Deposition mask production method and laser processing apparatus

A production method of a deposition mask including:

• a resin film in which a plurality of penetrating opening patterns is formed;
• and a magnetic metal member disposed in tight contact with one surface of the resin film and in which a plurality of through-holes each having a size capable of enclosing therein at least one of the plurality of penetrating opening patterns is provided, the production method comprising the sequential steps of:
• a first step of forming a mask member having a structure in which the magnetic metal member provided with the plurality of through-holes is in tight contact with the one surface of the resin film;
• a second step of forming a plurality of preliminary opening patterns over an entire surface of the mask member, each of the plurality of preliminary opening patterns having a shape capable of being enclosed in a corresponding one of the plurality of penetrating opening patterns so as to release internal stress of the resin film, by subjecting the resin film to penetration processing by irradiating laser beams at predetermined regular positions in the plurality of through-hole using, among a first slit and a second slit which are included by a laser processing apparatus, the second slit, wherein the first slit has a similar shape to the plurality of penetrating opening patterns and wherein the second slit has a shape capable of being enclosed in each of the plurality of penetrating opening patterns and a similar shape to the plurality of preliminary opening patterns;
• and
• a third step of performing laser processing using the first slit so as to form each of the plurality of penetrating opening patterns at a corresponding one of the predetermined regular positions over the entire surface of the mask member.