Reducing etch resistance in cutting-edge substrate patterning

Abstract

Embodiments described herein relate to a device comprising a substrate, a pixel defining layer (PDL) structure disposed over the substrate to define subpixels of the device, and a plurality of overhang structures. Each overhang structure is defined by a top structure extending laterally beyond a body structure. Each body structure is disposed over an upper surface of each PDL structure. The overhang structures define a plurality of subpixels including a first subpixel and a second subpixel. Each subpixel includes an anode, an organic light emitting diode (OLED) material, a cathode, and an encapsulation layer. The OLED material is disposed over the first anode and extends below the overhang structure. The cathode is disposed over the OLED material and below the overhang structure. The encapsulation layer is disposed over the first cathode. The first encapsulation layer has a first thickness and the second encapsulation layer has a second thickness different from the first encapsulation layer.

Description

[Background technology]

[0001] Technical Field

[0001] Embodiments described herein relate generally to displays. More specifically, embodiments described herein relate to sub-pixel circuits that may be used in displays, such as organic light emitting diode (OLED) displays, and methods of forming such sub-pixel circuits.

[0002] 2. Description of Related Art

[0002] Input devices, including display devices, can be used in a wide variety of electronic systems. An organic light-emitting diode (OLED) is a light-emitting diode (LED) in which a light-emitting electroluminescent layer is a film of organic compounds that emits light in response to an electric current. OLED devices are classified as bottom-emitting devices if the emitted light passes through a transparent or semi-transparent bottom electrode and a substrate on which the panel is fabricated. Top-emitting devices are classified based on whether the light emitted from the OLED device exits through a lid that is added after the device is fabricated. Today, OLEDs are used in many electronic devices to create display devices. Today's electronic device manufacturers are pushing for the miniaturization of such display devices while achieving higher resolutions than even a few years ago.

[0003]

[0003] Currently, OLED pixel patterning is based on processes that limit panel size, pixel resolution, and substrate size. Photolithography should be used to pattern the pixels, rather than using fine metal masks. Currently, OLED pixel patterning requires the removal of organic materials after the patterning process. Even after being removed, the organic materials leave behind particle problems that impede the performance of the OLED. Therefore, what is needed in the art is a sub-pixel circuit and a method of forming the sub-pixel circuit that can be used in a display, such as an organic OLED display. Summary of the Invention

[0004] In one embodiment, a device is provided. The device includes a substrate, a pixel defining layer (PDL) structure disposed over the substrate to define subpixels of the device, and a plurality of overhang structures. Each overhang structure is defined by an upper extension of a superstructure that extends laterally beyond a body structure. Each body structure is disposed over an upper surface of each PDL structure. The overhang structures define a plurality of subpixels including a first subpixel and a second subpixel. The first subpixel includes a first anode, a first organic light emitting diode (OLED) material, a first cathode, and a first encapsulation layer. The first OLED material is disposed over the first anode, in contact with the first anode, and adjacent the overhang structure. The first cathode is disposed over the first OLED material and adjacent the overhang structure. A first encapsulation layer is disposed over the first cathode and extends under the adjacent overhang structure to contact a portion of the sidewall of the adjacent overhang structure. The first encapsulation layer has a first thickness. The second subpixel includes a second anode, a second OLED material, a second cathode, and a second encapsulation layer. A second organic light emitting diode (OLED) material is disposed over the second anode, in contact with the second anode, and under the overhang structure. The second cathode is disposed over the second OLED material and under the adjacent overhang structure. The second encapsulation layer is disposed over the second cathode and extends under the adjacent overhang structure to contact a portion of the sidewall of the adjacent overhang structure. The second encapsulation layer has a second thickness different from the first thickness.

[0005] In another embodiment, a device is provided. The device includes a substrate, a pixel defining layer (PDL) structure disposed on the substrate to define subpixels of the device, and a plurality of overhang structures. Each overhang structure is defined by an upper extension of a superstructure that extends laterally beyond a body structure to form an overhang. Each body structure is disposed on an upper surface of a respective PDL structure. Adjacent ones of the plurality of overhang structures define a plurality of subpixels including a first subpixel and a second subpixel. The first subpixel includes a first anode, a first organic light emitting diode (OLED) material, a first cathode, and a first encapsulation layer. The first OLED material is disposed on top of and in contact with the first anode, and beneath the adjacent overhang structure. The first cathode is disposed over the first OLED material and beneath the adjacent overhang structure. A first encapsulation layer is disposed over the first cathode and extends under the adjacent overhang structure to contact a portion of the sidewall of the overhang structure. The first encapsulation layer is in the entire area of ​​the overhang and has a first thickness. The second subpixel includes a second anode, a second OLED material, a second cathode, and a second encapsulation layer. The second OLED material is disposed over the second anode, in contact with the second anode, and under the adjacent overhang structure. The second cathode is disposed over the second OLED material and under the adjacent overhang structure. The second encapsulation layer is disposed over the second cathode and extends under the adjacent overhang structure to contact a portion of the sidewall of the adjacent overhang structure. The second encapsulation layer has a second thickness different from the first thickness.

[0006] In yet another embodiment, a device is provided. The device includes a substrate, a pixel defining layer (PDL) structure disposed on the substrate to define subpixels of the device, and a plurality of overhang structures. Each overhang structure is defined by an upper extension of a superstructure that extends laterally beyond a body structure to form an overhang. Each body structure is disposed on an upper surface of a respective PDL structure. Adjacent ones of the plurality of overhang structures define a plurality of subpixels including a first subpixel, a second subpixel, and a third subpixel. The first subpixel includes a first anode, a first organic light emitting diode (OLED) material, a first cathode, and a first encapsulation layer. The first OLED material is disposed over the first anode, in contact with the first anode, and beneath an adjacent overhang structure. The first cathode is disposed over the first OLED material, extends beneath an adjacent overhang structure, and in contact with a portion of the overhang structure. The first encapsulation layer is disposed over the first cathode and extends under the adjacent overhang structure to contact a portion of the sidewall of the overhang structure. The encapsulation layer has a first thickness. The second subpixel includes a second anode, a second OLED material, a second cathode, and a second encapsulation layer. The second OLED material is disposed over the second anode, in contact with the second anode, and under the adjacent overhang structure. The second cathode is disposed over the second OLED material and extends under the adjacent overhang structure to contact a portion of the overhang structure. The second encapsulation layer is disposed over the second cathode and extends under the adjacent overhang structure to contact a portion of the sidewall of the overhang structure. The second encapsulation layer has a second thickness different from the first thickness. The third subpixel includes a third anode, a third OLED material, a third cathode, and a third encapsulation layer. A third OLED material is disposed over and in contact with the third anode and adjacent the overhang structure, and a third cathode is disposed over the third OLED material, extends adjacent the overhang structure, and in contact with a portion of the body structure.A third encapsulation layer is disposed over the third cathode and extends adjacent and beneath the overhang structure to contact a portion of the sidewall of the overhang structure, the encapsulation layer having a third thickness different than the first thickness and the second thickness.

[0007] In yet another embodiment, a device is provided. The device includes a substrate, a pixel defining layer (PDL) structure disposed over the substrate to define subpixels of the device, and a plurality of overhang structures. Each overhang structure is defined by an upper extension of a superstructure that extends laterally beyond a body structure. Each body structure is disposed over an upper surface of a respective PDL structure. Adjacent ones of the plurality of overhang structures define a plurality of subpixels including a first subpixel and a second subpixel. The first subpixel includes a first anode, a first organic light emitting diode (OLED) material, a first cathode, and a first encapsulation layer. The first OLED material is disposed over the first anode, in contact with the first anode, and beneath the adjacent overhang structure. The first cathode is disposed over the first OLED material and beneath the adjacent overhang structure. The first encapsulation layer is disposed over the first cathode and extends under the adjacent overhang structure to contact a portion of the sidewall of the adjacent overhang structure. The first encapsulation layer includes at least two layers of a silicon-containing material. The second subpixel includes a second anode, a second OLED material, a second cathode, and a second encapsulation layer. The second OLED material is disposed over the second anode, in contact with the second anode, and under the adjacent overhang structure. The second cathode is disposed over the second OLED material and under the adjacent overhang structure. The second encapsulation layer is disposed over the second cathode and extends under the adjacent overhang structure to contact a portion of the sidewall of the adjacent overhang structure. The second encapsulation layer includes a silicon-containing material with a different composition than the first encapsulation layer.

[0008]

[0008] So that the above-mentioned features of the present disclosure can be understood in detail, a more detailed description of the present disclosure, briefly summarized above, can be obtained by referring to the embodiments. Some embodiments are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings show only exemplary embodiments, and therefore should not be considered as limiting the scope of the present disclosure, which may also admit of other equally effective embodiments. [Brief description of the drawings]

[0009] [Figure 1A] FIG. 2 is a schematic cross-sectional view of a sub-pixel circuit according to an embodiment. [Figure 1B] FIG. 2 is a schematic cross-sectional view of a sub-pixel circuit according to an embodiment. [Figure 1C] FIG. 2 is a schematic top cross-sectional view of a sub-pixel circuit having a dotted architecture, according to an embodiment. [Figure 1D] FIG. 2 is a schematic cross-sectional view of a sub-pixel circuit having a line-type architecture, according to an embodiment. [Figure 2A] 1 is a schematic cross-sectional view of an overhang structure of a sub-pixel circuit according to an embodiment. [Figure 2B] 1 is a schematic cross-sectional view of an overhang structure of a sub-pixel circuit according to an embodiment. [Diagram 3] FIG. 1 is a flow diagram of an on-demand method for forming sub-pixel circuits, according to an embodiment. [Figure 4A] 1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Figure 4B] 1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Figure 4C] 1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Figure 4D] 1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Figure 4E]1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Figure 4F] 1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Figure 4G] 1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Figure 4H] 1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Figure 4I] 1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Figure 4J] 1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Figure 4K] 1A-1D are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit, according to an embodiment. [Diagram 5] FIG. 2 is a flow diagram of a one-step method for forming a sub-pixel circuit, according to an embodiment. [Figure 6A] 1A-1C are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit according to embodiments described herein. [Figure 6B] 1A-1C are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit according to embodiments described herein. [Figure 6C] 1A-1C are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit according to embodiments described herein. [Figure 6D] 1A-1C are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit according to embodiments described herein. [Figure 6E] 1A-1C are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit according to embodiments described herein. [Figure 6F] 1A-1C are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit according to embodiments described herein. [Figure 6G]1A-1C are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit according to embodiments described herein. [Figure 6H] 1A-1C are schematic cross-sectional views of a substrate in a method for forming a sub-pixel circuit according to embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010]

[0019] To facilitate understanding, the same reference numbers have been used, where possible, to designate identical elements that are common to multiple figures, and it is envisioned that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

[0011]

[0020] FIELD OF THE DISCLOSURE Embodiments described herein relate generally to displays. More specifically, embodiments described herein relate to sub-pixel circuits that may be used in displays, such as organic light emitting diode (OLED) displays, and methods of forming such sub-pixel circuits.

[0012]

[0021] Each of the embodiments of the subpixel circuits described herein includes a plurality of subpixels, each of which is defined by adjacent overhang structures that are permanent in the subpixel circuit. Although the figures depict three subpixels (each of which is defined by adjacent overhang structures), the subpixel circuits of the embodiments described herein include a plurality of subpixels (e.g., three or more subpixels). Each subpixel has an OLED material configured to emit white, red, green, blue, or other color light when energized. For example, the OLED material of a first subpixel emits red light when energized, the OLED material of a second subpixel emits green light when energized, and the OLED material of a third subpixel emits blue light when energized.

[0013]

[0022] The overhang structure is permanent in the subpixel circuit and includes at least a superstructure disposed on the body structure. Adjacent overhang structures that define each subpixel of the subpixel circuit of the display are used to form the subpixel circuit using deposition and to keep the overhang structure in place after the subpixel circuit is formed. Evaporation is used to deposit the OLED materials (including the hole injection layer (HIL), hole transport layer (HTL), emissive layer (EML), and electron transport layer (ETL)) and the cathode. In one embodiment, the HIL layer has a higher conductivity than the HTL layer. In another embodiment, the HIL layer has a higher energy level than the HTL layer. In some cases, the encapsulation layer can be disposed by deposition. In embodiments that include one or more capping layers, the capping layer is disposed between the cathode and the encapsulation layer. The overhang structure and the evaporation angle set by the evaporation source define the deposition angle. That is, the overhang structure is for obtaining a shadowing effect during deposition with the evaporation angle set by the evaporation source. To deposit at a particular angle, the evaporation source is configured to emit deposition material at a particular angle relative to the overhang structures. The encapsulation layer of each of the subpixels is disposed over the cathode such that the encapsulation layer extends under at least a portion of each of the adjacent overhang structures. The encapsulation layer of each subpixel contacts at least a portion of a sidewall of each of the adjacent overhang structures. The encapsulation layer can vary in thickness, composition, and deposition method depending on the OLED material deposited on that subpixel.

[0014]

[0023] FIG 1A is a schematic cross-sectional view of a subpixel circuit 100 having a configuration 101A. The cross-sectional view of FIG 1A is taken along line 1''-1'' in FIG 1C and FIG 1D. FIG 1B is a schematic cross-sectional view of a subpixel circuit 100 having a configuration 101B. The cross-sectional view of FIG 1B is also taken along line 1''-1'' in FIG 1C and FIG 1D.

[0015]

[0024] The subpixel circuit 100 includes a substrate 102. A metal-containing layer 104 may be patterned on the substrate 102. The metal-containing layer 104 is defined by adjacent pixel-defining layer (PDL) structures 126 disposed on the substrate 102. In one embodiment, the metal-containing layer 104 is pre-patterned on the substrate 102. For example, the substrate 102 is a pre-patterned indium tin oxide (ITO) glass substrate. The metal-containing layer 104 is configured to operate the anode of each of the subpixels. The metal-containing layer 104 may include, but is not limited to, chromium, titanium, gold, silver, copper, aluminum, ITO, combinations thereof, or other suitable conductive materials.

[0016]

[0025] The PDL structure 126 is disposed on the surface of the substrate 102. The PDL structure 126 includes one of an organic material, an organic material with an inorganic coating disposed thereon, or an inorganic material. The organic material of the PDL structure 126 includes, but is not limited to, polyimide. The inorganic material of the PDL structure 126 includes, but is not limited to, silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (Si2N2O), magnesium fluoride (MgF2), or combinations thereof. Adjacent PDL structures 126 define each of the subpixels of the subpixel circuit 100 and expose the anode (i.e., the metal-containing layer 104) of each of the subpixels.

[0017]

[0026] The subpixel circuit 100 includes a number of subpixels 106, including at least a first subpixel 108a, a second subpixel 108b, and a third subpixel 108c. Although the figures depict a first subpixel 108a, a second subpixel 108b, and a third subpixel 108c, the subpixel circuit 100 of embodiments described herein may include more than two subpixels 106, such as a fourth and a fifth subpixel. Each subpixel 106 includes an organic light-emitting diode (OLED) material 112 configured to emit white, red, green, blue, or other color light when energized. For example, the OLED material 112 of the first subpixel 108a may emit red light when energized, the OLED material of the second subpixel 108b may emit green light when energized, the OLED material of the third subpixel 108c may emit blue light when energized, and the OLED material of the fourth and fifth subpixels may emit another color light when energized.

[0018]

[0027] The overhang structure 110 is disposed on the surface of the top surface 103 of each of the PDL structures 126. The overhang structure 110 is permanent in the subpixel circuit. The overhang structure 110 further defines each subpixel 106 of the subpixel circuit 100. The overhang structure 110 includes at least a superstructure 110B disposed on the body structure 110A. In one embodiment, the superstructure 110B is disposed on the surface of the body structure 110A. The body structure 110A is disposed on the top surface 103 of the PDL structure 126. In one embodiment, the body structure 110A is disposed on the surface of the top surface 103 of the PDL structure 126. Each overhang structure 110 includes adjacent overhangs 109. The adjacent overhangs 109 are defined by upper extensions 109A of the superstructure 110B that extend laterally beyond the sidewalls 111 of the body structure 110A.

[0019]

[0028] The superstructure 110B includes one of a non-conductive material, an inorganic material, or a metal-containing material. The body structure 110A includes an inorganic material or a metal-containing material. The non-conductive material includes, but is not limited to, an inorganic silicon-containing material. For example, the silicon-containing material includes an oxide or nitride of silicon, or a combination thereof. The metal-containing material includes at least one of a metal or a metal alloy (e.g., titanium (Ti), aluminum (Al), aluminum neodymium (AlNd), molybdenum (Mo), molybdenum tungsten (MoW), copper (Cu), or a combination thereof). The inorganic material of the body structure 110A and the superstructure 110B includes titanium (Ti), silicon nitride (Si3N4), silicon oxide (SiO2), silicon oxynitride (Si2N2O), or a combination thereof. The overhang structure 110 can be held in place (i.e., is permanent). Therefore, after the overhang structures are removed, no organic material remains that could impair the performance of the OLED, and the elimination of the removal process also improves throughput.

[0020]

[0029] In one example, the superstructure 110B includes a non-conductive inorganic material and the body structure 110A includes a conductive inorganic material or a metal-containing material. In another example, the superstructure 110B includes a conductive inorganic material or a metal-containing material and the body structure 110A also includes a conductive inorganic material or a metal-containing material. An auxiliary cathode 202 (see FIG. 2B) may be disposed below the body structure 110A.

[0021]

[0030] The adjacent overhang 109 is defined by an upper extension 109A of the superstructure 110B. At least the bottom surface 107 of the superstructure 110B is wider than the upper surface 105 of the body structure 110A to form the upper extension 109A (see FIG. 1B) of the overhang 109. The superstructure 110B is disposed on the upper surface 105 of the body structure 110A. The upper extension 109A of the superstructure 110B forms the overhang 109 and allows the superstructure 110B to shadow the body structure 110A. The shadowing of the overhang 109 is used for the deposition of each of the OLED material 112 and the cathode 114. The OLED material 112 is disposed below the overhang 109. The cathode 114 is disposed on the OLED material 112 and extends below the overhang 109. In one embodiment, as shown in Figures 2A and 2B, the cathode 114 contacts a first portion 220 of the sidewall 111 of the body structure 110A.

[0022]

[0031] The overhang structure 110 and the evaporation angle set by the evaporation source define the deposition angle. That is, the overhang structure 110 is used to obtain a shadowing effect during deposition with the evaporation angle set by the evaporation source. The overhang 109 and the evaporation source define the OLED angle θ of the OLED material 112. OLED , and the cathode angle θ of the cathode 114 cathode (See FIG. 2A and FIG. 2B). OLED and the cathode angle θ of the cathode 114 cathodeis caused by the evaporation angle set by the overhang structure 110 and the evaporation source. That is, the overhang structure 110 is used to obtain a shadowing effect during the deposition of the OLED material 112 and the cathode 114 with the evaporation angle set by the evaporation source. In one embodiment, the OLED material 112 and the cathode 114 contact the sidewall 111 of the body structure 110A of the overhang structure 110. In another embodiment, the cathode 114 contacts the sidewall 111 of the body structure 110A of the overhang structure 110, as shown in FIG. 1A. In one embodiment, the encapsulation layer 116 is disposed on the sidewall 111 of the body structure 110A and covering the bottom surface 107 of the upper structure 110B, as shown in FIG. 1A. In another embodiment, the body structure 110A is disposed on the auxiliary cathode 202, as shown in FIG. 2B. The auxiliary cathode 202 is disposed on a portion of the top surface 103 of the PDL structure 126. The cathode 114 is in contact with at least the auxiliary cathode 202. In another embodiment, the cathode 114 is in contact with a bus bar (not shown) outside the active area of ​​the subpixel circuit 100. The cathode 114 and the auxiliary cathode 202 include a conductive material, such as a metal or metal alloy. For example, the cathode 114 and / or the auxiliary cathode 202 include, but are not limited to, chromium, titanium, aluminum, ITO, or combinations thereof. In some embodiments, the material of the cathode 114 is different from the material of the body structure 110A and the superstructure 110B.

[0023]

[0032] Each subpixel 106 includes an encapsulation layer 116. For example, the first subpixel 108a has a first encapsulation layer 116A, the second subpixel 108b has a second encapsulation layer 116B, and the third subpixel 108c has a third encapsulation layer 116C. The encapsulation layer 116 may be or may correspond to a local passivation layer. The encapsulation layer 116 of each of the subpixels is disposed over the cathode 114 (and of the OLED material 112) such that it extends under at least a portion of the overhang structure 110 and over at least a portion of each sidewall of an adjacent overhang structure 110. In one embodiment, as shown in subpixels 108b and 108c of FIG. 1A, the second encapsulation layer 116B and the third encapsulation layer 116C are disposed over the cathode 114 and extend under the adjacent overhang 109 to contact a second portion (not shown) of the sidewall 111 of the body structure 110A. In another embodiment, as shown in subpixel 108a of FIG. 1A, the first encapsulation layer 116A is disposed over the sidewall 111 of the body structure 110A and over the bottom surface 107 of the superstructure 110B. In another embodiment, as shown in subpixel 108a of FIG. 1B, the first encapsulation layer 116A is disposed over the sidewall 111 of the body structure 110A, the bottom surface 107 of the superstructure 110B, the sidewall 113 of the superstructure 110B, and a portion of the top surface 115 of the superstructure 110B of the overhang structure 110. The encapsulation layer 116 further includes a top surface 119 that defines a top edge of the encapsulation layer 116 between the sidewalls 111 of the body structure 110A.

[0024]

[0033] In embodiments including one or more capping layers, the capping layer is disposed between the cathode 114 and the encapsulation layer 116. For example, a first capping layer and a second capping layer are disposed between the cathode 114 and the encapsulation layer 116. Each of the embodiments described herein may include one or more capping layers disposed between the cathode 114 and the encapsulation layer 116. The first capping layer may include an organic material. The second capping layer may include an inorganic material (such as lithium fluoride). The first capping layer and the second capping layer may be deposited by evaporation. In another embodiment, the subpixel circuit 100 further includes a global passivation layer 120 disposed over at least the overhang structure 110 and the encapsulation layer 116. In yet another embodiment, the subpixel includes an intermediate passivation layer disposed over the overhang structure 110 of each subpixel 106 and between the encapsulation layer 116 and the global passivation layer 120.

[0025]

[0034] Configuration 101A and configuration 101B of subpixel circuit 100 further include at least a global passivation layer 120 disposed on overhang structure 110 and encapsulation layer 116. In one embodiment, an intermediate layer 118 may be disposed between global passivation layer 120 and overhang structure 110 and encapsulation layer 116. Intermediate layer 118 may include an inkjet material, such as an acrylic material.

[0026]

[0035] FIG. 1C is a schematic top cross-sectional view of a subpixel circuit 100 having a dot-type architecture 101C. FIG. 1D is a schematic cross-sectional view of a subpixel circuit 100 having a line-type architecture 101D. Each of the top cross-sectional views of FIG. 1C and FIG. 1D is taken along line 1'-1' of FIG. 1A and FIG. 1B. The dot-type architecture 101C includes a plurality of pixel openings 124A with adjacent PDL structures 126. Each of the pixel openings 124A is surrounded by an overhang structure 110 (see FIG. 1A) that defines each of the subpixels 106 of the dot-type architecture 101C. The line-type architecture 101D includes a plurality of pixel openings 124B with adjacent PDL structures 126. Each of the pixel openings 124B is abutted by an overhang structure 110 (see FIG. 1A) that defines each of the subpixels 106 of the line-type architecture 101D.

[0027]

[0036] FIG. 2A is a schematic cross-sectional view of the overhang structure 110 of the subpixel circuit 100. FIG. 2B is also a schematic cross-sectional view of the overhang structure 110 of the subpixel circuit 100. In one embodiment, the overhang structure 110 includes a superstructure 110B of a non-conductive inorganic material and a body structure 110A of a conductive inorganic material. In another embodiment, the overhang structure 110 includes a superstructure 110B of a conductive inorganic material and a body structure 110A of a conductive inorganic material. In one embodiment, the cathode 114 contacts the body structure 110A of the overhang structure 110. In another embodiment, the body structure 110A is disposed above the auxiliary cathode 202, as shown in FIG. 2B. The cathode 114 contacts at least the auxiliary cathode 202. In another embodiment, the cathode 114 contacts a bus bar (not shown) outside the active area of ​​the subpixel circuit 100.

[0028]

[0037] The top structure 110B includes a lower edge 206 and an overhang vector 208. The lower edge 206 extends beyond the sidewall 111 of the body structure 110A. The overhang vector 208 is defined by the lower edge 206 and the PDL structure 126. The OLED material 112 is disposed over the metal-containing layer 104, over the sidewall 127 of the PDL structure 126, and over a first portion 210 of the top surface 103 of the PDL structure 126, and extends below the overhang 109 to an OLED endpoint 218. The OLED material 112 has an OLED angle θ between the OLED vector 212 and the overhang vector 208. OLED The OLED vector 212 is defined by an OLED end point 218 that extends below the superstructure 110B and a lower edge 206 of the superstructure 110B. In one embodiment, the OLED material 112 can include one or more of an HIL, an HTL, an EML, and an ETL.

[0029]

[0038] The cathode 114 is disposed over the OLED material 112, over a first portion 210 of the PDL structure 126, and over a second portion 211 of the top surface 103 of the PDL structure 126 in each subpixel 106. In some embodiments that may be combined with other embodiments described herein, the cathode 114 is disposed on the first portion 220 of the sidewall 111 of the body structure 110A. In another embodiment that may be combined with other embodiments described herein, as shown in FIG. 2B, the cathode 114 contacts a portion 222 of the auxiliary cathode 202. In an embodiment in which the cathode 114 contacts a portion 222 of the auxiliary cathode 202, the cathode 114 also contacts the first portion 220 of the sidewall 111 of the body structure 110A. The cathode 114 is disposed at a cathode angle θ between the cathode vector 224 and the overhang vector 208. cathode A cathode vector 224 is defined by a cathode endpoint 226 that extends below the upper structure 110B and the lower edge 206 of the upper structure 110B.

[0030]

[0039] The encapsulation layer 116 is disposed over the cathode 114 (and the OLED material 112) so as to extend at least under the superstructure 110B of the overhang structure 110 and over at least a portion of the sidewalls of the overhang structure 110. In one embodiment, as shown in subpixels 108b and 108c in Figures 1A and 1B, a second encapsulation layer 116B and a third encapsulation layer 116C are disposed over the cathode 114 and extend under adjacent overhangs 109 to contact a second portion (not shown) of the sidewall 111 of the body structure 110A. In another embodiment, as shown in Figure 2A, the first encapsulation layer 116A is disposed over the sidewall 111 of the body structure 110A and over the bottom surface 107 of the superstructure 110B. 2B, the first encapsulation layer 116A contacts the sidewalls 111 of the body structure 110A, the bottom surface 107 of the superstructure 110B, the sidewalls 113 of the superstructure 110B, and a portion of the top surface 115 of the superstructure 110B of the overhang structure 110. The encapsulation layer 116 further includes a top surface 119 between the sidewalls 111 of the body structure 110A that defines a top edge of the encapsulation layer 116.

[0031]

[0040] The encapsulation layers 116 may be modified using deposition thicknesses. Each encapsulation layer 116 has a thickness. The thickness is the distance from the bottom surface of the encapsulation layer to the top surface of the encapsulation layer 116. The first encapsulation layer 116A has a first thickness t1, the second encapsulation layer 116B has a second thickness t2, and the third encapsulation layer 116C has a third thickness t3. In another embodiment, the second thickness t2 is different from the first thickness t1 and the third thickness t3, and the third thickness t3 is different from the first thickness t1 and the second thickness t2. In one embodiment, as shown in FIG. 1A, the thickness t1 is thicker than the thickness t2 and the thickness t3, and the thickness t2 is thicker than the thickness t3. In another embodiment, as shown in FIG. 1B, the thickness t1 is thinner than the thickness t2 and the thickness t3, and the thickness t2 is thinner than the thickness t3. In another embodiment, the thickness t2 is thicker than the thickness t1 and the thickness t3, and the thickness t1 is thicker than the thickness t3. In another embodiment, thickness t2 is greater than thickness t1 and thickness t3, and thickness t3 is greater than thickness t1.

[0032]

[0041] In another embodiment, the thickness of the encapsulation layer 116 increases as the wavelength of the emitted light increases. For example, the first encapsulation layer 116A has the thickest thickness t1 (~580 nm) in the subpixel 108a having the red OLED material 112, the second encapsulation layer 116B has the thinnest thickness t2 (~540 nm) in the second subpixel 108b having the green OLED material 112, and the third encapsulation layer 116C has the thinnest thickness t3 (~440 nm) in the subpixel 108c having the blue OLED material 112. In another embodiment, the thickness of the encapsulation layer 116 decreases as the wavelength of the emitted light increases. For example, the first encapsulation layer 116A in the subpixel 108a having the red OLED material 112 has the thinnest thickness t1 (~580 nm), the second encapsulation layer 116B in the second subpixel 108b having the green OLED material 112 has the thickest thickness t2 (~540 nm), and the third encapsulation layer 116C in the subpixel 108c having the blue OLED material 112 has the thickest thickness t3 (~440 nm). In another embodiment, the thickness of the encapsulation layer 116 may vary regardless of the type of OLED light used in the subpixels 108a, 108b, and 108c. The thickness of the encapsulation layer in each subpixel is varied to protect the previously deposited layers during the etching of the subsequent encapsulation layers. The thicknesses t1, t2, and t3 may range between about 0.5 μm and about 2.0 μm (e.g., between about 0.8 μm and about 1.2 μm).

[0033]

[0042] The encapsulation layer 116 includes a non-conductive inorganic material, such as a silicon-containing material. The silicon-containing material may include a silicon nitride (e.g., Si3N4) material, a silicon oxynitride material (e.g., Si2N2O), a silicon oxide material (e.g., SiO2), or a combination thereof. In one embodiment, the first encapsulation layer 116A includes a silicon nitride material, the second encapsulation layer 116B includes a silicon oxynitride material, and the third encapsulation layer 116C includes a silicon oxide. The thickness of the encapsulation layer 116 may depend on the etch selectivity of the material of the encapsulation layer 116. The silicon-containing material may be further modified to change the optical properties of the encapsulation layer 116. For example, the silicon-containing material may be tuned to increase or decrease the refractive index. The difference in refractive index may also affect the etch rate of the encapsulation layer 116. This allows for additional etch selectivity control of the encapsulation layer 116. In one embodiment, the first encapsulation layer 116A has a first refractive index, the second encapsulation layer 116B has a second refractive index, and the third encapsulation layer 116C has a third refractive index. In this embodiment, the first, second, and third refractive indices are different from one another.

[0034]

[0043] At least one of the first encapsulation layer 116A, the second encapsulation layer 116B, and the third encapsulation layer 116C may include at least two layers of silicon-containing material. At least one of the first encapsulation layer 116A, the second encapsulation layer 116B, and the third encapsulation layer 116C includes a composition in at least one of the layers of silicon-containing material that is different from the composition of the other encapsulation layers 116. In a first example, the first encapsulation layer I116A includes a silicon oxynitride material on a silicon nitride material. The second encapsulation layer 116B includes a silicon oxide layer on a silicon nitride layer. The third encapsulation layer 116C includes a silicon nitride layer on a silicon oxide layer. In a second example, the first encapsulation layer I116A includes a silicon oxide layer on a silicon oxynitride layer. The second encapsulation layer 116B includes a silicon nitride layer on a silicon oxynitride layer. The third encapsulation layer 116C includes a silicon oxynitride layer over a silicon oxide layer. The silicon nitride material has a thickness of about 0.8 μm to about 1.2 μm. The silicon oxynitride layer has a thickness of about 0.2 μm to about 0.4 μm. The silicon oxide layer has a thickness of about 0.2 μm to about 0.4 μm.

[0035]

[0044] The encapsulation layer 116 may be further modified using various modes of deposition, such as atomic layer deposition (ALD), chemical vapor deposition (CVD), and physical vapor deposition (PVD). In one example, the first subpixel 108a includes silicon nitride deposited using CVD and silicon oxide deposited using ALD. The second subpixel 108b includes silicon nitride deposited using CVD and silicon oxynitride deposited using CVD. The third subpixel 108c includes silicon nitride deposited using CVD. The encapsulation layer 116 may be further modified between using inductively coupled plasma (IDP) or conductively coupled plasma (CCP) for the deposition process.

[0036]

[0045] Varying the composition, deposition method, and thickness of the encapsulation layer 116 for each subpixel protects the previously deposited layers during the deposition of subsequent layers, improving process yield and efficiency. Varying the thickness of the encapsulation layer 116 further controls the distance between the lower edge 206 and the top surface of the encapsulation layer 116 (see subpixels 108b and 108c in FIGS. 1A and 1B), as well as the distance between the encapsulation edge 230 of the encapsulation layer 116 and the top surface 119 of the encapsulation layer 116. Such distance controls the amount of etching and deposition that occurs under the overhang structure 110, providing increased protection of the OLED material 112 during subsequent depositions and etches.

[0037]

[0046] The encapsulation layer 116 extends under the overhang structure 110 to contact the second portion of the body structure 110A. A distance is defined between the encapsulation edge 230 and the top surface 119 of the encapsulation layer 116. In one embodiment, the first encapsulation layer 116A is in the entire area of ​​the overhang 109. In this embodiment, the encapsulation layer has a thickness t1 from the bottom surface 107 of the upper structure 110B to the bottom surface of the first encapsulation layer 116A. For example, there is no distance between the encapsulation edge 230 and the top surface 119 of the encapsulation layer 116. In another embodiment, as illustrated in subpixel 108a of Figures 1B and 2B, the first encapsulation layer 116A extends under the overhang structure 110 to contact the body structure 110A, the bottom surface 107 of the superstructure 110B, the sidewalls 113 of the superstructure 110B, and a portion 117 of the top surface 115 of the superstructure 110B. The first encapsulation layer 116A has a thickness t1 that fills a portion of the area under the overhang 109. A gap is defined between the first encapsulation layer 116A on the surface of the bottom surface 107 of the superstructure 110B and the first encapsulation layer 116A above the cathode 114. The thickness t1 determines the distance D1 of the gap between the encapsulation edge 230 of the first encapsulation layer 116A and the top surface 119. In another embodiment, as illustrated in the second subpixel 108b of FIG. 1A and FIG. 1B, the second encapsulation layer 116B extends under the overhang structure 110 and contacts a portion of the body structure 110A. The second encapsulation layer 116B has a second thickness t2 that fills a portion of the area under the overhang 109 in the second subpixel. A gap is defined between the lower edge 206 of the upper structure 110B and the second encapsulation layer 116B above the cathode 114. The second thickness t2 determines the distance D2 of the gap between the lower edge 206 and the upper surface 119 of the second encapsulation layer 116B. In another embodiment, as illustrated in the subpixel 108c of FIG. 1A and FIG. 1B, the third encapsulation layer 116C extends under the overhang structure 110 and contacts a portion of the body structure 110A. The third encapsulation layer 116C has a third thickness t3 that fills a portion of the area under the overhang 109 in the third subpixel 108c. A gap is defined between the lower edge 206 of the superstructure 110B and the third encapsulation layer 116C over the cathode 114.The third thickness t3 determines a gap distance D3 between the lower edge 206 and the top surface 119 of the third encapsulation layer 116C. In yet another embodiment, the first encapsulation layer 116A has a first thickness t1, the second encapsulation layer 116B has a second thickness t2, and the third encapsulation layer 116C has a third thickness t3. The second thickness t2 is different from the first thickness t1. The third thickness t3 is different from the first thickness t1 and the second thickness t2. FIG. 1A illustrates an embodiment in which the first encapsulation layer 116A of the first subpixel 108a is within the entire area of ​​the overhang, while FIG. 1B illustrates an embodiment in which the first encapsulation layer 116A of the first subpixel 108a encompasses a portion of the top surface 115 of the superstructure 110B, and the first encapsulation layer 116A of the first subpixel 108a, the second encapsulation layer 116B of the second subpixel 108b, and the third encapsulation layer 116c of the third subpixel 108c may include any combination of the embodiments described herein.

[0038]

[0047] During deposition of the OLED material 112, the lower edge 206 of the superstructure 110B defines the location of the OLED endpoint 218. For example, the OLED material 112 is evaporated at an OLED maximum angle corresponding to the OLED vector 212, and the lower edge 206 ensures that the OLED material 112 is not deposited beyond the OLED endpoint 218. During deposition of the cathode 114, the lower edge 206 of the superstructure 110B defines the location of the cathode endpoint 226. For example, the cathode 114 is evaporated at a cathode maximum angle corresponding to the cathode vector 224, and the lower edge 206 ensures that the cathode 114 is not deposited beyond the cathode endpoint 226. OLED angle θ OLED is the cathode angle θ cathode falls below.

[0039]

[0048] 3 is a flow diagram of a method 300 for forming a subpixel circuit 100, according to an embodiment. Figures 4A-4K are schematic cross-sectional views of a substrate 102 during a method 300 for forming a subpixel circuit 100, according to an embodiment described herein. The method 300 described herein provides the ability to fabricate both subpixel circuits 100 having a dot-type architecture 101C and subpixel circuits 100 having a line-type architecture 101D.

[0040]

[0049] In step 301, as shown in FIG. 4A, a body structure layer 402A and a super structure layer 402B are deposited on the substrate 102. The body structure layer 402A is disposed on the PDL structure 126 and the metal-containing layer 104. The super structure layer 402B is disposed on the body structure layer 402A. The body structure layer 402A corresponds to the body structure 110A and the super structure layer 402B corresponds to the super structure 110B of the overhang structure 110. In some embodiments of the overhang structure 110, an auxiliary cathode layer (not shown) is disposed between the body structure layer 402A and the PDL structure 126 and the metal-containing layer 104.

[0041]

[0050] In step 302, a resist 406 is deposited and patterned, as shown in FIG. 4B. The resist 406 is deposited on the upper structural layer 402B. The resist 406 can be a positive resist or a negative resist. A positive resist includes portions of the resist that become soluble in a resist developer when exposed to electromagnetic radiation. The resist developer is applied to the resist after a pattern has been written into the resist using electromagnetic radiation. A negative resist includes portions of the resist that become insoluble in a resist developer when exposed to electromagnetic radiation. The resist developer is applied to the resist after a pattern has been written into the resist using electromagnetic radiation. The chemical composition of the resist determines whether the resist 406 is a positive photoresist or a negative photoresist. The resist 406 is patterned to form one of the pixel openings 124A of the dot-type architecture 101C or the pixel opening 124B of the line-type architecture 101D of the first sub-pixel 108a. The patterning is one of a photolithography, a digital lithography process, or a laser ablation process.

[0042]

[0051] In step 303, as shown in FIG. 4C, the upper structural layer 402B and the body structural layer 402A are removed in portions exposed by the pixel openings 124A, 124B. The upper structural layer 402B exposed by the pixel openings 124A, 124B may be removed by a dry etching process or a wet etching process. The body structural layer 402A exposed by the pixel openings 124A, 124B may be removed by a dry etching process or a wet etching process. In an embodiment including an auxiliary cathode layer, a portion of the auxiliary cathode layer may be removed by a dry etching process or a wet etching process to form an auxiliary cathode 202 disposed under the body structure 110A. In step 303, the overhang structure 110 of the first subpixel 108a is formed. The etching selectivity between the material of the upper structure layer 402B corresponding to the upper structure 110B and the material of the body structure layer 402A corresponding to the body structure 110A, and the etching process for removing the exposed portions of the upper structure layer 402B and the body structure layer 402A are used to make the bottom surface 107 of the upper structure 110B wider than the top surface 105 of the body structure 110A (as shown in Figures 1A, 1B, 2A, and 2B) and form an upper extension 109A that defines an overhang 109. The shadowing of the overhang 109 is used for the deposition of the OLED material 112 and the cathode 114.

[0043]

[0052] In step 304, the OLED material 112, the cathode 114, and the encapsulation layer 116 of the first subpixel 108a are deposited, as shown in FIG. 4D. Shadowing of the overhang 109 is used for each deposition of the OLED material 112 and the cathode 114. As detailed in the description corresponding to FIG. 2, the shadowing effect of the overhang structure 110 causes the OLED angle θ of the OLED material 112 to change. OLED (see FIGS. 1A and 2A), and the cathode angle θ of the cathode 114 cathode (See FIG. 1A and FIG. 2A) is defined. OLED and the cathode angle θ of the cathode 114 cathode1 is by evaporation of the OLED material 112 and the cathode 114. In one embodiment, the cathode 114 contacts the body structure 110A of the overhang structure 110. In another embodiment, the cathode 114 contacts at least the auxiliary cathode 202. The encapsulation layer 116 is deposited with a thickness t1 on the cathode 114. In embodiments including a capping layer, the capping layer is deposited between the cathode 114 and the encapsulation layer 116. The capping layer may be deposited by evaporation.

[0044]

[0053] In step 305, a resist 408 is formed in the well 410 of the first subpixel 108a, as shown in FIG. 4E. In one embodiment, the thickness of the resist 408 is different from the thickness of the resist 406. In step 306, the encapsulation layer 116, the cathode 114, and the OLED material 112 exposed by the resist 408 are removed, as shown in FIG. 4F. The encapsulation layer 116, the cathode 114, and the OLED material 112 exposed by the resist 408 may be removed by a wet etching process. The resist 408 is removed from the well, leaving behind the overhang structure 110. In step 307, a resist 412 is deposited and patterned, as shown in FIG. 4G. In one embodiment, the thickness of the resist 412 is different from the thicknesses of the resist 406 and the resist 408. A resist 412 is disposed on the upper structure layer 402B and the upper structure 110B of the first subpixel 108a. The resist 412 is patterned to form either the pixel opening 124A of the dot-type architecture 101C or the pixel opening 124B of the line-type architecture 101D of the second subpixel 108b.

[0045]

[0054] In step 308, as shown in FIG. 4H, the upper structural layer 402B and the body structural layer 402A are removed in portions exposed by the pixel openings 124A, 124B of the second subpixel 108b. The upper structural layer 402B exposed by the pixel openings 124A, 124B may be removed by a dry etching process or a wet etching process. The body structural layer 402A exposed by the pixel openings 124A, 124B may be removed by a dry etching process or a wet etching process. In an embodiment including an auxiliary cathode layer, a portion of the auxiliary cathode layer may be removed by a dry etching process or a wet etching process to form an auxiliary cathode 202 disposed under the body structure 110A. In step 308, the overhang structure 110 of the second subpixel 108b is formed. The etch selectivity of the material of the superstructure layer 402B corresponding to the superstructure 110B and the material of the body structure layer 402A corresponding to the body structure 110A, and the etching process for removing the exposed portions of the superstructure layer 402B and the body structure layer 402A are used to make the bottom surface 107 of the superstructure 110B wider than the top surface 105 of the body structure 110A (as shown in FIG. 1A ) to form an upper extension 109A that defines an overhang 109. The shadowing of the overhang 109 is used for the deposition of the OLED material 112 and the cathode 114.

[0046]

[0055] In step 309, the OLED material 112, cathode 114, and encapsulation layer 116 of the second subpixel 108b are deposited, as shown in FIG. 4I. In embodiments including a capping layer, the capping layer is deposited between the cathode 114 and the encapsulation layer 116. The capping layer may be deposited by evaporation. Shadowing of the overhang 109 is used for the evaporation of the OLED material 112 and the cathode 114. The shadowing effect of the overhang structure 110 reduces the OLED angle θ of the OLED material 112. OLED and the cathode angle θ of the cathode 114 cathode The OLED angle θ of the OLED material 112 is defined. OLED and the cathode angle θ of the cathode 114cathode is produced by deposition of OLED material 112 and cathode 114. In one embodiment, cathode 114 contacts body structure 110A of overhang structure 110. In another embodiment, cathode 114 contacts at least auxiliary cathode 202. Encapsulation layer 116 is deposited with thickness t2 over cathode 114. In one embodiment, thickness t2 is less than thickness t1. In another embodiment, thickness t2 is greater than thickness t1.

[0047]

[0056] In step 310, resist 416 is formed in the well of the second subpixel 108b, as shown in FIG. 4J. In one embodiment, the thickness of resist 416 is different from the thicknesses of resist 406, resist 408, and resist 412. In step 311, the encapsulation layer 116, cathode 114, and OLED material 112 exposed by resist 416 are removed, as shown in FIG. 4K. The encapsulation layer 116, cathode 114, and OLED material 112 exposed by resist 416 can be removed by a wet etching process. Resist 416 is removed from the well, leaving behind an overhang structure 110. Steps 301-311 described herein form a subpixel circuit 100 including two subpixels 106. Steps 306-310 can be repeated for each of the additional subpixels (e.g., a third and / or fourth subpixel). The encapsulation layer 116 of the third subpixel 108c shown in FIG. 1A and FIG. 1B has a thickness t3. The additional pixel 108n, if any, has a thickness t nIn one embodiment, the thickness t3 of the encapsulation layer 116 in the subpixel 108c is less than the thicknesses t1 and t2. In another embodiment, the thickness t3 of the encapsulation layer 116 in the subpixel 108c is greater than the thicknesses t1 and t2. In another embodiment, the thickness t3 of the encapsulation layer 116 in the subpixel 108c is less than the thickness t1 and greater than the thickness t2. In another embodiment, the thickness t3 of the encapsulation layer 116 in the subpixel 108c is greater than the thickness t1 and less than the thickness t2. In another embodiment, the thickness of the encapsulation layer 116 increases as the wavelength of the emitted light increases. In another embodiment, the thickness of the encapsulation layer 116 decreases as the wavelength of the emitted light increases.

[0048]

[0057] The thickness, composition, and deposition method of the encapsulation layer 116 can be varied as described above. Varying the composition and deposition method of the encapsulation layer 116 to produce a variation in thickness protects the deposited OLED material 112 from damage during layer deposition, improving process yield and efficiency. Varying the thickness of the encapsulation layer 116 further controls the distance between the lower edge 206 and the top surface of the encapsulation layer 116 (see subpixels 108b and 108c in Figures 1 and 2), and the distance between the encapsulation edge 230 of the encapsulation layer 116 and the top surface 119 of the encapsulation layer 116. Such distance controls the amount of etching and deposition that occurs under the overhang structure 110, providing increased protection of the OLED material 112 in subsequent depositions and etches.

[0049]

[0058] Figure 5 is a flow diagram of a method 500 for forming the sub-pixel circuit 100. Figures 6A-6H are schematic cross-sectional views of a substrate 102 in a method 500 for forming the sub-pixel circuit 100 according to embodiments described herein.

[0050]

[0059] In step 501, a body structure layer 402A and a super structure layer 402B are deposited on the substrate 102, as shown in FIG. 6A. The body structure layer 402A is disposed on the PDL structure 126 and the metal-containing layer 104. The super structure layer 402B is disposed on the body structure layer 402A. The body structure layer 402A corresponds to the body structure 110A, and the super structure layer 402B corresponds to the super structure 110B of the overhang structure 110. In some embodiments of the overhang structure 110, an auxiliary cathode layer 404 is disposed between the body structure layer 402A and the PDL structure 126 and the metal-containing layer 104. The auxiliary cathode layer 404 corresponds to the auxiliary cathode 202. A resist 406 is disposed and patterned on the super structure layer 402B to expose the pixel openings 124A, 124B. In step 502, as shown in FIG. 6B, the overhang structure portions of the upper structural layer 402B and the body structural layer 402A exposed by the pixel openings 124A, 124B are removed. The upper structural layer 402B exposed by the pixel openings 124A, 124B can be removed by a dry etching process or a wet etching process. The body structural layer 402A exposed by the pixel openings 124A, 124B can be removed by a dry etching process or a wet etching process.

[0051]

[0060] In step 503, the OLED material 112, cathode 114, and encapsulation layer 116 of the first subpixel 108a are deposited, as shown in FIG. 6C. In embodiments including a capping layer, the capping layer is deposited between the cathode 114 and the encapsulation layer 116. The capping layer may be deposited by evaporation. As detailed in the description corresponding to FIG. 2B, the OLED angle θ of the OLED material 112 is increased by the shadowing effect of the overhang structure 110. OLED (see FIG. 2B), as well as the cathode angle θ cathode (See FIG. 2B) is defined. OLED and the cathode angle θ of the cathode 114 cathodeis due to deposition of OLED material 112 and cathode 114. In one embodiment, cathode 114 contacts body structure 110A of overhang structure 110. In another embodiment, cathode 114 contacts at least auxiliary cathode 202. An encapsulation layer 116 is deposited over cathode 114 with a thickness t1.

[0052]

[0061] In step 504, as shown in Figure 6D, a resist 602 is formed in the well of the first subpixel 108a. In one embodiment, the resist 602 has a thickness different from the thickness of the resist 406. In step 505, as shown in Figure 6E, the encapsulation layer 116, the cathode 114, and the OLED material 112 exposed by the resist 602 are removed. The encapsulation layer 116, the cathode 114, and the OLED material 112 exposed by the resist 602 can be removed by a wet etching process. The resist 602 is removed.

[0053]

[0062] In step 506, the OLED material 112, cathode 114, and encapsulation layer 116 of the second subpixel 108b are deposited, as shown in FIG. 6F. A resist 604 is formed in the well of the first subpixel 108a, and the OLED material 112, cathode 114, and encapsulation layer 116 are deposited on top of the resist 604. In one embodiment, the resist 604 has a thickness different from that of the resist 602 and the resist 406. In an embodiment including a capping layer, the capping layer is deposited between the cathode 114 and the encapsulation layer 116. The capping layer may be deposited by evaporation. Shadowing of the overhang 109 is used for the deposition of each of the OLED material 112 and the cathode 114. The shadowing effect of the overhang structure 110 reduces the OLED angle θ of the OLED material 112. OLED and the cathode angle θ of the cathode 114 cathode The OLED angle θ of the OLED material 112 is defined. OLED and the cathode angle θ of the cathode 114 cathodeis due to deposition of OLED material 112 and cathode 114. In one embodiment, cathode 114 contacts body structure 110A of overhang structure 110. Cathode 114 contacts at least auxiliary cathode 202. Encapsulation layer 116 is deposited with thickness t2 over cathode 114. In one embodiment, thickness t2 is less than thickness t1. In another embodiment, thickness t2 is greater than thickness t1.

[0054]

[0063] In step 507, resist 606 is formed in the well of second subpixel 108b, as shown in Figure 6G. In one embodiment, resist 606 has a thickness different than the thicknesses of resist 406, resist 602, and resist 604. In step 508, the encapsulation layer 116, cathode 114, and OLED material 112 exposed by resist 416 are removed, as shown in Figure 6H. The encapsulation layer 116, cathode 114, and OLED material 112 exposed by resist 606 can be removed by a wet etching process. Resist 606 is removed.

[0055]

[0064] Steps 501-508 described herein form a subpixel circuit 100 that includes two or more subpixels 106. Steps 505-508 may be repeated for each additional subpixel (e.g., a third and / or fourth subpixel). For the third subpixel 108c shown in Figures 1A and 1B, the encapsulation layer 116 has a thickness t3. For any additional subpixels 108n, the encapsulation layer 116 has a thickness t nIn one embodiment, the thickness t3 of the encapsulation layer 116 in the subpixel 108c is less than the thicknesses t1 and t2. In another embodiment, the thickness t3 of the encapsulation layer 116 in the subpixel 108c is greater than the thicknesses t1 and t2. In another embodiment, the thickness t3 of the encapsulation layer 116 in the subpixel 108c is less than the thickness t1 and greater than the thickness t2. In another embodiment, the thickness t3 of the encapsulation layer 116 in the subpixel 108c is greater than the thickness t1 and less than the thickness t2. In another embodiment, the thickness of the encapsulation layer 116 increases as the wavelength of the emitted light increases. In another embodiment, the thickness of the encapsulation layer 116 decreases as the wavelength of the emitted light increases.

[0056]

[0065] The thickness, composition, and deposition method of the encapsulation layer 116 can be varied as described above. Varying the composition and deposition method of the encapsulation layer 116 to produce a variation in thickness protects the deposited OLED material 112 from damage during layer deposition, improving process yield and efficiency. Varying the thickness of the encapsulation layer 116 further controls the distance between the lower edge 206 and the top surface of the encapsulation layer 116 (see subpixels 108b and 108c in Figures 1 and 2), and the distance between the encapsulation edge 230 of the encapsulation layer 116 and the top surface 119 of the encapsulation layer 116. Such distance controls the amount of etching and deposition that occurs under the overhang structure 110, providing increased protection of the OLED material 112 in subsequent depositions and etches.

[0057]

[0066] In summary, described herein are devices related to subpixel circuits that can be used in displays (such as organic light emitting diode (OLED) displays), and methods for forming such subpixel circuits. Adjacent overhang structures that define each subpixel of the subpixel circuit of the display are used to form the subpixel circuit using deposition (e.g., using the method of the fifth, sixth, or seventh exemplary embodiment) and to keep the overhang structures in place after the subpixel circuit is formed. Deposition of the OLED material and the cathode can be performed using deposition. The overhang structures define the evaporation angle. That is, the overhang structures are used according to some embodiments for each of the OLED material and the cathode to obtain a shadowing effect during deposition such that the OLED material does not contact the body structure (and in some embodiments the auxiliary cathode) and the cathode contacts the body structure. The encapsulation layer of each of the subpixels is disposed over the cathode so as to extend under at least a portion of each of the adjacent overhang structures and over the sidewalls of each of the adjacent overhang structures. The thickness of the encapsulation layer in each subpixel is varied to protect the previously deposited layers during subsequent etching of the encapsulation layer. The thickness variation can be a decrease, an increase, or depending on the OLED material (e.g., the color of the OLED) that is deposited.

[0058]

[0067] While the above is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, the scope of which is determined by the following claims.

Claims

1. A device, A substrate; a plurality of overhang structures, each overhang structure defined by an upper extension of a superstructure extending laterally beyond the body structure, adjacent overhang structures of the plurality of overhang structures defining a plurality of subpixels including a first subpixel and a second subpixel; The first subpixel is a first organic light emitting diode (OLED) material; a first cathode disposed over the first OLED material; and a first encapsulation layer disposed over the first cathode and extending under the adjacent overhang structure to contact a portion of a sidewall of the adjacent overhang structure, the first encapsulation layer having a first thickness; The second subpixel is a second organic light emitting diode (OLED) material; and a second cathode disposed over the second OLED material; and a second encapsulation layer disposed over the second cathode and extending under the adjacent overhang structure to contact a portion of a sidewall of the adjacent overhang structure, the second encapsulation layer having a second thickness different from the first thickness; device.

2. 10. The device of claim 1, wherein the second encapsulation layer of the second subpixel extends under the adjacent overhang structure and contacts a portion of a sidewall of the body structure and a bottom surface of the superstructure.

3. Further comprising a third sub-pixel, wherein the third sub-pixel comprises: a third organic light emitting diode (OLED) material; and a third cathode disposed over the third OLED material; and 10. The device of claim 1, further comprising: a third encapsulation layer disposed over the third cathode and extending under the adjacent overhang structure to contact a portion of a sidewall of the overhang structure, the third encapsulation layer having a third thickness different from the first thickness and the second thickness.

4. 4. The device of claim 3, wherein the third encapsulation layer of the third subpixel extends under the adjacent overhang structure and contacts a portion of a sidewall of the body structure, a bottom surface of the superstructure, a sidewall of the superstructure, and a top surface of the superstructure.

5. The device of claim 3 , wherein the first encapsulation layer, the second encapsulation layer, and the third encapsulation layer comprise a silicon nitride material, a silicon oxynitride material, a silicon oxide material, or a combination thereof.

6. The device of claim 3 , wherein the first encapsulation layer comprises a different material than at least one of the second encapsulation layer or the third encapsulation layer.

7. The device of claim 1 , wherein the body structure comprises an inorganic material or a metal-containing material.

8. 4. The device of claim 3, wherein the first encapsulation layer, the second encapsulation layer, and the third encapsulation layer comprise at least two layers of silicon-containing material, and wherein the at least two layers of silicon-containing material in at least one of the first encapsulation layer, the second encapsulation layer, and the third encapsulation layer are different from each other.

9. 10. The device of claim 1 , wherein the first OLED material is disposed over and in contact with a first anode and beneath the overhang structure, and the second OLED material is disposed over and in contact with a second anode.

10. A device, A substrate; a plurality of overhang structures, each overhang structure defined by an upper extension of a superstructure that extends laterally beyond the body structure to form an overhang, adjacent overhang structures of the plurality of overhang structures defining a plurality of subpixels including a first subpixel and a second subpixel; The first subpixel is a first organic light emitting diode (OLED) material; a first cathode disposed over the first OLED material; and a first encapsulation layer disposed over the first cathode and extending beneath the adjacent overhang structure to contact a portion of a sidewall of the overhang structure, the first encapsulation layer being within an entire area of the overhang and having a first thickness; The second subpixel is a second organic light emitting diode (OLED) material; and a second cathode disposed over the second OLED material; and a second encapsulation layer disposed over the second cathode and extending under the adjacent overhang structure to contact a portion of a sidewall of the adjacent overhang structure, the second encapsulation layer having a second thickness different from the first thickness; device.

11. In the overhang, a gap exists between the second encapsulation layer on the bottom surface of the superstructure at the overhang and the second encapsulation layer above the second cathode; or 11. The device of claim 10, wherein the gap exists between a lower edge of the superstructure at the overhang and the second encapsulation layer above the second cathode.

12. Further comprising a third sub-pixel, wherein the third sub-pixel comprises: a third organic light emitting diode (OLED) material; and a third cathode disposed over the third OLED material; and 12. The device of claim 11 , comprising: a third encapsulation layer disposed over the third cathode and extending under the adjacent overhang structure to contact a portion of a sidewall of the overhang structure, the third encapsulation layer having a third thickness different from the first thickness and the second thickness.

13. 13. The device of claim 12, wherein the first encapsulation layer, the second encapsulation layer, and the third encapsulation layer comprise a silicon nitride material, a silicon oxynitride material, a silicon oxide material, or a combination thereof.

14. The device of claim 10 , wherein the body structure comprises an inorganic material or a metal-containing material.

15. The device of claim 10 , wherein the superstructure comprises a non-conductive material, an inorganic material, or a metal-containing material.

16. 11. The device of claim 10, wherein the first cathode extends beyond an endpoint of the first OLED material and the second cathode extends beyond an endpoint of the second OLED material.

17. 11. The device of claim 10, wherein the first OLED material is disposed over and in contact with a first anode, and the second OLED material is disposed over and in contact with a second anode.

18. A device, A substrate; a plurality of overhang structures, each overhang structure defined by an upper extension of an upper structure that extends laterally beyond the body structure to form an overhang, adjacent overhang structures of the plurality of overhang structures defining a plurality of subpixels including a first subpixel, a second subpixel, and a third subpixel; The first subpixel is a first organic light emitting diode (OLED) material; a first cathode disposed over the first OLED material; and a first encapsulation layer disposed over the first cathode and extending beneath the adjacent overhang structure to contact a portion of a sidewall of the overhang structure, the first encapsulation layer having a first thickness; The second subpixel is a second organic light emitting diode (OLED) material; and a second cathode disposed over the second OLED material; and a second encapsulation layer disposed over the second cathode and extending beneath the adjacent overhang structure to contact a portion of a sidewall of the overhang structure, the second encapsulation layer having a second thickness different from the first thickness; The third sub-pixel is a third organic light emitting diode (OLED) material; and a third cathode disposed over the third OLED material; and a third encapsulation layer disposed over the third cathode and extending beneath the adjacent overhang structure to contact a portion of a sidewall of the overhang structure, the third encapsulation layer having a third thickness different from the first thickness and the second thickness; device.

19. 20. The device of claim 18, wherein the first thickness of the first encapsulation layer is greater than the second thickness of the second encapsulation layer and the third thickness of the third encapsulation layer, and the second thickness of the second encapsulation layer is greater than the third thickness of the third encapsulation layer.

20. 20. The device of claim 18, wherein the first thickness of the first encapsulation layer is less than the second thickness of the second encapsulation layer and the third thickness of the third encapsulation layer, and the second thickness of the second encapsulation layer is less than the third thickness of the third encapsulation layer.

21. 20. The device of claim 18, wherein the first encapsulation layer, the second encapsulation layer, and the third encapsulation layer comprise a silicon nitride material, a silicon oxynitride material, a silicon oxide material, or a combination thereof.

22. 20. The device of claim 18, wherein the first encapsulation layer has a first refractive index, the second encapsulation layer has a second refractive index different from the first refractive index, and the third encapsulation layer has a third refractive index different from the first refractive index and the second refractive index.

23. 20. The device of claim 18, wherein the body structure comprises an inorganic material or a metal-containing material.

24. 20. The device of claim 18, wherein the first cathode extends beyond an endpoint of the first OLED material and the second cathode extends beyond an endpoint of the second OLED material.

25. 20. The device of claim 18, wherein the first OLED material is disposed over and in contact with a first anode, and the second OLED material is disposed over and in contact with a second anode.

26. A device, A substrate; a plurality of overhang structures, each overhang structure defined by an upper extension of a superstructure extending laterally beyond the body structure, adjacent overhang structures of the plurality of overhang structures defining a plurality of subpixels including a first subpixel and a second subpixel; The first subpixel is a first organic light emitting diode (OLED) material; a first cathode disposed over the first OLED material; and a first encapsulation layer disposed over the first cathode and extending under the adjacent overhang structure to contact a portion of a sidewall of the adjacent overhang structure, the first encapsulation layer comprising at least two layers of a silicon-containing material; The second subpixel is a second organic light emitting diode (OLED) material; and a second cathode disposed over the second OLED material; and a second encapsulation layer disposed over the second cathode and extending under the adjacent overhang structure to contact a portion of a sidewall of the adjacent overhang structure, the second encapsulation layer comprising the silicon-containing material in a different composition than the first encapsulation layer. device.

27. Further comprising a third sub-pixel, wherein the third sub-pixel comprises: a third organic light emitting diode (OLED) material; and a third cathode disposed over the third OLED material; and 27. The device of claim 26, comprising: a third encapsulation layer disposed over the third cathode and extending under the adjacent overhang structure to contact a portion of a sidewall of the overhang structure, the third encapsulation layer having a third thickness different from the first thickness and the second thickness.

28. 28. The device of claim 27, wherein the first thickness of the first encapsulation layer is greater than the second thickness of the second encapsulation layer and the third thickness of the third encapsulation layer, and the second thickness of the second encapsulation layer is greater than the third thickness of the third encapsulation layer.

29. 29. The device of claim 28, wherein the first thickness of the first encapsulation layer is less than the second thickness of the second encapsulation layer and the third thickness of the third encapsulation layer, and the second thickness of the second encapsulation layer is less than the third thickness of the third encapsulation layer.

30. 27. The device of claim 26, wherein the first encapsulation layer is within an entire area of an overhang defined by an upper extension of a superstructure that extends laterally beyond the body structure.

Images