単層薄膜のむらの視覚化手法

抄録

We propose a visualization method of uneven areas on single layer thin films formed on optical filters or semiconductor materials. High uniformity of the thickness of thin films is required to produce those devices, in spite of the difficulty of visual inspection. Our method visualizes uneven areas on the film by detecting intensity variances of light interference. To capture images, we utilize a fluorescent lamp with 3 lighting spectrum peaks and a high sensitive color line sensor camera. In the taken color image, uneven areas of thickness of thin films are observed as uneven color areas. Our method displays the uneven color areas based on the average vector of normal area pixels, which are selected by the original techniques to detect non-uniform color areas using color histogram. In our experiments to visualize uneven areas on a thin oxide layer on silicon wafers, we can discern the uneven area of which height has the difference of 2 nanometers from the normal area.