Laminated wafer processing method

A method of processing a laminated wafer in which a first wafer is laminated on a second wafer, the method comprising:

• a laminated wafer forming step of forming the laminated wafer by laminating the first wafer on the second wafer via an insulating film selected from the group of an oxide film, a nitride film and an oxynitride film;
• a modified layer forming step of forming a modified layer which is not exposed on a surface of the first wafer within the first wafer by positioning a focusing point of a laser beam within the first wafer and moving the first wafer in a horizontal direction relative to the focusing point while applying the laser beam, the modified layer forming step being performed before or after the laminated wafer forming step is performed;
• and
• a separating step of separating only part of the first wafer from the laminated wafer with the modified layer as a boundary, a remaining portion of the first wafer adjacent the insulating film having a predetermined thickness, the separating step being performed after the laminated wafer forming step and the modified layer forming step are performed,
• wherein the laser beam is a multi-spot laser beam.

A method of processing a laminated wafer in which a first wafer is laminated on a second wafer, the method comprising:

• a laminated wafer forming step of forming the laminated wafer by laminating the first wafer on the second wafer via an insulating film selected from the group of an oxide film, a nitride film and an oxynitride film;
• a modified layer forming step of forming a modified layer which is not exposed on a surface of the first wafer within the first wafer by positioning a focusing point of a laser beam within the first wafer and moving the first wafer in a horizontal direction relative to the focusing point while applying the laser beam, the modified layer has a predetermined thickness, the modified layer forming step being performed before or after the laminated wafer forming step is performed;
• and
• a separating step of separating only part of the first wafer from the laminated wafer with the modified layer as a boundary, a remaining portion of the first wafer adjacent the insulating film having a predetermined thickness, the separating step being performed after the laminated wafer forming step and the modified layer forming step are performed;
• a first modified region removing step of removing a modified region remaining on the laminated wafer by polishing to the modified layer of the laminated wafer using a chuck table and a polishing mechanism, the first modified region removing step being performed after the separating step is performed;
• and
• a second modified region removing step of removing a modified region remaining on a separated wafer as the other part of the first wafer by polishing to the modified layer of the separated wafer using another chuck table and another polishing mechanism, the second modified region removing step being performed after the separating step is performed.