Analysis of mechanical properties of LTCC substrates

In this paper we describe the most commonly used methods for analysis the mechanical properties of 3 types LTCC substrates (DuPont 951, DuPont 9K7, MuRata) based on three- and four-point bending as well as Dynamic Mechanical Analysis (DMA). The results of analysis show that the four-point bend test indicates a distribution of stress in the substrate with more accuracy and points to the tendency of the fracture-toughness state in the material. The three-point bend test achieves higher flexural strength of tested substrates. The re-firing process applied to the LTCC type 951 increases the flexural strength by 10 %. Extension of the duration of the firing process from 4 h to 26.5 h causes increasing the flexural strength by 100 %. This work proves that the Murata has the best homogeneity and the LTCC type 9K7 has the greatest predisposition to brittle fracture at a distance of lower supports of 32 mm. The sintering process´ conditions of the ceramics have the significant influence to the shrinkage of the all tested ceramics´ types. DMA analyses of the ceramics within the elasticity range confirm the described behavior of fracture-toughness state realized by classic test methods.