Method for processing workpiece

A method for processing a workpiece, the method comprising:

• a setting step of setting a planned processing region;
• a boundary processing step of processing a boundary dividing the planned processing region into a plurality of regions or a boundary dividing the planned processing region and another region from each other;
• a correlation threshold value generating step of generating a correlation threshold value from correlation between energy per pulse and a pulse interval of a first laser beam configured to form a horny layer in the planned processing region;
• an energy and pulse interval setting step of setting the energy per pulse of the first laser beam equal to or higher than the correlation threshold value and setting the pulse interval of the first laser beam equal to or less than the correlation threshold value;
• a horny layer forming step of forming the horny layer by irradiating the planned processing region with the first laser beam, after the setting step, the boundary processing step, and the energy and pulse interval setting step are performed;
• and
• a peeling step of peeling off the horny layer from the workpiece.