| 摘要 |
<p>PURPOSE:To enhance the flatness of wafers by a method wherein a sheet specimen is arranged to come into contact with the ends of multiple projections arrayed in the pitch not exceeding 2mm forming the same surfaces as well as the upper end of an outer peripheral part including the projections so as to make the projections approach to the outer peripheral part. CONSTITUTION:A wafer suction surface comprising an outer peripheral part 2 and a pin part vacuum-sucks at the rear surface of a wafer 1 to be fixed on a wafer suction base 6 by vacuumizing vacuum holes 4 and a bottom part 5. Taking into consideration of the deformation in the wafer when it is vacuum- sucked at, the pitch of projections 3 and the outer peripheral part 2 is specified not to exceed 1mm likewise the pitch between the projections 3 not to exceed 2mm. Furthermore, in oder to improve the effect of avoiding the adhesion of foreign matters, the space of the projections 3 must be narrowed but in order to avoid the damage due to the flattening work load, both the width of outer peripheral part and the diameter of the projections 3 are specified not to exceed 0.5mm. Through these procedures, the deterioration in the flatness due to the existence of the dust, etc., can be avoided.</p> |
