Structuration of micro-fluidic devices based on low temperature co-fired ceramic (LTCC) technology

Smart packaging concept has been the driving force for the search of advanced technologies to produce multi-functional micro-scale devices for long years. In this sense, LTCC technology has been recently addressed as the suitable choice for a wide range of applications. In addition to its attractive characteristics for high-frequency applications those have been profited for a long time, it receives a growing attention for sensor applications in the recent years as well. This is due to the easy machinability of the LTCC tapes, which permits realization of complex structures such as membranes, channels, making it a suitable environment for micro-fluidic devices. These devices require utilization of supporting layers in order to prevent defects, often observed in forms of sagging, warpage or curling. The methods for elimination of these defects vary from passive precautions taken during lamination and firing to more elaborate methods such as use of sacrificial layers. The basic idea in the latter method is the preparation of a support, which can then be removed, leaving behind the desired structure. Among a number of alternatives, this paper focuses on and proposes the carbon-black sacrificial paste as an effective and simple method to fabricate membranes. Additionally determination of the open porosity elimination temperature in LTCC and effect of processing parameters on the fabricated structures, will be discussed. The methods of analysis will be TGA (thermo gravimetric analysis), dilatometer and SEM (scanning electron microscopy) analysis.

Fabrication of low-temperature co-fired ceramics micro-fluidic devices using sacrificial carbon layers

Hansu Birol, Caroline Jacq, Thomas Maeder, Peter Ryser, Sigfrid Straessler

Ease of fabrication and design flexibility are two attractive features of low temperature co-fired ceramics (LTCC) technology for fabrication of complex micro-fluidic devices. Such structures are designed and processed using different shaping methods, the extent and complexity of which depends on the final device specifications (dimensions, mechanical and functional properties). In this work, we propose a sacrificial layer method based on carbon-black paste, which burns out during the LTCC firing stage. The paper will summarize the preparation of the paste, influence of processing conditions on the final dimensions, and demonstrate the mechanically integrated structures obtained using this technique. Some of those are membranes of various diameters (7-12mm) with a thickness of 40utm and a variety of internal spacing (1 5-6outm), free-hanging thick-film resistors (TFR) bridges on LTCC for heating micro-volumes. The main methods of the study will be thermo gravimetric analysis (TGA), scanning electron microscopy (SEM) and dilatometry in addition to electronic instruments for device characterization.

2005

Fabrication of LTCC Micro-fluidic Devices Using Sacrificial Carbon Layers

Hansu Birol, Giancarlo Corradini, Yannick Fournier, Caroline Jacq, Thomas Maeder, Reynald Passerini, Peter Ryser

Ease of fabrication and design flexibility are two attractive features of low temperature co-fired ceramics (LTCC) technology for fabrication of complex micro-fluidic devices. Such structures are designed and processed using different shaping methods, the extent and complexity of which depends on the final device specifications (dimensions, mechanical and functional properties). In this work, we propose a sacrificial layer method based on carbon-black paste, which burns out during the LTCC firing stage. The paper will summarize the preparation of the paste, influence of processing conditions on the final dimensions, and demonstrate the mechanically integrated structures obtained using this technique. Some of those are membranes of various diameters (7-12mm) with a thickness of 40µm and a variety of internal spacing (15-60µm), free-hanging thick-film resistors (TFR) bridges on LTCC for heating micro-volumes. The main methods of the study will be thermo gravimetric analysis (TGA), scanning electron microscopy (SEM) and dilatometry in addition to electronic instruments for device characterization.

2005

Structuration and Fabrication of Sensors Based on LTCC (Low Temperature Co-fired Ceramic) Technology

Hansu Birol, Giancarlo Corradini, Caroline Jacq, Thomas Maeder, Peter Ryser

The purpose of this paper is to demonstrate sensors and structures fabricated using the LTCC technology, which has been addressed and employed increasingly as a smart packaging approach for several applications. The focus will be on inclination and cantilever force sensors and micro-fluidic structures. Motivation for selection of LTCC for these applications in addition to fabrication and structuring of the devices will be explained in details. TGA (thermo-gravimetric analysis), dilatometer analysis, SEM (scanning electron microscopy), electronic equipment for measuring sensor performance will be extensively used for explanation of the results. It will also be shown that, compared to classical thick-film technology on alumina, LTCC allows a considerable increase in sensitivity, and is therefore better suited for the sensing of minute forces and pressures.

Trans Tech Publications2006