Joining of Sintered Alumina Substrates and LTCC Green Tapes via Cold Low Pressure Lamination

2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000268-000274
Author(s):  
Michael Hambuch ◽  
Frieder Gora ◽  
Karin Beart ◽  
Frieder Wittmann ◽  
Andreas Roosen
Keyword(s):  
Heat Conductivity ◽  
Heat Dissipation ◽  
Low Pressure ◽  
Adhesive Tape ◽  
Sintered Ceramic ◽  
Multilayer Systems ◽  
Ceramic Substrates ◽  
Adhesive Film ◽  
Lamination Process ◽  
Materials Used

In microelectronics there is a continuous trend for devices of higher integration and improved heat dissipation. For the manufacture of ceramic based microelectronic devices the following technologies can be applied. Thick-film hybrid technology uses sintered ceramic substrates, mostly Al2O3, which are screen printed with functional pastes, followed by firing at 850 °C. Alumina substrates provide very good heat conductivity (25 W/mK), but there are only two sides to carry a metallization. An improved miniaturization can be accomplished by multilayer systems using the LTCC technology. LTCC devices are manufactured by screen-printing, stacking and lamination of ceramic green tapes, followed by co-firing. A drawback of LTCCs is their low heat conductivity (3 W/mK) due to their high glass content. By combining hybrid and LTCC technology the advantages of both methods like good thermal conductivity and high multilayer integration, can be joined. Because the failure rate is too high to laminate green tapes on sintered ceramic substrates via thermo compression, Cold Low Pressure Lamination (CLPL) has been used as an alternative lamination process. CLPL is a lamination method, where the joining of the components is performed at room temperature by application of very low pressure (<5 MPa) by using a double sided adhesive tape. During heat treatment the adhesive film keeps the tapes together until the adhesive is completely decomposed; during further temperature increase the tapes are joined by sintering. The paper describes the materials used and processing steps to join the sintered material with the green tapes and discusses effects which occur during firing. These effects like edge curl and crack formation are mainly due to stresses which occur during constrained sintering. Their control can be influenced by changing process parameters.

scholarly journals Joining of Electrodes to Ultra-Thin Metallic Layers on Ceramic Substrates in Cryogenic Sensors

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4919
Author(s):  
Marcin Lebioda ◽  
Ryszard Pawlak ◽  
Jacek Rymaszewski
Keyword(s):  
Cryogenic Temperatures ◽  
Thermal And Mechanical Properties ◽  
Reflow Soldering ◽  
Ceramic Substrates ◽  
Temperature Range ◽  
Wave Soldering ◽  
Materials Used ◽  
Standard Designs ◽  
Electrical Connections ◽  
Method Show

Microjoining technologies are crucial for producing reliable electrical connections in modern microelectronic and optoelectronic devices, as well as for the assembly of electronic circuits, sensors, and batteries. However, the production of miniature sensors presents particular difficulties, due to their non-standard designs, unique functionality and applications in various environments. One of the main challenges relates to the fact that common methods such as reflow soldering or wave soldering cannot be applied to making joints to the materials used for the sensing layers (oxides, polymers, graphene, metallic layers) or to the thin metallic layers that act as contact pads. This problem applies especially to sensors designed to work at cryogenic temperatures. In this paper, we demonstrate a new method for the dynamic soldering of outer leads in the form of metallic strips made from thin metallic layers on ceramic substrates. These leads can be used as contact pads in sensors working in a wide temperature range. The joints produced using our method show excellent electrical, thermal, and mechanical properties in the temperature range of 15–300 K.

Nano-Thermometry: Transmission Electron Microscopy of Femtosecond Laser Irradiated Co/Si Multilayer Thin Foils

2005 ◽  
Vol 899 ◽  
Author(s):  
Yoosuf Picard ◽  
Steven M. Yalisove
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Amorphous Silicon ◽  
Heat Dissipation ◽  
Crystalline Silicon ◽  
Pulse Length ◽  
Multilayer Systems ◽  
Hole Edge ◽  
Thin Foils ◽  
Transmission Electron

AbstractPre-thinned foils composed of amorphous silicon and polycrystalline cobalt were irradiated using femtosecond pulse-length lasers at fluences sufficient for ablation (material removal). The resultant ablated hole and surrounding vicinity was studied using transmission electron microscopy to determine modifications to the structure. Evidence of cobalt silicide formation was observed within a 3 micron radius of the laser hole edge by use of selected area electron diffraction (SAED). In addition, elongated grains of crystalline silicon was observed within 500 nm of the laser hole edge, indicating melting of the amorphous silicon and heat dissipation slow enough to allow recyrstallization. This initial work demonstrates the use of pre-designed nanostructured multilayer systems as a method for nanoscale profiling of heat dissipation following pulsed laser irradiation.

scholarly journals Heat Transfer Characteristics of Aluminum Sputtered Fabrics

2018 ◽  
Vol 13 (3) ◽  
pp. 155892501801300 ◽  
Author(s):  
Hye Ree Han ◽  
Yaewon Park ◽  
Changsang Yun ◽  
Chung Hee Park
Keyword(s):  
Heat Transfer ◽  
Heat Dissipation ◽  
Ambient Air ◽  
Heat Transfer Characteristics ◽  
Transfer Coefficients ◽  
Hot Plate ◽  
Multilayer Systems ◽  
Heat Transfer Coefficients ◽  
Transfer Characteristics ◽  
Shape Memory Polyurethane

Al was sputtered onto four substrates: nylon, polyester, cotton/polyester, and shape memory polyurethane nanoweb, and the heat-transfer characteristics of the resultant materials were investigated by surface temperature measurements. The thickness of the Al layer increased linearly with sputtering time. The heat-transfer mechanisms of the multilayer systems in terms of conduction, convection, and radiation were investigated under steady-state conditions using a hot plate as a heat source in contact with Al-sputtered fabrics. The Al-sputtered fabric was placed on the hot plate, which was maintained at 35°C, and exposed to open air, which was maintained at 15°C. The temperatures of the air-facing surfaces of hot plate-Al-fabric-air (i.e., Al-phase-down) and hot plate-fabric-Al-air (i.e., Al-phase-up) systems were used to investigate the heat-transfer mechanism. It was found that heat dissipation to ambient air was much higher for the Al-phase-up system than for the Al-phase-down system. Heat-transfer coefficients of the Al surfaces were calculated and found to increase with the thickness of the Al layer. Furthermore, different conductive thermal resistances were observed for different fabrics prepared with the same Al-sputtering time. Consequently, differences in their thicknesses pore sizes, and thermal conductivities were suggested to have significant effects on their heat-transfer properties.

In-situ low pressure oxygen annealing of YBa2Cu3O7−δ single- and multilayer systems

1995 ◽  
Vol 243 (1-2) ◽  
pp. 24-28 ◽  
Author(s):  
G. Ockenfuβ ◽  
R. Wördenweber ◽  
T.A. Scherer ◽  
R. Unger ◽  
W. Jutzi
Keyword(s):  
Low Pressure ◽  
Multilayer Systems ◽  
Oxygen Annealing ◽  
Pressure Oxygen

Development of Cu Coating on Ceramic Substrates by Low Pressure Cold Spray and its Deposition Mechanism Analysis

2021 ◽  
Vol 1016 ◽  
pp. 1703-1709
Author(s):  
Minjae Yu ◽  
Yuji Ichikawa ◽  
Kazuhiro Ogawa
Keyword(s):  
Cold Spray ◽  
Composite Powder ◽  
Low Pressure ◽  
Metallic Powder ◽  
Thermal Processes ◽  
Deposition Technique ◽  
Composite Powders ◽  
Aluminum Composite ◽  
Ceramic Substrates ◽  
Metallic Powders

Cold spray (CS) is a solid-state deposition technique of micron-sized metallic powder in an ultra-high velocity gas using a de Laval nozzle. CS is a unique deposition technique due to its use of relatively lower gas temperatures in comparison to other thermal processes. Consequently, high-temperature oxidation and phase transformations of deposited powders are largely restricted while the operating cost of CS is much lower than that of other thermal processes. Generally, the low pressure cold spray (LPCS) technique is used for the deposition of metallic powders on metallic substrates, while only a few studies of metallic particle deposition on ceramic substrates have been conducted, and it was found that the deposition of metallic powders on ceramic substrates was quite difficult. In this study, improved LPCS deposition of copper coatings on zirconia substrates was investigated. It is known that deposition of a metallic powder on a ceramic substrate is difficult due to the differences in material bonding and several properties of the two materials. These difficulties in LPCS deposition were solved using three different approaches, namely 1) use of copper and aluminum composite powders and 2) laser pre-treatment and 3) laser texturing of zirconia substrates. It was found that pure copper powder coatings on the as-received and various treated substrates were delaminated in the interface as expected. However, the deposition was improved for all substrates by using the copper and aluminum composite powder. While the laser pre-treated substrate was not effective for the deposition of the copper and aluminum composite powder, thick coatings were obtained for the deposition on the laser pre-treated with heat treatment substrate and the laser-textured substrate.

Realisation of Large Cavities in Multilayer Ceramics by Cold Low Pressure Lamination and Their Characterisation by μCT

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000263-000268 ◽  
Author(s):  
Ulrike Deisinger ◽  
Tobias Fey ◽  
Andreas Roosen
Keyword(s):  
High Frequency ◽  
Room Temperature ◽  
Low Pressure ◽  
Multilayer Structures ◽  
Adhesive Tape ◽  
Microelectronic Devices ◽  
Micro Fluidics ◽  
Internal Cavities ◽  
Micro Reactors

In microelectronics the ceramic multilayer technology is frequently used as it allows a precise and yet flexible production of MEMS, microelectronic devices, micro reactors or devices for micro fluidics. During production of those multilayer structures the single layers are typically laminated by thermo-compression. However, large cavities cannot be realised using thermo-compression without adding sacrificial fillings. In contrast, the cold low pressure lamination (CLPL) technique allows lamination at room temperature without applying a high pressure. As in this lamination technique no mass flow occurs, internal cavities are not destroyed during the lamination step. In this study, commercially available LTCC green tapes were structured using a milling plotter with a high frequency spindle. Different process parameters (milling speed, spindle frequency) were evaluated regarding the accuracy of shape and quality of the channel edge. Channels with various dimensions (2.5 - 15 mm width and 30 mm length) were milled into the green tapes. Subsequently, the green tapes were laminated using the CLPL technique. With CLPL adjacent ceramic green tapes are joined by a double sided adhesive tape, which is applied by a soft roller. By alternately applying green (structured or unstructured) and adhesive tapes multilayer structures with internal cavities are formed. For characterisation of the sintered LTCC structures μCT (computed tomography) was used to analyse the internal structure without destroying the sample. Influence of sintering regime on deformation was evaluated. It was shown that milling of green tapes in combination with CLPL is a suitable method to fabricate internal cavities in LTCC multilayer structures.

Influence of the Low-Pressure Cold Spray Operation Parameters on Coating Properties in Metallization of Ceramic Substrates Using Copper and Aluminum Composite Powder

2021 ◽  
Author(s):  
Minjae Yu ◽  
Hiroki Saito ◽  
Chrystelle Bernard ◽  
Yuji Ichikawa ◽  
Kazuhiro Ogawa
Keyword(s):  
Cold Spray ◽  
Copper Content ◽  
Composite Powder ◽  
Pure Copper ◽  
Low Pressure ◽  
Gas Pressure ◽  
Copper Metallization ◽  
Power Module ◽  
Aluminum Composite ◽  
Ceramic Substrates

Abstract The low-pressure cold spray (LPCS) technique could be an attractive method for copper metallization of ceramic substrates to power module applications due to its one-step quick and lowtemperature process. However; manufacturing pure copper coating on a ceramic substrate by LPCS is still challenging due to its low deposition efficiency and poor adhesion strength. Our previous study successfully demonstrated the possibility of obtaining a zirconia substrate's metallization by using a feedstock powder mixture of copper and aluminum. However; the copper content in the coating was not high enough for power module applications. Therefore; in this study; we aim to improve the copper content in the coating layer composed of the composite powder deposited by LPCS on alumina and zirconia substrates. The influence of the gas pressure and standoff distance on the copper content and coating thickness are evaluated. The coating build-up with a high copper content and thickness is highly dependent on the kinetic energy of particles; enhanced by high gas pressure and short stand-off distance.

Heat Dissipation Beyond 1 kW/cm2 With Low Pressure Drop and High Heat Transfer Coefficient for Flow Boiling Using Open Microchannels With Tapered Manifold

2016 ◽  
Author(s):  
Ankit Kalani ◽  
Satish G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Dissipation ◽  
Flow Boiling ◽  
Low Pressure ◽  
High Heat ◽  
High Heat Transfer ◽  
High Heat Transfer Coefficient

Heat dissipation beyond 1 kW/cm2 accompanied with high heat transfer coefficient and low pressure drop using water has been a long-standing goal in the flow boiling research directed toward electronic cooling application. In the present work, three approaches are combined to reach this goal: (a) a microchannel with a manifold to increase critical heat flux (CHF) and heat transfer coefficient (HTC), (b) a tapered manifold to reduce the pressure drop, and (c) high flow rates for further enhancing CHF from liquid inertia forces. A CHF of 1.07 kW/cm2 was achieved with a heat transfer coefficient of 295 kW/m2°C with a pressure drop of 30 kPa. Effect of flow rate on CHF and HTC is investigated. High speed visualization to understand the underlying bubble dynamics responsible for low pressure drop and high CHF is also presented.

Fabrication of Miniature CMOS Image Sensor Using Novel Glass Cover Chip Packaging Technique

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Chuen-Ching Wang ◽  
Yao-Ting Ye ◽  
Jing-Fung Lin
Keyword(s):  
Heat Dissipation ◽  
Performance Indicator ◽  
Glass Plate ◽  
Adhesive Force ◽  
Image Sensor ◽  
Cover Plate ◽  
Adhesive Film ◽  
Glass Cover ◽  
Cmos Image Sensors ◽  
Packaging Technique

This study develops a novel glass cover chip (GCC) technique for the packaging of CMOS image sensors (CIS), in which the glass cover plate is attached directly to the chip using a nonconductive adhesive film. Taking the adhesive force between the glass plate and the chip as a performance indicator, a series of Taguchi trials are performed to establish the optimal GCC processing conditions. The experimental results confirm the feasibility of the proposed packaging technique and indicate a volume reduction of 59.47% compared with the traditional CIS package. Furthermore, the simulation results reveal that the heat dissipation efficiency of the proposed CIS package exceeds that of the traditional package by 245%.

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