模擬探討以減光-緣邊-外架型相移圖罩製備45奈米接觸孔與以散條提升28奈米線焦深

Abstract

本論文使用美國KLA-Tencor之光學微影模擬軟體ProLith v. 9.0，主要探討以減光-緣邊-外架型相移圖罩製備45奈米接觸孔與以散條提升28奈米線焦深。重要發現如下： 1. 製備45奈米二維接觸孔，使用本論文首創之減光-緣邊-外架型相移圖罩，並搭配圓環偏軸發光，焦深最佳，圖罩偏差增大因子亦維持近於1。此搭配缺點為照射劑量甚高，易造成側葉光強過強而顯影。 2. 製備28奈米一維線條，以正偏差法搭配緣邊式減光散條與中央式減光散條，提升焦深效果最佳，可改善禁止間距。正偏差法與加入側面式減光散條此二法對焦深提升有近似效果。由隙之空間影像觀察，當邊端效應產生之干涉波開始分離時，方可加入中央式減光散條，若干涉波尚未分離，加入中央式減光散條反而影響主線條空間影像，降低焦深。 3. 製備孤立線，不受半間距解像度通式R=k1λ/sinβ束縛，當NA=1.35，正偏差法可製備22與16奈米孤立線。若使用杜邦第二代濕浸式液體（折射率n=1.64），提高主線條透射度，NA放大至1.50，可製備12奈米與8奈米孤立線。

The lithographic simulation software of Prolith v. 9.0 from USA KLA-Tencor was used in this thesis. The main studies are fabrication for 45 nm contact hole by using attenuated-rim-outrigger phase shifting mask and increasing depth of focus (DOF) for 28 nm line by using scattering bar. Some important findings are reported as following: 1. The fabrication studies for 2-dimension 45 nm contact hole, using firstly reported attenuated-rim-outrigger phase shifting mask by this thesis, and combined with annular off-axis illumination, DOF was found to be the best, mask error enhancement factor can also be maintained nearly in 1. The shortcoming of this combination was very high exposure dose, easy to cause excessively strong sidelobe intensity, and therefore developed. 2. The fabrication for 1-dimension 28 nm line, the positive bias method combined with rim attenuated scattering bar (R-ASB) and center attenuated scattering bar (C-ASB), DOF increasing effect was found the be the best, forbidden pitches can be improved. The two methods which are positive bias and the adding of side attenuated scattering bar (S-ASB) have shown to have approximate effect to the DOF increase. By observation of aerial image from space, C-ASB can be added only when the interference waves formed by edge effect began to separate. If the interference waves have not yet separated, the adding of C-ASB will affect the aerial images of main lines instead, and DOF will be decreased. 3. The fabrication of isolated lines will not be hampered by the general formula of half pitch resolution (R=K1λ/sinβ). When NA was set as 1.35, 22 nm and 16 nm isolated lines can be fabricated by positive bias. If the Dupont second generation immersion liquid (refractive index n=1.64) is used, transmittance of main lines of attenuated phase shift mask raised, and NA enlarged to 1.50, 12 nm and 8 nm isolated lines can be fabricated.