Fig. 1. (a) Geometry of the trapezoidal groove line grating; (b) layers division for inverse modeling based on RCWA.(a) 线条光栅结构的几何形貌示意图; (b) RCWA建模的分层示意图

Fig. 2. Principle and instrument of the dual rotating-compensator Mueller matrix ellipsometer: (a) Principle; (b) instrument.双旋转补偿器型Mueller矩阵椭偏仪　(a)基本光路; (b)仪器

Fig. 3. (a) The SiO₂ sample; (b) the PMMA sample spinning coated on the surface of the SiO₂ film. (a) SiO₂薄膜样品; (b) 在SiO₂表面旋涂PMMA光刻胶后的薄膜样品

Fig. 4. Extracted results of the thicknesses of SiO₂ film h₁ and equivalent surface roughness r₁: (a) r₁; (b) d₁; (c) MSE. 拟合得到的20组SiO₂膜厚d₁及其表面粗糙度等效膜厚r₁ 　(a) r₁; (b) d₁; (c) MSE

Fig. 5. Extracted results of the optical constants n₁ and k₁ of SiO₂ film calculated by Cauchy model and the ones from Ref. [34]: (a) n₁; (b) k₁. 拟合得到的第1, 5, 10, 15和20组SiO₂薄膜光学常数n₁和k₁的计算值, 以及文献[34]给出的折射率与消光系数　(a) n₁; (b) k₁

Fig. 6. Extracted results of the thicknesses of PMMA film d₂ and equivalent surface roughness r₂: (a) r₂; (b) d₂; (c) MSE. 拟合得到的20组PMMA膜厚d₂及其表面粗糙度等效膜厚r₂ 　(a) r₂; (b) d₂; (c) MSE

Fig. 7. Extracted results of the optical constants n₂ and k₂ of PMMA film calculated by Cauchy model: (a) n₂; (b) k₂拟合得到的第1, 5, 10, 15和20组PMMA薄膜光学常数n₂和k₂的计算值　(a) n₂; (b) k₂

Fig. 8. Geometry of the simulated PMMA grating samplePMMA光刻胶仿真光栅的结构示意图

Fig. 9. Fitting results of the calculated and the “ellipsometer-measured” Mueller matrix elements at the incidence and azimuthal angles fixed at θ = 65° and φ = 0°. 在入射角θ = 65°、方位角φ = 0°的入射条件下, PMMA光刻胶仿真光栅的模型计算Mueller矩阵光谱与“测量”光谱之间的拟合曲线