Clive Hendricks of Intel Corporation raised concerns over the quality of high capacitance multilayered ceramic chip capacitors in his Keynote Speech at The Capacitor & Resistor Technology Symposium held in New Orleans, LA USA on March 16th, 2010.
Based upon research conducted at Intel Corporation (Chandler, AZ USA) by Yongki Min, Venkat Magadala and Tim Lane, the company has noted a disturbing trend with respect to the life expectancy of high capacitance MLCC in the 2.2 to 100 microfarad range. According to Clive Hendricks- “Up until recently, failure due to dielectric wear out was not a concern for the capacitors used to support CPUs,” in fact “our reliability models showed that the capacitors could be used for thousands of years before the insulation resistance would begin to degrade,” however, “in the past five years we have noticed a disturbing trend- as the capacitance density has increased, the usable life has reduced to hundreds, then tens and now even less than five years.”
Mr Hendricks also noted that “going forward, we see reduced reliability margins impacting capacitor supplier roadmaps and posing an increased risk for applications using decoupling MLCCs.”
The company noted that the method by which capacitance density of MLCC has increased- i.e. the stacking up of hundreds of layers of dielectric material between layers of base metal electrode has come at a cost. The trend to thinner dielectric layers has come with unwanted consequences- typically at the expense of rated voltage, and therefore it has adversely impacted the expected life of the MLCC in a circuit. The company further predicts that the MLCC industry faces keen challenges that will impede its ability to increase capacitance density while reducing rated voltage-going forward. Intel noted that X5R at 4 volt and X6S at 2.5 volt are as low as the industry will accept at this time. Intel believes that high-cap MLCC suppliers are caught in a “catch-22 situation”- to increase capacitance density they need to make thinner dielectric layers and to maintain reliability they need to reduce the grain size of the barium titanate dielectric material- which in turn will reduce the capacitance density. Intel concluded by stating that it was their opinion that the rate of progress in MLCC would be impeded going forward without a major breakthrough in the engineered materials or processing to manufacture MLCC.
Alternatives to High Capacitance MLCC are limited due to limited capacity to produce. Obviously both tantalum chip capacitors and solid polymer aluminum chip capacitors are viable alternatives to high-capacitance MLCC in the 2.2 to 100 microfarad arena, but the global capacity to produce these parts is quite limited when compared to the massive quantities of MLCC produced each year. Therefore, a breakthrough in ceramic materials and processing technology is necessary for MLCC technology to move forward to match the future requirements of CPU decoupling expected over the next 20 years.
Additional Resources: (1) Ceramic Capacitors: World Markets, Technologies & Opportunities: 2009-2014 ISBN # 1-893211-25-8 (December 2009) (2) BME MLCC: Global Markets, Technologies & Opportunities: 2005-2010 ISBN # 1-893211-74-6 (2005)