| 摘要 |
PURPOSE:To improve the yield as a product of an IC substrate even if a cassette is deformed or an IC substrate is warped by increasing the angle of a V-shaped groove to a specific angle or larger to reduce the contacting area of the groove of the cassette with the substrate and eliminating a scratch on the peripheral end of the substrate. CONSTITUTION:Reference numeral 13 designates a wafer inserted at the peripheral edge into a pair of opposed V-shaped grooves 12. The angle theta of the grooves 12 is 8 deg. or larger. The groove 12 means substantially V shape in the sectional shapes of two opposed oblique surfaces. The angle theta is that formed of the two oblique surfaces cut by a plane perpendicular to the two opposed oblique surfaces. Since the angle theta of the groove 12 is 8 deg. or larger, the angle between the surface of the wafer 13 contained and the oblique surface of the groove becomes larger than that of the conventional one in a cassette 11. Thus, the contacting area of the peripheral end face of the wafer 13 and the oblique surface is reduced to decrease the depthwise width W of the groove 13, e.g., approx. 1mm.
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