Method of cutting substrate

A substrate cutting method, comprising:

• oscillating ultraviolet laser beams on substrates of a panel along cutting lines to form groove lines in the substrates;
• dividing the panel at the groove lines by applying a force to the panel;
• and
• inverting the panel on a stage prior to the dividing of the panel;
• wherein:
• the groove lines are formed in first surfaces of the substrates, the first surfaces facing the same direction;
• the groove lines overlap each other when viewed in a direction orthogonal to planes of the first surfaces;
• the force is applied to an opposing second surface of one of the substrates;
• the oscillating of the laser beams includes:
• oscillating the laser beams within beam irradiation sections of each of the cutting lines, and
• moving the beam irradiation sections along the respective cutting lines;
• the laser beams have a wavelength of from about 200 nm to about 900 nm;
• the laser beams are pulsed;
• the laser beams form the groove lines by removing portions of the substrates;
• the laser beams have a unit irradiation time of less than about 50 picoseconds;
• the laser beams have a pulse frequency of from about 0.1 MHz to about 100 MHz;
• the dividing of the panel includes disposing a buffer member on an opposing second surface of one of the substrates;
• the oscillating of the laser beams includes using different focal distances for each of the laser beams;
• the panel includes:
• a first glass substrate,
• a second glass substrate disposed to face the first glass substrate, and
• sealants to bond the first glass substrate to the second glass substrate;
• and
• the oscillating of the laser beams includes:
• oscillating a first laser beam on the first glass substrate,
• forming a first groove line in the first glass substrate using the first laser beam,
• oscillating a second laser beam on the second glass substrate, and
• forming a second groove line in the second glass substrate using the second laser beam.