| 摘要 |
PURPOSE:To prevent the formation of a crown during the implementation of epitaxial growth by making the diameter of a bond wafer shorter than that of a base wafer, selecting a smaller bevel width for the bottom surface of a bond wafer, or adding bevels so that the sizes of the base wafer junction surface and the bond wafer junction surface are the same. CONSTITUTION:An SOI structure substrate is a junction wafer which consists of a base wafer 21a, a bond wafer 21b with a smaller diameter, and an oxide film 21 which joins these wafers and in which the bond wafer 21b is a thin film. Since the bevel width w5 and the bevel angle theta5 of the upper surface of the base wafer 21a disappear in practical terms because the bond wafer 21b is a thin film, values must be set to prevent the formation of a crown during the formation of an epitaxial layer. When the bevel width of a beveled area 32b on the bottom surface of the bond wafer 21b is W8 and the depth of the bevel is d8, W8 is kept to 50mum or less. |
