Confined Electrochemical Etching Micro-nanomachining Technology And System For Microlens Array

With the development of high technology, micro/nanotechnologyproducts such as microelectronics products and micro-electromechanicalsystems (MEMS) have been played an increasingly important role in thehuman’s life and industrial production. Their common feature is that thestructural or functional dimensions are in the range of micrometer ornanometer. Therefore, their processing methods are different from theconventional mechanical processing methods, which is called micro-nano-fabrication technologies. Traditional micro-nanofabrication techniquessuch as lithography, ultra-precision machining methods and the three-beamdirect writing process can only process the shape characteristic of2or2.5dimension size, which have their own limitations in machining three-dim-ensional(3D) complex micro-and nano structures. Recently, manufacturingmicro-nanostructure using electrochemical methods is a new developmentderection. Electrochemical machining method has many advantages suchas the ability to process a wide range of materials, stress-free, high surfacequality, high resolution and lower cost. This method has proven to havegreat potential in processing complex three-dimensional micro andnanostructures in the near future.In this paper, we studied the constraints electrochemical etchingmethod for micro-nanofabrication, focused on the two processing methodsnamed constraints etchant layer technique (CELT) and electrochemical wetstamping technology (E-WETS). Analysed the basic characteristics andrequirements of the processing equipment of the two methods. Then, we developed a high-performance micro-electrochemical nanofabricationsystem with nanometer resolution positioning accuracy based on that.Finally, the etching experiments was carried out on this system specificallyto fabricate the microlens array on the p-Si and GaAs substrate using CELTand E-WETS technique. achieved a high-precision optical microlens arrayby these replication process. The main results are as follows:Designed a high-performance micro-electrochemical nanofabricationsystem with nanometer resolution. Designed and optimized the marblearch bridge structure, improved the stiffness and reliability of the system;using the macro-micro complex motion as driving part of the system,five-phase stepping motor as the driving element of macro positioningplatform, cross the ball rail as a guide platform; Using piezoelectricceramic(PZT) with a fine movement stage drive element of the flexiblehinge as guide to achieve micro positioning; using S micro force sensor asa system detecting element to realized closed loop motion control.designed a three-DOF adaptive flexible leveling mechanism for thetemplate and the substrate inter-leveling, established a model of staticstiffness leveling mechanism, and finite element analysis to verify thevalidity,which can improve the processing results accuracy and consisten-cy effectively.Wrote the LabVIEW control program to realize the automatic control.The software includes: macro moving control module, micro movingcontrol module, approaching module, constant force control module anddata display and status indicator module. The software has a simpleinterface and easy to operate. Proposed a new approximation based on thedigital lock-in amplifier with high precision contact detection algorithmFocused on the problems of the contact detection of the template and thesubstrate in CELT. the contact detection process can be realized in thenanometer range; Achieved a constant force control algorithm for theconstant force control problems in E-WETS. the contact force is limited tothe size of the set value, with error less than0.2mN by the force feedback control.Carried out the related experiments on the instruments developed insthpiust tperaipnegr,. Tsehlee ncmt;ei tdch roeBl mrens array pattern is etched in the GaAs substrateusing the PMMA temp2late and CELT method. Including the PMMAand NaBr and electrolyzed etchant precursorspecies, L-cystine as the capture agent. Etching system for the selectionand optimizatioicrolens array pattern is etched on p-Si substrateusing E-WETS, and the agarose gel template production method has beendescribed. the electrochemical etching pattern is polished to obtain amicrolens array pattern which have a high surface finish.