Research On The Anodic Bonding Process By Controlling The Bonding Current

Anodic bonding is one of the key techniques used in the micro electro mechanical systems(MEMS) industry for the packaging of pressure sensors, gyroscopes, accelerometer, micropumps and so on. As the anodic bonding process involves complex physical and chemical changes, any differences in the distribution of electrical and thermal fields along the bonding systems will cause significant influence on the performance of the MEMS devices. With the development of MEMS towards miniaturization and complication, it has become more and more urgent to find out a way to control such bad influence. As the bonding current is the macro-scene for the movement of ions in the glass and plays a significant role during the whole bonding process, a new approach by analyzing and controlling the bonding current to improve the bonding quality is put forward in this paper.In this paper, the mechanism behind the formation of the bonding current was analyzed and an electrical model for the bonding current was established. The relationship between the bonding parameters and the bonding current was obtained on the basis of the electrical model and verified by experiments, which provides a criterion for choosing and controlling the bonding current subsequently.Then the influence of the bonding current parameters on the bonding strength, including the current peak, the rate of decay and the holding time, was studied by a series of experiments. In the end, an orthogonal experiment was done with appropriate factors and levels and the support vector machine was chosen to established the process parameters model by analyze the experiment results. The prediction error of the model was checked by a series of single-factor experiments.