采用梯形棱镜波前分割的激光干涉光刻技术

光学光刻技术在微细加工和集成电路(IC)制造中一直是主流技术。随着IC集成度的提高,要求越来越高的光刻分辨力,但光学光刻的分辨极限受光刻物镜数值孔径(NA)和曝光波长(λ)的限制。激光干涉光刻技术具有高分辨、大视场、无畸变、长焦深等特点,其分辨极限为λ/4,在微细加工、大屏幕显示器、微电子和光电子器件、亚波长光栅、光子晶体和纳米图形制造等领域有广阔的应用前景。阐述了激光干涉光刻技术的基本原理。提出了一种采用梯形棱镜作为波前分割元件的激光干涉光刻方法。建立了相应的曝光系统,该系统可用于双光束、三光束、四光束和五光束等多光束和多曝光干涉光刻。给出了具有点尺寸约220nm的周期图形阵列的实验结果。

Laser Interferometric Lithography with Wavefront Divided by a Trapezoidal Prism

In the optical microfabrication and integrated circuits(IC) manufacturing,optical lithography is a long main technology.According to the demand of high data density of IC devices,higher photolithography resolution is required.The resolution of optical lithography is limited by objective lens NA of the imaging system and wavelength λ of the exposure source.Many resolution enhancement techniques(RETs) are being studied by IC researchers worldwide.Laser interferometric lithography with high resolution,large field of exposure,distortionless and longer depth of focus has resolution limit of λ/ 4,and has many applications in the fields of optical microfabrication,large sized flat panel displays,microelectronic and optoelectronic devices,subwavelength gratings,photonic crystals,nanostructure manufacture,and so on.In the paper the principles of laser interferometric lithography is proposed which utilizes a trapezoidal prism as a wavefront division device.An exposure system for experiment research is established which can be used in double-beam,triple-beam,four-beam and five-beam,single- and multi-exposure laser interferometric lithography,Also given is the experiment result which shows a periodic dot array of photoresist dot size~220nm.