Mask assembly, deposition apparatus for flat panel displays including the same, and associated methods

Abstract

A mask assembly, a deposition apparatus for flat panel displays including the same, and associated methods, the mask assembly including an open mask having a plurality of first openings, and a pattern mask coupled to the open mask, the pattern mask having a plurality of second openings disposed within an area bounded by the first openings, wherein the open mask is formed of a material having a thermal expansion coefficient that is lower than a thermal expansion coefficient of the pattern mask.

What is claimed is: 
     
         1 . A mask assembly, comprising:
 an open mask having a plurality of first openings; and   a pattern mask coupled to the open mask, the pattern mask having a plurality of second openings disposed within an area bounded by the first openings,   wherein the open mask is formed of a material having a thermal expansion coefficient that is lower than a thermal expansion coefficient of the pattern mask.   
     
     
         2 . The mask assembly as claimed in  claim 1 , wherein the pattern mask is formed by an electroforming method. 
     
     
         3 . The mask assembly as claimed in  claim 1 , wherein the second openings of the pattern mask form a pattern corresponding to a desired pattern of a thin film to be formed on a substrate. 
     
     
         4 . The mask assembly as claimed in  claim 1 , further comprising a frame mask coupled to the open mask, the frame mask having a third opening and the first openings being disposed within an area defined by the third opening. 
     
     
         5 . The mask assembly as claimed in  claim 1 , wherein the open and pattern masks are coupled at first coupling points along edges of the open mask and second coupling points between the first openings of the open mask. 
     
     
         6 . The mask assembly as claimed in  claim 1 , wherein the open mask has a length and a width, the pattern mask has a corresponding length and a corresponding width, and the length and width of the open mask are equal to the corresponding length and width of the pattern mask. 
     
     
         7 . A method of fabricating a mask assembly, comprising:
 preparing an open mask having a plurality of first openings such that each first opening has an area;   preparing a pattern mask having a plurality of second openings such that each second opening has an area relatively smaller than the area of each of the first openings;   aligning the open mask and the pattern mask such that the second openings are disposed within an area bounded by the first openings; and   coupling the open mask to the pattern mask,   wherein the open mask is formed of a material having a thermal expansion coefficient that is lower than a thermal expansion coefficient of the pattern mask.   
     
     
         8 . The method as claimed in  claim 7 , wherein preparing the pattern mask includes performing an electroforming process. 
     
     
         9 . The method as claimed in  claim 7 , wherein preparing the pattern mask includes forming the second openings such that the second openings form a pattern corresponding to a desired pattern of a thin film to be formed on a substrate. 
     
     
         10 . The method as claimed in  claim 7 , wherein the open mask has a length and a width, the pattern mask has a corresponding length and a corresponding width, and the length and width of the open mask are equal to the corresponding length and width of the pattern mask. 
     
     
         11 . The method as claimed in  claim 7 , wherein coupling the open mask to the pattern mask includes:
 a first coupling process, the first coupling process including coupling edges of the open mask to edges of the pattern mask, and   a second coupling process, the second coupling process including binding together the open mask and the pattern mask at regions between the first openings of the open mask.   
     
     
         12 . The method as claimed in  claim 11 , wherein the second coupling process is carried out after the first coupling process is completed. 
     
     
         13 . The method as claimed in  claim 7 , further comprising:
 preparing a frame mask having a third opening;   aligning the frame mask and the open mask such that all the first openings are disposed within an area bounded by the third opening; and   coupling the frame mask to the open mask.   
     
     
         14 . The method as claimed in  claim 13 , wherein coupling the frame mask to the open mask occurs after the open mask is coupled to the pattern mask. 
     
     
         15 . A deposition apparatus for flat panel displays, comprising:
 a process chamber;   an evaporation source disposed on a side of the process chamber;   a mask assembly between the evaporation source and a substrate, the mask assembly including:
 an open mask having a plurality of first openings, and 
 a pattern mask coupled to the open mask, the pattern mask having a plurality of second openings disposed within an area bounded by the first openings; and 
   a holder supporting the substrate and the mask assembly,   wherein the open mask of the mask assembly is formed of a material having a thermal expansion coefficient that is lower than a thermal expansion coefficient of the pattern mask.   
     
     
         16 . The deposition apparatus as claimed in  claim 15 , wherein the pattern mask of the mask assembly is formed by an electroforming method. 
     
     
         17 . The deposition apparatus as claimed in  claim 15 , wherein the second openings of the pattern mask form a pattern corresponding to a desired pattern of a thin film to be formed on the substrate. 
     
     
         18 . The deposition apparatus as claimed in  claim 15 , wherein the mask assembly further includes a frame mask coupled to the open mask, the frame mask having a third opening and the first openings being disposed within an area bounded by the third opening. 
     
     
         19 . The deposition apparatus as claimed in  claim 15 , wherein the open mask is coupled to the pattern mask at first coupling points along edges of the open mask and second coupling points between the first openings of the open mask. 
     
     
         20 . The deposition apparatus as claimed in  claim 15 , wherein the open mask has a length and a width, the pattern mask has a corresponding length and a corresponding width, and the length and width of the open mask are equal to the corresponding length and width of the pattern mask.