Processing method of wafer

A processing method of a wafer having, on a front surface side, a functional layer that forms a plurality of devices disposed in a plurality of regions marked out by a plurality of streets, the processing method comprising:

• a laser processing step of forming laser processed grooves with a depth that exceeds finished thickness of the wafer along the streets while removing the functional layer along the streets by irradiating the front surface side of the wafer with a laser beam having absorbability with respect to the wafer along the streets;
• a protective component sticking step of sticking a protective component to the front surface side of the wafer after execution of the laser processing step;
• a grinding step of causing the laser processed grooves to be exposed on a back surface side of the wafer to divide the wafer into a plurality of device chips by holding the wafer by a chuck table of a grinding apparatus with intermediary of the protective component and grinding the back surface side of the wafer to thin the wafer until thickness of the wafer becomes the finished thickness;
• and
• a processing distortion removal step of supplying a gas in a plasma state to the back surface side of the wafer from the back surface side of the wafer and removing processing distortion formed in the back surface side and side parts of the plurality of device chips,
• wherein a heat affected layer formed around the laser processed grooves is removed in the processing distortion removal step.

A processing method of a wafer having, on a front surface side, a functional layer that forms a plurality of devices disposed in a plurality of regions marked out by a plurality of streets, the processing method comprising:

• a laser processing step of forming laser processed grooves along the streets to divide the wafer into a plurality of device chips while removing the functional layer along the streets by executing irradiation with a laser beam having absorbability with respect to the wafer along the streets;
• a protective component sticking step of sticking a protective component to the front surface side of the wafer after execution of the laser processing step;
• and
• a heat affected layer removal step of supplying a gas in a plasma state to a back surface side of the wafer from the back surface side of the wafer and removing a heat affected layer formed around the laser processed grooves after execution of the protective component sticking step.