This master´s thesis deals with bismuth low temperature solder pastes. Describes the properties of bismuth solder pastes. It shows the process of manufacturing a printed circuit board for test. The thesis also characterizes laboratory temperature profile setting for the BiSn soldering pastes. Solder paste printing and placement 0 ohm rezistors to printed circuit boards with different surface finishes in the manufacturing plant. Setting of solder profiles for low soldering pastes in reflow oven. Testing resistence of mounted zero resistor on the test board at different aging temperature were analysed. Resistance measurement after a specified time. Testing of solder joint strenght of printed circuit boards for different surface treatments. Changes in structure wereanalysed on microsections for solder pastes.

This graduation thesis addresses questions to thermal profile measurement of PBGA package during solder reflow process. The first part of thesis deals with problem of reflow process and reliability factors of solder joint connection. Next part analyses operation principles of thermocouples that are commonly used for temperature measurement. The experimental part deals with methods of thermocouples fixation during tests and measurements of dummy PBGA package. There was realized a method of dummy PBGA thermal profiles measurement and sample testing with and without simulated thermal load on PBGA package. The end of thesis concerns on possibilities of thermal profiles evaluation by using PWI method and thermal profile optimization of reflow process.

The project contains theoretical research of electrotechnical manufacture for lead-free reflow soldering. It contains characterization of soldering processes. Includes variations of solder paste printing, principles of part placing and also reflow soldering process. The project appoints possibilities of testing solder joints strength, mainly focused on mechanical vibrations. It describes a design and preparation of solder joint strength test methods by mechanical vibrations. It compares influence of vibrations on part types and solder alloys.

The Master thesis deals with technology of mounting QFN packages on to the printed circuits boards. Describes also influence of shape and size of soldering pads and the amount of soldering paste with respect to the quality and the reliability. In first part overview of existing packages is summarised. Second part describes design of testing board and the factors which leads to eliminating errors during manufacturing process.

No description available.

<p>Cilj: Kod trećine bolesnika sa akutnim ST-eleviranim infarktom (STEMI) nakon primarne angioplastike (pPCI) razvije se postinfarktno remodelovanje leve komore (LK). Cilj istraživanja je nalaženje ranih prediktora post-infarktnog remodelovanja leve komore nakon akutnog STEMI i pPCI. Metodologija: Uključeno je 210 ispitanika sa prvim akutnim STEMI prednjeg zida, lečenih pPCI. Urađena je ehokardiografija u prva 24h, a zatim nakon 6 meseci, kada su ispitanici podeljeni u 2 grupe: ispitivanu sa remodelovanjem (n=55; 26%) i kontrolnu bez remodelovanja (n=155; 74%). Ispitanici su klinički praćeni godinu dana. Rezultati i dikusija: Multivarijantnom regresionom analizom, kao najsnažniji rani prediktori post-infarktnog remodelovanja izdvojili su se: postojanje &quot;no reflow&quot; fenomena nakon pPCI (OR=30.0 95% CI, p&lt;0.0001), pojava dijastolne disfunkcije u prva 24h (OR=27.7 95% CI, p&lt;0.0001), povećan dijametar leve pretkomore - LA (OR=5.0 95% CI, p=0,044) i srčana slabost na prijemu - Killip klasa 2-4 (OR=3.4 95% CI, p=0.003.). Univarijantnom regresionom analizom, snažni prediktori su neadekvatna rezolucija ST segmenta - STR (OR 2.0 95% CI, p=0.024) i zbirni indeks zidne pokretljivosti &ndash; WMSI &gt;2 (OR 21.6 95% CI, p&lt;0.0001). Totalno ishemijsko vreme nije imalo uticaja na post-infarktno remodelovanje (p=0.546). Tokom jednogodi&scaron;njeg praćenja ispitanici sa post-infarktnim remodelovanjem su imali značajno veću incidencu glavnih neželjenih kardiolo&scaron;kih događaja: rehospitalizacija (61.8% vs 22.6%; p&lt;0.0001) / najvi&scaron;e rehospitalizacija zbog srčane slabosti (40% vs 2.6%; p&lt;0.0001), sa mortalitetom 5.5%/; reinfarkta (20% vs 7.1%; p=0.007); rekoronarografija (45.5% vs 18.1%; p&lt;0.0001); revaskularizacija (30.9% vs 11%; p=0.001). Zaključak: Kod pacijenata sa akutnim STEMI prednjeg zida lečenih pPCI, pojava &quot;no reflow&quot; fenomena, dijastolne disfunkcije, povećana LA i srčana slabosti na prijemu su najjači rani nezavisni prediktivni faktori za nastanak post-infarktnog remodelovanja. Značajni prediktori su i neadekvatna STR i WMSI&gt;2. Pacijenti sa post-infarktnim remodelovanjem imaju veću incidencu glavnih neželjenih kardiolo&scaron;kih događaja i mortaliteta.</p> / <p>Objective: Patients with ST-elevated myocardial infarction (STEMI) treated by primary angioplasty (pPCI) will develop left ventricular (LV) remodeling in one third of the cases. The purpose of this study is to determine early predictors of LV remodeling after acute STEMI and pPCI. Methods: 210 patients with a first acute anterior STEMI treated by pPCI were included. All participants underwent echocardiography in the first 24hrs and again after 6 months, after which they were divided into two groups: remodeling (n=55; 26%) and nonremodeling (n=155; 74%). Results and discussion: The most powerful independent early predictors were: &quot;no reflow&quot; after pPCI (OR=30.0 95% CI, p&lt;0.0001), diastolic dysfunction in the first 24hrs (OR=27.7 95% CI, p&lt;0.0001), increased diameter of the left atrium - LA (OR=5.0 95% CI, p=0.044) and at admission Killip class 2-4 (OR=3.4 95% CI, p=0.003), by multivariant regression analysis. Also, strong predictors were incomplete ST-resolution - STR (OR 2.0 95% CI, p=0.024) and Wall motion score index - WMSI &gt;2 (OR 21.6 95% CI, p&lt;0.0001), by univariant regression analysis. Total ischaemic time had no influence on LV remodeling. The group with remodeling had more frequent major adverse cardiac events (MACE) during one year follow-up: re-hospitalisation (61.8% vs 22.6%; p&lt;0.0001) / mostly re-hospitalisation due to heart failure (40% vs 2.6%; p&lt;0.0001) and mortality 5.5%; reinfarction (20% vs 7.1%; p=0.007); recoronagraphy (45.5% vs 18.1%; p&lt;0.0001); revascularisation (30.9% vs 11%; p=0.001). Conclusion: For the patients with a first acute anterior STEMI, treated by pPCI, development of &quot;no reflow&quot; after pPCI, diastolic dysfunction, increased LA and heart failure on admission are the most powerful early independent predictors for LV remodeling. Incomplete STR and WMSI&gt;2 are strong predictors too. Remodeling patients will have a more frequent incidence of MACE and mortality.</p>

Le développement à grande échelle des microbatteries pour des applications diverses comme l’alimentation de secours de certains composants électroniques dans les téléphones portables nécessite une compatibilité avec le procédé de solder-reflow employé dans le domaine de la microélectronique. Dans ce contexte, cette étude porte sur la mise au point d’un nouveau procédé de réalisation de couches minces d’oxysulfures de titane lithiés (LixTiOySz) pour une utilisation en tant qu’électrode positive dans une microbatterie Li-ion. Tout d’abord ce travail a débuté par la synthèse et la caractérisation de plusieurs compositions de sulfures de titane lithiés à l’état massif par réaction en solution de TiS2 ou TiS3 avec le n-butyllithium mais aussi par réaction à l’état solide à haute température entre les précurseurs TiS2, Li2S et Ti. Par la suite, des couches minces de LixTiOySz ont été déposées par pulvérisation cathodique radiofréquence à effet magnétron de cibles réalisées à partir des matériaux lithiés à l’état massif. La composition chimique de ces dépôts dépend de celle de la cible utilisée ce qui permet d’obtenir des couches plus ou moins riches en lithium et en soufre. En revanche, elles sont toutes très mal cristallisées, denses et elles ne présentent pas de structuration particulière. Enfin, les caractérisations électrochimiques des dépôts de LixTiOySz, à la fois en électrolyte liquide et solide, ont permis de mettre en évidence une corrélation entre leur composition chimique et leur comportement électrochimique. Globalement, ces dernières sont performantes, compatibles avec le solder-reflow et donc tout à fait intéressante pour l’application. / Large-scale development of microbatteries for various applications such as back-up power sources for cell phone electronic components needs suitability with reflowing process that is often used in microelectronic. Here we report on the development of a new realization process to produce lithiated titanium oxysulfides (LixTiOySz) thin films for use as positive electrode in Li-ion microbatteries. First of all, this work began with synthesis and characterization of several lithiated titanium sulfides compounds prepared by reaction between TiS2 or TiS3 with n-butyllithium but also by solid state reaction at high temperature between TiS2, Li2S and Ti. Then, LixTiOySz thin films were sputtered by magnetron effect radio-frequency sputtering from targets made of lithiated materials previously synthesized. The chemical composition of those films depends on the target one and allows obtaining thin films with different lithium and sulfur contents. In contrast, they are all amorphous, dense and they don’t have a morphological structuration. Finally, electrochemical characterizations of thin films, both in liquid and solid electrolyte, have highlighted a correlation between their chemical composition and their electrochemical behavior. Taken as a whole, LixTiOySz thin films are powerful, suitable with reflowing process and thus very interesting for the application.

Over the past 50 years, electronics manufacturing industry has undergone revolutionary changes, which have provided consumers with a plethora of electronic products. The increase in functionality of electronic products and decrease in cost due to continuous miniaturization and lower manufacturing costs have evolved over time. As electronics manufacturing technology becomes more advanced, reliability of electronic products and devices have become more of a concern. Thermomechanical reliability in electronics is studied in this research. Thermomechanical failures are failures due to temperature loading conditions electronic products and devices experience during manufacturing and service. The thermomechanical issue studied in this research is the effect of convective solder reflow on the warpage of packaged electronic devices, bare boards and chip packages. A convective reflow-projection moir warpage measurement system is designed and implemented in this research. The system is the first available system capable of measuring warpage of printed wiring boards (PWBs) with and without electronic components during simulated convective reflow process. A finite element prediction tool is also developed to predict the warpage of PWBs populated with plastic ball grid array (PBGA) packages. The developed warpage measurement system as well as the developed finite element model is used to study various PWB assembly (PWBA) configurations during simulated convective reflow processes.

Out-of-plane displacement (warpage) is one of the major thermomechanical reliability concerns for board-level electronic packaging. Printed wiring board (PWB) and component warpage results from CTE mismatch among the materials that make up the PWB assembly (PWBA). Warpage occurring during surface-mount assembly reflow processes and normal operations may cause serious reliability problems. In this research, a convective reflow and projection moire warpage measurement system was developed. The system is the first real-time, non-contact, and full-field measurement system capable of measuring PWB/PWBA/chip package warpage with the projection moire technique during different thermal reflow processes. In order to accurately simulate the reflow process and to achieve the ideal heating rate, a convective heating system was designed and integrated with the projection moire system. An advanced feedback controller was implemented to obtain the optimum heating responses. The developed system has the advantages of simulating different types of reflow processes, and reducing the temperature gradients through the PWBA thickness to ensure that the projection moire system can provide more accurate measurements. Automatic package detection and segmentation algorithms were developed for the projection moire system. The algorithms are used for automatic segmentation of the PWB and assembled packages so that the warpage of the PWB and chip packages can be determined individually. The effect of initial PWB warpage on the fatigue reliability of solder bumps on board assemblies was investigated using finite element modeling (FEM) and the projection moire system. The 3-D models of PWBAs with varying board warpage were used to estimate the solder bump fatigue life for different chip packages mounted on PWBs. The simulation results were validated and correlated with the experimental results obtained using the projection moire system and accelerated thermal cycling tests. Design of experiments and an advanced prediction model were generated to predict solder bump fatigue life based on the initial PWB warpage, package dimensions and locations, and solder bump materials. This study led to a better understanding of the correlation between PWB warpage and solder bump thermomechanical reliability on board assemblies.

The Square Kilometre Array (SKA) is known to be the most powerful radio telescope of its type. In support of its high observational power, it is estimated that thousands of antenna unit equipped with millions of LNA (low noise amplifier) will be deployed over a large area (radius>3000km). The stringent requirements for high performance and low cost LNA design bring about many challenges in terms of material growth, device fabrication and low noise circuit designs. For the past decade, the Manchester group has been wholeheartedly committed to the research and development of high performance, low cost Monolithic Microwave Integrated Circuit (MMIC) LNA with high breakdown (15V) and low noise characteristics (1.2dB to 1.5dB) for the SKA mid-frequency application (0.4GHz to 1.4GHz). The on-going optimisation of current design is hindered by the restriction of standard i-line 1µm gate lithography. The primary focus of this work is on the design and fabrication of new, submicron gate InGaAs/InAlAs/InP pHEMTs for high frequency applications and future SKA high frequency bands. The study starts with the design and fabrication of InGaAs-InAlAs pHEMT sub-100nm gate structure using E-Beam lithography. To address the problems of short channel effect and parasitic components, devices with 128nm T-gate structure, and with optimised device geometries and enhanced material growth, having fT of 162GHz and fmax of 183GHz are demonstrated, outlining the importance of device scaling for high speed operation. In addition, a gate-sinking technique using Pd/Ti/Au metallisation scheme was investigated to meet the requirement for single voltage supply in circuit design. Device with Pd-buried gate exhibits enhanced DC and RF characteristics and showed no degradation over 5 hours’ annealing at 230˚C. The implementation of this highly thermal stable Pd Schottky gate is key to improving the device’s long-term reliability at high-temperature operation. To solve the problem of low productivity in E-Beam lithography, a simple, low cost, technique termed soft reflow was introduced by utilising the principle of solvent vaporisation in a closed chamber. It provides a hybrid solution for the fabrication of submicron device using low cost i-line lithography. The integration of this new soft reflow process with the Pd-gate sinking technique has enabled the large-scale fabrication of 250nm T-gate pHEMTs, with excellent fT of 108GHz and a fmax of 119GHz and with device yields exceeding 80%. This novel soft reflow technique provides a high yield, fast throughput, solution for the fabrication of submicron gate pHEMT and other ultra-high frequency nanoscale devices.