Defect detection in films on ceramic substrates

Abstract

Abstract Thin opaque or non-opaque films formed on a substrate (10) are inspected by utilizing the inherent fluoresceability of the substrate material. The filmclad substrate, e.g. ceramic, is illuminated with an intense optical radiation (18) consisting of at least one wavelength which corresponds to the excitation band(s) of the ceramic component responsible for fluorescence. For opaque films, the incident light will reach the ceramic in regions corresponding to the defects causing these ceramic regions to fluoresce at a different wavelength (20) than that of the incident light, thus providing a high contrast optical image of the defects particularly when viewed through a filter which transmits only the fluorescent radiation. For non-opaque films, the incident light will generate fluorescent radiation over the entire substrate. The fluorescent light emanating from the defective regions will be higher than that from the non-defective regions due to absence of any absorption of the incident and fluorescent light by the defective regions of the film.

Inventors

• 👤 Alexander Leon Flamholz

Bibliographic Details