Fabrication Of Thin-Film Encapsulation Layer For Light Emitting Device

• US 20180061719A1
• Filed: 11/02/2017
• Published: 03/01/2018
• Est. Priority Date: 12/12/2013
• Status: Active Grant

• Current Assignee: Kateeva, Inc.
• Original Assignee: Kateeva, Inc.
• Inventors: Vronsky, Eliyahu, Harjee, Nahid
• Granted Patent: US 10,811,324 B2
• Time in Patent Office: Days
• CPC Class Codes: B05C 11/10 Storage, supply or control of liquid or other fluent material; Recovery of excess liquid or other fluent material B05C1/0813, B05C5/0225, B05C17/002 and B05C19/06 take precedence
• CPC Class Codes: B41J 2/01 Ink jet
• CPC Class Codes: B41J 2/04581 controlling heads based on piezoelectric elements
• CPC Class Codes: B41J 2/2054 by the variation of dot disposition or characteristics, e.g. dot number density, dot shape
• CPC Class Codes: B41J 2/21 for multi-colour printing
• CPC Class Codes: B41J 3/407 for marking on special material
• CPC Class Codes: B41M 3/00 Printing processes to produce particular kinds of printed work, e.g. patterns printing apparatus or machines of special type or for particular purposes B41F17/00; special designs or pictures per se B44F; manufacturing printed circuits using printing techniques H05K3/12 ; manufacturing organic semiconductor devices using printing techniques H10K71/13
• CPC Class Codes: B41M 5/0047 by ink-jet printing
• CPC Class Codes: B41M 7/0081 using electromagnetic radiation or waves, e.g. ultraviolet radiation, electron beams
• CPC Class Codes: B41M 7/009 using thermal means, e.g. infrared radiation, heat
• CPC Class Codes: H01L 21/02288 printing, e.g. ink-jet printing per se B41J
• CPC Class Codes: H01L 21/67126 Apparatus for sealing, encapsulating, glassing, decapsulating or the like processes H01L23/02, H01L23/28
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32
• CPC Class Codes: H01L 2933/005 relating to encapsulations
• CPC Class Codes: H01L 31/0203 Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80
• CPC Class Codes: H01L 31/048 Encapsulation of modules
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H04N 1/405 : Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
• CPC Class Codes: H10K 50/84 : Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 50/844 : Encapsulations
• CPC Class Codes: H10K 50/8445 : multilayered coatings having a repetitive structure, e.g. having multiple organic-inorganic bilayers
• CPC Class Codes: H10K 59/1201 : Manufacture or treatment
• CPC Class Codes: H10K 59/8731 : multilayered coatings having a repetitive structure, e.g. having multiple organic-inorganic bilayers
• CPC Class Codes: H10K 71/00 : Manufacture or treatment specially adapted for the organic devices covered by this subclass
• CPC Class Codes: H10K 71/135 : using ink-jet printing
• CPC Class Codes: H10K 71/70 : Testing, e.g. accelerated lifetime tests
• CPC Class Codes: Y02E 10/549 : Organic PV cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

An ink jet process is used to deposit a material layer to a desired thickness. Layout data is converted to per-cell grayscale values, each representing ink volume to be locally delivered. The grayscale values are used to generate a halftone pattern to deliver variable ink volume (and thickness) to the substrate. The halftoning provides for a relatively continuous layer (e.g., without unintended gaps or holes) while providing for variable volume and, thus, contributes to variable ink/material buildup to achieve desired thickness. The ink is jetted as liquid or aerosol that suspends material used to form the material layer, for example, an organic material used to form an encapsulation layer for a flat panel device. The deposited layer is then cured or otherwise finished to complete the process.

Claims

1. An apparatus for fabricating a layer for an electronic device having one or more light emitting elements, the layer to have a desired thickness, the apparatus comprising:

an ink jet printer to receive a substrate, the one or more light emitting elements formed on the substrate, and to print droplets of an organic material onto the substrate, in a manner so as to form a liquid coat over the one or more light emitting elements;

circuitry to control the volume of the liquid printed per unit area of the substrate in dependence on the desired thickness by causing the ink jet printer to vary at least one of a droplet area density or a size of the droplets, in a manner such that a thicker liquid coat is formed by a greater droplet area density or size and a thinner liquid coat is formed by a lesser droplet area density or size, and in a manner where at least one value dependent on the desired thickness is received by the circuitry and used by the circuitry to specify thickness of the liquid coat as deposited; and

a processing mechanism to process the liquid coat once deposited to form the layer from the liquid coat so as to have the desired thickness.

2. The apparatus of claim 1, wherein said apparatus is to produce the layer for each substrate of a series of substrates, and wherein:

each respective substrate comprises an active region, an exposed region and a buffer region between the active region and the exposed region, the active region to receive the layer at a uniform thickness corresponding to the desired thickness, the exposed region not to receive the layer, the buffer region to provide a transition between the active region and the exposed region; and

the buffer region is to receive the layer according to a second volume of the liquid deposited per unit area, relative to the active region.

3. The apparatus of claim 2, wherein the circuitry is to cause the ink jet printer to vary an electronic drive signal supplied to nozzles of a printhead of the ink jet printer, to vary size of the droplets in the buffer region relative to the active region, so as to deposit the second volume of the liquid per unit area.

4. The apparatus of claim 2, wherein the circuitry is to cause the ink jet printer to vary droplet area density provided by droplets ejected from nozzles of a printhead of the ink jet printer, to vary a number of the droplets per unit area in the buffer region relative to the active region, so as to deposit the second volume of the liquid per unit area.

5. The apparatus of claim 4, wherein the circuitry is to cause the ink jet printer to vary the droplet area density by depositing droplets at fewer nodes of a print grid, so as to reduce a spatial frequency at which droplets are deposited in the buffer region relative to the active region.

6. The apparatus of claim 4, wherein the circuitry is to cause the ink jet printer to vary the droplet area density by varying time-dependent frequency of a trigger signal supplied in common to the nozzles of the ink jet printer, so as to vary spatial frequency of the deposition of the droplets in the buffer region relative to the active region.

7. The apparatus of claim 4, wherein the circuitry is to cause the ink jet printer to vary the droplet area density by varying time-dependent frequency of a trigger signal supplied to a first one of the nozzles of the ink jet printer relative to a second one of the nozzles of the ink jet printer, so as to vary spatial frequency of droplets provided by the first one in the buffer region relative to spatial frequency of droplets provided by the second one in the buffer region.

8. The apparatus of claim 2, wherein:

the second volume is to be selected according to a calibration process performed on a test substrate, the calibration process to measure deviation between a lip of a deposited layer and the uniform thickness; and

the second volume of the liquid per unit area is selected so as to reduce the deviation.

9. The apparatus of claim 1, wherein:

the volume of the liquid printed per the unit area comprises a first volume per the unit area;

the one or more electronic elements are to be part of an electronic display panel, the electronic display panel comprising an active region which encompasses a pixelated portion of the electronic display panel, an exposed region and a buffer region between the active region and the exposed region, the active region to receive the layer at a uniform thickness corresponding to the desired thickness, the exposed region not to receive the layer, the buffer region to provide a transition between the active region and the exposed region; and

the buffer region is to receive the layer according to a second volume of the liquid deposited per unit area, relative to the active region, the second volume selected so as to reduce deviation between a lip of the layer and the uniform thickness.

10. The apparatus of claim 1, wherein the organic material comprises a monomer and wherein the processing mechanism comprises a source to expose the liquid coat to radiation to convert the monomer to a polymer.

11. The apparatus of claim 10, wherein the radiation is ultraviolet radiation.

12. The apparatus of claim 1, wherein the organic material comprises a first material and wherein the processing mechanism comprises a source to expose the liquid coat to radiation to convert the first material into a second material, wherein the second material is to be in a solid state following said conversion.

13. The apparatus of claim 1, wherein the one or more light emitting elements comprises at least two independently-controllable light emitting elements, and wherein the layer is to span the at least two independently-controllable light emitting elements.

14. The apparatus of claim 1, wherein said apparatus is to produce the layer for each substrate of a series of substrates, and wherein the ink jet printer is to print the liquid according to a common scan pattern and a common nozzle firing pattern for each of the respective substrates.

15. The apparatus of claim 1, wherein the layer is a thin film layer comprising at least one of an encapsulation layer, or a planarization layer, or a barrier layer.

16. An apparatus for fabricating a layer for an electronic device having one or more light emitting elements, the layer to have a desired thickness, the apparatus comprising:

a gas enclosure to receive a substrate, the one or more light emitting elements to be formed on the substrate;

an ink jet printer within the gas enclosure, the ink jet printer to print droplets of an organic material onto the substrate, in a manner so as to form a liquid coat over the one or more light emitting elements;

circuitry to control the volume of the liquid printed per unit area of the substrate in dependence on the desired thickness by causing the ink jet printer to vary at least one of a droplet area density or a size of the droplets, in a manner such that a thicker liquid coat is formed by a greater droplet area density or size and a thinner liquid coat is formed by a lesser droplet area density or size, and in a manner where at least one value dependent on the desired thickness is received by the circuitry and used by the circuitry to specify thickness of the liquid coat as deposited; and

a processing mechanism to process the liquid coat once deposited to form the layer from the liquid coat so as to have the desired thickness.

17. The apparatus of claim 16, wherein the gas enclosure is to enclose at least one of nitrogen gas or a Noble gas.

18. The apparatus of claim 16, wherein said apparatus is embodied as an apparatus for producing the layer for each substrate of a series of substrates, and wherein:

each respective substrate comprises an active region, an exposed region and a buffer region between the active region and the exposed region, the active region to receive the layer at a uniform thickness corresponding to the desired thickness, the exposed region not to receive the layer, the buffer region providing a transition between the active region and the exposed region; and

the buffer region is to receive the layer according to an second volume of the liquid deposited per unit area, relative to the active region.

19. The apparatus of claim 18, wherein the circuitry is to cause the ink jet printer to vary an electronic drive signal supplied to nozzles of a printhead of the ink jet printer, to vary size of the droplets in the buffer region relative to the active region, so as to deposit the second volume.

20. The apparatus of claim 18, wherein the circuitry is to cause the ink jet printer to vary the droplet area density provided by nozzles of a printhead of the ink jet printer, to vary a number of droplets deposited in the buffer region relative to the active region, so as to deposit the second volume.

21. The apparatus of claim 20, wherein the circuitry is to cause the ink jet printer to deposit the droplets at fewer nodes of a print grid, so as to reduce a spatial frequency at which droplets are deposited in the buffer region relative to the active region.

22. The apparatus of claim 20, wherein the circuitry is to cause the ink jet printer to vary time-dependent frequency of a trigger signal supplied in common to the nozzles of the ink jet printer, so as to vary spatial frequency of the deposition of the droplets in the buffer region relative to the active region.

23. The apparatus of claim 20, wherein the circuitry is to cause the ink jet printer to vary the droplet area density by varying time-dependent frequency of a trigger signal supplied to a first one of the nozzles of the ink jet printer relative to a second one of the nozzles of the ink jet printer, so as to vary spatial frequency of droplets provided by the first one in the buffer region relative to spatial frequency of droplets provided by the second one in the buffer region.

24. The apparatus of claim 16, wherein:

the second volume is to be selected according to a calibration process performed on a test substrate, the calibration process to measure deviation between a lip of a deposited layer and the uniform thickness; and

the second volume is selected so as to reduce the deviation.

25. The apparatus of claim 16, wherein:

the volume of the liquid printed per the unit area comprises a first volume per the unit area;

the electronic device is an electronic display panel, and comprises an active region which encompasses a pixelated portion of the electronic display panel, an exposed region and a buffer region between the active region and the exposed region, the active region to receive the layer at a uniform thickness corresponding to the desired thickness, the exposed region not to receive the layer, the buffer region to provide a transition between the active region and the exposed region; and

the buffer region is to receive the layer according to an second volume of the liquid deposited per unit area, relative to the active region, the second volume selected so as to reduce deviation between a lip of the layer and the uniform thickness.

26. The apparatus of claim 16, wherein the organic material comprises a monomer and wherein the processing mechanism comprises a source to expose the liquid coat to radiation to convert the monomer to a polymer.

27. The apparatus of claim 26, wherein the radiation is ultraviolet radiation.

28. The apparatus of claim 16, wherein the organic material comprises a first material and wherein the processing mechanism comprises a source to expose the liquid coat to radiation to convert the first material into a second material, wherein the second material is to be in a solid state following said conversion.

29. The apparatus of claim 16, wherein the one or more light emitting elements comprises at least two independently-controllable light emitting elements, and wherein the layer is to span the at least two independently-controllable light emitting elements.

30. The apparatus of claim 16, wherein said apparatus is to produce the layer for each substrate of a series of substrates, and wherein the ink jet printer is to print the liquid according to a common scan pattern and a common nozzle firing pattern for each of the respective substrates.

31. The apparatus of claim 16, wherein the layer is a thin film layer comprising at least one of an encapsulation layer, or a planarization layer, or a barrier layer.

32. A method of fabricating a layer for an electronic device having one or more light emitting elements, the layer to have a desired thickness, the method comprising:

receiving a substrate with an ink jet printer, the one or more light emitting elements formed on the substrate, and printing droplets of an organic material onto the substrate, in a manner so as to form a liquid coat over the one or more light emitting elements;

using circuitry to control the volume of the liquid printed per unit area of the substrate in dependence on the desired thickness by causing the ink jet printer to vary at least one of a droplet area density or a size of the droplets, in a manner such that a thicker liquid coat is formed by a greater droplet area density or size and a thinner liquid coat is formed by a lesser droplet area density or size, and in a manner where at least one value dependent on the desired thickness is received by the circuitry and used by the circuitry to specify thickness of the liquid coat as deposited; and

using a processing mechanism to process the liquid coat once deposited to form the layer from the liquid coat so as to have the desired thickness.

33. The method of claim 32, embodied as a method of fabricating the layer for each substrate of a series of substrates, wherein:

each respective substrate comprises an active region, an exposed region and a buffer region between the active region and the exposed region, the active region to receive the layer at a uniform thickness corresponding to the desired thickness, the exposed region not to receive the layer, the buffer region to provide a transition between the active region and the exposed region; and

the buffer region is to receive the layer according to a second volume of the liquid deposited per unit area, relative to the active region.

34. The method of claim 33, wherein the method further comprises causing the ink jet printer to vary an electronic drive signal supplied to nozzles of a printhead of the ink jet printer, to vary size of the droplets in the buffer region relative to the active region, so as to deposit the second volume of the liquid per unit area.

35. The method of claim 33, wherein the method further comprises causing the ink jet printer to vary droplet area density provided by droplets ejected from nozzles of a printhead of the ink jet printer, to vary a number of the droplets per unit area in the buffer region relative to the active region, so as to deposit the second volume of the liquid per unit area.

36. The method of claim 35, wherein the method further comprises causing the ink jet printer to vary the droplet area density by depositing droplets at fewer nodes of a print grid, so as to reduce a spatial frequency at which droplets are deposited in the buffer region relative to the active region.

37. The method of claim 35, wherein the method further comprises causing the ink jet printer to vary the droplet area density by varying time-dependent frequency of a trigger signal supplied in common to the nozzles of the ink jet printer, so as to vary spatial frequency of the deposition of the droplets in the buffer region relative to the active region.

38. The method of claim 35, wherein the method further comprises causing the ink jet printer to vary the droplet area density by varying time-dependent frequency of a trigger signal supplied to a first one of the nozzles of the ink jet printer relative to a second one of the nozzles of the ink jet printer, so as to vary spatial frequency of droplets provided by the first one in the buffer region relative to spatial frequency of droplets provided by the second one in the buffer region.

39. The method of claim 32, wherein:

the second volume is to be selected according to a calibration process performed on a test substrate, the calibration process to measure deviation between a lip of a deposited layer and the uniform thickness; and

the second volume of the liquid per unit area is selected so as to reduce the deviation.

40. The method of claim 32, wherein:

the volume of the liquid printed per the unit area comprises a first volume per the unit area;

the one or more electronic elements are to be part of an electronic display panel, the electronic display panel to be formed to have an active region which encompasses a pixelated portion of the electronic display panel, an exposed region and a buffer region between the active region and the exposed region, the active region to receive the layer at a uniform thickness corresponding to the desired thickness, the exposed region not to receive the layer, the buffer region to provide a transition between the active region and the exposed region; and

the buffer region is to receive the layer according to a second volume of the liquid deposited per unit area, relative to the active region, the second volume selected so as to reduce deviation between a lip of the layer and the uniform thickness.

41. The method of claim 32, wherein the organic material comprises a monomer and wherein the method further comprises irradiating expose the liquid coat with a source to convert the monomer to a polymer.

42. The method of claim 41, wherein the radiation is ultraviolet radiation.

43. The method of claim 32, wherein the organic material comprises a first material and wherein the method further comprises exposing the liquid coat to a source to convert the first material into a second material, wherein the second material is to be in a solid state following said conversion.

44. The method of claim 32, wherein the one or more light emitting elements comprises at least two independently-controllable light emitting elements, and wherein the layer is to span the at least two independently-controllable light emitting elements.

45. The method of claim 32, wherein said method is embodied as a method of producing the layer for each substrate of a series of substrates, and wherein the ink jet printer is to print the liquid according to a common scan pattern and a common nozzle firing pattern for each of the respective substrates.

46. The method of claim 32, wherein the layer is a thin film layer comprising at least one of an encapsulation layer, or a planarization layer, or a barrier layer.