嵌附調細式相移光罩之研製與模擬

Abstract

嵌附調細式相移光罩因製作、缺陷檢查及修補等技術與傳統光罩相似，故 近年來深受半導體界重視。此式光罩目前有導電性較差及可見光之透光度 較大等缺點。本論文重點在發展新型嵌附調細式相移光罩相移層材質。研 究發現︰ 1. TiNx在薄膜厚度為83∼153奈米，相移角度為180度時，對 i-線透光度為5%∼11%，此時可見光透光度為18%∼39%。薄膜透光度 可由改變薄膜成份組成，而改變其透光度範圍。薄膜具導電性，比 電組約為0.052Ω-cm。此TiNx薄膜缺點為不具抗酸鹼能力。 2. TiSix在 薄膜厚度為83奈米，相移角度為180度時，對i-線透光度為2%，此時可見 光透光度為14%，比電阻約0.01Ω-cm，且此薄膜具抗酸鹼能力。 3. TiNx 與TiSix薄膜組合使用，可相互彌補缺點，使薄膜具抗酸鹼能力；導電性 亦佳；使薄膜之透光度較具變化的彈性；減低反光度及可見光透光度；並 對i-線透光度影響不大。此種組合較單一材質更適合相移光罩相移層使用 。 4. 模擬調細式相移光罩搭配環形偏軸發光，可改善0.35微米密集線/ 隙與孤立線圖案的解像度與聚焦深度。本論文初步改善了國外報導使用其 他材質應用於嵌附調細式相移光罩相移層材質之缺點。本論文相關題目值 得繼續深入研究。 The fabrication, defect inspection and repair of an embedded attenuated phase shift mask (EAPSM) are nearly identical to the conventional mask,therefore,EAPSM gained much attention from semiconductor industry. Currently,the disadvantages of EAPSM are having the lower conductance and too hight of transmittance to visible light, etc. In this thesis, study on the materials for phase shifter in EAPSM is emphasized. The results are reported as follows: 1. TiNx with thickness 83∼153 nm and degree of phase shift 180°,its transmittane to i- line(365nm)is in the range of 5∼11%, to visible light, 18∼39%. By changing the composition of this thin film, the range of transmittance could be altered. TiNx shows conductivity, with a specific resistance 0.052Ω-cm. The disadvantage of this film is the lack of resistance to acid and base. 2. TiSix with thickness ∼83 nm and degree of phase shift 180°, its transmittance to i-line is∼2%;to visible light,∼14%. TiSix shows a specific resistance of 0.01Ω-cm. This thin film is capable of resistance to acid and base. 3. The combination of TiNx and TiSix could remedy each other' disadvantages,making film with resistance to acid and base;with better conductance;with flexibility of changing transmittance; with reducing reflectivity and visible light transmittance; also,making the effect on i-line transmittance rather small. This combination of these two materials is more suitable to use as the a phase shifter of EAPSM than single material. 4. Simulation study on the attenuated phase shift mask with off- axis illumination together, the resolution and depth of focus for 0.35 μm dense line/space and line isolated could be improved.