Thick-film hybrid microcircuits

Hamer, D. W. Biggers, J. V. Thick Film Hybrid Microcircuit Technology Wiley-Interscience New York, 1972. 

Adhesives may substitute for wire or solder in forming electrical connections for example, in connecting capacitors, resistors, or semiconductor devices to a printed-wiring board or to a thin-film or thick-film hybrid microcircuit. The best and most... 

Of the mass-transfer dispensing methods, screen printing and stencil printing are the oldest and most widely used. Screen printing has been used for over 40 years in the electronics industry to apply thick-film conductors, resistors, and dielectrics in fabricating circuits on ceramic and plastic-laminate substrates. Screen printing is also used as a batch process for depositing electrically conductive and insulative adhesives to interconnect devices on thin-film and thick-film hybrid microcircuits. 

Figure 5.6 Example of a ceramic multichip module (MCM-C) and a hybrid microcircuit. Top MCM-C fabricated from high-temperature cofired ceramic. Source Honeywell Sohd State Electronics Center. Bottom Multilayer thick-film hybrid microcircuit.

Polymer adhesives have found their place in numerous electronics applications. Major uses include eommercial/consumer products computers and military, space, automotive, medical, and wireless communications. Some adhesives may be used aeross several applications while others have been formulated to meet applieation-specific requirements. For example, reworkability is not a consideration for high-production, low-cost consumer products such as cell phones or calculators, but is important for high-value, high-density printed-wiring boards (PWBs) used in military and spaee electronics. Further, thermal stability at high temperatures is required for near-engine electronics in automobiles, aircraft, and for deep-well sensors, but not for office computers. The major applications for polymer adhesives are to attach and electrically insulate or to electrically connect components, devices, connectors, cables, and heat sinks to printed-circuit boards or to thin- or thick-film hybrid microcircuits. In addition, over the last several decades, new uses for adhesives have emerged for optoelectronic (OE) assemblies, microelectromechanical systems (MEMS), and flat-panel displays. 

Thick film (hybrid microcircuits) A conductive or insulating coating prepared by painting,... 

Fig. 4.5 Film devices and circuits (a) thin-film resistors on glass and steatite substrates (b) thick-film resistor networks on snapstrate alumina substrate (c) various thick-film resistors (d) hybrid microcircuits. (Components kindly supplied by General Hybrid, C-MAC and...

In assembling hybrid microcircuits or multichip modules, ceramic interconnect substrates fabricated using thin-film or thick-film processes are attached to the inside base of a ceramic or metal package. Generally, film adhesives that have been cut to size are used to attach large substrates (greater than 1-inch square) while either paste or film adhesives may be used for smaller substrates. Substrates may be alumina, beryllia, aluminum nitride, or silicon. 

Riemer DE. Material selection and design guidelines for migration-resistant thick-film circuits with silver-hearing conductors. In Proc. 31st Electron. Comp. Conf 1981. Licari JJ, Enlow LR. Hybrid Microcircuit Tech. Handbook. 2nd ed. Noyes PubUcations 1998 137-142. 

Screen printing of conductive andinsulative adhesives has been used for decades in the assembly ofhybridmicrocircuit and multichip modules. Since screen-printing processes are also used to deposit thick-film conductors, resistors, and dielectrics, the processes are fully compatible and cost effective in the production of hybrid microcircuits. Screen printing and stencil printing are both batch processes that are usually less expensive and... 

The developments and technological advancements in the area of thick-film resistors have played a major role in establishing thick film as a viable technology. The term thick-film resistor is a generic name applied to a wide variety of resistive materials presently used in hybrid microcircuits and other electronic applications. A thick-fihn resistor is a complex... 

Y Kurakawa, et al. AIN substrates with high thermal conductivity. IEEE Trans Components Hybrids Manuf Technol 8 247 (1985). W Werdecker, F Aldinger. Aluminum nitride—an alternative ceramic substrate for high power applications in Microcircuits. IEEE Trans, Components, Hybrids, Manuf Technol CHMT-7 3394 (1984). N Iwase, et al. Thick film and direct bond copper forming technologies for aluminum nitride substrate. IEEE Trans Comp HEMT-8 253 (1985). N Iwase, et al. Development of a high thermal conductive AIN ceramic substrate technology. Int J Hybrid Microelectron 7 49 (1984). 

There are several non PbASn solders utilized in electronics for specialized applications. One of these, 50Pb-50In, is utilized for hybrid microcircuit applications involving soldering to precious metal (Au-Pd, Au Pt), thick film, and thin film circuits [30]. One advantage of this solder is that its Au thieving (dissolution rate) is much slower than Sn-Pb solders. 

FIG. 23 (a) Hybrid microcircuit (HMC) assembly, (b) A scanning electron micrograph showing the cross section of a thick film solder joint from the HMC. The solder is 37Pb 3Sn and the thick film composition was 76Au-21Pt-3Pd. (Courtesy of Sandia National Laboratories.)... 

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