User-defined Microstructures Array Fabricated By DMD Based Multistep Lithography

Spatial light modulator-based projection lithography has attracted widespread attention as it is an efficient manufacture technology with the soaring requirements of optical precision devices currently.As a representative example,digital lithography based on digital micromirror devices?DMD?due to the flexible pattern generation of DMD,provides rapid processing speed and has been extensively utilized in microelectromechanical systems?MEMS?,microoptoelectromechanical system?MOEMS?,microfluidic processing etc.Although DMD digital lithography technology has the advantages of high digitization,high flexibility and low cost,the lithography product is limited by the period of the DMD's micromirrors because of the static exposure of conventional DMD based lithography system.In this case,the spatial distribution and the size of the lithography product can only be integer multiples of period of the DMD's micromirrors,which greatly limits the flexibility of DMD digital lithography.Therefore,this dissertation conducts relevant research on the above issues and proposes a new developed DMD based multistep lithography?DMSL?,which combines the dose modulation,the high-resolution movement of PZS,and the flexible pattern generation of DMD.Carry out related work according to the above strategy:?1?Aiming at the issue that the spatial distribution of the lithography product is constrained by DMD period,the dot matrix with user-defined period is taken as an example for illustration.For any preset lattice,a mathematical model N₁×d=N₂×D is established.By adjusting the initial pattern for DMD and the displacement of PZS,arbitrary periodic lattice can be obtained after multiples exposures.The periodic microstructures with different hexagonal periods?3 ?m,3.5 ?m and 4 ?m?are realized under the guidance of the above theory.Furthermore,dots matrix with subpixel resolution is realized by combining with the dose modulation.?2?Aiming at the problem that the size of the lithography product is limited by the period of DMD,the fabrication of microstructures array with user-defined shape are taken as examples.The spatial distribution of the array is determined by the initial pattern of DMD,and the shape of the microstructure is adjusted by the moving trajectory of PZS.The strategy is demonstrated through software simulation and actual lithography.The user-defined linear / curve periodic / non-periodic microstructures arrays are fabricated,which verifies the practicability and superiority of the above-mentioned lithography strategy.