In this thesis, the main investigation is focused on the design and fabrication of Re-distribution(RDL) in Wafer Level Chip Scale Package(WLCSP). As bumping process capability becoming more and more popular, WLCSP will be the main package trend for IC with lower pin count. Due to the high performance analog devices should be met more restricted requirements for electrical conductivity and higher electrical current passing by, hence the thick plating Cu is chosen for RDL and under bump metallization(UBM) for WLCSP package to meet both electrical and reliability requirements. The experiments discussed herein include: photo exposure DOE, adhesion DOE between 2ND PI and RDL and contact resistance DOE after post etching treatment. From the DOE results, we obtain the results as follows: The exposure dosage optimized by using 1.5X original parameter that can fix the photo resist residue problem. The key to the adhesion between PI2 and RDL is the curing temperature. Lower curing temperature 375¢J/320¢J provides better adhesion. O2/ CF4 treatments effectively increase contact resistance. However, O2/Ar¡BAr and O2 work much better than O2/ CF4 in increasing the contact resistance after surface treatment. The completion of this study could give some suggestions to the manufacturers of application of RDL WLCSP, furthermore, it shorten the development period to enhance the mechanical and electrical performances of products.

This thesis deals with the quantitative determination of bioaccessible contents of selected elements (Cu, Fe, Zn) in legumes: chickpeas, pea, lentil, soybean, bean. The UBM in-vitro test was used for the study of bioaccessible forms. This method simulates human digestion using synthetic gastric juices. Atomic absorption spectrometry was used for the determination of the total content of selected elements in legumes and their bioaccessible contents in gastric and gastro-intestinal human tract. The results showed that copper was the most bioaccessible from green lentils and chickpeas. The lowest bioaccessibility of copper was from soybean. The highest bioaccessibility of zinc was from green lentil, soybean, yellow pea and color bean, but the lowest bioaccessibility was from the black lentils. The best bioaccessibility was from all lentils whereas the lowest iron bioaccessibility was from soybean, yellow pea and color bean. The biggest differences between the gastric and gastro-intestinal phases were in green lentils, yellow peas and chickpeas, while the closest contents in phases were in both types of beans.

The work is aimed at determining bioaccessible mercury content of fish and fish products. In the theoretical part is described mercury, health risk, levels of mercury in food, descriptions of each species, fish consumption, chemical composition and nutritional importance of fish consumption, UBM method and methods for the determination of mercury. Firstly, in the practical part the total mercury contents were measured, then there was carried out the UBM test and finally, bioaccessible levels of mercury were analyzed. Analyzed samples of fish and fish products were purchased in the markets of Czech Republic. The analysis of mercury was performed by atomic absorption spectrometer AMA 254. Limits established by legislation (Commission Regulation (EC) No. 1881/2006 as amended) were exceeded in 11 samples. The lowest percentage of mercury bioaccessibility has been found in samples of frozen marlin and the highest percentage were measured at a sample of bigeye smoked tuna.

<p>Translesion synthesis (TLS) is a specialized type of DNA repair for bypassing DNA damage at the stalled replication fork. Because the TLS polymerases (mainly from the Y-family of polymerases) are characterized by more open active sites in order to accommodate the lesions, they are inherently more mutagenic than the replicative polymerases. Although essential for cell survival and in tolerating DNA damage, the access of the TLS polymerases to the replication fork must be tightly controlled. This regulation occurs in part through the ubiquitination state of the processivity factor PCNA. Damage-induced monoubiquitination of PCNA serves in part as the regulatory switch between replicative and translesion polymerases. Highly conserved ubiquitin-binding domains, the ubiquitin-binding zinc finger (UBZ) domain and the ubiquitin-binding motif (UBM), within the C-termini of the Y-family polymerases provide for an increased affinity of the polymerases to PCNA after damage to promote TLS. In order to determine the molecular basis for ubiquitin recognition by the TLS polymerases, we solved the solution structures of the human pol &#951; UBZ domain, the human pol &#953; UBM2 domain, and the human pol &#953; UBM2-ubiquitin complex. </p><p>The UBZ domain adopts a classical C2H2 zinc finger structure characterized by a &#946;&#946;&#945; fold, similar to the DNA-binding zinc finger proteins. Nuclear magnetic resonance titration mapped the binding interfaces between UBZ and ubiquitin to the &#945;-helix of the UBZ domain and the canonical hydrophobic surface of ubiquitin defined by residues L8, I44 and V70. Although the UBZ domain binds ubiquitin through a single &#945;-helix, in a manner similar to the inverted ubiquitin-interacting motif, its structure is distinct from previously characterized ubiquitin-binding domains. The pol &#951; UBZ domain represents a novel member of the C2H2 zinc finger family that interacts with ubiquitin to regulate translesion synthesis. </p><p>In contrast to the human UBZ domain, the yeast UBZ domain lacks one of the conserved cysteines necessary for zinc coordination, leading many to propose that it is a "zincless" zinc finger. We used biophysical methods to characterize the UBZ domains from human and yeast pol &#951; and to highlight differences between their structures and modes of ubiquitin binding. Like the human UBZ domain, the yeast UBZ domain binds zinc, which contributes to its secondary structure formation. In contrast to the human UBZ domain, the yeast UBZ domain binds to ubiquitin in a zinc-independent manner. Correspondingly, mutations in the zinc-coordinating residues of the yeast UBZ domain do not impair the polymerase's response to DNA damage.</p><p>We also investigated the structural elements and mechanism of ubiquitin recognition of the ubiquitin-binding motif (UBM) found in pol &#953; and Rev1. The solution structures of the C-terminal UBM of human pol &#953; and its complex with ubiquitin were solved. The UBM is a novel ubiquitin-binding domain that binds to the hydrophobic surface of ubiquitin centered at L8. Accordingly, mutation of L8A, but not I44A of ubiquitin abolishes UBM binding. Human pol &#953; contains two functional UBMs, both of which contribute to replication foci formation. In contrast, only the second UBM of <italic>Saccharomyces cerevisiae</italic> Rev1 binds to ubiquitin and is essential for Rev1-dependent cell survival and mutagenesis. Point mutations impairing the UBM-ubiquitin interaction also disrupt foci formation of pol &#953; and the DNA damage response of Rev1 <italic>in vivo</italic>, showing the significant role for the UBM in regulating TLS.</p><p>The structures of the UBZ domain and the UBM and their recognition of ubiquitin are different and distinct from other ubiquitin-binding domains. Their highly specific and unique associations with ubiquitin are critical for TLS regulation and further add to the diverse base of ubiquitin-binding domains and their role in mediating cellular functions.</p> / Dissertation

In this thesis, the residual stress distribution of metal film sputtered on silicon substrate are studied. The commercial Marc finite element method package is used in this work. The thermal-mechanical model is employed in the residual and thermal stress analysis of thin film during the sputtering process. Two models finite element are used in this study. One is the 2D axial-symmetric model and the other is the 3D. The 2D axial-symmetric model was employed to investigation the residual stress distribution in 4¡¨, 6¡¦¡¦, and 8¡¦¡¦ wafer during the UBM sputtering process. The 3D model was used to study the effects of sputtering parameters, i.e. sputtering temperature and film thickness, on the residual stress distribution. The effect of etching process on the sputtered film has also been studied by using the 3D model. Results indicate the proposed model can simulate the residual stress distribution successfully.

Hybrid pixel detectors are widely used in many fields, including military, environment, industry and medical treatment. When integrating such a detector, a vertical connection technique called flip-chip bonding is almost the only way to realize the high-density interconnection between each pixel detector to the read-out chip. Such bonding can offer high-density I/O and a short interconnect distance, which can make the resulting device show excellent performance. Electro deposition is a promising approach to enable a low cost and high yield bump bonding process, compared with conventional sputtering or evaporation which is currently utilized for small-scale production. Due to that, Indium bumping process using electroplating is selected, as a result of which indium bump arrays with a pitch of 220 μm and a diameter of 30 μm have been fabricated using a standard silicon wafer processing. UBM (under bump metallization) for indium bumping was Ti/Ni (300 Å/ 2000 Å). It helps to increase adhesion between the wafer and the bumps and also serves as an excellent diffusion barrier both at room temperature and at 200°C. The indium is electroplated, using an indium sulfamate plating bath, and then formed into bumps through a reflow process. The reflow is made on a 200°C hot plate with a continuous flow of nitrogen over the wafer. During the reflow the indium is melted and forms into bumps due to surface tension. All the corresponding procedural processing steps and results are incorporated in this paper.

This thesis presents the low cost process for UBM formation on aluminum pads of single die/dice for Flip Chip applications. The UBM (Under Bump Metallurgy) is required in solder bump structure to provide adhesion/diffusion barrier layer, solder wettable layer, and oxidation barrier layer between the bonding pads of the die and the bumps. Typically, UBM is deposited on the whole wafers by sputtering, evaporation, or electroless plating. These deposition techniques are not practical for UBM formation on single die/dice, thus preventing Flip Chip technology to be applied in applications where the whole wafers are not available. The process presented in this thesis has been developed to overcome this problem. The developed UBM formation process allows the UBM layer to be deposited on a single die, thus eliminating the requirement to have the whole wafer in the deposition process. With the combination of the UBM formation process developed in this work and a suitable bump formation technique, solder bumping on a single die can be achieved, thus making Flip Chip technology available for use in low volume applications and prototyping stages. The developed UBM formation process consists of two major steps; temporary die attach process and UBM deposition process. The first process is developed using thermoplastic adhesive film. The second process is developed using electroless nickel plating, followed by gold immersion. It has been demonstrated in this thesis that the developed process can be used to form the UBM layer on the die successfully regardless of the die size and the complexity of the die pattern, and that this process does not damage nor affect electrically the sensitive die. / Master of Science

In this paper SAM (self-assembled monolayers) is used to passivate cobalt microbumps for 3D-stacking of Si chips. The SAM deposition process is optimized, using input from characterization techniques such as water contact angle measurement, ATR, AFM and XPS analysis in order to form a monolayer of Thiols-SAM on cobalt microbumps. A 3D stacked Si chips test vehicle was used to demonstrate the effectiveness of the SAM coating on cobalt bumps by measuring the electrical continuity of daisy chains.

"The stiffness of scaffolds used in surgical ventricular restoration may play an important role in the degree to which they facilitate regeneration of functional cardiac tissue. The stiffness of the scaffold influences the phenotype of cells which are present in it as well as their ability to deform the scaffold. The goal of this study was to evaluate in vitro methods to characterize and alter the stiffness of new scaffold materials. Membrane inflation testing, an in vitro mechanical testing method, was evaluated in this study because of its ease of use and the similar mode of loading which it shares with scaffolds implanted in vivo. The structural stiffness of two scaffold materials, urinary bladder matrix and Dacron, were determined in vivo and using membrane inflation testing. Despite higher tensions and lower area stretch ratios for scaffolds tested using membrane testing, similar changes in structural stiffness between the two materials were found for both methods (5.6 ± 3.3 fold in vivo, 5.0 ± 1.0 in vitro). This finding demonstrated that membrane inflation testing is a useful in vitro method for measuring changes in structural stiffness between scaffold materials with a level of sensitivity similar to that which is measured in vivo. Membrane inflation testing was used to assess the effectiveness of altering scaffold stiffness through exposure to various cell culture conditions. Incubation of a biological membrane in cell culture media resulted in a drastic decrease in the elastic modulus from its initial value (3.55 ± 0.52 MPa) after 2 weeks (1.79 ± 0.30 MPa), 4 weeks (1.04 ± 0.09 MPa), and 10 weeks (0.014 ± 0.01 MPa). When fibroblasts were cultured on the scaffolds for 10 weeks an increase in elastic modulus (0.134 ± 0.05 MPa) over scaffolds incubated in culture media for the same amount of time was observed. The increase in elastic modulus due to the presence of fibroblasts was accompanied by an increase in the percentage of collagen in the samples (54.1 ± 5.1 % without fibroblasts, 83.2 ± 5.1 % with fibroblasts). Contrary to expectation, addition of ascorbic acid to the media to increase production of collagen by the fibroblasts resulted in a decrease in elastic modulus (0.030 ± 0.01 MPa) compared to scaffolds cultured with fibroblasts in standard media and a decrease in the amount of enzymatically degraded collagen (40.8 ± 4.7 % without ascorbic acid, 21.1 ± 3.3 % with ascorbic acid). Regeneration of cardiac tissue after a myocardial infarction is a complicated process which is influenced by a myriad of different factors. Future studies investigating the exact role which substrate stiffness has on regeneration will be essential to the development of improved cardiac scaffolds. Characterization of the stiffness of these scaffolds by membrane inflation and manipulation through exposure to cell culture conditions are powerful approaches to facilitate future studies."

Submitted by Marcos Samuel (msamjunior@gmail.com) on 2017-02-06T15:18:32Z No. of bitstreams: 1 Dissertação_Natalia_versaofinal_CD.pdf: 2740629 bytes, checksum: 2ad0d4cbbf049e9e14424691d159d518 (MD5) / Approved for entry into archive by Vanessa Reis (vanessa.jamile@ufba.br) on 2017-02-06T16:10:18Z (GMT) No. of bitstreams: 1 Dissertação_Natalia_versaofinal_CD.pdf: 2740629 bytes, checksum: 2ad0d4cbbf049e9e14424691d159d518 (MD5) / Made available in DSpace on 2017-02-06T16:10:18Z (GMT). No. of bitstreams: 1 Dissertação_Natalia_versaofinal_CD.pdf: 2740629 bytes, checksum: 2ad0d4cbbf049e9e14424691d159d518 (MD5) / A Unidade de Bombeio Mecânico (UBM) é um dos equipamentos mais utilizados na produção de petróleo. Ele sofre com efeitos de desbalanceamento devido às características das cargas aplicadas e aos desgastes mecânicos causados ao longo do tempo por conta do esforço repetitivo que exerce. O desbalanceamento dos equipamentos é um dos principais efeitos usualmente estudados pela academia e indústria em função do grande impacto que provocam na durabilidade dos equipamentos. Este trabalho propõe um sistema capaz de balancear dinamicamente uma UBM através de algoritmos embarcados no controlador lógico programável do inversor de frequência, utilizado no controle de UBMs automatizadas. Para a detecção do desbalanceamento, duas formas indiretas de avaliar esse efeito foram abordados: o Fator de Carga Cíclica (CLF – Ciclic Load Factor) e análise de vibrações, através da Transformada Discreta de Fourier, ambos utilizando a variável torque. O CLF foi o critério escolhido para validação experimental do sistema. Em uma abordagem convencional, o CLF é calculado a cada ciclo de bombeio, mas tal estratégia não permite a atuação para o controle instantâneo da velocidade, que deve ser baseado na minimização do CLF. Para tanto, este trabalho propõe a aplicação de conceito baseado em janela deslizante, permitindo o cálculo de CLF a cada nova amostra. Esta abordagem permitiu também superar as limitações encontradas nos sistemas de inversão de frequência necessários à implementação da solução proposta neste trabalho. A atuação no controle de velocidade do motor usado no sistema de bombeio mecânico naturalmente pode interferir a capacidade do sistema de bombeio. Uma avaliação dessa capacidade foi implementada de forma a demonstrar a aplicabilidade do método de controle de desbalanceamento. Os resultados alcançados mostram que o sistema desenvolvido é capaz de minimizar o CLF através de um controle de velocidade, essencialmente, sem perda na capacidade do sistema de bombeio. Os testes foram realizados em bancada e validados na planta disponibilizadas pelo Laboratório de Elevação Artificial da Universidade Federal da Bahia