The standard "GB/T 14847-2010 Infrared reflection measurement method for film thickness of lightly doped silicon epitaxial layers on heavily doped substrates" specifies a method for measuring the film thickness of lightly doped silicon epitaxial layers on heavily doped substrates by infrared reflection technology. This method is suitable for silicon epitaxial layers with substrate resistivity less than 0.02Ω · cm and epitaxial layer resistivity greater than 0.1Ω · cm, and the epitaxial layer film thickness is more than 2μm. In the case of reducing accuracy requirements, this method is also suitable for epitaxial layers with film thickness ranging from 0.5μm to 2μm. The standard is designed to provide an accurate measurement technology to meet the needs of high accuracy semiconductor manufacturing.