Process for forming thin film encapsulation layers

Abstract

A process is disclosed for making a thin film encapsulation package for an OLED device by depositing a thin film material on an OLED device to be encapsulated, comprising simultaneously directing a series of gas flows along substantially parallel elongated output openings, wherein the series of gas flows comprises, in order, at least a first reactive gaseous material, an inert purge gas, and a second reactive gaseous material, optionally repeated a plurality of times, wherein the first reactive gaseous material is capable of reacting with a substrate surface treated with the second reactive gaseous material to form an encapsulating thin film, wherein the first reactive gaseous material is a volatile organo-metal precursor compound. The process is carried out substantially at or above atmospheric pressure, and the temperature of the substrate during deposition is under 250° C.

1 . A process of making a thin film encapsulation package for an OLED device by atomic layer deposition of a thin film material on an OLED device to be encapsulated, comprising simultaneously directing a series of gas flows along substantially parallel elongated output openings, wherein the series of gas flows comprises, in order, at least a first reactive gaseous material, an inert purge gas, and a second reactive gaseous material, optionally repeated a plurality of times, wherein the first reactive gaseous material is capable of reacting with a substrate treated with the second reactive gaseous material to form an encapsulating thin film, wherein the first reactive gaseous material is a volatile organo-metal precursor compound, wherein the process is carried out substantially at or above atmospheric pressure, and wherein the temperature of the substrate during deposition is under 250° C. 
   
   
       2 . The process of  claim 1  wherein the OLED device comprises:
 (a) a first electrode;   (b) a second electrode; and   (c) one or more organic layers formed between the first electrode and the second electrode, at least one organic layer being a light-emitting layer.   
   
   
       3 . The process of  claim 1  wherein the thin film encapsulation package comprises a single layer of a single inorganic compound. 
   
   
       4 . The process of  claim 1  wherein the thin film encapsulation package comprises either (a) at least one first layer of a first inorganic compound and at least one second layer of a second inorganic compound, or (b) a layer that is a mixture of a first inorganic compound and a second inorganic compound. 
   
   
       5 . The process of  claim 4  wherein the first inorganic compound and the second inorganic compound are independently selected from an oxide, nitride, sulfide, and phosphide. 
   
   
       6 . The process of  claim 4  wherein at least one of the first and the second inorganic compound is aluminum oxide. 
   
   
       7 . The process of  claim 4  wherein at least one of the first and the second inorganic compound is an oxide or a nitride. 
   
   
       8 . The process of  claim 4  wherein the first and the second inorganic compound comprises an element that is independently selected from elements in Group 3A, 3B, 4A, and 4B of the Periodic Table. 
   
   
       9 . The process of  claim 4  wherein the first and the second inorganic compound comprises an element that is independently selected from the group consisting of zinc, aluminum, titanium, hafnium, silicon, zirconium, yttrium, and indium. 
   
   
       10 . The process of  claim 1  wherein there is a plurality of first encapsulating thin films and/or plurality of second encapsulating thin films in which the first and the second encapsulating thin films alternate in a stack. 
   
   
       11 . A method of forming an OLED device, comprising:
 (a) providing a substrate with a first electrode and one or more organic layers formed thereon, at least one organic layer being a light-emitting layer;   (b) forming a second electrode comprising a transparent conductive oxide over the one or more organic layers opposite the first electrode; and   (c) forming a thin film encapsulation package as in  claim 1 .   
   
   
       12 . The method of  claim 11 , wherein the thin film encapsulation package is formed at a temperature less than 140 degrees C. 
   
   
       13 . The method of  claim 11  wherein the OLED device is a top-emitting OLED device, wherein the first electrode is a bottom electrode and the second electrode is a top electrode. 
   
   
       14 . The method of  claim 11  wherein the thin film encapsulation package further comprises a layer of parylene polymer. 
   
   
       15 . The process of  claim 1  wherein the series of gas flows are provided by a deposition device comprising, a series of elongated output openings, substantially in parallel, positioned over the substrate in close proximity thereto, in an output face of the deposition device, spaced within 1 mm from a surface of the substrate subjected to deposition. 
   
   
       16 . The process of  claim 15  wherein there are no exhaust channels between the series of elongated output openings for the first reactive gaseous material and the second reactive gaseous material. 
   
   
       17 . The process of  claim 15  wherein the deposition device further comprises exhaust channels between substantially parallel elongated output openings for the first and the second reactive gaseous materials. 
   
   
       18 . The process of  claim 15  wherein the flows of one or more of the gaseous materials to the substrate surface for thin film deposition provides at least part of a force separating the output face of the deposition device from the surface of the substrate. 
   
   
       19 . The process of  claim 1  wherein atomic layer deposition is carried out in a deposition system sequentially comprising:
 (A) an entrance section;   (B) a coating section comprising:
 (i) a plurality of sources for, respectively, a plurality of gaseous materials comprising at least the first reactive gaseous material, the second reactive gaseous material, and the inert purge gas, respectively; 
 (ii) at least one delivery head for delivering the plurality of gaseous materials to the substrate receiving thin film deposition, the delivery head comprising:
 (a) a plurality of inlet ports comprising at least a first, a second, and a third inlet port for receiving the first reactive gas material, the second reactive gaseous material, and the inert purge gas, respectively; and 
 (b) a depositing output face separated a distance from the substrate and comprising a plurality of substantially parallel elongated output openings for each of the first reactive gaseous material, the second reactive gaseous material, and the inert purge gas, wherein the delivery head is designed to deliver the first reactive gaseous material, the second reactive gaseous material, and the inert purge gas simultaneously from the elongated output openings in the depositing output face; 
 
   (C) an exit section;   (D) means for moving the substrate in a unidirectional passage through the coating section; and   (E) means for maintaining a substantially uniform distance between the depositing output face of the delivery head and a surface of the substrate during deposition of the thin film, wherein the delivery head in the coating section is designed to provide flows of one or more of the gaseous materials to the substrate surface for thin film deposition that also provides at least part of a force separating the depositing output face of the delivery head from the surface of the substrate, wherein optionally the entrance section and/or the exit section each comprises a non-depositing output face having a plurality of non-depositing output openings designed to provide gas flow of non-reactive gas to the surface of the substrate during at least part of the passage through the deposition system.   
   
   
       20 . The process of  claim 15  wherein the surface of the substrate is exposed to a gas flow in a channel for less than 100 milliseconds and the relative movement of the substrate to the deposition device is at a speed at least 0.1 cm/sec.