| 摘要 |
PURPOSE:To decrease thermal effects to other impurity diffusion profiles, and to prevent the re-diffusion of diffusion profiles by shaping the forming process of an oxide film for isolating elements so as to cause the irradiation of laser beams to an isolation region. CONSTITUTION:An N<+> buried layer 2 is formed to a P type semiconductor substrate 1, and an N type layer 3 with 1-3mum thickness is grown in an epitaxial shape. An oxidation resisting mask, to which sections 4a-4d corresponding to the electrical isolation region of the I<2>L section and a linear operation transistor section and each I<2>L element isolation region of the I<2>L section are opened, such as a thermal oxide film 5 is formed. A laser is irradiated in the oxidizing atmosphere of oxygen or steam or the like under this condition, the irradiation is continued until oxidation reaches the P<-> substrate 1, and the oxide films 6a-6d are shaped. |
