Single-exposure techniques

Pitch-invariant patterning Single-exposure techniques 

Reflow shrink Chemical shrink Plasma-assisted techniques techniques shrink technique 

The single-exposure techniques are based on the lithographic resolution R 

In general, the single-exposure techniques rely on the use of either hyper-NA 1.0 as implemented in immersion lithography (see Chapter 13) or exposure wavelength reduction as implemented in EUV lithography (see Chapter 14) and electron-beam lithography (see Chapter 15). These techniques may be complemented with reticle-based resolution-enhancement techniques such as phase-shifting masks and the like. 

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Fig. 16-14 Photographic method of stress measurement (single-exposure technique). After Norton [16.13].

Fig. 16-15 Stress camera in position for a stress measurement by the single-exposure technique. The head of the x-ray tube is enclosed in a protective cover. (Courtesy of Advanced Metals Research Corporation.)...

Precision is increased by making repeated measurements on each film and averaging the results. Using the single-exposure technique, Norton [16.13] obtained a standard deviation on steel (narrow lines) of 4,5 ksi. 

Pitch-invariant patterning Single-exposure techniques... 

It has only been possible quite recently to obtain preparations of typical high molecular weight substances so uniform that the long identity periods can be observed directly with the x-ray spectrograph. Bernal and Crowfoot have been able to measure identity periods of 67 A and 154 A directly in single crystals of pepsin by using a particularly precise exposure technique a molecular weight of 40000 was obtained with 12 molecules in the elementary cell. A qualitative discussion of intensities allows the conclusion that the protein particles are dense-textured, flattened, spherical clusters with a diameter of about 30 A. ... 

The techniques and technologies of x-ray radiography have most to do with the design of the x-ray tube itself There are many different types of tubes used for special apphcations. The most common is the directional tube, which emits radiation perpendicular to the long axis of the tube in a cone of approximately 40°. Another type is the panoramic tube, which emits x-rays in a complete 360° circle. This type of tube would be used, for example, to examine the girth welds in a jet engine with a single exposure. 

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