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Intl. Journal of Microcircuits and Electronic Packaging Multilayer Cofired RCs for Line Termination Andrew Ritter, Maureen Strawhorne*, Benjamin Smith, Allen Templeton**, Robert Heistand II AVX Advanced Product and Technology Center 2200 AVX Drive Myrtle Beach, South Carolina 29577 Phone: 843-946-0660 Fax: 843-626-9632 e-mail: [email protected] * AVX Limited Hillman’s Way Coleraine, Northern Ireland. BT52 2DA Phone: 01265-40475 **Philips Components 6071 St. Andrews Rd Columbia, South Carolina 29212 Phone: 803-772-2500 Abstract The use of a cofired resistor-dielectric material system allows design and fabrication of fully integrated series resistor- capacitor devices that can be made very small due to high volumetric efficiency. These devices employ resistive electrodes and can be produced using a modification of high volume multilayer capacitor manufacturing and thus can meet the need of digital circuit designers for low cost integrated components in high speed circuits. The design of the cofired device does not permit testing of the individual component values; therefore, high frequency test methods are used to allow series capacitance and resistance to be determined from impedance data. Key words: Integrated Passive Device, Cofired Resistor, Line Termination, Series RC, Impedance Chip, Surface Mount Device, and SMD. 1. Introduction Digital circuits in consumer electronics are being developed to achieve unprecedented clock speeds along with reductions in size and power consumption — yet at constant, or even lower, selling price! These higher performance systems use increasingly greater numbers of passive components. For example, one can count almost 1500 passive components on a Pentium II® 333 MHz motherboard compared to approximately 165 passives on a “stateof-the-art” 486 processor of 1994 vintage1 (Table 1). This figure is nearly an order of magnitude increase over just several generations of processors, and this trend is predicted to continue unabated2. Passive component suppliers are responding to this need with new approaches to miniaturize and reduce cost. Recent developments include non-noble metal electrodes, improved volumetric efficiency through material and process improvements, and component arrays that save space and assembly costs. One area that has been relatively under-exploited is integration of multifunction passives within the same package. This paper addresses integration of resistors and capacitors in series (that is, series RCs) that have primary application for AC bus termination of data transmission lines. These terminators are used to maintain signal integrity by controlling signal reflections, adjust The International Journal of Microcircuits and Electronic Packaging, Volume 21, Number 4, Fourth Quarter 1998 (ISSN 1063-1674) 334 8 International Microelectronics And Packaging Society Multilayer Cofired RCs for Line Termination propagation delays, and minimize power consumption. A series RC device has an impedance (|Z|) characteristic (Figure 1) that is dominated at “low” frequency by the capacitor (|Z|~1/(2o *frequency*Cs) and at “high” frequency by the resistor (|Z|~Rs). The corner frequency is where the phase is -45° and the formal transition from series capacitive (Cs) to series resistive (Rs) behavior occurs. Table 1. Passive component evolution on PC motherboards. 486 Leaded MLC SMD MLC Cap Arrays (x4) Leaded Res SMD Res Res Arrays (x2,4) Other Total 58 0 0 92 0 0 15 165 Pentium™ 120 MHZ 0 151 0 0 146 64 8 369 Pentium™ 200 MMX 0 190 32 0 188 148 35 593 Pentium II™ 333 MHZ 0 300 140 0 635 346 52 1473 consumption just to pulse switching and provide a small phase delay for tailoring timing circuits. The selection of specific resistance and capacitance values with respect to circuit design is largely application driven3,4. A series R-C termination can be achieved most simply by placing two discrete components, one resistor and one capacitor in 0603 or 0402 case sizes, adjacent to one another on the circuit board. [Note: Electronics Industry Association (EIA) standard case size nomenclature denotes length and width in mils, for example, an “0603” part is nominally 0.060"x0.030" (1.54 mm x 0.77 mm)]. By using discrete chips, system designers have greatest latitude in independently selecting component values and can respond quickly to eleventh-hour changes to tune circuit performance. In cases of multiple data lines, board space can be saved using resistor and capacitor arrays, typically in sets of 4 or more elements. Component arrays also have benefit to reduce the overall passive component count on the board and therefore lower the overall component board-mounting costs that in many cases are significantly higher than the cost of the passive component itself2! Additional space saving and component count reduction can be achieved when the capacitor and resistor elements are integrated into the same package. Component manufacturers have employed a number of approaches for this integration. The most straightforward approach (Figure 2A) is fabrication of an integrated device by screen printing single-layer resistor and capacitor elements onto an inert substrate, with separate firing steps between application of each material (conductor, dielectric, conductor, resistor, and overglaze). R R C C a) single-layer hybrid b) resistor on capacitor Figure 2. Methods of integration for thick film RC devices include a) single layer elements on an inert substrate and b) single layer resistors printed on prefired multilayer capacitors. Figure 1. The impedance of a series RD device, as compared to a multilayer capacitor, is dominated by capacitive behavior at low frequency and resistive behavior at high frequency. The corner frequency is marked with a dot. 2. Hybrid Integrated RC Designs In a substrate structure, the volumetric efficiency is relatively low since most of the device is electrically inactive and the capacitors are limited to a single layer structure. A design variant, using a multilayer capacitor itself as the substrate (Figure 2B), improves volumetric efficiency. This approach also benefits from a wider range of capacitance values that can be used in designing the device. However, it includes a complication from the need to incorporate a via to make the series resistance connection and, more importantly, requires printing conductors, resistors, and overglaze onto very small (0805 and 1206) components. The concept for the devices discussed in the rest of this paper arose from a desire to drastically change the construction of integrated R-C components. Ideally, this change would eliminate many of the inactive portions of the device and reduce the number of manufacturing steps, which would in turn allow for miniaturization and improved volumetric efficiency while reducing overall costs. In bus termination applications, the resistance value is selected to match the characteristic impedance of the line trace on the board to prevent ringing,Journal and theofcapacitor servesand to both limit power The International Microcircuits Electronic Packaging, Volume 21, Number 4, Fourth Quarter 1998 (ISSN 1063-1674) 8 International Microelectronics And Packaging Society 335 Intl. Journal of Microcircuits and Electronic Packaging 3. Fully Integrated Cofired RCs Cofirable material systems are comprised of dielectrics, resistors, and conductors that are optimized to densify at similar firing temperatures with nearly matched shrinkage and minimal chemical interaction. These material systems allow the design of multilayer devices wherein the capacitor and resistor elements are fully integrated in the structure of the device. Unlike ceramic chip-carrier packages with single-layer buried resistors interconnected with buried metallic conductors — currently the most common usage of these cofirable material systems — the fully integrated RC is made with a stack of multiple, closely spaced resistor elements arranged in a multilayer capacitor structure (Figure 3). subdivision, and then solves the resulting electrical network in the Frequency Domain. Comparison of measured and simulated behavior (Figure 4) of a 47 pF-100 W cofired RC shows the characteristic impedance of the integral resistor electrode series capacitor device. To first approximation, the device behavior is equivalent to a simple series RC. However, there is a predicted and measured minor drop of the high frequency |Z| due to the distributed R-C components. Above the corner frequency, the device impedance is found to decrease by approximately 3-5%/decade, rather than being flat as found with conventional series resistor-capacitor circuits made with discrete components. Resistive electrodes Figure 3. A cofired seried RC can be fabricated by making resistive electrodes in a structure similar to multilayer capacitors. Alternate layers have parallel termination. The device capacitance arises from dielectric between the planar resistor elements that are alternately terminated in the multiFigure 4. Measured and modeled impedance of an integral layer capacitor structure. In this structure, the resistor layers themelectrode cofired RC device shows the general behavior of a selves form the electrodes of a parallel plate capacitor. The sets of simple series RC circuit. resistive electrodes that form a single capacitor element also create one of the parallel elements of the total device resistance. It is The cofired dielectrics used in the current generation of devices important to note that each effective resistor layer is made of two, are combinations of glasses and metal oxides. In conventional or three, discontinuous segments that are capacitively coupled. The cofired chip carrier packages made using commercially available authors have coined the term |Z| Chip™ (patent pending) for this LTCC (low temperature cofired ceramic) materials, typical fired device to denote its application for impedance matching. Although dielectric thickness is 80-100 µm. However, for the multilayer the cross-section of this cofired RC is simple, the device is electricofired RC, the typical dielectric thickness can be as low as 10-15 cally complex since the capacitance and resistance are physically µm, almost an order of magnitude less. The reduced thickness of distributed throughout the entire device. the dielectric layer greatly improves volumetric efficiency and alA partial element equivalent circuit method has been used to lows fabrication of small devices with very stable, low permittivity model the device5. This distributed network model uses the physimaterials, with a temperature coefficient of capacitance of ~250 cal dimensions of an actual part, that is, individual layer cross secppm/°C from -55° to +125°C. Despite relatively thin dielectric tion, their thickness and number, and material constants such as layers, device withstanding voltages is well over 500 volts (typidielectric permittivity, and ink resistivity to simulate current flow cally 75-100V/µm) and insulation resistance is greater than 1000 within the device. The model partitions the component geometry, GW for the cofired multilayer components. computes partial capacitances, resistances, and inductances for each The International Journal of Microcircuits and Electronic Packaging, Volume 21, Number 4, Fourth Quarter 1998 (ISSN 1063-1674) 336 8 International Microelectronics And Packaging Society Multilayer Cofired RCs for Line Termination The resistor elements in the cofired RC are also a combination of glass and metal oxides, principally RuO2, used to achieve resistance values common for AC termination applications with a measured temperature coefficient of resistance of ±250 ppm/°C. An important feature of this cofired RC architecture is that the internal device electrodes are ceramic rather than metallic, as with a conventional multilayer capacitor, and thus form an integral structure with the dielectric after firing (Figure 5). This structure significantly minimizes the thermal expansion mismatch common to all conventional multilayer electronic components with buried metallic electrodes. The mismatch between the metal electrode and the ceramic dielectric is one of the driving mechanisms for thermal shock failures and is a source for long term reliability concerns in traditional multilayer components. Ceramic electrode cofired RC devices survive at least 1000 hours of testing at 85°C, 85% relative humidity at twice rated voltage after having experienced thermal shock wave solder (that is, no preheat) and 100 rapid temperature cycles between -55° and +125°C (Table 2). Since the internal resistor is capacitively coupled, that part of the device cannot be stressed with dc current as may be done for lifetesting conventional chip resistors. Traditional lifetest methods for multilayer capacitors rely almost exclusively on static voltage to accelerate potential degradation mechanisms. In order to increase stress on the resistive part of the cofired RC, a pulsed voltage test has been used. This test applies voltage pulses at 12.5 mW (1/10th rated power) at a 1 Hz rate while parts are soaking at 85°C and 85% relative humidity after undergoing thermal shock-thermal cycle testing. As with the more conventional multilayer-type lifetests, the cofired RCs pass at least 1000 hours of pulsed 85/85 testing, indicating long-term stability of the cofired resistor structure. ELECTRODE a) multilayer capacitor 10 µm b) multilayer RC Figure 5. Unlike conventional multilayer capacitors (a), cofired multilayer RCs (b) have shrinkage-matched ceramic electrodes that simplify processing and improve reliability. Parameter Solderability Leach Resistance Thermal Shock Thermal Cycle Dry Life Temp-Humid-Bias (THB) Pulsed THB Voltage Breakdown PCB Flexure Mean Shear Strength Porosity Test Condition* 5 sec @ 235°, >95% coverage 30 sec @ 260° w/ preheat, >75% coverage 260°C wave solder, no preheat 100 cycles, -55° to +125°C 1000 hrs @ 125°C, 50V 1000 hrs @85%RH, 85°C, 50V 1000 hrs @85%RH, 85°C, 125mW @ 1Hz 22°C, 100V/sec ramp long axis, 90mm span, 1mm/sec rate perpendicular to termination SEM 47pF/100Ω 0/10 0/10 100pF/47Ω 0/10 0/10 0/240 0/100 1/200** 0/100 0/100 0/240 0/100 0/200 0/100 0/100 604V > 5 mm 2.1 kg 1.2% 575V > 5 mm 2.2 kg 1.1% A further benefit of the multilayer resistor structure in the cofired device allows power dissipation throughout the entire part volume, rather than confining current flow to a single layer as with hybrid RCs although in this instance, the ceramic electrodes are not as efficient in conducting heat out of the device. Nonetheless, measured power handling capability approaches 250mW for 0603 discrete cofired RCs, measured by applying a 20 MHz ac-voltage to board-mounted chips and monitoring temperature increase from 70° to 125°C as the signal amplitude (power) was increased. 4. Cofired RC Testing and Electrical Performance Since the resistor and capacitor elements are fully integrated in the cofired series RC, the device resistance cannot be measured independently, but must be extracted from the device impedance characteristic. In a practical sense, determination of series resistance and capacitance must be made in a regime where the device properties are in transition from capacitor to resistor, that is, where the phase is changing from -90° (capacitive) to 0° (resistive). Figure 6 shows measured series resistance and capacitance relative to phase for a cofired RC. For AC line termination applications, relevant series resistance and capacitance measurements must be made at frequencies between 1 and ~500 MHz, where electrical properties are nearly constant, and also in the frequency regime where the AC terminators are used. Below 1 MHz, the measured series resistance is dominated by the frequency-dependent dielectric loss of the capacitor, and measurements are not valid for the bus terminator. Above several hundred MHz, the device has a capacitive resonance and thus series capacitance measurements are not accurate. Impedance measurements on the cofired device with a Network Analyzer (Figure 7) show nearly ideal RC behavior almost to 10 GHz, at which point inductive effects begin to dominate. Table 2. Qualification test summary for 0603 cofired RC. The International Journal of Microcircuits and Electronic Packaging, Volume 21, Number 4, Fourth Quarter 1998 (ISSN 1063-1674) 8 International Microelectronics And Packaging Society 337 Intl. Journal of Microcircuits and Electronic Packaging Figure 6. Rs versus frequency for a 150pF-33W cofired RC shows that measurements above 1 MHz avoid effects from the integral capacitor. Figure 8. Ringing in 80 MHz clock pulses is virtually eliminated when the transmission line is terminated with a cofired multilayer RC (the bold line is the terminated trace). 5. Cofired RC Development Trends Passive electronic component suppliers and consumers use the spacial density of components on a printed circuit board as a metric for integrated devices2. The localized component density is determined by dividing the number of functional components within a device by the area of circuit board required to mount the device, that is, the length by width of the part, including a 0.5 mm margin on all sides for solder pads and nearest neighbor spacing (Figure 9). Calculated local component densities for a variety of discrete and integrated devices, (Table 3), show the benefit of the volumetric efficiency cofired multilayer RC. 0603 Figure 7. Impedance versus frequency, measured with a network analyzer, shows nearly ideal behavior for the distributed RC device up to 10GHz. 1206 0805 0603 0603 78% 50% 0402 34% 114% Electrical characteristics of integrated passive devices must equal or better the performance of the discrete parts they replace or there will not be wide market acceptance. The most crucial electrical test for any component is to measure performance of the device in a circuit approximating a customer’s application (Figure 8). A circuit was constructed with an 80 MHz oscillator driving a 47 W transmission line with test points to allow the integrity of the clock pulses to be monitored. Without proper termination, the pulses show ringing and overshoot at levels ~50% of the average pulse height. Addition of a 100 pF, 47 W cofired RC terminator to the line shows that signal integrity is restored. Even though the device is constructed with a distributed resistor-capacitor design, it performs as a simple discrete RC solution. Discrete RC Benchmark Figure 9. Board-level device area, including 0.5mm standoff spacing, for single pair integrated RCs can be compared with the a standard discrete RC circuit made with 0603 “benchmark” devices. Table 3. Discrete and integrated passive device board-level component density. The International Journal of Microcircuits and Electronic Packaging, Volume 21, Number 4, Fourth Quarter 1998 (ISSN 1063-1674) 338 8 International Microelectronics And Packaging Society Multilayer Cofired RCs for Line Termination Component Board Area (cm2) No. of Elements 1206 Discrete 0805 Discrete 0603 Discrete 0402 Discrete 0201 Discrete 1206 RC Discrete 0805 RC Discrete 0603 RC Discrete 0402 RC Discrete 1206 Cap Array 0805 Cap Array 0603 Cap Array 2512 RC Network 1608 RC Network 1206 RC Network 0805 RC Network 0603 RC Network 0.103 0.070 0.045 0.031 0.019 0.103 0.070 0.045 0.031 0.103 0.070 0.045 0.299 0.155 0.103 0.070 0.045 1 1 1 1 1 2 2 2 2 4 4 4 8 8 8 8 8 Component Density (elements/cm2 ) 10 14 22 32 53 19 29 44 65 39 57 89 27 52 78 114 178 Assem. Ops. per 100 elements Figure of Merit (Comp. Den. / Assem. Ops) re:// 0603 100 100 100 100 100 50 50 50 50 25 25 25 13 13 13 13 13 0.5 0.6 1 1.5 2.4 1.7 2.6 4.0 5.9 7.1 10.4 16.2 9.8 18.9 28.2 41.4 64.5 RCs with four series RC pairs in 1206 sizes have a local board density of 78 elements/cm2, compared to a density of 22 elements/ cm2 for the 0603 discrete “benchmark”. With continued development, the 1206 devices will evolve to 0805s (at least) and board densities will increase to 114 elements/cm2 and higher. This realization exceeds the NEMI target for board densities for hand-held electronics. Anticipated increases in the internal complexity of the device, drawing in part on the strategy of integral resistor-capacitor structure, will further increase the local component density by increasing the number of integrated functions within a given case size. 6. Summary Using discrete 0603 chips, board designers can create series RC circuits that have a local maximum component density of 22 elements/cm2 on the printed circuit board. For simple integrated RC Unique series RC devices for impedance matching data transdevices made with single- layer thick film hybrid materials on alumission lines have been developed with cofired buried resistormina substrates, which are currently produced in 1206 case sizes, dielectric material systems. These components are not simply a the component density is 19 elements/cm2. For an 0603 cofired hybrid of two types of passive components on a single piece of multilayer RC, the component density is 44 elements/cm2. Inteceramic substrate, but instead actually integrate two electronic comgrated chips in the “large” case size do not offer a significant board ponent functions into the same physical structure. This component space savings, but the integrated devices reduce by half both the is therefore an integrated passive device in the true sense of the number of solder joints (such as, improved reliability) and the numword. The structure is realized by making multilayer resistor eleber of chip assembly operations in board fabrication. For a cofired ments in a multilayer capacitor geometry, giving benefits of high 0603 integrated “discrete” RC (for example, a single RC pair), there volumetric efficiency, distributed power handling, and greatly simare not only benefits of fewer external connections and placement plified assembly compared to other approaches for making series operations, but also a 50% board “real estate” savings. As shown RC components. Multilayer resistive electrode series RCs have in Table 3, the authors propose a Figure of Merit that gives a single been made with resistance values as low as 10 ohms, and capacivalue that incorporates factors for solder connections, pick-andtance as high as 220 pF, in a standard EIA 0603 case size. The place operations, and local component density. The Figure of Merit cofired RC components have the robust reliability performance of is calculated by dividing the board-level component density by the a conventional thick film device like a multilayer ceramic capacinumber of pick-and-place assembly operations per 100 chips, nortor, plus an additional benefit of ceramic, rather than metallic, “elecmalized to the 0603 discrete component, the current benchmark trodes” that virtually eliminates thermal expansion mismatch ischip size for discrete resistor-capacitor combinations used for line sues that affect long-term reliability. termination in the computer industry in 19982. With additional The novelty of this fabrication method becomes apparent when development, cofired single RC pairs will be produced in an 0402 considering that a 2-element “discrete” |Z| Chip™ device can be case size, with a component density of 65 elements/cm2, making made in an 0603, or even 0402, case size (Figure 10), much smaller even greater board space savings possible. than can be achieved with currently available hybrid integrated RC Hand-held electronics, such as cellular telephones and pagers, devices that require formation of distinct single layer capacitors have some of the most stringent component size restraints in the and resistors in the component package. Furthermore, just as disindustry and the pressures for low cost miniaturization are very crete thick film multilayer capacitors can be fabricated as multistrong. In these types of devices, local maximum component denelement arrays to allow better use of circuit board space, cofired sities are expected to remain constant at approximately 100 eleRC devices have been made as multi-element series RCs in 1206 ments/cm2 over the next decade2. These types of component densicase sizes (|Z| Array™) that exhibit even higher volumetric effities cannot be achieved with discrete components or simple inteciency than the discrete devices. A Figure of Merit, based on the grated RCs. In NEMI parlance, an array of multilayer cofired RCs component density divided by the number of pick-and-place opis a component network, that is, an array of different-function comerations per the number of integrated elements, allows easier components within a single package. Thus, the cofired thick film RC parison of discrete and integrated devices. network is a direct evolution of thick film single-function passive component arrays. Just as the thick film capacitor and resistor arrays were developed for improved volumetric efficiency compared to discrete capacitors, RC networks have the highest component densities (Table 3) and the cofired devices with integral electrodes can be made smaller than other thick film integrated devices. Cofired The International Journal of Microcircuits and Electronic Packaging, Volume 21, Number 4, Fourth Quarter 1998 (ISSN 1063-1674) 8 International Microelectronics And Packaging Society 339 Intl. Journal of Microcircuits and Electronic Packaging Loaded Net,” EDN, May 1996. 5. B. Beker, G. Cokkinides, and A.Templeton, “Analysis of Microwave Capacitors and IC Packages,” IEEE Transactions on Microwave Theory and Techniques, Vol. 42, No. 9, pp. 17591764, September 1994. About the authors Figure 10. Cofired integrated passive devices have been fabricated as discrete 0603’s and 0402’s, and 0612 eightelement networks to achieve component densities up to 78 elements/cm2. The trends for miniaturization and cost reduction in the consumer electronics industry are legendary. These market drivers are unrelenting and challenge the creativity of component manufacturers. The large volumetric efficiency of cofired RCs provides one solution that places passive component suppliers ahead of current NEMI component density targets. Through continual improvements, such as, smaller case sizes and increased electrical complexities, they can remain in a position to anticipate customer requirements rather than react to them. For circuit designers faced with requirements to “do more with less,” the integrated cofired RC approach means further miniaturization and space savings on circuit boards. This will allow them to avoid succumbing to the trend for explosive growth in passive component counts as more sophisticated digital circuits evolve. For designers of passive components, the cofired RC approach offers an enormous variety of new integration options to pack increased functionality into new products. References 1. Robert Heistand II, “Solutions for Passive Integrations,” Proceedings of IMAPS Third Advanced Technology Workshop on Integrated Passives Technology, Denver, Colorado, April 1998. 2. “National Electronics Manufacturers Technology Roadmaps — December, 1998,” National Electronics Manufacturers Initiative, Inc., 2214 Rock Hill Road, Herndon, Virginia 220704005, 1998. 3. “Transmission Line Effects in PCB Applications,” Motorola Application Notes, AN-1051, 1990. 4. Mai Vu, “Signal Reflection and Pedestal Effect of a Heavily Mr. Ritter has been with AVX’s Advanced Product and Technology Center in Myrtle Beach, SC since 1992. He is currently a Member of the Technical Staff where he is leading a development program for thick film integrated passive devices. He has also worked on development of multilayer piezoelectric and electrostrictive devices. Prior to joining AVX, Mr. Ritter worked at Martin Laboratories in Baltimore, MD in development efforts for quarry blasting, ceramic armor, piezoelectric and electrostrictive devices. Prior to joining AVX, Mr. Ritter worked at Martin Marietta Laboratories in Baltimore, MD in development efforts for quarry blasting, ceramic armor, piesoelectric sonar materials and multilayer actuators for deformable mirrors. Mr. Ritter graduated from Franklin and Marshall College, Lancaster, PA, with a BA in Geology in 1977. The biography of Maureen Strawhorne is not available at the time of publication. Ben Smith is a research and applications engineer in AVX’s Corporate Marketing group in Myrle Beach, SC. His primary functions include customer design support, new product development, and product testing. Mr. Smith received his BSEE from the Georgia Institute of Technology where he specialized in RF and Microwave systems design. In his spare time, he enjoys audio engineering as well as various other engineering activities. Allen L. Templeton was born in Charlotte, NC in 1959. He received the B.S.E. in Electrical Engineering and the B.A. in Physics from the University of North Carolina at Charlotte in 1981 and the M.E. in Electrical Engineering from the University of South Carolina in 1992. He started working for AVX Corp in 1988, he was involved in the design, modelling, and testing of multilayer ceramic capacitors and integrated passive components. Currently, he is a design engineer with Philips Components in Columbia, SC. Dr. Robert H. Heistand II is the Manager of Integrated Passive Devices Research & Development at AVX Corporation’s Advanced Product & Technology Center. He is the Chairman of the Materials sub-committee of the IMAPS National Technical Committee and has served as session chair for ISHM/IMAPS on numerous occasions. Since his Ph.D. in Chemistry from Cornell University in 1981, his career has been in R&D of advanced material synthesis, fabrication and processing, mainly in ceramic, solid state and polymer materials for electronic applications. He has authored over 35 publications, holds 8 patents and brought 4 advanced material prodThe International Journal of Microcircuits and Electronic Packaging,ucts Volume Number 4, Fourth Quarter 1998 (ISSN 1063-1674) to the21, global market. 340 8 International Microelectronics And Packaging Society