FLEXIBLE COPPER-CLAD LAMINATES

摘要

A flexible copper-clad polyimide laminate is provided to estimate the residual stress due to thermal or physical causes of a polyimide layer by measuring a refractive index and to secure excellent dimensional stability without curl by reflecting the refractive index during a polyimide laminate manufacturing process. In a flexible copper-clad polyimide laminate having a polyimide layer on at least one surface of a copper-clad, a refractive index(Deltan) of the polyimide layer measured by an optical microscope and calculated by a formula of Deltan=Rlambda/d is 0.130~0.165. R is a natural number. lambda is a wavelength of a light source. d is the thickens of a film. A residual stress value of the polyimide layer is estimated by measuring a refractive index of a polyimide film, and curls and dimensional stability of the polyimide laminate at high temperature are estimated by using a refractive index value of the film.