当具有足够大发散角的柱面光照射在匀厚金属薄膜表面时,由表面等离子体振荡产生的光反射率角分布是膜厚的函数,用CCD接收反射光分布信息并经过计算机分析处理,可实时、在线测量10nm内的铬、钛等金属膜厚,这类金属的复介电常数的实部相对虚部是较小的负数,故具有强反射锐峰及较平坦的吸收峰,该两峰点可作为膜厚测量依据的特征标记点,并通过建库进行曲线匹配而获得膜厚数值。实验结果表明,该方法的平均测量误差可低于0.4nm。 When cylindrical light having a sufficiently large divergence angle is irradiated on the surface of a uniform thickness metal film, the angular distribution of light reflectance caused by surface plasmon oscillation is a function of the film thickness. The CCD is used to receive reflected light distribution information and undergo computer analysis processing, Real-time, on-line measurement of 10nm within the chromium, titanium and other metal film thickness, the complex permittivity of the real part of the relative imaginary part of the smaller negative, it has strong reflection peak and relatively flat absorption peak, the Two peak points can be used as the film thickness measurement based on the characteristics of points, and by building a library curve matching to obtain the film thickness value. The experimental results show that the average measurement error of this method can be lower than 0.4nm.