Use of Titanates to Achieve a Temperature‐Stable Low‐Temperature Cofired Ceramic Dielectric for Wireless Applications

Abstract

A low-loss and near-zero temperature coefficient of resonant frequency (T f ) low-temperature cofired ceramic (LTCC) host dielectric was developed for portable consumer wireless device applications. The low T f was realized by compensating the Al 2 O 3 -filled-glass dielectric with admixtures of TiO 2 (negative temperature coefficient of dielectric constant (T )) in the starting formulation. XRD data indicated a portion of the TiO 2 in the starting formulation dissolved into the glass, and extensive formation of crystalline titanium compounds was observed via a nucleation and growth mechanism. The dissolution of TiO 2 in the glass and subsequent formation of titanium compounds was believed to result in the relatively small amount of TiO 2 required to achieve a near-zero T f in the final sintered structure.

Effects of various oxide fillers on physical and dielectric properties of calcium aluminoborosilicate-based dielectrics

“…Al 2 O 3 with an optimal content, typically ranging from 30 to 50 wt%, is known to further maximize mechanical strength and inertness to the adverse chemical environments. There have been limited reports dealing with the effects of various oxide fillers other than Al 2 O 3 , in which an identical glass is used as an LTCC constituent [7][8][9][10][11].…”

La2O3–B2O3–TiO2 Glass/BaO–Nd2O3–TiO2 ceramic for high quality factor low temperature co-fired ceramic dielectric

“…Comparing the C1 specimen sintered at 750°C with the C1 specimen [21][22][23]. Based on the EDX, XRD, and network analysis results, as shown in Fig.…”

The co-fired behaviors between Ag and glass–ceramics materials in LTCC

“…Because the silver easy diffuse in sintering process when the sintering temperature exceeded 930°C, and it maybe reduce or destroy the performance of components. But in fact, the sintering temperature of most ceramics materials is higher than 900°C, aim for reducing the sintering temperature of LTCC systems, the LTCC systems always adopt the mode of ceramics plus glass or glassceramics to decrease sintering temperature so as to meet the requirements in applications for LTCC [4][5][6][7][8][9][10].…”

“…Low-temperature co-fired ceramic (LTCC) technology is a low-cost process for fabricating multi-layers ceramic structures, which possesses several advantages making it suitable for mass-market telecommunication applications [1,2,[5][6][7][8][9][10][11][12][13][14][15]. LTCC has a number of advantages: (1) it has lower dielectric loss and controllable permittivity; (2) it is suitable to producing modules in low-cost SMT packages, including BGA technology; (3) it is to lead to high-density packaging, including integrated, printed resistors and capacitors; (4) it enables high yield, fast turnaround and reduced the size and cost of devices with three-dimension structures; (5) it has the possibility of fabricating fine conductive lines and spaces, small interconnect via, flexible 3-D designs and high dielectric layer counts, etc.…”