The project deals with the effect of the airflow and temperature on the gold wirebond due to possible application in hot-wire anemometry. Theoretical fundamentals of wirebonding and hot-air anemometry are included in the text. From the area of anemometry, there is also a detailed description of measurement principles, areas of application and measuring instruments. The practical part of the text deals with design of the experimental sensor for hot-wire anemometry with use of the gold wirebond, including also the verification of the sensor's properties.

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The thesis summarizes the basic knowledge of Wirebonding. It also closely studying the various influences on the final shape, strength and reliability of the bonds. In the experimental part are found the optimal settings of various wire bonders. For wire bonder TPT HB-10 are found the optimal settings for different types of surfaces, which were contacted.

With increasing miniaturization in microelectronics the wirebonds used in IC packages are witnessing a thrust towards fine pitch wirebonding. To have a precise control over loop height of the wirebond for fine pitch wirebonding, it is imperative to do mechanical characterization of the wirebond. The present work studies the mechanical properties of gold wire and wirebond using nanoindentation. The wirebond specimen surface was planarized using mechanical polishing. The loop height of the gold wirebond is directly proportional to the length of the heat affected zone (HAZ) above the ball of gold wirebond. Metallographic preparation of gold wirebond cross section reveals the presence of undesirable coarse grain structure in HAZ due to recrystallization and grain growth in the gold wire adjacent to the ball. The recrystallization temperature of our gold wire was found using D.S.C. to be 340.66°C. The doping elements present in the gold wire used, were identified using TOF-SIMS. Nanoindentation of the gold wire was done at different maximum loads to observe the hardness variation with load. The nanoindentation of gold wirebond has confirmed a v-shaped hardness profile in the HAZ. The hardness minima for the particular gold wire used with a ball size ratio of 2.4 was observed at distance of 160-170 µm from the neck of the ball. The elastic modulus was found to vary randomly and to be independent of the microstructure in the wirebond. A yield stress profile based on empirical hardness-yield strength correlation has been predicted for the gold wirebond. / Singapore-MIT Alliance (SMA)