Control of Silver Diffusion in Low-Temperature Co-Fired Diopside Glass-Ceramic Microwave Dielectrics

Abstract

Electrode material for low-temperature co-fired diopside glass-ceramic used for microwave dielectrics was investigated in the present work. Diffusion of silver from the electrode to diopside glass-ceramics degrades the performance of the microwave dielectrics. Two approaches were adopted to resolve the problem of silver diffusion. Firstly, silicon-oxide (SiO2) powder was employed and secondly crystalline phases were chosen to modify the sintering behavior and inhibit silver ions diffusion. Nanoscale amorphous SiO2 powder turns to the quartz phase uniformly in dielectric material during the sintering process, and prevents the silver from diffusion. The chosen crystalline phase mixing into the glass-ceramics enhances crystallinity of the material and inhibits silver diffusion as well. The result provides a method to decrease the diffusivity of silver ions by adding the appropriate amount of SiO2 and appropriate crystalline ceramics in diopside glass-ceramic dielectric materials. Finally, we used IEEE 802.11a 5.8 GHz as target specification to manufacture LTCC antenna and the results show that a good broadband antenna was made using CaMgSi2O6 with 4 wt % silicon oxide.

Characterization of Glass Insulating Thick Films with Ag Conductors for Multilayer Packages

“…However, Ag, as a conductor in a thick-film multilayer structure, also experiences several challenges. Ag will diffuse into the substrate material, thereby resulting in the degradation of performance [8][9][10]. Glass ceramic is generally used as an insulating material, which can adjust the coefficient of thermal expansion and control crystallization so as to control the diffusion of metal in the interior [4,5].…”

Improved microwave dielectric properties of CaMgSi2O6 ceramics through CuO doping

“…These drawbacks directly limit the practical use of the CaMgSi2O6 ce-ramics. In order to improve the microwave dielectric properties, Al2O3, CoO and ZnO were used to dope/substitute CaMgSi2O6 ce-ramics [8,10,11]. However, the CaMgSi2O6eAl2O3, Ca(Mg0.92x CoxAl0.08) and CaMg1-xZnxSi2O6 ceramics exhibited the low Qf values of ~60132, 60125 and 76100 GHz, respectively.…”

Joints realized by sintering of pressureless Ag paste

“…Sintered silver paste with appropriate properties can replace expensive SnAu solders while maintaining the thermal performance and excellent quality of the joint (Pietriková et al, 2011;Girašek and Pietriková, 2016). A nanoscale pressureless silver paste was developed for replacing a pressure assisted micro-sized silver paste as well (Chou et al, 2017). Application of pressure during the paste sintering puts increased demands on production in the industry automation (Das et al, 2008;Felba, 2018;Göbl, 2009).…”