The work deals with research and development of a new method for ball-attach process, resp. reballing process of solder bumps on package with solder ball terminals (BGA, CSP, SOP, etc.), based on research and optimization of the parameters of the final terminals. The output is specially modified templates designed for placement of solder balls before reflow soldering. Three materially different templates were investigated in the work, in addition to the commonly used stainless steel, two other newly designed templates, which used ceramic materials (96% Al2O3a AlN) with thick-layer resistance heating. Proven advantages of the method using templates directly heated by electric current are the reduction of the thermal load of BGA packages in the first soldering process, as well as the creation of a better connection between the metallization of the case and the solder ball after final soldering to the printed circuit board. During the research, development and optimization of the method, tests of the created solder bumps were performed from the point of view of mechanical strength and internal structure. In the next part of the work, a research of solder bumps soldered using infrared heaters was performed in order to determine the influence of the heat flow direction in the process of reflow soldering. The heaters were successively placed in three positions, i.e. heating from the bottom of the housing, heating from the top and both heaters simultaneously. After sample preparation, metallographic cuttings and etching, the analysis of the internal structure of the entire solder ball and the intermetallic layer at the interface of the solder and the solder pad was performed. The work represents not only a new method of soldering solder bumps, but also new knowledge to create their internal structure, which contributes to meeting the increasingly demanding requirements to achieve the required reliability and quality.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:432558 |
| Date | January 2020 |
| Creators | Otáhal, Alexandr |
| Contributors | Pietriková,, Alena, Blecha,, Tomáš, Szendiuch, Ivan |
| Publisher | Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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