Jakawat Deeying. Optimization of process parameters in lead-free solder jet bonding using laser to increase the shear strength of solder joint in HGA. Doctoral Degree(Industrial Engineering). King Mongkut's University of Technology North Bangkok. Central Library. : King Mongkut's University of Technology North Bangkok, 2019.
Optimization of process parameters in lead-free solder jet bonding using laser to increase the shear strength of solder joint in HGA
Abstract:
This paper aims to investigate the effect of laser solder jet bonding parameters to the solder joints in Head Gimbal Assemblies. Laser solder jet bonding utilizes Laser energy source directed through a fiber laser to melt a solder ball in a capillary prior to ejection. The molten solder is transferred/expelled to two bonding pads by nitrogen gas. The response surface methodology is used to investigate the effects of laser energy, wait time, nitrogen gas pressure, and focal position on the shear strength of solder joints. Also change to the change of pitch static attitude (PSA) must be controlled minimizing the change. The response surface methodology is employed to establish the reliable mathematical relationships between the laser soldering parameters and desired responses. Then, multi-objective optimization is conducted to determine the optimal process parameters that can enhance the joint shear strength and minimize the change of PSA. The validation test confirms that the predicted value has good agreement with the actual value.