The influence of substrate compliance

The film thicknesses at which many strained epitaxial thin film materials begin to degrade in quality due to dislocation formation are too small to permit their use in electronic device development. For very thick substrates of the kind assumed in preceding sections in this chapter, any lattice mismatch between the film and the substrate must be accommodated by deformation of the film. This situation can be alleviated to some degree if the thickness of the substrate is of the same order of magnitude as the thickness of the film deposited on it. In this case, accommodation of a mismatch in lattice parameter can be shared between the film and substrate materials, thereby 

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It is important to examine the influence of impurities or additives, such as sizes and lubricants, since these are often prime sources of higher AOX values rather than the substrate itself. It is equally important to assess the contribution of auxiliaries in the bleaching bath to the total AOX value. Kleber [224] has reported several studies of systems requiring compliance with an AOX consent of 3 ppm. Table 10.20 shows that (a) synthetic... 

Numerous geometrical factors of the specific interconnection will also influence anisotropic adhesive formulation and processing, including lead planarity, IC pad metallization, and IC test patterns. The planarity of the leads on the substrate and/or device and the compliance of the conductive particles will determine if anisotropically conductive adhesives can be used in a particular application. For systems with large disparities between lead height, no electrical interconnection will be formed, as shown in Fig. 5. Fine-pitch IC packages for surface-mounted applications, such as the plastic quad flat pack (PQFP), often use gullwing leads that olfer much compliance to the joint. Even if the... 

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