TWI634686B - Hydrophobic bank - Google Patents

Abstract

The invention discloses a method for fabricating an electronic device having an electrically insulating bank structure including a sidewall defining a well, the method comprising: forming the bank structure such that the sidewall includes a first inclined surface extending from a surface layer region and from the first A second steeper slope extending from an inclined surface, the side wall having a discontinuity in surface energy at a point where the second inclined surface is spaced from the first inclined surface; by depositing a solution of an organic semiconductive material in the well Forming a layer structure having at least one layer including the material, wherein the deposited solution wets the first bevel and the second bevel to a pinning point at the surface energy discontinuity; and drying the deposited solution.

Description

Hydrophobic bank

The present invention generally relates to a method for fabricating an electronic device including a substrate having a surface layer and a bank structure defining a well on the surface layer, and a method including a bank structure having a surface layer and defining a well on the surface layer. Electronic device of substrate.

Extensive research has been conducted on methods for manufacturing electronic devices involving deposition of active components from solution (solution treatment). If the active components are deposited from a solution, they are preferably contained in a desired region of the substrate. This can be achieved by providing a substrate including a patterned bank layer defining a well in which an active component can be deposited from a solution. The wells contain the solution as the solution becomes dry, so that the active component remains in the area of the substrate defined by the wells.

These methods have been found to be particularly useful for depositing organic materials from solution. The organic materials may be conductive, semi-conductive, and / or photoactive, such that they can emit light when a current is passed or detect light by generating a current when the light is irradiated thereon. Devices using these materials are called organic electronic devices. If the organic material is a light emitting material, the device is referred to as an organic light emitting device (OLED). In addition, solution processing allows low-cost, low-temperature manufacturing of thin-film transistors (TFTs), and particularly organic thin-film transistors (OTFTs). In such devices, it is particularly desirable to include organic semiconductors (OSCs) in the expedient area, and in particular, the channels of the devices, and banks can be provided that define wells to contain the OSCs.

Some devices may require more than a single solution-deposited layer. A typical OLED, such as that used in displays, may have two layers of organic semiconductor materials, one of which may be A light emitting material layer such as a light emitting polymer (LEP), and the other may be a hole transporting material layer such as a polythiophene derivative or a polyaniline derivative.

An advantageous simple bank structure has a single material / layer that is designed to again contain all such deposited liquids. However, for devices with a single bank material and a single pinning point for all deposited liquids, there is a risk of electrical leakage paths or short circuits between the electrodes on either side of the solution deposited layer. For example, in an OLED structure including an anode-HIL-IL-EL-cathode structure, a leakage current may flow between the anode and the cathode via a leakage path on the boundary of the HIL. Similarly, the leak path can be caused by the cathode in direct contact with the hole injection layer (HIL) on the bank, the point where the very thin device stacks on the bank or the pinned points. The JV (current density-voltage) curve of a fully printed device can, for example, exhibit high leakage (high current) when driven in reverse and / or before switching on. With the spin-coated intermediate layer (IL) and the electroluminescent layer (EL), the leakage is much lower because the HIL is completely covered by the spin-coated film on top. Can lead to much lower efficiency.

Currently, low-leakage devices often require a dual bank system to separate the anode pinning point from the cathode. However, a single bank can reduce complexity compared to a dual bank structure. Additionally or alternatively, a single bank patterned by means of light lithography can provide an inexpensive method for pixel (bank) definition. However, this bank can expose the anode region to hydrocarbons (resist residues) and / or provide a single fluid pinning point for all solution-treated layers (HIL, IL, and EL). It has been shown that a highly conductive HIL plus a short circuit path length between the anode (ITO) surface and the HIL-IL-EL-cathode pinning point will result in a high leakage device.

Similarly, a light emitting device having a bank structure may have poor color uniformity and / or luminous efficiency across the active area.

Therefore, there is a need to provide an improved structure that allows different liquids to be contained in a well and / or a process for making such a structure. The improved structure may have advantages such as any one or more of the following: inter alia, improved color uniformity across the device, lower and / or tunable electrical leakage, increased coverage across the device's active area Total power efficiency and / or efficiency Rate uniformity, (e.g., OLED emission), improved lifetime stability (preferably, for example, more stable and / or more repeatable device illumination during lifetime testing), more compact devices, and The ability to reduce structural complexity and / or make it with fewer processing steps (any of which can lead to improved time or cost efficiency in device manufacturing, improved device yield, repeatability, can (for example ) Reduced requirements on the volume and / or number of constituent materials that result in reduced costs).

Reference is made to the following disclosure for use in understanding the present invention:-US 8,063,551 (Du Pont);-US2006 / 197086 (Samsung Electronics Co Ltd.);-US2010 / 271353 (Sony Corporation (Sony Corp));-WO2009042792 (Inventor Tsai Yaw-Ming A et al.);-US2007 / 085475 (Semiconductor Energy Lab);-US7799407 (Seiko Epson Corp);- US7604864 (Dainippon Screen MFG);-WO9948339 (Seiko Epson Corporation);-JP2007095425A (Seiko Epson Corporation);-WO 2009/077738 (PCT / GB2008 / 004135, June 25, 2009 Disclosed, the inventors are Burroughes and Dowling); and-WO2011 / 070316 A2 (PCT / GB2010 / 002235, published on June 16, 2011, the inventors are Crankshaw and Dowling).

The invention relates to a method for manufacturing an electronic device having an electrically insulating bank structure including a sidewall defining a well, the method comprising: forming the bank structure such that the sidewall includes a first inclined surface extending from a surface layer region and Second steeper slope extending from first slope Surface, the side wall has a discontinuity in surface energy at a point spaced from the second slope to the first slope; forming at least one material including the material by depositing a solution of an organic semiconductive material in the well The layer structure of the layer, wherein the deposited solution wets the first inclined surface and the second inclined surface to a pinning point at the surface energy discontinuity; and the deposited solution is dried.

According to a first aspect of the present invention, there is provided a method for fabricating an electronic device including a substrate having a surface layer and a bank portion structure defining a well on the surface layer, the bank portion structure including an electrically insulating material and having a surface layer surrounding the surface layer. An area to thereby define the sidewall of the well, the surface layer area including the first electrode, and the device further including a second electrode and a semi-conductive material disposed between the first electrode and the second electrode, the The method includes: forming the bank structure having the side wall including a first inclined surface extending from the surface layer region and a second inclined surface extending from the first inclined surface, wherein the second inclined surface is steeper than the first inclined surface, wherein the The side wall has a discontinuity in surface energy at a point spaced apart from the first slope; the layer structure having at least one layer is disposed between the first electrode and the second electrode And having the semi-conductive material, wherein forming the layer structure includes: depositing an organic solution on the surface layer region and the first inclined surface and the second inclined surface of the sidewall to form a This layer of processing liquid, wherein the organic solution was deposited wets the first inclined surface and the second inclined surface until the staple of the discontinuity of the surface energy of tie points; and drying the deposited organic solution.

Therefore, embodiments may provide a pinning point for at least one solution-treatable layer (preferably, the plurality of solution-treatable layers are all pinned at the same point), so that the pinning point is provided by Paths with different slopes that deviate from the straight line are separated from the surface layer region. This can reduce the risk of leakage paths or short circuits between electrodes (eg, anode and cathode) on either side of the solution-deposited layer. For example, in an OLED structure including an anode-HIL-IL-EL-cathode structure, any leakage path between the anode and the cathode along the boundary of a preferably high-resistance HIL is extended. The extended path preferably has a sufficiently high resistance Efforts to prevent leaks that could significantly degrade, for example, efficiency, reliability and / or service life, color variations, and the like.

Considering the resulting device structure more specifically, it should be noted that the surface is preferably formed by the (several) process steps that create the boundary between the wet (e.g., hydrophilic) area and the non-wet (e.g., hydrophobic) area. Energy discontinuities. This boundary is preferably at the top of the second bevel. The top of the second inclined surface is preferably adjacent to a relatively flat surface of the bank structure, and the flat surface is opposite to and parallel to the surface layer. In any case, the surface energy discontinuity is preferably far away from the first bevel and thus away from the surface layer region.

The method may include: depositing at least another solution (eg, EL (light emitting layer) and / or IL (intermediate layer)) over the solution-treatable layer, wherein the at least another solution is wetted to the pinning point; and Dry the deposited at least another solution. Therefore, a plurality of these solution-treatable layers may have the same pinning point.

The method may be further provided, wherein the forming the bank structure includes: forming a first bank layer including a photoresist on the surface layer of the substrate; light patterning and developing the first bank layer to expose the surface Depositing the fluorinated photoresist solution on the exposed area of the first bank layer and the surface layer to form a second bank layer; baking to harden the second bank layer Wherein the fluorine-containing compound of the fluorinated photoresist solution migrates to the surface of the second bank layer during the baking to increase the contact angle between the organic solution and the surface; and photo-patterning and developing the second bank Layer to re-expose the area of the surface layer and the area of the first bank layer, so that the first bank layer area has the first slope and the second bank layer has the second slope, wherein The increased contact angle is higher than the contact angle of the organic solution with the first inclined surface and the second inclined surface, and the pinning point is at the boundary of the surface of the second bank layer layer with the migrated fluorine-containing compound. The surface to which these compounds migrate during this baking may generally be referred to as a "free surface", that is, interfacing with the external environment (eg, air). As in any embodiment using the fluorinated photoresist, the photoresist may be supplied by a photoresist manufacturer for fluorination, or the process may have the addition of a fluorinated compound to a non-fluorinated compound. Photoresist Extra Step. In any case, after the second bank layer has hardened, the second bank layer preferably includes a higher fluorine-containing compound concentration than the first bank layer. In addition, after the second bank layer has been developed to remove a portion of the second bank layer, a portion of the portion that was previously a "free surface" preferably has the second bank exposed by the removal. Wetting / unwetting boundary of the edge of the sublayer, this edge being part of the side wall. Therefore, in addition to the double inclined sidewalls, pinning points can also be formed.

The method may be further provided, wherein forming the bank structure may include forming a bank structure layer by depositing a fluorinated photoresist solution on the surface layer, and drying the deposited solution to make the bank structure layer Hardening, wherein the fluorinated compound of the fluorinated photoresist solution migrates to the surface of the bank structure layer during the baking to increase the contact angle between the organic solution and the surface; and deposits on the bank structure layer and The photoresist layer is dried, and the photoresist layer is patterned and developed. A dry etching step is used to etch the bank structure layer through the developed photoresist layer to expose the surface layer area, so that the process Etching the bank structure layer has the side wall surrounding the exposed surface layer region and includes the first and second slopes; and removing the developed photoresist layer to expose the surface of the bank structure layer, the process The exposed surface includes the migrated fluorine-containing compound, wherein the surface energy discontinuity is at an interface between the exposed surface including the migrated fluorine-containing compound and the etched sidewall. The dry etching step may include reactive ion etching, preferably using an oxygen plasma. Similar to the above, the portion that was previously the "free surface" portion of the bank layer preferably has a wetting / edge of the bank layer that is exposed by development of the portion of the bank layer removed Unwet boundary, this edge is part of the side wall. Therefore, in addition to the double inclined sidewalls, pinning points can also be formed.

The method may be further provided, wherein the forming the bank structure may include developing and photo-patterning the bank structure layer to expose a surface layer region surrounded by a sidewall of the bank structure layer, wherein the at the bank portion Depositing the photoresist layer on the structure layer includes depositing a photoresist solution on the photopatterned bank structure layer, and developing the photoresist layer includes re-exposing The surface layer region, and the dry etching step for exposing the surface layer region extends the exposed region by thinning the bank structure layer to thereby form the first inclined surface and the second inclined surface.

The method may be further provided, wherein the photo-patterning the photoresist layer may include passing through a region having substantially non-transmittance, a partially transmissive region, and a substantially fully transmissive region (at least having a size greater than the partially transmissive region) The photoresist layer is radiated by a mask of (transmittance); and developing the photoresist layer includes completely removing the photoresist area and partially removing the photoresist that is exposed to the radiation through the partially transmissive area. region.

The method may be further provided, wherein the forming the bank structure comprises: forming a bank layer by depositing a fluorinated photoresist solution on the surface layer; and baking to harden the bank layer, wherein The fluorine compound of the photoresist solution migrates to the surface of the bank layer during the baking to thereby increase the contact angle between the organic solution and the surface; the light patterning of the hardened bank layer includes: A first radiation dose irradiates a first area of the bank layer and a second radiation dose irradiates a second area of the bank layer, the second radiation dose is less than the first radiation dose; developing the bank layer to expose the surface The area of the layer and partially removes the area of the bank layer irradiated by the second radiation dose, the partial removal thereby providing a sidewall surrounding the exposed area and having a first slope and a second slope, wherein the The pinning point is at the boundary between the surface of the bank layer and the sidewall with the migrated fluorine-containing compounds. The first region may be above the surface region or above a portion of the bank structure to be retained, depending on whether a negative photoresist or a positive photoresist is used. The portion removes the area of the bank layer that preferably thins to an area of the surface layer to give a longer length along the side wall and therefore along the edge of the solution-treatable layer to be deposited in the well. Path length bracket structure.

The method may be further provided, wherein the light patterning includes radiating the bank layer through a first mask and a second mask simultaneously, wherein irradiating the first region with the first dose includes passing through the first mask The fully transmissive region of the mask and the second mask radiates the first region, And, irradiating the second region with the second dose includes radiating the second region through at least a portion of a transmissive region of each of the first mask and the second mask. The at least partially transmissive region may include a fully transmissive region of the first mask and / or a partially transmissive region of the second mask. At least one of these regions is preferably a partially transmissive region with a transmission gradient.

The method may be further provided, wherein: the light patterning includes radiating the bank layer through a mask having a partially transmissive region and more (preferably, completely) a transmissive region, wherein the radiation is emitted at the first dose The first region includes radiating the first region through the more transmissive region, and the radiating the second region at the second dose includes radiating the second region through the partially transmissive region.

The method may be further provided, comprising depositing a reflector layer on a region of the surface layer, wherein: depositing the fluorinated photoresist solution, depositing the fluorinated solution on the reflector layer and the surface layer; and the Light patterning includes radiating the bank layer through a mask, wherein the first region of the radiation includes the first region absorbing a portion of the first dose received directly through the mask and receiving from the first mask. A part of the dose in the first region is reflected back by the reflector layer.

The method may be further provided, wherein the electronic device is an optoelectronic device such as a light emitting device or a light absorbing device, preferably a light absorbing device such as an organic photovoltaic device (OPV; for example, a solar cell) or an organic light emitting diode (OLED) ) 的 luminescent device. Alternatively, the device is a thin film transistor.

The method may be further provided, wherein the electronic device is an organic light emitting diode and the organic solution is used to provide a hole injection layer (HIL). In addition, at least another solution-treatable layer may be formed on the solution-treatable layer and between the first electrode and the second electrode, and the other solution-treatable layer is used to separately provide an intermediate layer ( IL) and / or light emitting layer (EL).

The method may be further provided, wherein the organic solution is deposited on the first inclined surface and The contact angle when extending from the first inclined plane to at least one of the second inclined plane regions of the pinning point is 10 ° or less. This contact angle usually allows good wetting of the surface.

The method may be further provided, wherein the contact angle of the organic solution when deposited on an area of the bank structure extending away from the first slope from the pinning point is 50 ° or greater. This contact angle generally does not allow good wetting of the surface, that is, non-wetting.

According to a second aspect of the present invention, there is provided an electronic device including a substrate having a surface layer and a bank portion structure defining a well on the surface layer, the bank portion structure including an electrically insulating material and having one of the surface layers surrounding the surface layer. A region to thereby define a sidewall of the well, the surface layer region including a first electrode, and the device further including a second electrode and a semi-conductive material disposed between the first electrode and the second electrode, wherein: the The side wall has a first inclined surface extending from the surface layer region and a second inclined surface extending from the first inclined surface, wherein the second inclined surface is steeper than the first inclined surface; and the device includes a layer structure having at least one layer, at least one The layer is a solution-treatable layer, the layer structure has the semi-conductive material and is disposed between the first electrode and the second electrode, wherein: at least one of the solution-treatable layer has The pinning points at the points where the first inclined plane is spaced apart, the solution-treatable layer is disposed on the surface layer region and the first inclined plane and the second inclined plane of the side wall.

Therefore, and similar to the first aspect, the embodiment may provide a pinning point for the (several) solution-treatable layer, the pinning point deviating from a straight line by having a different slope along its entire length Separate from the surface layer area. This in turn can reduce the risk of leakage paths or short circuits between electrodes (eg, anode and cathode) on either side of the solution-deposited layer. For example, any leakage path between the anode and the cathode along the boundary of the OLED's preferably high-resistance HIL is preferably extended to have a sufficiently high resistance to prevent leakage, otherwise, the leakage may ( For example) the efficiency, reliability and / or service life, color change, etc. are significantly degraded.

Considering the device structure more specifically, it should be noted that the surface layer may include one of an electrode (eg, an anode) and / or a partially reflective layer. For the bottom emission device embodiment, the table The surface layer (eg, tin oxide, such as indium tin oxide (ITO)) and the substrate (glass) are preferably at least partially transparent. A separate sub-layer (e.g., a silver layer) of the surface layer may provide a partially reflective layer as described above, which may be configured to form a size that may be sufficiently small to allow narrower results from the light emitting device Optical cavity with visible quantum effects in the emission spectrum, or in particular, a microcavity. For a device including this (eg, Ag) reflective layer, the fabrication of the device may include: blanket Ag (alloy) deposition; blanket ITO deposition; patterning ITO to form at least one electrode; spin coating of the bank; And then the bank is patterned. Alternatively, the electrode layer of the surface layer can further function as a partially reflective layer.

The electronic device may be further provided, wherein when a solution for forming the solution-treatable layer disposed on the surface layer region is deposited on the first inclined plane and an area extending from the first inclined plane to the pinned second inclined plane When at least one of them is on, the contact angle of the solution is 10 ° or less. Additionally or alternatively, when a solution for forming the solution-treatable layer disposed on the surface layer region is deposited on a surface region of the bank structure extending from the pinning point away from the first inclined plane, The contact angle of the solution is 50 ° or more. Therefore, this solution may have a contact angle of both 10 ° or less and 50 ° or more.

The electronic device may be further provided, wherein the bank structure includes at least one photoresist layer.

The electronic device may be further provided, wherein the photoresist layer has the point on the second slope and includes a fluorine-containing compound.

The electronic device may be further provided, wherein the bank structure includes a plurality of photoresist layers, and the photoresist layer has the first inclined surface.

The electronic device may be further provided, wherein the bank structure includes the photoresist layer having a fluorine-containing compound and the first inclined surface and the second inclined surface.

The electronic device may be further provided, wherein the first inclined surface has an inclined angle of less than or equal to 20 degrees (more preferably, less than 5, 10, or 15 degrees) with respect to the surface layer. This angle may be along the first inclined plane and / or specifically the first inclined plane is in contact with the surface layer. The average of the cases.

The electronic device may be further provided, wherein the first inclined surface extends up to a thickness of the bank structure at a boundary with the second inclined surface of less than 300 nm, preferably less than 200 nm (where the thickness is a height difference from the surface layer), Preferably, at least one of the first inclined surface and the second inclined surface extends along the thickness of the bank structure from 100 nm to 150 nm (therefore, the height traversed by the first inclined surface and / or the second inclined surface is better The ground is in the range of 100 nm to 150 nm; in the case where the bank structure is formed by a plurality of layers and each has an inclined surface, at least one (for example, the first inclined surface preferably crosses a height of 100 nm to 150 nm).

The electronic device may still be further provided, wherein the sidewall extends from the surface area to provide a bank structure thickness of at least 300 nm, preferably at least 1 μm. Therefore, the maximum height of the sidewall above the surface layer is preferably at least 300 nm. In an embodiment, this maximum height is advantageously thick enough to withstand dry etching steps, such as RIE.

The electronic device may be further provided, wherein the first inclined surface extends along the surface layer over a length of at least 1 μm, preferably the second inclined surface extends along the surface layer over a length of at least 8 μm, preferably The side wall (at least the first inclined surface and the second inclined surface) extends along the surface layer to a length of at least 10 μm.

The electronic device may be further provided, wherein the device is a light emitting device, and wherein the solution-processable layer includes an organic semiconductive material for providing a hole injection layer (HIL), and preferably the light emitting device is an OLED. In addition, at least one of the solution-treatable layers may include another organic semi-conductive material disposed above the material for providing the HIL, wherein the other organic semi-conductive material is used to provide an intermediate layer (IL) or Light emitting layer (EL).

When the electronic device is a light-emitting device such as an OLED, it is preferable that one of the first electrode layer and the second electrode layer (any one, that is, the first electrode layer or the second electrode layer; If it is an embankment emitter device, it is preferably a second electrode layer) It is light-transmissive (if it is an embankment emitter device, it is preferable that the substrate is also transmissive). This device preferably includes a substrate (e.g., between a (preferably, glass) substrate and a first electrode layer) Forming a partially light-reflective (preferably complete) layer of a microcavity having the reflective electrode layer (preferably metallic, such as silver, and / or preferably blanket-deposited rather than patterned). This cavity may allow amplifying light and / or make the device more efficient.

Preferred embodiments are defined in the accompanying independent technical solution.

Any one or more of the above aspects of the preferred embodiment and / or any one or more of the above optional features may be combined in any substitution manner.

11‧‧‧ surface layer

12‧‧‧ Embankment structure layer

13‧‧‧ surface layer area

14‧‧‧Photoresist layer

15‧‧‧ surface

21‧‧‧ surface layer

22‧‧‧ Embankment structure layer

23‧‧‧ surface layer area

24‧‧‧Photoresist layer

25‧‧‧ surface

31‧‧‧ surface layer

32‧‧‧The first bank layer

33‧‧‧ surface layer area

34‧‧‧ surface

41‧‧‧ surface layer

42‧‧‧bank layer

43‧‧‧ surface layer area

44‧‧‧area

45‧‧‧ surface

51‧‧‧ surface layer

52‧‧‧bank layer

53‧‧‧ surface layer area

54‧‧‧area

55‧‧‧ surface

61‧‧‧ surface layer

62‧‧‧bank layer

63‧‧‧ surface layer area

64‧‧‧ area

65‧‧‧ surface

L1‧‧‧Soluble treatment layer / layer

L2‧‧‧Another solution treatment layer / layer

S1‧‧‧First slope / slope

S2‧‧‧Second bevel / bevel

For a better understanding of the invention and to show how it can be implemented, reference will now be made by way of example to the accompanying drawings, in which: FIG. 1a shows an exemplary fabrication method in which a fluorinated dyke material is spin-coated to an anode (e.g. , ITO), and photo-patterned to provide a well; Figure 1b shows the use of a single masking step to define a long anode-to-cathode distance for part of the transmissive area in the mask; Figure 1c shows the RIE with a short sidewall path length Patterned bank pixel (top to middle pattern) and, conversely, an implementation that provides a longer path length pixel (bottom pattern) according to an embodiment; FIG. 1d shows a pixel having a process formed from FIG. 1a or FIG. 1b. The device of the bank; Figure 2 shows the service life (device stability) curve; Figure 3a shows the dual development process; Figure 3b shows the double mask process using a single patterned layer; Figure 3c shows a single mask using a single patterned layer Partial transmissive process of the mask; Figure 3d shows a single masking process using a single patterned layer using a reflective area and a sub-threshold exposure dose; Figures 4a to 4e show scanning electron beams in cross section Microscopic image; FIG. 5 shows the variation across the active region of the device and the thickness of the HIL + IL emission CIE values; FIG. 6 illustrates the structure of the boundary of the steep portion of the bank to be eliminated; and FIG. 7 shows a histogram of the thickness measurement of the HIL region for a standard bank example and a shallow bank example.

In general, the layers of an exemplary OLED embodiment may be as follows:

A substrate, such as glass, preferably has a surface layer including an ITO (80 nm) electrode and optionally a reflective layer (eg, Ag) for forming a microcavity

˙HIL (hole injection layer) = inkjet printing using ND3202b from Nissan Chemical Industries

˙IL (middle layer)

˙EL (light emitting layer), which includes a light emitting polymer LEP, such as a green light emitting polymer.

Embodiments generally provide, for example, a single bank configuration with a longer path length to thereby reduce leakage current. For OLEDs, this path length can be between the anode surface (eg, ITO) and the HIL-IL-EL coincident fluid pinning point. These longer path lengths next to the high-resistance HIL can form a high-resistance path for any potential parasitic leakage currents and / or non-emissive edge device diodes. This bank structure has proven to improve the stability of OLED service life.

Several bank processes are contemplated for this embodiment in the following description. For example: (i) a developed hydrophobic bank through secondary layer patterning and partially reactive ion etching (RIE); (ii) unpatterned hydrophobic edges with partially exposed pixel edges due to the RIE masking layer (Iii) dual development process; (iv) dual masking process using a single patterned layer; (v) translucent (leak) process using a single masking portion of a single patterned layer; and (vi) utilization A single masking process using a single patterned layer for reflective areas and sub-threshold exposure doses.

Examples of these processes may provide a single developed hydrophobic bank with a partially plasma etched bracket. Advantageously, a single developed hydrophobic bank and subsequent patterning steps The oxygen plasma is allowed to clear the ITO area and also partially etch a predefined amount of the bank. The ITO and part of the etched bank are preferably hydrophilic, allowing the HIL to wet up to the unetched area of the hydrophobic bank. The HIL section has a bank below to the HIL pinning point, which will share this pinning point with IL and EL. The working anode is advantageously separated from the cathode by a long and preferably device-designable distance, thus (for example) causing lower current leakage when using a high-resistance HIL.

The single bank structure for OLEDs can therefore be improved by providing a wet anode surface (ITO) and a longer path length between the anode surface and the HIL-IL-EL coincident fluid pinning point. These longer path lengths provide a high-resistance option for any potential parasitic leakage current. Embodiments allow the anode-to-cathode path to be extended in a controlled manner and thus tunable to reduce parasitic leakage currents, which in turn can improve device efficiency.

Additionally or alternatively, these processes can reduce the complexity of the structure relative to the double bank structure.

Figure 1a shows an exemplary fabrication method in which a fluorinated bank material (bank structure layer 12) is spin-coated onto an anode (surface layer 11) (e.g., ITO) and photo-patterned to provide a well (see The area above the surface layer area 13). The photoresist layer 14 above the material of the bank is then light-patterned and additional processing is performed to remove the section of the bank, thereby extending the insulating bank of the bank. This additional processing may include reactive ion etching applied partially to etch through the bank material. The photoresist is removed after additional processing. It is therefore possible to vary the profile of the bank material at the edges of the well so that the profile provides a longer path length. As shown by only illustrative thin lines along the first slanted surface s1 and the second slanted surface s2 in FIG. 1, this etching results in a longer electrical path to the surface 15 exposed by removing the photoresist.

The alternative method shown in Figure 1b uses a single masking step with partial transmissive areas in the mask to define a long anode-to-cathode distance to the bank of the bank; the RIE step preferably etches the presence of a thin positive masking layer Pixel edge. RIE can etch out pixels, where the edges of the pixels are exposed to the plasma due to the thin shielding layer. You can use this method by changing The size of the masked pixels of the developed banks relative to the size of the RIE patterned openings is adjusted to adjust the anode-to-cathode distance and therefore the amount of parasitic leakage current. This is in contrast to simple light-patterned bank pixels and / or simple RIE-patterned bank pixels, each of which will typically give a short path length from the anode to the cathode (blue area) and its length is usually not adjustable. Specifically, FIG. 1 b shows the surface layer 21, the bank structure layer 22, the surface layer region 23, the photoresist layer 24, the inclined surfaces s1 and s2, and the surface 25.

(Figure 1c shows the fabrication of RIE-patterned bank pixels (top-to-middle pattern) with short sidewall path lengths and conversely, pixels with longer path lengths (bottom pattern) according to an embodiment).

Figure 1d shows a bank portion formed with the process embodiment described above and further comprising a solution-treatable layer L1 in the form of a HIL (hole injection layer) and an IL (intermediate layer) and / or a LEP (light emitting polymer) Another device for layer L2 which can be processed in the form of a layer. As seen from Figure 1d, the HIL, IL, and LEP fluids have coincident pinning points. The IL and / or LEP layer may be covered by an EIL (electron injection layer), which in turn may be covered by a cathode layer. Preferably, the EIL does not share the pinning points of the layers L1 and L2, but instead covers these layers and extends across adjacent areas of the embankment structure. The cathode layer may preferably be deposited directly on the EIL, which in an embodiment is conformally coated with the EIL to extend across the layers and the adjacent regions.

In view of the above, embodiments provide a single bank structure with a long insulated bracket as opposed to a (distance) dual bank system that separates the anode pinning point from the cathode. A single hydrophobic bank can be used and a subsequent patterning process can be applied to elongate the bank of the bank. In an embodiment, the ITO and the bank of the bank can be hydrophilic, allowing HIL to wet up to a predefined point, where the bank becomes hydrophobic (ink pinning point). The HIL section will have a bank below to the HIL pinning point, which will share this pinning point with IL and LEP. By using a high-resistance HIL, the working anode can be separated from the cathode by a long (and device-designable) distance.

Embodiments allow the anode-to-cathode path length to be increased in a controlled manner and thus provide a tunable process to reduce parasitic leakage currents, which results in a more stable life test (And repeatable) device illumination. In contrast, a single bank formed by a standard photolithography process or a more complex but standard RIE (reactive ion etching) process can provide an inexpensive method for pixel (bank) definition. However, two standard techniques can keep short anode-to-cathode path lengths at the edge of a pixel (device). It has been shown that the short path length (short bracket) between the anode (ITO) surface and the HIL-IL-EL-cathode coincident pinning point causes an unstable device when driven over time.

FIG. 1a may alternatively be considered to show an embodiment of a process flow for a single bank with a long bracket. This process involves a two-step patterning process to create a long bank. The length of the bracket from the anode (ITO) to the ink pinning point can be controlled by the second patterning step, and the depth of the bracket can be controlled similarly to provide sufficient electrical insulation from the anode. This embodiment can be used to adjust the anode-to-cathode distance by changing the masked design size of the pixel of the developed bank relative to the pixel size of the secondary partial patterning step (see only illustrative thin lines) and thus the parasitic leakage The amount of current. And (for example) simple light-patterned dyke pixels or simple RIE patterned dyke pixels (each of which will usually give a short path length (<1 μm) from anode to cathode and its length is usually not adjustable ( Except by the height of the bank)), this embodiment results in a long carriage device (eg,> 2 μm).

A longer anode-to-cathode distance can also be achieved by making the bank higher, however, this will usually have a negative effect on the HIL-IL-EL contour at the edge of the pixel, making it thicker and causing uneven emission.

Preferably, the HIL, IL, and EL in the embodiments all have coincident pinning points. This can cause a long leakage path from the anode to the cathode, where a HIL (conductive hole injection layer) is connected to the metal cathode. This effect is minimized by using a high-resistance HIL and then separating the anode (ITO) from the cathode for a long lateral HIL distance (as described above).

Considering the results of the device, the stability of the device during the life test showed a significant improvement. In an embodiment, the long bracket significantly reduces the pixel edge diode effect (which is a non-emissive thin diode) by increasing the resistance (path length) to a certain point of the HIL-IL-EL compliance.

Figure 2 shows a graph of service life (device stability). It can be seen that the initial bright wave (increased illuminance at a fixed current) for a single crater short bracket device (dotted curve) is significantly different between the devices. This may be due to the existence of a vertical leakage path, which "burned out" during the test, causing current to be redistributed. In Fig. 2, a single bank long bracket (continuous curve) shows a much tighter distribution of the magnitude of the bright wave, which means that the effect may be independent of the leakage current. It is possible to use this embankment to assess material and process stability. For a single bank configuration, the service life (device degradation) is more predictable and the dependence on the device effects at the edge of the pixel is much lower. Therefore, a single hydrophobic bank with a long bracket has proven to improve the lifetime stability of OLEDs.

Considering the complexity of the process, it should be noted that the simplified process method can produce a single hydrophobic bank with a long bracket, and / or reduce the relative to the double bank with a single bank method with a long insulating bracket to reduce leakage. The complexity of construction. Advantageously, this simplified embodiment allows the anode-to-cathode path to grow in a controlled manner, and thus tunably reduces parasitic leakage currents, which reduces device efficiency. Embodiments cover an alternative simplified method of achieving a single bank pixel.

Further attention is paid to the complexity of the process. The process method of FIG. 1a involves a developed hydrophobic bank through secondary layer patterning and partially reactive ion etching (RIE). This may require two lithographic patterning loops (e.g., removal, baking, coating, baking, exposure, baking, development, bank curing, coating, exposure, development) plus a RIE step and a positive resist Agent stripping.

However, for example, compared to the embodiment using two photo-patterning steps plus reactive ion etching to produce a long bracket (as shown in Figure 1a) required for OLED device stability, the embodiment of Figure 1b can The process of providing a long developed single developed hydrophobic bank is simplified.

However, the first simplified display as shown in Figure 1b shows an unpatterned hydrophobic bank with partially exposed pixel edges due to the RIE masking layer. This process eliminates the need for masking and development steps on the first patterned loop.

An alternative simplification is shown in Figure 3a, which is illustrated as a dual development process. This process can be eliminated Eliminates need for RIE and stripping steps. Preferably, the first patterned bank portion is thin and has a shallow slope to the pixel. Preferably, a first thin bank layer is deposited, such as by spin coating, and hardened. The thin layer is then light patterned and subsequently developed to expose areas of the anode, the thin layer having a gentle slope to the exposed area. Then another bank layer is deposited, light patterned and developed. Advantageously, a species such as a fluorine species (e.g., a fluorine moiety) within the other bank layer migrates to the top surface of the other bank layer during baking of the other layer, such that the top surface and the other bank layer The side walls of the layer (preferably also the side walls of the thin layer) are less wettable by the solution deposited on the exposed area. Specifically, Fig. 3a shows a surface layer 31, a first bank layer 32, a surface layer region 33, and a second bank layer having a surface 34 and slopes s1 and s2.

Figure 3b shows an alternative simplification in the form of a dual masking process using a single patterned layer. This process does not use a single patterning process for a positive resist layer, but it may require two photomasks and a double exposure step. The upper mask (Mask 2) may be a gradient mask to more clearly define the slopes s1 and s2. Specifically, FIG. 3b shows the surface layer 41, the bank layer 42, the surface layer region 43, the inclined surfaces s1 and s2, and the surface 45, where the region 44 is between the bank layer layer and the region 44 or below the surface 45 ( (Several) the second area of the first area.

Figure 3c shows another alternative simplification: a single masked part transmissive (leak) process using a single patterned layer. This process does not use a single patterning step process of a positive resist layer, but it may require a higher-cost light mask, but uses a single exposure step. Specifically, FIG. 3c shows the surface layer 51, the bank layer 52, the surface layer region 53, the slopes s1 and s2, and the surface 55, where the region 54 is between the bank layer and the region 54 or below the surface 55 ( (Several) the second area of the first area. Partially transmissive (eg, sub-resolution characterization) masks can be gradient masks to more clearly define the bevels s1 and s2.

Figure 3d shows yet another alternative simplification: a single masking process using a single patterned layer using reflective areas and sub-threshold exposure doses. This is a single patterning step process that does not use a positive resist layer but uses a single exposure step. The design of the above layers may incorporate reflective areas for creating higher dose areas to completely crosslink the bank. You can use this method to adjust the anode to The cathode distance and thus the amount of parasitic leakage current are adjusted. Specifically, FIG. 3d shows the surface layer 61, the bank layer 62, the surface layer region 63, the slopes s1 and s2, and the surface 65, where the region 64 is the first region (several) of the bank layer relative to the surface 65 The second area.

This is in contrast to light-patterned individual bank pixels and / or RIE-patterned bank pixels, each of which will typically give a short path length from the anode to the cathode (blue area) and its length is usually not adjustable (see Figure 1c).

For different methods and embodiments as described above, FIG. 4 shows a plurality of example bracket bank images. Figure 4a shows a double-developed long bracket bank, Figure 4b shows a double-developed long bracket bank with HIL, Figure 4c shows a long-bracket bank through a notch in RIE, and Figure 4d shows a single developed bank And Figure 4e shows a single developed bank with a HIL (short (no) bracket).

The flat thickness variation curve of HIL + IL is required to maximize the efficiency of the OLED device on the microcavity platform. In the inkjet printing apparatus, the thickness curve depends on the underlying bank structure. The following is a detailed description of the preferred bank profile in order to achieve an appropriate flat thickness variation curve in a single bank inkjet printing device. Advantageously, this profile can provide a gradual transition from the embankment bracket to the active area, thereby allowing the printed HIL to form a flat profile suitable for microcavity OLED devices.

Specifically considering the use of a flat film profile with a single bank of a gradation bracket + anhydrous HIL, the embodiment can provide a gradual transition from the cradle of the bank to the action zone, thus allowing the printed HIL to form a flat profile suitable for microcavity OLED devices. The flat thickness variation curve of HIL + IL is required to maximize the efficiency of the OLED device on the microcavity platform. In the inkjet printing apparatus, the thickness curve depends on the underlying bank structure. The embodiment provides a bank profile suitable for achieving a flat thickness variation curve in a single bank inkjet printing device.

Achieving maximum performance at the best possible color point often requires precise control of layer thickness and contours in microcavity OLED devices. In addition, if there is significant unevenness in the contour area of the HIL + IL layer, non-optimal output coupling will be presented and performance will be impaired.

For example, the width profile of the HIL + IL thickness of an inkjet printing device is shown in FIG. 5. The visible pixel edge region display is significantly thicker than the center region. In these regions, the CIE coordinates are shifted according to the target color point. This leads to a compromise in overall device performance.

Bank types have been developed to minimize the amount of edge thickening and thus improve printing performance. The sharp transition from the bracket to the ITO caused the edges to thicken because the HIL could not closely follow the contour of the bank.

An embodiment with a gradual embankment bracket is shown in FIG. 6, which includes a close-up representation of the upper annular region in the lower diagram, where the lower diagram on the right-hand side is shown in comparison with the embodiment without gradual tilt (left-hand side) This tilt.

The use of this gradient bracket bank type has been shown to maximize the performance of the device on the inkjet printing platform, making it comparable to SC (spin-coated device) data (showing data for devices that emit green light):

Where DE = D (u'v '), the u', v 'definitions ("CIELUV") of the CIE 1976 color space are used. This watch shows that inkjet printing devices, such as the gradual carriage bank device, are comparable to spin-coated devices.

Further in this regard, it should be noted that the conversion from CIExy of the 1931 CIE XYZ color space to CIE u'v 'of CIELUV is given by the following (ie, CIE1931 → CIE1976): And the color difference metric DE defined using u ', v' of CIELUV is given by: , That is, the Euclidean distance in CIE 1976 space.

For embodiments such as the "gradient bracket bank" device described above, the CIEx and Y Target (NTSC) for green launches are 0.213 and 0.724, respectively. CIExy was obtained using a Minolta colorimeter, and dE was calculated using CIExy.

dE = 0.02 is a preferred upper limit acceptable in the examples, however, 0.005, 0.01, or 0.015 is more desirable.

FIG. 7 shows a histogram showing that the standard bank has a thicker area ratio than the embodiment with the gradient bracket bank. The histogram is obtained by measuring the thickness at regularly spaced points across the action zone above the surface layer region surrounded by the sidewalls of the bank structure. The device with a "standard bank" is a device with a long bracket of substantially constant thickness similar to that shown in the upper part of Figure 6. A device having a "shallow bank" has a long bracket that tapers toward the surface layer of the device, such as a first inclined surface that preferably has an angle of less than 5 degrees, 10 degrees, 15 degrees, or 20 degrees. The "shallow bank" device has a narrower thickness distribution than the "standard bank" device, thus allowing more controlled output coupling (input coupling in light absorbing devices) in OLEDs.

There is no doubt that those skilled in the art will come up with many other effective alternatives. It will be understood that the present invention is not limited to the illustrated embodiments and encompasses modifications apparent to those skilled in the art, which fall within the scope of the patent application attached hereto.

Claims (22)

A method of fabricating an electronic device including a substrate having a surface layer and a bank structure defining a well on the surface layer, the bank structure including an electrically insulating material and having a region surrounding the surface layer to thereby define the well A sidewall, the surface layer region including a first electrode and a partially reflective layer configured to form a microcavity, and the device further includes a second electrode and a semi-conductive material disposed between the first electrode and the second electrode The method includes forming the bank structure having the side wall including a first inclined surface extending from the surface layer region and a second inclined surface extending from the first inclined surface, wherein the second inclined surface is steeper than the first inclined surface, The side wall has a discontinuity in surface energy at a point at which the second inclined plane is spaced from the first inclined plane; a layer structure having at least one layer is formed, and the layer structure is disposed on the first electrode and the second electrode And has the semi-conductive material therebetween, wherein the forming the layer structure includes: depositing an organic solution on the surface layer region and the first inclined surface and the second inclined surface of the side wall to This layer of solution to be treated, wherein the organic solution was deposited wets the first inclined surface and the second inclined surface until the staple of the discontinuity of the surface energy of tie points; and drying the deposited organic solution. The method of claim 1, comprising: depositing at least another solution over the solution-treatable layer, wherein the at least another solution is wetted to the pinning point; and drying the deposited at least another solution. The method as claimed in claim 1 or 2, wherein the forming the bank structure includes: forming a first bank layer including a photoresist on the surface layer of the substrate; photo-patterning and developing the first bank layer to Expose the area of the surface layer; deposit a fluorinated photoresist solution on the first bank portion layer and the exposed area of the surface layer to form a second bank portion layer; and bake to make the second bank portion The layer becomes hard, wherein the fluorinated compound of the fluorinated photoresist solution migrates to the surface of the second bank layer during the baking to increase the contact angle between the organic solution and the surface; and photo-patterning and developing the The second bank layer re-exposes the region of the surface layer and exposes an area of the first bank layer, so that the first bank layer region has the first slope and the second bank layer has the second A bevel, wherein the increased contact angle is higher than the contact angle of the organic solution with the first bevel and the second bevel, and the pinning point is on the surface of the second bank layer with the migrated fluorine-containing compounds At the border. The method of claim 1 or 2, wherein the forming the bank structure includes forming a bank structure layer by depositing a fluorinated photoresist solution on the surface layer, and drying the deposited solution to make the bank The structure layer becomes hard, wherein the fluorine-containing compound of the fluorinated photoresist solution migrates to the surface of the bank structure layer during the baking to increase the contact angle between the organic solution and the surface; on the bank structure layer Depositing and drying the photoresist layer, and photo-patterning and developing the photoresist layer; a dry etching step for etching the bank structure layer through the developed photoresist layer to expose the surface layer region so that The etched bank structure layer has the side wall surrounding the exposed surface layer region and includes the first inclined surface and the second inclined surface; and removing the developed photoresist layer to expose the surface of the bank structure layer, The exposed surface includes the migrated fluorine-containing compounds, wherein the surface energy discontinuity is at an interface between the exposed surface including the migrated fluorine-containing compounds and the etched sidewall. The method of claim 4, wherein the forming the bank structure includes developing and photo-patterning the bank structure layer to expose the surface layer region surrounded by the sidewall of the bank structure layer, wherein the structure on the bank structure Depositing the photoresist layer on the layer includes depositing a photoresist solution on the photo-patterned bank structure layer, and developing the photoresist layer includes re-exposing the surface layer region and exposing the surface layer region The dry etching step extends the exposed area by thinning the bank structure layer to form the first inclined surface and the second inclined surface. The method of claim 5, wherein the light patterning the photoresist layer includes radiating the photoresist layer through a mask having non-transmissive regions, partially transmissive regions, and fully transmissive regions; and developing the light The resist layer includes completely removing a region of the photoresist and partially removing the photoresist region exposed to the radiation through the partially transmissive region. The method of claim 6, wherein the dry etching step includes reactive ion etching using an oxygen plasma. The method of claim 1, wherein the forming the bank structure comprises: forming a bank layer by depositing a fluorinated photoresist solution on the surface layer; and baking to harden the bank layer, wherein The fluorine compound of the photoresist solution migrates to the surface of the bank layer during the baking to thereby increase the contact angle between the organic solution and the surface; the light patterning of the hardened bank layer includes: A first radiation dose irradiates a first area of the bank layer and a second radiation dose irradiates a second area of the bank layer, the second radiation dose is less than the first radiation dose; developing the bank layer to expose the surface The area of the layer and partially remove an area of the bank layer irradiated with the second radiation dose, the partial removal thereby providing the surrounding the exposed area with the first slope and the second slope A side wall, wherein the pinning point is at a boundary between the surface of the bank layer having the migrated fluorine-containing compounds and the side wall. The method of claim 8, wherein the light patterning includes radiating the bank layer through the first mask and the second mask simultaneously, and wherein irradiating the first region with the first dose includes passing through the first A completely transmissive area of the mask and the second mask radiates the first area, and the radiating the second area with the second dose includes passing through each of the first mask and the second mask At least a partially transmissive area radiates the second area; and / or the light patterning includes radiating the bank layer through a mask having a partially transmissive area and a more transmissive area, wherein the radiation is emitted at the first dose The first region includes radiating the first region through the more transmissive region, and irradiating the second region at the second dose includes radiating the second region through the partially transmissive region; and / or the method The method includes depositing a reflector layer on an area of the surface layer, wherein: the depositing the fluorinated photoresist solution deposits the fluorinated solution on the reflector layer and the surface layer; and the photo-patterning includes passing through a mask The cover radiates the bank layer, wherein the radiation covers the first area packet The first portion of the region directly absorbed through the mask receiving the first dose of the mask and is absorbed from the first receiving reflected by the reflector layer back to a portion of the first region of the dosage. The method according to any one of claims 1, 2, 8 and 9, wherein the electronic device is an optoelectronic device. The method of claim 10, wherein the electronic device is a light emitting device or a light absorbing device. The method of any one of claims 1, 2, 8 and 9, wherein the electronic device is an OLED and the organic solution is used to provide a hole injection layer (HIL). The method of claim 12, further comprising forming at least another solution-treatable layer on the solution-treatable layer and between the first electrode and the second electrode, the other solution-treatable layer for providing an intermediate Layer (IL) and / or light emitting layer (EL). The method according to any one of claims 1, 2, 8 and 9, wherein: the organic solution is deposited on at least one of the first bevel and a second bevel region extending from the first bevel to the pinning point. The contact angle at the time is 10 ° or less; and / or the contact angle at which the organic solution is deposited on an area of the bank structure extending away from the first slope from the pinning point is 50 ° Or greater. An electronic device including a substrate having a surface layer and a bank structure defining a well on the surface layer, the bank structure including an electrically insulating material and having a region surrounding the surface layer to thereby define a sidewall of the well, the The surface layer region includes a first electrode and a partially reflective layer configured to form a microcavity, and the device further includes a second electrode and a semi-conductive material disposed between the first electrode and the second electrode, wherein: The side wall has a first inclined plane extending from the surface layer region and a second inclined plane extending from the first inclined plane, wherein the second inclined plane is steeper than the first inclined plane; and the device includes a layer structure having at least one layer, at least A layer is a solution-treatable layer, the layer structure has the semi-conductive material and is disposed between the first electrode and the second electrode, wherein: at least one of the solution-treatable layer has The pinning points at the points where the first inclined plane is spaced apart, the solution-treatable layer is disposed on the surface layer region and the first inclined plane and the second inclined plane of the side wall. The electronic device of claim 15, wherein the bank structure includes at least one photoresist layer. The electronic device of claim 16, wherein: the photoresist layer has the point on the second slope and includes a fluorine-containing compound; and / or the bank structure includes a plurality of photoresist layers, the photoresist The layer has the first inclined surface; and / or the bank structure includes the photoresist layer having the fluorine-containing compounds and the first inclined surface and the second inclined surface. The electronic device according to any one of claims 15 to 17, wherein the first inclined surface has a degree of less than or equal to 20 degrees with respect to the surface layer. The electronic device of any one of claims 15 to 17, wherein: the first inclined plane extends until less than 300 nm at a boundary with the second inclined plane; and / or the sidewall extends from the surface region to provide a bank of at least 300 nm Part of the structure thickness; and / or the first inclined surface extends along the surface layer over a length of at least 1 μm. The electronic device according to any one of claims 15 to 17, wherein the device is a light emitting device, and wherein the solution-treatable layer includes an organic semiconductive material for providing a hole injection layer (HIL). The electronic device as claimed in claim 20, wherein the light emitting device is an OLED. The electronic device of claim 21, wherein at least one of the solution-treatable layers includes another organic semi-conductive material disposed above the material for providing the HIL, and the other organic semi-conductive material is for providing an intermediate Layer (IL) or light emitting layer (EL).