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Wetting and Spreading of Solder on PCB Surface
Wiesner, Lukáš ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
This work deals with the metal surface wetting problems of molten lead-free solder and monitoring of ongoing processes at the inter-phase interface. This work also deals with flushing monitoring of spreading velocity on solder finishes Ni/Au and Immersion Sn deposited on copper plated base material FR4 using digital cameras. Measurement is performed at the improved workplace. After the reflow process is measured by length of spreading solder. It evaluates and compares the time dependence of velocity of spreading solder for Ni/Au and Immersion Sn finishes.
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Lead-Free Voids Cause Mechanisms and Influence on Reliability
Šimon, Vojtěch ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
The aim of this work is to analyze reliability of lead-free solder join, in particular the voids generated during the soldering process. The main target of the theoretical part of the work is to isolate basic mechanisms of formation of the voids and optimize the soldering process. The practical part of the paper is based on monitoring the count and size of the voids in a solder join. An X-Ray tomograph has been chosen as a non-destructive method of detection. The statistical part of this work compares conventional soldering of the entire board with local soldering by IR radiation.
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Electrical and thermal characteristics of lead-free solder joints
Jurásek, Matěj ; Adámek, Martin (referee) ; Schnederle, Petr (advisor)
This wok is focused on the issue of soldering. The theoretical part describes the basic requirements for materials and solders alloys, which enter into this process. Further also factors that have a major impact on the quality of joints and methods, that are used for final testing of electrical and optical properties. The aim of the practical part of this work will be monitoring changes in electrical properties depending on the base material, surface finish PCB contact surfaces, the type of solder alloy and residual oxygen concentration in the atmosphere. The resulting values are compared, and they will draw the final recommendations for the method of soldering used alloys
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Cooling effect on growth of intermetallic compounds in lead-free solder joints
Faldyna, Martin ; Novotný, Marek (referee) ; Vaško, Cyril (advisor)
This work deals with issues of process optimalization of lead-free soldering. The aim of this work is demonstrate of cooling on grow intermetallic layers during lead-free solde ring process and a hold intensity of cooling on joint quality. The experiment was performed with two types of solder pastes: Sn/Ag/Cu a Sn/Bi/Zn. The final samples were appraised in light of wet-ting, size of intermetallic layers, optical estimation solder and sudar stress test.
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Solder Joint Conductivity - Influence of Solder Volume and Isothermal Aging
Mach, Ladislav ; Schnederle, Petr (referee) ; Starý, Jiří (advisor)
The master thesis analyses electrical conductivity of lead-free solder joints. The test method design for monitoring the electrical conductivity of the soldered joint is described in the practical part. Simulated BGA package with four pin (BGA4) is used for experiments. Tested PCBs are subjected to isothermal aging and current load. During isothermal aging is measured electrical conductivity and optical microscope is used for intermetallic layer (IMC) growth observation. Two types of surface finish (OSP and ENIG) are used for tests and three diameters of solder terminal balls (solder alloy SAC405). The influence of the ratio area connection / solder volume (ratio S / V) on lead-free solder joints conductivity was evaluated.
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Study of lead-free solder joints reliability
Pícha, Jan ; Starý, Jiří (referee) ; Szendiuch, Ivan (advisor)
The thesis deals with problems concerning lead free soldering especially the study of the structure of solder joints and their reliability. The thesis evaluates lead free solder alloys. The theoretical part includes basic principles of soldering and methods of investigating solder joints reliability. The experimental part deals with the impact of water cooling and vibration on solder joint structure. Both methods are tested and are evaluated with regard to their reliability. The used tests include X-ray inspection, optical inspection, mechanical tests, investigating joint structure with electrone microscope.
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Wetting and Spreading of Liquid Solder on Metal Surface
Kučera, Lukáš ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
This work deals with the metal surface wetting problems of molten lead-free solder and monitoring of ongoing processes at the inter-phase interface using the method of evaluation of the height of the molten solder deducted from the video sequences. The work is aimed at evaluating the metal surface wettability, wetting angle determined. Wettability of the metal surface is compared for different types of surface treatments and for different ages of the measured samples. Measurement is performed at the improved workplace, is used to evaluate the newly derived formula for calculating the wetting angle and created program for automatic evaluation of Picture is used to.
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Solder Joint Electric Conductivity and Solder Joint Reliability
Lačný, Radek ; Stejskal, Petr (referee) ; Starý, Jiří (advisor)
This work is considered about changes of electric conductivity in lead-free soldered joint's affected by current and thermal stress. The theoretical part describes factors influencing the solder joint electric conductivity and solder joint reliability. The basis of the practical part is the design of the testing method of the soldered joint's electric conductivity. The aim of this part is to measure and observe changes of solder joint electric conductivity after current and thermal stress in various material a procedural combinations.
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Advancing Packiging and 3D systems
Nicák, Michal ; Šandera, Josef (referee) ; Szendiuch, Ivan (advisor)
This project consists of three parts. The first part is aimed to summarize list of actual packaging systems and especially systems using 3D construction. Project continues in the second part, which is more practical and contains design and production of organic and inorganic testing substrates for lead-free soldered 3D structures. Last experimental part is about tests performed on soldered substrates and evaluation of results of these practical tests.
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Termodynamické re-modelování systému Cu-Ni-Sn
Zemanová, Adéla ; Kroupa, Aleš
The Cu-Ni-Sn system is an important alloy system in lead-free soldering. In the scope project COST 531 the binary data for the Ni-Sn system required modification. The high temperature form of Ni3Sn, which has a DO3 structure, was modeled as BCC_A2 in the COST 531 thermodynamic database for compatibility with Cu-Sn system. The reassessment of this phase was carried out with the help of Parrot module in the ThermoCalc software and very good agreement was reached comparing the partial quantities from previous data and new model of this phase. Nevertheless it was also necessary to remodel the description of the Cu-Ni-Sn ternary system. The reassessment was based on the work of Miettinen who was primarily concerned with copper-rich compositions and experimental data for lower temperature.
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