鉬矽氧嵌附式減光型相移圖罩之研製與模擬

Abstract

嵌附式減光型相移圖罩為重要解像度增進技術之一，本論文重點在研究適用於微影波長193 nm之嵌附式減光型相移圖罩MoSiO材質，探討在不同的成膜方式下，對光學、化學性質的影響。 正規嵌附層MoSiO薄膜在濺鍍成膜時，改變通入氧氣流量，可得符合嵌附層之需求。此薄膜於微影波長193 nm之折射率為1.813，吸收係數為0.35，符合相移角度180度之薄膜厚度計算值為118.69 nm；另成膜方式為MoSi薄膜加以氧電漿改質，通入氧氣時間不同，光學性質亦不同，符合嵌附層之微影波長193 nm折射率為1.637，吸收係數為0.527，符合相移角度180度之薄膜厚度計算值為151.49 nm。 由於嵌附層表面不似鏡面光滑平坦而產生散射光，導致所量測的反射率、透射率較真實為低。本論文修正反射率、透射率再應用於反射率-透射率法，所得之折射率與吸收係數較接近商業儀器n＆k分析儀量測出的值，證明此修正之價值。 以電子能譜化學分析儀與傅利葉轉換紅外光譜儀對薄膜進行分析，發現薄膜內二氧化矽與三氧化鉬成份增加時，折射率增加，吸收係數減少，有良好之化學組成與光學性質之關聯性，實際上薄膜之相互鍵結關係相當複雜，尚無法證實其對細部變化的影響。 模擬結果顯示，以傳統鉻膜圖罩搭配偏軸二孔發光於248 nm微影時，可成功製作0.115 μm密集線隙，且對於焦深與製程寬容度具較佳之改善效果。

Embedded Attenuated Phase-Shifting mask (EAPSM) is one of the important resolution enhancement techniques. The main point of this thesis is to study MoSiO which is material for EAPSM in 193 nm lithography, the effects of various ways of film growth on its optical and chemical properties. By changing the O2 flow rates in sputtering conditions, qualified MoSiO embedded layer could be obtained. Under 193 nm, refractive index of this film is 1.813, and absorptivity is 0.35, calculated thickness of this film which has a degree of phase shift 180 is 118.69 nm; in other different way of film preparation, MoSi film was treated with O2 plasma, the flow of oxygen also changed the property. For the qualified MoSiO film for 193 nm lithography, refractive index is 1.637, and absorptivity is 0.527, calculated thickness of this film which has a degree of phase shift 180 is 151.49 nm. The scattering light was generated from the surface of embedded layer which was not like a mirror, resulted in the facts that the measured reflectance and transmittance were smaller than its real reflectance and transmittance. The modified the R-T Method was used to determine n and k, and the values closed to the n and k measured by n＆k analyzer, so the value of modified method has been proved. Using ESCA and FT-IR to analyze MoSiO film, the increasing contents of SiO2 and MoO3 will increase n and decrease k. Therefore, the chemical compositions and optical properties are well correlated, however, their detailed correlations can not be verified. The result of simulation showed that traditional COG assisted with OAI dipole could fabricate 115 nm dense line in 248 nm, the DOF and process window were also improved.