| Lithography is an important step in the processes of preparing micro-nano devices and structure.Ensuring interface stability is a challenge to researchers because the factor of the interface damage are complex in lithography.In order to promote the adhesion between photoresist and substrate,the most common method are to heat the sample and use adhesion promoter to modify the surface,however,HMDS adhesion promoter is used to inhibit the adhesion of interface in the process of dry stripping or nanoimprinting,which causes researchers confusion and misunderstanding.The mechanical theory of interface damage has been well explained,but the complexity of interface composition cannot be fully explained by mechanical methods alone.More specific and convenient methods are still needed to analyze the interface damage behavior with complex boundary.With the wide application of nano-structured devices,the traditional etching method to control the interface damage cannot meet the diversified requirements of industrial for micro-nano structured devices.More and more researchers begin to explore new methods to realize the controllable application of interface damage.This thesis aimed to explain and control the interface damage behavior in lithography process,further illustrated the influence of interface characteristics on interface damage behavior through test and simulation verification,established a convenient and practical mechanical analysis method for bonding interface damage,and proposed the technological application of controllable interface damage.The main research contents are as follows:(1)The comparison methods of contact angle measurement,peel test and experiment were designed to prove that the main reason HMDS modification inhibited the delamination of photoresist in the development was that HMDS modification reduced the hydrophilicity of Si substrate and thus prevented the intercalation behavior of water molecules at the photoresist-substrate interface during the developing process.(2)A finite element analysis method based on cohesive zone model was established to analyze the damage behavior of interface during mechanical peeling process,and the constitutive relationship of interface adhesion was expressed by using cohesive zone model through uniaxial tensile test.The peel model established by this method had wide applicability and could simulate the peel at any angle from0° to 180° theoretically.(3)A controllable interface damage processing method of photoresist micro-nano structure was proposed.The method utilized HMDS modification to inhibit interface adhesion and combined with contour lithography technology to achieve selective stripping of photoresist structure.The mechanism of the process was analyzed by using the finite element analysis method based on the cohesive zone model,which helped to prove that the process was realized because of the enhancement of contour adhesion caused by lithography.At the same time,the mechanical stripping equipment was built to ensure the processing quality of the method.(4)A method for processing nanoscale gaps by coupling capillary force with interface damage was proposed.This method could break through the limits of lithography in this work and assemble nanoscale gaps by capillary force acting on micron structure.At the same time,a finite element simulation model was established to verify the experimental phenomenon and provide guidance for higher distinguishability machining methods under this method. |
