Lithographic Pattern Quality Enhancement Of DMD Lithography With Spatiotemporal Modulated Technology

In the past few decades,with the rapid development of optical micro nano processing technology,maskless lithography based on digital micromirror device(DMD)has been widely concerned.DMD based maskless lithography has been widely used in many fields such as integrated circuit manufacturing,drug delivery,cell carrier,tissue engineering and so on because of its advantages of no mask,high lithography efficiency and low cost.However,the inherent microstructure of the digital micromirror device(DMD),that is,the square micromirror,will produce a pixel pattern.These pixel patterns will cause the position deviation and edge aliasing of the engraved microstructure,and reduce the quality of the engraved pattern.Low position accuracy and rough sawtooth edges cannot satisfy the increasing requirements of high-fidelity manufacturing of micro-devices,such as diffractive micro-optics.In order to solve this problem,we can use higher magnification projection objective lens for lithography,but this will greatly reduce the efficiency of lithography.Therefore,in order to solve these problems,a new lithography strategy,spatiotemporal modulation projection lithography(STPL)based on DMD,is proposed in this paper.This technology takes full use of the high-resolution PZS,flexible pattern generation of DMD as well as controllable light source.It can balance the manufacturing efficiency,the resolution,the cost and other factors.Carry out related work according to the above strategy:(1)In this paper,we proposed a novel STPL technology within conventional DMD based lithography system.Instead of using high magnification objective lens or relying on expensive high-resolution DMD,we creatively combined the fretting of piezoelectric platform(PZS),flexible pattern generation of DMD and exposure time.We use such a way to make up for the pixel effect brought by the DMD micromirror itself,making the lithography linewidth more accurate,the line position more accurate,and the line edge more fluent which is very effective for static exposure to improve the quality of arbitrary lithography patterns.The results of energy simulation and repeated experiments show that submicron microstructure can be prepared by this method.(2)The precision of microstructure manufacturing is limited by the inherent microstructure of the DMD,and the increasing requirements for high-precision manufacturing(such as diffractive micro-optics)cannot be achieved.This article proposes a new STPL technology.By using this technique,we can make Fresnel zone plate,which is a high fidelity diffractive lens with submicron line center position accuracy and greatly reduced line edge roughness.The edge sawtooth of the Fresnel zone plate fabricated by using the STPL is reduced to 0.3?m,the error between the actual measured linewidth and the ideal linewidth is only within ±0.1?m,and the focal length is 15 mm,which is basically consistent with the designed focal length.These results indicated that STPL can serve as a significant role in the micromanufacturing field for achieving high fidelity microdevices.