Laser processing apparatus

A laser processing apparatus comprising:

• a chuck table having a holding surface that holds a workpiece and is defined by an X-axis direction and a Y-axis direction;
• and
• a laser beam irradiation unit that irradiates the workpiece held by the chuck table with a laser beam,
• wherein the laser beam irradiation unit includes
• a laser oscillator that emits the laser beam,
• an fθ lens that focuses the laser beam emitted by the laser oscillator on the workpiece held by the chuck table,
• an X-axis optical scanner that is disposed between the laser oscillator and the fθ lens, and induces the laser beam emitted by the laser oscillator in the X-axis direction,
• a Y-axis optical scanner that is disposed between the laser oscillator and the fθ lens, and induces the laser beam emitted by the laser oscillator in the Y-axis direction, and
• a controller,
• wherein the controller includes a spot shape storing section that stores a shape of a spot of the laser beam with which the workpiece held by the chuck table is irradiated, and a processing shape storing section that stores X-coordinates and Y-coordinates on a processing shape to be formed in the workpiece held by the chuck table, and,
• when the workpiece held by the chuck table is irradiated with the laser beam, the controller controls the X-axis optical scanner and the Y-axis optical scanner on a basis of the shape of the spot and the X-coordinates and Y-coordinates on the processing shape, and irradiation with the laser beam is executed in such a manner that a contour of the shape of the spot is positioned to an X-coordinate and Y-coordinate on the processing shape, and that a tangent line to the spot and a tangent line to the processing shape at the X-coordinate and Y-coordinate correspond with each other.