Advanced Adhesion Strength Testing Methods of Thin Film Multilayers in Electronic Packaging Systems

With the continued miniaturization and increasing performance of electronic devices, new technical challenges have arisen. One such issue is delamination occurring at critical interfaces inside the device. This major reliability issue can occur during the manufacturing process or during normal use of the device. Proper evaluation of the adhesion strength of critical interfaces early in the product development cycle can help reduce reliability issues and time-to-market of the product. However, conventional adhesion strength testing is inherently limited in the face of package miniaturization, which brings about further technical challenges to quantify design integrity and reliability. Although there are many different interfaces in today's advanced electronic packages, they can be generalized into two main categories: 1) rigid to rigid connections with a thin flexible polymeric layer in between, or 2) a thin film membrane on a rigid structure. Knowing that every technique has its own advantages and disadvantages, multiple testing methods must be enhanced and developed to be able to accommodate all the interfaces encountered for emerging electronic packaging technologies. For evaluating the adhesion strength of high adhesion strength interfaces in thin multilayer structures a novel adhesion test configuration called “single cantilever adhesion test (SCAT)” is proposed and implemented for an epoxy molding compound (EMC) and photo solder resist (PSR) interface. The test method is then shown to be capable of comparing and selecting the stronger of two potential EMC/PSR material sets. Additionally, a theoretical approach for establishing the applicable testing domain for a four-point bending test method was presented. For evaluating polymeric films on rigid substrates, major testing challenges are encountered for reducing testing scatter and for factoring in the potentially degrading effect of environmental conditioning on the material properties of the film. An advanced blister test with predefined area test method was developed that considers an elasto-plastic analytical solution and implemented for a conformal coating used to prevent tin whisker growth. The advanced blister testing with predefined area test method was then extended by employing a numerical method for evaluating the adhesion strength when the polymer’s film properties are unknown.

Modified atmosphere packaging effects on the postharvest quality of papaya fruit

Export of Fijian papaya (Carica papaya) fruit to destinations such as New Zealand has increased significantly over the last several years. Shipment by sea rather than air is the preferred method, given the capacity for larger volumes and reductions in cost. Long shipping times, however, can compromise fruit quality, although the use of modified atmosphere packaging (MAP) may provide a viable solution for extending fruit storage life. In a collaborative ACIAR project, Australian and Fijian researchers investigated the potential of using MAP to extend storage life of a Fijian papaya ('Fiji Red') fruit based on simulated sea transport conditions. Fruit were packed in one of three MAP environments within cartons, consisting of either a (1) Low Density Polyethylene (LDPE) bag with 10 g of KMnO4, (2) Polyamide Film (PF) bag with macro-perforations or (3) without a bag (control fruit). Fruit were held for 1, 2 or 3 weeks at 10°C before being unpacked, ripened and assessed for quality. On day 6 after outturn, fruit with the highest overall quality were those held in LDPE bags. LDPE fruit generally coloured up faster at outturn than PF or control fruit, had less overall moisture loss and scored high in flavour. Headspace carbon dioxide and oxygen concentrations within the LDPE bags were also near recommended levels for maintaining optimum storage-life quality. The LDPE bag provided the most suitable conditions for long term storage of fresh papaya fruit and is therefore the recommended MAP type for use with sea freight export out of Fiji.

Electronic Packaging of Paper-Based Anisotropic Magnetoresistive Sensors

This report investigates adaptations of electronic packaging methods used to create stacks of these sensors. Four methods were developed and tested to determine the best option in terms of mechanical stability and electrical conductivity of the system. For the first method, a stack is created by way of through paper vias (TPVs), a hole that is cut in the pads of the sensors and then filled with electrically conductive adhesive through the openings on the two sensors to be joined. The second method is called mechanical caulking and connects sensors through pads which have been lined with copper tape backed with conductive adhesive. The connection is created with a small copper rivet which is flattened in place by compressive force. The third method is the stitching method which is inspired by sewing of fabric. A pattern of thin copper wire is stitched on the pad of a sensor that is lined with copper tape backed with conductive adhesive. The wire is then stitched through a second sensor that is treated similarly with copper tape and the stack receives the same pattern through the two layers as was applied to the first sensor alone. The final method is the collapsed daisy chain which is the linear connection of sensors to their neighboring sensors via copper tape backed with conductive adhesive. The row of sensors is then collapsed in an alternating orientation into a single stack.

Use of inert gas-enriched atmospheres and post-packaging irradiation in shelf-life extension of watercress

Watercress (Nasturtium officinale R. Br.) is a semi-aquatic plant of the Brassicaceae family highly appreciated in the Mediterranean cuisine. It features sharp, peppery and slightly tangy taste and contains health-promoting phytochemicals. Its consumption as a fresh-cut product has increased in recent years, as well as the global market of minimally processed vegetables. This demand is driven by the growing interest in the role of food in promoting the human health and wellbeing and to meet consumer needs for fresh-like and more convenient foods. Due to the reduced shelf-life of this plant, the suitability of inert gas-enriched atmospheres and ionizing irradiation for preserving visual, nutritional and functional quality attributes during cold storage was studied. Watercress samples were gathered in the Northeast region of Portugal, rinsed in tap water and a portion was immediately analyzed (non-stored control). The remaining fresh material was packaged in polyethylene bags under N2- and Ar-enriched atmospheres, conventional atmosphere (air) and vacuum (no atmosphere). Samples under conventional atmosphere were irradiated at 1, 2 and 5 kGy of gamma-rays (predicted doses) in a 60Co experimental chamber. A non-irradiated control followed all the experiment. Then, all packaged samples were stored at 4 ºC for 7 days. The studied quality parameters included the colour that was measured with a Konica Minolta colorimeter, and total soluble solids and pH determined in squeezed juice. The proximate composition (moisture, proteins, fat, ash, carbohydrates and energy) was evaluated using the AOA C procedures. Organic acids, free sugars, fatty acids and tocopherols were analyzed by chromatographic techniques. Samples were also evaluated for its DPPH• scavenging activity, reducing power, and lipid peroxidation inhibition capacity trough the inhibition of the β-carotene bleaching and thiobarbituric acid reactive substances (TBAR S) formation. Differences among treatments were analyzed using the one-way analysis of variance (ANO VA) and a linear discriminant analysis (LDA ) was used to evaluate the effects on the overall postharvest quality. After evaluating the effect on the individual quality parameters, the LDA revealed that the Ar-enriched atmosphere and the irradiation at 2 kGy were suitable processing choices for preserving the integrity of the non-stored control samples during cold storage. Thus, these non-thermal treatments were highlighted for shelf-life extension of fresh-cut watercress.

Advanced parametrical modelling of 24 GHz radar sensor IC packaging components

This paper deals with the development of an advanced parametrical modelling concept for packaging components of a 24 GHz radar sensor IC used in automotive driver assistance systems. For fast and efficient design of packages for system-in-package modules (SiP), a simplified model for the description of parasitic electromagnetic effects within the package is desirable, as 3-D field computation becomes inefficient due to the high density of conductive elements of the various signal paths in the package. By using lumped element models for the characterization of the conductive components, a fast indication of the design's signal-quality can be gained, but so far does not offer enough flexibility to cover the whole range of geometric arrangements of signal paths in a contemporary package. This work pursues to meet the challenge of developing a flexible and fast package modelling concept by defining parametric lumped-element models for all basic signal path components, e.g. bond wires, vias, strip lines, bumps and balls. © Author(s) 2011. CC Attribution 3.0 License.

Postharvest quality changes in fresh-cut watercress stored under conventional and inert gas-enriched modified atmosphere packaging

The effect of modified atmosphere packaging (MAP) on the postharvest quality of fresh-cut watercress (Nasturtium officinale R. Br.) stored at 4 ºC for 7 d was studied. A portion of watercress was immediately analyzed (non-stored control) and the remaining fresh material was stored packaged under atmospheres enriched with N2, Ar, air, or vacuum. The analyzed parameters included colour, total soluble solids, pH, macronutrients, the individual profiles of sugars, organic acids, tocopherols and fatty acids, and total phenolics and flavonoids. Furthermore, four in vitro assays were performed to evaluate the antioxidant activity. After assessing the effect on individual quality parameters, it was possible to conclude that air was the less efficient atmosphere in preserving quality attributes of the non-stored control samples during cold storage. In turn, Ar-enriched MAP was the most suitable choice to preserve the overall postharvest quality. The present study also highlighted the nutritional and antioxidant properties of watercress, as well as the interest of its inclusion in human diets.

Evaluation of the Genotoxicity of Chitosan Nanoparticles for Use in Food Packaging Films

The use of nanoparticles in food packaging has been proposed on the basis that it could improve protection of foods by, for example, reducing permeation of gases, minimizing odor loss, and increasing mechanical strength and thermal stability. Consequently, the impacts of such nanoparticles on organisms and on the environment need to be investigated to ensure their safe use. In an earlier study, Moura and others (2008a) described the effect of addition of chitosan (CS) and poly(methacrylic acid) (PMAA) nanoparticles on the mechanical properties, water vapor, and oxygen permeability of hydroxypropyl methylcellulose films used in food packaging. Here, the genotoxicity of different polymeric CS/PMAA nanoparticles (size 60, 82, and 111 nm) was evaluated at different concentration levels, using the Allium cepa chromosome damage test as well as cytogenetic tests employing human lymphocyte cultures. Test substrates were exposed to solutions containing nanoparticles at polymer mass concentrations of 1.8, 18, and 180 mg/L. Results showed no evidence of DNA damage caused by the nanoparticles (no significant numerical or structural changes were observed), however the 82 and 111 nm nanoparticles reduced mitotic index values at the highest concentration tested (180 mg/L), indicating that the nanoparticles were toxic to the cells used at this concentration. In the case of the 60 nm CS/PMAA nanoparticles, no significant changes in the mitotic index were observed at the concentration levels tested, indicating that these particles were not toxic. The techniques used show promising potential for application in tests of nanoparticle safety envisaging the future use of these materials in food packaging.

Packaging as a vehicle of nutritional information for children: Enhancing children’s perceptions of healthy food

Field lab in marketing: Children consumer behaviour

Packaging and Deployment of Large Planar Spacecraft Structures

This thesis presents a set of novel methods to biaxially package planar structures by folding and wrapping. The structure is divided into strips connected by folds that can slip during wrapping to accommodate material thickness. These packaging schemes are highly efficient, with theoretical packaging efficiencies approaching 100%. Packaging tests on meter-scale physical models have demonstrated packaging efficiencies of up to 83%. These methods avoid permanent deformation of the structure, allowing an initially flat structure to be deployed to a flat state.

Also presented are structural architectures and deployment schemes that are compatible with these packaging methods. These structural architectures use either in-plane pretension -- suitable for membrane structures -- or out-of-plane bending stiffness to resist loading. Physical models are constructed to realize these structural architectures. The deployment of these types of structures is shown to be controllable and repeatable by conducting experiments on lab-scale models.

These packaging methods, structural architectures, and deployment schemes are applicable to a variety of spacecraft structures such as solar power arrays, solar sails, antenna arrays, and drag sails; they have the potential to enable larger variants of these structures while reducing the packaging volume required. In this thesis, these methods are applied to the preliminary structural design of a space solar power satellite. This deployable spacecraft, measuring 60 m x 60 m, can be packaged into a cylinder measuring 1.5 m in height and 1 m in diameter. It can be deployed to a flat configuration, where it acts as a stiff lightweight support framework for multifunctional tiles that collect sunlight, generate electric power, and transmit it to a ground station on Earth.

Through Wafer 3D Vertical Micro-Coaxial Probe for High Frequency Material Characterization and Millimeter Wave Packaging Systems

This work presents the development of an in-plane vertical micro-coaxial probe using bulk micromachining technique for high frequency material characterization. The coaxial probe was fabricated in a silicon substrate by standard photolithography and a deep reactive ion etching (DRIE) technique. The through-hole structure in the form of a coaxial probe was etched and metalized with a diluted silver paste. A co-planar waveguide configuration was integrated with the design to characterize the probe. The electrical and RF characteristics of the coaxial probe were determined by simulating the probe design in Ansoft’s High Frequency Structure Simulator (HFSS). The reflection coefficient and transducer gain performance of the probe was measured up to 65 GHz using a vector network analyzer (VNA). The probe demonstrated excellent results over a wide frequency band, indicating its ability to integrate with millimeter wave packaging systems as well as characterize unknown materials at high frequencies. The probe was then placed in contact with 3 materials where their unknown permittivities were determined. To accomplish this, the coaxial probe was placed in contact with the material under test and electromagnetic waves were directed to the surface using the VNA, where its reflection coefficient was then determined over a wide frequency band from dc-to -65GHz. Next, the permittivity of each material was deduced from its measured reflection coefficients using a cross ratio invariance coding technique. The permittivity results obtained when measuring the reflection coefficient data were compared to simulated permittivity results and agreed well. These results validate the use of the micro-coaxial probe to characterize the permittivity of unknown materials at high frequencies up to 65GHz.

Standardised tobacco packaging:a health policy case study of corporate conflict expansion and adaptation

Objectives: To investigate opposition to standardised tobacco packaging in the UK. To increase understanding of how transnational corporations are adapting to changes in their access to policymakers precipitated by Article 5.3 of the Framework Convention on Tobacco Control (FCTC). Design: Case study web-based documentary analysis, using NVivo V.10. Examination of relationships between opponents of standardised packaging and transnational tobacco companies (TTCs) and of the volume, nature, transparency and timing of their activities. Setting: UK standardised packaging policy debate 2011-2013. Participants: Organisations selected on basis of opposition to, or facilitation thereof, standardised tobacco packaging in the UK; 422 associated documents. Results: Excluding tobacco manufacturing and packaging companies (n=12), 109 organisations were involved in opposing standardised packaging, 82 (75%) of which had a financial relationship with 1 or more TTC. These 82 organisations (43 actively opposing the measure, 39 facilitating opposition) were responsible for 60% of the 404 activities identified, including the majority of public communications and research production. TTCs were directly responsible for 28% of total activities, predominantly direct lobbying, but also financially underwrote third party research, communication, mass recruitment and lobbying. Active organisations rarely reported any financial relationship with TTCs when undertaking opposition activities. Conclusions: The multifaceted opposition to standardised packaging was primarily undertaken by third parties with financial relationships with major tobacco manufacturers. Low levels of transparency regarding these links created a misleading impression of diverse and widespread opposition. Countries should strengthen implementation of Article 5.3 of the FCTC by systematically requiring conflict of interest declarations from all organisations participating in political or media debates on tobacco control.

The sensory features of packaging and its effects on product perception

The present study shows the influence of tactile contacts with packaging on product taste. A within-subject experiment 1 (product: grenadine syrup) x 3 (packaging���s material: plastic, aluminium, glass) was conducted. Moreover, we examine the role of the Need For Touch (NFT) as a moderator. We confirmed that the same product tasted three times by each participant is judged differently depending on the packaging. Furthermore, participants with a high NFT seem to be more influenced by sensory features of packaging than those with a low NFT. These results support previous researches about tactile effects on taste.