Effects of TiO2 on microstructures and properties of Li2O–Al2O3–SiO2 glass–ceramics for LTCC substrates

Abstract

In order to increase the flexural strength and to adjust the coefficient of thermal expansion (CTE), TiO 2 was introduced into Li 2 O-Al 2 O 3 -SiO 2 (LAS) glass-ceramics to satisfy LTCC applications. The effects of TiO 2 addition on the microstructure, thermal, mechanical and electrical properties were studied. The results showed that the crystal phases were composed of Li 2 OAl 2 O 3 7.5SiO 2 (major), as well as TiO 2 and CaMgSi 2 O 6 (minor). The crystal phase TiO 2 having higher CTE value could appropriately increase the CTE value of LAS to fit the silicon and remarkably improve the flexural strength of LAS glass-ceramic with low CTE. The dielectric and insulating properties also strongly depended on the amount of TiO 2 . LAS glass-ceramic sintered at 800°C with high performances was achieved in the case of 1 wt% TiO 2 : a = 2.56 9 10 -6 /°C, r = 151 MPa, e = 6.8, tand = 1.731 9 10 -3 , q = 8.29 9 10 10 X cm.

Lithium aluminosilicate (LAS) glass-ceramics: a review of recent progress

“…The recent works in LAS-based LTCC materials can be classified into following categories: (1) addition of MgO [227], CaO [230], ZnO [226,232], Cr 2 O 3 [2], ZrO 2 [233], TiO 2 [229], B 2 O 3 [3] in LAS glass, (2) borosilicate-based LAS composite [225], (3) mixing two type of glass for the coprecipitation of LAS phase and other ceramic phase [234], (4) mixing LAS with active dielectric ceramic material (commercial dielectric materials [217], cordierite [222], alumina [220,221]). Table 6 presents the sintering tempering temperature, dielectric properties, thermal expansion between 25°C and 300°C, and flexural strength of the recent developments in LAS-based LTCC or Ultra low temperature co-fired ceramic (ULTCC) systems in comparison with commercial products.…”

INFLUENCE OF THE CaO CONTENT IN GLASS ON THE SINTERABILITY AND PROPERTIES OF A GLASS/Al₂O₃ COMPOSITE FOR LTCC APPLICATIONS

“…The low-temperature co-fired ceramic (LTCC) technology is a multilayer substrate process technology that can be used to manufacture three-dimensional ceramic modules embedded with highly conductive metal electrodes and passive components [3,4]. At the same time, LTCC materials have a lower sintering temperature, coefficient of thermal expansion (CTE) which when adapted to semiconductor materials of high thermal conductivity, are suitable for electronic substrate packaging [5,6]. In order to realise the miniaturisation of electronic substrates, LTCC materials are required to have excellent mechanical properties to ensure mechanical reliability against assembly stress and drop impacts [7].…”

Ultrahigh hardness Li2O–MgO–Al2O3–SiO2 glass–ceramics containing multiphase nanocrystals

“…[24][25][26] In addition, the glass-ceramics also could be easily ion-exchanged for further strength enhancement due to a suitable Li 2 O content. [27][28][29][30][31][32][33] The crystallization processes, crystal phase, thermal expansion, and strength properties were determined by glass compositions of LAS glasses, which have been broadly investigated. [34][35] Chen et al 36 studied the effect of Li 2 O content in LAS glass on the crystal phase and CTE and found β-quartz solid solution-based crystal phases precipitation in glass-ceramics, and CTE in 30-300 • C range decrease with Li 2 O content increase.…”

“…Specific nanoscale crystals containing glass–ceramics were also highly transparent for screen cover protection 24–26 . In addition, the glass–ceramics also could be easily ion‐exchanged for further strength enhancement due to a suitable Li 2 O content 27–33 . The crystallization processes, crystal phase, thermal expansion, and strength properties were determined by glass compositions of LAS glasses, which have been broadly investigated 34–35 .…”