Polarimetry is a non-destructive technique that measures the degree of rotation of polarized light passing through an optically active material. Optical activity is determined by various factors, including intrinsic optical properties and residual stress. Thus, polarimetry can be used in various fields. In this study, polarimetry was used to evaluate the two-dimensional spatial uniformity of optical birefringence in an Ajinomoto build-up film. This analysis can predict the optimal cure condtitions of the film, which creates a uniform phase retardation distribution.