Chip tilting and silicon cratering were compared for the two modes of thermosonic flip-chip bonding. Finite element model (FEM) using ANSYS? was used to study the effect of rigidity of transducer and the stress induced on the silicon layer during bonding . There are three problem areas in ultrasonic bonding: bonding energy transform, bond process control and bond quality monitoring. The main concern in wire bonding technology is the difficulty in transducer design, monitoring and influencing the bond quality during the bond process, and theories and attempts to solve this problem are as old as the technology itself [4-9].
In the age zero defect manufacturing, electronics manufacturing engineers are seeking the best solution based on more reliable statistical data and analysis on bonding dynamics [10-15], e.
g. the sensor configuration and properties had been studied in , the modeling and simulation for a transducer with flange constraints had been presented in , the characteristics of the longitudinal-complex transverse bonding system was studied by  and the piezocomposite driver for transducer had been mainly investigated by Or et al. ; they have all contributed to obtaining a best solution for system design.It is universally acknowledged that when ultrasonic energy removes brittle surface oxide in the beginning phase of bonding processes, the structure of the crystal lattice on the new bare metal surface is incomplete, then one material atom begins to transfer Carfilzomib another material.
Some bonder manufacturers have suggested that the cleaning phase requires more power than the mixing phase.
The bondability as a function of the ultrasonic power-vs-time profile needs to be studied. The best built-in sensor for ultrasonic vibratory energy will work for monitoring the ultrasonic power directly. The objective of this research was to understand the bond process by monitoring the effect of input power on its performance. Eleven Brefeldin_A groups of bonding data at different energy level settings (both successful and unsuccessful) were studied seeking a relation between bondability window and input power.
A Laser Doppler Vibrometer was used to record the structural response and to explain the phenomena occurring in the experiments [16-19]. The high vibration frequency of the transducer is proven by process tests to be effective to achieve robustness and to improve the ball roundness [16,17]. This not only benefits the fine pitch of wire bonding capabilities, but also decreases the minimum wire bonding temperature required for the applied bonding force. Currently, the longitudinal working frequency is up to 200 kHz .