Impact of process parameters on printing resolution and dielectric properties of LTCC substrate

Abstract

Purpose The low-temperature co-fired ceramics (LTCC) microfluidic-microwave devices fabrication requires careful consideration of two main factors: the accuracy of deposition of conductive paths and the modification needed to the standard process of the LTCC technology. Neither of them are well-described in the literature. Design/methodology/approach The first part of this paper deals with the individual impact of screen parameters such as aperture, photosensitive emulsion thickness and mounting angle on the precision of the screen-printed conductive paths fabrication. For the quantitative analysis purposes, the design of experiment method with Taguchi orthogonal array and analysis of variance was used. The second part contains the characterization of the complex permittivity measured for different values of LTCC substrates lamination pressure. Findings It can be concluded, that the combination of aperture, equal to 24 µm, emulsion thickness 20 µm and mounting angle 22.5° ensures the highest quality of printed conductive metallization. Furthermore, the obtained results indicate, that the modification of the lamination pressure does not affect significantly the dielectric parameters of the LTCC substrates. Originality/value This paper shows two aspects of the fabrication of the microfluidic-microwave LTCC devices. First, the resolution of the applied metallization is critical in manufacturing high-frequency structures. The obtained experimental results have shown that optimal screen parameters, in terms of conductive pattern quality, can be found. Second, the received outcomes indicate that the changes in the lamination pressure do not affect significantly the electrical parameters of the substrate. Hence, this effect does not need to be taken into account.

Ink-jet printed ring resonator with integrated Microfluidic components

“…As a substrate material, the LTCC Du Pont 951 with the green tape thickness of 254 µm and dielectric constant equal to 7.5 (Jasińska et al , 2019), was chosen. The substrate stack consists of four green tape layers, as illustrated in Figure 2.…”

Precision fabrication of flexible microfluidic circuits using direct laser rapid prototyping solution

“…Typical processing parameters are gathered in Table 1, for both Kapton and LTCC materials. LTCC sheets were type SK-47 produced by KEKO Equipment, the same type as already used by other groups for microfluidic applications 12,13 , and were 165 µm ± 8 µm thick. Samples are held in place with a vacuum-table system that enables mounting and processing of samples as large as 300 mm by 200 mm while maintaining the resolution, structuring speed, and small structure size across the whole sample.…”

“…Typical processing parameters are gathered in table 1, for both Kapton and LTCC materials. LTCC sheets were type SK-47 produced by KEKO Equipment, the same type as already used by other groups for microfluidic applications [12,13], and were 165 ± 8 µm thick.…”

“…Within the microfluidics field, demonstrational use-cases have been presented on widely used classic microfluidic materials, such as glass [7] and PMMA [8][9][10]. Similar applications were also demonstrated on flexible materials, such as low-temperature co-fired ceramics (LTCC) [4,[11][12][13], or for surface modifications of polyimides [14] and polydimethylsiloxane (PDMS) [15]. Patterning of polyimide materials used for microfluidic applications is commonly achieved with reactive ion etches, primarily for point-of-care devices [16], as Kapton is a biocompatible material [17,18], or even laser ablation [19].…”

An Ultrahigh Sensitive Microwave Microfluidic System for Fast and Continuous Measurements of Liquid Solution Concentrations

“…The design involves a microfluidic system and a microstrip transmission line with the 50 Ω standard for all microwave components. On the basis of our experience with LTCC materials in different microwave sensor applications (see, e.g., [ 13 ]), we chose the DuPont 951 ceramic system with green tapes of 116 µm and 254 µm in thickness ( , , @ 2.45 GHz and 5.12 GHz, values taken from the previous work of [ 27 ]). The next step was to determine the width and thickness of the microchannel and microstrip line.…”