Manufacturing thin films

Most experts consider tlnn-film technology to be the future of the PV industiy because of the reduced material rec uirements, the reduced energy required to manufacture thin film devices, and the ability to manufacture thin films on a mass-production basis. 

Aluminum metallization in combination with tantalum thin films is used for manufacturing thin-film capacitors built into the metallization pattern.340... 

R. A. Powell and S. M. Rossnagel, PVD for microelectronics, sputter deposition applied to semiconductor manufacturing Thin Films, Vol. 26, Academic Press, New York, 1999. 

PrintPack, Inc. manufactures thin films for use in barrier applications. We used PrintPack EX429-325 coextruded film with the following layer distribution 1.8 mil LDPE // 0.3 mil tie // 0.3 mil EvOH - 32 // 0.3 mil tie //0.8 mil polycarbonate. The tie layer was Plexar 3342 from Quantum Chemical (The chemical composition of this tie layer material is proprietary and has not been disclosed by the manufacturer). 

Electron Beam Deoositlon- this technique uses an electron beam instead of an ion beam. In this respect, it is not as versatile as the ion-beam method or other methods used to manufacture thin films. 

Viscous Liquids. Fluids with viscosities up to 50.000 centipoise can be processed in a standard thin-layer evaporator. "Zero-clearance" rotors do not exhibit the range of viscosity application that "fixed-clearance" rotors exhibit. Some firms manufacture "thin-film" vertical extruders" for the 50,000 to 20,000,000 centipoise range where fluids cease to flow under the influence of gravity alone. Thin-film evaporators, inherently low-pressure-drop devices, have mechanical turbulence and therefore relatively good heat transfer properties over a wide range of viscosities. 

Molybdenum hexafluoride is used in the manufacture of thin films (qv) for large-scale integrated circuits (qv) commonly known as LSIC systems (3,4), in the manufacture of metallised ceramics (see MetaL-MATRIX COMPOSITES) (5), and chemical vapor deposition of molybdenum and molybdenum—tungsten alloys (see Molybdenumand molybdenum alloys) (6,7). The latter process involves the reduction of gaseous metal fluorides by hydrogen at elevated temperatures to produce metals or their alloys such as molybdenum—tungsten, molybdenum—tungsten—rhenium, or molybdenum—rhenium alloys. 

As with ah thin-film PV technologies, the projected manufacturing costs of a-Si H ahoy PV modules fah rapidly with annual manufacturing volume, ie, MWp /yr. The primary driver of this volume cost reduction is the volume—cost relationship of commercially available thin-film processing equipment. Thin-film coating machines often have capacities equivalent to 3—5 yr, so that manufacturing economies of scale are more fully realized at the... 

Small-area thin-film CdTe solar cells have been fabricated with sunlight-to-electricity conversion efficiencies near 16%, comparable to crystalline siUcon solar cells in large-scale manufacturing. Large-area monolithic integrated CdTe modules have been fabricated with efficiencies of ca 10%, comparable to crystalline siUcon modules commercially available. 

In another method of tempering, soHd chocolate shavings are added as seed crystals to Hquid chocolate at 32—33°C. This is a particularly good technique for a small confectionery manufacturer, who does not produce his own chocolate. However, the shavings are sometimes difficult to disperse and may cause lumps in the finished product (20). Most companies use continuous thin-film heat exchangers for the tempering process. 

Dry gas seals are in the positive seal class and have the same basic design features as mechanical face seals with one significant difference. The dry gas seal has shallow grooves cut in the rotating seal face located part way across the face. The grooves may be in a spiral pattern the exact location and pattern vary from one manufacturer to another. Lubrication and separation is effected by a microscopically thin film of gas. This implies some finite amount of leakage, which is quite small but must be accounted for in the design. 

Another common device used in the rubber industry is the thin film evaporator. This device is very often used in the manufacture of ultra-low molecular weight elastomers that are used in sealant applications or specialty coatings, and as processing aids in conventional rubber compounding processes. The thin film evaporator described earlier, has found a multitude of other industry applications, including food processing operations. 

Applications Although a wide range of metals can be sputtered, the method is often commercially restricted by the low rate of deposition. Applications include the coating of insulating surfaces, e.g. of crystal vibrators, to render them electrically conducting, and the manufacture of some selenium rectifiers. The micro-electronics industry now makes considerable use of sputtering in the production of thin-film resistors and capacitors . ... 

Optoelectronics is a relatively new and fast-growing industry with many applications. Thin-film processes, such as reactive sputtering, molecular-beam epitaxy (MBE), and particularly MOCVD, play a major part in their production. Equipment and materials are similar to those used in the semiconductor industry and many companies manufacture both types of products. In fact the distinction between the two areas is often blurred. Statistics generally do not single out optoelectronics as such and, for that reason, it is difficult to define the scope of the industry accurately. 

The U.S. electronics industry appears to be ahead of, or on a par with, Japanese industry in most areas of current techniques for the deposition and processing of thin films—chemical vapor deposition (CVD), MOCVD, and MBE. There are differences in some areas, thongh, that may be cracial to future technologies. For example, the Japanese effort in low-pressure microwave plasma research is impressive and surpasses the U.S. effort in some respects. The Japanese are ahead of their U.S. counterparts in the design and manufacture of deposition equipment as well. 

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