Influence of Moisture-Uptake on Mechanical Properties of Polymers Used in Microelectronics

1998 ◽  
Vol 511 ◽  
Author(s):  
R. Buchhold ◽  
A. Nakladal ◽  
G. Gerlach ◽  
K. Sahre ◽  
K.-J. Eichhorn ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymer Films ◽  
Semiconductor Device ◽  
Mechanical Stability ◽  
Climatic Conditions ◽  
Device Fabrication ◽  
Film Stress ◽  
Moisture Uptake ◽  
Out Of Plane ◽  
The Impact

ABSTRACTPolymers are currently considered as a possible alternative to silicon dioxide in the fabrication of interlevel dielectrics. To penetrate mainstream semiconductor device fabrication polymers have to meet a number of requirements regarding their long-term stability. One aspect is the mechanical stability of integrated polymer films under changing climatic conditions. In the present work, the impact of ambient moisture on the mechanical properties of thin polymer films (PI, BCB, and PFCB) was investigated. The sorption of water molecules in these materials typically causes an anisotropic volume expansion, resulting in increased mechanical film stress if the film is physically constrained by adjacent inorganic structures. Especially polyimides show both considerable moisture uptake and large changes in the mechanical film stress, while BCB and PFCB are virtually insensitive to ambient moisture. In the paper, experimental data (water uptake, in-plane swelling, out-of-plane swelling) are presented and discussed in detail.

Effect of CNT Grafting on Carbon Fibers on Impact Properties of CFRTP Laminate

2018 ◽  
Vol 774 ◽  
pp. 410-415 ◽  
Author(s):  
Kazuto Tanaka ◽  
Ken Uzumasa ◽  
Tsutao Katayama
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Interfacial Strength ◽  
Fiber Surface ◽  
Impact Properties ◽  
Specific Strength ◽  
Out Of Plane ◽  
Reinforced Thermoplastics ◽  
The Impact

Carbon fiber reinforced thermoplastics (CFRTP) are expected to be used as a structural material for aircraft and automobiles not only for their mechanical properties such as high specific strength and high specific rigidity but also for their high recyclability and short molding time. Generally, in a composite material having a laminated structure, interlaminar delamination is often caused by an out-of-plane impact, so the interlayer property plays an important role in the mechanical properties. It has been reported that the fiber/matrix interfacial strength increases by grafting carbon nanotubes (CNT) on the carbon fiber surface. In this study, CNT grafted carbon fibers were used for reinforcement of CFRTP laminate for the improvement of impact properties of CFRTP laminates. The impact absorbed energy of the CFRTP laminate using CNT grafted carbon fibers as reinforcing fiber was higher than that using untreated CF.

The Interplay of Thermo-Mechanical Properties in the Growth and Processing of III-V Materials

1991 ◽  
Vol 226 ◽  
Author(s):  
A. S. Jordan ◽  
V. Swaminathan
Keyword(s):  
Mechanical Properties ◽  
Shear Stress ◽  
Dislocation Density ◽  
Semiconductor Device ◽  
Electronic Devices ◽  
Device Fabrication ◽  
Device Performance ◽  
Bulk Crystals ◽  
Dislocation Generation ◽  
Critical Resolved Shear Stress

AbstractThe thermo-mechanical properties of III-V semiconductors, in general, and of GaAs and InP in particular, are reviewed. They play an important role in many aspects of semiconductor device fabrication starting from the growth of bulk crystals. Dislocation generation in GaAs and InP are discussed with the emphasis on the theoretical and experimental aspects of reducing the dislocation density in these materials. Such mechanical properties as glide systems, critical resolved shear stress and impurity hardening are covered. The effects of dislocations on device performance are illustrated with examples from photonic and electronic devices. Finally, the effect of thermomechanical stresses in the degradation and reliability of GaAs/AlGaAs and InP/InGaAsP based opto-electronic devices is considered.

scholarly journals Mechanical Characterization of Rose Bengal and Green Light Crosslinked Collagen Scaffolds for Regenerative Medicine

2021 ◽  
Author(s):  
Joy Braun ◽  
Stefanie Eckes ◽  
Michelle Fiona Kilb ◽  
Dirk Fischer ◽  
Claudia Eßbach ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Rose Bengal ◽  
Mechanical Stability ◽  
Green Light ◽  
Tensile Tests ◽  
Linear Increase ◽  
Cell Contact ◽  
Collagen Scaffolds ◽  
Photochemical Crosslinking ◽  
The Impact

Abstract Collagen is one of the most important biomaterials for tissue engineering approaches. Despite its excellent biocompatibility, it shows the non-negligible disadvantage of poor mechanical stability. Photochemical crosslinking with rose bengal and green light (RGX) is an appropriate method to improve this property. The development of collagen laminates is helpful for further adjustment of the mechanical properties as well as the controlled release of incorporated substances. In this study, we investigate the impact of crosslinking and layering of two different collagen scaffolds on the swelling behavior and mechanical behavior in micro tensile tests to obtain information on its wearing comfort (stiffness, strength and ductility). The mechanical stability of the collagen material after degradation due to cell contact is examined using thickness measurements. There is no linear increase or decrease due to layering homologous laminates. Unexpectedly, a decrease in elongation at break, Younǵs modulus and ultimate tensile strength is measured when the untreated monolayer is compared to the crosslinked one. Furthermore we can detect a connection between stability and cell proliferation. The results show that with variation in number and type of layers, collagen scaffolds with tailored mechanical properties can be produced. Such a multi-layered structure enables the release of biomolecules into inner or outer layers for biomedical applications.

Analysis of the Mechanical Properties of Pristine and Thermally Aged PC/PMMA Micro and Nanolayered Films

2010 ◽  
Author(s):  
Hui Shen ◽  
N. D. Gannon
Keyword(s):  
Mechanical Properties ◽  
Film Thickness ◽  
Polymer Films ◽  
Thermal Aging ◽  
Layered Structures ◽  
Mechanical Tests ◽  
Hierarchical Systems ◽  
Process Technology ◽  
Barrier Materials ◽  
The Impact

Microlayered polymer films are synthetic polymers with biomimicking layered structures which have been successfully commercialized. Nanolayered polymer films have been developed in recent years using advanced process technology. The innovative nanolayered polymer films have more complex hierarchical systems with truly biomimic nature. There are many potential applications for the nanolayered films such as gas barrier materials and spherical gradient refractive index lens. However, as polymers possess many properties that are different from metals and other traditional materials, the mechanical properties of the polymer films can vary widely depending on the material formulation, environmental temperature, and time. In this work, standard mechanical tests have been conducted to study the relationship between the mechanical properties and the layered structures. The impact of thermal aging on the mechanical behavior of the micro and nanolayered polymer films has also been investigated experimentally. The composition of the polymer films under study are 50vol% polycarbonate (PC) and 50vol% poly(methyl methacrylate) (PMMA). The layer thickness ranges from 31 nm to 32 μm and the film thickness 50.8 μm to 254 μm. These films were thermally aged at 115°C and 125°C in a constant temperature oven for up to four weeks. The mechanical properties, including the modulus of elasticity, tensile strength and ductility, have been tested on the pristine and thermally aged films. It has been observed that the mechanical properties of the films vary with the layered structure and film thickness. The thermal aging temperature and aging time have significant effects on the overall character of the stress-strain responses. Films with different thicknesses and layer formations respond to the thermal conditions differently.

The Low-Nickel Cryogenic Steel Alloyed by Nitrogen

2016 ◽  
Vol 879 ◽  
pp. 1899-1904 ◽  
Author(s):  
Anatoly G. Svyazhin ◽  
Ludmila M. Kaputkina ◽  
Inga V. Smarygina
Keyword(s):  
Mechanical Properties ◽  
Mechanical Stability ◽  
Climatic Conditions ◽  
Solid Solution Hardening ◽  
The Arctic ◽  
Solution Hardening ◽  
Service Conditions ◽  
High Level ◽  
Hot Rolled ◽  
Cryogenic Steel

New low-nickel Cr18Ni5Mn9Mo2N and Cr19Ni6Mn10Mo2N steels can be used up to-170 °C and differs in the highest level of durabilities in the hot-rolled and tempered from austenitic area state that provides its effective application in climatic conditions of the Arctic and Antarctic. Excess of durability over level, characteristic for traditional stainless steel of the Cr18Ni9 type, is provided due to additional solid solution hardening. Alloying with nitrogen to 0,18÷0,22% usual Cr18Ni9 steel has the smaller, but also high level of mechanical properties, differs in smaller thermal and mechanical stability of austenite and can be applied in less rigid on temperature and loadings service conditions. Corrosion resistance of austenitic stable steels free from contaminations is also higher compared to steel with regular cleanliness.

scholarly journals Review of Through-the-Thickness Reinforced z-Pinned Composites

2020 ◽  
Vol 4 (1) ◽  
pp. 31 ◽  
Author(s):  
Vassilis Kostopoulos ◽  
Nikolaos Sarantinos ◽  
Stavros Tsantzalis
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Fatigue Loading ◽  
Mode I ◽  
Mode Ii ◽  
Impact Properties ◽  
Compression After Impact ◽  
Out Of Plane ◽  
Plane Direction ◽  
The Impact

This work reviews the effects of z-Pins used in composite laminates as through-the-thickness reinforcement to increase the composite’s properties in the out-of-plane direction. The paper presents the manufacture and microstructure of this reinforcement type while also incorporating the impact of z-Pins on the mechanical properties of the composite. Mechanical properties include tensile, compression, flexure properties in static, dynamic and fatigue loads. Additionally, mode I and mode II properties in both static and fatigue loading are presented, as well as hygrothermal, impact and compression after impact properties.

scholarly journals Comparative Effect of Self- or Dual-Curing on Polymerization Kinetics and Mechanical Properties in a Novel, Dental-Resin-Based Composite with Alkaline Filler

Materials ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 108 ◽  
Author(s):  
Nicoleta Ilie
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Mechanical Stability ◽  
Polymerization Kinetics ◽  
Dental Resin ◽  
Polymerization Kinetic ◽  
Double Bond Conversion ◽  
Light Curing ◽  
Dual Curing ◽  
The Impact

Dental bulk-fill restorations with resin-composites (RBC) are increasing in popularity, but doubts concerning insufficient curing in depth still disconcert clinicians. An alternative might be offered by modern dual-cured RBCs, which additionally provide bioactive properties. This study assessed the impact of additional light-curing on polymerization kinetics, the degree of conversion (DC) and mechanical properties of a novel, dual-cured RBC with alkaline fillers. Since the bioactivity of a material often implies a release of compounds, the mechanical stability in simulated clinical environments was also evaluated. Polymerization kinetics and DC were assessed at 2- and 4-mm specimen depths in real-time up to one hour (n = 6). Incident and transmitted irradiance and radiant exposure were recorded at 2- and 4-mm depths. Micro-mechanical profiles (n = 6) were assessed in 100-µm steps along 6-mm deep specimens at 24 h post-polymerization. Flexural strength and modulus (n = 10) were determined up to three months of immersion in neutral (6.8) and acidic (4) pH conditions. DC variation in time was best described by a sigmoidal function (R2 > 0.98), revealing a retarded (3.4 ± 0.4 min) initiation in C=C double bond conversion in self-cured versus dual-cured specimens. The setting reaction kinetic was identical at 2- and 4-mm depths for the self-cure mode. For the dual-cure mode, polymerization initiated at 2-mm depth instantly with light-irradiation, while being retarded (0.8 min) at 4-mm depth. The material behaves similarly, irrespective of curing mode or depth, later than 11 min after mixing. Flexural strength and modulus was comparable to regular RBCs and maintained up to three months in both neutral and acidic conditions. Additional light-curing initially accelerates the polymerization kinetic and might help shorten the restauration procedure by hardening the material on demand, however with no effect on the final properties.

scholarly journals The influence of artificial aging on recyclability and mechanical stability of pharmaceutical packaging

2020 ◽  
Author(s):  
Marina Vukoje ◽  
◽  
Ivana Bolanča Mirković ◽  
Martina Bešlić ◽  
Gorana Petković ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Image Analysis ◽  
Optical Properties ◽  
Mechanical Stability ◽  
Accelerated Aging ◽  
Weather Conditions ◽  
Recycled Fibres ◽  
Printing Ink ◽  
The Impact

Recycling of wastepaper and packaging is one of the most desirable options for the purpose of preservation the environment and increasing the sustainability of production. Changes in customer behaviour have increased a demand for packaging materials, such as the growth of online shopping and/or demand for optimal sized packaging foods and medicines. During storage and transport, products can be exposed to different weather conditions, which ultimately affects their quality and disposal. Therefore, in this paper, the influence of moisture and temperature on the mechanical properties of pharmaceutical packaging as well as on the possibility of their recycling was investigated. The printed and formed pharmaceutical packaging was subjected to a process of accelerated aging in a chamber under the action of temperature and humidity, according to standard methods and defined conditions. Thereafter, the samples were subjected to mechanical testing to determine the effect of moisture on the mechanical properties. In addition, the impact of moisture on pharmaceutical packaging recycling performance was examined. Recycling was carried out in laboratory conditions by chemical deinking flotation according to the INGEDE 11 method, while the obtained recycled laboratory sheets were characterized by the determination of optical properties and the image analysis. It was found that the mechanical properties of the tested pharmaceutical packaging were deteriorated. From the results obtained by determination of the optical properties, in recycled samples the brightness decreases with aging. As the sample ages, the printing ink binds to the recycled fibres, so the ERIC is lower in recycled fibres obtained from non-aged samples compared to the old ones. The CIE coefficient b* is higher for samples obtained from recycling of aged pharmaceutical packaging than for samples obtained from recycling of non-aged samples, and aged recycled samples will be yellower than non-aged ones. Therefore, the whiteness is lower in recycled fibres obtained from aged samples. When measuring the image analysis, the obtained results show that the number of ink particles and their surface area are significantly reduced with the duration of aging time.

Behavior of contact-silicided TFSOI gate structures

1994 ◽  
Vol 52 ◽  
pp. 860-861
Author(s):  
N. David Theodore ◽  
Juergen Foerstner ◽  
Peter Fejes
Keyword(s):  
Semiconductor Device ◽  
Series Resistance ◽  
Field Effect Transistors ◽  
Silicon Layer ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
Continuous Layer ◽  
Buried Oxide ◽  
Device Structures ◽  
Thin Silicon

As semiconductor device dimensions shrink and packing-densities rise, issues of parasitic capacitance and circuit speed become increasingly important. The use of thin-film silicon-on-insulator (TFSOI) substrates for device fabrication is being explored in order to increase switching speeds. One version of TFSOI being explored for device fabrication is SIMOX (Silicon-separation by Implanted OXygen).A buried oxide layer is created by highdose oxygen implantation into silicon wafers followed by annealing to cause coalescence of oxide regions into a continuous layer. A thin silicon layer remains above the buried oxide (~220 nm Si after additional thinning). Device structures can now be fabricated upon this thin silicon layer.Current fabrication of metal-oxidesemiconductor field-effect transistors (MOSFETs) requires formation of a polysilicon/oxide gate between source and drain regions. Contact to the source/drain and gate regions is typically made by use of TiSi2 layers followedby Al(Cu) metal lines. TiSi2 has a relatively low contact resistance and reduces the series resistance of both source/drain as well as gate regions

Impact of roof shading on building energy performance in warm & humid climatic places of India

2020 ◽  
pp. 50-64
Author(s):  
Kuladeep Kumar Sadevi ◽  
Avlokita Agrawal
Keyword(s):  
Energy Consumption ◽  
Energy Conservation ◽  
Energy Performance ◽  
General Assumption ◽  
Climatic Conditions ◽  
Building Envelope ◽  
Passive Cooling ◽  
Base Case ◽  
U Value ◽  
The Impact

With the rise in awareness of energy efficient buildings and adoption of mandatory energy conservation codes across the globe, significant change is being observed in the way the buildings are designed. With the launch of Energy Conservation Building Code (ECBC) in India, climate responsive designs and passive cooling techniques are being explored increasingly in building designs. Of all the building envelope components, roof surface has been identified as the most significant with respect to the heat gain due to the incident solar radiation on buildings, especially in tropical climatic conditions. Since ECBC specifies stringent U-Values for roof assembly, use of insulating materials is becoming popular. Along with insulation, the shading of the roof is also observed to be an important strategy for improving thermal performance of the building, especially in Warm and humid climatic conditions. This study intends to assess the impact of roof shading on building’s energy performance in comparison to that of exposed roof with insulation. A typical office building with specific geometry and schedules has been identified as base case model for this study. This building is simulated using energy modelling software ‘Design Builder’ with base case parameters as prescribed in ECBC. Further, the same building has been simulated parametrically adjusting the amount of roof insulation and roof shading simultaneously. The overall energy consumption and the envelope performance of the top floor are extracted for analysis. The results indicate that the roof shading is an effective passive cooling strategy for both naturally ventilated and air conditioned buildings in Warm and humid climates of India. It is also observed that a fully shaded roof outperforms the insulated roof as per ECBC prescription. Provision of shading over roof reduces the annual energy consumption of building in case of both insulated and uninsulated roofs. However, the impact is higher for uninsulated roofs (U-Value of 3.933 W/m2K), being 4.18% as compared to 0.59% for insulated roofs (U-Value of 0.33 W/m2K).While the general assumption is that roof insulation helps in reducing the energy consumption in tropical buildings, it is observed to be the other way when insulation is provided with roof shading. It is due to restricted heat loss during night.

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