利用純量繞射理論探討複合式菲涅耳波帶片之聚焦特性

Abstract

極紫外光微影術是下一世代微影技術可能的主流技術。在極紫外光的波段下，菲涅耳波帶片是非常重要的光學繞射元件之一。在固定孔徑大小以及製程極限下，具有中央擋片結構的菲涅耳波帶片不但能提供高空間解析度並且阻擋零階繞射光。若阻擋的面積越大，則空間解析度將變的更高，但同時光強則會變的更低。在這樣的結構中，空間解析度與光強是不可兼得的。在本文中，我們利用菲涅耳－克希荷夫繞射公式模擬了在極紫外光波段下共十五個不同堆疉波帶片結構，此結構分別是由增強波帶片和主波帶片所組成。我們發現這十五個結構中，有一組的空間解析度與光強相較於只具有中央擋片結構的波帶片還要來的更好。

Extreme ultraviolet lithography (EUV) is one candidate of the next generation lithography. In EUV wavelength, Fresnel zone plate (FZP) is one of the most important diffractive optical elements. In a fixed fabrication limit and lens size, Fresnel zone plate with a central stop can not only provide high spatial resolution but also block the zero order diffractive light. More area blocked in the center, higher spatial resolution can be achieved but accompanied with lower light intensity. It is trade-off between the spatial resolution and light intensity in this kind of structure. In this thesis, fifteen cases of stacked zone plate which are composed by an enhancing zone plate and primary zone plate are studied by Fresnel-Kirchhoff diffraction formula in EUV wavelength. One of the cases can not only improve the spatial resolution but also enhance the light intensity as comparing with only one zone plate with central stop.