Research On The Formation Mechanism Of Optical Thin Film Defects

With the rapid development of science and technology, research anddevelopment of films are widely used in optics, machinery, electronics, chemicals,printing, medical, aerospace and other fields. A variety of new functional devicesproposes a severe challenge on the film preparation technology. But the varioussurface defects met in film production process have serious impact on its function,and increase greatly the film producing cost.In this work, we introduce the film crack defect met in the preparation of aninfrared film product, by studying the forming mechanism of film stress, and makingthe optimization experiment from the material, temperature, transition layer and otheraspects, finally found the suitable material and process parameters, and solve theproblem of film crack, while the spectrum meets customer requirements, makinginfrared film products to volume production.Meanwhile, we have studied in the forming mechanism of common macroscopicnodule inclusions defect, and focus on improving nodule defect caused by splatteringdot, the suitable handling methods and pre-melting parameters are found by makingcomparative experiment on selecting material, handling, pre-melting and optimizingprocess parameters, greatly reducing the splattering dot proportion, and the productyield can be increased dramatically.Finally, we introduce the massive defect and strip defect, massive defect isconfirmed as a kind of hole defect (film empty hole), which is controlled mainly insubstrate cleaning and environment. Strip defect has a strange shape (defined as Pscratch), investigating the correlation between P scratch and glass substrate/ionsource/halogen lamp/coating material and so on, test and analysis the shape andcomponent of P scratch by FE SEM, and find the forming reason of P scratch. Bypurifying SiO2material, fully pre-melting material, optimizing deposition parametersand so on, P scratches defect decreased significantly, which change the view thatlooking purely for cause from physical point.