Analysis of charge space distribution influence on electric adhesion forces

Abstract

Modeling ideas of physical and chemical processes when using an anodic bonding for materials connection are developed. The kinetics of a charge accumulation in an electrode region in a dielectric is considered. The thickness of a charge layer, electric fields strength and value of the ponderomotive pressure providing connection of materials are calculated. It is shown that the necessary ponderomotive pressure resulting in a dielectric-to-conductor seal is normally about ten megapascal and the time required is about ten minutes. The appearance of great pulling electric fields at anodic bonding process with a conductor surface to dielectric turns out to be possible due to the interlayer polarization developing in dielectric under the action of electric voltage. This results in a negative charge accumulation in a layer of small thickness beside anode. Thus applied electric voltage is distributed not through the whole thickness of a dielectric, but in fact is applied to a narrow area of the three-dimensional charge be-side anode. Arising strong electric fields force the connected materials to unite. The physical and mathematical models for force characteristics of non-uniform electric field are developed. Dependences of parameters of anodic bonding junction on time are considered. The expressions allowing to choose well-founded time of formation of anodic bonding junction are obtained, intensity of electrostatic fields and forces in dynamics is calculated. Research of a charge intermittence influence on electrostatic field strength has shown a considerable differences on small distances to the charged surface between carried out and traditional ways of calculation.