Dual-Wavelength Method For Measuring The Thickness Of Hsq Photoresist

The reflectivity of thin film changes periodically with the increase of its thickness. According to this effect, we present a dual-wavelength method for measuring the thickness of HSQ film. At first, the refractive index of HSQ was measured by a spectroscopic ellipsometer. Then the relationship between the thickness of HSQ and the reflectivity was deduced. At last, the thickness of HSQ was calculated using the reflectivity measured by a spectrograph. The method was proved to be simple and effective.