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2008
Conference Paper
Titel
Generation of via holes and patterns in green foils for multilayer ceramics
Alternative
Herstellung von Verbindungslöchern und Strukturen in Grünfolien für Mehrschichtkeramiken
Abstract
Multilayer ceramics technology uses unsintered (green) ceramic foils to build up multilayer microcircuits and microsystems. Theses foils serve as carrier for screen printed circuitry and later, after sintering, as dielectric between adjacent layers. Electrical and sometimes thermal interconnection between layers is realized through connecting holes (vias), which are filled with conductive material. The generation of via holes is one of the first process steps in the fabrication of ceramic microcircuits. A few 100 up to mare than 100 000 holes with diameters ranging from 60 to 300 micron but usually around 100 micron depending on the specific application, have to be generated in 6'' x 6'' or 8'' x 8'' ceramic green sheets. Regarding the electrical functionality, there is not much need for the generation of other patterns (than holes), apart from rectangular cavities which are used to embed chips in. This is different for ceramic microsystems, where the potential of multilayer ceramics technology to build up complex complex 3-dimensional structures is used. For such applications, more complex patterns, such as fluidic channels, chambers or micromechanical elements are to be generated. This poses challenges to the respective structuring techniques and while the traditional technique of punshing is good suited to the generation of via holes, more complex patterning is the domain of laser processing. This paper will discuss characteristics of these two structuring techniques as well as present some experience gained with different layer types, which are available on the market and suitable for machining ceramic green foils.