Microelectronics thin-film materials

Indeed these qualities have been developed since the mid-Century so that in a particular segment of the information industry such as telephones and communications, our volume of synthetic polymers used annually exceeds that of any other class of materials, although the actual tonnage of metallic and inorganic matter still leads. For the world of tomorrow, we find microelectronics, thin film circuitry and systems and, especially now photonics, with lasers and light guides, to be dominant components. All of these strongly use polymers, for their special physical-chemical as well as familiar mechanical and electro-optical qualities. 

Chemical and chemical engineering principles involved in plasma-enhanced etching and deposition are reviewed, modeling approaches to describe and predict plasma behavior are indicated, and specific examples of plasma-enhanced etching and deposition of thin-film materials of interest to the fabrication of microelectronic and optical devices are discussed. 

Ruthenium dioxide has been of recent interest for use as a conductive material in microelectronics devices. A range of precursors has been used for the growth of ruthenium-containing thin-film materials, including Ru(tmhd)3, ... 

As a consequence of their superior physical and chemical properties, silicon nitride and silicon carbonitride films have become increasingly important for both structural and microelectronic device applications. Chemical vapor depositions (CAH)) has become a major technique for the synthesis of these thin film materials flO]. 

The industrial use of plasma processing has been developed mainly by the microelectronics industry since the late 1960s, for the deposition of thin film materials and plasma etching of semiconductors, metals, and polymers such as organic photoresist. The third type of plasma process for surface modification is currently used in areas other than microelectronics, namely in aerospace, automotive, biomaterials, and packaging, to name only a few examples. The potential for obtaining unique surface modifications by plasma treatment is widely recognized [7]. 

Metallic electrical conductor films are widely used in the hybrid microelectronics and semiconductor industry, where thin film blanket metallization, which covers the whole surface, is chemically etched or plasma etched into conductor patterns. The thin film material can also be deposited through a physical mask to form a conductor pattern on the surface. Masking techniques are useful on conductor geometries down to about 2-5 microns in width and have the advantage that they do not have to be chemically etched. 

At the start of this Chapter, an essay by Peter Day was quoted in which he lauds the use of soft chemistry , exemplifying this by citing the use of organometallic precursors for making thin films of various materials used in microelectronics. The same approach, but without the softness, is increasingly used to make ceramic fibres here, ceramic includes carbon (sometimes regarded as almost an independent state of matter because it is found in so many forms). 

E. S. Machlin, Materials Science in Microelectronics—the Relationships between Thin Film Processing and Structure. Giro Press. Croton-on-Hudson, NY, 1995. 

In the field of microelectronics, there is continuing research in developing new materials to be used in semiconductor fabrication. They must be formed as thin films in a controlled, reproducible and uniform manner to be useful in semiconductor manufacturing applications. Depth profiling by AES is used to assess the properties of such films. The samples are sputtered with an argon ion beam and analysis performed using standard sensitivity factors, and it is possible to demonstrate that such films are uniform throughout a depth of, say, 250 nm. 

Poly(naphthalene) is chemically similar to poly(p-phenylene), which is an insoluble, infusible, low-molecular-weight polymer, all attributes that preclude application in thin-film form in microelectronics. Although these materials possess several very desirable properties, such as high glass transition tempera-... 

The rapid developments in the microelectronics industry over the last three decades have motivated extensive studies in thin-film semiconductor materials and their implementation in electronic and optoelectronic devices. Semiconductor devices are made by depositing thin single-crystal layers of semiconductor material on the surface of single-crystal substrates. For instance, a common method of manufacturing an MOS (metal-oxide semiconductor) transistor involves the steps of forming a silicon nitride film on a central portion of a P-type silicon substrate. When the film and substrate lattice parameters differ by more than a trivial amount (1 to 2%), the mismatch can be accommodated by elastic strain in the layer as it grows. This is the basis of strained layer heteroepitaxy. 

Surface tension and contact angle phenomena play a major role in many practical things in life. Whether a liquid will spread on a surface or will break up into small droplets depends on the above properties of interfaces and determines well-known operations such as detergency and coating processes and others that are, perhaps, not so well known, for example, preparation of thin films for resist lithography in microelectronic applications. The challenge for the colloid scientist is to relate the macroscopic effects to the interfacial properties of the materials involved and to learn how to manipulate the latter to achieve the desired effects. Vignette VI provides an example. 

The basic research in the future should be oriented towards novel materials for use in carbon dioxide as a solvent. These materials may have important applications in the synthesis of polymers, pharmaceuticals and other commodity chemicals, in the formation of thin films and foams, in coatings and extracts, and in the manufacture of microelectronic circuits. The full deployment of these applications would result in significant reductions in both volatile emissions and aqueous- and organic liquid wastes in manufacturing operations. 

Donor adducts of aluminum and gallium trihydride were the subject of considerable interest in the late 1960s and early 1970s.1 Thin-film deposition and microelectronic device fabrication has been the driving force for the recent resurgence of synthetic and theoretical interest in these adducts of alane and gallane.24 This is directly attributable to their utility as low-temperature, relatively stable precursors for both conventional and laser-assisted CVD,59 and has resulted in the commercial availability of at least one adduct of alane. The absence of direct metal-carbon bonds in adducts of metal hydrides can minimize the formation of deleterious carbonaceous material during applications of CVD techniques, in contrast to some metal alkyl species.10, 11... 

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