A Low Firing Temperature Copper Conductor for use on an Aluminum Metal Compatible Dielectric in LED Thermal Substrate Applications

2012 ◽  
Vol 2012 (1) ◽  
pp. 001178-001184 ◽  
Author(s):  
Samson Shahbazi ◽  
Steve Grabey ◽  
Ryan Persons
Keyword(s):  
Thick Film ◽  
Firing Temperature ◽  
Copper Foil ◽  
Performance Testing ◽  
Base Layer ◽  
Reliability Testing ◽  
Metal Base ◽  
Copper Base ◽  
Copper Conductor ◽  
Polymer Dielectric

One of the most important contributing factors in the long life of LEDs (Light Emitting Diode) is keeping them cool, i.e., lowering the junction temperature, which can get as high as 150 °C. One way to accomplish this when building a circuit containing many LED packages is to use a thermal substrate. The majority of High Power/High Brightness (HP/HB) LED thermal circuits manufactured today are based on Metal Core Printed Circuit Board (MCPCB) technology. The MCPCB system consists of a copper foil, polymer dielectric layer and either an aluminum or copper base layer that are laminated together. The process of making MCPCB is a subtractive process, where most of the copper foil is removed. The copper foil is etched to create a circuit layer, the polymer dielectric provides the insulation between the copper foil and the metal base, and the aluminum or copper base provides thermal dissipation. The thick film copper paste discussed in this document is processed using an additive process, like screening printing, where the copper conductor is deposited only in the chosen area. The copper thick film paste is screen printed to create a circuit design on top of a thick film dielectric (insulated area) layer which is also printed on a metal base layer. The selective deposition allows for less material usage, and potentially lower overall cost as well as improved thermal performance with inclusion of thermal vias. This paper discusses the results of a newly developed lead (Pb) and cadmium (Cd) free low firing temperature (580–600°C) copper thick film conductor paste on top of a low temperature firing dielectric paste. This study includes evaluations based on SEM photos, solderability, leach resistance, and initial and long term adhesions using SAC 305 solder and RMA flux. There are many different applications for HP/HB LED circuits, from general lighting to street lighting to automotive lighting and more. All of them have varying degrees of performance testing requirement. To try to cover as much of the reliability testing as possible we have included tests such as thermal aging (150°C), thermal cycling from −50 to+150°C, as well as 85°C/85% RH reliability testing under bias.

scholarly journals Size Effects in Ruthenium-Based Thick-Film Resistors: Rutile vs. Pyrochlore-Based Resistors

1991 ◽  
Vol 14 (3) ◽  
pp. 163-173 ◽  
Author(s):  
M. Prudenziati ◽  
F. Sirotti ◽  
M. Sacchi ◽  
B. Morten ◽  
A. Tombesi ◽  
...  
Keyword(s):  
Size Effect ◽  
Thick Film ◽  
Sheet Resistance ◽  
Firing Temperature ◽  
Size Effects ◽  
Conductive Phase ◽  
Lower Sheet ◽  
Lower Sheet Resistance

The size effect, namely the change of sheet resistance, Rsas a function of resistor length, has been investigated in layers whose conductive phase evolves from Pb-rich (Ru-deficient pyrochlores) to Pb2Ru2O6.5and finally to RuO2by increasing the firing temperature. It is found that Bi diffusion from the terminations is responsible for lower sheet resistance values in shorter resistors whatever the conductive phase is. On the contrary, Ag diffusion is responsible for lower sheet resistance values in shorter resistors only in the case of ruthenate conductive grains while the reverse is observed in RuO2-based layers. Size effect can be suppressed with Pt/Au-based terminations provided that no Bi is contained and with Au-metallorganic-based contact provided that the peak firing temperature is not too high.

Effect of firing temperature on surface morphology of nanosized ferrite-based thick film with linseed oil as organic vehicle

2019 ◽  
Vol 16 (11/12) ◽  
pp. 660
Author(s):  
Intan Helina Hasan ◽  
Mohd Nizar Hamidon ◽  
Muhammad Asnawi Mohd Kusaimi ◽  
Saman Azhari ◽  
Nur Alin Mohd Azhari ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Thick Film ◽  
Firing Temperature ◽  
Linseed Oil ◽  
Organic Vehicle

scholarly journals A Study on Effect of Line Width, Composition and Firing Temperature on the Microstripline Properties

2000 ◽  
Vol 23 (3) ◽  
pp. 163-173 ◽  
Author(s):  
Sunit Rane ◽  
Vijaya Puri
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Line Width ◽  
Firing Temperature ◽  
Thick Films ◽  
Alumina Substrate ◽  
Thin Film Technology ◽  
Binder Composition ◽  
Cu Thin Film ◽  
Ku Band

The transmittance and reflectance of microstriplines of different widths, fabricated by thick film and thin film technology are studied in the X and Ku band (8–18 GHz). The fritless thick film Ag pastes with different binder composition was formulated indigenously and screen-printed the microstriplines on alumina substrate. These microstriplines were compared with the microstriplines made from ESL (USA) pastes and also Cu thin film circuits. The effect of line width, composition and firing temperature on the thick film microstriplines was investigated. The transmittance of all the indigenously prepared Ag thick film paste compared well with microstriplines prepared with ESL pastes. All these thick film pastes gave good transmittance upto 18.0 GHz. The results indicate firing at 700℃ gives best films, and also 18 mil or 20-mil line width is more suitable than conventional 25-mil line width if thick films are used for metallization upto 18.0 GHz.

scholarly journals APPLICABILITY OF COMPOSITE CUTTERS FOR MASHINING SURFACES FORMED BY A COMBINATION OF STRUCTURAL MATERIALS

2017 ◽  
Vol 21 (2) ◽  
pp. 91-98
Author(s):  
E. V. Pavlov ◽  
I. М. Smirnov
Keyword(s):  
High Performance ◽  
Cubic Boron Nitride ◽  
Performance Testing ◽  
Structural Materials ◽  
Polymer Materials ◽  
Base Surface ◽  
Metal Base ◽  
Discontinuous Surface ◽  
Tool Materials ◽  
Intermittent Cutting

The paper states the difficulty of turning of structural elements of items with a combined surface, namely, a metal base surface with inclusions of polymer materials; impossibility to provide the required performance quality using traditional tool materials, especially in the areas of metal and polymer contact is shown. Major technological challenges that should be addressed as a whole while designing turning tools are presented. They are: providing shock-free conditions for digging of the cutting element in a discontinuous surface; achievement of high levels of quality and accuracy of the surface formed by the combination of dissimilar structural materials; damping of oscillations caused by the discontinuous nature of the cutting process. Several designs of turning tools with damping elements suitable for oscillation and vibration damping were reviewed. The nature and extent of the influence of intermittent cutting conditions when damping vibrations and loads on the machining quality levels and tool life were investigated. The main characteristics and features of the considered designs of cutting tools were studied; design and engineering solutions for the implementation of tools with damping properties into the production process were proposed; ways for abatement of vibrations arising in the process of turning of combined surfaces were recommended. Performance testing of new designs of cutters under conditions of intermittent cutting of structurally complex surfaces of machine parts operating under alternating loads showed high performance of super-hard tool materials based on cubic boron nitride. Under damping while turning parts made of HH 40KHN, 12KHN3A steel, the quality of the machining of the seventh quality grade with the index of roughness of the processed surface Ra ≤ 0.63 µm, including surface cutting, which is a combination of several structural materials, was achieved.

Solderable Polymer Thick-film Conductors for Low Temperature Substrates

2018 ◽  
Vol 2018 (1) ◽  
pp. 000310-000316
Author(s):  
Seigi Suh ◽  
Ryan Persons ◽  
Doug Hargrove ◽  
Gregory Berube
Keyword(s):  
Thick Film ◽  
Silver Chloride ◽  
Performance Testing ◽  
Product Line ◽  
Temperature Sensitive ◽  
Wearable Electronics ◽  
Electronic Market ◽  
Medical Monitoring ◽  
Potential Cost ◽  
Flexible Polymer

Abstract For decades, polymer thick-film (PTF) systems have provided a low cost, non-fired option for screen-printing simple electronic circuits. The ability to apply these types of pastes on temperature sensitive substrates such as PET, polycarbonate, polyimide, and other polymers has facilitated a variety of applications, for instance membrane touch-switch keypads, buss bars for touch screens, various types of sensors, and flexible circuitry. Polymer thick-film is also one of the primary technology solutions utilized in the rapidly emerging Printed Electronic market, where flexible, durable materials are paramount to the success of these technologies. One of the largest emerging markets for polymer thick-film is wearable electronics, where engineers are designing “smart fabrics” with active circuitry for medical monitoring, performance enhancement in sports, and personal comfort. Polymer thick-film pastes include silver pastes for conductors, carbon pastes for resistive applications, silver-silver chloride fillers for glucose sensors, and dielectric pastes. The major challenge with PTF silver conductors is that they are not conducive to soldering. This hinders the ability to attach components, leads, dies, wires, or other features to the prints. As copper is solderable, one possible solution would be a copper polymer thick-film metallization; however they start oxidizing at the typical paste curing temperatures, 110 – 130°C, rendering them unsuitable for the vast majority of conductive applications. In order to meet these challenges, Heraeus has developed a new line of solderable polymer thick-film conductors based on a high-performance silver-coated copper conductive filler. These metallizations are solderable, resistant to solder leaching, and result in sheet resistivities approaching that of pure silver polymer conductors. The prints do not degrade in performance when cured at temperatures as high as 200°C. The new product line was formulated to accept different types of solders, especially traditional SAC-305, which provides a complete matched solution for designers. The new metallization opens up new applications given its ability to print polymer circuitry on a variety of substrates including aluminum, steel, FR4, Kapton, Mylar, and glass. The technology also allows for the fabrication of more complex circuitry on these types of substrates, giving circuit designers a powerful new tool in their toolbox in applications such as LED lighting, sensors, and heaters. Finally, these materials may provide a lower-cost option for solderable flexible polymer end terminations for components used in vibration sensitive applications, for instance the automotive industry. In our paper, we will present the properties of the new pastes and printed conductors. Performance testing includes surface resistivity, solderability, solder leach resistance, voiding, and adhesion on two substrates: FR4 and Kapton. Furthermore, we show that the solderable PTF conductor will provide a potential cost- savings over the current technology used on FR4 boards, stamped copper films. By replacing the stamped copper with our solderable PTF conductor, manufacturers will have the advantage of replacing a subtractive process for etching their patterns with an additive, environmentally friendly process, not only saving processing time but eliminating a large, dangerous copper waste stream. Finally, we will summarize the applications that the new technology enables.

Preparation of BiFeO3-BaTiO3 Based Thick Films by Screen Printing

2013 ◽  
Vol 582 ◽  
pp. 55-58 ◽  
Author(s):  
Tomoaki Futakuchi ◽  
Tatsunori Kakuda ◽  
Yuichi Sakai
Keyword(s):  
Thick Film ◽  
Firing Temperature ◽  
Coercive Field ◽  
Screen Printing ◽  
Remanent Polarization ◽  
Ferroelectric Properties ◽  
Thick Films ◽  
Organic Vehicle ◽  
Roll Mill

0.67BiFeO3-0.33BaTiO3thick films were prepared by screen printing pastes prepared by kneading the 0.67BiFeO3-0.33BaTiO3powder in a three-roll mill with an organic vehicle. The thick films were fired with Pt bottom electrodes and ZrO2substrates to investigate the influence of firing temperature. The microstructures and ferroelectric properties of the thick films were examined and compared with the bulk ceramics. A remanent polarization of 32.0 μC/cm2and coercive field of 28 kV/cm were obtained for a thick film with the addition of 0.5 wt% MnO that was fired at 1050 °C.

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