Electrical Performance of Cofired Alumina Substrates at High Temperatures

2013 ◽  
Vol 10 (3) ◽  
pp. 89-94 ◽  
Author(s):  
Liang-Yu Chen
Keyword(s):  
Dielectric Constant ◽  
High Temperature ◽  
Ac Conductivity ◽  
Large Scale ◽  
Dissipation Factor ◽  
Electrical Performance ◽  
Prototype System ◽  
Polycrystalline Aluminum ◽  
Polycrystalline Alumina ◽  
Dielectric Performance

A 96% polycrystalline alumina (Al2O3) based prototype packaging system with Au thick-film metallization successfully facilitated long term testing of high temperature SiC electronic devices for over 10,000 h at 500°C previously. However, the 96% Al2O3 chip-level packages of this prototype system were not fabricated via a commercial cofire process, which would be more suitable for large scale commercial production. The cofired alumina materials adopted by the packaging industry today usually contain several percent of glass constituents to allow cofiring processes at temperatures usually lower than the regular sintering temperature for alumina. In order to answer the question of whether cofired alumina substrates can provide a reasonable high temperature electrical performance comparable to regular 96% alumina sintered at 1700°C, this paper reports on the dielectric performance of a selected high temperature cofired ceramic (HTCC) alumina substrate and a low temperature cofired ceramic (LTCC) alumina (polycrystalline aluminum oxides with glass constituents) substrate from room temperature to 550°C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. Parallel-plate capacitive devices with dielectrics of these cofired alumina and precious metal electrodes were used for measurement of the dielectric properties of the cofired alumina materials in the temperature and frequency ranges. The capacitance and AC parallel conductance of these capacitive devices were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of selected LTCC and HTCC cofired alumina substrates are presented and compared with those of 96% alumina. Metallization schemes for cofired alumina for high temperature applications are discussed to address the packaging needs for low-power 500°C SiC electronics.

Electrical Performance of Co-Fired Alumina Substrates at High Temperatures

2012 ◽  
Vol 2012 (HITEC) ◽  
pp. 000173-000178 ◽  
Author(s):  
Liang-Yu Chen
Keyword(s):  
Dielectric Constant ◽  
High Temperature ◽  
Ac Conductivity ◽  
Large Scale ◽  
Electrical Performance ◽  
Firing Process ◽  
Prototype System ◽  
Polycrystalline Aluminum ◽  
Polycrystalline Alumina ◽  
Dielectric Performance

A 96% polycrystalline alumina (Al2O3) based prototype packaging system with Au thick-film metallization successfully facilitated long term testing of high temperature SiC electronic devices for over 10,000 hours at 500°C previously. However, the 96% Al2O3 chip-level packages of this prototype system were not fabricated via a commercial co-fire process which is more suitable for large scale commercial production. The co-fired alumina materials adopted by the packaging industry today usually contain several percent of glass constituents to provide better adhesion and sealing at interfaces formed during a co-firing process at temperatures usually lower than the regular sintering temperature for alumina. In order to answer the question if co-fired alumina substrates can provide reasonable high temperature electrical performance comparable to those of regular 96% alumina sintered at 1700°C, this paper reports on the dielectric performance of a selected high temperature co-fired ceramic (HTCC) alumina substrate and a low temperature co-fired ceramic (LTCC) alumina (polycrystalline aluminum oxides with glass constituents) substrate from room temperature to 550°C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. Parallel-plate capacitive devices with dielectrics of these co-fired alumina and precious metal electrodes were used for measurement of the dielectric properties of the co-fired alumina materials in the temperature and frequency ranges. The capacitance and AC parallel conductance of these capacitive devices were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of selected LTCC and HTCC co-fired alumina substrates are presented and compared to those of 96% alumina. Metallization schemes for co-fired alumina for high temperature applications are discussed to address packaging needs for low power 500°C SiC electronics.

scholarly journals Dielectric Performance of a High Purity HTCC Alumina at High Temperatures - A Comparison Study with other Polycrystalline Alumina

2014 ◽  
Vol 2014 (HITEC) ◽  
pp. 000271-000277 ◽  
Author(s):  
Liang-Yu Chen
Keyword(s):  
Dielectric Constant ◽  
High Temperature ◽  
High Temperatures ◽  
High Purity ◽  
Ac Conductivity ◽  
Dissipation Factor ◽  
Alumina Substrate ◽  
Raw Material ◽  
Polycrystalline Alumina ◽  
Dielectric Performance

A very high purity (99.99+%) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this alumina material for co-firing processing. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96% polycrystalline alumina (96% Al2O3), where 96% alumina was used as the benchmark. A prototype packaging system based on regular 96% alumina with Au thick-film metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500°C. In order to evaluate this new high purity HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96% alumina and a previously tested LTCC alumina from room temperature to 550°C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96% alumina and a selected LTCC alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.

Electrical Performance of a 32-I/O HTCC Alumina Package for High-Temperature Microelectronics

2017 ◽  
Vol 14 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Liang-Yu Chen ◽  
Philip G. Neudeck ◽  
David J. Spry ◽  
Glenn M. Beheim ◽  
Gary W. Hunter
Keyword(s):  
High Temperature ◽  
Integrated Circuits ◽  
Parasitic Capacitance ◽  
Circuit Board ◽  
Electrical Performance ◽  
Packaging System ◽  
Dielectric Performance ◽  
Temperature Ranges ◽  
Parallel Conductance ◽  
Potential Use

A high-temperature cofired ceramic (HTCC) alumina material was previously electrically tested at temperatures up to 550°C and demonstrated improved dielectric performance at high temperatures compared with the 96% alumina substrate that we used before, suggesting its potential use for high-temperature packaging applications. This article introduces a prototype 32-input/output (I/O) HTCC alumina package with platinum conductor for 500°C low-power SiC-integrated circuits. The design and electrical performance of this package, including parasitic capacitance and parallel conductance of neighboring I/Os from 100 Hz to 1 MHz in a temperature range from room temperature to 550°C, are discussed in detail. The parasitic capacitance and parallel conductance of neighboring I/Os of this package in the entire frequency and temperature ranges measured do not exceed 1.5 pF and 0.05 μS, respectively. SiC-integrated circuits using this package and a compatible alumina circuit board have been successfully tested at 500°C for more than 3,736 h continuously, and at 700°C for more than 140 h. Some test examples of SiC-integrated circuits with this packaging system are presented.

scholarly journals Electrical Performance of a High Temperature 32-I/O HTCC Alumina Package

2016 ◽  
Vol 2016 (HiTEC) ◽  
pp. 000066-000072 ◽  
Author(s):  
Liang-Yu Chen ◽  
Philip G. Neudeck ◽  
David J. Spry ◽  
Glenn M. Beheim ◽  
Gary W. Hunter
Keyword(s):  
High Temperature ◽  
Integrated Circuits ◽  
Printed Circuit Board ◽  
Parasitic Capacitance ◽  
Circuit Board ◽  
Electrical Performance ◽  
Operational Testing ◽  
Dielectric Performance ◽  
Temperature Ranges ◽  
Parallel Conductance

Abstract A high temperature co-fired ceramic (HTCC) alumina material was previously electrically tested at temperatures up to 550 °C, and demonstrated improved dielectric performance at high temperatures compared with the 96% alumina substrate that we used before, suggesting its potential use for high temperature packaging applications. This paper introduces a prototype 32-I/O (input/output) HTCC alumina package with platinum conductor for 500 °C low-power silicon carbide (SiC) integrated circuits. The design and electrical performance of this package including parasitic capacitance and parallel conductance of neighboring I/Os from 100 Hz to 1 MHz in a temperature range from room temperature to 550 °C are discussed in detail. The parasitic capacitance and parallel conductance of this package in the entire frequency and temperature ranges measured does not exceed 1.5 pF and 0.05 μS, respectively. SiC integrated circuits using this package and compatible printed circuit board have been successfully tested at 500 °C for over 3736 hours continuously, and at 700 °C for over 140 hours. Some test examples of SiC integrated circuits with this packaging system are presented. This package is the key to prolonged T ≥ 500 °C operational testing of the new generation of SiC high temperature integrated circuits and other devices currently under development at NASA Glenn Research Center.

Dielectric Properties and Thermal Conductivity of Poly(vinylidene fluoride)-Based Composites with Graphite Nanosheet and Nickel Particle

2019 ◽  
Vol 19 (6) ◽  
pp. 3591-3596 ◽  
Author(s):  
Lirong Wu ◽  
Dandan Yang
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Ac Conductivity ◽  
Vinylidene Fluoride ◽  
Filler Loading ◽  
Graphite Nanosheet ◽  
Dielectric Performance ◽  
Poly Vinylidene Fluoride

The nickel (Ni) particles and graphite nanosheet (GNS) filled poly(vinylidene fluoride) (PVDF) composites were prepared by solution blending and hot-press processing in the magnetic field. The influence of Ni particles and GNS fillers for the structure, morphology, AC conductivity, dielectric properties and thermal conductivity of composites was investigated. The results showed that the β-phase crystals of PVDF matrix was increased obviously. The AC conductivity, dielectric constant and dielectric loss of PVDF/Ni/GNS composite reached to 10−9 s/cm, 62 and 0.39 when the filler loading was 11 wt.% at 102 Hz, respectively. At the ratio of 15 wt.% filler, the AC conductivity of PVDF/Ni/GNS composite was vastly improved to 10−6 s/cm, however, the dielectric constant increased to ~80 and dielectric loss was over 600 at 102 Hz. By comparing the dielectric performance of PVDF/Ni/GNS, PVDF/Ni and PVDF/GNS composites, it is found that the parallel arrangement of the filler conduces to improve the dielectric properties of the composites. Furthermore, the thermal conductivity of PVDF/Ni/GNS composites increased with the increase of Ni and GNS contents and the value raised to over 0.5 W/mK when filler loading was 15 wt.%.

Thick Film Capacitors with Variable Tc on Cu Foils

2008 ◽  
Vol 1075 ◽  
Author(s):  
Byeong Kon Kim ◽  
Dong Joo Shin ◽  
Jun Kwang Song ◽  
Yong Soo Cho
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Low Temperature ◽  
Thick Film ◽  
Dissipation Factor ◽  
Embedded Capacitors ◽  
High K ◽  
Dielectric Performance ◽  
Cu Foil ◽  
High K Dielectric

ABSTRACTHigh k dielectric thick films, consisting of BaTiO3, a low softening glass and fluoride compounds, were studied to apply them as potential low temperature N2-fireable capacitors on commercially-available Cu foils. Different additive combinations of LiF, ZnF2 and BaF2 were specifically compared in terms of dielectric constant, dielectric loss and Curie temperature (Tc) for the purpose of optimizing dielectric performance. The thick film consisting of 95BaTiO3-1.5LiF-1.5ZnF2-2 bismuth borosilicate glass exhibited the best performance, i.e., a dielectric constant of 2,382 and a dissipation factor of 0.021 at Tc of 27°C at the firing temperature of 950°C. This result can be regarded as one of the best performance, compared to literature reported on embedded capacitors in Cu-PCB applications. No apparent Cu-diffusion was detected across the Cu-thick film-Cu foil structure.

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

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