Research On The Contact Characteristics Of Silicon-gold Interface In Anodic Bonding

Anode bonding technology is a semiconductor manufacturing method that combines silicon wafer and glass structure closely through chemical and physical actions.It has the advantages of low bonding temperature,firm bonding interface,long-term stability and so on.It is widely used in the fabrication of supporting structure of microsystem and the electrical connection between complex electrodes.The bonding quality depends on the contact state of the bonding surface,so the study of contact characteristics is of great theoretical value and engineering significance for the evaluation and optimization of bonding performance.In this paper,the silicon-gold contact interface in anodic bonding is taken as the object,and its bonding contact characteristics are studied from the aspects of theoretical analysis,modeling method,simulation and application.The main contents are as follows:1.Based on Hertz contact theory,the mechanical model of elastic-plastic contact on rough surface is established,and the condition of plastic deformation is analyzed.The contact area and contact force of single rough peak under elastic contact and plastic contact are calculated.On this basis,the contact area and contact force of two random rough surfaces are deduced.2.The contact resistance calculation method under different contact conditions is introduced in detail,and an accurate micro contact resistance model is established according to the actual contact radius of silicon-gold contact.On the premise of known contact area,the upper and lower limits of contact resistance of a single rough peak in elastic contact and plastic contact are calculated,and then the upper and lower limits of contact resistance of two random rough surfaces are derived.3.According to the surface roughness of silicon wafer and gold electrode,the corresponding Gauss rough surface is constructed,and the surface is reconstructed by reverse engineering technology.The reconstructed surface is imported into the Workbench to establish the contact finite element model of silicon-gold-glass surface.By applying displacement to simulate the contact process of rough surface,the research on the contact characteristics of silicon-gold under the coupling of structure field and electric field is completed,and the change of ohmic contact resistance during the contact process is analyzed..4.Taking the bonding structure of micro-accelerometer as the object,the silicon-gold contact resistance is measured by experiment,and compared with the theoretical value and the finite element simulation value,which verifies the correctness of theoretical analysis.Finally,the influence of contact resistance on the output signal of micro-accelerometer is analyzed.