Query: copper firing mlcc

Candidate papers:

abstract: Recent trends and progresses in power electronics rely on fast, miniaturized, high current and high temperature switching semiconductors. However, in electronics system design, passive components technologies, in particular capacitors, limit their full exploitation. The goal of the present paper is, firstly, to analyse the capacitor technologies, in particular ceramic technologies for the limits set by high current, high voltages, high temperatures, high frequencies, and by cost items. Secondly, for each of the identified limits, to define the tools and technologies that are capable to overcome it. The new technologies include a new PLZT based antiferroelectric ceramic material with high switching field, copper inner electrode for the multilayer construction, firing in reducing atmosphere, applying a sputter method for the outer connecting electrode combined with silver sintering of a flexible termination or of a pressfit connector. The third goal is to show how the new technologies are applied such that
author_names: Guenter Engel
title: Material Requirements for Power and High Temperature Multilayer Ceramic Capacitors (MLCC)
year: 2015

abstract: Microstructure of termination of a base metal electrode multilayer ceramic capacitor (BME MLCC) using copper nickel bimetallic powder as electrode material was investigated. Thick film paste containing nonagglomerated monodispersed copper nickel bimetallic powder was applied in preparing the termination electrode of a BME MLCC. Influence of an inorganic binder on the microstructure of the termination of BME MLCC was studied. The distribution of metallic copper on the surface of glass bubbles in termination was investigated by energy dispersive X ray. A scanning electron microscope and a polarized light microscope were applied to discuss the microstructure of thick film. The results show that suitable binder and firing temperature result in the excellent connection between internal and termination electrode, as well as one between termination electrode and green chip. The BME MLCCs with a dense surface of end termination, high adhesion, and qualified electrical behavior were obtained. The rough interface from interfacial reaction between glass and chip gives high adhesion
author_names: Wu Songping
title: Termination of BME MLCC Using Copper Nickel Bimetallic Powder as Electrode Material
venue: IEEE Transactions on Components and Packaging Technologies
year: 2006

abstract: The copper paste for termination electrode of BME MLCC is composed of organic vehicle,glass frit,copper powder and others.The termination electrodes are formed after dipping,drying and terminal firing.Results of experiments indicate that copper paste for BME MLCC has high adhesion and low DF,and is well fit for BME MLCC.
author_names: Jin Fu-zhen
title: Research of Copper Termination Paste for BME MLCC
year: 2006

abstract: Conventional copper powder used to form terminations of MLCC generally contains large flakes with high aspect ratios and large agglomerate spherical particles. The use of agglomerate powder and large flakes results in low dry film density, and thus a thicker film. In our research, we focused on highly dispersed, uniform, and fine flakes and powder that did not contain coarse particles, and examined the paste characteristics and their effect on firing conditions. We found that a smaller particle size would increase the thixotropic value and result in an earlier start to firing. We also discovered that the agglomerate condition of powder had a significant influence on the rheology of the paste. A higher degree of agglomeration would result in higher viscosity and a higher thixotropic value, but would not have a major effect on the firing condition.
author_names: Takahiko Sakaue

Katsuhiko Yoshimaru
title: Copper Powder for Termination Electrode in MLCC
year: 2003

abstract: Abstract In this paper, non agglomerated monodispersed ultra fine copper metallic powders have been synthesized with chemical reduction method. Fine lead free glass powders were also prepared by solid synthesis process. Thick film paste prepared by above mentioned copper metallic powders and lead free glass powders was applied as conductive paste of MLCC. Mixture of glass and zinc oxide give the thick film a high adhesion strength which is attributed to the rough interface from interfacial reaction between glass and chip, and a good densification. Diffusion of metal between copper thick film and nickel thick film is clear. Ni Cu solid solution appears under high temperature firing.
author_names: Songping Wu
title: Preparation of ultra fine copper powder and its lead free conductive thick film
year: 2007

abstract: Direct bonded copper (DBC) also called the gas metal eutectic bonding method, is an important substrate material commonly used for thermal and electrical management in power modules. Developed almost 40 years ago by General Electric, there is wide use of this structure when there is a need of a substrate with high current carrying and high thermal conductive abilities. The components of DBC are a ceramic (usually Aluminum Oxide (Al2O3, also called "alumina" and a bonded piece of copper on one or both sides. This copper is strongly bonded to the alumina, giving strong adhesion and combining benefits from both materials. This paper will give a summary of DBC technology and will discuss the role that furnace temperature and atmosphere perform during processing. Introduction The development of DBC has pushed boundaries of power electronic applications. It is used in such products as concentrated photovoltaics and semiconductor modules for automotive applications [1] The value of DBC comes from its high thermal conductivity due to copper and its low coefficient of thermal expansion as a result of ceramic. The need for low thermal expansion is so that solder on silicon semiconductors won't be damaged with heat cycling. For DBC ceramics, alumina (Al2O3) is commonly used, but other ceramics such as aluminum nitride (AlN) or Beryllium Oxide (BeO) are also utilized in bonding. Alumina is preferred because of its low cost and efficiency compared to these other ceramics, and DBC is chosen over other bonding processes because there is no need for intermediary layers in the process. According to Burgess et al. Al. MgO, SiO2, and CaO are intermediary layers located at the grain boundaries of the ceramic. This layer penetrates into the porous layer of the metal at sintering temperatures and locks the metal into the ceramic. DBC is preferred because intermediary layers often have problems with current flows at the metal ceramic interface and are less corrosion resistant, leading to early failure. DBC begins with layering of copper onto alumina as seen in Figure 1. The contact interface between the copper and the alumina is the most important area of processing. Copper exhibits a wetting behavior on alumina that covers the area of contact during firing. With a temperature range between 1065o C and 1083o C, interface adhesion occurs. With research and developments in DBC technology, production is possible on a larger scale using equipment such as the belt furnace. Controlling furnace conditions is important in reaching the high eutectic temperature that is needed to begin the bonding process while staying below the melt temperature of copper. Specific controls of the furnace atmosphere are needed as well during processing.
title: Influence of Firing Temperature and Atmospheric Conditions on the Processing of Directly Bonded Copper DBC
year: 2017

abstract: .iii LIST OF FIGURES .vi LIST OF TABLES .xii ACKNOWLEDGMENTS .xiii CHAPTER 1 GENERAL INTRODUCTION .1 1.1 Applications: Multilayer Ceramic Capacitors (MLCCs) .1 1.2 Background: Perovskite Structure. .3 1.3 Background: Ferroelectricity .5 1.3.1 Relaxor Ferroelectrics .6 1.4 (1 x)BaTiO3 xBi(M)O3 Dielectrics .7 1.5 Cofiring BaTiO3 Bi(Zn1/2Ti1/2)O3 with Electrodes .9 1.5.1 Proposed Solution to Thermodynamic Challenges .10 1.5.2 Additional Challenge: Lowering the Dielectric Sintering Temperature .12 1.6 Thesis Organization .13 CHAPTER 2 CURRENT UNDERSTANDING OF STRUCTUREPROCESSING PROPERTY RELATIONSHIPS IN BaTiO3 Bi(M)O3 DIELECTRICS .16 2.
author_names: Michaela A Beuerlein
title: Phase Formation, Microstructure Development, and Copper Co Firing of Barium Titanate Bismuth Zinc Titanate and Related Dielectrics
year: 2017

abstract: Small arms firing ranges are an important source of metal contaminants in the ecosystems located near these facilities, owing to the constant fall and alteration of the ammunition remnants on the soil, particularly in nearby berms. The objectives of this study were to analyse the pollution of chromium (Cr) copper (Cu) nickel (Ni) lead (Pb) and zinc (Zn) in rifle/pistol shooting range soils, to estimate their availability and to evaluate the influence of the ammunition used. The concentrations of Pb, Zn, Cu, Cr and Ni range from 55 to 6*309, 34 to 264, 19 to 98, 40 to 79 and 11 to 33 mg kg 1, respectively. The moderate acidity and organic matter content favour the availability of Pb, followed by Cu Zn Ni Cr. The values of different contamination indexes (Igeo, pollution index and integrated pollution index) suggest that Pb soil contamination is moderate to heavy, especially in the berm area and moderate for Cu and Zn. Lead ammunition is the main source of pollution, but another one was identified owing to the concentrations of Fe, Cr and Ni detected. Further studies are needed to verify their long term potential adverse effects. Copyright (c) 2016 John Wiley Sons, Ltd.
author_names: Andres Rodriguez-Seijo

Maria C Alfaya

Maria Luisa Andrade

Flora A Vega
title: Copper, Chromium, Nickel, Lead and Zinc Levels and Pollution Degree in Firing Range Soils
year: 2016

abstract: Abstract The influence of superficial phosphorus rich layers during the metallization firing treatment on carrier recombination and trapping in copper contaminated multicrystalline silicon was investigated. Copper contaminated wafers experienced firing steps with and without phosphorus rich layers. The samples fired without phosphorus emitters feature higher bulk carrier lifetimes, but also a stronger sensitivity to the copper related light induced degradation (LID) which was activated by the firing treatment. This last behavior could be used to identify the dominant LID mechanism (boron oxygen related or copper related) in multicrystalline wafers. In addition, only the samples fired without the phosphorus emitters are subjected to trapping effects, probably involving copper atoms initially precipitated. Copper precipitates are virulent recombination centers whereas the electrical activity of interstitial copper is benign. Therefore these experimental results suggest that on the one hand the wafers fired with the phosphorus rich layers contain lower interstitial copper concentrations. On the other hand they would feature higher densities of copper precipitates and/or larger copper precipitates.
author_names: Sebastien Dubois

Tleuzhan Turmagambetov

Jean Paul Garandet

Helene Lignier

Nicolas Enjalbert
title: Influence of the solar cells metallization firing treatment on carrier recombination and trapping in copper contaminated multicrystalline silicon: new insights into the role of the phosphorus rich layers
year: 2016

abstract: To provide a method for firing a copper paste, which improves sinterability of copper particles for the purpose of forming a copper wiring line that is decreased in the electrical conductivity. A method for firing a copper paste, which comprises: an application step wherein a copper paste is applied over a substrate; a first heating step wherein the substrate is heated in a nitrogen gas atmosphere containing from 500 ppm to 2,000 ppm (inclusive) of an oxidizing gas in terms of volume ratio after the application step, thereby oxidizing and sintering copper particles in the copper paste; and a second heating step wherein the substrate is heated in a nitrogen gas atmosphere containing 1% or more of a reducing gas in terms of volume ratio after the first heating step, thereby reducing the oxidized and sintered copper oxide.
title: Method for firing copper paste
year: 2015