a
manufacturing process for only a few years, after which the company may not need the
microscope.
The limiting issues for broad acceptance of atomic force microscopes in the high-
technology industries are probably probe quality and image capture rates. Variations in
AFM probe geometries result in unwanted variations in quantitative measurements.
Additionally, if a probe is damaged while scanning a surface, it is difficult for an operator
to know, and erroneous data may be collected. When compared to optical and electron
beam techniques, the AFM is sometimes considered to be slow. Thus, the AFM is used
only for product development and off-line production applications.
Specialized AFM products are often required for high-technology industries. For
example, in the semiconductor industry, the AFM must be particulate free so that it does
not contaminate product wafers. Also, sample sizes can be very large in the high-technology
industries. In order to design an AFM that can handle large sheets of glass for the LCD
industry, the final instrument must be very large and heavy. It is not uncommon for these
AFM instruments to weigh several thousand pounds. For many applications the AFM must
be able to automatically measure several images on the same sample.
