7.2.2 Bio-Molecules

AFM images of bio-molecules such as DNA are easily measured as long as the bio-molecules are directly attached to a surface. Activated substrates are available for creating DNA images with an AFM. There are many examples of AFM DNA images as well as many images of other types of bio-molecules such as proteins. The AFM is capable of systematically removing genetic material from DNA or chromosomes by scratching the surface of the material.

FIGURE 7-12 DNA image 1.2u x 1.2u.

7.3 High Technology

The high technology industries, including semiconductors, data storage and advanced optical devices, use AFM for product/process development and in some cases for process control. Many of these industries already rely on manufacturing procedures that create structures with nanometer sized dimensions.

7.3.1 Semiconductor

There are numerous applications for the AFM in the semiconductor industry both in the front and back end. The AFM has played a critical role in the development of many semiconductor processes such as CMP in the mid 1990's. The greatest limitation for the AFM in applications for the semiconductor industry is the availability of reliable probes with nanometer scale dimensions. Advanced applications include: electrical testing, etch verification, and secondary defect review.

Because of probe geometry, not all dimensions of device structures are measurable with an AFM. In Figure 7-13, dimensions that are measurable include: