LTCC Resistors – The Influence of Production Conditions on the Absolute Value and its Reproducibility

Among other virtues like good microwave performance, high density of integration, good thermal conductivity, hermeticity, and robustness, LTCC technology (Low Temperature Co-fired Ceramic) facilitates the integration of passive components like resistors, capacitors and inductors inside the multilayer stack. This option is further increasing the density of integration and improving RF- and microwave capabilities. However, these components rely on special materials (e.g. resistor paste, high-k dielectrics) which are more sensitive to changes in process parameters than standard LTCC tapes and conductor pastes. This paper focusses on resistors embedded in LTCC. It will describe the DOE (design of experiment) for the comparison of the identical resistor test coupon manufactured in three different sites under the same conditions. The test coupon includes typical resistor dimensions for microwave circuits as well as the dimensions that are used by the material manufacturer to test compliance with specifications. A selection of the measurement results of this extensive comparative study is presented and evaluated.