| 摘要 |
PURPOSE:To improve the accuracy of mask positioning to a buried diffusion layer significantly, by a method wherein reflection image of the diffusion layer obtained by projecting infrared ray to the surface of an epitaxial layer is made reference for the mask positioning. CONSTITUTION:An epitaxial layer 4 is formed on a semiconductor substrate 1. In order to detect the position of a buried diffusion layer 2 between the substrate 1 and the epitaxial layer 4, a reflection image 7 of the diffusion layer 2 obtained by projecting infrared ray to the layer 4 is made reference for mask positioning. According to the positioning method, the layer 2 is recognized directly even if there is slackness or misalignment thereby the mask positioning accuracy to the layer 2 can be significantly improved. Therefore isolation failure caused by slackness or misalignment is eliminated and further miniaturization of bipolar IC is possible. |
