The purpose of this paper is to analyse the influence of various firing profiles on microstructural and dielectric properties of low-temperature, co-fired ceramic (LTCC) substrates in a GHz frequency range. According these analyses, sintering process can be controlled and modified to achieve better performance of devices fabricated from LTCC substrates.
Samples from LTCC substrates GreenTape 951 and GreenTape 9K7 were sintered by four firing profiles. Basic firing profile recommended by the manufacturer was modified by increasing the peak temperature or the dwell time at the peak temperature. The influence of firing profile on microstructural properties was analysed according to measurements by X-ray diffractometer (application of the Cu K-alpha radiation and the Bragg-Brentano method), and the influence on dielectric properties (dielectric constant and dielectric losses) was analysed according to measurements by split cylinder resonator method at 9.7 and 12.5 GHz.
Rising of the peak temperature or extension of dwell time at this temperature has influence on all analysed properties of LTCC substrates. Size of crystallites can be changed by modification of firing profile as well as microdeformation. In addition, dielectric properties can be changed too by modification of the firing profile. Correlation between microdeformation and dielectric losses was observed.
The novelty of this work lies in finding the mutual relationship between changes in microstructural (size of grains and microdeformation) and dielectric properties (dielectric constant and dielectric losses) caused by different firing profiles.
This study was possible because of Project implementation: University Science Park TECHNICOM for Innovation Applications Supported by Knowledge Technology, ITMS: 26220220182, supported by the Research & Development Operational Programme funded by the ERDF”. The authors support research activities in Slovakia. This project was co-financed by the European Union.
This work was supported by the Slovak Research and Development Agency under the contract No. APVV-14-0085: Development of New Generation Joints of Power Electronics Using Nonstandard Sn-Based Alloys.
Pietrikova, A., Rovensky, T., Durisin, J., Vehec, I. and Kovac, O. (2017), "Influence of firing profile on microstructural and dielectric properties of LTCC substrates", Microelectronics International, Vol. 34 No. 3, pp. 127-130. https://doi.org/10.1108/MI-11-2016-0083
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