Pressure-Assisted Sintering of Buried Thick Film Resistors in LTCC

2015 ◽  
Vol 2015 (CICMT) ◽  
pp. 000239-000244
Author(s):  
Andreas Heunisch ◽  
Victor de Seauve ◽  
Torsten Rabe
Keyword(s):  
Thick Film ◽  
Electrical Resistance ◽  
Particle Distribution ◽  
Laser Diffraction ◽  
The Other ◽  
Sintering Process ◽  
Sheet Resistivity ◽  
Green Tape ◽  
Small Fluctuation ◽  
Conductive Phase

In this work, the effect of the pressure-assisted sintering process on buried thick film resistors integrated in LTCC multilayer has been studied. Four commercial resistor pastes with sheet resistivities between 10 kΩ and 10 MΩ/cm were analyzed. First they were characterized by SEM/EDX, XRD and Laser diffraction to determine composition and particle distribution. The pastes consist of isolating particles and of Ruthenium based particles that are supposed to build the conductive phase. The pastes were screen printed on LTCC green tape (DP 951) and buried in four layer laminates. Sintering was done in two ways, pressureless (PLS) and also pressure-assisted (PAS). The pressureless sintered resistors showed electrical resistance values roughly in the range of the nominal sheet resistivity and only relatively small fluctuation within one sample. The PAS samples on the other hand showed significantly higher resistances and larger deviations. The microstructure of the sintered resistors was again investigated by SEM and XRD. It seems that the resistivity is determined by the ratio of the two Ruthenium phases RuO2 and Pb2Ru2O6.5, where RuO2 has the higher conductivity. Buried resistors cannot be trimmed by a laser to adjust the resistance. But we discovered that a refiring step will reduce and normalize the resistivity of the PAS resistors significantly.

Thick Film Metallization of AlN by Reactive Binders

2010 ◽  
Vol 105-106 ◽  
pp. 301-304
Author(s):  
Ren Zhong Shuai ◽  
Hong Lei Zheng ◽  
De An Yang
Keyword(s):  
Thick Film ◽  
Adhesion Strength ◽  
Electrical Resistance ◽  
Castor Oil ◽  
Ethyl Cellulose ◽  
Sintering Process ◽  
Film Properties ◽  
Organic Vehicle ◽  
Potential Applications ◽  
Paste Viscosity

The thick-film metallization of AlN has received considerable attention because of its potential applications in electronic packaging. Here we reported on the thick film metallization of AlN by reactive binders. The metallization paste of Ag was prepared with organic vehicle of castor oil, ethyl cellulose and beta-terpineol and reactive binders of TiB2 and Co3O4. The control of the paste viscosity was discussed by changing the dispersant content. Meanwhile effects of the components and sintering process on the thick film properties were investigated. The properties of metallization film were analyzed with XRD, SEM and electrical test. The adhesion strength and the electrical resistance of the film were 12.7MPa and 5.3mΩ/□ respectively when the paste composition of Ag, TiB2, Co3O4 and the organic vehicle was 72.8%, 1.5%, 0.7% and 25% and the film was sintered in air at 850°C for 15 minutes.

scholarly journals Design Concepts for NiTiNOL Wires to Function as a Sensor

2021 ◽  
Author(s):  
D. Josephine Selvarani Ruth
Keyword(s):  
Shape Memory Alloy ◽  
Electrical Resistance ◽  
Nickel Titanium ◽  
The Other ◽  
Sensing Element ◽  
Proper Selection ◽  
Design Concepts ◽  
Mechanical Element ◽  
Selection Of ◽  
Inverse Hysteresis

AbstractNickel Titanium Naval Ordinance Laboratory (NiTiNOL) is widely called as a shape memory alloy (SMA), a class of nonlinear smart material inherited with the functionally programmed property of varying electrical resistance during the transformation enabling to be positioned as a sensing element. The major challenge to instrument the SMA wires is to suppress the wires’ nonlinearity by proper selection of two important factors. The first factor is influenced by the mechanical biasing element and the other is to identify the sensing current for the sensing device (SMA wires + biasing). This paper focuses on developing SMA wires for sensing in different orientation types and configurations by removing the non-linearity in the system’s output by introducing inverse hysteresis to the wires through the passive mechanical element.

Environmental tests of embedded thin- and thick-film resistors in comparison to chip resistors

Circuit World ◽  
2014 ◽  
Vol 40 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Wojciech Steplewski ◽  
Andrzej Dziedzic ◽  
Janusz Borecki ◽  
Grazyna Koziol ◽  
Tomasz Serzysko
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Electrical Resistance ◽  
Printed Circuit Boards ◽  
Base Material ◽  
Forming Process ◽  
Content Type ◽  
Thin Film Resistors ◽  
Embedded Resistors ◽  
The Impact

Purpose – The purpose of this paper is to investigate the influence of parameters of embedded resistive elements manufacturing process as well as the influence of environmental factors on their electrical resistance. The investigations were made in comparison to the similar constructions of discrete chip resistors assembled to standard printed circuit boards (PCBs). Design/methodology/approach – The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon-silver inks as well as chip resistors in 0402 and 0603 packages. The polymer thick-film resistive films were screen-printed on the several types finishing materials of contact terminations such as copper, silver, and gold. To determine the sensitivity of embedded resistors versus standard assembled chip resistors on environmental exposure, the climatic chamber was used. The measurements of resistance were carried out periodically during the tests, and after the exposure cycles. Findings – The results show that the change of electrical resistance of embedded resistors, in dependence of construction and base material, is different and mainly not exceed the range of 3 per cent. The achieved results in reference to thin-film resistors are comparable with results for standard chip resistors. However, the results that were obtained for thick-film resistors with Ag and Ni/Au contacts are similar. It was not found the big differences between resistors with and without conformal coating. Research limitations/implications – The studies show that embedded resistors can be used interchangeably with chip resistors. It allows to save the area on the surface of PCB, occupied by these passive elements, for assembly of active elements (ICs) and thus enable to miniaturization of electronic devices. But embedding of passive elements into PCB requires to tackle the effect of each forming process steps on the operational properties. Originality/value – The technique of passive elements embedding into PCB is generally known; however, there are no detailed reports on the impact of individual process steps and environmental conditions on the stability of their electrical resistance. The studies allow to understand the importance of each factor process and the mechanisms of operational properties changes depending on the used materials.

Morphologies of Silver Films Fabricated by Thermal Decomposition of Silver Behenate

2006 ◽  
Vol 11-12 ◽  
pp. 481-484
Author(s):  
Xian Hao Liu ◽  
Shu Xia Lu ◽  
Wei Liang Cao ◽  
Jing Chang Zhang
Keyword(s):  
Thermal Decomposition ◽  
Thick Film ◽  
Silver Film ◽  
The Other ◽  
Silver Particles ◽  
High Concentration ◽  
Decomposition Products ◽  
Silver Films ◽  
Triangular Shape ◽  
Thermal Decomposition Products

Various morphologies of silver films fabricated by the thermal decomposition of silver behenate have been studied. The morphological structures of silver behenate films at different heating temperatures are characterized by using SEM, IR and XRD. It is found that, while heating the silver behenate films, the formed silver particles are stabilized by the other thermal decomposition products in the range of 193°C∼320°C. The influence of silver behenate concentration in organic solvent on the formation and packing density of as-fabricated silver films by thermal treatment on the silver behenate films at 500°C has been studied. The results show that the silver film fabricated by a millimolar solution of silver behenate possesses a silver monolayer; the silver thick film can be formed at high concentration, and interestingly, silver particles with regular triangular or truncated triangular shape in the silver thick film are also obtained.

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.

scholarly journals Processing Considerations of Thick Film Devices With Multilayered Resistors

1981 ◽  
Vol 9 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Nobuyuki Sugishita ◽  
Akira Ikegami ◽  
Tsuneo Endo
Keyword(s):  
Thick Film ◽  
Thermal Storage ◽  
Resistivity Change ◽  
Sheet Resistivity ◽  
Dielectric Layers ◽  
The Stability ◽  
Film Dielectric

The results of a study into the fabrication of thick film multilayer devices which include resistors on and under the thick film dielectric layers are presented. Although the resistive values of the resistors under the dielectric change in the succeeding firing processes are influenced by the geometry of the resistors, the ratio of the resistivity change in resistors fabricated with the same sheet resistivity pastes and the same geometry is almost the same. The TCR of the resistors under dielectric layers is influenced mainly by the multi-firing processes. The resistive values and TCR of the resistors on dielectric layers are relatively uninfluenced by the dielectric. The stability of these resistors including trimmed ones under long-term thermal storage at 150℃ is compared with that of resistors on alumina substrates.

Reply to ‘Comment on “Collective effects in bremsstrahlung in plasmas” ’

1998 ◽  
Vol 60 (2) ◽  
pp. 447-448 ◽  
Author(s):  
V. N. TSYTOVICH ◽  
R. BINGHAM ◽  
U. de ANGELIS ◽  
A. FORLANI
Keyword(s):  
Particle Distribution ◽  
Thermal Plasmas ◽  
Solar Interior ◽  
The Other ◽  
Standard Approach ◽  
Collective Effects ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem ◽  
Electron Bremsstrahlung ◽  
Non Equilibrium

We reply here to a criticism of our paper (Tsytovich et al. 1996) by Iglesias (1997).In our paper we present a very general formulation of collective effects in bremsstrahlung that is valid for any non-equilibrium non-Maxwellian particle distribution. This result is given in (2.20) early in the paper. The standard treatments of bremsstrahlung found in books like Bekefi (1966) are only for thermal plasmas, where the fluctuation–dissipation theorem is valid. Note that the fluctuation–dissipation theorem cannot be used for non-thermal or non-dipole fields, and in this respect the method we use is more general. Our method is the more complex of the approaches used, but, as stated, it can handle situations that cannot be treated by the standard approach. Our main result is the formula (2.20), which is valid for any non-equilibrium non-Maxwellian particle distribution, and which cannot be found anywhere else in the literature. Furthermore, we find new qualitative effects indicating that the ion–ion bremsstrahlung (which is always neglected in the literature) is not small in the case where the collective effects are taken into account, and is in fact, for certain frequencies, of the order of the electron–electron bremsstrahlung. The other qualitatively new result is that, where collective effects are important, the electron–electron bremsstrahlung is not of the order v2Te/c2, as it is for the case in the absence of collective effects, but of the order ω2pe/ω2 times less – which, for example in the solar interior, where ω2pe/ω2 is of the order of v2Te/c2, is then of the order of v4Te/c4.

Sintering Behavior of the Powder Injection Molded Nanocrystalline Fe-50wt%Ni

2004 ◽  
Vol 449-452 ◽  
pp. 1141-1144 ◽  
Author(s):  
H.Y. Nam ◽  
S.K. Kwon ◽  
Young Soo Kang ◽  
Jai Sung Lee
Keyword(s):  
Particle Distribution ◽  
Powder Injection ◽  
Sintering Behavior ◽  
Impurity Effect ◽  
Microstructure Development ◽  
Sintering Process ◽  
Nano Powder ◽  
Homogeneous Particle ◽  
Injection Molded ◽  
Binder Material

Sintering process of powder injection molded (PIMed) Fe-50wt%Ni nanoalloyed powder was investigated in association with microstructure development and residual impurity effect. Compared to conventional powder metallurgical (PM) processed Fe-Ni nanoalloy powder, the PIM compact showed a homogeneous and uniform densification behavior. This is owing to more homogeneous particle distribution in the PIM resulting from preparation of feedstock which was fabricated by mixing of nano powder with thermoplastic binder. Residual impurities originating from the binder material did not have any apparent influences on sintering behavior. Conclusively, Fe-50wt%Ni nanoalloy powder is effectively applicable to the PIM parts.

Relation between air water potential and cambial electrical resistance of balsam fir and white spruce after budbreak

1987 ◽  
Vol 17 (2) ◽  
pp. 105-108 ◽  
Author(s):  
Robert R. Gagnon ◽  
Eric Bauce ◽  
Marius Pineau
Keyword(s):  
Relative Humidity ◽  
Water Potential ◽  
Correlation Coefficient ◽  
Electrical Resistance ◽  
White Spruce ◽  
The Other ◽  
Balsam Fir ◽  
Simultaneous Measurements ◽  
Electrical Resistance Measurements ◽  
Made In

Cambial electrical resistance in 10 balsam fir (Abiesbalsamea (L.) Mill.) and 10 white spruce (Piceaglauca (Moench) Voss) trees in Québec was measured 42 times during July and August 1985. Simultaneous measurements of relative humidity and temperature were also taken so that water potential in air (ψa) could be determined. In both species, cambial electrical resistance, corrected to a constant temperature of 15 °C (CERCOR), was negatively correlated with ψa. On the other hand, 10 measurements on 14 balsam fir trees that had been severely defoliated by the spruce budworm (Choristoneurafumiferana (Clem.)) in 1983 and 1984, and 12 measurements on 14 protected trees showed that the correlation was stronger for sprayed trees than for those that had been defoliated. We propose that the correlation coefficient between cercor and ψa may be a useful index of tree vigor. However, in situations where plots can be visited only once during the season, cambial electrical resistance measurements should be made in the morning when the relative humidity is high.

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