| Ultrasonic bonding, as a technology of microelectronic pakaging,has been used widely, but the mechanism of bonding and process of the joining are controversial all the time. With the development of the electrocal device, there are many new problems. So the study of the ultrasonic bonding is significant.The aim of the investigation is to optimize the ultrasonic processing parameters and supply the experiment data.This paper investigated the width of joint and interficial resistance in experiment, analysed the data by Minitab and got 3D surface plot. The effects of process parameters on the bonding quality were studied. Simultaneously, those crytic influencing factors were also investigated. Totally speaking, the thesis includes the following parts:(1) DOE(design of experiment), Al+1%Si wire with 25μm diameter and three kinds of pads (Au/Ni/Cu pad , Cu pad and Ni/Cu pad) were bonded and the data were got. The data were analysed and fitted. The effects of the parameters (ultrasonic power, bonding time and bonding force) on the formation of joint and interfacial resistance were studied. Processing parameters were also optimized.(2) The tendency of the joining interface was studied with development of the parameters. To certify the rationality, the wire of joint aged was uncovered and compared to the chemical method to uncover the wire. The bonding mechanism was investigated for the factors.(3) The test circuit of interficial resistance was designed. As the variable , The parameters was used to analyse the tendency of interficial resistance. The factors were investigated by the curve of resistance.From the results of the experiment, it is indicated that the hardness of the pad plays an important role on the bonding. There are three kinds of models of failures, and they were relative to parameters. The factors of resistance take mutual action.
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