Principal Component Analysis Transducer System And The Bonding Point Of The Interaction Law

This paper is about the study of main factors in bonding process.A number of experiments were carried out at different power setting and temperature.Vibration velocity signal at the tip of transducer and its driving voltage, current were monitored. The length of minor axis and major axis for the gold balls was obtained. Amplitude at the tip of transducer, its driving electric power and area of the gold balls were calculated. The bonding strength was also evaluated. Above 9 parameters were analyzed by Principal Component Analysis (PCA).Three main factors can be obtained and their physical meaning was discussed. This paper included the following:Initially, it was found that the influence laws of one parameter on bonding strength, amplitude at the tip of transducer and its driving driving voltage, current and power is not the same when other parameter is changed.Additionally, the mechanism of PCA was explained and the PCA subroutine for Matlab was compiled to analyze above parameters.The results show that the first three principal components contain nearly all variability so that the following principal components could be ignored.The first three principal components are the expression of three main factors in bonding process.The first principal component can be regarded as the expression the factor of characterization for transducer. The temperature is characterized by the second principal components.The third principal component can be regarded as the interaction between the characteristic of bonding pad and ultrasonic transducer system.Finally, the parameters at different bonding period were analyzed PCA. The results showed that the loading and stationary period are more suitable for PCA.This research could provide reference for realizing bonding progress and understanding bonding mechanism.