scholarly journals Properties of Porous AlN Multilayered Ceramic Sandwich Substrates

2002 ◽  
Vol 17 (5) ◽  
pp. 1061-1068 ◽  
Author(s):  
F. Y. C. Boey ◽  
A. I. Y. Tok ◽  
Y. Long ◽  
H. Y. Yeong
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Thermal Expansion ◽  
Integrated Circuits ◽  
Mechanical Strength ◽  
Tape Casting ◽  
Boundary Effects ◽  
Dielectric Substrates ◽  
Interface Cracking ◽  
Tape Cast

The development of denser and higher powered integrated circuits has led to a corresponding demand on the performance of dielectric substrates. This paper reports on the fabrication and properties of an AlN multilayered sandwich substrate comprising porous tape-cast layers sandwiched between nonporous layers. Tapes were produced by nonaqueous tape casting, with the porous tapes produced using polymer microspheres as sacrificial molds. Starting from initially Al2O3-rich tapes, the multilayered sandwich substrates were reaction sintered to produce AlN substrates. No interface cracking or delamination was observed in the substrates as a result of the processing. The added porosity resulted in a decrease in the substrate dielectric constant in correspondence to porosity volume. Mechanical strength of the sandwich substrates was improved over that of nonsandwich porous substrates, while substrates having noninterconnected pores showing higher mechanical strength than substrates with connected pores. Substrates with more than 2% porosity showed porosity-dependent thermal conductivity values, while thermal conductivity of substrates with less than 2% porosity was dependent on grain boundary effects. Thermal expansion coefficient of the substrates was unaffected by porosity levels.

Aluminum Nitride fibers from a Thermoplastic Organoaluminum Precursor

1987 ◽  
Vol 108 ◽  
Author(s):  
John D. Bolt ◽  
Fred N. Tebbe
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Thermal Expansion ◽  
High Temperature ◽  
Aluminum Nitride ◽  
Melt Spinning ◽  
Elevated Temperatures ◽  
Fine Particles ◽  
Bulk Ceramic ◽  
Higher Temperature

ABSTRACTA new organoaluminum polymer (EtAINH)n(Et2AlNH2)m·AlEt3 derived from triethylaluminum and ammonia, is thermoplastic at elevated temperatures and a glassy solid at ambient temperature. As a thermoplastic it can be processed in certain shapes, solidified, cured and transformed to dense aluminum nitride with retention of its shape. Aluminum nitride fibers are prepared by melt spinning the polymer, pyrolyzing in ammonia and at high temperature in nitrogen. The AlN microstructure forms as very fine particles at 400–600°C, coarsens at higher temperature, and densifies at 1600–1800 °C into polycrystalline AlN with submicron grains. Mechanical strength, thermal expansion and dielectric constant are consistent with bulk ceramic values. Initial thermal conductivity deduced from composite measurements is 82 W/m°K in fibers containing 0.5 to 1.0 percent oxygen.

scholarly journals Effects of Zr-Cu Alloy Powder on Microstructure and Properties of Cu Matrix Composite with Highly-Aligned Flake Graphite

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5709
Author(s):  
Cunguang Chen ◽  
Qianyue Cui ◽  
Chengwei Yu ◽  
Pei Li ◽  
Weihao Han ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Alloy Powder ◽  
Bending Strength ◽  
Coefficient Of Thermal Expansion ◽  
Tape Casting ◽  
Strain Engineering ◽  
Flake Graphite ◽  
Cu Alloy ◽  
Pure Cu

Highly-aligned flake graphite (FG) reinforced Cu matrix composites with high thermal conductivity and adaptive coefficient of thermal expansion were successfully prepared via the collaborative process of tape-casting and hot-pressing sintering. To overcome the problem of fragile interface, Zr-Cu alloy powder was introduced instead of pure Zr powder to enhance the interfacial strength, ascribed to the physical-chemical bonding at the Cu-FG interface. The results indicate that the synthetic ZrC as interfacial phase affects the properties of FG/Cu composites. The thermal conductivity reaches the maximum value of 608.7 W/m∙K (52% higher than pure Cu) with 0.5 wt % Zr. Surprisingly, the negative coefficient of thermal expansion (CTE) in the Z direction is acquired from −7.61 × 10−6 to −1.1 × 10−6/K with 0 to 2 wt % Zr due to the physical mechanism of strain-engineering of the thermal expansion. Moreover, the CTE in X-Y plane with Zr addition is 8~10 × 10−6/K, meeting the requirements of semiconductor materials. Furthermore, the bending strength of the FG/Cu-2 wt % Zr composite is 42% higher than the FG/Cu composite. Combining excellent thermal conductivity with ultralow thermal expansion make the FG/Cu-Zr composites be a highly promising candidate in the electronic packaging field.

scholarly journals Effects of polymorphic form and particle size of SiO2 fillers on the properties of SiO2–PEEK composites

2021 ◽  
Vol 11 (04) ◽  
pp. 2150021
Author(s):  
Peng Jie Xue ◽  
Shi Lin Liu ◽  
Jian Jiang Bian
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Thermal Expansion ◽  
Dielectric Loss ◽  
Mechanical Strength ◽  
Polymorphic Form ◽  
Fused Silica ◽  
High Frequencies ◽  
Silica Fillers ◽  
Filled Composite

The effects of polymorphic form and particle size of SiO2 fillers on the dielectric, mechanical and thermal properties of SiO2–Polyetheretherketone (SiO2–PEEK) composites were investigated in this paper. Strong low frequency (<10Hz) Debye-like dielectric dispersions could be observed for all samples. The dielectric permittivity at high frequencies of the composite exhibits little morphology or particle size-sensitive characteristics of the SiO2 fillers. All the composites obtained in this case demonstrate the dielectric permittivities of [Formula: see text] at high frequencies. The crystalline [Formula: see text]-cristobalite filled composite exhibits lower dielectric loss and mechanical strength, but larger thermal expansion coefficient and thermal conductivity, compared with the similar particle sized amorphous SiO2 filled one. The crystalline [Formula: see text]-quartz filled composite demonstrates the lowest mechanical strength and highest dielectric loss. An increase in particle size of the spherical fused silica fillers decreases the dielectric loss, while increases the thermal conductivity of the composite. The flexural strength of the composite reaches the maximum value of 113 MPa when the particle size of spherical SiO2 filler is [Formula: see text]m. Particle packing by combining optimal amounts of differently sized spherical fused silica fillers leads to a substantial improvement of mechanical strength (153MPa) coupled with reasonable dielectric and thermal properties due to the synergic effect (dielectric permittivity ([Formula: see text] = 3.35, dielectric loss (tan[Formula: see text] @10 GHz, thermal conductivity ([Formula: see text] = 0.74 W/m*k ([Formula: see text]C), coefficient of thermal expansion ([Formula: see text]C and relative density ([Formula: see text]) = 99.72%).

Flexible Ceramic-Polymer Composite Substrates with Spatially Variable Dielectrics for Miniaturized RF Applications

2009 ◽  
Vol 1161 ◽  
Author(s):  
Zuhal Tasdemir ◽  
Gullu Kiziltas
Keyword(s):  
Dielectric Constant ◽  
Tape Casting ◽  
Composite Films ◽  
Spatial Arrangement ◽  
Ceramic Composites ◽  
Dielectric Constants ◽  
Novel Material ◽  
The Difference ◽  
High Dielectric ◽  
Tape Cast

AbstractThe goal of this research is to develop a process suitable for producing monolithic conformal substrates with a spatial arrangement of material cells according to a particular design creating novel material systems, useful for many multi- functional electronic and Radio Frequency devices. In this study, MCT ceramics (Mg-Ca-Ti-O systems) and organic binders (polymer solution) are mixed and fabricated as films through a process called tape casting to compromise between high dielectric constant and flexibility. Prior to optimizing the process, several characterization studies are carried out: Commercial spray dried MCT powders (Transtech Inc.) with dielectric constant k=70 and k=20 were analyzed as pressed and produced into tape cast films. Dielectric properties are then measured by an Agilent 16451B material analysis kit and their microscopic behavior is examined by scanning electron microscopy. Results show that flexible composite films show a maximum dielectric constant of ε∼22 unlike their powder pressed form with ε ∼16 but their loss behavior deteriorates when compared with their sintered form and a loss tangent factor of 0.001. The difference is attributed to the air content vs. polymer presence of the material in powder pressed form. Also, these substrates naturally are no longer flexible; hence studies are focused on their tape cast form. The potential of these dielectric shades to serve as candidate constituents for producing monolithic textured polymer-ceramic-composites with controllable loss is studied further. Four properties are of prime importance: tunability of dielectric constants to achieve miniaturization, flexibility via low temperature processing of polymers and loss controllability.

Composites for Electronic Substrate Applications

1987 ◽  
Vol 108 ◽  
Author(s):  
R. Gerhardt
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Thermal Expansion ◽  
Experimental Evidence ◽  
Single Phase ◽  
High Thermal Conductivity ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
Composite Approach ◽  
Electronic Substrates

ABSTRACTThe need for low dielectric constant, high thermal conductivity, matched thermal expansion and co-processability in electronic substrates is reviewed. Since no single phase material is able to satisfy all the requirements, a microscopic composite approach is proposed. Recent experimental evidence supporting the concept is also presented.

Mullite Ceramics for the Application to Advanced Packaging Technology

1989 ◽  
Vol 154 ◽  
Author(s):  
Jun Tanaka ◽  
Satoshi Kajita ◽  
Masami Terasawa
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Thermal Expansion ◽  
Aluminum Nitride ◽  
Heat Sink ◽  
High Thermal Conductivity ◽  
System A ◽  
Lower Dielectric Constant ◽  
Advanced Packaging ◽  
Mullite Ceramics

AbstractMullite ceramics were developed for multilayered packages, which have a lower dielectric constant and a nearer thermal expansion to that of silicon than those of alumina. The multilayered mullite packages are manufactured by using a similar cofired technology with tungsten or molybdenum to the conventionally used alumina system. A new brazing material and a new lead material were developed to be combined with the mullite ceramics Multilayered mullite packages with a brazed aluminum nitride heat sink, which has a high thermal conductivity, were developed to compensate a low thermal conductivity of the mullite itself. The packages are one of the highest performance packages.

Plasma Enhanced Chemical Vapor Deposition of Porous Organosilicate Glass ILD Films With k ≤ 2.4.

2003 ◽  
Vol 766 ◽  
Author(s):  
Raymond N. Vrtis ◽  
Mark L. O'Neill ◽  
Jean L. Vincent ◽  
Aaron S. Lukas ◽  
Brian K. Peterson ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Chemical Vapor Deposition ◽  
Mechanical Strength ◽  
Thermal Annealing ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Organosilicate Glass

AbstractWe report on our work to develop a process for depositing nanoporous organosilicate (OSG) films via plasma enhanced chemical vapor deposition (PECVD). This approach entails codepositing an OSG material with a plasma polymerizable hydrocarbon, followed by thermal annealing of the material to remove the porogen, leaving an OSG matrix with nano-sized voids. The dielectric constant of the final film is controlled by varying the ratio of porogen precursor to OSG precursor in the delivery gas. Because of the need to maintain the mechanical strength of the final material, diethoxymethylsilane (DEMS) is utilized as the OSG precursor. Utilizing this route we are able to deposit films with a dielectric constant of 2.55 to 2.20 and hardness of 0.7 to 0.3 GPa, respectively.

A Study of Some Mechanical and Physical Properties for Palm Fiber/Polyester Composite

2020 ◽  
Vol 38 (3B) ◽  
pp. 104-114
Author(s):  
Samah M. Hussein
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Date Palm ◽  
Volume Fraction ◽  
Unsaturated Polyester ◽  
Dielectric Strength ◽  
Palm Fiber ◽  
Mechanical And Physical Properties ◽  
Polyester Composite

This research has been done by reinforcing the matrix (unsaturated polyester) resin with natural material (date palm fiber (DPF)). The fibers were exposure to alkali treatment before reinforcement. The samples have been prepared by using hand lay-up technique with fiber volume fraction of (10%, 20% and 30%). After preparation of the mechanical and physical properties have been studied such as, compression, flexural, impact strength, thermal conductivity, Dielectric constant and dielectric strength. The polyester composite reinforced with date palm fiber at volume fraction (10% and 20%) has good mechanical properties rather than pure unsaturated polyester material, while the composite reinforced with 30% Vf present poor mechanical properties. Thermal conductivity results indicated insulator composite behavior. The effect of present fiber polar group induces of decreasing in dielectric strength, and increasing dielectric constant. The reinforcement composite 20% Vf showed the best results in mechanical, thermal and electrical properties.

Characterization of Interconnect Defects Using Scanning Thermal Conductivity Microscopy

2004 ◽  
Author(s):  
H.W. Ho ◽  
J.C.H. Phang ◽  
A. Altes ◽  
L.J. Balk
Keyword(s):  
Thermal Conductivity ◽  
Integrated Circuits ◽  
Large Scale

Abstract In this paper, scanning thermal conductivity microscopy is used to characterize interconnect defects due to electromigration. Similar features are observed both in the temperature and thermal conductivity micrographs. The key advantage of the thermal conductivity mode is that specimen bias is not required. This is an important advantage for the characterization of defects in large scale integrated circuits. The thermal conductivity micrographs of extrusion, exposed and subsurface voids are presented and compared with the corresponding topography and temperature micrographs.

scholarly journals Fabrication and Characterization of the Modified EV31-Based Metal Matrix Nanocomposites

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 125
Author(s):  
Seyed Kiomars Moheimani ◽  
Mehran Dadkhah ◽  
Mohammad Hossein Mosallanejad ◽  
Abdollah Saboori
Keyword(s):  
Thermal Expansion ◽  
Mechanical Strength ◽  
Metal Matrix ◽  
Coefficient Of Thermal Expansion ◽  
Structural Effect ◽  
Metal Matrix Nanocomposites ◽  
Mechanical Stirring ◽  
Specific Strength ◽  
The Matrix ◽  
Matrix Nanocomposites

Metal matrix nanocomposites (MMNCs) with high specific strength have been of interest for numerous researchers. In the current study, Mg matrix nanocomposites reinforced with AlN nanoparticles were produced using the mechanical stirring-assisted casting method. Microstructure, hardness, physical, thermal and electrical properties of the produced composites were characterized in this work. According to the microstructural evaluations, the ceramic nanoparticles were uniformly dispersed within the matrix by applying a mechanical stirring. At higher AlN contents, however, some agglomerates were observed as a consequence of a particle-pushing mechanism during the solidification. Microhardness results showed a slight improvement in the mechanical strength of the nanocomposites following the addition of AlN nanoparticles. Interestingly, nanocomposite samples were featured with higher electrical and thermal conductivities, which can be attributed to the structural effect of nanoparticles within the matrix. Moreover, thermal expansion analysis of the nanocomposites indicated that the presence of nanoparticles lowered the Coefficient of Thermal Expansion (CTE) in the case of nanocomposites. All in all, this combination of properties, including high mechanical strength, thermal and electrical conductivity, together with low CTE, make these new nanocomposites very promising materials for electro packaging applications.

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