Low-temperature Anodic Bonding Packaging Process And Experimental Research Based On Dielectric Barrier Discharge Activation

MEMS sensors have a very broad market prospect due to their small size,light weight,low power consumption,high reliability,high sensitivity,and ease of integration.Bonded packaging is one of the key links in the production process of MEMS devices.Among them,anodic bonding is most widely used in packaging;however,conventional anodic bonding requires high temperature,and the thermal stress failure caused by it becomes the anodic bond of high-performance MEMS devices.A major challenge in packaging,exploring how to reduce the anode bonding temperature has always been a research hotspot of this process.At present,the main ways to achieve low temperature anodic bonding are to adopt new matrix materials,improve bonding conditions and interface modification.Because the surface modification of plasma materials has the advantages of no pollution and high efficiency,it has become an important technical solution to achieve low-temperature anodic bonding interface modification in recent years.Based on this,in this paper,combined with the characteristics of dielectric barrier discharge(DBD)plasma that is easy to implement and easy to be compatible with the anode bonding process,a composite process method for low temperature anodic bonding based on dielectric barrier discharge activation is studied.Starting from the conventional anodic bonding mechanism,the anodic bonding realization mechanism is analyzed,the effect of the bonding temperature on the matrix ion movement and the formation mechanism of the surface bonding connection are discussed,and then the effect of temperature and surface properties on the anodic bonding is studied to obtain the surface properties Coupling relationship with bonding temperature;analysis of the mechanism of dielectric barrier discharge plasma activation on the surface of anodic bonding materials,combined with the formation mechanism of surface bonding connections,theoretically discusses the mechanism of low temperature anodic bonding.Then study the dielectric barrier discharge state at atmospheric pressure,use COM SOL Multiphsics to model and simulate the dielectric barrier discharge process,analyze the influence of the dielectric barrier discharge parameters on the discharge state,and find that the discharge gap has a significant effect on the distribution of the discharge electric field,especially when The effect is greater when the gap is reduced to the nanometer level.By modeling and analyzing the dielectric barrier discharge under the nano-gap,it is found that the electric field distribution of the discharge under the nano-gap is uniform,most of the space electric field strength is relatively low,it is easier to produce uniform discharge,and the distribution of electron energy density is more reasonable.Next,the effects of discharge parameters such as discharge voltage,discharge frequency,discharge gap,etc.on the bonding surface activation performance and bonding are analyzed through experiments.In order to verify the conclusion of the simulation that the activation effect under the nano-gap is better,a comparison test between conventional and nano-gap activation bonding was conducted,and it was found that the hydrophilic angle was significantly reduced after the dielectric barrier discharge activation,the surface performance was improved,and the bonding strength It becomes higher;the minimum temperature of anodic bonding can be reduced to 220? after activation by conventional dielectric barrier discharge,and the bonding temperature can be reduced to 200? after activation under nano-gap.When the bonding temperature is also 250?,the bonding strength after activation under the nano-gap is higher,up to 6MPa.Finally,based on the optimized low temperature bonding process method of dielectric barrier discharge,a test platform was built to verify and optimize the low temperature anodic bonding process based on nano-gap dielectric barrier discharge activation.After that,a single factor test was used to determine the parameter range of the discharge voltage and discharge frequency,and the optimal discharge voltage and discharge frequency were 2 kV and 10 kHz,respectively,characterized by the hydrophilic angle.On this basis,with the goal of lowering the bonding temperature,the bonding parameters were determined through a single factor test to complete the anodic bonding at a low temperature of 110 ?,and the bonding strength was 1.5 MPa.Finally,the analysis of the bonding current after activation explains the reason why the bonding can be promoted after activation from the perspective of current.