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In order to meet the emission legislation, in today's diesel cars diesel particulate filters (DPFs) have to be installed. Soot is filtered in the pores of ceramic wall-flow filters, but to avoid clogging, DPFs must be regenerated. By increasing the exhaust temperature, sorbed soot is burned off. An efficient control strategy depends on the knowledge of the amount and the location of soot inside the DPF. We present initial tests of a novel method to measure directly the soot load inside a filter. By electrically connecting single walls of the ceramic filter, a resistance measurement is possible. Soot particles form conductive paths inside the DPF channels. The measured values depend on the amount of soot stored inside the filter. In a special setup, we prepared connections over the lateral axis of a DPF. It is possible to get an insight view of a DPF, e.g., one clearly sees how soot trapping starts at the outlet side of the filter.

A solid-state potentiometric CO 2 -sensor of the type CO 2 , O 2 , Au, Li 2 CO 3 -BaCO 3 | Nasicon | Na 2 Ti 6 O 13 -TiO 2 , Au, O 2 , CO 2 was fully manufactured in planar thick-film technology. Due to an integrated screen-printed heater on the rear side, the sensor can be applied in a small tube for breath analysis, despite its high working temperature of 525 °C. The sensor is insensitive to variations of the oxygen partial pressure and follows strictly the Nernst equation. Based on this behavior, the presented sensor cell is suitable for exhale air analysis.

Electronic products are getting smaller and smaller, this at the same time, when their functionality seems to rise continuously. The basis for that development is continuing miniaturization, function integration and high density interconnection in electronic packaging. Ceramic interconnection technology, such as low temperature cofiring ceramics (LTCC), may be a niche technology, but one which offers a range of unique features. It is used for applications, where reliability, miniaturization, and RF capability is of premier importance, such as automotive, military, space and medical electronics. Although the potential of high interconnection density is one of LTCCs current advantages, a further reduction in feature size is postulated. As one consequence, layer to layer interconnections (vias) have to be reduced in size. Via diameters down to 100 microns are already common in state of the art production lines. Scientific papers have recently reported the fabrication of micro vias with a diameter of 50 microns. But roadmaps indicate the need for an even further reduction of via diameters well below 50 microns. The presented paper deals with research works to fabricate vias in LTCC-tape with diameters of 50 microns and below. The fabrication of the via hole itself by mechanical punching or laser drilling is discussed. The subsequent process steps of via filling, fine line printing, stacking, lamination and sintering are addressed as well. Test substrates with 50 micron vias and 80 micron lines on HeraLocktrade tapes have been produced. The overall goal of the works is to assess the fabrication of smallest vias in LTCC tape and explore the feasibility and current technological limits of today's manufacturing technologies

Today LTCC (Low Temperature Co-fired Ceramics) Technology is established as a key technology for ceramic based interconnects on modules and components. Known for their excellent thermal and high frequency electrical performance, LTCC Technology is gaining new applications e.g. in the automotive and telecommunications market. Over the last years, LTCC materials and production processes have been further developed to meet the needs of these applications. As a result, the layouts of LTCC-modules are characterized by increasing circuit complexity and packaging density. Accordingly, the numbers of layers and vias are increasing, while the dimensions of the circuitry (lines and spaces) are decreasing. On the other side, conventional screen printing is limited to approximately 100 mum of line width (in volume production). This is why photoimageable thick film technology is used in applications requiring high packaging density. Another consequence of shrinking circuit dimensions is the need to reduce the size of via holes, which are usually fabricated by punching or laser drilling. This paper reports results regarding the formation of vias in LTCC tapes. Different methods, i.e. mechanical punching and laser drilling, as well as different lasers (CO2, Nd-YAG and UV) are compared..