Factors Influencing the Green Body Properties and Shrinkage Tolerance of LTCC Green Tapes

Low-temperature co-fired ceramics (LTCC) is a powerful technology for the manufacture of integrated electronic devices. To fulfill the needs of miniaturization, the applied materials must be of constant quality and the manufacturing processes must be well controlled. The reproducibility in shrinkage is one of the most important quality issues of LTCC tapes. To guarantee the customer a narrow shrinkage tolerance, the tape producer must know the important influencing factors of tape manufacturing on shrinkage. In this work, the effects of slurry composition, tape-casting parameters like casting speed and opening of the blades, and tape handling on the sintering shrinkage behavior were investigated by using design of experiments. The investigation showed that the green density and therefore the shrinkage values of tapes depend considerably on the variation of the solvent mixture. Furthermore, significant interactions were quantified between the tape-casting velocity as well as the particle size and the shrinkage behavior. The shrinkage values were also influenced by mechanical deformations of the tapes before firing.