Deposition mask frame assembly, method of fabricating the same, and method of fabricating organic electroluminescent device using the deposition mask frame assembly

1. A method of manufacturing an organic EL device, the method comprising:

forming a first electrode layer in a predetermined pattern on an insulating substrate;

forming an organic film comprising at least a patterned emission layer on the first electrode layer; and

forming a second electrode layer in a predetermined pattern on the organic film;

wherein the organic film and/or the second electrode layer are/is deposited using a deposition mask frame assembly, the deposition mask frame assembly comprising:

a flat mask comprising a flat thin plate in which a predetermined pattern of apertures is formed, the flat mask having a first flat surface extending over an entire area of the flat mask, and a second flat surface extending over the entire area of the flat mask, the second flat surface being separated from the first flat surface by a thickness of the mask;

a flat frame supporting the first flat surface of the flat mask so that the flat mask is tensed and the first flat surface remains flat; and

a flat cover mask supporting the second flat surface of the flat mask so that the second flat surface remains flat; and

wherein the flat mask, the flat frame, and the flat cover mask are held together by welds.

2. The method of claim 1 , wherein the flat mask is formed of nickel or an alloy of nickel and cobalt.

3. The method of claim. 1 , wherein the flat mask is a flat electro-formed mask.

4. The method of claim 1 , wherein the welds are dot welds.

5. The method of claim 4 , wherein a welding pitch between the dot welds is 3 mm or less.

6. The method of claim 1 , wherein the flat mask is tensed with different tensions at different points on each of a plurality of sides of the flat mask.