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Journal ArticleDOI

Fabrication of Precise Fluidic Structures in LTCC

01 Jan 2009-International Journal of Applied Ceramic Technology (Blackwell Publishing Inc)-Vol. 6, Iss: 1, pp 18-23
TL;DR: In this article, the authors describe the fabrication process used to create the precise channel and jet structures used in these LTCC-based coolers, as well as some of the challenges associated with these processes, including the erosion of the copper coolers by the coolant, a requirement for the use of deionized water within the system, and a significant CTE mismatch between the diode bar and the metal cooler.
Abstract: A number of emerging applications of low-temperature co-fired ceramic (LTCC) require embedded fluidic structure within the co-fired ceramic and or precise external dimensional tolerances. These structures enable the control of fluids for cooling, sensing, and biomedical applications, and variations in their geometry from the design can have a significant impact on the overall performance of the devices. One example of this type of application is a multilayer cooler developed recently by the authors for cooling laser diode bars. In many laser systems, laser diodes are the primary emitters, or assemblies of these diode bars are used to pump traditional laser crystals such as Nd:YLF. Assemblies of these diodes require large amounts of electrical current for proper operation, and the device operating temperature must be carefully controlled in order to avoid a shift in the output wavelength. These diodes are packaged into water-cooled assemblies and by their nature dissipate enormous amounts of heat, with waste heat fluxes on the order of 2000 W/cm2. The traditional solution to this problem has been the development of copper multilayer coolers. Assemblies of laser diodes are then formed by stacking these diode bars and coolers. Several problems exist with this approach including the erosion of the copper coolers by the coolant, a requirement for the use of deionized water within the system, and a significant CTE mismatch between the diode bar and the metal cooler. Diodes are bonded to these metal structures and liquid coolant is circulated through the metal layers in order to cool the diode bar. In contrast, the coolers developed by the authors utilize fluid channels and jets formed within LTCC as well as embedded cavity structures to control the flow of a high-velocity liquid and actively cool the laser diode bars mounted on the surface of the LTCC.† The dimensional tolerances of these cooler assemblies and complex shapes that are used to control the fluid can have a significant impact on the overall performance of the laser system. This paper describes the fabrication process used to create the precise channel and jet structures used in these LTCC-based coolers, as well as some of the challenges associated with these processes.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a fully automated low temperature co-fired ceramic (LTCC) based microfluidic system with an integrated electrochemical biosensing platform for the detection of cortisol was presented.
Abstract: This paper presents a fully automated low temperature co-fired ceramic (LTCC) based microfluidic system with an integrated electrochemical biosensing platform for the detection of cortisol. This paper presents the design, fabrication, integration and testing of the integrated 3D microfluidic system. The electrochemical immunosensor consists of microfabricated interdigitated Au electrodes, onto which cortisol antibodies are immobilized using a self-assembled monolayer (SAM) matrix of dithiobis(succinimidyl propionate) (DTSP). Finite element based simulation was used to optimize the fluid flow dynamics and washing efficiency required for immunosensing in the LTCC microfluidic assay chamber. Cortisol was used as a model analyte to demonstrate electrochemical immunosensing in a fully automated microfluidic system. Cortisol was detected in a linear range of 10 pM–100 nM at a sensitivity of 0.207 μA/M using cyclic voltammetry (CV). This system establishes the basis for the development of a POC cortisol sensor.

115 citations

Journal ArticleDOI
TL;DR: In this paper, the challenges in fabricating 3D structures in a multi-layer ceramic substrate are discussed and an overview of the current state of the art in patterning and lamination techniques for the fabrication of these three-dimensional structures is provided.
Abstract: Three-dimensional structures in a multi-layer ceramic substrate are important in realizing ceramic-based meso- and micro-systems. During lamination and/or co-firing, three-dimensional structures, especially those with suspended structures, tend to deform and sag due to the intrinsic nature of the green (un-fired) ceramic material. Fabrication of three-dimensional structures with well-controlled dimensional stability and mechanical integrity remains a challenge. This paper discusses the challenges in fabricating structures in a multi-layer ceramic substrate. An overview is provided of the current state of the art in patterning and lamination techniques for the fabrication of these three-dimensional structures.

87 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present an overview on LTCC technology and give a detailed summary on physical quantity sensors fabricated using LTCC technique, which can be used in the manufacturing of various microelectronic devices.
Abstract: Low Temperature Co-fired Ceramics (LTCC) is one of the microelectronic techniques. This technology was initially developed as an alternative to Printed Circuit Boards (PCB) and classical thick-film technology, and it has found application in the fabrication of multilayer ceramic boards for electronic devices. Fast and wide development of this technology permitted the fabrication of 3D mechanical structures and integration with various different processes. Thanks to this, LTCC has found application in the manufacturing of various microelectronic devices. This paper presents an overview on LTCC technology and gives a detailed summary on physical quantity sensors fabricated using LTCC technique.

64 citations

Journal ArticleDOI
TL;DR: In this article, the authors describe the application of laser micromachining techniques for the fabrication of microfluidic channels in low temperature co-fired ceramic, LTCC, technology.
Abstract: This paper describes the application of laser micromachining techniques for the fabrication of microfluidic channels in low temperature co-fired ceramic, LTCC, technology. It is shown that embedded cavities can be successfully realised by employing a recently proposed progressive lamination process with no additional fugitive material. Various microfluidic structures have been fabricated and X-ray imaging has been used to assess the quality of the embedded channels after firing. The problem of achieving accurate alignment between LTCC layers is addressed such that deeper channels, spanning more than one layer, can be fabricated using a pre-lamination technique. A number of possible applications for the presented microfluidic structures are discussed and an H-filter particle separator in LTCC is demonstrated.

38 citations

Journal ArticleDOI
TL;DR: In this article, a method for dopamine detection based on polydopamine (poly(DA)) formed on the surface of graphene quantum dots (GQDs) was developed.
Abstract: A convenient fluorescence sensing strategy for dopamine (DA) detection was developed based on polydopamine (poly(DA)) formed on the surface of graphene quantum dots (GQDs). The prepared GQDs were highly luminescent due to the planar structure in aromatic molecules. The ceramic-based miniature biosensor was designed and constructed through the immobilization of laccase in an electrochemically synthesized polymer − poly[dithienotetraphenylsilane] based on low temperature co-fired ceramics technology (LTCC). This sensing system utilized the catalytic oxidation of DA to dopamine- o -quinone (DOQ), and then to poly(DA) (in alkaline conditions), which can selectively quench the strong luminescence of GQDs owing to Forster resonance energy transfer (FRET). The detection process was based on substarte oxidation in the presence of the enzyme − laccase. In optimized conditions, the analytical performance illustrated high sensitivity, selectivity in a broad linear range with detection limit of 80 nM. Moreover, the method was successfully applied to test labeled pharmacological samples for DA.

32 citations

References
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Journal ArticleDOI
TL;DR: In this paper, a three dimensional LTCC (Low Temperature Co-fired Ceramics) based micro-reactor with immobilized enzyme (urease) is presented, which consists of two chambers separated by a threshold.
Abstract: A novel three dimensional LTCC (Low Temperature Co-fired Ceramics) based microreactor with immobilized enzyme (urease) is presented in this paper. The microreactor consists of two chambers separated by a threshold. The shape of the chambers was optimized by the Finite Elements Method. The modeling has brought a better understanding of the microflow of chemically modified glass or polymeric beads through the microreactor. The modeling results are verified by the observation of the fluid movement inside the real structure via a top transparent polymer layer. Moreover, immobilization techniques of enzymes on polymeric beads are investigated. Finally, the properties of the LTCC microreactor are compared with the properties of a similar one made in silicon.

26 citations

Journal ArticleDOI
TL;DR: In this paper, an integrated microfluidic lyser using LTCC technology has been fabricated, which enables the use of aqueous buffers at high temperatures without boiling by using a pressurized system.
Abstract: As an alternative material to glass, silicon, and plastics, Low Temperature Cofired Ceramic (LTCC) substrate technology is becoming increasingly important for enabling microfluidic microsystems and devices for integrated chemical and biological analysis. LTCC's simple fabrication method and unique ability to withstand high temperatures and high pressures make it well-suited for applications not possible with traditional materials. As part of Sandia's initiative to develop an automated sample preparation system for the μChemlab™ bioagent detector, an integrated microfluidic lyser using LTCC technology has been fabricated, which enables the use of aqueous buffers at high temperatures without boiling by using a pressurized system. Thermal lysing of bacterial spores in a flow-through microfluidic device at temperatures as high as 220°C and pressures up to 10.3 MPa (1,500 psi) represents a new method for solubilizing spore proteins for identification and analysis, eliminating the reliance on harsh chemical red...

14 citations

01 Jan 2006
TL;DR: In this article, an integrated microfluidic lyser using LTCC technology has been fabricated, which enables the use of aqueous buffers at high temperatures without boiling by using a pressurized system.
Abstract: As an alternative material to glass, silicon, and plastics, Low Temperature Cofired Ceramic (LTCC) substrate technology is becoming increasingly important for enabling microfluidic microsystems and devices for integrated chemical and biological analysis. LTCC's simple fabrication method and unique ability to withstand high temperatures and high pressures make it well-suited for applications not possible with traditional materials. As part of Sandia's initiative to develop an automated sample preparation system for the μChemlab™ bioagent detector, an integrated microfluidic lyser using LTCC technology has been fabricated, which enables the use of aqueous buffers at high temperatures without boiling by using a pressurized system. Thermal lysing of bacterial spores in a flow-through microfluidic device at temperatures as high as 220°C and pressures up to 10.3 MPa (1,500 psi) represents a new method for solubilizing spore proteins for identification and analysis, eliminating the reliance on harsh chemical red...

13 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe the development of "smart" channels that can be used simultaneously as a fluid channel and as an integrated chemical, temperature, and flow sensor, and the uniqueness of this device lies in the fabrication and processing of low-temperature co-fired ceramic (LTCC) materials that act as the common substrate for both the sensors and the channel itself.
Abstract: This paper describes the development of “smart” channels that can be used simultaneously as a fluid channel and as an integrated chemical, temperature, and flow sensor. The uniqueness of this device lies in the fabrication and processing of low-temperature co-fired ceramic (LTCC) materials that act as the common substrate for both the sensors and the channel itself. Devices developed in this study have employed rolled LTCC tubes, but grooves or other channel shapes can be fabricated depending on the application requirements. The chemical transducer is fabricated by depositing a conductive polymer “ink” across a pair of electrodes that acts as a chemical resistor (chemiresistor) within the rolled LTCC tube. Volatile organic compounds passing through the tube are absorbed into the polymers, causing the polymers to reversibly swell and change in electrical resistance. The change in resistance is calibrated to the chemical concentration. Multiple chemiresistors have been integrated into a single smart channel...

6 citations

Journal ArticleDOI
TL;DR: In this paper, a miniature electrochemical cell has been designed, constructed, and tested for functionality, which was used in identifying and selecting chemical species in solutions using low temperature co-fired ceramic (LTCC) material using gold for the electrodes.
Abstract: The miniaturization of analytical instruments and packaging of novel sensors is an area that has attracted significant research interest and offers many opportunities for product commercialization. Electrochemical sensors have been used to detect a wide variety of compounds including toxic gases. A miniature electrochemical cell has been designed, constructed, and tested for functionality. The cell will be used in identifying and selecting chemical species in solutions. The cell was constructed of low temperature co-fired ceramic (LTCC) material using gold for the electrodes. Tests performed in sulfuric acid and sea water solutions show that the cell is functioning based on cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis. Miniaturization allows the cell to be deployed as a sensor in many different environments.

1 citations