Wafer producing method and wafer producing apparatus

Abstract

A method for producing a wafer from a hexagonal single crystal ingot includes: planarizing an upper surface of the hexagonal single crystal ingot; applying a laser beam of such a wavelength as to be transmitted through the ingot, with a focal point positioned in an inside of a region not to be formed with devices of a wafer to be produced from the upper surface of the ingot which has been planarized, to form a production history; and applying a laser beam of such a wavelength as to be transmitted through the hexagonal single crystal ingot with a focal point of the laser beam positioned at a depth corresponding to a thickness of the wafer to be produced from the upper surface of the hexagonal single crystal ingot which has been planarized, to form an exfoliation layer.

What is claimed is: 
     
         1 . A wafer producing apparatus comprising:
 a holding unit adapted to hold a hexagonal single crystal ingot;   a planarizing unit adapted to grind an upper surface of the hexagonal single crystal ingot held by the holding unit to planarize the upper surface;   an exfoliation layer forming unit adapted to apply a laser beam of such a wavelength as to be transmitted through the hexagonal single crystal ingot to the hexagonal single crystal ingot held by the holding unit, with a focal point of the laser beam positioned at a depth corresponding to a thickness of a wafer to the produced from an upper surface of the hexagonal single crystal ingot, to form an exfoliation layer;   a production history forming unit adapted to apply a laser beam of such a wavelength as to be transmitted through the hexagonal single crystal ingot to the hexagonal single crystal ingot, with a focal point of the laser beam positioned in an inside of a region not to be formed with devices of a wafer to be produced, to form a production history;   a wafer exfoliating unit adapted to hold the upper surface of the hexagonal single crystal ingot and exfoliate the wafer from the exfoliation layer; and   a wafer accommodating unit adapted to accommodate the exfoliated wafer.