METHOD FOR DEPOSITION OF HIGH-PERFORMANCE COATINGS AND ENCAPSULATED ELECTRONIC DEVICES

• US 20130334511A1
• Filed: 06/13/2013
• Published: 12/19/2013
• Est. Priority Date: 06/13/2012
• Status: Active Grant

• Current Assignee: Aixtron AG
• Original Assignee: PlasmaSi, Inc. (Aixtron AG)
• Inventors: Wiesnoski, Allan, Chatham, Hood, Galewski, Carl, Savas, Stephen E.
• Granted Patent: US 9,299,956 B2
• Time in Patent Office: Days
• US Class Current: 257/40
• CPC Class Codes: H01L 31/02167 for solar cells
• CPC Class Codes: H01L 31/048 Encapsulation of modules
• CPC Class Codes: H10K 50/8445 multilayered coatings having a repetitive structure, e.g. having multiple organic-inorganic bilayers
• 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: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A method is disclosed for forming leak-free coatings on polymeric or other surfaces that provide optical functions or protect underlying layers from exposure to oxygen and water vapor and do not crack or peel in outdoor environments. This method may include both cleaning and surface modification steps preceding coating. The combined method greatly reduces defects in any barrier layer and provides weatherability of coatings. Specific commercial applications that benefit from this include manufacturing of photovoltaic devices or organic light emitting diode devices (OLED) including lighting and displays.

Claims

1. A method for forming moisture and oxygen permeation barriers on electronic devices on rectangular or continuous web substrates comprising:

the substrate, while being maintained in a temperature range below 100°

C., is subjected to a substrate surface modification step forming a first layer upon said device, including both plasma enhanced chemical vapor deposition of a transparent dielectric material and sputter etching of said transparent dielectric material on the substrate surface by a plasma adjacent the substrate; and

the substrate supporting the electronic device is then subjected to the plasma enhanced chemical vapor deposition process with the substrate temperature maintained below about 100°

C. of a second layer that is a transparent dielectric material to form a hermetic barrier layer.

2. A method as in claim 1 wherein the hermetic barrier layer contains silicon nitride.

3. A method as in claim 1 wherein the electronic device is an OLED device that is subjected to the plasma enhanced deposition of both the first layer and the second layer.

4. A method as in claim 1 wherein the electronic device is subjected to the plasma enhanced chemical vapor deposition process producing a four layer coating wherein a third layer is substantially the same material as the first layer and deposited by a process substantially as used for depositing the first layer, and a fourth layer is substantially the same material as the second layer and deposited by a process substantially as used for depositing the second layer.

5. A method for forming moisture and oxygen barriers on electronic devices on large rectangular or continuous web substrates wherein the substrate or web is processed as it moves through the processing system continuously comprising:

the surface cleaned by a cryogenic spray cleaning process using at least one of;

argon, nitrogen and carbon dioxide to form a cleaned surface;

the cleaned surface subjected to a surface modification step having both plasma enhanced chemical vapor deposition of transparent material onto the cleaned surface and sputter etching of the transparent material on the cleaned surface; and

the substrate is then subjected to plasma enhanced chemical vapor deposition of a transparent hermetic barrier layer with the substrate temperature maintained below about 150°

C. during the plasma enhanced chemical vapor deposition of a transparent hermetic barrier layer.

6. A method as in claim 5 wherein the hermetic barrier layer contains silicon nitride.

7. A method as in claim 5 wherein an OLED device is coated with a moisture protective coating.

8. A method as in claim 5 for depositing a four layer coating wherein a third layer is deposited using substantially the same material and process as used for depositing the first layer, and a fourth layer is deposited using substantially the same material and process as used for depositing the second layer.

9. A method for forming very low defect moisture and oxygen barriers on a rectangular or continuous web substrate in which the substrate or web is processed in a series of steps comprising:

the substrate, while being maintained in a temperature range below about 100°

C., is subjected to a surface modification step including both plasma enhanced chemical vapor deposition of transparent material and substantial sputter etching of the material on a surface of the substrate by an rf biased plasma adjacent the substrate, the transparent material having a thickness after the surface modification step, the transparent material having a surface topography that is smoothed; and

the substrate is then subjected to a plasma enhanced chemical vapor deposition process of a transparent dielectric material having less than 3% carbon content with the substrate temperature maintained below about 100°

C.

10. A method as in claim 9 wherein the hermetic barrier layer contains silicon nitride.

11. A method as in claim 9 wherein an OLED device is covered with a moisture protective coating.

12. A method as in claim 9 for depositing a four layer coating wherein a third layer is deposited using substantially the same material and process as used for depositing the first layer, and a fourth layer is deposited using substantially the same material and process as used for depositing the second layer.

13. A method for forming defect-free moisture and oxygen barriers on a rectangular or continuous web substrate in which the substrate is processed in a series of steps comprising:

the substrate, while being maintained in a temperature range below about 100°

C., is subjected to plasma enhanced chemical vapor deposition of between 20 nm and 300 nm of transparent oxide or oxynitride dielectric material that contains at most 3% carbon; and

the substrate is then subjected to a plasma enhanced chemical vapor deposition process of a transparent nitrogen-containing material with thickness from 50 nm to 1000 nm having less than 3% carbon content with the substrate temperature maintained below about 90°

C.

14. A method as in claim 13 wherein the hermetic barrier layer contains silicon nitride.

15. A method as in claim 13 wherein an OLED device is covered with a moisture protective coating.

16. A method as in claim 13 for depositing a four layer coating wherein a third layer is deposited using substantially the same material and process as used for depositing the first layer, and a fourth layer is deposited using substantially the same material and process as used for depositing the second layer.

17. A hermetic encapsulated Organic Light Emitting Diode (OLED) device on a rectangular or continuous web substrate comprising:

a substrate supporting a multi-layer structure including a lower conductive layer, a hole transport layer, an Organic Light Emitting Diode layer, an electron transport layer, and an upper transparent conductive layer;

above said multi-layer structure is at least a first layer of a dense, transparent dielectric material that has been deposited on the surface and subjected to sputter etching;

thereupon said first layer is a second layer, a hermetic barrier film, that is substantially transparent to visible light and contains nitrogen and between 1% to 3% carbon, and at least one of;

silicon, aluminum, zinc, or tin.

18. The device of claim 17 wherein said first layer has an average thickness between 10 nm and 100 nm.

19. The device of claim 17 wherein the hermetic barrier film is substantially silicon nitride.

20. A hermetic encapsulated CIGS device on a rectangular or continuous web substrate comprising:

a substrate supporting a CIGS photovoltaic device;

above a topmost conductive layer of said device is a first layer of transparent dielectric material with thickness less than 100 nm whose upper surface is smoother than the surface upon which it is deposited; and

upon said first layer transparent dielectric material is a second layer, a hermetic barrier film, that is transparent to visible light and contains silicon oxynitride.

21. A hermetic encapsulated CIGS device on a rectangular or continuous web substrate comprising:

the substrate supports a lower conductive layer above which is a CIGS photovoltaic layer, above which is at least one additional conductive layer, at least one of said lower or said at least one conductive layers is transparent;

above a topmost conductive layer is at least one layer of transparent dielectric material having refractive index from 1.4 to 1.5, which contains silicon oxide and between 1% and 3% carbon, and serves as a smoothing layer to reduce surface slope to less than about 70 degrees; and

upon said transparent dielectric material is at least one layer of hermetic barrier film that is transparent to visible light, has refractive index between 1.8 and 2.5, contains nitrogen, and contains at least one of;

silicon, aluminum, zinc, or tin;

wherein layers of transparent materials above the CIGS layer in combination have less than 5% reflected light in the visible wavelength range between 400 nm and 700 nm.

22. A hermetic encapsulated Organic Light Emitting Diode (OLED) device on a rectangular or continuous web substrate comprising:

a substrate supporting a multi-layer structure including a lower conductive layer, a hole transport layer, an Organic Light Emitting Diode layer and an electron transport layer;

above said multi-layer structure is at least a first layer of a dense, transparent dielectric material whose upper surface is smoother than the surface it covers; and

upon said first layer is a second layer, a hermetic barrier layer, that is largely transparent to visible light, and contains silicon and nitrogen.

23. A device as in claim 22 wherein the layer thicknesses are less than 1000 nm.

24. A device as in claim 22 wherein there is a third layer, upon the second layer, and having the same composition and properties as the first layer, and a fourth layer, upon the third layer, having the same composition and properties as the second layer.

25. A device as in claim 24 wherein the first and third layers are between 10 nm and 100 nm thick and the second and fourth layers are between 100 nm and 1000 nm thick.

26. A device as in claim 22 wherein the first layer is substantially silicon oxynitride.

27. A device as in claim 22 wherein the second layer is mostly silicon nitride.