No description available.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Microelectronic wire bonding is a manufacturing process used to electrically connect integrated circuits with circuit boards or other substrates. Conventionally, balls are molten at the end of a Au bonding wire and subsequently bonded on Al metallization of a integrated circuit. However, Pd/Ni metallization has recently been used for its improved mechanical properties. The bondability, bonding mechanism, and reliability of Au ball bonds on Pd are studied in this thesis. The substrates were produced in this project using three different materials. The base material is polished Cu in the shape of a coupon (1.0 cm × 1.0 cm × 0.5 mm). Cu coupons are plated with Ni (1.0 μm) using an electroless process, followed by electrolytic plating of a layer of Pd (0.3 μm), resulting in an arithmetic mean roughness of the surface of 0.08 μm (baseline sample, sample 0). Higher roughness values of 0.2, 0.4, and 0.5 μm are artificially produced by rolling (sample 1), sanding (sample 2), and sandblasting (sample 3), respectively, on the Cu surface before plating Ni and Pd. A 25 μm diameter Au wire is used for bonding on the polished and roughened substrates with a process temperature of T = 220 °C, and it was found that ≈ 4 % to ≈ 18 % less ultrasonic amplitude was required for successful bonding on the roughened substrates compared to the polished substrate. Bondability is measured by shear testing the ball bonds. An average ball bond strength achieved on the polished substrate is 130 MPa. This value is lower on the roughened substrate with the exception of the sandblasted substrate. Long-term thermal aging at 250 °C was performed with ball bonds on samples 0-3 for durations of ≈ 300 h. The reliability of the bonds is characterized by non-destructive contact resistance analysis during aging and destructive cross section analysis after aging. Contact resistance values for the ball bonds range from 1.6 to 3.5 mΩ at 20 °C before aging, and does not correlate with roughness. For the baseline sample, contact resistance of the ball bonds decreases during aging by -6 % (median value), which indicates electrical integrity of the interconnections at high temperature. This decrease possibly is due to interfacial gap filling by Au or Pd diffusion. In contrast, the contact resistance increases for the roughened samples 1-3 and changes are 0.4, 5, and 14 %, respectively (median values). A conclusive explanation for this increase has not yet been found. After 250 h of aging, a TEM analysis showed Au to Pd diffusion in the baseline sample with a diffusion depth of ≈ 0.1 μm Au. No intermetallics, voids, or contamination is found on the interfaces after aging according to nanohardness, SEM, and TEM analyses. No bond lift-offs or electrical opens were found for the aging temperature and durations chosen. No conclusive evidence for the presence of Au-Pd intermetallics or voids is found.

Microelectronic wire bonding is a manufacturing process used to electrically connect integrated circuits with circuit boards or other substrates. Conventionally, balls are molten at the end of a Au bonding wire and subsequently bonded on Al metallization of a integrated circuit. However, Pd/Ni metallization has recently been used for its improved mechanical properties. The bondability, bonding mechanism, and reliability of Au ball bonds on Pd are studied in this thesis. The substrates were produced in this project using three different materials. The base material is polished Cu in the shape of a coupon (1.0 cm × 1.0 cm × 0.5 mm). Cu coupons are plated with Ni (1.0 μm) using an electroless process, followed by electrolytic plating of a layer of Pd (0.3 μm), resulting in an arithmetic mean roughness of the surface of 0.08 μm (baseline sample, sample 0). Higher roughness values of 0.2, 0.4, and 0.5 μm are artificially produced by rolling (sample 1), sanding (sample 2), and sandblasting (sample 3), respectively, on the Cu surface before plating Ni and Pd. A 25 μm diameter Au wire is used for bonding on the polished and roughened substrates with a process temperature of T = 220 °C, and it was found that ≈ 4 % to ≈ 18 % less ultrasonic amplitude was required for successful bonding on the roughened substrates compared to the polished substrate. Bondability is measured by shear testing the ball bonds. An average ball bond strength achieved on the polished substrate is 130 MPa. This value is lower on the roughened substrate with the exception of the sandblasted substrate. Long-term thermal aging at 250 °C was performed with ball bonds on samples 0-3 for durations of ≈ 300 h. The reliability of the bonds is characterized by non-destructive contact resistance analysis during aging and destructive cross section analysis after aging. Contact resistance values for the ball bonds range from 1.6 to 3.5 mΩ at 20 °C before aging, and does not correlate with roughness. For the baseline sample, contact resistance of the ball bonds decreases during aging by -6 % (median value), which indicates electrical integrity of the interconnections at high temperature. This decrease possibly is due to interfacial gap filling by Au or Pd diffusion. In contrast, the contact resistance increases for the roughened samples 1-3 and changes are 0.4, 5, and 14 %, respectively (median values). A conclusive explanation for this increase has not yet been found. After 250 h of aging, a TEM analysis showed Au to Pd diffusion in the baseline sample with a diffusion depth of ≈ 0.1 μm Au. No intermetallics, voids, or contamination is found on the interfaces after aging according to nanohardness, SEM, and TEM analyses. No bond lift-offs or electrical opens were found for the aging temperature and durations chosen. No conclusive evidence for the presence of Au-Pd intermetallics or voids is found.

This thesis provides the design process for a new tooling ball detection method to calibrate moulds in automatic TIG welding. A mechanical component is designed to locate the tooling ball and convert the position information into analog signals. An electrical component is designed to process signals from the mechanical component and achieve the signal communication process. Finally, the computational component is designed and programmed to receive bits from the electrical component and convert information into position values for the tooling ball. The homogeneous transformation process is mathematically modeled for position computation in a robot system. The method is significantly different from current methods that have been developed and applied. Firstly, it uses a mechanical-touch style operation to locate the tooling ball with only a one-time detection operation. Secondly, it introduces a new approach for utilizing the joystick. Rather than as a manually operated direction controller for mobile control of devices, the joystick is used as a passive detection angle sensor. In order to properly use the joystick as an angle sensor, the joystick calibration method is also designed and tested. The designs of the three components are all implemented and tested separately. The results of these tests prove the feasibility of the new detecting method; however, the accuracy of detection is not yet acceptable and further improvements need to be made. In addition, a vision-based detecting method is also discussed at the end of the thesis. Compared to mechanical touch-style detection, the vision-based detecting method is designed to obtain better performance in a high temperature environment and to automate the tooling ball detecting process.

The purpose of this study is to investigate the impact effect of varied structure of golf ball. The researcher applied finite element analysis software LS-DYNA to do nonlinear impact analysis of different golf ball models. It was hoped that this study could design a better golf ball for golfer. The researcher had developed ten stress versus strain curves of two-piece golf balls (including a core and a cover) and three-piece golf balls (including a core, an inner cover and a cover) and four different thicknesses of inner cover of three-piece golf balls. The simulation also adjust the density of inner cover to analyze the impact procedure under the definite weight. With the special design of two-piece balls and three-piece balls, the impact models extract the ball velocities, and angular velocities for the calculation of the ball flight. Finally, the researcher made suggestions for some combination of material property and thickness of the core and the inner cover of the golf ball for the designer to develop a suitable golf ball.

Abstract In order to understand ball motions of new ultra-precision ball grinding machine, this study presents an mechanical model using a transparent acrylic container to simulate ball motions. The effects of float material, load, and process condition on the ball grinding characteristics at low shaft speed. The ball motions can be observed by the CCD camera to calculate the ball¡¦s circulation speed , the ball¡¦s spin angular speed and the ball¡¦s spin angle . Furthermore, the kinematic equations of ball motion is derived with different rolling sliding condition. The theoretical values of , , and are compared with the experimental values under pure rolling condition. Results show that the theoretical values are in good agreement with the ball¡¦s spin angular speed, but with larger error for and .This error is still in range of engineer error. Hence, at low shaft speed, contacts between balls and container, or shaft or float are close to the pure rolling conditions. Because the higher friction force between ceramic balls and alumina float, the ball¡¦s circulation speed with alumina float than that with acrylic float since fluid thrusts balls at low shaft speed, the ball¡¦s circulation speed in working fluid than that without working fluid. Since mass of float is light, it can be drive easily. Hence, with increasing the load which also increases the float mass, the float angular speed is decreased and the ball¡¦s circulation speed is also decreased.

This report was produced at the request of ABB Robotics and the work was conducted at their facilities in Västerås, Sweden. In the development of industrial robots the structures are slimmed to increase the accuracy and speed. When conducting finite element analysis on the robots the accuracy of the component modelling and definitions of the boundary conditions becomes more important. One such component is the ball bearing which consist of several parts and has a nonlinear behavior where the balls are in contact with the rings. The task given was to develop new methods to model roller bearings in Siemens finite element modelling software NX Nastran. Then conduct a strain measurement, to compare the methods to real experimental values. The goal with the report is to find one or more methods to model roller bearings, with accurate results, that can beused in their development work. The report was conducted by first doing a study on bearings and finite element modeling, and learning to use the software NX Nastran. Then the development of the methods were done by generating ideas for bearing models and testing them on simple structures. Nine methods was produced and a tenth, the method used to model bearings today, was used as a reference. The methods was used to build bearing models in a finite element model of a six axis robot wrist. Simulations were done on the models with different load cases and the results were compared to a strain measurement of the wrists real counterpart. Only six of the models were analyzed in the result, since four of the models returned results that were deemed unusable. When compiling the result data no model was found to accurately recreate the stresses in every load case. Three methods, that allow deformation, performed similarly. One of them is suggested to be used as modelling method in the future. Worst of the methods, according to the results compiled, was found to be the method used today. It fails to describe local stresses around the bearing. For continued work it is suggested that linear contact elements is studied further. Four out of five models constructed with linear contact elements failed to return satisfactory results.

This thesis provides the design process for a new tooling ball detection method to calibrate moulds in automatic TIG welding. A mechanical component is designed to locate the tooling ball and convert the position information into analog signals. An electrical component is designed to process signals from the mechanical component and achieve the signal communication process. Finally, the computational component is designed and programmed to receive bits from the electrical component and convert information into position values for the tooling ball. The homogeneous transformation process is mathematically modeled for position computation in a robot system. The method is significantly different from current methods that have been developed and applied. Firstly, it uses a mechanical-touch style operation to locate the tooling ball with only a one-time detection operation. Secondly, it introduces a new approach for utilizing the joystick. Rather than as a manually operated direction controller for mobile control of devices, the joystick is used as a passive detection angle sensor. In order to properly use the joystick as an angle sensor, the joystick calibration method is also designed and tested. The designs of the three components are all implemented and tested separately. The results of these tests prove the feasibility of the new detecting method; however, the accuracy of detection is not yet acceptable and further improvements need to be made. In addition, a vision-based detecting method is also discussed at the end of the thesis. Compared to mechanical touch-style detection, the vision-based detecting method is designed to obtain better performance in a high temperature environment and to automate the tooling ball detecting process.

No description available.