Technical Trends and Directions in the Global Capacitor Industry
10.31.2012 // Dennis M. Zogbi // Passives
Product innovation in the global capacitor industry in 2012 can be categorized into three broad categories − miniaturization, enhanced performance and integration. In fact, these three basket categories have defined the pools of innovation that have moved the components market forward and enabled key advances in portable communications: home theater, industrial, automotive and specialty electronics markets over the past 25 years. Much has been written on the advances in semiconductor technology, which is the glamorous heart of all things electronic; but little light has been shed on the volomuous support components that take up the majority of the availbale space on the printed circuit board – until now.
Innovative Raw Materials
In any breakdown of cost of goods sold related to capacitors, what immediately jumps out is the cost of raw materials. The raw materials from which capacitors get their names, otherwise knonw as “dielectrics,” include ceramic, tantalum, aluminum and plastic and are the most expensive portion of the overall cost of goods sold for any capacitor, (and can be as much as 70% of the total cost of goods sold). Over the years, capacitor manufacturers have attempted to bring their raw materials closer to their point of component manufacturing and out of the merchant market, because they fully appreciate that control over raw material usage and supply not only keeps costs down but also encourages innovation. Still, the majority of engineered capacitor dielectrics remain firmly in the merchant market and the seeds of innovation for the capacitor industry usually begin at the laboratory of the raw material vendor. The critical maxim that envelops the capacitor is its ability to hold charge, which by physics is determined by the available surface area of the given dielectric. Manipulation of these dielectrics, has been, and will continue to be at the root of technical trends driving innovation in the capacitor industry for the foreseeable future. One of the primary technical trends is component miniaturization, but not at the expense of surface area or capacitance.
The trend in component miniaturization has impacted the ceramic, tantalum, aluminum and plastic film capacitor markets, with the impact on the multilayered ceramic chip capacitor the most salient. Today, ceramic MLCC now being mass produced in the EIA 0201 and the new 01005 case size, which is half the physical size of the 0201. In tantalum capacitors, developments have centered around matching ceramic chip capacitor sizes down to EIA 0402 case sizes with greater capacitance per footprint and better reliability over time. In aluminum capacitors, the developments in lower profile vertical chip aluminum products and horizontal molded chips continues to drive innovation. In film capacitors, the technical trends still surround the developments of smaller PEN, PPS and PET film chips to displace older radial leaded designs for filtering and noise suppression. In the powder dielectrics ceramics and tantalum, the breakthrough in component miniaturization has come from the ability for materials vendors to mass produce high capacitance value raw materials. These raw materials are engineered through nano-technology, whereby powders and metals are engineered in very small and consistent particle sizes. In plastic film and aluminum foil dielectrics, the ability to extrude increasingly thinner anode foils and plastic films enables the component manufacturer to either stack up more layers, or roll up dielectrics more tightly into a given case, thereby creating smaller component footprints without compromising capacitance.
This manipulation of ceramic dielectric materials and electrode materials to create large case size ceramic chip capacitors to 100 µF also enables these ceramic capacitor manufacturers to produce extremely small ceramic chip capacitors in the EIA 0201 or 01005 case size with capacitance values to 0.1µF and 0.01 µF respectively.
In DC film capacitors there has also been increased activity in integrating X and Y capacitor functions into single element components (a single capacitor housing 2 X capacitors and 1 Y capacitors for line voltage electronics − and variations thereof). There has also been the primary focus of expanding surface mount film chip capacitor product lines in PEN, PPS and PET dielectrics, offering products with smaller case sizes and higher capacitance values. Surface mount film capacitors are being designed into such applications as cell phones, LCD backlighting, lighting ballasts, xenon headlamps and DC/DC converters.
In all capacitor dielectrics there is a continual push toward enhanced performance while working within the framework of standardized component footprints. Like artists painting on canvas, the design engineer must keep enhancing the performance of the capacitor while working within the frame of the component case size. The “frame” is important because there is much invested in “pick and place” equipment throughout the supply chain that is dedicated to handling specific component case sizes. This is why component manufacturers must continually re-evaluate the manipulation of raw materials to achieve new levels of enhanced performance. One of the leading innovative design engineers for capacitors always answers the question “What are you working on?” with “Better, smaller, faster and more cost effective!” and this answer has never changed over the past 25 years.
Higher Voltage, Higher Frequencies and Higher Temperatures
Niche capacitor manufacturers have repositioned all or part of their product offerings to offer application specific and value added capacitors in high voltage, high frequency and high operating temperature environments; so it follows that spending on research and development would follow suit. One area of focus, for example, would be in increasing the voltage per cell for double layer carbon “supercapacitors” to a level much higher than today’s standard 2.7 Vdc-which would reduce the number of cells in a given system. Another area of focus of higher voltage parts is the development of the 50 Vdc and the 63 Vdc polymer tantalum molded chip capacitor, as well as the development of the 100 kV “hockey puck” type ceramic capacitors. In higher frequency applications, developments continue to enhance the capability of capacitors for applications above 5 Ghz to the DC light spectrum, and in the more commercial markets for smartphones and for increased bandwidth, especially for ceramic capacitors that employ exotic titanate and porcelain materials. Higher temperature capacitors are also under development in traditional dielectrics, especially in ceramics and in DC film capacitors; where the threshold is now being pushed beyond the 300 degree C range to support advances in aircraft, oil well logging tools and geothermal electronics.
Higher Capacitance Products
The other major trend in capacitor dielectrics is to increase capacitance value per cubic centimeter of anode, by enhancing or improving the available surface area. This trend creates a key battleground of competition between ceramic, tantalum and aluminum capacitors in the lucrative market between 1 and 1000 microfarads. In ceramic capacitors for example, the trend among the major ceramic capacitor producersis the continued development of extremely high capacitance MLCC in the 1206 or 1210 case size with capacitance values to 100 µF and with the future target of developing 220 microfarad and even 330 microfarad MLCC in the same case size. It is also apparent that each of the major ceramic capacitor producers are attempting to produce higher capacitance products in increasingly smaller case sizes with enhanced performance (i.e. X7R, X5R or NPO). The development of these high capacitance ceramic chip devices was the direct result of the controlled manipulation of ceramic dielectric materials and nickel electrode powders, each of which have extremely small but uniform particle sizes that enable capacitor manufacturers to screen extremely thin dielectric and electrode layers in order to stack as many as 1000 of these layers in an EIA 1206 or 1210 case size. In molded tantalum chip capacitors, the same developments are under way. By creating higher capacitance tantalum metal powders, with capacitance values per gram exceeding 100,000 or even 150,000 CV/g, it enables manufacturers to produce higher capacitance molded chips in the larger case sizes and to extend the case size molded chips into newer and smaller footprints that rival ultra-small MLCC (i.e. P Case, J Case for example). In aluminum capacitors, the development of the solid polymer molded chip capacitor is also a relatively new arena, and one that is challenging manufacturers to produce smaller case sizes to rival those of tantalum and to compete directly against the tantalum dielectric with alternative etched anode foil and conductive polymer cathode aluminum chip designs.
Lower ESR Products
In tantalum capacitors new product developments and investment also continue to focus on lowering equivalent series resistance through the impregnation of organic polymer in tantalum anodes (instead of the traditional manganese cathodes) and in aluminum capacitors (instead of ecthed cathode foils). The technology behind the lowering of ESR is sophisticated and involves an advanced monomer dipping procedure or a gas infused pressurization process to coat the capacitor anode with layers of highly conductive polymer materials. These materials in turn enable the capacitor to more rapidly and effortlessly release its charge. Another method to lower the ESR in addition to the use of conductive polymer cathode materials is to place more than one anode in a molded chip. In aluminum capacitors, conductive polymers have also been employed in both a solid and liquid (hybrid) format to enhance the performance of both vertical chip and radial leaded capacitor designs.
Another major trend in capacitor development is integrated passive devices, whereby capacitance is created or enhanced in one of three ways − either through the development of components that employ capacitance, resistance and inductance in one package; the integration of capacitance into the interconnectig layers of the printed circuit board (both LTCC and FR4 apply); the more simple approach of the capacitor array, which combined components on one package to help end-users lower pick and place costs.
Integrated Passive Devices
The integrated passive device has been around for more than 20 years, and involves the creation of capacitance using silcon nitride or silicon dioxide in a silicon substrate and combining resistance layers employing advanced films, such as tantalum nitride, nickel chromium or hafnium diboride. Some additional components may also be integrated into the package that might include circuit protection and inductance for example. This process is somewhat alien to the traditional passive component manufacturer and is in fact an extension of semiconductor manufacturing techniques into the passive component market. The development of the integrated passive device can be viewed as an extension of the developments in component miniaturization by combining functions in a single component, the volumetric efficiency of the overall design improves. Another method that accomplishes this is the creation of capacitance between the interconnecting layers of the printed circuit board. In modules this is accompished using either low temperature co-fired ceramics (LTCC) or through the creation of capacitance between the organic layers of the FR4 board. Once again this process is in fact the next step in miniaturization, whereby, coluemtric efficincy is enhanced by placing components in the top, on the bottom and inside the board substrate. We also noted increased development activity in two and four element ceramic chip capacitor arrays. Arrays have been used for many years in the chip resistor market for board applications where there are high local densities of ceramic chip capacitors, such as at computer and telecom I/O ports, however in ceramic capacitors the markets are still comparably small but under continued development. In film capacitors there was the continued development of integrated X and Y capacitors into a single component for enhanced noise suppression. Another method of integration can be viewed as combining multiple anodes in a single molded chip. This is a favorite method of tantalum capacitor manufacturers to lower ESR and also increase capacitance, especially in large case size chips.
Additional Areas of Capacitor Innovation
The trends mentioned in this article show only the major innovations that gather the most in research and development dollars at capacitor manufacturers, who are in turn responding to the needs of their customers in handsets, computers, TV sets, medical devices, defense electronics, oilwell drilling, automotive electronics, renewable energy and a myraid of additional end-use markets and individual customer needs. The reader should be aware that in addition to these major trends, there are minor trends supporting the major developments and interesting offshoots of technology that are impacting the market today. One additional area of note would be the advances in the DC link capacitor used in renewable energy systems in hybrid electric vehicles. The original design for the DC link capacitor employed ten individual capacitor cells manufactured from polypropylene dielectric encased in a large metallic box. This capacitor design has evolved into a single cell device that is much smaller and lighter, but still offers the design engineer the same voltage and capacitance as the bulky original and at a lower price. Through Paumanok research we also note that even the smallest innovations are becoming increasingly more important to the capacitor innovation cycle. For example, the types of binders being employed in both ceramic and tantalum processing are under scrutiny because it is believes that faster and more controlled binder burn out can enhance the capacitance and performance of the finished capacitor. Other innovations of note, for example, would be increasing the level of quality and control further down the supply chain for capacitor raw materials. In ceramics for example, the supply chain is now reaching way down into the baryte and titanium processing to increase the quality of feedstock materials early in the supply chain process. In polypropylene, which is used for AC power film capacitors, research continues into the segmentation and patterning of the base film to help enhance the voltage capabilities of the finished capacitor. And even the seemingly mundane separator materials used in electrochemical capacitors are under scrutiny in an attempt to create better transfer of ions inside the capacitor cell.
In conclusion we note that a significant amount of innovation has been, and will continue to be applied to the development of capacitors with the main underlying theme of innovation being better, smaller, faster and more cost effective. The critical areas will continue to center around volumetric efficiency of the customers printed circuit board, which will in turn be accomplished through the application of nanotechnology to reduce component size; and through the integration of components together and into the interconnectinng substrates of the printed circuit board. Raw materials will play a key role, and we believe more component vendors will attempt to get closer to their extended supply chains and extend quality as far down the supply chain as possible. Future developments will also be enabled by the combination of large innovation processes and small steps that enhance the overal product offering, working in tandem with customers visoin of future needs and requirements.
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