PASSIVE COMPONENT INDUSTRY JANUARY/FEBRUARY 2000
Author’s Note: This factory was sold to Kemet Electronics, seven years later.
In August 1998, EPCOS (formerly Siemens + Matsushita Components GmbH & Co. KG), of
Munich, Germany, began tantalum capacitor production at its new 175,272-square-foot facility in Évora, Portugal. The plant was built with an initial investment of $87 million and employs approximately 400. The new facility complements existing tantalum capacitor production at EPCOS’ plant in Heidenheim, Germany, which began production in 1989. At the end of 1999, the combined tantalum capacitor production of Heidenheim and Évora was 1.1 billion pieces, up from 500 million pieces at the end of 1998.
In August 1998, EPCOS initiated production of the smaller A- and Bcase- size tantalum chip capacitors for its cellular phone customers; and in January 1999 the company began production of the larger C-, D- and E-case-size tantalum chip capacitors for its automotive electronic subassembly customers. At the end of 1999, production of the smaller A- and B-case-size products (55%) exceeded production of the larger C-, D- and E-case-size products (45%) by only a small amount. By the summer of 2001, it is estimated that EPCOS will increase production of tantalum capacitors at both Heidenheim and Évora to between 1.5 billion and 2.0 billion pieces to satisfy rising demand from its core customers in cellular telephones, subscriber line interface cards, automotive electronic subassemblies and personal computers. At the end of 2002, EPCOS forecasts that 70% of its unit output of tantalum capacitors will be in Évora, with the remaining 30% in Heidenheim.
Building a New Plant at an Interesting Time
In the fourth quarter of 1998, in Prague, Czech Republic, I had the opportunity to interview Josef
Gerblinger of EPCOS’ tantalum plant in Heidenheim. I voiced the collective thoughts of EPCOS’ major competitors as to why the company would add capacity in Évora, creating additional supply at a time when demand was only 80% of worldwide capacity. After all, the economic climate for passive components was depressed—pricing for tantalum capacitors was being pushed so low as to equal the cost of the raw materials, and base-metal ceramic capacitors were rapidly encroaching on the lower-capacitance-value molded and coated chip tantalum capacitors. So why add production capacity? Dr. Gerblinger responded by saying that EPCOS would do nothing of the kind unless it had sufficient reason to believe that demand for tantalum capacitors would increase so much in the coming years that the investment in Évora would be justified. With due praise of Dr. Gerblinger and the powers that be at EPCOS, it is apparent now that the investment in Évora has paid off brilliantly. The plant is operating a tfull capacity, and the company knows that if it could produce more tantalum capacitors, it could sell them too.
The EPCOS Gamble in Évora Pays Off
EPCOS’ gamble was simple. The company believed that consumer demand for tantalum-capacitor intensive cellular telephones from such telecom giants as Nokia, Ericsson and Motorola would increase dramatically in 1999 and 2000. Forecasts also showed rising demand from Europe’s major automotive electronic sub- assembly producers—Robert Bosch, Delphi Europe, Hella, AutoLiv Svenska, Siemens, Valeo, VDO and Temic. (Tantalum capacitors are used in air bag circuits, ABS cards, engine-control units, keyless entry circuits and GPS receivers.) The predicted surge in total demand would justify a major expansion in tantalum capacitor production in Évora. Ironically, EPCOS was the only major producer of tantalum capacitors in the
world that believed the demand would actually materialize. When the production of tantalum capacitors in Évora came on line, demand for tantalum chip capacitors exceeded supply by almost 20%. EPCOS truly reaped the rewards of its foresight, nearly tripling tantalum sales from $35 million in 1998 to $90 million in 1999. Revenues in 2000 are projected to reach $140 million, an increase of 55%.
Why Portugal and Not Eastern Europe?
EPCOS’ Évora tantalum plant is located about 60 miles southwest of Lisbon, Portugal. The ride from Lisbon, past the stripped cork trees (Portugal is the world’s largest producer of wine bottle corks), is splendidly scenic and uneventful. Évora is an industrialized town with many modern production sites. The new Évora plant is located a short distance from Siemens’ electromechanical component plant, which was recently sold to Tyco, Inc. The existing distribution infrastructure established by Siemens’ electromechanical plant was a key point in the choice of Évora as the site of the new plant. However, Alfred Karlstetter of EPCOS also points out that significant concessions from the Portuguese government, with respect to employee taxes and power prices, were the final factors in the decisionmaking process. Dr. Karlstetter points out that Eastern Europe was also a consideration for the site of the new tantalum plant. However, the distribution infrastructure established by Siemens Electromechanical was in place in Portugal (one of the poorest nations in the European Community) and would have had to be developed from the beginning if the plant was built in Hungary or the Czech Republic (where AVX maintains the majority of its tantalum capacitor production).
A Tour of the Plant
The Évora tantalum plant is a case study in modern production of tantalum chip capacitors. The operation contains the latest manufacturing equipment, including computer-controlled, fully automatic systems with self supervisory process control for prefabrication, assembly and testing of tantalum chip capacitors. At Évora, there are four production lines for tantalum capacitors. The initial production line began operation in August 1998, the second in January 1999, the third in April 1999 and the fourth in January 2000.
Pellet Formulation and Sintering
As with any of the major tantalum capacitor production plants in the world (Kemet in Greenville, S.C.; AVX in Lanskrovn, Czech Republic; NEC Toyoma in Japan and Thailand; Vishay-Sprague in Sanford, Maine, and Dimona, Israel, etc.), EPCOS in Évora begins tantalum capacitor production with capacitor-grade tantalum metal powder is purchased in its purest form from one of three global vendors—Cabot Performance Materials of Boyertown, Pa.; H.C. Starck of Goslar, Germany; and Ningxia Non-Ferrous Metals of the Ningxia Province in the People’s Republic of China. Capacitor-grade tantalum metal powder is mixed with a binder/lubricant and poured into a die that has a centrally positioned contact wire, also made from tantalum (the wire forms the positive connection). The wire is pressed into an anode of prescribed weight and dimensions to accommodate the planned case size (A, B, C, D, E or some unusual variation thereof), and then baked in an inert gas to completely remove the binder. The next stage is
sintering of the pellet, which is carried out in a precision-controlled atmosphere in the range of 1,700º. Precise temperature and time control is absolutely critical in the tantalum pellet sintering process, because the lower the sintering temperature, the higher the retained surface area and therefore the higher the available capacitance. At higher sintering temperatures the pellet sinters into a more dense body, yielding less surface area but possessing a greater degree of purity and thus a lower instance of potential failure.
The formation of the tantalum pentoxide dielectric layer is accomplished through electrolysis. This process involves the immersion of the pellets in an acid solution, wherein a constant current is applied. The acid solution completely penetrates the porous pellet body, and the film of tantalum pentoxide grows on every available surface within the porous structure. Since capacitance is equal to surface area, a very high capacitance can be obtained in a very small, surface mount package. This makes tantalum capacitors somewhat unique, and they are the product of choice when high capacitance is required in a printed-circuit board that has real estate constraints. The results of the dielectric formulation process depend upon the anodization voltage that is applied to the acid solution. The anodization voltage is typically three to four times the rated voltage of the capacitor and determines the thickness of the oxide film. In turn, the thickness of the oxide film also determines the capacitance value of the finished capacitor.
Cathode development is the most time-intensive portion of tantalum capacitor production. The anodized pellets are immersed in a solution of manganese nitrate, which fully penetrates the porous body of the tantalum pellet. The impregnated anodes are then passed through an oven and baked at temperatures between 200º C and 300º C where pyroysis takes place. In this process the manganese nitrate breaks down into a layer of manganese dioxide, which in turn forms the cathode, or negative contact of the polar tantalum capacitor. This process is repeated between six and 12 times to ensure complete coverage and connection of the manganese dioxide throughout the porous pellet. After this process is complete, a layer of fine, highly conductive carbon is applied to to the surface of the anode, and then the pellet is cured. A layer of silver paint is applied and the pellet is cured again at elevated temperatures.
Encapsulation of the Silvered Anode
The silvered anodes are encapsulated with an epoxy resin that serves as a protective layer against mechanical shock and provides a barrier against penetration of chemicals, water vapor, solvents and acids. The epoxy moulding process requires that the silvered anode be attached to a formed metal lead frame with silver glue. The tantalum wire is welded to the positive termination of the lead frame, the epoxy resin is applied and the terminations are formed around the resin molded capacitor body.
Tantalum Capacitor Development at Évora
At Évora, EPCOS has developed innovative tantalum capacitor products to meet the demand of customers in the telecommunications, automotive electronic and computer industries. These developments center around high capacitance value in smaller case sizes; lower equivalent series resistance (ESR); lower profiles; and higher operating temperatures. Note that production at Évora’s sister
plant in Heidenheim was developed as a support for Siemens Automotive Group back in 1989. Product offering also developed throughout the 1990s to support Siemens’ cellular phone business. These two core product markets enabled the Heindenheim plant to venture into the merchant market to sell tantalum capacitors to major OEMs in the telecom and automotive industries. Évora is the logical extension of the success of Heidenheim in the merchant market.
Through innovation and mass production, EPCOS has developed high-capacitance tantalum capacitors in 10 μF and 47 μF in 25 Vdc and 16 Vdc respectively, for applications in ADSL modems and line cards. They have also developed high-capacitance, low-voltage products that demonstrate very low ESR, which include 100 μF at 16 Vdc and 220 μF at 10 Vdc for applications in telecommunications voice and data switching (subscriber line interface cards). EPCOS has also developed extremely high capacitance 680-μF tantalum capacitors at 6.3 Vdc in an E case size for battery load leveling in cellular phones. Other inno- vations for the cellular telephone market include lowprofile C- and D-case chips with capacitance values of 47 μF in 6.3 VDC, and 10 VDC, and 220 μF at 6.3 Vdc. EPCOS describes the growth in demand from the telecommunications industry for 1999 as astronomical.
Automotive Electronic Subassemblies
For customers in automotive electronic subassemblies, EPCOS has developed tantalum capacitors that can operate at 150º C to accommodate engine-control units in increasingly hotter under-the-hood automotive environments. The company also offers 33-μF tantalum chip capacitors at 35 Vdc in an E case size for use in air bag ignition circuits. EPCOS produces low-ESR tantalum capacitors in 220-μF and 330-μF D-case-size chips for multimedia automotive applications in GPS receivers. EPCOS estimates that it controlled almost 40% of the 1999 European automotive electronic subassembly market for tantalum capacitors, with Kemet and AVX as major competitors.
For personal computers, EPCOS has developed a 1000-μF 4-volt tantalum chip for notebook computers (battery load leveling); a 47-μF at 10 Vdc, also for notebook computers; and an extremely low profile 220 μF part at 6.3 volts, for PCMCIA card applications. EPCOS offers a 470-μF, 6.3-volt part for the output filter on computer switchmode power supplies.
Shipments From Évora
A full 75% of Évora’s tantalum capacitor production is destined for European customers; the remaining 25% is split evenly between North America and the Asia-pacific region. Because of the heavily weighted sales into the European market, EPCOS’ customer base in tantalum matches the historical strengths of the European Community, with substantial shipments to the telecommunications infrastructure, wireless communications and automotive electronic subassembly industries. Shipments by EPCOS into the computer industry are as limited as the company’s sales to the NAFTA and Asian regions and represent an area that EPCOS wishes to expand. Moreover, on a regional basis, it is EPCOS’ intention to increase its tantalum capacitor sales into the United States and the major industrialized Asian countries— South Korea, Singapore, Taiwan, Malaysia and the People’s Republic of China.
Future Plans at EPCOS
In addition to expanding market share in the NAFTA and Asian regions and increasing sales to the computer industry, EPCOS will continue to develop innovative products for customers in the telecommunications and automotive electronic subassembly industries. These developments will include higher capacitance products in increasingly smaller case sizes as well as ultra- low-ESR tantalum chips. One future direction for EPCOS will be the implementation of organic electrolytes to displace manganese dioxide cathodes. Organic electrolyte tantalum capacitors have already been developed by NEC Toyoma and Kemet Electronics. Organic electrolytes based on such polymers as polypyrole and polythiolene have been shown to reduce ESR in tantalum capacitors to an extremely low level. Even though sales of such products represented less than 5% of all unit shipments of tantalum capacitors in 1999, it is forecast that in 10 years, that the percentage could be higher than 50%.
Readers Who Came Here, Also Ventured Here: Additional Resources: (1) Tantalum Capacitors: World Markets, Technologies & Opportunities: 2010-2015 ISBN # 1-893211-11-8 (© April 2010) (2) TANTALUM: Global Market Outlook: 2008-2013 ISBN # 0-929717-81-3 (2008)