A system and method for forming a structure with steep walls (walls having an angle greater than 60 with respect to a level plane) through one or more incremental sheet forming operations is provided. The method includes a workpiece with an inner region and an outer region that are separated by a boundary region. The boundary region includes a plurality of openings and a plurality of connecting elements. The openings are cut into the workpiece using a boundary region cutting tool. A forming tool is configured to operate on the inner region after the boundary region cutting operation has been completed. At least one control unit is in communication with the forming tool. The at least one control unit operates the forming tool to form the structure from the inner region.

Provided is a metal plate to be used for manufacturing a metal mask. In a graph in which an arbitrary position n in a width direction of the metal plate is plotted on a horizontal axis and in which a differential expansion rate En in a unit length L0 in a longitudinal direction is plotted on a vertical axis, a maximum inclination of the differential expansion rate E in a central portion in the width direction is 1.810.sup.3/m or less, and the central portion is a portion that occupies 80% in the width direction excluding both side portions that each occupy 10% in the width direction.

A deposition apparatus includes a chamber, a deposition source disposed in the chamber, a mask assembly, and a base substrate disposed on the mask assembly. The mask assembly includes a frame including frame openings, a mask disposed on the frame and including deposition holes, and a welding stick disposed on the mask. A welding groove is disposed along an edge of the frame and has a depth in the thickness direction of the frame. The welding stick overlaps the welding groove.

A metal mask in which shadow is less likely to occur while the strength is kept, and a method for manufacturing the metal mask are provided. The metal mask includes a first surface, and a second surface positioned opposite to the first surface. The first surface has through-holes, a first top part, and a second top part. The through-holes have a first through-hole, a second through-hole, a third through-hole, a fourth through-hole, a fifth through-hole, and a sixth through-hole. The first through-hole has a first short axis and a first long axis. The second through-hole has a second short axis and a second long axis. The third through-hole has a third short axis and a third long axis. The fourth through-hole has a fourth short axis and a fourth long axis. The fifth through-hole has a fifth short axis and a fifth long axis.

A deposition apparatus includes a chamber, a deposition source disposed in the chamber, a mask assembly, and a base substrate disposed on the mask assembly. The mask assembly includes a frame including frame openings, a mask disposed on the frame and including deposition holes, and a welding stick disposed on the mask. A welding groove is disposed along an edge of the frame and has a depth in the thickness direction of the frame. The welding stick overlaps the welding groove.

A deposition mask comprising; a metal plate including a deposition region and a non-deposition region, wherein the deposition region includes at least one effective portion; wherein the effective portion includes a plurality of unit through-holes, wherein the unit through-holes include a small area hole formed on a first surface of the metal plate; a large area hole formed on a second surface of the metal plate; and a connecting portion connecting the small area hole and the large area hole, wherein a rib is disposed between unit through-holes adjacent in the first direction, wherein an island portion is disposed between the unit through-holes adjacent in the second direction, wherein the island portion includes a first island portion and a second island portion spaced apart from each other, wherein the first island portion contacts the rib, wherein the second island portion is spaced apart from the rib

A deposition mask comprising; a metal plate including a deposition region and a non-deposition region, wherein the deposition region includes at least one effective portion; wherein the effective portion includes a plurality of unit through-holes, wherein the unit through-holes include a small surface hole formed on a first surface of the metal plate; a large surface hole formed on a second surface of the metal plate; and a connecting portion connecting the small surface hole and the large surface hole, wherein the unit through-hole includes a first width defined as a width in a first direction; and a second width defined as a width in a second direction, wherein the first width and the second width are different, wherein a rib is disposed between unit through-holes adjacent in the first direction, wherein an island portion is disposed between the unit through-holes adjacent in the second direction, wherein a height of the small surface hole of the unit through-hole in the second direction is smaller than a height of the small surface hole of the unit through-hole in the first direction.