Ink-based layer fabrication using halftoning to control thickness

• US 8,995,022 B1
• Filed: 08/12/2014
• Issued: 03/31/2015
• Est. Priority Date: 12/12/2013
• Status: Active Grant

• Current Assignee: Kateeva, Inc.
• Original Assignee: Kateeva, Inc.
• Inventors: Vronsky, Eliyahu, Harjee, Nahid
• Primary Examiner(s): Rogers, Scott A
• Application Number:
  US14/458,005
• Time in Patent Office: 231 Days
• Field of Search: None
• US Class Current: 358/3.06
• 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. A method of forming a layer over a substrate, the method comprising:

receiving data identifying a desired thickness of the layer;

using a processor to generate instructions for a printing mechanism to deposit droplets of ink onto the substrate according to the data, the ink carrying material to form the layer; and

wherein using the processor comprises selecting a halftone pattern in dependence on the desired thickness and generating the instructions dependent on the selected halftone pattern.

2. The method of claim 1, wherein the data includes at least one thickness value, wherein generating the instructions includes converting the at least one thickness value to a grayscale value for each one of plural print cells and selecting the halftone pattern dependent on the grayscale values for the plural print cells.

3. The method of claim 2, wherein generating the instructions further comprises adjusting the grayscale value for selective ones of the plural print cells.

4. The method of claim 3, wherein adjusting the grayscale value for selective ones of the plural print cells includes doing so dependent on proximity to an edge of the layer.

5. The method of claim 1, wherein using the processor includes dividing a substrate deposition area into plural deposition regions and selecting a halftone pattern for each of the plural deposition regions, and wherein the halftone patterns for adjacent ones of the plural deposition regions are selected to have complementary droplet patterns.

6. The method of claim 1, wherein the method further comprises using the printing mechanism to jet droplets of a liquid to deposit the layer, including jetting substantially like-sized droplets at variable spatial frequency to influence the desired thickness.

7. The method of claim 1, wherein:

the layer is a first layer;

the substrate comprises at least one active element and an underlying support surface;

the at least one active element includes a second layer having a first face abutting the first layer, a second face on a side of the second layer opposite the first layer, and lateral edges; and

the method further comprises using the printing mechanism to deposit the first layer as an encapsulation layer that encloses the first face, the second face and the lateral edges relative to the underlying support surface, to enclose the second layer against an external atmosphere.

8. The method of claim 7, wherein using the printing mechanism comprises controlling an atmosphere containing the substrate during deposition of the encapsulation layer.

9. The method of claim 1, wherein:

the layer is an encapsulation layer;

the substrate comprises a target region that is to be covered with the encapsulation layer and an exposed region that is not to be covered with the encapsulation layer; and

the method further comprises using the printing mechanism comprises to deposit the encapsulation layer in the target region but not the exposed region according to the halftone pattern.

10. The method of claim 9, wherein:

the substrate further comprises a border region of the target region proximate to the exposed region; and

using the processor comprises adjusting a grayscale value for a print cell representing a subset of the substrate, where the print cell corresponds to the border region.

11. The method of claim 9, wherein

the substrate further comprises a border region of the target region proximate to the exposed region;

and

using the processor further comprises selecting a halftone pattern for at least one print cell corresponding to the border region that emphasizes density of droplets at a periphery of the target region which abuts the exposed region.

12. The method of claim 9, applied as a method of fabricating a device, wherein the substrate supports active electronic elements within the target region that are to be encapsulated by the encapsulation layer, electrical contacts in the exposed region that are not to be encapsulated by the encapsulation layer, and conductive paths coupling the electrical contacts with respective ones of the active electronic elements.

13. The method of claim 9, wherein:

using the printing mechanism comprises controlling an atmosphere containing the substrate during deposition of the encapsulation layer; and

the method further comprises forming, prior to using the printing mechanism to deposit the encapsulation layer, the electronic devices, also in presence of a controlled atmosphere, wherein the forming and the using are performed in a manner uninterrupted by exposure to an uncontrolled atmosphere.

14. The method of claim 13, wherein the atmosphere containing the substrate during deposition and the controlled atmosphere are different.

15. The method of claim 9, wherein:

the encapsulation layer is an organic encapsulation layer; and

using the printing mechanism to deposit the organic encapsulation layer comprises using an ink jet printing mechanism to deposit the material to form the layer, the material comprising at least one of a liquid monomer, a liquid polymer or a solvent having an organic material suspended therein.

16. The method of claim 1, wherein the method further comprises analyzing a prior layer formation, comparing the prior layer formation with a target layer thickness, responsively updating at least one of grayscale values for plural print cells or the halftone pattern dependent on a result of the comparing, and storing an updated halftone pattern in machine-readable memory.

17. The method of claim 1, embodied as a method of fabricating a flat panel television.

18. The method of claim 1, embodied as a method of fabricating a solar panel.

19. The method of claim 1, wherein:

using the processor includes

dividing an area representing the substrate into print cells, and

assigning a grayscale value to each of the print cells; and

selecting the halftone pattern comprises selecting the halftone pattern dependent on plural ones of the print cells to deposit ink at a density dependent on the grayscale values for the plural ones of the print cells.

20. The method of claim 1, further comprising retrieving nozzle-specific droplet ejection parameters from machine-readable memory and adjusting a print pattern in dependence on the retrieved nozzle-specific droplet ejection parameters.

21. The method of claim 1, wherein receiving the data further comprises receiving layout data, the layout data including the data identifying the desired thickness as well as data defining contours of the layer.

22. A method of forming a flat panel display, the method comprising:

receiving data identifying a desired thickness of a layer to be deposited over a substrate, the layer to form part of the flat panel display;

using a processor to select a halftone pattern dependent on the desired thickness, the halftone pattern representing a relatively more dense droplet pattern for a relatively thicker layer and a relatively less dense droplet pattern for a relatively thinner layer; and

causing an ink jet printing mechanism to deposit droplets of ink onto the substrate according to the halftone pattern, the ink carrying material to form the layer.

23. The method of claim 22, wherein the ink comprises an organic material.

24. The method of claim 22, wherein causing the ink jet printing mechanism to deposit droplets of ink includes controlling the ink jet printing mechanism to deposit the droplets in the presence of a controlled atmosphere.

25. The method of claim 22, wherein the flat panel display is an organic light emitting diode (“

OLED”

) display device layer and wherein the layer is an encapsulation layer of the OLED display device.

26. The method of claim 25, embodied as a method of fabricating a flat panel television.

27. A method of forming a flat panel electronic device, comprising:

receiving at least one thickness value associated with a desired layer to be deposited over an area of substrate;

using at least one processor to generate a grayscale value for each one of plural print cells associated with the area of the substrate, each grayscale value dependent on a thickness value of the at least one thickness value;

using the at least one processor to select at least one halftone pattern dependent on the grayscale values; and

using the at least one processor to generate printer control instructions to fabricate the desired layer by jetting ink droplets according to the at least one halftone pattern, the desired layer having thickness dependent on each halftone pattern selected dependent on the grayscale values.

28. An apparatus comprising executable instructions stored on non-transitory machine-readable media, the executable instructions when executed to cause at least one processor to:

receive data identifying a desired thickness of the layer;

generate control instructions for a printing mechanism to deposit droplets of ink onto the substrate according to the data, the ink carrying material to form the layer; and

wherein the executable instructions are when executed to cause the at least one processor to select a halftone pattern in dependence on the desired thickness and to generate the control instructions dependent on the selected halftone pattern.

29. The apparatus of claim 28, wherein the data includes at least one thickness value, wherein the executable instructions are when executed to cause the at least one processor to convert the at least one thickness value to a grayscale value for each one of plural print cells and to select the halftone pattern dependent on the grayscale values for the plural print cells.

30. The apparatus of claim 28, wherein the executable instructions are when executed to cause the at least one processor to adjust the grayscale value for selective ones of the plural print cells, dependent on proximity to an edge of the layer.