Laser dicing device

A laser dicing apparatus making laser light, of which condensing point is arranged to the inside of a wafer, incident through the surface of said wafer while scanning the laser light, and dicing said wafer by forming a modified region inside said wafer to divide said wafer into individual chips, said laser dicing apparatus comprising:

• a first position detecting device detecting a position in the thickness direction of the surface of said wafer at the incident point of said laser light;
• a second position detecting device provided separately from the first position detecting device, and detecting in advance a position in the thickness direction of the surface of said wafer;
• and
• a control section controlling the position in the thickness direction of said condensing position inside said wafer,
• wherein the control section, when scanning said laser light from the outside of a periphery of the wafer to the inside of the periphery of the wafer, performs control based on position data in the thickness direction of the surface of the wafer obtained with said second position detecting device detecting in advance the position in the thickness direction of said condensing point at the periphery of the wafer, and after scanning a predetermined distance, switches to perform control based on position data in the thickness direction of the surface of the wafer obtained by said first position detecting device.