Research On Mechanism And Method Of Anodic Bonding Between Metal And Glass

Anodic bonding is a process of joining glass to metal or semiconductor,which has the advantages of low bonding temperature,short bonding time,reliable and stable bonding.It is widely used in electronic technology,aerospace,biomedical and other fields,which is one of the key technologies of MEMS(Micro-Electro-Mechanical System)device packaging.With the development of packaging technology for MEMS devices,the market has put forward higher requirements for the performance of packaging materials.Therefore,it is of great significance to study the mechanism and process characteristics of metal-glass anodic bonding for the further development of MEMS packaging technology.Firstly,through the anodic bonding experiments of titanium alloy and glass under the conditions of bonding temperature of 300??400? and bonding voltage of 600V?900V,it was found that due to the migration of alkali metal ions,the glass formed Na+ depletion layer near the titanium alloy side under the action of the electric field.A large amount of non-bridged oxygen anions were enriched in the region,which reacted irreversibly with Ti on the surface of the titanium alloy to form Ti6O and formed a close connection between the titanium alloy and glass.With the increase of the bonding temperature and voltage,the peak value of the bonding current increases and the decay rate increases.The bonding strength test confirmed that the fracture occurred in the glass and the bonding interface was intact,and the bonding strength was over 10MPa.Next,the anodic bonding experiments of aluminum alloy and glass were carried out under the conditions of bonding temperature 250??300? and bonding voltage 700V?900V,it was pointed out that the diffusion of metal ions in the anode and oxygen anions in the cathode was the basic condition for the bonding of aluminum alloy and glass.The change rule of bonding current is obtained by establishing current-time model.It is found that the bonding current reaches a peak rapidly and then decays exponentially.The bonding strength of aluminum alloy and glass increases with the increase of the bonding temperature and bonding voltage,and reached 6.84 MPa at bonding temperature 300? and bonding voltage 900V.In the end,according to the theoretical model of laser-assisted anodic bonding between SiCp/Al and glass,the temperature field distribution on the bonding surface was simulated by finite element software,and the power range of laser-assisted anodic bonding was determined.The laser-assisted anodic bonding of SiCp/Al to glass was realized under the conditions of laser power 2W?3 W,scanning speed 5mm/s?10mm/s and bonding voltage 600V?800V.Then,the experimental design of laser-assisted anodic bonding between SiCp/Al and glass was carried out by response surface method.The mathematical model of process parameters and bonding strength was established.The influence of process parameters on bonding strength was analyzed.It was pointed out that the laser power had the most significant effect on bonding strength,followed by scanning speed and bonding voltage.Finally,the optimal process parameters are obtained by taking the maximum bonding strength as the optimization criterion.When the laser power was 2.71W,the scanning speed was 13.62mm/s,and the bonding voltage was 725.35V,the bonding strength could reach 6.96 MPa,which meet the strength requirements of MEMS device package.