METHOD OF MANUFACTURING CELL UNIT SUBSTRATE
A method of manufacturing a cell unit substrate, includes: a modified zone-formation step in which modified zones are formed along a predetermined cutting line on the mother substrate to be spaced apart from each other by a first distance by irradiating the mother substrate with laser beams having an energy intensity within an ablation threshold of the mother substrate along the cutting line, a modified zone-etching step in which through-holes are formed along the cutting line on the mother substrate to be spaced apart from each other by the first distance by etching the modified zones, a surface strengthening step in which the mother substrate having the through-holes therein is subjected to surface strengthening, with the mother substrate dipped in a strengthening solution, and a substrate separation step in which the cell unit substrates are separated from the surface-strengthened mother substrate.
1 . A method of manufacturing a plurality of cell unit substrates from a mother substrate, the method comprising:
a modified zone-formation step in which modified zones are formed along a predetermined cutting line on the mother substrate to be spaced apart from each other by a first distance by irradiating the mother substrate with laser beams having an energy intensity within an ablation threshold of the mother substrate along the cutting line;
a modified zone-etching step in which through-holes are formed along the cutting line on the mother substrate to be spaced apart from each other by the first distance by etching the modified zones using an etching solution to remove the modified zones from the mother substrate, with the mother substrate dipped in the etching solution;
a surface strengthening step in which the mother substrate having the through-holes therein is subjected to surface strengthening, with the mother substrate dipped in a strengthening solution, to form a strengthened depth portion to a depth greater than half of the first distance on a surface of each of the through-holes; and
a substrate separation step in which the cell unit substrates are separated from the surface-strengthened mother substrate.
2 . The method according to claim 1 , further comprising:
a substrate treatment step in which the cell unit substrates are treated to provide a functional layer to each of the cell unit substrates on the mother substrate, after the surface strengthening step:
3 . The method according to claim 1 , wherein, in the modified zone-formation step, the modified zones are formed to have a diameter less than the first distance.
4 . The method according to claim 1 , wherein, in the substrate separation step, the cell unit substrates are separated from the mother substrate by physical pressure applied to the cell unit substrate.