鉻矽氮類嵌附式減光型相移圖罩之研製與模擬

Abstract

本論文重點在於研究適用於193與248奈米波長微影用嵌附式減光型相移圖罩之新嵌附層材質Cr-Si-N薄膜。研究結果發現： 1. Cr-Si-N薄膜可藉由改變濺鍍條件而得到符合嵌附層的需求。此薄膜於248奈米波長之折射率為2.41，吸光係數為0.47，符合相移角度180度的薄膜厚度之計算值為88.26奈米，此時的透射率為9.57%，反射率為18.76%；於193奈米波長之折射率為2.61，吸光係數為0.54，符合相移角度180度的薄膜厚度之計算值為59.94奈米，此時的透射率為8.84%，反射率為23.13%。 2. 以Cl2/O2為蝕刻氣體的進行活性離子蝕刻(RIE)，利用田口法規畫蝕刻實驗，得知最佳蝕刻選擇比為Cr-Si-N：阻劑＝6：1，Cr-Si-N：SiO2＝38：1。結果顯示薄膜蝕刻選擇比適合製備圖罩圖案。 3. 由於Cr-Si-N薄膜於檢測、對準用可見光波長處之透射率高於40%，通常可加上一層薄鉻膜降低透射率，亦可增加導電度。Cr-Si-N具有良好之抗酸性與照射穩定性。 4. 透射率與反射率的修正可使R-T 方法所計算之n、k值在學理上更為接近實際之數值，但本論文無法以VASE或其他方法驗證。

The main purpose of this thesis is to study the Cr-Si-N as a new embedded layer in EAPSM for 193 and 248 nm lithography. The results are as follows: 1. By changing the sputtering conditions, suitable Cr-Si-N embedded layer could be obtained. Under 248 nm, refractive index of this film is 2.41, and extinction coefficient is 0.47, calculated thickness is 88.26 nm for 180 degree of phase shift, its transmittance at this thickness is 9.57%, and reflectance is 18.76%; under 193 nm, refractive index of this film is 2.61, and extinction coefficient is 0.54. Calculated thickness is 59.94 nm for 180 degree of phase shift, its transmittance at this thickness is 8.84%, and reflectance is 23.13%. 1. Using C12/ O2 as RIE etchant, and using Taguchi method to design etching experiments, the best etching selectivity of Cr-Si-N：resist is 6：1, of Cr-Si-N : SiO2 is 38 : 1. These results show that the selectivity of this film is suitable for mask patterning. 3. Due to the transmittance of Cr-Si-N in visible wavelength which is for inspection and alignment is higher than 40%, in general, a thin Cr film could be added to decrease transmittance, its conductance is also increased. Cr-Si-N has good acid resistance and exposure durability. 4. The corrections of transmittance and reflectance can make the calculated n、k from R-T method closer to their real value, however, this thesis can't verify real value with VASE or other methods.